Add DeleteProcess API for removing execs

We need a separate API for handing the exit status and deletion of
Exec'd processes to make sure they are properly cleaned up within the
shim and daemon.

Fixes #973

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

linux/shim/client.go

@@ -59,6 +59,10 @@ func (c *client) Delete(ctx context.Context, in *shimapi.DeleteRequest, opts ...
 	return c.s.Delete(ctx, in)
 }
 
+func (c *client) DeleteProcess(ctx context.Context, in *shimapi.DeleteProcessRequest, opts ...grpc.CallOption) (*shimapi.DeleteResponse, error) {
+	return c.s.DeleteProcess(ctx, in)
+}
+
 func (c *client) Exec(ctx context.Context, in *shimapi.ExecRequest, opts ...grpc.CallOption) (*shimapi.ExecResponse, error) {
 	return c.s.Exec(ctx, in)
 }

linux/shim/init.go

@@ -191,9 +191,16 @@ func (p *initProcess) Exited(status int) {
 }
 
 func (p *initProcess) Delete(context context.Context) error {
+	status, err := p.ContainerStatus(context)
+	if err != nil {
+		return err
+	}
+	if status != "stopped" {
+		return fmt.Errorf("cannot delete a running container")
+	}
 	p.killAll(context)
 	p.Wait()
-	err := p.runc.Delete(context, p.id)
+	err = p.runc.Delete(context, p.id)
 	if p.io != nil {
 		for _, c := range p.closers {
 			c.Close()

linux/shim/service.go

@@ -89,13 +89,29 @@ func (s *Service) Start(ctx context.Context, r *shimapi.StartRequest) (*google_p
 }
 
 func (s *Service) Delete(ctx context.Context, r *shimapi.DeleteRequest) (*shimapi.DeleteResponse, error) {
+	p := s.initProcess
+	// TODO (@crosbymichael): how to handle errors here
+	p.Delete(ctx)
+	s.mu.Lock()
+	delete(s.processes, p.Pid())
+	s.mu.Unlock()
+	return &shimapi.DeleteResponse{
+		ExitStatus: uint32(p.Status()),
+		ExitedAt:   p.ExitedAt(),
+	}, nil
+}
+
+func (s *Service) DeleteProcess(ctx context.Context, r *shimapi.DeleteProcessRequest) (*shimapi.DeleteResponse, error) {
+	if int(r.Pid) == s.initProcess.pid {
+		return nil, fmt.Errorf("cannot delete init process with DeleteProcess")
+	}
 	s.mu.Lock()
 	p, ok := s.processes[int(r.Pid)]
 	s.mu.Unlock()
 	if !ok {
-		p = s.initProcess
+		return nil, fmt.Errorf("process %d not found", r.Pid)
 	}
-	// TODO: how to handle errors here
+	// TODO (@crosbymichael): how to handle errors here
 	p.Delete(ctx)
 	s.mu.Lock()
 	delete(s.processes, p.Pid())

linux/task.go

@@ -158,6 +158,19 @@ func (c *Task) Checkpoint(ctx context.Context, opts plugin.CheckpointOpts) error
 	return err
 }
 
+func (c *Task) DeleteProcess(ctx context.Context, pid uint32) (*plugin.Exit, error) {
+	r, err := c.shim.DeleteProcess(ctx, &shim.DeleteProcessRequest{
+		Pid: pid,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &plugin.Exit{
+		Status:    r.ExitStatus,
+		Timestamp: r.ExitedAt,
+	}, nil
+}
+
 type Process struct {
 	pid int
 	c   *Task