libnm-glib: fix a crash when using multiple NMClients

NMObjectCache was assuming there would never be more than one object
with the same path, but since NMClient is an NMObject, it was getting
cached too, so if you created two clients and then unreffed one of
them, it's possible the wrong one could get left in the cache, causing
a crash the next time the other one called nm_object_cache_clear().

Fix this by only adding NMObjects to the cache in the codepaths where
we also check to see if the object was already in the cache.

(This also means we can remove the "except" argument to
nm_object_cache_clear(), since the NMClient won't be cached any more.)

libnm-glib/nm-client.c

@@ -1383,7 +1383,7 @@ proxy_name_owner_changed (DBusGProxy *proxy,
 		/* Clear object cache to ensure bad refcounting by clients doesn't
 		 * keep objects in the cache.
 		 */
-		_nm_object_cache_clear (NM_OBJECT (client));
+		_nm_object_cache_clear ();
 	} else {
 		_nm_object_suppress_property_updates (NM_OBJECT (client), FALSE);
 		_nm_object_reload_properties_async (NM_OBJECT (client), updated_properties, client);

libnm-glib/nm-object-cache.c

@@ -63,26 +63,26 @@ _nm_object_cache_get (const char *path)
 }
 
 void
-_nm_object_cache_clear (NMObject *except)
+_nm_object_cache_clear (void)
 {
 	GHashTableIter iter;
-	NMObject *obj;
+	GObject *obj;
 	const char *path;
 	char *foo;
 
-	_init_cache ();
+	if (!cache)
+		return;
+
 	g_hash_table_iter_init (&iter, cache);
 	while (g_hash_table_iter_next (&iter, (gpointer) &path, (gpointer) &obj)) {
-		if (obj != except) {
 		/* Remove the callback so that if the object isn't yet released
 		 * by a client, when it does finally get unrefed, it won't trigger
 		 * the cache removal for a new object with the same path as the
 		 * one being released.
 		 */
-			foo = g_object_steal_data (G_OBJECT (obj), "nm-object-cache-tag");
+		foo = g_object_steal_data (obj, "nm-object-cache-tag");
 		g_free (foo);
 
 		g_hash_table_iter_remove (&iter);
 	}
 }
-}

libnm-glib/nm-object-cache.h

@@ -30,7 +30,7 @@ G_BEGIN_DECLS
 /* Returns referenced object from the cache */
 NMObject *_nm_object_cache_get (const char *path);
 void _nm_object_cache_add (NMObject *object);
-void _nm_object_cache_clear (NMObject *except);
+void _nm_object_cache_clear (void);
 
 G_END_DECLS
 

libnm-glib/nm-object.c

@@ -159,8 +159,6 @@ constructor (GType type,
 		return NULL;
 	}
 
-	_nm_object_cache_add (NM_OBJECT (object));
-
 	return object;
 }
 
@@ -573,6 +571,8 @@ _nm_object_create (GType type, DBusGConnection *connection, const char *path)
 	                       NM_OBJECT_DBUS_CONNECTION, connection,
 	                       NM_OBJECT_DBUS_PATH, path,
 	                       NULL);
+	if (NM_IS_OBJECT (object))
+		_nm_object_cache_add (NM_OBJECT (object));
 	if (!g_initable_init (G_INITABLE (object), NULL, &error)) {
 		dbgmsg ("Could not create object for %s: %s", path, error->message);
 		g_error_free (error);
@@ -656,6 +656,8 @@ async_got_type (GType type, gpointer user_data)
 	                       NM_OBJECT_DBUS_PATH, async_data->path,
 	                       NULL);
 	g_warn_if_fail (object != NULL);
+	if (NM_IS_OBJECT (object))
+		_nm_object_cache_add (NM_OBJECT (object));
 	g_async_initable_init_async (G_ASYNC_INITABLE (object), G_PRIORITY_DEFAULT,
 	                             NULL, async_inited, async_data);
 }