Method initProcessCgroupPath

libcontainer/process_linux.go:305–320

initProcessCgroupPath returns container init's cgroup path, as read from /proc/PID/cgroup. Only works for cgroup v2. Returns empty string if the path can not be obtained. This is used by runc exec in these cases: 1. On cgroup v2 + nesting + domain controllers, adding to initial cgroup may fail wit

()

//  2. A container init process with no cgroupns and /sys/fs/cgroup rw access
//     may move itself to any other cgroup, and the original cgroup will disappear.
func (p *setnsProcess) initProcessCgroupPath() string {
	if p.initProcessPid == 0 || !cgroups.IsCgroup2UnifiedMode() {
		return ""
	}

	cg, err := cgroups.ParseCgroupFile("/proc/" + strconv.Itoa(p.initProcessPid) + "/cgroup")
	if err != nil {
		return ""
	}
	cgroup, ok := cg[""]
	if !ok {
		return ""
	}

	return fs2.UnifiedMountpoint + cgroup
}

func (p *setnsProcess) addIntoCgroupV2() error {
	sub := p.process.SubCgroupPaths[""]