gcc/libgo/go/net/fd_unix.go
Ian Lance Taylor f89b66f5ad net: work around Solaris connect issue when server closes socket
On Solaris, if you do a in-progress connect, and then the
server accepts and closes the socket, the client's later
attempt to complete the connect will fail with EINVAL.  Handle
this case by assuming that the connect succeeded.  This code
is weird enough that it is implemented as Solaris-only so that
it doesn't hide a real error on a different OS.

See http://golang.org/issue/6828.

From-SVN: r206232
2013-12-28 18:00:30 +00:00

493 lines
11 KiB
Go

// Copyright 2009 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 darwin dragonfly freebsd linux netbsd openbsd
package net
import (
"io"
"os"
"runtime"
"sync/atomic"
"syscall"
"time"
)
// Network file descriptor.
type netFD struct {
// locking/lifetime of sysfd + serialize access to Read and Write methods
fdmu fdMutex
// immutable until Close
sysfd int
family int
sotype int
isConnected bool
net string
laddr Addr
raddr Addr
// wait server
pd pollDesc
}
func sysInit() {
}
func dial(network string, ra Addr, dialer func(time.Time) (Conn, error), deadline time.Time) (Conn, error) {
return dialer(deadline)
}
func newFD(sysfd, family, sotype int, net string) (*netFD, error) {
return &netFD{sysfd: sysfd, family: family, sotype: sotype, net: net}, nil
}
func (fd *netFD) init() error {
if err := fd.pd.Init(fd); err != nil {
return err
}
return nil
}
func (fd *netFD) setAddr(laddr, raddr Addr) {
fd.laddr = laddr
fd.raddr = raddr
runtime.SetFinalizer(fd, (*netFD).Close)
}
func (fd *netFD) name() string {
var ls, rs string
if fd.laddr != nil {
ls = fd.laddr.String()
}
if fd.raddr != nil {
rs = fd.raddr.String()
}
return fd.net + ":" + ls + "->" + rs
}
func (fd *netFD) connect(la, ra syscall.Sockaddr) 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
}
for {
err := syscall.Connect(fd.sysfd, ra)
if err == nil || err == syscall.EISCONN {
break
}
// On Solaris we can see EINVAL if the socket has
// already been accepted and closed by the server.
// Treat this as a successful connection--writes to
// the socket will see EOF. For details and a test
// case in C see http://golang.org/issue/6828.
if runtime.GOOS == "solaris" && err == syscall.EINVAL {
break
}
if err != syscall.EINPROGRESS && err != syscall.EALREADY && err != syscall.EINTR {
return err
}
if err = fd.pd.WaitWrite(); err != nil {
return err
}
}
return nil
}
func (fd *netFD) destroy() {
// Poller may want to unregister fd in readiness notification mechanism,
// so this must be executed before closesocket.
fd.pd.Close()
closesocket(fd.sysfd)
fd.sysfd = -1
runtime.SetFinalizer(fd, nil)
}
// Add a reference to this fd.
// Returns an error if the fd cannot be used.
func (fd *netFD) incref() error {
if !fd.fdmu.Incref() {
return errClosing
}
return nil
}
// Remove a reference to this FD and close if we've been asked to do so
// (and there are no references left).
func (fd *netFD) decref() {
if fd.fdmu.Decref() {
fd.destroy()
}
}
// Add a reference to this fd and lock for reading.
// Returns an error if the fd cannot be used.
func (fd *netFD) readLock() error {
if !fd.fdmu.RWLock(true) {
return errClosing
}
return nil
}
// Unlock for reading and remove a reference to this FD.
func (fd *netFD) readUnlock() {
if fd.fdmu.RWUnlock(true) {
fd.destroy()
}
}
// Add a reference to this fd and lock for writing.
// Returns an error if the fd cannot be used.
func (fd *netFD) writeLock() error {
if !fd.fdmu.RWLock(false) {
return errClosing
}
return nil
}
// Unlock for writing and remove a reference to this FD.
func (fd *netFD) writeUnlock() {
if fd.fdmu.RWUnlock(false) {
fd.destroy()
}
}
func (fd *netFD) Close() error {
fd.pd.Lock() // needed for both fd.incref(true) and pollDesc.Evict
if !fd.fdmu.IncrefAndClose() {
fd.pd.Unlock()
return errClosing
}
// Unblock any I/O. Once it all unblocks and returns,
// so that it cannot be referring to fd.sysfd anymore,
// the final decref will close fd.sysfd. This should happen
// fairly quickly, since all the I/O is non-blocking, and any
// attempts to block in the pollDesc will return errClosing.
