libct/cgroups/utils: move cgroup v1 code to separate file
In most project, "utils" is a big mess, and this is not an exception. Try to clean it up a bit by moving cgroup v1 specific code to a separate source file. There are no code changes in this commit, just moving it from one file to another. Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This commit is contained in:
Kir Kolyshkin
parent
7db2d3e146
commit
0681d456fc
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@ -3,8 +3,6 @@
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package cgroups
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import (
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"fmt"
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"github.com/opencontainers/runc/libcontainer/configs"
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)
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@ -51,25 +49,3 @@ type Manager interface {
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// Whether the cgroup path exists or not
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Exists() bool
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}
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type NotFoundError struct {
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Subsystem string
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}
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func (e *NotFoundError) Error() string {
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return fmt.Sprintf("mountpoint for %s not found", e.Subsystem)
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}
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func NewNotFoundError(sub string) error {
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return &NotFoundError{
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Subsystem: sub,
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}
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}
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func IsNotFound(err error) bool {
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if err == nil {
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return false
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}
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_, ok := err.(*NotFoundError)
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return ok
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}
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@ -20,7 +20,6 @@ import (
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)
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const (
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CgroupNamePrefix = "name="
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CgroupProcesses = "cgroup.procs"
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unifiedMountpoint = "/sys/fs/cgroup"
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)
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@ -28,8 +27,6 @@ const (
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var (
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isUnifiedOnce sync.Once
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isUnified bool
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errUnified = errors.New("not implemented for cgroup v2 unified hierarchy")
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)
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// HugePageSizeUnitList is a list of the units used by the linux kernel when
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@ -51,126 +48,12 @@ func IsCgroup2UnifiedMode() bool {
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return isUnified
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}
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// https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt
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func FindCgroupMountpoint(cgroupPath, subsystem string) (string, error) {
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if IsCgroup2UnifiedMode() {
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return "", errUnified
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}
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mnt, _, err := FindCgroupMountpointAndRoot(cgroupPath, subsystem)
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return mnt, err
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}
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func FindCgroupMountpointAndRoot(cgroupPath, subsystem string) (string, string, error) {
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if IsCgroup2UnifiedMode() {
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return "", "", errUnified
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}
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// We are not using mount.GetMounts() because it's super-inefficient,
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// parsing it directly sped up x10 times because of not using Sscanf.
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// It was one of two major performance drawbacks in container start.
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if !isSubsystemAvailable(subsystem) {
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return "", "", NewNotFoundError(subsystem)
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}
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f, err := os.Open("/proc/self/mountinfo")
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if err != nil {
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return "", "", err
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}
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defer f.Close()
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return findCgroupMountpointAndRootFromReader(f, cgroupPath, subsystem)
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}
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func findCgroupMountpointAndRootFromReader(reader io.Reader, cgroupPath, subsystem string) (string, string, error) {
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scanner := bufio.NewScanner(reader)
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for scanner.Scan() {
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txt := scanner.Text()
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fields := strings.Fields(txt)
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if len(fields) < 9 {
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continue
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}
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if strings.HasPrefix(fields[4], cgroupPath) {
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for _, opt := range strings.Split(fields[len(fields)-1], ",") {
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if opt == subsystem {
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return fields[4], fields[3], nil
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}
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}
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}
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}
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if err := scanner.Err(); err != nil {
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return "", "", err
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}
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return "", "", NewNotFoundError(subsystem)
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}
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func isSubsystemAvailable(subsystem string) bool {
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if IsCgroup2UnifiedMode() {
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panic("don't call isSubsystemAvailable from cgroupv2 code")
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}
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cgroups, err := ParseCgroupFile("/proc/self/cgroup")
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if err != nil {
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return false
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}
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_, avail := cgroups[subsystem]
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return avail
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}
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type Mount struct {
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Mountpoint string
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Root string
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Subsystems []string
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}
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func (m Mount) GetOwnCgroup(cgroups map[string]string) (string, error) {
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if len(m.Subsystems) == 0 {
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return "", fmt.Errorf("no subsystem for mount")
