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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.
package net
import (
"io"
"os"
"syscall"
"time"
)
// Network file descriptor.
type netFD struct {
// locking/lifetime of sysfd + serialize access to Read and Write methods
fdmu fdMutex
// immutable until Close
net string
n string
dir string
ctl, data *os.File
laddr, raddr Addr
}
var (
netdir string // default network
)
func sysInit() {
netdir = "/net"
}
func newFD(net, name string, ctl, data *os.File, laddr, raddr Addr) (*netFD, error) {
return &netFD{net: net, n: name, dir: netdir + "/" + net + "/" + name, ctl: ctl, data: data, laddr: laddr, raddr: raddr}, nil
}
func (fd *netFD) init() error {
// stub for future fd.pd.Init(fd)
return nil
}
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) ok() bool { return fd != nil && fd.ctl != nil }
func (fd *netFD) destroy() {
if !fd.ok() {
return
}
err := fd.ctl.Close()
if fd.data != nil {
if err1 := fd.data.Close(); err1 != nil && err == nil {
err = err1
}
}
fd.ctl = nil
fd.data = nil
}
func (fd *netFD) Read(b []byte) (n int, err error) {
if !fd.ok() || fd.data == nil {
return 0, syscall.EINVAL
}
if err := fd.readLock(); err != nil {
return 0, err
}
defer fd.readUnlock()
n, err = fd.data.Read(b)
if fd.net == "udp" && err == io.EOF {
n = 0
err = nil
}
return
}
func (fd *netFD) Write(b []byte) (n int, err error) {
if !fd.ok() || fd.data == nil {
return 0, syscall.EINVAL
}
if err := fd.writeLock(); err != nil {
return 0, err
}
defer fd.writeUnlock()
return fd.data.Write(b)
}
func (fd *netFD) closeRead() error {
if !fd.ok() {
return syscall.EINVAL
}
return syscall.EPLAN9
}
func (fd *netFD) closeWrite() error {
if !fd.ok() {
return syscall.EINVAL
}
return syscall.EPLAN9
}
func (fd *netFD) Close() error {
if !fd.fdmu.increfAndClose() {
return errClosing
}
if !fd.ok() {
return syscall.EINVAL
}
if fd.net == "tcp" {
// The following line is required to unblock Reads.
// For some reason, WriteString returns an error:
// "write /net/tcp/39/listen: inappropriate use of fd"
// But without it, Reads on dead conns hang forever.
// See Issue 9554.
fd.ctl.WriteString("hangup")
}
err := fd.ctl.Close()
if fd.data != nil {
if err1 := fd.data.Close(); err1 != nil && err == nil {
err = err1
}
}
fd.ctl = nil
fd.data = nil
return err
}
// This method is only called via Conn.
func (fd *netFD) dup() (*os.File, error) {
if !fd.ok() || fd.data == nil {
return nil, syscall.EINVAL
}
return fd.file(fd.data, fd.dir+"/data")
}
func (l *TCPListener) dup() (*os.File, error) {
if !l.fd.ok() {
return nil, syscall.EINVAL
}
return l.fd.file(l.fd.ctl, l.fd.dir+"/ctl")
}
func (fd *netFD) file(f *os.File, s string) (*os.File, error) {
syscall.ForkLock.RLock()
dfd, err := syscall.Dup(int(f.Fd()), -1)
syscall.ForkLock.RUnlock()
if err != nil {
return nil, os.NewSyscallError("dup", err)
}
return os.NewFile(uintptr(dfd), s), nil
}
func (fd *netFD) setDeadline(t time.Time) error {
return syscall.EPLAN9
}
func (fd *netFD) setReadDeadline(t time.Time) error {
return syscall.EPLAN9
}
func (fd *netFD) setWriteDeadline(t time.Time) error {
return syscall.EPLAN9
}
func setReadBuffer(fd *netFD, bytes int) error {
return syscall.EPLAN9
}
func setWriteBuffer(fd *netFD, bytes int) error {
return syscall.EPLAN9
}
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