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
5package net
6
7import (
8	"errors"
9	"io"
10	"os"
11	"syscall"
12)
13
14func (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 := make([]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
32func 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
87func 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), nil
104	case *UDPAddr:
105		return newUDPConn(fd), nil
106	}
107	return nil, syscall.EPLAN9
108}
109
110func 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}, nil
131}
132
133func filePacketConn(f *os.File) (PacketConn, error) {
134	return nil, syscall.EPLAN9
135}
136