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https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
Merge pull request #3310 from pnasrat/cgroups-subpackage
Extract cgroups utilities to own submodule.
This commit is contained in:
commit
4f31141e13
8 changed files with 175 additions and 95 deletions
1
cgroups/MAINTAINERS
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1
cgroups/MAINTAINERS
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@ -0,0 +1 @@
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Michael Crosby <michael@crosbymichael.com> (@crosbymichael)
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101
cgroups/cgroups.go
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101
cgroups/cgroups.go
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@ -0,0 +1,101 @@
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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/mount"
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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"strconv"
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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 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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if parts[1] == subsystem {
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return parts[2], nil
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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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// Returns a list of pids for the given container.
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func GetPidsForContainer(id string) ([]int, error) {
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pids := []int{}
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// memory is chosen randomly, any cgroup used by docker works
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subsystem := "memory"
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cgroupRoot, err := FindCgroupMountpoint(subsystem)
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if err != nil {
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return pids, err
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}
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cgroupDir, err := getThisCgroupDir(subsystem)
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if err != nil {
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return pids, err
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}
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filename := filepath.Join(cgroupRoot, cgroupDir, id, "tasks")
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if _, err := os.Stat(filename); os.IsNotExist(err) {
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// With more recent lxc versions use, cgroup will be in lxc/
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filename = filepath.Join(cgroupRoot, cgroupDir, "lxc", id, "tasks")
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}
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output, err := ioutil.ReadFile(filename)
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if err != nil {
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return pids, err
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}
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for _, p := range strings.Split(string(output), "\n") {
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if len(p) == 0 {
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continue
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}
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pid, err := strconv.Atoi(p)
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if err != nil {
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return pids, fmt.Errorf("Invalid pid '%s': %s", p, err)
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}
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pids = append(pids, pid)
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}
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return pids, nil
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}
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27
cgroups/cgroups_test.go
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27
cgroups/cgroups_test.go
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@ -0,0 +1,27 @@
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package cgroups
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import (
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"bytes"
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"testing"
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)
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const (
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cgroupsContents = `11:hugetlb:/
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10:perf_event:/
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9:blkio:/
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8:net_cls:/
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7:freezer:/
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6:devices:/
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5:memory:/
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4:cpuacct,cpu:/
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3:cpuset:/
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2:name=systemd:/user.slice/user-1000.slice/session-16.scope`
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)
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func TestParseCgroups(t *testing.T) {
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r := bytes.NewBuffer([]byte(cgroupsContents))
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_, err := parseCgroupFile("blkio", r)
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if err != nil {
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t.Fatal(err)
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}
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}
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@ -4,6 +4,10 @@ import (
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"time"
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)
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func GetMounts() ([]*MountInfo, error) {
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return parseMountTable()
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}
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// Looks at /proc/self/mountinfo to determine of the specified
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// mountpoint has been mounted
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func Mounted(mountpoint string) (bool, error) {
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@ -14,7 +18,7 @@ func Mounted(mountpoint string) (bool, error) {
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// Search the table for the mountpoint
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for _, e := range entries {
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if e.mountpoint == mountpoint {
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if e.Mountpoint == mountpoint {
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return true, nil
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}
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}
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@ -5,22 +5,35 @@ import (
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"fmt"
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"io"
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"os"
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"strings"
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)
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const (
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// We only parse upto the mountinfo because that is all we
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// care about right now
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mountinfoFormat = "%d %d %d:%d %s %s %s"
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/* 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
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(1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
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(1) mount ID: unique identifier of the mount (may be reused after umount)
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(2) parent ID: ID of parent (or of self for the top of the mount tree)
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(3) major:minor: value of st_dev for files on filesystem
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(4) root: root of the mount within the filesystem
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(5) mount point: mount point relative to the process's root
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(6) mount options: per mount options
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(7) optional fields: zero or more fields of the form "tag[:value]"
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(8) separator: marks the end of the optional fields
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(9) filesystem type: name of filesystem of the form "type[.subtype]"
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(10) mount source: filesystem specific information or "none"
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(11) super options: per super block options*/
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mountinfoFormat = "%d %d %d:%d %s %s %s "
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)
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// Represents one line from /proc/self/mountinfo
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type procEntry struct {
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id, parent, major, minor int
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source, mountpoint, opts string
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type MountInfo struct {
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Id, Parent, Major, Minor int
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Root, Mountpoint, Opts string
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Fstype, Source, VfsOpts string
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}
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// Parse /proc/self/mountinfo because comparing Dev and ino does not work from bind mounts
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func parseMountTable() ([]*procEntry, error) {
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func parseMountTable() ([]*MountInfo, 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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@ -30,10 +43,10 @@ func parseMountTable() ([]*procEntry, error) {
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return parseInfoFile(f)
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}
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func parseInfoFile(r io.Reader) ([]*procEntry, error) {
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func parseInfoFile(r io.Reader) ([]*MountInfo, error) {
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var (
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s = bufio.NewScanner(r)
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out = []*procEntry{}
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out = []*MountInfo{}
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)
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for s.Scan() {
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}
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var (
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p = &procEntry{}
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p = &MountInfo{}
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text = s.Text()
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)
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if _, err := fmt.Sscanf(text, mountinfoFormat,
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&p.id, &p.parent, &p.major, &p.minor,
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&p.source, &p.mountpoint, &p.opts); err != nil {
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&p.Id, &p.Parent, &p.Major, &p.Minor,
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&p.Root, &p.Mountpoint, &p.Opts); err != nil {
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return nil, fmt.Errorf("Scanning '%s' failed: %s", text, err)
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}
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// Safe as mountinfo encodes mountpoints with spaces as \040.
