package fs
import (
"errors"
"os"
"path/filepath"
"strconv"
"strings"
"golang.org/x/sys/unix"
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
"github.com/opencontainers/runc/libcontainer/configs"
)
type CpusetGroup struct{}
func (s *CpusetGroup) Name() string {
return "cpuset"
}
func (s *CpusetGroup) Apply(path string, r *configs.Resources, pid int) error {
return s.ApplyDir(path, r, pid)
}
func (s *CpusetGroup) Set(path string, r *configs.Resources) error {
if r.CpusetCpus != "" {
if err := cgroups.WriteFile(path, "cpuset.cpus", r.CpusetCpus); err != nil {
return err
}
}
if r.CpusetMems != "" {
if err := cgroups.WriteFile(path, "cpuset.mems", r.CpusetMems); err != nil {
return err
}
}
return nil
}
func getCpusetStat(path string, file string) ([]uint16, error) {
var extracted []uint16
fileContent, err := fscommon.GetCgroupParamString(path, file)
if err != nil {
return extracted, err
}
if len(fileContent) == 0 {
return extracted, &parseError{Path: path, File: file, Err: errors.New("empty file")}
}
for _, s := range strings.Split(fileContent, ",") {
sp := strings.SplitN(s, "-", 3)
switch len(sp) {
case 3:
return extracted, &parseError{Path: path, File: file, Err: errors.New("extra dash")}
case 2:
min, err := strconv.ParseUint(sp[0], 10, 16)
if err != nil {
return extracted, &parseError{Path: path, File: file, Err: err}
}
max, err := strconv.ParseUint(sp[1], 10, 16)
if err != nil {
return extracted, &parseError{Path: path, File: file, Err: err}
}
if min > max {
return extracted, &parseError{Path: path, File: file, Err: errors.New("invalid values, min > max")}
}
for i := min; i <= max; i++ {
extracted = append(extracted, uint16(i))
}
case 1:
value, err := strconv.ParseUint(s, 10, 16)
if err != nil {
return extracted, &parseError{Path: path, File: file, Err: err}
}
extracted = append(extracted, uint16(value))
}
}
return extracted, nil
}
func (s *CpusetGroup) GetStats(path string, stats *cgroups.Stats) error {
var err error
stats.CPUSetStats.CPUs, err = getCpusetStat(path, "cpuset.cpus")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.CPUExclusive, err = fscommon.GetCgroupParamUint(path, "cpuset.cpu_exclusive")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.Mems, err = getCpusetStat(path, "cpuset.mems")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.MemHardwall, err = fscommon.GetCgroupParamUint(path, "cpuset.mem_hardwall")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.MemExclusive, err = fscommon.GetCgroupParamUint(path, "cpuset.mem_exclusive")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.MemoryMigrate, err = fscommon.GetCgroupParamUint(path, "cpuset.memory_migrate")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.MemorySpreadPage, err = fscommon.GetCgroupParamUint(path, "cpuset.memory_spread_page")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.MemorySpreadSlab, err = fscommon.GetCgroupParamUint(path, "cpuset.memory_spread_slab")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.MemoryPressure, err = fscommon.GetCgroupParamUint(path, "cpuset.memory_pressure")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.SchedLoadBalance, err = fscommon.GetCgroupParamUint(path, "cpuset.sched_load_balance")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
stats.CPUSetStats.SchedRelaxDomainLevel, err = fscommon.GetCgroupParamInt(path, "cpuset.sched_relax_domain_level")
if err != nil && !errors.Is(err, os.ErrNotExist) {
return err
}
return nil
}
func (s *CpusetGroup) ApplyDir(dir string, r *configs.Resources, pid int) error {
// This might happen if we have no cpuset cgroup mounted.
// Just do nothing and don't fail.
if dir == "" {
return nil
}
// 'ensureParent' start with parent because we don't want to
// explicitly inherit from parent, it could conflict with
// 'cpuset.cpu_exclusive'.
if err := cpusetEnsureParent(filepath.Dir(dir)); err != nil {
return err
}
if err := os.Mkdir(dir, 0o755); err != nil && !os.IsExist(err) {
return err
}
// We didn't inherit cpuset configs from parent, but we have
// to ensure cpuset configs are set before moving task into the
// cgroup.
// The logic is, if user specified cpuset configs, use these
// specified configs, otherwise, inherit from parent. This makes
// cpuset configs work correctly with 'cpuset.cpu_exclusive', and
// keep backward compatibility.
if err := s.ensureCpusAndMems(dir, r); err != nil {
return err
}
// Since we are not using apply(), we need to place the pid
// into the procs file.
return cgroups.WriteCgroupProc(dir, pid)
}
func getCpusetSubsystemSettings(parent string) (cpus, mems string, err error) {
if cpus, err = cgroups.ReadFile(parent, "cpuset.cpus"); err != nil {
return
}
if mems, err = cgroups.ReadFile(parent, "cpuset.mems"); err != nil {
return
}
return cpus, mems, nil
}
// cpusetEnsureParent makes sure that the parent directories of current
// are created and populated with the proper cpus and mems files copied
// from their respective parent. It does that recursively, starting from
// the top of the cpuset hierarchy (i.e. cpuset cgroup mount point).
func cpusetEnsureParent(current string) error {
var st unix.Statfs_t
parent := filepath.Dir(current)
err := unix.Statfs(parent, &st)
if err == nil && st.Type != unix.CGROUP_SUPER_MAGIC {
return nil
}
// Treat non-existing directory as cgroupfs as it will be created,
// and the root cpuset directory obviously exists.
if err != nil && err != unix.ENOENT { //nolint:errorlint // unix errors are bare
return &os.PathError{Op: "statfs", Path: parent, Err: err}
}
if err := cpusetEnsureParent(parent); err != nil {
return err
}
if err := os.Mkdir(current, 0o755); err != nil && !os.IsExist(err) {
return err
}
return cpusetCopyIfNeeded(current, parent)
}
// cpusetCopyIfNeeded copies the cpuset.cpus and cpuset.mems from the parent
// directory to the current directory if the file's contents are 0
func cpusetCopyIfNeeded(current, parent string) error {
currentCpus, currentMems, err := getCpusetSubsystemSettings(current)
if err != nil {
return err
}
parentCpus, parentMems, err := getCpusetSubsystemSettings(parent)
if err != nil {
return err
}
if isEmptyCpuset(currentCpus) {
if err := cgroups.WriteFile(current, "cpuset.cpus", parentCpus); err != nil {
return err
}
}
if isEmptyCpuset(currentMems) {
if err := cgroups.WriteFile(current, "cpuset.mems", parentMems); err != nil {
return err
}
}
return nil
}
func isEmptyCpuset(str string) bool {
return str == "" || str == "\n"
}
func (s *CpusetGroup) ensureCpusAndMems(path string, r *configs.Resources) error {
if err := s.Set(path, r); err != nil {
return err
}
return cpusetCopyIfNeeded(path, filepath.Dir(path))
}