blob: 0fd1fbfadf193a08e9270236882d0d4320e13927 [file] [log] [blame]
// +build linux
package main
import (
"errors"
"fmt"
"os"
"path/filepath"
"syscall"
"github.com/Sirupsen/logrus"
"github.com/codegangsta/cli"
"github.com/coreos/go-systemd/activation"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
"github.com/opencontainers/runc/libcontainer/specconv"
"github.com/opencontainers/runtime-spec/specs-go"
)
var errEmptyID = errors.New("container id cannot be empty")
var container libcontainer.Container
// loadFactory returns the configured factory instance for execing containers.
func loadFactory(context *cli.Context) (libcontainer.Factory, error) {
root := context.GlobalString("root")
abs, err := filepath.Abs(root)
if err != nil {
return nil, err
}
cgroupManager := libcontainer.Cgroupfs
if context.GlobalBool("systemd-cgroup") {
if systemd.UseSystemd() {
cgroupManager = libcontainer.SystemdCgroups
} else {
return nil, fmt.Errorf("systemd cgroup flag passed, but systemd support for managing cgroups is not available")
}
}
return libcontainer.New(abs, cgroupManager, func(l *libcontainer.LinuxFactory) error {
l.CriuPath = context.GlobalString("criu")
return nil
})
}
// 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
}
return factory.Load(id)
}
func fatalf(t string, v ...interface{}) {
fatal(fmt.Errorf(t, v...))
}
func getDefaultImagePath(context *cli.Context) string {
cwd, err := os.Getwd()
if err != nil {
panic(err)
}
return filepath.Join(cwd, "checkpoint")
}
// newProcess returns a new libcontainer Process with the arguments from the
// spec and stdio from the current process.
func newProcess(p specs.Process) (*libcontainer.Process, error) {
lp := &libcontainer.Process{
Args: p.Args,
Env: p.Env,
// TODO: fix libcontainer's API to better support uid/gid in a typesafe way.
User: fmt.Sprintf("%d:%d", p.User.UID, p.User.GID),
Cwd: p.Cwd,
Capabilities: p.Capabilities,
Label: p.SelinuxLabel,
NoNewPrivileges: &p.NoNewPrivileges,
AppArmorProfile: p.ApparmorProfile,
}
for _, rlimit := range p.Rlimits {
rl, err := createLibContainerRlimit(rlimit)
if err != nil {
return nil, err
}
lp.Rlimits = append(lp.Rlimits, rl)
}
return lp, nil
}
func dupStdio(process *libcontainer.Process, rootuid, rootgid int) error {
process.Stdin = os.Stdin
process.Stdout = os.Stdout
process.Stderr = os.Stderr
for _, fd := range []uintptr{
os.Stdin.Fd(),
os.Stdout.Fd(),
os.Stderr.Fd(),
} {
if err := syscall.Fchown(int(fd), rootuid, rootgid); err != nil {
return err
}
}
return nil
}
// If systemd is supporting sd_notify protocol, this function will add support
// for sd_notify protocol from within the container.
