Add runsc checkpoint command.

Checkpoint command is plumbed through container and sandbox.
Restore has also been added but it is only a stub. None of this
works yet. More changes to come.

PiperOrigin-RevId: 199510105
Change-Id: Ibd08d57f4737847eb25ca20b114518e487320185

runsc/cmd/BUILD

@@ -6,6 +6,7 @@ go_library(
     name = "cmd",
     srcs = [
         "boot.go",
+        "checkpoint.go",
         "cmd.go",
         "create.go",
         "delete.go",
@@ -16,6 +17,7 @@ go_library(
         "list.go",
         "path.go",
         "ps.go",
+        "restore.go",
         "run.go",
         "start.go",
         "state.go",

runsc/cmd/checkpoint.go

@@ -0,0 +1,70 @@
+// Copyright 2018 Google Inc.
+//
+// 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
+//
+//     http://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 cmd
+
+import (
+	"context"
+	"flag"
+	"github.com/google/subcommands"
+	"gvisor.googlesource.com/gvisor/runsc/boot"
+	"gvisor.googlesource.com/gvisor/runsc/container"
+)
+
+// Checkpoint implements subcommands.Command for the "checkpoint" command.
+type Checkpoint struct {
+}
+
+// Name implements subcommands.Command.Name.
+func (*Checkpoint) Name() string {
+	return "checkpoint"
+}
+
+// Synopsis implements subcommands.Command.Synopsis.
+func (*Checkpoint) Synopsis() string {
+	return "checkpoint current state of container"
+}
+
+// Usage implements subcommands.Command.Usage.
+func (*Checkpoint) Usage() string {
+	return `checkpoint [flags] <container id> - save current state of container.
+`
+}
+
+// SetFlags implements subcommands.Command.SetFlags.
+func (c *Checkpoint) SetFlags(f *flag.FlagSet) {
+}
+
+// Execute implements subcommands.Command.Execute.
+func (c *Checkpoint) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+
+	if f.NArg() != 1 {
+		f.Usage()
+		return subcommands.ExitUsageError
+	}
+
+	id := f.Arg(0)
+	conf := args[0].(*boot.Config)
+
+	cont, err := container.Load(conf.RootDir, id)
+	if err != nil {
+		Fatalf("error loading container: %v", err)
+	}
+
+	if err := cont.Checkpoint(); err != nil {
+		Fatalf("checkpoint failed: %v", err)
+	}
+
+	return subcommands.ExitSuccess
+}

runsc/cmd/restore.go

@@ -0,0 +1,51 @@
+// Copyright 2018 Google Inc.
+//
+// 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
+//
+//     http://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 cmd
+
+import (
+	"context"
+	"flag"
+	"github.com/google/subcommands"
+)
+
+// Restore implements subcommands.Command for the "restore" command.
+type Restore struct {
+}
+
+// Name implements subcommands.Command.Name.
+func (*Restore) Name() string {
+	return "restore"
+}
+
+// Synopsis implements subcommands.Command.Synopsis.
+func (*Restore) Synopsis() string {
+	return "restore a saved state of container"
+}
+
+// Usage implements subcommands.Command.Usage.
+func (*Restore) Usage() string {
+	return `restore [flags] <container id> - restore last saved state of container.
+`
+}
+
+// SetFlags implements subcommands.Command.SetFlags.
+func (r *Restore) SetFlags(f *flag.FlagSet) {
+}
+
+// Execute implements subcommands.Command.Execute.
+func (r *Restore) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+	Fatalf("restore not implemented")
+	return subcommands.ExitFailure
+}

runsc/container/container.go

@@ -299,6 +299,16 @@ func (c *Container) Signal(sig syscall.Signal) error {
 	return c.Sandbox.Signal(c.ID, sig)
 }
 
+// Checkpoint sends the checkpoint call to the container.
+func (c *Container) Checkpoint() error {
+	log.Debugf("Checkpoint container %q", c.ID)
+	if c.Status == Stopped {
+		log.Warningf("container %q not running, not checkpointing", c.ID)
+		return nil
+	}
+	return c.Sandbox.Checkpoint(c.ID)
+}
+
 // State returns the metadata of the container.
 func (c *Container) State() specs.State {
 	return specs.State{

runsc/sandbox/sandbox.go

@@ -440,6 +440,21 @@ func (s *Sandbox) Signal(cid string, sig syscall.Signal) error {
 	return nil
 }
 
+// Checkpoint sends the checkpoint call for a container in the sandbox.
+func (s *Sandbox) Checkpoint(cid string) error {
+	log.Debugf("Checkpoint sandbox %q", s.ID)
+	conn, err := s.connect()
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	if err := conn.Call(boot.ContainerCheckpoint, nil, nil); err != nil {
+		return fmt.Errorf("err checkpointing container %q: %v", cid, err)
+	}
+	return nil
+}
+
 // IsRunning returns true if the sandbox or gofer process is running.
 func (s *Sandbox) IsRunning() bool {
 	if s.Pid != 0 {