Require containerd id as arg 1

Closes #532

This requires the container id to always be passed to all runc commands
as arg one on the cli.  This was the result of the last OCI meeting and
how operations work with the spec.

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

README.md

@@ -65,9 +65,11 @@ You can also run specific test cases by:
 
 ### Using:
 
-To run a container, execute `runc start` in the bundle's root directory:
+To run a container with the id "test", execute `runc start` with the containers id as arg one 
+in the bundle's root directory:
+
 ```bash
-runc start
+runc start test
 / $ ps
 PID   USER     COMMAND
 1     daemon   sh
@@ -98,7 +100,7 @@ tar -C rootfs -xf busybox.tar
 * Create `config.json` by using `runc spec`.
 * Execute `runc start` and you should be placed into a shell where you can run `ps`:
 ```
-$ runc start
+$ runc start test
 / # ps
 PID   USER     COMMAND
     1 root     sh
@@ -120,7 +122,7 @@ After=network.target
 [Service]
 CPUQuota=200%
 MemoryLimit=1536M
-ExecStart=/usr/local/bin/runc start
+ExecStart=/usr/local/bin/runc start minecraft
 Restart=on-failure
 WorkingDirectory=/containers/minecraftbuild
 

exec.go

@@ -128,7 +128,7 @@ func getProcess(context *cli.Context, bundle string) (*specs.Process, error) {
 		return nil, err
 	}
 	p := spec.Process
-	p.Args = context.Args()
+	p.Args = context.Args()[1:]
 	// override the cwd, if passed
 	if context.String("cwd") != "" {
 		p.Cwd = context.String("cwd")

kill.go

@@ -58,7 +58,7 @@ var killCommand = cli.Command{
 			fatal(err)
 		}
 
-		sigstr := context.Args().First()
+		sigstr := context.Args().Get(1)
 		if sigstr == "" {
 			sigstr = "SIGTERM"
 		}

main.go

@@ -27,7 +27,7 @@ After creating config files for your root filesystem with runc, you can execute
 a container in your shell by running:
 
     # cd /mycontainer
-    # runc start [ -b bundle ] 
+    # runc start [ -b bundle ] <container-id>
 
 If not specified, the default value for the 'bundle' is the current directory.
 'Bundle' is the directory where '` + specConfig + `' must be located.`
@@ -39,11 +39,6 @@ func main() {
 	app.Usage = usage
 	app.Version = fmt.Sprintf("%s\nspec version %s", version, specs.Version)
 	app.Flags = []cli.Flag{
-		cli.StringFlag{
-			Name:  "id",
-			Value: getDefaultID(),
-			Usage: "specify the ID to be used for the container",
-		},
 		cli.BoolFlag{
 			Name:  "debug",
 			Usage: "enable debug output for logging",

main_unsupported.go

@@ -7,10 +7,6 @@ import (
 	"github.com/codegangsta/cli"
 )
 
-func getDefaultID() string {
-	return ""
-}
-
 var (
 	checkpointCommand cli.Command
 	eventsCommand     cli.Command

restore.go

@@ -66,6 +66,10 @@ var restoreCommand = cli.Command{
 	},
 	Action: func(context *cli.Context) {
 		imagePath := context.String("image-path")
+		id := context.Args().First()
+		if id == "" {
+			fatal(errEmptyID)
+		}
 		if imagePath == "" {
 			imagePath = getDefaultImagePath(context)
 		}
@@ -79,7 +83,7 @@ var restoreCommand = cli.Command{
 		if err != nil {
 			fatal(err)
 		}
-		config, err := createLibcontainerConfig(context.GlobalString("id"), spec)
+		config, err := createLibcontainerConfig(id, spec)
 		if err != nil {
 			fatal(err)
 		}
@@ -92,14 +96,17 @@ var restoreCommand = cli.Command{
 }
 
 func restoreContainer(context *cli.Context, spec *specs.LinuxSpec, config *configs.Config, imagePath string) (code int, err error) {
-	rootuid := 0
+	var (
+		rootuid = 0
+		id      = context.Args().First()
+	)
 	factory, err := loadFactory(context)
 	if err != nil {
 		return -1, err
 	}
-	container, err := factory.Load(context.GlobalString("id"))
+	container, err := factory.Load(id)
 	if err != nil {
-		container, err = factory.Create(context.GlobalString("id"), config)
+		container, err = factory.Create(id, config)
 		if err != nil {
 			return -1, err
 		}
@@ -111,7 +118,7 @@ func restoreContainer(context *cli.Context, spec *specs.LinuxSpec, config *confi
 		logrus.Error(err)
 	}
 	if status == libcontainer.Running {
-		fatal(fmt.Errorf("Container with id %s already running", context.GlobalString("id")))
+		fatal(fmt.Errorf("Container with id %s already running", id))
 	}
 
 	setManageCgroupsMode(context, options)

start.go

@@ -93,13 +93,17 @@ func init() {
 }
 
 func startContainer(context *cli.Context, spec *specs.LinuxSpec) (int, error) {
-	config, err := createLibcontainerConfig(context.GlobalString("id"), spec)
+	id := context.Args().First()
+	if id == "" {
+		return -1, errEmptyID
+	}
+	config, err := createLibcontainerConfig(id, spec)
 	if err != nil {
 		return -1, err
 	}
 	if _, err := os.Stat(config.Rootfs); err != nil {
 		if os.IsNotExist(err) {
-			return -1, fmt.Errorf("Rootfs (%q) does not exist", config.Rootfs)
+			return -1, fmt.Errorf("rootfs (%q) does not exist", config.Rootfs)
 		}
 		return -1, err
 	}
@@ -111,7 +115,7 @@ func startContainer(context *cli.Context, spec *specs.LinuxSpec) (int, error) {
 	if err != nil {
 		return -1, err
 	}
-	container, err := factory.Create(context.GlobalString("id"), config)
+	container, err := factory.Create(id, config)
 	if err != nil {
 		return -1, err
 	}

utils.go

@@ -3,6 +3,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -17,6 +18,8 @@ import (
 
 const wildcard = -1
 
+var errEmptyID = errors.New("container id cannot be empty")
+
 var allowedDevices = []*configs.Device{
 	// allow mknod for any device
 	{
@@ -160,15 +163,15 @@ func loadFactory(context *cli.Context) (libcontainer.Factory, error) {
 // getContainer returns the specified container instance by loading it from state
 // with the default factory.
 func getContainer(context *cli.Context) (libcontainer.Container, error) {
+	id := context.Args().First()
+	if id == "" {
+		return nil, errEmptyID
+	}
 	factory, err := loadFactory(context)
 	if err != nil {
 		return nil, err
 	}
-	container, err := factory.Load(context.GlobalString("id"))
-	if err != nil {
-		return nil, err
-	}
-	return container, nil
+	return factory.Load(id)
 }
 
 // fatal prints the error's details if it is a libcontainer specific error type
@@ -182,17 +185,6 @@ func fatal(err error) {
 	os.Exit(1)
 }
 
-// getDefaultID returns a string to be used as the container id based on the
-// current working directory of the runc process.  This function panics
-// if the cwd is unable to be found based on a system error.
-func getDefaultID() string {
-	cwd, err := os.Getwd()
-	if err != nil {
-		panic(err)
-	}
-	return filepath.Base(cwd)
-}
-
 func getDefaultImagePath(context *cli.Context) string {
 	cwd, err := os.Getwd()
 	if err != nil {