(copy_internal): Be consistent with intra-device behavior

and *do* allow `mv' to move a file onto a symlink to itself when that
symlink is on a separate partition.  With fileutils-4.0j, it would
fail with a diagnostic saying they were the same file.
Reported by Bruno Haible.

1 files changed, 31 insertions, 12 deletions

diff --git a/src/copy.c b/src/copy.c
index 9d8c0c070..fda7eaf50 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -371,6 +371,7 @@ copy_internal (const char *src_path, const char *dst_path,
   char *earlier_file;
   char *dst_backup = NULL;
   int fix_mode = 0;
+  int force = x->force;
 
   if (move_mode && rename_succeeded)
     *rename_succeeded = 0;
@@ -426,14 +427,7 @@ copy_internal (const char *src_path, const char *dst_path,
 	  if (!same
 
 	      /* If we'll remove DST_PATH first, then this doesn't matter.  */
-	      && ! x->force
-
-	      /* Allow them to be the same (and don't set `same') if
-		 we're in move mode and the target is a symlink
-		 on the same partition.  */
-	      && !(move_mode
-		   && S_ISLNK (dst_sb.st_mode)
-		   && src_sb.st_dev == dst_sb.st_dev)
+	      && ! force
 
 	      /* If we're making a backup, we'll detect the problem case in
 		 copy_reg because SRC_PATH will no longer exist.  Allowing
@@ -453,7 +447,32 @@ copy_internal (const char *src_path, const char *dst_path,
 		  && stat (src_path, &src2_sb) == 0
 		  && SAME_INODE (src2_sb, dst2_sb))
 		{
-		  same = 1;
+		  /* Be careful in move mode when the target is a symlink
+		     to the source.    */
+		  if (move_mode
+		      && S_ISLNK (dst_sb.st_mode))
+		    {
+		      if (src_sb.st_dev != dst_sb.st_dev)
+			{
+			  /* This happens when the target is a symlink that
+			     resides on a file system different from the one
+			     on which the source resides.  Tell the copying
+			     code (below) that it must unlink the destination
+			     before opening it.  Otherwise, we'd end up
+			     destroying SRC when opening it via the symlink.  */
+			  force = 1;
+			}
+		      else
+			{
+			  /* Don't set `same'.
+			     Since they're on the same partition, rename
+			     will end up removing the destination symlink.  */
+			}
+		    }
+		  else
+		    {
+		      same = 1;
+		    }
 		}
 	    }
 #endif
@@ -464,7 +483,7 @@ copy_internal (const char *src_path, const char *dst_path,
 		return 0;
 
 	      if (x->backup_type == none
-		  && (!x->force || same_name (src_path, dst_path)))
+		  && (!force || same_name (src_path, dst_path)))
 		{
 		  error (0, 0, _("`%s' and `%s' are the same file"),
 			 src_path, dst_path);
@@ -486,7 +505,7 @@ copy_internal (const char *src_path, const char *dst_path,
 		return 0;
 	    }
 
-	  if (!S_ISDIR (src_type) && !x->force && x->interactive)
+	  if (!S_ISDIR (src_type) && !force && x->interactive)
 	    {
 	      if (euidaccess (dst_path, W_OK) != 0)
 		{
@@ -554,7 +573,7 @@ copy_internal (const char *src_path, const char *dst_path,
 		}
 	      new_dst = 1;
 	    }
-	  else if (x->force)
+	  else if (force)
 	    {
 	      if (S_ISDIR (dst_sb.st_mode))
 		{