mirror of
https://github.com/ceph/ceph-csi.git
synced 2025-06-03 04:16:42 +00:00
81 lines
2.1 KiB
Go
81 lines
2.1 KiB
Go
/*
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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 fs2
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import (
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"bufio"
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"errors"
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"io"
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"os"
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"path/filepath"
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"strings"
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"github.com/opencontainers/cgroups"
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"github.com/opencontainers/cgroups/internal/path"
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)
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const UnifiedMountpoint = "/sys/fs/cgroup"
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func defaultDirPath(c *cgroups.Cgroup) (string, error) {
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innerPath, err := path.Inner(c)
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if err != nil {
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return "", err
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}
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if filepath.IsAbs(innerPath) {
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return filepath.Join(UnifiedMountpoint, innerPath), nil
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}
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// we don't need to use /proc/thread-self here because runc always runs
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// with every thread in the same cgroup. This lets us avoid having to do
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// runtime.LockOSThread.
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ownCgroup, err := parseCgroupFile("/proc/self/cgroup")
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if err != nil {
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return "", err
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}
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// The current user scope most probably has tasks in it already,
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// making it impossible to enable controllers for its sub-cgroup.
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// A parent cgroup (with no tasks in it) is what we need.
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ownCgroup = filepath.Dir(ownCgroup)
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return filepath.Join(UnifiedMountpoint, ownCgroup, innerPath), nil
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}
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// parseCgroupFile parses /proc/PID/cgroup file and return string
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func parseCgroupFile(path string) (string, error) {
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f, err := os.Open(path)
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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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return parseCgroupFromReader(f)
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}
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func parseCgroupFromReader(r io.Reader) (string, error) {
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s := bufio.NewScanner(r)
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for s.Scan() {
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// "0::/user.slice/user-1001.slice/session-1.scope"
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if path, ok := strings.CutPrefix(s.Text(), "0::"); ok {
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return path, nil
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}
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}
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if err := s.Err(); err != nil {
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return "", err
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}
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return "", errors.New("cgroup path not found")
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}
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