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 // BUG(mikio): On JS, NaCl, Plan 9 and Windows, methods and functions
  16 // related to UnixConn and UnixListener are not implemented.
  17
  18 // UnixAddr represents the address of a Unix domain socket end point.
  19 type UnixAddr struct {
  20         Name string
  21         Net  string
  22 }
  23
  24 // Network returns the address's network name, "unix", "unixgram" or
  25 // "unixpacket".
  26 func (a *UnixAddr) Network() string {
  27         return a.Net
  28 }
  29
  30 func (a *UnixAddr) String() string {
  31         if a == nil {
  32                 return "<nil>"
  33         }
  34         return a.Name
  35 }
  36
  37 func (a *UnixAddr) isWildcard() bool {
  38         return a == nil || a.Name == ""
  39 }
  40
  41 func (a *UnixAddr) opAddr() Addr {
  42         if a == nil {
  43                 return nil
  44         }
  45         return a
  46 }
  47
  48 // ResolveUnixAddr returns an address of Unix domain socket end point.
  49 //
  50 // The network must be a Unix network name.
  51 //
  52 // See func Dial for a description of the network and address
  53 // parameters.
  54 func ResolveUnixAddr(network, address string) (*UnixAddr, error) {
  55         switch network {
  56         case "unix", "unixgram", "unixpacket":
  57                 return &UnixAddr{Name: address, Net: network}, nil
  58         default:
  59                 return nil, UnknownNetworkError(network)
  60         }
  61 }
  62
  63 // UnixConn is an implementation of the Conn interface for connections
  64 // to Unix domain sockets.
  65 type UnixConn struct {
  66         conn
  67 }
  68
  69 // SyscallConn returns a raw network connection.
  70 // This implements the syscall.Conn interface.
  71 func (c *UnixConn) SyscallConn() (syscall.RawConn, error) {
  72         if !c.ok() {
  73                 return nil, syscall.EINVAL
  74         }
  75         return newRawConn(c.fd)
  76 }
  77
  78 // CloseRead shuts down the reading side of the Unix domain connection.
  79 // Most callers should just use Close.
  80 func (c *UnixConn) CloseRead() error {
  81         if !c.ok() {
  82                 return syscall.EINVAL
  83         }
  84         if err := c.fd.closeRead(); err != nil {
  85                 return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
  86         }
  87         return nil
  88 }
  89
  90 // CloseWrite shuts down the writing side of the Unix domain connection.
  91 // Most callers should just use Close.
  92 func (c *UnixConn) CloseWrite() error {
  93         if !c.ok() {
  94                 return syscall.EINVAL
  95         }
  96         if err := c.fd.closeWrite(); err != nil {
  97                 return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
  98         }
  99         return nil
 100 }
 101
 102 // ReadFromUnix acts like ReadFrom but returns a UnixAddr.
 103 func (c *UnixConn) ReadFromUnix(b []byte) (int, *UnixAddr, error) {
 104         if !c.ok() {
 105                 return 0, nil, syscall.EINVAL
 106         }
 107         n, addr, err := c.readFrom(b)
 108         if err != nil {
 109                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 110         }
 111         return n, addr, err
 112 }
 113
 114 // ReadFrom implements the PacketConn ReadFrom method.
 115 func (c *UnixConn) ReadFrom(b []byte) (int, Addr, error) {
 116         if !c.ok() {
 117                 return 0, nil, syscall.EINVAL
 118         }
 119         n, addr, err := c.readFrom(b)
 120         if err != nil {
 121                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 122         }
 123         if addr == nil {
 124                 return n, nil, err
 125         }
 126         return n, addr, err
 127 }
 128
 129 // ReadMsgUnix reads a message from c, copying the payload into b and
 130 // the associated out-of-band data into oob. It returns the number of
 131 // bytes copied into b, the number of bytes copied into oob, the flags
 132 // that were set on the message and the source address of the message.
 133 //
 134 // Note that if len(b) == 0 and len(oob) > 0, this function will still
 135 // read (and discard) 1 byte from the connection.
