1 files changed, 80 insertions, 0 deletions
diff --git a/vendor/k8s.io/kubernetes/pkg/util/io/writer.go b/vendor/k8s.io/kubernetes/pkg/util/io/writer.go
new file mode 100644
index 000000000..086508c90
--- /dev/null
+++ b/vendor/k8s.io/kubernetes/pkg/util/io/writer.go
@@ -0,0 +1,80 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+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 io
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+
+	"github.com/golang/glog"
+)
+
+// Writer is an interface which allows to write data to a file.
+type Writer interface {
+	WriteFile(filename string, data []byte, perm os.FileMode) error
+}
+
+// StdWriter implements Writer interface and uses standard libraries
+// for writing data to files.
+type StdWriter struct {
+}
+
+func (writer *StdWriter) WriteFile(filename string, data []byte, perm os.FileMode) error {
+	return ioutil.WriteFile(filename, data, perm)
+}
+
+// Alternative implementation of Writer interface that allows writing data to file
+// using nsenter command.
+// If a program (e.g. kubelet) runs in a container it may want to write data to
+// a mounted device. Since in Docker, mount propagation mode is set to private,
+// it will not see the mounted device in its own namespace. To work around this
+// limitaion one has to first enter hosts namespace (by using 'nsenter') and only
+// then write data.
+type NsenterWriter struct {
+}
+
+// TODO: should take a writer, not []byte
+func (writer *NsenterWriter) WriteFile(filename string, data []byte, perm os.FileMode) error {
+	cmd := "nsenter"
+	base_args := []string{
+		"--mount=/rootfs/proc/1/ns/mnt",
+		"--",
+	}
+
+	echo_args := append(base_args, "sh", "-c", fmt.Sprintf("cat > %s", filename))
+	glog.V(5).Infof("Command to write data to file: %v %v", cmd, echo_args)
+	command := exec.Command(cmd, echo_args...)
+	command.Stdin = bytes.NewBuffer(data)
+	outputBytes, err := command.CombinedOutput()
+	if err != nil {
+		glog.Errorf("Output from writing to %q: %v", filename, string(outputBytes))
+		return err
+	}
+
+	chmod_args := append(base_args, "chmod", fmt.Sprintf("%o", perm), filename)
+	glog.V(5).Infof("Command to change permissions to file: %v %v", cmd, chmod_args)
+	outputBytes, err = exec.Command(cmd, chmod_args...).CombinedOutput()
+	if err != nil {
+		glog.Errorf("Output from chmod command: %v", string(outputBytes))
+		return err
+	}
+
+	return nil
+}