mirror of
https://github.com/ceph/ceph-csi.git
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122 lines
2.7 KiB
Go
122 lines
2.7 KiB
Go
/*
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Copyright 2019 The Ceph-CSI 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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package util
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import (
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"bufio"
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"fmt"
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"io"
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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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procCgroup = "/proc/self/cgroup"
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sysPidsMaxFmt = "/sys/fs/cgroup/pids%s/pids.max"
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)
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// return the cgouprs "pids.max" file of the current process
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//
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// find the line containing the pids group from the /proc/self/cgroup file
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// $ grep 'pids' /proc/self/cgroup
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// 7:pids:/kubepods.slice/kubepods-besteffort.slice/....scope
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// $ cat /sys/fs/cgroup/pids + *.scope + /pids.max.
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func getCgroupPidsFile() (string, error) {
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cgroup, err := os.Open(procCgroup)
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if err != nil {
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return "", err
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}
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defer cgroup.Close() // #nosec: error on close is not critical here
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scanner := bufio.NewScanner(cgroup)
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var slice string
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for scanner.Scan() {
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parts := strings.Split(scanner.Text(), ":")
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if parts == nil || len(parts) < 3 {
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continue
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}
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if parts[1] == "pids" {
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slice = parts[2]
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break
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}
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}
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if slice == "" {
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return "", fmt.Errorf("could not find a cgroup for 'pids'")
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}
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pidsMax := fmt.Sprintf(sysPidsMaxFmt, slice)
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return pidsMax, nil
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}
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// GetPIDLimit returns the current PID limit, or an error. A value of -1
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// translates to "max".
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func GetPIDLimit() (int, error) {
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pidsMax, err := getCgroupPidsFile()
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if err != nil {
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return 0, err
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}
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f, err := os.Open(pidsMax) // #nosec - intended reading from /sys/...
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if err != nil {
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return 0, err
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}
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defer f.Close() // #nosec: error on close is not critical here
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maxPidsStr, err := bufio.NewReader(f).ReadString('\n')
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if err != nil && err != io.EOF {
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return 0, err
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}
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maxPidsStr = strings.TrimRight(maxPidsStr, "\n")
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maxPids := -1
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if maxPidsStr != "max" {
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maxPids, err = strconv.Atoi(maxPidsStr)
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if err != nil {
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return 0, err
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}
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}
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return maxPids, nil
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}
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// SetPIDLimit configures the given PID limit for the current process. A value
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// of -1 translates to "max".
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func SetPIDLimit(limit int) error {
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limitStr := "max"
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if limit != -1 {
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limitStr = fmt.Sprintf("%d", limit)
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}
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pidsMax, err := getCgroupPidsFile()
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if err != nil {
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return err
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}
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f, err := os.Create(pidsMax)
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if err != nil {
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return err
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}
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_, err = f.WriteString(limitStr)
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if err != nil {
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f.Close() // #nosec: a write error will be more useful to return
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return err
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}
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return f.Close()
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}
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