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Fixes #113

Signed-off-by: Marcos Lilljedahl <marcosnils@gmail.com>

vendor/github.com/opencontainers/runc/libcontainer/cgroups/systemd/apply_nosystemd.go

@@ -0,0 +1,55 @@
+// +build !linux
+
+package systemd
+
+import (
+	"fmt"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/configs"
+)
+
+type Manager struct {
+	Cgroups *configs.Cgroup
+	Paths   map[string]string
+}
+
+func UseSystemd() bool {
+	return false
+}
+
+func (m *Manager) Apply(pid int) error {
+	return fmt.Errorf("Systemd not supported")
+}
+
+func (m *Manager) GetPids() ([]int, error) {
+	return nil, fmt.Errorf("Systemd not supported")
+}
+
+func (m *Manager) GetAllPids() ([]int, error) {
+	return nil, fmt.Errorf("Systemd not supported")
+}
+
+func (m *Manager) Destroy() error {
+	return fmt.Errorf("Systemd not supported")
+}
+
+func (m *Manager) GetPaths() map[string]string {
+	return nil
+}
+
+func (m *Manager) GetStats() (*cgroups.Stats, error) {
+	return nil, fmt.Errorf("Systemd not supported")
+}
+
+func (m *Manager) Set(container *configs.Config) error {
+	return nil, fmt.Errorf("Systemd not supported")
+}
+
+func (m *Manager) Freeze(state configs.FreezerState) error {
+	return fmt.Errorf("Systemd not supported")
+}
+
+func Freeze(c *configs.Cgroup, state configs.FreezerState) error {
+	return fmt.Errorf("Systemd not supported")
+}

vendor/github.com/opencontainers/runc/libcontainer/cgroups/systemd/apply_systemd.go

@@ -0,0 +1,487 @@
+// +build linux
+
+package systemd
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	systemdDbus "github.com/coreos/go-systemd/dbus"
+	systemdUtil "github.com/coreos/go-systemd/util"
+	"github.com/godbus/dbus"
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/cgroups/fs"
+	"github.com/opencontainers/runc/libcontainer/configs"
+)
+
+type Manager struct {
+	mu      sync.Mutex
+	Cgroups *configs.Cgroup
+	Paths   map[string]string
+}
+
+type subsystem interface {
+	// Name returns the name of the subsystem.
+	Name() string
+	// Returns the stats, as 'stats', corresponding to the cgroup under 'path'.
+	GetStats(path string, stats *cgroups.Stats) error
+	// Set the cgroup represented by cgroup.
+	Set(path string, cgroup *configs.Cgroup) error
+}
+
+var errSubsystemDoesNotExist = errors.New("cgroup: subsystem does not exist")
+
+type subsystemSet []subsystem
+
+func (s subsystemSet) Get(name string) (subsystem, error) {
+	for _, ss := range s {
+		if ss.Name() == name {
+			return ss, nil
+		}
+	}
+	return nil, errSubsystemDoesNotExist
+}
+
+var subsystems = subsystemSet{
+	&fs.CpusetGroup{},
+	&fs.DevicesGroup{},
+	&fs.MemoryGroup{},
+	&fs.CpuGroup{},
+	&fs.CpuacctGroup{},
+	&fs.PidsGroup{},
+	&fs.BlkioGroup{},
+	&fs.HugetlbGroup{},
+	&fs.PerfEventGroup{},
+	&fs.FreezerGroup{},
+	&fs.NetPrioGroup{},
+	&fs.NetClsGroup{},
+	&fs.NameGroup{GroupName: "name=systemd"},
+}
+
+const (
+	testScopeWait = 4
+)
+
+var (
+	connLock                        sync.Mutex
+	theConn                         *systemdDbus.Conn
+	hasStartTransientUnit           bool
+	hasTransientDefaultDependencies bool
+)
+
+func newProp(name string, units interface{}) systemdDbus.Property {
+	return systemdDbus.Property{
+		Name:  name,
+		Value: dbus.MakeVariant(units),
+	}
+}
+
+func UseSystemd() bool {
+	if !systemdUtil.IsRunningSystemd() {
+		return false
+	}
+
+	connLock.Lock()
+	defer connLock.Unlock()
+
+	if theConn == nil {
+		var err error
+		theConn, err = systemdDbus.New()
+		if err != nil {
+			return false
+		}
+
+		// Assume we have StartTransientUnit
+		hasStartTransientUnit = true
+
+		// But if we get UnknownMethod error we don't
+		if _, err := theConn.StartTransientUnit("test.scope", "invalid", nil, nil); err != nil {
+			if dbusError, ok := err.(dbus.Error); ok {
+				if dbusError.Name == "org.freedesktop.DBus.Error.UnknownMethod" {
+					hasStartTransientUnit = false
+					return hasStartTransientUnit
+				}
+			}
+		}
+
+		// Ensure the scope name we use doesn't exist. Use the Pid to
+		// avoid collisions between multiple libcontainer users on a
+		// single host.
