/* 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, 2004, 2005 Free Software Foundation, Inc.
+ an ID of -1 as meaning "don't change the corresponding ID".
- This program is free software; you can redistribute it and/or modify
+ Copyright (C) 1997, 2004-2007, 2009-2014 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.
+ 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
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* written by Jim Meyering */
#include <config.h>
-/* Disable the definition of chown to rpl_chown (from config.h) in this
- file. Otherwise, we'd get conflicting prototypes for rpl_chown on
- most systems. */
-#undef chown
+/* Specification. */
+#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#if HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-#if HAVE_FCNTL_H
-# include <fcntl.h>
-#else
-# include <sys/file.h>
-#endif
#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#if !HAVE_CHOWN
+
+/* Simple stub that always fails with ENOSYS, for mingw. */
+int
+chown (const char *file _GL_UNUSED, uid_t uid _GL_UNUSED,
+ gid_t gid _GL_UNUSED)
+{
+ errno = ENOSYS;
+ return -1;
+}
+
+#else /* HAVE_CHOWN */
+
+/* Below we refer to the system's chown(). */
+# undef chown
+
+/* The results of open() in this file are not used with fchdir,
+ therefore save some unnecessary work in fchdir.c. */
+# undef open
+# undef close
/* 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'.
+ "don't change the corresponding ID".
- chown doesn't dereference symlinks. */
int
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 st;
+ bool stat_valid = false;
+ int result;
+
+# if CHOWN_CHANGE_TIME_BUG
+ if (gid != (gid_t) -1 || uid != (uid_t) -1)
{
- struct stat file_stats;
+ if (stat (file, &st))
+ return -1;
+ stat_valid = true;
+ }
+# endif
+# if CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE
+ if (gid == (gid_t) -1 || uid == (uid_t) -1)
+ {
/* Stat file to get id(s) that should remain unchanged. */
- if (stat (file, &file_stats))
- return -1;
-
+ if (!stat_valid && stat (file, &st))
+ return -1;
if (gid == (gid_t) -1)
- gid = file_stats.st_gid;
-
+ gid = st.st_gid;
if (uid == (uid_t) -1)
- uid = file_stats.st_uid;
+ uid = st.st_uid;
}
-#endif
+# endif
-#if CHOWN_MODIFIES_SYMLINK
+# 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 open_flags = O_NONBLOCK | O_NOCTTY;
+ int fd = open (file, O_RDONLY | open_flags);
+ if (0 <= fd
+ || (errno == EACCES
+ && 0 <= (fd = open (file, O_WRONLY | open_flags))))
{
- int saved_errno = errno;
- close (fd);
- errno = saved_errno;
- return -1;
+ int saved_errno;
+ bool fchown_socket_failure;
+
+ result = fchown (fd, uid, gid);
+ saved_errno = errno;
+
+ /* POSIX says fchown can fail with errno == EINVAL on sockets
+ and pipes, so fall back on chown in that case. */
+ fchown_socket_failure =
+ (result != 0 && saved_errno == EINVAL
+ && fstat (fd, &st) == 0
+ && (S_ISFIFO (st.st_mode) || S_ISSOCK (st.st_mode)));
+
+ close (fd);
+
+ if (! fchown_socket_failure)
+ {
+ errno = saved_errno;
+ return result;
+ }
}
- return close (fd);
+ else if (errno != EACCES)
+ return -1;
}
-#else
- return chown (file, uid, gid);
-#endif
+# endif
+
+# if CHOWN_TRAILING_SLASH_BUG
+ if (!stat_valid)
+ {
+ size_t len = strlen (file);
+ if (len && file[len - 1] == '/' && stat (file, &st))
+ return -1;
+ }
+# endif
+
+ result = chown (file, uid, gid);
+
+# if CHOWN_CHANGE_TIME_BUG
+ if (result == 0 && stat_valid
+ && (uid == st.st_uid || uid == (uid_t) -1)
+ && (gid == st.st_gid || gid == (gid_t) -1))
+ {
+ /* No change in ownership, but at least one argument was not -1,
+ so we are required to update ctime. Since chown succeeded,
+ we assume that chmod will do likewise. Fortunately, on all
+ known systems where a 'no-op' chown skips the ctime update, a
+ 'no-op' chmod still does the trick. */
+ result = chmod (file, st.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO
+ | S_ISUID | S_ISGID | S_ISVTX));
+ }
+# endif
+
+ return result;
}
+
+#endif /* HAVE_CHOWN */
projects / gnulib.git / blobdiff