service.go

// +build linux

/*
   Copyright The containerd Authors.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package runc

import (
	"context"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"sync"
	"syscall"
	"time"

	"github.com/containerd/cgroups"
	"github.com/containerd/console"
	eventstypes "github.com/containerd/containerd/api/events"
	"github.com/containerd/containerd/api/types/task"
	"github.com/containerd/containerd/errdefs"
	"github.com/containerd/containerd/events"
	"github.com/containerd/containerd/mount"
	"github.com/containerd/containerd/namespaces"
	"github.com/containerd/containerd/runtime"
	rproc "github.com/containerd/containerd/runtime/proc"
	"github.com/containerd/containerd/runtime/v1/linux/proc"
	"github.com/containerd/containerd/runtime/v2/runc/options"
	"github.com/containerd/containerd/runtime/v2/shim"
	taskAPI "github.com/containerd/containerd/runtime/v2/task"
	runcC "github.com/containerd/go-runc"
	"github.com/containerd/typeurl"
	ptypes "github.com/gogo/protobuf/types"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
	"golang.org/x/sys/unix"
)

var (
	empty   = &ptypes.Empty{}
	bufPool = sync.Pool{
		New: func() interface{} {
			buffer := make([]byte, 32<<10)
			return &buffer
		},
	}
)

var _ = (taskAPI.TaskService)(&service{})

// New returns a new shim service that can be used via GRPC
func New(ctx context.Context, id string, publisher events.Publisher) (shim.Shim, error) {
	ep, err := newOOMEpoller(publisher)
	if err != nil {
		return nil, err
	}
	go ep.run(ctx)
	s := &service{
		id:        id,
		context:   ctx,
		processes: make(map[string]rproc.Process),
		events:    make(chan interface{}, 128),
		ec:        shim.Default.Subscribe(),
		ep:        ep,
	}
	go s.processExits()
	runcC.Monitor = shim.Default
	if err := s.initPlatform(); err != nil {
		return nil, errors.Wrap(err, "failed to initialized platform behavior")
	}
	go s.forward(publisher)
	return s, nil
}

// service is the shim implementation of a remote shim over GRPC
type service struct {
	mu sync.Mutex

	context   context.Context
	task      rproc.Process
	processes map[string]rproc.Process
	events    chan interface{}
	platform  rproc.Platform
	ec        chan runcC.Exit
	ep        *epoller

	id     string
	bundle string
	cg     cgroups.Cgroup
}

func newCommand(ctx context.Context, containerdBinary, containerdAddress string) (*exec.Cmd, error) {
	ns, err := namespaces.NamespaceRequired(ctx)
	if err != nil {
		return nil, err
	}
	self, err := os.Executable()
	if err != nil {
		return nil, err
	}
	cwd, err := os.Getwd()
	if err != nil {
		return nil, err
	}
	args := []string{
		"-namespace", ns,
		"-address", containerdAddress,
		"-publish-binary", containerdBinary,
	}
	cmd := exec.Command(self, args...)
	cmd.Dir = cwd
	cmd.Env = append(os.Environ(), "GOMAXPROCS=2")
	cmd.SysProcAttr = &syscall.SysProcAttr{
		Setpgid: true,
	}
	return cmd, nil
}

func (s *service) StartShim(ctx context.Context, id, containerdBinary, containerdAddress string) (string, error) {
	cmd, err := newCommand(ctx, containerdBinary, containerdAddress)
	if err != nil {
		return "", err
	}
	address, err := shim.SocketAddress(ctx, id)
	if err != nil {
		return "", err
	}
	socket, err := shim.NewSocket(address)
	if err != nil {
		return "", err
	}
	defer socket.Close()
	f, err := socket.File()
	if err != nil {
		return "", err
	}
	defer f.Close()

	cmd.ExtraFiles = append(cmd.ExtraFiles, f)

	if err := cmd.Start(); err != nil {
		return "", err
	}
	defer func() {
		if err != nil {
			cmd.Process.Kill()
		}
	}()
	// make sure to wait after start
	go cmd.Wait()
	if err := shim.WritePidFile("shim.pid", cmd.Process.Pid); err != nil {
		return "", err
	}
	if err := shim.WriteAddress("address", address); err != nil {
		return "", err
	}
	if err := shim.SetScore(cmd.Process.Pid); err != nil {
		return "", errors.Wrap(err, "failed to set OOM Score on shim")
	}
	return address, nil
}

