libgo/go/net/unixsock.go

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package net
   6
   7 import (
   8         "context"
   9         "os"
  10         "sync"
  11         "syscall"
  12         "time"
  13 )
  14
  15 // UnixAddr represents the address of a Unix domain socket end point.
  16 type UnixAddr struct {
  17         Name string
  18         Net  string
  19 }
  20
  21 // Network returns the address's network name, "unix", "unixgram" or
  22 // "unixpacket".
  23 func (a *UnixAddr) Network() string {
  24         return a.Net
  25 }
  26
  27 func (a *UnixAddr) String() string {
  28         if a == nil {
  29                 return "<nil>"
  30         }
  31         return a.Name
  32 }
  33
  34 func (a *UnixAddr) isWildcard() bool {
  35         return a == nil || a.Name == ""
  36 }
  37
  38 func (a *UnixAddr) opAddr() Addr {
  39         if a == nil {
  40                 return nil
  41         }
  42         return a
  43 }
  44
  45 // ResolveUnixAddr parses addr as a Unix domain socket address.
  46 // The string net gives the network name, "unix", "unixgram" or
  47 // "unixpacket".
  48 func ResolveUnixAddr(net, addr string) (*UnixAddr, error) {
  49         switch net {
  50         case "unix", "unixgram", "unixpacket":
  51                 return &UnixAddr{Name: addr, Net: net}, nil
  52         default:
  53                 return nil, UnknownNetworkError(net)
  54         }
  55 }
  56
  57 // UnixConn is an implementation of the Conn interface for connections
  58 // to Unix domain sockets.
  59 type UnixConn struct {
  60         conn
  61 }
  62
  63 // CloseRead shuts down the reading side of the Unix domain connection.
  64 // Most callers should just use Close.
  65 func (c *UnixConn) CloseRead() error {
  66         if !c.ok() {
  67                 return syscall.EINVAL
  68         }
  69         if err := c.fd.closeRead(); err != nil {
  70                 return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
  71         }
  72         return nil
  73 }
  74
  75 // CloseWrite shuts down the writing side of the Unix domain connection.
  76 // Most callers should just use Close.
  77 func (c *UnixConn) CloseWrite() error {
  78         if !c.ok() {
  79                 return syscall.EINVAL
  80         }
  81         if err := c.fd.closeWrite(); err != nil {
  82                 return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
  83         }
  84         return nil
  85 }
  86
  87 // ReadFromUnix reads a packet from c, copying the payload into b. It
  88 // returns the number of bytes copied into b and the source address of
  89 // the packet.
  90 //
  91 // ReadFromUnix can be made to time out and return an error with
  92 // Timeout() == true after a fixed time limit; see SetDeadline and
  93 // SetReadDeadline.
  94 func (c *UnixConn) ReadFromUnix(b []byte) (int, *UnixAddr, error) {
  95         if !c.ok() {
  96                 return 0, nil, syscall.EINVAL
  97         }
  98         n, addr, err := c.readFrom(b)
  99         if err != nil {
 100                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 101         }
 102         return n, addr, err
 103 }
 104
 105 // ReadFrom implements the PacketConn ReadFrom method.
 106 func (c *UnixConn) ReadFrom(b []byte) (int, Addr, error) {
 107         if !c.ok() {
 108                 return 0, nil, syscall.EINVAL
 109         }
 110         n, addr, err := c.readFrom(b)
 111         if err != nil {
 112                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 113         }
 114         if addr == nil {
 115                 return n, nil, err
 116         }
 117         return n, addr, err
 118 }
 119
 120 // ReadMsgUnix reads a packet from c, copying the payload into b and
 121 // the associated out-of-band data into oob. It returns the number of
 122 // bytes copied into b, the number of bytes copied into oob, the flags
 123 // that were set on the packet, and the source address of the packet.
 124 //
 125 // Note that if len(b) == 0 and len(oob) > 0, this function will still
 126 // read (and discard) 1 byte from the connection.
 127 func (c *UnixConn) ReadMsgUnix(b, oob []byte) (n, oobn, flags int, addr *UnixAddr, err error) {
 128         if !c.ok() {
 129                 return 0, 0, 0, nil, syscall.EINVAL
 130         }
 131         n, oobn, flags, addr, err = c.readMsg(b, oob)
 132         if err != nil {
 133                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 134         }
 135         return
 136 }
 137
 138 // WriteToUnix writes a packet to addr via c, copying the payload from b.
 139 //
 140 // WriteToUnix can be made to time out and return an error with
 141 // Timeout() == true after a fixed time limit; see SetDeadline and
 142 // SetWriteDeadline. On packet-oriented connections, write timeouts
 143 // are rare.
 144 func (c *UnixConn) WriteToUnix(b []byte, addr *UnixAddr) (int, error) {
 145         if !c.ok() {
 146                 return 0, syscall.EINVAL
 147         }
 148         n, err := c.writeTo(b, addr)
 149         if err != nil {
 150                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 151         }
 152         return n, err
 153 }
 154
 155 // WriteTo implements the PacketConn WriteTo method.
 156 func (c *UnixConn) WriteTo(b []byte, addr Addr) (int, error) {
 157         if !c.ok() {
 158                 return 0, syscall.EINVAL
 159         }
 160         a, ok := addr.(*UnixAddr)
 161         if !ok {
 162                 return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
 163         }
 164         n, err := c.writeTo(b, a)
 165         if err != nil {
 166                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
 167         }
 168         return n, err
 169 }
 170
 171 // WriteMsgUnix writes a packet to addr via c, copying the payload
 172 // from b and the associated out-of-band data from oob. It returns
 173 // the number of payload and out-of-band bytes written.
