Restore implementation added to runsc.

Restore creates a new container and uses the given image-path to load a saved
image of a previous container. Restore command is plumbed through container
and sandbox. This command does not work yet - more to come.

PiperOrigin-RevId: 201541229
Change-Id: I864a14c799ce3717d99bcdaaebc764281863d06f

6 files changed, 90 insertions, 23 deletions

diff --git a/runsc/cmd/create.go b/runsc/cmd/create.go
index 94a889077..5a887c73c 100644
--- a/runsc/cmd/create.go
+++ b/runsc/cmd/create.go
@@ -87,7 +87,7 @@ func (c *Create) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}
 	// Create the container. A new sandbox will be created for the
 	// container unless the metadata specifies that it should be run in an
 	// existing container.
-	if _, err := container.Create(id, spec, conf, bundleDir, c.consoleSocket, c.pidFile); err != nil {
+	if _, err := container.Create(id, spec, conf, bundleDir, c.consoleSocket, c.pidFile, ""); err != nil {
 		Fatalf("error creating container: %v", err)
 	}
 	return subcommands.ExitSuccess
diff --git a/runsc/cmd/restore.go b/runsc/cmd/restore.go
index a535197a4..0589a36bf 100644
--- a/runsc/cmd/restore.go
+++ b/runsc/cmd/restore.go
@@ -15,13 +15,23 @@
 package cmd
 
 import (
+	"syscall"
+
 	"context"
 	"flag"
 	"github.com/google/subcommands"
+	"gvisor.googlesource.com/gvisor/runsc/boot"
+	"gvisor.googlesource.com/gvisor/runsc/container"
+	"gvisor.googlesource.com/gvisor/runsc/specutils"
 )
 
 // Restore implements subcommands.Command for the "restore" command.
 type Restore struct {
+	// Restore flags are a super-set of those for Create.
+	Create
+
+	// imagePath is the path to the saved container image
+	imagePath string
 }
 
 // Name implements subcommands.Command.Name.
@@ -36,16 +46,55 @@ func (*Restore) Synopsis() string {
 
 // Usage implements subcommands.Command.Usage.
 func (*Restore) Usage() string {
-	return `restore [flags] <container id> - restore last saved state of container.
+	return `restore [flags] <container id> - restore saved state of container.
 `
 }
 
 // SetFlags implements subcommands.Command.SetFlags.
 func (r *Restore) SetFlags(f *flag.FlagSet) {
+	r.Create.SetFlags(f)
+	f.StringVar(&r.imagePath, "image-path", "", "path to saved container image")
 }
 
 // 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
+	if f.NArg() != 1 {
+		f.Usage()
+		return subcommands.ExitUsageError
+	}
+
+	id := f.Arg(0)
+	conf := args[0].(*boot.Config)
+	waitStatus := args[1].(*syscall.WaitStatus)
+
+	bundleDir := r.bundleDir
+	if bundleDir == "" {
+		bundleDir = getwdOrDie()
+	}
+	spec, err := specutils.ReadSpec(bundleDir)
+	if err != nil {
+		Fatalf("error reading spec: %v", err)
+	}
+	specutils.LogSpec(spec)
+
+	if r.imagePath == "" {
+		Fatalf("image-path flag must be provided")
+	}
+
+	cont, err := container.Create(id, spec, conf, bundleDir, r.consoleSocket, r.pidFile, r.imagePath)
+	if err != nil {
+		Fatalf("error restoring container: %v", err)
+	}
+
+	if err := cont.Start(conf); err != nil {
+		Fatalf("error starting container: %v", err)
+	}
+
+	ws, err := cont.Wait()
+	if err != nil {
+		Fatalf("error running container: %v", err)
+	}
+	*waitStatus = ws
+
+	return subcommands.ExitSuccess
 }
diff --git a/runsc/container/container.go b/runsc/container/container.go
index 3b7f95af9..604708e2c 100644
--- a/runsc/container/container.go
+++ b/runsc/container/container.go
@@ -188,7 +188,7 @@ func List(rootDir string) ([]string, error) {
 
