Diagnose unsupported uses of `backname' helper function.

* automake.in (backname): Error out if the path points outside
the directory it started in.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/automake.in b/automake.in
index 4e5348478..335fe130a 100755
--- a/automake.in
+++ b/automake.in
@@ -1053,7 +1053,8 @@ sub backname ($)
 	next if $_ eq '.' || $_ eq '';
 	if ($_ eq '..')
 	{
-	    pop @res;
+	    pop @res
+	      or prog_error ("trying to reverse path `$file' pointing outside tree");
 	}
 	else
 	{