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authorTheodore Ts'o <tytso@mit.edu>2002-05-11 13:00:22 -0400
committerTheodore Ts'o <tytso@mit.edu>2002-05-11 13:00:22 -0400
commit583a1ce5d1b225a6b01fc2b30a3bcb21fd0d48c9 (patch)
tree24d0abe0bbd63441e8b50564e459761bf9c737cd /ext2ed
parent7de6577cd93041742fad3da0046978793ebb978f (diff)
Check in ext2ed version 0.1
Diffstat (limited to 'ext2ed')
-rw-r--r--ext2ed/COPYRIGHT346
-rw-r--r--ext2ed/Makefile78
-rw-r--r--ext2ed/README101
-rw-r--r--ext2ed/blockbitmap_com.c265
-rw-r--r--ext2ed/dir_com.c675
-rw-r--r--ext2ed/disk.c238
-rw-r--r--ext2ed/doc/Ext2fs-overview-0.1.sgml898
-rw-r--r--ext2ed/doc/ext2ed-design-0.1.sgml2102
-rw-r--r--ext2ed/doc/ext2ed.872
-rw-r--r--ext2ed/doc/user-guide-0.1.sgml1189
-rw-r--r--ext2ed/ext2.descriptors407
-rw-r--r--ext2ed/ext2_com.c97
-rw-r--r--ext2ed/ext2ed.conf79
-rw-r--r--ext2ed/ext2ed.h438
-rw-r--r--ext2ed/file_com.c564
-rw-r--r--ext2ed/general_com.c748
-rw-r--r--ext2ed/group_com.c182
-rw-r--r--ext2ed/init.c607
-rw-r--r--ext2ed/inode_com.c436
-rw-r--r--ext2ed/inodebitmap_com.c214
-rw-r--r--ext2ed/main.c374
-rw-r--r--ext2ed/super_com.c159
-rw-r--r--ext2ed/win.c169
23 files changed, 10438 insertions, 0 deletions
diff --git a/ext2ed/COPYRIGHT b/ext2ed/COPYRIGHT
new file mode 100644
index 00000000..5585eb6e
--- /dev/null
+++ b/ext2ed/COPYRIGHT
@@ -0,0 +1,346 @@
+EXT2ED is hereby placed under the terms of the GNU General Public License.
+Follows the GNU license.
+
+Gadi Oxman, August 1995
+
+---------------------------------------------------------------------------
+
+ GNU GENERAL PUBLIC LICENSE
+ Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+ 675 Mass Ave, Cambridge, MA 02139, USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users. This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it. (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.) You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+ To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+ For example, if you distribute copies of such a program, whether
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+ We protect your rights with two steps: (1) copyright the software, and
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+ Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software. If the software is modified by someone else and passed on, we
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+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ GNU GENERAL PUBLIC LICENSE
+ TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+ 0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
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+ 10. If you wish to incorporate parts of the Program into other free
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+ NO WARRANTY
+
+ 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
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+
+ END OF TERMS AND CONDITIONS
+
+ Appendix: How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
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+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) 19yy <name of author>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+ Gnomovision version 69, Copyright (C) 19yy name of author
+ Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary. Here is a sample; alter the names:
+
+ Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+ `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+ <signature of Ty Coon>, 1 April 1989
+ Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs. If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library. If this is what you want to do, use the GNU Library General
+Public License instead of this License.
diff --git a/ext2ed/Makefile b/ext2ed/Makefile
new file mode 100644
index 00000000..ec5a86f0
--- /dev/null
+++ b/ext2ed/Makefile
@@ -0,0 +1,78 @@
+# /gadi/project/Makefile
+#
+# Makefile for the extended-2 filesystem editor.
+#
+# First created : April 8 1995
+#
+# Copyright (C) 1995 Gadi Oxman
+
+# ------------------------------------------------------------------------
+# EXT2ED, ncurses and readline
+# ------------------------------------------------------------------------
+#
+# EXT2ED requires the ncurses and readline libraries.
+#
+# Please define OLD_NCURSES below if you are using an old version of ncurses.
+# I don't know the exact threshold, but from my experience this flag is needed
+# for version 1.8.5 and not needed for 1.9.2c and up. In any case, you will
+# notice immediately that this flag is wrong - The main window will be totally
+# corrupted.
+
+# FLAGS = -DOLD_NCURSES
+
+# Define the directories below to insure that the compiler will find the
+# required ncurses and readline include files / libraries. Be sure that you
+# don't mix two two versions of ncurses.
+
+# NCURSES_INCLUDE = -I/usr/local/include -I/usr/local/include/ncurses
+# NCURSES_LIB = -L/usr/local/lib
+# READLINE_INCLUDE = -I/usr/include -I/usr/include/readline
+# READLINE_LIB = -L/usr/lib
+
+# ------------------------------------------------------------------------
+# Install Directories
+# ------------------------------------------------------------------------
+
+# The executable will go into BIN_DIR.
+# The configuration file, log file, etc will go into VAR_DIR.
+# The manual page will go into MAN_DIR.
+# The EXT2ED documentation will go into DOC_DIR.
+
+BIN_DIR = /usr/bin
+VAR_DIR = /var/lib/ext2ed
+MAN_DIR = /usr/man/man8
+DOC_DIR = /usr/doc/ext2ed
+
+# ------------------------------------------------------------------------
+
+CC = gcc
+CCFLAGS = -O $(FLAGS) -DVAR_DIR=\"$(VAR_DIR)\" $(NCURSES_INCLUDE) $(READLINE_INCLUDE)
+LINKFLAGS = $(NCURSES_LIB) $(READLINE_LIB)
+LIBS = -lreadline -lncurses
+
+.c.o:
+ $(CC) $(CCFLAGS) $(INCLUDE_DIR) -c $<
+
+OBJS= main.o init.o general_com.o inode_com.o dir_com.o super_com.o \
+ disk.o win.o group_com.o file_com.o blockbitmap_com.o ext2_com.o \
+ inodebitmap_com.o
+
+ext2ed: $(OBJS)
+ $(CC) $(OBJS) $(LINKFLAGS) $(LIBS) -o ext2ed
+
+clean:
+ rm ext2ed *.o
+
+install: ext2ed
+ install -d $(VAR_DIR)
+ install -d $(DOC_DIR)
+ install -m 755 ext2ed $(BIN_DIR)
+ install -m 644 ext2.descriptors $(VAR_DIR)
+ install -m 644 ext2ed.conf $(VAR_DIR)
+ install -m 644 doc/ext2ed.8 $(MAN_DIR)
+ install -m 644 doc/user-guide-0.1.sgml $(DOC_DIR)
+ install -m 644 doc/user-guide-0.1.ps $(DOC_DIR)
+ install -m 644 doc/Ext2fs-overview-0.1.sgml $(DOC_DIR)
+ install -m 644 doc/Ext2fs-overview-0.1.ps $(DOC_DIR)
+ install -m 644 doc/ext2ed-design-0.1.sgml $(DOC_DIR)
+ install -m 644 doc/ext2ed-design-0.1.ps $(DOC_DIR)
diff --git a/ext2ed/README b/ext2ed/README
new file mode 100644
index 00000000..7d187f2f
--- /dev/null
+++ b/ext2ed/README
@@ -0,0 +1,101 @@
+ext2ed - The extended-2 filesystem editor, version 0.1
+------------------------------------------------------
+
+This is version 0.1 of ext2ed - The extended-2 filesystem editor.
+
+Documentation
+-------------
+
+ext2ed's documentation consists of three documents:
+
+1. The user's guide.
+2. Technical overview of the ext2 filesystem.
+3. The EXT2ED design and implementation document.
+
+Those documents are available in the doc directory, in linuxdoc-sgml and
+postscript formats.
+
+The documentation is also available online at:
+
+http://tochnapc2.technion.ac.il
+
+under the ext2ed section.
+
+Installation
+------------
+
+ext2ed requires the kernel sources and the readline and ncurses packages.
+Please edit the makefile if you are using an "old" version of ncurses (See the
+details below) or if gcc can't find the various header files and libraries.
+
+To install, simply issue a 'make' command to compile and a 'make install'
+command to install. I have also included an already compiled linux a.out
+binary.
+
+ext2ed and ncurses
+------------------
+
+ext2ed uses the ncurses library for terminal output. It is very important
+that ncurses will be properly installed on your system:
+
+1. Old versions of ncurses (around 1.8.5) need the OLD_NCURSES compile
+ time option in EXT2ED.
+
+ At least from 1.9.2c, this flag should not be used. I would recommend
+ upgrading the ncurses library to the newer versions.
+
+2. ncurses uses its own terminfo database rather then the termcap file.
+ It is important that the terminfo database will be found by ncurses.
+ If this is not the case, you will see on startup some lines which
+ refer to /etc/termcap. This will mean that there is a problem with
+ the terminfo database.
+
+3. Newer versions of ncurses (and the 1.3 series of the kernel) describe
+ the linux console in the entry 'linux' and not 'console', as it was
+ before. If you run ext2ed in the linux console, you should either
+ set your TERM environment variable to 'linux' or link
+ l/linux to c/console in the terminfo database.
+
+4. The percompiled binary was linked with ncurses 1.9.4 and will search
+ for the terminfo database on /usr/local/lib/terminfo. If you are
+ using it, and your 1.9.4 compatible terminfo database is not on the
+ directory above, use the TERMINFO environment variable to specify
+ an alternate location.
+
+Running ext2ed
+--------------
+
+For those of you who don't like reading lengthy articles, here are a few
+basic guidelines:
+
+1. Don't use ext2ed to change a mounted filesystem !
+
+ Using ext2ed in read-only mode on a mounted filesystem can be allowed
+ by using the configuration file option 'AllowMountedRead on'. However,
+ note that the displayed data will be unreliable.
+
+2. ext2ed currently can't handle filesystems bigger than 2 GB. I am
+ sorry for the inconvenience. This will hopefully be fixed in future
+ releases.
+
+3. Before running ext2ed, edit the configuration file
+ /var/lib/ext2ed/ext2ed.conf to suit your needs. The various
+ configuration options are documented there.
+
+4. Use the 'setdevice' command to open an ext2 filesystem.
+ e.g. 'setdevice /dev/hda1'.
+
+5. If the filesystem is an ext2 filesystem and ext2ed fails to
+ autodetect this, use the 'ForceExt2 on' configuration file option.
+
+6. The filesystem will always be opened in read-only mode. Feel free to
+ experiment, but take care with the 'enablewrite' command.
+
+-----------------------------------------------------------------------------
+
+Feel free to send me feedback with anything regarding to ext2ed.
+
+Enjoy,
+
+Gadi Oxman <tgud@tochnapc2.technion.ac.il>
+Haifa, August 23 1995 \ No newline at end of file
diff --git a/ext2ed/blockbitmap_com.c b/ext2ed/blockbitmap_com.c
new file mode 100644
index 00000000..355feb03
--- /dev/null
+++ b/ext2ed/blockbitmap_com.c
@@ -0,0 +1,265 @@
+/*
+
+/usr/src/ext2ed/blockbitmap_com.c
+
+A part of the extended file system 2 disk editor.
+
+-------------------------
+Handles the block bitmap.
+-------------------------
+
+This file implements the commands which are specific to the blockbitmap type.
+
+First written on: July 5 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+/*
+
+The functions in this file use the flobal structure block_bitmap_info. This structure contains the current
+position in the bitmap.
+
+*/
+
+void type_ext2_block_bitmap___entry (char *command_line)
+
+/*
+
+This function changes the current entry in the bitmap. It just changes the entry_num variable in block_bitmap_info
+and dispatches a show command to show the new entry.
+
+*/
+
+{
+ unsigned long entry_num;
+ char *ptr,buffer [80];
+
+
+
+ ptr=parse_word (command_line,buffer); /* Get the requested entry */
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");
+ refresh_command_win (); return;
+ }
+ ptr=parse_word (ptr,buffer);
+
+ entry_num=atol (buffer);
+
+
+ if (entry_num >= file_system_info.super_block.s_blocks_per_group) { /* Check if it is a valid entry number */
+
+ wprintw (command_win,"Error - Entry number out of bounds\n");
+ refresh_command_win ();return;
+ }
+
+
+
+ block_bitmap_info.entry_num=entry_num; /* If it is, just change entry_num and */
+ strcpy (buffer,"show");dispatch (buffer); /* dispatch a show command */
+}
+
+void type_ext2_block_bitmap___next (char *command_line)
+
+/*
+
+This function passes to the next entry in the bitmap. We just call the above entry command.
+
+*/
+
+{
+ long entry_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ entry_offset=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",block_bitmap_info.entry_num+entry_offset);
+ dispatch (buffer);
+}
+
+void type_ext2_block_bitmap___prev (char *command_line)
+
+{
+ long entry_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ entry_offset=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",block_bitmap_info.entry_num-entry_offset);
+ dispatch (buffer);
+}
+
+void type_ext2_block_bitmap___allocate (char *command_line)
+
+/*
+
+This function starts allocating block from the current position. Allocating involves setting the correct bits
+in the bitmap. This function is a vector version of allocate_block below - We just run on the blocks that
+we need to allocate, and call allocate_block for each one.
+
+*/
+
+{
+ long entry_num,num=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer); /* Get the number of blocks to allocate */
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ num=atol (buffer);
+ }
+
+ entry_num=block_bitmap_info.entry_num;
+ /* Check for limits */
+ if (num > file_system_info.super_block.s_blocks_per_group-entry_num) {
+ wprintw (command_win,"Error - There aren't that much blocks in the group\n");
+ refresh_command_win ();return;
+ }
+
+ while (num) { /* And call allocate_block */
+ allocate_block (entry_num); /* for each block */
+ num--;entry_num++;
+ }
+
+ dispatch ("show"); /* Show the result */
+}
+
+void type_ext2_block_bitmap___deallocate (char *command_line)
+
+/* This is the opposite of the above function - We call deallocate_block instead of allocate_block */
+
+{
+ long entry_num,num=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ num=atol (buffer);
+ }
+
+ entry_num=block_bitmap_info.entry_num;
+ if (num > file_system_info.super_block.s_blocks_per_group-entry_num) {
+ wprintw (command_win,"Error - There aren't that much blocks in the group\n");
+ refresh_command_win ();return;
+ }
+
+ while (num) {
+ deallocate_block (entry_num);
+ num--;entry_num++;
+ }
+
+ dispatch ("show");
+}
+
+
+void allocate_block (long entry_num)
+
+/* In this function we convert the bit number into the right byte and inner bit positions. */
+
+{
+ unsigned char bit_mask=1;
+ int byte_offset,j;
+
+ byte_offset=entry_num/8; /* Find the correct byte - entry_num/8 */
+ /* The position inside the byte is entry_num %8 */
+ for (j=0;j<entry_num%8;j++)
+ bit_mask*=2; /* Generate the or mask - 1 at the right place */
+ type_data.u.buffer [byte_offset] |= bit_mask; /* And apply it */
+}
+
+void deallocate_block (long entry_num)
+
+/* This is the opposite of allocate_block above. We use an and mask instead of an or mask. */
+
+{
+ unsigned char bit_mask=1;
+ int byte_offset,j;
+
+ byte_offset=entry_num/8;
+ for (j=0;j<entry_num%8;j++)
+ bit_mask*=2;
+ bit_mask^=0xff;
+
+ type_data.u.buffer [byte_offset] &= bit_mask;
+}
+
+void type_ext2_block_bitmap___show (char *command_line)
+
+/*
+
+We show the bitmap as a series of bits, grouped at 8-bit intervals. We display 8 such groups on each line.
+The current position (as known from block_bitmap_info.entry_num) is highlighted.
+
+*/
+
+{
+ int i,j;
+ unsigned char *ptr;
+ unsigned long block_num,entry_num;
+
+ ptr=type_data.u.buffer;
+ show_pad_info.line=0;show_pad_info.max_line=-1;
+
+ wmove (show_pad,0,0);
+ for (i=0,entry_num=0;i<file_system_info.super_block.s_blocks_per_group/8;i++,ptr++) {
+ for (j=1;j<=128;j*=2) { /* j contains the and bit mask */
+ if (entry_num==block_bitmap_info.entry_num) { /* Highlight the current entry */
+ wattrset (show_pad,A_REVERSE);
+ show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines/2;
+ }
+
+ if ((*ptr) & j) /* Apply the mask */
+ wprintw (show_pad,"1");
+ else
+ wprintw (show_pad,"0");
+
+ if (entry_num==block_bitmap_info.entry_num)
+ wattrset (show_pad,A_NORMAL);
+
+ entry_num++; /* Pass to the next entry */
+ }
+ wprintw (show_pad," ");
+ if (i%8==7) { /* Display 8 groups in a row */
+ wprintw (show_pad,"\n");
+ show_pad_info.max_line++;
+ }
+ }
+
+ refresh_show_pad ();
+ show_info (); /* Show the usual information */
+
+ /* Show the group number */
+ wmove (show_win,1,0);
+ wprintw (show_win,"Block bitmap of block group %ld\n",block_bitmap_info.group_num);
+ /* Show the block number */
+
+ block_num=block_bitmap_info.entry_num+block_bitmap_info.group_num*file_system_info.super_block.s_blocks_per_group;
+ block_num+=file_system_info.super_block.s_first_data_block;
+
+ wprintw (show_win,"Status of block %ld - ",block_num); /* and the allocation status */
+ ptr=type_data.u.buffer+block_bitmap_info.entry_num/8;
+ j=1;
+ for (i=block_bitmap_info.entry_num % 8;i>0;i--)
+ j*=2;
+ if ((*ptr) & j)
+ wprintw (show_win,"Allocated\n");
+ else
+ wprintw (show_win,"Free\n");
+ refresh_show_win ();
+}
diff --git a/ext2ed/dir_com.c b/ext2ed/dir_com.c
new file mode 100644
index 00000000..e1471fbc
--- /dev/null
+++ b/ext2ed/dir_com.c
@@ -0,0 +1,675 @@
+/*
+
+/usr/src/ext2ed/dir_com.c
+
+A part of the extended file system 2 disk editor.
+
+--------------------
+Handles directories.
+--------------------
+
+This file contains the codes which allows the user to handle directories.
+
+Most of the functions use the global variable file_info (along with the special directory fields there) to save
+information and pass it between them.
+
+Since a directory is just a big file which is composed of directory entries, you will find that
+the functions here are a superset of those in the file_com.c source.
+
+We assume that the user reached here using the dir command of the inode type and not by using settype dir, so
+that init_dir_info is indeed called to gather the required information.
+
+type_data is not changed ! It still contains the inode of the file - We handle the directory in our own
+variables, so that settype ext2_inode will "go back" to the inode of this directory.
+
+First written on: April 28 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+char name_search [80];
+long entry_num_search;
+
+int init_dir_info (struct struct_file_info *info_ptr)
+
+/*
+
+This function is called by the inode of the directory when the user issues the dir command from the inode.
+It is used to gather information about the inode and to reset some variables which we need in order to handle
+directories.
+
+*/
+
+{
+ struct ext2_inode *ptr;
+
+ ptr=&type_data.u.t_ext2_inode; /* type_data contains the inode */
+
+ info_ptr->inode_ptr=ptr;
+ info_ptr->inode_offset=device_offset; /* device offset contains the inode's offset */
+
+ /* Reset the current position to the start */
+
+ info_ptr->global_block_num=ptr->i_block [0];
+ info_ptr->global_block_offset=ptr->i_block [0]*file_system_info.block_size;
+ info_ptr->block_num=0;
+ info_ptr->file_offset=0;
+ /* Set the size of the directory */
+
+ info_ptr->blocks_count=(ptr->i_size+file_system_info.block_size-1)/file_system_info.block_size;
+ info_ptr->file_length=ptr->i_size;
+
+ info_ptr->level=0; /* We start using direct blocks */
+ info_ptr->display=HEX; /* This is not actually used */
+
+ info_ptr->dir_entry_num=0;info_ptr->dir_entries_count=0; /* We'll start at the first directory entry */
+ info_ptr->dir_entry_offset=0;
+
+ /* Find dir_entries_count */
+
+ info_ptr->dir_entries_count=count_dir_entries (); /* Set the total number of entries */
+
+ return (1);
+}
+
+struct struct_file_info search_dir_entries (int (*action) (struct struct_file_info *info),int *status)
+
+/*
+ This is the main function in this source file. Various actions are implemented using this basic function.
+
+ This routine runs on all directory entries in the current directory.
+ For each entry, action is called. We'll act according to the return code of action:
+
+ ABORT - Current dir entry is returned.
+ CONTINUE - Continue searching.
+ FOUND - Current dir entry is returned.
+
+ If the last entry is reached, it is returned, along with an ABORT status.
+
+ status is updated to the returned code of action.
+*/
+
+{
+ struct struct_file_info info; /* Temporary variables used to */
+ struct ext2_dir_entry *dir_entry_ptr; /* contain the current search entries */
+
+ int return_code;
+
+ info=first_file_info; /* Start from the first entry - Read it */
+ low_read (info.buffer,file_system_info.block_size,info.global_block_offset);
+ dir_entry_ptr=(struct ext2_dir_entry *) (info.buffer+info.dir_entry_offset);
+
+ while (info.file_offset < info.file_length) { /* While we haven't reached the end */
+
+ *status=return_code=action (&info); /* Call the client function to test */
+ /* the current entry */
+ if (return_code==ABORT || return_code==FOUND)
+ return (info); /* Stop, if so asked */
+
+ /* Pass to the next entry */
+
+ dir_entry_ptr=(struct ext2_dir_entry *) (info.buffer+info.dir_entry_offset);
+
+ info.dir_entry_num++;
+ info.dir_entry_offset+=dir_entry_ptr->rec_len;
+ info.file_offset+=dir_entry_ptr->rec_len;
+
+ if (info.file_offset >= info.file_length) break;
+
+ if (info.dir_entry_offset >= file_system_info.block_size) { /* We crossed a block boundary */
+ /* Find the next block, */
+ info.block_num++;
+ info.global_block_num=file_block_to_global_block (info.block_num,&info);
+ info.global_block_offset=info.global_block_num*file_system_info.block_size;
+ info.file_offset=info.block_num*file_system_info.block_size;
+ info.dir_entry_offset=0;
+ /* read it and update the pointer */
+
+ low_read (info.buffer,file_system_info.block_size,info.global_block_offset);
+ dir_entry_ptr=(struct ext2_dir_entry *) (info.buffer+info.dir_entry_offset);
+
+ }
+
+ }
+
+ *status=ABORT;return (info); /* There was no match */
+}
+
+long count_dir_entries (void)
+
+/*
+
+This function counts the number of entries in the directory. We just call search_dir_entries till the end.
+The client function is action_count, which just tell search_dir_entries to continue.
+
+*/
+
+{
+ int status;
+
+ return (search_dir_entries (&action_count,&status).dir_entry_num);
+}
+
+int action_count (struct struct_file_info *info)
+
+/*
+
+Used by count_dir_entries above - This function is called by search_dir_entries, and it tells it to continue
+searching, until we get to the last entry.
+
+*/
+
+{
+ return (CONTINUE); /* Just continue searching */
+}
+
+void type_dir___cd (char *command_line)
+
+/*
+ Changes to a directory, relative to the current directory.
+
+ This is a complicated operation, so I would repeat here the explanation from the design and
+ implementation document.
+
+1. The path is checked that it is not an absolute path (from /). If it is, we let the general cd to do the job by
+ calling directly type_ext2___cd.
+
+2. The path is divided into the nearest path and the rest of the path. For example, cd 1/2/3/4 is divided into
+ 1 and into 2/3/4.
+
+3. It is the first part of the path that we need to search for in the current directory. We search for it using
+ search_dir_entries, which accepts the action_name function as the client function.
+
+4. search_dir_entries will scan the entire entries and will call our action_name function for each entry.
+ In action_name, the required name will be checked against the name of the current entry, and FOUND will be
+ returned when a match occurs.
+
+5. If the required entry is found, we dispatch a remember command to insert the current inode (remember that
+ type_data is still intact and contains the inode of the current directory) into the object memory.
+ This is required to easily support symbolic links - If we find later that the inode pointed by the entry is
+ actually a symbolic link, we'll need to return to this point, and the above inode doesn't have (and can't have,
+ because of hard links) the information necessary to "move back".
+
+6. We then dispatch a followinode command to reach the inode pointed by the required entry. This command will
+ automatically change the type to ext2_inode - We are now at an inode, and all the inode commands are available.
+
+7. We check the inode's type to see if it is a directory. If it is, we dispatch a dir command to "enter the directory",
+ and recursively call ourself (The type is dir again) by dispatching a cd command, with the rest of the path
+ as an argument.
+
+8. If the inode's type is a symbolic link (only fast symbolic link were meanwhile implemented. I guess this is
+ typically the case.), we note the path it is pointing at, the saved inode is recalled, we dispatch dir to
+ get back to the original directory, and we call ourself again with the link path/rest of the path argument.
+
+9. In any other case, we just stop at the resulting inode.
+
+*/
+
+{
+ int status;
+ char *ptr,full_dir_name [500],dir_name [500],temp [500],temp2 [500];
+ struct struct_file_info info;
+ struct ext2_dir_entry *dir_entry_ptr;
+
+ dir_entry_ptr=(struct ext2_dir_entry *) (file_info.buffer+file_info.dir_entry_offset);
+
+ ptr=parse_word (command_line,dir_name);
+
+ if (*ptr==0) { /* cd alone will enter the highlighted directory */
+ strncpy (full_dir_name,dir_entry_ptr->name,dir_entry_ptr->name_len);
+ full_dir_name [dir_entry_ptr->name_len]=0;
+ }
+ else
+ ptr=parse_word (ptr,full_dir_name);
+
+ ptr=strchr (full_dir_name,'/');
+
+ if (ptr==full_dir_name) { /* Pathname is from root - Let the general cd do the job */
+ sprintf (temp,"cd %s",full_dir_name);type_ext2___cd (temp);return;
+ }
+
+ if (ptr==NULL) {
+ strcpy (dir_name,full_dir_name);
+ full_dir_name [0]=0;
+ }
+
+ else {
+ strncpy (dir_name,full_dir_name,ptr-full_dir_name);
+ dir_name [ptr-full_dir_name]=0;
+ strcpy (full_dir_name,++ptr);
+ }
+ /* dir_name contains the current entry, while */
+ /* full_dir_name contains the rest */
+
+ strcpy (name_search,dir_name); /* name_search is used to hold the required entry name */
+
+ if (dir_entry_ptr->name_len != strlen (dir_name) ||
+ strncmp (dir_name,dir_entry_ptr->name,dir_entry_ptr->name_len)!=0)
+ info=search_dir_entries (&action_name,&status); /* Search for the entry. Answer in info. */
+ else {
+ status=FOUND;info=file_info;
+ }
+
+ if (status==FOUND) { /* If found */
+ file_info=info; /* Switch to it, by setting the global file_info */
+ dispatch ("remember internal_variable"); /* Move the inode into the objects memory */
+
+ dispatch ("followinode"); /* Go to the inode pointed by this directory entry */
+
+ if (S_ISLNK (type_data.u.t_ext2_inode.i_mode)) {/* Symbolic link ? */
+
+ if (type_data.u.t_ext2_inode.i_size > 60) { /* I'm lazy, I guess :-) */
+ wprintw (command_win,"Error - Sorry, Only fast symbolic link following is currently supported\n");
+ refresh_command_win ();
+ return;
+ }
+ /* Get the pointed name and append the previous path */
+
+ strcpy (temp2,(unsigned char *) &type_data.u.t_ext2_inode.i_block);
+ strcat (temp2,"/");
+ strcat (temp2,full_dir_name);
+
+ dispatch ("recall internal_variable"); /* Return to the original inode */
+ dispatch ("dir"); /* and to the directory */
+
+ sprintf (temp,"cd %s",temp2); /* And continue from there by dispatching a cd command */
+ dispatch (temp); /* (which can call ourself or the general cd) */
+
+ return;
+ }
+
+ if (S_ISDIR (type_data.u.t_ext2_inode.i_mode)) { /* Is it an inode of a directory ? */
+
+ dispatch ("dir"); /* Yes - Pass to the pointed directory */
+
+ if (full_dir_name [0] != 0) { /* And call ourself with the rest of the pathname */
+ sprintf (temp,"cd %s",full_dir_name);
+ dispatch (temp);
+ }
+
+ return;
+ }
+
+ else { /* If we can't continue from here, we'll just stop */
+ wprintw (command_win,"Can\'t continue - Stopping at last inode\n");refresh_command_win ();
+ return;
+ }
+ }
+
+ wprintw (command_win,"Error - Directory entry %s not found.\n",dir_name); /* Hmm, an invalid path somewhere */
+ refresh_command_win ();
+}
+
+int action_name (struct struct_file_info *info)
+
+/*
+
+Compares the current search entry name (somewhere inside info) with the required name (in name_search).
+Returns FOUND if found, or CONTINUE if not found.
+
+*/
+
+{
+ struct ext2_dir_entry *dir_entry_ptr;
+
+ dir_entry_ptr=(struct ext2_dir_entry *) (info->buffer+info->dir_entry_offset);
+
+ if (dir_entry_ptr->name_len != strlen (name_search))
+ return (CONTINUE);
+
+ if (strncmp (dir_entry_ptr->name,name_search,dir_entry_ptr->name_len)==0)
+ return (FOUND);
+
+ return (CONTINUE);
+}
+
+void type_dir___entry (char *command_line)
+
+/*
+
+Selects a directory entry according to its number.
+search_dir_entries is used along with action_entry_num, in the same fashion as the previous usage of search_dir_entries.
+
+*/
+
+{
+ int status;
+ struct struct_file_info info;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Argument_not_specified\n");wrefresh (command_win);
+ return;
+ }
+ ptr=parse_word (ptr,buffer);
+ entry_num_search=atol (buffer);
+
+ if (entry_num_search < 0 || entry_num_search >= file_info.dir_entries_count) {
+ wprintw (command_win,"Error - Entry number out of range\n");wrefresh (command_win);
+ return;
+ }
+
+ info=search_dir_entries (&action_entry_num,&status);
+ if (status==FOUND) {
+ file_info=info;
+ dispatch ("show");
+ return;
+ }
+#ifdef DEBUG
+ internal_error ("dir_com","type_dir___entry","According to our gathered data, we should have found this entry");
+#endif
+}
+
+int action_entry_num (struct struct_file_info *info)
+
+/*
+
+Used by the above function. Just compares the current number (in info) with the required one.
+
+*/
+
+{
+ if (info->dir_entry_num == entry_num_search)
+ return (FOUND);
+
+ return (CONTINUE);
+}
+
+void type_dir___followinode (char *command_line)
+
+/*
+
+Here we pass to the inode pointed by the current entry.
+It involves computing the device offset of the inode and using directly the setoffset and settype commands.
+
+*/
+{
+ long inode_offset;
+ char buffer [80];
+
+ struct ext2_dir_entry *dir_entry_ptr;
+
+ low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset);
+ dir_entry_ptr=(struct ext2_dir_entry *) (file_info.buffer+file_info.dir_entry_offset);
+
+ inode_offset=inode_num_to_inode_offset (dir_entry_ptr->inode); /* Compute the inode's offset */
+ sprintf (buffer,"setoffset %ld",inode_offset);dispatch (buffer); /* Move to it */
+ sprintf (buffer,"settype ext2_inode");dispatch (buffer); /* and set the type to an inode */
+}
+
+void type_dir___inode (char *command_line)
+
+/*
+
+Returns to the parent inode of the current directory.
+This is trivial, as we type_data is still intact and contains the parent inode !
+
+*/
+
+{
+ dispatch ("settype ext2_inode");
+}
+
+
+void type_dir___show (char *command_line)
+
+/*
+
+We use search_dir_entries to run on all the entries. Each time, action_show will be called to show one entry.
+
+*/
+
+{
+ int status;
+
+ wmove (show_pad,0,0);
+ show_pad_info.max_line=-1;
+
+ search_dir_entries (&action_show,&status);
+ show_pad_info.line=file_info.dir_entry_num-show_pad_info.display_lines/2;
+ refresh_show_pad ();
+ show_dir_status ();
+}
+
+int action_show (struct struct_file_info *info)
+
+/*
+
+Show the current search entry (info) in one line. If the entry happens to be the current edited entry, it is highlighted.
+
+*/
+
+{
+ unsigned char temp [80];
+ struct ext2_dir_entry *dir_entry_ptr;
+
+ dir_entry_ptr=(struct ext2_dir_entry *) (info->buffer+info->dir_entry_offset);
+
+ if (info->dir_entry_num == file_info.dir_entry_num) /* Highlight the current entry */
+ wattrset (show_pad,A_REVERSE);
+
+ strncpy (temp,dir_entry_ptr->name,dir_entry_ptr->name_len); /* The name is not terminated */
+ temp [dir_entry_ptr->name_len]=0;
+ if (dir_entry_ptr->name_len > (COLS - 55) && COLS > 55)
+ temp [COLS-55]=0;
+ wprintw (show_pad,"inode = %-8lu rec_len = %-4lu name_len = %-3lu name = %s\n", /* Display the various fields */
+ dir_entry_ptr->inode,dir_entry_ptr->rec_len,dir_entry_ptr->name_len,temp);
+
+ show_pad_info.max_line++;
+
+ if (info->dir_entry_num == file_info.dir_entry_num)
+ wattrset (show_pad,A_NORMAL);
+
+ return (CONTINUE); /* And pass to the next */
+}
+
+void type_dir___next (char *command_line)
+
+/*
+
+This function moves to the next directory entry. It just uses the current information and the entry command.
+
+*/
+
+{
+ int offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ offset*=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",file_info.dir_entry_num+offset);dispatch (buffer);
+
+}
+
+void type_dir___prev (char *command_line)
+
+{
+ int offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ offset*=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",file_info.dir_entry_num-offset);dispatch (buffer);
+}
+
+void show_dir_status (void)
+
+/*
+
+Various statistics about the directory.
+
+*/
+
+{
+ long inode_num;
+
+ wmove (show_win,0,0);
+ wprintw (show_win,"Directory listing. Block %ld. ",file_info.global_block_num);
+ wprintw (show_win,"Directory entry %ld of %ld.\n",file_info.dir_entry_num,file_info.dir_entries_count-1);
+ wprintw (show_win,"Directory Offset %ld of %ld. ",file_info.file_offset,file_info.file_length-1);
+
+ inode_num=inode_offset_to_inode_num (file_info.inode_offset);
+ wprintw (show_win,"File inode %ld. Indirection level %ld.\n",inode_num,file_info.level);
+
+ refresh_show_win ();
+}
+
+void type_dir___remember (char *command_line)
+
+/*
+
+This is overrided here because we don't remember a directory - It is too complicated. Instead, we remember the
+inode of the current directory.
+
+*/
+
+{
+ int found=0;
+ long entry_num;
+ char *ptr,buffer [80];
+ struct struct_descriptor *descriptor_ptr;
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Argument not specified\n");wrefresh (command_win);
+ return;
+ }
+
+ ptr=parse_word (ptr,buffer);
+
+ entry_num=remember_lifo.entries_count++;
+ if (entry_num>REMEMBER_COUNT-1) {
+ entry_num=0;
+ remember_lifo.entries_count--;
+ }
+
+ descriptor_ptr=first_type;
+ while (descriptor_ptr!=NULL && !found) {
+ if (strcmp (descriptor_ptr->name,"ext2_inode")==0)
+ found=1;
+ else
+ descriptor_ptr=descriptor_ptr->next;
+ }
+
+
+ remember_lifo.offset [entry_num]=device_offset;
+ remember_lifo.type [entry_num]=descriptor_ptr;
+ strcpy (remember_lifo.name [entry_num],buffer);
+
+ wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",descriptor_ptr->name,device_offset,buffer);
+ wrefresh (command_win);
+}
+
+void type_dir___set (char *command_line)
+
+/*
+
+Since the dir object doesn't have variables, we provide the impression that it has here. ext2_dir_entry was not used
+because it is of variable length.
+
+*/
+
+{
+ int found=0;
+ unsigned char *ptr,buffer [80],variable [80],value [80],temp [80];
+ struct ext2_dir_entry *dir_entry_ptr;
+
+ dir_entry_ptr=(struct ext2_dir_entry *) (file_info.buffer+file_info.dir_entry_offset);
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Missing arguments\n");refresh_command_win ();
+ return;
+ }
+ parse_word (ptr,buffer);
+ ptr=strchr (buffer,'=');
+ if (ptr==NULL) {
+ wprintw (command_win,"Error - Bad syntax\n");refresh_command_win ();return;
+ }
+ strncpy (variable,buffer,ptr-buffer);variable [ptr-buffer]=0;
+ strcpy (value,++ptr);
+
+ if (strcasecmp ("inode",variable)==0) {
+ found=1;
+ dir_entry_ptr->inode=atol (value);
+ wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->inode);refresh_command_win ();
+
+ }
+
+ if (strcasecmp ("rec_len",variable)==0) {
+ found=1;
+ dir_entry_ptr->rec_len=(unsigned int) atol (value);
+ wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->rec_len);refresh_command_win ();
+
+ }
+
+ if (strcasecmp ("name_len",variable)==0) {
+ found=1;
+ dir_entry_ptr->name_len=(unsigned int) atol (value);
+ wprintw (command_win,"Variable %s set to %lu\n",variable,dir_entry_ptr->name_len);refresh_command_win ();
+
+ }
+
+ if (strcasecmp ("name",variable)==0) {
+ found=1;
+ if (strlen (value) > dir_entry_ptr->name_len) {
+ wprintw (command_win,"Error - Length of name greater then name_len\n");
+ refresh_command_win ();return;
+ }
+ strncpy (dir_entry_ptr->name,value,strlen (value));
+ wprintw (command_win,"Variable %s set to %s\n",variable,value);refresh_command_win ();
+
+ }
+
+ if (found) {
+ wattrset (show_pad,A_REVERSE);
+ strncpy (temp,dir_entry_ptr->name,dir_entry_ptr->name_len);
+ temp [dir_entry_ptr->name_len]=0;
+ wmove (show_pad,file_info.dir_entry_num,0);
+ wprintw (show_pad,"inode = %-8lu rec_len = %-4lu name_len = %-3lu name = %s\n",
+ dir_entry_ptr->inode,dir_entry_ptr->rec_len,dir_entry_ptr->name_len,temp);
+ wattrset (show_pad,A_NORMAL);
+ show_pad_info.line=file_info.dir_entry_num-show_pad_info.display_lines/2;
+ refresh_show_pad ();
+ show_dir_status ();
+ }
+
+ else {
+ wprintw (command_win,"Error - Variable %s not found\n",variable);
+ refresh_command_win ();
+ }
+
+}
+
+void type_dir___writedata (char *command_line)
+
+/*
+
+We need to override this since the data is not in type_data. Instead, we have to write the buffer which corresponds
+to the current block.
+
+*/
+
+{
+ low_write (file_info.buffer,file_system_info.block_size,file_info.global_block_offset);
+ return;
+}
diff --git a/ext2ed/disk.c b/ext2ed/disk.c
new file mode 100644
index 00000000..b754bf34
--- /dev/null
+++ b/ext2ed/disk.c
@@ -0,0 +1,238 @@
+/*
+
+/usr/src/ext2ed/disk.c
+
+A part of the extended file system 2 disk editor.
+
+-------------------------------------------------
+The filesystem's disk activity pass through here.
+-------------------------------------------------
+
+This file is acting as a filter - Before we pass an actual read or write request to the operating system, we
+double check the various permissions and possible errors here.
+
+The major update which needs to be done here is switching to the use of the llseek system call, so that we will
+be able to support ext2 filesystems up to 4 TB. Currently, due to the standard fseek usage, we can't handle
+filesystems bigger than 4 GB. The limit is actually 2 GB because I used long rather than unsigned long long at too
+many places in the program. To conclude - This upgrade needs to be done carefuly; There are many places to change.
+
+First written on: April 9 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "ext2ed.h"
+
+int write_access;
+
+int low_read (unsigned char *buffer,unsigned long length,unsigned long offset)
+
+/*
+
+This function is used when we need to read something from the filesystem.
+
+*/
+
+{
+
+#ifdef DEBUG
+
+ char temp [80];
+
+ if (device_handle==NULL) { /* Check that a device is indeed open */
+ internal_error ("No device opened yet read requested","disk","low_read");
+ return (0);
+ }
+ if (offset > file_system_info.file_system_size) { /* Check that the offset is within limits */
+ sprintf (temp,"Seek offset %ld is out of range",offset);
+ internal_error (temp,"disk","low_read");
+ return (0);
+ }
+
+#endif
+
+ if ( (fseek (device_handle,offset,SEEK_SET))==-1) { /* Seek to the required offset */
+ wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",offset,device_name);
+ refresh_command_win ();
+ return (0);
+ };
+
+ if ( (fread (buffer,1,length,device_handle))==-1) { /* And do the actual reading */
+ wprintw (command_win,"Error - Failed to read from offset %ld in device %s\n",offset,device_name);
+ refresh_command_win ();return (0);
+ };
+
+ return (1);
+}
+
+int low_write (unsigned char *buffer,unsigned long length,unsigned long offset)
+
+/*
+
+This is used to change something in the filesystem.
+write_access is checked to see if we are allowed to do the actual writing.
+As a double safety measure, AllowChanges is rechecked here.
+If logging is enabled, we log the change before writing it to the device.
+
+*/
+{
+ char temp [80];
+
+ if (!write_access) {
+ wprintw (command_win,"Error - Write access not aviable (use enablewrite)\n");
+ return (0);
+ }
+
+#ifdef DEBUG
+
+ if (!AllowChanges) {
+ internal_error ("AllowChanges=0 yet enablewrite succeeded","disk","low_write");
+ return (0);
+ }
+
+ if (device_handle==NULL) {
+ internal_error ("No device opened yet read requested","disk","low_write");
+ return (0);
+ }
+
+ if (offset > file_system_info.file_system_size) {
+ sprintf (temp,"Seek offset %ld is out of range",offset);
+ internal_error (temp,"disk","low_write");
+ return (0);
+ }
+
+#endif
+
+ if (LogChanges)
+ if (!log_changes (buffer,length,offset))
+ return (0);
+
+ if ( (fseek (device_handle,offset,SEEK_SET))==-1) {
+ wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",offset,device_name);
+ refresh_command_win ();return (0);
+ };
+
+
+ if ( (fwrite (buffer,1,length,device_handle))==-1) {
+ wprintw (command_win,"Error - Failed to write to offset %ld in device %s\n",offset,device_name);
+ refresh_command_win ();return (0);
+ };
+
+ wprintw (command_win,"Data written");refresh_command_win ();
+ return (1);
+}
+
+int log_changes (unsigned char *buffer,unsigned long length,unsigned long offset)
+
+/*
+
+Log the change in a primitive form - An hex dump of the data before the change and after the change.
