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net: fix accept/connect deadline handling

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Ensure that accept/connect respect deadline,
even if the operation can be executed w/o blocking.
Note this changes external behavior, but it makes
it consistent with read/write.
Factor out deadline check into pollServer.PrepareRead/Write,
in preparation for edge triggered pollServer.
Ensure that pollServer.WaitRead/Write are not called concurrently
by adding rio/wio locks around connect/accept.

R=golang-dev, mikioh.mikioh, bradfitz, iant
CC=golang-dev
https://golang.org/cl/7436048
This commit is contained in:
Dmitriy Vyukov 2013-03-07 17:03:40 +04:00
parent 48fa4a10fb
commit 0f136f2c05
2 changed files with 101 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
src/pkg/net/fd_unix.go
View File

@ -234,6 +234,20 @@ func (s *pollServer) Run() {
}
}
func (s *pollServer) PrepareRead(fd *netFD) error {
if fd.rdeadline.expired() {
return errTimeout
}
return nil
}
func (s *pollServer) PrepareWrite(fd *netFD) error {
if fd.wdeadline.expired() {
return errTimeout
}
return nil
}
func (s *pollServer) WaitRead(fd *netFD) error {
err := s.AddFD(fd, 'r')
if err == nil {
@ -331,6 +345,11 @@ func (fd *netFD) name() string {
}
func (fd *netFD) connect(ra syscall.Sockaddr) error {
fd.wio.Lock()
defer fd.wio.Unlock()
if err := fd.pollServer.PrepareWrite(fd); err != nil {
return err
}
err := syscall.Connect(fd.sysfd, ra)
if err == syscall.EINPROGRESS {
if err = fd.pollServer.WaitWrite(fd); err != nil {
@ -425,11 +444,10 @@ func (fd *netFD) Read(p []byte) (n int, err error) {
return 0, err
}
defer fd.decref()
if err := fd.pollServer.PrepareRead(fd); err != nil {
return 0, &OpError{"read", fd.net, fd.raddr, err}
}
for {
if fd.rdeadline.expired() {
err = errTimeout
break
}
n, err = syscall.Read(int(fd.sysfd), p)
if err != nil {
n = 0
@ -455,11 +473,10 @@ func (fd *netFD) ReadFrom(p []byte) (n int, sa syscall.Sockaddr, err error) {
return 0, nil, err
}
defer fd.decref()
if err := fd.pollServer.PrepareRead(fd); err != nil {
return 0, nil, &OpError{"read", fd.net, fd.laddr, err}
}
for {
if fd.rdeadline.expired() {
err = errTimeout
break
}
n, sa, err = syscall.Recvfrom(fd.sysfd, p, 0)
if err != nil {
n = 0
@ -485,11 +502,10 @@ func (fd *netFD) ReadMsg(p []byte, oob []byte) (n, oobn, flags int, sa syscall.S
return 0, 0, 0, nil, err
}
defer fd.decref()
if err := fd.pollServer.PrepareRead(fd); err != nil {
return 0, 0, 0, nil, &OpError{"read", fd.net, fd.laddr, err}
}
for {
if fd.rdeadline.expired() {
err = errTimeout
break
}
n, oobn, flags, sa, err = syscall.Recvmsg(fd.sysfd, p, oob, 0)
if err != nil {
// TODO(dfc) should n and oobn be set to 0
@ -522,11 +538,10 @@ func (fd *netFD) Write(p []byte) (nn int, err error) {
return 0, err
}
defer fd.decref()
if err := fd.pollServer.PrepareWrite(fd); err != nil {
return 0, &OpError{"write", fd.net, fd.raddr, err}
}
for {
if fd.wdeadline.expired() {
err = errTimeout
break
}
var n int
n, err = syscall.Write(int(fd.sysfd), p[nn:])
if n > 0 {
@ -562,11 +577,10 @@ func (fd *netFD) WriteTo(p []byte, sa syscall.Sockaddr) (n int, err error) {
return 0, err
}
defer fd.decref()
if err := fd.pollServer.PrepareWrite(fd); err != nil {
return 0, &OpError{"write", fd.net, fd.raddr, err}
}
for {
if fd.wdeadline.expired() {
err = errTimeout
break
}
err = syscall.Sendto(fd.sysfd, p, 0, sa)
if err == syscall.EAGAIN {
if err = fd.pollServer.WaitWrite(fd); err == nil {
@ -590,11 +604,10 @@ func (fd *netFD) WriteMsg(p []byte, oob []byte, sa syscall.Sockaddr) (n int, oob
return 0, 0, err
}
defer fd.decref()
if err := fd.pollServer.PrepareWrite(fd); err != nil {
return 0, 0, &OpError{"write", fd.net, fd.raddr, err}
}
for {
if fd.wdeadline.expired() {
err = errTimeout
break
}
err = syscall.Sendmsg(fd.sysfd, p, oob, sa, 0)
if err == syscall.EAGAIN {
if err = fd.pollServer.WaitWrite(fd); err == nil {
@ -613,6 +626,8 @@ func (fd *netFD) WriteMsg(p []byte, oob []byte, sa syscall.Sockaddr) (n int, oob
}
func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (netfd *netFD, err error) {
fd.rio.Lock()
defer fd.rio.Unlock()
if err := fd.incref(false); err != nil {
return nil, err
}
@ -620,6 +635,9 @@ func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (netfd *netFD, err e
var s int
var rsa syscall.Sockaddr
if err = fd.pollServer.PrepareRead(fd); err != nil {
return nil, &OpError{"accept", fd.net, fd.laddr, err}
}
for {
s, rsa, err = accept(fd.sysfd)
if err != nil {

