file_plan9.mx raw

   1  // Copyright 2011 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  	"errors"
   9  	"io"
  10  	"os"
  11  	"syscall"
  12  )
  13  
  14  func (fd *netFD) status(ln int) (string, error) {
  15  	if !fd.ok() {
  16  		return "", syscall.EINVAL
  17  	}
  18  
  19  	status, err := os.Open(fd.dir + "/status")
  20  	if err != nil {
  21  		return "", err
  22  	}
  23  	defer status.Close()
  24  	buf := []byte{:ln}
  25  	n, err := io.ReadFull(status, buf[:])
  26  	if err != nil {
  27  		return "", err
  28  	}
  29  	return string(buf[:n]), nil
  30  }
  31  
  32  func newFileFD(f *os.File) (net *netFD, err error) {
  33  	var ctl *os.File
  34  	close := func(fd int) {
  35  		if err != nil {
  36  			syscall.Close(fd)
  37  		}
  38  	}
  39  
  40  	path, err := syscall.Fd2path(int(f.Fd()))
  41  	if err != nil {
  42  		return nil, os.NewSyscallError("fd2path", err)
  43  	}
  44  	comp := splitAtBytes(path, "/")
  45  	n := len(comp)
  46  	if n < 3 || comp[0][0:3] != "net" {
  47  		return nil, syscall.EPLAN9
  48  	}
  49  
  50  	name := comp[2]
  51  	switch file := comp[n-1]; file {
  52  	case "ctl", "clone":
  53  		fd, err := syscall.Dup(int(f.Fd()), -1)
  54  		if err != nil {
  55  			return nil, os.NewSyscallError("dup", err)
  56  		}
  57  		defer close(fd)
  58  
  59  		dir := netdir + "/" + comp[n-2]
  60  		ctl = os.NewFile(uintptr(fd), dir+"/"+file)
  61  		ctl.Seek(0, io.SeekStart)
  62  		var buf [16]byte
  63  		n, err := ctl.Read(buf[:])
  64  		if err != nil {
  65  			return nil, err
  66  		}
  67  		name = string(buf[:n])
  68  	default:
  69  		if len(comp) < 4 {
  70  			return nil, errors.New("could not find control file for connection")
  71  		}
  72  		dir := netdir + "/" + comp[1] + "/" + name
  73  		ctl, err = os.OpenFile(dir+"/ctl", os.O_RDWR, 0)
  74  		if err != nil {
  75  			return nil, err
  76  		}
  77  		defer close(int(ctl.Fd()))
  78  	}
  79  	dir := netdir + "/" + comp[1] + "/" + name
  80  	laddr, err := readPlan9Addr(comp[1], dir+"/local")
  81  	if err != nil {
  82  		return nil, err
  83  	}
  84  	return newFD(comp[1], name, nil, ctl, nil, laddr, nil)
  85  }
  86  
  87  func fileConn(f *os.File) (Conn, error) {
  88  	fd, err := newFileFD(f)
  89  	if err != nil {
  90  		return nil, err
  91  	}
  92  	if !fd.ok() {
  93  		return nil, syscall.EINVAL
  94  	}
  95  
  96  	fd.data, err = os.OpenFile(fd.dir+"/data", os.O_RDWR, 0)
  97  	if err != nil {
  98  		return nil, err
  99  	}
 100  
 101  	switch fd.laddr.(type) {
 102  	case *TCPAddr:
 103  		return newTCPConn(fd, defaultTCPKeepAliveIdle, KeepAliveConfig{}, testPreHookSetKeepAlive, testHookSetKeepAlive), nil
 104  	case *UDPAddr:
 105  		return newUDPConn(fd), nil
 106  	}
 107  	return nil, syscall.EPLAN9
 108  }
 109  
 110  func fileListener(f *os.File) (Listener, error) {
 111  	fd, err := newFileFD(f)
 112  	if err != nil {
 113  		return nil, err
 114  	}
 115  	switch fd.laddr.(type) {
 116  	case *TCPAddr:
 117  	default:
 118  		return nil, syscall.EPLAN9
 119  	}
 120  
 121  	// check that file corresponds to a listener
 122  	s, err := fd.status(len("Listen"))
 123  	if err != nil {
 124  		return nil, err
 125  	}
 126  	if s != "Listen" {
 127  		return nil, errors.New("file does not represent a listener")
 128  	}
 129  
 130  	return &TCPListener{fd: fd}, nil
 131  }
 132  
 133  func filePacketConn(f *os.File) (PacketConn, error) {
 134  	return nil, syscall.EPLAN9
 135  }
 136