/* save-cwd.c -- Save and restore current working directory.
- Copyright (C) 1995 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ Copyright (C) 1995, 1997-1998, 2003-2006, 2009-2013 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.
+ the Free Software Foundation; either version 3 of the License, 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
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
-/* Written by Jim Meyering <meyering@na-net.ornl.gov>. */
+/* Written by Jim Meyering. */
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
+#include <config.h>
-#include <stdio.h>
+#include "save-cwd.h"
-#ifdef STDC_HEADERS
-# include <stdlib.h>
-#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif
+#include "chdir-long.h"
+#include "unistd--.h"
+#include "cloexec.h"
-#ifdef HAVE_FCNTL_H
-# include <fcntl.h>
+#if GNULIB_FCNTL_SAFER
+# include "fcntl--.h"
#else
-# include <sys/file.h>
-#endif
-
-#include <errno.h>
-# ifndef errno
-extern int errno;
+# define GNULIB_FCNTL_SAFER 0
#endif
-#include "save-cwd.h"
-#include "error.h"
-
-char *xgetcwd __P((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;
+ space using malloc (via getcwd) 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. */
+ called, but doing so is ok. Otherwise, return zero.
+
+ The _raison d'etre_ for this interface is that the working directory
+ is sometimes inaccessible, and getcwd is not robust or as efficient.
+ So, we prefer to use the open/fchdir approach, but fall back on
+ getcwd if necessary. This module works for most cases with just
+ the getcwd-lgpl module, but to be truly robust, use the getcwd module.
+
+ Some systems lack fchdir altogether: e.g., OS/2, pre-2001 Cygwin,
+ SCO Xenix. Also, SunOS 4 and Irix 5.3 provide the function, yet it
+ doesn't work for partitions on which auditing is enabled. If
+ you're still using an obsolete system with these problems, please
+ send email to the maintainer of this code. */
int
-save_cwd (cwd)
- struct saved_cwd *cwd;
+save_cwd (struct saved_cwd *cwd)
{
- static int have_working_fchdir = 1;
-
- cwd->desc = -1;
cwd->name = NULL;
- if (have_working_fchdir)
+ cwd->desc = open (".", O_SEARCH);
+ if (!GNULIB_FCNTL_SAFER)
+ cwd->desc = fd_safer (cwd->desc);
+ if (cwd->desc < 0)
{
-#ifdef HAVE_FCHDIR
- cwd->desc = open (".", O_RDONLY);
- 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
+ cwd->name = getcwd (NULL, 0);
+ return cwd->name ? 0 : -1;
}
- if (!have_working_fchdir)
- {
- cwd->name = xgetcwd ();
- if (cwd->name == NULL)
- {
- error (0, errno, "cannot get current directory");
- return 1;
- }
- }
+ set_cloexec_flag (cwd->desc, true);
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 (cwd, dest, from)
- 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_long (cwd->name);
}
void
-free_cwd (cwd)
- struct saved_cwd *cwd;
+free_cwd (struct saved_cwd *cwd)
{
if (cwd->desc >= 0)
close (cwd->desc);
- if (cwd->name)
- free (cwd->name);
+ free (cwd->name);
}
-
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