From 2ae6f54200bad1f3609ba25b61917c56066e4dc3 Mon Sep 17 00:00:00 2001
From: Rob Norris <rw_norris@hotmail.com>
Date: Sun, 20 Jul 2014 10:27:24 +0100
Subject: [PATCH] Prevention of crashing in mapcache when tmp variable is NULL.

I haven't been able to trace why/when tmp becomes NULL,
 but at least one user has encountered this condition.
Thus add protection against deferencing a NULL pointer.
---
 src/mapcache.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/mapcache.c b/src/mapcache.c
index 5417ae1a..16422abe 100644
--- a/src/mapcache.c
+++ b/src/mapcache.c
@@ -182,6 +182,7 @@ void a_mapcache_remove_all_shrinkfactors ( gint x, gint y, gint z, guint16 type,
   /* TODO: check logic here */
   do {
     tmp = loop->next;
+    if ( tmp ) {
     if ( strncmp(tmp->key, key, len) == 0 )
     {
       cache_remove(tmp->key);
@@ -198,7 +199,8 @@ void a_mapcache_remove_all_shrinkfactors ( gint x, gint y, gint z, guint16 type,
     }
     else
       loop = tmp;
-
+    } else
+      loop = NULL;
   } while ( loop && (loop != queue_tail || tmp == NULL) );
 
   /* loop thru list, looking for the one, compare first whatever chars */
-- 
2.39.5