1 files changed, 389 insertions, 0 deletions
diff --git a/vendor/github.com/containerd/cgroups/cgroup.go b/vendor/github.com/containerd/cgroups/cgroup.go
new file mode 100644
index 000000000..74a324f9e
--- /dev/null
+++ b/vendor/github.com/containerd/cgroups/cgroup.go
@@ -0,0 +1,389 @@
+package cgroups
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+// New returns a new control via the cgroup cgroups interface
+func New(hierarchy Hierarchy, path Path, resources *specs.LinuxResources) (Cgroup, error) {
+	subsystems, err := hierarchy()
+	if err != nil {
+		return nil, err
+	}
+	for _, s := range subsystems {
+		if err := initializeSubsystem(s, path, resources); err != nil {
+			return nil, err
+		}
+	}
+	return &cgroup{
+		path:       path,
+		subsystems: subsystems,
+	}, nil
+}
+
+// Load will load an existing cgroup and allow it to be controlled
+func Load(hierarchy Hierarchy, path Path) (Cgroup, error) {
+	subsystems, err := hierarchy()
+	if err != nil {
+		return nil, err
+	}
+	// check the the subsystems still exist
+	for _, s := range pathers(subsystems) {
+		p, err := path(s.Name())
+		if err != nil {
+			return nil, err
+		}
+		if _, err := os.Lstat(s.Path(p)); err != nil {
+			if os.IsNotExist(err) {
+				return nil, ErrCgroupDeleted
+			}
+			return nil, err
+		}
+	}
+	return &cgroup{
+		path:       path,
+		subsystems: subsystems,
+	}, nil
+}
+
+type cgroup struct {
+	path Path
+
+	subsystems []Subsystem
+	mu         sync.Mutex
+	err        error
+}
+
+// New returns a new sub cgroup
+func (c *cgroup) New(name string, resources *specs.LinuxResources) (Cgroup, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return nil, c.err
+	}
+	path := subPath(c.path, name)
+	for _, s := range c.subsystems {
+		if err := initializeSubsystem(s, path, resources); err != nil {
+			return nil, err
+		}
+	}
+	return &cgroup{
+		path:       path,
+		subsystems: c.subsystems,
+	}, nil
+}
+
+// Subsystems returns all the subsystems that are currently being
+// consumed by the group
+func (c *cgroup) Subsystems() []Subsystem {
+	return c.subsystems
+}
+
+// Add moves the provided process into the new cgroup
+func (c *cgroup) Add(process Process) error {
+	if process.Pid <= 0 {
+		return ErrInvalidPid
+	}
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return c.err
+	}
+	return c.add(process)
+}
+
+func (c *cgroup) add(process Process) error {
+	for _, s := range pathers(c.subsystems) {
+		p, err := c.path(s.Name())
+		if err != nil {
+			return err
+		}
+		if err := ioutil.WriteFile(
+			filepath.Join(s.Path(p), cgroupProcs),
+			[]byte(strconv.Itoa(process.Pid)),
+			defaultFilePerm,
+		); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Delete will remove the control group from each of the subsystems registered
+func (c *cgroup) Delete() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return c.err
+	}
+	var errors []string
+	for _, s := range c.subsystems {
+		if d, ok := s.(deleter); ok {
+			sp, err := c.path(s.Name())
+			if err != nil {
+				return err
+			}
+			if err := d.Delete(sp); err != nil {
+				errors = append(errors, string(s.Name()))
+			}
+			continue
+		}
+		if p, ok := s.(pather); ok {
+			sp, err := c.path(s.Name())
+			if err != nil {
+				return err
+			}
+			path := p.Path(sp)
+			if err := remove(path); err != nil {
+				errors = append(errors, path)
+			}
+		}
+	}
+	if len(errors) > 0 {
+		return fmt.Errorf("cgroups: unable to remove paths %s", strings.Join(errors, ", "))
+	}
+	c.err = ErrCgroupDeleted
+	return nil
+}
+
+// Stat returns the current stats for the cgroup
+func (c *cgroup) Stat(handlers ...ErrorHandler) (*Stats, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return nil, c.err
+	}
+	if len(handlers) == 0 {
+		handlers = append(handlers, errPassthrough)
+	}
+	var (
+		stats = &Stats{}
+		wg    = &sync.WaitGroup{}
+		errs  = make(chan error, len(c.subsystems))
+	)
+	for _, s := range c.subsystems {
+		if ss, ok := s.(stater); ok {
+			sp, err := c.path(s.Name())
+			if err != nil {
+				return nil, err
+			}
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				if err := ss.Stat(sp, stats); err != nil {
+					for _, eh := range handlers {
+						if herr := eh(err); herr != nil {
+							errs <- herr
+						}
+					}
