gotosocial/vendor/go.uber.org/automaxprocs/internal/cgroups/subsys.go

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