зеркало из https://github.com/microsoft/docker.git
101 строка
2.2 KiB
Go
101 строка
2.2 KiB
Go
package cgroups
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"github.com/dotcloud/docker/pkg/mount"
|
|
"io"
|
|
"io/ioutil"
|
|
"os"
|
|
"path/filepath"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
// https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt
|
|
func FindCgroupMountpoint(subsystem string) (string, error) {
|
|
mounts, err := mount.GetMounts()
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
|
|
for _, mount := range mounts {
|
|
if mount.Fstype == "cgroup" {
|
|
for _, opt := range strings.Split(mount.VfsOpts, ",") {
|
|
if opt == subsystem {
|
|
return mount.Mountpoint, nil
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return "", fmt.Errorf("cgroup mountpoint not found for %s", subsystem)
|
|
}
|
|
|
|
// Returns the relative path to the cgroup docker is running in.
|
|
func getThisCgroupDir(subsystem string) (string, error) {
|
|
f, err := os.Open("/proc/self/cgroup")
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
defer f.Close()
|
|
|
|
return parseCgroupFile(subsystem, f)
|
|
}
|
|
|
|
func parseCgroupFile(subsystem string, r io.Reader) (string, error) {
|
|
s := bufio.NewScanner(r)
|
|
|
|
for s.Scan() {
|
|
if err := s.Err(); err != nil {
|
|
return "", err
|
|
}
|
|
text := s.Text()
|
|
parts := strings.Split(text, ":")
|
|
if parts[1] == subsystem {
|
|
return parts[2], nil
|
|
}
|
|
}
|
|
return "", fmt.Errorf("cgroup '%s' not found in /proc/self/cgroup", subsystem)
|
|
}
|
|
|
|
// Returns a list of pids for the given container.
|
|
func GetPidsForContainer(id string) ([]int, error) {
|
|
pids := []int{}
|
|
|
|
// memory is chosen randomly, any cgroup used by docker works
|
|
subsystem := "memory"
|
|
|
|
cgroupRoot, err := FindCgroupMountpoint(subsystem)
|
|
if err != nil {
|
|
return pids, err
|
|
}
|
|
|
|
cgroupDir, err := getThisCgroupDir(subsystem)
|
|
if err != nil {
|
|
return pids, err
|
|
}
|
|
|
|
filename := filepath.Join(cgroupRoot, cgroupDir, id, "tasks")
|
|
if _, err := os.Stat(filename); os.IsNotExist(err) {
|
|
// With more recent lxc versions use, cgroup will be in lxc/
|
|
filename = filepath.Join(cgroupRoot, cgroupDir, "lxc", id, "tasks")
|
|
}
|
|
|
|
output, err := ioutil.ReadFile(filename)
|
|
if err != nil {
|
|
return pids, err
|
|
}
|
|
for _, p := range strings.Split(string(output), "\n") {
|
|
if len(p) == 0 {
|
|
continue
|
|
}
|
|
pid, err := strconv.Atoi(p)
|
|
if err != nil {
|
|
return pids, fmt.Errorf("Invalid pid '%s': %s", p, err)
|
|
}
|
|
pids = append(pids, pid)
|
|
}
|
|
return pids, nil
|
|
}
|