pkg/cgroups/fs/apply_raw.go
Michael Crosby 810cf722cc Add remove method to subsystems
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
2014-04-18 22:17:31 -07:00

116 lines
2.2 KiB
Go

package fs
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"github.com/dotcloud/docker/pkg/cgroups"
)
var (
subsystems = []subsystem{
&devicesGroup{},
&memoryGroup{},
&cpuGroup{},
&cpusetGroup{},
&cpuacctGroup{},
&blkioGroup{},
&perfEventGroup{},
&freezerGroup{},
}
)
type subsystem interface {
Set(*data) error
Remove(*data) error
}
type data struct {
root string
cgroup string
c *cgroups.Cgroup
pid int
}
func Apply(c *cgroups.Cgroup, pid int) (cgroups.ActiveCgroup, error) {
// We have two implementation of cgroups support, one is based on
// systemd and the dbus api, and one is based on raw cgroup fs operations
// following the pre-single-writer model docs at:
// http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups/
//
// we can pick any subsystem to find the root
cgroupRoot, err := cgroups.FindCgroupMountpoint("cpu")
if err != nil {
return nil, err
}
cgroupRoot = filepath.Dir(cgroupRoot)
if _, err := os.Stat(cgroupRoot); err != nil {
return nil, fmt.Errorf("cgroups fs not found")
}
cgroup := c.Name
if c.Parent != "" {
cgroup = filepath.Join(c.Parent, cgroup)
}
d := &data{
root: cgroupRoot,
cgroup: cgroup,
c: c,
pid: pid,
}
for _, sys := range subsystems {
if err := sys.Set(d); err != nil {
return nil, err
}
}
return d, nil
}
func (raw *data) path(subsystem string) (string, error) {
initPath, err := cgroups.GetInitCgroupDir(subsystem)
if err != nil {
return "", err
}
return filepath.Join(raw.root, subsystem, initPath, raw.cgroup), nil
}
func (raw *data) join(subsystem string) (string, error) {
path, err := raw.path(subsystem)
if err != nil {
return "", err
}
if err := os.MkdirAll(path, 0755); err != nil && !os.IsExist(err) {
return "", err
}
if err := writeFile(path, "cgroup.procs", strconv.Itoa(raw.pid)); err != nil {
return "", err
}
return path, nil
}
func (raw *data) Cleanup() error {
for _, sys := range subsystems {
sys.Remove(raw)
}
return nil
}
func writeFile(dir, file, data string) error {
return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
}
func removePath(p string, err error) error {
if err != nil {
return err
}
if p != "" {
return os.RemoveAll(p)
}
return nil
}