3de41b34a2
This is a minimal version of raw cgroup support for libcontainer. It has only enough for what docker needs, and it has no support for systemd yet. Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
69 lines
1.4 KiB
Go
69 lines
1.4 KiB
Go
package cgroups
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import (
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"bufio"
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"fmt"
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"github.com/dotcloud/docker/pkg/mount"
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"io"
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"os"
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"strings"
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)
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// https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt
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func FindCgroupMountpoint(subsystem string) (string, error) {
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mounts, err := mount.GetMounts()
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if err != nil {
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return "", err
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}
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for _, mount := range mounts {
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if mount.Fstype == "cgroup" {
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for _, opt := range strings.Split(mount.VfsOpts, ",") {
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if opt == subsystem {
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return mount.Mountpoint, nil
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}
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}
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}
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}
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return "", fmt.Errorf("cgroup mountpoint not found for %s", subsystem)
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}
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// Returns the relative path to the cgroup docker is running in.
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func GetThisCgroupDir(subsystem string) (string, error) {
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f, err := os.Open("/proc/self/cgroup")
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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 parseCgroupFile(subsystem, f)
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}
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func GetInitCgroupDir(subsystem string) (string, error) {
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f, err := os.Open("/proc/1/cgroup")
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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 parseCgroupFile(subsystem, f)
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}
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func parseCgroupFile(subsystem string, r io.Reader) (string, error) {
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s := bufio.NewScanner(r)
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for s.Scan() {
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if err := s.Err(); err != nil {
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return "", err
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}
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text := s.Text()
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parts := strings.Split(text, ":")
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for _, subs := range strings.Split(parts[1], ",") {
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if subs == subsystem {
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return parts[2], nil
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}
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}
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}
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return "", fmt.Errorf("cgroup '%s' not found in /proc/self/cgroup", subsystem)
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}
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