+The hex bytes are converted to text, so that they will be readable with a standard text editor.
+
+*/
+
+{
+ unsigned char *original;
+
+ int i;
+ time_t current_time;
+ FILE *fp;
+
+ if ((fp=fopen (LogFile,"a+"))==NULL) {
+ wprintw (command_win,"Error - Unable to open log file %s\n",LogFile);
+ refresh_command_win ();return (0);
+ };
+
+ current_time=time (NULL);
+
+ fprintf (fp,"\n----- EXT2ED log begin -----\n\n");
+ fprintf (fp,"Time: %s\nDevice: %s\n",ctime ((time_t *) &current_time),device_name);
+ fprintf (fp,"Offset: %lu\nLength: %lu\n",offset,length);
+
+ original=(unsigned char *) malloc (length*sizeof (unsigned char));
+
+ if (original==NULL) {
+ wprintw (command_win,"Fatal error - Can\'t allocate %lu bytes !");
+ refresh_command_win ();fclose (fp);return (0);
+ }
+
+ if (!low_read (original,length,offset)) {
+ fclose (fp);return (0);
+ }
+
+ fprintf (fp,"\nOriginal data:\n\n");
+
+ for (i=0;i<length;i++) {
+ if (i%16==0 && i!=0) fprintf (fp,"\n");
+ fprintf (fp,"%02x ",original [i]);
+ }
+
+ fprintf (fp,"\n\nNew data:\n\n");
+
+ for (i=0;i<length;i++) {
+ if (i%16==0 && i!=0) fprintf (fp,"\n");
+ fprintf (fp,"%02x ",buffer [i]);
+ }
+
+ fprintf (fp,"\n----- EXT2ED log end -----\n");
+
+ fclose (fp);
+ return (1);
+}
+
+int load_type_data (void)
+
+/*
+
+Just read from the current position into type data.
+
+*/
+
+{
+ if (device_handle==NULL) {
+ printf ("Error - No device opened\n");
+ return (0);
+ }
+
+ if (device_offset==-1) {
+ printf ("Error - No offset set\n");
+ return (0);
+ }
+
+ if (low_read (type_data.u.buffer,EXT2_MAX_BLOCK_SIZE,device_offset)==0)
+ return (0);
+
+ if (current_type!=NULL)
+ if (strcmp (current_type->name,"ext2_dir_entry")==0)
+ current_type->length=type_data.u.t_ext2_dir_entry.rec_len;
+
+ return (1);
+}
+
+int write_type_data (void)
+
+{
+ if (device_handle==NULL) {
+ wprintw (command_win,"Error - No device opened\n");
+ refresh_command_win ();
+ return (0);
+ }
+
+ if (device_offset==-1) {
+ wprintw (command_win,"Error - No offset set\n");
+ refresh_command_win ();
+ return (0);
+ }
+
+ if (low_write (type_data.u.buffer,file_system_info.block_size,device_offset)==0)
+ return (0);
+
+ return (1);
+}
+
diff --git a/ext2ed/doc/Ext2fs-overview-0.1.sgml b/ext2ed/doc/Ext2fs-overview-0.1.sgml
new file mode 100644
index 00000000..e1740d46
--- /dev/null
+++ b/ext2ed/doc/Ext2fs-overview-0.1.sgml
@@ -0,0 +1,898 @@
+<!doctype linuxdoc system>
+
+<!-- EXT2 filesystem overview -->
+<!-- First written: August 1 1995 -->
+<!-- Last updated: August 3 1995 -->
+<!-- This document is written Using the Linux documentation project Linuxdoc-SGML DTD -->
+
+<article>
+
+<title>The extended-2 filesystem overview
+<author>Gadi Oxman, tgud@tochnapc2.technion.ac.il
+<date>v0.1, August 3 1995
+<toc>
+
+<!-- Begin of document -->
+
+<sect>Preface
+<p>
+
+This document attempts to present an overview of the internal structure of
+the ext2 filesystem. It was written in summer 95, while I was working on the
+<tt>ext2 filesystem editor project (EXT2ED)</>.
+
+In the process of constructing EXT2ED, I acquired knowledge of the various
+design aspects of the the ext2 filesystem. This document is a result of an
+effort to document this knowledge.
+
+This is only the initial version of this document. It is obviously neither
+error-prone nor complete, but at least it provides a starting point.
+
+In the process of learning the subject, I have used the following sources /
+tools:
+<itemize>
+<item> Experimenting with EXT2ED, as it was developed.
+<item> The ext2 kernel sources:
+ <itemize>
+ <item> The main ext2 include file,
+ <tt>/usr/include/linux/ext2_fs.h</>
+ <item> The contents of the directory <tt>/usr/src/linux/fs/ext2</>.
+ <item> The VFS layer sources (only a bit).
+ </itemize>
+<item> The slides: The Second Extended File System, Current State, Future
+ Development, by <tt>Remy Card</>.
+<item> The slides: Optimisation in File Systems, by <tt>Stephen Tweedie</>.
+<item> The various ext2 utilities.
+</itemize>
+
+<sect>Introduction
+<p>
+
+The <tt>Second Extended File System (Ext2fs)</> is very popular among Linux
+users. If you use Linux, chances are that you are using the ext2 filesystem.
+
+Ext2fs was designed by <tt>Remy Card</> and <tt>Wayne Davison</>. It was
+implemented by <tt>Remy Card</> and was further enhanced by <tt>Stephen
+Tweedie</> and <tt>Theodore Ts'o</>.
+
+The ext2 filesystem is still under development. I will document here
+version 0.5a, which is distributed along with Linux 1.2.x. At this time of
+writing, the most recent version of Linux is 1.3.13, and the version of the
+ext2 kernel source is 0.5b. A lot of fancy enhancements are planned for the
+ext2 filesystem in Linux 1.3, so stay tuned.
+
+<sect>A filesystem - Why do we need it ?
+<p>
+
+I thought that before we dive into the various small details, I'll reserve a
+few minutes for the discussion of filesystems from a general point of view.
+
+A <tt>filesystem</> consists of two word - <tt>file</> and <tt>system</>.
+
+Everyone knows the meaning of the word <tt>file</> - A bunch of data put
+somewhere. where ? This is an important question. I, for example, usually
+throw almost everything into a single drawer, and have difficulties finding
+something later.
+
+This is where the <tt>system</> comes in - Instead of just throwing the data
+to the device, we generalize and construct a <tt>system</> which will
+virtualize for us a nice and ordered structure in which we could arrange our
+data in much the same way as books are arranged in a library. The purpose of
+the filesystem, as I understand it, is to make it easy for us to update and
+maintain our data.
+
+Normally, by <tt>mounting</> filesystems, we just use the nice and logical
+virtual structure. However, the disk knows nothing about that - The device
+driver views the disk as a large continuous paper in which we can write notes
+wherever we wish. It is the task of the filesystem management code to store
+bookkeeping information which will serve the kernel for showing us the nice
+and ordered virtual structure.
+
+In this document, we consider one particular administrative structure - The
+Second Extended Filesystem.
+
+<sect>The Linux VFS layer
+<p>
+
+When Linux was first developed, it supported only one filesystem - The
+<tt>Minix</> filesystem. Today, Linux has the ability to support several
+filesystems concurrently. This was done by the introduction of another layer
+between the kernel and the filesystem code - The Virtual File System (VFS).
+
+The kernel "speaks" with the VFS layer. The VFS layer passes the kernel's
+request to the proper filesystem management code. I haven't learned much of
+the VFS layer as I didn't need it for the construction of EXT2ED so that I
+can't elaborate on it. Just be aware that it exists.
+
+<sect>About blocks and block groups
+<p>
+
+In order to ease management, the ext2 filesystem logically divides the disk
+into small units called <tt>blocks</>. A block is the smallest unit which
+can be allocated. Each block in the filesystem can be <tt>allocated</> or
+<tt>free</>.
+<footnote>
+The Ext2fs source code refers to the concept of <tt>fragments</>, which I
+believe are supposed to be sub-block allocations. As far as I know,
+fragments are currently unsupported in Ext2fs.
+</footnote>
+The block size can be selected to be 1024, 2048 or 4096 bytes when creating
+the filesystem.
+
+Ext2fs groups together a fixed number of sequential blocks into a <tt>group
+block</>. The resulting situation is that the filesystem is managed as a
+series of group blocks. This is done in order to keep related information
+physically close on the disk and to ease the management task. As a result,
+much of the filesystem management reduces to management of a single blocks
+group.
+
+<sect>The view of inodes from the point of view of a blocks group
+<p>
+
+Each file in the filesystem is reserved a special <tt>inode</>. I don't want
+to explain inodes now. Rather, I would like to treat it as another resource,
+much like a <tt>block</> - Each blocks group contains a limited number of
+inode, while any specific inode can be <tt>allocated</> or
+<tt>unallocated</>.
+
+<sect>The group descriptors
+<p>
+
+Each blocks group is accompanied by a <tt>group descriptor</>. The group
+descriptor summarizes some necessary information about the specific group
+block. Follows the definition of the group descriptor, as defined in
+/usr/include/linux/ext2_fs.h:
+
+<tscreen><code>
+struct ext2_group_desc
+{
+ __u32 bg_block_bitmap; /* Blocks bitmap block */
+ __u32 bg_inode_bitmap; /* Inodes bitmap block */
+ __u32 bg_inode_table; /* Inodes table block */
+ __u16 bg_free_blocks_count; /* Free blocks count */
+ __u16 bg_free_inodes_count; /* Free inodes count */
+ __u16 bg_used_dirs_count; /* Directories count */
+ __u16 bg_pad;
+ __u32 bg_reserved[3];
+};
+</code></tscreen>
+
+The last three variables: <tt>bg_free_blocks_count, bg_free_inodes_count and
+bg_used_dirs_count</> provide statistics about the use of the three
+resources in a blocks group - The <tt>blocks</>, the <tt>inodes</> and the
+<tt>directories</>. I believe that they are used by the kernel for balancing
+the load between the various blocks groups.
+
+<tt>bg_block_bitmap</> contains the block number of the <tt>block allocation
+bitmap block</>. This is used to allocate / deallocate each block in the
+specific blocks group.
+
+<tt>bg_inode_bitmap</> is fully analogous to the previous variable - It
+contains the block number of the <tt>inode allocation bitmap block</>, which
+is used to allocate / deallocate each specific inode in the filesystem.
+
+<tt>bg_inode_table</> contains the block number of the start of the
+<tt>inode table of the current blocks group</>. The <tt>inode table</> is
+just the actual inodes which are reserved for the current block.
+
+The block bitmap block, inode bitmap block and the inode table are created
+when the filesystem is created.
+
+The group descriptors are placed one after the other. Together they make the
+<tt>group descriptors table</>.
+
+Each blocks group contains the entire table of group descriptors in its
+second block, right after the superblock. However, only the first copy (in
+group 0) is actually used by the kernel. The other copies are there for
+backup purposes and can be of use if the main copy gets corrupted.
+
+<sect>The block bitmap allocation block
+<p>
+
+Each blocks group contains one special block which is actually a map of the
+entire blocks in the group, with respect to their allocation status. Each
+<tt>bit</> in the block bitmap indicated whether a specific block in the
+group is used or free.
+
+The format is actually quite simple - Just view the entire block as a series
+of bits. For example,
+
+Suppose the block size is 1024 bytes. As such, there is a place for
+1024*8=8192 blocks in a group block. This number is one of the fields in the
+filesystem's <tt>superblock</>, which will be explained later.
+
+<itemize>
+<item> Block 0 in the blocks group is managed by bit 0 of byte 0 in the bitmap
+ block.
+<item> Block 7 in the blocks group is managed by bit 7 of byte 0 in the bitmap
+ block.
+<item> Block 8 in the blocks group is managed by bit 0 of byte 1 in the bitmap
+ block.
+<item> Block 8191 in the blocks group is managed by bit 7 of byte 1023 in the
+ bitmap block.
+</itemize>
+
+A value of "<tt>1</>" in the appropriate bit signals that the block is
+allocated, while a value of "<tt>0</>" signals that the block is
+unallocated.
+
+You will probably notice that typically, all the bits in a byte contain the
+same value, making the byte's value <tt>0</> or <tt>0ffh</>. This is done by
+the kernel on purpose in order to group related data in physically close
+blocks, since the physical device is usually optimized to handle such a close
+relationship.
+
+<sect>The inode allocation bitmap
+<p>
+
+The format of the inode allocation bitmap block is exactly like the format of
+the block allocation bitmap block. The explanation above is valid here, with
+the work <tt>block</> replaced by <tt>inode</>. Typically, there are much less
+inodes then blocks in a blocks group and thus only part of the inode bitmap
+block is used. The number of inodes in a blocks group is another variable
+which is listed in the <tt>superblock</>.
+
+<sect>On the inode and the inode tables
+<p>
+
+An inode is a main resource in the ext2 filesystem. It is used for various
+purposes, but the main two are:
+<itemize>
+<item> Support of files
+<item> Support of directories
+</itemize>
+
+Each file, for example, will allocate one inode from the filesystem
+resources.
+
+An ext2 filesystem has a total number of available inodes which is determined
+while creating the filesystem. When all the inodes are used, for example, you
+will not be able to create an additional file even though there will still
+be free blocks on the filesystem.
+
+Each inode takes up 128 bytes in the filesystem. By default, <tt>mke2fs</>
+reserves an inode for each 4096 bytes of the filesystem space.
+
+The inodes are placed in several tables, each of which contains the same
+number of inodes and is placed at a different blocks group. The goal is to
+place inodes and their related files in the same blocks group because of
+locality arguments.
+
+The number of inodes in a blocks group is available in the superblock variable
+<tt>s_inodes_per_group</>. For example, if there are 2000 inodes per group,
+group 0 will contain the inodes 1-2000, group 2 will contain the inodes
+2001-4000, and so on.
+
+Each inode table is accessed from the group descriptor of the specific
+blocks group which contains the table.
+
+Follows the structure of an inode in Ext2fs:
+
+<tscreen><code>
+struct ext2_inode {
+ __u16 i_mode; /* File mode */
+ __u16 i_uid; /* Owner Uid */
+ __u32 i_size; /* Size in bytes */
+ __u32 i_atime; /* Access time */
+ __u32 i_ctime; /* Creation time */
+ __u32 i_mtime; /* Modification time */
+ __u32 i_dtime; /* Deletion Time */
+ __u16 i_gid; /* Group Id */
+ __u16 i_links_count; /* Links count */
+ __u32 i_blocks; /* Blocks count */
+ __u32 i_flags; /* File flags */
+ union {
+ struct {
+ __u32 l_i_reserved1;
+ } linux1;
+ struct {
+ __u32 h_i_translator;
+ } hurd1;
+ struct {
+ __u32 m_i_reserved1;
+ } masix1;
+ } osd1; /* OS dependent 1 */
+ __u32 i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
+ __u32 i_version; /* File version (for NFS) */
+ __u32 i_file_acl; /* File ACL */
+ __u32 i_dir_acl; /* Directory ACL */
+ __u32 i_faddr; /* Fragment address */
+ union {
+ struct {
+ __u8 l_i_frag; /* Fragment number */
+ __u8 l_i_fsize; /* Fragment size */
+ __u16 i_pad1;
+ __u32 l_i_reserved2[2];
+ } linux2;
+ struct {
+ __u8 h_i_frag; /* Fragment number */
+ __u8 h_i_fsize; /* Fragment size */
+ __u16 h_i_mode_high;
+ __u16 h_i_uid_high;
+ __u16 h_i_gid_high;
+ __u32 h_i_author;
+ } hurd2;
+ struct {
+ __u8 m_i_frag; /* Fragment number */
+ __u8 m_i_fsize; /* Fragment size */
+ __u16 m_pad1;
+ __u32 m_i_reserved2[2];
+ } masix2;
+ } osd2; /* OS dependent 2 */
+};
+</code></tscreen>
+
+<sect1>The allocated blocks
+<p>
+
+The basic functionality of an inode is to group together a series of
+allocated blocks. There is no limitation on the allocated blocks - Each
+block can be allocated to each inode. Nevertheless, block allocation will
+usually be done in series to take advantage of the locality principle.
+
+The inode is not always used in that way. I will now explain the allocation
+of blocks, assuming that the current inode type indeed refers to a list of
+allocated blocks.
+
+It was found experimently that many of the files in the filesystem are
+actually quite small. To take advantage of this effect, the kernel provides
+storage of up to 12 block numbers in the inode itself. Those blocks are
+called <tt>direct blocks</>. The advantage is that once the kernel has the
+inode, it can directly access the file's blocks, without an additional disk
+access. Those 12 blocks are directly specified in the variables
+<tt>i_block[0] to i_block[11]</>.
+
+<tt>i_block[12]</> is the <tt>indirect block</> - The block pointed by
+i_block[12] will <tt>not</> be a data block. Rather, it will just contain a
+list of direct blocks. For example, if the block size is 1024 bytes, since
+each block number is 4 bytes long, there will be place for 256 indirect
+blocks. That is, block 13 till block 268 in the file will be accessed by the
+<tt>indirect block</> method. The penalty in this case, compared to the
+direct blocks case, is that an additional access to the device is needed -
+We need <tt>two</> accesses to reach the required data block.
+
+In much the same way, <tt>i_block[13]</> is the <tt>double indirect block</>
+and <tt>i_block[14]</> is the <tt>triple indirect block</>.
+
+<tt>i_block[13]</> points to a block which contains pointers to indirect
+blocks. Each one of them is handled in the way described above.
+
+In much the same way, the triple indirect block is just an additional level
+of indirection - It will point to a list of double indirect blocks.
+
+<sect1>The i_mode variable
+<p>
+
+The i_mode variable is used to determine the <tt>inode type</> and the
+associated <tt>permissions</>. It is best described by representing it as an
+octal number. Since it is a 16 bit variable, there will be 6 octal digits.
+Those are divided into two parts - The rightmost 4 digits and the leftmost 2
+digits.
+
+<sect2>The rightmost 4 octal digits
+<p>
+
+The rightmost 4 digits are <tt>bit options</> - Each bit has its own
+purpose.
+
+The last 3 digits (Octal digits 0,1 and 2) are just the usual permissions,
+in the known form <tt>rwxrwxrwx</>. Digit 2 refers to the user, digit 1 to
+the group and digit 2 to everyone else. They are used by the kernel to grant
+or deny access to the object presented by this inode.
+<footnote>
+A <tt>smarter</> permissions control is one of the enhancements planned for
+Linux 1.3 - The ACL (Access Control Lists). Actually, from browsing of the
+kernel source, some of the ACL handling is already done.
+</footnote>
+
+Bit number 9 signals that the file (I'll refer to the object presented by
+the inode as file even though it can be a special device, for example) is
+<tt>set VTX</>. I still don't know what is the meaning of "VTX".
+
+Bit number 10 signals that the file is <tt>set group id</> - I don't know
+exactly the meaning of the above either.
+
+Bit number 11 signals that the file is <tt>set user id</>, which means that
+the file will run with an effective user id root.
+
+<sect2>The leftmost two octal digits
+<p>
+
+Note the the leftmost octal digit can only be 0 or 1, since the total number
+of bits is 16.
+
+Those digits, as opposed to the rightmost 4 digits, are not bit mapped
+options. They determine the type of the "file" to which the inode belongs:
+<itemize>
+<item> <tt>01</> - The file is a <tt>FIFO</>.
+<item> <tt>02</> - The file is a <tt>character device</>.
+<item> <tt>04</> - The file is a <tt>directory</>.
+<item> <tt>06</> - The file is a <tt>block device</>.
+<item> <tt>10</> - The file is a <tt>regular file</>.
+<item> <tt>12</> - The file is a <tt>symbolic link</>.
+<item> <tt>14</> - The file is a <tt>socket</>.
+</itemize>
+
+<sect1>Time and date
+<p>
+
+Linux records the last time in which various operations occured with the
+file. The time and date are saved in the standard C library format - The
+number of seconds which passed since 00:00:00 GMT, January 1, 1970. The
+following times are recorded:
+<itemize>
+<item> <tt>i_ctime</> - The time in which the inode was last allocated. In
+ other words, the time in which the file was created.
+<item> <tt>i_mtime</> - The time in which the file was last modified.
+<item> <tt>i_atime</> - The time in which the file was last accessed.
+<item> <tt>i_dtime</> - The time in which the inode was deallocated. In
+ other words, the time in which the file was deleted.
+</itemize>
+
+<sect1>i_size
+<p>
+
+<tt>i_size</> contains information about the size of the object presented by
+the inode. If the inode corresponds to a regular file, this is just the size
+of the file in bytes. In other cases, the interpretation of the variable is
+different.
+
+<sect1>User and group id
+<p>
+
+The user and group id of the file are just saved in the variables
+<tt>i_uid</> and <tt>i_gid</>.
+
+<sect1>Hard links
+<p>
+
+Later, when we'll discuss the implementation of directories, it will be
+explained that each <tt>directory entry</> points to an inode. It is quite
+possible that a <tt>single inode</> will be pointed to from <tt>several</>
+directories. In that case, we say that there exist <tt>hard links</> to the
+file - The file can be accessed from each of the directories.
+
+The kernel keeps track of the number of hard links in the variable
+<tt>i_links_count</>. The variable is set to "1" when first allocating the
+inode, and is incremented with each additional link. Deletion of a file will
+delete the current directory entry and will decrement the number of links.
+Only when this number reaches zero, the inode will be actually deallocated.
+
+The name <tt>hard link</> is used to distinguish between the alias method
+described above, to another alias method called <tt>symbolic linking</>,
+which will be described later.
+
+<sect1>The Ext2fs extended flags
+<p>
+
+The ext2 filesystem associates additional flags with an inode. The extended
+attributes are stored in the variable <tt>i_flags</>. <tt>i_flags</> is a 32
+bit variable. Only the 7 rightmost bits are defined. Of them, only 5 bits
+are used in version 0.5a of the filesystem. Specifically, the
+<tt>undelete</> and the <tt>compress</> features are not implemented, and
+are to be introduced in Linux 1.3 development.
+
+The currently available flags are:
+<itemize>
+<item> bit 0 - Secure deletion.
+
+ When this bit is on, the file's blocks are zeroed when the file is
+ deleted. With this bit off, they will just be left with their
+ original data when the inode is deallocated.
+<item> bit 1 - Undelete.
+
+ This bit is not supported yet. It will be used to provide an
+ <tt>undelete</> feature in future Ext2fs developments.
+<item> bit 2 - Compress file.
+
+ This bit is also not supported. The plan is to offer "compression on
+ the fly" in future releases.
+<item> bit 3 - Synchronous updates.
+
+ With this bit on, the meta-data will be written synchronously to the
+ disk, as if the filesystem was mounted with the "sync" mount option.
+<item> bit 4 - Immutable file.
+
+ When this bit is on, the file will stay as it is - Can not be
+ changed, deleted, renamed, no hard links, etc, before the bit is
+ cleared.
+<item> bit 5 - Append only file.
+
+ With this option active, data will only be appended to the file.
+<item> bit 6 - Do not dump this file.
+
+ I think that this bit is used by the port of dump to linux (ported by
+ <tt>Remy Card</>) to check if the file should not be dumped.
+</itemize>
+
+<sect1>Symbolic links
+<p>
+
+The <tt>hard links</> presented above are just another pointers to the same
+inode. The important aspect is that the inode number is <tt>fixed</> when
+the link is created. This means that the implementation details of the
+filesystem are visible to the user - In a pure abstract usage of the
+filesystem, the user should not care about inodes.
+
+The above causes several limitations:
+<itemize>
+<item> Hard links can be done only in the same filesystem. This is obvious,
+ since a hard link is just an inode number in some directory entry,
+ and the above elements are filesystem specific.
+<item> You can not "replace" the file which is pointed to by the hard link
+ after the link creation. "Replacing" the file in one directory will
+ still leave the original file in the other directory - The
+ "replacement" will not deallocate the original inode, but rather
+ allocate another inode for the new version, and the directory entry
+ at the other place will just point to the old inode number.
+</itemize>
+
+<tt>Symbolic link</>, on the other hand, is analyzed at <tt>run time</>. A
+symbolic link is just a <tt>pathname</> which is accessible from an inode.
+As such, it "speaks" in the language of the abstract filesystem. When the
+kernel reaches a symbolic link, it will <tt>follow it in run time</> using
+its normal way of reaching directories.
+
+As such, symbolic link can be made <tt>across different filesystems</> and a
+replacement of a file with a new version will automatically be active on all
+its symbolic links.
+
+The disadvantage is that hard link doesn't consume space except to a small
+directory entry. Symbolic link, on the other hand, consumes at least an
+inode, and can also consume one block.
+
+When the inode is identified as a symbolic link, the kernel needs to find
+the path to which it points.
+
+<sect2>Fast symbolic links
+<p>
+
+When the pathname contains up to 64 bytes, it can be saved directly in the
+inode, on the <tt>i_block[0] - i_block[15]</> variables, since those are not
+needed in that case. This is called <tt>fast</> symbolic link. It is fast
+because the pathname resolution can be done using the inode itself, without
+accessing additional blocks. It is also economical, since it allocates only
+an inode. The length of the pathname is stored in the <tt>i_size</>
+variable.
+
+<sect2>Slow symbolic links
+<p>
+
+Starting from 65 bytes, additional block is allocated (by the use of
+<tt>i_block[0]</>) and the pathname is stored in it. It is called slow
+because the kernel needs to read additional block to resolve the pathname.
+The length is again saved in <tt>i_size</>.
+
+<sect1>i_version
+<p>
+
+<tt>i_version</> is used with regard to Network File System. I don't know
+its exact use.
+
+<sect1>Reserved variables
+<p>
+
+As far as I know, the variables which are connected to ACL and fragments
+are not currently used. They will be supported in future versions.
+
+Ext2fs is being ported to other operating systems. As far as I know,
+at least in linux, the os dependent variables are also not used.
+
+<sect1>Special reserved inodes
+<p>
+
+The first ten inodes on the filesystem are special inodes:
+<itemize>
+<item> Inode 1 is the <tt>bad blocks inode</> - I believe that its data
+ blocks contain a list of the bad blocks in the filesystem, which
+ should not be allocated.
+<item> Inode 2 is the <tt>root inode</> - The inode of the root directory.
+ It is the starting point for reaching a known path in the filesystem.
+<item> Inode 3 is the <tt>acl index inode</>. Access control lists are
+ currently not supported by the ext2 filesystem, so I believe this
+ inode is not used.
+<item> Inode 4 is the <tt>acl data inode</>. Of course, the above applies
+ here too.
+<item> Inode 5 is the <tt>boot loader inode</>. I don't know its
+ usage.
+<item> Inode 6 is the <tt>undelete directory inode</>. It is also a
+ foundation for future enhancements, and is currently not used.
+<item> Inodes 7-10 are <tt>reserved</> and currently not used.
+</itemize>
+
+<sect>Directories
+<p>
+
+A directory is implemented in the same way as files are implemented (with
+the direct blocks, indirect blocks, etc) - It is just a file which is
+formatted with a special format - A list of directory entries.
+
+Follows the definition of a directory entry:
+
+<tscreen><code>
+struct ext2_dir_entry {
+ __u32 inode; /* Inode number */
+ __u16 rec_len; /* Directory entry length */
+ __u16 name_len; /* Name length */
+ char name[EXT2_NAME_LEN]; /* File name */
+};
+</code></tscreen>
+
+Ext2fs supports file names of varying lengths, up to 255 bytes. The
+<tt>name</> field above just contains the file name. Note that it is
+<tt>not zero terminated</>; Instead, the variable <tt>name_len</> contains
+the length of the file name.
+
+The variable <tt>rec_len</> is provided because the directory entries are
+padded with zeroes so that the next entry will be in an offset which is
+a multiplition of 4. The resulting directory entry size is stored in
+<tt>rec_len</>. If the directory entry is the last in the block, it is
+padded with zeroes till the end of the block, and rec_len is updated
+accordingly.
+
+The <tt>inode</> variable points to the inode of the above file.
+
+Deletion of directory entries is done by appending of the deleted entry
+space to the previous (or next, I am not sure) entry.
+
+<sect>The superblock
+<p>
+
+The <tt>superblock</> is a block which contains information which describes
+the state of the internal filesystem.
+
+The superblock is located at the <tt>fixed offset 1024</> in the device. Its
+length is 1024 bytes also.
+
+The superblock, like the group descriptors, is copied on each blocks group
+boundary for backup purposes. However, only the main copy is used by the
+kernel.
+
+The superblock contain three types of information:
+<itemize>
+<item> Filesystem parameters which are fixed and which were determined when
+ this specific filesystem was created. Some of those parameters can
+ be different in different installations of the ext2 filesystem, but
+ can not be changed once the filesystem was created.
+<item> Filesystem parameters which are tunable - Can always be changed.
+<item> Information about the current filesystem state.
+</itemize>
+
+Follows the superblock definition:
+
+<tscreen><code>
+struct ext2_super_block {
+ __u32 s_inodes_count; /* Inodes count */
+ __u32 s_blocks_count; /* Blocks count */
+ __u32 s_r_blocks_count; /* Reserved blocks count */
+ __u32 s_free_blocks_count; /* Free blocks count */
+ __u32 s_free_inodes_count; /* Free inodes count */
+ __u32 s_first_data_block; /* First Data Block */
+ __u32 s_log_block_size; /* Block size */
+ __s32 s_log_frag_size; /* Fragment size */
+ __u32 s_blocks_per_group; /* # Blocks per group */
+ __u32 s_frags_per_group; /* # Fragments per group */
+ __u32 s_inodes_per_group; /* # Inodes per group */
+ __u32 s_mtime; /* Mount time */
+ __u32 s_wtime; /* Write time */
+ __u16 s_mnt_count; /* Mount count */
+ __s16 s_max_mnt_count; /* Maximal mount count */
+ __u16 s_magic; /* Magic signature */
+ __u16 s_state; /* File system state */
+ __u16 s_errors; /* Behaviour when detecting errors */
+ __u16 s_pad;
+ __u32 s_lastcheck; /* time of last check */
+ __u32 s_checkinterval; /* max. time between checks */
+ __u32 s_creator_os; /* OS */
+ __u32 s_rev_level; /* Revision level */
+ __u16 s_def_resuid; /* Default uid for reserved blocks */
+ __u16 s_def_resgid; /* Default gid for reserved blocks */
+ __u32 s_reserved[235]; /* Padding to the end of the block */
+};
+</code></tscreen>
+
+<sect1>superblock identification
+<p>
+
+The ext2 filesystem's superblock is identified by the <tt>s_magic</> field.
+The current ext2 magic number is 0xEF53. I presume that "EF" means "Extended
+Filesystem". In versions of the ext2 filesystem prior to 0.2B, the magic
+number was 0xEF51. Those filesystems are not compatible with the current
+versions; Specifically, the group descriptors definition is different. I
+doubt if there still exists such a installation.
+
+<sect1>Filesystem fixed parameters
+<p>
+
+By using the word <tt>fixed</>, I mean fixed with respect to a particular
+installation. Those variables are usually not fixed with respect to
+different installations.
+
+The <tt>block size</> is determined by using the <tt>s_log_block_size</>
+variable. The block size is 1024*pow (2,s_log_block_size) and should be
+between 1024 and 4096. The available options are 1024, 2048 and 4096.
+
+<tt>s_inodes_count</> contains the total number of available inodes.
+
+<tt>s_blocks_count</> contains the total number of available blocks.
+
+<tt>s_first_data_block</> specifies in which of the <tt>device block</> the
+<tt>superblock</> is present. The superblock is always present at the fixed
+offset 1024, but the device block numbering can differ. For example, if the
+block size is 1024, the superblock will be at <tt>block 1</> with respect to
+the device. However, if the block size is 4096, offset 1024 is included in
+<tt>block 0</> of the device, and in that case <tt>s_first_data_block</>
+will contain 0. At least this is how I understood this variable.
+
+<tt>s_blocks_per_group</> contains the number of blocks which are grouped
+together as a blocks group.
+
+<tt>s_inodes_per_group</> contains the number of inodes available in a group
+block. I think that this is always the total number of inodes divided by the
+number of blocks groups.
+
+<tt>s_creator_os</> contains a code number which specifies the operating
+system which created this specific filesystem:
+<itemize>
+<item> <tt>Linux</> :-) is specified by the value <tt>0</>.
+<item> <tt>Hurd</> is specified by the value <tt>1</>.
+<item> <tt>Masix</> is specified by the value <tt>2</>.
+</itemize>
+
+<tt>s_rev_level</> contains the major version of the ext2 filesystem.
+Currently this is always <tt>0</>, as the most recent version is 0.5B. It
+will probably take some time until we reach version 1.0.
+
+As far as I know, fragments (sub-block allocations) are currently not
+supported and hence a block is equal to a fragment. As a result,
+<tt>s_log_frag_size</> and <tt>s_frags_per_group</> are always equal to
+<tt>s_log_block_size</> and <tt>s_blocks_per_group</>, respectively.
+
+<sect1>Ext2fs error handling
+<p>
+
+The ext2 filesystem error handling is based on the following philosophy:
+<enum>
+<item> Identification of problems is done by the kernel code.
+<item> The correction task is left to an external utility, such as
+ <tt>e2fsck by Theodore Ts'o</> for <tt>automatic</> analysis and
+ correction, or perhaps <tt>debugfs by Theodore Ts'o</> and
+ <tt>EXT2ED by myself</>, for <tt>hand</> analysis and correction.
+</enum>
+
+The <tt>s_state</> variable is used by the kernel to pass the identification
+result to third party utilities:
+<itemize>
+<item> <tt>bit 0</> of s_state is reset when the partition is mounted and
+ set when the partition is unmounted. Thus, a value of 0 on an
+ unmounted filesystem means that the filesystem was not unmounted
+ properly - The filesystem is not "clean" and probably contains
+ errors.
+<item> <tt>bit 1</> of s_state is set by the kernel when it detects an
+ error in the filesystem. A value of 0 doesn't mean that there isn't
+ an error in the filesystem, just that the kernel didn't find any.
+</itemize>
+
+The kernel behavior when an error is found is determined by the user tunable
+parameter <tt>s_errors</>:
+<itemize>
+<item> The kernel will ignore the error and continue if <tt>s_errors=1</>.
+<item> The kernel will remount the filesystem in read-only mode if
+ <tt>s_errors=2</>.
+<item> A kernel panic will be issued if <tt>s_errors=3</>.
+</itemize>
+
+The default behavior is to ignore the error.
+
+<sect1>Additional parameters used by e2fsck
+<p>
+
+Of-course, <tt>e2fsck</> will check the filesystem if errors were detected
+or if the filesystem is not clean.
+
+In addition, each time the filesystem is mounted, <tt>s_mnt_count</> is
+incremented. When s_mnt_count reaches <tt>s_max_mnt_count</>, <tt>e2fsck</>
+will force a check on the filesystem even though it may be clean. It will
+then zero s_mnt_count. <tt>s_max_mnt_count</> is a tunable parameter.
+
+E2fsck also records the last time in which the file system was checked in
+the <tt>s_lastcheck</> variable. The user tunable parameter
+<tt>s_checkinterval</> will contain the number of seconds which are allowed
+to pass since <tt>s_lastcheck</> until a check is reforced. A value of
+<tt>0</> disables time-based check.
+
+<sect1>Additional user tunable parameters
+<p>
+
+<tt>s_r_blocks_count</> contains the number of disk blocks which are
+reserved for root, the user whose id number is <tt>s_def_resuid</> and the
+group whose id number is <tt>s_deg_resgid</>. The kernel will refuse to
+allocate those last <tt>s_r_blocks_count</> if the user is not one of the
+above. This is done so that the filesystem will usually not be 100% full,
+since 100% full filesystems can affect various aspects of operation.
+
+<tt>s_def_resuid</> and <tt>s_def_resgid</> contain the id of the user and
+of the group who can use the reserved blocks in addition to root.
+
+<sect1>Filesystem current state
+<p>
+
+<tt>s_free_blocks_count</> contains the current number of free blocks
+in the filesystem.
+
+<tt>s_free_inodes_count</> contains the current number of free inodes in the
+filesystem.
+
+<tt>s_mtime</> contains the time at which the system was last mounted.
+
+<tt>s_wtime</> contains the last time at which something was changed in the
+filesystem.
+
+<sect>Copyright
+<p>
+
+This document contains source code which was taken from the Linux ext2
+kernel source code, mainly from /usr/include/linux/ext2_fs.h. Follows
+the original copyright:
+
+<tscreen><verb>
+/*
+ * linux/include/linux/ext2_fs.h
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/include/linux/minix_fs.h
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+</verb></tscreen>
+
+<sect>Acknowledgments
+<p>
+
+I would like to thank the following people, who were involved in the
+design and implementation of the ext2 filesystem kernel code and support
+utilities:
+<itemize>
+<item> <tt>Remy Card</>
+
+ Who designed, implemented and maintains the ext2 filesystem kernel
+ code, and some of the ext2 utilities. <tt>Remy Card</> is also the
+ author of several helpful slides concerning the ext2 filesystem.
+ Specifically, he is the author of <tt>File Management in the Linux
+ Kernel</> and of <tt>The Second Extended File System - Current
+ State, Future Development</>.
+
+<item> <tt>Wayne Davison</>
+
+ Who designed the ext2 filesystem.
+<item> <tt>Stephen Tweedie</>
+
+ Who helped designing the ext2 filesystem kernel code and wrote the
+ slides <tt>Optimizations in File Systems</>.
+<item> <tt>Theodore Ts'o</>
+
+ Who is the author of several ext2 utilities and of the ext2 library
+ <tt>libext2fs</> (which I didn't use, simply because I didn't know
+ it exists when I started to work on my project).
+</itemize>
+
+Lastly, I would like to thank, of-course, <tt>Linus Torvalds</> and the
+<tt>Linux community</> for providing all of us with such a great operating
+system.
+
+Please contact me in a case of an error report, suggestions, or just about
+anything concerning this document.
+
+Enjoy,
+
+Gadi Oxman &lt;tgud@tochnapc2.technion.ac.il&gt;
+
+Haifa, August 95
+</article> \ No newline at end of file
diff --git a/ext2ed/doc/ext2ed-design-0.1.sgml b/ext2ed/doc/ext2ed-design-0.1.sgml
new file mode 100644
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--- /dev/null
+++ b/ext2ed/doc/ext2ed-design-0.1.sgml
@@ -0,0 +1,2102 @@
+<!doctype linuxdoc system>
+
+<!-- EXT2ED - Project notes -->
+<!-- First written: July 25 1995 -->
+<!-- Last updated: August 3 1995 -->
+<!-- This document is written Using the Linux documentation project Linuxdoc-SGML DTD -->
+
+<article>
+
+<title>EXT2ED - The Extended-2 filesystem editor - Design and implementation
+<author>Programmed by Gadi Oxman, with the guide of Avner Lottem
+<date>v0.1, August 3 1995
+<toc>
+
+<!-- Begin of document -->
+
+<sect>About EXT2ED documentation
+<p>
+
+The EXT2ED documentation consists of three parts:
+<itemize>
+<item> The ext2 filesystem overview.
+<item> The EXT2ED user's guide.
+<item> The EXT2ED design and implementation.
+</itemize>
+
+This document is not the user's guide. If you just intend to use EXT2ED, you
+may not want to read it.
+
+However, if you intend to browse and modify the source code, this document is
+for you.
+
+In any case, If you intend to read this article, I strongly suggest that you
+will be familiar with the material presented in the other two articles as well.
+
+<sect>Preface
+<p>
+
+In this document I will try to explain how EXT2ED is constructed.
+At this time of writing, the initial version is finished and ready
+for distribution; It is fully functional. However, this was not always the
+case.
+
+At first, I didn't know much about Unix, much less about Unix filesystems,
+and even less about Linux and the extended-2 filesystem. While working
+on this project, I gradually acquired knowledge about all of the above
+subjects. I can think of two ways in which I could have made my project:
+<enum>
+<item> The "Engineer" way
+
+ Learn the subject throughly before I get to the programming itself.
+ Then, I could easily see the entire picture and select the best
+ course of action, taking all the factors into account.
+<item> The "Explorer - Progressive" way.
+
+ Jump immediately into the cold water - Start programming and
+ learning the material parallelly.
+</enum>
+
+I guess that the above dilemma is typical and appears all through science and
+technology.
+
+However, I didn't have the luxury of choice when I started my project -
+Linux is a relatively new (and great !) operating system. The extended-2
+filesystem is even newer - Its first release lies somewhere in 1993 - Only
+passed two years until I started working on my project.
+
+The situation I found myself at the beginning was that I didn't have a fully
+detailed document which describes the ext2 filesystem. In fact, I didn't
+have any ext2 document at all. When I asked Avner about documentation, he
+suggested two references:
+<itemize>
+<item> A general Unix book - THE DESIGN OF THE UNIX OPERATING SYSTEM, by
+ Maurice J. Bach.
+<item> The kernel sources.
+</itemize>
+I read the relevant parts of the book before I started my project - It is a
+bit old now, but the principles are still the same. However, I needed
+more than just the principles.
+
+The kernel sources are a rare bonus ! You don't get everyday the full
+sources of the operating system. There is so much that can be learned from
+them, and it is the ultimate source - The exact answer how the kernel
+works is there, with all the fine details. At the first week I started to
+look at random at the relevant parts of the sources. However, it is difficult
+to understand the global picture from direct reading of over one hundred
+page sources. Then, I started to do some programming. I didn't know
+yet what I was looking for, and I started to work on the project like a kid
+who starts to build a large puzzle.
+
+However, this was exactly the interesting part ! It is frustrating to know
+it all from advance - I think that the discovery itself, bit by bit, is the
+key to a true learning and understanding.
+
+Now, in this document, I am trying to present the subject. Even though I
+developed EXT2ED progressively, I now can see the entire subject much
+brighter than I did before, and though I do have the option of presenting it
+only in the "engineer" way. However, I will not do that.
+
+My presentation will be mixed - Sometimes I will present a subject with an
+incremental perspective, and sometimes from a "top down" view. I'll leave
+you to decide if my presentation choice was wise :-)
+
+In addition, you'll notice that the sections tend to get shorter as we get
+closer to the end. The reason is simply that I started to feel that I was
+repeating myself so I decided to present only the new ideas.
+
+<sect>Getting started ...
+<p>
+
+Getting started is almost always the most difficult task. Once you get
+started, things start "running" ...
+
+<sect1>Before the actual programming
+<p>
+
+From mine talking with Avner, I understood that Linux, like any other Unix
+system, provides accesses to the entire disk as though it were a general
+file - Accessing the device. It is surely a nice idea. Avner suggested two
+ways of action:
+<itemize>
+<item> Opening the device like a regular file in the user space.
