// getExecConfig looks up the exec instance by name. If the container associated
// with the exec instance is stopped or paused, it will return an error.
func (d *Daemon) getExecConfig(name string) (*exec.Config, error) {
	ec := d.execCommands.Get(name)

	// If the exec is found but its container is not in the daemon's list of
	// containers then it must have been deleted, in which case instead of
	// saying the container isn't running, we should return a 404 so that
	// the user sees the same error now that they will after the
	// 5 minute clean-up loop is run which erases old/dead execs.

	if ec != nil {
		if container := d.containers.Get(ec.ContainerID); container != nil {
			if !container.IsRunning() {
				return nil, fmt.Errorf("Container %s is not running: %s", container.ID, container.State.String())
			}
			if container.IsPaused() {
				return nil, errExecPaused(container.ID)
			}
			if container.IsRestarting() {
				return nil, errContainerIsRestarting(container.ID)
			}
			return ec, nil
		}
	}

	return nil, errExecNotFound(name)
}

// ContainerStart starts a container.
func (daemon *Daemon) ContainerStart(name string, hostConfig *containertypes.HostConfig) error {
	container, err := daemon.GetContainer(name)
	if err != nil {
		return err
	}

	if container.IsPaused() {
		return fmt.Errorf("Cannot start a paused container, try unpause instead.")
	}

	if container.IsRunning() {
		err := fmt.Errorf("Container already started")
		return errors.NewErrorWithStatusCode(err, http.StatusNotModified)
	}

	// Windows does not have the backwards compatibility issue here.
	if runtime.GOOS != "windows" {
		// This is kept for backward compatibility - hostconfig should be passed when
		// creating a container, not during start.
		if hostConfig != nil {
			logrus.Warn("DEPRECATED: Setting host configuration options when the container starts is deprecated and will be removed in Docker 1.12")
			oldNetworkMode := container.HostConfig.NetworkMode
			if err := daemon.setSecurityOptions(container, hostConfig); err != nil {
				return err
			}
			if err := daemon.setHostConfig(container, hostConfig); err != nil {
				return err
			}
			newNetworkMode := container.HostConfig.NetworkMode
			if string(oldNetworkMode) != string(newNetworkMode) {
				// if user has change the network mode on starting, clean up the
				// old networks. It is a deprecated feature and will be removed in Docker 1.12
				container.NetworkSettings.Networks = nil
				if err := container.ToDisk(); err != nil {
					return err
				}
			}
			container.InitDNSHostConfig()
		}
	} else {
		if hostConfig != nil {
			return fmt.Errorf("Supplying a hostconfig on start is not supported. It should be supplied on create")
		}
	}

	// check if hostConfig is in line with the current system settings.
	// It may happen cgroups are umounted or the like.
	if _, err = daemon.verifyContainerSettings(container.HostConfig, nil, false); err != nil {
		return err
	}
	// Adapt for old containers in case we have updates in this function and
	// old containers never have chance to call the new function in create stage.
	if err := daemon.adaptContainerSettings(container.HostConfig, false); err != nil {
		return err
	}

	return daemon.containerStart(container)
}

// ContainerAttachWithLogs attaches to logs according to the config passed in. See ContainerAttachWithLogsConfig.
func (daemon *Daemon) ContainerAttachWithLogs(prefixOrName string, c *ContainerAttachWithLogsConfig) error {
	if c.Hijacker == nil {
		return derr.ErrorCodeNoHijackConnection.WithArgs(prefixOrName)
	}
	container, err := daemon.GetContainer(prefixOrName)
	if err != nil {
		return derr.ErrorCodeNoSuchContainer.WithArgs(prefixOrName)
	}
	if container.IsPaused() {
		return derr.ErrorCodePausedContainer.WithArgs(prefixOrName)
	}

	conn, _, err := c.Hijacker.Hijack()
	if err != nil {
		return err
	}
	defer conn.Close()
	// Flush the options to make sure the client sets the raw mode
	conn.Write([]byte{})
	inStream := conn.(io.ReadCloser)
	outStream := conn.(io.Writer)

	if c.Upgrade {
		fmt.Fprintf(outStream, "HTTP/1.1 101 UPGRADED\r\nContent-Type: application/vnd.docker.raw-stream\r\nConnection: Upgrade\r\nUpgrade: tcp\r\n\r\n")
	} else {
		fmt.Fprintf(outStream, "HTTP/1.1 200 OK\r\nContent-Type: application/vnd.docker.raw-stream\r\n\r\n")
	}

