| /* |
| 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 ( |
| "bytes" |
| "fmt" |
| "io/ioutil" |
| "os" |
| "path/filepath" |
| |
| specs "github.com/opencontainers/runtime-spec/specs-go" |
| ) |
| |
| func NewCputset(root string) *cpusetController { |
| return &cpusetController{ |
| root: filepath.Join(root, string(Cpuset)), |
| } |
| } |
| |
| type cpusetController struct { |
| root string |
| } |
| |
| func (c *cpusetController) Name() Name { |
| return Cpuset |
| } |
| |
| func (c *cpusetController) Path(path string) string { |
| return filepath.Join(c.root, path) |
| } |
| |
| func (c *cpusetController) Create(path string, resources *specs.LinuxResources) error { |
| if err := c.ensureParent(c.Path(path), c.root); err != nil { |
| return err |
| } |
| if err := os.MkdirAll(c.Path(path), defaultDirPerm); err != nil { |
| return err |
| } |
| if err := c.copyIfNeeded(c.Path(path), filepath.Dir(c.Path(path))); err != nil { |
| return err |
| } |
| if resources.CPU != nil { |
| for _, t := range []struct { |
| name string |
| value string |
| }{ |
| { |
| name: "cpus", |
| value: resources.CPU.Cpus, |
| }, |
| { |
| name: "mems", |
| value: resources.CPU.Mems, |
| }, |
| } { |
| if t.value != "" { |
| if err := ioutil.WriteFile( |
| filepath.Join(c.Path(path), fmt.Sprintf("cpuset.%s", t.name)), |
| []byte(t.value), |
| defaultFilePerm, |
| ); err != nil { |
| return err |
| } |
| } |
| } |
| } |
| return nil |
| } |
| |
| func (c *cpusetController) Update(path string, resources *specs.LinuxResources) error { |
| return c.Create(path, resources) |
| } |
| |
| func (c *cpusetController) getValues(path string) (cpus []byte, mems []byte, err error) { |
| if cpus, err = ioutil.ReadFile(filepath.Join(path, "cpuset.cpus")); err != nil && !os.IsNotExist(err) { |
| return |
| } |
| if mems, err = ioutil.ReadFile(filepath.Join(path, "cpuset.mems")); err != nil && !os.IsNotExist(err) { |
| return |
| } |
| return cpus, mems, nil |
| } |
| |
| // ensureParent makes sure that the parent directory of current is created |
| // and populated with the proper cpus and mems files copied from |
| // it's parent. |
| func (c *cpusetController) ensureParent(current, root string) error { |
| parent := filepath.Dir(current) |
| if _, err := filepath.Rel(root, parent); err != nil { |
| return nil |
| } |
| // Avoid infinite recursion. |
| if parent == current { |
| return fmt.Errorf("cpuset: cgroup parent path outside cgroup root") |
| } |
| if cleanPath(parent) != root { |
| if err := c.ensureParent(parent, root); err != nil { |
| return err |
| } |
| } |
| if err := os.MkdirAll(current, defaultDirPerm); err != nil { |
| return err |
| } |
| return c.copyIfNeeded(current, parent) |
| } |
| |
| // copyIfNeeded copies the cpuset.cpus and cpuset.mems from the parent |
| // directory to the current directory if the file's contents are 0 |
| func (c *cpusetController) copyIfNeeded(current, parent string) error { |
| var ( |
| err error |
| currentCpus, currentMems []byte |
| parentCpus, parentMems []byte |
| ) |
| if currentCpus, currentMems, err = c.getValues(current); err != nil { |
| return err |
| } |
| if parentCpus, parentMems, err = c.getValues(parent); err != nil { |
| return err |
| } |
| if isEmpty(currentCpus) { |
| if err := ioutil.WriteFile( |
| filepath.Join(current, "cpuset.cpus"), |
| parentCpus, |
| defaultFilePerm, |
| ); err != nil { |
| return err |
| } |
| } |
| if isEmpty(currentMems) { |
| if err := ioutil.WriteFile( |
| filepath.Join(current, "cpuset.mems"), |
| parentMems, |
| defaultFilePerm, |
| ); err != nil { |
| return err |
| } |
| } |
| return nil |
| } |
| |
| func isEmpty(b []byte) bool { |
| return len(bytes.Trim(b, "\n")) == 0 |
| } |