// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
package signal
import (
"bytes"
"flag"
"fmt"
"internal/testenv"
"io/ioutil"
"os"
"os/exec"
"runtime"
"strconv"
"sync"
"syscall"
"testing"
"time"
)
func waitSig(t *testing.T, c <-chan os.Signal, sig os.Signal) {
select {
case s := <-c:
if s != sig {
t.Fatalf("signal was %v, want %v", s, sig)
}
case <-time.After(1 * time.Second):
t.Fatalf("timeout waiting for %v", sig)
}
}
// Test that basic signal handling works.
func TestSignal(t *testing.T) {
// Ask for SIGHUP
c := make(chan os.Signal, 1)
Notify(c, syscall.SIGHUP)
defer Stop(c)
// Send this process a SIGHUP
t.Logf("sighup...")
syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
waitSig(t, c, syscall.SIGHUP)
// Ask for everything we can get.
c1 := make(chan os.Signal, 1)
Notify(c1)
// Send this process a SIGWINCH
t.Logf("sigwinch...")
syscall.Kill(syscall.Getpid(), syscall.SIGWINCH)
waitSig(t, c1, syscall.SIGWINCH)
// Send two more SIGHUPs, to make sure that
// they get delivered on c1 and that not reading
// from c does not block everything.
t.Logf("sighup...")
syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
waitSig(t, c1, syscall.SIGHUP)
t.Logf("sighup...")
syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
waitSig(t, c1, syscall.SIGHUP)
// The first SIGHUP should be waiting for us on c.
waitSig(t, c, syscall.SIGHUP)
}
func TestStress(t *testing.T) {
dur := 3 * time.Second
if testing.Short() {
dur = 100 * time.Millisecond
}
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
done := make(chan bool)
finished := make(chan bool)
go func() {
sig := make(chan os.Signal, 1)
Notify(sig, syscall.SIGUSR1)
defer Stop(sig)
Loop:
for {
select {
case <-sig:
case <-done:
break Loop
}
}
finished <- true
}()
go func() {
Loop:
for {
select {
case <-done:
break Loop
default:
syscall.Kill(syscall.Getpid(), syscall.SIGUSR1)
runtime.Gosched()
}
}
finished <- true
}()
time.Sleep(dur)
close(done)
<-finished
<-finished
// When run with 'go test -cpu=1,2,4' SIGUSR1 from this test can slip
// into subsequent TestSignal() causing failure.
// Sleep for a while to reduce the possibility of the failure.
time.Sleep(10 * time.Millisecond)
}
func testCancel(t *testing.T, ignore bool) {
// Send SIGWINCH. By default this signal should be ignored.
syscall.Kill(syscall.Getpid(), syscall.SIGWINCH)
time.Sleep(100 * time.Millisecond)
// Ask to be notified on c1 when a SIGWINCH is received.
c1 := make(chan os.Signal, 1)
Notify(c1, syscall.SIGWINCH)
defer Stop(c1)
// Ask to be notified on c2 when a SIGHUP is received.
c2 := make(chan os.Signal, 1)
Notify(c2, syscall.SIGHUP)
defer Stop(c2)
// Send this process a SIGWINCH and wait for notification on c1.
syscall.Kill(syscall.Getpid(), syscall.SIGWINCH)
waitSig(t, c1, syscall.SIGWINCH)
// Send this process a SIGHUP and wait for notification on c2.
syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
waitSig(t, c2, syscall.SIGHUP)
// Ignore, or reset the signal handlers for, SIGWINCH and SIGHUP.
if ignore {
Ignore(syscall.SIGWINCH, syscall.SIGHUP)
} else {
Reset(syscall.SIGWINCH, syscall.SIGHUP)
}
// At this point we do not expect any further signals on c1.
// However, it is just barely possible that the initial SIGWINCH
// at the start of this function was delivered after we called
// Notify on c1. In that case the waitSig for SIGWINCH may have
// picked up that initial SIGWINCH, and the second SIGWINCH may
// then have been delivered on the channel. This sequence of events
// may have caused issue 15661.
// So, read any possible signal from the channel now.
select {
case <-c1:
default:
}
// Send this process a SIGWINCH. It should be ignored.
syscall.Kill(syscall.Getpid(), syscall.SIGWINCH)
// If ignoring, Send this process a SIGHUP. It should be ignored.
if ignore {
syscall.Kill(syscall.Getpid(), syscall.SIGHUP)
}
select {
case s := <-c1:
t.Fatalf("unexpected signal %v", s)
case <-time.After(100 * time.Millisecond):
// nothing to read - good
}
select {
case s := <-c2:
t.Fatalf("unexpected signal %v", s)
case <-time.After(100 * time.Millisecond):
// nothing to read - good
}
// Reset the signal handlers for all signals.
