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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.
// Unix domain sockets
package net
import (
"os"
"syscall"
)
func unixSocket(net string, laddr, raddr *UnixAddr, mode string) (fd *netFD, err os.Error) {
var proto int
switch net {
default:
return nil, UnknownNetworkError(net)
case "unix":
proto = syscall.SOCK_STREAM
case "unixgram":
proto = syscall.SOCK_DGRAM
case "unixpacket":
proto = syscall.SOCK_SEQPACKET
}
var la, ra syscall.Sockaddr
switch mode {
default:
panic("unixSocket mode " + mode)
case "dial":
if laddr != nil {
la = &syscall.SockaddrUnix{Name: laddr.Name}
}
if raddr != nil {
ra = &syscall.SockaddrUnix{Name: raddr.Name}
} else if proto != syscall.SOCK_DGRAM || laddr == nil {
return nil, &OpError{Op: mode, Net: net, Error: errMissingAddress}
}
case "listen":
if laddr == nil {
return nil, &OpError{mode, net, nil, errMissingAddress}
}
la = &syscall.SockaddrUnix{Name: laddr.Name}
if raddr != nil {
return nil, &OpError{Op: mode, Net: net, Addr: raddr, Error: &AddrError{Error: "unexpected remote address", Addr: raddr.String()}}
}
}
f := sockaddrToUnix
if proto == syscall.SOCK_DGRAM {
f = sockaddrToUnixgram
} else if proto == syscall.SOCK_SEQPACKET {
f = sockaddrToUnixpacket
}
fd, oserr := socket(net, syscall.AF_UNIX, proto, 0, la, ra, f)
if oserr != nil {
goto Error
}
return fd, nil
Error:
addr := raddr
if mode == "listen" {
addr = laddr
}
return nil, &OpError{Op: mode, Net: net, Addr: addr, Error: oserr}
}
// UnixAddr represents the address of a Unix domain socket end point.
type UnixAddr struct {
Name string
Net string
}
func sockaddrToUnix(sa syscall.Sockaddr) Addr {
if s, ok := sa.(*syscall.SockaddrUnix); ok {
return &UnixAddr{s.Name, "unix"}
}
return nil
}
func sockaddrToUnixgram(sa syscall.Sockaddr) Addr {
if s, ok := sa.(*syscall.SockaddrUnix); ok {
return &UnixAddr{s.Name, "unixgram"}
}
return nil
}
func sockaddrToUnixpacket(sa syscall.Sockaddr) Addr {
if s, ok := sa.(*syscall.SockaddrUnix); ok {
return &UnixAddr{s.Name, "unixpacket"}
}
return nil
}
func protoToNet(proto int) string {
switch proto {
case syscall.SOCK_STREAM:
return "unix"
case syscall.SOCK_SEQPACKET:
return "unixpacket"
case syscall.SOCK_DGRAM:
return "unixgram"
default:
panic("protoToNet unknown protocol")
}
return ""
}
// Network returns the address's network name, "unix" or "unixgram".
func (a *UnixAddr) Network() string {
return a.Net
}
func (a *UnixAddr) String() string {
if a == nil {
return "<nil>"
}
return a.Name
}
func (a *UnixAddr) toAddr() Addr {
if a == nil { // nil *UnixAddr
return nil // nil interface
}
return a
}
// ResolveUnixAddr parses addr as a Unix domain socket address.
// The string net gives the network name, "unix", "unixgram" or
// "unixpacket".
func ResolveUnixAddr(net, addr string) (*UnixAddr, os.Error) {
switch net {
case "unix":
case "unixpacket":
case "unixgram":
default:
return nil, UnknownNetworkError(net)
}
return &UnixAddr{addr, net}, nil
}
// UnixConn is an implementation of the Conn interface
// for connections to Unix domain sockets.
type UnixConn struct {
fd *netFD
}
func newUnixConn(fd *netFD) *UnixConn { return &UnixConn{fd} }
func (c *UnixConn) ok() bool { return c != nil && c.fd != nil }
// Implementation of the Conn interface - see Conn for documentation.
// Read implements the net.Conn Read method.
func (c *UnixConn) Read(b []byte) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
return c.fd.Read(b)
}
// Write implements the net.Conn Write method.
func (c *UnixConn) Write(b []byte) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
return c.fd.Write(b)
}
// Close closes the Unix domain connection.
func (c *UnixConn) Close() os.Error {
if !c.ok() {
return os.EINVAL
}
err := c.fd.Close()
c.fd = nil
return err
}
// LocalAddr returns the local network address, a *UnixAddr.
