X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fgetcwd.c;h=2397c08c839e82e781c5837df6baa48a97dbf1a6;hb=679b14d8851a364efdffbdf50d4aa43921762076;hp=978c5383737da0672fa98a1c71a7f2b377360095;hpb=1e4ece4ab9850fbfa88c9ec43ea518c7bc266792;p=gnulib.git

diff --git a/lib/getcwd.c b/lib/getcwd.c
index 978c53837..2397c08c8 100644
--- a/lib/getcwd.c
+++ b/lib/getcwd.c
@@ -2,23 +2,23 @@
    Foundation, Inc.
    This file is part of the GNU C Library.
 
-   This program is free software; you can redistribute it and/or modify
+   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
    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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #if !_LIBC
 # include <config.h>
-# include "getcwd.h"
+# include <unistd.h>
+# include "dirfd.h"
 #endif
 
 #include <errno.h>
@@ -29,6 +29,14 @@
 
 #include <fcntl.h> /* For AT_FDCWD on Solaris 9.  */
 
+/* If this host provides the openat function, then enable
+   code below to make getcwd more efficient and robust.  */
+#ifdef HAVE_OPENAT
+# define HAVE_OPENAT_SUPPORT 1
+#else
+# define HAVE_OPENAT_SUPPORT 0
+#endif
+
 #ifndef __set_errno
 # define __set_errno(val) (errno = (val))
 #endif
@@ -89,7 +97,7 @@
 #endif
 
 #if !_LIBC
-# define __getcwd getcwd
+# define __getcwd rpl_getcwd
 # define __lstat lstat
 # define __closedir closedir
 # define __opendir opendir
@@ -122,7 +130,7 @@ __getcwd (char *buf, size_t size)
       DEEP_NESTING = 100
     };
 
-#ifdef AT_FDCWD
+#if HAVE_OPENAT_SUPPORT
   int fd = AT_FDCWD;
   bool fd_needs_closing = false;
 #else
@@ -140,13 +148,18 @@ __getcwd (char *buf, size_t size)
   size_t allocated = size;
   size_t used;
 
-#if HAVE_PARTLY_WORKING_GETCWD && !defined AT_FDCWD
+#if HAVE_PARTLY_WORKING_GETCWD
   /* The system getcwd works, except it sometimes fails when it
      shouldn't, setting errno to ERANGE, ENAMETOOLONG, or ENOENT.  If
      AT_FDCWD is not defined, the algorithm below is O(N**2) and this
      is much slower than the system getcwd (at least on GNU/Linux).
      So trust the system getcwd's results unless they look
-     suspicious.  */
+     suspicious.
+
+     Use the system getcwd even if we have openat support, since the
+     system getcwd works even when a parent is unreadable, while the
+     openat-based approach does not.  */
+
 # undef getcwd
   dir = getcwd (buf, size);
   if (dir || (errno != ERANGE && !is_ENAMETOOLONG (errno) && errno != ENOENT))
@@ -198,7 +211,7 @@ __getcwd (char *buf, size_t size)
       bool use_d_ino = true;
 
       /* Look at the parent directory.  */
-#ifdef AT_FDCWD
+#if HAVE_OPENAT_SUPPORT
       fd = openat (fd, "..", O_RDONLY);
       if (fd < 0)
 	goto lose;
@@ -225,10 +238,12 @@ __getcwd (char *buf, size_t size)
       mount_point = dotdev != thisdev;
 
       /* Search for the last directory.  */
-#ifdef AT_FDCWD
+#if HAVE_OPENAT_SUPPORT
       dirstream = fdopendir (fd);
       if (dirstream == NULL)
 	goto lose;
+      /* Reset fd.  It may have been closed by fdopendir.  */
+      fd = dirfd (dirstream);
       fd_needs_closing = false;
 #else
       dirstream = __opendir (dotlist);
@@ -279,7 +294,7 @@ __getcwd (char *buf, size_t size)
 
 	  {
 	    int entry_status;
-#ifdef AT_FDCWD
+#if HAVE_OPENAT_SUPPORT
 	    entry_status = fstatat (fd, d->d_name, &st, AT_SYMLINK_NOFOLLOW);
 #else
 	    /* Compute size needed for this file name, or for the file
@@ -375,7 +390,7 @@ __getcwd (char *buf, size_t size)
   if (dirp == &dir[allocated - 1])
     *--dirp = '/';
 
-#ifndef AT_FDCWD
+#if ! HAVE_OPENAT_SUPPORT
   if (dotlist != dots)
     free (dotlist);
 #endif
@@ -383,7 +398,7 @@ __getcwd (char *buf, size_t size)
   used = dir + allocated - dirp;
   memmove (dir, dirp, used);
 
-  if (buf == NULL && size == 0)
+  if (size == 0)
     /* Ensure that the buffer is only as large as necessary.  */
     buf = realloc (dir, used);
 
@@ -401,7 +416,7 @@ __getcwd (char *buf, size_t size)
     int save = errno;
     if (dirstream)
       __closedir (dirstream);
-#ifdef AT_FDCWD
+#if HAVE_OPENAT_SUPPORT
     if (fd_needs_closing)
       close (fd);
 #else