oci: join crio-conmon for cgroupfs

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

vendor/github.com/containerd/cgroups/devices.go

@@ -0,0 +1,74 @@
+package cgroups
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+const (
+	allowDeviceFile = "devices.allow"
+	denyDeviceFile  = "devices.deny"
+	wildcard        = -1
+)
+
+func NewDevices(root string) *devicesController {
+	return &devicesController{
+		root: filepath.Join(root, string(Devices)),
+	}
+}
+
+type devicesController struct {
+	root string
+}
+
+func (d *devicesController) Name() Name {
+	return Devices
+}
+
+func (d *devicesController) Path(path string) string {
+	return filepath.Join(d.root, path)
+}
+
+func (d *devicesController) Create(path string, resources *specs.LinuxResources) error {
+	if err := os.MkdirAll(d.Path(path), defaultDirPerm); err != nil {
+		return err
+	}
+	for _, device := range resources.Devices {
+		file := denyDeviceFile
+		if device.Allow {
+			file = allowDeviceFile
+		}
+		if err := ioutil.WriteFile(
+			filepath.Join(d.Path(path), file),
+			[]byte(deviceString(device)),
+			defaultFilePerm,
+		); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (d *devicesController) Update(path string, resources *specs.LinuxResources) error {
+	return d.Create(path, resources)
+}
+
+func deviceString(device specs.LinuxDeviceCgroup) string {
+	return fmt.Sprintf("%c %s:%s %s",
+		&device.Type,
+		deviceNumber(device.Major),
+		deviceNumber(device.Minor),
+		&device.Access,
+	)
+}
+
+func deviceNumber(number *int64) string {
+	if number == nil || *number == wildcard {
+		return "*"
+	}
+	return fmt.Sprint(*number)
+}