func NewBuilder(podRoot string, podUUID *types.UUID) (*Builder, error) {
	pod, err := stage1commontypes.LoadPod(podRoot, podUUID)
	if err != nil {
		logs.WithError(err).Fatal("Failed to load pod")
	}
	if len(pod.Manifest.Apps) != 1 {
		logs.Fatal("dgr builder support only 1 application")
	}

	fields := data.WithField("aci", manifestApp(pod).Name)

	aciPath, ok := manifestApp(pod).App.Environment.Get(common.EnvAciPath)
	if !ok || aciPath == "" {
		return nil, errs.WithF(fields, "Builder image require "+common.EnvAciPath+" environment variable")
	}
	aciTarget, ok := manifestApp(pod).App.Environment.Get(common.EnvAciTarget)
	if !ok || aciPath == "" {
		return nil, errs.WithF(fields, "Builder image require "+common.EnvAciTarget+" environment variable")
	}

	return &Builder{
		fields:        fields,
		aciHomePath:   aciPath,
		aciTargetPath: aciTarget,
		pod:           pod,
		stage1Rootfs:  rktcommon.Stage1RootfsPath(pod.Root),
		stage2Rootfs:  filepath.Join(rktcommon.AppPath(pod.Root, manifestApp(pod).Name), "rootfs"),
	}, nil
}

// prepareAppImage renders and verifies the tree cache of the app image that
// corresponds to the given app name.
// When useOverlay is false, it attempts to render and expand the app image
func prepareAppImage(cfg PrepareConfig, appName types.ACName, img types.Hash, cdir string, useOverlay bool) error {
	log.Println("Loading image", img.String())

	if useOverlay {
		if err := cfg.Store.RenderTreeStore(img.String(), false); err != nil {
			return fmt.Errorf("error rendering tree image: %v", err)
		}
		if err := cfg.Store.CheckTreeStore(img.String()); err != nil {
			log.Printf("Warning: tree cache is in a bad state. Rebuilding...")
			if err := cfg.Store.RenderTreeStore(img.String(), true); err != nil {
				return fmt.Errorf("error rendering tree image: %v", err)
			}
		}
	} else {
		ad := common.AppPath(cdir, appName)
		err := os.MkdirAll(ad, 0755)
		if err != nil {
			return fmt.Errorf("error creating image directory: %v", err)
		}

		if err := aci.RenderACIWithImageID(img, ad, cfg.Store); err != nil {
			return fmt.Errorf("error rendering ACI: %v", err)
		}
	}
	return nil
}

// prepareAppImage renders and verifies the tree cache of the app image that
// corresponds to the given app name.
// When useOverlay is false, it attempts to render and expand the app image
func prepareAppImage(cfg PrepareConfig, appName types.ACName, img types.Hash, cdir string, useOverlay bool) error {
	log.Println("Loading image", img.String())

	am, err := cfg.Store.GetImageManifest(img.String())
	if err != nil {
		return fmt.Errorf("error getting the manifest: %v", err)
	}

	if _, hasOS := am.Labels.Get("os"); !hasOS {
		return fmt.Errorf("missing os label in the image manifest")
	}
	if _, hasArch := am.Labels.Get("arch"); !hasArch {
		return fmt.Errorf("missing arch label in the image manifest")
	}

	if err := types.IsValidOSArch(am.Labels.ToMap(), ValidOSArch); err != nil {
		return err
	}

	appInfoDir := common.AppInfoPath(cdir, appName)
	if err := os.MkdirAll(appInfoDir, 0755); err != nil {
		return fmt.Errorf("error creating apps info directory: %v", err)
	}

	if useOverlay {
		if cfg.PrivateUsers.Shift > 0 {
			return fmt.Errorf("cannot use both overlay and user namespace: not implemented yet. (Try --no-overlay)")
		}
		treeStoreID, err := cfg.Store.RenderTreeStore(img.String(), false)
		if err != nil {
			return fmt.Errorf("error rendering tree image: %v", err)
		}
		if err := cfg.Store.CheckTreeStore(treeStoreID); err != nil {
			log.Printf("Warning: tree cache is in a bad state: %v. Rebuilding...", err)
			var err error
			if treeStoreID, err = cfg.Store.RenderTreeStore(img.String(), true); err != nil {
				return fmt.Errorf("error rendering tree image: %v", err)
			}
		}

		if err := ioutil.WriteFile(common.AppTreeStoreIDPath(cdir, appName), []byte(treeStoreID), 0700); err != nil {
			return fmt.Errorf("error writing app treeStoreID: %v", err)
		}
	} else {
		ad := common.AppPath(cdir, appName)
		err := os.MkdirAll(ad, 0755)
		if err != nil {
			return fmt.Errorf("error creating image directory: %v", err)
		}

		if err := aci.RenderACIWithImageID(img, ad, cfg.Store, cfg.PrivateUsers); err != nil {
			return fmt.Errorf("error rendering ACI: %v", err)
		}
	}
	if err := writeManifest(cfg.CommonConfig, img, appInfoDir); err != nil {
		return err
	}
	return nil
}

