/usr/share/gocode/src/github.com/opencontainers/runc/libcontainer/cgroups/utils.go is in golang-github-opencontainers-runc-dev 0.0.8+dfsg-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 | // +build linux
package cgroups
import (
"bufio"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"time"
"github.com/docker/go-units"
)
const cgroupNamePrefix = "name="
// https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt
func FindCgroupMountpoint(subsystem string) (string, error) {
// We are not using mount.GetMounts() because it's super-inefficient,
// parsing it directly sped up x10 times because of not using Sscanf.
// It was one of two major performance drawbacks in container start.
f, err := os.Open("/proc/self/mountinfo")
if err != nil {
return "", err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
txt := scanner.Text()
fields := strings.Split(txt, " ")
for _, opt := range strings.Split(fields[len(fields)-1], ",") {
if opt == subsystem {
return fields[4], nil
}
}
}
if err := scanner.Err(); err != nil {
return "", err
}
return "", NewNotFoundError(subsystem)
}
func FindCgroupMountpointAndRoot(subsystem string) (string, string, error) {
f, err := os.Open("/proc/self/mountinfo")
if err != nil {
return "", "", err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
txt := scanner.Text()
fields := strings.Split(txt, " ")
for _, opt := range strings.Split(fields[len(fields)-1], ",") {
if opt == subsystem {
return fields[4], fields[3], nil
}
}
}
if err := scanner.Err(); err != nil {
return "", "", err
}
return "", "", NewNotFoundError(subsystem)
}
func FindCgroupMountpointDir() (string, error) {
f, err := os.Open("/proc/self/mountinfo")
if err != nil {
return "", err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
text := scanner.Text()
fields := strings.Split(text, " ")
// Safe as mountinfo encodes mountpoints with spaces as \040.
index := strings.Index(text, " - ")
postSeparatorFields := strings.Fields(text[index+3:])
numPostFields := len(postSeparatorFields)
// This is an error as we can't detect if the mount is for "cgroup"
if numPostFields == 0 {
return "", fmt.Errorf("Found no fields post '-' in %q", text)
}
if postSeparatorFields[0] == "cgroup" {
// Check that the mount is properly formated.
if numPostFields < 3 {
return "", fmt.Errorf("Error found less than 3 fields post '-' in %q", text)
}
return filepath.Dir(fields[4]), nil
}
}
if err := scanner.Err(); err != nil {
return "", err
}
return "", NewNotFoundError("cgroup")
}
type Mount struct {
Mountpoint string
Root string
Subsystems []string
}
func (m Mount) GetThisCgroupDir(cgroups map[string]string) (string, error) {
if len(m.Subsystems) == 0 {
return "", fmt.Errorf("no subsystem for mount")
}
return getControllerPath(m.Subsystems[0], cgroups)
}
func getCgroupMountsHelper(ss map[string]bool, mi io.Reader) ([]Mount, error) {
res := make([]Mount, 0, len(ss))
scanner := bufio.NewScanner(mi)
for scanner.Scan() {
txt := scanner.Text()
sepIdx := strings.IndexByte(txt, '-')
if sepIdx == -1 {
return nil, fmt.Errorf("invalid mountinfo format")
}
if txt[sepIdx+2:sepIdx+8] != "cgroup" {
continue
}
fields := strings.Split(txt, " ")
m := Mount{
Mountpoint: fields[4],
Root: fields[3],
}
for _, opt := range strings.Split(fields[len(fields)-1], ",") {
if strings.HasPrefix(opt, cgroupNamePrefix) {
m.Subsystems = append(m.Subsystems, opt[len(cgroupNamePrefix):])
}
if ss[opt] {
m.Subsystems = append(m.Subsystems, opt)
}
}
res = append(res, m)
}
if err := scanner.Err(); err != nil {
return nil, err
}
return res, nil
}
func GetCgroupMounts() ([]Mount, error) {
f, err := os.Open("/proc/self/mountinfo")
if err != nil {
return nil, err
}
defer f.Close()
all, err := GetAllSubsystems()
if err != nil {
return nil, err
}
allMap := make(map[string]bool)
for _, s := range all {
allMap[s] = true
}
return getCgroupMountsHelper(allMap, f)
}
// Returns all the cgroup subsystems supported by the kernel
func GetAllSubsystems() ([]string, error) {
f, err := os.Open("/proc/cgroups")
if err != nil {
return nil, err
}
defer f.Close()
subsystems := []string{}
s := bufio.NewScanner(f)
for s.Scan() {
if err := s.Err(); err != nil {
return nil, err
}
text := s.Text()
if text[0] != '#' {
parts := strings.Fields(text)
if len(parts) >= 4 && parts[3] != "0" {
subsystems = append(subsystems, parts[0])
}
}
}
return subsystems, nil
}
// Returns the relative path to the cgroup docker is running in.
