Gary V. Vaughan wrote:
>> ix86 SLED 10 gcc 4.1.2 (fchownat, rename, renameat)
I'm seeing this failure on a Linux/x86 machine (SUSE Linux Enterprise Server 10,
Linux 2.6.16.60, glibc 2.4):
test-chown.h:79: assertion failed
FAIL: test-fchownat
The call that fails is
ASSERT (func ("", -1, -1) == -1);
in other words
ASSERT (fchownat (3, "", -1, -1, 0) == -1);
The test is right, because POSIX:2008 says about chown, fchownat:
"These functions shall fail if:
[ENOENT]
A component of path does not name an existing file or path is an
empty string."
The function fchownat, on this platform, comes from glibc:
$ nm test-fchownat|grep chown
0804c320 t do_chown
0804c2e0 t do_lchown
U fchownat@@GLIBC_2.4
0804b370 t test_chown
08048e10 t test_lchown
and strace shows this system call:
chown32("/proc/self/fd/3/", -1, -1) = 0
So the bug is in glibc. It was fixed there on 2009-10-30, following the
report at <http://sources.redhat.com/bugzilla/show_bug.cgi?id=10609>.
This fixes it for me. Jim, is this OK to push?
2010-11-12 Bruno Haible <br...@clisp.org>
openat: Work around glibc bug with fchownat() and empty file names.
* m4/openat.m4 (gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG): New macro.
(gl_FUNC_FCHOWNAT): Invoke it.
* lib/fchownat.c (rpl_fchownat): Handle the empty file name specially.
* doc/posix-functions/fchownat.texi: Document the glibc bug.
Reported by Gary V. Vaughan <g...@gnu.org>.
--- doc/posix-functions/fchownat.texi.orig Sat Nov 13 13:49:35 2010
+++ doc/posix-functions/fchownat.texi Sat Nov 13 04:06:29 2010
@@ -17,6 +17,9 @@
@code{AT_SYMLINK_NOFOLLOW}:
Linux kernel 2.6.17.
@item
+This function does not fail for an empty filename on some platforms:
+Linux with glibc < 2.11.
+...@item
This function is missing on some platforms:
glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Cygwin 1.5.x, mingw, Interix 3.5, BeOS.
--- lib/fchownat.c.orig Sat Nov 13 13:49:35 2010
+++ lib/fchownat.c Sat Nov 13 03:24:19 2010
@@ -88,6 +88,13 @@
if (flag == AT_SYMLINK_NOFOLLOW)
return local_lchownat (fd, file, owner, group);
# endif
+# if FCHOWNAT_EMPTY_FILENAME_BUG
+ if (file[0] == '\0')
+ {
+ errno = ENOENT;
+ return -1;
+ }
+# endif
# if CHOWN_TRAILING_SLASH_BUG
{
size_t len = strlen (file);
--- m4/openat.m4.orig Sat Nov 13 13:49:35 2010
+++ m4/openat.m4 Sat Nov 13 04:27:16 2010
@@ -1,4 +1,4 @@
-# serial 30
+# serial 31
# See if we need to use our replacement for Solaris' openat et al functions.
dnl Copyright (C) 2004-2010 Free Software Foundation, Inc.
@@ -96,6 +99,38 @@
AS_IF([test $gl_cv_func_fchownat_nofollow_works = no], [$1], [$2])
])
+# gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG([ACTION-IF-BUGGY[, ACTION-IF-NOT_BUGGY]])
+AC_DEFUN([gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG],
+[
+ dnl Persuade glibc <unistd.h> to declare fchownat().
+ AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+ AC_CACHE_CHECK([whether fchownat works with an empty file name],
+ [gl_cv_func_fchownat_empty_filename_works],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <unistd.h>
+ #include <fcntl.h>
+ ]],
+ [[int fd;
+ int ret;
+ if (mkdir ("conftestdir", 0700) < 0)
+ return 2;
+ fd = open ("conftestdir", O_RDONLY);
+ if (fd < 0)
+ return 3;
+ ret = fchownat (fd, "", -1, -1, 0);
+ close (fd);
+ rmdir ("conftestdir");
+ return ret == 0;
+ ]])],
+ [gl_cv_func_fchownat_empty_filename_works=yes],
+ [gl_cv_func_fchownat_empty_filename_works=no],
+ [gl_cv_func_fchownat_empty_filename_works="guessing no"])
+ ])
+ AS_IF([test "$gl_cv_func_fchownat_empty_filename_works" != yes], [$1], [$2])
+])
+
# If we have the fchownat function, and it has the bug (in glibc-2.4)
# that it dereferences symlinks even with AT_SYMLINK_NOFOLLOW, then
# use the replacement function.
@@ -112,6 +148,12 @@
[Define to 1 if your platform has fchownat, but it cannot
perform lchown tasks.])
])
+ gl_FUNC_FCHOWNAT_EMPTY_FILENAME_BUG(
+ [REPLACE_FCHOWNAT=1
+ AC_DEFINE([FCHOWNAT_EMPTY_FILENAME_BUG], [1],
+ [Define to 1 if your platform has fchownat, but it does
+ not reject an empty file name.])
+ ])
if test $REPLACE_CHOWN = 1; then
REPLACE_FCHOWNAT=1
fi],
