Set rootcontext of emptyDir tmpfs mounts correctly

pkg/kubelet/root_context_linux.go

@@ -0,0 +1,47 @@
+// +build linux
+
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubelet
+
+import (
+	"github.com/docker/libcontainer/selinux"
+)
+
+// getRootContext gets the SELinux context of the kubelet rootDir
+// or returns an error.
+func (kl *Kubelet) getRootDirContext() (string, error) {
+	// If SELinux is not enabled, return an empty string
+	if !selinux.SelinuxEnabled() {
+		return "", nil
+	}
+
+	// Get the SELinux context of the rootDir.
+	rootContext, err := selinux.Getfilecon(kl.getRootDir())
+	if err != nil {
+		return "", err
+	}
+
+	// There is a libcontainer bug where the null byte is not stripped from
+	// the result of reading some selinux xattrs; strip it.
+	//
+	// TODO: remove when https://github.com/docker/libcontainer/issues/499
+	// is fixed
+	rootContext = rootContext[:len(rootContext)-1]
+
+	return rootContext, nil
+}