func GetThisCgroupDir(subsystem string) (string, error) {
cgroups, err := ParseCgroupFile("/proc/self/cgroup")
if err != nil {
return "", err
}
return getControllerPath(subsystem, cgroups)
}
func GetInitCgroupDir(subsystem string) (string, error) {
cgroups, err := ParseCgroupFile("/proc/1/cgroup")
if err != nil {
return "", err
}
return getControllerPath(subsystem, cgroups)
}
func readProcsFile(dir string) ([]int, error) {
f, err := os.Open(filepath.Join(dir, "cgroup.procs"))
if err != nil {
return nil, err
}
defer f.Close()
var (
s = bufio.NewScanner(f)
out = []int{}
)
for s.Scan() {
if t := s.Text(); t != "" {
pid, err := strconv.Atoi(t)
if err != nil {
return nil, err
}
out = append(out, pid)
}
}
return out, nil
}
func ParseCgroupFile(path string) (map[string]string, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
defer f.Close()
s := bufio.NewScanner(f)
cgroups := make(map[string]string)
for s.Scan() {
if err := s.Err(); err != nil {
return nil, err
}
text := s.Text()
parts := strings.Split(text, ":")
for _, subs := range strings.Split(parts[1], ",") {
cgroups[subs] = parts[2]
}
}
return cgroups, nil
}
func getControllerPath(subsystem string, cgroups map[string]string) (string, error) {
if p, ok := cgroups[subsystem]; ok {
return p, nil
}
if p, ok := cgroups[cgroupNamePrefix+subsystem]; ok {
return p, nil
}
return "", NewNotFoundError(subsystem)
}
func PathExists(path string) bool {
if _, err := os.Stat(path); err != nil {
return false
}
return true
}
func EnterPid(cgroupPaths map[string]string, pid int) error {
for _, path := range cgroupPaths {
if PathExists(path) {
if err := ioutil.WriteFile(filepath.Join(path, "cgroup.procs"),
[]byte(strconv.Itoa(pid)), 0700); err != nil {
return err
}
}
}
return nil
}
// RemovePaths iterates over the provided paths removing them.
// We trying to remove all paths five times with increasing delay between tries.
// If after all there are not removed cgroups - appropriate error will be
// returned.
func RemovePaths(paths map[string]string) (err error) {
delay := 10 * time.Millisecond
for i := 0; i < 5; i++ {
if i != 0 {
time.Sleep(delay)
delay *= 2
}
for s, p := range paths {
os.RemoveAll(p)
// TODO: here probably should be logging
_, err := os.Stat(p)
// We need this strange way of checking cgroups existence because
// RemoveAll almost always returns error, even on already removed
// cgroups
if os.IsNotExist(err) {
delete(paths, s)
}
}
if len(paths) == 0 {
return nil
}
}
return fmt.Errorf("Failed to remove paths: %s", paths)
}
func GetHugePageSize() ([]string, error) {
var pageSizes []string
sizeList := []string{"B", "kB", "MB", "GB", "TB", "PB"}
files, err := ioutil.ReadDir("/sys/kernel/mm/hugepages")
if err != nil {
return pageSizes, err
}
for _, st := range files {
nameArray := strings.Split(st.Name(), "-")
pageSize, err := units.RAMInBytes(nameArray[1])
if err != nil {
return []string{}, err
}
sizeString := units.CustomSize("%g%s", float64(pageSize), 1024.0, sizeList)
pageSizes = append(pageSizes, sizeString)
}
return pageSizes, nil
}
// GetPids returns all pids, that were added to cgroup at path.
func GetPids(path string) ([]int, error) {
return readProcsFile(path)
}
// GetAllPids returns all pids, that were added to cgroup at path and to all its
// subcgroups.
func GetAllPids(path string) ([]int, error) {
var pids []int
// collect pids from all sub-cgroups
err := filepath.Walk(path, func(p string, info os.FileInfo, iErr error) error {
dir, file := filepath.Split(p)
if file != "cgroup.procs" {
return nil
}
if iErr != nil {
return iErr
}
cPids, err := readProcsFile(dir)
if err != nil {
return err
}
pids = append(pids, cPids...)
return nil
})
return pids, err
}
|