// deletePod cleans up files and resource associated with the pod
// pod must be under exclusive lock and be in either ExitedGarbage
// or Garbage state
func deletePod(p *pod) {
	if !p.isExitedGarbage && !p.isGarbage {
		panic(fmt.Sprintf("logic error: deletePod called with non-garbage pod %q (status %q)", p.uuid, p.getState()))
	}

	if p.isExitedGarbage {
		s, err := store.NewStore(getDataDir())
		if err != nil {
			stderr("Cannot open store: %v", err)
			return
		}
		defer s.Close()
		stage1TreeStoreID, err := p.getStage1TreeStoreID()
		if err != nil {
			stderr("Error getting stage1 treeStoreID: %v", err)
			return
		}
		stage1RootFS := s.GetTreeStoreRootFS(stage1TreeStoreID)

		// execute stage1's GC
		if err := stage0.GC(p.path(), p.uuid, stage1RootFS, globalFlags.Debug); err != nil {
			stderr("Stage1 GC of pod %q failed: %v", p.uuid, err)
			return
		}

		if p.usesOverlay() {
			apps, err := p.getApps()
			if err != nil {
				stderr("Error retrieving app hashes from pod manifest: %v", err)
				return
			}
			for _, a := range apps {
				dest := filepath.Join(common.AppPath(p.path(), a.Name), "rootfs")
				if err := syscall.Unmount(dest, 0); err != nil {
					// machine could have been rebooted and mounts lost.
					// ignore "does not exist" and "not a mount point" errors
					if err != syscall.ENOENT && err != syscall.EINVAL {
						stderr("Error unmounting app at %v: %v", dest, err)
					}
				}
			}

			s1 := filepath.Join(common.Stage1ImagePath(p.path()), "rootfs")
			if err := syscall.Unmount(s1, 0); err != nil {
				// machine could have been rebooted and mounts lost.
				// ignore "does not exist" and "not a mount point" errors
				if err != syscall.ENOENT && err != syscall.EINVAL {
					stderr("Error unmounting stage1 at %v: %v", s1, err)
					return
				}
			}
		}
	}

	if err := os.RemoveAll(p.path()); err != nil {
		stderr("Unable to remove pod %q: %v", p.uuid, err)
	}
}

// setupAppImage mounts the overlay filesystem for the app image that
// corresponds to the given hash. Then, it creates the tmp directory.
// When useOverlay is false it just creates the tmp directory for this app.
func setupAppImage(cfg RunConfig, appName types.ACName, img types.Hash, cdir string, useOverlay bool) error {
	ad := common.AppPath(cdir, appName)
	if useOverlay {
		err := os.MkdirAll(ad, 0776)
		if err != nil {
			return fmt.Errorf("error creating image directory: %v", err)
		}

		if err := overlayRender(cfg, img, cdir, ad, appName.String()); err != nil {
			return fmt.Errorf("error rendering overlay filesystem: %v", err)
		}
	}

	return nil
}

// setupAppImage mounts the overlay filesystem for the app image that
// corresponds to the given hash if useOverlay is true.
// It also creates an mtab file in the application's rootfs if one is not
// present.
func setupAppImage(cfg RunConfig, appName types.ACName, img types.Hash, cdir string, useOverlay bool) error {
	ad := common.AppPath(cdir, appName)
	if useOverlay {
		err := os.MkdirAll(ad, common.DefaultRegularDirPerm)
		if err != nil {
			return errwrap.Wrap(errors.New("error creating image directory"), err)
		}
		treeStoreID, err := ioutil.ReadFile(common.AppTreeStoreIDPath(cdir, appName))
		if err != nil {
			return err
		}
		if err := copyAppManifest(cdir, appName, ad); err != nil {
			return err
		}
		if err := overlayRender(cfg, string(treeStoreID), cdir, ad, appName.String()); err != nil {
			return errwrap.Wrap(errors.New("error rendering overlay filesystem"), err)
		}
	}
	return ensureMtabExists(filepath.Join(ad, "rootfs"))
}

// setupAppImage mounts the overlay filesystem for the app image that
// corresponds to the given hash. Then, it creates the tmp directory.
// When useOverlay is false it just creates the tmp directory for this app.
func setupAppImage(cfg RunConfig, appName types.ACName, img types.Hash, cdir string, useOverlay bool) error {
	ad := common.AppPath(cdir, appName)
	if useOverlay {
		err := os.MkdirAll(ad, defaultRegularDirPerm)
		if err != nil {
			return fmt.Errorf("error creating image directory: %v", err)
		}
		treeStoreID, err := ioutil.ReadFile(common.AppTreeStoreIDPath(cdir, appName))
		if err != nil {
			return err
		}
		if err := copyAppManifest(cdir, appName, ad); err != nil {
			return err
		}
		if err := overlayRender(cfg, string(treeStoreID), cdir, ad, appName.String()); err != nil {
			return fmt.Errorf("error rendering overlay filesystem: %v", err)
		}
	}

	return nil
}

func stage1(rp *stage1commontypes.RuntimePod) int {
	uuid, err := types.NewUUID(flag.Arg(0))
	if err != nil {
		log.Print("UUID is missing or malformed\n")
		return 254
	}

	root := "."
	p, err := stage1commontypes.LoadPod(root, uuid, rp)
	if err != nil {
		log.PrintE("can't load pod", err)
		return 254
	}

	if err := p.SaveRuntime(); err != nil {
		log.FatalE("failed to save runtime parameters", err)
	}

