cloudflared-mirror/vendor/github.com/prometheus/procfs/proc_cgroups.go

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// Copyright 2021 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package procfs
import (
"bufio"
"bytes"
"fmt"
"strconv"
"strings"
"github.com/prometheus/procfs/internal/util"
)
// CgroupSummary models one line from /proc/cgroups.
// This file contains information about the controllers that are compiled into the kernel.
//
// Also see http://man7.org/linux/man-pages/man7/cgroups.7.html
type CgroupSummary struct {
// The name of the controller. controller is also known as subsystem.
SubsysName string
// The unique ID of the cgroup hierarchy on which this controller is mounted.
Hierarchy int
// The number of control groups in this hierarchy using this controller.
Cgroups int
// This field contains the value 1 if this controller is enabled, or 0 if it has been disabled
Enabled int
}
// parseCgroupSummary parses each line of the /proc/cgroup file
// Line format is `subsys_name hierarchy num_cgroups enabled`.
func parseCgroupSummaryString(CgroupSummaryStr string) (*CgroupSummary, error) {
var err error
fields := strings.Fields(CgroupSummaryStr)
// require at least 4 fields
if len(fields) < 4 {
return nil, fmt.Errorf("%w: 4+ fields required, found %d fields in cgroup info string: %s", ErrFileParse, len(fields), CgroupSummaryStr)
}
CgroupSummary := &CgroupSummary{
SubsysName: fields[0],
}
CgroupSummary.Hierarchy, err = strconv.Atoi(fields[1])
if err != nil {
return nil, fmt.Errorf("%w: Unable to parse hierarchy ID from %q", ErrFileParse, fields[1])
}
CgroupSummary.Cgroups, err = strconv.Atoi(fields[2])
if err != nil {
return nil, fmt.Errorf("%w: Unable to parse Cgroup Num from %q", ErrFileParse, fields[2])
}
CgroupSummary.Enabled, err = strconv.Atoi(fields[3])
if err != nil {
return nil, fmt.Errorf("%w: Unable to parse Enabled from %q", ErrFileParse, fields[3])
}
return CgroupSummary, nil
}
// parseCgroupSummary reads each line of the /proc/cgroup file.
func parseCgroupSummary(data []byte) ([]CgroupSummary, error) {
var CgroupSummarys []CgroupSummary
scanner := bufio.NewScanner(bytes.NewReader(data))
for scanner.Scan() {
CgroupSummaryString := scanner.Text()
// ignore comment lines
if strings.HasPrefix(CgroupSummaryString, "#") {
continue
}
CgroupSummary, err := parseCgroupSummaryString(CgroupSummaryString)
if err != nil {
return nil, err
}
CgroupSummarys = append(CgroupSummarys, *CgroupSummary)
}
err := scanner.Err()
return CgroupSummarys, err
}
// CgroupSummarys returns information about current /proc/cgroups.
func (fs FS) CgroupSummarys() ([]CgroupSummary, error) {
data, err := util.ReadFileNoStat(fs.proc.Path("cgroups"))
if err != nil {
return nil, err
}
return parseCgroupSummary(data)
}