wayland-server: Remove error event posting from wl_resource_create

The wl_client_add/new_object() functions sends out an NO_MEMORY error if
the allocation fails.  This was convenient in a couple of places where
that was all the error handling that was needed.  Unfortunately that
looks like out-of-memory isn't handled at the call site and set a bad
precedent for not cleaning up properly or not handling at all.

As we're introducing wl_resource_create() as a replacement for those two
functions, let's remove the automatic error event posting and require
the caller to do that if necessary.

This commit also introduces a new helper, wl_client_post_no_memory() to
make it possible to send NO_MEMORY events from bind where we don't have
a wl_resource.

src/wayland-server.c

@@ -404,6 +404,13 @@ wl_client_get_object(struct wl_client *client, uint32_t id)
 	return wl_map_lookup(&client->objects, id);
 }
 
+WL_EXPORT void
+wl_client_post_no_memory(struct wl_client *client)
+{
+	wl_resource_post_error(client->display_resource,
+			       WL_DISPLAY_ERROR_NO_MEMORY, "no memory");
+}
+
 WL_EXPORT void
 wl_resource_post_no_memory(struct wl_resource *resource)
 {
@@ -599,6 +606,11 @@ display_sync(struct wl_client *client,
 	uint32_t serial;
 
 	callback = wl_resource_create(client, &wl_callback_interface, 1, id);
+	if (callback == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+
 	serial = wl_display_get_serial(client->display);
 	wl_callback_send_done(callback, serial);
 	wl_resource_destroy(callback);
@@ -621,6 +633,11 @@ display_get_registry(struct wl_client *client,
 
 	registry_resource =
 		wl_resource_create(client, &wl_registry_interface, 1, id);
+	if (registry_resource == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+
 	wl_resource_set_implementation(registry_resource,
 				       &registry_interface,
 				       display, unbind_resource);
@@ -655,6 +672,11 @@ bind_display(struct wl_client *client,
 
 	client->display_resource =
 		wl_resource_create(client, &wl_display_interface, 1, id);
+	if (client->display_resource == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+
 	wl_resource_set_implementation(client->display_resource,
 				       &display_interface, display,
 				       destroy_client_display_resource);
@@ -1007,10 +1029,8 @@ wl_resource_create(struct wl_client *client,
 	struct wl_resource *resource;
 
 	resource = malloc(sizeof *resource);
-	if (resource == NULL) {
-		wl_resource_post_no_memory(client->display_resource);
+	if (resource == NULL)
 		return NULL;
-	}
 
 	if (id == 0)
 		id = wl_map_insert_new(&client->objects, 0, NULL);
@@ -1087,7 +1107,11 @@ wl_client_add_object(struct wl_client *client,
 	struct wl_resource *resource;
 
 	resource = wl_resource_create(client, interface, -1, id);
-	wl_resource_set_implementation(resource, implementation, data, NULL);
+	if (resource == NULL)
+		wl_client_post_no_memory(client);
+	else
+		wl_resource_set_implementation(resource,
+					       implementation, data, NULL);
 
 	return resource;
 }
@@ -1105,7 +1129,11 @@ wl_client_new_object(struct wl_client *client,
 	struct wl_resource *resource;
 
 	resource = wl_resource_create(client, interface, -1, 0);
-	wl_resource_set_implementation(resource, implementation, data, NULL);
+	if (resource == NULL)
+		wl_client_post_no_memory(client);
+	else
+		wl_resource_set_implementation(resource,
+					       implementation, data, NULL);
 
 	return resource;
 }

src/wayland-server.h

@@ -128,6 +128,8 @@ struct wl_listener *wl_client_get_destroy_listener(struct wl_client *client,
 
 struct wl_resource *
 wl_client_get_object(struct wl_client *client, uint32_t id);
+void
+wl_client_post_no_memory(struct wl_client *client);
 
 struct wl_listener {
 	struct wl_list link;

src/wayland-shm.c

@@ -115,7 +115,7 @@ shm_pool_create_buffer(struct wl_client *client, struct wl_resource *resource,
 
 	buffer = malloc(sizeof *buffer);
 	if (buffer == NULL) {
-		wl_resource_post_no_memory(resource);
+		wl_client_post_no_memory(client);
 		return;
 	}
 
@@ -129,6 +129,13 @@ shm_pool_create_buffer(struct wl_client *client, struct wl_resource *resource,
 
 	buffer->resource =
 		wl_resource_create(client, &wl_buffer_interface, 1, id);
+	if (buffer->resource == NULL) {
+		wl_client_post_no_memory(client);
+		shm_pool_unref(pool);
+		free(buffer);
+		return;
+	}
+
 	wl_resource_set_implementation(buffer->resource,
 				       &shm_buffer_interface,
 				       buffer, destroy_buffer);
@@ -182,7 +189,7 @@ shm_create_pool(struct wl_client *client, struct wl_resource *resource,
 
 	pool = malloc(sizeof *pool);
 	if (pool == NULL) {
-		wl_resource_post_no_memory(resource);
+		wl_client_post_no_memory(client);
 		goto err_close;
 	}
 
@@ -207,8 +214,12 @@ shm_create_pool(struct wl_client *client, struct wl_resource *resource,
 
 	pool->resource =
 		wl_resource_create(client, &wl_shm_pool_interface, 1, id);
-	if (!pool->resource)
-		goto err_free;
+	if (!pool->resource) {
+		wl_client_post_no_memory(client);
+		munmap(pool->data, pool->size);
+		free(pool);
+		return;
+	}
 
 	wl_resource_set_implementation(pool->resource,
 				       &shm_pool_interface,
@@ -233,6 +244,11 @@ bind_shm(struct wl_client *client,
 	struct wl_resource *resource;
 
 	resource = wl_resource_create(client, &wl_shm_interface, 1, id);
+	if (!resource) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+
 	wl_resource_set_implementation(resource, &shm_interface, data, NULL);
 
 	wl_shm_send_format(resource, WL_SHM_FORMAT_ARGB8888);
@@ -276,6 +292,11 @@ wl_shm_buffer_create(struct wl_client *client,
 
 	buffer->resource =
 		wl_resource_create(client, &wl_buffer_interface, 1, id);
+	if (buffer->resource == NULL) {
+		free(buffer);
+		return NULL;
+	}
+
 	wl_resource_set_implementation(buffer->resource,
 				       &shm_buffer_interface,
 				       buffer, destroy_buffer);