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authorJim Meyering <jim@meyering.net>2004-05-01 14:36:29 +0000
committerJim Meyering <jim@meyering.net>2004-05-01 14:36:29 +0000
commit87cb7bca6498cda16166f6c93e5b4aeba5a7bb81 (patch)
tree1bc804e9b6bddfa55d8db9684ac07a53e7e6896a /lib
parent83db4e147a59e082edfc4f8a511b6b1304a90821 (diff)
downloadcoreutils-87cb7bca6498cda16166f6c93e5b4aeba5a7bb81.tar.xz
(rpl_chown) [CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE]:
Wrap old code with this conditional. [CHOWN_MODIFIES_SYMLINK]: Try to work around a chown function that does not dereference symlinks.
Diffstat (limited to 'lib')
-rw-r--r--lib/chown.c40
1 files changed, 38 insertions, 2 deletions
diff --git a/lib/chown.c b/lib/chown.c
index 452fdfcac..460e4f623 100644
--- a/lib/chown.c
+++ b/lib/chown.c
@@ -1,6 +1,6 @@
/* 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 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
@@ -30,12 +30,26 @@
#if HAVE_UNISTD_H
# include <unistd.h>
#endif
+#if HAVE_FCNTL_H
+# include <fcntl.h>
+#else
+# include <sys/file.h>
+#endif
+#include <errno.h>
+#ifndef errno
+extern int errno;
+#endif
-/* 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 (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;
@@ -50,6 +64,28 @@ rpl_chown (const char *file, uid_t uid, gid_t 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 permission) and
+ use fchown on the resulting descriptor. */
+ int fd = open (file, O_RDONLY | O_NONBLOCK | O_NOCTTY);
+ if (fd == -1)
+ 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
}