+				}
+			}()
+		}
+	}
+	wg.Wait()
+	close(errs)
+	for err := range errs {
+		return nil, err
+	}
+	return stats, nil
+}
+
+// Update updates the cgroup with the new resource values provided
+//
+// Be prepared to handle EBUSY when trying to update a cgroup with
+// live processes and other operations like Stats being performed at the
+// same time
+func (c *cgroup) Update(resources *specs.LinuxResources) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return c.err
+	}
+	for _, s := range c.subsystems {
+		if u, ok := s.(updater); ok {
+			sp, err := c.path(s.Name())
+			if err != nil {
+				return err
+			}
+			if err := u.Update(sp, resources); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+// Processes returns the processes running inside the cgroup along
+// with the subsystem used, pid, and path
+func (c *cgroup) Processes(subsystem Name, recursive bool) ([]Process, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return nil, c.err
+	}
+	return c.processes(subsystem, recursive)
+}
+
+func (c *cgroup) processes(subsystem Name, recursive bool) ([]Process, error) {
+	s := c.getSubsystem(subsystem)
+	sp, err := c.path(subsystem)
+	if err != nil {
+		return nil, err
+	}
+	path := s.(pather).Path(sp)
+	var processes []Process
+	err = filepath.Walk(path, func(p string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if !recursive && info.IsDir() {
+			if p == path {
+				return nil
+			}
+			return filepath.SkipDir
+		}
+		dir, name := filepath.Split(p)
+		if name != cgroupProcs {
+			return nil
+		}
+		procs, err := readPids(dir, subsystem)
+		if err != nil {
+			return err
+		}
+		processes = append(processes, procs...)
+		return nil
+	})
+	return processes, err
+}
+
+// Freeze freezes the entire cgroup and all the processes inside it
+func (c *cgroup) Freeze() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return c.err
+	}
+	s := c.getSubsystem(Freezer)
+	if s == nil {
+		return ErrFreezerNotSupported
+	}
+	sp, err := c.path(Freezer)
+	if err != nil {
+		return err
+	}
+	return s.(*freezerController).Freeze(sp)
+}
+
+// Thaw thaws out the cgroup and all the processes inside it
+func (c *cgroup) Thaw() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return c.err
+	}
+	s := c.getSubsystem(Freezer)
+	if s == nil {
+		return ErrFreezerNotSupported
+	}
+	sp, err := c.path(Freezer)
+	if err != nil {
+		return err
+	}
+	return s.(*freezerController).Thaw(sp)
+}
+
+// OOMEventFD returns the memory cgroup's out of memory event fd that triggers
+// when processes inside the cgroup receive an oom event
+func (c *cgroup) OOMEventFD() (uintptr, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return 0, c.err
+	}
+	s := c.getSubsystem(Memory)
+	if s == nil {
+		return 0, ErrMemoryNotSupported
+	}
+	sp, err := c.path(Memory)
+	if err != nil {
+		return 0, err
+	}
+	return s.(*memoryController).OOMEventFD(sp)
+}
+
+// State returns the state of the cgroup and its processes
+func (c *cgroup) State() State {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.checkExists()
+	if c.err != nil && c.err == ErrCgroupDeleted {
+		return Deleted
+	}
+	s := c.getSubsystem(Freezer)
+	if s == nil {
+		return Thawed
+	}
+	sp, err := c.path(Freezer)
+	if err != nil {
+		return Unknown
+	}
+	state, err := s.(*freezerController).state(sp)
+	if err != nil {
+		return Unknown
+	}
+	return state
+}
+
+// MoveTo does a recursive move subsystem by subsystem of all the processes
+// inside the group
+func (c *cgroup) MoveTo(destination Cgroup) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.err != nil {
+		return c.err
+	}
+	for _, s := range c.subsystems {
+		processes, err := c.processes(s.Name(), true)
+		if err != nil {
+			return err
+		}
+		for _, p := range processes {
+			if err := destination.Add(p); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (c *cgroup) getSubsystem(n Name) Subsystem {
+	for _, s := range c.subsystems {
+		if s.Name() == n {
+			return s
+		}
+	}
+	return nil
+}
+
+func (c *cgroup) checkExists() {
+	for _, s := range pathers(c.subsystems) {
+		p, err := c.path(s.Name())
+		if err != nil {
+			return
+		}
+		if _, err := os.Lstat(s.Path(p)); err != nil {
+			if os.IsNotExist(err) {
+				c.err = ErrCgroupDeleted
+				return
+			}
+		}
+	}
+}