-
Notifications
You must be signed in to change notification settings - Fork 0
/
utils.go
205 lines (174 loc) · 3.92 KB
/
utils.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
package cgroups
import (
"bufio"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"github.com/docker/docker/pkg/mount"
)
// https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt
func FindCgroupMountpoint(subsystem string) (string, error) {
mounts, err := mount.GetMounts()
if err != nil {
return "", err
}
for _, mount := range mounts {
if mount.Fstype == "cgroup" {
for _, opt := range strings.Split(mount.VfsOpts, ",") {
if opt == subsystem {
return mount.Mountpoint, nil
}
}
}
}
return "", NewNotFoundError(subsystem)
}
type Mount struct {
Mountpoint string
Subsystems []string
}
func (m Mount) GetThisCgroupDir() (string, error) {
if len(m.Subsystems) == 0 {
return "", fmt.Errorf("no subsystem for mount")
}
return GetThisCgroupDir(m.Subsystems[0])
}
func GetCgroupMounts() ([]Mount, error) {
mounts, err := mount.GetMounts()
if err != nil {
return nil, err
}
all, err := GetAllSubsystems()
if err != nil {
return nil, err
}
allMap := make(map[string]bool)
for _, s := range all {
allMap[s] = true
}
res := []Mount{}
for _, mount := range mounts {
if mount.Fstype == "cgroup" {
m := Mount{Mountpoint: mount.Mountpoint}
for _, opt := range strings.Split(mount.VfsOpts, ",") {
if strings.HasPrefix(opt, "name=") {
m.Subsystems = append(m.Subsystems, opt)
}
if allMap[opt] {
m.Subsystems = append(m.Subsystems, opt)
}
}
res = append(res, m)
}
}
return res, nil
}
// Returns all the cgroup subsystems supported by the kernel
func GetAllSubsystems() ([]string, error) {
f, err := os.Open("/proc/cgroups")
if err != nil {
return nil, err
}
defer f.Close()
subsystems := []string{}
s := bufio.NewScanner(f)
for s.Scan() {
if err := s.Err(); err != nil {
return nil, err
}
text := s.Text()
if text[0] != '#' {
parts := strings.Fields(text)
if len(parts) >= 4 && parts[3] != "0" {
subsystems = append(subsystems, parts[0])
}
}
}
return subsystems, nil
}
// Returns the relative path to the cgroup docker is running in.
func GetThisCgroupDir(subsystem string) (string, error) {
f, err := os.Open("/proc/self/cgroup")
if err != nil {
return "", err
}
defer f.Close()
return ParseCgroupFile(subsystem, f)
}
func GetInitCgroupDir(subsystem string) (string, error) {
f, err := os.Open("/proc/1/cgroup")
if err != nil {
return "", err
}
defer f.Close()
return ParseCgroupFile(subsystem, f)
}
func ReadProcsFile(dir string) ([]int, error) {
f, err := os.Open(filepath.Join(dir, "cgroup.procs"))
if err != nil {
return nil, err
}
defer f.Close()
var (
s = bufio.NewScanner(f)
out = []int{}
)
for s.Scan() {
if t := s.Text(); t != "" {
pid, err := strconv.Atoi(t)
if err != nil {
return nil, err
}
out = append(out, pid)
}
}
return out, nil
}
func ParseCgroupFile(subsystem string, r io.Reader) (string, error) {
s := bufio.NewScanner(r)
for s.Scan() {
if err := s.Err(); err != nil {
return "", err
}
text := s.Text()
parts := strings.Split(text, ":")
for _, subs := range strings.Split(parts[1], ",") {
if subs == subsystem {
return parts[2], nil
}
}
}
return "", NewNotFoundError(subsystem)
}
func pathExists(path string) bool {
if _, err := os.Stat(path); err != nil {
return false
}
return true
}
func EnterPid(cgroupPaths map[string]string, pid int) error {
for _, path := range cgroupPaths {
if pathExists(path) {
if err := ioutil.WriteFile(filepath.Join(path, "cgroup.procs"),
[]byte(strconv.Itoa(pid)), 0700); err != nil {
return err
}
}
}
return nil
}
// RemovePaths iterates over the provided paths removing them.
// If an error is encountered the removal proceeds and the first error is
// returned to ensure a partial removal is not possible.
func RemovePaths(paths map[string]string) (err error) {
for _, path := range paths {
if rerr := os.RemoveAll(path); err == nil {
err = rerr
}
}
return err
}