doWakeup := fd.pd.Evict()
fd.pd.Unlock()
fd.decref()
if doWakeup {
fd.pd.Wakeup()
}
return nil
}
func (fd *netFD) shutdown(how int) error {
if err := fd.incref(); err != nil {
return err
}
defer fd.decref()
err := syscall.Shutdown(fd.sysfd, how)
if err != nil {
return &OpError{"shutdown", fd.net, fd.laddr, err}
}
return nil
}
func (fd *netFD) CloseRead() error {
return fd.shutdown(syscall.SHUT_RD)
}
func (fd *netFD) CloseWrite() error {
return fd.shutdown(syscall.SHUT_WR)
}
func (fd *netFD) Read(p []byte) (n int, err error) {
if err := fd.readLock(); err != nil {
return 0, err
}
defer fd.readUnlock()
if err := fd.pd.PrepareRead(); err != nil {
return 0, &OpError{"read", fd.net, fd.raddr, err}
}
for {
n, err = syscall.Read(int(fd.sysfd), p)
if err != nil {
n = 0
if err == syscall.EAGAIN {
if err = fd.pd.WaitRead(); err == nil {
continue
}
}
}
err = chkReadErr(n, err, fd)
break
}
if err != nil && err != io.EOF {
err = &OpError{"read", fd.net, fd.raddr, err}
}
return
}
func (fd *netFD) ReadFrom(p []byte) (n int, sa syscall.Sockaddr, err error) {
if err := fd.readLock(); err != nil {
return 0, nil, err
}
defer fd.readUnlock()
if err := fd.pd.PrepareRead(); err != nil {
return 0, nil, &OpError{"read", fd.net, fd.laddr, err}
}
for {
n, sa, err = syscall.Recvfrom(fd.sysfd, p, 0)
if err != nil {
n = 0
if err == syscall.EAGAIN {
if err = fd.pd.WaitRead(); err == nil {
continue
}
}
}
err = chkReadErr(n, err, fd)
break
}
if err != nil && err != io.EOF {
err = &OpError{"read", fd.net, fd.laddr, err}
}
return
}
func (fd *netFD) ReadMsg(p []byte, oob []byte) (n, oobn, flags int, sa syscall.Sockaddr, err error) {
if err := fd.readLock(); err != nil {
return 0, 0, 0, nil, err
}
defer fd.readUnlock()
if err := fd.pd.PrepareRead(); err != nil {
return 0, 0, 0, nil, &OpError{"read", fd.net, fd.laddr, err}
}
for {
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
if err == syscall.EAGAIN {
if err = fd.pd.WaitRead(); err == nil {
continue
}
}
}
err = chkReadErr(n, err, fd)
break
}
if err != nil && err != io.EOF {
err = &OpError{"read", fd.net, fd.laddr, err}
}
return
}
func chkReadErr(n int, err error, fd *netFD) error {
if n == 0 && err == nil && fd.sotype != syscall.SOCK_DGRAM && fd.sotype != syscall.SOCK_RAW {
return io.EOF
}
return err
}
func (fd *netFD) Write(p []byte) (nn int, err error) {
if err := fd.writeLock(); err != nil {
return 0, err
}
defer fd.writeUnlock()
if err := fd.pd.PrepareWrite(); err != nil {
return 0, &OpError{"write", fd.net, fd.raddr, err}
}
for {
var n int
n, err = syscall.Write(int(fd.sysfd), p[nn:])
if n > 0 {
nn += n
}
if nn == len(p) {
break
}
if err == syscall.EAGAIN {
if err = fd.pd.WaitWrite(); err == nil {
continue
}
}
if err != nil {
n = 0
break
}
if n == 0 {
err = io.ErrUnexpectedEOF
break
}
}
if err != nil {
err = &OpError{"write", fd.net, fd.raddr, err}
}
return nn, err
}
func (fd *netFD) WriteTo(p []byte, sa syscall.Sockaddr) (n int, err error) {
if err := fd.writeLock(); err != nil {
return 0, err
}
defer fd.writeUnlock()
if err := fd.pd.PrepareWrite(); err != nil {
return 0, &OpError{"write", fd.net, fd.raddr, err}
}
for {
err = syscall.Sendto(fd.sysfd, p, 0, sa)
if err == syscall.EAGAIN {
if err = fd.pd.WaitWrite(); err == nil {
continue
}
}
break
}
if err == nil {
n = len(p)
} else {
err = &OpError{"write", fd.net, fd.raddr, err}
}
return
}
func (fd *netFD) WriteMsg(p []byte, oob []byte, sa syscall.Sockaddr) (n int, oobn int, err error) {
if err := fd.writeLock(); err != nil {
return 0, 0, err
}
