Fix error on doulbe Kill calls

This returns a typed error for calls to Kill when the process has
already finished.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

cmd/ctr/list.go

@@ -6,7 +6,7 @@ import (
 	"text/tabwriter"
 
 	"github.com/containerd/containerd"
-	"github.com/containerd/containerd/api/services/execution"
+	tasks "github.com/containerd/containerd/api/services/tasks/v1"
 	tasktypes "github.com/containerd/containerd/api/types/task"
 	"github.com/urfave/cli"
 )
@@ -67,9 +67,9 @@ func taskListFn(context *cli.Context) error {
 		return err
 	}
 
-	tasks := client.TaskService()
+	s := client.TaskService()
 
-	tasksResponse, err := tasks.List(ctx, &execution.ListRequest{})
+	tasksResponse, err := s.List(ctx, &tasks.ListTasksRequest{})
 	if err != nil {
 		return err
 	}

container.go

@@ -20,6 +20,7 @@ var (
 	ErrNoImage           = errors.New("container does not have an image")
 	ErrNoRunningTask     = errors.New("no running task")
 	ErrDeleteRunningTask = errors.New("cannot delete container with running task")
+	ErrProcessExited     = errors.New("process already exited")
 )
 
 type Container interface {

container_test.go

@@ -665,3 +665,72 @@ func TestDeleteRunningContainer(t *testing.T) {
 	}
 	<-statusC
 }
+
+func TestContainerKill(t *testing.T) {
+	if testing.Short() {
+		t.Skip()
+	}
+	client, err := New(address)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer client.Close()
+
+	var (
+		ctx, cancel = testContext()
+		id          = t.Name()
+	)
+	defer cancel()
+
+	image, err := client.GetImage(ctx, testImage)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	spec, err := GenerateSpec(WithImageConfig(ctx, image), WithProcessArgs("sh", "-c", "cat"))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	container, err := client.NewContainer(ctx, id, WithSpec(spec), WithImage(image), WithNewRootFS(id, image))
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer container.Delete(ctx)
+
+	task, err := container.NewTask(ctx, Stdio)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer task.Delete(ctx)
+
+	statusC := make(chan uint32, 1)
+	go func() {
+		status, err := task.Wait(ctx)
+		if err != nil {
+			t.Error(err)
+		}
+		statusC <- status
+	}()
+
+	if err := task.Start(ctx); err != nil {
+		t.Error(err)
+		return
+	}
+	if err := task.Kill(ctx, syscall.SIGKILL); err != nil {
+		t.Error(err)
+		return
+	}
+	<-statusC
+
+	err = task.Kill(ctx, syscall.SIGTERM)
+	if err == nil {
+		t.Error("second call to kill should return an error")
+		return
+	}
+	if err != ErrProcessExited {
+		t.Errorf("expected error %q but received %q", ErrProcessExited, err)
+	}
+}

linux/shim/exec.go

@@ -167,7 +167,10 @@ func (e *execProcess) Resize(ws console.WinSize) error {
 }
 
 func (e *execProcess) Signal(sig int) error {
-	return unix.Kill(e.pid, syscall.Signal(sig))
+	if err := unix.Kill(e.pid, syscall.Signal(sig)); err != nil {
+		return checkKillError(err)
+	}
+	return nil
 }
 
 func (e *execProcess) Stdin() io.Closer {

linux/shim/init.go

@@ -20,6 +20,7 @@ import (
 	shimapi "github.com/containerd/containerd/api/services/shim/v1"
 	"github.com/containerd/containerd/log"
 	"github.com/containerd/containerd/mount"
+	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/fifo"
 	runc "github.com/containerd/go-runc"
 	"github.com/pkg/errors"
@@ -234,7 +235,7 @@ func (p *initProcess) Kill(context context.Context, signal uint32, all bool) err
 	err := p.runc.Kill(context, p.id, int(signal), &runc.KillOpts{
 		All: all,
 	})
-	return p.runcError(err, "runc kill failed")
+	return checkKillError(err)
 }
 
 func (p *initProcess) killAll(context context.Context) error {
@@ -245,7 +246,7 @@ func (p *initProcess) killAll(context context.Context) error {
 }
 
 func (p *initProcess) Signal(sig int) error {
-	return unix.Kill(p.pid, syscall.Signal(sig))
+	return checkKillError(unix.Kill(p.pid, syscall.Signal(sig)))
 }
 
 func (p *initProcess) Stdin() io.Closer {
@@ -352,3 +353,13 @@ func copyFile(to, from string) error {
 	_, err = io.Copy(tt, ff)
 	return err
 }
+
+func checkKillError(err error) error {
+	if err == nil {
+		return nil
+	}
+	if strings.Contains(err.Error(), "os: process already finished") || err == unix.ESRCH {
+		return plugin.ErrProcessExited
+	}
+	return err
+}

linux/shim/service.go

@@ -274,12 +274,16 @@ func (s *Service) Kill(ctx context.Context, r *shimapi.KillRequest) (*google_pro
 		}
 		return empty, nil
 	}
-
+	if int(r.Pid) == s.initProcess.pid {
+		if err := s.initProcess.Kill(ctx, r.Signal, r.All); err != nil {
+			return nil, err
+		}
+		return empty, nil
+	}
 	pids, err := s.getContainerPids(ctx, s.initProcess.id)
 	if err != nil {
 		return nil, err
 	}
-
 	valid := false
 	for _, p := range pids {
 		if r.Pid == p {
@@ -287,15 +291,12 @@ func (s *Service) Kill(ctx context.Context, r *shimapi.KillRequest) (*google_pro
 			break
 		}
 	}
-
 	if !valid {
 		return nil, errors.Errorf("process %d does not exist in container", r.Pid)
 	}
-
 	if err := unix.Kill(int(r.Pid), syscall.Signal(r.Signal)); err != nil {
-		return nil, err
+		return nil, checkKillError(err)
 	}
-
 	return empty, nil
 }
 

plugin/errors.go

@@ -3,7 +3,8 @@ package plugin
 import "errors"
 
 var (
-	ErrContainerExists   = errors.New("container with id already exists")
-	ErrContainerNotExist = errors.New("container does not exist")
-	ErrRuntimeNotExist   = errors.New("runtime does not exist")
+	ErrContainerExists   = errors.New("runtime: container with id already exists")
+	ErrContainerNotExist = errors.New("runtime: container does not exist")
+	ErrRuntimeNotExist   = errors.New("runtime: runtime does not exist")
+	ErrProcessExited     = errors.New("runtime: process already exited")
 )

task.go

@@ -16,9 +16,11 @@ import (
 	tasktypes "github.com/containerd/containerd/api/types/task"
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/events"
+	"github.com/containerd/containerd/plugin"
 	"github.com/containerd/containerd/rootfs"
 	"github.com/opencontainers/image-spec/specs-go/v1"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
+	"google.golang.org/grpc"
 )
 
 const UnknownExitStatus = 255
@@ -108,11 +110,17 @@ func (t *task) Kill(ctx context.Context, s syscall.Signal) error {
 	_, err := t.client.TaskService().Kill(ctx, &tasks.KillRequest{
 		Signal:      uint32(s),
 		ContainerID: t.containerID,
-		PidOrAll: &tasks.KillRequest_All{
-			All: true,
+		PidOrAll: &tasks.KillRequest_Pid{
+			Pid: t.pid,
 		},
 	})
+	if err != nil {
+		if strings.Contains(grpc.ErrorDesc(err), plugin.ErrProcessExited.Error()) {
+			return ErrProcessExited
+		}
 		return err
+	}
+	return nil
 }
 
 func (t *task) Pause(ctx context.Context) error {