Work around an fchownat bug in glibc-2.4:

http://lists.ubuntu.com/archives/ubuntu-users/2006-September/093218.html
This bug would cause "chown -RP ... DIR" to follow symlinks in DIR,
in spite of the -P option.
* m4/openat.m4 (gl_FUNC_FCHOWNAT, gl_FUNC_FCHOWNAT_DEREF_BUG):
New macros.
(gl_PREREQ_OPENAT): Require gl_FUNC_FCHOWNAT.
* modules/openat (Files): Add lib/fchownat.c.
* lib/openat.c (fchownat): Don't define here.  Move to...
* lib/fchownat.c: ...this new file.

1 files changed, 49 insertions, 0 deletions

diff --git a/lib/fchownat.c b/lib/fchownat.c
new file mode 100644
index 0000000000..382ed7bc14
--- /dev/null
+++ b/lib/fchownat.c
@@ -0,0 +1,49 @@
+/* This function serves as replacement for a missing fchownat function,
+   as well as a work around for the fchownat bug in glibc-2.4:
+    <http://lists.ubuntu.com/archives/ubuntu-users/2006-September/093218.html>
+   when the buggy fchownat-with-AT_SYMLINK_NOFOLLOW operates on a symlink, it
+   mistakenly affects the symlink referent, rather than the symlink itself.
+
+   Copyright (C) 2006 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.
+
+   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.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+#include "openat.h"
+
+#include <unistd.h>
+
+#include "dirname.h" /* solely for definition of IS_ABSOLUTE_FILE_NAME */
+#include "save-cwd.h"
+#include "openat-priv.h"
+
+/* Replacement for Solaris' function by the same name.
+   Invoke chown or lchown on file, FILE, using OWNER and GROUP, in the
+   directory open on descriptor FD.  If FLAG is AT_SYMLINK_NOFOLLOW, then
+   use lchown, otherwise, use chown.  If possible, do it without changing
+   the working directory.  Otherwise, resort to using save_cwd/fchdir,
+   then mkdir/restore_cwd.  If either the save_cwd or the restore_cwd
+   fails, then give a diagnostic and exit nonzero.  */
+
+#define AT_FUNC_NAME fchownat
+#define AT_FUNC_F1 lchown
+#define AT_FUNC_F2 chown
+#define AT_FUNC_USE_F1_COND flag == AT_SYMLINK_NOFOLLOW
+#define AT_FUNC_POST_FILE_PARAM_DECLS , uid_t owner, gid_t group, int flag
+#define AT_FUNC_POST_FILE_ARGS        , owner, group
+#include "at-func.c"