coredumps are not nice.

deal with the fact that when we are merging the lists in host_list both can
be NULL.
found at EuroBSDCon 2002 while I was explaining the expansion process to
Paul de Weerd

ok dhartmei@

1 files changed, 10 insertions, 4 deletions

diff --git a/sbin/pfctl/parse.y b/sbin/pfctl/parse.y
index f1c353a6959..af86299f944 100644
--- a/sbin/pfctl/parse.y
+++ b/sbin/pfctl/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.227 2002/11/29 15:37:23 henning Exp $	*/
+/*	$OpenBSD: parse.y,v 1.228 2002/11/29 17:14:18 henning Exp $	*/
 
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
@@ -1021,9 +1021,15 @@ ipspec		: ANY				{ $$ = NULL; }
 host_list	: xhost				{ $$ = $1; }
 		| host_list comma xhost		{
 			/* $3 may be a list, so use its tail pointer */
-			$1->tail->next = $3->tail;
-			$1->tail = $3->tail;
-			$$ = $1;
+			if ($3 == NULL)
+				$$ = $1;
+			else if ($1 == NULL)
+				$$ = $3;
+			else {
+				$1->tail->next = $3->tail;
+				$1->tail = $3->tail;
+				$$ = $1;
+			}
 		}
 		;