103 lines
2.8 KiB
Go
103 lines
2.8 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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// +build linux
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package cgroups
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import (
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"bufio"
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"os"
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"strconv"
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"strings"
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)
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const (
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_cgroupSep = ":"
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_cgroupSubsysSep = ","
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)
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const (
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_csFieldIDID = iota
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_csFieldIDSubsystems
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_csFieldIDName
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_csFieldCount
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)
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// CGroupSubsys represents the data structure for entities in
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// `/proc/$PID/cgroup`. See also proc(5) for more information.
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type CGroupSubsys struct {
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ID int
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Subsystems []string
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Name string
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}
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// NewCGroupSubsysFromLine returns a new *CGroupSubsys by parsing a string in
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// the format of `/proc/$PID/cgroup`
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func NewCGroupSubsysFromLine(line string) (*CGroupSubsys, error) {
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fields := strings.SplitN(line, _cgroupSep, _csFieldCount)
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if len(fields) != _csFieldCount {
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return nil, cgroupSubsysFormatInvalidError{line}
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}
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id, err := strconv.Atoi(fields[_csFieldIDID])
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if err != nil {
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return nil, err
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}
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cgroup := &CGroupSubsys{
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ID: id,
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Subsystems: strings.Split(fields[_csFieldIDSubsystems], _cgroupSubsysSep),
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Name: fields[_csFieldIDName],
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}
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return cgroup, nil
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}
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// parseCGroupSubsystems parses procPathCGroup (usually at `/proc/$PID/cgroup`)
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// and returns a new map[string]*CGroupSubsys.
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func parseCGroupSubsystems(procPathCGroup string) (map[string]*CGroupSubsys, error) {
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cgroupFile, err := os.Open(procPathCGroup)
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if err != nil {
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return nil, err
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}
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defer cgroupFile.Close()
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scanner := bufio.NewScanner(cgroupFile)
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subsystems := make(map[string]*CGroupSubsys)
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for scanner.Scan() {
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cgroup, err := NewCGroupSubsysFromLine(scanner.Text())
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if err != nil {
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return nil, err
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}
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for _, subsys := range cgroup.Subsystems {
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subsystems[subsys] = cgroup
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}
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}
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if err := scanner.Err(); err != nil {
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return nil, err
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}
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return subsystems, nil
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}
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