diff --git a/cmds/idmap2/include/idmap2/FileUtils.h b/cmds/idmap2/include/idmap2/FileUtils.h
index 2588688de44c4..bc0bb47fc2b71 100644
--- a/cmds/idmap2/include/idmap2/FileUtils.h
+++ b/cmds/idmap2/include/idmap2/FileUtils.h
@@ -17,6 +17,8 @@
 #ifndef IDMAP2_INCLUDE_IDMAP2_FILEUTILS_H_
 #define IDMAP2_INCLUDE_IDMAP2_FILEUTILS_H_
 
+#include <sys/types.h>
+
 #include <random>
 #include <string>