 136 func (c *UnixConn) ReadMsgUnix(b, oob []byte) (n, oobn, flags int, addr *UnixAddr, err error) {
 137         if !c.ok() {
 138                 return 0, 0, 0, nil, syscall.EINVAL
 139         }
 140         n, oobn, flags, addr, err = c.readMsg(b, oob)
 141         if err != nil {
 142                 err = &OpError{Op: "read", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
 143         }
 144         return
 145 }
 146
 147 // WriteToUnix acts like WriteTo but takes a UnixAddr.
 148 func (c *UnixConn) WriteToUnix(b []byte, addr *UnixAddr) (int, error) {
 149         if !c.ok() {
 150                 return 0, syscall.EINVAL
 151         }
 152         n, err := c.writeTo(b, addr)
 153         if err != nil {
 154                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 155         }
 156         return n, err
 157 }
 158
 159 // WriteTo implements the PacketConn WriteTo method.
 160 func (c *UnixConn) WriteTo(b []byte, addr Addr) (int, error) {
 161         if !c.ok() {
 162                 return 0, syscall.EINVAL
 163         }
 164         a, ok := addr.(*UnixAddr)
 165         if !ok {
 166                 return 0, &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr, Err: syscall.EINVAL}
 167         }
 168         n, err := c.writeTo(b, a)
 169         if err != nil {
 170                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: a.opAddr(), Err: err}
 171         }
 172         return n, err
 173 }
 174
 175 // WriteMsgUnix writes a message to addr via c, copying the payload
 176 // from b and the associated out-of-band data from oob. It returns the
 177 // number of payload and out-of-band bytes written.
 178 //
 179 // Note that if len(b) == 0 and len(oob) > 0, this function will still
 180 // write 1 byte to the connection.
 181 func (c *UnixConn) WriteMsgUnix(b, oob []byte, addr *UnixAddr) (n, oobn int, err error) {
 182         if !c.ok() {
 183                 return 0, 0, syscall.EINVAL
 184         }
 185         n, oobn, err = c.writeMsg(b, oob, addr)
 186         if err != nil {
 187                 err = &OpError{Op: "write", Net: c.fd.net, Source: c.fd.laddr, Addr: addr.opAddr(), Err: err}
 188         }
 189         return
 190 }
 191
 192 func newUnixConn(fd *netFD) *UnixConn { return &UnixConn{conn{fd}} }
 193
 194 // DialUnix acts like Dial for Unix networks.
 195 //
 196 // The network must be a Unix network name; see func Dial for details.
 197 //
 198 // If laddr is non-nil, it is used as the local address for the
 199 // connection.
 200 func DialUnix(network string, laddr, raddr *UnixAddr) (*UnixConn, error) {
 201         switch network {
 202         case "unix", "unixgram", "unixpacket":
 203         default:
 204                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: UnknownNetworkError(network)}
 205         }
 206         sd := &sysDialer{network: network, address: raddr.String()}
 207         c, err := sd.dialUnix(context.Background(), laddr, raddr)
 208         if err != nil {
 209                 return nil, &OpError{Op: "dial", Net: network, Source: laddr.opAddr(), Addr: raddr.opAddr(), Err: err}
 210         }
 211         return c, nil
 212 }
 213
 214 // UnixListener is a Unix domain socket listener. Clients should
 215 // typically use variables of type Listener instead of assuming Unix
 216 // domain sockets.
 217 type UnixListener struct {
 218         fd         *netFD
 219         path       string
 220         unlink     bool
 221         unlinkOnce sync.Once
 222 }
 223
 224 func (ln *UnixListener) ok() bool { return ln != nil && ln.fd != nil }
 225
 226 // SyscallConn returns a raw network connection.
 227 // This implements the syscall.Conn interface.
 228 //
 229 // The returned RawConn only supports calling Control. Read and
 230 // Write return an error.
 231 func (l *UnixListener) SyscallConn() (syscall.RawConn, error) {
 232         if !l.ok() {
 233                 return nil, syscall.EINVAL
 234         }
 235         return newRawListener(l.fd)
 236 }
 237
 238 // AcceptUnix accepts the next incoming call and returns the new
 239 // connection.
