Implement Chmod in UnionFs.

unionfs/unionfs.go

@@ -254,6 +254,31 @@ func (me *UnionFs) Symlink(pointedTo string, linkName string) (code fuse.Status)
 	return code
 }
 
+func (me *UnionFs) Chmod(name string, mode uint32) (code fuse.Status) {
+	r := me.branchCache.Get(name).(getBranchResult)
+	if r.attr == nil || r.code != fuse.OK {
+		return r.code
+	}
+
+	if r.attr.Mode & fuse.S_IFREG == 0 {
+		return fuse.EPERM
+	}
+
+	permMask := uint32(07777)
+	oldMode := r.attr.Mode & permMask
+
+	if oldMode != mode {
+		if r.branch > 0 {
+			err := me.Promote(name, me.branches[r.branch])
+			if err != nil {
+				panic("copy: " + err.String())
+			}
+		}
+		me.fileSystems[0].Chmod(name, mode)
+	}
+	return fuse.OK
+}
+
 func (me *UnionFs) Access(name string, mode uint32) (code fuse.Status) {
 	i := me.getBranch(name)
 	if i >= 0 {

unionfs/unionfs_test.go

@@ -145,6 +145,27 @@ func TestSymlink(t *testing.T) {
 	}
 }
 
+func TestChmod(t *testing.T) {
+	wd, state := setup(t)
+	defer state.Unmount()
+
+	ro_fn := wd+"/ro/file"
+	m_fn := wd+"/mount/file"
+	writeToFile(ro_fn, "a", true)
+	err := os.Chmod(m_fn, 07070)
+	CheckSuccess(err)
+
+	fi, err := os.Lstat(m_fn)
+	CheckSuccess(err)
+	if fi.Mode & 07777 != 07070 {
+		t.Errorf("Unexpected mode found: %v", fi.Mode)
+	}
+	_, err = os.Lstat(wd+"/rw/file")
+	if err != nil {
+		t.Errorf("File not promoted")
+	}
+}
+
 func TestBasic(t *testing.T) {
 	wd, state := setup(t)
 	defer state.Unmount()