Function getAvailableControllers

pkg/cgroups/cgroups.go:130–181

getAvailableControllers get the available controllers

(exclude map[string]controllerHandler, cgroup2 bool)

// getAvailableControllers get the available controllers
func getAvailableControllers(exclude map[string]controllerHandler, cgroup2 bool) ([]controller, error) {
	if cgroup2 {
		controllers := []controller{}
		controllersFile := cgroupRoot + "/cgroup.controllers"
		// rootless cgroupv2: check available controllers for current user, systemd or servicescope will inherit
		if unshare.IsRootless() {
			userSlice, err := getCgroupPathForCurrentProcess()
			if err != nil {
				return controllers, err
			}
			// userSlice already contains '/' so not adding here
			basePath := cgroupRoot + userSlice
			controllersFile = fmt.Sprintf("%s/cgroup.controllers", basePath)
		}
		controllersFileBytes, err := ioutil.ReadFile(controllersFile)
		if err != nil {
			return nil, errors.Wrapf(err, "failed while reading controllers for cgroup v2 from %q", controllersFile)
		}
		for _, controllerName := range strings.Fields(string(controllersFileBytes)) {
			c := controller{
				name:    controllerName,
				symlink: false,
			}
			controllers = append(controllers, c)
		}
		return controllers, nil
	}

	subsystems, _ := cgroupV1GetAllSubsystems()
	controllers := []controller{}
	// cgroupv1 and rootless: No subsystem is available: delegation is unsafe.
	if unshare.IsRootless() {
		return controllers, nil
	}

	for _, name := range subsystems {
		if _, found := exclude[name]; found {
			continue
		}
		fileInfo, err := os.Stat(cgroupRoot + "/" + name)
		if err != nil {
			continue
		}
		c := controller{
			name:    name,
			symlink: !fileInfo.IsDir(),
		}
		controllers = append(controllers, c)
	}

	return controllers, nil
}

// GetAvailableControllers get string:bool map of all the available controllers
func GetAvailableControllers(exclude map[string]controllerHandler, cgroup2 bool) ([]string, error) {