diff --git a/tools/updater.cpp b/tools/updater.cpp
index b7ea191..6fed1d6 100644
--- a/tools/updater.cpp
+++ b/tools/updater.cpp
@@ -23,6 +23,9 @@
 #include <cstring>
 #include <memory>
 
+namespace host_tool
+{
+
 void updaterMain(BlobInterface* blob, DataInterface* handler,
                  const std::string& imagePath, const std::string& signaturePath)
 {
@@ -95,3 +98,5 @@
 
     return;
 }
+
+} // namespace host_tool