Use nsinit for setting up namespace

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

pkg/libcontainer/cli/main.go

@@ -32,6 +32,7 @@ func init() {
 func nsinitFunc(container *libcontainer.Container) error {
 	container.Master = uintptr(masterFd)
 	container.Console = console
+	container.LogFile = "/root/logs"
 
 	return nsinit.InitNamespace(container)
 }

pkg/libcontainer/container.go

@@ -13,6 +13,7 @@ type Container struct {
 	Capabilities Capabilities `json:"capabilities,omitempty"`
 	Master       uintptr      `json:"master"`
 	Console      string       `json:"console"`
+	LogFile      string       `json:"log_file"`
 }
 
 type Command struct {

pkg/libcontainer/namespaces/exec.go

@@ -44,9 +44,10 @@ func ExecContainer(container *libcontainer.Container) (pid int, err error) {
 	// we need CLONE_VFORK so we can wait on the child
 	flag := uintptr(getNamespaceFlags(container.Namespaces) | CLONE_VFORK)
 
-	command := exec.Command(nsinit, "init", "-master", strconv.Itoa(int(master.Fd())), "-console", console)
+	command := exec.Command(nsinit, "-master", strconv.Itoa(int(master.Fd())), "-console", console, "init")
 	command.SysProcAttr = &syscall.SysProcAttr{}
 	command.SysProcAttr.Cloneflags = flag
+	command.ExtraFiles = []*os.File{master}
 	//	command.SysProcAttr.Setctty = true
 
 	if err := command.Start(); err != nil {
@@ -64,7 +65,6 @@ func ExecContainer(container *libcontainer.Container) (pid int, err error) {
 			log.Println(err)
 		}
 	}()
-	command.Wait()
 	return pid, nil
 }
 

pkg/libcontainer/namespaces/nsinit/init.go

@@ -14,6 +14,10 @@ import (
 // InitNamespace should be run inside an existing namespace to setup
 // common mounts, drop capabilities, and setup network interfaces
 func InitNamespace(container *libcontainer.Container) error {
+	if err := setLogFile(container); err != nil {
+		return err
+	}
+
 	rootfs, err := resolveRootfs(container)
 	if err != nil {
 		return err
@@ -138,3 +142,12 @@ func openTerminal(name string, flag int) (*os.File, error) {
 	}
 	return os.NewFile(uintptr(r), name), nil
 }
+
+func setLogFile(container *libcontainer.Container) error {
+	f, err := os.OpenFile(container.LogFile, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0655)
+	if err != nil {
+		return err
+	}
+	log.SetOutput(f)
+	return nil
+}