60
src/pkg/net/timeout_test.go
View File

@ -532,7 +532,7 @@ func TestReadDeadlineDataAvailable(t *testing.T) {
defer ln.Close()
servec := make(chan copyRes)
const msg = "data client shouldn't read, even though it it'll be waiting"
const msg = "data client shouldn't read, even though it'll be waiting"
go func() {
c, err := ln.Accept()
if err != nil {
@ -596,6 +596,64 @@ func TestWriteDeadlineBufferAvailable(t *testing.T) {
}
}
// TestAcceptDeadlineConnectionAvailable tests that accept deadlines work, even
// if there's incoming connections available.
func TestAcceptDeadlineConnectionAvailable(t *testing.T) {
switch runtime.GOOS {
case "plan9":
t.Skipf("skipping test on %q", runtime.GOOS)
}
ln := newLocalListener(t).(*TCPListener)
defer ln.Close()
go func() {
c, err := Dial("tcp", ln.Addr().String())
if err != nil {
t.Fatalf("Dial: %v", err)
}
defer c.Close()
var buf [1]byte
c.Read(buf[:]) // block until the connection or listener is closed
}()
time.Sleep(10 * time.Millisecond)
ln.SetDeadline(time.Now().Add(-5 * time.Second)) // in the past
c, err := ln.Accept()
if err == nil {
defer c.Close()
}
if !isTimeout(err) {
t.Fatalf("Accept: got %v; want timeout", err)
}
}
// TestConnectDeadlineInThePast tests that connect deadlines work, even
// if the connection can be established w/o blocking.
func TestConnectDeadlineInThePast(t *testing.T) {
switch runtime.GOOS {
case "plan9":
t.Skipf("skipping test on %q", runtime.GOOS)
}
ln := newLocalListener(t).(*TCPListener)
defer ln.Close()
go func() {
c, err := ln.Accept()
if err == nil {
defer c.Close()
}
}()
time.Sleep(10 * time.Millisecond)
c, err := DialTimeout("tcp", ln.Addr().String(), -5*time.Second) // in the past
if err == nil {
defer c.Close()
}
if !isTimeout(err) {
t.Fatalf("DialTimeout: got %v; want timeout", err)
}
}
// TestProlongTimeout tests concurrent deadline modification.
// Known to cause data races in the past.
func TestProlongTimeout(t *testing.T) {