+#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 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 result = fchown (fd, uid, gid);
+ int saved_errno = errno;
+
+ /* POSIX says fchown can fail with errno == EINVAL on sockets,
+ so fall back on chown in that case. */
+ struct stat sb;
+ bool fchown_socket_failure =
+ (result != 0 && saved_errno == EINVAL
+ && fstat (fd, &sb) == 0 && S_ISFIFO (sb.st_mode));
+
+ close (fd);
+
+ if (! fchown_socket_failure)
+ {
+ errno = saved_errno;
+ return result;
+ }
+ }
+ else if (errno != EACCES)
+ return -1;
+ }
+#endif