+<item> Constructing a device driver which will run in the kernel space and
+ provide hooks for the user space program. The advantage is that it
+ will be a part of the kernel, and would be able to use the ext2
+ kernel functions to do some of the work.
+</itemize>
+I chose the first way. I think that the basic reason was simplicity - Learning
+the ext2 filesystem was complicated enough, and adding to it the task of
+learning how to program in the kernel space was too much. I still don't know
+how to program a device driver, and this is perhaps the bad part, but
+concerning the project in a back-perspective, I think that the first way is
+superior to the second; Ironically, because of the very reason I chose it -
+Simplicity. EXT2ED can now run entirely in the user space (which I think is
+a point in favor, because it doesn't require the user to recompile its
+kernel), and the entire hard work is mine, which fitted nicely into the
+learning experience - I didn't use other code to do the job (aside from
+looking at the sources, of-course).
+
+<sect1>Jumping into the cold water
+<p>
+
+I didn't know almost anything of the structure of the ext2 filesystem.
+Reading the sources was not enough - I needed to experiment. However, a tool
+for experiments in the ext2 filesystem was exactly my project ! - Kind of a
+paradox.
+
+I started immediately with constructing a simple <tt>hex editor</> - It would
+open the device as a regular file, provide means of moving inside the
+filesystem with a simple <tt>offset</> method, and just show a
+<tt> hex dump</> of the contents at this point. Programming this was trivially
+simple of-course. At this point, the user-interface didn't matter to me - I
+wanted a fast way to interact. As a result, I chose a simple command line
+parser. Of course, there where no windows at this point.
+
+A hex editor is nice, but is not enough. It indeed enabled me to see each part
+of the filesystem, but the format of the viewed data was difficult to
+analyze. I wanted to see the data in a more intuitive way.
+
+At this point of time, the most helpful file in the sources was the ext2
+main include file - <tt>/usr/include/linux/ext2_fs.h</>. Among its contents
+there were various structures which I assumed they are disk images - Appear
+exactly like that on the disk.
+
+I wanted a <tt>quick</> way to get going. I didn't have the patience to learn
+each of the structures use in the code. Rather, I wanted to see them in action,
+so that I could explore the connections between them - Test my assumptions,
+and reach other assumptions.
+
+So after the <tt>hex editor</>, EXT2ED progressed into a tool which has some
+elements of a compiler. I programmed EXT2ED to <tt>dynamically read the kernel
+ext2 main include file in run time</>, and process the information. The goal
+was to <tt>imply a structure-definition on the current offset at the
+filesystem</>. EXT2ED would then display the structure as a list of its
+variables names and contents, instead of a meaningless hex dump.
+
+The format of the include file is not very complicated - The structures
+are mostly <tt>flat</> - Didn't contain a lot of recursive structure; Only a
+global structure definition, and some variables. There were cases of
+structures inside structures, I treated them in a somewhat non-elegant way - I
+made all the structures flat, and expanded the arrays. As a result, the parser
+was very simple. After all, this was not an exercise in compiling, and I
+wanted to quickly get some results.
+
+To handle the task, I constructed the <tt>struct_descriptor</> structure.
+Each <tt>struct_descriptor instance</> contained information which is needed
+in order to format a block of data according to the C structure contained in
+the kernel source. The information contained:
+<itemize>
+<item> The descriptor name, used to reference to the structure in EXT2ED.
+<item> The name of each variable.
+<item> The relative offset of the each variable in the data block.
+<item> The length, in bytes, of each variable.
+</itemize>
+Since I didn't want to limit the number of structures, I chose a simple
+double linked list to store the information. One variable contained the
+<tt>current structure type</> - A pointer to the relevant
+<tt>struct_descriptor</>.
+
+Now EXT2ED contained basically three command line operations:
+<itemize>
+<item> setdevice
+
+ Used to open a device for reading only. Write access was postponed
+ to a very advanced state in the project, simply because I didn't
+ know a thing of the filesystem structure, and I believed that
+ making actual changes would do nothing but damage :-)
+<item> setoffset
+
+ Used to move in the device.
+<item> settype
+
+ Used to imply a structure definition on the current place.
+<item> show
+
+ Used to display the data. It displayed the data in a simple hex dump
+ if there was no type set, or in a nice formatted way - As a list of
+ the variable contents, if there was.
+</itemize>
+
+Command line analyzing was primitive back then - A simple switch, as far as
+I can remember - Nothing alike the current flow control, but it was enough
+at the time.
+
+At the end, I had something to start working with. It knew to format many
+structures - None of which I understood - and provided me, without too much
+work, something to start with.
+
+<sect>Starting to explore
+<p>
+
+With the above tool in my pocket, I started to explore the ext2 filesystem
+structure. From the brief reading in Bach's book, I got familiar to some
+basic concepts - The <tt>superblock</>, for example. It seems that the
+superblock is an important part of the filesystem. I decided to start
+exploring with that.
+
+I realized that the superblock should be at a fixed location in the
+filesystem - Probably near the beginning. There can be no other way -
+The kernel should start at some place to find it. A brief looking in
+the kernel sources revealed that the superblock is signed by a special
+signature - A <tt>magic number</> - EXT2_SUPER_MAGIC (0xEF53 - EF probably
+stands for Extended Filesystem). I quickly found the superblock at the
+fixed offset 1024 in the filesystem - The <tt>s_magic</> variable in the
+superblock was set exactly to the above value.
+
+It seems that starting with the <tt>superblock</> was a good bet - Just from
+the list of variables, one can learn a lot. I didn't understand all of them
+at the time, but it seemed that the following keywords were repeating themself
+in various variables:
+<itemize>
+<item> block
+<item> inode
+<item> group
+</itemize>
+At this point, I started to explore the block groups. I will not detail here
+the technical design of the ext2 filesystem. I have written a special
+article which explains just that, in the "engineering" way. Please refer to it
+if you feel that you are lacking knowledge in the structure of the ext2
+filesystem.
+
+I was exploring the filesystem in this way for some time, along with reading
+the sources. This lead naturally to the next step.
+
+<sect>Object specific commands
+<p>
+
+What has become clear is that the above way of exploring is not powerful
+enough - I found myself doing various calculations manually in order to pass
+between related structures. I needed to replace some tasks with an automated
+procedure.
+
+In addition, it also became clear that (of-course) each key object in the
+filesystem has its special place in regard to the overall ext2 filesystem
+design, and needs a <tt>fine tuned handling</>. It is at this point that the
+structure definitions <tt>came to life</> - They became <tt>object
+definitions</>, making EXT2ED <tt>object oriented</>.
+
+The actual meaning of the breathtaking words above, is that each structure
+now had a list of <tt>private commands</>, which ended up in
+<tt>calling special fine-tuned C functions</>. This approach was
+found to be very powerful and is <tt>the heart of EXT2ED even now</>.
+
+In order to implement the above concepts, I added the structure
+<tt>struct_commands</>. The role of this structure is to group together a
+group of commands, which can be later assigned to a specific type. Each
+structure had:
+<itemize>
+<item> A list of command names.
+<item> A list of pointers to functions, which binds each command to its
+ special fine-tuned C function.
+</itemize>
+In order to relate a list of commands to a type definition, each
+<tt>struct_descriptor</> structure (explained earlier) was added a private
+<tt>struct_commands</> structure.
+
+Follows the current definitions of <tt>struct_descriptor</> and of
+<tt>struct_command</>:
+<tscreen><code>
+struct struct_descriptor {
+ unsigned long length;
+ unsigned char name [60];
+ unsigned short fields_num;
+ unsigned char field_names [MAX_FIELDS][80];
+ unsigned short field_lengths [MAX_FIELDS];
+ unsigned short field_positions [MAX_FIELDS];
+ struct struct_commands type_commands;
+ struct struct_descriptor *prev,*next;
+};
+
+typedef void (*PF) (char *);
+
+struct struct_commands {
+ int last_command;
+ char *names [MAX_COMMANDS_NUM];
+ char *descriptions [MAX_COMMANDS_NUM];
+ PF callback [MAX_COMMANDS_NUM];
+};
+</code></tscreen>
+
+<sect><label id="flow_control">Program flow control
+<p>
+
+Obviously the above approach lead to a major redesign of EXT2ED. The
+main engine of the resulting design is basically the same even now.
+
+I redesigned the program flow control. Up to now, I analyzed the user command
+line with the simple switch method. Now I used the far superior callback
+method.
+
+I divided the available user commands into two groups:
+<enum>
+<item> General commands.
+<item> Type specific commands.
+</enum>
+As a result, at each point in time, the user was able to enter a
+<tt>general command</>, selectable from a list of general commands which was
+always available, or a <tt>type specific command</>, selectable from a list of
+commands which <tt>changed in time</> according to the current type that the
+user was editing. The special <tt>type specific command</> "knew" how to
+handle the object in the best possible way - It was "fine tuned" for the
+object's place in the ext2 filesystem design.
+
+In order to implement the above idea, I constructed a global variable of
+type <tt>struct_commands</>, which contained the <tt>general commands</>.
+The <tt>type specific commands</> were accessible through the <tt>struct
+descriptors</>, as explained earlier.
+
+The program flow was now done according to the following algorithm:
+<enum>
+<item> Ask the user for a command line.
+<item> Analyze the user command - Separate it into <tt>command</> and
+ <tt>arguments</>.
+<item> Trace the list of known objects to match the command name to a type.
+ If the type is found, call the callback function, with the arguments
+ as a parameter. Then go back to step (1).
+<item> If the command is not type specific, try to find it in the general
+ commands, and call it if found. Go back to step (1).
+<item> If the command is not found, issue a short error message, and return
+ to step (1).
+</enum>
+Note the <tt>order</> of the above steps. In particular, note that a command
+is first assumed to be a type-specific command and only if this fails, a
+general command is searched. The "<tt>side-effect</>" (main effect, actually)
+is that when we have two commands with the <tt>same name</> - One that is a
+type specific command, and one that is a general command, the dispatching
+algorithm will call the <tt>type specific command</>. This allows
+<tt>overriding</> of a command to provide <tt>fine-tuned</> operation.
+For example, the <tt>show</> command is overridden nearly everywhere,
+to accommodate for the different ways in which different objects are displayed,
+in order to provide an intuitive fine-tuned display.
+
+The above is done in the <tt>dispatch</> function, in <tt>main.c</>. Since
+it is a very important function in EXT2ED, and it is relatively short, I will
+list it entirely here. Note that a redesign was made since then - Another
+level was added between the two described, but I'll elaborate more on this
+later. However, the basic structure follows the explanation described above.
+<tscreen><code>
+int dispatch (char *command_line)
+
+{
+ int i,found=0;
+ char command [80];
+
+ parse_word (command_line,command);
+
+ if (strcmp (command,"quit")==0) return (1);
+
+ /* 1. Search for type specific commands FIRST - Allows overriding of a general command */
+
+ if (current_type != NULL)
+ for (i=0;i<=current_type->type_commands.last_command && !found;i++) {
+ if (strcmp (command,current_type->type_commands.names [i])==0) {
+ (*current_type->type_commands.callback [i]) (command_line);
+ found=1;
+ }
+ }
+
+ /* 2. Now search for ext2 filesystem general commands */
+
+ if (!found)
+ for (i=0;i<=ext2_commands.last_command && !found;i++) {
+ if (strcmp (command,ext2_commands.names [i])==0) {
+ (*ext2_commands.callback [i]) (command_line);
+ found=1;
+ }
+ }
+
+
+ /* 3. If not found, search the general commands */
+
+ if (!found)
+ for (i=0;i<=general_commands.last_command && !found;i++) {
+ if (strcmp (command,general_commands.names [i])==0) {
+ (*general_commands.callback [i]) (command_line);
+ found=1;
+ }
+ }
+
+ if (!found) {
+ wprintw (command_win,"Error: Unknown command\n");
+ refresh_command_win ();
+ }
+
+ return (0);
+}
+</code></tscreen>
+
+<sect>Source files in EXT2ED
+<p>
+
+The project was getting large enough to be splitted into several source
+files. I splitted the source as much as I could into self-contained
+source files. The source files consist of the following blocks:
+<itemize>
+<item> <tt>Main include file - ext2ed.h</>
+
+ This file contains the definitions of the various structures,
+ variables and functions used in EXT2ED. It is included by all source
+ files in EXT2ED.
+
+<item> <tt>Main block - main.c</>
+
+ <tt>main.c</> handles the upper level of the program flow control.
+ It contains the <tt>parser</> and the <tt>dispatcher</>. Its task is
+ to ask the user for a required action, and to pass control to other
+ lower level functions in order to do the actual job.
+
+<item> <tt>Initialization - init.c</>
+
+ The init source is responsible for the various initialization
+ actions which need to be done through the program. For example,
+ auto detection of an ext2 filesystem when selecting a device and
+ initialization of the filesystem-specific structures described
+ earlier.
+
+<item> <tt>Disk activity - disk.c</>
+
+ <tt>disk.c</> is handles the lower level interaction with the
+ device. All disk activity is passed through this file - The various
+ functions through the source code request disk actions from the
+ functions in this file. In this way, for example, we can easily block
+ the write access to the device.
+
+<item> <tt>Display output activity - win.c</>
+
+ In a similar way to <tt>disk.c</>, the user-interface functions and
+ most of the interaction with the <tt>ncurses library</> are done
+ here. Nothing will be actually written to a specific window without
+ calling a function from this file.
+
+<item> <tt>Commands available through dispatching - *_com.c </>
+
+ The above file name is generic - Each file which ends with
+ <tt>_com.c</> contains a group of related commands which can be
+ called through <tt>the dispatching function</>.
+
+ Each object typically has its own file. A separate file is also
+ available for the general commands.
+</itemize>
+The entire list of source files available at this time is:
+<itemize>
+<item> blockbitmap_com.c
+<item> dir_com.c
+<item> disk.c
+<item> ext2_com.c
+<item> file_com.c
+<item> general_com.c
+<item> group_com.c
+<item> init.c
+<item> inode_com.c
+<item> inodebitmap_com.c
+<item> main.c
+<item> super_com.c
+<item> win.c
+</itemize>
+
+<sect>User interface
+<p>
+
+The user interface is text-based only and is based on the following
+libraries:
+
+<itemize>
+<item> The <tt>ncurses</> library, developed by <tt>Zeyd Ben-Halim</>.
+<item> The <tt>GNU readline</> library.
+</itemize>
+
+The user interaction is command line based - The user enters a command
+line, which consists of a <tt>command</> and of <tt>arguments</>. This fits
+nicely with the program flow control described earlier - The <tt>command</>
+is used by <tt>dispatch</> to select the right function, and the
+<tt>arguments</> are interpreted by the function itself.
+
+<sect1>The ncurses library
+<p>
+
+The <tt>ncurses</> library enables me to divide the screen into "windows".
+The main advantage is that I treat the "window" in a virtual way, asking
+the ncurses library to "write to a window". However, the ncurses
+library internally buffers the requests, and nothing is actually passed to the
+terminal until an explicit refresh is requested. When the refresh request is
+made, ncurses compares the current terminal state (as known in the last time
+that a refresh was done) with the new to be shown state, and passes to the
+terminal the minimal information required to update the display. As a
+result, the display output is optimized behind the scenes by the
+<tt>ncurses</> library, while I can still treat it in a virtual way.
+
+There are two basic concepts in the <tt>ncurses</> library:
+<itemize>
+<item> A window.
+<item> A pad.
+</itemize>
+A window can be no bigger than the actual terminal size. A pad, however, is
+not limited in its size.
+
+The user screen is divided by EXT2ED into three windows and one pad:
+<itemize>
+<item> Title window.
+<item> Status window.
+<item> Main display pad.
+<item> Command window.
+</itemize>
+
+The <tt>title window</> is static - It just displays the current version
+of EXT2ED.
+
+The user interaction is done in the <tt>command window</>. The user enters a
+<tt>command line</>, feedback is usually displayed there, and then relevant
+data is usually displayed in the main display and in the status window.
+
+The <tt>main display</> is using a <tt>pad</> instead of a window because
+the amount of information which is written to it is not known in advance.
+Therefor, the user treats the main display as a "window" into a bigger
+display and can <tt>scroll vertically</> using the <tt>pgdn</> and <tt>pgup</>
+commands. Although the <tt>pad</> mechanism enables me to use horizontal
+scrolling, I have not utilized this.
+
+When I need to show something to the user, I use the ncurses <tt>wprintw</>
+command. Then an explicit refresh command is required. As explained before,
+the refresh commands is piped through <tt>win.c</>. For example, to update
+the command window, <tt>refresh_command_win ()</> is used.
+
+<sect1>The readline library
+<p>
+
+Avner suggested me to integrate the GNU <tt>readline</> library in my project.
+The <tt>readline</> library is designed specifically for programs which use
+command line interface. It provides a nice package of <tt>command line editing
+tools</> - Inserting, deleting words, and the whole package of editing tools
+which are normally available in the <tt>bash</> shell (Refer to the readline
+documentation for details). In addition, I utilized the <tt>history</>
+feature of the readline library - The entered commands are saved in a
+<tt>command history</>, and can be called later by whatever means that the
+readline package provides. Command completion is also supported - When the
+user enters a partial command name, EXT2ED will provide the readline library
+with the possible completions.
+
+<sect>Possible support of other filesystems
+<p>
+
+The entire ext2 layer is provided through specific objects. Given another
+set of objects, support of other filesystem can be provided using the same
+dispatching mechanism. In order to prepare the surface for this option, I
+added yet another layer to the two-layer structure presented earlier. EXT2ED
+commands now consist of three layers:
+<itemize>
+<item> The general commands.
+<item> The ext2 general commands.
+<item> The ext2 object specific commands.
+</itemize>
+The general commands are provided by the <tt>general_com.c</> source file,
+and are always available. The two other levels are not present when EXT2ED
+loads - They are dynamically added by <tt>init.c</> when EXT2ED detects an
+ext2 filesystem on the device.
+
+The abstraction levels presented above helps to extend EXT2ED to fully
+support a new filesystem, with its own specific type commands.
+
+Even without any source code modification, the user is free to add structure
+definitions in a separate file (specified in the configuration file),
+which will be added to the list of available objects. The added objects will
+consist only of variables, of-course, and will be used through the more
+primitive <tt>setoffset</> and <tt>settype</> commands.
+
+<sect>On the implementation of the various commands
+<p>
+
+This section points out some typical programming style that I used in many
+places at the code.
+
+<sect1>The explicit use of the dispatch function
+<p>
+
+The various commands are reached by the user through the <tt>dispatch</>
+function. This is not surprising. The fact that can be surprising, at least in
+a first look, is that <tt>you'll find the <em>dispatch</> call in many of my
+own functions !</>.
+
+I am in fact using my own implemented functions to construct higher
+level operations. I am heavily using the fact that the dispatching mechanism
+is object oriented ant that the <tt>overriding</> principle takes place and
+selects the proper function to call when several commands with the same name
+are accessible.
+
+Sometimes, however, I call the explicit command directly, without passing
+through <tt>dispatch</>. This is typically done when I want to bypass the
+<tt>overriding</> effect.
+
+<tscreen><verb>
+This is used, for example, in the interaction between the global cd command
+and the dir object specific cd command. You will see there that in order
+to implement the "entire" cd command, the type specific cd command uses both
+a dispatching mechanism to call itself recursively if a relative path is
+used, or a direct call of the general cd handling function if an explicit path
+is used.
+</verb></tscreen>
+
+<sect1>Passing information between handling functions
+<p>
+
+Typically, every source code file which handles one object type has a global
+structure specifically designed for it which is used by most of the
+functions in that file. This is used to pass information between the various
+functions there, and to physically provide the link to other related
+objects, typically for initialization use.
+
+<tscreen><verb>
+For example, in order to edit a file, information about the
+inode is needed - The file command is available only when editing an
+inode. When the file command is issued, the handling function (found,
+according to the source division outlined above, in inode_com.c) will
+store the necessary information about the inode in a specific structure
+of type struct_file_info which will be available for use by the file_com.c
+functions. Only then it will set the type to file. This is also the reason
+that a direct asynchronic set of the object type to a file through a settype
+command will fail - The above data structure will not be initialized
+properly because the user never was at the inode of the file.
+</verb></tscreen>
+
+<sect1>A very simplified overview of a typical command handling function
+<p>
+
+This is a very simplified overview. Detailed information will follow
+where appropriate.
+
+<sect2>The prototype of a typical handling function
+<p>
+
+<enum>
+<item> I chose a unified <tt>naming convention</> for the various object
+ specific commands. It is perhaps best showed with an example:
+
+ The prototype of the handling function of the command <tt>next</> of
+ the type <tt>file</> is:
+ <tscreen><verb>
+ extern void type_file___next (char *command_line);
+ </verb></tscreen>
+
+ For other types and commands, the words <tt>file</> and <tt>next</>
+ should be replaced accordingly.
+
+<item> The ext2 general commands syntax is similar. For example, the ext2
+ general command <tt>super</> results in calling:
+ <tscreen><verb>
+ extern void type_ext2___super (char *command_line);
+ </verb></tscreen>
+ Those functions are available in <tt>ext2_com.c</>.
+<item> The general commands syntax is even simpler - The name of the
+ handling function is exactly the name of the commands. Those
+ functions are available in <tt>general_com.c</>.
+</enum>
+
+<sect2> "Typical" algorithm
+<p>
+
+This section can't of-course provide meaningful information - Each
+command is handled differently, but the following frame is typical:
+<enum>
+<item> Parse command line arguments and analyze them. Return with an error
+ message if the syntax is wrong.
+<item> "Act accordingly", perhaps making use of the global variable available
+ to this type.
+<item> Use some <tt>dispatch / direct </> calls in order to pass control to
+ other lower-level user commands.
+<item> Sometimes <tt>dispatch</> to the object's <tt>show</> command to
+ display the resulting data to the user.
+</enum>
+I told you it is meaningless :-)
+
+<sect>Initialization overview
+<p>
+
+In this section I will discuss some aspects of the various initialization
+routines available in the source file <tt>init.c</>.
+
+<sect1>Upon startup
+<p>
+
+Follows the function <tt>main</>, appearing of-course in <tt>main.c</>:
+<tscreen><code>
+int main (void)
+
+{
+ if (!init ()) return (0); /* Perform some initial initialization */
+ /* Quit if failed */
+
+ parser (); /* Get and parse user commands */
+
+ prepare_to_close (); /* Do some cleanup */
+ printf ("Quitting ...\n");
+ return (1); /* And quit */
+}
+</code></tscreen>
+
+The two initialization functions, which are called by <tt>main</>, are:
+<itemize>
+<item> init
+<item> prepare_to_close
+</itemize>
+
+<sect2>The init function
+<p>
+
+<tt>init</> is called from <tt>main</> upon startup. It initializes the
+following tasks / subsystems:
+<enum>
+<item> Processing of the <tt>user configuration file</>, by using the
+ <tt>process_configuration_file</> function. Failing to complete the
+ configuration file processing is considered a <tt>fatal error</>,
+ and EXT2ED is aborted. I did it this way because the configuration
+ file has some sensitive user options like write access behavior, and
+ I wanted to be sure that the user is aware of them.
+<item> Registration of the <tt>general commands</> through the use of
+ the <tt>add_general_commands</> function.
+<item> Reset of the object memory rotating lifo structure.
+<item> Reset of the device parameters and of the current type.
+<item> Initialization of the windows subsystem - The interface between the
+ ncurses library and EXT2ED, through the use of the <tt>init_windows</>
+ function, available in <tt>win.c</>.
+<item> Initialization of the interface between the readline library and
+ EXT2ED, through <tt>init_readline</>.
+<item> Initialization of the <tt>signals</> subsystem, through
+ <tt>init_signals</>.
+<item> Disabling write access. Write access needs to be explicitly enabled
+ using a user command, to prevent accidental user mistakes.
+</enum>
+When <tt>init</> is finished, it dispatches the <tt>help</> command in order
+to show the available commands to the user. Note that the ext2 layer is still
+not added; It will be added if and when EXT2ED will detect an ext2
+filesystem on a device.
+
+<sect2>The prepare_to_close function
+<p>
+
+The <tt>prepare_to_close</> function reverses some of the actions done
+earlier in EXT2ED and freeing the dynamically allocated memory.
+Specifically, it:
+<enum>
+<item> Closes the open device, if any.
+<item> Removes the first level - Removing the general commands, through
+ the use of <tt>free_user_commands</>, with a pointer to the
+ general_commands structure as a parameter.
+<item> Removes of the second level - Removing the ext2 ext2 general
+ commands, in much the same way.
+<item> Removes of the third level - Removing the objects and the object
+ specific commands, by using <tt>free_struct_descriptors</>.
+<item> Closes the window subsystem, and deattaches EXT2ED from the ncurses
+ library, through the use of the <tt>close_windows</> function,
+ available in <tt>win.c</>.
+</enum>
+
+<sect1> Registration of commands
+<p>
+
+Addition of a user command is done through the <tt>add_user_command</>
+function. The prototype is:
+<tscreen><verb>
+void add_user_command (struct struct_commands *ptr,char *name,char
+*description,PF callback);
+</verb></tscreen>
+The function receives a pointer to a structure of type
+<tt>struct_commands</>, a desired name for the command which will be used by
+the user to identify the command, a short description which is utilized by the
+<tt>help</> subsystem, and a pointer to a C function which will be called if
+<tt>dispatch</> decides that this command was requested.
+
+The <tt>add_user_command</> is a <tt>low level function</> used in the three
+levels to add user commands. For example, addition of the <tt>ext2
+general commands is done by:</>
+<tscreen><code>
+void add_ext2_general_commands (void)
+
+{
+ add_user_command (&ero;ext2_commands,"super","Moves to the superblock of the filesystem",type_ext2___super);
+ add_user_command (&ero;ext2_commands,"group","Moves to the first group descriptor",type_ext2___group);
+ add_user_command (&ero;ext2_commands,"cd","Moves to the directory specified",type_ext2___cd);
+}
+</code></tscreen>
+
+<sect1>Registration of objects
+<p>
+
+Registration of objects is based, as explained earlier, on the "compilation"
+of an external user file, which has a syntax similar to the C language
+<tt>struct</> keyword. The primitive parser I have implemented detects the
+definition of structures, and calls some lower level functions to actually
+register the new detected object. The parser's prototype is:
+<tscreen><verb>
+int set_struct_descriptors (char *file_name)
+</verb></tscreen>
+It opens the given file name, and calls, when appropriate:
+<itemize>
+<item> add_new_descriptor
+<item> add_new_variable
+</itemize>
+<tt>add_new_descriptor</> is a low level function which adds a new descriptor
+to the doubly linked list of the available objects. It will then call
+<tt>fill_type_commands</>, which will add specific commands to the object,
+if the object is known.
+
+<tt>add_new_variable</> will add a new variable of the requested length to the
+specified descriptor.
+
+<sect1>Initialization upon specification of a device
+<p>
+
+When the general command <tt>setdevice</> is used to open a device, some
+initialization sequence takes place, which is intended to determine two
+factors:
+<itemize>
+<item> Are we dealing with an ext2 filesystem ?
+<item> What are the basic filesystem parameters, such as its total size and
+ its block size ?
+</itemize>
+This questions are answered by the <tt>set_file_system_info</>, possibly
+using some <tt>help from the user</>, through the configuration file.
+The answers are placed in the <tt>file_system_info</> structure, which is of
+type <tt>struct_file_system_info</>:
+<tscreen><code>
+struct struct_file_system_info {
+ unsigned long file_system_size;
+ unsigned long super_block_offset;
+ unsigned long first_group_desc_offset;
+ unsigned long groups_count;
+ unsigned long inodes_per_block;
+ unsigned long blocks_per_group; /* The name is misleading; beware */
+ unsigned long no_blocks_in_group;
+ unsigned short block_size;
+ struct ext2_super_block super_block;
+};
+</code></tscreen>
+
+Autodetection of an ext2 filesystem is usually recommended. However, on a damaged
+filesystem I can't assure a success. That's were the user comes in - He can
+<tt>override</> the auto detection procedure and force an ext2 filesystem, by
+selecting the proper options in the configuration file.
+
+If auto detection succeeds, the second question above is automatically
+answered - I get all the information I need from the filesystem itself. In
+any case, default parameters can be supplied in the configuration file and
+the user can select the required behavior.
+
+If we decide to treat the filesystem as an ext2 filesystem, <tt>registration of
+the ext2 specific objects</> is done at this point, by calling the
+<tt>set_struct_descriptors</> outlined earlier, with the name of the file
+which describes the ext2 objects, and is basically based on the ext2 sources
+main include file. At this point, EXT2ED can be fully used by the user.
+
+If we do not register the ext2 specific objects, the user can still provide
+object definitions in a separate file, and will be able to use EXT2ED in a
+<tt>limited form</>, but more sophisticated than a simple hex editor.
+
+<sect>main.c
+<p>
+
+As described earlier, <tt>main.c</> is used as a front-head to the entire
+program. <tt>main.c</> contains the following elements:
+
+<sect1>The main routine
+<p>
+
+The <tt>main</> routine was displayed above. Its task is to pass control to
+the initialization routines and to the parser.
+
+<sect1>The parser
+<p>
+
+The parser consists of the following functions:
+<itemize>
+<item> The <tt>parser</> function, which reads the command line from the
+ user and saves it in readline's history buffer and in the internal
+ last-command buffer.
+<item> The <tt>parse_word</> function, which receives a string and parses
+ the first word from it, ignoring whitespaces, and returns a pointer
+ to the rest of the string.
+<item> The <tt>complete_command</> function, which is used by the readline
+ library for command completion. It scans the available commands at
+ this point and determines the possible completions.
+</itemize>
+
+<sect1>The dispatcher
+<p>
+
+The dispatcher was already explained in the flow control section - section
+<ref id="flow_control">. Its task is to pass control to the proper command
+handling function, based on the command line's command.
+
+<sect1>The self-sanity control
+<p>
+
+This is not fully implemented.
+
+The general idea was to provide a control system which will supervise the
+internal work of EXT2ED. Since I am pretty sure that bugs exist, I have
+double checked myself in a few instances, and issued an <tt>internal
+error</> warning if I reached the conclusion that something is not logical.
+The internal error is reported by the function <tt>internal_error</>,
+available in <tt>main.c</>.
+
+The self sanity check is compiled only if the compile time option
+<tt>DEBUG</> is selected.
+
+<sect>The windows interface
+<p>
+
+Screen handling and interfacing to the <tt>ncurses</> library is done in
+<tt>win.c</>.
+
+<sect1>Initialization
+<p>
+
+Opening of the windows is done in <tt>init_windows</>. In
+<tt>close_windows</>, we just close our windows. The various window lengths
+with an exception to the <tt>show pad</> are defined in the main header file.
+The rest of the display will be used by the <tt>show pad</>.
+
+<sect1>Display output
+<p>
+
+Each actual refreshing of the terminal monitor is done by using the
+appropriate refresh function from this file: <tt>refresh_title_win</>,
+<tt>refresh_show_win</>, <tt>refresh_show_pad</> and
+<tt>refresh_command_win</>.
+
+With the exception of the <tt>show pad</>, each function simply calls the
+<tt>ncurses refresh command</>. In order to provide to <tt>scrolling</> in
+the <tt>show pad</>, some information about its status is constantly updated
+by the various functions which display output in it. <tt>refresh_show_pad</>
+passes this information to <tt>ncurses</> so that the correct part of the pad
+is actually copied to the display.
+
+The above information is saved in a global variable of type <tt>struct
+struct_pad_info</>:
+
+<tscreen><code>
+struct struct_pad_info {
+ int display_lines,display_cols;
+ int line,col;
+ int max_line,max_col;
+ int disable_output;
+};
+</code></tscreen>
+
+<sect1>Screen redraw
+<p>
+
+The <tt>redraw_all</> function will just reopen the windows. This action is
+necessary if the display gets garbled from some reason.
+
+<sect>The disk interface
+<p>
+
+All the disk activity with regard to the filesystem passes through the file
+<tt>disk.c</>. This is done that way to provide additional levels of safety
+concerning the disk access. This way, global decisions considering the disk
+can be easily accomplished. The benefits of this isolation will become even
+clearer in the next sections.
+
+<sect1>Low level functions
+<p>
+
+Read requests are ultimately handled by <tt>low_read</> and write requests
+are handled by <tt>low_write</>. They just receive the length of the data
+block, the offset in the filesystem and a pointer to the buffer and pass the
+request to the <tt>fread</> or <tt>fwrite</> standard library functions.
+
+<sect1>Mounted filesystems
+<p>
+
+EXT2ED design assumes that the edited filesystem is not mounted. Even if
+a <tt>reasonably simple</> way to handle mounted filesystems exists, it is
+probably <tt>too complicated</> :-)
+
+Write access to a mounted filesystem will be denied. Read access can be
+allowed by using a configuration file option. The mount status is determined
+by reading the file /etc/mtab.
+
+<sect1>Write access
+<p>
+
+Write access is the most sensitive part in the program. This program is
+intended for <tt>editing filesystems</>. It is obvious that a small mistake
+in this regard can make the filesystem not usable anymore.
+
+The following safety measures are added, of-course, to the general Unix
+permission protection - The user can always disable write access on the
+device file itself.
+
+Considering the user, the following safety measures were taken:
+<enum>
+<item> The filesystem is <tt>never</> opened with write-access enables.
+ Rather, the user must explicitly request to enable write-access.
+<item> The user can <tt>disable</> write access entirely by using a
+ <tt>configuration file option</>.
+<item> Changes are never done automatically - Whenever the user makes
+ changes, they are done in memory. An explicit <tt>writedata</>
+ command should be issued to make the changes active in the disk.
+</enum>
+Considering myself, I tried to protect against my bugs by:
+<itemize>
+<item> Opening the device in read-only mode until a write request is
+ issued by the user.
+<item> Limiting <tt>actual</> filesystem access to two functions only -
+ <tt>low_read</> for reading, and <tt>low_write</> for writing. Those
+ functions were programmed carefully, and I added the self
+ sanity checks there. In addition, this is the only place in which I
+ need to check the user options described above - There can be no
+ place in which I can "forget" to check them.
+
+ Note that The disabling of write-access through the configuration file
+ is double checked here only as a <tt>self-sanity</> check - If
+ <tt>DEBUG</> is selected, since write enable should have been refused
+ and write-access is always disabled at startup, hence finding
+ <tt>here</> that the user has write access disabled through the
+ configuration file clearly indicates that I have a bug somewhere.
+</itemize>
+
+The following safety measure can provide protection against <tt>both</> user
+mistakes and my own bugs:
+<itemize>
+<item> I added a <tt>logging option</>, which logs every actual write
+ access to the disk in the lowest level - In <tt>low_write</> itself.
+
+ The logging has nothing to do with the current type and the various
+ other higher level operations of EXT2ED - It is simply a hex dump of
+ the contents which will be overwritten; Both the original contents
+ and the new written data.
+
+ In that case, even if the user makes a mistake, the original data
+ can be retrieved.
+
+ Even If I have a bug somewhere which causes incorrect data to be
+ written to the disk, the logging option will still log exactly the
+ original contents at the place were data was incorrectly overwritten.
+ (This assumes, of-course, that <tt>low-write</> and the <tt>logging
+ itself</> work correctly. I have done my best to verify that this is
+ indeed the case).
+
+ The <tt>logging</> option is implemented in the <tt>log_changes</>
+ function.
+</itemize>
+
+<sect1>Reading / Writing objects
+<p>
+
+Usually <tt>(not always)</>, the current object data is available in the
+global variable <tt>type_data</>, which is of the type:
+<tscreen><code>
+struct struct_type_data {
+ long offset_in_block;
+
+ union union_type_data {
+ char buffer [EXT2_MAX_BLOCK_SIZE];
+ struct ext2_acl_header t_ext2_acl_header;
+ struct ext2_acl_entry t_ext2_acl_entry;
+ struct ext2_old_group_desc t_ext2_old_group_desc;
+ struct ext2_group_desc t_ext2_group_desc;
+ struct ext2_inode t_ext2_inode;
+ struct ext2_super_block t_ext2_super_block;
+ struct ext2_dir_entry t_ext2_dir_entry;
+ } u;
+};
+</code></tscreen>
+The above union enables me, in the program, to treat the data as raw data or
+as a meaningful filesystem object.
+
+The reading and writing, if done to this global variable, are done through
+the functions <tt>load_type_data</> and <tt>write_type_data</>, available in
+<tt>disk.c</>.
+
+<sect>The general commands
+<p>
+
+The <tt>general commands</> are handled in the file <tt>general_com.c</>.
+
+<sect1>The help system
+<p>
+
+The help command is handled by the function <tt>help</>. The algorithm is as
+follows:
+
+<enum>
+<item> Check the command line arguments. If there is an argument, pass
+ control to the <tt>detailed_help</> function, in order to provide
+ help on the specific command.
+<item> If general help was requested, display a list of the available
+ commands at this point. The three levels are displayed in reverse
+ order - First the commands which are specific to the current type
+ (If a current type is defined), then the ext2 general commands (If
+ we decided that the filesystem should be treated like an ext2
+ filesystem), then the general commands.
+<item> Display information about EXT2ED - Current version, general
+ information about the project, etc.
+</enum>
+
+<sect1>The setdevice command
+<p>
+
+The <tt>setdevice</> commands result in calling the <tt>set_device</>
+function. The algorithm is:
+
+<enum>
+<item> Parse the command line argument. If it isn't available report the
+ error and return.
+<item> Close the current open device, if there is one.
+<item> Open the new device in read-only mode. Update the global variables
+ <tt>device_name</> and <tt>device_handle</>.
+<item> Disable write access.
+<item> Empty the object memory.
+<item> Unregister the ext2 general commands, using
+ <tt>free_user_commands</>.
+<item> Unregister the current objects, using <tt>free_struct_descriptors</>
+<item> Call <tt>set_file_system_info</> to auto-detect an ext2 filesystem
+ and set the basic filesystem values.
+<item> Add the <tt>alternate descriptors</>, supplied by the user.
+<item> Set the device offset to the filesystem start by dispatching
+ <tt>setoffset 0</>.
+<item> Show the new available commands by dispatching the <tt>help</>
+ command.
+</enum>
+
+<sect1>Basic maneuvering
+<p>
+
+Basic maneuvering is done using the <tt>setoffset</> and the <tt>settype</>
+user commands.
+
+<tt>set_offset</> accepts some alternative forms of specifying the new
+offset. They all ultimately lead to changing the <tt>device_offset</>
+global variable and seeking to the new position. <tt>set_offset</> also
+calls <tt>load_type_data</> to read a block ahead of the new position into
+the <tt>type_data</> global variable.
+
+<tt>set_type</> will point the global variable <tt>current_type</> to the
+correct entry in the double linked list of the known objects. If the
+requested type is <tt>hex</> or <tt>none</>, <tt>current_type</> will be
+initialized to <tt>NULL</>. <tt>set_type</> will also dispatch <tt>show</>,
+so that the object data will be re-formatted in the new format.
+
+When editing an ext2 filesystem, it is not intended that those commands will
+be used directly, and it is usually not required. My implementation of the
+ext2 layer, on the other hand, uses this lower level commands on countless
+occasions.
+
+<sect1>The display functions
+<p>
+
+The general command version of <tt>show</> is handled by the <tt>show</>
+function. This command is overridden by various objects to provide a display
+which is better suited to the object.
+
+The general show command will format the data in <tt>type_data</> according
+to the structure definition of the current type and show it on the <tt>show
+pad</>. If there is no current type, the data will be shown as a simple hex
+dump; Otherwise, the list of variables, along with their values will be shown.
+
+A call to <tt>show_info</> is also made - <tt>show_info</> will provide
+<tt>general statistics</> on the <tt>show_window</>, such as the current
+block, current type, current offset and current page.
+
+The <tt>pgup</> and <tt>pgdn</> general commands just update the
+<tt>show_pad_info</> global variable - We just increment
+<tt>show_pad_info.line</> with the number of lines in the screen -
+<tt>show_pad_info.display_lines</>, which was initialized in
+<tt>init_windows</>.
+
+<sect1>Changing data
+<p>
+
+Data change is done in memory only. An update to the disk if followed by an
+explicit <tt>writedata</> command to the disk. The <tt>write_data</>
+function simple calls the <tt>write_type_data</> function, outlined earlier.
+
+The <tt>set</> command is used for changing the data.
+
+If there is no current type, control is passed to the <tt>hex_set</> function,
+which treats the data as a block of bytes and uses the
+<tt>type_data.offset_in_block</> variable to write the new text or hex string
+to the correct place in the block.
+
+If a current type is defined, the requested variable is searched in the
+current object, and the desired new valued is entered.
+
+The <tt>enablewrite</> commands just sets the global variable
+<tt>write_access</> to <tt>1</> and re-opens the filesystem in read-write
+mode, if possible.
+
+If the current type is NULL, a hex-mode is assumed - The <tt>next</> and
+<tt>prev</> commands will just update <tt>type_data.offset_in_block</>.
+
+If the current type is not NULL, the The <tt>next</> and <tt>prev</> command
+are usually overridden anyway. If they are not overridden, it will be assumed
+that the user is editing an array of such objects, and they will just pass
+to the next / prev element by dispatching to <tt>setoffset</> using the
+<tt>setoffset type + / - X</> syntax.
+
+<sect>The ext2 general commands
+<p>
+
+The ext2 general commands are contained in the <tt>ext2_general_commands</>
+global variable (which is of type <tt>struct struct_commands</>).
+
+The handling functions are implemented in the source file <tt>ext2_com.c</>.
+I will include the entire source code since it is relatively short.
+
+<sect1>The super command
+<p>
+
+The super command just "brings the user" to the main superblock and set the
+type to ext2_super_block. The implementation is trivial:
+
+<tscreen><code>
+void type_ext2___super (char *command_line)
+
+{
+ char buffer [80];
+
+ super_info.copy_num=0;
+ sprintf (buffer,"setoffset %ld",file_system_info.super_block_offset);dispatch (buffer);
+ sprintf (buffer,"settype ext2_super_block");dispatch (buffer);
+}
+</code></tscreen>
+It involves only setting the <tt>copy_num</> variable to indicate the main
+copy, dispatching a <tt>setoffset</> command to reach the superblock, and
+dispatching a <tt>settype</> to enable the superblock specific commands.
+This last command will also call the <tt>show</> command of the
+<tt>ext2_super_block</> type, through dispatching at the general command
+<tt>settype</>.
