83 lines
1.9 KiB
Go
83 lines
1.9 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cgroups
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import (
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"io/ioutil"
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"path/filepath"
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"strings"
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"time"
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)
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func NewFreezer(root string) *freezerController {
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return &freezerController{
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root: filepath.Join(root, string(Freezer)),
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}
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}
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type freezerController struct {
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root string
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}
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func (f *freezerController) Name() Name {
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return Freezer
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}
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func (f *freezerController) Path(path string) string {
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return filepath.Join(f.root, path)
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}
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func (f *freezerController) Freeze(path string) error {
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return f.waitState(path, Frozen)
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}
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func (f *freezerController) Thaw(path string) error {
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return f.waitState(path, Thawed)
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}
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func (f *freezerController) changeState(path string, state State) error {
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return retryingWriteFile(
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filepath.Join(f.root, path, "freezer.state"),
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[]byte(strings.ToUpper(string(state))),
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defaultFilePerm,
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)
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}
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func (f *freezerController) state(path string) (State, error) {
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current, err := ioutil.ReadFile(filepath.Join(f.root, path, "freezer.state"))
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if err != nil {
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return "", err
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}
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return State(strings.ToLower(strings.TrimSpace(string(current)))), nil
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}
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func (f *freezerController) waitState(path string, state State) error {
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for {
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if err := f.changeState(path, state); err != nil {
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return err
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}
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current, err := f.state(path)
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if err != nil {
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return err
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}
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if current == state {
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return nil
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}
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time.Sleep(1 * time.Millisecond)
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}
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}
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