 174 //
 175 // Note that if len(b) == 0 and len(oob) > 0, this function will still
 176 // write 1 byte to the connection.
 177 func (c *UnixConn) WriteMsgUnix(b, oob []byte, addr *UnixAddr) (n, oobn int, err error) {
 178         if !c.ok() {
 179                 return 0, 0, syscall.EINVAL
 180         }
 181         n, oobn, err = c.writeMsg(b, oob, addr)
 182         if err != nil {
 183                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 184         }
 185         return
 186 }
 187
 188 func newUnixConn(fd *netFD) *UnixConn { return &UnixConn{conn{fd}} }
 189
 190 // DialUnix connects to the remote address raddr on the network net,
 191 // which must be "unix", "unixgram" or "unixpacket".  If laddr is not
 192 // nil, it is used as the local address for the connection.
 193 func DialUnix(net string, laddr, raddr *UnixAddr) (*UnixConn, error) {
 194         switch net {
 195         case "unix", "unixgram", "unixpacket":
 196         default:
 197                 return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(net)}
 198         }
 199         c, err := dialUnix(context.Background(), net, laddr, raddr)
 200         if err != nil {
 201                 return nil, &OpError{Op: "dial", Net: net, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 202         }
 203         return c, nil
 204 }
 205
 206 // UnixListener is a Unix domain socket listener. Clients should
 207 // typically use variables of type Listener instead of assuming Unix
 208 // domain sockets.
 209 type UnixListener struct {
 210         fd         *netFD
 211         path       string
 212         unlink     bool
 213         unlinkOnce sync.Once
 214 }
 215
 216 func (ln *UnixListener) ok() bool { return ln != nil && ln.fd != nil }
 217
 218 // AcceptUnix accepts the next incoming call and returns the new
 219 // connection.
 220 func (l *UnixListener) AcceptUnix() (*UnixConn, error) {
 221         if !l.ok() {
 222                 return nil, syscall.EINVAL
 223         }
 224         c, err := l.accept()
 225         if err != nil {
 226                 return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 227         }
 228         return c, nil
 229 }
 230
 231 // Accept implements the Accept method in the Listener interface.
 232 // Returned connections will be of type *UnixConn.
 233 func (l *UnixListener) Accept() (Conn, error) {
 234         if !l.ok() {
 235                 return nil, syscall.EINVAL
 236         }
 237         c, err := l.accept()
 238         if err != nil {
 239                 return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 240         }
 241         return c, nil
 242 }
 243
 244 // Close stops listening on the Unix address. Already accepted
 245 // connections are not closed.
 246 func (l *UnixListener) Close() error {
 247         if !l.ok() {
 248                 return syscall.EINVAL
 249         }
 250         if err := l.close(); err != nil {
 251                 return &OpError{Op: "close", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 252         }
 253         return nil
 254 }
 255
 256 // Addr returns the listener's network address.
 257 // The Addr returned is shared by all invocations of Addr, so
 258 // do not modify it.
 259 func (l *UnixListener) Addr() Addr { return l.fd.laddr }
 260
 261 // SetDeadline sets the deadline associated with the listener.
 262 // A zero time value disables the deadline.
 263 func (l *UnixListener) SetDeadline(t time.Time) error {
 264         if !l.ok() {
 265                 return syscall.EINVAL
 266         }
 267         if err := l.fd.setDeadline(t); err != nil {
 268                 return &OpError{Op: "set", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 269         }
 270         return nil
 271 }
 272
 273 // File returns a copy of the underlying os.File, set to blocking
 274 // mode. It is the caller's responsibility to close f when finished.
 275 // Closing l does not affect f, and closing f does not affect l.
 276 //
 277 // The returned os.File's file descriptor is different from the
 278 // connection's. Attempting to change properties of the original
 279 // using this duplicate may or may not have the desired effect.
 280 func (l *UnixListener) File() (f *os.File, err error) {
 281         if !l.ok() {
 282                 return nil, syscall.EINVAL
 283         }
 284         f, err = l.file()
 285         if err != nil {
 286                 err = &OpError{Op: "file", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 287         }
 288         return
 289 }
 290
 291 // ListenUnix announces on the Unix domain socket laddr and returns a
 292 // Unix listener. The network net must be "unix" or "unixpacket".
 293 func ListenUnix(net string, laddr *UnixAddr) (*UnixListener, error) {
 294         switch net {
 295         case "unix", "unixpacket":
 296         default:
 297                 return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)}
 298         }
 299         if laddr == nil {
 300                 return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: errMissingAddress}
 301         }
 302         ln, err := listenUnix(context.Background(), net, laddr)
 303         if err != nil {
 304                 return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: err}
 305         }
 306         return ln, nil
 307 }
 308
 309 // ListenUnixgram listens for incoming Unix datagram packets addressed
 310 // to the local address laddr. The network net must be "unixgram".
 311 // The returned connection's ReadFrom and WriteTo methods can be used
 312 // to receive and send packets with per-packet addressing.
 313 func ListenUnixgram(net string, laddr *UnixAddr) (*UnixConn, error) {
 314         switch net {
 315         case "unixgram":
 316         default:
 317                 return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(net)}
 318         }
 319         if laddr == nil {
 320                 return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: nil, Err: errMissingAddress}
 321         }
 322         c, err := listenUnixgram(context.Background(), net, laddr)
 323         if err != nil {
 324                 return nil, &OpError{Op: "listen", Net: net, Source: nil, Addr: laddr.opAddr(), Err: err}
 325         }
 326         return c, nil
 327 }