// Unlike in other protocols, LocalAddr is usually nil for dialed connections.
func (c *UnixConn) LocalAddr() Addr {
if !c.ok() {
return nil
}
return c.fd.laddr
}
// RemoteAddr returns the remote network address, a *UnixAddr.
// Unlike in other protocols, RemoteAddr is usually nil for connections
// accepted by a listener.
func (c *UnixConn) RemoteAddr() Addr {
if !c.ok() {
return nil
}
return c.fd.raddr
}
// SetTimeout implements the net.Conn SetTimeout method.
func (c *UnixConn) SetTimeout(nsec int64) os.Error {
if !c.ok() {
return os.EINVAL
}
return setTimeout(c.fd, nsec)
}
// SetReadTimeout implements the net.Conn SetReadTimeout method.
func (c *UnixConn) SetReadTimeout(nsec int64) os.Error {
if !c.ok() {
return os.EINVAL
}
return setReadTimeout(c.fd, nsec)
}
// SetWriteTimeout implements the net.Conn SetWriteTimeout method.
func (c *UnixConn) SetWriteTimeout(nsec int64) os.Error {
if !c.ok() {
return os.EINVAL
}
return setWriteTimeout(c.fd, nsec)
}
// SetReadBuffer sets the size of the operating system's
// receive buffer associated with the connection.
func (c *UnixConn) SetReadBuffer(bytes int) os.Error {
if !c.ok() {
return os.EINVAL
}
return setReadBuffer(c.fd, bytes)
}
// SetWriteBuffer sets the size of the operating system's
// transmit buffer associated with the connection.
func (c *UnixConn) SetWriteBuffer(bytes int) os.Error {
if !c.ok() {
return os.EINVAL
}
return setWriteBuffer(c.fd, bytes)
}
// ReadFromUnix reads a packet from c, copying the payload into b.
// It returns the number of bytes copied into b and the return address
// that was on the packet.
//
// ReadFromUnix can be made to time out and return
// an error with Timeout() == true after a fixed time limit;
// see SetTimeout and SetReadTimeout.
func (c *UnixConn) ReadFromUnix(b []byte) (n int, addr *UnixAddr, err os.Error) {
if !c.ok() {
return 0, nil, os.EINVAL
}
n, sa, err := c.fd.ReadFrom(b)
switch sa := sa.(type) {
case *syscall.SockaddrUnix:
addr = &UnixAddr{sa.Name, protoToNet(c.fd.proto)}
}
return
}
// ReadFrom implements the net.PacketConn ReadFrom method.
func (c *UnixConn) ReadFrom(b []byte) (n int, addr Addr, err os.Error) {
if !c.ok() {
return 0, nil, os.EINVAL
}
n, uaddr, err := c.ReadFromUnix(b)
return n, uaddr.toAddr(), err
}
// WriteToUnix writes a packet to addr via c, copying the payload from b.
//
// WriteToUnix can be made to time out and return
// an error with Timeout() == true after a fixed time limit;
// see SetTimeout and SetWriteTimeout.
// On packet-oriented connections, write timeouts are rare.
func (c *UnixConn) WriteToUnix(b []byte, addr *UnixAddr) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
if addr.Net != protoToNet(c.fd.proto) {
return 0, os.EAFNOSUPPORT
}
sa := &syscall.SockaddrUnix{Name: addr.Name}
return c.fd.WriteTo(b, sa)
}
// WriteTo implements the net.PacketConn WriteTo method.
func (c *UnixConn) WriteTo(b []byte, addr Addr) (n int, err os.Error) {
if !c.ok() {
return 0, os.EINVAL
}
a, ok := addr.(*UnixAddr)
if !ok {
return 0, &OpError{"writeto", "unix", addr, os.EINVAL}
}
return c.WriteToUnix(b, a)
}
func (c *UnixConn) ReadMsgUnix(b, oob []byte) (n, oobn, flags int, addr *UnixAddr, err os.Error) {
if !c.ok() {
return 0, 0, 0, nil, os.EINVAL
}
n, oobn, flags, sa, err := c.fd.ReadMsg(b, oob)
switch sa := sa.(type) {
case *syscall.SockaddrUnix:
addr = &UnixAddr{sa.Name, protoToNet(c.fd.proto)}
}
return
}
func (c *UnixConn) WriteMsgUnix(b, oob []byte, addr *UnixAddr) (n, oobn int, err os.Error) {
if !c.ok() {
return 0, 0, os.EINVAL
}
if addr != nil {
if addr.Net != protoToNet(c.fd.proto) {
return 0, 0, os.EAFNOSUPPORT
}
sa := &syscall.SockaddrUnix{Name: addr.Name}
return c.fd.WriteMsg(b, oob, sa)
}
return c.fd.WriteMsg(b, oob, nil)
}
// File returns a copy of the underlying os.File, set to blocking mode.
