Strip leading forward slash from resource

api.go

@@ -878,23 +878,24 @@ func postContainersCopy(srv *Server, version float64, w http.ResponseWriter, r *
 	name := vars["name"]
 
 	copyData := &APICopy{}
-	if r.Header.Get("Content-Type") == "application/json" {
+	contentType := r.Header.Get("Content-Type")
+	if contentType == "application/json" {
 		if err := json.NewDecoder(r.Body).Decode(copyData); err != nil {
 			return err
 		}
 	} else {
-		return fmt.Errorf("Content-Type not supported: %s", r.Header.Get("Content-Type"))
+		return fmt.Errorf("Content-Type not supported: %s", contentType)
 	}
 
 	if copyData.Resource == "" {
 		return fmt.Errorf("Resource cannot be empty")
 	}
 	if copyData.Resource[0] == '/' {
-		return fmt.Errorf("Resource cannot contain a leading /")
+		copyData.Resource = copyData.Resource[1:]
 	}
 
 	if err := srv.ContainerCopy(name, copyData.Resource, w); err != nil {
-		utils.Debugf("%s", err)
+		utils.Debugf("%s", err.Error())
 		return err
 	}
 	return nil

api_test.go

@@ -1181,7 +1181,7 @@ func TestPostContainersCopy(t *testing.T) {
 	}
 
 	r := httptest.NewRecorder()
-	copyData := APICopy{HostPath: ".", Resource: "test.txt"}
+	copyData := APICopy{HostPath: ".", Resource: "/test.txt"}
 
 	jsonData, err := json.Marshal(copyData)
 	if err != nil {

commands.go

@@ -1492,8 +1492,8 @@ func (cli *DockerCli) CmdCp(args ...string) error {
 		return err
 	}
 
-	r := bytes.NewReader(data)
 	if statusCode == 200 {
+		r := bytes.NewReader(data)
 		if err := Untar(r, copyData.HostPath); err != nil {
 			return err
 		}

container.go

@@ -1094,5 +1094,19 @@ func (container *Container) Copy(resource string) (Archive, error) {
 	if err := container.EnsureMounted(); err != nil {
 		return nil, err
 	}
-	return TarFilter(container.RootfsPath(), Uncompressed, []string{resource})
+	var filter []string
+	basePath := path.Join(container.RootfsPath(), resource)
+	stat, err := os.Stat(basePath)
+	if err != nil {
+		return nil, err
+	}
+	if !stat.IsDir() {
+		d, f := path.Split(basePath)
+		basePath = d
+		filter = []string{f}
+	} else {
+		filter = []string{path.Base(basePath)}
+		basePath = path.Dir(basePath)
+	}
+	return TarFilter(basePath, Uncompressed, filter)
 }