	// Sanity checks
	if len(p.Manifest.Apps) != 1 {
		log.Printf("flavor %q only supports 1 application per Pod for now", flavor)
		return 254
	}

	ra := p.Manifest.Apps[0]

	imgName := p.AppNameToImageName(ra.Name)
	args := ra.App.Exec
	if len(args) == 0 {
		log.Printf(`image %q has an empty "exec" (try --exec=BINARY)`, imgName)
		return 254
	}

	lfd, err := common.GetRktLockFD()
	if err != nil {
		log.PrintE("can't get rkt lock fd", err)
		return 254
	}

	// set close-on-exec flag on RKT_LOCK_FD so it gets correctly closed after execution is finished
	if err := sys.CloseOnExec(lfd, true); err != nil {
		log.PrintE("can't set FD_CLOEXEC on rkt lock", err)
		return 254
	}

	workDir := "/"
	if ra.App.WorkingDirectory != "" {
		workDir = ra.App.WorkingDirectory
	}

	env := []string{"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"}
	for _, e := range ra.App.Environment {
		env = append(env, e.Name+"="+e.Value)
	}

	rfs := filepath.Join(common.AppPath(p.Root, ra.Name), "rootfs")

	argFlyMounts, err := evaluateMounts(rfs, string(ra.Name), p)
	if err != nil {
		log.PrintE("can't evaluate mounts", err)
		return 254
	}

	effectiveMounts := append(
		[]flyMount{
			{"", "", "/dev", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/dev", rfs, "/dev", "none", syscall.MS_BIND | syscall.MS_REC},

			{"", "", "/proc", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/proc", rfs, "/proc", "none", syscall.MS_BIND | syscall.MS_REC},

			{"", "", "/sys", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/sys", rfs, "/sys", "none", syscall.MS_BIND | syscall.MS_REC},

			{"tmpfs", rfs, "/tmp", "tmpfs", 0},
		},
		argFlyMounts...,
	)

	/* Process DNS config files
	 *
	 * /etc/resolv.conf: four modes
	 * 'host' - bind-mount host's file
	 * 'stage0' - bind-mount the file created by stage0
	 * 'default' - do nothing (we would respect CNI if fly had networking)
	 * 'none' - do nothing
	 */
	switch p.ResolvConfMode {
	case "host":
		effectiveMounts = append(effectiveMounts,
			flyMount{"/etc/resolv.conf", rfs, "/etc/resolv.conf", "none", syscall.MS_BIND | syscall.MS_RDONLY})
	case "stage0":
		if err := copyResolv(p); err != nil {
			log.PrintE("can't copy /etc/resolv.conf", err)
			return 254
		}
	}

	/*
	 * /etc/hosts: three modes:
//.........这里部分代码省略.........

func stage1() int {
	uuid, err := types.NewUUID(flag.Arg(0))
	if err != nil {
		log.Print("UUID is missing or malformed\n")
		return 1
	}

	root := "."
	p, err := stage1commontypes.LoadPod(root, uuid)
	if err != nil {
		log.PrintE("can't load pod", err)
		return 1
	}

	// Sanity checks
	if len(p.Manifest.Apps) != 1 {
		log.Printf("flavor %q only supports 1 application per Pod for now", flavor)
		return 1
	}

	ra := p.Manifest.Apps[0]

	imgName := p.AppNameToImageName(ra.Name)
	args := ra.App.Exec
	if len(args) == 0 {
		log.Printf(`image %q has an empty "exec" (try --exec=BINARY)`, imgName)
		return 1
	}

	lfd, err := common.GetRktLockFD()
	if err != nil {
		log.PrintE("can't get rkt lock fd", err)
		return 1
	}

	// set close-on-exec flag on RKT_LOCK_FD so it gets correctly closed after execution is finished
	if err := sys.CloseOnExec(lfd, true); err != nil {
		log.PrintE("can't set FD_CLOEXEC on rkt lock", err)
		return 1
	}

	workDir := "/"
	if ra.App.WorkingDirectory != "" {
		workDir = ra.App.WorkingDirectory
	}

	env := []string{"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"}
	for _, e := range ra.App.Environment {
		env = append(env, e.Name+"="+e.Value)
	}

	rfs := filepath.Join(common.AppPath(p.Root, ra.Name), "rootfs")

	if err := copyResolv(p); err != nil {
		log.PrintE("can't copy /etc/resolv.conf", err)
		return 1
	}

	argFlyMounts, err := evaluateMounts(rfs, string(ra.Name), p)
	if err != nil {
		log.PrintE("can't evaluate mounts", err)
		return 1
	}

	effectiveMounts := append(
		[]flyMount{
			{"", "", "/dev", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/dev", rfs, "/dev", "none", syscall.MS_BIND | syscall.MS_REC},

			{"", "", "/proc", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/proc", rfs, "/proc", "none", syscall.MS_BIND | syscall.MS_REC},

			{"", "", "/sys", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/sys", rfs, "/sys", "none", syscall.MS_BIND | syscall.MS_REC},

			{"tmpfs", rfs, "/tmp", "tmpfs", 0},
		},
		argFlyMounts...,
	)

	for _, mount := range effectiveMounts {
		var (
			err            error
			hostPathInfo   os.FileInfo
			targetPathInfo os.FileInfo
		)

		if strings.HasPrefix(mount.HostPath, "/") {
			if hostPathInfo, err = os.Stat(mount.HostPath); err != nil {
				log.PrintE(fmt.Sprintf("stat of host path %s", mount.HostPath), err)
				return 1
			}
		} else {
			hostPathInfo = nil
		}

		absTargetPath := filepath.Join(mount.TargetPrefixPath, mount.RelTargetPath)
		if targetPathInfo, err = os.Stat(absTargetPath); err != nil && !os.IsNotExist(err) {
			log.PrintE(fmt.Sprintf("stat of target path %s", absTargetPath), err)
			return 1
//.........这里部分代码省略.........

