X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fsave-cwd.c;h=9ae37b08d30ae9f406269e9673ba4c7ba3d3b120;hb=fdd1b511c5c12912aae79b58e0c5f6ffa0492d6e;hp=c18d08841a77cc16e8d7d0254f5f064bbd3c30ff;hpb=68af56be3e061b97cf97150094bc50b0aa364cbb;p=gnulib.git

diff --git a/lib/save-cwd.c b/lib/save-cwd.c
index c18d08841..9ae37b08d 100644
--- a/lib/save-cwd.c
+++ b/lib/save-cwd.c
@@ -1,10 +1,12 @@
 /* save-cwd.c -- Save and restore current working directory.
-   Copyright (C) 1995, 1997, 1998, 2003 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
@@ -12,135 +14,80 @@
    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.  */
+   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.  */
 
-#if 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>
 
-#if HAVE_UNISTD_H
-# include <unistd.h>
-#endif
+#include "chdir-long.h"
+#include "unistd--.h"
+#include "cloexec.h"
 
-#if 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
 
-#ifndef O_DIRECTORY
-# define O_DIRECTORY 0
-#endif
-
-#include "save-cwd.h"
-#include "error.h"
-
-char *xgetcwd (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 (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)
     {
-#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
+      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 (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
@@ -148,6 +95,5 @@ free_cwd (struct saved_cwd *cwd)
 {
   if (cwd->desc >= 0)
     close (cwd->desc);
-  if (cwd->name)
-    free (cwd->name);
+  free (cwd->name);
 }