Partially reverts patch
fc33350 from 2009-09-02.
* modules/chdir-long (Depends-on): Relax openat-safer to openat.
* modules/save-cwd (Depends-on): Replace fcntl-safer with
unistd-safer.
* lib/chdir-long.c (includes): Replace "fcntl--.h" with
<fcntl.h>; this module does not leak fds.
* lib/openat.c (includes): Do not use "fcntl_safer"; plain openat
must be allowed to return 0, leaving openat_safer to add the
safety.
(openat_permissive): Avoid writing to just-opened fd 2 if
restoring the current directory fails.
* lib/openat-die.c (openat_restore_fail): Add comment.
* lib/save-cwd.c (includes): Make "fcntl--.h" conditional.
(save_cwd): Guarantee safe fd, but without use of open_safer.
* tests/test-openat.c: New test.
* modules/openat-tests (Files, Makefile.am): Distribute and build
new file.
Signed-off-by: Eric Blake <ebb9@byu.net>
2009-09-19 Eric Blake <ebb9@byu.net>
+ openat: allow return of fd 0
+ * modules/chdir-long (Depends-on): Relax openat-safer to openat.
+ * modules/save-cwd (Depends-on): Replace fcntl-safer with
+ unistd-safer.
+ * lib/chdir-long.c (includes): Replace "fcntl--.h" with
+ <fcntl.h>; this module does not leak fds.
+ * lib/openat.c (includes): Do not use "fcntl_safer"; plain openat
+ must be allowed to return 0, leaving openat_safer to add the
+ safety.
+ (openat_permissive): Avoid writing to just-opened fd 2 if
+ restoring the current directory fails.
+ * lib/openat-die.c (openat_restore_fail): Add comment.
+ * lib/save-cwd.c (includes): Make "fcntl--.h" conditional.
+ (save_cwd): Guarantee safe fd, but without use of open_safer.
+ * tests/test-openat.c: New test.
+ * modules/openat-tests (Files, Makefile.am): Distribute and build
+ new file.
+
relocatable-prog-wrapper: fix build
* modules/relocatable-prog-wrapper (Files): Update name of
canonicalize m4 file, broken on 2009-09-17.
#include "chdir-long.h"
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
-#include <errno.h>
#include <stdio.h>
-#include <assert.h>
-
-#include "fcntl--.h"
#ifndef PATH_MAX
# error "compile this file only if your system defines PATH_MAX"
#endif
+/* The results of openat() in this file are not leaked to any
+ single-threaded code that could use stdio.
+ FIXME - if the kernel ever adds support for multi-thread safety for
+ avoiding standard fds, then we should use openat_safer. */
+
struct cd_buf
{
int fd;
abort ();
}
+
+/* Exit with an error about failure to restore the working directory
+ during an openat emulation. The caller must ensure that fd 2 is
+ not a just-opened fd, even when openat_safer is not in use. */
+
void
openat_restore_fail (int errnum)
{
#include "openat-priv.h"
#include "save-cwd.h"
-/* We can't use "fcntl--.h", so that openat_safer does not interfere. */
-#if GNULIB_FCNTL_SAFER
-# include "fcntl-safer.h"
-# undef open
-# define open open_safer
-#endif
-
/* Replacement for Solaris' openat function.
<http://www.google.com/search?q=openat+site:docs.sun.com>
First, try to simulate it via open ("/proc/self/fd/FD/FILE").
if (save_ok && restore_cwd (&saved_cwd) != 0)
{
if (! cwd_errno)
- openat_restore_fail (errno);
+ {
+ /* Don't write a message to just-created fd 2. */
+ saved_errno = errno;
+ if (err == STDERR_FILENO)
+ close (err);
+ openat_restore_fail (saved_errno);
+ }
*cwd_errno = errno;
}
}
/* save-cwd.c -- Save and restore current working directory.
- Copyright (C) 1995, 1997, 1998, 2003, 2004, 2005, 2006 Free
+ Copyright (C) 1995, 1997, 1998, 2003, 2004, 2005, 2006, 2009 Free
Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
#include "save-cwd.h"
#include <errno.h>
+#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
-#include <unistd.h>
#include "chdir-long.h"
-#include "fcntl--.h"
+#include "unistd--.h"
#include "xgetcwd.h"
+#if GNULIB_FCNTL_SAFER
+# include "fcntl--.h"
+#else
+# define GNULIB_FCNTL_SAFER 0
+#endif
+
/* On systems without the fchdir function (WOE), pretend that open
always returns -1 so that save_cwd resorts to using xgetcwd.
Since chdir_long requires fchdir, use chdir instead. */
cwd->name = NULL;
cwd->desc = open (".", O_RDONLY);
+ if (!GNULIB_FCNTL_SAFER)
+ cwd->desc = fd_safer (cwd->desc);
if (cwd->desc < 0)
{
cwd->name = xgetcwd ();
atexit
fchdir
fcntl-h
-openat-safer
+openat
memchr
mempcpy
memrchr
Files:
tests/test-rmdir.h
+tests/test-openat.c
tests/test-unlinkat.c
Depends-on:
AC_CHECK_FUNCS_ONCE([symlink])
Makefile.am:
-TESTS += test-unlinkat
-check_PROGRAMS += test-unlinkat
+TESTS += test-openat test-unlinkat
+check_PROGRAMS += test-openat test-unlinkat
+test_openat_LDADD = $(LDADD) @LIBINTL@
test_unlinkat_LDADD = $(LDADD) @LIBINTL@
Depends-on:
chdir-long
-fcntl-safer
-xgetcwd
stdbool
+unistd-safer
+xgetcwd
configure.ac:
gl_SAVE_CWD
--- /dev/null
+/* Test that openat works.
+ Copyright (C) 2009 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 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, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Eric Blake <ebb9@byu.net>, 2009. */
+
+#include <config.h>
+
+#include <fcntl.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define ASSERT(expr) \
+ do \
+ { \
+ if (!(expr)) \
+ { \
+ fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+ fflush (stderr); \
+ abort (); \
+ } \
+ } \
+ while (0)
+
+int
+main ()
+{
+ /* FIXME - add more tests. For example, share /dev/null and
+ trailing slash tests with test-open, and do more checks for
+ proper fd handling. */
+
+ /* Check that even when *-safer modules are in use, plain openat can
+ land in fd 0. Do this test last, since it is destructive to
+ stdin. */
+ ASSERT (close (STDIN_FILENO) == 0);
+ ASSERT (openat (AT_FDCWD, ".", O_RDONLY) == STDIN_FILENO);
+ {
+ int dfd = open (".", O_RDONLY);
+ ASSERT (STDIN_FILENO < dfd);
+ ASSERT (chdir ("..") == 0);
+ ASSERT (close (STDIN_FILENO) == 0);
+ ASSERT (openat (dfd, ".", O_RDONLY) == STDIN_FILENO);
+ ASSERT (close (dfd) == 0);
+ }
+ return 0;
+}
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