diff options
Diffstat (limited to 'vendor/github.com/prometheus/procfs/proc_cgroup.go')
-rw-r--r-- | vendor/github.com/prometheus/procfs/proc_cgroup.go | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/vendor/github.com/prometheus/procfs/proc_cgroup.go b/vendor/github.com/prometheus/procfs/proc_cgroup.go new file mode 100644 index 0000000..4abd464 --- /dev/null +++ b/vendor/github.com/prometheus/procfs/proc_cgroup.go | |||
@@ -0,0 +1,98 @@ | |||
1 | // Copyright 2020 The Prometheus Authors | ||
2 | // Licensed under the Apache License, Version 2.0 (the "License"); | ||
3 | // you may not use this file except in compliance with the License. | ||
4 | // You may obtain a copy of the License at | ||
5 | // | ||
6 | // http://www.apache.org/licenses/LICENSE-2.0 | ||
7 | // | ||
8 | // Unless required by applicable law or agreed to in writing, software | ||
9 | // distributed under the License is distributed on an "AS IS" BASIS, | ||
10 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
11 | // See the License for the specific language governing permissions and | ||
12 | // limitations under the License. | ||
13 | |||
14 | package procfs | ||
15 | |||
16 | import ( | ||
17 | "bufio" | ||
18 | "bytes" | ||
19 | "fmt" | ||
20 | "strconv" | ||
21 | "strings" | ||
22 | |||
23 | "github.com/prometheus/procfs/internal/util" | ||
24 | ) | ||
25 | |||
26 | // Cgroup models one line from /proc/[pid]/cgroup. Each Cgroup struct describes the the placement of a PID inside a | ||
27 | // specific control hierarchy. The kernel has two cgroup APIs, v1 and v2. v1 has one hierarchy per available resource | ||
28 | // controller, while v2 has one unified hierarchy shared by all controllers. Regardless of v1 or v2, all hierarchies | ||
29 | // contain all running processes, so the question answerable with a Cgroup struct is 'where is this process in | ||
30 | // this hierarchy' (where==what path on the specific cgroupfs). By prefixing this path with the mount point of | ||
31 | // *this specific* hierarchy, you can locate the relevant pseudo-files needed to read/set the data for this PID | ||
32 | // in this hierarchy | ||
33 | // | ||
34 | // Also see http://man7.org/linux/man-pages/man7/cgroups.7.html | ||
35 | type Cgroup struct { | ||
36 | // HierarchyID that can be matched to a named hierarchy using /proc/cgroups. Cgroups V2 only has one | ||
37 | // hierarchy, so HierarchyID is always 0. For cgroups v1 this is a unique ID number | ||
38 | HierarchyID int | ||
39 | // Controllers using this hierarchy of processes. Controllers are also known as subsystems. For | ||
40 | // Cgroups V2 this may be empty, as all active controllers use the same hierarchy | ||
41 | Controllers []string | ||
42 | // Path of this control group, relative to the mount point of the cgroupfs representing this specific | ||
43 | // hierarchy | ||
44 | Path string | ||
45 | } | ||
46 | |||
47 | // parseCgroupString parses each line of the /proc/[pid]/cgroup file | ||
48 | // Line format is hierarchyID:[controller1,controller2]:path | ||
49 | func parseCgroupString(cgroupStr string) (*Cgroup, error) { | ||
50 | var err error | ||
51 | |||
52 | fields := strings.Split(cgroupStr, ":") | ||
53 | if len(fields) < 3 { | ||
54 | return nil, fmt.Errorf("at least 3 fields required, found %d fields in cgroup string: %s", len(fields), cgroupStr) | ||
55 | } | ||
56 | |||
57 | cgroup := &Cgroup{ | ||
58 | Path: fields[2], | ||
59 | Controllers: nil, | ||
60 | } | ||
61 | cgroup.HierarchyID, err = strconv.Atoi(fields[0]) | ||
62 | if err != nil { | ||
63 | return nil, fmt.Errorf("failed to parse hierarchy ID") | ||
64 | } | ||
65 | if fields[1] != "" { | ||
66 | ssNames := strings.Split(fields[1], ",") | ||
67 | cgroup.Controllers = append(cgroup.Controllers, ssNames...) | ||
68 | } | ||
69 | return cgroup, nil | ||
70 | } | ||
71 | |||
72 | // parseCgroups reads each line of the /proc/[pid]/cgroup file | ||
73 | func parseCgroups(data []byte) ([]Cgroup, error) { | ||
74 | var cgroups []Cgroup | ||
75 | scanner := bufio.NewScanner(bytes.NewReader(data)) | ||
76 | for scanner.Scan() { | ||
77 | mountString := scanner.Text() | ||
78 | parsedMounts, err := parseCgroupString(mountString) | ||
79 | if err != nil { | ||
80 | return nil, err | ||
81 | } | ||
82 | cgroups = append(cgroups, *parsedMounts) | ||
83 | } | ||
84 | |||
85 | err := scanner.Err() | ||
86 | return cgroups, err | ||
87 | } | ||
88 | |||
89 | // Cgroups reads from /proc/<pid>/cgroups and returns a []*Cgroup struct locating this PID in each process | ||
90 | // control hierarchy running on this system. On every system (v1 and v2), all hierarchies contain all processes, | ||
91 | // so the len of the returned struct is equal to the number of active hierarchies on this system | ||
92 | func (p Proc) Cgroups() ([]Cgroup, error) { | ||
93 | data, err := util.ReadFileNoStat(fmt.Sprintf("/proc/%d/cgroup", p.PID)) | ||
94 | if err != nil { | ||
95 | return nil, err | ||
96 | } | ||
97 | return parseCgroups(data) | ||
98 | } | ||