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authorChris Wilson <chris+github@qwirx.com>2006-12-03 10:29:01 +0000
committerChris Wilson <chris+github@qwirx.com>2006-12-03 10:29:01 +0000
commit4008ada60d5fdf946a8c5e5aa03ea0f01172335d (patch)
tree05f2a239747cf45595ba456eb848917ea93ca553
parent7400293edc37751f109afc8a5516108b61474374 (diff)
Added a header file for including in test/bbackupd/testbbackupd.cpp and
other modules which might need intercepts in future. Added opendir/readdir and lstat hook capability. (refs #3, refs #9)
-rw-r--r--lib/intercept/intercept.cpp175
-rw-r--r--lib/intercept/intercept.h42
2 files changed, 217 insertions, 0 deletions
diff --git a/lib/intercept/intercept.cpp b/lib/intercept/intercept.cpp
index 21220cc9..a4dfcc37 100644
--- a/lib/intercept/intercept.cpp
+++ b/lib/intercept/intercept.cpp
@@ -9,6 +9,8 @@
#include "Box.h"
+#include "intercept.h"
+
#ifdef HAVE_SYS_SYSCALL_H
#include <sys/syscall.h>
#endif
@@ -21,6 +23,10 @@
#include <errno.h>
+#ifdef HAVE_DLFCN_H
+#include <dlfcn.h>
+#endif
+
#ifndef PLATFORM_CLIB_FNS_INTERCEPTION_IMPOSSIBLE
#if !defined(HAVE_SYSCALL) && !defined(HAVE___SYSCALL) && !defined(HAVE___SYSCALL_NEED_DEFN)
@@ -317,4 +323,173 @@ lseek(int fildes, off_t offset, int whence)
return r;
}
+static opendir_t* opendir_real = NULL;
+static readdir_t* readdir_real = NULL;
+static readdir_t* readdir_hook = NULL;
+static closedir_t* closedir_real = NULL;
+static lstat_t* lstat_real = NULL;
+static lstat_t* lstat_hook = NULL;
+static const char* lstat_file = NULL;
+
+void intercept_setup_readdir_hook(const char *dirname, readdir_t hookfn)
+{
+ if (hookfn != NULL && dirname == NULL)
+ {
+ dirname = intercept_filename;
+ }
+
+ if (hookfn != NULL)
+ {
+ TRACE2("readdir hooked to %p for %s\n", hookfn, dirname);
+ }
+ else
+ {
+ TRACE2("readdir unhooked from %p for %s\n", readdir_hook,
+ intercept_filename);
+ }
+
+ intercept_filename = dirname;
+ readdir_hook = hookfn;
+}
+
+void intercept_setup_lstat_hook(const char *filename, lstat_t hookfn)
+{
+ /*
+ if (hookfn != NULL)
+ {
+ TRACE2("lstat hooked to %p for %s\n", hookfn, filename);
+ }
+ else
+ {
+ TRACE2("lstat unhooked from %p for %s\n", lstat_hook,
+ lstat_file);
+ }
+ */
+
+ lstat_file = filename;
+ lstat_hook = hookfn;
+}
+
+extern "C"
+DIR *opendir(const char *dirname)
+{
+ if (opendir_real == NULL)
+ {
+ opendir_real = (opendir_t*)(dlsym(RTLD_NEXT, "opendir"));
+ }
+
+ if (opendir_real == NULL)
+ {
+ perror("cannot find real opendir");
+ return NULL;
+ }
+
+ DIR* r = opendir_real(dirname);
+
+ if(readdir_hook != NULL && intercept_filedes == -1 &&
+ strcmp(intercept_filename, dirname) == 0)
+ {
+ intercept_filedes = dirfd(r);
+ //printf("Found file to intercept, h = %d\n", r);
+ }
+
+ return r;
+}
+
+extern "C"
+struct dirent *readdir(DIR *dir)
+{
+ if (readdir_hook != NULL && dirfd(dir) == intercept_filedes)
+ {
+ return readdir_hook(dir);
+ }
+
+ if (readdir_real == NULL)
+ {
+ #if readdir == readdir64
+ readdir_real = (readdir_t*)(dlsym(RTLD_NEXT, "readdir64"));