// prepareAppImage renders and verifies the tree cache of the app image that
// corresponds to the given app name.
// When useOverlay is false, it attempts to render and expand the app image
func prepareAppImage(cfg PrepareConfig, appName types.ACName, img types.Hash, cdir string, useOverlay bool) error {
	debug("Loading image %s", img.String())

	am, err := cfg.Store.GetImageManifest(img.String())
	if err != nil {
		return fmt.Errorf("error getting the manifest: %v", err)
	}

	if _, hasOS := am.Labels.Get("os"); !hasOS {
		return fmt.Errorf("missing os label in the image manifest")
	}
	if _, hasArch := am.Labels.Get("arch"); !hasArch {
		return fmt.Errorf("missing arch label in the image manifest")
	}

	if err := types.IsValidOSArch(am.Labels.ToMap(), ValidOSArch); err != nil {
		return err
	}

	appInfoDir := common.AppInfoPath(cdir, appName)
	if err := os.MkdirAll(appInfoDir, defaultRegularDirPerm); err != nil {
		return fmt.Errorf("error creating apps info directory: %v", err)
	}

	if useOverlay {
		if cfg.PrivateUsers.Shift > 0 {
			return fmt.Errorf("cannot use both overlay and user namespace: not implemented yet. (Try --no-overlay)")
		}
		treeStoreID, _, err := cfg.Store.RenderTreeStore(img.String(), false)
		if err != nil {
			return fmt.Errorf("error rendering tree image: %v", err)
		}

		if !cfg.SkipTreeStoreCheck {
			hash, err := cfg.Store.CheckTreeStore(treeStoreID)
			if err != nil {
				log.Printf("Warning: tree cache is in a bad state: %v. Rebuilding...", err)
				var err error
				treeStoreID, hash, err = cfg.Store.RenderTreeStore(img.String(), true)
				if err != nil {
					return fmt.Errorf("error rendering tree image: %v", err)
				}
			}
			cfg.CommonConfig.RootHash = hash
		}

		if err := ioutil.WriteFile(common.AppTreeStoreIDPath(cdir, appName), []byte(treeStoreID), defaultRegularFilePerm); err != nil {
			return fmt.Errorf("error writing app treeStoreID: %v", err)
		}
	} else {
		ad := common.AppPath(cdir, appName)
		err := os.MkdirAll(ad, defaultRegularDirPerm)
		if err != nil {
			return fmt.Errorf("error creating image directory: %v", err)
		}

		shiftedUid, shiftedGid, err := cfg.PrivateUsers.ShiftRange(uint32(os.Getuid()), uint32(os.Getgid()))
		if err != nil {
			return fmt.Errorf("error getting uid, gid: %v", err)
		}

		if err := os.Chown(ad, int(shiftedUid), int(shiftedGid)); err != nil {
			return fmt.Errorf("error shifting app %q's stage2 dir: %v", appName, err)
		}

		if err := aci.RenderACIWithImageID(img, ad, cfg.Store, cfg.PrivateUsers); err != nil {
			return fmt.Errorf("error rendering ACI: %v", err)
		}
	}
	if err := writeManifest(*cfg.CommonConfig, img, appInfoDir); err != nil {
		return err
	}
	return nil
}

func RmApp(cfg RmConfig) error {
	pod, err := pkgPod.PodFromUUIDString(cfg.DataDir, cfg.UUID.String())
	if err != nil {
		return errwrap.Wrap(errors.New("error loading pod"), err)
	}
	defer pod.Close()

	debug("locking sandbox manifest")
	if err := pod.ExclusiveLockManifest(); err != nil {
		return errwrap.Wrap(errors.New("failed to lock sandbox manifest"), err)
	}
	defer pod.UnlockManifest()

	pm, err := pod.SandboxManifest()
	if err != nil {
		return errwrap.Wrap(errors.New("cannot remove application, sandbox validation failed"), err)
	}

	app := pm.Apps.Get(*cfg.AppName)
	if app == nil {
		return fmt.Errorf("error: nonexistent app %q", *cfg.AppName)
	}

	if cfg.PodPID > 0 {
		// Call app-stop and app-rm entrypoint only if the pod is still running.
		// Otherwise, there's not much we can do about it except unmounting/removing
		// the file system.
		args := []string{
			fmt.Sprintf("--debug=%t", cfg.Debug),
			fmt.Sprintf("--app=%s", cfg.AppName),
		}

		ce := CrossingEntrypoint{
			PodPath:        cfg.PodPath,
			PodPID:         cfg.PodPID,
			AppName:        cfg.AppName.String(),
			EntrypointName: appStopEntrypoint,
			EntrypointArgs: args,
			Interactive:    false,
		}
		if err := ce.Run(); err != nil {
			status, err := common.GetExitStatus(err)
			// ignore nonexistent units failing to stop. Exit status 5
			// comes from systemctl and means the unit doesn't exist
			if err != nil {
				return err
			} else if status != 5 {
				return fmt.Errorf("exit status %d", status)
			}
		}

