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|
package fs
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"github.com/docker/libcontainer/cgroups"
)
var (
subsystems = map[string]subsystem{
"devices": &devicesGroup{},
"memory": &memoryGroup{},
"cpu": &cpuGroup{},
"cpuset": &cpusetGroup{},
"cpuacct": &cpuacctGroup{},
"blkio": &blkioGroup{},
"perf_event": &perfEventGroup{},
"freezer": &freezerGroup{},
}
)
type subsystem interface {
Set(*data) error
Remove(*data) error
GetStats(*data, *cgroups.Stats) error
}
type data struct {
root string
cgroup string
c *cgroups.Cgroup
pid int
}
func Apply(c *cgroups.Cgroup, pid int) (cgroups.ActiveCgroup, error) {
d, err := getCgroupData(c, pid)
if err != nil {
return nil, err
}
for _, sys := range subsystems {
if err := sys.Set(d); err != nil {
d.Cleanup()
return nil, err
}
}
return d, nil
}
func GetStats(c *cgroups.Cgroup) (*cgroups.Stats, error) {
stats := cgroups.NewStats()
d, err := getCgroupData(c, 0)
if err != nil {
return nil, fmt.Errorf("getting CgroupData %s", err)
}
for sysName, sys := range subsystems {
// Don't fail if a cgroup hierarchy was not found.
if err := sys.GetStats(d, stats); err != nil && err != cgroups.ErrNotFound {
return nil, fmt.Errorf("getting stats for system %q %s", sysName, err)
}
}
return stats, nil
}
// Freeze toggles the container's freezer cgroup depending on the state
// provided
func Freeze(c *cgroups.Cgroup, state cgroups.FreezerState) error {
d, err := getCgroupData(c, 0)
if err != nil {
return err
}
c.Freezer = state
freezer := subsystems["freezer"]
return freezer.Set(d)
}
func GetPids(c *cgroups.Cgroup) ([]int, error) {
d, err := getCgroupData(c, 0)
if err != nil {
return nil, err
}
dir, err := d.path("devices")
if err != nil {
return nil, err
}
return cgroups.ReadProcsFile(dir)
}
func getCgroupData(c *cgroups.Cgroup, pid int) (*data, error) {
// 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)
}
return &data{
root: cgroupRoot,
cgroup: cgroup,
c: c,
pid: pid,
}, nil
}
func (raw *data) parent(subsystem string) (string, error) {
initPath, err := cgroups.GetInitCgroupDir(subsystem)
if err != nil {
return "", err
}
return filepath.Join(raw.root, subsystem, initPath), nil
}
func (raw *data) path(subsystem string) (string, error) {
parent, err := raw.parent(subsystem)
if err != nil {
return "", err
}
return filepath.Join(parent, 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 readFile(dir, file string) (string, error) {
data, err := ioutil.ReadFile(filepath.Join(dir, file))
return string(data), err
}
func removePath(p string, err error) error {
if err != nil {
return err
}
if p != "" {
return os.RemoveAll(p)
}
return nil
}
|