+
+<sect1>The group command
+<p>
+
+The group command will bring the user to the specified group descriptor in
+the main copy of the group descriptors. The type will be set to
+<tt>ext2_group_desc</>:
+<tscreen><code>
+void type_ext2___group (char *command_line)
+
+{
+ long group_num=0;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ group_num=atol (buffer);
+ }
+
+ group_info.copy_num=0;group_info.group_num=0;
+ sprintf (buffer,"setoffset %ld",file_system_info.first_group_desc_offset);dispatch (buffer);
+ sprintf (buffer,"settype ext2_group_desc");dispatch (buffer);
+ sprintf (buffer,"entry %ld",group_num);dispatch (buffer);
+}
+</code></tscreen>
+The implementation is as trivial as the <tt>super</> implementation. Note
+the use of the <tt>entry</> command, which is a command of the
+<tt>ext2_group_desc</> object, to pass to the correct group descriptor.
+
+<sect1>The cd command
+<p>
+
+The <tt>cd</> command performs the usual cd function. The path to the global
+cd command is a path from <tt>/</>.
+
+<tt>This is one of the best examples of the power of the object oriented
+design and of the dispatching mechanism. The operation is complicated, yet the
+implementation is surprisingly short !</>
+
+<tscreen><code>
+void type_ext2___cd (char *command_line)
+
+{
+ char temp [80],buffer [80],*ptr;
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");
+ refresh_command_win ();return;
+ }
+ ptr=parse_word (ptr,buffer);
+
+ if (buffer [0] != '/') {
+ wprintw (command_win,"Error - Use a full pathname (begin with '/')\n");
+ refresh_command_win ();return;
+ }
+
+ dispatch ("super");dispatch ("group");dispatch ("inode");
+ dispatch ("next");dispatch ("dir");
+ if (buffer [1] != 0) {
+ sprintf (temp,"cd %s",buffer+1);dispatch (temp);
+ }
+}
+</code></tscreen>
+
+Note the number of the dispatch calls !
+
+<tt>super</> is used to get to the superblock. <tt>group</> to get to the
+first group descriptor. <tt>inode</> brings us to the first inode - The bad
+blocks inode. A <tt>next</> is command to pass to the root directory inode,
+a <tt>dir</> command "enters" the directory, and then we let the <tt>object
+specific cd command</> to take us from there (The object is <tt>dir</>, so
+that <tt>dispatch</> will call the <tt>cd</> command of the <tt>dir</> type).
+Note that a symbolic link following could bring us back to the root directory,
+thus the innocent calls above treats nicely such a recursive case !
+
+I feel that the above is <tt>intuitive</> - I was expressing myself "in the
+language" of the ext2 filesystem - (Go to the inode, etc), and the code was
+written exactly in this spirit !
+
+I can write more at this point, but I guess I am already a bit carried
+away with the self compliments :-)
+
+<sect>The superblock
+<p>
+
+This section details the handling of the superblock.
+
+<sect1>The superblock variables
+<p>
+
+The superblock object is <tt>ext2_super_block</>. The definition is just
+taken from the kernel ext2 main include file - /usr/include/linux/ext2_fs.h.
+<footnote>
+Those lines of source are copyrighted by <tt>Remy Card</> - The author of the
+ext2 filesystem, and by <tt>Linus Torvalds</> - The first author of the Linux
+operating system. Please cross reference the section Acknowledgments for the
+full copyright.
+</footnote>
+<tscreen><code>
+struct ext2_super_block {
+ __u32 s_inodes_count; /* Inodes count */
+ __u32 s_blocks_count; /* Blocks count */
+ __u32 s_r_blocks_count; /* Reserved blocks count */
+ __u32 s_free_blocks_count; /* Free blocks count */
+ __u32 s_free_inodes_count; /* Free inodes count */
+ __u32 s_first_data_block; /* First Data Block */
+ __u32 s_log_block_size; /* Block size */
+ __s32 s_log_frag_size; /* Fragment size */
+ __u32 s_blocks_per_group; /* # Blocks per group */
+ __u32 s_frags_per_group; /* # Fragments per group */
+ __u32 s_inodes_per_group; /* # Inodes per group */
+ __u32 s_mtime; /* Mount time */
+ __u32 s_wtime; /* Write time */
+ __u16 s_mnt_count; /* Mount count */
+ __s16 s_max_mnt_count; /* Maximal mount count */
+ __u16 s_magic; /* Magic signature */
+ __u16 s_state; /* File system state */
+ __u16 s_errors; /* Behavior when detecting errors */
+ __u16 s_pad;
+ __u32 s_lastcheck; /* time of last check */
+ __u32 s_checkinterval; /* max. time between checks */
+ __u32 s_creator_os; /* OS */
+ __u32 s_rev_level; /* Revision level */
+ __u16 s_def_resuid; /* Default uid for reserved blocks */
+ __u16 s_def_resgid; /* Default gid for reserved blocks */
+ __u32 s_reserved[0]; /* Padding to the end of the block */
+ __u32 s_reserved[1]; /* Padding to the end of the block */
+ .
+ .
+ .
+ __u32 s_reserved[234]; /* Padding to the end of the block */
+};
+</code></tscreen>
+
+Note that I <tt>expanded</> the array due to my primitive parser
+implementation. The various fields are described in the <tt>technical
+document</>.
+
+<sect1>The superblock commands
+<p>
+
+This section explains the commands available in the <tt>ext2_super_block</>
+type. They all appear in <tt>super_com.c</>
+
+<sect2>The show command
+<p>
+
+The <tt>show</> command is overridden here in order to provide more
+information than just the list of variables. A <tt>show</> command will end
+up in calling <tt>type_super_block___show</>.
+
+The first thing that we do is calling the <tt>general show command</> in
+order to display the list of variables.
+
+We then add some interpretation to the various lines to make the data
+somewhat more intuitive (Expansion of the time variables and the creator
+operating system code, for example).
+
+We also display the <tt>backup copy number</> of the superblock in the status
+window. This copy number is saved in the <tt>super_info</> global variable -
+<tt>super_info.copy_num</>. Currently, this is the only variable there ...
+but this type of internal variable saving is typical through my
+implementation.
+
+<sect2>The backup copies handling commands
+<p>
+
+The <tt>current copy number</> is available in <tt>super_info.copy_num</>. It
+was initialized in the ext2 command <tt>super</>, and is used by the various
+superblock routines.
+
+The <tt>gocopy</> routine will pass to another copy of the superblock. The
+new device offset will be computed with the aid of the variables in the
+<tt>file_system_info</> structure. Then the routine will <tt>dispatch</> to
+the <tt>setoffset</> and the <tt>show</> routines.
+
+The <tt>setactivecopy</> routine will just save the current superblock data
+in a temporary variable of type <tt>ext2_super_block</>, and will dispatch
+<tt>gocopy 0</> to pass to the main superblock. Then it will place the saved
+data in place of the actual data.
+
+The above two commands can be used if the main superblock is corrupted.
+
+<sect>The group descriptors
+<p>
+
+The group descriptors handling mechanism allows the user to take a tour in
+the group descriptors table, stopping at each point, and examining the
+relevant inode table, block allocation map or inode allocation map through
+dispatching to the relevant objects.
+
+Some information about the group descriptors is available in the global
+variable <tt>group_info</>, which is of type <tt>struct_group_info</>:
+
+<tscreen><code>
+struct struct_group_info {
+ unsigned long copy_num;
+ unsigned long group_num;
+};
+</code></tscreen>
+
+<tt>group_num</> is the index of the current descriptor in the table.
+
+<tt>copy_num</> is the number of the current backup copy.
+
+<sect1>The group descriptor's variables
+<p>
+
+<tscreen><code>
+struct ext2_group_desc
+{
+ __u32 bg_block_bitmap; /* Blocks bitmap block */
+ __u32 bg_inode_bitmap; /* Inodes bitmap block */
+ __u32 bg_inode_table; /* Inodes table block */
+ __u16 bg_free_blocks_count; /* Free blocks count */
+ __u16 bg_free_inodes_count; /* Free inodes count */
+ __u16 bg_used_dirs_count; /* Directories count */
+ __u16 bg_pad;
+ __u32 bg_reserved[3];
+};
+</code></tscreen>
+
+The first three variables are used to provide the links to the
+<tt>blockbitmap, inodebitmap and inode</> objects.
+
+<sect1>Movement in the table
+<p>
+
+Movement in the group descriptors table is done using the <tt>next, prev and
+entry</> commands. Note that the first two commands <tt>override</> the
+general commands of the same name. The <tt>next and prev</> command are just
+calling the <tt>entry</> function to do the job. I will show <tt>next</>,
+for example:
+
+<tscreen><code>
+void type_ext2_group_desc___next (char *command_line)
+
+{
+ long entry_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ entry_offset=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",group_info.group_num+entry_offset);
+ dispatch (buffer);
+}
+</code></tscreen>
+The <tt>entry</> function is also simple - It just calculates the offset
+using the information in <tt>group_info</> and in <tt>file_system_info</>,
+and uses the usual <tt>setoffset / show</> pair.
+
+<sect1>The show command
+<p>
+
+As usual, the <tt>show</> command is overridden. The implementation is
+similar to the superblock's show implementation - We just call the general
+show command, and add some information in the status window - The contents of
+the <tt>group_info</> structure.
+
+<sect1>Moving between backup copies
+<p>
+
+This is done exactly like the superblock case. Please refer to explanation
+there.
+
+<sect1>Links to the available friends
+<p>
+
+From a group descriptor, one typically wants to reach an <tt>inode</>, or
+one of the <tt>allocation bitmaps</>. This is done using the <tt>inode,
+blockbitmap or inodebitmap</> commands. The implementation is again trivial
+- Get the necessary information from the group descriptor, initialize the
+structures of the next type, and issue the <tt>setoffset / settype</> pair.
+
+For example, here is the implementation of the <tt>blockbitmap</> command:
+
+<tscreen><code>
+void type_ext2_group_desc___blockbitmap (char *command_line)
+
+{
+ long block_bitmap_offset;
+ char buffer [80];
+
+ block_bitmap_info.entry_num=0;
+ block_bitmap_info.group_num=group_info.group_num;
+
+ block_bitmap_offset=type_data.u.t_ext2_group_desc.bg_block_bitmap;
+ sprintf (buffer,"setoffset block %ld",block_bitmap_offset);dispatch (buffer);
+ sprintf (buffer,"settype block_bitmap");dispatch (buffer);
+}
+</code></tscreen>
+
+<sect>The inode table
+<p>
+
+The inode handling enables the user to move in the inode table, edit the
+various attributes of the inode, and follow to the next stage - A file or a
+directory.
+
+<sect1>The inode variables
+<p>
+
+<tscreen><code>
+struct ext2_inode {
+ __u16 i_mode; /* File mode */
+ __u16 i_uid; /* Owner Uid */
+ __u32 i_size; /* Size in bytes */
+ __u32 i_atime; /* Access time */
+ __u32 i_ctime; /* Creation time */
+ __u32 i_mtime; /* Modification time */
+ __u32 i_dtime; /* Deletion Time */
+ __u16 i_gid; /* Group Id */
+ __u16 i_links_count; /* Links count */
+ __u32 i_blocks; /* Blocks count */
+ __u32 i_flags; /* File flags */
+ union {
+ struct {
+ __u32 l_i_reserved1;
+ } linux1;
+ struct {
+ __u32 h_i_translator;
+ } hurd1;
+ struct {
+ __u32 m_i_reserved1;
+ } masix1;
+ } osd1; /* OS dependent 1 */
+ __u32 i_block[EXT2_N_BLOCKS]; /* Pointers to blocks */
+ __u32 i_version; /* File version (for NFS) */
+ __u32 i_file_acl; /* File ACL */
+ __u32 i_dir_acl; /* Directory ACL */
+ __u32 i_faddr; /* Fragment address */
+ union {
+ struct {
+ __u8 l_i_frag; /* Fragment number */
+ __u8 l_i_fsize; /* Fragment size */
+ __u16 i_pad1;
+ __u32 l_i_reserved2[2];
+ } linux2;
+ struct {
+ __u8 h_i_frag; /* Fragment number */
+ __u8 h_i_fsize; /* Fragment size */
+ __u16 h_i_mode_high;
+ __u16 h_i_uid_high;
+ __u16 h_i_gid_high;
+ __u32 h_i_author;
+ } hurd2;
+ struct {
+ __u8 m_i_frag; /* Fragment number */
+ __u8 m_i_fsize; /* Fragment size */
+ __u16 m_pad1;
+ __u32 m_i_reserved2[2];
+ } masix2;
+ } osd2; /* OS dependent 2 */
+};
+</code></tscreen>
+
+The above is the original source code definition. We can see that the inode
+supports <tt>Operating systems specific structures</>. In addition to the
+expansion of the arrays, I have <tt>"flattened</> the inode to support only
+the <tt>Linux</> declaration. It seemed that this one occasion of multiple
+variable aliases didn't justify the complication of generally supporting
+aliases. In any case, the above system specific variables are not used
+internally by EXT2ED, and the user is free to change the definition in
+<tt>ext2.descriptors</> to accommodate for his needs.
+
+<sect1>The handling functions
+<p>
+
+The user interface to <tt>movement</> is the usual <tt>next / prev /
+entry</> interface. There is really nothing special in those functions - The
+size of the inode is fixed, the total number of inodes is known from the
+superblock information, and the current entry can be figured up from the
+device offset and the inode table start offset, which is known from the
+corresponding group descriptor. Those functions are a bit older then some
+other implementations of <tt>next</> and <tt>prev</>, and they do not save
+information in a special structure. Rather, they recompute it when
+necessary.
+
+The <tt>show</> command is overridden here, and provides a lot of additional
+information about the inode - Its type, interpretation of the permissions,
+special ext2 attributes (Immutable file, for example), and a lot more.
+Again, the <tt>general show</> is called first, and then the additional
+information is written.
+
+<sect1>Accessing files and directories
+<p>
+
+From the inode, a <tt>file</> or a <tt>directory</> can typically be reached.
+In order to treat a file, for example, its inode needs to be constantly
+accessed. To satisfy that need, when editing a file or a directory, the
+inode is still saved in memory - <tt>type_data</> is not overwritten.
+Rather, the following takes place:
+<itemize>
+<item> An internal global structure which is used by the types <tt>file</>
+ and <tt>dir</> handling functions is initialized by calling the
+ appropriate function.
+<item> The type is changed accordingly.
+</itemize>
+The result is that a <tt>settype ext2_inode</> is the only action necessary
+to return to the inode - We actually never left it.
+
+Follows the implementation of the inode's <tt>file</> command:
+
+<tscreen><code>
+void type_ext2_inode___file (char *command_line)
+
+{
+ char buffer [80];
+
+ if (!S_ISREG (type_data.u.t_ext2_inode.i_mode)) {
+ wprintw (command_win,"Error - Inode type is not file\n");
+ refresh_command_win (); return;
+ }
+
+ if (!init_file_info ()) {
+ wprintw (command_win,"Error - Unable to show file\n");
+ refresh_command_win ();return;
+ }
+
+ sprintf (buffer,"settype file");dispatch (buffer);
+}
+</code></tscreen>
+
+As we can see - We just call <tt>init_file_info</> to get the necessary
+information from the inode, and set the type to <tt>file</>. The next call
+to <tt>show</>, will dispatch to the <tt>file's show</> implementation.
+
+<sect>Viewing a file
+<p>
+
+There isn't an ext2 kernel structure which corresponds to a file - A file is
+just a series of blocks which are determined by its inode. As explained in
+the last section, the inode is never actually left - The type is changed to
+<tt>file</> - A type which contains no variables, and a special structure is
+initialized:
+
+<tscreen><code>
+struct struct_file_info {
+
+ struct ext2_inodes *inode_ptr;
+
+ long inode_offset;
+ long global_block_num,global_block_offset;
+ long block_num,blocks_count;
+ long file_offset,file_length;
+ long level;
+ unsigned char buffer [EXT2_MAX_BLOCK_SIZE];
+ long offset_in_block;
+
+ int display;
+ /* The following is used if the file is a directory */
+
+ long dir_entry_num,dir_entries_count;
+ long dir_entry_offset;
+};
+</code></tscreen>
+
+The <tt>inode_ptr</> will just point to the inode in <tt>type_data</>, which
+is not overwritten while the user is editing the file, as the
+<tt>setoffset</> command is not internally used. The <tt>buffer</>
+will contain the current viewed block of the file. The other variables
+contain information about the current place in the file. For example,
+<tt>global_block_num</> just contains the current block number.
+
+The general idea is that the above data structure will provide the file
+handling functions all the accurate information which is needed to accomplish
+their task.
+
+The global structure of the above type, <tt>file_info</>, is initialized by
+<tt>init_file_info</> in <tt>file_com.c</>, which is called by the
+<tt>type_ext2_inode___file</> function when the user requests to watch the
+file. <tt>It is updated as necessary to provide accurate information as long as
+the file is edited.</>
+
+<sect1>Returning to the file's inode
+<p>
+
+Concerning the method I used to handle files, the above task is trivial:
+<tscreen><code>
+void type_file___inode (char *command_line)
+
+{
+ dispatch ("settype ext2_inode");
+}
+</code></tscreen>
+
+<sect1>File movement
+<p>
+
+EXT2ED keeps track of the current position in the file. Movement inside the
+current block is done using <tt>next, prev and offset</> - They just change
+<tt>file_info.offset_in_block</>.
+
+Movement between blocks is done using <tt>nextblock, prevblock and block</>.
+To accomplish this, the direct blocks, indirect blocks, etc, need to be
+traced. This is done by <tt>file_block_to_global_block</>, which accepts a
+file's internal block number, and converts it to the actual filesystem block
+number.
+
+<tscreen><code>
+long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr)
+
+{
+ long last_direct,last_indirect,last_dindirect;
+ long f_indirect,s_indirect;
+
+ last_direct=EXT2_NDIR_BLOCKS-1;
+ last_indirect=last_direct+file_system_info.block_size/4;
+ last_dindirect=last_indirect+(file_system_info.block_size/4) \
+ *(file_system_info.block_size/4);
+
+ if (file_block <= last_direct) {
+ file_info_ptr->level=0;
+ return (file_info_ptr->inode_ptr->i_block [file_block]);
+ }
+
+ if (file_block <= last_indirect) {
+ file_info_ptr->level=1;
+ file_block=file_block-last_direct-1;
+ return (return_indirect (file_info_ptr->inode_ptr-> \
+ i_block [EXT2_IND_BLOCK],file_block));
+ }
+
+ if (file_block <= last_dindirect) {
+ file_info_ptr->level=2;
+ file_block=file_block-last_indirect-1;
+ return (return_dindirect (file_info_ptr->inode_ptr-> \
+ i_block [EXT2_DIND_BLOCK],file_block));
+ }
+
+ file_info_ptr->level=3;
+ file_block=file_block-last_dindirect-1;
+ return (return_tindirect (file_info_ptr->inode_ptr-> \
+ i_block [EXT2_TIND_BLOCK],file_block));
+}
+</code></tscreen>
+<tt>last_direct, last_indirect, etc</>, contain the last internal block number
+which is accessed by this method - If the requested block is smaller then
+<tt>last_direct</>, for example, it is a direct block.
+
+If the block is a direct block, its number is just taken from the inode.
+A non-direct block is handled by <tt>return_indirect, return_dindirect and
+return_tindirect</>, which correspond to indirect, double-indirect and
+triple-indirect. Each of the above functions is constructed using the lower
+level functions. For example, <tt>return_dindirect</> is constructed as
+follows:
+
+<tscreen><code>
+long return_dindirect (long table_block,long block_num)
+
+{
+ long f_indirect;
+
+ f_indirect=block_num/(file_system_info.block_size/4);
+ f_indirect=return_indirect (table_block,f_indirect);
+ return (return_indirect (f_indirect,block_num%(file_system_info.block_size/4)));
+}
+</code></tscreen>
+
+<sect1>Object memory
+<p>
+
+The <tt>remember</> command is overridden here and in the <tt>dir</> type -
+We just remember the inode of the file. It is just simpler to implement, and
+doesn't seem like a big limitation.
+
+<sect1>Changing data
+<p>
+
+The <tt>set</> command is overridden, and provides the same functionality
+like the usage of the <tt>general set</> command with no type declared. The
+<tt>writedata</> is overridden so that we'll write the edited block
+(file_info.buffer) and not <tt>type_data</> (Which contains the inode).
+
+<sect>Directories
+<p>
+
+A directory is just a file which is formatted according to a special format.
+As such, EXT2ED handles directories and files quite alike. Specifically, the
+same variable of type <tt>struct_file_info</> which is used in the
+<tt>file</>, is used here.
+
+The <tt>dir</> type uses all the variables in the above structure, as
+opposed to the <tt>file</> type, which didn't use the last ones.
+
+<sect1>The search_dir_entries function
+<p>
+
+The entire situation is similar to that which was described in the
+<tt>file</> type, with one main change:
+
+The main function in <tt>dir_com.c</> is <tt>search_dir_entries</>. This
+function will <tt>"run"</> on the entire entries in the directory, and will
+call a client's function each time. The client's function is supplied as an
+argument, and will check the current entry for a match, based on its own
+criterion. It will then signal <tt>search_dir_entries</> whether to
+<tt>ABORT</> the search, whether it <tt>FOUND</> the entry it was looking
+for, or that the entry is still not found, and we should <tt>CONTINUE</>
+searching. Follows the declaration:
+<tscreen><code>
+struct struct_file_info search_dir_entries \
+ (int (*action) (struct struct_file_info *info),int *status)
+
+/*
+ This routine runs on all directory entries in the current directory.
+ For each entry, action is called. The return code of action is one of
+ the following:
+
+ ABORT - Current dir entry is returned.
+ CONTINUE - Continue searching.
+ FOUND - Current dir entry is returned.
+
+ If the last entry is reached, it is returned, along with an ABORT status.
+
+ status is updated to the returned code of action.
+*/
+</code></tscreen>
+
+With the above tool in hand, many operations are simple to perform - Here is
+the way I counted the entries in the current directory:
+
+<tscreen><code>
+long count_dir_entries (void)
+
+{
+ int status;
+
+ return (search_dir_entries (&ero;action_count,&ero;status).dir_entry_num);
+}
+
+int action_count (struct struct_file_info *info)
+
+{
+ return (CONTINUE);
+}
+</code></tscreen>
+It will just <tt>CONTINUE</> until the last entry. The returned structure
+(of type <tt>struct_file_info</>) will have its number in the
+<tt>dir_entry_num</> field, and this is exactly the required number !
+
+<sect1>The cd command
+<p>
+
+The <tt>cd</> command accepts a relative path, and moves there ...
+The implementation is of-course a bit more complicated:
+<enum>
+<item> The path is checked that it is not an absolute path (from <tt>/</>).
+ If it is, we let the <tt>general cd</> to do the job by calling
+ directly <tt>type_ext2___cd</>.
+<item> The path is divided into the nearest path and the rest of the path.
+ For example, cd 1/2/3/4 is divided into <tt>1</> and into
+ <tt>2/3/4</>.
+<item> It is the first part of the path that we need to search for in the
+ current directory. We search for it using <tt>search_dir_entries</>,
+ which accepts the <tt>action_name</> function as the user defined
+ function.
+<item> <tt>search_dir_entries</> will scan the entire entries and will call
+ our <tt>action_name</> function for each entry. In
+ <tt>action_name</>, the required name will be checked against the
+ name of the current entry, and <tt>FOUND</> will be returned when a
+ match occurs.
+<item> If the required entry is found, we dispatch a <tt>remember</>
+ command to insert the current <tt>inode</> into the object memory.
+ This is required to easily support <tt>symbolic links</> - If we
+ find later that the inode pointed by the entry is actually a
+ symbolic link, we'll need to return to this point, and the above
+ inode doesn't have (and can't have, because of <tt>hard links</>) the
+ information necessary to "move back".
+<item> We then dispatch a <tt>followinode</> command to reach the inode
+ pointed by the required entry. This command will automatically
+ change the type to <tt>ext2_inode</> - We are now at an inode, and
+ all the inode commands are available.
+<item> We check the inode's type to see if it is a directory. If it is, we
+ dispatch a <tt>dir</> command to "enter the directory", and
+ recursively call ourself (The type is <tt>dir</> again) by
+ dispatching a <tt>cd</> command, with the rest of the path as an
+ argument.
+<item> If the inode's type is a symbolic link (only fast symbolic link were
+ meanwhile implemented. I guess this is typically the case.), we note
+ the path it is pointing at, the saved inode is recalled, we dispatch
+ <tt>dir</> to get back to the original directory, and we call
+ ourself again with the <tt>link path/rest of the path</> argument.
+<item> In any other case, we just stop at the resulting inode.
+</enum>
+
+<sect>The block and inode allocation bitmaps
+<p>
+
+The block allocation bitmap is reached by the corresponding group descriptor.
+The group descriptor handling functions will save the necessary information
+into a structure of the <tt>struct_block_bitmap_info</> type:
+
+<tscreen><code>
+struct struct_block_bitmap_info {
+ unsigned long entry_num;
+ unsigned long group_num;
+};
+</code></tscreen>
+
+The <tt>show</> command is overridden, and will show the block as a series of
+bits, each bit corresponding to a block. The main variable is the
+<tt>entry_num</> variable, declared above, which is just the current block
+number in this block group. The current entry is highlighted, and the
+<tt>next, prev and entry</> commands just change the above variable.
+
+The <tt>allocate and deallocate</> change the specified bits. Nothing
+special about them - They just contain code which converts between bit and
+byte locations.
+
+The <tt>inode allocation bitmap</> is treated in much the same fashion, with
+the same commands available.
+
+<sect>Filesystem size limitation
+<p>
+
+While an ext2 filesystem has a size limit of <tt>4 TB</>, EXT2ED currently
+<tt>can't</> handle filesystems which are <tt>bigger than 2 GB</>.
+
+This limitation results from my usage of <tt>32 bit long variables</> and
+of the <tt>fseek</> filesystem call, which can't seek up to 4 TB.
+
+By looking in the <tt>ext2 library</> source code by <tt>Theodore Ts'o</>,
+I discovered the <tt>llseek</> system call which can seek to a
+<tt>64 bit unsigned long long</> offset. Correcting the situation is not
+difficult in concept - I need to change long into unsigned long long where
+appropriate and modify <tt>disk.c</> to use the llseek system call.
+
+However, fixing the above limitation involves making changes in many places
+in the code and will obviously make the entire code less stable. For that
+reason, I chose to release EXT2ED as it is now and to postpone the above fix
+to the next release.
+
+<sect>Conclusion
+<p>
+
+Had I known in advance the structure of the ext2 filesystem, I feel that
+the resulting design would have been quite different from the presented
+design above.
+
+EXT2ED has now two levels of abstraction - A <tt>general</> filesystem, and an
+<tt>ext2</> filesystem, and the surface is more or less prepared for additions
+of other filesystems. Had I approached the design in the "engineering" way,
+I guess that the first level above would not have existed.
+
+<sect>Copyright
+<p>
+
+EXT2ED is Copyright (C) 1995 Gadi Oxman.
+
+EXT2ED is hereby placed under the GPL - Gnu Public License. You are free and
+welcome to copy, view and modify the sources. My only wish is that my
+copyright presented above will be left and that a list of the bug fixes,
+added features, etc, will be provided.
+
+The entire EXT2ED project is based, of-course, on the kernel sources. The
+<tt>ext2.descriptors</> distributed with EXT2ED is a slightly modified
+version of the main ext2 include file, /usr/include/linux/ext2_fs.h. Follows
+the original copyright:
+
+<tscreen><verb>
+/*
+ * linux/include/linux/ext2_fs.h
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/include/linux/minix_fs.h
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+</verb></tscreen>
+
+<sect>Acknowledgments
+<p>
+
+EXT2ED was constructed as a student project in the software
+laboratory of the faculty of electrical-engineering in the
+<tt>Technion - Israel's institute of technology</>.
+
+At first, I would like to thank <tt>Avner Lottem</> and <tt>Doctor Ilana
+David</> for their interest and assistance in this project.
+
+I would also like to thank the following people, who were involved in the
+design and implementation of the ext2 filesystem kernel code and support
+utilities:
+<itemize>
+<item> <tt>Remy Card</>
+
+ Who designed, implemented and maintains the ext2 filesystem kernel
+ code, and some of the ext2 utilities. <tt>Remy Card</> is also the
+ author of several helpful slides concerning the ext2 filesystem.
+ Specifically, he is the author of <tt>File Management in the Linux
+ Kernel</> and of <tt>The Second Extended File System - Current
+ State, Future Development</>.
+
+<item> <tt>Wayne Davison</>
+
+ Who designed the ext2 filesystem.
+<item> <tt>Stephen Tweedie</>
+
+ Who helped designing the ext2 filesystem kernel code and wrote the
+ slides <tt>Optimizations in File Systems</>.
+<item> <tt>Theodore Ts'o</>
+
+ Who is the author of several ext2 utilities and of the ext2 library
+ <tt>libext2fs</> (which I didn't use, simply because I didn't know
+ it exists when I started to work on my project).
+</itemize>
+
+Lastly, I would like to thank, of-course, <tt>Linus Torvalds</> and the
+<tt>Linux community</> for providing all of us with such a great operating
+system.
+
+Please contact me in a case of bug report, suggestions, or just about
+anything concerning EXT2ED.
+
+Enjoy,
+
+Gadi Oxman &lt;tgud@tochnapc2.technion.ac.il&gt;
+
+Haifa, August 95
+</article> \ No newline at end of file
diff --git a/ext2ed/doc/ext2ed.8 b/ext2ed/doc/ext2ed.8
new file mode 100644
index 00000000..e153ff8b
--- /dev/null
+++ b/ext2ed/doc/ext2ed.8
@@ -0,0 +1,72 @@
+.\" -*- nroff -*-
+.TH EXT2ED 8 "August 1995" "Version 0.1"
+.SH NAME
+ext2ed \- ext2 file system editor
+.SH SYNOPSIS
+.B ext2ed
+.SH DESCRIPTION
+.B ext2ed
+in an
+.B editor
+for the
+.B second extended filesystem.
+Its aim is to show you the various internal filesystem structures in an
+intuitive form so that you would be able to easily understand and modify
+them.
+.SH DOCUMENTATION
+The documentation is not available in man page format. Instead, I have
+written three articles which are related to ext2ed:
+
+The first article is
+.B The user's guide.
+This article explains how to use ext2ed.
+
+The second article is
+.B The Ext2fs overview.
+This article gives an overview of internal structure of the ext2 filesystem.
+You need to understand the internal layout in order to effectively edit
+your filesystem.
+
+The third article is
+.B EXT2ED - Design and implementation.
+This article explains how I constructed ext2ed. You may want to have a look
+in it if you plan to view or modify the source code.
+
+.SH WARNING
+
+.B
+Do not use ext2ed on a mounted filesystem.
+
+.SH FILES
+.TP
+.I /usr/bin/ext2ed
+The program itself.
+.TP
+.I /var/lib/ext2ed/ext2ed.conf
+ext2ed's configuration file.
+.TP
+.I /var/lib/ext2ed/ext2.descriptors
+Definition of the various objects for the ext2 filesystem.
+.TP
+.I /var/lib/ext2ed/ext2ed.log
+Log file of actual changes made to the filesystem.
+.TP
+.I /usr/man/man8/ext2ed.8
+The manual page.
+.TP
+.I /usr/doc/ext2ed/user-guide-0.1.ps
+The user's guide.
+.TP
+.I /usr/doc/ext2ed/Ext2fs-overview-0.1.ps
+Technical overview of the ext2 filesystem.
+.TP
+.I /usr/doc/ext2ed/ext2ed-design-0.1.ps
+EXT2ED design notes.
+
+.SH BUGS
+Filesystems bigger than 2 GB aren't yet supported.
+.SH AUTHOR
+Gadi Oxman <tgud@tochnapc2.technion.ac.il>
+.SH SEE ALSO
+.BR e2fsck (8),
+.BR debugfs (8)
diff --git a/ext2ed/doc/user-guide-0.1.sgml b/ext2ed/doc/user-guide-0.1.sgml
new file mode 100644
index 00000000..c494a7e7
--- /dev/null
+++ b/ext2ed/doc/user-guide-0.1.sgml
@@ -0,0 +1,1189 @@
+<!doctype linuxdoc system>
+
+<!-- EXT2ED user's guide -->
+<!-- First written: July 22 1995 -->
+<!-- Last updated: August 3 1995 -->
+<!-- This document is written Using the Linux documentation project Linuxdoc-SGML DTD -->
+
+<article>
+
+<title>EXT2ED - The Extended-2 filesystem editor - User's guide
+<author>Gadi Oxman, tgud@tochnapc2.technion.ac.il
+<date>v0.1, August 3 1995
+<abstract>
+This is only the initial version of this document. It may be unclear at
+some places. Please send me feedback with anything regarding to it.
+</abstract>
+<toc>
+
+<!-- Begin of document -->
+
+<sect>About EXT2ED documentation
+<p>
+
+The EXT2ED documentation consists of three parts:
+<itemize>
+<item> The ext2 filesystem overview.
+<item> The EXT2ED user's guide.
+<item> The EXT2ED design and implementation.
+</itemize>
+
+If you intend to used EXT2ED, I strongly suggest that you would be familiar
+with the material presented in the <tt>ext2 filesystem overview</> as well.
+
+If you also intend to browse and modify the source code, I suggest that you
+will also read the article <tt>The EXT2ED design and implementation</>, as it
+provides a general overview of the structure of my source code.
+
+<sect>Introduction
+
+<p>
+EXT2ED is a "disk editor" for the ext2 filesystem. Its purpose is to show
+you the internal structures of the ext2 filesystem in an rather intuitive
+and logical way, so that it will be easier to "travel" between the various
+internal filesystem structures.
+
+<sect>Basic concepts in EXT2ED
+
+<p>
+Two basic concepts in EXT2ED are <tt>commands</> and <tt>types</>.
+
+EXT2ED is object-oriented in the sense that it defines objects in the
+filesystem, like a <tt>super-block</> or a <tt>directory</>. An object is
+something which "knows" how to handle some aspect of the filesystem.
+
+Your interaction with EXT2ED is done through <tt>commands</> which EXT2ED
+accepts. There are three levels of commands:
+<itemize>
+<item> General Commands
+<item> Extended-2 Filesystem general commands
+<item> Type specific commands
+</itemize>
+The General commands are always available.
+
+The ext2 general commands are available only when editing an ext2 filesystem.
+
+The Type specific commands are available when editing a specific object in the
+filesystem. Each object typically comes with its own set of internal
+variables, and its own set of commands, which are fine tuned handle the
+corresponding structure in the filesystem.
+<sect>Running EXT2ED
+<p>
+Running EXT2ED is as simple as typing <tt>ext2ed</> from the shell prompt.
+There are no command line switches.
+
+When first run, EXT2ED parses its configuration file, <tt>ext2ed.conf</>.
+This file must exist.
+
+When the configuration file processing is done, EXT2ED screen should appear
+on the screen, with the command prompt <tt>ext2ed></> displayed.
+
+<sect>EXT2ED user interface
+
+<p>
+EXT2ED uses the <em>ncurses</> library for screen management. Your screen
+will be divided into four parts, from top to bottom:
+<itemize>
+<item> Title window
+<item> Status window
+<item> Main editing window
+<item> Command window
+</itemize>
+The title window just displays the current version of EXT2ED.
+
+The status window will display various information regarding the state of
+the editing at this point.
+
+The main editing window is the place at which the actual data will be shown.
+Almost every command will cause some display at this window. This window, as
+opposed to the three others, is of variable length - You always look at one
+page of it. The current page and the total numbers of pages at this moment
+is displayed at the status window. Moving between pages is done by the use
+of the <tt>pgdn</> and <tt>pgup</> commands.
+
+The command window is at the bottom of the screen. It always displays a
+command prompt <tt>ext2ed></> and allows you to type a command. Feedback
+about the commands entered is displayed to this window also.
+
+EXT2ED uses the <em>readline</> library while processing a command line. All
+the usual editing keys are available. Each entered command is placed into a
+history of commands, and can be recalled later. Command Completion is also
+supported - Just start to type a command, and press the completion key.
+
+Pressing <tt>enter</> at the command window, without entering a command,
+recalls the last command. This is useful when moving between close entries,
+in the <tt>next</> command, for example.
+
+<sect>Getting started
+
+<p>
+
+<sect1>A few precautions
+
+<p>
+
+EXT2ED is a tool for filesystem <tt>editing</>. As such, it can be
+<tt>dangerous</>. The summary to the subsections below is that
+<tt>You must know what you are doing</>.
+
+<sect2><label id="mounted_ref">A mounted filesystem
+
+<p>
+
+EXT2ED is not designed to work on a mounted filesystem - It is complicated
+enough as it is; I didn't even try to think of handling the various race
+conditions. As such, please respect the following advice:
+
+<tt>Do not use EXT2ED on a mounted filesystem !</>
+
+EXT2ED will not allow write access to a mounted filesystem. Although it is
+fairly easy to change EXT2ED so that it will be allowed, I hereby request
+again- EXT2ED is not designed for that action, and will most likely corrupt
+data if used that way. Please don't do that.
+
+Concerning read access, I chose to leave the decision for the user through
+the configuration file option <tt>AllowMountedRead</>. Although read access
+on a mounted partition will not do any damage to the filesystem, the data
+displayed to you will not be reliable, and showing you incorrect information
+may be as bad as corrupting the filesystem. However, you may still wish to
+do that.
+
+<sect2>Write access
+
+<p>
+
+Considering the obvious sensitivity of the subject, I took the following
+actions:
+
+<enum>
+<item> EXT2ED will always start with a read-only access. Write access mode
+ needs to be specifically entered by the <tt>enablewrite</> command.
+ Until this is done, no write will be allowed. Write access can be
+ disabled at any time with <tt>disablewrite</>. When
+ <tt>enablewrite</> is issued, the device is reopened in read-write
+ mode. Needless to say, the device permissions should allow that.
+<item> As a second level of protection, you can disallow write access in
+ the configuration file by using the <tt>AllowChanges off</>
+ configuration option. In this case, the <tt>enablewrite</> command
+ will be refused.
+<item> When write access is enabled, the data will never change
+ immediately. Rather, a specific <tt>writedata</> command is needed
+ to update the object in the disk with the changed object in memory.
+<item> In addition, A logging option is provided through the configuration
+ file options <tt>LogChanges</> and <tt>LogFile</>. With logging
+ enabled, each change to the disk will be logged at a very primitive
+ level - A hex dump of the original data and of the new written data.
+ The log file will be a text file which is easily readable, and you
+ can make use of it to undo any changes which you made (EXT2ED doesn't
+ make use of the log file for that purpose, it just logs the changes).
+</enum>
+Please remember that this is only the initial release of EXT2ED, and it is
+not very much tested - It is reasonable to assume that <tt>there are
+bugs</>.
+However, the logging option above can offer protection even from this
+unfortunate case. Therefor, I highly recommend that at least when first
+working with EXT2ED, the logging option will be enabled, despite the disk
+space which it consumes.
+
+<sect1><label id="help_ref">The help command
+
+<p>
+
+When loaded, EXT2ED will show a short help screen. This help screen can
+always be retrieved by the command <tt>help</>. The help screen displays a
+list of all the commands which are available at this point. At startup, only
+the <tt>General commands</> are available.
+This will change with time, since each object has its own commands. Thus,
+commands which are available now may not be available later.
+Using <tt>help</> <em>command</> will display additional information about
+the specific command <em>command</>.
+
+<sect1><label id="setdevice_ref">The setdevice command
+
+<p>
+
+The first command that is usually entered to EXT2ED is the <tt>setdevice</>
+command. This command simply tells EXT2ED on which device the filesystem is
+present. For example, suppose my ext2 filesystem is on the first partition
+of my ide disk. The command will be:
+<tscreen><verb>
+setdevice /dev/hda1
+</verb></tscreen>
+The following actions will take place in the following order:
+<enum>
+<item> EXT2ED will check if the partition is mounted.
+ If the partition is mounted (<tt>highly not recommended</>),
+ the accept/reject behavior will be decided by the configuration
+ file. Cross reference section <ref id="mounted_ref">.
+<item> The specified device will be opened in read-only mode. The
+ permissions of the device should be set in a way that allows
+ you to open the device for read access.
+<item> Autodetection of an ext2 filesystem will be made by searching for
+ the ext2 magic number in the main superblock.
+<item> In the case of a successful recognition of an ext2 filesystem, the
+ ext2 filesystem specific commands and the ext2 specific object
+ definitions will be registered. The object definitions will be read
+ at run time from a file specified by the configuration file.
+
+ In case of a corrupted ext2 filesystem, it is quite possible that
+ the main superblock is damaged and autodetection will fail. In that
+ case, use the configuration option <tt>ForceExt2 on</>. This is not
+ the default case since EXT2ED can be used at a lower level to edit a
+ non-ext2 filesystem.
+<item> In a case of a successful autodetection, essential information about
+ the filesystem such as the block size will be read from the
+ superblock, unless the used overrides this behavior with an
+ configuration option (not recommended). In that case, the parameters
+ will be read from the configuration file.
+
+ In a case of an autodetection failure, the essential parameters
+ will be read from the configuration file.
+</enum>
+Assuming that you are editing an ext2 filesystem and that everything goes
+well, you will notice that additional commands are now available in the help
+screen, under the section <tt>ext2 filesystem general commands</>. In
+addition, EXT2ED now recognizes a few objects which are essential to the
+editing of an ext2 filesystem.
+
+<sect>Two levels of usage
+
+<p>
+
+<sect1>Low level usage
+
+<p>
+This section explains what EXT2ED provides even when not editing an ext2
+filesystem.
+
+Even at this level, EXT2ED is more than just a hex editor. It still allows
+definition of objects and variables in run time through a user file,
+although of-course the objects will not have special fine tuned functions
+connected to them. EXT2ED will allow you to move in the filesystem using
+<tt>setoffset</>, and to apply an object definition on a specific place
+using <tt>settype</> <em>type</>. From this point and on, the object will
+be shown <tt>in its native form</> - You will see a list of the
+variables rather than just a hex dump, and you will be able to change each
+variable in the intuitive form <tt>set variable=value</>.
+
+To define objects, use the configuration option <tt>AlternateDescriptors</>.
+
+There are now two forms of editing:
+<itemize>
+<item> Editing without a type. In this case, the disk block will be shown
+as a text+hex dump, and you will be able to move along and change it.
+<item> Editing with a type. In this case, the object's variables will be
+shown, and you will be able to change each variable in its native form.
+</itemize>
+
+<sect1>High level usage
+
+<p>
+EXT2ED was designed for the editing of the ext2 filesystem. As such, it
+"understands" the filesystem structure to some extent. Each object now has
+special fine tuned 'C' functions connected to it, which knows how to display
+it in an intuitive form, and how the object fits in the general design of
+the ext2 filesystem. It is of-course much easier to use this type of
+editing. For example:
+<tscreen>
+Issue <em>group 2</> to look at the main copy of the third group block
+descriptor. With <em>gocopy 1</> you can move to its first backup copy,
+and with <em>inode</> you can start editing the inode table of the above
+group block. From here, if the inode corresponds to a file, you can
+use <em>file</> to edit the file in a "continuous" way, using
+<em>nextblock</> to pass to its next block, letting EXT2ED following by
+itself the direct blocks, indirect blocks, ..., while still preserving the
+actual view of the exact block usage of the file.
