Make native driver use Exec func with different CreateCommand

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

libcontainer/nsinit/create.go

@@ -0,0 +1,10 @@
+package nsinit
+
+import (
+	"os"
+	"os/exec"
+
+	"github.com/dotcloud/docker/pkg/libcontainer"
+)
+
+type CreateCommand func(container *libcontainer.Container, console, rootfs, dataPath, init string, childPipe *os.File, args []string) *exec.Cmd

libcontainer/nsinit/exec.go

@@ -17,7 +17,7 @@ import (
 
 // Exec performes setup outside of a namespace so that a container can be
 // executed.  Exec is a high level function for working with container namespaces.
-func Exec(container *libcontainer.Container, term Terminal, rootfs, dataPath string, args []string, startCallback func()) (int, error) {
+func Exec(container *libcontainer.Container, term Terminal, rootfs, dataPath string, args []string, createCommand CreateCommand, startCallback func()) (int, error) {
 	var (
 		master  *os.File
 		console string
@@ -39,7 +39,7 @@ func Exec(container *libcontainer.Container, term Terminal, rootfs, dataPath str
 		term.SetMaster(master)
 	}
 
-	command := CreateCommand(container, console, rootfs, dataPath, os.Args[0], syncPipe.child, args)
+	command := createCommand(container, console, rootfs, dataPath, os.Args[0], syncPipe.child, args)
 	if err := term.Attach(command); err != nil {
 		return -1, err
 	}
@@ -90,7 +90,7 @@ func Exec(container *libcontainer.Container, term Terminal, rootfs, dataPath str
 	return command.ProcessState.Sys().(syscall.WaitStatus).ExitStatus(), nil
 }
 
-// CreateCommand will return an exec.Cmd with the Cloneflags set to the proper namespaces
+// DefaultCreateCommand will return an exec.Cmd with the Cloneflags set to the proper namespaces
 // defined on the container's configuration and use the current binary as the init with the
 // args provided
 //
@@ -99,7 +99,7 @@ func Exec(container *libcontainer.Container, term Terminal, rootfs, dataPath str
 // root: the path to the container json file and information
 // pipe: sync pipe to syncronize the parent and child processes
 // args: the arguemnts to pass to the container to run as the user's program
-func CreateCommand(container *libcontainer.Container, console, rootfs, dataPath, init string, pipe *os.File, args []string) *exec.Cmd {
+func DefaultCreateCommand(container *libcontainer.Container, console, rootfs, dataPath, init string, pipe *os.File, args []string) *exec.Cmd {
 	// get our binary name from arg0 so we can always reexec ourself
 	env := []string{
 		"console=" + console,

libcontainer/nsinit/nsinit/main.go

@@ -39,7 +39,7 @@ func main() {
 			exitCode, err = nsinit.ExecIn(container, nspid, os.Args[2:])
 		} else {
 			term := nsinit.NewTerminal(os.Stdin, os.Stdout, os.Stderr, container.Tty)
-			exitCode, err = nsinit.Exec(container, term, "", dataPath, os.Args[2:], nil)
+			exitCode, err = nsinit.Exec(container, term, "", dataPath, os.Args[2:], nsinit.DefaultCreateCommand, nil)
 		}
 
 		if err != nil {

libcontainer/nsinit/unsupported.go

@@ -7,6 +7,10 @@ import (
 	"github.com/dotcloud/docker/pkg/libcontainer"
 )
 
+func Exec(container *libcontainer.Container, term Terminal, rootfs, dataPath string, args []string, createCommand CreateCommand, startCallback func()) (int, error) {
+	return -1, libcontainer.ErrUnsupported
+}
+
 func Init(container *libcontainer.Container, uncleanRootfs, consolePath string, syncPipe *SyncPipe, args []string) error {
 	return libcontainer.ErrUnsupported
 }