func (s *service) Cleanup(ctx context.Context) (*taskAPI.DeleteResponse, error) {
	path, err := os.Getwd()
	if err != nil {
		return nil, err
	}
	ns, err := namespaces.NamespaceRequired(ctx)
	if err != nil {
		return nil, err
	}
	runtime, err := s.readRuntime(path)
	if err != nil {
		return nil, err
	}
	r := proc.NewRunc(proc.RuncRoot, path, ns, runtime, "", false)
	if err := r.Delete(ctx, s.id, &runcC.DeleteOpts{
		Force: true,
	}); err != nil {
		logrus.WithError(err).Warn("failed to remove runc container")
	}
	if err := mount.UnmountAll(filepath.Join(path, "rootfs"), 0); err != nil {
		logrus.WithError(err).Warn("failed to cleanup rootfs mount")
	}
	return &taskAPI.DeleteResponse{
		ExitedAt:   time.Now(),
		ExitStatus: 128 + uint32(unix.SIGKILL),
	}, nil
}

func (s *service) readRuntime(path string) (string, error) {
	data, err := ioutil.ReadFile(filepath.Join(path, "runtime"))
	if err != nil {
		return "", err
	}
	return string(data), nil
}

func (s *service) writeRuntime(path, runtime string) error {
	return ioutil.WriteFile(filepath.Join(path, "runtime"), []byte(runtime), 0600)
}

// Create a new initial process and container with the underlying OCI runtime
func (s *service) Create(ctx context.Context, r *taskAPI.CreateTaskRequest) (_ *taskAPI.CreateTaskResponse, err error) {
	s.mu.Lock()
	defer s.mu.Unlock()

	ns, err := namespaces.NamespaceRequired(ctx)
	if err != nil {
		return nil, errors.Wrap(err, "create namespace")
	}

	var opts options.Options
	if r.Options != nil {
		v, err := typeurl.UnmarshalAny(r.Options)
		if err != nil {
			return nil, err
		}
		opts = *v.(*options.Options)
	}

	var mounts []proc.Mount
	for _, m := range r.Rootfs {
		mounts = append(mounts, proc.Mount{
			Type:    m.Type,
			Source:  m.Source,
			Target:  m.Target,
			Options: m.Options,
		})
	}
	config := &proc.CreateConfig{
		ID:               r.ID,
		Bundle:           r.Bundle,
		Runtime:          opts.BinaryName,
		Rootfs:           mounts,
		Terminal:         r.Terminal,
		Stdin:            r.Stdin,
		Stdout:           r.Stdout,
		Stderr:           r.Stderr,
		Checkpoint:       r.Checkpoint,
		ParentCheckpoint: r.ParentCheckpoint,
		Options:          r.Options,
	}
	if err := s.writeRuntime(r.Bundle, opts.BinaryName); err != nil {
		return nil, err
	}
	rootfs := filepath.Join(r.Bundle, "rootfs")
	defer func() {
		if err != nil {
			if err2 := mount.UnmountAll(rootfs, 0); err2 != nil {
				logrus.WithError(err2).Warn("failed to cleanup rootfs mount")
			}
		}
	}()
	for _, rm := range mounts {
		m := &mount.Mount{
			Type:    rm.Type,
			Source:  rm.Source,
			Options: rm.Options,
		}
		if err := m.Mount(rootfs); err != nil {
			return nil, errors.Wrapf(err, "failed to mount rootfs component %v", m)
		}
	}
	process, err := newInit(
		ctx,
		r.Bundle,
		filepath.Join(r.Bundle, "work"),
		ns,
		s.platform,
		config,
		&opts,
	)
	if err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	if err := process.Create(ctx, config); err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	// save the main task id and bundle to the shim for additional requests
	s.id = r.ID
	s.bundle = r.Bundle
	pid := process.Pid()
	if pid > 0 {
		cg, err := cgroups.Load(cgroups.V1, cgroups.PidPath(pid))
		if err != nil {
			logrus.WithError(err).Errorf("loading cgroup for %d", pid)
		}
		s.setCgroup(cg)
	}
	s.task = process
	return &taskAPI.CreateTaskResponse{
		Pid: uint32(pid),
	}, nil

