Rename start to run

`runc run` is the command that will create and start a container in one
single command.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

run.go

@@ -0,0 +1,116 @@
+// +build linux
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/codegangsta/cli"
+	"github.com/coreos/go-systemd/activation"
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+// default action is to start a container
+var runCommand = cli.Command{
+	Name:  "run",
+	Usage: "create and run a container",
+	ArgsUsage: `<container-id>
+
+Where "<container-id>" is your name for the instance of the container that you
+are starting. The name you provide for the container instance must be unique on
+your host.`,
+	Description: `The run command creates an instance of a container for a bundle. The bundle
+is a directory with a specification file named "` + specConfig + `" and a root
+filesystem.
+
+The specification file includes an args parameter. The args parameter is used
+to specify command(s) that get run when the container is started. To change the
+command(s) that get executed on start, edit the args parameter of the spec. See
+"runc spec --help" for more explanation.`,
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:  "bundle, b",
+			Value: "",
+			Usage: `path to the root of the bundle directory, defaults to the current directory`,
+		},
+		cli.StringFlag{
+			Name:  "console",
+			Value: "",
+			Usage: "specify the pty slave path for use with the container",
+		},
+		cli.BoolFlag{
+			Name:  "detach,d",
+			Usage: "detach from the container's process",
+		},
+		cli.StringFlag{
+			Name:  "pid-file",
+			Value: "",
+			Usage: "specify the file to write the process id to",
+		},
+		cli.BoolFlag{
+			Name:  "no-subreaper",
+			Usage: "disable the use of the subreaper used to reap reparented processes",
+		},
+		cli.BoolFlag{
+			Name:  "no-pivot",
+			Usage: "do not use pivot root to jail process inside rootfs.  This should be used whenever the rootfs is on top of a ramdisk",
+		},
+	},
+	Action: func(context *cli.Context) error {
+		bundle := context.String("bundle")
+		if bundle != "" {
+			if err := os.Chdir(bundle); err != nil {
+				return err
+			}
+		}
+		spec, err := loadSpec(specConfig)
+		if err != nil {
+			return err
+		}
+
+		notifySocket := os.Getenv("NOTIFY_SOCKET")
+		if notifySocket != "" {
+			setupSdNotify(spec, notifySocket)
+		}
+
+		if os.Geteuid() != 0 {
+			return fmt.Errorf("runc should be run as root")
+		}
+
+		status, err := startContainer(context, spec)
+		if err == nil {
+			// exit with the container's exit status so any external supervisor is
+			// notified of the exit with the correct exit status.
+			os.Exit(status)
+		}
+		return err
+	},
+}
+
+func startContainer(context *cli.Context, spec *specs.Spec) (int, error) {
+	id := context.Args().First()
+	if id == "" {
+		return -1, errEmptyID
+	}
+	container, err := createContainer(context, id, spec)
+	if err != nil {
+		return -1, err
+	}
+	detach := context.Bool("detach")
+	// Support on-demand socket activation by passing file descriptors into the container init process.
+	listenFDs := []*os.File{}
+	if os.Getenv("LISTEN_FDS") != "" {
+		listenFDs = activation.Files(false)
+	}
+	r := &runner{
+		enableSubreaper: !context.Bool("no-subreaper"),
+		shouldDestroy:   true,
+		container:       container,
+		listenFDs:       listenFDs,
+		console:         context.String("console"),
+		detach:          detach,
+		pidFile:         context.String("pid-file"),
+	}
+	return r.run(&spec.Process)
+}