update vendor to use containerd cgroups

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

@@ -0,0 +1,158 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package cgroups
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+	"sync"
+
+	systemdDbus "github.com/coreos/go-systemd/v22/dbus"
+	"github.com/godbus/dbus/v5"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+const (
+	SystemdDbus  Name = "systemd"
+	defaultSlice      = "system.slice"
+)
+
+var (
+	canDelegate bool
+	once        sync.Once
+)
+
+func Systemd() ([]Subsystem, error) {
+	root, err := v1MountPoint()
+	if err != nil {
+		return nil, err
+	}
+	defaultSubsystems, err := defaults(root)
+	if err != nil {
+		return nil, err
+	}
+	s, err := NewSystemd(root)
+	if err != nil {
+		return nil, err
+	}
+	// make sure the systemd controller is added first
+	return append([]Subsystem{s}, defaultSubsystems...), nil
+}
+
+func Slice(slice, name string) Path {
+	if slice == "" {
+		slice = defaultSlice
+	}
+	return func(subsystem Name) (string, error) {
+		return filepath.Join(slice, name), nil
+	}
+}
+
+func NewSystemd(root string) (*SystemdController, error) {
+	return &SystemdController{
+		root: root,
+	}, nil
+}
+
+type SystemdController struct {
+	mu   sync.Mutex
+	root string
+}
+
+func (s *SystemdController) Name() Name {
+	return SystemdDbus
+}
+
+func (s *SystemdController) Create(path string, _ *specs.LinuxResources) error {
+	ctx := context.TODO()
+	conn, err := systemdDbus.NewWithContext(ctx)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+	slice, name := splitName(path)
+	// We need to see if systemd can handle the delegate property
+	// Systemd will return an error if it cannot handle delegate regardless
+	// of its bool setting.
+	checkDelegate := func() {
+		canDelegate = true
+		dlSlice := newProperty("Delegate", true)
+		if _, err := conn.StartTransientUnitContext(ctx, slice, "testdelegate", []systemdDbus.Property{dlSlice}, nil); err != nil {
+			if dbusError, ok := err.(dbus.Error); ok {
+				// Starting with systemd v237, Delegate is not even a property of slices anymore,
+				// so the D-Bus call fails with "InvalidArgs" error.
+				if strings.Contains(dbusError.Name, "org.freedesktop.DBus.Error.PropertyReadOnly") || strings.Contains(dbusError.Name, "org.freedesktop.DBus.Error.InvalidArgs") {
+					canDelegate = false
+				}
+			}
+		}
+
+		_, _ = conn.StopUnitContext(ctx, slice, "testDelegate", nil)
+	}
+	once.Do(checkDelegate)
+	properties := []systemdDbus.Property{
+		systemdDbus.PropDescription("cgroup " + name),
+		systemdDbus.PropWants(slice),
+		newProperty("DefaultDependencies", false),
+		newProperty("MemoryAccounting", true),
+		newProperty("CPUAccounting", true),
+		newProperty("BlockIOAccounting", true),
+	}
+
+	// If we can delegate, we add the property back in
+	if canDelegate {
+		properties = append(properties, newProperty("Delegate", true))
+	}
+
+	ch := make(chan string)
+	_, err = conn.StartTransientUnitContext(ctx, name, "replace", properties, ch)
+	if err != nil {
+		return err
+	}
+	<-ch
+	return nil
+}
+
+func (s *SystemdController) Delete(path string) error {
+	ctx := context.TODO()
+	conn, err := systemdDbus.NewWithContext(ctx)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+	_, name := splitName(path)
+	ch := make(chan string)
+	_, err = conn.StopUnitContext(ctx, name, "replace", ch)
+	if err != nil {
+		return err
+	}
+	<-ch
+	return nil
+}
+
+func newProperty(name string, units interface{}) systemdDbus.Property {
+	return systemdDbus.Property{
+		Name:  name,
+		Value: dbus.MakeVariant(units),
+	}
+}
+
+func splitName(path string) (slice string, unit string) {
+	slice, unit = filepath.Split(path)
+	return strings.TrimSuffix(slice, "/"), unit
+}