[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, 14 deletions

diff --git a/src/pkg/net/sock_posix.go b/src/pkg/net/sock_posix.go
index a6ef874c9f..c80c7d6a2f 100644
--- a/src/pkg/net/sock_posix.go
+++ b/src/pkg/net/sock_posix.go
@@ -107,24 +107,18 @@ func (fd *netFD) dial(laddr, raddr sockaddr, deadline time.Time, toAddr func(sys
 			}
 		}
 	}
-	if err := fd.init(); err != nil {
-		return err
-	}
 	var rsa syscall.Sockaddr
 	if raddr != nil {
 		if rsa, err = raddr.sockaddr(fd.family); err != nil {
 			return err
-		} else if rsa != nil {
-			if !deadline.IsZero() {
-				fd.setWriteDeadline(deadline)
-			}
-			if err := fd.connect(lsa, rsa); err != nil {
-				return err
-			}
-			fd.isConnected = true
-			if !deadline.IsZero() {
-				fd.setWriteDeadline(noDeadline)
-			}
+		}
+		if err := fd.connect(lsa, rsa, deadline); err != nil {
+			return err
+		}
+		fd.isConnected = true
+	} else {
+		if err := fd.init(); err != nil {
+			return err
 		}
 	}
 	lsa, _ = syscall.Getsockname(fd.sysfd)