+ #else
+ readdir_real = (readdir_t*)(dlsym(RTLD_NEXT, "readdir"));
+ #endif
+ }
+
+ if (readdir_real == NULL)
+ {
+ perror("cannot find real readdir");
+ return NULL;
+ }
+
+ return readdir_real(dir);
+}
+
+extern "C"
+int closedir(DIR *dir)
+{
+ if (dirfd(dir) == intercept_filedes)
+ {
+ intercept_filedes = -1;
+ }
+
+ if (closedir_real == NULL)
+ {
+ closedir_real = (closedir_t*)(dlsym(RTLD_NEXT, "closedir"));
+ }
+
+ if (closedir_real == NULL)
+ {
+ perror("cannot find real closedir");
+ errno = ENOSYS;
+ return -1;
+ }
+
+ return closedir_real(dir);
+}
+
+extern "C" int
+#ifdef LINUX_WEIRD_LSTAT
+__lxstat(int ver, const char *file_name, STAT_STRUCT *buf)
+#else
+lstat(const char *file_name, STAT_STRUCT *buf)
+#endif
+{
+ if (lstat_real == NULL)
+ {
+ #ifdef LINUX_WEIRD_LSTAT
+ #if __lxstat == __lxstat64
+ lstat_real = (lstat_t*)(dlsym(RTLD_NEXT, "__lxstat64"));
+ #else
+ lstat_real = (lstat_t*)(dlsym(RTLD_NEXT, "__lxstat"));
+ #endif
+ #else
+ #if lstat == lstat64
+ lstat_real = (lstat_t*)(dlsym(RTLD_NEXT, "lstat64"));
+ #else
+ lstat_real = (lstat_t*)(dlsym(RTLD_NEXT, "lstat"));
+ #endif
+ #endif
+ }
+
+ if (lstat_real == NULL)
+ {
+ perror("cannot find real lstat");
+ errno = ENOSYS;
+ return -1;
+ }
+
+ if (lstat_hook == NULL || strcmp(file_name, lstat_file) != 0)
+ {
+ #ifdef LINUX_WEIRD_LSTAT
+ return lstat_real(ver, file_name, buf);
+ #else
+ return lstat_real(file_name, buf);
+ #endif
+ }
+
+ #ifdef LINUX_WEIRD_LSTAT
+ return lstat_hook(ver, file_name, buf);
+ #else
+ return lstat_hook(file_name, buf);
+ #endif
+}
+
#endif // n PLATFORM_CLIB_FNS_INTERCEPTION_IMPOSSIBLE
diff --git a/lib/intercept/intercept.h b/lib/intercept/intercept.h
new file mode 100644
index 00000000..b1122434
--- /dev/null
+++ b/lib/intercept/intercept.h
@@ -0,0 +1,42 @@
+// --------------------------------------------------------------------------
+//
+// File
+// Name: intercept.h
+// Purpose: Syscall interception code for unit tests
+// Created: 2006/11/29
+//
+// --------------------------------------------------------------------------
+
+#ifndef INTERCEPT_H
+#define INTERCEPT_H
+
+#include <dirent.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+extern "C"
+{
+ typedef DIR *(opendir_t) (const char *name);
+ typedef struct dirent *(readdir_t) (DIR *dir);
+ typedef struct dirent *(readdir_t) (DIR *dir);
+ typedef int (closedir_t)(DIR *dir);
+#if defined __GNUC__ && __GNUC__ >= 2
+#define LINUX_WEIRD_LSTAT
+#define STAT_STRUCT struct stat /* should be stat64 */
+ typedef int (lstat_t) (int ver, const char *file_name,
+ STAT_STRUCT *buf);
+#else
+#define STAT_STRUCT struct stat
+ typedef int (lstat_t) (const char *file_name,
+ STAT_STRUCT *buf);
+#endif
+}
+
+void intercept_setup_error(const char *filename, unsigned int errorafter,
+ int errortoreturn, int syscalltoerror);
+
+void intercept_setup_readdir_hook(const char *dirname, readdir_t hookfn);
+void intercept_setup_lstat_hook (const char *filename, lstat_t hookfn);
+
+#endif // !INTERCEPT_H