defer fd.writeUnlock()
if err := fd.pd.PrepareWrite(); err != nil {
return 0, 0, &OpError{"write", fd.net, fd.raddr, err}
}
for {
err = syscall.Sendmsg(fd.sysfd, p, oob, sa, 0)
if err == syscall.EAGAIN {
if err = fd.pd.WaitWrite(); err == nil {
continue
}
}
break
}
if err == nil {
n = len(p)
oobn = len(oob)
} else {
err = &OpError{"write", fd.net, fd.raddr, err}
}
return
}
func (fd *netFD) accept(toAddr func(syscall.Sockaddr) Addr) (netfd *netFD, err error) {
if err := fd.readLock(); err != nil {
return nil, err
}
defer fd.readUnlock()
var s int
var rsa syscall.Sockaddr
if err = fd.pd.PrepareRead(); err != nil {
return nil, &OpError{"accept", fd.net, fd.laddr, err}
}
for {
s, rsa, err = accept(fd.sysfd)
if err != nil {
if err == syscall.EAGAIN {
if err = fd.pd.WaitRead(); err == nil {
continue
}
} else if err == syscall.ECONNABORTED {
// This means that a socket on the listen queue was closed
// before we Accept()ed it; it's a silly error, so try again.
continue
}
return nil, &OpError{"accept", fd.net, fd.laddr, err}
}
break
}
if netfd, err = newFD(s, fd.family, fd.sotype, fd.net); err != nil {
closesocket(s)
return nil, err
}
if err = netfd.init(); err != nil {
fd.Close()
return nil, err
}
lsa, _ := syscall.Getsockname(netfd.sysfd)
netfd.setAddr(toAddr(lsa), toAddr(rsa))
return netfd, nil
}
// tryDupCloexec indicates whether F_DUPFD_CLOEXEC should be used.
// If the kernel doesn't support it, this is set to 0.
var tryDupCloexec = int32(1)
func dupCloseOnExec(fd int) (newfd int, err error) {
if atomic.LoadInt32(&tryDupCloexec) == 1 && syscall.F_DUPFD_CLOEXEC != 0 {
r0, _, e1 := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_DUPFD_CLOEXEC, 0)
if runtime.GOOS == "darwin" && e1 == syscall.EBADF {
// On OS X 10.6 and below (but we only support
// >= 10.6), F_DUPFD_CLOEXEC is unsupported
// and fcntl there falls back (undocumented)
// to doing an ioctl instead, returning EBADF
// in this case because fd is not of the
// expected device fd type. Treat it as
// EINVAL instead, so we fall back to the
// normal dup path.
// TODO: only do this on 10.6 if we can detect 10.6
// cheaply.
e1 = syscall.EINVAL
}
switch e1 {
case 0:
return int(r0), nil
case syscall.EINVAL:
// Old kernel. Fall back to the portable way
// from now on.
atomic.StoreInt32(&tryDupCloexec, 0)
default:
return -1, e1
}
}
return dupCloseOnExecOld(fd)
}
// dupCloseOnExecUnixOld is the traditional way to dup an fd and
// set its O_CLOEXEC bit, using two system calls.
func dupCloseOnExecOld(fd int) (newfd int, err error) {
syscall.ForkLock.RLock()
defer syscall.ForkLock.RUnlock()
newfd, err = syscall.Dup(fd)
if err != nil {
return -1, err
}
syscall.CloseOnExec(newfd)
return
}
func (fd *netFD) dup() (f *os.File, err error) {
ns, err := dupCloseOnExec(fd.sysfd)
if err != nil {
syscall.ForkLock.RUnlock()
return nil, &OpError{"dup", fd.net, fd.laddr, err}
}
// We want blocking mode for the new fd, hence the double negative.
// This also puts the old fd into blocking mode, meaning that
// I/O will block the thread instead of letting us use the epoll server.
// Everything will still work, just with more threads.
if err = syscall.SetNonblock(ns, false); err != nil {
return nil, &OpError{"setnonblock", fd.net, fd.laddr, err}
}
return os.NewFile(uintptr(ns), fd.name()), nil
}
func closesocket(s int) error {
return syscall.Close(s)
}
func skipRawSocketTests() (skip bool, skipmsg string, err error) {
if os.Getuid() != 0 {
return true, "skipping test; must be root", nil
}
return false, "", nil
}