1 files changed, 19 insertions, 21 deletions

diff --git a/vendor/k8s.io/kubernetes/pkg/util/io/writer.go b/vendor/k8s.io/kubernetes/pkg/util/io/writer.go
index 086508c90..8d1d9964e 100644
--- a/vendor/k8s.io/kubernetes/pkg/util/io/writer.go
+++ b/vendor/k8s.io/kubernetes/pkg/util/io/writer.go
@@ -21,13 +21,15 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
-	"os/exec"
+
+	"k8s.io/kubernetes/pkg/util/nsenter"
 
 	"github.com/golang/glog"
 )
 
 // Writer is an interface which allows to write data to a file.
 type Writer interface {
+	// WriteFile mimics ioutil.WriteFile.
 	WriteFile(filename string, data []byte, perm os.FileMode) error
 }
 
@@ -36,41 +38,37 @@ type Writer interface {
 type StdWriter struct {
 }
 
+// WriteFile directly calls ioutil.WriteFile.
 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.
+// NsenterWriter is 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 {
-}
+// limitation 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
+// WriteFile calls 'nsenter cat - > <the file>' and 'nsenter chmod' to create a
+// file on the host.
 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)
+	ne := nsenter.NewNsenter()
+	echoArgs := []string{"-c", fmt.Sprintf("cat > %s", filename)}
+	glog.V(5).Infof("nsenter: write data to file %s by nsenter", filename)
+	command := ne.Exec("sh", echoArgs)
+	command.SetStdin(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()
+	chmodArgs := []string{fmt.Sprintf("%o", perm), filename}
+	glog.V(5).Infof("nsenter: change permissions of file %s to %s", filename, chmodArgs[0])
+	outputBytes, err = ne.Exec("chmod", chmodArgs).CombinedOutput()
 	if err != nil {
 		glog.Errorf("Output from chmod command: %v", string(outputBytes))
 		return err