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// Copyright 2020 The gVisor 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 root
import (
"bytes"
"fmt"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"strconv"
"strings"
"testing"
"time"
"github.com/cenkalti/backoff"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/test/testutil"
"gvisor.dev/gvisor/runsc/specutils"
)
// TestDoKill checks that when "runsc do..." is killed, the sandbox process is
// also terminated. This ensures that parent death signal is propagate to the
// sandbox process correctly.
func TestDoKill(t *testing.T) {
// Make the sandbox process be reparented here when it's killed, so we can
// wait for it.
if err := unix.Prctl(unix.PR_SET_CHILD_SUBREAPER, 1, 0, 0, 0); err != nil {
t.Fatalf("prctl(PR_SET_CHILD_SUBREAPER): %v", err)
}
cmd := exec.Command(specutils.ExePath, "do", "sleep", "10000")
buf := &bytes.Buffer{}
cmd.Stdout = buf
cmd.Stderr = buf
cmd.Start()
var pid int
findSandbox := func() error {
var err error
pid, err = sandboxPid(cmd.Process.Pid)
if err != nil {
return &backoff.PermanentError{Err: err}
}
if pid == 0 {
return fmt.Errorf("sandbox process not found")
}
return nil
}
if err := testutil.Poll(findSandbox, 10*time.Second); err != nil {
t.Fatalf("failed to find sandbox: %v", err)
}
t.Logf("Found sandbox, pid: %d", pid)
if err := cmd.Process.Kill(); err != nil {
t.Fatalf("failed to kill run process: %v", err)
}
cmd.Wait()
t.Logf("Parent process killed (%d). Output: %s", cmd.Process.Pid, buf.String())
ch := make(chan struct{})
go func() {
defer func() { ch <- struct{}{} }()
t.Logf("Waiting for sandbox process (%d) termination", pid)
if _, err := unix.Wait4(pid, nil, 0, nil); err != nil {
t.Errorf("error waiting for sandbox process (%d): %v", pid, err)
}
}()
select {
case <-ch:
// Done
case <-time.After(5 * time.Second):
t.Fatalf("timeout waiting for sandbox process (%d) to exit", pid)
}
}
// sandboxPid looks for the sandbox process inside the process tree starting
// from "pid". It returns 0 and no error if no sandbox process is found. It
// returns error if anything failed.
func sandboxPid(pid int) (int, error) {
cmd := exec.Command("pgrep", "-P", strconv.Itoa(pid))
buf := &bytes.Buffer{}
cmd.Stdout = buf
if err := cmd.Start(); err != nil {
return 0, err
}
ps, err := cmd.Process.Wait()
if err != nil {
return 0, err
}
if ps.ExitCode() == 1 {
// pgrep returns 1 when no process is found.
return 0, nil
}
var children []int
for _, line := range strings.Split(buf.String(), "\n") {
if len(line) == 0 {
continue
}
child, err := strconv.Atoi(line)
if err != nil {
return 0, err
}
cmdline, err := ioutil.ReadFile(filepath.Join("/proc", line, "cmdline"))
if err != nil {
if os.IsNotExist(err) {
// Raced with process exit.
continue
}
return 0, err
}
args := strings.SplitN(string(cmdline), "\x00", 2)
if len(args) == 0 {
return 0, fmt.Errorf("malformed cmdline file: %q", cmdline)
}
// The sandbox process has the first argument set to "runsc-sandbox".
if args[0] == "runsc-sandbox" {
return child, nil
}
children = append(children, child)
}
// Sandbox process wasn't found, try another level down.
for _, pid := range children {
sand, err := sandboxPid(pid)
if err != nil {
return 0, err
}
if sand != 0 {
return sand, nil
}
// Not found, continue the search.
}
return 0, nil
}
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