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|
package cgroups
import (
"io/ioutil"
"path/filepath"
"strings"
"time"
)
func NewFreezer(root string) *freezerController {
return &freezerController{
root: filepath.Join(root, string(Freezer)),
}
}
type freezerController struct {
root string
}
func (f *freezerController) Name() Name {
return Freezer
}
func (f *freezerController) Path(path string) string {
return filepath.Join(f.root, path)
}
func (f *freezerController) Freeze(path string) error {
if err := f.changeState(path, Frozen); err != nil {
return err
}
return f.waitState(path, Frozen)
}
func (f *freezerController) Thaw(path string) error {
if err := f.changeState(path, Thawed); err != nil {
return err
}
return f.waitState(path, Thawed)
}
func (f *freezerController) changeState(path string, state State) error {
return ioutil.WriteFile(
filepath.Join(f.root, path, "freezer.state"),
[]byte(strings.ToUpper(string(state))),
defaultFilePerm,
)
}
func (f *freezerController) state(path string) (State, error) {
current, err := ioutil.ReadFile(filepath.Join(f.root, path, "freezer.state"))
if err != nil {
return "", err
}
return State(strings.ToLower(strings.TrimSpace(string(current)))), nil
}
func (f *freezerController) waitState(path string, state State) error {
for {
current, err := f.state(path)
if err != nil {
return err
}
if current == state {
return nil
}
time.Sleep(1 * time.Millisecond)
}
}
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