104 lines
2.7 KiB
Go
104 lines
2.7 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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"io/ioutil"
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"os"
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"path/filepath"
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"strings"
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)
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type Cgroup struct {
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Name string `json:"name,omitempty"`
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Parent string `json:"parent,omitempty"`
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DeviceAccess bool `json:"device_access,omitempty"` // name of parent cgroup or slice
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Memory int64 `json:"memory,omitempty"` // Memory limit (in bytes)
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MemorySwap int64 `json:"memory_swap,omitempty"` // Total memory usage (memory + swap); set `-1' to disable swap
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CpuShares int64 `json:"cpu_shares,omitempty"` // CPU shares (relative weight vs. other containers)
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CpusetCpus string `json:"cpuset_cpus,omitempty"` // CPU to use
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UnitProperties [][2]string `json:"unit_properties,omitempty"` // systemd unit properties
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}
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type ActiveCgroup interface {
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Cleanup() error
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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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func writeFile(dir, file, data string) error {
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return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
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}
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func (c *Cgroup) Apply(pid int) (ActiveCgroup, error) {
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// We have two implementation of cgroups support, one is based on
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// systemd and the dbus api, and one is based on raw cgroup fs operations
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// following the pre-single-writer model docs at:
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// http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups/
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if useSystemd() {
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return systemdApply(c, pid)
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} else {
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return rawApply(c, pid)
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}
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}
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