dnsproxy: Check that cache is valid before accessing it.

The cache can become invalid by just disconnecting a service.
In that case we must not access the cache hash.

diff --git a/src/dnsproxy.c b/src/dnsproxy.c
index 6f8d39a..dc44a46 100644 (file)
--- a/src/dnsproxy.c
+++ b/src/dnsproxy.c
@@ -1130,9 +1130,12 @@ static gboolean cache_invalidate_entry(gpointer key, gpointer value,
  */
 static void cache_invalidate(void)
 {
-       DBG("Invalidating the DNS cache");
-        g_hash_table_foreach_remove(cache, cache_invalidate_entry,
-                                               NULL);
+       DBG("Invalidating the DNS cache %p", cache);
+
+       if (cache == NULL)
+               return;
+
+       g_hash_table_foreach_remove(cache, cache_invalidate_entry, NULL);
 }
 
 static void cache_refresh_entry(struct cache_entry *entry)
@@ -1175,6 +1178,9 @@ static void cache_refresh_iterator(gpointer key, gpointer value,
 
 static void cache_refresh(void)
 {
+       if (cache == NULL)
+               return;
+
        g_hash_table_foreach(cache, cache_refresh_iterator, NULL);
 }
 
@@ -1650,8 +1656,10 @@ static void destroy_server(struct server_data *server)
        }
        g_free(server->interface);
 
-       if (__sync_fetch_and_sub(&cache_refcount, 1) == 1)
+       if (__sync_fetch_and_sub(&cache_refcount, 1) == 1) {
                g_hash_table_destroy(cache);
+               cache = NULL;
+       }
 
        g_free(server);
 }