359 lines
9.2 KiB
Go
359 lines
9.2 KiB
Go
// +build linux
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package main
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import (
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"errors"
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"fmt"
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"net"
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"os"
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"path/filepath"
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"strconv"
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"syscall"
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"github.com/Sirupsen/logrus"
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"github.com/coreos/go-systemd/activation"
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"github.com/opencontainers/runc/libcontainer"
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"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
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"github.com/opencontainers/runc/libcontainer/specconv"
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"github.com/opencontainers/runtime-spec/specs-go"
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"github.com/urfave/cli"
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)
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var errEmptyID = errors.New("container id cannot be empty")
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var container libcontainer.Container
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// loadFactory returns the configured factory instance for execing containers.
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func loadFactory(context *cli.Context) (libcontainer.Factory, error) {
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root := context.GlobalString("root")
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abs, err := filepath.Abs(root)
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if err != nil {
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return nil, err
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}
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cgroupManager := libcontainer.Cgroupfs
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if context.GlobalBool("systemd-cgroup") {
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if systemd.UseSystemd() {
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cgroupManager = libcontainer.SystemdCgroups
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} else {
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return nil, fmt.Errorf("systemd cgroup flag passed, but systemd support for managing cgroups is not available")
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}
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}
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return libcontainer.New(abs, cgroupManager, libcontainer.CriuPath(context.GlobalString("criu")))
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}
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// getContainer returns the specified container instance by loading it from state
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// with the default factory.
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func getContainer(context *cli.Context) (libcontainer.Container, error) {
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id := context.Args().First()
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if id == "" {
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return nil, errEmptyID
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}
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factory, err := loadFactory(context)
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if err != nil {
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return nil, err
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}
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return factory.Load(id)
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}
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func fatalf(t string, v ...interface{}) {
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fatal(fmt.Errorf(t, v...))
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}
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func getDefaultImagePath(context *cli.Context) string {
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cwd, err := os.Getwd()
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if err != nil {
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panic(err)
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}
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return filepath.Join(cwd, "checkpoint")
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}
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// newProcess returns a new libcontainer Process with the arguments from the
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// spec and stdio from the current process.
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func newProcess(p specs.Process) (*libcontainer.Process, error) {
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lp := &libcontainer.Process{
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Args: p.Args,
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Env: p.Env,
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// TODO: fix libcontainer's API to better support uid/gid in a typesafe way.
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User: fmt.Sprintf("%d:%d", p.User.UID, p.User.GID),
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Cwd: p.Cwd,
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Capabilities: p.Capabilities,
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Label: p.SelinuxLabel,
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NoNewPrivileges: &p.NoNewPrivileges,
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AppArmorProfile: p.ApparmorProfile,
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}
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for _, gid := range p.User.AdditionalGids {
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lp.AdditionalGroups = append(lp.AdditionalGroups, strconv.FormatUint(uint64(gid), 10))
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}
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for _, rlimit := range p.Rlimits {
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rl, err := createLibContainerRlimit(rlimit)
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if err != nil {
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return nil, err
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}
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lp.Rlimits = append(lp.Rlimits, rl)
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}
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return lp, nil
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}
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// If systemd is supporting sd_notify protocol, this function will add support
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// for sd_notify protocol from within the container.
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func setupSdNotify(spec *specs.Spec, notifySocket string) {
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spec.Mounts = append(spec.Mounts, specs.Mount{Destination: notifySocket, Type: "bind", Source: notifySocket, Options: []string{"bind"}})
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spec.Process.Env = append(spec.Process.Env, fmt.Sprintf("NOTIFY_SOCKET=%s", notifySocket))
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}
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func destroy(container libcontainer.Container) {
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if err := container.Destroy(); err != nil {
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logrus.Error(err)
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}
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}
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// setupIO modifies the given process config according to the options.
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func setupIO(process *libcontainer.Process, rootuid, rootgid int, createTTY, detach bool) (*tty, error) {
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// This is entirely handled by recvtty.
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if createTTY {
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process.Stdin = nil
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process.Stdout = nil
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process.Stderr = nil
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return &tty{}, nil
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}
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// When we detach, we just dup over stdio and call it a day. There's no
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// requirement that we set up anything nice for our caller or the
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// container.
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if detach {
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if err := dupStdio(process, rootuid, rootgid); err != nil {
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return nil, err
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}
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return &tty{}, nil
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}
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// XXX: This doesn't sit right with me. It's ugly.
