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

2 files changed, 53 insertions, 4 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
 }