cubefs

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// 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("at least 4 fields required, found %d fields in cgroup info string: %s", 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("failed to parse hierarchy ID")
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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("failed to parse Cgroup Num")
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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("failed to parse Enabled")
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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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