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
diff --git a/src/pkg/net/fd_unix.go b/src/pkg/net/fd_unix.go
index b82ecd1..e22861a 100644
--- a/src/pkg/net/fd_unix.go
+++ b/src/pkg/net/fd_unix.go
@@ -68,16 +68,19 @@
return fd.net + ":" + ls + "->" + rs
}
-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.pd.PrepareWrite(); err != nil {
- return err
- }
switch err := syscall.Connect(fd.sysfd, ra); err {
case syscall.EINPROGRESS, syscall.EALREADY, syscall.EINTR:
case nil, syscall.EISCONN:
+ if !deadline.IsZero() && deadline.Before(time.Now()) {
+ return errTimeout
+ }
+ if err := fd.init(); err != nil {
+ return err
+ }
return nil
case syscall.EINVAL:
// On Solaris we can see EINVAL if the socket has
@@ -92,6 +95,13 @@
default:
return err
}
+ if err := fd.init(); err != nil {
+ return err
+ }
+ if !deadline.IsZero() {
+ fd.setWriteDeadline(deadline)
+ defer fd.setWriteDeadline(noDeadline)
+ }
for {
// Performing multiple connect system calls on a
// non-blocking socket under Unix variants does not
