Remove main package dependency on criurpc

Commit 7f64fb47 made the main package, and runc/libcontainer's CriuOpts
depend on criu/rpc. This is not good; among the other things, it makes
it complicated to make c/r optional.

Let's switch CriuOpts.ManageCgroupsMode to a string (yes, it's an APIt
breaking change) and move the cgroup mode string parsing to
libcontainer.

While at it, let's better document ManageCgroupsMode.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

checkpoint.go

@@ -8,7 +8,6 @@ import (
 	"path/filepath"
 	"strconv"
 
-	criu "github.com/checkpoint-restore/go-criu/v6/rpc"
 	"github.com/moby/sys/userns"
 	"github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/sirupsen/logrus"
@@ -132,6 +131,7 @@ func criuOptions(context *cli.Context) (*libcontainer.CriuOpts, error) {
 		StatusFd:                context.Int("status-fd"),
 		LsmProfile:              context.String("lsm-profile"),
 		LsmMountContext:         context.String("lsm-mount-context"),
+		ManageCgroupsMode:       context.String("manage-cgroups-mode"),
 	}
 
 	// CRIU options below may or may not be set.
@@ -152,21 +152,6 @@ func criuOptions(context *cli.Context) (*libcontainer.CriuOpts, error) {
 		}
 	}
 
-	switch context.String("manage-cgroups-mode") {
-	case "":
-		// do nothing
-	case "soft":
-		opts.ManageCgroupsMode = criu.CriuCgMode_SOFT
-	case "full":
-		opts.ManageCgroupsMode = criu.CriuCgMode_FULL
-	case "strict":
-		opts.ManageCgroupsMode = criu.CriuCgMode_STRICT
-	case "ignore":
-		opts.ManageCgroupsMode = criu.CriuCgMode_IGNORE
-	default:
-		return nil, errors.New("Invalid manage-cgroups-mode value")
-	}
-
 	// runc doesn't manage network devices and their configuration.
 	nsmask := unix.CLONE_NEWNET
 

libcontainer/criu_linux.go

@@ -295,6 +295,11 @@ func (c *Container) Checkpoint(criuOpts *CriuOpts) error {
 		return errors.New("invalid directory to save checkpoint")
 	}
 
+	cgMode, err := criuCgMode(criuOpts.ManageCgroupsMode)
+	if err != nil {
+		return err
+	}
+
 	// Since a container can be C/R'ed multiple times,
 	// the checkpoint directory may already exist.
 	if err := os.Mkdir(criuOpts.ImagesDirectory, 0o700); err != nil && !os.IsExist(err) {
@@ -313,7 +318,8 @@ func (c *Container) Checkpoint(criuOpts *CriuOpts) error {
 		LogLevel:          proto.Int32(4),
 		LogFile:           proto.String(logFile),
 		Root:              proto.String(c.config.Rootfs),
-		ManageCgroups:   proto.Bool(true),
+		ManageCgroups:     proto.Bool(true), // Obsoleted by ManageCgroupsMode.
+		ManageCgroupsMode: &cgMode,
 		NotifyScripts:     proto.Bool(true),
 		Pid:               proto.Int32(int32(c.initProcess.pid())),
 		ShellJob:          proto.Bool(criuOpts.ShellJob),
@@ -381,12 +387,6 @@ func (c *Container) Checkpoint(criuOpts *CriuOpts) error {
 		rpcOpts.TrackMem = proto.Bool(true)
 	}
 
-	// append optional manage cgroups mode
-	if criuOpts.ManageCgroupsMode != 0 {
-		mode := criuOpts.ManageCgroupsMode
-		rpcOpts.ManageCgroupsMode = &mode
-	}
-
 	var t criurpc.CriuReqType
 	if criuOpts.PreDump {
 		feat := criurpc.CriuFeatures{
@@ -634,6 +634,12 @@ func (c *Container) Restore(process *Process, criuOpts *CriuOpts) error {
 	if criuOpts.ImagesDirectory == "" {
 		return errors.New("invalid directory to restore checkpoint")
 	}
+
+	cgMode, err := criuCgMode(criuOpts.ManageCgroupsMode)
+	if err != nil {
+		return err
+	}
+
 	logDir := criuOpts.ImagesDirectory
 	imageDir, err := os.Open(criuOpts.ImagesDirectory)
 	if err != nil {
@@ -669,7 +675,8 @@ func (c *Container) Restore(process *Process, criuOpts *CriuOpts) error {
 			LogFile:           proto.String(logFile),
 			RstSibling:        proto.Bool(true),
 			Root:              proto.String(root),
-			ManageCgroups:   proto.Bool(true),
+			ManageCgroups:     proto.Bool(true), // Obsoleted by ManageCgroupsMode.
+			ManageCgroupsMode: &cgMode,
 			NotifyScripts:     proto.Bool(true),
 			ShellJob:          proto.Bool(criuOpts.ShellJob),
 			ExtUnixSk:         proto.Bool(criuOpts.ExternalUnixConnections),
@@ -757,12 +764,6 @@ func (c *Container) Restore(process *Process, criuOpts *CriuOpts) error {
 		c.restoreNetwork(req, criuOpts)
 	}
 
-	// append optional manage cgroups mode
-	if criuOpts.ManageCgroupsMode != 0 {
-		mode := criuOpts.ManageCgroupsMode
-		req.Opts.ManageCgroupsMode = &mode
-	}
-
 	var (
 		fds    []string
 		fdJSON []byte
@@ -1184,3 +1185,20 @@ func (c *Container) criuNotifications(resp *criurpc.CriuResp, process *Process,
 	}
 	return nil
 }
+
+func criuCgMode(mode string) (criurpc.CriuCgMode, error) {
+	switch mode {
+	case "":
+		return criurpc.CriuCgMode_DEFAULT, nil
+	case "soft":
+		return criurpc.CriuCgMode_SOFT, nil
+	case "full":
+		return criurpc.CriuCgMode_FULL, nil
+	case "strict":
+		return criurpc.CriuCgMode_STRICT, nil
+	case "ignore":
+		return criurpc.CriuCgMode_IGNORE, nil
+	default:
+		return 0, errors.New("invalid manage-cgroups-mode value")
+	}
+}

libcontainer/criu_opts_linux.go

@@ -1,7 +1,5 @@
 package libcontainer
 
-import criu "github.com/checkpoint-restore/go-criu/v6/rpc"
-
 type CriuPageServerInfo struct {
 	Address string // IP address of CRIU page server
 	Port    int32  // port number of CRIU page server
@@ -24,11 +22,16 @@ type CriuOpts struct {
 	PreDump                 bool               // call criu predump to perform iterative checkpoint
 	PageServer              CriuPageServerInfo // allow to dump to criu page server
 	VethPairs               []VethPairName     // pass the veth to criu when restore
-	ManageCgroupsMode       criu.CriuCgMode    // dump or restore cgroup mode
 	EmptyNs                 uint32             // don't c/r properties for namespace from this mask
 	AutoDedup               bool               // auto deduplication for incremental dumps
 	LazyPages               bool               // restore memory pages lazily using userfaultfd
 	StatusFd                int                // fd for feedback when lazy server is ready
 	LsmProfile              string             // LSM profile used to restore the container
 	LsmMountContext         string             // LSM mount context value to use during restore
+
+	// ManageCgroupsMode tells how criu should manage cgroups during
+	// checkpoint or restore. Possible values are: "soft", "full",
+	// "strict", "ignore", or "" (empty string) for criu default.
+	// See https://criu.org/CGroups for more details.
+	ManageCgroupsMode string
 }