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|
package cgroups
import (
"bytes"
"errors"
"fmt"
"os"
"path/filepath"
"strconv"
"strings"
)
var TestMode bool
func cleanString(s string) string {
return strings.Trim(s, "\n")
}
func readAcct(ctr *CgroupControl, name string) (uint64, error) {
p := filepath.Join(ctr.getCgroupv1Path(CPUAcct), name)
return readFileAsUint64(p)
}
func readAcctList(ctr *CgroupControl, name string) ([]uint64, error) {
p := filepath.Join(ctr.getCgroupv1Path(CPUAcct), name)
data, err := os.ReadFile(p)
if err != nil {
return nil, err
}
r := []uint64{}
for _, s := range strings.Split(string(data), " ") {
s = cleanString(s)
if s == "" {
break
}
v, err := strconv.ParseUint(s, 10, 64)
if err != nil {
return nil, fmt.Errorf("parsing %s: %w", s, err)
}
r = append(r, v)
}
return r, nil
}
// GetSystemCPUUsage returns the system usage for all the cgroups
func GetSystemCPUUsage() (uint64, error) {
cgroupv2, err := IsCgroup2UnifiedMode()
if err != nil {
return 0, err
}
if !cgroupv2 {
p := filepath.Join(cgroupRoot, CPUAcct, "cpuacct.usage")
return readFileAsUint64(p)
}
files, err := os.ReadDir(cgroupRoot)
if err != nil {
return 0, err
}
var total uint64
for _, file := range files {
if !file.IsDir() {
continue
}
p := filepath.Join(cgroupRoot, file.Name(), "cpu.stat")
values, err := readCgroupMapPath(p)
if err != nil {
return 0, err
}
if val, found := values["usage_usec"]; found {
v, err := strconv.ParseUint(cleanString(val[0]), 10, 64)
if err != nil {
return 0, err
}
total += v * 1000
}
}
return total, nil
}
func cpusetCopyFileFromParent(dir, file string, cgroupv2 bool) ([]byte, error) {
if dir == cgroupRoot {
return nil, fmt.Errorf("could not find parent to initialize cpuset %s", file)
}
path := filepath.Join(dir, file)
parentPath := path
if cgroupv2 {
parentPath = fmt.Sprintf("%s.effective", parentPath)
}
data, err := os.ReadFile(parentPath)
if err != nil {
// if the file doesn't exist, it is likely that the cpuset controller
// is not enabled in the kernel.
if os.IsNotExist(err) {
return nil, nil
}
return nil, err
}
if strings.Trim(string(data), "\n") != "" {
return data, nil
}
data, err = cpusetCopyFileFromParent(filepath.Dir(dir), file, cgroupv2)
if err != nil {
return nil, err
}
if err := os.WriteFile(path, data, 0o644); err != nil {
return nil, fmt.Errorf("write %s: %w", path, err)
}
return data, nil
}
func cpusetCopyFromParent(path string, cgroupv2 bool) error {
for _, file := range []string{"cpuset.cpus", "cpuset.mems"} {
if _, err := cpusetCopyFileFromParent(path, file, cgroupv2); err != nil {
return err
}
}
return nil
}
// createCgroupv2Path creates the cgroupv2 path and enables all the available controllers
func createCgroupv2Path(path string) (deferredError error) {
if !strings.HasPrefix(path, cgroupRoot+"/") {
return fmt.Errorf("invalid cgroup path %s", path)
}
content, err := os.ReadFile(cgroupRoot + "/cgroup.controllers")
if err != nil {
return err
}
ctrs := bytes.Fields(content)
res := append([]byte("+"), bytes.Join(ctrs, []byte(" +"))...)
current := "/sys/fs"
elements := strings.Split(path, "/")
for i, e := range elements[3:] {
current = filepath.Join(current, e)
if i > 0 {
if err := os.Mkdir(current, 0o755); err != nil {
if !os.IsExist(err) {
return err
}
} else {
// If the directory was created, be sure it is not left around on errors.
defer func() {
if deferredError != nil {
os.Remove(current)
}
}()
}
}
// We enable the controllers for all the path components except the last one. It is not allowed to add
// PIDs if there are already enabled controllers.
if i < len(elements[3:])-1 {
if err := os.WriteFile(filepath.Join(current, "cgroup.subtree_control"), res, 0o755); err != nil {
return err
}
}
}
return nil
}
func (c *CgroupControl) createCgroupDirectory(controller string) (bool, error) {
cPath := c.getCgroupv1Path(controller)
_, err := os.Stat(cPath)
if err == nil {
return false, nil
}
if !errors.Is(err, os.ErrNotExist) {
return false, err
}
if err := os.MkdirAll(cPath, 0o755); err != nil {
return false, fmt.Errorf("creating cgroup for %s: %w", controller, err)
}
return true, nil
}
|
