Use cached state instead of runc state.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/process/exec_state.go

@@ -31,6 +31,7 @@ type execState interface {
 	Delete(context.Context) error
 	Kill(context.Context, uint32, bool) error
 	SetExited(int)
+	Status(context.Context) (string, error)
 }
 
 type execCreatedState struct {
@@ -82,6 +83,10 @@ func (s *execCreatedState) SetExited(status int) {
 	}
 }
 
+func (s *execCreatedState) Status(ctx context.Context) (string, error) {
+	return "created", nil
+}
+
 type execRunningState struct {
 	p *execProcess
 }
@@ -120,6 +125,10 @@ func (s *execRunningState) SetExited(status int) {
 	}
 }
 
+func (s *execRunningState) Status(ctx context.Context) (string, error) {
+	return "running", nil
+}
+
 type execStoppedState struct {
 	p *execProcess
 }
@@ -157,3 +166,7 @@ func (s *execStoppedState) Kill(ctx context.Context, sig uint32, all bool) error
 func (s *execStoppedState) SetExited(status int) {
 	// no op
 }
+
+func (s *execStoppedState) Status(ctx context.Context) (string, error) {
+	return "stopped", nil
+}