		ce.EntrypointName = appRmEntrypoint
		if err := ce.Run(); err != nil {
			return err
		}
	}

	if cfg.UsesOverlay {
		treeStoreID, err := ioutil.ReadFile(common.AppTreeStoreIDPath(cfg.PodPath, *cfg.AppName))
		if err != nil {
			return err
		}

		appRootfs := common.AppRootfsPath(cfg.PodPath, *cfg.AppName)
		if err := syscall.Unmount(appRootfs, 0); err != nil {
			return err
		}

		ts := filepath.Join(cfg.PodPath, "overlay", string(treeStoreID))
		if err := os.RemoveAll(ts); err != nil {
			return errwrap.Wrap(errors.New("error removing app info directory"), err)
		}
	}

	appInfoDir := common.AppInfoPath(cfg.PodPath, *cfg.AppName)
	if err := os.RemoveAll(appInfoDir); err != nil {
		return errwrap.Wrap(errors.New("error removing app info directory"), err)
	}

	if err := os.RemoveAll(common.AppPath(cfg.PodPath, *cfg.AppName)); err != nil {
		return err
	}

	appStatusPath := filepath.Join(common.Stage1RootfsPath(cfg.PodPath), "rkt", "status", cfg.AppName.String())
	if err := os.Remove(appStatusPath); err != nil && !os.IsNotExist(err) {
		return err
	}

	envPath := filepath.Join(common.Stage1RootfsPath(cfg.PodPath), "rkt", "env", cfg.AppName.String())
	if err := os.Remove(envPath); err != nil && !os.IsNotExist(err) {
		return err
	}

	for i, app := range pm.Apps {
		if app.Name == *cfg.AppName {
			pm.Apps = append(pm.Apps[:i], pm.Apps[i+1:]...)
			break
		}
	}

//.........这里部分代码省略.........

func RmApp(cfg RmConfig) error {
	pod, err := pkgPod.PodFromUUIDString(cfg.DataDir, cfg.UUID.String())
	if err != nil {
		return errwrap.Wrap(errors.New("error loading pod"), err)
	}
	defer pod.Close()

	debug("locking pod manifest")
	if err := pod.ExclusiveManifestLock(); err != nil {
		return errwrap.Wrap(errors.New("failed to lock pod manifest"), err)
	}
	defer pod.ManifestUnlock()

	_, pm, err := pod.PodManifest()
	if err != nil {
		return errwrap.Wrap(errors.New("error loading pod manifest"), err)
	}

	var mutable bool
	ms, ok := pm.Annotations.Get("coreos.com/rkt/stage1/mutable")
	if ok {
		mutable, err = strconv.ParseBool(ms)
		if err != nil {
			return errwrap.Wrap(errors.New("error parsing mutable annotation"), err)
		}
	}

	if !mutable {
		return errors.New("immutable pod: cannot remove application")
	}

	app := pm.Apps.Get(*cfg.AppName)
	if app == nil {
		return fmt.Errorf("error: nonexistent app %q", *cfg.AppName)
	}

	if cfg.PodPID > 0 {
		// Call app-stop and app-rm entrypoint only if the pod is still running.
		// Otherwise, there's not much we can do about it except unmounting/removing
		// the file system.
		args := []string{
			fmt.Sprintf("--app=%s", cfg.AppName),
		}

		ce := CrossingEntrypoint{
			PodPath:        cfg.PodPath,
			PodPID:         cfg.PodPID,
			AppName:        cfg.AppName.String(),
			EntrypointName: appStopEntrypoint,
			EntrypointArgs: args,
			Interactive:    false,
		}
		if err := ce.Run(); err != nil {
			status, err := common.GetExitStatus(err)
			// ignore nonexistent units failing to stop. Exit status 5
			// comes from systemctl and means the unit doesn't exist
			if err != nil {
				return err
			} else if status != 5 {
				return fmt.Errorf("exit status %d", status)
			}
		}

		ce.EntrypointName = appRmEntrypoint
		if err := ce.Run(); err != nil {
			return err
		}
	}

	if cfg.UsesOverlay {
		treeStoreID, err := ioutil.ReadFile(common.AppTreeStoreIDPath(cfg.PodPath, *cfg.AppName))
		if err != nil {
			return err
		}

		appRootfs := common.AppRootfsPath(cfg.PodPath, *cfg.AppName)
		if err := syscall.Unmount(appRootfs, 0); err != nil {
			return err
		}

		ts := filepath.Join(cfg.PodPath, "overlay", string(treeStoreID))
		if err := os.RemoveAll(ts); err != nil {
			return errwrap.Wrap(errors.New("error removing app info directory"), err)
		}
	}

	appInfoDir := common.AppInfoPath(cfg.PodPath, *cfg.AppName)
	if err := os.RemoveAll(appInfoDir); err != nil {
		return errwrap.Wrap(errors.New("error removing app info directory"), err)
	}

	if err := os.RemoveAll(common.AppPath(cfg.PodPath, *cfg.AppName)); err != nil {
		return err
	}

	appStatusPath := filepath.Join(common.Stage1RootfsPath(cfg.PodPath), "rkt", "status", cfg.AppName.String())
	if err := os.Remove(appStatusPath); err != nil && !os.IsNotExist(err) {
		return err
	}

//.........这里部分代码省略.........

