libct: Container, Factory: rm InitPath, InitArgs

Those are *always* /proc/self/exe init, and it does not make sense
to ever change these. More to say, if InitArgs option func (removed
by this commit) is used to change these parameters, it will break
things, since "init" is hardcoded elsewhere.

Remove this.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

libcontainer/README.md

@@ -45,7 +45,7 @@ Then to create a container you first have to initialize an instance of a factory
 that will handle the creation and initialization for a container.
 
 ```go
-factory, err := libcontainer.New("/var/lib/container", libcontainer.InitArgs(os.Args[0], "init"))
+factory, err := libcontainer.New("/var/lib/container")
 if err != nil {
 	logrus.Fatal(err)
 	return

libcontainer/container_linux.go

@@ -41,8 +41,6 @@ type linuxContainer struct {
 	config               *configs.Config
 	cgroupManager        cgroups.Manager
 	intelRdtManager      intelrdt.Manager
-	initPath             string
-	initArgs             []string
 	initProcess          parentProcess
 	initProcessStartTime uint64
 	newuidmapPath        string
@@ -481,8 +479,8 @@ func (c *linuxContainer) newParentProcess(p *Process) (parentProcess, error) {
 }
 
 func (c *linuxContainer) commandTemplate(p *Process, childInitPipe *os.File, childLogPipe *os.File) *exec.Cmd {
-	cmd := exec.Command(c.initPath, c.initArgs[1:]...)
-	cmd.Args[0] = c.initArgs[0]
+	cmd := exec.Command("/proc/self/exe", "init")
+	cmd.Args[0] = os.Args[0]
 	cmd.Stdin = p.Stdin
 	cmd.Stdout = p.Stdout
 	cmd.Stderr = p.Stderr

libcontainer/factory_linux.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"os"
-	"path/filepath"
 	"regexp"
 	"runtime/debug"
 	"strconv"
@@ -29,25 +28,6 @@ const (
 
 var idRegex = regexp.MustCompile(`^[\w+-\.]+$`)
 
-// InitArgs returns an options func to configure a LinuxFactory with the
-// provided init binary path and arguments.
-func InitArgs(args ...string) func(*LinuxFactory) error {
-	return func(l *LinuxFactory) (err error) {
-		if len(args) > 0 {
-			// Resolve relative paths to ensure that its available
-			// after directory changes.
-			if args[0], err = filepath.Abs(args[0]); err != nil {
-				// The only error returned from filepath.Abs is
-				// the one from os.Getwd, i.e. a system error.
-				return err
-			}
-		}
-
-		l.InitArgs = args
-		return nil
-	}
-}
-
 // IntelRdtfs is an options func to configure a LinuxFactory to return
 // containers that use the Intel RDT "resource control" filesystem to
 // create and manage Intel RDT resources (e.g., L3 cache, memory bandwidth).
@@ -86,8 +66,6 @@ func New(root string, options ...func(*LinuxFactory) error) (Factory, error) {
 	}
 	l := &LinuxFactory{
 		Root:      root,
-		InitPath:  "/proc/self/exe",
-		InitArgs:  []string{os.Args[0], "init"},
 		Validator: validate.New(),
 	}
 
@@ -107,14 +85,6 @@ type LinuxFactory struct {
 	// Root directory for the factory to store state.
 	Root string
 
-	// InitPath is the path for calling the init responsibilities for spawning
-	// a container.
-	InitPath string
-
-	// InitArgs are arguments for calling the init responsibilities for spawning
-	// a container.
-	InitArgs []string
-
 	// New{u,g}idmapPath is the path to the binaries used for mapping with
 	// rootless containers.
 	NewuidmapPath string
@@ -188,8 +158,6 @@ func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, err
 		id:            id,
 		root:          containerRoot,
 		config:        config,
-		initPath:      l.InitPath,
-		initArgs:      l.InitArgs,
 		newuidmapPath: l.NewuidmapPath,
 		newgidmapPath: l.NewgidmapPath,
 		cgroupManager: cm,
@@ -231,8 +199,6 @@ func (l *LinuxFactory) Load(id string) (Container, error) {
 		initProcessStartTime: state.InitProcessStartTime,
 		id:                   id,
 		config:               &state.Config,
-		initPath:             l.InitPath,
-		initArgs:             l.InitArgs,
 		newuidmapPath:        l.NewuidmapPath,
 		newgidmapPath:        l.NewgidmapPath,
 		cgroupManager:        cm,