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return createStdioPipes(process, rootuid, rootgid)
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}
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// createPidFile creates a file with the processes pid inside it atomically
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// it creates a temp file with the paths filename + '.' infront of it
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// then renames the file
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func createPidFile(path string, process *libcontainer.Process) error {
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pid, err := process.Pid()
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if err != nil {
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return err
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}
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var (
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tmpDir = filepath.Dir(path)
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tmpName = filepath.Join(tmpDir, fmt.Sprintf(".%s", filepath.Base(path)))
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)
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f, err := os.OpenFile(tmpName, os.O_RDWR|os.O_CREATE|os.O_EXCL|os.O_SYNC, 0666)
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if err != nil {
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return err
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}
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_, err = fmt.Fprintf(f, "%d", pid)
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f.Close()
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if err != nil {
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return err
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}
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return os.Rename(tmpName, path)
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}
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func createContainer(context *cli.Context, id string, spec *specs.Spec) (libcontainer.Container, error) {
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config, err := specconv.CreateLibcontainerConfig(&specconv.CreateOpts{
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CgroupName: id,
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UseSystemdCgroup: context.GlobalBool("systemd-cgroup"),
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NoPivotRoot: context.Bool("no-pivot"),
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NoNewKeyring: context.Bool("no-new-keyring"),
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Spec: spec,
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})
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if err != nil {
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return nil, err
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}
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factory, err := loadFactory(context)
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if err != nil {
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return nil, err
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}
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return factory.Create(id, config)
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}
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type runner struct {
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enableSubreaper bool
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shouldDestroy bool
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detach bool
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listenFDs []*os.File
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pidFile string
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consoleSocket string
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container libcontainer.Container
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create bool
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}
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func (r *runner) terminalinfo() *libcontainer.TerminalInfo {
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return libcontainer.NewTerminalInfo(r.container.ID())
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}
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func (r *runner) run(config *specs.Process) (int, error) {
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process, err := newProcess(*config)
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if err != nil {
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r.destroy()
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return -1, err
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}
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if len(r.listenFDs) > 0 {
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process.Env = append(process.Env, fmt.Sprintf("LISTEN_FDS=%d", len(r.listenFDs)), "LISTEN_PID=1")
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process.ExtraFiles = append(process.ExtraFiles, r.listenFDs...)
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}
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rootuid, err := r.container.Config().HostUID()
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if err != nil {
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r.destroy()
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return -1, err
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}
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rootgid, err := r.container.Config().HostGID()
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if err != nil {
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r.destroy()
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return -1, err
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}
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detach := r.detach || r.create
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// Check command-line for sanity.
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if detach && config.Terminal && r.consoleSocket == "" {
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r.destroy()
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return -1, fmt.Errorf("cannot allocate tty if runc will detach without setting console socket")
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}
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// XXX: Should we change this?
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if (!detach || !config.Terminal) && r.consoleSocket != "" {
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r.destroy()
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return -1, fmt.Errorf("cannot use console socket if runc will not detach or allocate tty")
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}
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startFn := r.container.Start
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if !r.create {
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startFn = r.container.Run
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}
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// Setting up IO is a two stage process. We need to modify process to deal
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// with detaching containers, and then we get a tty after the container has
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// started.
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handler := newSignalHandler(r.enableSubreaper)
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tty, err := setupIO(process, rootuid, rootgid, config.Terminal, detach)
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if err != nil {
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r.destroy()
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return -1, err
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}
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defer tty.Close()
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if err = startFn(process); err != nil {
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r.destroy()
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return -1, err
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}
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if config.Terminal {
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if err = tty.recvtty(process, r.detach || r.create); err != nil {
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r.terminate(process)
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r.destroy()
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return -1, err
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}
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}
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if config.Terminal && detach {
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conn, err := net.Dial("unix", r.consoleSocket)
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if err != nil {
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r.terminate(process)
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r.destroy()
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return -1, err
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}
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defer conn.Close()
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unixconn, ok := conn.(*net.UnixConn)
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if !ok {
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r.terminate(process)
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r.destroy()
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return -1, fmt.Errorf("casting to UnixConn failed")
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}
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socket, err := unixconn.File()
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if err != nil {
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r.terminate(process)
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r.destroy()
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return -1, err
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}
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defer socket.Close()
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err = tty.sendtty(socket, r.terminalinfo())
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if err != nil {
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r.terminate(process)
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r.destroy()
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return -1, err
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}
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}
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if err = tty.ClosePostStart(); err != nil {
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r.terminate(process)
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r.destroy()
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return -1, err
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}
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if r.pidFile != "" {
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if err = createPidFile(r.pidFile, process); err != nil {
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r.terminate(process)
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r.destroy()
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return -1, err
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}
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}
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if detach {
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return 0, nil
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}
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status, err := handler.forward(process, tty)
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if err != nil {
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r.terminate(process)
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}
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r.destroy()
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return status, err
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}
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func (r *runner) destroy() {
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if r.shouldDestroy {
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destroy(r.container)
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}
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}
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func (r *runner) terminate(p *libcontainer.Process) {
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_ = p.Signal(syscall.SIGKILL)
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_, _ = p.Wait()
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}
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func validateProcessSpec(spec *specs.Process) error {
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if spec.Cwd == "" {
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return fmt.Errorf("Cwd property must not be empty")
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}
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if !filepath.IsAbs(spec.Cwd) {
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return fmt.Errorf("Cwd must be an absolute path")
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}
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if len(spec.Args) == 0 {
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return fmt.Errorf("args must not be empty")
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}
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return nil
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}
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func startContainer(context *cli.Context, spec *specs.Spec, create bool) (int, error) {
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id := context.Args().First()
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if id == "" {
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return -1, errEmptyID
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}
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container, err := createContainer(context, id, spec)
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if err != nil {
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return -1, err
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}
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// Support on-demand socket activation by passing file descriptors into the container init process.
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listenFDs := []*os.File{}
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if os.Getenv("LISTEN_FDS") != "" {
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listenFDs = activation.Files(false)
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}
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r := &runner{
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enableSubreaper: !context.Bool("no-subreaper"),
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shouldDestroy: true,
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container: container,
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listenFDs: listenFDs,
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consoleSocket: context.String("console-socket"),
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detach: context.Bool("detach"),
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pidFile: context.String("pid-file"),
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create: create,
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}
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return r.run(&spec.Process)
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}
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