package daemon import ( "io" "strings" "time" "github.com/Sirupsen/logrus" "github.com/docker/docker/api/types" "github.com/docker/docker/api/types/strslice" "github.com/docker/docker/container" "github.com/docker/docker/daemon/exec" "github.com/docker/docker/daemon/execdriver" derr "github.com/docker/docker/errors" "github.com/docker/docker/pkg/pools" "github.com/docker/docker/pkg/promise" ) func (d *Daemon) registerExecCommand(container *container.Container, config *exec.Config) { // Storing execs in container in order to kill them gracefully whenever the container is stopped or removed. container.ExecCommands.Add(config.ID, config) // Storing execs in daemon for easy access via remote API. d.execCommands.Add(config.ID, config) } // ExecExists looks up the exec instance and returns a bool if it exists or not. // It will also return the error produced by `getConfig` func (d *Daemon) ExecExists(name string) (bool, error) { if _, err := d.getExecConfig(name); err != nil { return false, err } return true, nil } // 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, derr.ErrorCodeContainerNotRunning.WithArgs(container.ID, container.State.String()) } if container.IsPaused() { return nil, derr.ErrorCodeExecPaused.WithArgs(container.ID) } return ec, nil } } return nil, derr.ErrorCodeNoExecID.WithArgs(name) } func (d *Daemon) unregisterExecCommand(container *container.Container, execConfig *exec.Config) { container.ExecCommands.Delete(execConfig.ID) d.execCommands.Delete(execConfig.ID) } 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 } // ContainerExecCreate sets up an exec in a running container. func (d *Daemon) ContainerExecCreate(config *types.ExecConfig) (string, error) { container, err := d.getActiveContainer(config.Container) if err != nil { return "", err } cmd := strslice.New(config.Cmd...) entrypoint, args := d.getEntrypointAndArgs(strslice.New(), cmd) processConfig := &execdriver.ProcessConfig{ CommonProcessConfig: execdriver.CommonProcessConfig{ Tty: config.Tty, Entrypoint: entrypoint, Arguments: args, }, } setPlatformSpecificExecProcessConfig(config, container, processConfig) execConfig := exec.NewConfig() execConfig.OpenStdin = config.AttachStdin execConfig.OpenStdout = config.AttachStdout execConfig.OpenStderr = config.AttachStderr execConfig.ProcessConfig = processConfig execConfig.ContainerID = container.ID d.registerExecCommand(container, execConfig) d.LogContainerEvent(container, "exec_create: "+execConfig.ProcessConfig.Entrypoint+" "+strings.Join(execConfig.ProcessConfig.Arguments, " ")) return execConfig.ID, nil } // ContainerExecStart starts a previously set up exec instance. The // std streams are set up. func (d *Daemon) ContainerExecStart(name string, stdin io.ReadCloser, stdout io.Writer, stderr io.Writer) error { var ( cStdin io.ReadCloser cStdout, cStderr io.Writer ) ec, err := d.getExecConfig(name) if err != nil { return derr.ErrorCodeNoExecID.WithArgs(name) } ec.Lock() if ec.Running { ec.Unlock() return derr.ErrorCodeExecRunning.WithArgs(ec.ID) } ec.Running = true ec.Unlock() c := d.containers.Get(ec.ContainerID) logrus.Debugf("starting exec command %s in container %s", ec.ID, c.ID) d.LogContainerEvent(c, "exec_start: "+ec.ProcessConfig.Entrypoint+" "+strings.Join(ec.ProcessConfig.Arguments, " ")) if ec.OpenStdin { r, w := io.Pipe() go func() { defer w.Close() defer logrus.Debugf("Closing buffered stdin pipe") pools.Copy(w, stdin) }() cStdin = r } if ec.OpenStdout { cStdout = stdout } if ec.OpenStderr { cStderr = stderr } if ec.OpenStdin { ec.NewInputPipes() } else { ec.NewNopInputPipe() } attachErr := container.AttachStreams(ec.StreamConfig, ec.OpenStdin, true, ec.ProcessConfig.Tty, cStdin, cStdout, cStderr) execErr := make(chan error) // Note, the