| /* |
| Copyright The containerd Authors. |
| |
| Licensed under the Apache License, Version 2.0 (the "License"); |
| you may not use this file except in compliance with the License. |
| You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| */ |
| |
| 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 { |
| return f.waitState(path, Frozen) |
| } |
| |
| func (f *freezerController) Thaw(path string) error { |
| 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 { |
| if err := f.changeState(path, state); err != nil { |
| return err |
| } |
| current, err := f.state(path) |
| if err != nil { |
| return err |
| } |
| if current == state { |
| return nil |
| } |
| time.Sleep(1 * time.Millisecond) |
| } |
| } |