 // Create creates the container in a new Sandbox process, unless the metadata
 // indicates that an existing Sandbox should be used.
-func Create(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket, pidFile string) (*Container, error) {
+func Create(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket, pidFile string, restoreFile string) (*Container, error) {
 	log.Debugf("Create container %q in root dir: %s", id, conf.RootDir)
 	if err := validateID(id); err != nil {
 		return nil, err
@@ -222,7 +222,7 @@ func Create(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSo
 		log.Debugf("Creating new sandbox for container %q", id)
 		// Start a new sandbox for this container. Any errors after this point
 		// must destroy the container.
-		s, err := sandbox.Create(id, spec, conf, bundleDir, consoleSocket)
+		s, err := sandbox.Create(id, spec, conf, bundleDir, consoleSocket, restoreFile)
 		if err != nil {
 			c.Destroy()
 			return nil, err
@@ -313,7 +313,7 @@ func (c *Container) Start(conf *boot.Config) error {
 // Run is a helper that calls Create + Start + Wait.
 func Run(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket, pidFile string) (syscall.WaitStatus, error) {
 	log.Debugf("Run container %q in root dir: %s", id, conf.RootDir)
-	c, err := Create(id, spec, conf, bundleDir, consoleSocket, pidFile)
+	c, err := Create(id, spec, conf, bundleDir, consoleSocket, pidFile, "")
 	if err != nil {
 		return 0, fmt.Errorf("error creating container: %v", err)
 	}
diff --git a/runsc/container/container_test.go b/runsc/container/container_test.go
index 5128f5946..a8320f614 100644
--- a/runsc/container/container_test.go
+++ b/runsc/container/container_test.go
@@ -117,7 +117,7 @@ func run(spec *specs.Spec) error {
 	defer os.RemoveAll(bundleDir)
 
 	// Create, start and wait for the container.
-	s, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
+	s, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
 	if err != nil {
 		return fmt.Errorf("error creating container: %v", err)
 	}
@@ -162,7 +162,7 @@ func TestLifecycle(t *testing.T) {
 	}
 	// Create the container.
 	id := testutil.UniqueContainerID()
-	if _, err := container.Create(id, spec, conf, bundleDir, "", ""); err != nil {
+	if _, err := container.Create(id, spec, conf, bundleDir, "", "", ""); err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}
 
@@ -360,7 +360,7 @@ func TestExec(t *testing.T) {
 	defer os.RemoveAll(bundleDir)
 
 	// Create and start the container.
-	s, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
+	s, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
 	if err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}
@@ -445,7 +445,7 @@ func TestCheckpoint(t *testing.T) {
 	defer os.RemoveAll(bundleDir)
 
 	// Create and start the container.
-	cont, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
+	cont, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
 	if err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}
@@ -497,7 +497,7 @@ func TestPauseResume(t *testing.T) {
 	defer os.RemoveAll(bundleDir)
 
 	// Create and start the container.
-	cont, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
+	cont, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
 	if err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}
@@ -599,7 +599,7 @@ func TestPauseResumeStatus(t *testing.T) {
 	defer os.RemoveAll(bundleDir)
 
 	// Create and start the container.
-	cont, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
+	cont, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
 	if err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}
@@ -666,7 +666,7 @@ func TestCapabilities(t *testing.T) {
 	defer os.RemoveAll(bundleDir)
 
 	// Create and start the container.
-	s, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
+	s, err := container.Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "", "")
 	if err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}
@@ -765,7 +765,7 @@ func TestConsoleSocket(t *testing.T) {
 
 	// Create the container and pass the socket name.
 	id := testutil.UniqueContainerID()
-	s, err := container.Create(id, spec, conf, bundleDir, socketRelPath, "")
+	s, err := container.Create(id, spec, conf, bundleDir, socketRelPath, "", "")
 	if err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}
@@ -828,7 +828,7 @@ func TestSpecUnsupported(t *testing.T) {
 	defer os.RemoveAll(bundleDir)
 
 	id := testutil.UniqueContainerID()
-	_, err = container.Create(id, spec, conf, bundleDir, "", "")
+	_, err = container.Create(id, spec, conf, bundleDir, "", "", "")
 	if err == nil || !strings.Contains(err.Error(), "is not supported") {
 		t.Errorf("container.Create() wrong error, got: %v, want: *is not supported, spec.Process: %+v", err, spec.Process)
 	}
@@ -917,7 +917,7 @@ func TestAbbreviatedIDs(t *testing.T) {
 		defer os.RemoveAll(bundleDir)
 
