140 lines
3.2 KiB
Go
140 lines
3.2 KiB
Go
package cgroups
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import (
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"bytes"
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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specs "github.com/opencontainers/runtime-spec/specs-go"
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)
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func NewCputset(root string) *cpusetController {
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return &cpusetController{
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root: filepath.Join(root, string(Cpuset)),
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}
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}
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type cpusetController struct {
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root string
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}
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func (c *cpusetController) Name() Name {
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return Cpuset
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}
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func (c *cpusetController) Path(path string) string {
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return filepath.Join(c.root, path)
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}
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func (c *cpusetController) Create(path string, resources *specs.LinuxResources) error {
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if err := c.ensureParent(c.Path(path), c.root); err != nil {
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return err
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}
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if err := os.MkdirAll(c.Path(path), defaultDirPerm); err != nil {
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return err
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}
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if err := c.copyIfNeeded(c.Path(path), filepath.Dir(c.Path(path))); err != nil {
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return err
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}
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if resources.CPU != nil {
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for _, t := range []struct {
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name string
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value *string
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}{
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{
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name: "cpus",
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value: &resources.CPU.Cpus,
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},
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{
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name: "mems",
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value: &resources.CPU.Mems,
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},
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} {
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if t.value != nil {
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if err := ioutil.WriteFile(
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filepath.Join(c.Path(path), fmt.Sprintf("cpuset.%s", t.name)),
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[]byte(*t.value),
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defaultFilePerm,
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); err != nil {
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return err
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}
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}
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}
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}
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return nil
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}
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func (c *cpusetController) getValues(path string) (cpus []byte, mems []byte, err error) {
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if cpus, err = ioutil.ReadFile(filepath.Join(path, "cpuset.cpus")); err != nil && !os.IsNotExist(err) {
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return
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}
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if mems, err = ioutil.ReadFile(filepath.Join(path, "cpuset.mems")); err != nil && !os.IsNotExist(err) {
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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 (c *cpusetController) ensureParent(current, root string) error {
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parent := filepath.Dir(current)
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if _, err := filepath.Rel(root, parent); err != nil {
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return nil
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}
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if cleanPath(parent) == root {
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return nil
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}
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// Avoid infinite recursion.
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if parent == current {
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return fmt.Errorf("cpuset: cgroup parent path outside cgroup root")
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}
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if err := c.ensureParent(parent, root); err != nil {
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return err
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}
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if err := os.MkdirAll(current, defaultDirPerm); err != nil {
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return err
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}
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return c.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 (c *cpusetController) 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 = c.getValues(current); err != nil {
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return err
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}
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if parentCpus, parentMems, err = c.getValues(parent); err != nil {
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return err
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}
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if isEmpty(currentCpus) {
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if err := ioutil.WriteFile(
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filepath.Join(current, "cpuset.cpus"),
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parentCpus,
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defaultFilePerm,
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); err != nil {
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return err
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}
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}
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if isEmpty(currentMems) {
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if err := ioutil.WriteFile(
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filepath.Join(current, "cpuset.mems"),
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parentMems,
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defaultFilePerm,
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); 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 isEmpty(b []byte) bool {
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return len(bytes.Trim(b, "\n")) == 0
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}
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