1 files changed, 154 insertions, 0 deletions
diff --git a/pkg/shim/v1/proc/exec_state.go b/pkg/shim/v1/proc/exec_state.go
new file mode 100644
index 000000000..4dcda8b44
--- /dev/null
+++ b/pkg/shim/v1/proc/exec_state.go
@@ -0,0 +1,154 @@
+// Copyright 2018 The containerd Authors.
+// Copyright 2018 The gVisor 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
+//
+//     https://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 proc
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/containerd/console"
+)
+
+type execState interface {
+	Resize(console.WinSize) error
+	Start(context.Context) error
+	Delete(context.Context) error
+	Kill(context.Context, uint32, bool) error
+	SetExited(int)
+}
+
+type execCreatedState struct {
+	p *execProcess
+}
+
+func (s *execCreatedState) transition(name string) error {
+	switch name {
+	case "running":
+		s.p.execState = &execRunningState{p: s.p}
+	case "stopped":
+		s.p.execState = &execStoppedState{p: s.p}
+	case "deleted":
+		s.p.execState = &deletedState{}
+	default:
+		return fmt.Errorf("invalid state transition %q to %q", stateName(s), name)
+	}
+	return nil
+}
+
+func (s *execCreatedState) Resize(ws console.WinSize) error {
+	return s.p.resize(ws)
+}
+
+func (s *execCreatedState) Start(ctx context.Context) error {
+	if err := s.p.start(ctx); err != nil {
+		return err
+	}
+	return s.transition("running")
+}
+
+func (s *execCreatedState) Delete(ctx context.Context) error {
+	if err := s.p.delete(ctx); err != nil {
+		return err
+	}
+	return s.transition("deleted")
+}
+
+func (s *execCreatedState) Kill(ctx context.Context, sig uint32, all bool) error {
+	return s.p.kill(ctx, sig, all)
+}
+
+func (s *execCreatedState) SetExited(status int) {
+	s.p.setExited(status)
+
+	if err := s.transition("stopped"); err != nil {
+		panic(err)
+	}
+}
+
+type execRunningState struct {
+	p *execProcess
+}
+
+func (s *execRunningState) transition(name string) error {
+	switch name {
+	case "stopped":
+		s.p.execState = &execStoppedState{p: s.p}
+	default:
+		return fmt.Errorf("invalid state transition %q to %q", stateName(s), name)
+	}
+	return nil
+}
+
+func (s *execRunningState) Resize(ws console.WinSize) error {
+	return s.p.resize(ws)
+}
+
+func (s *execRunningState) Start(ctx context.Context) error {
+	return fmt.Errorf("cannot start a running process")
+}
+
+func (s *execRunningState) Delete(ctx context.Context) error {
+	return fmt.Errorf("cannot delete a running process")
+}
+
+func (s *execRunningState) Kill(ctx context.Context, sig uint32, all bool) error {
+	return s.p.kill(ctx, sig, all)
+}
+
+func (s *execRunningState) SetExited(status int) {
+	s.p.setExited(status)
+
+	if err := s.transition("stopped"); err != nil {
+		panic(err)
+	}
+}
+
+type execStoppedState struct {
+	p *execProcess
+}
+
+func (s *execStoppedState) transition(name string) error {
+	switch name {
+	case "deleted":
+		s.p.execState = &deletedState{}
+	default:
+		return fmt.Errorf("invalid state transition %q to %q", stateName(s), name)
+	}
+	return nil
+}
+
+func (s *execStoppedState) Resize(ws console.WinSize) error {
+	return fmt.Errorf("cannot resize a stopped container")
+}
+
+func (s *execStoppedState) Start(ctx context.Context) error {
+	return fmt.Errorf("cannot start a stopped process")
+}
+
+func (s *execStoppedState) Delete(ctx context.Context) error {
+	if err := s.p.delete(ctx); err != nil {
+		return err
+	}
+	return s.transition("deleted")
+}
+
+func (s *execStoppedState) Kill(ctx context.Context, sig uint32, all bool) error {
+	return s.p.kill(ctx, sig, all)
+}
+
+func (s *execStoppedState) SetExited(status int) {
+	// no op
+}