Add functions which are used in Podman, CRI-O and containerd

Convenience functions to check if CRIU is available and at least a
certain version are now used in containerd, CRI-O and Podman. This
change moves those functions to go-criu.

Signed-off-by: Adrian Reber <[email protected]>

test/main.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/checkpoint-restore/go-criu/v7"
 	"github.com/checkpoint-restore/go-criu/v7/rpc"
+	"github.com/checkpoint-restore/go-criu/v7/utils"
 	"google.golang.org/protobuf/proto"
 )
 
@@ -126,6 +127,14 @@ func featureCheck(c *criu.Criu) error {
 		)
 	}
 
+	if utils.MemTrack() != featuresToCompare.GetMemTrack() {
+		return fmt.Errorf(
+			"unexpected MemTrack FeatureCheck result %v:%v",
+			utils.MemTrack(),
+			featuresToCompare.GetMemTrack(),
+		)
+	}
+
 	return nil
 }
 
@@ -139,6 +148,14 @@ func main() {
 		os.Exit(1)
 	}
 	log.Println("CRIU version", version)
+	// Compare if version from convenience function matches
+	version2, err := utils.GetCriuVersion()
+	if err != nil {
+		log.Fatalln(err)
+	}
+	if version != version2 {
+		log.Fatalf("Detected versions do not match (%d != %d)", version, version2)
+	}
 	// Check if version at least 3.2
 	result, err := c.IsCriuAtLeast(30200)
 	if err != nil {
@@ -148,6 +165,10 @@ func main() {
 		log.Fatalln("CRIU version to old")
 	}
 
+	if err := utils.CheckForCriu(30200); err != nil {
+		log.Fatalln(err)
+	}
+
 	if err = featureCheck(c); err != nil {
 		log.Fatalln(err)
 	}

utils/criu.go

@@ -0,0 +1,8 @@
+package utils
+
+// MinCriuVersion for Podman at least CRIU 3.11 is required
+const MinCriuVersionPodman = 31100
+
+// PodCriuVersion is the version of CRIU needed for
+// checkpointing and restoring containers out of and into Pods.
+const PodCriuVersion = 31600

utils/criu_linux.go

@@ -0,0 +1,45 @@
+//go:build linux
+// +build linux
+
+package utils
+
+import (
+	"fmt"
+
+	"github.com/checkpoint-restore/go-criu/v7"
+	"github.com/checkpoint-restore/go-criu/v7/rpc"
+	"google.golang.org/protobuf/proto"
+)
+
+// CheckForCRIU checks if CRIU is available and if it is as least the
+// version as specified in the "version" parameter.
+func CheckForCriu(version int) error {
+	criuVersion, err := GetCriuVersion()
+	if err != nil {
+		return fmt.Errorf("failed to check for criu version: %w", err)
+	}
+
+	if criuVersion >= version {
+		return nil
+	}
+	return fmt.Errorf("checkpoint/restore requires at least CRIU %d, current version is %d", version, criuVersion)
+}
+
+// Convenience function to easily check if memory tracking is supported.
+func MemTrack() bool {
+	features, err := criu.MakeCriu().FeatureCheck(
+		&rpc.CriuFeatures{
+			MemTrack: proto.Bool(true),
+		},
+	)
+	if err != nil {
+		return false
+	}
+
+	return features.GetMemTrack()
+}
+
+func GetCriuVersion() (int, error) {
+	c := criu.MakeCriu()
+	return c.GetCriuVersion()
+}

utils/criu_unsupported.go

@@ -0,0 +1,18 @@
+//go:build !linux
+// +build !linux
+
+package utils
+
+import "fmt"
+
+func CheckForCriu(version int) error {
+	return fmt.Errorf("CRIU not supported on this platform")
+}
+
+func MemTrack() bool {
+	return false
+}
+
+func GetCriuVersion() (int, error) {
+	return 0, fmt.Errorf("CRIU not supported in this platform")
+}