package libcontainerd import ( "fmt" "io" "io/ioutil" "strings" "syscall" "time" "github.com/Microsoft/hcsshim" "github.com/Sirupsen/logrus" "github.com/opencontainers/runtime-spec/specs-go" ) type container struct { containerCommon // Platform specific fields are below here. There are none presently on Windows. options []CreateOption // The ociSpec is required, as client.Create() needs a spec, // but can be called from the RestartManager context which does not // otherwise have access to the Spec ociSpec specs.Spec manualStopRequested bool hcsContainer hcsshim.Container } func (ctr *container) newProcess(friendlyName string) *process { return &process{ processCommon: processCommon{ containerID: ctr.containerID, friendlyName: friendlyName, client: ctr.client, }, } } // start starts a created container. // Caller needs to lock container ID before calling this method. func (ctr *container) start(attachStdio StdioCallback) error { var err error isServicing := false for _, option := range ctr.options { if s, ok := option.(*ServicingOption); ok && s.IsServicing { isServicing = true } } // Start the container. If this is a servicing container, this call will block // until the container is done with the servicing execution. logrus.Debugln("libcontainerd: starting container ", ctr.containerID) if err = ctr.hcsContainer.Start(); err != nil { logrus.Errorf("libcontainerd: failed to start container: %s", err) if err := ctr.terminate(); err != nil { logrus.Errorf("libcontainerd: failed to cleanup after a failed Start. %s", err) } else { logrus.Debugln("libcontainerd: cleaned up after failed Start by calling Terminate") } return err } // Note we always tell HCS to // create stdout as it's required regardless of '-i' or '-t' options, so that // docker can always grab the output through logs. We also tell HCS to always // create stdin, even if it's not used - it will be closed shortly. Stderr // is only created if it we're not -t. createProcessParms := &hcsshim.ProcessConfig{ EmulateConsole: ctr.ociSpec.Process.Terminal, WorkingDirectory: ctr.ociSpec.Process.Cwd, CreateStdInPipe: !isServicing, CreateStdOutPipe: !isServicing, CreateStdErrPipe: !ctr.ociSpec.Process.Terminal && !isServicing, } createProcessParms.ConsoleSize[0] = uint(ctr.ociSpec.Process.ConsoleSize.Height) createProcessParms.ConsoleSize[1] = uint(ctr.ociSpec.Process.ConsoleSize.Width) // Configure the environment for the process createProcessParms.Environment = setupEnvironmentVariables(ctr.ociSpec.Process.Env) createProcessParms.CommandLine = strings.Join(ctr.ociSpec.Process.Args, " ") createProcessParms.User = ctr.ociSpec.Process.User.Username // Start the command running in the container. newProcess, err := ctr.hcsContainer.CreateProcess(createProcessParms) if err != nil { logrus.Errorf("libcontainerd: CreateProcess() failed %s", err) if err := ctr.terminate(); err != nil { logrus.Errorf("libcontainerd: failed to cleanup after a failed CreateProcess. %s", err) } else { logrus.Debugln("libcontainerd: cleaned up after failed CreateProcess by calling Terminate") } return err } pid := newProcess.Pid() // Save the hcs Process and PID ctr.process.friendlyName = InitFriendlyName ctr.process.hcsProcess = newProcess // If this is a servicing container, wait on the process synchronously here and // if it succeeds, wait for it cleanly shutdown and merge into the parent container. if isServicing { exitCode := ctr.waitProcessExitCode(&ctr.process) if exitCode != 0 { if err := ctr.terminate(); err != nil { logrus.Warnf("libcontainerd: terminating servicing container %s failed: %s", ctr.containerID, err) } return fmt.Errorf("libcontainerd: servicing container %s returned non-zero exit code %d", ctr.containerID, exitCode) } return ctr.hcsContainer.WaitTimeout(time.Minute * 5) } var stdout, stderr io.ReadCloser var stdin io.WriteCloser stdin, stdout, stderr, err = newProcess.Stdio() if err != nil { logrus.Errorf("libcontainerd: failed to get stdio pipes: %s", err) if err := ctr.terminate(); err != nil { logrus.Errorf("libcontainerd: failed to cleanup after a failed Stdio. %s", err) } return err } iopipe := &IOPipe{Terminal: ctr.ociSpec.Process.Terminal} iopipe.Stdin = createStdInCloser(stdin, newProcess) // Convert io.ReadClosers to io.Readers if stdout != nil { iopipe.Stdout = ioutil.NopCloser(&autoClosingReader{ReadCloser: stdout}) } if stderr != nil { iopipe.Stderr = ioutil.NopCloser(&autoClosingReader{ReadCloser: stderr}) } // Save the PID logrus.Debugf("libcontainerd: process started - PID %d", pid) ctr.systemPid = uint32(pid) // Spin up a go routine waiting for exit to handle cleanup go ctr.waitExit(&ctr.process, true) ctr.client.appendContainer(ctr) if err := attachStdio(*iopipe); err != nil { // OK to return the error here, as waitExit will handle tear-down in HCS return err } // Tell the docker engine that the container has started. si := StateInfo{ CommonStateInfo: CommonStateInfo{ State: StateStart, Pid: ctr.systemPid, // Not sure this is needed? Double-check monitor.go in daemon BUGBUG @jhowardmsft }} logrus.Debugf("libcontainerd: start() completed OK, %+v", si) return ctr.client.backend.StateChanged(ctr.containerID, si) } // waitProcessExitCode will wait for the given process to exit and return its error code. func (ctr *container) waitProcessExitCode(process *process) int { // Block indefinitely for the process to exit. err := process.hcsProcess.Wait() if err != nil { if herr, ok := err.