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}
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return getControllerPath(m.Subsystems[0], cgroups)
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}
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func getCgroupMountsHelper(ss map[string]bool, mi io.Reader, all bool) ([]Mount, error) {
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res := make([]Mount, 0, len(ss))
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scanner := bufio.NewScanner(mi)
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numFound := 0
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for scanner.Scan() && numFound < len(ss) {
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txt := scanner.Text()
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sepIdx := strings.Index(txt, " - ")
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if sepIdx == -1 {
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return nil, fmt.Errorf("invalid mountinfo format")
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}
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if txt[sepIdx+3:sepIdx+10] == "cgroup2" || txt[sepIdx+3:sepIdx+9] != "cgroup" {
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continue
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}
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fields := strings.Split(txt, " ")
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m := Mount{
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Mountpoint: fields[4],
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Root: fields[3],
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}
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for _, opt := range strings.Split(fields[len(fields)-1], ",") {
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seen, known := ss[opt]
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if !known || (!all && seen) {
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continue
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}
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ss[opt] = true
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if strings.HasPrefix(opt, CgroupNamePrefix) {
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opt = opt[len(CgroupNamePrefix):]
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}
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m.Subsystems = append(m.Subsystems, opt)
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numFound++
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}
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if len(m.Subsystems) > 0 || all {
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res = append(res, m)
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}
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}
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if err := scanner.Err(); err != nil {
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return nil, err
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}
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return res, nil
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}
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// GetCgroupMounts returns the mounts for the cgroup subsystems.
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// all indicates whether to return just the first instance or all the mounts.
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// This function should not be used from cgroupv2 code, as in this case
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@ -193,25 +76,6 @@ func GetCgroupMounts(all bool) ([]Mount, error) {
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return getCgroupMountsV1(all)
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}
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func getCgroupMountsV1(all bool) ([]Mount, error) {
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f, err := os.Open("/proc/self/mountinfo")
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if err != nil {
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return nil, err
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}
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defer f.Close()
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allSubsystems, err := ParseCgroupFile("/proc/self/cgroup")
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if err != nil {
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return nil, err
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}
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allMap := make(map[string]bool)
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for s := range allSubsystems {
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allMap[s] = false
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}
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return getCgroupMountsHelper(allMap, f, all)
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}
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// GetAllSubsystems returns all the cgroup subsystems supported by the kernel
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func GetAllSubsystems() ([]string, error) {
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// /proc/cgroups is meaningless for v2
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@ -253,65 +117,6 @@ func GetAllSubsystems() ([]string, error) {
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return subsystems, nil
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}
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// GetOwnCgroup returns the relative path to the cgroup docker is running in.
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func GetOwnCgroup(subsystem string) (string, error) {
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if IsCgroup2UnifiedMode() {
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return "", errUnified
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}
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cgroups, err := ParseCgroupFile("/proc/self/cgroup")
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if err != nil {
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return "", err
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}
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return getControllerPath(subsystem, cgroups)
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}
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func GetOwnCgroupPath(subsystem string) (string, error) {
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cgroup, err := GetOwnCgroup(subsystem)
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if err != nil {
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return "", err
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}
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return getCgroupPathHelper(subsystem, cgroup)
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}
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func GetInitCgroup(subsystem string) (string, error) {
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if IsCgroup2UnifiedMode() {
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return "", errUnified
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}
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cgroups, err := ParseCgroupFile("/proc/1/cgroup")
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if err != nil {
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return "", err
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}
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return getControllerPath(subsystem, cgroups)
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}
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func GetInitCgroupPath(subsystem string) (string, error) {
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cgroup, err := GetInitCgroup(subsystem)
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if err != nil {
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return "", err
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}
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return getCgroupPathHelper(subsystem, cgroup)
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}
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func getCgroupPathHelper(subsystem, cgroup string) (string, error) {
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mnt, root, err := FindCgroupMountpointAndRoot("", subsystem)
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if err != nil {
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return "", err
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}
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// This is needed for nested containers, because in /proc/self/cgroup we
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// see paths from host, which don't exist in container.
