Add chroot driver for testing

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

container.go

@@ -690,6 +690,7 @@ func (container *Container) Start() (err error) {
 		Tty:         container.Config.Tty,
 		User:        container.Config.User,
 		WaitLock:    make(chan struct{}),
+		SysInitPath: runtime.sysInitPath,
 	}
 	container.process.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
 

execdriver/chroot/driver.go

@@ -0,0 +1,66 @@
+package chroot
+
+import (
+	"fmt"
+	"github.com/dotcloud/docker/execdriver"
+	"io/ioutil"
+	"os/exec"
+	"path"
+	"time"
+)
+
+type driver struct {
+}
+
+func NewDriver() (execdriver.Driver, error) {
+	return &driver{}, nil
+}
+
+func (d *driver) Start(c *execdriver.Process) error {
+	data, _ := ioutil.ReadFile(c.SysInitPath)
+	ioutil.WriteFile(path.Join(c.Rootfs, ".dockerinit"), data, 0644)
+	params := []string{
+		"chroot",
+		c.Rootfs,
+		"/.dockerinit",
+	}
+	// need to mount proc
+	params = append(params, c.Entrypoint)
+	params = append(params, c.Arguments...)
+
+	var (
+		name = params[0]
+		arg  = params[1:]
+	)
+	aname, err := exec.LookPath(name)
+	if err != nil {
+		aname = name
+	}
+	c.Path = aname
+	c.Args = append([]string{name}, arg...)
+
+	if err := c.Start(); err != nil {
+		return err
+	}
+
+	go func() {
+		if err := c.Wait(); err != nil {
+			c.WaitError = err
+		}
+		close(c.WaitLock)
+	}()
+
+	return nil
+}
+
+func (d *driver) Kill(p *execdriver.Process, sig int) error {
+	return p.Process.Kill()
+}
+
+func (d *driver) Wait(id string, duration time.Duration) error {
+	panic("No Implemented")
+}
+
+func (d *driver) Version() string {
+	return "0.1"
+}

execdriver/driver.go

@@ -36,6 +36,7 @@ type Process struct {
 	ConfigPath  string
 	Tty         bool
 	Network     *Network // if network is nil then networking is disabled
+	SysInitPath string
 	WaitLock    chan struct{}
 	WaitError   error
 }

execdriver/lxc/driver.go

@@ -88,7 +88,6 @@ func (d *driver) Start(c *execdriver.Process) error {
 		params = []string{
 			"unshare", "-m", "--", "/bin/sh", "-c", shellString,
 		}
-
 	}
 
 	params = append(params, "--", c.Entrypoint)

runtime.go

@@ -6,6 +6,7 @@ import (
 	"github.com/dotcloud/docker/archive"
 	"github.com/dotcloud/docker/cgroups"
 	"github.com/dotcloud/docker/execdriver"
+	"github.com/dotcloud/docker/execdriver/chroot"
 	"github.com/dotcloud/docker/execdriver/lxc"
 	"github.com/dotcloud/docker/graphdriver"
 	"github.com/dotcloud/docker/graphdriver/aufs"
@@ -735,7 +736,12 @@ func NewRuntimeFromDirectory(config *DaemonConfig) (*Runtime, error) {
 	}
 
 	capabilities := NewRuntimeCapabilities(false)
-	ed, err := lxc.NewDriver(config.Root, capabilities.AppArmor)
+	var ed execdriver.Driver
+	if driver := os.Getenv("EXEC_DRIVER"); driver == "lxc" {
+		ed, err = lxc.NewDriver(config.Root, capabilities.AppArmor)
+	} else {
+		ed, err = chroot.NewDriver()
+	}
 	if err != nil {
 		return nil, err
 	}

sysinit/sysinit.go

@@ -182,6 +182,7 @@ func getEnv(args *DockerInitArgs, key string) string {
 func executeProgram(args *DockerInitArgs) error {
 	setupEnv(args)
 
+	if false {
 		if err := setupHostname(args); err != nil {
 			return err
 		}
@@ -193,7 +194,6 @@ func executeProgram(args *DockerInitArgs) error {
 		if err := setupCapabilities(args); err != nil {
 			return err
 		}
-
 		if err := setupWorkingDirectory(args); err != nil {
 			return err
 		}
@@ -201,6 +201,7 @@ func executeProgram(args *DockerInitArgs) error {
 		if err := changeUser(args); err != nil {
 			return err
 		}
+	}
 
 	path, err := exec.LookPath(args.args[0])
 	if err != nil {