(*hcsshim.ProcessError); ok && herr.Err != syscall.ERROR_BROKEN_PIPE { logrus.Warnf("libcontainerd: Wait() failed (container may have been killed): %s", err) } // Fall through here, do not return. This ensures we attempt to continue the // shutdown in HCS and tell the docker engine that the process/container // has exited to avoid a container being dropped on the floor. } exitCode, err := process.hcsProcess.ExitCode() if err != nil { if herr, ok := err.(*hcsshim.ProcessError); ok && herr.Err != syscall.ERROR_BROKEN_PIPE { logrus.Warnf("libcontainerd: unable to get exit code from container %s", ctr.containerID) } // Since we got an error retrieving the exit code, make sure that the code we return // doesn't incorrectly indicate success. exitCode = -1 // Fall through here, do not return. This ensures we attempt to continue the // shutdown in HCS and tell the docker engine that the process/container // has exited to avoid a container being dropped on the floor. } return exitCode } // waitExit runs as a goroutine waiting for the process to exit. It's // equivalent to (in the linux containerd world) where events come in for // state change notifications from containerd. func (ctr *container) waitExit(process *process, isFirstProcessToStart bool) error { logrus.Debugln("libcontainerd: waitExit() on pid", process.systemPid) exitCode := ctr.waitProcessExitCode(process) // Lock the container while removing the process/container from the list ctr.client.lock(ctr.containerID) if !isFirstProcessToStart { ctr.cleanProcess(process.friendlyName) } else { ctr.client.deleteContainer(ctr.containerID) } // Unlock here so other threads are unblocked ctr.client.unlock(ctr.containerID) // Assume the container has exited si := StateInfo{ CommonStateInfo: CommonStateInfo{ State: StateExit, ExitCode: uint32(exitCode), Pid: process.systemPid, ProcessID: process.friendlyName, }, UpdatePending: false, } // But it could have been an exec'd process which exited if !isFirstProcessToStart { si.State = StateExitProcess } else { updatePending, err := ctr.hcsContainer.HasPendingUpdates() if err != nil { logrus.Warnf("libcontainerd: HasPendingUpdates() failed (container may have been killed): %s", err) } else { si.UpdatePending = updatePending } logrus.Debugf("libcontainerd: shutting down container %s", ctr.containerID) if err := ctr.shutdown(); err != nil { logrus.Debugf("libcontainerd: failed to shutdown container %s", ctr.containerID) } else { logrus.Debugf("libcontainerd: completed shutting down container %s", ctr.containerID) } if err := ctr.hcsContainer.Close(); err != nil { logrus.Error(err) } } if err := process.hcsProcess.Close(); err != nil { logrus.Errorf("libcontainerd: hcsProcess.Close(): %v", err) } // Call into the backend to notify it of the state change. logrus.Debugf("libcontainerd: waitExit() calling backend.StateChanged %+v", si) if err := ctr.client.backend.StateChanged(ctr.containerID, si); err != nil { logrus.Error(err) } logrus.Debugf("libcontainerd: waitExit() completed OK, %+v", si) return nil } // cleanProcess removes process from the map. // Caller needs to lock container ID before calling this method. func (ctr *container) cleanProcess(id string) { delete(ctr.processes, id) } // shutdown shuts down the container in HCS // Caller needs to lock container ID before calling this method. func (ctr *container) shutdown() error { const shutdownTimeout = time.Minute * 5 err := ctr.hcsContainer.Shutdown() if hcsshim.IsPending(err) { // Explicit timeout to avoid a (remote) possibility that shutdown hangs indefinitely. err = ctr.hcsContainer.WaitTimeout(shutdownTimeout) } else if hcsshim.IsAlreadyStopped(err) { err = nil } if err != nil { logrus.Debugf("libcontainerd: error shutting down container %s %v calling terminate", ctr.containerID, err) if err := ctr.terminate(); err != nil { return err } return err } return nil } // terminate terminates the container in HCS // Caller needs to lock container ID before calling this method. func (ctr *container) terminate() error { const terminateTimeout = time.Minute * 5 err := ctr.hcsContainer.Terminate() if hcsshim.IsPending(err) { err = ctr.hcsContainer.WaitTimeout(terminateTimeout) } else if hcsshim.IsAlreadyStopped(err) { err = nil } if err != nil { logrus.Debugf("libcontainerd: error terminating container %s %v", ctr.containerID, err) return err } return nil }