func stage1() int {
	uuid, err := types.NewUUID(flag.Arg(0))
	if err != nil {
		log.Print("UUID is missing or malformed\n")
		return 1
	}

	root := "."
	p, err := stage1commontypes.LoadPod(root, uuid)
	if err != nil {
		log.PrintE("can't load pod", err)
		return 1
	}

	if len(p.Manifest.Apps) != 1 {
		log.Printf("flavor %q only supports 1 application per Pod for now", flavor)
		return 1
	}

	lfd, err := common.GetRktLockFD()
	if err != nil {
		log.PrintE("can't get rkt lock fd", err)
		return 1
	}

	// set close-on-exec flag on RKT_LOCK_FD so it gets correctly closed after execution is finished
	if err := sys.CloseOnExec(lfd, true); err != nil {
		log.PrintE("can't set FD_CLOEXEC on rkt lock", err)
		return 1
	}

	env := []string{"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"}
	for _, e := range p.Manifest.Apps[0].App.Environment {
		env = append(env, e.Name+"="+e.Value)
	}

	args := p.Manifest.Apps[0].App.Exec
	rfs := filepath.Join(common.AppPath(p.Root, p.Manifest.Apps[0].Name), "rootfs")

	argFlyMounts, err := evaluateMounts(rfs, string(p.Manifest.Apps[0].Name), p)
	if err != nil {
		log.PrintE("can't evaluate mounts", err)
		return 1
	}

	effectiveMounts := append(
		[]flyMount{
			{"", "", "/dev", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/dev", rfs, "/dev", "none", syscall.MS_BIND | syscall.MS_REC},

			{"", "", "/proc", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/proc", rfs, "/proc", "none", syscall.MS_BIND | syscall.MS_REC},

			{"", "", "/sys", "none", syscall.MS_REC | syscall.MS_SHARED},
			{"/sys", rfs, "/sys", "none", syscall.MS_BIND | syscall.MS_REC},

			{"tmpfs", rfs, "/tmp", "tmpfs", 0},
		},
		argFlyMounts...,
	)

	for _, mount := range effectiveMounts {
		var (
			err            error
			hostPathInfo   os.FileInfo
			targetPathInfo os.FileInfo
		)

		if strings.HasPrefix(mount.HostPath, "/") {
			if hostPathInfo, err = os.Stat(mount.HostPath); err != nil {
				log.PrintE(fmt.Sprintf("stat of host directory %s", mount.HostPath), err)
				return 1
			}
		} else {
			hostPathInfo = nil
		}

		absTargetPath := filepath.Join(mount.TargetPrefixPath, mount.RelTargetPath)
		if targetPathInfo, err = os.Stat(absTargetPath); err != nil && !os.IsNotExist(err) {
			log.PrintE(fmt.Sprintf("stat of target directory %s", absTargetPath), err)
			return 1
		}

		switch {
		case targetPathInfo == nil:
			absTargetPathParent, _ := filepath.Split(absTargetPath)
			if err := os.MkdirAll(absTargetPathParent, 0700); err != nil {
				log.PrintE(fmt.Sprintf("can't create directory %q", absTargetPath), err)
				return 1
			}
			switch {
			case hostPathInfo == nil || hostPathInfo.IsDir():
				if err := os.Mkdir(absTargetPath, 0700); err != nil {
					log.PrintE(fmt.Sprintf("can't create directory %q", absTargetPath), err)
					return 1
				}
			case !hostPathInfo.IsDir():
				file, err := os.OpenFile(absTargetPath, os.O_CREATE, 0700)
				if err != nil {
					log.PrintE(fmt.Sprintf("can't create file %q", absTargetPath), err)
//.........这里部分代码省略.........

func runExport(cmd *cobra.Command, args []string) (exit int) {
	if len(args) != 2 {
		cmd.Usage()
		return 1
	}

	outACI := args[1]
	ext := filepath.Ext(outACI)
	if ext != schema.ACIExtension {
		stderr.Printf("extension must be %s (given %s)", schema.ACIExtension, outACI)
		return 1
	}

	p, err := getPodFromUUIDString(args[0])
	if err != nil {
		stderr.PrintE("problem retrieving pod", err)
		return 1
	}
	defer p.Close()

	if !p.isExited {
		stderr.Print("pod is not exited. Only exited pods can be exported")
		return 1
	}

	app, err := getApp(p)
	if err != nil {
		stderr.PrintE("unable to find app", err)
		return 1
	}

	root := common.AppPath(p.path(), app.Name)
	manifestPath := filepath.Join(common.AppInfoPath(p.path(), app.Name), aci.ManifestFile)
	if p.usesOverlay() {
		tmpDir := filepath.Join(getDataDir(), "tmp")
		if err := os.MkdirAll(tmpDir, common.DefaultRegularDirPerm); err != nil {
			stderr.PrintE("unable to create temp directory", err)
			return 1
		}
		podDir, err := ioutil.TempDir(tmpDir, fmt.Sprintf("rkt-export-%s", p.uuid))
		if err != nil {
			stderr.PrintE("unable to create export temp directory", err)
			return 1
		}
		defer func() {
			if err := os.RemoveAll(podDir); err != nil {
				stderr.PrintE("problem removing temp directory", err)
				exit = 1
			}
		}()
		mntDir := filepath.Join(podDir, "rootfs")
		if err := os.Mkdir(mntDir, common.DefaultRegularDirPerm); err != nil {
			stderr.PrintE("unable to create rootfs directory inside temp directory", err)
			return 1
		}

