/* provide consistent interface to chown for systems that don't interpret
an ID of -1 as meaning `don't change the corresponding ID'.
- Copyright (C) 1997 Free Software Foundation, Inc.
+ Copyright (C) 1997, 2004, 2005 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
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. */
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
/* written by Jim Meyering */
#include <sys/types.h>
#include <sys/stat.h>
-#ifdef HAVE_UNISTD_H
+#if HAVE_UNISTD_H
# include <unistd.h>
#endif
+#include <fcntl.h>
+#include <errno.h>
-/* FIXME: describe. */
+/* Provide a more-closely POSIX-conforming version of chown on
+ systems with one or both of the following problems:
+ - chown doesn't treat an ID of -1 as meaning
+ `don't change the corresponding ID'.
+ - chown doesn't dereference symlinks. */
int
-rpl_chown (file, uid, gid)
- const char *file;
- uid_t uid;
- gid_t gid;
+rpl_chown (const char *file, uid_t uid, gid_t gid)
{
+#if CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE
if (gid == (gid_t) -1 || uid == (uid_t) -1)
{
struct stat file_stats;
/* Stat file to get id(s) that should remain unchanged. */
if (stat (file, &file_stats))
- return 1;
+ return -1;
if (gid == (gid_t) -1)
gid = file_stats.st_gid;
if (uid == (uid_t) -1)
uid = file_stats.st_uid;
}
+#endif
+#if CHOWN_MODIFIES_SYMLINK
+ {
+ /* Handle the case in which the system-supplied chown function
+ does *not* follow symlinks. Instead, it changes permissions
+ on the symlink itself. To work around that, we open the
+ file (but this can fail due to lack of read or write permission) and
+ use fchown on the resulting descriptor. */
+ int fd = open (file, O_RDONLY | O_NONBLOCK | O_NOCTTY);
+ if (fd < 0
+ && (fd = open (file, O_WRONLY | O_NONBLOCK | O_NOCTTY)) < 0)
+ return -1;
+ if (fchown (fd, uid, gid))
+ {
+ int saved_errno = errno;
+ close (fd);
+ errno = saved_errno;
+ return -1;
+ }
+ return close (fd);
+ }
+#else
return chown (file, uid, gid);
+#endif
}