 		// Create and start the container.
-		cont, err := container.Create(cid, spec, conf, bundleDir, "", "")
+		cont, err := container.Create(cid, spec, conf, bundleDir, "", "", "")
 		if err != nil {
 			t.Fatalf("error creating container: %v", err)
 		}
@@ -987,7 +987,7 @@ func TestMultiContainerSanity(t *testing.T) {
 			t.Fatalf("error setting up container: %v", err)
 		}
 		defer os.RemoveAll(bundleDir)
-		cont, err := container.Create(containerIDs[i], spec, conf, bundleDir, "", "")
+		cont, err := container.Create(containerIDs[i], spec, conf, bundleDir, "", "", "")
 		if err != nil {
 			t.Fatalf("error creating container: %v", err)
 		}
diff --git a/runsc/sandbox/sandbox.go b/runsc/sandbox/sandbox.go
index 652910efa..870a0ccd3 100644
--- a/runsc/sandbox/sandbox.go
+++ b/runsc/sandbox/sandbox.go
@@ -54,7 +54,9 @@ type Sandbox struct {
 }
 
 // Create creates the sandbox process.
-func Create(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket string) (*Sandbox, error) {
+//
+// If restoreFile is not empty, the sandbox will be restored from file.
+func Create(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket string, restoreFile string) (*Sandbox, error) {
 	s := &Sandbox{ID: id}
 
 	binPath, err := specutils.BinPath()
@@ -69,7 +71,7 @@ func Create(id string, spec *specs.Spec, conf *boot.Config, bundleDir, consoleSo
 	}
 
 	// Create the sandbox process.
-	if err := s.createSandboxProcess(spec, conf, bundleDir, consoleSocket, binPath, ioFiles); err != nil {
+	if err := s.createSandboxProcess(spec, conf, bundleDir, consoleSocket, binPath, ioFiles, restoreFile); err != nil {
 		return nil, err
 	}
 
@@ -251,7 +253,7 @@ func (s *Sandbox) createGoferProcess(spec *specs.Spec, conf *boot.Config, bundle
 
 // createSandboxProcess starts the sandbox as a subprocess by running the "boot"
 // command, passing in the bundle dir.
-func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket, binPath string, ioFiles []*os.File) error {
+func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bundleDir, consoleSocket, binPath string, ioFiles []*os.File, restoreFile string) error {
 	// nextFD is used to get unused FDs that we can pass to the sandbox.  It
 	// starts at 3 because 0, 1, and 2 are taken by stdin/out/err.
 	nextFD := 3
@@ -273,12 +275,27 @@ func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bund
 		"--bundle", bundleDir,
 		"--controller-fd="+strconv.Itoa(nextFD),
 		fmt.Sprintf("--console=%t", consoleEnabled))
-	nextFD++
 
 	controllerFile := os.NewFile(uintptr(fd), "control_server_socket")
 	defer controllerFile.Close()
 	cmd.ExtraFiles = append(cmd.ExtraFiles, controllerFile)
 
+	// If a restore filename was given, open the file and append its FD to Args
+	// and the file to ExtraFiles.
+	if restoreFile != "" {
+		// Create the image file and open for reading.
+		rF, err := os.Open(restoreFile)
+		if err != nil {
+			return fmt.Errorf("os.Open(%q) failed: %v", restoreFile, err)
+		}
+		defer rF.Close()
+
+		nextFD++
+		cmd.Args = append(cmd.Args, "--restore-fd="+strconv.Itoa(nextFD))
+		cmd.ExtraFiles = append(cmd.ExtraFiles, rF)
+	}
+	nextFD++
+
 	// If there is a gofer, sends all socket ends to the sandbox.
 	for _, f := range ioFiles {
 		defer f.Close()
@@ -379,6 +396,7 @@ func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bund
 	}
 	s.Pid = cmd.Process.Pid
 	log.Infof("Sandbox started, pid: %d", s.Pid)
+
 	return nil
 }
 
diff --git a/runsc/sandbox/sandbox_test.go b/runsc/sandbox/sandbox_test.go
index fee2de283..9db90ef07 100644
--- a/runsc/sandbox/sandbox_test.go
+++ b/runsc/sandbox/sandbox_test.go
@@ -39,7 +39,7 @@ func TestGoferExits(t *testing.T) {
 	defer os.RemoveAll(bundleDir)
 
 	// Create, start and wait for the container.
-	s, err := Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "")
+	s, err := Create(testutil.UniqueContainerID(), spec, conf, bundleDir, "", "")
 	if err != nil {
 		t.Fatalf("error creating container: %v", err)
 	}