mirror of
https://github.com/rocky-linux/peridot.git
synced 2024-11-18 19:31:25 +00:00
99 lines
3.6 KiB
Go
99 lines
3.6 KiB
Go
// Copyright 2020 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"
|
|
)
|
|
|
|
// Cgroup models one line from /proc/[pid]/cgroup. Each Cgroup struct describes the the placement of a PID inside a
|
|
// specific control hierarchy. The kernel has two cgroup APIs, v1 and v2. v1 has one hierarchy per available resource
|
|
// controller, while v2 has one unified hierarchy shared by all controllers. Regardless of v1 or v2, all hierarchies
|
|
// contain all running processes, so the question answerable with a Cgroup struct is 'where is this process in
|
|
// this hierarchy' (where==what path on the specific cgroupfs). By prefixing this path with the mount point of
|
|
// *this specific* hierarchy, you can locate the relevant pseudo-files needed to read/set the data for this PID
|
|
// in this hierarchy
|
|
//
|
|
// Also see http://man7.org/linux/man-pages/man7/cgroups.7.html
|
|
type Cgroup struct {
|
|
// HierarchyID that can be matched to a named hierarchy using /proc/cgroups. Cgroups V2 only has one
|
|
// hierarchy, so HierarchyID is always 0. For cgroups v1 this is a unique ID number
|
|
HierarchyID int
|
|
// Controllers using this hierarchy of processes. Controllers are also known as subsystems. For
|
|
// Cgroups V2 this may be empty, as all active controllers use the same hierarchy
|
|
Controllers []string
|
|
// Path of this control group, relative to the mount point of the cgroupfs representing this specific
|
|
// hierarchy
|
|
Path string
|
|
}
|
|
|
|
// parseCgroupString parses each line of the /proc/[pid]/cgroup file
|
|
// Line format is hierarchyID:[controller1,controller2]:path.
|
|
func parseCgroupString(cgroupStr string) (*Cgroup, error) {
|
|
var err error
|
|
|
|
fields := strings.SplitN(cgroupStr, ":", 3)
|
|
if len(fields) < 3 {
|
|
return nil, fmt.Errorf("at least 3 fields required, found %d fields in cgroup string: %s", len(fields), cgroupStr)
|
|
}
|
|
|
|
cgroup := &Cgroup{
|
|
Path: fields[2],
|
|
Controllers: nil,
|
|
}
|
|
cgroup.HierarchyID, err = strconv.Atoi(fields[0])
|
|
if err != nil {
|
|
return nil, fmt.Errorf("failed to parse hierarchy ID")
|
|
}
|
|
if fields[1] != "" {
|
|
ssNames := strings.Split(fields[1], ",")
|
|
cgroup.Controllers = append(cgroup.Controllers, ssNames...)
|
|
}
|
|
return cgroup, nil
|
|
}
|
|
|
|
// parseCgroups reads each line of the /proc/[pid]/cgroup file.
|
|
func parseCgroups(data []byte) ([]Cgroup, error) {
|
|
var cgroups []Cgroup
|
|
scanner := bufio.NewScanner(bytes.NewReader(data))
|
|
for scanner.Scan() {
|
|
mountString := scanner.Text()
|
|
parsedMounts, err := parseCgroupString(mountString)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
cgroups = append(cgroups, *parsedMounts)
|
|
}
|
|
|
|
err := scanner.Err()
|
|
return cgroups, err
|
|
}
|
|
|
|
// Cgroups reads from /proc/<pid>/cgroups and returns a []*Cgroup struct locating this PID in each process
|
|
// control hierarchy running on this system. On every system (v1 and v2), all hierarchies contain all processes,
|
|
// so the len of the returned struct is equal to the number of active hierarchies on this system.
|
|
func (p Proc) Cgroups() ([]Cgroup, error) {
|
|
data, err := util.ReadFileNoStat(p.path("cgroup"))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return parseCgroups(data)
|
|
}
|