+</tscreen>
+The point is that the "tour" of the filesystem will now be synchronic rather
+than asynchronic - Each object has the "links" to pass between connected
+logical structures, and special fine-tuned functions to deal with it.
+
+<sect>General commands
+
+<p>
+I will now start with a systematic explanation of the general commands.
+Please feel free to experiment, but take care when using the
+<tt>enablewrite</> command.
+
+Whenever a command syntax is specified, arguments which are optional are
+enclosed with square brackets.
+
+Please note that in EXT2ED, each command can be overridden by a specific
+object to provide special fine-tuned functionality. In general, I was
+attempting to preserve the similarity between those functions, which are
+accessible by the same name.
+
+<sect1><label id="disablewrite_ref">disablewrite
+<p>
+<tscreen><verb>
+Syntax: disablewrite
+</verb></tscreen>
+<tt>disablewrite</> is used to reopen the device with read-only access. When
+first running EXT2ED, the device is opened in read-only mode, and an
+explicit <tt>enablewrite</> is required for write access. When finishing
+with changing, a <tt>disablewrite</> is recommended for safety. Cross
+reference section <ref id="disablewrite_ref">.
+
+<sect1><label id="enablewrite_ref">enablewrite
+<p>
+<tscreen><verb>
+Syntax: enablewrite
+</verb></tscreen>
+<tt>enablewrite</> is used to reopen the device with read-write access.
+When first running EXT2ED, the device is opened in read-only mode, and an
+explicit <tt>enablewrite</> is required for write access.
+<tt>enablewrite</> will fail if write access is disabled from the
+configuration file by the <tt>AllowChanges off</> configuration option.
+Even after <tt>enablewrite</>, an explicit <tt>writedata</>
+is required to actually write the new data to the disk.
+When finishing with changing, a <tt>disablewrite</> is recommended for safety.
+Cross reference section <ref id="enablewrite_ref">.
+
+<sect1>help
+<p>
+<tscreen><verb>
+Syntax: help [command]
+</verb></tscreen>
+The <tt>help</> command is described at section <ref id="help_ref">.
+
+<sect1><label id="next_ref">next
+<p>
+<tscreen><verb>
+Syntax: next [number]
+</verb></tscreen>
+This section describes the <em>general command</> <tt>next</>. <tt>next</>
+is overridden by several types in EXT2ED, to provide fine-tuned
+functionality.
+
+The <tt>next general command</> behavior is depended on whether you are editing a
+specific object, or none.
+
+<itemize>
+<item> In the case where Type is <tt>none</> (The current type is showed
+ on the status window by the <tt>show</> command), <tt>next</>
+ passes to the next <em>number</> bytes in the current edited block.
+ If <em>number</> is not specified, <em>number=1</> is assumed.
+<item> In the case where Type is defined, the <tt>next</> commands assumes
+ that you are editing an array of objects of that type, and the
+ <tt>next</> command will just pass to the next entry in the array.
+ If <em>number</> is defined, it will pass <em>number</> entries
+ ahead.
+</itemize>
+
+<sect1><label id="pgdn_ref">pgdn
+<p>
+<tscreen><verb>
+Syntax: pgdn
+</verb></tscreen>
+Usually the edited data doesn't fit into the visible main window. In this
+case, the status window will indicate that there is more to see "below" by
+the message <tt>Page x of y</>. This means that there are <em>y</> pages
+total, and you are currently viewing the <em>x</> page. With the <tt>pgdn</>
+command, you can pass to the next available page.
+
+<sect1>pgup
+<p>
+<tscreen><verb>
+Syntax: pgup
+</verb></tscreen>
+
+<tt>pgup</> is the opposite of <tt>pgdn</> - It will pass to the previous
+page. Cross reference section <ref id="pgdn_ref">.
+
+<sect1>prev
+<p>
+<tscreen><verb>
+Syntax: prev [number]
+</verb></tscreen>
+
+<tt>prev</> is the opposite of <tt>next</>. Cross reference section
+<ref id="next_ref">.
+
+<sect1><label id="recall_ref">recall
+<p>
+<tscreen><verb>
+Syntax: recall object
+</verb></tscreen>
+<tt>recall</> is the opposite of <tt>remember</>. It will place you at the
+place you where when saving the object position and type information. Cross
+reference section <ref id="remember_ref">.
+
+<sect1>redraw
+<p>
+<tscreen><verb>
+Syntax: redraw
+</verb></tscreen>
+Sometimes the screen display gets corrupted. I still have problems with
+this. The <tt>redraw</> command simply redraws the entire display screen.
+
+<sect1><label id="remember_ref">remember
+<p>
+<tscreen><verb>
+Syntax: remember object
+</verb></tscreen>
+EXT2ED provides you <tt>memory</> of objects; While editing, you may reach an
+object which you will like to return to later. The <tt>remember</> command
+will store in memory the current place and type of the object. You can
+return to the object by using the <tt>recall</> command. Cross reference
+section <ref id="recall_ref">.
+
+<tt>Note:</>
+<itemize>
+<item> When remembering a <tt>file</> or a <tt>directory</>, the
+ corresponding inode will be saved in memory. The basic reason is that
+ the inode is essential for finding the blocks of the file or the
+ directory.
+</itemize>
+
+<sect1>set
+<p>
+<tscreen><verb>
+Syntax: set [text || hex] arg1 [arg2 arg3 ...]
+
+or
+
+Syntax: set variable=value
+</verb></tscreen>
+The <tt>set</> command is used to modify the current data.
+The <tt>set general command</> behavior is depended on whether you are editing a
+specific object, or none.
+
+<itemize>
+<item> In the case where Type is <tt>none</>, the first syntax should be
+ used. The set command affects the data starting at the current
+ highlighted position in the edited block.
+ <itemize>
+ <item> When using the <tt>set hex</> command, a list of
+ hexadecimal bytes should follow.
+ <item> When using the <tt>set text</> command, it should be followed
+ by a text string.
+ </itemize>
+ Examples:
+ <tscreen><verb>
+ set hex 09 0a 0b 0c 0d 0e 0f
+ set text Linux is just great !
+ </verb></tscreen>
+<item> In the case where Type is defined, the second syntax should be used.
+ The set commands just sets the variable <em>variable</> with the
+ value <em>value</>.
+</itemize>
+In any case, the data is only changed in memory. For an actual update to the
+disk, use the <tt>writedata</> command.
+
+<sect1>setdevice
+<p>
+<tscreen><verb>
+Syntax: setdevice device
+</verb></tscreen>
+The <tt>setdevice</> command is described at section <ref id="setdevice_ref">.
+
+<sect1>setoffset
+<p>
+<tscreen><verb>
+Syntax: setoffset [block || type] [+|-]offset
+</verb></tscreen>
+The <tt>setoffset</> command is used to move asynchronically inside the file
+system. It is considered a low level command, and usually should not be used
+when editing an ext2 filesystem, simply because movement is better
+utilized through the specific ext2 commands.
+
+The <tt>offset</> is in bytes, and meanwhile should be positive and smaller
+than 2GB.
+
+Use of the <tt>block</> modifier changes the counting unit to block.
+
+Use of the <tt>+ or -</> modifiers signals that the offset is relative to
+the current position.
+
+use of the <tt>type</> modifier is allowed only with relative offset. This
+modifier will multiply the offset by the size of the current type.
+
+<sect1>settype
+<p>
+<tscreen><verb>
+Syntax: settype type || [none | hex]
+</verb></tscreen>
+The <tt>settype</> command is used to move apply the object definitions of
+the type <em>type</> on the current position. It is considered a low level
+command and usually should not be used when editing an ext2 filesystem since
+EXT2ED provides better tools. It is of-course very useful when editing a
+non-ext2 filesystem and using user-defined objects.
+
+When <em>type</> is <em>hex</> or <em>none</>, the data will be displayed as
+a hex and text dump.
+
+<sect1>show
+<p>
+<tscreen><verb>
+Syntax: show
+</verb></tscreen>
+The <tt>show</> command will show the data of the current object at the
+current position on the main display window. It will also update the status
+window with type specific information. It may be necessary to use
+<tt>pgdn</> and <tt>pgup</> to view the entire data.
+
+<sect1>writedata
+<p>
+<tscreen><verb>
+Syntax: writedata
+</verb></tscreen>
+The <tt>writedata</> command will update the disk with the object data that
+is currently in memory. This is the point at which actual change is made to
+the filesystem. Without this command, the edited data will not have any
+effect. Write access should be allowed for a successful update.
+
+<sect>Editing an ext2 filesystem
+<p>
+
+In order to edit an ext2 filesystem, you should, of course, know the structure
+of the ext2 filesystem. If you feel that you lack some knowledge in this
+area, I suggest that you do some of the following:
+<itemize>
+<item> Read the supplied ext2 technical information. I tried to summarize
+ the basic information which is needed to get you started.
+<item> Get the slides that Remy Card (The author of the ext2 filesystem)
+ prepared concerning the ext2 filesystem.
+<item> Read the kernel sources.
+</itemize>
+At this point, you should be familiar with the following terms:
+<tt>block, inode, superblock, block groups, block allocation bitmap, inode
+allocation bitmap, group descriptors, file, directory.</>Most of the above
+are objects in EXT2ED.
+
+When editing an ext2 filesystem it is recommended that you use the ext2
+specific commands, rather then the general commands <tt>setoffset</> and
+<tt>settype</>, mainly because:
+<enum>
+<item> In most cases it will be unreliable, and will display incorrect
+ information.
+
+ Sometimes in order to edit an object, EXT2ED needs the information
+ of some other related objects. For example, when editing a
+ directory, EXT2ED needs access to the inode of the edited directory.
+ Simply setting the type to a directory <tt>will be unreliable</>,
+ since the object assumes that you passed through its inode to reach
+ it, and expects this information, which isn't initialized if you
+ directly set the type to a directory.
+<item> EXT2ED offers far better tools for handling the ext2 filesystem
+ using the ext2 specific commands.
+</enum>
+
+<sect>ext2 general commands
+<p>
+
+The <tt>ext2 general commands</> are available only when you are editing an
+ext2 filesystem. They are <tt>general</> in the sense that they are not
+specific to some object, and can be invoked anytime.
+
+<sect1><label id="general_superblock">super
+<p>
+<tscreen><verb>
+Syntax: super
+</verb></tscreen>
+The <tt>super</> command will "bring you" to the main superblock copy. It
+will automatically set the object type to <tt>ext2_super_block</>. Then you
+will be able to view and edit the superblock. When you are in the
+superblock, other commands will be available.
+
+<sect1>group
+<p>
+<tscreen><verb>
+Syntax: group [number]
+</verb></tscreen>
+The <tt>group</> command will "bring you" to the main copy of the
+<em>number</> group descriptor. It will automatically set the object type to
+<tt>ext2_group_desc</>. Then you will be able to view and edit the group
+descriptor entry. When you are there, other commands will be available.
+
+<sect1>cd
+<p>
+<tscreen><verb>
+Syntax: cd path
+</verb></tscreen>
+The <tt>cd</> command will let you travel in the filesystem in the nice way
+that the mounted filesystem would have let you.
+
+The <tt>cd</> command is a complicated command. Although it may sound
+simple at first, an implementation of a typical cd requires passing through
+the group descriptors, inodes, directory entries, etc. For example:
+
+The innocent cd /usr command can be done by using more primitive
+EXT2ED commands in the following way (It is implemented exactly this way):
+<enum>
+<item> Using <tt>group 0</> to go to the first group descriptor.
+<item> Using <tt>inode</> to get to the Bad blocks inode.
+<item> Using <tt>next</> to pass to the root directory inode.
+<item> Using <tt>dir</> to see the directory.
+<item> Using <tt>next</> until we find the directory usr.
+<item> Using <tt>followinode</> to pass to the inode corresponding to usr.
+<item> Using <tt>dir</> to see the directory of /usr.
+</enum>
+And those commands aren't that primitive; For example, the tracing of the
+blocks which belong to the root directory is done automatically by the dir
+command behind the scenes, and the followinode command will automatically
+"run" to the correct group descriptor in order to find the required inode.
+
+The path to the <tt>general cd</> command needs to be a full pathname -
+Starting from <tt>/</>. The <tt>cd</> command stops at the last reachable
+point, which can be a directory entry, in which case the type will be set to
+<tt>dir</>, or an inode, in which case the type will be set to
+<tt>ext2_inode</>. Symbolic links (Only fast symbolic links, meanwhile) are
+automatically followed (if they are not across filesystems, of-course). If
+the type is set to <tt>dir</>, you can use a path relative to the
+"current directory".
+
+<sect>The superblock
+<p>
+The superblock can always be reached by the ext2 general command
+<tt>super</>. Cross reference section <ref id="general_superblock">.
+
+The status window will show you which copy of the superblock copies you are
+currently editing.
+
+The main data window will show you the values of the various superblock
+variables, along with some interpretation of the values.
+
+Data can be changed with the <tt>set</> and <tt>writedata</> commands.
+<tscreen><verb>
+For example, set s_r_blocks_count=1400 will reserve 1400 blocks for root.
+</verb></tscreen>
+
+<sect1>gocopy
+<p>
+<tscreen><verb>
+Syntax: gocopy number
+</verb></tscreen>
+The <tt>gocopy</> command will "bring you" to the backup copy <em>number</>
+of the superblock copies. <tt>gocopy 0</>, for example, will bring you to
+the main copy.
+
+<sect1>setactivecopy
+<p>
+<tscreen><verb>
+Syntax: setactivecopy
+</verb></tscreen>
+The <tt>setactivecopy</> command will copy the contents of the current
+superblock copy onto the contents of the main copy. It will also switch to
+editing of the main copy. No actual data is written to disk, of-course,
+until you issue the <tt>writedata</> command.
+
+<sect>The group descriptors
+<p>
+The group descriptors can be edited by the <tt>group</> command.
+
+The status window will indicate the current group descriptor, the total
+number of group descriptors (and hence of group blocks), and the backup copy
+number.
+
+The main data window will just show you the values of the various variables.
+
+Basically, you can use the <tt>next</> and <tt>prev</> commands, along with the
+<tt>set</> command, to modify the group descriptors.
+
+The group descriptors object is a junction, from which you can reach:
+<itemize>
+<item> The inode table of the corresponding block group (the <tt>inode</>
+ command)
+<item> The block allocation bitmap (the <tt>blockbitmap</> command)
+<item> The inode allocation bitmap (the <tt>inodebitmap</> command)
+</itemize>
+
+<sect1>blockbitmap
+<p>
+<tscreen><verb>
+Syntax: blockbitmap
+</verb></tscreen>
+The <tt>blockbitmap</> command will let you edit the block bitmap allocation
+block of the current group block.
+
+<sect1>entry
+<p>
+<tscreen><verb>
+Syntax: entry number
+</verb></tscreen>
+The <tt>entry</> command will move you to the <em>number</> group descriptor in the
+group descriptors table.
+
+<sect1>inode
+<p>
+<tscreen><verb>
+Syntax: inode
+</verb></tscreen>
+The <tt>inode</> command will pass you to the first inode in the current
+group block.
+
+<sect1>inodebitmap
+<p>
+<tscreen><verb>
+Syntax: inodebitmap
+</verb></tscreen>
+The <tt>inodebitmap</> command will let you edit the inode bitmap allocation
+block of the current group block.
+
+<sect1>next
+<p>
+<tscreen><verb>
+Syntax: next [number]
+</verb></tscreen>
+The <tt>next</> command will pass to the next <em>number</> group
+descriptor. If <em>number</> is omitted, <em>number=1</> is assumed.
+
+<sect1>prev
+<p>
+<tscreen><verb>
+Syntax: prev [number]
+</verb></tscreen>
+The <tt>prev</> command will pass to the previous <em>number</> group
+descriptor. If <em>number</> is omitted, <em>number=1</> is assumed.
+
+<sect1>setactivecopy
+<p>
+<tscreen><verb>
+Syntax: setactivecopy
+</verb></tscreen>
+The <tt>setactivecopy</> command copies the contents of the current group
+descriptor, to its main copy. The updated main copy will then be shown. No
+actual change is made to the disk until you issue the <tt>writedata</>
+command.
+
+<sect>The inode
+<p>
+An inode can be reached by the following two ways:
+<itemize>
+<item> Using <tt>inode</> from the corresponding group descriptor.
+<item> Using <tt>followinode</> from a directory entry.
+<item> Using the <tt>cd</> command with the pathname to the file.
+
+ For example, <tt>cd /usr/src/ext2ed/ext2ed.h</>
+</itemize>
+
+The status window will indicate:
+<itemize>
+<item> The current global inode number.
+<item> The total total number of inodes.
+<item> On which block group the inode is allocated.
+<item> The total number of inodes in this group block.
+<item> The index of the current inode in the current group block.
+<item> The type of the inode (file, directory, special, etc).
+</itemize>
+
+The main data window, in addition to the list of variables, will contain
+some interpretations on the right side.
+
+If the inode corresponds to a file, you can use the <tt>file</> command to
+edit the file.
+
+If the inode is an inode of a directory, you can use the <tt>dir</> command
+to edit the directory.
+
+<sect1>dir
+<p>
+<tscreen><verb>
+Syntax: dir
+</verb></tscreen>
+If the inode mode corresponds to a directory (shown on the status window),
+you can enter directory mode editing by using <tt>dir</>.
+
+<sect1>entry
+<p>
+<tscreen><verb>
+Syntax: entry number
+</verb></tscreen>
+The <tt>entry</> command will move you to the <em>number</> inode in the
+current inode table.
+
+<sect1>file
+<p>
+<tscreen><verb>
+Syntax: file
+</verb></tscreen>
+If the inode mode corresponds to a file (shown on the status window),
+you can enter file mode editing by using <tt>file</>.
+
+<sect1>group
+<p>
+<tscreen><verb>
+Syntax: group
+</verb></tscreen>
+The <tt>group</> command is used to go to the group descriptor of the
+current group block.
+
+<sect1>next
+<p>
+<tscreen><verb>
+Syntax: next [number]
+</verb></tscreen>
+The <tt>next</> command will pass to the next <em>number</> inode.
+If <em>number</> is omitted, <em>number=1</> is assumed.
+
+<sect1>prev
+<p>
+<tscreen><verb>
+Syntax: prev [number]
+</verb></tscreen>
+The <tt>prev</> command will pass to the previous <em>number</> inode.
+If <em>number</> is omitted, <em>number=1</> is assumed.
+
+<sect>The file
+<p>
+When editing a file, EXT2ED offers you a both a continuous and a true
+fragmented view of the file - The file is still shown block by block with
+the true block number at each stage and EXT2ED offers you commands which
+allow you to move between the <tt>file blocks</>, while finding the
+allocated blocks by using the inode information behind the scenes.
+
+Aside from this, the editing is just a <tt>hex editing</> - You move the
+cursor in the current block of the file by using <tt>next</> and
+<tt>prev</>, move between blocks by <tt>nextblock</> and <tt>prevblock</>,
+and make changes by the <tt>set</> command. Note that the set command is
+overridden here - There are no variables. The <tt>writedata</> command will
+update the current block to the disk.
+
+Reaching a file can be done by using the <tt>file</> command from its inode.
+The <tt>inode</> can be reached by any other means, for example, by the
+<tt>cd</> command, if you know the file name.
+
+The status window will indicate:
+<itemize>
+<item> The global block number.
+<item> The internal file block number.
+<item> The file offset.
+<item> The file size.
+<item> The file inode number.
+<item> The indirection level - Whether it is a direct block (0), indirect
+ (1), etc.
+</itemize>
+
+The main data window will display the file either in hex mode or in text
+mode, select-able by the <tt>display</> command.
+
+In hex mode, EXT2ED will display offsets in the current block, along with a
+text and hex dump of the current block.
+
+In either case the <tt>current place</> will be highlighted. In the hex mode
+it will be always highlighted, while in the text mode it will be highlighted
+if the character is display-able.
+
+<sect1>block
+<p>
+<tscreen><verb>
+Syntax: block block_num
+</verb></tscreen>
+The <tt>block</> command is used to move inside the file. The
+<em>block_num</> argument is the requested internal file block number. A
+value of 0 will reach the beginning of the file.
+
+<sect1>display
+<p>
+<tscreen><verb>
+Syntax: display [text || hex]
+</verb></tscreen>
+The <tt>display</> command changes the display mode of the file. <tt>display
+hex</> will switch to <tt>hex mode</>, while <tt>display text</> will switch
+to text mode. The default mode when no <tt>display</> command is issued is
+<tt>hex mode</>.
+
+<sect1>inode
+<p>
+<tscreen><verb>
+Syntax: inode
+</verb></tscreen>
+The <tt>inode</> command will return to the inode of the current file.
+
+<sect1>next
+<p>
+<tscreen><verb>
+Syntax: next [num]
+</verb></tscreen>
+The <tt>next</> command will pass to the next byte in the file. If
+<em>num</> is supplied, it will pass to the next <em>num</> bytes.
+
+<sect1>nextblock
+<p>
+<tscreen><verb>
+Syntax: nextblock [num]
+</verb></tscreen>
+The <tt>nextblock</> command will pass to the next block in the file. If
+<em>num</> is supplied, it will pass to the next <em>num</> blocks.
+
+<sect1>prev
+<p>
+<tscreen><verb>
+Syntax: prev [num]
+</verb></tscreen>
+The <tt>prev</> command will pass to the previous byte in the file. If
+<em>num</> is supplied, it will pass to the previous <em>num</> bytes.
+
+<sect1>prevblock
+<p>
+<tscreen><verb>
+Syntax: prevblock [num]
+</verb></tscreen>
+The <tt>nextblock</> command will pass to the previous block in the file. If
+<em>num</> is supplied, it will pass to the previous <em>num</> blocks.
+
+<sect1>offset
+<p>
+<tscreen><verb>
+Syntax: offset file_offset
+</verb></tscreen>
+The <tt>offset</> command will move to the specified offset in the file.
+
+<sect1>set
+<p>
+<tscreen><verb>
+Syntax: set [text || hex] arg1 [arg2 arg3 ...]
+</verb></tscreen>
+The <tt>file set</> command is working like the <tt>general set command</>,
+with <tt>type=none</>. There are no variables.
+
+<sect1>writedata
+<p>
+<tscreen><verb>
+Syntax: writedata
+</verb></tscreen>
+The <tt>writedata</> command will update the current file block in the disk.
+
+<sect>The directory
+<p>
+When editing a file, EXT2ED analyzes for you both the allocation blocks of
+the directory entries, and the directory entries.
+
+Each directory entry is displayed on one row. You can move the highlighted
+entry with the usual <tt>next</> and <tt>prev</> commands, and "dive in"
+with the <tt>followinode</> command.
+
+The status window will indicate:
+<itemize>
+<item> The directory entry number.
+<item> The total number of directory entries in this directory.
+<item> The current global block number.
+<item> The current offset in the entire directory - When viewing the
+ directory as a continuous file.
+<item> The inode number of the directory itself.
+<item> The indirection level - Whether it is a direct block (0), indirect
+ (1), etc.
+</itemize>
+
+<sect1>cd
+<p>
+<tscreen><verb>
+Syntax: cd [path]
+</verb></tscreen>
+The <tt>cd</> command is used in the usual meaning, like the global cd
+command.
+<itemize>
+<item> If <em>path</> is not specified, the current directory entry is
+ followed.
+<item> <em>path</> can be relative to the current directory.
+<item> <em>path</> can also end up in a file, in which case the file inode
+ will be reached.
+<item> Symbolic link (fast only, meanwhile) is automatically followed.
+</itemize>
+
+<sect1>entry
+<p>
+<tscreen><verb>
+Syntax: entry [entry_num]
+</verb></tscreen>
+The <tt>entry</> command sets <em>entry_num</> as the current directory
+entry.
+
+<sect1>followinode
+<p>
+<tscreen><verb>
+Syntax: followinode
+</verb></tscreen>
+The <tt>followinode</> command will move you to the inode pointed by the
+current directory entry.
+
+<sect1>inode
+<p>
+<tscreen><verb>
+Syntax: inode
+</verb></tscreen>
+The <tt>inode</> command will return you to the parent inode of the whole
+directory listing.
+
+<sect1>next
+<p>
+<tscreen><verb>
+Syntax: next [num]
+</verb></tscreen>
+The <tt>next</> command will pass to the next directory entry.
+If <em>num</> is supplied, it will pass to the next <em>num</> entries.
+
+<sect1>prev
+<p>
+<tscreen><verb>
+Syntax: prev [num]
+</verb></tscreen>
+The <tt>prev</> command will pass to the previous directory entry.
+If <em>num</> is supplied, it will pass to the previous <em>num</> entries.
+
+<sect1>writedata
+<p>
+<tscreen><verb>
+Syntax: writedata
+</verb></tscreen>
+The <tt>writedata</> command will write the current directory entry to the
+disk.
+
+<sect><label id="block_bitmap">The block allocation bitmap
+<p>
+The <tt>block allocation bitmap</> of any block group can be reached from
+the corresponding group descriptor.
+
+You will be offered a bit listing of the entire blocks in the group. The
+current block will be highlighted and its number will be displayed in the
+status window.
+
+A value of "1" means that the block is allocated, while a value of "0"
+signals that it is free. The value is also interpreted in the status
+window. You can use the usual <tt>next/prev</> commands, along with the
+<tt>allocate/deallocate</> commands.
+
+<sect1>allocate
+<p>
+<tscreen><verb>
+Syntax: allocate [num]
+</verb></tscreen>
+The <tt>allocate</> command allocates <em>num</> blocks, starting from the
+highlighted position. If <em>num</> is not specified, <em>num=1</> is assumed.
+Of-course, no actual change is made until you issue a <tt>writedata</> command.
+
+<sect1>deallocate
+<p>
+<tscreen><verb>
+Syntax: deallocate [num]
+</verb></tscreen>
+The <tt>deallocate</> command deallocates <em>num</> blocks, starting from the
+highlighted position. If <em>num</> is not specified, <em>num=1</> is assumed.
+Of-course, no actual change is made until you issue a <tt>writedata</> command.
+<tt>writedata</> command.
+
+<sect1>entry
+<p>
+<tscreen><verb>
+Syntax: entry [entry_num]
+</verb></tscreen>
+The <tt>entry</> command sets the current highlighted block to
+<em>entry_num</>.
+
+<sect1>next
+<p>
+<tscreen><verb>
+Syntax: next [num]
+</verb></tscreen>
+The <tt>next</> command will pass to the next bit, which corresponds to the
+next block. If <em>num</> is supplied, it will pass to the next <em>num</>
+bits.
+
+<sect1>prev
+<p>
+<tscreen><verb>
+Syntax: prev [num]
+</verb></tscreen>
+The <tt>prev</> command will pass to the previous bit, which corresponds to the
+previous block. If <em>num</> is supplied, it will pass to the previous
+<em>num</> bits.
+
+<sect>The inode allocation bitmap
+<p>
+
+The <tt>inode allocation bitmap</> is very similar to the block allocation
+bitmap explained above. It is also reached from the corresponding group
+descriptor. Please refer to section <ref id="block_bitmap">.
+
+<sect>Filesystem size limitation
+<p>
+
+While an ext2 filesystem has a size limit of <tt>4 TB</>, EXT2ED currently
+<tt>can't</> handle filesystems which are <tt>bigger than 2 GB</>.
+
+I am sorry for the inconvenience. This will hopefully be fixed in future
+releases.
+
+<sect>Copyright
+<p>
+
+EXT2ED is Copyright (C) 1995 Gadi Oxman.
+
+EXT2ED is hereby placed under the GPL - Gnu Public License. You are free and
+welcome to copy, view and modify the sources. My only wish is that my
+copyright presented above will be left and that a list of the bug fixes,
+added features, etc, will be provided.
+
+The entire EXT2ED project is based, of-course, on the kernel sources. The
+<tt>ext2.descriptors</> distributed with EXT2ED is a slightly modified
+version of the main ext2 include file, /usr/include/linux/ext2_fs.h. Follows
+the original copyright:
+
+<tscreen><verb>
+/*
+ * linux/include/linux/ext2_fs.h
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/include/linux/minix_fs.h
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+</verb></tscreen>
+
+<sect>Acknowledgments
+<p>
+
+EXT2ED was constructed as a student project in the software
+laboratory of the faculty of electrical-engineering in the
+<tt>Technion - Israel's institute of technology</>.
+
+At first, I would like to thank <tt>Avner Lottem</> and <tt>Doctor Ilana
+David</> for their interest and assistance in this project.
+
+I would also like to thank the following people, who were involved in the
+design and implementation of the ext2 filesystem kernel code and support
+utilities:
+<itemize>
+<item> <tt>Remy Card</>
+
+ Who designed, implemented and maintains the ext2 filesystem kernel
+ code, and some of the ext2 utilities. Remy Card is also the author
+ of several helpful slides concerning the ext2 filesystem.
+ Specifically, he is the author of <tt>File Management in the Linux
+ Kernel</> and of <tt>The Second Extended File System - Current State,
+ Future Development</>.
+
+<item> <tt>Wayne Davison</>
+
+ Who designed the ext2 filesystem.
+<item> <tt>Stephen Tweedie</>
+
+ Who helped designing the ext2 filesystem kernel code and wrote the
+ slides <tt>Optimizations in File Systems</>.
+<item> <tt>Theodore Ts'o</>
+
+ Who is the author of several ext2 utilities and of the ext2 library
+ <tt>libext2fs</> (which I didn't use, simply because I didn't know
+ it exists when I started to work on my project).
+</itemize>
+
+Lastly, I would like to thank, of-course, <tt>Linus Torvalds</> and the
+<tt>Linux community</> for providing all of us with such a great operating
+system.
+
+Please contact me in a case of bug report, suggestions, or just about
+anything concerning EXT2ED.
+
+Enjoy,
+
+Gadi Oxman &lt;tgud@tochnapc2.technion.ac.il&gt;
+
+Haifa, August 95
+</article> \ No newline at end of file
diff --git a/ext2ed/ext2.descriptors b/ext2ed/ext2.descriptors
new file mode 100644
index 00000000..9d107faa
--- /dev/null
+++ b/ext2ed/ext2.descriptors
@@ -0,0 +1,407 @@
+Extended 2 filesystem structure definitions for ext2ed.
+
+Most of this file is just copied from the ext2 main include file.
+
+My parser is very primitive - It only searches for the struct keywords,
+and uses the variables in there. The rest of the file is just ignored.
+
+You will find at the end a few additional types which are not aviable in
+the original include file, such as the types "file" and "dir". They have
+no variables, but are necessary due to the way ext2ed binds C commands
+to specific types.
+
+Gadi Oxman, 7/95
+
+Here is the original copyright:
+
+/*
+ * linux/include/linux/ext2_fs.h
+ *
+ * Copyright (C) 1992, 1993, 1994 Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/include/linux/minix_fs.h
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+
+/*
+ * ACL structures
+ */
+struct ext2_acl_header /* Header of Access Control Lists */
+{
+ unsigned long aclh_size;
+ unsigned long aclh_file_count;
+ unsigned long aclh_acle_count;
+ unsigned long aclh_first_acle;
+};
+
+struct ext2_acl_entry /* Access Control List Entry */
+{
+ unsigned long acle_size;
+ unsigned short acle_perms; /* Access permissions */
+ unsigned short acle_type; /* Type of entry */
+ unsigned short acle_tag; /* User or group identity */
+ unsigned short acle_pad1;
+ unsigned long acle_next; /* Pointer on next entry for the */
+ /* same inode or on next free entry */
+};
+
+/*
+ * Structure of a blocks group descriptor
+ */
+
+struct ext2_group_desc
+{
+ unsigned long bg_block_bitmap; /* Blocks bitmap block */
+ unsigned long bg_inode_bitmap; /* Inodes bitmap block */
+ unsigned long bg_inode_table; /* Inodes table block */
+ unsigned short bg_free_blocks_count; /* Free blocks count */
+ unsigned short bg_free_inodes_count; /* Free inodes count */
+ unsigned short bg_used_dirs_count; /* Directories count */
+ unsigned short bg_pad;
+ unsigned long bg_reserved[0];
+ unsigned long bg_reserved[1];
+ unsigned long bg_reserved[2];
+};
+
+/*
+ * Structure of an inode on the disk
+ */
+struct ext2_inode {
+ unsigned short i_mode; /* File mode */
+ unsigned short i_uid; /* Owner Uid */
+ unsigned long i_size; /* Size in bytes */
+ unsigned long i_atime; /* Access time */
+ unsigned long i_ctime; /* Creation time */
+ unsigned long i_mtime; /* Modification time */
+ unsigned long i_dtime; /* Deletion Time */
+ unsigned short i_gid; /* Group Id */
+ unsigned short i_links_count; /* Links count */
+ unsigned long i_blocks; /* Blocks count */
+ unsigned long i_flags; /* File flags */
+ unsigned long l_i_reserved1;
+ unsigned long i_block[0]; /* Pointers to blocks */
+ unsigned long i_block[1]; /* Pointers to blocks */
+ unsigned long i_block[2]; /* Pointers to blocks */
+ unsigned long i_block[3]; /* Pointers to blocks */
+ unsigned long i_block[4]; /* Pointers to blocks */
+ unsigned long i_block[5]; /* Pointers to blocks */
+ unsigned long i_block[6]; /* Pointers to blocks */
+ unsigned long i_block[7]; /* Pointers to blocks */
+ unsigned long i_block[8]; /* Pointers to blocks */
+ unsigned long i_block[9]; /* Pointers to blocks */
+ unsigned long i_block[10]; /* Pointers to blocks */
+ unsigned long i_block[11]; /* Pointers to blocks */
+ unsigned long i_block[12]; /* Pointers to blocks */
+ unsigned long i_block[13]; /* Pointers to blocks */
+ unsigned long i_block[14]; /* Pointers to blocks */
+ unsigned long i_version; /* File version (for NFS) */
+ unsigned long i_file_acl; /* File ACL */
+ unsigned long i_dir_acl; /* Directory ACL */
+ unsigned long i_faddr; /* Fragment address */
+ unsigned char l_i_frag; /* Fragment number */
+ unsigned char l_i_fsize; /* Fragment size */
+ unsigned short i_pad1;
+ unsigned long l_i_reserved2[0];
+ unsigned long l_i_reserved2[1];
+};
+
+/*
+ * Structure of the super block
+ */
+struct ext2_super_block {
+ unsigned long s_inodes_count; /* Inodes count */
+ unsigned long s_blocks_count; /* Blocks count */
+ unsigned long s_r_blocks_count; /* Reserved blocks count */
+ unsigned long s_free_blocks_count; /* Free blocks count */
+ unsigned long s_free_inodes_count; /* Free inodes count */
+ unsigned long s_first_data_block; /* First Data Block */
+ unsigned long s_log_block_size; /* Block size */
+ long s_log_frag_size; /* Fragment size */
+ unsigned long s_blocks_per_group; /* # Blocks per group */
+ unsigned long s_frags_per_group; /* # Fragments per group */
+ unsigned long s_inodes_per_group; /* # Inodes per group */
+ unsigned long s_mtime; /* Mount time */
+ unsigned long s_wtime; /* Write time */
+ unsigned short s_mnt_count; /* Mount count */
+ short s_max_mnt_count; /* Maximal mount count */
+ unsigned short s_magic; /* Magic signature */
+ unsigned short s_state; /* File system state */
+ unsigned short s_errors; /* Behaviour when detecting errors */
+ unsigned short s_pad;
+ unsigned long s_lastcheck; /* time of last check */
+ unsigned long s_checkinterval; /* max. time between checks */
+ unsigned long s_creator_os; /* OS */
+ unsigned long s_rev_level; /* Revision level */
+ unsigned short s_def_resuid;
+ unsigned short s_deg_resgid;
+
+ unsigned long s_reserved[0]; /* Padding to the end of the block */
+ unsigned long s_reserved[1];
+ unsigned long s_reserved[2];
+ unsigned long s_reserved[3];
+ unsigned long s_reserved[4];
+ unsigned long s_reserved[5];
+ unsigned long s_reserved[6];
+ unsigned long s_reserved[7];
+ unsigned long s_reserved[8];
+ unsigned long s_reserved[9];
+ unsigned long s_reserved[10];
+ unsigned long s_reserved[11];
+ unsigned long s_reserved[12];
+ unsigned long s_reserved[13];
+ unsigned long s_reserved[14];
+ unsigned long s_reserved[15];
+ unsigned long s_reserved[16];
+ unsigned long s_reserved[17];
+ unsigned long s_reserved[18];
+ unsigned long s_reserved[19];
+ unsigned long s_reserved[20];
+ unsigned long s_reserved[21];
+ unsigned long s_reserved[22];
+ unsigned long s_reserved[23];
+ unsigned long s_reserved[24];
+ unsigned long s_reserved[25];
+ unsigned long s_reserved[26];
+ unsigned long s_reserved[27];
+ unsigned long s_reserved[28];
+ unsigned long s_reserved[29];
+ unsigned long s_reserved[30];
+ unsigned long s_reserved[31];
+ unsigned long s_reserved[32];
+ unsigned long s_reserved[33];
+ unsigned long s_reserved[34];
+ unsigned long s_reserved[35];
+ unsigned long s_reserved[36];
+ unsigned long s_reserved[37];
+ unsigned long s_reserved[38];
+ unsigned long s_reserved[39];
+ unsigned long s_reserved[40];
+ unsigned long s_reserved[41];
+ unsigned long s_reserved[42];
+ unsigned long s_reserved[43];
+ unsigned long s_reserved[44];
+ unsigned long s_reserved[45];
+ unsigned long s_reserved[46];
+ unsigned long s_reserved[47];
+ unsigned long s_reserved[48];
+ unsigned long s_reserved[49];
+ unsigned long s_reserved[50];
+ unsigned long s_reserved[51];
+ unsigned long s_reserved[52];
+ unsigned long s_reserved[53];
+ unsigned long s_reserved[54];
+ unsigned long s_reserved[55];
+ unsigned long s_reserved[56];
+ unsigned long s_reserved[57];
+ unsigned long s_reserved[58];
+ unsigned long s_reserved[59];
+ unsigned long s_reserved[60];
+ unsigned long s_reserved[61];
+ unsigned long s_reserved[62];
+ unsigned long s_reserved[63];
+ unsigned long s_reserved[64];
+ unsigned long s_reserved[65];
+ unsigned long s_reserved[66];
+ unsigned long s_reserved[67];
+ unsigned long s_reserved[68];
+ unsigned long s_reserved[69];
+ unsigned long s_reserved[70];
+ unsigned long s_reserved[71];
+ unsigned long s_reserved[72];
+ unsigned long s_reserved[73];
+ unsigned long s_reserved[74];
+ unsigned long s_reserved[75];
+ unsigned long s_reserved[76];
+ unsigned long s_reserved[77];
+ unsigned long s_reserved[78];
+ unsigned long s_reserved[79];
+ unsigned long s_reserved[80];
+ unsigned long s_reserved[81];
+ unsigned long s_reserved[82];
+ unsigned long s_reserved[83];
+ unsigned long s_reserved[84];
+ unsigned long s_reserved[85];
+ unsigned long s_reserved[86];
+ unsigned long s_reserved[87];
+ unsigned long s_reserved[88];
+ unsigned long s_reserved[89];
+ unsigned long s_reserved[90];
+ unsigned long s_reserved[91];
+ unsigned long s_reserved[92];
+ unsigned long s_reserved[93];
+ unsigned long s_reserved[94];
+ unsigned long s_reserved[95];
+ unsigned long s_reserved[96];
+ unsigned long s_reserved[97];
+ unsigned long s_reserved[98];
+ unsigned long s_reserved[99];
+ unsigned long s_reserved[100];
+ unsigned long s_reserved[101];
+ unsigned long s_reserved[102];
+ unsigned long s_reserved[103];
+ unsigned long s_reserved[104];
+ unsigned long s_reserved[105];
+ unsigned long s_reserved[106];
+ unsigned long s_reserved[107];
+ unsigned long s_reserved[108];
+ unsigned long s_reserved[109];
+ unsigned long s_reserved[110];
+ unsigned long s_reserved[111];
+ unsigned long s_reserved[112];
+ unsigned long s_reserved[113];
+ unsigned long s_reserved[114];
+ unsigned long s_reserved[115];
+ unsigned long s_reserved[116];
+ unsigned long s_reserved[117];
+ unsigned long s_reserved[118];
+ unsigned long s_reserved[119];
+ unsigned long s_reserved[120];
+ unsigned long s_reserved[121];
+ unsigned long s_reserved[122];
+ unsigned long s_reserved[123];
+ unsigned long s_reserved[124];
+ unsigned long s_reserved[125];
+ unsigned long s_reserved[126];
+ unsigned long s_reserved[127];
+ unsigned long s_reserved[128];
+ unsigned long s_reserved[129];
+ unsigned long s_reserved[130];
+ unsigned long s_reserved[131];
+ unsigned long s_reserved[132];
+ unsigned long s_reserved[133];
+ unsigned long s_reserved[134];
+ unsigned long s_reserved[135];
+ unsigned long s_reserved[136];
+ unsigned long s_reserved[137];
+ unsigned long s_reserved[138];
+ unsigned long s_reserved[139];
+ unsigned long s_reserved[140];
+ unsigned long s_reserved[141];
+ unsigned long s_reserved[142];
+ unsigned long s_reserved[143];
+ unsigned long s_reserved[144];
+ unsigned long s_reserved[145];
+ unsigned long s_reserved[146];
+ unsigned long s_reserved[147];
+ unsigned long s_reserved[148];
+ unsigned long s_reserved[149];
+ unsigned long s_reserved[150];
+ unsigned long s_reserved[151];
+ unsigned long s_reserved[152];
+ unsigned long s_reserved[153];
+ unsigned long s_reserved[154];
+ unsigned long s_reserved[155];
+ unsigned long s_reserved[156];
+ unsigned long s_reserved[157];
+ unsigned long s_reserved[158];
+ unsigned long s_reserved[159];
+ unsigned long s_reserved[160];
+ unsigned long s_reserved[161];
+ unsigned long s_reserved[162];
+ unsigned long s_reserved[163];
+ unsigned long s_reserved[164];
+ unsigned long s_reserved[165];
+ unsigned long s_reserved[166];
+ unsigned long s_reserved[167];
+ unsigned long s_reserved[168];
+ unsigned long s_reserved[169];
+ unsigned long s_reserved[170];
+ unsigned long s_reserved[171];
+ unsigned long s_reserved[172];
+ unsigned long s_reserved[173];
+ unsigned long s_reserved[174];
+ unsigned long s_reserved[175];
+ unsigned long s_reserved[176];
+ unsigned long s_reserved[177];
+ unsigned long s_reserved[178];
+ unsigned long s_reserved[179];
+ unsigned long s_reserved[180];
+ unsigned long s_reserved[181];
+ unsigned long s_reserved[182];
+ unsigned long s_reserved[183];
+ unsigned long s_reserved[184];
+ unsigned long s_reserved[185];
+ unsigned long s_reserved[186];
+ unsigned long s_reserved[187];
+ unsigned long s_reserved[188];
+ unsigned long s_reserved[189];
+ unsigned long s_reserved[190];
+ unsigned long s_reserved[191];
+ unsigned long s_reserved[192];
+ unsigned long s_reserved[193];
+ unsigned long s_reserved[194];
+ unsigned long s_reserved[195];
+ unsigned long s_reserved[196];
+ unsigned long s_reserved[197];
+ unsigned long s_reserved[198];
+ unsigned long s_reserved[199];
+ unsigned long s_reserved[200];
+ unsigned long s_reserved[201];
+ unsigned long s_reserved[202];
+ unsigned long s_reserved[203];
+ unsigned long s_reserved[204];
+ unsigned long s_reserved[205];
+ unsigned long s_reserved[206];
+ unsigned long s_reserved[207];
+ unsigned long s_reserved[208];
+ unsigned long s_reserved[209];
+ unsigned long s_reserved[210];
+ unsigned long s_reserved[211];
+ unsigned long s_reserved[212];
+ unsigned long s_reserved[213];
+ unsigned long s_reserved[214];
+ unsigned long s_reserved[215];
+ unsigned long s_reserved[216];
+ unsigned long s_reserved[217];
+ unsigned long s_reserved[218];
+ unsigned long s_reserved[219];
+ unsigned long s_reserved[220];
+ unsigned long s_reserved[221];
+ unsigned long s_reserved[222];
+ unsigned long s_reserved[223];
+ unsigned long s_reserved[224];
+ unsigned long s_reserved[225];
+ unsigned long s_reserved[226];
+ unsigned long s_reserved[227];
+ unsigned long s_reserved[228];
+ unsigned long s_reserved[229];
+ unsigned long s_reserved[230];
+ unsigned long s_reserved[231];
+ unsigned long s_reserved[232];
+ unsigned long s_reserved[233];
+ unsigned long s_reserved[234];
+};
+
+The following is actually not used, due to the variable length of the
+name field. EXT2ED handles directories through the type "dir" below.
