Compile nsinit into docker for use with dockerinit

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

docker/docker.go

@@ -17,7 +17,7 @@ import (
 )
 
 func main() {
-	if selfPath := utils.SelfPath(); selfPath == "/sbin/init" || selfPath == "/.dockerinit" {
+	if selfPath := utils.SelfPath(); selfPath == "/sbin/init" || strings.Contains(selfPath, "/.dockerinit") {
 		// Running in init mode
 		sysinit.SysInit()
 		return

execdriver/driver.go

@@ -51,6 +51,8 @@ type InitArgs struct {
 	Args       []string
 	Mtu        int
 	Driver     string
+	Console    string
+	Pipe       int
 }
 
 // Driver specific information based on

execdriver/namespaces/driver.go

@@ -28,6 +28,28 @@ var (
 
 func init() {
 	execdriver.RegisterInitFunc(DriverName, func(args *execdriver.InitArgs) error {
+		var container *libcontainer.Container
+		f, err := os.Open("container.json")
+		if err != nil {
+			return err
+		}
+		if err := json.NewDecoder(f).Decode(&container); err != nil {
+			f.Close()
+			return err
+		}
+		f.Close()
+
+		cwd, err := os.Getwd()
+		if err != nil {
+			return err
+		}
+		syncPipe, err := nsinit.NewSyncPipeFromFd(0, uintptr(args.Pipe))
+		if err != nil {
+			return err
+		}
+		if err := nsinit.Init(container, cwd, args.Console, syncPipe, args.Args); err != nil {
+			return err
+		}
 		return nil
 	})
 }
@@ -115,14 +137,15 @@ type dockerCommandFactory struct {
 func (d *dockerCommandFactory) Create(container *libcontainer.Container,
 	console, logFile string, syncFd uintptr, args []string) *exec.Cmd {
 	c := d.c
-	aname, _ := exec.LookPath("nsinit")
-	c.Path = aname
+	// we need to join the rootfs because nsinit will setup the rootfs and chroot
+	initPath := filepath.Join(c.Rootfs, c.InitPath)
+
+	c.Path = initPath
 	c.Args = append([]string{
-		aname,
+		initPath,
+		"-driver", DriverName,
 		"-console", console,
 		"-pipe", fmt.Sprint(syncFd),
-		"-log", logFile,
-		"init",
 	}, args...)
 	c.SysProcAttr = &syscall.SysProcAttr{
 		Cloneflags: uintptr(nsinit.GetNamespaceFlags(container.Namespaces)),

sysinit/sysinit.go

@@ -53,6 +53,8 @@ func SysInit() {
 		privileged = flag.Bool("privileged", false, "privileged mode")
 		mtu        = flag.Int("mtu", 1500, "interface mtu")
 		driver     = flag.String("driver", "", "exec driver")
+		pipe       = flag.Int("pipe", 0, "sync pipe fd")
+		console    = flag.String("console", "", "console (pty slave) path")
 	)
 	flag.Parse()
 
@@ -79,6 +81,8 @@ func SysInit() {
 		Args:       flag.Args(),
 		Mtu:        *mtu,
 		Driver:     *driver,
+		Console:    *console,
+		Pipe:       *pipe,
 	}
 
 	if err := executeProgram(args); err != nil {