}

// Start a process
func (s *service) Start(ctx context.Context, r *taskAPI.StartRequest) (*taskAPI.StartResponse, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, err := s.getProcess(r.ExecID)
	if err != nil {
		return nil, err
	}
	if err := p.Start(ctx); err != nil {
		return nil, err
	}
	if s.cg == nil && p.Pid() > 0 {
		cg, err := cgroups.Load(cgroups.V1, cgroups.PidPath(p.Pid()))
		if err != nil {
			logrus.WithError(err).Errorf("loading cgroup for %d", p.Pid())
		}
		s.setCgroup(cg)
	}
	return &taskAPI.StartResponse{
		Pid: uint32(p.Pid()),
	}, nil
}

// Delete the initial process and container
func (s *service) Delete(ctx context.Context, r *taskAPI.DeleteRequest) (*taskAPI.DeleteResponse, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, err := s.getProcess(r.ExecID)
	if err != nil {
		return nil, err
	}
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	if err := p.Delete(ctx); err != nil {
		return nil, err
	}
	isTask := r.ExecID == ""
	if !isTask {
		delete(s.processes, r.ExecID)
	}
	if isTask && s.platform != nil {
		s.platform.Close()
	}
	return &taskAPI.DeleteResponse{
		ExitStatus: uint32(p.ExitStatus()),
		ExitedAt:   p.ExitedAt(),
		Pid:        uint32(p.Pid()),
	}, nil
}

// Exec an additional process inside the container
func (s *service) Exec(ctx context.Context, r *taskAPI.ExecProcessRequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if p := s.processes[r.ExecID]; p != nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrAlreadyExists, "id %s", r.ExecID)
	}
	p := s.task
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	process, err := p.(*proc.Init).Exec(ctx, s.bundle, &proc.ExecConfig{
		ID:       r.ExecID,
		Terminal: r.Terminal,
		Stdin:    r.Stdin,
		Stdout:   r.Stdout,
		Stderr:   r.Stderr,
		Spec:     r.Spec,
	})
	if err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	s.processes[r.ExecID] = process
	return empty, nil
}

// ResizePty of a process
func (s *service) ResizePty(ctx context.Context, r *taskAPI.ResizePtyRequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, err := s.getProcess(r.ExecID)
	if err != nil {
		return nil, err
	}
	ws := console.WinSize{
		Width:  uint16(r.Width),
		Height: uint16(r.Height),
	}
	if err := p.Resize(ws); err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	return empty, nil
}

// State returns runtime state information for a process
func (s *service) State(ctx context.Context, r *taskAPI.StateRequest) (*taskAPI.StateResponse, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, err := s.getProcess(r.ExecID)
	if err != nil {
		return nil, err
	}
	st, err := p.Status(ctx)
	if err != nil {
		return nil, err
	}
	status := task.StatusUnknown
	switch st {
	case "created":
		status = task.StatusCreated
	case "running":
		status = task.StatusRunning
	case "stopped":
		status = task.StatusStopped
	case "paused":
		status = task.StatusPaused
	case "pausing":
		status = task.StatusPausing
	}
	sio := p.Stdio()
	return &taskAPI.StateResponse{
		ID:         p.ID(),
		Bundle:     s.bundle,
		Pid:        uint32(p.Pid()),
		Status:     status,
		Stdin:      sio.Stdin,
		Stdout:     sio.Stdout,
		Stderr:     sio.Stderr,
		Terminal:   sio.Terminal,
		ExitStatus: uint32(p.ExitStatus()),
		ExitedAt:   p.ExitedAt(),
	}, nil
}

// Pause the container
func (s *service) Pause(ctx context.Context, r *taskAPI.PauseRequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p := s.task
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	if err := p.(*proc.Init).Pause(ctx); err != nil {
		return nil, err
	}
	return empty, nil
}

// Resume the container
func (s *service) Resume(ctx context.Context, r *taskAPI.ResumeRequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p := s.task
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	if err := p.(*proc.Init).Resume(ctx); err != nil {
		return nil, err
	}
	return empty, nil
}

// Kill a process with the provided signal
func (s *service) Kill(ctx context.Context, r *taskAPI.KillRequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, err := s.getProcess(r.ExecID)
	if err != nil {
		return nil, err
	}
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	if err := p.Kill(ctx, r.Signal, r.All); err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	return empty, nil
}