Reset()
}
// Test that Reset cancels registration for listed signals on all channels.
func TestReset(t *testing.T) {
testCancel(t, false)
}
// Test that Ignore cancels registration for listed signals on all channels.
func TestIgnore(t *testing.T) {
testCancel(t, true)
}
// Test that Ignored correctly detects changes to the ignored status of a signal.
func TestIgnored(t *testing.T) {
// Ask to be notified on SIGWINCH.
c := make(chan os.Signal, 1)
Notify(c, syscall.SIGWINCH)
// If we're being notified, then the signal should not be ignored.
if Ignored(syscall.SIGWINCH) {
t.Errorf("expected SIGWINCH to not be ignored.")
}
Stop(c)
Ignore(syscall.SIGWINCH)
// We're no longer paying attention to this signal.
if !Ignored(syscall.SIGWINCH) {
t.Errorf("expected SIGWINCH to be ignored when explicitly ignoring it.")
}
Reset()
}
var checkSighupIgnored = flag.Bool("check_sighup_ignored", false, "if true, TestDetectNohup will fail if SIGHUP is not ignored.")
// Test that Ignored(SIGHUP) correctly detects whether it is being run under nohup.
func TestDetectNohup(t *testing.T) {
if *checkSighupIgnored {
if !Ignored(syscall.SIGHUP) {
t.Fatal("SIGHUP is not ignored.")
} else {
t.Log("SIGHUP is ignored.")
}
} else {
defer Reset()
// Ugly: ask for SIGHUP so that child will not have no-hup set
// even if test is running under nohup environment.
// We have no intention of reading from c.
c := make(chan os.Signal, 1)
Notify(c, syscall.SIGHUP)
if out, err := exec.Command(os.Args[0], "-test.run=TestDetectNohup", "-check_sighup_ignored").CombinedOutput(); err == nil {
t.Errorf("ran test with -check_sighup_ignored and it succeeded: expected failure.\nOutput:\n%s", out)
}
Stop(c)
// Again, this time with nohup, assuming we can find it.
_, err := os.Stat("/usr/bin/nohup")
if err != nil {
t.Skip("cannot find nohup; skipping second half of test")
}
Ignore(syscall.SIGHUP)
os.Remove("nohup.out")
out, err := exec.Command("/usr/bin/nohup", os.Args[0], "-test.run=TestDetectNohup", "-check_sighup_ignored").CombinedOutput()
data, _ := ioutil.ReadFile("nohup.out")
os.Remove("nohup.out")
if err != nil {
t.Errorf("ran test with -check_sighup_ignored under nohup and it failed: expected success.\nError: %v\nOutput:\n%s%s", err, out, data)
}
}
}
var sendUncaughtSighup = flag.Int("send_uncaught_sighup", 0, "send uncaught SIGHUP during TestStop")
// Test that Stop cancels the channel's registrations.
func TestStop(t *testing.T) {
sigs := []syscall.Signal{
syscall.SIGWINCH,
syscall.SIGHUP,
syscall.SIGUSR1,
}
for _, sig := range sigs {
// Send the signal.
// If it's SIGWINCH, we should not see it.
// If it's SIGHUP, maybe we'll die. Let the flag tell us what to do.
if sig == syscall.SIGWINCH || (sig == syscall.SIGHUP && *sendUncaughtSighup == 1) {
syscall.Kill(syscall.Getpid(), sig)
}
time.Sleep(100 * time.Millisecond)
// Ask for signal
c := make(chan os.Signal, 1)
Notify(c, sig)
defer Stop(c)
// Send this process that signal
syscall.Kill(syscall.Getpid(), sig)
waitSig(t, c, sig)
Stop(c)
select {
case s := <-c:
t.Fatalf("unexpected signal %v", s)
case <-time.After(100 * time.Millisecond):
// nothing to read - good
}
// Send the signal.
// If it's SIGWINCH, we should not see it.
// If it's SIGHUP, maybe we'll die. Let the flag tell us what to do.
if sig != syscall.SIGHUP || *sendUncaughtSighup == 2 {
syscall.Kill(syscall.Getpid(), sig)
}
select {
case s := <-c:
t.Fatalf("unexpected signal %v", s)
case <-time.After(100 * time.Millisecond):
// nothing to read - good
}
}
}
// Test that when run under nohup, an uncaught SIGHUP does not kill the program,
// but a
func TestNohup(t *testing.T) {
// Ugly: ask for SIGHUP so that child will not have no-hup set
// even if test is running under nohup environment.
// We have no intention of reading from c.
c := make(chan os.Signal, 1)
Notify(c, syscall.SIGHUP)
// When run without nohup, the test should crash on an uncaught SIGHUP.
// When run under nohup, the test should ignore uncaught SIGHUPs,
// because the runtime is not supposed to be listening for them.
