Fixes a bug in runhcs shim Exec.Pid

When an exec occurs the pid was not properly updated on the in memory state
value causing many queries to see a 0.

Signed-off-by: Justin Terry (VM) <juterry@microsoft.com>

runtime/v2/runhcs/process.go

@@ -46,7 +46,6 @@ func newProcess(ctx context.Context, s *service, id string, pid uint32, pr *pipe
 	process := &process{
 		cid:       id,
 		id:        id,
-		pid:       pid,
 		bundle:    bundle,
 		stdin:     stdin,
 		stdout:    stdout,
@@ -55,6 +54,12 @@ func newProcess(ctx context.Context, s *service, id string, pid uint32, pr *pipe
 		relay:     pr,
 		waitBlock: make(chan struct{}),
 	}
+	go waitForProcess(ctx, process, p, s)
+	return process, nil
+}
+
+func waitForProcess(ctx context.Context, process *process, p *os.Process, s *service) {
+	pid := uint32(p.Pid)
 	// Store the default non-exited value for calls to stat
 	process.exit.Store(&processExit{
 		pid:        pid,
@@ -62,11 +67,7 @@ func newProcess(ctx context.Context, s *service, id string, pid uint32, pr *pipe
 		exitedAt:   time.Time{},
 		exitErr:    nil,
 	})
-	go waitForProcess(ctx, process, p, s)
-	return process, nil
-}
 
-func waitForProcess(ctx context.Context, process *process, p *os.Process, s *service) {
 	var status int
 	_, eerr := p.Wait()
 	if eerr != nil {
@@ -79,7 +80,7 @@ func waitForProcess(ctx context.Context, process *process, p *os.Process, s *ser
 	}
 	now := time.Now()
 	process.exit.Store(&processExit{
-		pid:        process.pid,
+		pid:        pid,
 		exitStatus: uint32(status),
 		exitedAt:   now,
 		exitErr:    eerr,
@@ -97,7 +98,7 @@ func waitForProcess(ctx context.Context, process *process, p *os.Process, s *ser
 		&eventstypes.TaskExit{
 			ContainerID: process.cid,
 			ID:          process.id,
-			Pid:         process.pid,
+			Pid:         pid,
 			ExitStatus:  uint32(status),
 			ExitedAt:    now,
 		})
@@ -117,6 +118,7 @@ func newExecProcess(ctx context.Context, s *service, cid, id string, pr *pipeRel
 	}
 	// Store the default non-exited value for calls to stat
 	process.exit.Store(&processExit{
+		pid:        0, // This is updated when the call to Start happens and the state is overwritten in waitForProcess.
 		exitStatus: 255,
 		exitedAt:   time.Time{},
 		exitErr:    nil,
@@ -129,7 +131,6 @@ type process struct {
 
 	cid string
 	id  string
-	pid uint32
 
 	bundle   string
 	stdin    string

runtime/v2/runhcs/service.go

@@ -325,7 +325,7 @@ func (s *service) State(ctx context.Context, r *taskAPI.StateRequest) (*taskAPI.
 	return &taskAPI.StateResponse{
 		ID:         p.id,
 		Bundle:     p.bundle,
-		Pid:        p.pid,
+		Pid:        pe.pid,
 		Status:     status,
 		Stdin:      p.stdin,
 		Stdout:     p.stdout,
@@ -667,7 +667,6 @@ func (s *service) Start(ctx context.Context, r *taskAPI.StartRequest) (*taskAPI.
 		if err != nil {
 			return nil, errors.Wrap(err, "failed to find exec process pid")
 		}
-		p.pid = uint32(pid)
 		go waitForProcess(ctx, p, proc, s)
 	} else {
 		if err := rhcs.Start(ctx, p.id); err != nil {
@@ -697,8 +696,9 @@ func (s *service) Start(ctx context.Context, r *taskAPI.StartRequest) (*taskAPI.
 			time.Sleep(1 * time.Second)
 		}
 	}
+	stat := p.stat()
 	return &taskAPI.StartResponse{
-		Pid: p.pid,
+		Pid: stat.pid,
 	}, nil
 }
 
@@ -738,7 +738,7 @@ func (s *service) Delete(ctx context.Context, r *taskAPI.DeleteRequest) (*taskAP
 	return &taskAPI.DeleteResponse{
 		ExitedAt:   exit.exitedAt,
 		ExitStatus: exit.exitStatus,
-		Pid:        p.pid,
+		Pid:        exit.pid,
 	}, nil
 }
 
@@ -908,7 +908,7 @@ func (s *service) ResizePty(ctx context.Context, r *taskAPI.ResizePtyRequest) (*
 		return nil, err
 	}
 
-	pid := int(p.pid)
+	pid := int(p.stat().pid)
 	opts := runhcs.ResizeTTYOpts{
 		Pid: &pid,
 	}
@@ -967,9 +967,15 @@ func (s *service) Stats(ctx context.Context, r *taskAPI.StatsRequest) (*taskAPI.
 func (s *service) Connect(ctx context.Context, r *taskAPI.ConnectRequest) (*taskAPI.ConnectResponse, error) {
 	log.G(ctx).Debugf("Connect: %s", r.ID)
 
+	var taskpid uint32
+	p, _ := s.getProcess(r.ID, "")
+	if p != nil {
+		taskpid = p.stat().pid
+	}
+
 	return &taskAPI.ConnectResponse{
 		ShimPid: uint32(os.Getpid()),
-		TaskPid: s.processes[s.id].pid,
+		TaskPid: taskpid,
 		Version: runhcsShimVersion,
 	}, nil
 }