		if err := mountOverlay(p, app, mntDir); err != nil {
			stderr.PrintE(fmt.Sprintf("couldn't mount directory at %s", mntDir), err)
			return 1
		}
		defer func() {
			if err := syscall.Unmount(mntDir, 0); err != nil {
				stderr.PrintE(fmt.Sprintf("error unmounting directory %s", mntDir), err)
				exit = 1
			}
		}()
		root = podDir
	} else {
		hasMPs, err := appHasMountpoints(p.path(), app.Name)
		if err != nil {
			stderr.PrintE("error parsing mountpoints", err)
			return 1
		}
		if hasMPs {
			stderr.Printf("pod has remaining mountpoints. Only pods using overlayfs or with no mountpoints can be exported")
			return 1
		}
	}

	// Check for user namespace (--private-user), if in use get uidRange
	var uidRange *user.UidRange
	privUserFile := filepath.Join(p.path(), common.PrivateUsersPreparedFilename)
	privUserContent, err := ioutil.ReadFile(privUserFile)
	if err == nil {
		uidRange = user.NewBlankUidRange()
		// The file was found, save uid & gid shift and count
		if err := uidRange.Deserialize(privUserContent); err != nil {
			stderr.PrintE(fmt.Sprintf("problem deserializing the content of %s", common.PrivateUsersPreparedFilename), err)
			return 1
		}
	}

	if err = buildAci(root, manifestPath, outACI, uidRange); err != nil {
		stderr.PrintE("error building aci", err)
		return 1
	}
	return 0
}

// TODO(iaguis): RmConfig?
func RmApp(dir string, uuid *types.UUID, usesOverlay bool, appName *types.ACName, podPID int) error {
	p, err := stage1types.LoadPod(dir, uuid)
	if err != nil {
		return errwrap.Wrap(errors.New("error loading pod manifest"), err)
	}

	pm := p.Manifest

	var mutable bool
	ms, ok := pm.Annotations.Get("coreos.com/rkt/stage1/mutable")
	if ok {
		mutable, err = strconv.ParseBool(ms)
		if err != nil {
			return errwrap.Wrap(errors.New("error parsing mutable annotation"), err)
		}
	}

	if !mutable {
		return errors.New("immutable pod: cannot remove application")
	}

	app := pm.Apps.Get(*appName)
	if app == nil {
		return fmt.Errorf("error: nonexistent app %q", *appName)
	}

	treeStoreID, err := ioutil.ReadFile(common.AppTreeStoreIDPath(dir, *appName))
	if err != nil {
		return err
	}

	eep, err := getStage1Entrypoint(dir, enterEntrypoint)
	if err != nil {
		return errwrap.Wrap(errors.New("error determining 'enter' entrypoint"), err)
	}

	args := []string{
		uuid.String(),
		appName.String(),
		filepath.Join(common.Stage1RootfsPath(dir), eep),
		strconv.Itoa(podPID),
	}

	if err := callEntrypoint(dir, appStopEntrypoint, args); err != nil {
		return err
	}

	if err := callEntrypoint(dir, appRmEntrypoint, args); err != nil {
		return err
	}

	appInfoDir := common.AppInfoPath(dir, *appName)
	if err := os.RemoveAll(appInfoDir); err != nil {
		return errwrap.Wrap(errors.New("error removing app info directory"), err)
	}

	if usesOverlay {
		appRootfs := common.AppRootfsPath(dir, *appName)
		if err := syscall.Unmount(appRootfs, 0); err != nil {
			return err
		}

		ts := filepath.Join(dir, "overlay", string(treeStoreID))
		if err := os.RemoveAll(ts); err != nil {
			return errwrap.Wrap(errors.New("error removing app info directory"), err)
		}
	}

	if err := os.RemoveAll(common.AppPath(dir, *appName)); err != nil {
		return err
	}

	appStatusPath := filepath.Join(common.Stage1RootfsPath(dir), "rkt", "status", appName.String())
	if err := os.Remove(appStatusPath); err != nil && !os.IsNotExist(err) {
		return err
	}

	envPath := filepath.Join(common.Stage1RootfsPath(dir), "rkt", "env", appName.String())
	if err := os.Remove(envPath); err != nil && !os.IsNotExist(err) {
		return err
	}

	removeAppFromPodManifest(pm, appName)

	if err := updatePodManifest(dir, pm); err != nil {
		return err
	}

	return nil
}

// emptyExitedGarbage discards sufficiently aged pods from exitedGarbageDir()
func emptyExitedGarbage(gracePeriod time.Duration) error {
	if err := walkPods(includeExitedGarbageDir, func(p *pod) {
		gp := p.path()
		st := &syscall.Stat_t{}
		if err := syscall.Lstat(gp, st); err != nil {
			if err != syscall.ENOENT {
				stderr("Unable to stat %q, ignoring: %v", gp, err)
			}
			return
		}

		if expiration := time.Unix(st.Ctim.Unix()).Add(gracePeriod); time.Now().After(expiration) {
			if err := p.ExclusiveLock(); err != nil {
				return
			}
			stdout("Garbage collecting pod %q", p.uuid)

			s, err := store.NewStore(globalFlags.Dir)
			if err != nil {
				stderr("Cannot open store: %v", err)
				return
			}
			stage1ID, err := p.getStage1Hash()
			if err != nil {
				stderr("Error getting stage1 hash")
				return
			}
			stage1RootFS := s.GetTreeStoreRootFS(stage1ID.String())

