protoize

[gnulib.git] / lib / rename.c

diff --git a/lib/rename.c b/lib/rename.c
index a40bbb5..d649e2e 100644 (file)
--- a/lib/rename.c
+++ b/lib/rename.c
@@ -1,4 +1,4 @@
-/* rename.c -- BSD compatible directory function for System V
+/* BSD compatible rename and directory rename function for System V.
    Copyright (C) 1988, 1990 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
@@ -12,36 +12,64 @@
    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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <errno.h>
-#ifndef STDC_HEADERS
+#ifndef errno
 extern int errno;
 #endif
 
+#if STAT_MACROS_BROKEN
+# undef S_ISDIR
+#endif
+
 #if !defined(S_ISDIR) && defined(S_IFDIR)
-#define        S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
+# define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
 #endif
 
 /* Rename file FROM to file TO.
    Return 0 if successful, -1 if not. */
 
 int
-rename (from, to)
-     char *from;
-     char *to;
+rename (char *from, char *to)
 {
-  struct stat from_stats;
+  struct stat from_stats, to_stats;
   int pid, status;
 
   if (stat (from, &from_stats))
     return -1;
 
-  if (unlink (to) && errno != ENOENT)
-    return -1;
+  /* Be careful not to unlink `from' if it happens to be equal to `to' or
+     (on filesystems that silently truncate filenames after 14 characters)
+     if `from' and `to' share the significant characters. */
+  if (stat (to, &to_stats))
+    {
+      if (errno != ENOENT)
+        return -1;
+    }
+  else
+    {
+      if ((from_stats.st_dev == to_stats.st_dev)
+          && (from_stats.st_ino == to_stats.st_ino))
+        /* `from' and `to' designate the same file on that filesystem. */
+        return 0;
+
+      if (unlink (to) && errno != ENOENT)
+        return -1;
+    }
+
+#ifdef MVDIR
+
+/* If MVDIR is defined, it should be the full filename of a setuid root
+   program able to link and unlink directories.  If MVDIR is not defined,
+   then the capability of renaming directories may be missing.  */
 
   if (S_ISDIR (from_stats.st_mode))
     {
@@ -66,6 +94,9 @@ rename (from, to)
        }
     }
   else
+
+#endif /* MVDIR */
+
     {
       if (link (from, to))
        return -1;