forked from TrueCloudLab/distribution
98 lines
3.2 KiB
Go
98 lines
3.2 KiB
Go
// Copyright 2021 The Prometheus 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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package procfs
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import (
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"bufio"
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"bytes"
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"fmt"
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"strconv"
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"strings"
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"github.com/prometheus/procfs/internal/util"
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)
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// CgroupSummary models one line from /proc/cgroups.
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// This file contains information about the controllers that are compiled into the kernel.
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//
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// Also see http://man7.org/linux/man-pages/man7/cgroups.7.html
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type CgroupSummary struct {
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// The name of the controller. controller is also known as subsystem.
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SubsysName string
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// The unique ID of the cgroup hierarchy on which this controller is mounted.
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Hierarchy int
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// The number of control groups in this hierarchy using this controller.
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Cgroups int
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// This field contains the value 1 if this controller is enabled, or 0 if it has been disabled
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Enabled int
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}
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// parseCgroupSummary parses each line of the /proc/cgroup file
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// Line format is `subsys_name hierarchy num_cgroups enabled`.
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func parseCgroupSummaryString(CgroupSummaryStr string) (*CgroupSummary, error) {
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var err error
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fields := strings.Fields(CgroupSummaryStr)
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// require at least 4 fields
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if len(fields) < 4 {
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return nil, fmt.Errorf("%w: 4+ fields required, found %d fields in cgroup info string: %s", ErrFileParse, len(fields), CgroupSummaryStr)
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}
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CgroupSummary := &CgroupSummary{
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SubsysName: fields[0],
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}
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CgroupSummary.Hierarchy, err = strconv.Atoi(fields[1])
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if err != nil {
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return nil, fmt.Errorf("%w: Unable to parse hierarchy ID from %q", ErrFileParse, fields[1])
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}
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CgroupSummary.Cgroups, err = strconv.Atoi(fields[2])
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if err != nil {
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return nil, fmt.Errorf("%w: Unable to parse Cgroup Num from %q", ErrFileParse, fields[2])
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}
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CgroupSummary.Enabled, err = strconv.Atoi(fields[3])
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if err != nil {
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return nil, fmt.Errorf("%w: Unable to parse Enabled from %q", ErrFileParse, fields[3])
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}
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return CgroupSummary, nil
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}
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// parseCgroupSummary reads each line of the /proc/cgroup file.
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func parseCgroupSummary(data []byte) ([]CgroupSummary, error) {
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var CgroupSummarys []CgroupSummary
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scanner := bufio.NewScanner(bytes.NewReader(data))
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for scanner.Scan() {
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CgroupSummaryString := scanner.Text()
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// ignore comment lines
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if strings.HasPrefix(CgroupSummaryString, "#") {
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continue
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}
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CgroupSummary, err := parseCgroupSummaryString(CgroupSummaryString)
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if err != nil {
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return nil, err
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}
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CgroupSummarys = append(CgroupSummarys, *CgroupSummary)
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}
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err := scanner.Err()
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return CgroupSummarys, err
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}
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// CgroupSummarys returns information about current /proc/cgroups.
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func (fs FS) CgroupSummarys() ([]CgroupSummary, error) {
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data, err := util.ReadFileNoStat(fs.proc.Path("cgroups"))
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if err != nil {
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return nil, err
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}
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return parseCgroupSummary(data)
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}
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