X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fchown.c;h=3582b04d67d720930cebb3cc35d598e94bdbc2d0;hb=3d986f521cac261e29c043be50bb626f7641d841;hp=d761c73399ec2a9c7f9787c7a17915d07e4ea870;hpb=a62be9f4039b4499cfbb76e394cad2259d03fa84;p=gnulib.git

diff --git a/lib/chown.c b/lib/chown.c
index d761c7339..3582b04d6 100644
--- a/lib/chown.c
+++ b/lib/chown.c
@@ -1,11 +1,12 @@
 /* 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 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   Copyright (C) 1997, 2004, 2005, 2006, 2007 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
@@ -13,30 +14,29 @@
    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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 <stdbool.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 <fcntl.h>
 #include <errno.h>
 
+/* 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
@@ -53,7 +53,7 @@ rpl_chown (const char *file, uid_t uid, gid_t gid)
 
       /* 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;
@@ -68,21 +68,36 @@ rpl_chown (const char *file, uid_t uid, gid_t gid)
     /* 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
+       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 == -1)
-      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 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);
-	errno = saved_errno;
-	return -1;
+
+	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
+
+  return chown (file, uid, gid);
 }