Initial commit of libcontainer

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

libcontainer/cli/main.go

@@ -0,0 +1,171 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"github.com/dotcloud/docker/pkg/libcontainer"
+	"github.com/dotcloud/docker/pkg/libcontainer/namespaces"
+	"github.com/dotcloud/docker/pkg/libcontainer/network"
+	"github.com/dotcloud/docker/pkg/libcontainer/utils"
+	"os"
+)
+
+var (
+	displayPid bool
+	newCommand string
+	usrNet     bool
+)
+
+func init() {
+	flag.BoolVar(&displayPid, "pid", false, "display the pid before waiting")
+	flag.StringVar(&newCommand, "cmd", "/bin/bash", "command to run in the existing namespace")
+	flag.BoolVar(&usrNet, "net", false, "user a net namespace")
+	flag.Parse()
+}
+
+func exec(container *libcontainer.Container) error {
+	var (
+		netFile *os.File
+		err     error
+	)
+	container.NetNsFd = 0
+
+	if usrNet {
+		netFile, err = os.Open("/root/nsroot/test")
+		if err != nil {
+			return err
+		}
+		container.NetNsFd = netFile.Fd()
+	}
+
+	pid, err := namespaces.Exec(container)
+	if err != nil {
+		return fmt.Errorf("error exec container %s", err)
+	}
+
+	if displayPid {
+		fmt.Println(pid)
+	}
+
+	exitcode, err := utils.WaitOnPid(pid)
+	if err != nil {
+		return fmt.Errorf("error waiting on child %s", err)
+	}
+	fmt.Println(exitcode)
+	if usrNet {
+		netFile.Close()
+		if err := network.DeleteNetworkNamespace("/root/nsroot/test"); err != nil {
+			return err
+		}
+	}
+	os.Exit(exitcode)
+	return nil
+}
+
+func execIn(container *libcontainer.Container) error {
+	f, err := os.Open("/root/nsroot/test")
+	if err != nil {
+		return err
+	}
+	container.NetNsFd = f.Fd()
+	pid, err := namespaces.ExecIn(container, &libcontainer.Command{
+		Env: container.Command.Env,
+		Args: []string{
+			newCommand,
+		},
+	})
+	if err != nil {
+		return fmt.Errorf("error exexin container %s", err)
+	}
+	exitcode, err := utils.WaitOnPid(pid)
+	if err != nil {
+		return fmt.Errorf("error waiting on child %s", err)
+	}
+	os.Exit(exitcode)
+	return nil
+}
+
+func createNet(config *libcontainer.Network) error {
+	root := "/root/nsroot"
+	if err := network.SetupNamespaceMountDir(root); err != nil {
+		return err
+	}
+
+	nspath := root + "/test"
+	if err := network.CreateNetworkNamespace(nspath); err != nil {
+		return nil
+	}
+	if err := network.CreateVethPair("veth0", config.TempVethName); err != nil {
+		return err
+	}
+	if err := network.SetInterfaceMaster("veth0", config.Bridge); err != nil {
+		return err
+	}
+	if err := network.InterfaceUp("veth0"); err != nil {
+		return err
+	}
+
+	f, err := os.Open(nspath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if err := network.SetInterfaceInNamespaceFd("veth1", int(f.Fd())); err != nil {
+		return err
+	}
+
+	/*
+		if err := network.SetupVethInsideNamespace(f.Fd(), config); err != nil {
+			return err
+		}
+	*/
+	return nil
+}
+
+func printErr(err error) {
+	fmt.Fprintln(os.Stderr, err)
+	os.Exit(1)
+}
+
+func main() {
+	var (
+		err    error
+		cliCmd = flag.Arg(0)
+		config = flag.Arg(1)
+	)
+	f, err := os.Open(config)
+	if err != nil {
+		printErr(err)
+	}
+
+	dec := json.NewDecoder(f)
+	var container *libcontainer.Container
+
+	if err := dec.Decode(&container); err != nil {
+		printErr(err)
+	}
+	f.Close()
+
+	switch cliCmd {
+	case "exec":
+		err = exec(container)
+	case "execin":
+		err = execIn(container)
+	case "net":
+		err = createNet(&libcontainer.Network{
+			TempVethName: "veth1",
+			IP:           "172.17.0.100/16",
+			Gateway:      "172.17.42.1",
+			Mtu:          1500,
+			Bridge:       "docker0",
+		})
+	default:
+		err = fmt.Errorf("command not supported: %s", cliCmd)
+	}
+
+	if err != nil {
+		printErr(err)
+	}
+}