Merge pull request #339 from avagin/api-freezer

new-api: implement Pause() and Resume()

cgroups/fs/apply_raw.go

@@ -143,14 +143,16 @@ func (m *Manager) Freeze(state cgroups.FreezerState) error {
 		return err
 	}
 
+	prevState := m.Cgroups.Freezer
+	m.Cgroups.Freezer = state
+
 	freezer := subsystems["freezer"]
 	err = freezer.Set(d)
 	if err != nil {
+		m.Cgroups.Freezer = prevState
 		return err
 	}
 
-	m.Cgroups.Freezer = state
-
 	return nil
 }
 

integration/exec_test.go

@@ -204,6 +204,9 @@ func newTestRoot() (string, error) {
 }
 
 func TestEnter(t *testing.T) {
+	if testing.Short() {
+		return
+	}
 	root, err := newTestRoot()
 	if err != nil {
 		t.Fatal(err)
@@ -300,3 +303,77 @@ func TestEnter(t *testing.T) {
 		t.Fatal("The second process isn't in the required pid namespace", pidns, pidns2)
 	}
 }
+
+func TestFreeze(t *testing.T) {
+	if testing.Short() {
+		return
+	}
+	root, err := newTestRoot()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(root)
+
+	rootfs, err := newRootFs()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer remove(rootfs)
+
+	config := newTemplateConfig(rootfs)
+
+	factory, err := libcontainer.New(root, []string{os.Args[0], "init", "--"})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	container, err := factory.Create("test", config)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer container.Destroy()
+
+	stdinR, stdinW, err := os.Pipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	pconfig := libcontainer.ProcessConfig{
+		Args:  []string{"cat"},
+		Stdin: stdinR,
+	}
+	pid, err := container.StartProcess(&pconfig)
+	stdinR.Close()
+	defer stdinW.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	process, err := os.FindProcess(pid)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := container.Pause(); err != nil {
+		t.Fatal(err)
+	}
+	state, err := container.RunState()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if state != configs.Paused {
+		t.Fatal("Unexpected state: ", state)
+	}
+	if err := container.Resume(); err != nil {
+		t.Fatal(err)
+	}
+
+	stdinW.Close()
+	s, err := process.Wait()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !s.Success() {
+		t.Fatal(s.String())
+	}
+}

linux_container.go

@@ -48,6 +48,11 @@ func (c *linuxContainer) RunState() (configs.RunState, error) {
 		return 0, err
 	}
 
+	if c.config.Cgroups != nil &&
+		c.config.Cgroups.Freezer == cgroups.Frozen {
+		return configs.Paused, nil
+	}
+
 	//FIXME get a cgroup state to check other states
 
 	return configs.Running, nil
@@ -163,13 +168,11 @@ func (c *linuxContainer) Destroy() error {
 }
 
 func (c *linuxContainer) Pause() error {
-	glog.Info("pause container")
-	panic("not implemented")
+	return c.cgroupManager.Freeze(cgroups.Frozen)
 }
 
 func (c *linuxContainer) Resume() error {
-	glog.Info("resume container")
-	panic("not implemented")
+	return c.cgroupManager.Freeze(cgroups.Thawed)
 }
 
 func (c *linuxContainer) Signal(pid, signal int) error {

namespaces/exec.go

@@ -19,9 +19,7 @@ import (
 // Move this to libcontainer package.
 // Exec performs setup outside of a namespace so that a container can be
 // executed.  Exec is a high level function for working with container namespaces.
-func Exec(args []string, env []string, console string, command *exec.Cmd, container *configs.Config, cgroupManager cgroups.Manager, state *configs.State) error {
-	var err error
-
+func Exec(args []string, env []string, console string, command *exec.Cmd, container *configs.Config, cgroupManager cgroups.Manager, state *configs.State) (err error) {
 	// create a pipe so that we can syncronize with the namespaced process and
 	// pass the state and configuration to the child process
 	parent, child, err := newInitPipe()
@@ -73,7 +71,11 @@ func Exec(args []string, env []string, console string, command *exec.Cmd, contai
 	if err != nil {
 		return terminate(err)
 	}
-	defer cgroupManager.Destroy()
+	defer func() {
+		if err != nil {
+			cgroupManager.Destroy()
+		}
+	}()
 
 	var networkState network.NetworkState
 	if err := InitializeNetworking(container, command.Process.Pid, &networkState); err != nil {