diff --git a/src/fd/mod.rs b/src/fd/mod.rs
index f39af6da8b..bb54bdecc2 100644
--- a/src/fd/mod.rs
+++ b/src/fd/mod.rs
@@ -82,6 +82,10 @@ bitflags! {
 bitflags! {
 	#[derive(Debug, Copy, Clone)]
 	pub struct AccessPermission: u32 {
+		const S_IFMT = 0o170000;
+		const S_IFSOCK = 0140000;
+		const S_IFLNK = 0o120000;
+		const S_IFREG = 0o100000;
 		const S_IRUSR = 0o400;
 		const S_IWUSR = 0o200;
 		const S_IXUSR = 0o100;