[release-branch.go1.3] net: prevent spurious on-connect events via epoll on linuxgo1.3.1

««« CL 120820043 / 06a4b59c1393
net: prevent spurious on-connect events via epoll on linux

On Linux, adding a socket descriptor to epoll instance before getting
the EINPROGRESS return value from connect system call could be a root
cause of spurious on-connect events.

See golang.org/issue/8276, golang.org/issue/8426 for further information.

All credit to Jason Eggleston <jason@eggnet.com>

Fixes #8276.
Fixes #8426.

LGTM=dvyukov
R=dvyukov, golang-codereviews, adg, dave, iant, alex.brainman
CC=golang-codereviews
https://golang.org/cl/120820043
»»»

TBR=r, rsc
CC=golang-codereviews
https://golang.org/cl/128110045

1 files changed, 8 insertions, 1 deletions

diff --git a/src/pkg/net/fd_windows.go b/src/pkg/net/fd_windows.go
index a1f6bc5f81..d1129dccc4 100644
--- a/src/pkg/net/fd_windows.go
+++ b/src/pkg/net/fd_windows.go
@@ -313,10 +313,17 @@ func (fd *netFD) setAddr(laddr, raddr Addr) {
 	runtime.SetFinalizer(fd, (*netFD).Close)
 }
 
-func (fd *netFD) connect(la, ra syscall.Sockaddr) error {
+func (fd *netFD) connect(la, ra syscall.Sockaddr, deadline time.Time) error {
 	// Do not need to call fd.writeLock here,
 	// because fd is not yet accessible to user,
 	// so no concurrent operations are possible.
+	if err := fd.init(); err != nil {
+		return err
+	}
+	if !deadline.IsZero() {
+		fd.setWriteDeadline(deadline)
+		defer fd.setWriteDeadline(noDeadline)
+	}
 	if !canUseConnectEx(fd.net) {
 		return syscall.Connect(fd.sysfd, ra)
 	}