 240 func (l *UnixListener) AcceptUnix() (*UnixConn, error) {
 241         if !l.ok() {
 242                 return nil, syscall.EINVAL
 243         }
 244         c, err := l.accept()
 245         if err != nil {
 246                 return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 247         }
 248         return c, nil
 249 }
 250
 251 // Accept implements the Accept method in the Listener interface.
 252 // Returned connections will be of type *UnixConn.
 253 func (l *UnixListener) Accept() (Conn, error) {
 254         if !l.ok() {
 255                 return nil, syscall.EINVAL
 256         }
 257         c, err := l.accept()
 258         if err != nil {
 259                 return nil, &OpError{Op: "accept", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 260         }
 261         return c, nil
 262 }
 263
 264 // Close stops listening on the Unix address. Already accepted
 265 // connections are not closed.
 266 func (l *UnixListener) Close() error {
 267         if !l.ok() {
 268                 return syscall.EINVAL
 269         }
 270         if err := l.close(); err != nil {
 271                 return &OpError{Op: "close", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 272         }
 273         return nil
 274 }
 275
 276 // Addr returns the listener's network address.
 277 // The Addr returned is shared by all invocations of Addr, so
 278 // do not modify it.
 279 func (l *UnixListener) Addr() Addr { return l.fd.laddr }
 280
 281 // SetDeadline sets the deadline associated with the listener.
 282 // A zero time value disables the deadline.
 283 func (l *UnixListener) SetDeadline(t time.Time) error {
 284         if !l.ok() {
 285                 return syscall.EINVAL
 286         }
 287         if err := l.fd.pfd.SetDeadline(t); err != nil {
 288                 return &OpError{Op: "set", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 289         }
 290         return nil
 291 }
 292
 293 // File returns a copy of the underlying os.File.
 294 // It is the caller's responsibility to close f when finished.
 295 // Closing l does not affect f, and closing f does not affect l.
 296 //
 297 // The returned os.File's file descriptor is different from the
 298 // connection's. Attempting to change properties of the original
 299 // using this duplicate may or may not have the desired effect.
 300 func (l *UnixListener) File() (f *os.File, err error) {
 301         if !l.ok() {
 302                 return nil, syscall.EINVAL
 303         }
 304         f, err = l.file()
 305         if err != nil {
 306                 err = &OpError{Op: "file", Net: l.fd.net, Source: nil, Addr: l.fd.laddr, Err: err}
 307         }
 308         return
 309 }
 310
 311 // ListenUnix acts like Listen for Unix networks.
 312 //
 313 // The network must be "unix" or "unixpacket".
 314 func ListenUnix(network string, laddr *UnixAddr) (*UnixListener, error) {
 315         switch network {
 316         case "unix", "unixpacket":
 317         default:
 318                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)}
 319         }
 320         if laddr == nil {
 321                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: errMissingAddress}
 322         }
 323         sl := &sysListener{network: network, address: laddr.String()}
 324         ln, err := sl.listenUnix(context.Background(), laddr)
 325         if err != nil {
 326                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
 327         }
 328         return ln, nil
 329 }
 330
 331 // ListenUnixgram acts like ListenPacket for Unix networks.
 332 //
 333 // The network must be "unixgram".
 334 func ListenUnixgram(network string, laddr *UnixAddr) (*UnixConn, error) {
 335         switch network {
 336         case "unixgram":
 337         default:
 338                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: UnknownNetworkError(network)}
 339         }
 340         if laddr == nil {
 341                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: nil, Err: errMissingAddress}
 342         }
 343         sl := &sysListener{network: network, address: laddr.String()}
 344         c, err := sl.listenUnixgram(context.Background(), laddr)
 345         if err != nil {
 346                 return nil, &OpError{Op: "listen", Net: network, Source: nil, Addr: laddr.opAddr(), Err: err}
 347         }
 348         return c, nil
 349 }