+		scope := fmt.Sprintf("libcontainer-%d-systemd-test-default-dependencies.scope", os.Getpid())
+		testScopeExists := true
+		for i := 0; i <= testScopeWait; i++ {
+			if _, err := theConn.StopUnit(scope, "replace", nil); err != nil {
+				if dbusError, ok := err.(dbus.Error); ok {
+					if strings.Contains(dbusError.Name, "org.freedesktop.systemd1.NoSuchUnit") {
+						testScopeExists = false
+						break
+					}
+				}
+			}
+			time.Sleep(time.Millisecond)
+		}
+
+		// Bail out if we can't kill this scope without testing for DefaultDependencies
+		if testScopeExists {
+			return hasStartTransientUnit
+		}
+
+		// Assume StartTransientUnit on a scope allows DefaultDependencies
+		hasTransientDefaultDependencies = true
+		ddf := newProp("DefaultDependencies", false)
+		if _, err := theConn.StartTransientUnit(scope, "replace", []systemdDbus.Property{ddf}, nil); err != nil {
+			if dbusError, ok := err.(dbus.Error); ok {
+				if strings.Contains(dbusError.Name, "org.freedesktop.DBus.Error.PropertyReadOnly") {
+					hasTransientDefaultDependencies = false
+				}
+			}
+		}
+
+		// Not critical because of the stop unit logic above.
+		theConn.StopUnit(scope, "replace", nil)
+	}
+	return hasStartTransientUnit
+}
+
+func getIfaceForUnit(unitName string) string {
+	if strings.HasSuffix(unitName, ".scope") {
+		return "Scope"
+	}
+	if strings.HasSuffix(unitName, ".service") {
+		return "Service"
+	}
+	return "Unit"
+}
+
+func (m *Manager) Apply(pid int) error {
+	var (
+		c          = m.Cgroups
+		unitName   = getUnitName(c)
+		slice      = "system.slice"
+		properties []systemdDbus.Property
+	)
+
+	if c.Paths != nil {
+		paths := make(map[string]string)
+		for name, path := range c.Paths {
+			_, err := getSubsystemPath(m.Cgroups, name)
+			if err != nil {
+				// Don't fail if a cgroup hierarchy was not found, just skip this subsystem
+				if cgroups.IsNotFound(err) {
+					continue
+				}
+				return err
+			}
+			paths[name] = path
+		}
+		m.Paths = paths
+		return cgroups.EnterPid(m.Paths, pid)
+	}
+
+	if c.Parent != "" {
+		slice = c.Parent
+	}
+
+	properties = append(properties,
+		systemdDbus.PropSlice(slice),
+		systemdDbus.PropDescription("docker container "+c.Name),
+		newProp("PIDs", []uint32{uint32(pid)}),
+	)
+
+	// Always enable accounting, this gets us the same behaviour as the fs implementation,
+	// plus the kernel has some problems with joining the memory cgroup at a later time.
