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

@@ -3,11 +3,13 @@ package main
 import (
  "fmt"
  "log"
+ "math"
  "os"
  "strconv"
 
  "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 +128,15 @@ func featureCheck(c *criu.Criu) error {
  )
  }
 
+ isMemTrack := utils.IsMemTrack()
+ if isMemTrack != featuresToCompare.GetMemTrack() {
+ return fmt.Errorf(
+ "unexpected MemTrack FeatureCheck result %v:%v",
+ isMemTrack,
+ featuresToCompare.GetMemTrack(),
+ )
+ }
+
  return nil
 }
 
@@ -139,6 +150,14 @@ 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 +167,14 @@ func main() {
  log.Fatalln("CRIU version to old")
  }
 
+ if err := utils.CheckForCriu(30200); err != nil {
+ log.Fatalln(err)
+ }
+
+ if err := utils.CheckForCriu(math.MaxInt); err == nil {
+ log.Fatalf("Checking for CRIU version %d should have failed.", math.MaxInt)
+ }
+
  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 +1,42 @@
+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 IsMemTrack() 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 IsMemTrack() bool {
+ return false
+}
+
+func GetCriuVersion() (int, error) {
+ return 0, fmt.Errorf("CRIU not supported in this platform")
+}