AutoUnionFs: allow reads of status/gounionfs_version.

unionfs/autounion.go

@@ -245,6 +245,7 @@ func (me *AutoUnionFs) GetAttr(path string) (*os.FileInfo, fuse.Status) {
 	if path == filepath.Join(_STATUS, _VERSION) {
 		a := &os.FileInfo{
 			Mode: fuse.S_IFREG | 0644,
+			Size: int64(len(fuse.Version())),
 		}
 		return a, fuse.OK
 	}
@@ -295,6 +296,16 @@ func (me *AutoUnionFs) StatusDir() (stream chan fuse.DirEntry, status fuse.Statu
 	return stream, fuse.OK
 }
 
+func (me *AutoUnionFs) Open(path string, flags uint32) (fuse.File, fuse.Status) {
+	if path == _STATUS + "/" + _VERSION {
+		if flags & fuse.O_ANYWRITE != 0 {
+			return nil, fuse.EPERM
+		}
+		return fuse.NewReadOnlyFile([]byte(fuse.Version())), fuse.OK
+	}
+	return nil, fuse.ENOENT
+}
+
 func (me *AutoUnionFs) OpenDir(name string) (stream chan fuse.DirEntry, status fuse.Status) {
 	switch name {
 	case _STATUS:

unionfs/autounion_test.go

@@ -55,6 +55,18 @@ func setup(t *testing.T) (workdir string, cleanup func()) {
 	}
 }
 
+func TestVersion(t *testing.T) {
+	wd, clean := setup(t)
+	defer clean()
+
+	c, err := ioutil.ReadFile(wd+"/mount/status/gounionfs_version")
+	CheckSuccess(err)
+	if len(c) == 0 {
+		t.Fatal("No version found.")
+	}
+	log.Println("Found version:", string(c))
+}
+
 func TestAutoFsSymlink(t *testing.T) {
 	wd, clean := setup(t)
 	defer clean()