coreutils/lib/rename.c
1995-05-19 15:23:18 +00:00

104 lines
2.6 KiB
C

/* rename.c -- BSD compatible directory function for System V
Copyright (C) 1988, 1990 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 2, 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. */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#ifdef STAT_MACROS_BROKEN
#undef S_ISDIR
#endif /* STAT_MACROS_BROKEN. */
#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 (from, to)
char *from;
char *to;
{
struct stat from_stats, to_stats;
int pid, status;
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;
}
if (S_ISDIR (from_stats.st_mode))
{
/* Need a setuid root process to link and unlink directories. */
pid = fork ();
switch (pid)
{
case -1: /* Error. */
error (1, errno, "cannot fork");
case 0: /* Child. */
execl (MVDIR, "mvdir", from, to, (char *) 0);
error (255, errno, "cannot run `%s'", MVDIR);
default: /* Parent. */
while (wait (&status) != pid)
/* Do nothing. */ ;
errno = 0; /* mvdir printed the system error message. */
if (status)
return -1;
}
}
else
{
if (link (from, to))
return -1;
if (unlink (from) && errno != ENOENT)
{
unlink (to);
return -1;
}
}
return 0;
}