	var errStream io.Writer

	if !container.Config.Tty {
		errStream = stdcopy.NewStdWriter(outStream, stdcopy.Stderr)
		outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout)
	} else {
		errStream = outStream
	}

	var stdin io.ReadCloser
	var stdout, stderr io.Writer

	if c.UseStdin {
		stdin = inStream
	}
	if c.UseStdout {
		stdout = outStream
	}
	if c.UseStderr {
		stderr = errStream
	}

	if err := daemon.attachWithLogs(container, stdin, stdout, stderr, c.Logs, c.Stream, c.DetachKeys); err != nil {
		fmt.Fprintf(outStream, "Error attaching: %s\n", err)
	}
	return nil
}

// ContainerStart starts a container.
func (daemon *Daemon) ContainerStart(name string, hostConfig *runconfig.HostConfig) error {
	container, err := daemon.Get(name)
	if err != nil {
		return err
	}

	if container.IsPaused() {
		return derr.ErrorCodeStartPaused
	}

	if container.IsRunning() {
		return derr.ErrorCodeAlreadyStarted
	}

	// Windows does not have the backwards compatibility issue here.
	if runtime.GOOS != "windows" {
		// This is kept for backward compatibility - hostconfig should be passed when
		// creating a container, not during start.
		if hostConfig != nil {
			logrus.Warn("DEPRECATED: Setting host configuration options when the container starts is deprecated and will be removed in Docker 1.12")
			container.Lock()
			if err := parseSecurityOpt(container, hostConfig); err != nil {
				container.Unlock()
				return err
			}
			container.Unlock()
			if err := daemon.adaptContainerSettings(hostConfig, false); err != nil {
				return err
			}
			if err := daemon.setHostConfig(container, hostConfig); err != nil {
				return err
			}
			container.InitDNSHostConfig()
		}
	} else {
		if hostConfig != nil {
			return derr.ErrorCodeHostConfigStart
		}
	}

	// check if hostConfig is in line with the current system settings.
	// It may happen cgroups are umounted or the like.
	if _, err = daemon.verifyContainerSettings(container.HostConfig, nil); err != nil {
		return err
	}

	if err := daemon.containerStart(container); err != nil {
		return err
	}

	return nil
}

func (d *Daemon) getActiveContainer(name string) (*container.Container, error) {
	container, err := d.GetContainer(name)
	if err != nil {
		return nil, err
	}

	if !container.IsRunning() {
		return nil, derr.ErrorCodeNotRunning.WithArgs(name)
	}
	if container.IsPaused() {
		return nil, derr.ErrorCodeExecPaused.WithArgs(name)
	}
	return container, nil
}

// ContainerAttach attaches to logs according to the config passed in. See ContainerAttachConfig.
func (daemon *Daemon) ContainerAttach(prefixOrName string, c *backend.ContainerAttachConfig) error {
	keys := []byte{}
	var err error
	if c.DetachKeys != "" {
		keys, err = term.ToBytes(c.DetachKeys)
		if err != nil {
			return fmt.Errorf("Invalid escape keys (%s) provided", c.DetachKeys)
		}
	}

	container, err := daemon.GetContainer(prefixOrName)
	if err != nil {
		return err
	}
	if container.IsPaused() {
		err := fmt.Errorf("Container %s is paused. Unpause the container before attach", prefixOrName)
		return errors.NewRequestConflictError(err)
	}

	inStream, outStream, errStream, err := c.GetStreams()
	if err != nil {
		return err
	}
	defer inStream.Close()

	if !container.Config.Tty && c.MuxStreams {
		errStream = stdcopy.NewStdWriter(errStream, stdcopy.Stderr)
		outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout)
	}

	var stdin io.ReadCloser
	var stdout, stderr io.Writer

	if c.UseStdin {
		stdin = inStream
	}
	if c.UseStdout {
		stdout = outStream
	}
	if c.UseStderr {
		stderr = errStream
	}

	if err := daemon.containerAttach(container, stdin, stdout, stderr, c.Logs, c.Stream, keys); err != nil {
		fmt.Fprintf(outStream, "Error attaching: %s\n", err)
	}
	return nil
}

func (d *Daemon) getActiveContainer(name string) (*container.Container, error) {
	container, err := d.GetContainer(name)
	if err != nil {
		return nil, err
	}

	if !container.IsRunning() {
		return nil, errNotRunning{container.ID}
	}
	if container.IsPaused() {
		return nil, errExecPaused(name)
	}
	if container.IsRestarting() {
		return nil, errContainerIsRestarting(container.ID)
	}
	return container, nil
}