// It is the caller's responsibility to close f when finished.
// Closing c does not affect f, and closing f does not affect c.
func (c *UnixConn) File() (f *os.File, err os.Error) { return c.fd.dup() }
// DialUnix connects to the remote address raddr on the network net,
// which must be "unix" or "unixgram". If laddr is not nil, it is used
// as the local address for the connection.
func DialUnix(net string, laddr, raddr *UnixAddr) (c *UnixConn, err os.Error) {
fd, e := unixSocket(net, laddr, raddr, "dial")
if e != nil {
return nil, e
}
return newUnixConn(fd), nil
}
// UnixListener is a Unix domain socket listener.
// Clients should typically use variables of type Listener
// instead of assuming Unix domain sockets.
type UnixListener struct {
fd *netFD
path string
}
// ListenUnix announces on the Unix domain socket laddr and returns a Unix listener.
// Net must be "unix" (stream sockets).
func ListenUnix(net string, laddr *UnixAddr) (l *UnixListener, err os.Error) {
if net != "unix" && net != "unixgram" && net != "unixpacket" {
return nil, UnknownNetworkError(net)
}
if laddr != nil {
laddr = &UnixAddr{laddr.Name, net} // make our own copy
}
fd, err := unixSocket(net, laddr, nil, "listen")
if err != nil {
return nil, err
}
e1 := syscall.Listen(fd.sysfd, 8) // listenBacklog());
if e1 != 0 {
closesocket(fd.sysfd)
return nil, &OpError{Op: "listen", Net: "unix", Addr: laddr, Error: os.Errno(e1)}
}
return &UnixListener{fd, laddr.Name}, nil
}
// AcceptUnix accepts the next incoming call and returns the new connection
// and the remote address.
func (l *UnixListener) AcceptUnix() (c *UnixConn, err os.Error) {
if l == nil || l.fd == nil {
return nil, os.EINVAL
}
fd, e := l.fd.accept(sockaddrToUnix)
if e != nil {
return nil, e
}
c = newUnixConn(fd)
return c, nil
}
// Accept implements the Accept method in the Listener interface;
// it waits for the next call and returns a generic Conn.
func (l *UnixListener) Accept() (c Conn, err os.Error) {
c1, err := l.AcceptUnix()
if err != nil {
return nil, err
}
return c1, nil
}
// Close stops listening on the Unix address.
// Already accepted connections are not closed.
func (l *UnixListener) Close() os.Error {
if l == nil || l.fd == nil {
return os.EINVAL
}
// The operating system doesn't clean up
// the file that announcing created, so
// we have to clean it up ourselves.
// There's a race here--we can't know for
// sure whether someone else has come along
// and replaced our socket name already--
// but this sequence (remove then close)
// is at least compatible with the auto-remove
// sequence in ListenUnix. It's only non-Go
// programs that can mess us up.
if l.path[0] != '@' {
syscall.Unlink(l.path)
}
err := l.fd.Close()
l.fd = nil
return err
}
// Addr returns the listener's network address.
func (l *UnixListener) Addr() Addr { return l.fd.laddr }
// File returns a copy of the underlying os.File, set to blocking mode.
// It is the caller's responsibility to close f when finished.
// Closing c does not affect f, and closing f does not affect c.
func (l *UnixListener) File() (f *os.File, err os.Error) { return l.fd.dup() }
// ListenUnixgram listens for incoming Unix datagram packets addressed to the
// local address laddr. The returned connection c's ReadFrom
// and WriteTo methods can be used to receive and send UDP
// packets with per-packet addressing. The network net must be "unixgram".
func ListenUnixgram(net string, laddr *UnixAddr) (c *UDPConn, err os.Error) {
switch net {
case "unixgram":
default:
return nil, UnknownNetworkError(net)
}
if laddr == nil {
return nil, &OpError{"listen", "unixgram", nil, errMissingAddress}
}
fd, e := unixSocket(net, laddr, nil, "listen")
if e != nil {
return nil, e
}
return newUDPConn(fd), nil
}