Add EmptyPath for FchownatFlags

src/unistd.rs

@@ -627,12 +627,20 @@ pub fn chown<P: ?Sized + NixPath>(path: &P, owner: Option<Uid>, group: Option<Gi
 }
 
 /// Flags for `fchownat` function.
+#[cfg(not(target_os = "linux"))]
 #[derive(Clone, Copy, Debug)]
 pub enum FchownatFlags {
     FollowSymlink,
     NoFollowSymlink,
 }
 
+#[cfg(target_os = "linux")]
+pub enum FchownatFlags {
+    FollowSymlink,
+    NoFollowSymlink,
+    EmptyPath,
+}
+
 /// Change the ownership of the file at `path` to be owned by the specified
 /// `owner` (user) and `group`.
 ///
@@ -662,9 +670,17 @@ pub fn fchownat<P: ?Sized + NixPath>(
     flag: FchownatFlags,
 ) -> Result<()> {
     let atflag =
-        match flag {
-            FchownatFlags::FollowSymlink => AtFlags::empty(),
-            FchownatFlags::NoFollowSymlink => AtFlags::AT_SYMLINK_NOFOLLOW,
+        if cfg!(target_os = "linux") {
+            match flag {
+                FchownatFlags::FollowSymlink => AtFlags::empty(),
+                FchownatFlags::NoFollowSymlink => AtFlags::AT_SYMLINK_NOFOLLOW,
+                _ => AtFlags::AT_EMPTY_PATH,
+            }
+        } else {
+            match flag {
+                FchownatFlags::FollowSymlink => AtFlags::empty(),
+                _ => AtFlags::AT_SYMLINK_NOFOLLOW,
+            }
         };
     let res = path.with_nix_path(|cstr| unsafe {
         let (uid, gid) = chown_raw_ids(owner, group);