74 lines
1.8 KiB
Go
74 lines
1.8 KiB
Go
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/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cgroups
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import (
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"bufio"
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"fmt"
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"os"
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"path/filepath"
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"strings"
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)
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// V1 returns all the groups in the default cgroups mountpoint in a single hierarchy
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func V1() ([]Subsystem, error) {
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root, err := v1MountPoint()
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if err != nil {
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return nil, err
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}
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subsystems, err := defaults(root)
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if err != nil {
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return nil, err
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}
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var enabled []Subsystem
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for _, s := range pathers(subsystems) {
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// check and remove the default groups that do not exist
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if _, err := os.Lstat(s.Path("/")); err == nil {
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enabled = append(enabled, s)
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}
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}
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return enabled, nil
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}
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// v1MountPoint returns the mount point where the cgroup
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// mountpoints are mounted in a single hiearchy
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func v1MountPoint() (string, error) {
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f, err := os.Open("/proc/self/mountinfo")
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if err != nil {
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return "", err
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}
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defer f.Close()
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scanner := bufio.NewScanner(f)
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for scanner.Scan() {
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var (
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text = scanner.Text()
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fields = strings.Split(text, " ")
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numFields = len(fields)
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)
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if numFields < 10 {
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return "", fmt.Errorf("mountinfo: bad entry %q", text)
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}
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if fields[numFields-3] == "cgroup" {
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return filepath.Dir(fields[4]), nil
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}
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}
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if err := scanner.Err(); err != nil {
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return "", err
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}
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return "", ErrMountPointNotExist
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}
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