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// Copyright 2016 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.
//go:build unix
package net
import (
"context"
"errors"
"syscall"
"testing"
"time"
)
func init() {
isEADDRINUSE = func(err error) bool {
return errors.Is(err, syscall.EADDRINUSE)
}
}
// Issue 16523
func TestDialContextCancelRace(t *testing.T) {
oldConnectFunc := connectFunc
oldGetsockoptIntFunc := getsockoptIntFunc
oldTestHookCanceledDial := testHookCanceledDial
defer func() {
connectFunc = oldConnectFunc
getsockoptIntFunc = oldGetsockoptIntFunc
testHookCanceledDial = oldTestHookCanceledDial
}()
ln := newLocalListener(t, "tcp")
listenerDone := make(chan struct{})
go func() {
defer close(listenerDone)
c, err := ln.Accept()
if err == nil {
c.Close()
}
}()
defer func() { <-listenerDone }()
defer ln.Close()
sawCancel := make(chan bool, 1)
testHookCanceledDial = func() {
sawCancel <- true
}
ctx, cancelCtx := context.WithCancel(context.Background())
connectFunc = func(fd int, addr syscall.Sockaddr) error {
err := oldConnectFunc(fd, addr)
t.Logf("connect(%d, addr) = %v", fd, err)
if err == nil {
// On some operating systems, localhost
// connects _sometimes_ succeed immediately.
// Prevent that, so we exercise the code path
// we're interested in testing. This seems
// harmless. It makes FreeBSD 10.10 work when
// run with many iterations. It failed about
// half the time previously.
return syscall.EINPROGRESS
}
return err
}
getsockoptIntFunc = func(fd, level, opt int) (val int, err error) {
val, err = oldGetsockoptIntFunc(fd, level, opt)
t.Logf("getsockoptIntFunc(%d, %d, %d) = (%v, %v)", fd, level, opt, val, err)
if level == syscall.SOL_SOCKET && opt == syscall.SO_ERROR && err == nil && val == 0 {
t.Logf("canceling context")
// Cancel the context at just the moment which
// caused the race in issue 16523.
cancelCtx()
// And wait for the "interrupter" goroutine to
// cancel the dial by messing with its write
// timeout before returning.
select {
case <-sawCancel:
t.Logf("saw cancel")
case <-time.After(5 * time.Second):
t.Errorf("didn't see cancel after 5 seconds")
}
}
return
}
var d Dialer
c, err := d.DialContext(ctx, "tcp", ln.Addr().String())
if err == nil {
c.Close()
t.Fatal("unexpected successful dial; want context canceled error")
}
select {
case <-ctx.Done():
case <-time.After(5 * time.Second):
t.Fatal("expected context to be canceled")
}
oe, ok := err.(*OpError)
if !ok || oe.Op != "dial" {
t.Fatalf("Dial error = %#v; want dial *OpError", err)
}
if oe.Err != errCanceled {
t.Errorf("DialContext = (%v, %v); want OpError with error %v", c, err, errCanceled)
}
}
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