containerd/sys/oom_linux.go
Sebastiaan van Stijn 44240116aa
sys: add boundary checks to SetOOMScore()
Produce a more user-friendly error in the odd case we would try to set a
score out of range

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2021-04-07 19:16:55 +02:00

74 lines
2.2 KiB
Go

/*
Copyright The containerd 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 sys
import (
"fmt"
"io/ioutil"
"os"
"strconv"
"strings"
"github.com/containerd/containerd/pkg/userns"
"golang.org/x/sys/unix"
)
const (
// OOMScoreMaxKillable is the maximum score keeping the process killable by the oom killer
OOMScoreMaxKillable = -999
// OOMScoreAdjMin is from OOM_SCORE_ADJ_MIN https://github.com/torvalds/linux/blob/v5.10/include/uapi/linux/oom.h#L9
OOMScoreAdjMin = -1000
// OOMScoreAdjMax is from OOM_SCORE_ADJ_MAX https://github.com/torvalds/linux/blob/v5.10/include/uapi/linux/oom.h#L10
OOMScoreAdjMax = 1000
)
// SetOOMScore sets the oom score for the provided pid
func SetOOMScore(pid, score int) error {
if score > OOMScoreAdjMax || score < OOMScoreAdjMin {
return fmt.Errorf("value out of range (%d): OOM score must be between %d and %d", score, OOMScoreAdjMin, OOMScoreAdjMax)
}
path := fmt.Sprintf("/proc/%d/oom_score_adj", pid)
f, err := os.OpenFile(path, os.O_WRONLY, 0)
if err != nil {
return err
}
defer f.Close()
if _, err = f.WriteString(strconv.Itoa(score)); err != nil {
if os.IsPermission(err) && (!runningPrivileged() || userns.RunningInUserNS()) {
return nil
}
return err
}
return nil
}
// GetOOMScoreAdj gets the oom score for a process
func GetOOMScoreAdj(pid int) (int, error) {
path := fmt.Sprintf("/proc/%d/oom_score_adj", pid)
data, err := ioutil.ReadFile(path)
if err != nil {
return 0, err
}
return strconv.Atoi(strings.TrimSpace(string(data)))
}
// runningPrivileged returns true if the effective user ID of the
// calling process is 0
func runningPrivileged() bool {
return unix.Geteuid() == 0
}