diff --git a/src/factory/WFNameService.cc b/src/factory/WFNameService.cc
index e37c1ffc..786b240b 100644
--- a/src/factory/WFNameService.cc
+++ b/src/factory/WFNameService.cc
@@ -1,3 +1,21 @@
+/*
+  Copyright (c) 2020 Sogou, Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+  Author: Xie Han (xiehan@sogou-inc.com)
+*/
+
 #include <errno.h>
 #include <stddef.h>
 #include <string.h>