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/* BSD compatible rename and directory rename function.
Copyright (C) 1988, 1990, 1999 Free Software Foundation, Inc.
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 3, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#if HAVE_CONFIG_H
# include <config.h>
#endif
/* Needed for some prototypes under OS/2. */
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#if STAT_MACROS_BROKEN
# undef S_ISDIR
#endif
#if !defined(S_ISDIR) && defined(S_IFDIR)
# define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#endif
/* Rename file FROM to file TO.
Return 0 if successful, -1 if not. */
int
rename (const char *from, const char *to)
{
struct stat from_stats, to_stats;
if (stat (from, &from_stats))
return -1;
/* Be careful not to unlink `from' if it happens to be equal to `to' or
(on filesystems that silently truncate filenames after 14 characters)
if `from' and `to' share the significant characters. */
if (stat (to, &to_stats))
{
if (errno != ENOENT)
return -1;
}
else
{
if ((from_stats.st_dev == to_stats.st_dev)
&& (from_stats.st_ino == to_stats.st_ino))
/* `from' and `to' designate the same file on that filesystem. */
return 0;
if (unlink (to) && errno != ENOENT)
return -1;
}
#ifdef MVDIR
/* If MVDIR is defined, it should be the full filename of a setuid root
program able to link and unlink directories. If MVDIR is not defined,
then the capability of renaming directories may be missing. */
if (S_ISDIR (from_stats.st_mode))
{
/* Need a setuid root process to link and unlink directories. */
int status;
pid_t pid = fork ();
switch (pid)
{
case -1: /* Error. */
return -1; /* errno already set */
case 0: /* Child. */
execl (MVDIR, "mvdir", from, to, (char *) 0);
_exit (1);
default: /* Parent. */
while (wait (&status) != pid)
/* Do nothing. */ ;
if (status)
{
/* MVDIR failed. */
errno = EIO;
return -1;
}
}
}
else
#endif /* MVDIR */
#if HAVE_LINK
/* This is typically under Unix. */
{
if (link (from, to))
return -1;
if (unlink (from) && errno != ENOENT)
{
unlink (to);
return -1;
}
}
#elif HAVE_RENAME
/* OS/2 for instance lacks `link' (but has `unlink'), and does provide
`rename'. Nevertheless the semantics of OS/2 rename differs from
that of Unix', in that rename (FROM, TO) fails if TO exists.
Here, yet we know FROM exists, and TO was unlinked. */
/* Make sure to call the system's rename. */
#undef rename
{
if (rename (from, to))
return -1;
}
#else /* !HAVE_LINK && !HAVE_RENAME */
/* There are no ways to implement rename. */
#error
#endif /* !HAVE_LINK && !HAVE_RENAME */
return 0;
}
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