ExecConfig data will be removed when the container // itself is deleted. This allows us to query it (for things like // the exitStatus) even after the cmd is done running. go func() { execErr <- d.containerExec(c, ec) }() select { case err := <-attachErr: if err != nil { return derr.ErrorCodeExecAttach.WithArgs(err) } return nil case err := <-execErr: if aErr := <-attachErr; aErr != nil && err == nil { return derr.ErrorCodeExecAttach.WithArgs(aErr) } if err == nil { return nil } // Maybe the container stopped while we were trying to exec if !c.IsRunning() { return derr.ErrorCodeExecContainerStopped } return derr.ErrorCodeExecCantRun.WithArgs(ec.ID, c.ID, err) } } // Exec calls the underlying exec driver to run func (d *Daemon) Exec(c *container.Container, execConfig *exec.Config, pipes *execdriver.Pipes, startCallback execdriver.DriverCallback) (int, error) { hooks := execdriver.Hooks{ Start: startCallback, } exitStatus, err := d.execDriver.Exec(c.Command, execConfig.ProcessConfig, pipes, hooks) // On err, make sure we don't leave ExitCode at zero if err != nil && exitStatus == 0 { exitStatus = 128 } execConfig.ExitCode = exitStatus execConfig.Running = false return exitStatus, err } // execCommandGC runs a ticker to clean up the daemon references // of exec configs that are no longer part of the container. func (d *Daemon) execCommandGC() { for range time.Tick(5 * time.Minute) { var ( cleaned int liveExecCommands = d.containerExecIds() ) for id, config := range d.execCommands.Commands() { if config.CanRemove { cleaned++ d.execCommands.Delete(id) } else { if _, exists := liveExecCommands[id]; !exists { config.CanRemove = true } } } if cleaned > 0 { logrus.Debugf("clean %d unused exec commands", cleaned) } } } // containerExecIds returns a list of all the current exec ids that are in use // and running inside a container. func (d *Daemon) containerExecIds() map[string]struct{} { ids := map[string]struct{}{} for _, c := range d.containers.List() { for _, id := range c.ExecCommands.List() { ids[id] = struct{}{} } } return ids } func (d *Daemon) containerExec(container *container.Container, ec *exec.Config) error { container.Lock() defer container.Unlock() callback := func(processConfig *execdriver.ProcessConfig, pid int, chOOM <-chan struct{}) error { if processConfig.Tty { // The callback is called after the process Start() // so we are in the parent process. In TTY mode, stdin/out/err is the PtySlave // which we close here. if c, ok := processConfig.Stdout.(io.Closer); ok { c.Close() } } ec.Close() return nil } // We use a callback here instead of a goroutine and an chan for // synchronization purposes cErr := promise.Go(func() error { return d.monitorExec(container, ec, callback) }) return ec.Wait(cErr) } func (d *Daemon) monitorExec(container *container.Container, execConfig *exec.Config, callback execdriver.DriverCallback) error { pipes := execdriver.NewPipes(execConfig.Stdin(), execConfig.Stdout(), execConfig.Stderr(), execConfig.OpenStdin) exitCode, err := d.Exec(container, execConfig, pipes, callback) if err != nil { logrus.Errorf("Error running command in existing container %s: %s", container.ID, err) } logrus.Debugf("Exec task in container %s exited with code %d", container.ID, exitCode) if err := execConfig.CloseStreams(); err != nil { logrus.Errorf("%s: %s", container.ID, err) } if execConfig.ProcessConfig.Terminal != nil { if err := execConfig.ProcessConfig.Terminal.Close(); err != nil { logrus.Errorf("Error closing terminal while running in container %s: %s", container.ID, err) } } // remove the exec command from the container's store only and not the // daemon's store so that the exec command can be inspected. container.ExecCommands.Delete(execConfig.ID) return err }