@@ -5,17 +5,12 @@ type Container struct {

 	ReadonlyFs   bool         `json:"readonly_fs,omitempty"`

 	User         string       `json:"user,omitempty"`

 	WorkingDir   string       `json:"working_dir,omitempty"`

-	Command      *Command     `json:"command,omitempty"`

+	Env          []string     `json:"environment,omitempty"`

 	Namespaces   Namespaces   `json:"namespaces,omitempty"`

 	Capabilities Capabilities `json:"capabilities,omitempty"`

 	Network      *Network     `json:"network,omitempty"`

 }

-type Command struct {

-	Args []string `json:"args,omitempty"`

-	Env  []string `json:"environment,omitempty"`

-}

-

 type Network struct {

 	IP      string `json:"ip,omitempty"`

 	Gateway string `json:"gateway,omitempty"`

@@ -1,16 +1,11 @@

 {

     "hostname": "koye",

-    "command": {

-        "args": [

-            "/bin/bash"

-        ],

-        "environment": [

-            "HOME=/",

-            "PATH=PATH=$PATH:/bin:/usr/bin:/sbin:/usr/sbin",

-            "container=docker",

-            "TERM=xterm-256color"

-        ]

-    },

+    "environment": [

+        "HOME=/",

+        "PATH=PATH=$PATH:/bin:/usr/bin:/sbin:/usr/sbin",

+        "container=docker",

+        "TERM=xterm-256color"

+    ],

     "namespaces": [

         "NEWIPC",

         "NEWNS",

@@ -16,17 +16,13 @@ import (

 	"syscall"

 )

-func execCommand(container *libcontainer.Container) (int, error) {

+func execCommand(container *libcontainer.Container, args []string) (int, error) {

 	master, console, err := createMasterAndConsole()

 	if err != nil {

 		return -1, err

 	}

-	command := exec.Command("nsinit", "init", console)

-	command.SysProcAttr = &syscall.SysProcAttr{

-		Cloneflags: uintptr(getNamespaceFlags(container.Namespaces) | syscall.CLONE_VFORK), // we need CLONE_VFORK so we can wait on the child

-	}

-

+	command := createCommand(container, console, args)

 	// create a pipe so that we can syncronize with the namespaced process and

 	// pass the veth name to the child

 	inPipe, err := command.StdinPipe()

@@ -39,6 +35,7 @@ func execCommand(container *libcontainer.Container) (int, error) {

 	if err := writePidFile(command); err != nil {

 		return -1, err

 	}

+	defer deletePidFile()

 	if container.Network != nil {

 		vethPair, err := setupVeth(container.Network.Bridge, command.Process.Pid)

@@ -134,3 +131,15 @@ func createVethPair() (name1 string, name2 string, err error) {

 func writePidFile(command *exec.Cmd) error {

 	return ioutil.WriteFile(".nspid", []byte(fmt.Sprint(command.Process.Pid)), 0655)

 }

+

+func deletePidFile() error {

+	return os.Remove(".nspid")

+}

+

+func createCommand(container *libcontainer.Container, console string, args []string) *exec.Cmd {

+	command := exec.Command("nsinit", append([]string{"init", console}, args...)...)

+	command.SysProcAttr = &syscall.SysProcAttr{

+		Cloneflags: uintptr(getNamespaceFlags(container.Namespaces) | syscall.CLONE_VFORK), // we need CLONE_VFORK so we can wait on the child

+	}

+	return command

+}

@@ -5,19 +5,13 @@ import (

 	"github.com/dotcloud/docker/pkg/libcontainer"

 	"github.com/dotcloud/docker/pkg/libcontainer/capabilities"

 	"github.com/dotcloud/docker/pkg/system"

-	"io/ioutil"

 	"os"

 	"path/filepath"

 	"strconv"

 	"syscall"

 )

-func execinCommand(container *libcontainer.Container) (int, error) {

-	nspid, err := readPid()