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index := strings.Index(text, " - ")
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postSeparatorFields := strings.Fields(text[index+3:])
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if len(postSeparatorFields) != 3 {
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return nil, fmt.Errorf("Error did not find 3 fields post '-' in '%s'", text)
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}
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p.Fstype = postSeparatorFields[0]
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p.Source = postSeparatorFields[1]
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p.VfsOpts = postSeparatorFields[2]
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out = append(out, p)
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}
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return out, nil
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@ -4,11 +4,12 @@ import (
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"container/list"
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"fmt"
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"github.com/dotcloud/docker/archive"
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"github.com/dotcloud/docker/pkg/graphdb"
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"github.com/dotcloud/docker/cgroups"
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"github.com/dotcloud/docker/graphdriver"
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"github.com/dotcloud/docker/graphdriver/aufs"
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_ "github.com/dotcloud/docker/graphdriver/devmapper"
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_ "github.com/dotcloud/docker/graphdriver/vfs"
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"github.com/dotcloud/docker/pkg/graphdb"
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"github.com/dotcloud/docker/utils"
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"io"
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"io/ioutil"
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@ -332,7 +333,7 @@ func (runtime *Runtime) restore() error {
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// FIXME: comment please!
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func (runtime *Runtime) UpdateCapabilities(quiet bool) {
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if cgroupMemoryMountpoint, err := utils.FindCgroupMountpoint("memory"); err != nil {
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if cgroupMemoryMountpoint, err := cgroups.FindCgroupMountpoint("memory"); err != nil {
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if !quiet {
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log.Printf("WARNING: %s\n", err)
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}
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@ -6,6 +6,7 @@ import (
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"fmt"
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"github.com/dotcloud/docker/archive"
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"github.com/dotcloud/docker/auth"
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"github.com/dotcloud/docker/cgroups"
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"github.com/dotcloud/docker/engine"
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"github.com/dotcloud/docker/pkg/graphdb"
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"github.com/dotcloud/docker/registry"
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@ -702,7 +703,7 @@ func (srv *Server) ContainerTop(name, psArgs string) (*APITop, error) {
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if !container.State.IsRunning() {
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return nil, fmt.Errorf("Container %s is not running", name)
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}
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pids, err := utils.GetPidsForContainer(container.ID)
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pids, err := cgroups.GetPidsForContainer(container.ID)
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if err != nil {
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return nil, err
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}
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@ -583,28 +583,6 @@ func CompareKernelVersion(a, b *KernelVersionInfo) int {
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return 0
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}
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func FindCgroupMountpoint(cgroupType string) (string, error) {
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output, err := ioutil.ReadFile("/proc/mounts")
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if err != nil {
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return "", err
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}
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// /proc/mounts has 6 fields per line, one mount per line, e.g.
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// cgroup /sys/fs/cgroup/devices cgroup rw,relatime,devices 0 0
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for _, line := range strings.Split(string(output), "\n") {
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parts := strings.Split(line, " ")
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if len(parts) == 6 && parts[2] == "cgroup" {
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for _, opt := range strings.Split(parts[3], ",") {
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if opt == cgroupType {
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return parts[1], 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", cgroupType)
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}
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func GetKernelVersion() (*KernelVersionInfo, error) {
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var (
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err error
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@ -1157,59 +1135,3 @@ func CopyFile(src, dst string) (int64, error) {
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defer df.Close()
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return io.Copy(df, sf)
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}
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// Returns the relative path to the cgroup docker is running in.
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func GetThisCgroup(cgroupType string) (string, error) {
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output, err := ioutil.ReadFile("/proc/self/cgroup")
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if err != nil {
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return "", err
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}
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for _, line := range strings.Split(string(output), "\n") {
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parts := strings.Split(line, ":")
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// any type used by docker should work
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if parts[1] == cgroupType {
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return parts[2], nil
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}
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}
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return "", fmt.Errorf("cgroup '%s' not found in /proc/self/cgroup", cgroupType)
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}
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// Returns a list of pids for the given container.
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func GetPidsForContainer(id string) ([]int, error) {
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pids := []int{}
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// memory is chosen randomly, any cgroup used by docker works
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cgroupType := "memory"
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cgroupRoot, err := FindCgroupMountpoint(cgroupType)
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if err != nil {
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return pids, err
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}
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cgroupThis, err := GetThisCgroup(cgroupType)
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if err != nil {
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return pids, err
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}
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filename := filepath.Join(cgroupRoot, cgroupThis, id, "tasks")
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if _, err := os.Stat(filename); os.IsNotExist(err) {
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// With more recent lxc versions use, cgroup will be in lxc/
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filename = filepath.Join(cgroupRoot, cgroupThis, "lxc", id, "tasks")
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}
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output, err := ioutil.ReadFile(filename)
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if err != nil {
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return pids, err
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}
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for _, p := range strings.Split(string(output), "\n") {
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if len(p) == 0 {
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continue
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}
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pid, err := strconv.Atoi(p)
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if err != nil {
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return pids, fmt.Errorf("Invalid pid '%s': %s", p, err)
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}
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pids = append(pids, pid)
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}
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return pids, nil
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}
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