+	properties = append(properties,
+		newProp("MemoryAccounting", true),
+		newProp("CPUAccounting", true),
+		newProp("BlockIOAccounting", true))
+
+	if hasTransientDefaultDependencies {
+		properties = append(properties,
+			newProp("DefaultDependencies", false))
+	}
+
+	if c.Resources.Memory != 0 {
+		properties = append(properties,
+			newProp("MemoryLimit", uint64(c.Resources.Memory)))
+	}
+
+	if c.Resources.CpuShares != 0 {
+		properties = append(properties,
+			newProp("CPUShares", uint64(c.Resources.CpuShares)))
+	}
+
+	if c.Resources.BlkioWeight != 0 {
+		properties = append(properties,
+			newProp("BlockIOWeight", uint64(c.Resources.BlkioWeight)))
+	}
+
+	// We need to set kernel memory before processes join cgroup because
+	// kmem.limit_in_bytes can only be set when the cgroup is empty.
+	// And swap memory limit needs to be set after memory limit, only
+	// memory limit is handled by systemd, so it's kind of ugly here.
+	if c.Resources.KernelMemory > 0 {
+		if err := setKernelMemory(c); err != nil {
+			return err
+		}
+	}
+
+	if _, err := theConn.StartTransientUnit(unitName, "replace", properties, nil); err != nil {
+		return err
+	}
+
+	if err := joinCgroups(c, pid); err != nil {
+		return err
+	}
+
+	paths := make(map[string]string)
+	for _, s := range subsystems {
+		subsystemPath, err := getSubsystemPath(m.Cgroups, s.Name())
+		if err != nil {
+			// Don't fail if a cgroup hierarchy was not found, just skip this subsystem
+			if cgroups.IsNotFound(err) {
+				continue
+			}
+			return err
+		}
+		paths[s.Name()] = subsystemPath
+	}
+	m.Paths = paths
+	return nil
+}
+
+func (m *Manager) Destroy() error {
+	if m.Cgroups.Paths != nil {
+		return nil
+	}
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	theConn.StopUnit(getUnitName(m.Cgroups), "replace", nil)
+	if err := cgroups.RemovePaths(m.Paths); err != nil {
+		return err
+	}
+	m.Paths = make(map[string]string)
+	return nil
+}
+
+func (m *Manager) GetPaths() map[string]string {
+	m.mu.Lock()
+	paths := m.Paths
+	m.mu.Unlock()
+	return paths
+}
+
+func writeFile(dir, file, data string) error {
+	// Normally dir should not be empty, one case is that cgroup subsystem
+	// is not mounted, we will get empty dir, and we want it fail here.
+	if dir == "" {
+		return fmt.Errorf("no such directory for %s.", file)
+	}
+	return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
+}
+
+func join(c *configs.Cgroup, subsystem string, pid int) (string, error) {
+	path, err := getSubsystemPath(c, subsystem)
+	if err != nil {
+		return "", err
+	}
+	if err := os.MkdirAll(path, 0755); err != nil {
+		return "", err
+	}
+	if err := writeFile(path, "cgroup.procs", strconv.Itoa(pid)); err != nil {
+		return "", err
+	}
+
+	return path, nil
+}
+
+func joinCgroups(c *configs.Cgroup, pid int) error {
+	for _, sys := range subsystems {
+		name := sys.Name()
+		switch name {
+		case "name=systemd":
+			// let systemd handle this
+			break
+		case "cpuset":
+			path, err := getSubsystemPath(c, name)
+			if err != nil && !cgroups.IsNotFound(err) {
+				return err
+			}
+			s := &fs.CpusetGroup{}
+			if err := s.ApplyDir(path, c, pid); err != nil {
+				return err
+			}
+			break
+		default:
+			_, err := join(c, name, pid)
+			if err != nil {
+				// Even if it's `not found` error, we'll return err
+				// because devices cgroup is hard requirement for
+				// container security.
+				if name == "devices" {
+					return err
+				}
+				// For other subsystems, omit the `not found` error
+				// because they are optional.
+				if !cgroups.IsNotFound(err) {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}
+
+// systemd represents slice heirarchy using `-`, so we need to follow suit when
+// generating the path of slice. Essentially, test-a-b.slice becomes
+// test.slice/test-a.slice/test-a-b.slice.
+func expandSlice(slice string) (string, error) {
+	suffix := ".slice"
+	// Name has to end with ".slice", but can't be just ".slice".
