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/* save-cwd.c -- Save and restore current working directory.
Copyright (C) 1995, 1997, 1998 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* Written by Jim Meyering <meyering@na-net.ornl.gov>. */
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
#endif
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#if HAVE_FCNTL_H
# include <fcntl.h>
#else
# include <sys/file.h>
#endif
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#ifndef O_DIRECTORY
# define O_DIRECTORY 0
#endif
#include "save-cwd.h"
#include "error.h"
char *xgetcwd PARAMS ((void));
/* Record the location of the current working directory in CWD so that
the program may change to other directories and later use restore_cwd
to return to the recorded location. This function may allocate
space using malloc (via xgetcwd) or leave a file descriptor open;
use free_cwd to perform the necessary free or close. Upon failure,
no memory is allocated, any locally opened file descriptors are
closed; return non-zero -- in that case, free_cwd need not be
called, but doing so is ok. Otherwise, return zero. */
int
save_cwd (struct saved_cwd *cwd)
{
static int have_working_fchdir = 1;
cwd->desc = -1;
cwd->name = NULL;
if (have_working_fchdir)
{
#if HAVE_FCHDIR
cwd->desc = open (".", O_RDONLY | O_DIRECTORY);
if (cwd->desc < 0)
{
error (0, errno, "cannot open current directory");
return 1;
}
# if __sun__ || sun
/* On SunOS 4, fchdir returns EINVAL if accounting is enabled,
so we have to fall back to chdir. */
if (fchdir (cwd->desc))
{
if (errno == EINVAL)
{
close (cwd->desc);
cwd->desc = -1;
have_working_fchdir = 0;
}
else
{
error (0, errno, "current directory");
close (cwd->desc);
cwd->desc = -1;
return 1;
}
}
# endif /* __sun__ || sun */
#else
# define fchdir(x) (abort (), 0)
have_working_fchdir = 0;
#endif
}
if (!have_working_fchdir)
{
cwd->name = xgetcwd ();
if (cwd->name == NULL)
{
error (0, errno, "cannot get current directory");
return 1;
}
}
return 0;
}
/* Change to recorded location, CWD, in directory hierarchy.
If "saved working directory", NULL))
*/
int
restore_cwd (const struct saved_cwd *cwd, const char *dest, const char *from)
{
int fail = 0;
if (cwd->desc >= 0)
{
if (fchdir (cwd->desc))
{
error (0, errno, "cannot return to %s%s%s",
(dest ? dest : "saved working directory"),
(from ? " from " : ""),
(from ? from : ""));
fail = 1;
}
}
else if (chdir (cwd->name) < 0)
{
error (0, errno, "%s", cwd->name);
fail = 1;
}
return fail;
}
void
free_cwd (struct saved_cwd *cwd)
{
if (cwd->desc >= 0)
close (cwd->desc);
if (cwd->name)
free (cwd->name);
}
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