			// execute stage1's GC
			if err := stage0.GC(p.path(), p.uuid, stage1RootFS, globalFlags.Debug); err != nil {
				stderr("Stage1 GC of pod %q failed: %v", p.uuid, err)
				return
			}

			if p.usesOverlay() {
				apps, err := p.getApps()
				if err != nil {
					stderr("Error retrieving app list from pod manifest: %v", err)
					return
				}
				for _, a := range apps {
					dest := filepath.Join(common.AppPath(p.path(), a.Name), "rootfs")
					if err := syscall.Unmount(dest, 0); err != nil {
						// machine could have been rebooted and mounts lost.
						// ignore "does not exist" and "not a mount point" errors
						if err != syscall.ENOENT && err != syscall.EINVAL {
							stderr("Error unmounting app at %v: %v", dest, err)
						}
					}
				}

				s1 := filepath.Join(common.Stage1ImagePath(p.path()), "rootfs")
				if err := syscall.Unmount(s1, 0); err != nil {
					// machine could have been rebooted and mounts lost.
					// ignore "does not exist" and "not a mount point" errors
					if err != syscall.ENOENT && err != syscall.EINVAL {
						stderr("Error unmounting stage1 at %v: %v", s1, err)
						return
					}
				}
			}

			if err := os.RemoveAll(gp); err != nil {
				stderr("Unable to remove pod %q: %v", p.uuid, err)
			}
		}
	}); err != nil {
		return err
	}

	return nil
}

// TODO(iaguis): add override options for Exec, Environment (à la patch-manifest)
func AddApp(cfg RunConfig, dir string, img *types.Hash) error {
	im, err := cfg.Store.GetImageManifest(img.String())
	if err != nil {
		return err
	}
	appName, err := imageNameToAppName(im.Name)
	if err != nil {
		return err
	}

	p, err := stage1types.LoadPod(dir, cfg.UUID)
	if err != nil {
		return errwrap.Wrap(errors.New("error loading pod manifest"), err)
	}

	pm := p.Manifest

	var mutable bool
	ms, ok := pm.Annotations.Get("coreos.com/rkt/stage1/mutable")
	if ok {
		mutable, err = strconv.ParseBool(ms)
		if err != nil {
			return errwrap.Wrap(errors.New("error parsing mutable annotation"), err)
		}
	}

	if !mutable {
		return errors.New("immutable pod: cannot add application")
	}

	if pm.Apps.Get(*appName) != nil {
		return fmt.Errorf("error: multiple apps with name %s", *appName)
	}
	if im.App == nil {
		return fmt.Errorf("error: image %s has no app section)", img)
	}

	appInfoDir := common.AppInfoPath(dir, *appName)
	if err := os.MkdirAll(appInfoDir, common.DefaultRegularDirPerm); err != nil {
		return errwrap.Wrap(errors.New("error creating apps info directory"), err)
	}

	uidRange := user.NewBlankUidRange()
	// TODO(iaguis): DRY: refactor this
	var treeStoreID string
	if cfg.UseOverlay {
		treeStoreID, _, err := cfg.TreeStore.Render(img.String(), false)
		if err != nil {
			return errwrap.Wrap(errors.New("error rendering tree image"), err)
		}

		hash, err := cfg.TreeStore.Check(treeStoreID)
		if err != nil {
			log.PrintE("warning: tree cache is in a bad state.  Rebuilding...", err)
			var err error
			treeStoreID, hash, err = cfg.TreeStore.Render(img.String(), true)
			if err != nil {
				return errwrap.Wrap(errors.New("error rendering tree image"), err)
			}
		}
		cfg.RootHash = hash

		if err := ioutil.WriteFile(common.AppTreeStoreIDPath(dir, *appName), []byte(treeStoreID), common.DefaultRegularFilePerm); err != nil {
			return errwrap.Wrap(errors.New("error writing app treeStoreID"), err)
		}
	} else {
		ad := common.AppPath(dir, *appName)

		err := os.MkdirAll(ad, common.DefaultRegularDirPerm)
		if err != nil {
			return errwrap.Wrap(errors.New("error creating image directory"), err)
		}

		privateUsers, err := preparedWithPrivateUsers(dir)
		if err != nil {
			log.FatalE("error reading user namespace information", err)
		}

		if err := uidRange.Deserialize([]byte(privateUsers)); err != nil {
			return err
		}

		shiftedUid, shiftedGid, err := uidRange.ShiftRange(uint32(os.Getuid()), uint32(os.Getgid()))
		if err != nil {
			return errwrap.Wrap(errors.New("error getting uid, gid"), err)
		}

		if err := os.Chown(ad, int(shiftedUid), int(shiftedGid)); err != nil {
			return errwrap.Wrap(fmt.Errorf("error shifting app %q's stage2 dir", *appName), err)
		}

		if err := aci.RenderACIWithImageID(*img, ad, cfg.Store, uidRange); err != nil {
			return errwrap.Wrap(errors.New("error rendering ACI"), err)
		}
	}

	if err := writeManifest(*cfg.CommonConfig, *img, appInfoDir); err != nil {
		return errwrap.Wrap(errors.New("error writing manifest"), err)
	}
//.........这里部分代码省略.........