Make chdir-safer.c more efficient on a system with no symlinks.

* lib/chdir-safer.c (chdir_no_follow): Skip lstat and fstat calls
also if ELOOP is zero.  Suggested by Bruno Haible.

diff --git a/ChangeLog b/ChangeLog
index 67653c1192ad1e2c1f355e24b799fd76d3fdafb6..4f7483a0885c3d2e720b8adbda5e0a93a61d7158 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2008-05-10  Jim Meyering  <meyering@redhat.com>
 
+       Make chdir-safer.c more efficient on a system with no symlinks.
+       * lib/chdir-safer.c (chdir_no_follow): Skip lstat and fstat calls
+       also if ELOOP is zero.  Suggested by Bruno Haible.
+
        Make chdir-safer.c slightly safer.
        * lib/chdir-safer.c (chdir_no_follow): Test HAVE_WORKING_O_NOFOLLOW,
        not O_NOFOLLOW, in case the latter is nonzero and open ignores it.

diff --git a/lib/chdir-safer.c b/lib/chdir-safer.c
index a5c9a4d1214b9796d17abe3d4ee6f4f4e8cc9b38..03f372050f9decc43e326e406d7f9aa3af0b5821 100644 (file)
--- a/lib/chdir-safer.c
+++ b/lib/chdir-safer.c
@@ -50,8 +50,10 @@ chdir_no_follow (char const *dir)
   /* If open follows symlinks, lstat DIR and fstat FD to ensure that
      they are the same file; if they are different files, set errno to
      ELOOP (the same value that open uses for symlinks with
-     O_NOFOLLOW) so the caller can report a failure.  */
-  if (! HAVE_WORKING_O_NOFOLLOW)
+     O_NOFOLLOW) so the caller can report a failure.
+     Skip this check if ELOOP == 0, which should be the case
+     on any system that lacks symlink support.  */
+  if (ELOOP && ! HAVE_WORKING_O_NOFOLLOW)
     {
       struct stat sb1;
       result = lstat (dir, &sb1);