// Either way, TestStop should still be able to catch them when it wants them
// and then when it stops wanting them, the original behavior should resume.
//
// send_uncaught_sighup=1 sends the SIGHUP before starting to listen for SIGHUPs.
// send_uncaught_sighup=2 sends the SIGHUP after no longer listening for SIGHUPs.
//
// Both should fail without nohup and succeed with nohup.
for i := 1; i <= 2; i++ {
out, err := exec.Command(os.Args[0], "-test.run=TestStop", "-send_uncaught_sighup="+strconv.Itoa(i)).CombinedOutput()
if err == nil {
t.Fatalf("ran test with -send_uncaught_sighup=%d and it succeeded: expected failure.\nOutput:\n%s", i, out)
}
}
Stop(c)
// Skip the nohup test below when running in tmux on darwin, since nohup
// doesn't work correctly there. See issue #5135.
if runtime.GOOS == "darwin" && os.Getenv("TMUX") != "" {
t.Skip("Skipping nohup test due to running in tmux on darwin")
}
// Again, this time with nohup, assuming we can find it.
_, err := os.Stat("/usr/bin/nohup")
if err != nil {
t.Skip("cannot find nohup; skipping second half of test")
}
for i := 1; i <= 2; i++ {
os.Remove("nohup.out")
out, err := exec.Command("/usr/bin/nohup", os.Args[0], "-test.run=TestStop", "-send_uncaught_sighup="+strconv.Itoa(i)).CombinedOutput()
data, _ := ioutil.ReadFile("nohup.out")
os.Remove("nohup.out")
if err != nil {
t.Fatalf("ran test with -send_uncaught_sighup=%d under nohup and it failed: expected success.\nError: %v\nOutput:\n%s%s", i, err, out, data)
}
}
}
// Test that SIGCONT works (issue 8953).
func TestSIGCONT(t *testing.T) {
c := make(chan os.Signal, 1)
Notify(c, syscall.SIGCONT)
defer Stop(c)
syscall.Kill(syscall.Getpid(), syscall.SIGCONT)
waitSig(t, c, syscall.SIGCONT)
}
// Test race between stopping and receiving a signal (issue 14571).
func TestAtomicStop(t *testing.T) {
if os.Getenv("GO_TEST_ATOMIC_STOP") != "" {
atomicStopTestProgram()
t.Fatal("atomicStopTestProgram returned")
}
testenv.MustHaveExec(t)
const execs = 10
for i := 0; i < execs; i++ {
cmd := exec.Command(os.Args[0], "-test.run=TestAtomicStop")
cmd.Env = append(os.Environ(), "GO_TEST_ATOMIC_STOP=1")
out, err := cmd.CombinedOutput()
if err == nil {
if len(out) > 0 {
t.Logf("iteration %d: output %s", i, out)
}
} else {
t.Logf("iteration %d: exit status %q: output: %s", i, err, out)
}
lost := bytes.Contains(out, []byte("lost signal"))
if lost {
t.Errorf("iteration %d: lost signal", i)
}
// The program should either die due to SIGINT,
// or exit with success without printing "lost signal".
if err == nil {
if len(out) > 0 && !lost {
t.Errorf("iteration %d: unexpected output", i)
}
} else {
if ee, ok := err.(*exec.ExitError); !ok {
t.Errorf("iteration %d: error (%v) has type %T; expected exec.ExitError", i, err, err)
} else if ws, ok := ee.Sys().(syscall.WaitStatus); !ok {
t.Errorf("iteration %d: error.Sys (%v) has type %T; expected syscall.WaitStatus", i, ee.Sys(), ee.Sys())
} else if !ws.Signaled() || ws.Signal() != syscall.SIGINT {
t.Errorf("iteration %d: got exit status %v; expected SIGINT", i, ee)
}
}
}
}
// atomicStopTestProgram is run in a subprocess by TestAtomicStop.
// It tries to trigger a signal delivery race. This function should
// either catch a signal or die from it.
func atomicStopTestProgram() {
const tries = 10
pid := syscall.Getpid()
printed := false
for i := 0; i < tries; i++ {
cs := make(chan os.Signal, 1)
Notify(cs, syscall.SIGINT)
var wg sync.WaitGroup
wg.Add(1)
go func() {
defer wg.Done()
Stop(cs)
}()
syscall.Kill(pid, syscall.SIGINT)
// At this point we should either die from SIGINT or
// get a notification on cs. If neither happens, we
// dropped the signal. It is given 2 seconds to
// deliver, as needed for gccgo on some loaded test systems.
select {
case <-cs:
case <-time.After(2 * time.Second):
if !printed {
fmt.Print("lost signal on tries:")
printed = true
}
fmt.Printf(" %d", i)
}
wg.Wait()
}
if printed {
fmt.Print("\n")
}
os.Exit(0)
}
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