Commit 99957b69 authored by Ian Lance Taylor's avatar Ian Lance Taylor

runtime: use pipe rather than note in TestSignalM

At least on Darwin notewakeup is not async-signal-safe.

Fixes #35276

Change-Id: I1d7523715e8e77dbd7f21d9b1ed131e52d46cc41
Reviewed-on: https://go-review.googlesource.com/c/go/+/206078Reviewed-by: default avatarAustin Clements <austin@google.com>
parent d22b5735
......@@ -18,6 +18,7 @@ import (
"sync"
"syscall"
"testing"
"time"
"unsafe"
)
......@@ -308,20 +309,45 @@ func TestSignalDuringExec(t *testing.T) {
}
func TestSignalM(t *testing.T) {
r, w, errno := runtime.Pipe()
if errno != 0 {
t.Fatal(syscall.Errno(errno))
}
defer func() {
runtime.Close(r)
runtime.Close(w)
}()
runtime.Closeonexec(r)
runtime.Closeonexec(w)
var want, got int64
var wg sync.WaitGroup
ready := make(chan *runtime.M)
wg.Add(1)
go func() {
runtime.LockOSThread()
want, got = runtime.WaitForSigusr1(func(mp *runtime.M) {
var errno int32
want, got = runtime.WaitForSigusr1(r, w, func(mp *runtime.M) {
ready <- mp
}, 1e9)
})
if errno != 0 {
t.Error(syscall.Errno(errno))
}
runtime.UnlockOSThread()
wg.Done()
}()
waitingM := <-ready
runtime.SendSigusr1(waitingM)
timer := time.AfterFunc(time.Second, func() {
// Write 1 to tell WaitForSigusr1 that we timed out.
bw := byte(1)
if n := runtime.Write(uintptr(w), unsafe.Pointer(&bw), 1); n != 1 {
t.Errorf("pipe write failed: %d", n)
}
})
defer timer.Stop()
wg.Wait()
if got == -1 {
t.Fatal("signalM signal not received")
......
......@@ -6,6 +6,8 @@
package runtime
import "unsafe"
var NonblockingPipe = nonblockingPipe
var Pipe = pipe
var SetNonblock = setNonblock
......@@ -26,33 +28,45 @@ func Sigisblocked(i int) bool {
type M = m
var waitForSigusr1 struct {
park note
mID int64
rdpipe int32
wrpipe int32
mID int64
}
// WaitForSigusr1 blocks until a SIGUSR1 is received. It calls ready
// when it is set up to receive SIGUSR1. The ready function should
// cause a SIGUSR1 to be sent.
// cause a SIGUSR1 to be sent. The r and w arguments are a pipe that
// the signal handler can use to report when the signal is received.
//
// Once SIGUSR1 is received, it returns the ID of the current M and
// the ID of the M the SIGUSR1 was received on. If no SIGUSR1 is
// received for timeoutNS nanoseconds, it returns -1.
func WaitForSigusr1(ready func(mp *M), timeoutNS int64) (int64, int64) {
// the ID of the M the SIGUSR1 was received on. If the caller writes
// a non-zero byte to w, WaitForSigusr1 returns immediately with -1, -1.
func WaitForSigusr1(r, w int32, ready func(mp *M)) (int64, int64) {
lockOSThread()
// Make sure we can receive SIGUSR1.
unblocksig(_SIGUSR1)
waitForSigusr1.rdpipe = r
waitForSigusr1.wrpipe = w
mp := getg().m
testSigusr1 = waitForSigusr1Callback
ready(mp)
ok := notetsleepg(&waitForSigusr1.park, timeoutNS)
noteclear(&waitForSigusr1.park)
// Wait for the signal. We use a pipe rather than a note
// because write is always async-signal-safe.
entersyscallblock()
var b byte
read(waitForSigusr1.rdpipe, noescape(unsafe.Pointer(&b)), 1)
exitsyscall()
gotM := waitForSigusr1.mID
testSigusr1 = nil
unlockOSThread()
if !ok {
if b != 0 {
// timeout signal from caller
return -1, -1
}
return mp.id, gotM
......@@ -69,7 +83,8 @@ func waitForSigusr1Callback(gp *g) bool {
} else {
waitForSigusr1.mID = gp.m.id
}
notewakeup(&waitForSigusr1.park)
b := byte(0)
write(uintptr(waitForSigusr1.wrpipe), noescape(unsafe.Pointer(&b)), 1)
return true
}
......
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