pids.go

Documentation: github.com/opencontainers/runc/libcontainer/cgroups/fs2

     1  package fs2
     2  
     3  import (
     4  	"errors"
     5  	"math"
     6  	"os"
     7  	"strings"
     8  
     9  	"golang.org/x/sys/unix"
    10  
    11  	"github.com/opencontainers/runc/libcontainer/cgroups"
    12  	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
    13  	"github.com/opencontainers/runc/libcontainer/configs"
    14  )
    15  
    16  func isPidsSet(r *configs.Resources) bool {
    17  	return r.PidsLimit != 0
    18  }
    19  
    20  func setPids(dirPath string, r *configs.Resources) error {
    21  	if !isPidsSet(r) {
    22  		return nil
    23  	}
    24  	if val := numToStr(r.PidsLimit); val != "" {
    25  		if err := cgroups.WriteFile(dirPath, "pids.max", val); err != nil {
    26  			return err
    27  		}
    28  	}
    29  
    30  	return nil
    31  }
    32  
    33  func statPidsFromCgroupProcs(dirPath string, stats *cgroups.Stats) error {
    34  	// if the controller is not enabled, let's read PIDS from cgroups.procs
    35  	// (or threads if cgroup.threads is enabled)
    36  	contents, err := cgroups.ReadFile(dirPath, "cgroup.procs")
    37  	if errors.Is(err, unix.ENOTSUP) {
    38  		contents, err = cgroups.ReadFile(dirPath, "cgroup.threads")
    39  	}
    40  	if err != nil {
    41  		return err
    42  	}
    43  	pids := strings.Count(contents, "\n")
    44  	stats.PidsStats.Current = uint64(pids)
    45  	stats.PidsStats.Limit = 0
    46  	return nil
    47  }
    48  
    49  func statPids(dirPath string, stats *cgroups.Stats) error {
    50  	current, err := fscommon.GetCgroupParamUint(dirPath, "pids.current")
    51  	if err != nil {
    52  		if os.IsNotExist(err) {
    53  			return statPidsFromCgroupProcs(dirPath, stats)
    54  		}
    55  		return err
    56  	}
    57  
    58  	max, err := fscommon.GetCgroupParamUint(dirPath, "pids.max")
    59  	if err != nil {
    60  		return err
    61  	}
    62  	// If no limit is set, read from pids.max returns "max", which is
    63  	// converted to MaxUint64 by GetCgroupParamUint. Historically, we
    64  	// represent "no limit" for pids as 0, thus this conversion.
    65  	if max == math.MaxUint64 {
    66  		max = 0
    67  	}
    68  
    69  	stats.PidsStats.Current = current
    70  	stats.PidsStats.Limit = max
    71  	return nil
    72  }
    73
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