// Pids returns all pids inside the container
func (s *service) Pids(ctx context.Context, r *taskAPI.PidsRequest) (*taskAPI.PidsResponse, error) {
	pids, err := s.getContainerPids(ctx, r.ID)
	if err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	var processes []*task.ProcessInfo
	for _, pid := range pids {
		pInfo := task.ProcessInfo{
			Pid: pid,
		}
		for _, p := range s.processes {
			if p.Pid() == int(pid) {
				d := &options.ProcessDetails{
					ExecID: p.ID(),
				}
				a, err := typeurl.MarshalAny(d)
				if err != nil {
					return nil, errors.Wrapf(err, "failed to marshal process %d info", pid)
				}
				pInfo.Info = a
				break
			}
		}
		processes = append(processes, &pInfo)
	}
	return &taskAPI.PidsResponse{
		Processes: processes,
	}, nil
}

// CloseIO of a process
func (s *service) CloseIO(ctx context.Context, r *taskAPI.CloseIORequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p, err := s.getProcess(r.ExecID)
	if err != nil {
		return nil, err
	}
	if stdin := p.Stdin(); stdin != nil {
		if err := stdin.Close(); err != nil {
			return nil, errors.Wrap(err, "close stdin")
		}
	}
	return empty, nil
}

// Checkpoint the container
func (s *service) Checkpoint(ctx context.Context, r *taskAPI.CheckpointTaskRequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p := s.task
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	var opts options.CheckpointOptions
	if r.Options != nil {
		v, err := typeurl.UnmarshalAny(r.Options)
		if err != nil {
			return nil, err
		}
		opts = *v.(*options.CheckpointOptions)
	}
	if err := p.(*proc.Init).Checkpoint(ctx, &proc.CheckpointConfig{
		Path:                     r.Path,
		Exit:                     opts.Exit,
		AllowOpenTCP:             opts.OpenTcp,
		AllowExternalUnixSockets: opts.ExternalUnixSockets,
		AllowTerminal:            opts.Terminal,
		FileLocks:                opts.FileLocks,
		EmptyNamespaces:          opts.EmptyNamespaces,
	}); err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	return empty, nil
}

// Connect returns shim information such as the shim's pid
func (s *service) Connect(ctx context.Context, r *taskAPI.ConnectRequest) (*taskAPI.ConnectResponse, error) {
	var pid int
	if s.task != nil {
		pid = s.task.Pid()
	}
	return &taskAPI.ConnectResponse{
		ShimPid: uint32(os.Getpid()),
		TaskPid: uint32(pid),
	}, nil
}

func (s *service) Shutdown(ctx context.Context, r *taskAPI.ShutdownRequest) (*ptypes.Empty, error) {
	os.Exit(0)
	return empty, nil
}

func (s *service) Stats(ctx context.Context, r *taskAPI.StatsRequest) (*taskAPI.StatsResponse, error) {
	s.mu.Lock()
	defer s.mu.Unlock()

	if s.cg == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrNotFound, "cgroup does not exist")
	}
	stats, err := s.cg.Stat(cgroups.IgnoreNotExist)
	if err != nil {
		return nil, err
	}
	data, err := typeurl.MarshalAny(stats)
	if err != nil {
		return nil, err
	}
	return &taskAPI.StatsResponse{
		Stats: data,
	}, nil
}

// Update a running container
func (s *service) Update(ctx context.Context, r *taskAPI.UpdateTaskRequest) (*ptypes.Empty, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p := s.task
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	if err := p.(*proc.Init).Update(ctx, r.Resources); err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	return empty, nil
}

