/* save-cwd.c -- Save and restore current working directory.
- Copyright (C) 1995, 1997, 1998 Free Software Foundation, Inc.
+ Copyright (C) 1995, 1997, 1998, 2003, 2004 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
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>. */
+/* Written by Jim Meyering. */
#if HAVE_CONFIG_H
# include "config.h"
#endif
+#include <stdbool.h>
#include <stdio.h>
-
-#ifdef STDC_HEADERS
-# include <stdlib.h>
-#endif
+#include <stdlib.h>
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <errno.h>
-#ifndef errno
-extern int errno;
+
+#ifndef O_DIRECTORY
+# define O_DIRECTORY 0
#endif
#include "save-cwd.h"
-#include "error.h"
-
-char *xgetcwd PARAMS ((void));
+#include "xgetcwd.h"
/* Record the location of the current working directory in CWD so that
the program may change to other directories and later use restore_cwd
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. */
+ called, but doing so is ok. Otherwise, return zero.
+
+ The `raison d'etre' for this interface is that some systems lack
+ support for fchdir, and getcwd is not robust or as efficient.
+ So, we prefer to use the open/fchdir approach, but fall back on
+ getcwd if necessary. Some systems lack fchdir altogether: OS/2,
+ Cygwin (as of March 2003), SCO Xenix. At least SunOS 4 and Irix 5.3
+ provide the function, yet it doesn't work for partitions on which
+ auditing is enabled. */
int
save_cwd (struct saved_cwd *cwd)
{
- static int have_working_fchdir = 1;
+ static bool have_working_fchdir = true;
cwd->desc = -1;
cwd->name = NULL;
if (have_working_fchdir)
{
#if HAVE_FCHDIR
- cwd->desc = open (".", O_RDONLY);
+ cwd->desc = open (".", O_RDONLY | O_DIRECTORY);
+ if (cwd->desc < 0)
+ cwd->desc = open (".", O_WRONLY | O_DIRECTORY);
if (cwd->desc < 0)
{
- error (0, errno, "cannot open current directory");
- return 1;
+ cwd->name = xgetcwd ();
+ return cwd->name ? 0 : -1;
}
# if __sun__ || sun
- /* On SunOS 4, fchdir returns EINVAL if accounting is enabled,
- so we have to fall back to chdir. */
+ /* On SunOS 4 and IRIX 5.3, fchdir returns EINVAL when auditing
+ 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;
+ have_working_fchdir = false;
}
else
{
- error (0, errno, "current directory");
+ int saved_errno = errno;
close (cwd->desc);
cwd->desc = -1;
- return 1;
+ errno = saved_errno;
+ return -1;
}
}
# endif /* __sun__ || sun */
#else
# define fchdir(x) (abort (), 0)
- have_working_fchdir = 0;
+ have_working_fchdir = false;
#endif
}
{
cwd->name = xgetcwd ();
if (cwd->name == NULL)
- {
- error (0, errno, "cannot get current directory");
- return 1;
- }
+ return -1;
}
return 0;
}
/* Change to recorded location, CWD, in directory hierarchy.
- If "saved working directory", NULL))
- */
+ Upon failure, return -1 (errno is set by chdir or fchdir).
+ Upon success, return zero. */
int
-restore_cwd (const struct saved_cwd *cwd, const char *dest, const char *from)
+restore_cwd (const struct saved_cwd *cwd)
{
- 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;
+ if (0 <= cwd->desc)
+ return fchdir (cwd->desc);
+ else
+ return chdir (cwd->name);
}
void