mirror of
https://github.com/opencontainers/runc.git
synced 2026-07-11 22:37:14 +08:00
Kir Kolyshkin
1cbfe23464
This was initially added by commits41d9d26513and4a8f0b4db4, apparently to implement docker run --cgroup container:ID, which was never merged. Therefore, this code is not and was never used. It needs to be removed mainly because having it makes it much harder to understand how cgroup manager works (because with this in place we have not one or two but three sets of cgroup paths to think about). Note if the paths are known and there is a need to add a PID to existing cgroup, cgroup manager is not needed at all -- something like cgroups.WriteCgroupProc or cgroups.EnterPid is sufficient (and the latter is what runc exec uses in (*setnsProcess).start). Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
101 lines
2.8 KiB
Go
101 lines
2.8 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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"fmt"
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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/runc/libcontainer/configs"
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libcontainerUtils "github.com/opencontainers/runc/libcontainer/utils"
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)
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const UnifiedMountpoint = "/sys/fs/cgroup"
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func defaultDirPath(c *configs.Cgroup) (string, error) {
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if (c.Name != "" || c.Parent != "") && c.Path != "" {
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return "", fmt.Errorf("cgroup: either Path or Name and Parent should be used, got %+v", c)
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}
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// XXX: Do not remove this code. Path safety is important! -- cyphar
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cgPath := libcontainerUtils.CleanPath(c.Path)
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cgParent := libcontainerUtils.CleanPath(c.Parent)
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cgName := libcontainerUtils.CleanPath(c.Name)
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return _defaultDirPath(UnifiedMountpoint, cgPath, cgParent, cgName)
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}
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func _defaultDirPath(root, cgPath, cgParent, cgName string) (string, error) {
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if (cgName != "" || cgParent != "") && cgPath != "" {
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return "", errors.New("cgroup: either Path or Name and Parent should be used")
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}
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innerPath := cgPath
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if innerPath == "" {
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innerPath = filepath.Join(cgParent, cgName)
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}
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if filepath.IsAbs(innerPath) {
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return filepath.Join(root, innerPath), nil
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}
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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(root, 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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var (
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text = s.Text()
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parts = strings.SplitN(text, ":", 3)
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)
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if len(parts) < 3 {
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return "", fmt.Errorf("invalid cgroup entry: %q", text)
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}
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// text is like "0::/user.slice/user-1001.slice/session-1.scope"
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if parts[0] == "0" && parts[1] == "" {
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return parts[2], 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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