Source file src/pkg/net/sock.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	// +build darwin freebsd linux netbsd openbsd windows
     6	
     7	// Sockets
     8	
     9	package net
    10	
    11	import (
    12		"io"
    13		"syscall"
    14	)
    15	
    16	var listenerBacklog = maxListenerBacklog()
    17	
    18	// Generic socket creation.
    19	func socket(net string, f, t, p int, ipv6only bool, la, ra syscall.Sockaddr, toAddr func(syscall.Sockaddr) Addr) (fd *netFD, err error) {
    20		// See ../syscall/exec.go for description of ForkLock.
    21		syscall.ForkLock.RLock()
    22		s, err := syscall.Socket(f, t, p)
    23		if err != nil {
    24			syscall.ForkLock.RUnlock()
    25			return nil, err
    26		}
    27		syscall.CloseOnExec(s)
    28		syscall.ForkLock.RUnlock()
    29	
    30		err = setDefaultSockopts(s, f, t, ipv6only)
    31		if err != nil {
    32			closesocket(s)
    33			return nil, err
    34		}
    35	
    36		var bla syscall.Sockaddr
    37		if la != nil {
    38			bla, err = listenerSockaddr(s, f, la, toAddr)
    39			if err != nil {
    40				closesocket(s)
    41				return nil, err
    42			}
    43			err = syscall.Bind(s, bla)
    44			if err != nil {
    45				closesocket(s)
    46				return nil, err
    47			}
    48		}
    49	
    50		if fd, err = newFD(s, f, t, net); err != nil {
    51			closesocket(s)
    52			return nil, err
    53		}
    54	
    55		if ra != nil {
    56			if err = fd.connect(ra); err != nil {
    57				closesocket(s)
    58				fd.Close()
    59				return nil, err
    60			}
    61			fd.isConnected = true
    62		}
    63	
    64		sa, _ := syscall.Getsockname(s)
    65		var laddr Addr
    66		if la != nil && bla != la {
    67			laddr = toAddr(la)
    68		} else {
    69			laddr = toAddr(sa)
    70		}
    71		sa, _ = syscall.Getpeername(s)
    72		raddr := toAddr(sa)
    73	
    74		fd.setAddr(laddr, raddr)
    75		return fd, nil
    76	}
    77	
    78	type writerOnly struct {
    79		io.Writer
    80	}
    81	
    82	// Fallback implementation of io.ReaderFrom's ReadFrom, when sendfile isn't
    83	// applicable.
    84	func genericReadFrom(w io.Writer, r io.Reader) (n int64, err error) {
    85		// Use wrapper to hide existing r.ReadFrom from io.Copy.
    86		return io.Copy(writerOnly{w}, r)
    87	}