diff --git a/tools/atree/fs.cpp b/tools/atree/fs.cpp
index 15d6092..a233832 100644
--- a/tools/atree/fs.cpp
+++ b/tools/atree/fs.cpp
@@ -9,6 +9,7 @@
 #include <errno.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <string.h>
 #include <host/CopyFile.h>
 
 using namespace std;