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libcontainer/cgroups: rm FindCgroupMountpointDir 

This function is cgroupv1-specific, is only used once, and its name
is very close to the name of another function, FindCgroupMountpoint.

Inline it into the (only) caller.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This commit is contained in:
Kir Kolyshkin 2020-05-15 14:13:25 -07:00
parent d244b4058e
commit 7db2d3e146
2 changed files with 36 additions and 38 deletions
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37
libcontainer/cgroups/fs/apply_raw.go
View File

@ -3,9 +3,11 @@
package fs
import (
"bufio"
"fmt"
"os"
"path/filepath"
"strings"
"sync"
"github.com/opencontainers/runc/libcontainer/cgroups"
@ -88,10 +90,43 @@ func getCgroupRoot() (string, error) {
return cgroupRoot, nil
}
root, err := cgroups.FindCgroupMountpointDir()
f, err := os.Open("/proc/self/mountinfo")
if err != nil {
return "", err
}
defer f.Close()
var root string
scanner := bufio.NewScanner(f)
for scanner.Scan() {
text := scanner.Text()
fields := strings.Split(text, " ")
// Safe as mountinfo encodes mountpoints with spaces as \040.
index := strings.Index(text, " - ")
postSeparatorFields := strings.Fields(text[index+3:])
numPostFields := len(postSeparatorFields)
// This is an error as we can't detect if the mount is for "cgroup"
if numPostFields == 0 {
return "", fmt.Errorf("mountinfo: found no fields post '-' in %q", text)
}
if postSeparatorFields[0] == "cgroup" {
// Check that the mount is properly formatted.
if numPostFields < 3 {
return "", fmt.Errorf("Error found less than 3 fields post '-' in %q", text)
}
root = filepath.Dir(fields[4])
break
}
}
if err := scanner.Err(); err != nil {
return "", err
}
if root == "" {
return "", errors.New("no cgroup mount found in mountinfo")
}
if _, err := os.Stat(root); err != nil {
return "", err

37
libcontainer/cgroups/utils.go
View File

@ -117,43 +117,6 @@ func isSubsystemAvailable(subsystem string) bool {
return avail
}
func FindCgroupMountpointDir() (string, error) {
f, err := os.Open("/proc/self/mountinfo")
if err != nil {
return "", err
}
defer f.Close()
scanner := bufio.NewScanner(f)
for scanner.Scan() {
text := scanner.Text()
fields := strings.Split(text, " ")
// Safe as mountinfo encodes mountpoints with spaces as \040.
index := strings.Index(text, " - ")
postSeparatorFields := strings.Fields(text[index+3:])
numPostFields := len(postSeparatorFields)
// This is an error as we can't detect if the mount is for "cgroup"
if numPostFields == 0 {
return "", fmt.Errorf("Found no fields post '-' in %q", text)
}
if postSeparatorFields[0] == "cgroup" || postSeparatorFields[0] == "cgroup2" {
// Check that the mount is properly formatted.
if numPostFields < 3 {
return "", fmt.Errorf("Error found less than 3 fields post '-' in %q", text)
}
return filepath.Dir(fields[4]), nil
}
}
if err := scanner.Err(); err != nil {
return "", err
}
return "", NewNotFoundError("cgroup")
}
type Mount struct {
Mountpoint string
Root string