-	if err != nil {

-		return -1, err

-	}

-

+func execinCommand(container *libcontainer.Container, nspid int, args []string) (int, error) {

 	for _, ns := range container.Namespaces {

 		if err := system.Unshare(namespaceMap[ns]); err != nil {

 			return -1, err

@@ -67,7 +61,7 @@ func execinCommand(container *libcontainer.Container) (int, error) {

 			if err := capabilities.DropCapabilities(container); err != nil {

 				return -1, fmt.Errorf("drop capabilities %s", err)

 			}

-			if err := system.Exec(container.Command.Args[0], container.Command.Args[0:], container.Command.Env); err != nil {

+			if err := system.Exec(args[0], args[0:], container.Env); err != nil {

 				return -1, err

 			}

 		}

@@ -84,24 +78,12 @@ func execinCommand(container *libcontainer.Container) (int, error) {

 	if err := capabilities.DropCapabilities(container); err != nil {

 		return -1, fmt.Errorf("drop capabilities %s", err)

 	}

-	if err := system.Exec(container.Command.Args[0], container.Command.Args[0:], container.Command.Env); err != nil {

+	if err := system.Exec(args[0], args[0:], container.Env); err != nil {

 		return -1, err

 	}

 	panic("unreachable")

 }

-func readPid() (int, error) {

-	data, err := ioutil.ReadFile(".nspid")

-	if err != nil {

-		return -1, err

-	}

-	pid, err := strconv.Atoi(string(data))

-	if err != nil {

-		return -1, err

-	}

-	return pid, nil

-}

-

 func getNsFds(pid int, container *libcontainer.Container) ([]uintptr, error) {

 	fds := make([]uintptr, len(container.Namespaces))

 	for i, ns := range container.Namespaces {

@@ -14,7 +14,7 @@ import (

 	"syscall"

 )

-func initCommand(container *libcontainer.Container, console string) error {

+func initCommand(container *libcontainer.Container, console string, args []string) error {

 	rootfs, err := resolveRootfs()

 	if err != nil {

 		return err

@@ -72,7 +72,7 @@ func initCommand(container *libcontainer.Container, console string) error {

 			return fmt.Errorf("chdir to %s %s", container.WorkingDir, err)

 		}

 	}

-	if err := system.Exec(container.Command.Args[0], container.Command.Args[0:], container.Command.Env); err != nil {

+	if err := system.Exec(args[0], args[0:], container.Env); err != nil {

 		return fmt.Errorf("exec %s", err)

 	}

 	panic("unreachable")

@@ -4,8 +4,10 @@ import (

 	"encoding/json"

 	"errors"

 	"github.com/dotcloud/docker/pkg/libcontainer"

+	"io/ioutil"

 	"log"

 	"os"

+	"strconv"

 )

 var (

@@ -25,24 +27,29 @@ func main() {

 	}

 	switch os.Args[1] {

 	case "exec":

-		exitCode, err := execCommand(container)

+		var exitCode int

+		nspid, err := readPid()

+		if err != nil {

+			if !os.IsNotExist(err) {

+				log.Fatal(err)

+			}

+		}

+		if nspid > 0 {

+			exitCode, err = execinCommand(container, nspid, os.Args[2:])

+		} else {

+			exitCode, err = execCommand(container, os.Args[2:])

+		}

 		if err != nil {

 			log.Fatal(err)

 		}

 		os.Exit(exitCode)

 	case "init":

-		if argc != 3 {

+		if argc < 3 {

 			log.Fatal(ErrWrongArguments)

 		}

-		if err := initCommand(container, os.Args[2]); err != nil {

+		if err := initCommand(container, os.Args[2], os.Args[3:]); err != nil {

 			log.Fatal(err)

 		}

-	case "execin":

-		exitCode, err := execinCommand(container)

-		if err != nil {

-			log.Fatal(err)

-		}

-		os.Exit(exitCode)

 	default:

 		log.Fatalf("command not supported for nsinit %s", os.Args[1])

 	}

@@ -61,3 +68,15 @@ func loadContainer() (*libcontainer.Container, error) {

 	}

 	return container, nil

 }

+

+func readPid() (int, error) {

+	data, err := ioutil.ReadFile(".nspid")

+	if err != nil {

+		return -1, err

+	}

+	pid, err := strconv.Atoi(string(data))

+	if err != nil {

+		return -1, err

+	}

+	return pid, nil

+}