Move sys to pkg/sys

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/sys/oom_linux_test.go

@@ -0,0 +1,129 @@
+/*
+   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 (
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"testing"
+	"time"
+
+	"github.com/containerd/containerd/v2/pkg/userns"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSetPositiveOomScoreAdjustment(t *testing.T) {
+	// Setting a *positive* OOM score adjust does not require privileged
+	_, adjustment, err := adjustOom(123)
+	assert.NoError(t, err)
+	assert.EqualValues(t, adjustment, 123)
+}
+
+func TestSetNegativeOomScoreAdjustmentWhenPrivileged(t *testing.T) {
+	if !runningPrivileged() || userns.RunningInUserNS() {
+		t.Skip("requires root and not running in user namespace")
+		return
+	}
+
+	_, adjustment, err := adjustOom(-123)
+	assert.NoError(t, err)
+	assert.EqualValues(t, adjustment, -123)
+}
+
+func TestSetNegativeOomScoreAdjustmentWhenUnprivilegedHasNoEffect(t *testing.T) {
+	if runningPrivileged() && !userns.RunningInUserNS() {
+		t.Skip("needs to be run as non-root or in user namespace")
+		return
+	}
+
+	initial, adjustment, err := adjustOom(-123)
+	assert.NoError(t, err)
+	assert.EqualValues(t, adjustment, initial)
+}
+
+func TestSetOOMScoreBoundaries(t *testing.T) {
+	err := SetOOMScore(0, OOMScoreAdjMax+1)
+	require.NotNil(t, err)
+	assert.Contains(t, err.Error(), fmt.Sprintf("value out of range (%d): OOM score must be between", OOMScoreAdjMax+1))
+
+	err = SetOOMScore(0, OOMScoreAdjMin-1)
+	require.NotNil(t, err)
+	assert.Contains(t, err.Error(), fmt.Sprintf("value out of range (%d): OOM score must be between", OOMScoreAdjMin-1))
+
+	_, adjustment, err := adjustOom(OOMScoreAdjMax)
+	assert.NoError(t, err)
+	assert.EqualValues(t, adjustment, OOMScoreAdjMax)
+
+	score, err := GetOOMScoreAdj(os.Getpid())
+	assert.NoError(t, err)
+	if score == OOMScoreAdjMin {
+		// We won't be able to set the score lower than the parent process. This
+		// could also be tested if the parent process does not have a oom-score-adj
+		// set, but GetOOMScoreAdj does not distinguish between "not set" and
+		// "score is set, but zero".
+		_, adjustment, err = adjustOom(OOMScoreAdjMin)
+		assert.NoError(t, err)
+		assert.EqualValues(t, adjustment, OOMScoreAdjMin)
+	}
+}
+
+func adjustOom(adjustment int) (int, int, error) {
+	cmd := exec.Command("sleep", "100")
+	if err := cmd.Start(); err != nil {
+		return 0, 0, err
+	}
+
+	defer cmd.Process.Kill()
+
+	pid, err := waitForPid(cmd.Process)
+	if err != nil {
+		return 0, 0, err
+	}
+	initial, err := GetOOMScoreAdj(pid)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	if err := SetOOMScore(pid, adjustment); err != nil {
+		return 0, 0, err
+	}
+
+	adj, err := GetOOMScoreAdj(pid)
+	return initial, adj, err
+}
+
+func waitForPid(process *os.Process) (int, error) {
+	c := make(chan int, 1)
+	go func() {
+		for {
+			pid := process.Pid
+			if pid != 0 {
+				c <- pid
+			}
+		}
+	}()
+
+	select {
+	case pid := <-c:
+		return pid, nil
+	case <-time.After(10 * time.Second):
+		return 0, errors.New("process did not start in 10 seconds")
+	}
+}