GNU file utilities

[gnulib.git] / lib / rename.c

diff --git a/lib/rename.c b/lib/rename.c
index a40bbb5..1502436 100644 (file)
--- a/lib/rename.c
+++ b/lib/rename.c
@@ -15,6 +15,17 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
+#ifdef HAVE_CONFIG_H
+#if defined (CONFIG_BROKETS)
+/* We use <config.h> instead of "config.h" so that a compilation
+   using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
+   (which it would do because it found this file in $srcdir).  */
+#include <config.h>
+#else
+#include "config.h"
+#endif
+#endif
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <errno.h>
@@ -22,8 +33,14 @@
 extern int errno;
 #endif
 
+#ifdef STAT_MACROS_BROKEN
+#ifdef S_ISDIR
+#undef S_ISDIR
+#endif
+#endif /* STAT_MACROS_BROKEN.  */
+
 #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.
@@ -34,14 +51,30 @@ rename (from, to)
      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_dev))
+        /* `from' and `to' designate the same file on that filesystem. */
+        return 0;
+
+      if (unlink (to) && errno != ENOENT)
+        return -1;
+    }
 
   if (S_ISDIR (from_stats.st_mode))
     {