func setupSdNotify(spec *specs.Spec, notifySocket string) {
spec.Mounts = append(spec.Mounts, specs.Mount{Destination: notifySocket, Type: "bind", Source: notifySocket, Options: []string{"bind"}})
spec.Process.Env = append(spec.Process.Env, fmt.Sprintf("NOTIFY_SOCKET=%s", notifySocket))
}
func destroy(container libcontainer.Container) {
if err := container.Destroy(); err != nil {
logrus.Error(err)
}
}
// setupIO sets the proper IO on the process depending on the configuration
// If there is a nil error then there must be a non nil tty returned
func setupIO(process *libcontainer.Process, rootuid, rootgid int, console string, createTTY, detach bool) (*tty, error) {
// detach and createTty will not work unless a console path is passed
// so error out here before changing any terminal settings
if createTTY && detach && console == "" {
return nil, fmt.Errorf("cannot allocate tty if runc will detach")
}
if createTTY {
return createTty(process, rootuid, rootgid, console)
}
if detach {
if err := dupStdio(process, rootuid, rootgid); err != nil {
return nil, err
}
return &tty{}, nil
}
return createStdioPipes(process, rootuid, rootgid)
}
// createPidFile creates a file with the processes pid inside it atomically
// it creates a temp file with the paths filename + '.' infront of it
// then renames the file
func createPidFile(path string, process *libcontainer.Process) error {
pid, err := process.Pid()
if err != nil {
return err
}
var (
tmpDir = filepath.Dir(path)
tmpName = filepath.Join(tmpDir, fmt.Sprintf(".%s", filepath.Base(path)))
)
f, err := os.OpenFile(tmpName, os.O_RDWR|os.O_CREATE|os.O_EXCL|os.O_SYNC, 0666)
if err != nil {
return err
}
_, err = fmt.Fprintf(f, "%d", pid)
f.Close()
if err != nil {
return err
}
return os.Rename(tmpName, path)
}
func createContainer(context *cli.Context, id string, spec *specs.Spec) (libcontainer.Container, error) {
config, err := specconv.CreateLibcontainerConfig(&specconv.CreateOpts{
CgroupName: id,
UseSystemdCgroup: context.GlobalBool("systemd-cgroup"),
NoPivotRoot: context.Bool("no-pivot"),
Spec: spec,
})
if err != nil {
return nil, err
}
if _, err := os.Stat(config.Rootfs); err != nil {
if os.IsNotExist(err) {
return nil, fmt.Errorf("rootfs (%q) does not exist", config.Rootfs)
}
return nil, err
}
factory, err := loadFactory(context)
if err != nil {
return nil, err
}
return factory.Create(id, config)
}
type runner struct {
enableSubreaper bool
shouldDestroy bool
detach bool
listenFDs []*os.File
pidFile string
console string
container libcontainer.Container
create bool
}
func (r *runner) run(config *specs.Process) (int, error) {
process, err := newProcess(*config)
if err != nil {
r.destroy()
return -1, err
}
if len(r.listenFDs) > 0 {
process.Env = append(process.Env, fmt.Sprintf("LISTEN_FDS=%d", len(r.listenFDs)), "LISTEN_PID=1")
process.ExtraFiles = append(process.ExtraFiles, r.listenFDs...)
}
rootuid, err := r.container.Config().HostUID()
if err != nil {
r.destroy()
return -1, err
}
rootgid, err := r.container.Config().HostGID()
if err != nil {
r.destroy()
return -1, err
}
tty, err := setupIO(process, rootuid, rootgid, r.console, config.Terminal, r.detach || r.create)
if err != nil {
r.destroy()
return -1, err
}
handler := newSignalHandler(tty, r.enableSubreaper)
if err := r.container.Start(process); err != nil {
r.destroy()
tty.Close()
return -1, err
}
if err := tty.ClosePostStart(); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
if r.pidFile != "" {
if err := createPidFile(r.pidFile, process); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
}
if !r.create {
if err := process.Signal(libcontainer.InitContinueSignal); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
}
if r.detach || r.create {
tty.Close()
return 0, nil
}
status, err := handler.forward(process)
if err != nil {
r.terminate(process)
}
r.destroy()
tty.Close()
return status, err
}
func (r *runner) destroy() {
if r.shouldDestroy {
destroy(r.container)
}
}
func (r *runner) terminate(p *libcontainer.Process) {
p.Signal(syscall.SIGKILL)
p.Wait()
}
func validateProcessSpec(spec *specs.Process) error {
if spec.Cwd == "" {
return fmt.Errorf("Cwd property must not be empty")
}
if !filepath.IsAbs(spec.Cwd) {
return fmt.Errorf("Cwd must be an absolute path")
}
if len(spec.Args) == 0 {
return fmt.Errorf("args must not be empty")
}
return nil
}
func startContainer(context *cli.Context, spec *specs.Spec, create bool) (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"),
create: create,
}
return r.run(&spec.Process)
}