+
+/*
+ * Structure of a directory entry
+ */
+
+/* struct ext2_dir_entry { */
+/*
+ unsigned long inode; /* Inode number */
+ unsigned short rec_len; /* Directory entry length */
+ unsigned short name_len; /* Name length */
+ char name[EXT2_NAME_LEN]; /* File name */
+};
+*/
+
+struct file {
+};
+
+struct dir {
+};
+
+struct block_bitmap {
+};
+
+struct inode_bitmap {
+};
diff --git a/ext2ed/ext2_com.c b/ext2ed/ext2_com.c
new file mode 100644
index 00000000..b4d2a661
--- /dev/null
+++ b/ext2ed/ext2_com.c
@@ -0,0 +1,97 @@
+/*
+
+/usr/src/ext2ed/ext2_com.c
+
+A part of the extended file system 2 disk editor.
+
+--------------------------------------
+Extended-2 filesystem General commands
+--------------------------------------
+
+The commands here will be registered when we are editing an ext2 filesystem
+
+First written on: July 28 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+void type_ext2___super (char *command_line)
+
+/*
+
+We are moving to the superblock - Just use setoffset and settype. The offset was gathered in the
+initialization phase (but is constant - 1024).
+
+*/
+
+{
+ char buffer [80];
+
+ super_info.copy_num=0;
+ sprintf (buffer,"setoffset %ld",file_system_info.super_block_offset);dispatch (buffer);
+ sprintf (buffer,"settype ext2_super_block");dispatch (buffer);
+}
+
+void type_ext2___cd (char *command_line)
+
+/*
+
+A global cd command - The path should start with /.
+
+We implement it through dispatching to our primitive functions.
+
+*/
+
+{
+ char temp [80],buffer [80],*ptr;
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return;
+ }
+ ptr=parse_word (ptr,buffer);
+
+ if (buffer [0] != '/') {
+ wprintw (command_win,"Error - Use a full pathname (begin with '/')\n");refresh_command_win ();return;
+ }
+
+ /* Note the various dispatches below - They should be intuitive if you know the ext2 filesystem structure */
+
+ dispatch ("super");dispatch ("group");dispatch ("inode");dispatch ("next");dispatch ("dir");
+ if (buffer [1] != 0) {
+ sprintf (temp,"cd %s",buffer+1);dispatch (temp);
+ }
+}
+
+void type_ext2___group (char *command_line)
+
+/*
+
+We go to the group descriptors.
+First, we go to the first group descriptor in the main copy.
+Then, we use the group's entry command to pass to another group.
+
+*/
+
+{
+ long group_num=0;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ group_num=atol (buffer);
+ }
+
+ group_info.copy_num=0;group_info.group_num=0;
+ sprintf (buffer,"setoffset %ld",file_system_info.first_group_desc_offset);dispatch (buffer);
+ sprintf (buffer,"settype ext2_group_desc");dispatch (buffer);
+ sprintf (buffer,"entry %ld",group_num);dispatch (buffer);
+}
diff --git a/ext2ed/ext2ed.conf b/ext2ed/ext2ed.conf
new file mode 100644
index 00000000..4754d1ca
--- /dev/null
+++ b/ext2ed/ext2ed.conf
@@ -0,0 +1,79 @@
+##############################################################################
+# ext2ed.conf #
+# #
+# Configuration file for the extended 2 file system disk editor. #
+##############################################################################
+
+# Ext2Descriptors is the location of the ext2 filesystem structure
+# definitions.
+
+
+Ext2Descriptors /var/lib/ext2ed/ext2.descriptors
+
+
+# Using AlternateDescriptors you can declare additional structures. Those
+# structures can contain only variables. Linking functions to the objects is
+# possible only through source code additions.
+
+
+AlternateDescriptors
+
+
+# LogFile is the location of the log file. Actual changes to the filesystem
+# are logged there. See also LogChanges.
+
+
+LogFile /var/lib/ext2ed/ext2ed.log
+
+
+# The following selects the default behavior when changes are made to the
+# filesystem. When on, each change will be logged - Both the previous data
+# and the new written data.
+
+
+LogChanges on
+
+
+# AllowChanges off will not allow ext2ed to do any changes to the
+# filesystem - The "enablewrite" command will not work. When on, enablewrite
+# will still have to be issued to allow write access.
+
+
+AllowChanges on
+
+
+# With this option you can choose whether ext2ed will allow read-only mode on
+# a mounted filesystem. Read-Write mode is never allowed on a mounted
+# filesystem.
+
+
+AllowMountedRead on
+
+
+# When ForceExt2 is set to on, the filesystem is assumed to be ext2
+# filesystem, despite the possibly corrupt superblock magic number reading.
+# All the ext2 specific commands will be aviable despite the possible
+# autodetection failture.
+
+ForceExt2 off
+
+
+# Normally, the various filesystem parameters such as the block size and the
+# total number of blocks are gathered from the ext2 filesystem itself.
+# However, on a corrupt filesystem, ext2ed is unable to get the right
+# parameters. In this case, they will be taken from here. See also
+# ForceDefault.
+
+
+DefaultBlockSize 1024
+DefaultTotalBlocks 2097151 # ~2 GB total size
+DefaultBlocksInGroup 8192
+
+# With ForceDefault on, you can force the use of the default parameters
+# above. This is not recommended, as ext2ed will fallback by default to those
+# parameters if it can't figure up the parameters from the filesystem itself.
+
+
+ForceDefault off
+
+
diff --git a/ext2ed/ext2ed.h b/ext2ed/ext2ed.h
new file mode 100644
index 00000000..34d836f2
--- /dev/null
+++ b/ext2ed/ext2ed.h
@@ -0,0 +1,438 @@
+
+/*
+
+/usr/src/ext2ed/ext2ed.h
+
+A part of the extended file system 2 disk editor.
+
+--------------------------------------
+Include file for the ext2 disk editor.
+--------------------------------------
+
+This file contains declarations which are needed by all the files in ext2ed.
+
+First written on: April 9 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#ifndef EXT2ED_EDITOR_H
+#define EXT2ED_EDITOR_H
+
+/*
+
+-----------------------
+ User definable options
+-----------------------
+
+*/
+
+#ifndef VAR_DIR
+ #define VAR_DIR "/var/lib/ext2ed" /* The configuration file will be searched here */
+#endif
+
+#define DEBUG /* Activate self-sanity checks */
+
+#include <linux/ext2_fs.h> /* Main kernel ext2 include file */
+#include <linux/stat.h>
+
+#ifdef OLD_NCURSES /* The ncurses interface */
+ #include <ncurses/ncurses.h>
+#else
+ #include <ncurses/curses.h>
+#endif
+
+#define MAX_FIELDS 400
+
+#define MAX_COMMAND_LINE 81
+#define MAX_COMMANDS_NUM 30 /* Maximum number of commands of one type */
+#define REMEMBER_COUNT 30 /* Object memory size */
+
+/*
+ The user screen consists of four parts:
+
+ 1. Title window (title_win).
+ 2. Show (status) window (show_win).
+ 3. Main show pad (show_pad).
+ 4. Command window (command_win).
+
+*/
+
+/*
+
+ The show pad is mapped to the space left between the other three windows.
+
+ If you wondered why ext2ed grabs so memory, the answer is probably below - I wanted to treat
+ the virtual display as infinite. Decrease the following for more realistic memory consumption.
+
+*/
+
+#define SHOW_PAD_LINES 3000
+#define SHOW_PAD_COLS (COLS > 140 ? COLS : 140)
+
+#define COMMAND_WIN_LINES 6 /* Change this to your preferences */
+#define TITLE_WIN_LINES 3
+#define SHOW_WIN_LINES 3
+
+#define HEX 1
+#define TEXT 2
+
+#ifndef EXT2_PRE_02B_MAGIC
+ #define EXT2_PRE_02B_MAGIC 0xEF51
+#endif
+
+
+typedef void (*PF) (char *); /* Used to point to the dispatched functions */
+
+struct struct_commands { /* Holds commands of an object */
+ int last_command;
+ char *names [MAX_COMMANDS_NUM];
+ char *descriptions [MAX_COMMANDS_NUM];
+ PF callback [MAX_COMMANDS_NUM];
+};
+
+struct struct_descriptor { /* Describes an object */
+ unsigned long length;
+ unsigned char name [60];
+ unsigned short fields_num;
+ unsigned char field_names [MAX_FIELDS][80];
+ unsigned short field_lengths [MAX_FIELDS];
+ unsigned short field_positions [MAX_FIELDS];
+ struct struct_commands type_commands;
+ struct struct_descriptor *prev,*next;
+};
+
+struct struct_type_data { /* The object's data is usually here */
+ long offset_in_block;
+
+ union union_type_data { /* Format it in various ways */
+ char buffer [EXT2_MAX_BLOCK_SIZE];
+ struct ext2_acl_header t_ext2_acl_header;
+ struct ext2_acl_entry t_ext2_acl_entry;
+ struct ext2_group_desc t_ext2_group_desc;
+ struct ext2_inode t_ext2_inode;
+ struct ext2_super_block t_ext2_super_block;
+ struct ext2_dir_entry t_ext2_dir_entry;
+ } u;
+};
+
+struct struct_file_system_info { /* Important information about the filesystem */
+ unsigned long long file_system_size;
+ unsigned long super_block_offset;
+ unsigned long first_group_desc_offset;
+ unsigned long groups_count;
+ unsigned long inodes_per_block;
+ unsigned long blocks_per_group; /* The name is misleading; beware */
+ unsigned long no_blocks_in_group;
+ unsigned short block_size;
+ struct ext2_super_block super_block;
+};
+
+struct struct_file_info { /* Used to handle files and directories */
+
+ struct ext2_inode *inode_ptr;
+
+ long inode_offset;
+ long global_block_num,global_block_offset;
+ long block_num,blocks_count;
+ long file_offset,file_length;
+ long level;
+ unsigned char buffer [EXT2_MAX_BLOCK_SIZE];
+ long offset_in_block;
+
+ int display;
+ /* The following is used if the file is a directory */
+
+ long dir_entry_num,dir_entries_count;
+ long dir_entry_offset;
+};
+
+struct struct_super_info { /* Used to handle the superblock */
+ unsigned long copy_num;
+};
+
+struct struct_group_info { /* Used to handle the group descriptors */
+ unsigned long copy_num;
+ unsigned long group_num;
+};
+
+struct struct_block_bitmap_info { /* Used in blockbitmap_com.c */
+ unsigned long entry_num;
+ unsigned long group_num;
+};
+
+struct struct_inode_bitmap_info { /* Used in inodebitmap_com.c */
+ unsigned long entry_num;
+ unsigned long group_num;
+};
+
+struct struct_remember_lifo { /* Implements the objects circular memory */
+ long entries_count;
+
+ long offset [REMEMBER_COUNT];
+ struct struct_descriptor *type [REMEMBER_COUNT];
+ char name [REMEMBER_COUNT][80];
+};
+
+struct struct_pad_info { /* Used to zoom into the pad window */
+ int display_lines,display_cols;
+ int line,col;
+ int max_line,max_col;
+ int disable_output;
+};
+
+/* Global variables (defined mostly in main.c) */
+
+/* Configurable variables (Through configuration file) */
+
+extern char AlternateDescriptors [200];
+extern char Ext2Descriptors [200];
+extern char LogFile [200];
+extern int LogChanges;
+extern int AllowChanges;
+extern int AllowMountedRead;
+extern int ForceExt2;
+extern int DefaultBlockSize;
+extern unsigned long DefaultTotalBlocks;
+extern unsigned long DefaultBlocksInGroup;
+extern int ForceDefault;
+
+extern char device_name [80];
+extern char last_command_line [80];
+extern FILE *device_handle;
+extern long device_offset;
+extern int mounted;
+
+extern short block_size;
+extern struct struct_commands general_commands;
+extern struct struct_commands ext2_commands;
+extern struct struct_descriptor *first_type;
+extern struct struct_descriptor *last_type;
+extern struct struct_descriptor *current_type;
+extern struct struct_type_data type_data;
+extern struct struct_file_system_info file_system_info;
+extern struct struct_file_info file_info,first_file_info;
+extern struct struct_group_info group_info;
+extern struct struct_super_info super_info;
+extern struct struct_block_bitmap_info block_bitmap_info;
+extern struct struct_inode_bitmap_info inode_bitmap_info;
+extern struct struct_remember_lifo remember_lifo;
+extern struct struct_pad_info show_pad_info;
+extern int write_access;
+
+extern int redraw_request;
+extern char lines_s [80];
+extern char cols_s [80];
+
+
+/* init.c */
+
+extern int init (void);
+extern void prepare_to_close (void);
+extern int set_struct_descriptors (char *file_name);
+extern void free_struct_descriptors (void);
+extern struct struct_descriptor *add_new_descriptor (char *name);
+extern void add_new_variable (struct struct_descriptor *descriptor,char *v_type,char *v_name);
+extern void fill_type_commands (struct struct_descriptor *ptr);
+extern void add_user_command (struct struct_commands *ptr,char *name,char *description,PF callback);
+extern void free_user_commands (struct struct_commands *ptr);
+extern int set_file_system_info (void);
+extern int process_configuration_file (void);
+extern void add_general_commands (void);
+extern void add_ext2_general_commands (void);
+extern void check_mounted (char *name);
+
+int get_next_option (FILE *fp,char *option,char *value);
+void init_readline (void);
+void init_signals (void);
+void signal_SIGWINCH_handler (int sig_num);
+void signal_SIGTERM_handler (int sig_num);
+void signal_SIGSEGV_handler (int sig_num);
+
+/* general_com.c */
+
+/* General commands which are aviable always */
+
+extern void help (char *command_line);
+extern void set (char *command_line);
+extern void set_device (char *command_line);
+extern void set_offset (char *command_line);
+extern void set_type (char *command_line);
+extern void show (char *command_line);
+extern void pgup (char *command_line);
+extern void pgdn (char *command_line);
+extern void redraw (char *command_line);
+extern void remember (char *command_line);
+extern void recall (char *command_line);
+extern void cd (char *command_line);
+extern void enable_write (char *command_line);
+extern void disable_write (char *command_line);
+extern void write_data (char *command_line);
+extern void next (char *command_line);
+extern void prev (char *command_line);
+
+void hex_set (char *command_line);
+void detailed_help (char *text);
+
+
+/* ext2_com.c */
+
+/* Extended2 filesystem genereal commands - Aviable only when editing an
+ ext2 filesystem */
+
+extern void type_ext2___super (char *command_line);
+extern void type_ext2___group (char *command_line);
+extern void type_ext2___cd (char *command_line);
+
+
+/* main.c */
+
+extern int version_major,version_minor;
+extern char revision_date [80];
+extern char email_address [80];
+
+#ifdef DEBUG
+extern void internal_error (char *description,char *source_name,char *function_name);
+#endif
+
+void parser (void);
+extern int dispatch (char *command_line);
+char *parse_word (char *source,char *dest);
+char *complete_command (char *text,int state);
+char *dupstr (char *src);
+
+
+
+/* disk.c */
+
+extern int load_type_data (void);
+extern int write_type_data (void);
+extern int low_read (unsigned char *buffer,unsigned long length,unsigned long offset);
+extern int low_write (unsigned char *buffer,unsigned long length,unsigned long offset);
+extern int log_changes (unsigned char *buffer,unsigned long length,unsigned long offset);
+
+/* file_com.c */
+
+extern int init_file_info (void);
+extern void type_file___show (char *command_line);
+extern void type_file___inode (char *command_line);
+extern void type_file___display (char *command_line);
+extern void type_file___prev (char *command_line);
+extern void type_file___next (char *command_line);
+extern void type_file___offset (char *command_line);
+extern void type_file___prevblock (char *command_line);
+extern void type_file___nextblock (char *command_line);
+extern void type_file___block (char *command_line);
+extern void type_file___remember (char *command_line);
+extern void type_file___set (char *command_line);
+extern void type_file___writedata (char *command_line);
+
+extern long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr);
+extern long return_indirect (long table_block,long block_num);
+extern long return_dindirect (long table_block,long block_num);
+extern long return_tindirect (long table_block,long block_num);
+
+void file_show_hex (void);
+void file_show_text (void);
+void show_status (void);
+
+/* inode_com.c */
+
+extern void type_ext2_inode___next (char *command_line);
+extern void type_ext2_inode___prev (char *command_line);
+extern void type_ext2_inode___show (char *command_line);
+extern void type_ext2_inode___group (char *command_line);
+extern void type_ext2_inode___entry (char *command_line);
+extern void type_ext2_inode___file (char *command_line);
+extern void type_ext2_inode___dir (char *command_line);
+
+extern long inode_offset_to_group_num (long inode_offset);
+extern long int inode_offset_to_inode_num (long inode_offset);
+extern long int inode_num_to_inode_offset (long inode_num);
+
+/* dir_com.c */
+
+extern int init_dir_info (struct struct_file_info *info);
+extern void type_dir___show (char *command_line);
+extern void type_dir___inode (char *command_line);
+extern void type_dir___pgdn (char *command_line);
+extern void type_dir___pgup (char *command_line);
+extern void type_dir___prev (char *command_line);
+extern void type_dir___next (char *command_line);
+extern void type_dir___followinode (char *command_line);
+extern void type_dir___remember (char *command_line);
+extern void type_dir___cd (char *command_line);
+extern void type_dir___entry (char *command_line);
+extern void type_dir___writedata (char *command_line);
+extern void type_dir___set (char *command_line);
+
+#define HEX 1
+#define TEXT 2
+
+#define ABORT 0
+#define CONTINUE 1
+#define FOUND 2
+
+struct struct_file_info search_dir_entries (int (*action) (struct struct_file_info *info),int *status);
+int action_count (struct struct_file_info *info);
+void show_dir_status (void);
+long count_dir_entries (void);
+int action_name (struct struct_file_info *info);
+int action_entry_num (struct struct_file_info *info);
+int action_show (struct struct_file_info *info);
+
+/* super_com.c */
+
+extern void type_ext2_super_block___show (char *command_line);
+extern void type_ext2_super_block___gocopy (char *command_line);
+extern void type_ext2_super_block___setactivecopy (char *command_line);
+
+/* group_com.c */
+
+extern void type_ext2_group_desc___next (char *command_line);
+extern void type_ext2_group_desc___prev (char *command_line);
+extern void type_ext2_group_desc___entry (char *command_line);
+extern void type_ext2_group_desc___show (char *command_line);
+extern void type_ext2_group_desc___inode (char *command_line);
+extern void type_ext2_group_desc___gocopy (char *command_line);
+extern void type_ext2_group_desc___blockbitmap (char *command_line);
+extern void type_ext2_group_desc___inodebitmap (char *command_line);
+extern void type_ext2_group_desc___setactivecopy (char *command_line);
+
+/* blockbitmap_com.c */
+
+extern void type_ext2_block_bitmap___show (char *command_line);
+extern void type_ext2_block_bitmap___entry (char *command_line);
+extern void type_ext2_block_bitmap___next (char *command_line);
+extern void type_ext2_block_bitmap___prev (char *command_line);
+extern void type_ext2_block_bitmap___allocate (char *command_line);
+extern void type_ext2_block_bitmap___deallocate (char *command_line);
+void allocate_block (long entry_num);
+void deallocate_block (long entry_num);
+
+/* inodebitmap_bom.c */
+
+extern void type_ext2_inode_bitmap___show (char *command_line);
+extern void type_ext2_inode_bitmap___entry (char *command_line);
+extern void type_ext2_inode_bitmap___next (char *command_line);
+extern void type_ext2_inode_bitmap___prev (char *command_line);
+extern void type_ext2_inode_bitmap___allocate (char *command_line);
+extern void type_ext2_inode_bitmap___deallocate (char *command_line);
+void allocate_inode (long entry_num);
+void deallocate_inode (long entry_num);
+
+/* win.c */
+
+extern WINDOW *title_win,*show_win,*command_win,*show_pad;
+
+extern void init_windows (void);
+extern void refresh_title_win (void);
+extern void refresh_show_win (void);
+extern void refresh_show_pad (void);
+extern void refresh_command_win (void);
+extern void show_info (void);
+extern void redraw_all (void);
+extern void close_windows (void);
+
+#endif /* EXT2ED_EDITOR_H */ \ No newline at end of file
diff --git a/ext2ed/file_com.c b/ext2ed/file_com.c
new file mode 100644
index 00000000..898df657
--- /dev/null
+++ b/ext2ed/file_com.c
@@ -0,0 +1,564 @@
+/*
+
+/usr/src/ext2ed/file_com.c
+
+A part of the extended file system 2 disk editor.
+
+----------------------------
+Commands which handle a file
+----------------------------
+
+First written on: April 18 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+int init_file_info (void)
+
+{
+ struct ext2_inode *ptr;
+
+ ptr=&type_data.u.t_ext2_inode;
+
+ file_info.inode_ptr=ptr;
+ file_info.inode_offset=device_offset;
+
+ file_info.global_block_num=ptr->i_block [0];
+ file_info.global_block_offset=ptr->i_block [0]*file_system_info.block_size;
+ file_info.block_num=0;
+ file_info.blocks_count=(ptr->i_size+file_system_info.block_size-1)/file_system_info.block_size;
+ file_info.file_offset=0;
+ file_info.file_length=ptr->i_size;
+ file_info.level=0;
+ file_info.offset_in_block=0;
+
+ file_info.display=HEX;
+
+ low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset);
+
+ return (1);
+}
+
+
+void type_file___inode (char *command_line)
+
+{
+ dispatch ("settype ext2_inode");
+}
+
+void type_file___show (char *command_line)
+
+{
+ if (file_info.display==HEX)
+ file_show_hex ();
+ if (file_info.display==TEXT)
+ file_show_text ();
+}
+
+void type_file___nextblock (char *command_line)
+
+{
+ long block_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ block_offset*=atol (buffer);
+ }
+
+ if (file_info.block_num+block_offset >= file_info.blocks_count) {
+ wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win);
+ return;
+ }
+
+ file_info.block_num+=block_offset;
+ file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info);
+ file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size;
+ file_info.file_offset=file_info.block_num*file_system_info.block_size;
+
+ low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset);
+
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+void type_file___next (char *command_line)
+
+{
+ int offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ offset*=atol (buffer);
+ }
+
+ if (file_info.offset_in_block+offset < file_system_info.block_size) {
+ file_info.offset_in_block+=offset;
+ sprintf (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Offset out of block\n");refresh_command_win ();
+ }
+}
+
+void type_file___offset (char *command_line)
+
+{
+ unsigned long offset;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ offset=atol (buffer);
+ }
+ else {
+ wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();
+ return;
+ }
+
+ if (offset < file_system_info.block_size) {
+ file_info.offset_in_block=offset;
+ sprintf (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Offset out of block\n");refresh_command_win ();
+ }
+}
+
+void type_file___prev (char *command_line)
+
+{
+ int offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ offset*=atol (buffer);
+ }
+
+ if (file_info.offset_in_block-offset >= 0) {
+ file_info.offset_in_block-=offset;
+ sprintf (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Offset out of block\n");refresh_command_win ();
+ }
+}
+
+void type_file___prevblock (char *command_line)
+
+{
+ long block_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ block_offset*=atol (buffer);
+ }
+
+ if (file_info.block_num-block_offset < 0) {
+ wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win);
+ return;
+ }
+
+ file_info.block_num-=block_offset;
+ file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info);
+ file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size;
+ file_info.file_offset=file_info.block_num*file_system_info.block_size;
+
+ low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset);
+
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+void type_file___block (char *command_line)
+
+{
+ long block_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Invalid arguments\n");wrefresh (command_win);
+ return;
+ }
+
+ ptr=parse_word (ptr,buffer);
+ block_offset=atol (buffer);
+
+ if (block_offset < 0 || block_offset >= file_info.blocks_count) {
+ wprintw (command_win,"Error - Block offset out of range\n");wrefresh (command_win);
+ return;
+ }
+
+ file_info.block_num=block_offset;
+ file_info.global_block_num=file_block_to_global_block (file_info.block_num,&file_info);
+ file_info.global_block_offset=file_info.global_block_num*file_system_info.block_size;
+ file_info.file_offset=file_info.block_num*file_system_info.block_size;
+
+ low_read (file_info.buffer,file_system_info.block_size,file_info.global_block_offset);
+
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+void type_file___display (char *command_line)
+
+{
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0)
+ strcpy (buffer,"hex");
+ else
+ ptr=parse_word (ptr,buffer);
+
+ if (strcasecmp (buffer,"hex")==0) {
+ wprintw (command_win,"Display set to hex\n");wrefresh (command_win);
+ file_info.display=HEX;
+ sprintf (buffer,"show");dispatch (buffer);
+ }
+
+ else if (strcasecmp (buffer,"text")==0) {
+ wprintw (command_win,"Display set to text\n");wrefresh (command_win);
+ file_info.display=TEXT;
+ sprintf (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Invalid arguments\n");wrefresh (command_win);
+ }
+}
+
+void file_show_hex (void)
+
+{
+ long offset=0,l,i;
+ unsigned char *ch_ptr;
+
+ /* device_offset and type_data points to the inode */
+
+ show_pad_info.line=0;
+
+ wmove (show_pad,0,0);
+ ch_ptr=file_info.buffer;
+ for (l=0;l<file_system_info.block_size/16;l++) {
+ if (file_info.file_offset+offset>file_info.file_length-1) break;
+ wprintw (show_pad,"%08ld : ",offset);
+ for (i=0;i<16;i++) {
+
+ if (file_info.file_offset+offset+i>file_info.file_length-1) {
+ wprintw (show_pad," ");
+ }
+
+ else {
+ if (file_info.offset_in_block==offset+i)
+ wattrset (show_pad,A_REVERSE);
+
+ if (ch_ptr [i]>=' ' && ch_ptr [i]<='z')
+ wprintw (show_pad,"%c",ch_ptr [i]);
+ else
+ wprintw (show_pad,".");
+
+ if (file_info.offset_in_block==offset+i)
+ wattrset (show_pad,A_NORMAL);
+ }
+ }
+
+ wprintw (show_pad," ");
+ for (i=0;i<16;i++) {
+ if (file_info.file_offset+offset+i>file_info.file_length-1) break;
+ if (file_info.offset_in_block==offset+i)
+ wattrset (show_pad,A_REVERSE);
+
+ wprintw (show_pad,"%02x",ch_ptr [i]);
+
+ if (file_info.offset_in_block==offset+i) {
+ wattrset (show_pad,A_NORMAL);
+ show_pad_info.line=l-l % show_pad_info.display_lines;
+ }
+
+ wprintw (show_pad," ");
+
+ }
+
+ wprintw (show_pad,"\n");
+ offset+=i;
+ ch_ptr+=i;
+ }
+
+ show_pad_info.max_line=l-1;
+
+ refresh_show_pad ();
+
+ show_status ();
+}
+
+void file_show_text (void)
+
+{
+ long offset=0,last_offset,l=0,cols=0;
+ unsigned char *ch_ptr;
+
+ /* device_offset and type_data points to the inode */
+
+ show_pad_info.line=0;
+ wmove (show_pad,0,0);
+ ch_ptr=file_info.buffer;
+
+ last_offset=file_system_info.block_size-1;
+
+ if (file_info.file_offset+last_offset > file_info.file_length-1)
+ last_offset=file_info.file_length-1-file_info.file_offset;
+
+ while ( (offset <= last_offset) && l<SHOW_PAD_LINES) {
+
+ if (cols==SHOW_PAD_COLS-1) {
+ wprintw (show_pad,"\n");
+ l++;cols=0;
+ }
+
+
+ if (file_info.offset_in_block==offset)
+ wattrset (show_pad,A_REVERSE);
+
+ if (*ch_ptr >= ' ' && *ch_ptr <= 'z')
+ wprintw (show_pad,"%c",*ch_ptr);
+
+
+ else {
+ if (*ch_ptr == 0xa) {
+ wprintw (show_pad,"\n");
+ l++;cols=0;
+ }
+
+ else if (*ch_ptr == 0x9)
+ wprintw (show_pad," ");
+
+ else
+ wprintw (show_pad,".");
+ }
+
+ if (file_info.offset_in_block==offset) {
+ wattrset (show_pad,A_NORMAL);
+ show_pad_info.line=l-l % show_pad_info.display_lines;
+ }
+
+
+ offset++;cols++;ch_ptr++;
+ }
+
+ wprintw (show_pad,"\n");
+ show_pad_info.max_line=l;
+
+ refresh_show_pad ();
+
+ show_status ();
+}
+
+void show_status (void)
+
+{
+ long inode_num;
+
+ werase (show_win);wmove (show_win,0,0);
+ wprintw (show_win,"File contents. Block %ld. ",file_info.global_block_num);
+ wprintw (show_win,"File block %ld of %ld. ",file_info.block_num,file_info.blocks_count-1);
+ wprintw (show_win,"File Offset %ld of %ld.",file_info.file_offset,file_info.file_length-1);
+
+ wmove (show_win,1,0);
+ inode_num=inode_offset_to_inode_num (file_info.inode_offset);
+ wprintw (show_win,"File inode %ld. Indirection level %ld.",inode_num,file_info.level);
+
+ refresh_show_win ();
+}
+
+void type_file___remember (char *command_line)
+
+{
+ int found=0;
+ long entry_num;
+ char *ptr,buffer [80];
+ struct struct_descriptor *descriptor_ptr;
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Argument not specified\n");wrefresh (command_win);
+ return;
+ }
+
+ ptr=parse_word (ptr,buffer);
+
+ entry_num=remember_lifo.entries_count++;
+ if (entry_num>REMEMBER_COUNT-1) {
+ entry_num=0;
+ remember_lifo.entries_count--;
+ }
+
+ descriptor_ptr=first_type;
+ while (descriptor_ptr!=NULL && !found) {
+ if (strcmp (descriptor_ptr->name,"ext2_inode")==0)
+ found=1;
+ else
+ descriptor_ptr=descriptor_ptr->next;
+ }
+
+
+ remember_lifo.offset [entry_num]=device_offset;
+ remember_lifo.type [entry_num]=descriptor_ptr;
+ strcpy (remember_lifo.name [entry_num],buffer);
+
+ wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",descriptor_ptr->name,device_offset,buffer);
+ wrefresh (command_win);
+}
+
+void type_file___set (char *command_line)
+
+{
+ unsigned char tmp;
+ char *ptr,buffer [80],*ch_ptr;
+ int mode=HEX;
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();return;
+ }
+
+ ptr=parse_word (ptr,buffer);
+
+ if (strcasecmp (buffer,"text")==0) {
+ mode=TEXT;
+ strcpy (buffer,ptr);
+ }
+
+ else if (strcasecmp (buffer,"hex")==0) {
+ mode=HEX;
+ ptr=parse_word (ptr,buffer);
+ }
+
+ if (*buffer==0) {
+ wprintw (command_win,"Error - Data not specified\n");refresh_command_win ();return;
+ }
+
+ if (mode==HEX) {
+ do {
+ tmp=(unsigned char) strtol (buffer,NULL,16);
+ file_info.buffer [file_info.offset_in_block]=tmp;
+ file_info.offset_in_block++;
+ ptr=parse_word (ptr,buffer);
+ if (file_info.offset_in_block==file_system_info.block_size) {
+ if (*ptr) {
+ wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n");
+ refresh_command_win ();
+ }
+ file_info.offset_in_block--;
+ }
+ } while (*buffer) ;
+ }
+
+ else {
+ ch_ptr=buffer;
+ while (*ch_ptr) {
+ tmp=(unsigned char) *ch_ptr++;
+ file_info.buffer [file_info.offset_in_block]=tmp;
+ file_info.offset_in_block++;
+ if (file_info.offset_in_block==file_system_info.block_size) {
+ if (*ch_ptr) {
+ wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n");
+ refresh_command_win ();
+ }
+ file_info.offset_in_block--;
+ }
+ }
+ }
+
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+void type_file___writedata (char *command_line)
+
+{
+ low_write (file_info.buffer,file_system_info.block_size,file_info.global_block_offset);
+ return;
+}
+
+long file_block_to_global_block (long file_block,struct struct_file_info *file_info_ptr)
+
+{
+ long last_direct,last_indirect,last_dindirect;
+
+ last_direct=EXT2_NDIR_BLOCKS-1;
+ last_indirect=last_direct+file_system_info.block_size/4;
+ last_dindirect=last_indirect+(file_system_info.block_size/4)*(file_system_info.block_size/4);
+
+ if (file_block <= last_direct) {
+ file_info_ptr->level=0;
+ return (file_info_ptr->inode_ptr->i_block [file_block]);
+ }
+
+ if (file_block <= last_indirect) {
+ file_info_ptr->level=1;
+ file_block=file_block-last_direct-1;
+ return (return_indirect (file_info_ptr->inode_ptr->i_block [EXT2_IND_BLOCK],file_block));
+ }
+
+ if (file_block <= last_dindirect) {
+ file_info_ptr->level=2;
+ file_block=file_block-last_indirect-1;
+ return (return_dindirect (file_info_ptr->inode_ptr->i_block [EXT2_DIND_BLOCK],file_block));
+ }
+
+ file_info_ptr->level=3;
+ file_block=file_block-last_dindirect-1;
+ return (return_tindirect (file_info_ptr->inode_ptr->i_block [EXT2_TIND_BLOCK],file_block));
+}
+
+long return_indirect (long table_block,long block_num)
+
+{
+ long block_table [EXT2_MAX_BLOCK_SIZE/4];
+
+ low_read ((char *) block_table,file_system_info.block_size,table_block*file_system_info.block_size);
+ return (block_table [block_num]);
+}
+
+long return_dindirect (long table_block,long block_num)
+
+{
+ long f_indirect;
+
+ f_indirect=block_num/(file_system_info.block_size/4);
+ f_indirect=return_indirect (table_block,f_indirect);
+ return (return_indirect (f_indirect,block_num%(file_system_info.block_size/4)));
+}
+
+long return_tindirect (long table_block,long block_num)
+
+{
+ long s_indirect;
+
+ s_indirect=block_num/((file_system_info.block_size/4)*(file_system_info.block_size/4));
+ s_indirect=return_indirect (table_block,s_indirect);
+ return (return_dindirect (s_indirect,block_num%((file_system_info.block_size/4)*(file_system_info.block_size/4))));
+}
diff --git a/ext2ed/general_com.c b/ext2ed/general_com.c
new file mode 100644
index 00000000..a8ebdc3a
--- /dev/null
+++ b/ext2ed/general_com.c
@@ -0,0 +1,748 @@
+/*
+
+/usr/src/ext2ed/general_com.c
+
+A part of the extended file system 2 disk editor.
