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// 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.
//go:build unix
package net
import (
"context"
"internal/poll"
"os"
"runtime"
"syscall"
)
const (
readSyscallName = "read"
readFromSyscallName = "recvfrom"
readMsgSyscallName = "recvmsg"
writeSyscallName = "write"
writeToSyscallName = "sendto"
writeMsgSyscallName = "sendmsg"
)
func newFD(sysfd, family, sotype int, net string) (*netFD, error) {
ret := &netFD{
pfd: poll.FD{
Sysfd: sysfd,
IsStream: sotype == syscall.SOCK_STREAM,
ZeroReadIsEOF: sotype != syscall.SOCK_DGRAM && sotype != syscall.SOCK_RAW,
},
family: family,
sotype: sotype,
net: net,
}
return ret, nil
}
func (fd *netFD) init() error {
return fd.pfd.Init(fd.net, true)
}
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(ctx context.Context, la, ra syscall.Sockaddr) (rsa syscall.Sockaddr, ret error) {
// Do not need to call fd.writeLock here,
// because fd is not yet accessible to user,
// so no concurrent operations are possible.
switch err := connectFunc(fd.pfd.Sysfd, ra); err {
case syscall.EINPROGRESS, syscall.EALREADY, syscall.EINTR:
case nil, syscall.EISCONN:
select {
case <-ctx.Done():
return nil, mapErr(ctx.Err())
default:
}
if err := fd.pfd.Init(fd.net, true); err != nil {
return nil, err
}
runtime.KeepAlive(fd)
return nil, nil
case syscall.EINVAL:
// On Solaris and illumos 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
// https://golang.org/issue/6828.
if runtime.GOOS == "solaris" || runtime.GOOS == "illumos" {
return nil, nil
}
fallthrough
default:
return nil, os.NewSyscallError("connect", err)
}
if err := fd.pfd.Init(fd.net, true); err != nil {
return nil, err
}
if deadline, hasDeadline := ctx.Deadline(); hasDeadline {
fd.pfd.SetWriteDeadline(deadline)
defer fd.pfd.SetWriteDeadline(noDeadline)
}
// Start the "interrupter" goroutine, if this context might be canceled.
//
// The interrupter goroutine waits for the context to be done and
// interrupts the dial (by altering the fd's write deadline, which
// wakes up waitWrite).
ctxDone := ctx.Done()
if ctxDone != nil {
// Wait for the interrupter goroutine to exit before returning
// from connect.
done := make(chan struct{})
interruptRes := make(chan error)
defer func() {
close(done)
if ctxErr := <-interruptRes; ctxErr != nil && ret == nil {
// The interrupter goroutine called SetWriteDeadline,
// but the connect code below had returned from
// waitWrite already and did a successful connect (ret
// == nil). Because we've now poisoned the connection
// by making it unwritable, don't return a successful
// dial. This was issue 16523.
ret = mapErr(ctxErr)
fd.Close() // prevent a leak
}
}()
go func() {
select {
case <-ctxDone:
// Force the runtime's poller to immediately give up
// waiting for writability, unblocking waitWrite
// below.
fd.pfd.SetWriteDeadline(aLongTimeAgo)
testHookCanceledDial()
interruptRes <- ctx.Err()
case <-done:
interruptRes <- nil
}
}()
}
for {
// Performing multiple connect system calls on a
// non-blocking socket under Unix variants does not
// necessarily result in earlier errors being
// returned. Instead, once runtime-integrated network
// poller tells us that the socket is ready, get the
// SO_ERROR socket option to see if the connection
// succeeded or failed. See issue 7474 for further
// details.
if err := fd.pfd.WaitWrite(); err != nil {
select {
case <-ctxDone:
return nil, mapErr(ctx.Err())
default:
}
return nil, err
}
nerr, err := getsockoptIntFunc(fd.pfd.Sysfd, syscall.SOL_SOCKET, syscall.SO_ERROR)
if err != nil {
return nil, os.NewSyscallError("getsockopt", err)
}
switch err := syscall.Errno(nerr); err {
case syscall.EINPROGRESS, syscall.EALREADY, syscall.EINTR:
case syscall.EISCONN:
return nil, nil
case syscall.Errno(0):
// The runtime poller can wake us up spuriously;
// see issues 14548 and 19289. Check that we are
// really connected; if not, wait again.
if rsa, err := syscall.Getpeername(fd.pfd.Sysfd); err == nil {
return rsa, nil
}
default:
return nil, os.NewSyscallError("connect", err)
}
runtime.KeepAlive(fd)
}
}
func (fd *netFD) accept() (netfd *netFD, err error) {
d, rsa, errcall, err := fd.pfd.Accept()
if err != nil {
if errcall != "" {
err = wrapSyscallError(errcall, err)
}
return nil, err
}
if netfd, err = newFD(d, fd.family, fd.sotype, fd.net); err != nil {
poll.CloseFunc(d)
return nil, err
}
if err = netfd.init(); err != nil {
netfd.Close()
return nil, err
}
lsa, _ := syscall.Getsockname(netfd.pfd.Sysfd)
netfd.setAddr(netfd.addrFunc()(lsa), netfd.addrFunc()(rsa))
return netfd, nil
}
// Defined in os package.
func newUnixFile(fd uintptr, name string) *os.File
func (fd *netFD) dup() (f *os.File, err error) {
ns, call, err := fd.pfd.Dup()
if err != nil {
if call != "" {
err = os.NewSyscallError(call, err)
}
return nil, err
}
return newUnixFile(uintptr(ns), fd.name()), nil
}
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