139 lines
3.3 KiB
Go
139 lines
3.3 KiB
Go
// +build linux
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package fs
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import (
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"bytes"
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"io/ioutil"
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"os"
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"path/filepath"
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"strconv"
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"github.com/opencontainers/runc/libcontainer/cgroups"
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"github.com/opencontainers/runc/libcontainer/configs"
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)
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type CpusetGroup struct {
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}
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func (s *CpusetGroup) Name() string {
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return "cpuset"
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}
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func (s *CpusetGroup) Apply(d *cgroupData) error {
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dir, err := d.path("cpuset")
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if err != nil && !cgroups.IsNotFound(err) {
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return err
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}
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return s.ApplyDir(dir, d.config, d.pid)
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}
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func (s *CpusetGroup) Set(path string, cgroup *configs.Cgroup) error {
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if cgroup.CpusetCpus != "" {
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if err := writeFile(path, "cpuset.cpus", cgroup.CpusetCpus); err != nil {
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return err
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}
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}
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if cgroup.CpusetMems != "" {
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if err := writeFile(path, "cpuset.mems", cgroup.CpusetMems); err != nil {
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return err
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}
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}
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return nil
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}
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func (s *CpusetGroup) Remove(d *cgroupData) error {
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return removePath(d.path("cpuset"))
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}
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func (s *CpusetGroup) GetStats(path string, stats *cgroups.Stats) error {
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return nil
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}
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func (s *CpusetGroup) ApplyDir(dir string, cgroup *configs.Cgroup, pid int) error {
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// This might happen if we have no cpuset cgroup mounted.
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// Just do nothing and don't fail.
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if dir == "" {
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return nil
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}
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root, err := getCgroupRoot()
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if err != nil {
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return err
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}
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if err := s.ensureParent(dir, root); err != nil {
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return err
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}
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// the default values inherit from parent cgroup are already set in
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// s.ensureParent, cover these if we have our own
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if err := s.Set(dir, cgroup); err != nil {
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return err
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}
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// because we are not using d.join we need to place the pid into the procs file
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// unlike the other subsystems
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if err := writeFile(dir, "cgroup.procs", strconv.Itoa(pid)); err != nil {
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return err
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}
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return nil
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}
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func (s *CpusetGroup) getSubsystemSettings(parent string) (cpus []byte, mems []byte, err error) {
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if cpus, err = ioutil.ReadFile(filepath.Join(parent, "cpuset.cpus")); err != nil {
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return
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}
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if mems, err = ioutil.ReadFile(filepath.Join(parent, "cpuset.mems")); err != nil {
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return
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}
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return cpus, mems, nil
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}
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// ensureParent makes sure that the parent directory of current is created
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// and populated with the proper cpus and mems files copied from
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// it's parent.
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func (s *CpusetGroup) ensureParent(current, root string) error {
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parent := filepath.Dir(current)
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if filepath.Clean(parent) == root {
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return nil
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}
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if err := s.ensureParent(parent, root); err != nil {
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return err
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}
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if err := os.MkdirAll(current, 0755); err != nil {
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return err
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}
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return s.copyIfNeeded(current, parent)
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}
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// copyIfNeeded copies the cpuset.cpus and cpuset.mems from the parent
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// directory to the current directory if the file's contents are 0
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func (s *CpusetGroup) copyIfNeeded(current, parent string) error {
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var (
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err error
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currentCpus, currentMems []byte
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parentCpus, parentMems []byte
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)
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if currentCpus, currentMems, err = s.getSubsystemSettings(current); err != nil {
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return err
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}
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if parentCpus, parentMems, err = s.getSubsystemSettings(parent); err != nil {
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return err
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}
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if s.isEmpty(currentCpus) {
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if err := writeFile(current, "cpuset.cpus", string(parentCpus)); err != nil {
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return err
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}
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}
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if s.isEmpty(currentMems) {
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if err := writeFile(current, "cpuset.mems", string(parentMems)); err != nil {
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return err
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}
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}
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return nil
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}
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func (s *CpusetGroup) isEmpty(b []byte) bool {
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return len(bytes.Trim(b, "\n")) == 0
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}
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