Bump cAdvisor to v0.23.4

vendor/github.com/google/cadvisor/devicemapper/util.go

@@ -0,0 +1,60 @@
+// Copyright 2016 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 devicemapper
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// ThinLsBinaryPresent returns the location of the thin_ls binary in the mount
+// namespace cadvisor is running in or an error.  The locations checked are:
+//
+// - /bin/
+// - /usr/sbin/
+// - /usr/bin/
+//
+// ThinLsBinaryPresent checks these paths relative to:
+//
+// 1. For non-containerized operation - `/`
+// 2. For containerized operation - `/rootfs`
+//
+// The thin_ls binary is provided by the device-mapper-persistent-data
+// package.
+func ThinLsBinaryPresent() (string, error) {
+	var (
+		thinLsPath string
+		err        error
+	)
+
+	for _, path := range []string{"/bin", "/usr/sbin/", "/usr/bin"} {
+		// try paths for non-containerized operation
+		// note: thin_ls is most likely a symlink to pdata_tools
+		thinLsPath = filepath.Join(path, "thin_ls")
+		_, err = os.Stat(thinLsPath)
+		if err == nil {
+			return thinLsPath, nil
+		}
+
+		// try paths for containerized operation
+		thinLsPath = filepath.Join("/rootfs", thinLsPath)
+		_, err = os.Stat(thinLsPath)
+		if err == nil {
+			return thinLsPath, nil
+		}
+	}
+
+	return "", fmt.Errorf("unable to find thin_ls binary")
+}