2 files changed, 21 insertions, 4 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index a2891fa9c91..5de5fefd6aa 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2011-07-18  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * fileio.c (Fcopy_file): Adjust mode if fchown fails.  (Bug#9002)
+        If fchown fails to set both uid and gid, try to set just gid,
+        as that is sometimes allowed.  Adjust the file's mode to eliminate
+        setuid or setgid bits that are inappropriate if fchown fails.
+
 2011-07-18  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * xdisp.c (next_element_from_string, next_element_from_buffer): Use EQ
diff --git a/src/fileio.c b/src/fileio.c
index a52e834c2b2..fb2c081ae5c 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -38,8 +38,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <selinux/context.h>
 #endif
 
-#include <ignore-value.h>
-
 #include "lisp.h"
 #include "intervals.h"
 #include "buffer.h"
@@ -1961,9 +1959,21 @@ on the system, we copy the SELinux context of FILE to NEWNAME.  */)
      owner and group.  */
   if (input_file_statable_p)
     {
+      int mode_mask = 07777;
       if (!NILP (preserve_uid_gid))
-        ignore_value (fchown (ofd, st.st_uid, st.st_gid));
-      if (fchmod (ofd, st.st_mode & 07777) != 0)
+        {
+          /* Attempt to change owner and group.  If that doesn't work
+             attempt to change just the group, as that is sometimes allowed.
+             Adjust the mode mask to eliminate setuid or setgid bits
+             that are inappropriate if the owner and group are wrong.  */
+          if (fchown (ofd, st.st_uid, st.st_gid) != 0)
+            {
+              mode_mask &= ~06000;
+              if (fchown (ofd, -1, st.st_gid) == 0)
+                mode_mask |= 02000;
+            }
+        }
+      if (fchmod (ofd, st.st_mode & mode_mask) != 0)
         report_file_error ("Doing chmod", Fcons (newname, Qnil));
     }
 #endif  /* not MSDOS */