+
+---------------------
+General user commands
+---------------------
+
+First written on: April 9 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+void help (char *command_line)
+
+{
+ int i,max_line=0;
+ char argument [80],*ptr;
+
+ werase (show_pad);wmove (show_pad,0,0);
+
+ ptr=parse_word (command_line,argument);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,argument);
+ if (*argument!=0) {
+ detailed_help (argument);
+ return;
+ }
+ }
+
+ if (current_type!=NULL) {
+
+ wprintw (show_pad,"Type %s specific commands:\n",current_type->name);max_line++;
+
+ if (current_type->type_commands.last_command==-1) {
+ wprintw (show_pad,"\nnone\n");max_line+=2;
+ }
+ else
+ for (i=0;i<=current_type->type_commands.last_command;i++) {
+ if (i%5==0) {
+ wprintw (show_pad,"\n");max_line++;
+ }
+ wprintw (show_pad,"%-13s",current_type->type_commands.names [i]);
+ if (i%5!=4)
+ wprintw (show_pad,"; ");
+ }
+
+ wprintw (show_pad,"\n\n");max_line+=2;
+ }
+
+ if (ext2_commands.last_command != -1) {
+ wprintw (show_pad,"ext2 filesystem general commands: \n");max_line++;
+ for (i=0;i<=ext2_commands.last_command;i++) {
+ if (i%5==0) {
+ wprintw (show_pad,"\n");max_line++;
+ }
+ wprintw (show_pad,"%-13s",ext2_commands.names [i]);
+ if (i%5!=4)
+ wprintw (show_pad,"; ");
+
+ }
+ wprintw (show_pad,"\n\n");max_line+=2;
+ }
+
+ wprintw (show_pad,"General commands: \n");
+
+ for (i=0;i<=general_commands.last_command;i++) {
+ if (i%5==0) {
+ wprintw (show_pad,"\n");max_line++;
+ }
+ wprintw (show_pad,"%-13s",general_commands.names [i]);
+ if (i%5!=4)
+ wprintw (show_pad,"; ");
+ }
+
+ wprintw (show_pad,"\n\n");max_line+=2;
+
+ wprintw (show_pad,"EXT2ED ver %d.%d (%s)\n",version_major,version_minor,revision_date);
+ wprintw (show_pad,"Copyright (C) 1995 Gadi Oxman\n");
+ wprintw (show_pad,"EXT2ED is hereby placed under the terms of the GNU General Public License.\n\n");
+ wprintw (show_pad,"EXT2ED was programmed as a student project in the software laboratory\n");
+ wprintw (show_pad,"of the faculty of electrical engineering in the\n");
+ wprintw (show_pad,"Technion - Israel Institute of Technology\n");
+ wprintw (show_pad,"with the guide of Avner Lottem and Dr. Ilana David.\n");
+
+ max_line+=6;
+
+ wprintw (show_pad,"\n\n");max_line+=2;
+
+ wprintw (show_pad,"Please feel free to mail me at (currently) %s\n",email_address);
+ wprintw (show_pad,"with any commet, suggestion, and of-course, bug report concerning EXT2ED.\n");
+
+ max_line+=2;
+
+ show_pad_info.line=0;show_pad_info.max_line=max_line;
+
+ werase (show_win);wmove (show_win,0,0);
+ wprintw (show_win,"EXT2ED help");
+
+ refresh_show_win ();
+ refresh_show_pad ();
+}
+
+void detailed_help (char *text)
+
+{
+ int i;
+
+ if (current_type != NULL)
+ for (i=0;i<=current_type->type_commands.last_command;i++) {
+ if (strcmp (current_type->type_commands.names [i],text)==0) {
+ wprintw (show_pad,"%s - %s\n",text,current_type->type_commands.descriptions [i]);
+ refresh_show_pad ();return;
+ }
+ }
+
+ for (i=0;i<=ext2_commands.last_command;i++) {
+ if (strcmp (ext2_commands.names [i],text)==0) {
+ wprintw (show_pad,"%s - %s\n",text,ext2_commands.descriptions [i]);
+ refresh_show_pad ();return;
+ }
+ }
+
+ for (i=0;i<=general_commands.last_command;i++) {
+ if (strcmp (general_commands.names [i],text)==0) {
+ wprintw (show_pad,"%s - %s\n",text,general_commands.descriptions [i]);
+ refresh_show_pad ();return;
+ }
+ }
+
+ if (strcmp ("quit",text)==0) {
+ wprintw (show_pad,"quit - Exists EXT2ED");
+ refresh_show_pad ();return;
+ }
+
+ wprintw (show_pad,"Error - Command %s not aviable now\n",text);
+ refresh_show_pad ();return;
+}
+
+
+
+void set_device (char *command_line)
+
+{
+ char *ptr,new_device [80];
+
+ ptr=parse_word (command_line,new_device);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Device name not specified\n");
+ refresh_command_win ();return;
+ }
+ parse_word (ptr,new_device);
+ check_mounted (new_device);
+ if (mounted && !AllowMountedRead) {
+ wprintw (command_win,"Error - Filesystem is mounted, aborting\n");
+ wprintw (command_win,"You may wish to use the AllowMountedRead on configuration option\n");
+ refresh_command_win ();return;
+ }
+
+ if (mounted && AllowMountedRead) {
+ wprintw (command_win,"Warning - Filesystem is mounted. Displayed data may be unreliable.\n");
+ refresh_command_win ();
+ }
+
+ if (device_handle!=NULL)
+ fclose (device_handle);
+
+ if ( (device_handle=fopen (new_device,"rb"))==NULL) {
+ wprintw (command_win,"Error - Can not open device %s\n",new_device);refresh_command_win ();
+ return;
+ }
+ else {
+ strcpy (device_name,new_device);
+ write_access=0; /* Write access disabled */
+ current_type=NULL; /* There is no type now */
+ remember_lifo.entries_count=0; /* Empty Object memory */
+ free_user_commands (&ext2_commands); /* Free filesystem specific objects */
+ free_struct_descriptors ();
+ if (!set_file_system_info ()) { /* Error while getting info --> abort */
+ free_user_commands (&ext2_commands);
+ free_struct_descriptors ();
+ fclose (device_handle);
+ device_handle=NULL; /* Notice that our device is still not set up */
+ device_offset=-1;
+ return;
+ }
+ if (*AlternateDescriptors) /* Check if user defined objects exist */
+ set_struct_descriptors (AlternateDescriptors);
+ dispatch ("setoffset 0");
+ dispatch ("help"); /* Show help screen */
+ wprintw (command_win,"Device changed to %s",device_name);refresh_command_win ();
+ }
+}
+
+void set_offset (char *command_line)
+
+{
+ long mult=1;
+ long new_offset;
+ char *ptr,new_offset_buffer [80];
+
+ if (device_handle==NULL) {
+ wprintw (command_win,"Error - No device opened\n");refresh_command_win ();
+ return;
+ }
+
+ ptr=parse_word (command_line,new_offset_buffer);
+
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();
+ return;
+ }
+
+ ptr=parse_word (ptr,new_offset_buffer);
+
+ if (strcmp (new_offset_buffer,"block")==0) {
+ mult=file_system_info.block_size;
+ ptr=parse_word (ptr,new_offset_buffer);
+ }
+
+ if (strcmp (new_offset_buffer,"type")==0) {
+ if (current_type==NULL) {
+ wprintw (command_win,"Error - No type set\n");refresh_command_win ();
+ return;
+ }
+
+ mult=current_type->length;
+ ptr=parse_word (ptr,new_offset_buffer);
+ }
+
+ if (*new_offset_buffer==0) {
+ wprintw (command_win,"Error - No offset specified\n");refresh_command_win ();
+ return;
+ }
+
+ if (new_offset_buffer [0]=='+') {
+ if (device_offset==-1) {
+ wprintw (command_win,"Error - Select a fixed offset first\n");refresh_command_win ();
+ return;
+ }
+ new_offset=device_offset+atol (new_offset_buffer+1)*mult;
+ }
+
+ else if (new_offset_buffer [0]=='-') {
+ if (device_offset==-1) {
+ wprintw (command_win,"Error - Select a fixed offset first\n");refresh_command_win ();
+ return;
+ }
+ new_offset=device_offset-atol (new_offset_buffer+1)*mult;
+ if (new_offset<0) new_offset=0;
+ }
+
+ else
+ new_offset=atol (new_offset_buffer)*mult;
+
+ if ( (fseek (device_handle,new_offset,SEEK_SET))==-1) {
+ wprintw (command_win,"Error - Failed to seek to offset %ld in device %s\n",new_offset,device_name);
+ refresh_command_win ();
+ return;
+ };
+ device_offset=new_offset;
+ wprintw (command_win,"Device offset changed to %ld\n",device_offset);refresh_command_win ();
+ load_type_data ();
+ type_data.offset_in_block=0;
+}
+
+void set (char *command_line)
+
+{
+ unsigned short *int_ptr;
+ unsigned char *char_ptr;
+ unsigned long *long_ptr,offset=0;
+ int i,found=0;
+ char *ptr,buffer [80],variable [80],value [80];
+
+ if (device_handle==NULL) {
+ wprintw (command_win,"Error - No device opened\n");refresh_command_win ();
+ return;
+ }
+
+ if (current_type==NULL) {
+ hex_set (command_line);
+ return;
+ }
+
+ ptr=parse_word (command_line,buffer);
+ if (ptr==NULL || *ptr==0) {
+ wprintw (command_win,"Error - Missing arguments\n");refresh_command_win ();
+ return;
+ }
+ parse_word (ptr,buffer);
+ ptr=strchr (buffer,'=');
+ if (ptr==NULL) {
+ wprintw (command_win,"Error - Bad syntax\n");refresh_command_win ();return;
+ }
+ strncpy (variable,buffer,ptr-buffer);variable [ptr-buffer]=0;
+ strcpy (value,++ptr);
+
+ if (current_type==NULL) {
+ wprintw (command_win,"Sorry, not yet supported\n");refresh_command_win ();return;
+ }
+
+ for (i=0;i<current_type->fields_num && !found;i++) {
+ if (strcmp (current_type->field_names [i],variable)==0) {
+ found=1;
+ ptr=type_data.u.buffer+offset;
+ switch (current_type->field_lengths [i]) {
+ case 1:
+ char_ptr=(unsigned char *) ptr;
+ *char_ptr=(char) atoi (value);
+ wprintw (command_win,"Variable %s set to %u\n",variable,*char_ptr);refresh_command_win ();
+ break;
+ case 2:
+ int_ptr=(unsigned short *) ptr;
+ *int_ptr=atoi (value);
+ wprintw (command_win,"Variable %s set to %u\n",variable,*int_ptr);refresh_command_win ();
+ break;
+
+ case 4:
+ long_ptr=(unsigned long *) ptr;
+ *long_ptr=atol (value);
+ wprintw (command_win,"Variable %s set to %lu\n",variable,*long_ptr);refresh_command_win ();
+ break;
+ }
+ }
+ offset+=current_type->field_lengths [i];
+ }
+ if (found)
+ dispatch ("show");
+ else {
+ wprintw (command_win,"Error - Variable %s not found\n",variable);
+ refresh_command_win ();
+ }
+}
+
+void hex_set (char *command_line)
+
+{
+ unsigned char tmp;
+ char *ptr,buffer [80],*ch_ptr;
+ int mode=HEX;
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();return;
+ }
+
+ ptr=parse_word (ptr,buffer);
+
+ if (strcasecmp (buffer,"text")==0) {
+ mode=TEXT;
+ strcpy (buffer,ptr);
+ }
+
+ else if (strcasecmp (buffer,"hex")==0) {
+ mode=HEX;
+ ptr=parse_word (ptr,buffer);
+ }
+
+ if (*buffer==0) {
+ wprintw (command_win,"Error - Data not specified\n");refresh_command_win ();return;
+ }
+
+ if (mode==HEX) {
+ do {
+ tmp=(unsigned char) strtol (buffer,NULL,16);
+ type_data.u.buffer [type_data.offset_in_block]=tmp;
+ type_data.offset_in_block++;
+ ptr=parse_word (ptr,buffer);
+ if (type_data.offset_in_block==file_system_info.block_size) {
+ if (*ptr) {
+ wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n");
+ refresh_command_win ();
+ }
+ type_data.offset_in_block--;
+ }
+ } while (*buffer) ;
+ }
+
+ else {
+ ch_ptr=buffer;
+ while (*ch_ptr) {
+ tmp=(unsigned char) *ch_ptr++;
+ type_data.u.buffer [type_data.offset_in_block]=tmp;
+ type_data.offset_in_block++;
+ if (type_data.offset_in_block==file_system_info.block_size) {
+ if (*ch_ptr) {
+ wprintw (command_win,"Error - Ending offset outside block, only partial string changed\n");
+ refresh_command_win ();
+ }
+ type_data.offset_in_block--;
+ }
+ }
+ }
+
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+
+
+void set_type (char *command_line)
+
+{
+ struct struct_descriptor *descriptor_ptr;
+ char *ptr,buffer [80],tmp_buffer [80];
+ short found=0;
+
+ if (!load_type_data ())
+ return;
+
+ ptr=parse_word (command_line,buffer);
+ parse_word (ptr,buffer);
+
+ if (strcmp (buffer,"none")==0 || strcmp (buffer,"hex")==0) {
+ wprintw (command_win,"Data will be shown as hex dump\n");refresh_command_win ();
+ current_type=NULL;
+ sprintf (tmp_buffer,"show");dispatch (tmp_buffer);
+ return;
+ }
+
+ descriptor_ptr=first_type;
+ while (descriptor_ptr!=NULL && !found) {
+ if (strcmp (descriptor_ptr->name,buffer)==0)
+ found=1;
+ else
+ descriptor_ptr=descriptor_ptr->next;
+ }
+ if (found) {
+ wprintw (command_win,"Structure type set to %s\n",buffer);refresh_command_win ();
+ current_type=descriptor_ptr;
+ sprintf (tmp_buffer,"show");dispatch (tmp_buffer);
+ }
+ else {
+ wprintw (command_win,"Error - %s is not a valid type\n",buffer);refresh_command_win ();
+ }
+}
+
+
+void show (char *command_line)
+
+{
+ unsigned int i,l,temp_int;
+ unsigned long offset=0,temp_long;
+ unsigned char temp_char,*ch_ptr;
+ void *ptr;
+
+ if (device_handle==NULL)
+ return;
+
+ show_pad_info.line=0;
+
+ if (current_type==NULL) {
+ wmove (show_pad,0,0);
+ ch_ptr=type_data.u.buffer;
+ for (l=0;l<file_system_info.block_size/16;l++) {
+ wprintw (show_pad,"%08ld : ",offset);
+ for (i=0;i<16;i++) {
+ if (type_data.offset_in_block==offset+i)
+ wattrset (show_pad,A_REVERSE);
+
+ if (ch_ptr [i]>=' ' && ch_ptr [i]<='z')
+ wprintw (show_pad,"%c",ch_ptr [i]);
+ else
+ wprintw (show_pad,".");
+ if (type_data.offset_in_block==offset+i)
+ wattrset (show_pad,A_NORMAL);
+ }
+ wprintw (show_pad," ");
+ for (i=0;i<16;i++) {
+ if (type_data.offset_in_block==offset+i)
+ wattrset (show_pad,A_REVERSE);
+
+ wprintw (show_pad,"%02x",ch_ptr [i]);
+
+ if (type_data.offset_in_block==offset+i) {
+ wattrset (show_pad,A_NORMAL);
+ show_pad_info.line=l-l % show_pad_info.display_lines;
+ }
+
+ wprintw (show_pad," ");
+ }
+ wprintw (show_pad,"\n");
+ offset+=16;
+ ch_ptr+=16;
+ }
+ show_pad_info.max_line=l-1;show_pad_info.max_col=COLS-1;
+ refresh_show_pad ();show_info ();
+ }
+ else {
+ wmove (show_pad,0,0);l=0;
+ for (i=0;i<current_type->fields_num;i++) {
+ wprintw (show_pad,"%-20s = ",current_type->field_names [i]);
+ ptr=type_data.u.buffer+offset;
+ switch (current_type->field_lengths [i]) {
+ case 1:
+ temp_char=*((unsigned char *) ptr);
+ wprintw (show_pad,"%3u (0x%02x",temp_char,temp_char);
+ if (temp_char>=' ' && temp_char<='z')
+ wprintw (show_pad," , %c)\n",temp_char);
+ else
+ wprintw (show_pad,")\n");
+
+ offset ++;l++;
+ break;
+ case 2:
+ temp_int=*((unsigned short *) ptr);
+ wprintw (show_pad,"%u (0x%x)\n",temp_int,temp_int);
+ offset +=2;l++;
+ break;
+ case 4:
+ temp_long=*((unsigned long *) ptr);
+ wprintw (show_pad,"%lu\n",temp_long);
+ offset +=4;l++;
+ break;
+ }
+/* offset+=current_type->field_lengths [i]; */
+ }
+ current_type->length=offset;
+ show_pad_info.max_line=l-1;
+ refresh_show_pad ();show_info ();
+ }
+}
+
+void next (char *command_line)
+
+{
+ long offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ offset*=atol (buffer);
+ }
+
+ if (current_type!=NULL) {
+ sprintf (buffer,"setoffset type +%ld",offset);
+ dispatch (buffer);
+ return;
+ }
+
+ if (type_data.offset_in_block+offset < file_system_info.block_size) {
+ type_data.offset_in_block+=offset;
+ sprintf (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Offset out of block\n");refresh_command_win ();
+ }
+}
+
+void prev (char *command_line)
+
+{
+ long offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ offset*=atol (buffer);
+ }
+
+ if (current_type!=NULL) {
+ sprintf (buffer,"setoffset type -%ld",offset);
+ dispatch (buffer);
+ return;
+ }
+
+ if (type_data.offset_in_block-offset >= 0) {
+ type_data.offset_in_block-=offset;
+ sprintf (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Offset out of block\n");refresh_command_win ();
+ }
+}
+
+void pgdn (char *commnad_line)
+
+{
+ show_pad_info.line+=show_pad_info.display_lines;
+ refresh_show_pad ();refresh_show_win ();
+}
+
+void pgup (char *command_line)
+
+{
+ show_pad_info.line-=show_pad_info.display_lines;
+ refresh_show_pad ();refresh_show_win ();
+}
+
+void redraw (char *command_line)
+
+{
+ redraw_all ();
+ dispatch ("show");
+}
+
+void remember (char *command_line)
+
+{
+ long entry_num;
+ char *ptr,buffer [80];
+
+ if (device_handle==NULL) {
+ wprintw (command_win,"Error - No device opened\n");refresh_command_win ();
+ return;
+ }
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();
+ return;
+ }
+
+ ptr=parse_word (ptr,buffer);
+
+ entry_num=remember_lifo.entries_count++;
+ if (entry_num>REMEMBER_COUNT-1) {
+ entry_num=0;
+ remember_lifo.entries_count--;
+ }
+
+ remember_lifo.offset [entry_num]=device_offset;
+ remember_lifo.type [entry_num]=current_type;
+ strcpy (remember_lifo.name [entry_num],buffer);
+
+ if (current_type!=NULL)
+ wprintw (command_win,"Object %s in Offset %ld remembered as %s\n",current_type->name,device_offset,buffer);
+ else
+ wprintw (command_win,"Offset %ld remembered as %s\n",device_offset,buffer);
+
+ refresh_command_win ();
+}
+
+void recall (char *command_line)
+
+{
+ char *ptr,buffer [80];
+ long entry_num;
+
+ if (device_handle==NULL) {
+ wprintw (command_win,"Error - No device opened\n");refresh_command_win ();
+ return;
+ }
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr==0) {
+ wprintw (command_win,"Error - Argument not specified\n");refresh_command_win ();
+ return;
+ }
+
+ ptr=parse_word (ptr,buffer);
+
+
+ for (entry_num=remember_lifo.entries_count-1;entry_num>=0;entry_num--) {
+ if (strcmp (remember_lifo.name [entry_num],buffer)==0)
+ break;
+ }
+
+ if (entry_num==-1) {
+ wprintw (command_win,"Error - Can not recall %s\n",buffer);refresh_command_win ();
+ return;
+ }
+
+ sprintf (buffer,"setoffset %ld",remember_lifo.offset [entry_num]);dispatch (buffer);
+ if (remember_lifo.type [entry_num] != NULL) {
+ sprintf (buffer,"settype %s",remember_lifo.type [entry_num]->name);dispatch (buffer);
+ }
+
+ else {
+ sprintf (buffer,"settype none");dispatch (buffer);
+ }
+
+ wprintw (command_win,"Object %s in Offset %ld recalled\n",current_type->name,device_offset);
+ refresh_command_win ();
+}
+
+void enable_write (char *command_line)
+
+{
+ FILE *fp;
+
+ if (device_handle==NULL) {
+ wprintw (command_win,"Error - No device opened\n");refresh_command_win ();
+ return;
+ }
+
+ if (!AllowChanges) {
+ wprintw (command_win,"Sorry, write access is not allowed\n");
+ return;
+ }
+
+ if (mounted) {
+ wprintw (command_win,"Error - Filesystem is mounted\n");
+ return;
+ }
+
+ if ( (fp=fopen (device_name,"r+b"))==NULL) {
+ wprintw (command_win,"Error - Can not open device %s for reading and writing\n",device_name);refresh_command_win ();
+ return;
+ }
+ fclose (device_handle);
+ device_handle=fp;write_access=1;
+ wprintw (command_win,"Write access enabled - Be careful\n");refresh_command_win ();
+}
+
+void disable_write (char *command_line)
+
+{
+ FILE *fp;
+
+ if (device_handle==NULL) {
+ wprintw (command_win,"Error - No device opened\n");refresh_command_win ();
+ return;
+ }
+
+ if ( (fp=fopen (device_name,"rb"))==NULL) {
+ wprintw (command_win,"Error - Can not open device %s\n",device_name);refresh_command_win ();
+ return;
+ }
+
+ fclose (device_handle);
+ device_handle=fp;write_access=0;
+ wprintw (command_win,"Write access disabled\n");refresh_command_win ();
+}
+
+void write_data (char *command_line)
+
+{
+ write_type_data ();
+}
diff --git a/ext2ed/group_com.c b/ext2ed/group_com.c
new file mode 100644
index 00000000..ee6aabc1
--- /dev/null
+++ b/ext2ed/group_com.c
@@ -0,0 +1,182 @@
+/*
+
+/usr/src/ext2ed/group_com.c
+
+A part of the extended file system 2 disk editor.
+
+General user commands
+
+First written on: April 17 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+void type_ext2_group_desc___next (char *command_line)
+
+{
+ long entry_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ entry_offset=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",group_info.group_num+entry_offset);
+ dispatch (buffer);
+}
+
+void type_ext2_group_desc___prev (char *command_line)
+
+{
+ long entry_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ entry_offset=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",group_info.group_num-entry_offset);
+ dispatch (buffer);
+}
+
+void type_ext2_group_desc___entry (char *command_line)
+
+{
+ long group_num;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return;
+ }
+ ptr=parse_word (ptr,buffer);
+
+ group_num=atol (buffer);
+
+ if (group_num < 0 || group_num >= file_system_info.groups_count) {
+ wprintw (command_win,"Error - Entry number out of bounds\n");refresh_command_win ();return;
+ }
+
+ device_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+
+ sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer);
+ strcpy (buffer,"show");dispatch (buffer);
+ group_info.group_num=group_num;
+}
+
+
+void type_ext2_group_desc___gocopy (char *command_line)
+
+{
+ unsigned long copy_num,offset;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return;
+ }
+ ptr=parse_word (ptr,buffer);
+
+ copy_num=atol (buffer);
+
+ offset=file_system_info.first_group_desc_offset+copy_num*file_system_info.super_block.s_blocks_per_group*file_system_info.block_size;
+
+ if (offset > file_system_info.file_system_size) {
+ wprintw (command_win,"Error - Copy number out of bounds\n");refresh_command_win ();return;
+ }
+
+ group_info.copy_num=copy_num;
+ device_offset=offset+group_info.group_num*sizeof (struct ext2_group_desc);
+
+ sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer);
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+
+void type_ext2_group_desc___show (char *command_line)
+
+{
+ long group_num,temp;
+
+ temp=(device_offset-file_system_info.first_group_desc_offset) % (file_system_info.super_block.s_blocks_per_group*file_system_info.block_size);
+ group_num=temp/sizeof (struct ext2_group_desc);
+
+ show (command_line);
+
+ wmove (show_win,1,0);wprintw (show_win,"\n");wmove (show_win,2,0);
+ wprintw (show_win,"Group %ld of %ld ",group_num,file_system_info.groups_count-1);
+ wprintw (show_win,"in copy %ld ",group_info.copy_num);
+ if (group_info.copy_num==0) wprintw (show_win,"(Main copy)");
+ wprintw (show_win,"\n");refresh_show_win ();
+
+ if (group_num==0) {
+ wprintw (command_win,"Reached first group descriptor\n");
+ wrefresh (command_win);
+ }
+
+ if (group_num==file_system_info.groups_count-1) {
+ wprintw (command_win,"Reached last group descriptor\n");
+ wrefresh (command_win);
+ }
+}
+
+void type_ext2_group_desc___inode (char *command_line)
+
+{
+ long inode_offset;
+ char buffer [80];
+
+ inode_offset=type_data.u.t_ext2_group_desc.bg_inode_table;
+ sprintf (buffer,"setoffset block %ld",inode_offset);dispatch (buffer);
+ sprintf (buffer,"settype ext2_inode");dispatch (buffer);
+}
+
+void type_ext2_group_desc___blockbitmap (char *command_line)
+
+{
+ long block_bitmap_offset;
+ char buffer [80];
+
+ block_bitmap_info.entry_num=0;
+ block_bitmap_info.group_num=group_info.group_num;
+
+ block_bitmap_offset=type_data.u.t_ext2_group_desc.bg_block_bitmap;
+ sprintf (buffer,"setoffset block %ld",block_bitmap_offset);dispatch (buffer);
+ sprintf (buffer,"settype block_bitmap");dispatch (buffer);
+}
+
+void type_ext2_group_desc___inodebitmap (char *command_line)
+
+{
+ long inode_bitmap_offset;
+ char buffer [80];
+
+ inode_bitmap_info.entry_num=0;
+ inode_bitmap_info.group_num=group_info.group_num;
+
+ inode_bitmap_offset=type_data.u.t_ext2_group_desc.bg_inode_bitmap;
+ sprintf (buffer,"setoffset block %ld",inode_bitmap_offset);dispatch (buffer);
+ sprintf (buffer,"settype inode_bitmap");dispatch (buffer);
+}
+
+void type_ext2_group_desc___setactivecopy (char *command_line)
+
+{
+ struct ext2_group_desc gd;
+
+ gd=type_data.u.t_ext2_group_desc;
+ dispatch ("gocopy 0");
+ type_data.u.t_ext2_group_desc=gd;
+ dispatch ("show");
+}
diff --git a/ext2ed/init.c b/ext2ed/init.c
new file mode 100644
index 00000000..ef59b27a
--- /dev/null
+++ b/ext2ed/init.c
@@ -0,0 +1,607 @@
+/*
+
+/usr/src/ext2ed/init.c
+
+A part of the extended file system 2 disk editor.
+
+--------------------------------
+Various initialization routines.
+--------------------------------
+
+First written on: April 9 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <readline.h>
+#include <signal.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "ext2ed.h"
+
+char lines_s [80],cols_s [80];
+
+void signal_handler (void);
+
+void prepare_to_close (void)
+
+{
+ close_windows ();
+ if (device_handle!=NULL)
+ fclose (device_handle);
+ free_user_commands (&general_commands);
+ free_user_commands (&ext2_commands);
+ free_struct_descriptors ();
+}
+
+int init (void)
+
+{
+ printf ("Initializing ...\n");
+
+ if (!process_configuration_file ()) {
+ fprintf (stderr,"Error - Unable to complete configuration. Quitting.\n");
+ return (0);
+ };
+
+ general_commands.last_command=-1; /* No commands whatsoever meanwhile */
+ ext2_commands.last_command=-1;
+ add_general_commands (); /* Add the general commands, aviable always */
+ device_handle=NULL; /* Notice that our device is still not set up */
+ device_offset=-1;
+ current_type=NULL; /* No filesystem specific types yet */
+
+ remember_lifo.entries_count=0; /* Object memory is empty */
+
+ init_windows (); /* Initialize the NCURSES interface */
+ init_readline (); /* Initialize the READLINE interface */
+ init_signals (); /* Initialize the signal handlers */
+ write_access=0; /* Write access disabled */
+
+ strcpy (last_command_line,"help"); /* Show the help screen to the user */
+ dispatch ("help");
+ return (1); /* Success */
+}
+
+void add_general_commands (void)
+
+{
+ add_user_command (&general_commands,"help","EXT2ED help system",help);
+ add_user_command (&general_commands,"set","Changes a variable in the current object",set);
+ add_user_command (&general_commands,"setdevice","Selects the filesystem block device (e.g. /dev/hda1)",set_device);
+ add_user_command (&general_commands,"setoffset","Moves asynchronicly in the filesystem",set_offset);
+ add_user_command (&general_commands,"settype","Tells EXT2ED how to interpert the current object",set_type);
+ add_user_command (&general_commands,"show","Displays the current object",show);
+ add_user_command (&general_commands,"pgup","Scrolls data one page up",pgup);
+ add_user_command (&general_commands,"pgdn","Scrolls data one page down",pgdn);
+ add_user_command (&general_commands,"redraw","Redisplay the screen",redraw);
+ add_user_command (&general_commands,"remember","Saves the current position and data information",remember);
+ add_user_command (&general_commands,"recall","Gets back to the saved object position",recall);
+ add_user_command (&general_commands,"enablewrite","Enters Read/Write mode - Allows changing the filesystem",enable_write);
+ add_user_command (&general_commands,"disablewrite","Enters read only mode",disable_write);
+ add_user_command (&general_commands,"writedata","Write data back to disk",write_data);
+ add_user_command (&general_commands,"next","Moves to the next byte in hex mode",next);
+ add_user_command (&general_commands,"prev","Moves to the previous byte in hex mode",prev);
+}
+
+void add_ext2_general_commands (void)
+
+{
+ add_user_command (&ext2_commands,"super","Moves to the superblock of the filesystem",type_ext2___super);
+ add_user_command (&ext2_commands,"group","Moves to the first group descriptor",type_ext2___group);
+ add_user_command (&ext2_commands,"cd","Moves to the directory specified",type_ext2___cd);
+}
+
+int set_struct_descriptors (char *file_name)
+
+{
+ FILE *fp;
+ char current_line [500],current_word [50],*ch;
+ char variable_name [50],variable_type [20];
+ struct struct_descriptor *current_descriptor;
+
+ if ( (fp=fopen (file_name,"rt"))==NULL) {
+ wprintw (command_win,"Error - Failed to open descriptors file %s\n",file_name);
+ refresh_command_win (); return (0);
+ };
+
+ while (!feof (fp)) {
+ fgets (current_line,500,fp);
+ if (feof (fp)) break;
+ ch=parse_word (current_line,current_word);
+ if (strcmp (current_word,"struct")==0) {
+ ch=parse_word (ch,current_word);
+ current_descriptor=add_new_descriptor (current_word);
+
+ while (strchr (current_line,'{')==NULL) {
+ fgets (current_line,500,fp);
+ if (feof (fp)) break;
+ };
+ if (feof (fp)) break;
+
+ fgets (current_line,500,fp);
+
+ while (strchr (current_line,'}')==NULL) {
+ while (strchr (current_line,';')==NULL) {
+ fgets (current_line,500,fp);
+ if (strchr (current_line,'}')!=NULL) break;
+ };
+ if (strchr (current_line,'}') !=NULL) break;
+ ch=parse_word (current_line,variable_type);
+ ch=parse_word (ch,variable_name);
+ while (variable_name [strlen (variable_name)-1]!=';') {
+ strcpy (variable_type,variable_name);
+ ch=parse_word (ch,variable_name);
+ };
+ variable_name [strlen (variable_name)-1]=0;
+ add_new_variable (current_descriptor,variable_type,variable_name);
+ fgets (current_line,500,fp);
+ };
+ };
+ };
+
+ fclose (fp);
+ return (1);
+}
+
+void free_struct_descriptors (void)
+
+{
+ struct struct_descriptor *ptr,*next;
+
+ ptr=first_type;
+ while (ptr!=NULL) {
+ next=ptr->next;
+ free_user_commands (&ptr->type_commands);
+ free (ptr);
+ ptr=next;
+ }
+ first_type=last_type=current_type=NULL;
+}
+
+void free_user_commands (struct struct_commands *ptr)
+
+{
+ int i;
+
+ for (i=0;i<=ptr->last_command;i++) {
+ free (ptr->names [i]);
+ free (ptr->descriptions [i]);
+ }
+
+ ptr->last_command=-1;
+}
+
+struct struct_descriptor *add_new_descriptor (char *name)
+
+{
+ struct struct_descriptor *ptr;
+
+ if (first_type==NULL) {
+ first_type=last_type=ptr=(struct struct_descriptor *) malloc (sizeof (struct struct_descriptor));
+ if (ptr==NULL) {
+ printf ("Error - Can not allocate memory - Quitting\n");
+ exit (1);
+ }
+ ptr->prev=ptr->next=NULL;
+ strcpy (ptr->name,name);
+ ptr->length=0;
+ ptr->fields_num=0;
+ ptr->type_commands.last_command=-1;
+ fill_type_commands (ptr);
+ }
+ else {
+ ptr=(struct struct_descriptor *) malloc (sizeof (struct struct_descriptor));
+ if (ptr==NULL) {
+ printf ("Error - Can not allocate memory - Quitting\n");
+ exit (1);
+ }
+ ptr->prev=last_type;last_type->next=ptr;last_type=ptr;
+ strcpy (ptr->name,name);
+ ptr->length=0;
+ ptr->fields_num=0;
+ ptr->type_commands.last_command=-1;
+ fill_type_commands (ptr);
+ }
+ return (ptr);
+}
+
+void add_new_variable (struct struct_descriptor *ptr,char *v_type,char *v_name)
+
+{
+ short len=1;
+
+ strcpy (ptr->field_names [ptr->fields_num],v_name);
+ ptr->field_positions [ptr->fields_num]=ptr->length;
+
+ if (strcasecmp (v_type,"long")==0) len=4;
+ if (strcasecmp (v_type,"__u32")==0) len=4;
+ if (strcasecmp (v_type,"__s32")==0) len=4;
+
+ if (strcasecmp (v_type,"__u16")==0) len=2;
+ if (strcasecmp (v_type,"__s16")==0) len=2;
+ if (strcasecmp (v_type,"short")==0) len=2;
+ if (strcasecmp (v_type,"int")==0) len=2;
+
+ if (strcasecmp (v_type,"__u8")==0) len=1;
+ if (strcasecmp (v_type,"__s8")==0) len=1;
+ if (strcasecmp (v_type,"char")==0) len=1;
+
+ ptr->field_lengths [ptr->fields_num]=len;
+
+ ptr->length+=len;
+ ptr->fields_num++;
+}
+
+void fill_type_commands (struct struct_descriptor *ptr)
+
+/*
+
+Set specific type user commands.
+
+*/
+
+{
+
+ if (strcmp ((ptr->name),"file")==0) {
+ add_user_command (&ptr->type_commands,"show","Shows file data",type_file___show);
+ add_user_command (&ptr->type_commands,"inode","Returns to the inode of the current file",type_file___inode);
+ add_user_command (&ptr->type_commands,"display","Specifies data format - text or hex",type_file___display);
+ add_user_command (&ptr->type_commands,"next","Pass to next byte",type_file___next);
+ add_user_command (&ptr->type_commands,"prev","Pass to the previous byte",type_file___prev);
+ add_user_command (&ptr->type_commands,"offset","Pass to a specified byte in the current block",type_file___offset);
+ add_user_command (&ptr->type_commands,"nextblock","Pass to next file block",type_file___nextblock);
+ add_user_command (&ptr->type_commands,"prevblock","Pass to the previous file block",type_file___prevblock);
+ add_user_command (&ptr->type_commands,"block","Specify which file block to edit",type_file___block);
+ add_user_command (&ptr->type_commands,"remember","Saves the file\'s inode position for later reference",type_file___remember);
+ add_user_command (&ptr->type_commands,"set","Sets the current byte",type_file___set);
+ add_user_command (&ptr->type_commands,"writedata","Writes the current block to the disk",type_file___writedata);
+ }
+
+ if (strcmp ((ptr->name),"ext2_inode")==0) {
+ add_user_command (&ptr->type_commands,"show","Shows inode data",type_ext2_inode___show);
+ add_user_command (&ptr->type_commands,"next","Move to next inode in current block group",type_ext2_inode___next);
+ add_user_command (&ptr->type_commands,"prev","Move to next inode in current block group",type_ext2_inode___prev);
+ add_user_command (&ptr->type_commands,"group","Move to the group descriptors of the current inode table",type_ext2_inode___group);
+ add_user_command (&ptr->type_commands,"entry","Move to a specified entry in the current inode table",type_ext2_inode___entry);
+ add_user_command (&ptr->type_commands,"file","Display file data of the current inode",type_ext2_inode___file);
+ add_user_command (&ptr->type_commands,"dir","Display directory data of the current inode",type_ext2_inode___dir);
+ }
+
+ if (strcmp ((ptr->name),"dir")==0) {
+ add_user_command (&ptr->type_commands,"show","Shows current directory data",type_dir___show);
+ add_user_command (&ptr->type_commands,"inode","Returns to the inode of the current directory",type_dir___inode);
+ add_user_command (&ptr->type_commands,"next","Pass to the next directory entry",type_dir___next);
+ add_user_command (&ptr->type_commands,"prev","Pass to the previous directory entry",type_dir___prev);
+ add_user_command (&ptr->type_commands,"followinode","Follows the inode specified in this directory entry",type_dir___followinode);
+ add_user_command (&ptr->type_commands,"remember","Remember the inode of the current directory entry",type_dir___remember);
+ add_user_command (&ptr->type_commands,"cd","Changes directory relative to the current directory",type_dir___cd);
+ add_user_command (&ptr->type_commands,"entry","Moves to a specified entry in the current directory",type_dir___entry);
+ add_user_command (&ptr->type_commands,"writedata","Writes the current entry to the disk",type_dir___writedata);
+ add_user_command (&ptr->type_commands,"set","Changes a variable in the current directory entry",type_dir___set);
+ }
+
+ if (strcmp ((ptr->name),"ext2_super_block")==0) {
+ add_user_command (&ptr->type_commands,"show","Displays the super block data",type_ext2_super_block___show);
+ add_user_command (&ptr->type_commands,"gocopy","Move to another backup copy of the superblock",type_ext2_super_block___gocopy);
+ add_user_command (&ptr->type_commands,"setactivecopy","Copies the current superblock to the main superblock",type_ext2_super_block___setactivecopy);
+ }
+
+ if (strcmp ((ptr->name),"ext2_group_desc")==0) {
+ add_user_command (&ptr->type_commands,"next","Pass to the next block group decriptor",type_ext2_group_desc___next);
+ add_user_command (&ptr->type_commands,"prev","Pass to the previous group descriptor",type_ext2_group_desc___prev);
+ add_user_command (&ptr->type_commands,"entry","Pass to a specific group descriptor",type_ext2_group_desc___entry);
+ add_user_command (&ptr->type_commands,"show","Shows the current group descriptor",type_ext2_group_desc___show);
+ add_user_command (&ptr->type_commands,"inode","Pass to the inode table of the current group block",type_ext2_group_desc___inode);
+ add_user_command (&ptr->type_commands,"gocopy","Move to another backup copy of the group descriptor",type_ext2_group_desc___gocopy);
+ add_user_command (&ptr->type_commands,"blockbitmap","Show the block allocation bitmap of the current group block",type_ext2_group_desc___blockbitmap);
+ add_user_command (&ptr->type_commands,"inodebitmap","Show the inode allocation bitmap of the current group block",type_ext2_group_desc___inodebitmap);
+ add_user_command (&ptr->type_commands,"setactivecopy","Copies the current group descriptor to the main table",type_ext2_super_block___setactivecopy);
+ }
+
+ if (strcmp ((ptr->name),"block_bitmap")==0) {
+ add_user_command (&ptr->type_commands,"show","Displays the block allocation bitmap",type_ext2_block_bitmap___show);
+ add_user_command (&ptr->type_commands,"entry","Moves to a specific bit",type_ext2_block_bitmap___entry);
+ add_user_command (&ptr->type_commands,"next","Moves to the next bit",type_ext2_block_bitmap___next);
+ add_user_command (&ptr->type_commands,"prev","Moves to the previous bit",type_ext2_block_bitmap___prev);
+ add_user_command (&ptr->type_commands,"allocate","Allocates the current block",type_ext2_block_bitmap___allocate);
+ add_user_command (&ptr->type_commands,"deallocate","Deallocates the current block",type_ext2_block_bitmap___deallocate);
+ }
+
+ if (strcmp ((ptr->name),"inode_bitmap")==0) {
+ add_user_command (&ptr->type_commands,"show","Displays the inode allocation bitmap",type_ext2_inode_bitmap___show);
+ add_user_command (&ptr->type_commands,"entry","Moves to a specific bit",type_ext2_inode_bitmap___entry);
+ add_user_command (&ptr->type_commands,"next","Moves to the next bit",type_ext2_inode_bitmap___next);
+ add_user_command (&ptr->type_commands,"prev","Moves to the previous bit",type_ext2_inode_bitmap___prev);
+ add_user_command (&ptr->type_commands,"allocate","Allocates the current inode",type_ext2_inode_bitmap___allocate);
+ add_user_command (&ptr->type_commands,"deallocate","Deallocates the current inode",type_ext2_inode_bitmap___deallocate);
+ }
+
+}
+
+void add_user_command (struct struct_commands *ptr,char *name,char *description,PF callback)
+
+{
+ int num;
+
+ num=ptr->last_command;
+ if (num+1==MAX_COMMANDS_NUM) {
+ printf ("Internal Error - Can't add command %s\n",name);
+ return;
+ }
+
+ ptr->last_command=++num;
+
+ ptr->names [num]=(char *) malloc (strlen (name)+1);
+ strcpy (ptr->names [num],name);
+
+ if (*description!=0) {
+ ptr->descriptions [num]=(char *) malloc (strlen (description)+1);
+ strcpy (ptr->descriptions [num],description);
+ }
+
+ ptr->callback [num]=callback;
+}
+
+int set_file_system_info (void)
+
+{
+ int ext2_detected=0;
+ struct ext2_super_block *sb;
+
+ file_system_info.super_block_offset=1024;
+ file_system_info.file_system_size=DefaultTotalBlocks*DefaultBlockSize;
+
+ low_read ((char *) &file_system_info.super_block,sizeof (struct ext2_super_block),file_system_info.super_block_offset);
+
+ sb=&file_system_info.super_block;
+
+ if (sb->s_magic == EXT2_SUPER_MAGIC)
+ ext2_detected=1;
+
+ if (ext2_detected)
+ wprintw (command_win,"Detected extended 2 file system on device %s\n",device_name);
+ else
+ wprintw (command_win,"Warning - Extended 2 filesystem not detected on device %s\n",device_name);
+
+ if (!ext2_detected && !ForceExt2)
+ wprintw (command_win,"You may wish to use the configuration option ForceExt2 on\n");
+
+ if (ForceExt2 && !ext2_detected)
+ wprintw (command_win,"Forcing extended 2 filesystem\n");
+
+ if (ForceDefault || !ext2_detected)
+ wprintw (command_win,"Forcing default parameters\n");
+
+ refresh_command_win ();
+
+ if (ext2_detected || ForceExt2) {
+ add_ext2_general_commands ();
+ if (!set_struct_descriptors (Ext2Descriptors))
+ return (0);
+ }
+
+ if (!ForceDefault && ext2_detected) {
+
+ file_system_info.block_size=EXT2_MIN_BLOCK_SIZE << sb->s_log_block_size;
+ if (file_system_info.block_size == EXT2_MIN_BLOCK_SIZE)
+ file_system_info.first_group_desc_offset=2*EXT2_MIN_BLOCK_SIZE;
+ else
+ file_system_info.first_group_desc_offset=file_system_info.block_size;
+ file_system_info.groups_count=( sb->s_blocks_count-sb->s_first_data_block+sb->s_blocks_per_group-1) /
+ sb->s_blocks_per_group;
+
+ file_system_info.inodes_per_block=file_system_info.block_size/sizeof (struct ext2_inode);
+ file_system_info.blocks_per_group=sb->s_inodes_per_group/file_system_info.inodes_per_block;
+ file_system_info.no_blocks_in_group=sb->s_blocks_per_group;
+ file_system_info.file_system_size=(sb->s_blocks_count-1)*file_system_info.block_size;
+ }
+
+ else {
+ file_system_info.file_system_size=DefaultTotalBlocks*DefaultBlockSize;
+ file_system_info.block_size=DefaultBlockSize;
+ file_system_info.no_blocks_in_group=DefaultBlocksInGroup;
+ }
+
+ if (file_system_info.file_system_size > 2147483647) {
+ wprintw (command_win,"Sorry, filesystems bigger than 2 GB are currently not supported\n");
+ return (0);
+ }
+ return (1);
+}
+
+void init_readline (void)
+
+{
+ rl_completion_entry_function=(Function *) complete_command;
+}
+
+void init_signals (void)
+
+{
+ signal (SIGWINCH,(SignalHandler) signal_SIGWINCH_handler); /* Catch SIGWINCH */
+ signal (SIGTERM,(SignalHandler) signal_SIGTERM_handler);
+ signal (SIGSEGV,(SignalHandler) signal_SIGSEGV_handler);
+
+}
+
+void signal_SIGWINCH_handler (int sig_num)
+
+{
+ redraw_request=1; /* We will handle it in main.c */
+}
+
+void signal_SIGTERM_handler (int sig_num)
+
+{
+ prepare_to_close ();
+ printf ("Terminated due to signal %d\n",sig_num);
+ exit (1);
+}
+
+void signal_SIGSEGV_handler (int sig_num)
+
+{
+ prepare_to_close ();
+ printf ("Killed by signal %d !\n",sig_num);
+ exit (1);
+}
+
+int process_configuration_file (void)
+
+{
+ char buffer [300];
+ char option [80],value [80];
+ FILE *fp;
+
+ strcpy (buffer,VAR_DIR);
+ strcat (buffer,"/ext2ed.conf");
+
+ if ((fp=fopen (buffer,"rt"))==NULL) {
+ fprintf (stderr,"Error - Unable to open configuration file %s\n",buffer);
+ return (0);
+ }
+
+ while (get_next_option (fp,option,value)) {
+ if (strcasecmp (option,"Ext2Descriptors")==0) {
+ strcpy (Ext2Descriptors,value);
+ }
+
+ else if (strcasecmp (option,"AlternateDescriptors")==0) {
+ strcpy (AlternateDescriptors,value);
+ }
+
+ else if (strcasecmp (option,"LogFile")==0) {
+ strcpy (LogFile,value);
+ }
+
+ else if (strcasecmp (option,"LogChanges")==0) {
+ if (strcasecmp (value,"on")==0)
+ LogChanges = 1;
+ else if (strcasecmp (value,"off")==0)
+ LogChanges = 0;
+ else {
+ fprintf (stderr,"Error - Illegal value: %s %s\n",option,value);
+ fclose (fp);return (0);
+ }
+ }
+
+ else if (strcasecmp (option,"AllowChanges")==0) {
+ if (strcasecmp (value,"on")==0)
+ AllowChanges = 1;
+ else if (strcasecmp (value,"off")==0)
+ AllowChanges = 0;
+ else {
+ fprintf (stderr,"Error - Illegal value: %s %s\n",option,value);
+ fclose (fp);return (0);
+ }
+ }
+
+ else if (strcasecmp (option,"AllowMountedRead")==0) {
+ if (strcasecmp (value,"on")==0)
+ AllowMountedRead = 1;
+ else if (strcasecmp (value,"off")==0)
+ AllowMountedRead = 0;
+ else {
+ fprintf (stderr,"Error - Illegal value: %s %s\n",option,value);
+ fclose (fp);return (0);
+ }
+ }
+
+ else if (strcasecmp (option,"ForceExt2")==0) {
+ if (strcasecmp (value,"on")==0)
+ ForceExt2 = 1;
+ else if (strcasecmp (value,"off")==0)
+ ForceExt2 = 0;
+ else {
+ fprintf (stderr,"Error - Illegal value: %s %s\n",option,value);
+ fclose (fp);return (0);
+ }
+ }
+
+ else if (strcasecmp (option,"DefaultBlockSize")==0) {
+ DefaultBlockSize = atoi (value);
+ }
+
+ else if (strcasecmp (option,"DefaultTotalBlocks")==0) {
+ DefaultTotalBlocks = strtoul (value,NULL,10);
+ }
+
+ else if (strcasecmp (option,"DefaultBlocksInGroup")==0) {
+ DefaultBlocksInGroup = strtoul (value,NULL,10);
+ }
+
+ else if (strcasecmp (option,"ForceDefault")==0) {
+ if (strcasecmp (value,"on")==0)
+ ForceDefault = 1;
+ else if (strcasecmp (value,"off")==0)
+ ForceDefault = 0;
+ else {
+ fprintf (stderr,"Error - Illegal value: %s %s\n",option,value);
+ fclose (fp);return (0);
+ }
+ }
+
+ else {
+ fprintf (stderr,"Error - Unknown option: %s\n",option);
+ fclose (fp);return (0);
+ }
+ }
+
+ printf ("Configuration completed\n");
+ fclose (fp);
+ return (1);
+}
+
+int get_next_option (FILE *fp,char *option,char *value)
+
+{
+ char *ptr;
+ char buffer [600];
+
+ if (feof (fp)) return (0);
+ do{
+ if (feof (fp)) return (0);
+ fgets (buffer,500,fp);
+ } while (buffer [0]=='#' || buffer [0]=='\n');
+
+ ptr=parse_word (buffer,option);
+ ptr=parse_word (ptr,value);
+ return (1);
+}
+
+void check_mounted (char *name)
+
+{
+ FILE *fp;
+ char *ptr;
+ char current_line [500],current_word [200];
+
+ mounted=0;
+
+ if ( (fp=fopen ("/etc/mtab","rt"))==NULL) {
+ wprintw (command_win,"Error - Failed to open /etc/mtab. Assuming filesystem is mounted.\n");
+ refresh_command_win ();mounted=1;return;
+ };
+
+ while (!feof (fp)) {
+ fgets (current_line,500,fp);
+ if (feof (fp)) break;
+ ptr=parse_word (current_line,current_word);
+ if (strcasecmp (current_word,name)==0) {
+ mounted=1;fclose (fp);return;
+ }
+ };
+
+ fclose (fp);
+
+ return;
+} \ No newline at end of file
diff --git a/ext2ed/inode_com.c b/ext2ed/inode_com.c
new file mode 100644
index 00000000..d2c0638f
--- /dev/null
+++ b/ext2ed/inode_com.c
@@ -0,0 +1,436 @@
+/*
+
+/usr/src/ext2ed/inode_com.c
+
+A part of the extended file system 2 disk editor.
