net: fix dial race on plan9 and windows

Fixes #5349.

R=golang-dev, lucio.dere, dsymonds, bradfitz, iant, adg, dave, r
CC=golang-dev
https://golang.org/cl/9159043

diff --git a/src/pkg/net/dial_gen.go b/src/pkg/net/dial_gen.go
index 0a3277de469e2d6706542c8430dff1124d84a768..19f8681682152194c9ca3efdf1c7ac3641202c83 100644 (file)
--- a/src/pkg/net/dial_gen.go
+++ b/src/pkg/net/dial_gen.go
@@ -10,14 +10,23 @@ import (
        "time"
 )
 
+var testingIssue5349 bool // used during tests
+
 // resolveAndDialChannel is the simple pure-Go implementation of
 // resolveAndDial, still used on operating systems where the deadline
 // hasn't been pushed down into the pollserver. (Plan 9 and some old
 // versions of Windows)
 func resolveAndDialChannel(net, addr string, localAddr Addr, deadline time.Time) (Conn, error) {
-       timeout := deadline.Sub(time.Now())
-       if timeout < 0 {
-               timeout = 0
+       var timeout time.Duration
+       if !deadline.IsZero() {
+               timeout = deadline.Sub(time.Now())
+       }
+       if timeout <= 0 {
+               ra, err := resolveAddr("dial", net, addr, noDeadline)
+               if err != nil {
+                       return nil, err
+               }
+               return dial(net, addr, localAddr, ra, noDeadline)
        }
        t := time.NewTimer(timeout)
        defer t.Stop()
@@ -28,6 +37,9 @@ func resolveAndDialChannel(net, addr string, localAddr Addr, deadline time.Time)
        ch := make(chan pair, 1)
        resolvedAddr := make(chan Addr, 1)
        go func() {
+               if testingIssue5349 {
+                       time.Sleep(time.Millisecond)
+               }
                ra, err := resolveAddr("dial", net, addr, noDeadline)
                if err != nil {
                        ch <- pair{nil, err}

diff --git a/src/pkg/net/dial_gen_test.go b/src/pkg/net/dial_gen_test.go
new file mode 100644 (file)
index 0000000..c857acd
--- /dev/null
+++ b/src/pkg/net/dial_gen_test.go
@@ -0,0 +1,11 @@
+// Copyright 2013 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 windows plan9
+
+package net
+
+func init() {
+       testingIssue5349 = true
+}