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relCgroup, err := filepath.Rel(root, cgroup)
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if err != nil {
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return "", err
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}
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return filepath.Join(mnt, relCgroup), nil
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}
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func readProcsFile(file string) ([]int, error) {
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f, err := os.Open(file)
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if err != nil {
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@ -384,22 +189,6 @@ func parseCgroupFromReader(r io.Reader) (map[string]string, error) {
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return cgroups, nil
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}
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func getControllerPath(subsystem string, cgroups map[string]string) (string, error) {
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if IsCgroup2UnifiedMode() {
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return "", errUnified
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}
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if p, ok := cgroups[subsystem]; ok {
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return p, nil
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}
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if p, ok := cgroups[CgroupNamePrefix+subsystem]; ok {
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return p, nil
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}
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return "", NewNotFoundError(subsystem)
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}
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func PathExists(path string) bool {
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if _, err := os.Stat(path); err != nil {
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return false
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@ -0,0 +1,252 @@
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package cgroups
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import (
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"bufio"
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"errors"
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"fmt"
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"io"
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"os"
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"path/filepath"
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"strings"
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)
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// Code in this source file are specific to cgroup v1,
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// and must not be used from any cgroup v2 code.
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const (
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CgroupNamePrefix = "name="
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)
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var (
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errUnified = errors.New("not implemented for cgroup v2 unified hierarchy")
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)
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type NotFoundError struct {
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Subsystem string
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}
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func (e *NotFoundError) Error() string {
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return fmt.Sprintf("mountpoint for %s not found", e.Subsystem)
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}
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func NewNotFoundError(sub string) error {
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return &NotFoundError{
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Subsystem: sub,
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}
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}
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func IsNotFound(err error) bool {
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if err == nil {
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return false
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}
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_, ok := err.(*NotFoundError)
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return ok
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}
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// https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt
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func FindCgroupMountpoint(cgroupPath, subsystem string) (string, error) {
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if IsCgroup2UnifiedMode() {
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return "", errUnified
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}
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mnt, _, err := FindCgroupMountpointAndRoot(cgroupPath, subsystem)
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return mnt, err
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}
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func FindCgroupMountpointAndRoot(cgroupPath, subsystem string) (string, string, error) {
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if IsCgroup2UnifiedMode() {
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return "", "", errUnified
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}
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// We are not using mount.GetMounts() because it's super-inefficient,
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// parsing it directly sped up x10 times because of not using Sscanf.
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// It was one of two major performance drawbacks in container start.
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if !isSubsystemAvailable(subsystem) {
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return "", "", NewNotFoundError(subsystem)
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}
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f, err := os.Open("/proc/self/mountinfo")
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if err != nil {
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return "", "", err
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}
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defer f.Close()
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return findCgroupMountpointAndRootFromReader(f, cgroupPath, subsystem)
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}
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func findCgroupMountpointAndRootFromReader(reader io.Reader, cgroupPath, subsystem string) (string, string, error) {
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scanner := bufio.NewScanner(reader)
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for scanner.Scan() {
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txt := scanner.Text()
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fields := strings.Fields(txt)
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if len(fields) < 9 {
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continue
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}
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if strings.HasPrefix(fields[4], cgroupPath) {
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for _, opt := range strings.Split(fields[len(fields)-1], ",") {
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if opt == subsystem {
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return fields[4], fields[3], nil
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}
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}
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}
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}
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if err := scanner.Err(); err != nil {
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return "", "", err
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}
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return "", "", NewNotFoundError(subsystem)
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}
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func isSubsystemAvailable(subsystem string) bool {
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if IsCgroup2UnifiedMode() {
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panic("don't call isSubsystemAvailable from cgroupv2 code")
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}