+	if len(slice) < len(suffix) || !strings.HasSuffix(slice, suffix) {
+		return "", fmt.Errorf("invalid slice name: %s", slice)
+	}
+
+	// Path-separators are not allowed.
+	if strings.Contains(slice, "/") {
+		return "", fmt.Errorf("invalid slice name: %s", slice)
+	}
+
+	var path, prefix string
+	sliceName := strings.TrimSuffix(slice, suffix)
+	for _, component := range strings.Split(sliceName, "-") {
+		// test--a.slice isn't permitted, nor is -test.slice.
+		if component == "" {
+			return "", fmt.Errorf("invalid slice name: %s", slice)
+		}
+
+		// Append the component to the path and to the prefix.
+		path += prefix + component + suffix + "/"
+		prefix += component + "-"
+	}
+
+	return path, nil
+}
+
+func getSubsystemPath(c *configs.Cgroup, subsystem string) (string, error) {
+	mountpoint, err := cgroups.FindCgroupMountpoint(subsystem)
+	if err != nil {
+		return "", err
+	}
+
+	initPath, err := cgroups.GetInitCgroupDir(subsystem)
+	if err != nil {
+		return "", err
+	}
+
+	slice := "system.slice"
+	if c.Parent != "" {
+		slice = c.Parent
+	}
+
+	slice, err = expandSlice(slice)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(mountpoint, initPath, slice, getUnitName(c)), nil
+}
+
+func (m *Manager) Freeze(state configs.FreezerState) error {
+	path, err := getSubsystemPath(m.Cgroups, "freezer")
+	if err != nil {
+		return err
+	}
+	prevState := m.Cgroups.Resources.Freezer
+	m.Cgroups.Resources.Freezer = state
+	freezer, err := subsystems.Get("freezer")
+	if err != nil {
+		return err
+	}
+	err = freezer.Set(path, m.Cgroups)
+	if err != nil {
+		m.Cgroups.Resources.Freezer = prevState
+		return err
+	}
+	return nil
+}
+
+func (m *Manager) GetPids() ([]int, error) {
+	path, err := getSubsystemPath(m.Cgroups, "devices")
+	if err != nil {
+		return nil, err
+	}
+	return cgroups.GetPids(path)
+}
+
+func (m *Manager) GetAllPids() ([]int, error) {
+	path, err := getSubsystemPath(m.Cgroups, "devices")
+	if err != nil {
+		return nil, err
+	}
+	return cgroups.GetAllPids(path)
+}
+
+func (m *Manager) GetStats() (*cgroups.Stats, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	stats := cgroups.NewStats()
+	for name, path := range m.Paths {
+		sys, err := subsystems.Get(name)
+		if err == errSubsystemDoesNotExist || !cgroups.PathExists(path) {
+			continue
+		}
+		if err := sys.GetStats(path, stats); err != nil {
+			return nil, err
+		}
+	}
+
+	return stats, nil
+}
+
+func (m *Manager) Set(container *configs.Config) error {
+	for _, sys := range subsystems {
+		// Get the subsystem path, but don't error out for not found cgroups.
+		path, err := getSubsystemPath(container.Cgroups, sys.Name())
+		if err != nil && !cgroups.IsNotFound(err) {
+			return err
+		}
+
+		if err := sys.Set(path, container.Cgroups); err != nil {
+			return err
+		}
+	}
+
+	if m.Paths["cpu"] != "" {
+		if err := fs.CheckCpushares(m.Paths["cpu"], container.Cgroups.Resources.CpuShares); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func getUnitName(c *configs.Cgroup) string {
+	return fmt.Sprintf("%s-%s.scope", c.ScopePrefix, c.Name)
+}
+
+func setKernelMemory(c *configs.Cgroup) error {
+	path, err := getSubsystemPath(c, "memory")
+	if err != nil && !cgroups.IsNotFound(err) {
+		return err
+	}
+
+	if err := os.MkdirAll(path, 0755); err != nil {
+		return err
+	}
+
+	// This doesn't get called by manager.Set, so we need to do it here.
+	s := &fs.MemoryGroup{}
+	return s.SetKernelMemory(path, c)
+}