+
+Commands relevant to ext2_inode type.
+
+First written on: April 9 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "ext2ed.h"
+
+void type_ext2_inode___prev (char *command_line)
+
+{
+
+ char *ptr,buffer [80];
+
+ long group_num,group_offset,entry_num,block_num,first_entry,last_entry;
+ long inode_num,mult=1;
+ struct ext2_group_desc desc;
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ mult=atol (buffer);
+ }
+
+ block_num=device_offset/file_system_info.block_size;
+
+ group_num=inode_offset_to_group_num (device_offset);
+ group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+
+ low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset);
+
+ entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode);
+
+ first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1;
+ inode_num=0;
+
+ if (entry_num-mult+1>0) {
+ device_offset-=sizeof (struct ext2_inode)*mult;
+ entry_num-=mult;
+
+ sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer);
+ strcpy (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Entry out of limits\n");refresh_command_win ();
+ }
+
+ if (entry_num==0) {
+ wprintw (command_win,"Reached first inode in current group descriptor\n");
+ refresh_command_win ();
+ }
+}
+
+void type_ext2_inode___next (char *command_line)
+
+{
+
+ char *ptr,buffer [80];
+
+ long group_num,group_offset,entry_num,block_num,first_entry,last_entry;
+ long inode_num,mult=1;
+ struct ext2_group_desc desc;
+
+ ptr=parse_word (command_line,buffer);
+
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ mult=atol (buffer);
+ }
+
+
+ block_num=device_offset/file_system_info.block_size;
+
+ group_num=inode_offset_to_group_num (device_offset);
+ group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+
+ low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset);
+
+ entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode);
+
+ first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1;
+ inode_num=0;
+
+ if (entry_num+mult-1<last_entry) {
+ device_offset+=sizeof (struct ext2_inode)*mult;
+ entry_num+=mult;
+
+ sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer);
+ strcpy (buffer,"show");dispatch (buffer);
+ }
+
+ else {
+ wprintw (command_win,"Error - Entry out of limits\n");refresh_command_win ();
+ }
+
+ if (entry_num==last_entry) {
+ wprintw (command_win,"Reached last inode in current group descriptor\n");
+ refresh_command_win ();
+ }
+}
+
+
+void type_ext2_inode___show (char *command_line)
+
+{
+ struct ext2_inode *inode_ptr;
+
+ unsigned short temp;
+ int i;
+
+ long group_num,group_offset,entry_num,block_num,first_entry,last_entry,inode_num;
+ struct ext2_group_desc desc;
+
+ block_num=device_offset/file_system_info.block_size;
+
+ group_num=inode_offset_to_group_num (device_offset);
+ group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+
+ low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset);
+
+ entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode);
+ first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1;
+ inode_num=group_num*file_system_info.super_block.s_inodes_per_group+1;
+ inode_num+=entry_num;
+
+ inode_ptr=&type_data.u.t_ext2_inode;
+
+ show (command_line);
+
+ wmove (show_pad,0,40);wprintw (show_pad,"octal = %06o ",inode_ptr->i_mode);
+ for (i=6;i>=0;i-=3) {
+ temp=inode_ptr->i_mode & 0x1ff;
+ temp=temp >> i;
+ if (temp & 4)
+ wprintw (show_pad,"r");
+ else
+ wprintw (show_pad,"-");
+
+ if (temp & 2)
+ wprintw (show_pad,"w");
+ else
+ wprintw (show_pad,"-");
+
+ if (temp & 1)
+ wprintw (show_pad,"x");
+ else
+ wprintw (show_pad,"-");
+ }
+ wmove (show_pad,3,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_atime));
+ wmove (show_pad,4,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_ctime));
+ wmove (show_pad,5,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_mtime));
+ wmove (show_pad,6,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_inode.i_dtime));
+
+ wmove (show_pad,10,40);
+ temp=inode_ptr->i_flags;
+
+ if (temp & EXT2_SECRM_FL)
+ wprintw (show_pad,"s");
+ else
+ wprintw (show_pad,"-");
+
+
+ if (temp & EXT2_UNRM_FL)
+ wprintw (show_pad,"u");
+ else
+ wprintw (show_pad,"-");
+
+ if (temp & EXT2_COMPR_FL)
+ wprintw (show_pad,"c");
+ else
+ wprintw (show_pad,"-");
+
+ if (temp & EXT2_SYNC_FL)
+ wprintw (show_pad,"S");
+ else
+ wprintw (show_pad,"-");
+
+ if (temp & EXT2_IMMUTABLE_FL)
+ wprintw (show_pad,"i");
+ else
+ wprintw (show_pad,"-");
+
+ if (temp & EXT2_APPEND_FL)
+ wprintw (show_pad,"a");
+ else
+ wprintw (show_pad,"-");
+
+ if (temp & EXT2_NODUMP_FL)
+ wprintw (show_pad,"d");
+ else
+ wprintw (show_pad,"-");
+
+ refresh_show_pad ();
+
+ wmove (show_win,1,0);
+
+ wprintw (show_win,"Inode %ld of %ld. Entry %ld of %ld in group descriptor %ld.\n"
+ ,inode_num,file_system_info.super_block.s_inodes_count,entry_num,last_entry,group_num);
+
+ wprintw (show_win,"Inode type: ");
+
+ if (inode_num < EXT2_FIRST_INO) {
+ switch (inode_num) {
+ case EXT2_BAD_INO:
+ wprintw (show_win,"Bad blocks inode - ");
+ break;
+ case EXT2_ROOT_INO:
+ wprintw (show_win,"Root inode - ");
+ break;
+ case EXT2_ACL_IDX_INO:
+ wprintw (show_win,"ACL index inode - ");
+ break;
+ case EXT2_ACL_DATA_INO:
+ wprintw (show_win,"ACL data inode - ");
+ break;
+ case EXT2_BOOT_LOADER_INO:
+ wprintw (show_win,"Boot loader inode - ");
+ break;
+ case EXT2_UNDEL_DIR_INO:
+ wprintw (show_win,"Undelete directory inode - ");
+ break;
+ default:
+ wprintw (show_win,"Reserved inode - ");
+ break;
+ }
+ }
+ if (type_data.u.t_ext2_inode.i_mode==0)
+ wprintw (show_win,"Free. ");
+
+ if (S_ISREG (type_data.u.t_ext2_inode.i_mode))
+ wprintw (show_win,"File. ");
+
+ if (S_ISDIR (type_data.u.t_ext2_inode.i_mode))
+ wprintw (show_win,"Directory. ");
+
+ if (S_ISLNK (type_data.u.t_ext2_inode.i_mode)) {
+ wprintw (show_win,"Symbolic link. ");
+ wmove (show_pad,12,40);
+
+ if (inode_ptr->i_size <= 60)
+ wprintw (show_pad,"-> %s",(char *) &type_data.u.t_ext2_inode.i_block [0]);
+ else
+ wprintw (show_pad,"Slow symbolic link\n");
+ refresh_show_pad ();
+ }
+
+ if (S_ISCHR (type_data.u.t_ext2_inode.i_mode))
+ wprintw (show_win,"Character device.");
+
+ if (S_ISBLK (type_data.u.t_ext2_inode.i_mode))
+ wprintw (show_win,"Block device. ");
+
+ wprintw (show_win,"\n");refresh_show_win ();
+
+ if (entry_num==last_entry) {
+ wprintw (command_win,"Reached last inode in current group descriptor\n");
+ refresh_command_win ();
+ }
+
+ if (entry_num==first_entry) {
+ wprintw (command_win,"Reached first inode in current group descriptor\n");
+ refresh_command_win ();
+ }
+
+}
+
+void type_ext2_inode___entry (char *command_line)
+
+{
+ char *ptr,buffer [80];
+
+ long group_num,group_offset,entry_num,block_num,wanted_entry;
+ struct ext2_group_desc desc;
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) return;
+ ptr=parse_word (ptr,buffer);
+ wanted_entry=atol (buffer);
+
+ block_num=device_offset/file_system_info.block_size;
+
+ group_num=inode_offset_to_group_num (device_offset);
+ group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+
+ low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset);
+
+ entry_num=(device_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode);
+
+ if (wanted_entry > entry_num) {
+ sprintf (buffer,"next %ld",wanted_entry-entry_num);
+ dispatch (buffer);
+ }
+
+ else if (wanted_entry < entry_num) {
+ sprintf (buffer,"prev %ld",entry_num-wanted_entry);
+ dispatch (buffer);
+ }
+}
+
+void type_ext2_inode___group (char *command_line)
+
+{
+ char buffer [80];
+
+ long group_num,group_offset;
+
+ group_num=inode_offset_to_group_num (device_offset);
+ group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+
+ sprintf (buffer,"setoffset %ld",group_offset);dispatch (buffer);
+ sprintf (buffer,"settype ext2_group_desc");dispatch (buffer);
+}
+
+void type_ext2_inode___file (char *command_line)
+
+{
+ char buffer [80];
+
+ if (!S_ISREG (type_data.u.t_ext2_inode.i_mode)) {
+ wprintw (command_win,"Error - Inode type is not file\n");refresh_command_win ();
+ return;
+ }
+
+ if (!init_file_info ()) {
+ wprintw (command_win,"Error - Unable to show file\n");refresh_command_win ();
+ return;
+ }
+
+ sprintf (buffer,"settype file");dispatch (buffer);
+}
+
+void type_ext2_inode___dir (char *command_line)
+
+{
+ char buffer [80];
+
+ if (!S_ISDIR (type_data.u.t_ext2_inode.i_mode)) {
+ wprintw (command_win,"Error - Inode type is not directory\n");refresh_command_win ();
+ return;
+ }
+
+/* It is very important to init first_file_info first, as search_dir_entries relies on it */
+
+ if (!init_dir_info (&first_file_info)) {
+ wprintw (command_win,"Error - Unable to show directory\n");refresh_command_win ();
+ return;
+ }
+
+ file_info=first_file_info;
+
+ sprintf (buffer,"settype dir");dispatch (buffer);
+}
+
+long inode_offset_to_group_num (long inode_offset)
+
+{
+ int found=0;
+ struct ext2_group_desc desc;
+
+ long block_num,group_offset,group_num;
+
+ block_num=inode_offset/file_system_info.block_size;
+
+ group_offset=file_system_info.first_group_desc_offset;
+ group_num=(group_offset-file_system_info.first_group_desc_offset)/sizeof (struct ext2_group_desc);
+
+ while (!found && group_num>=0 && group_num<file_system_info.groups_count) {
+ low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset);
+ if (block_num>=desc.bg_inode_table && block_num<desc.bg_inode_table+file_system_info.blocks_per_group)
+ found=1;
+ else
+ group_offset+=sizeof (struct ext2_group_desc);
+ group_num=(group_offset-file_system_info.first_group_desc_offset)/sizeof (struct ext2_group_desc);
+ }
+
+ if (!found)
+ return (-1);
+
+ return (group_num);
+}
+
+
+
+long int inode_offset_to_inode_num (long inode_offset)
+
+{
+ long group_num,group_offset,entry_num,block_num,first_entry,last_entry,inode_num;
+ struct ext2_group_desc desc;
+
+ block_num=inode_offset/file_system_info.block_size;
+
+ group_num=inode_offset_to_group_num (inode_offset);
+ group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+
+ low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset);
+
+ entry_num=(inode_offset-desc.bg_inode_table*file_system_info.block_size)/sizeof (struct ext2_inode);
+ first_entry=0;last_entry=file_system_info.super_block.s_inodes_per_group-1;
+ inode_num=group_num*file_system_info.super_block.s_inodes_per_group+1;
+ inode_num+=entry_num;
+
+ return (inode_num);
+}
+
+long int inode_num_to_inode_offset (long inode_num)
+
+{
+ long group_num,group_offset,inode_offset,inode_entry;
+ struct ext2_group_desc desc;
+
+ inode_num--;
+
+ group_num=inode_num/file_system_info.super_block.s_inodes_per_group;
+ inode_entry=inode_num%file_system_info.super_block.s_inodes_per_group;
+ group_offset=file_system_info.first_group_desc_offset+group_num*sizeof (struct ext2_group_desc);
+ low_read ((char *) &desc,sizeof (struct ext2_group_desc),group_offset);
+
+ inode_offset=desc.bg_inode_table*file_system_info.block_size+inode_entry*sizeof (struct ext2_inode);
+
+ return (inode_offset);
+}
diff --git a/ext2ed/inodebitmap_com.c b/ext2ed/inodebitmap_com.c
new file mode 100644
index 00000000..f1fddd45
--- /dev/null
+++ b/ext2ed/inodebitmap_com.c
@@ -0,0 +1,214 @@
+/*
+
+/usr/src/ext2ed/inodebitmap_com.c
+
+A part of the extended file system 2 disk editor.
+
+-------------------------
+Handles the inode bitmap.
+-------------------------
+
+Please refer to the documentation in blockbitmap_com.c - Those two files are almost equal.
+
+First written on: July 25 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+
+void type_ext2_inode_bitmap___entry (char *command_line)
+
+{
+ unsigned long entry_num;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return;
+ }
+ ptr=parse_word (ptr,buffer);
+
+ entry_num=atol (buffer);
+
+ if (entry_num >= file_system_info.super_block.s_inodes_per_group) {
+ wprintw (command_win,"Error - Entry number out of bounds\n");refresh_command_win ();return;
+ }
+
+ inode_bitmap_info.entry_num=entry_num;
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+void type_ext2_inode_bitmap___next (char *command_line)
+
+{
+ long entry_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ entry_offset=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",inode_bitmap_info.entry_num+entry_offset);
+ dispatch (buffer);
+}
+
+void type_ext2_inode_bitmap___prev (char *command_line)
+
+{
+ long entry_offset=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ entry_offset=atol (buffer);
+ }
+
+ sprintf (buffer,"entry %ld",inode_bitmap_info.entry_num-entry_offset);
+ dispatch (buffer);
+}
+
+void type_ext2_inode_bitmap___allocate (char *command_line)
+
+{
+ long entry_num,num=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ num=atol (buffer);
+ }
+
+ entry_num=inode_bitmap_info.entry_num;
+ if (num > file_system_info.super_block.s_inodes_per_group-entry_num) {
+ wprintw (command_win,"Error - There aren't that much inodes in the group\n");
+ refresh_command_win ();return;
+ }
+
+ while (num) {
+ allocate_inode (entry_num);
+ num--;entry_num++;
+ }
+
+ dispatch ("show");
+}
+
+void type_ext2_inode_bitmap___deallocate (char *command_line)
+
+{
+ long entry_num,num=1;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr!=0) {
+ ptr=parse_word (ptr,buffer);
+ num=atol (buffer);
+ }
+
+ entry_num=inode_bitmap_info.entry_num;
+ if (num > file_system_info.super_block.s_inodes_per_group-entry_num) {
+ wprintw (command_win,"Error - There aren't that much inodes in the group\n");
+ refresh_command_win ();return;
+ }
+
+ while (num) {
+ deallocate_inode (entry_num);
+ num--;entry_num++;
+ }
+
+ dispatch ("show");
+}
+
+
+void allocate_inode (long entry_num)
+
+{
+ unsigned char bit_mask=1;
+ int byte_offset,j;
+
+ byte_offset=entry_num/8;
+ for (j=0;j<entry_num%8;j++)
+ bit_mask*=2;
+ type_data.u.buffer [byte_offset] |= bit_mask;
+}
+
+void deallocate_inode (long entry_num)
+
+{
+ unsigned char bit_mask=1;
+ int byte_offset,j;
+
+ byte_offset=entry_num/8;
+ for (j=0;j<entry_num%8;j++)
+ bit_mask*=2;
+ bit_mask^=0xff;
+
+ type_data.u.buffer [byte_offset] &= bit_mask;
+}
+
+void type_ext2_inode_bitmap___show (char *command_line)
+
+{
+ int i,j;
+ unsigned char *ptr;
+ unsigned long inode_num,entry_num;
+
+ ptr=type_data.u.buffer;
+ show_pad_info.line=0;show_pad_info.max_line=-1;
+
+ wmove (show_pad,0,0);
+ for (i=0,entry_num=0;i<file_system_info.super_block.s_inodes_per_group/8;i++,ptr++) {
+ for (j=1;j<=128;j*=2) {
+ if (entry_num==inode_bitmap_info.entry_num) {
+ wattrset (show_pad,A_REVERSE);
+ show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines/2;
+ }
+
+ if ((*ptr) & j)
+ wprintw (show_pad,"1");
+ else
+ wprintw (show_pad,"0");
+
+ if (entry_num==inode_bitmap_info.entry_num)
+ wattrset (show_pad,A_NORMAL);
+
+ entry_num++;
+ }
+ wprintw (show_pad," ");
+ if (i%8==7) {
+ wprintw (show_pad,"\n");
+ show_pad_info.max_line++;
+ }
+ }
+
+ if (i%8!=7) {
+ wprintw (show_pad,"\n");
+ show_pad_info.max_line++;
+ }
+
+ refresh_show_pad ();
+ show_info ();
+ wmove (show_win,1,0);wprintw (show_win,"Inode bitmap of block group %ld\n",inode_bitmap_info.group_num);
+
+ inode_num=1+inode_bitmap_info.entry_num+inode_bitmap_info.group_num*file_system_info.super_block.s_inodes_per_group;
+ wprintw (show_win,"Status of inode %ld - ",inode_num);
+ ptr=type_data.u.buffer+inode_bitmap_info.entry_num/8;
+ j=1;
+ for (i=inode_bitmap_info.entry_num % 8;i>0;i--)
+ j*=2;
+ if ((*ptr) & j)
+ wprintw (show_win,"Allocated\n");
+ else
+ wprintw (show_win,"Free\n");
+ refresh_show_win ();
+}
diff --git a/ext2ed/main.c b/ext2ed/main.c
new file mode 100644
index 00000000..43130c99
--- /dev/null
+++ b/ext2ed/main.c
@@ -0,0 +1,374 @@
+/*
+
+/usr/src/ext2ed/main.c
+
+A part of the extended file system 2 disk editor.
+
+------------
+Main program
+------------
+
+This file mostly contains:
+
+1. A list of global variables used through the entire program.
+2. The parser, which asks the command line from the user.
+3. The dispatcher, which analyzes the command line and calls the appropriate handler function.
+4. A command pattern matcher which is used along with the readline completion feature.
+5. A function which tells the user that an internal error has occured.
+
+First written on: March 30 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <readline.h>
+#include <history.h>
+
+#include "ext2ed.h"
+
+/* Global variables */
+
+/*
+
+Configuration file options
+
+The following variables will be set by init.c to the values selected in the user configuration file.
+They are initialized below to some logical defaults.
+
+*/
+
+
+char Ext2Descriptors [200]="ext2.descriptors"; /* The location of the ext2 filesystem object definition */
+char AlternateDescriptors [200]=""; /* We allow the user to define additional structures */
+char LogFile [200]="ext2ed.log"; /* The location of the log file - Each write will be logged there */
+int LogChanges=1; /* 1 enables logging, 0 diables logging */
+int AllowChanges=0; /* When set, the enablewrite command will fail */
+int AllowMountedRead=0; /* Behavior when trying to open a mounted filesystem read-only */
+int ForceExt2=0; /* When set, ext2 autodetection is overridden */
+int DefaultBlockSize=1024;
+unsigned long DefaultTotalBlocks=2097151;
+unsigned long DefaultBlocksInGroup=8192; /* The default values are used when an ext2 filesystem is not */
+int ForceDefault=0; /* detected, or ForceDefault is set */
+
+char last_command_line [80]; /* A simple one command cache, in addition to the readline history */
+
+char device_name [80]; /* The location of the filesystem */
+FILE *device_handle=NULL; /* This is passed to the fopen / fread ... commands */
+long device_offset; /* The current position in the filesystem */
+ /* Note that we have a 2 GB limitation */
+
+int mounted=0; /* This is set when we find that the filesystem is mounted */
+
+struct struct_commands general_commands,ext2_commands; /* Used to define the general and ext2 commands */
+struct struct_descriptor *first_type,*last_type,*current_type; /* Used to access the double linked list */
+struct struct_type_data type_data; /* The current data is sometimes stored here */
+struct struct_file_system_info file_system_info; /* Essential information on the filesystem */
+struct struct_file_info file_info,first_file_info; /* Used by file_com.c to access files */
+struct struct_group_info group_info; /* Used by group_com.c */
+struct struct_super_info super_info; /* Used by super_com.c */
+struct struct_remember_lifo remember_lifo; /* A circular memory of objects */
+struct struct_block_bitmap_info block_bitmap_info; /* Used by blockbitmap_com.c */
+struct struct_inode_bitmap_info inode_bitmap_info; /* Used by inodebitmap_com.c */
+
+int redraw_request=0; /* Is set by a signal handler to handle terminal */
+ /* screen size change. */
+int version_major=0,version_minor=1;
+char revision_date [80]="August 22 1995";
+char email_address [80]="tgud@tochnapc2.technion.ac.il";
+
+int main (void)
+
+/* We just call the parser to get commands from the user. We quit when parser returns. */
+
+{
+ if (!init ()) return (0); /* Perform some initial initialization */
+ /* Quit if failed */
+
+ parser (); /* Get and parse user commands */
+
+ prepare_to_close (); /* Do some cleanup */
+ printf ("Quitting ...\n");
+ return (1); /* And quit */
+}
+
+
+void parser (void)
+
+/*
+
+This function asks the user for a command and calls the dispatcher function, dispatch, to analyze it.
+We use the readline library function readline to read the command, hence all the usual readline keys
+are available.
+The new command is saved both in the readline's history and in our tiny one-command cache, so that
+only the enter key is needed to retype it.
+
+*/
+
+{
+ char *ptr,command_line [80];
+ int quit=0;
+
+ while (!quit) {
+
+ if (redraw_request) { /* Terminal screen size has changed */
+ dispatch ("redraw");dispatch ("show");redraw_request=0;
+ }
+
+ wmove (command_win,0,0);wclrtoeol (command_win);refresh_command_win ();
+
+ mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0); /* At last ! I spent ** days ** on this one */
+
+ /* The ncurses library optimizes cursor movement by */
+ /* keeping track of the cursor position. However, by */
+ /* using the readline library I'm breaking its */
+ /* assumptions. The double -1 arguments tell ncurses */
+ /* to disable cursor movement optimization this time. */
+ echo ();
+ ptr=readline ("ext2ed > "); /* Read the user's command line. */
+ noecho ();
+
+ strcpy (command_line,ptr); /* Readline allocated the buffer - Copy the string */
+ free (ptr); /* and free the allocated buffer */
+
+ if (*command_line != 0)
+ add_history (command_line); /* Add the non-empty command to the command histroy */
+
+ if (*command_line==0) /* If only enter was pressed, recall the last command */
+ strcpy (command_line,last_command_line);
+
+ /* Emulate readline's actions for ncurses */
+
+ mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0); /* Again, needed for correct integration of the */
+ /* ncurses and readline libraries */
+
+ werase (command_win);
+ wprintw (command_win,"ext2ed > ");wprintw (command_win,command_line);
+ wprintw (command_win,"\n");refresh_command_win ();
+
+ strcpy (last_command_line,command_line); /* Save this command in our tiny cache */
+
+ quit=dispatch (command_line); /* And call dispatch to do the actual job */
+ }
+}
+
+
+int dispatch (char *command_line)
+
+/*
+
+This is a very important function. Its task is to recieve a command name and link it to a C function.
+There are three type of commands:
+
+1. General commands - Always available and accessed through general_commands.
+2. Ext2 specific commands - Available when editing an ext2 filesystem, accessed through ext2_commands.
+3. Type specific commands - Those are changing according to the current type. The global
+ variable current_type points to the current object definition (of type struct_descriptor).
+ In it, the struct_commands entry contains the type specific commands links.
+
+Overriding is an important feature - Much like in C++ : The same command name can dispatch to different
+functions. The overriding priority is 3,2,1; That is - A type specific command will always override a
+general command. This is used through the program to allow fine tuned operation.
+
+When an handling function is found, it is called along with the command line that was passed to us. The handling
+function is then free to interpert the arguments in its own style.
+
+*/
+
+{
+ int i,found=0;
+
+ char command [80];
+
+ parse_word (command_line,command);
+
+ if (strcasecmp (command,"quit")==0) return (1);
+
+ /* 1. Search for type specific commands FIRST - Allows overriding of a general command */
+
+ if (current_type != NULL)
+ for (i=0;i<=current_type->type_commands.last_command && !found;i++) {
+ if (strcasecmp (command,current_type->type_commands.names [i])==0) {
+ (*current_type->type_commands.callback [i]) (command_line);
+ found=1;
+ }
+ }
+
+ /* 2. Now search for ext2 filesystem general commands */
+
+ if (!found)
+ for (i=0;i<=ext2_commands.last_command && !found;i++) {
+ if (strcasecmp (command,ext2_commands.names [i])==0) {
+ (*ext2_commands.callback [i]) (command_line);
+ found=1;
+ }
+ }
+
+
+ /* 3. If not found, search the general commands */
+
+ if (!found)
+ for (i=0;i<=general_commands.last_command && !found;i++) {
+ if (strcasecmp (command,general_commands.names [i])==0) {
+ (*general_commands.callback [i]) (command_line);
+ found=1;
+ }
+ }
+
+ /* 4. If not found, issue an error message and return */
+
+ if (!found) {
+ wprintw (command_win,"Error: Unknown command\n");
+ refresh_command_win ();
+ }
+
+ return (0);
+}
+
+char *parse_word (char *source,char *dest)
+
+/*
+
+This function copies the next word in source to the variable dest, ignoring whitespaces.
+It returns a pointer to the next word in source.
+It is used to split the command line into command and arguments.
+
+*/
+
+{
+ char ch,*source_ptr,*target_ptr;
+
+ if (*source==0) {
+ *dest=0;
+ return (source);
+ };
+
+ source_ptr=source;target_ptr=dest;
+ do {
+ ch=*source_ptr++;
+ } while (! (ch>' ' && ch<='z') && ch!=0);
+
+ while (ch>' ' && ch<='z') {
+ *target_ptr++=ch;
+ ch=*source_ptr++;
+ }
+
+ *target_ptr=0;
+
+ source_ptr--;
+ do {
+ ch=*source_ptr++;
+ } while (! (ch>' ' && ch<='z') && ch!=0);
+
+ return (--source_ptr);
+}
+
+char *complete_command (char *text,int state)
+
+/*
+
+text is the partial command entered by the user; We assume that it is a part of a command - I didn't write code
+for smarter completion.
+
+The state variable is an index which tells us how many possible completions we already returned to readline.
+
+We return only one possible completion or (char *) NULL if there are no more completions. This
+function will be called by readline over and over until we tell it to stop.
+
+While scanning for possible completions, we use the same priority definition which was used in dispatch.
+
+*/
+
+{
+ int state_index=-1;
+ int i,len;
+
+ len=strlen (text);
+
+ /* Is the command type specific ? */
+
+ if (current_type != NULL)
+ for (i=0;i<=current_type->type_commands.last_command;i++) {
+ if (strncmp (current_type->type_commands.names [i],text,len)==0) {
+ state_index++;
+ if (state==state_index) {
+ return (dupstr (current_type->type_commands.names [i]));
+ }
+ }
+ }
+
+ /* No, pehaps ext2 specific command then ? */
+
+ for (i=0;i<=ext2_commands.last_command;i++) {
+ if (strncmp (ext2_commands.names [i],text,len)==0) {
+ state_index++;
+ if (state==state_index)
+ return (dupstr (ext2_commands.names [i]));
+ }
+ }
+
+
+ /* Check for a general command */
+
+ for (i=0;i<=general_commands.last_command;i++) {
+ if (strncmp (general_commands.names [i],text,len)==0) {
+ state_index++;
+ if (state==state_index)
+ return (dupstr (general_commands.names [i]));
+ }
+ }
+
+ /* quit is handled differently */
+
+ if (strncmp ("quit",text,len)==0) {
+ state_index++;
+ if (state==state_index)
+ return (dupstr ("quit"));
+ }
+
+ /* No more completions */
+
+ return ((char *) NULL);
+}
+
+char *dupstr (char *src)
+
+/*
+
+Nothing special - Just allocates enough space and copy the string.
+
+*/
+
+{
+ char *ptr;
+
+ ptr=(char *) malloc (strlen (src)+1);
+ strcpy (ptr,src);
+ return (ptr);
+}
+
+#ifdef DEBUG
+
+void internal_error (char *description,char *source_name,char *function_name)
+
+/*
+
+This function reports an internal error. It is almost not used. One place in which I do check for internal
+errors is disk.c.
+
+We just report the error, and try to continue ...
+
+*/
+
+{
+ wprintw (command_win,"Internal error - Found by source: %s.c , function: %s\n",source_name,function_name);
+ wprintw (command_win,"\t%s\n",description);
+ wprintw (command_win,"Press enter to (hopefully) continue\n");
+ refresh_command_win ();getch ();werase (command_win);
+}
+
+#endif \ No newline at end of file
diff --git a/ext2ed/super_com.c b/ext2ed/super_com.c
new file mode 100644
index 00000000..0541ff3b
--- /dev/null
+++ b/ext2ed/super_com.c
@@ -0,0 +1,159 @@
+/*
+
+/usr/src/ext2ed/super_com.c
+
+A part of the extended file system 2 disk editor.
+
+----------------------
+Handles the superblock
+----------------------
+
+First written on: April 9 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "ext2ed.h"
+
+void type_ext2_super_block___show (char *command_line)
+
+{
+ struct ext2_super_block *super;
+ super=&type_data.u.t_ext2_super_block;
+
+ show (command_line);
+
+ if (super->s_blocks_count != 0) {
+ wmove (show_pad,2,40);wprintw (show_pad,"%2.2f%%",100*(float) super->s_r_blocks_count/ (float) super->s_blocks_count);
+ wmove (show_pad,3,40);wprintw (show_pad,"%2.2f%%",100*(float) super->s_free_blocks_count/ (float) super->s_blocks_count);
+ }
+
+ if (super->s_inodes_count != 0) {
+ wmove (show_pad,4,40);wprintw (show_pad,"%2.2f%%",100*(float) super->s_free_inodes_count/ (float) super->s_inodes_count);
+ }
+
+ wmove (show_pad,6,40);
+ switch (super->s_log_block_size) {
+ case 0: wprintw (show_pad,"1024 bytes");break;
+ case 1: wprintw (show_pad,"2048 bytes");break;
+ case 2: wprintw (show_pad,"4096 bytes");break;
+ }
+ wmove (show_pad,11,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_mtime));
+ wmove (show_pad,12,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_wtime));
+ wmove (show_pad,19,40);wprintw (show_pad,"%s",ctime ((time_t *) &type_data.u.t_ext2_super_block.s_lastcheck));
+ wmove (show_pad,15,40);
+
+ switch (type_data.u.t_ext2_super_block.s_magic) {
+ case EXT2_SUPER_MAGIC:
+ wprintw (show_pad,"ext2 >= 0.2B");
+ break;
+ case EXT2_PRE_02B_MAGIC:
+ wprintw (show_pad,"ext2 < 0.2B (not supported)");
+ break;
+ default:
+ wprintw (show_pad,"Unknown");
+ break;
+ }
+
+ wmove (show_pad,16,40);
+ if (type_data.u.t_ext2_super_block.s_state & 0x1)
+ wprintw (show_pad,"clean ");
+ else
+ wprintw (show_pad,"not clean ");
+
+ if (type_data.u.t_ext2_super_block.s_state & 0x2)
+ wprintw (show_pad,"with errors ");
+ else
+ wprintw (show_pad,"with no errors");
+
+ wmove (show_pad,17,40);
+
+ switch (type_data.u.t_ext2_super_block.s_errors) {
+ case EXT2_ERRORS_CONTINUE:
+ wprintw (show_pad,"Continue");
+ break;
+ case EXT2_ERRORS_RO:
+ wprintw (show_pad,"Remount read only");
+ break;
+ case EXT2_ERRORS_PANIC:
+ wprintw (show_pad,"Issue kernel panic");
+ break;
+ default:
+ wprintw (show_pad,"Unknown");
+ break;
+ }
+
+ wmove (show_pad,21,40);
+
+ switch (type_data.u.t_ext2_super_block.s_creator_os) {
+
+ case EXT2_OS_LINUX:
+ wprintw (show_pad,"Linux :-)");
+ break;
+
+ case EXT2_OS_HURD:
+ wprintw (show_pad,"Hurd");
+ break;
+
+ case EXT2_OS_MASIX:
+ wprintw (show_pad,"Masix");
+ break;
+
+ default:
+ wprintw (show_pad,"Unknown");
+ break;
+ }
+
+ refresh_show_pad ();
+
+ wmove (show_win,1,0);wprintw (show_win,"\n");wmove (show_win,2,0);
+ wprintw (show_win,"Superblock copy %ld ",super_info.copy_num);
+ if (super_info.copy_num==0)
+ wprintw (show_win,"(main copy)");
+ wprintw (show_win,"\n");
+ refresh_show_win ();
+}
+
+void type_ext2_super_block___gocopy (char *command_line)
+
+{
+ unsigned long copy_num,offset;
+ char *ptr,buffer [80];
+
+ ptr=parse_word (command_line,buffer);
+ if (*ptr==0) {
+ wprintw (command_win,"Error - No argument specified\n");refresh_command_win ();return;
+ }
+ ptr=parse_word (ptr,buffer);
+
+ copy_num=atol (buffer);
+
+ offset=file_system_info.super_block_offset+copy_num*file_system_info.no_blocks_in_group*file_system_info.block_size;
+
+ if (offset > file_system_info.file_system_size) {
+ wprintw (command_win,"Error - Copy number out of bounds\n");refresh_command_win ();return;
+ }
+
+ super_info.copy_num=copy_num;
+ device_offset=offset;
+
+ sprintf (buffer,"setoffset %ld",device_offset);dispatch (buffer);
+ strcpy (buffer,"show");dispatch (buffer);
+}
+
+void type_ext2_super_block___setactivecopy (char *command_line)
+
+{
+ struct ext2_super_block sb;
+
+ sb=type_data.u.t_ext2_super_block;
+ dispatch ("gocopy 0");
+ type_data.u.t_ext2_super_block=sb;
+ dispatch ("show");
+}
diff --git a/ext2ed/win.c b/ext2ed/win.c
new file mode 100644
index 00000000..09ee22dd
--- /dev/null
+++ b/ext2ed/win.c
@@ -0,0 +1,169 @@
+/*
+
+/usr/src/ext2ed/win.c
+
+A part of the extended file system 2 disk editor.
+
+--------------------------------------------------------
+Window management - Interfacing with the ncurses library
+--------------------------------------------------------
+
+First written on: April 17 1995
+
+Copyright (C) 1995 Gadi Oxman
+
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "ext2ed.h"
+
+struct struct_pad_info show_pad_info;
+WINDOW *title_win,*show_win,*command_win,*show_pad;
+
+void init_windows (void)
+
+{
+ char title_string [80];
+
+ initscr ();
+
+ if (LINES<TITLE_WIN_LINES+SHOW_WIN_LINES+COMMAND_WIN_LINES+3) {
+ printf ("Sorry, your terminal screen is too small\n");
+ printf ("Error - Can not initialize windows\n");
+ exit (1);
+ }
+
+ title_win=newwin (TITLE_WIN_LINES,COLS,0,0);
+ show_win=newwin (SHOW_WIN_LINES,COLS,TITLE_WIN_LINES,0);
+ show_pad=newpad (SHOW_PAD_LINES,SHOW_PAD_COLS);
+ command_win=newwin (COMMAND_WIN_LINES,COLS,LINES-COMMAND_WIN_LINES,0);
+
+ if (title_win==NULL || show_win==NULL || show_pad==NULL || command_win==NULL) {
+ printf ("Error - Not enough memory - Can not initialize windows\n");exit (1);
+ }
+
+ box (title_win,0,0);
+ sprintf (title_string,"EXT2ED - Extended-2 File System editor ver %d.%d (%s)",version_major,version_minor,revision_date);
+ wmove (title_win,TITLE_WIN_LINES/2,(COLS-strlen (title_string))/2);
+ wprintw (title_win,title_string);
+
+#ifdef OLD_NCURSES
+ wattrset (show_win,A_NORMAL);werase (show_win);
+#else
+ wbkgdset (show_win,A_REVERSE);werase (show_win);
+#endif
+ show_pad_info.line=0;show_pad_info.col=0;
+ show_pad_info.display_lines=LINES-TITLE_WIN_LINES-SHOW_WIN_LINES-COMMAND_WIN_LINES-2;
+ show_pad_info.display_cols=COLS;
+ show_pad_info.max_line=show_pad_info.display_lines-1;show_pad_info.max_col=show_pad_info.display_cols-1;
+ show_pad_info.disable_output=0;
+
+ scrollok (command_win,TRUE);
+
+ refresh_title_win ();refresh_show_win ();refresh_show_pad ();refresh_command_win ();
+}
+
+void refresh_title_win (void)
+
+{
+ wrefresh (title_win);
+}
+
+void refresh_show_win (void)
+
+{
+ int current_page,total_pages;
+
+ current_page=show_pad_info.line/show_pad_info.display_lines+1;
+ if (show_pad_info.line%show_pad_info.display_lines)
+ current_page++;
+ total_pages=show_pad_info.max_line/show_pad_info.display_lines+1;
+
+ wmove (show_win,2,COLS-18);
+ wprintw (show_win,"Page %d of %d\n",current_page,total_pages);
+
+ wmove (show_win,2,COLS-18);
+ wrefresh (show_win);
+}
+
+
+void refresh_show_pad (void)
+
+{
+ int left,top,right,bottom,i;
+
+ if (show_pad_info.disable_output)
+ return;
+
+ if (show_pad_info.max_line < show_pad_info.display_lines-1) {
+ for (i=show_pad_info.max_line+1;i<show_pad_info.display_lines;i++) {
+ wmove (show_pad,i,0);wprintw (show_pad,"\n");
+ }
+ }
+ left=0;right=show_pad_info.display_cols-1;
+ top=TITLE_WIN_LINES+SHOW_WIN_LINES+1;bottom=top+show_pad_info.display_lines-1;
+
+ if (show_pad_info.line > show_pad_info.max_line-show_pad_info.display_lines+1)
+ show_pad_info.line=show_pad_info.max_line-show_pad_info.display_lines+1;
+
+ if (show_pad_info.line < 0)
+ show_pad_info.line=0;
+
+#ifdef OLD_NCURSES
+ prefresh (show_pad,show_pad_info.line,show_pad_info.col,top,left,show_pad_info.display_lines-1,show_pad_info.display_cols-1);
+#else
+ prefresh (show_pad,show_pad_info.line,show_pad_info.col,top,left,top+show_pad_info.display_lines-1,left+show_pad_info.display_cols-1);
+#endif
+}
+
+void refresh_command_win (void)
+
+{
+ wrefresh (command_win);
+}
+
+void close_windows (void)
+
+{
+ echo ();
+
+ delwin (title_win);
+ delwin (command_win);
+ delwin (show_win);
+ delwin (show_pad);
+
+ endwin ();
+}
+
+void show_info (void)
+
+{
+ int block_num,block_offset;
+
+ block_num=device_offset/file_system_info.block_size;
+ block_offset=device_offset%file_system_info.block_size;
+
+ wmove (show_win,0,0);
+ wprintw (show_win,"Offset %-3ld in block %ld. ",block_offset,block_num);
+ if (current_type != NULL)
+ wprintw (show_win,"Type: %s\n",current_type->name);
+ else
+ wprintw (show_win,"Type: %s\n","none");
+
+ refresh_show_win ();
+}
+
+
+void redraw_all (void)
+
+{
+ close_windows ();
+ init_windows ();
+
+ wmove (command_win,0,0);
+ mvcur (-1,-1,LINES-COMMAND_WIN_LINES,0);
+
+} \ No newline at end of file