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cgroups, err := ParseCgroupFile("/proc/self/cgroup")
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if err != nil {
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return false
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}
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_, avail := cgroups[subsystem]
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return avail
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}
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func (m Mount) GetOwnCgroup(cgroups map[string]string) (string, error) {
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if len(m.Subsystems) == 0 {
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return "", fmt.Errorf("no subsystem for mount")
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}
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return getControllerPath(m.Subsystems[0], cgroups)
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}
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func getCgroupMountsHelper(ss map[string]bool, mi io.Reader, all bool) ([]Mount, error) {
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res := make([]Mount, 0, len(ss))
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scanner := bufio.NewScanner(mi)
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numFound := 0
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for scanner.Scan() && numFound < len(ss) {
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txt := scanner.Text()
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sepIdx := strings.Index(txt, " - ")
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if sepIdx == -1 {
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return nil, fmt.Errorf("invalid mountinfo format")
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}
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if txt[sepIdx+3:sepIdx+10] == "cgroup2" || txt[sepIdx+3:sepIdx+9] != "cgroup" {
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continue
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}
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fields := strings.Split(txt, " ")
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m := Mount{
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Mountpoint: fields[4],
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Root: fields[3],
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}
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for _, opt := range strings.Split(fields[len(fields)-1], ",") {
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seen, known := ss[opt]
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if !known || (!all && seen) {
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continue
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}
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ss[opt] = true
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if strings.HasPrefix(opt, CgroupNamePrefix) {
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opt = opt[len(CgroupNamePrefix):]
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}
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m.Subsystems = append(m.Subsystems, opt)
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numFound++
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}
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if len(m.Subsystems) > 0 || all {
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res = append(res, m)
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}
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}
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if err := scanner.Err(); err != nil {
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return nil, err
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}
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return res, nil
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}
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func getCgroupMountsV1(all bool) ([]Mount, error) {
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f, err := os.Open("/proc/self/mountinfo")
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if err != nil {
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return nil, err
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}
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defer f.Close()
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allSubsystems, err := ParseCgroupFile("/proc/self/cgroup")
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if err != nil {
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return nil, err
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}
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allMap := make(map[string]bool)
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for s := range allSubsystems {
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allMap[s] = false
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}
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return getCgroupMountsHelper(allMap, f, all)
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}
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// GetOwnCgroup returns the relative path to the cgroup docker is running in.
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func GetOwnCgroup(subsystem string) (string, error) {
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if IsCgroup2UnifiedMode() {
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return "", errUnified
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}
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cgroups, err := ParseCgroupFile("/proc/self/cgroup")
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if err != nil {
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return "", err
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}
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return getControllerPath(subsystem, cgroups)
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}
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func GetOwnCgroupPath(subsystem string) (string, error) {
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cgroup, err := GetOwnCgroup(subsystem)
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if err != nil {
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return "", err
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}
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return getCgroupPathHelper(subsystem, cgroup)
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}
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func GetInitCgroup(subsystem string) (string, error) {
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if IsCgroup2UnifiedMode() {
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return "", errUnified
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}
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cgroups, err := ParseCgroupFile("/proc/1/cgroup")
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if err != nil {
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return "", err
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}
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return getControllerPath(subsystem, cgroups)
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}
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func GetInitCgroupPath(subsystem string) (string, error) {
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cgroup, err := GetInitCgroup(subsystem)
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if err != nil {
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return "", err
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}
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return getCgroupPathHelper(subsystem, cgroup)
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}
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func getCgroupPathHelper(subsystem, cgroup string) (string, error) {
|
||||
mnt, root, err := FindCgroupMountpointAndRoot("", subsystem)
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
|
||||
// This is needed for nested containers, because in /proc/self/cgroup we
|
||||
// see paths from host, which don't exist in container.
|
||||
relCgroup, err := filepath.Rel(root, cgroup)
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
|
||||
return filepath.Join(mnt, relCgroup), nil
|
||||
}
|
||||
|
||||
func getControllerPath(subsystem string, cgroups map[string]string) (string, error) {
|
||||
if IsCgroup2UnifiedMode() {
|
||||
return "", errUnified
|
||||
}
|
||||
|
||||
if p, ok := cgroups[subsystem]; ok {
|
||||
return p, nil
|
||||
}
|
||||
|
||||
if p, ok := cgroups[CgroupNamePrefix+subsystem]; ok {
|
||||
return p, nil
|
||||
}
|
||||
|
||||
return "", NewNotFoundError(subsystem)
|
||||
}
|
||||
Loading…
Reference in New Issue