// ContainerAttach attaches to logs according to the config passed in. See ContainerAttachConfig.
func (daemon *Daemon) ContainerAttach(prefixOrName string, c *backend.ContainerAttachConfig) error {
	container, err := daemon.GetContainer(prefixOrName)
	if err != nil {
		return derr.ErrorCodeNoSuchContainer.WithArgs(prefixOrName)
	}
	if container.IsPaused() {
		return derr.ErrorCodePausedContainer.WithArgs(prefixOrName)
	}

	inStream, outStream, errStream, err := c.GetStreams()
	if err != nil {
		return err
	}
	defer inStream.Close()

	if !container.Config.Tty && c.MuxStreams {
		errStream = stdcopy.NewStdWriter(errStream, stdcopy.Stderr)
		outStream = stdcopy.NewStdWriter(outStream, stdcopy.Stdout)
	}

	var stdin io.ReadCloser
	var stdout, stderr io.Writer

	if c.UseStdin {
		stdin = inStream
	}
	if c.UseStdout {
		stdout = outStream
	}
	if c.UseStderr {
		stderr = errStream
	}

	if err := daemon.containerAttach(container, stdin, stdout, stderr, c.Logs, c.Stream, c.DetachKeys); err != nil {
		fmt.Fprintf(outStream, "Error attaching: %s\n", err)
	}
	return nil
}

// Commit creates a new filesystem image from the current state of a container.
// The image can optionally be tagged into a repository.
func (daemon *Daemon) Commit(name string, c *backend.ContainerCommitConfig) (string, error) {
	container, err := daemon.GetContainer(name)
	if err != nil {
		return "", err
	}

	// It is not possible to commit a running container on Windows
	if runtime.GOOS == "windows" && container.IsRunning() {
		return "", fmt.Errorf("Windows does not support commit of a running container")
	}

	if c.Pause && !container.IsPaused() {
		daemon.containerPause(container)
		defer daemon.containerUnpause(container)
	}

	newConfig, err := dockerfile.BuildFromConfig(c.Config, c.Changes)
	if err != nil {
		return "", err
	}

	if c.MergeConfigs {
		if err := merge(newConfig, container.Config); err != nil {
			return "", err
		}
	}

	rwTar, err := daemon.exportContainerRw(container)
	if err != nil {
		return "", err
	}
	defer func() {
		if rwTar != nil {
			rwTar.Close()
		}
	}()

	var history []image.History
	rootFS := image.NewRootFS()
	osVersion := ""
	var osFeatures []string

	if container.ImageID != "" {
		img, err := daemon.imageStore.Get(container.ImageID)
		if err != nil {
			return "", err
		}
		history = img.History
		rootFS = img.RootFS
		osVersion = img.OSVersion
		osFeatures = img.OSFeatures
	}

	l, err := daemon.layerStore.Register(rwTar, rootFS.ChainID())
	if err != nil {
		return "", err
	}
	defer layer.ReleaseAndLog(daemon.layerStore, l)

	h := image.History{
		Author:     c.Author,
		Created:    time.Now().UTC(),
		CreatedBy:  strings.Join(container.Config.Cmd, " "),
		Comment:    c.Comment,
		EmptyLayer: true,
	}

	if diffID := l.DiffID(); layer.DigestSHA256EmptyTar != diffID {
		h.EmptyLayer = false
		rootFS.Append(diffID)
	}

	history = append(history, h)

	config, err := json.Marshal(&image.Image{
		V1Image: image.V1Image{
			DockerVersion:   dockerversion.Version,
			Config:          newConfig,
			Architecture:    runtime.GOARCH,
			OS:              runtime.GOOS,
			Container:       container.ID,
			ContainerConfig: *container.Config,
			Author:          c.Author,
			Created:         h.Created,
		},
		RootFS:     rootFS,
		History:    history,
		OSFeatures: osFeatures,
		OSVersion:  osVersion,
	})

	if err != nil {
		return "", err
	}

	id, err := daemon.imageStore.Create(config)
	if err != nil {
		return "", err
//.........这里部分代码省略.........