// Wait for a process to exit
func (s *service) Wait(ctx context.Context, r *taskAPI.WaitRequest) (*taskAPI.WaitResponse, error) {
	s.mu.Lock()
	p, err := s.getProcess(r.ExecID)
	s.mu.Unlock()
	if err != nil {
		return nil, err
	}
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	p.Wait()

	return &taskAPI.WaitResponse{
		ExitStatus: uint32(p.ExitStatus()),
		ExitedAt:   p.ExitedAt(),
	}, nil
}

func (s *service) processExits() {
	for e := range s.ec {
		s.checkProcesses(e)
	}
}

func (s *service) checkProcesses(e runcC.Exit) {
	s.mu.Lock()
	defer s.mu.Unlock()

	for _, p := range s.allProcesses() {
		if p.Pid() == e.Pid {
			if ip, ok := p.(*proc.Init); ok {
				// Ensure all children are killed
				if err := ip.KillAll(s.context); err != nil {
					logrus.WithError(err).WithField("id", ip.ID()).
						Error("failed to kill init's children")
				}
			}
			p.SetExited(e.Status)
			s.events <- &eventstypes.TaskExit{
				ContainerID: s.id,
				ID:          p.ID(),
				Pid:         uint32(e.Pid),
				ExitStatus:  uint32(e.Status),
				ExitedAt:    p.ExitedAt(),
			}
			return
		}
	}
}

func (s *service) allProcesses() (o []rproc.Process) {
	for _, p := range s.processes {
		o = append(o, p)
	}
	if s.task != nil {
		o = append(o, s.task)
	}
	return o
}

func (s *service) getContainerPids(ctx context.Context, id string) ([]uint32, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	p := s.task
	if p == nil {
		return nil, errors.Wrapf(errdefs.ErrFailedPrecondition, "container must be created")
	}
	ps, err := p.(*proc.Init).Runtime().Ps(ctx, id)
	if err != nil {
		return nil, err
	}
	pids := make([]uint32, 0, len(ps))
	for _, pid := range ps {
		pids = append(pids, uint32(pid))
	}
	return pids, nil
}

func (s *service) forward(publisher events.Publisher) {
	for e := range s.events {
		if err := publisher.Publish(s.context, getTopic(s.context, e), e); err != nil {
			logrus.WithError(err).Error("post event")
		}
	}
}

func (s *service) getProcess(execID string) (rproc.Process, error) {
	if execID == "" {
		return s.task, nil
	}
	p := s.processes[execID]
	if p == nil {
		return nil, errdefs.ToGRPCf(errdefs.ErrNotFound, "process does not exist %s", execID)
	}
	return p, nil
}

func (s *service) setCgroup(cg cgroups.Cgroup) {
	s.cg = cg
	if err := s.ep.add(s.id, cg); err != nil {
		logrus.WithError(err).Error("add cg to OOM monitor")
	}
}

func getTopic(ctx context.Context, e interface{}) string {
	switch e.(type) {
	case *eventstypes.TaskCreate:
		return runtime.TaskCreateEventTopic
	case *eventstypes.TaskStart:
		return runtime.TaskStartEventTopic
	case *eventstypes.TaskOOM:
		return runtime.TaskOOMEventTopic
	case *eventstypes.TaskExit:
		return runtime.TaskExitEventTopic
	case *eventstypes.TaskDelete:
		return runtime.TaskDeleteEventTopic
	case *eventstypes.TaskExecAdded:
		return runtime.TaskExecAddedEventTopic
	case *eventstypes.TaskExecStarted:
		return runtime.TaskExecStartedEventTopic
	case *eventstypes.TaskPaused:
		return runtime.TaskPausedEventTopic
	case *eventstypes.TaskResumed:
		return runtime.TaskResumedEventTopic
	case *eventstypes.TaskCheckpointed:
		return runtime.TaskCheckpointedEventTopic
	default:
		logrus.Warnf("no topic for type %#v", e)
	}
	return runtime.TaskUnknownTopic
}

func newInit(ctx context.Context, path, workDir, namespace string, platform rproc.Platform, r *proc.CreateConfig, options *options.Options) (*proc.Init, error) {
	rootfs := filepath.Join(path, "rootfs")
	runtime := proc.NewRunc(options.Root, path, namespace, options.BinaryName, options.CriuPath, options.SystemdCgroup)
	p := proc.New(r.ID, runtime, rproc.Stdio{
		Stdin:    r.Stdin,
		Stdout:   r.Stdout,
		Stderr:   r.Stderr,
		Terminal: r.Terminal,
	})
	p.Bundle = r.Bundle
	p.Platform = platform
	p.Rootfs = rootfs
	p.WorkDir = workDir
	p.IoUID = int(options.IoUid)
	p.IoGID = int(options.IoGid)
	p.NoPivotRoot = options.NoPivotRoot
	p.NoNewKeyring = options.NoNewKeyring
	return p, nil
}