1 files changed, 157 insertions, 0 deletions
diff --git a/src/net/file_plan9.go b/src/net/file_plan9.go
new file mode 100644
index 000000000..068f0881d
--- /dev/null
+++ b/src/net/file_plan9.go
@@ -0,0 +1,157 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package net
+
+import (
+	"errors"
+	"io"
+	"os"
+	"syscall"
+)
+
+func (fd *netFD) status(ln int) (string, error) {
+	if !fd.ok() {
+		return "", syscall.EINVAL
+	}
+
+	status, err := os.Open(fd.dir + "/status")
+	if err != nil {
+		return "", err
+	}
+	defer status.Close()
+	buf := make([]byte, ln)
+	n, err := io.ReadFull(status, buf[:])
+	if err != nil {
+		return "", err
+	}
+	return string(buf[:n]), nil
+}
+
+func newFileFD(f *os.File) (net *netFD, err error) {
+	var ctl *os.File
+	close := func(fd int) {
+		if err != nil {
+			syscall.Close(fd)
+		}
+	}
+
+	path, err := syscall.Fd2path(int(f.Fd()))
+	if err != nil {
+		return nil, os.NewSyscallError("fd2path", err)
+	}
+	comp := splitAtBytes(path, "/")
+	n := len(comp)
+	if n < 3 || comp[0][0:3] != "net" {
+		return nil, syscall.EPLAN9
+	}
+
+	name := comp[2]
+	switch file := comp[n-1]; file {
+	case "ctl", "clone":
+		syscall.ForkLock.RLock()
+		fd, err := syscall.Dup(int(f.Fd()), -1)
+		syscall.ForkLock.RUnlock()
+		if err != nil {
+			return nil, os.NewSyscallError("dup", err)
+		}
+		defer close(fd)
+
+		dir := netdir + "/" + comp[n-2]
+		ctl = os.NewFile(uintptr(fd), dir+"/"+file)
+		ctl.Seek(0, 0)
+		var buf [16]byte
+		n, err := ctl.Read(buf[:])
+		if err != nil {
+			return nil, err
+		}
+		name = string(buf[:n])
+	default:
+		if len(comp) < 4 {
+			return nil, errors.New("could not find control file for connection")
+		}
+		dir := netdir + "/" + comp[1] + "/" + name
+		ctl, err = os.OpenFile(dir+"/ctl", os.O_RDWR, 0)
+		if err != nil {
+			return nil, err
+		}
+		defer close(int(ctl.Fd()))
+	}
+	dir := netdir + "/" + comp[1] + "/" + name
+	laddr, err := readPlan9Addr(comp[1], dir+"/local")
+	if err != nil {
+		return nil, err
+	}
+	return newFD(comp[1], name, ctl, nil, laddr, nil)
+}
+
+func newFileConn(f *os.File) (c Conn, err error) {
+	fd, err := newFileFD(f)
+	if err != nil {
+		return nil, err
+	}
+	if !fd.ok() {
+		return nil, syscall.EINVAL
+	}
+
+	fd.data, err = os.OpenFile(fd.dir+"/data", os.O_RDWR, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	switch fd.laddr.(type) {
+	case *TCPAddr:
+		return newTCPConn(fd), nil
+	case *UDPAddr:
+		return newUDPConn(fd), nil
+	}
+	return nil, syscall.EPLAN9
+}
+
+func newFileListener(f *os.File) (l Listener, err error) {
+	fd, err := newFileFD(f)
+	if err != nil {
+		return nil, err
+	}
+	switch fd.laddr.(type) {
+	case *TCPAddr:
+	default:
+		return nil, syscall.EPLAN9
+	}
+
+	// check that file corresponds to a listener
+	s, err := fd.status(len("Listen"))
+	if err != nil {
+		return nil, err
+	}
+	if s != "Listen" {
+		return nil, errors.New("file does not represent a listener")
+	}
+
+	return &TCPListener{fd}, nil
+}
+
+// FileConn returns a copy of the network connection corresponding to
+// the open file f.  It is the caller's responsibility to close f when
+// finished.  Closing c does not affect f, and closing f does not
+// affect c.
+func FileConn(f *os.File) (c Conn, err error) {
+	return newFileConn(f)
+}
+
+// FileListener returns a copy of the network listener corresponding
+// to the open file f.  It is the caller's responsibility to close l
+// when finished.  Closing l does not affect f, and closing f does not
+// affect l.
+func FileListener(f *os.File) (l Listener, err error) {
+	return newFileListener(f)
+}
+
+// FilePacketConn returns a copy of the packet network connection
+// corresponding to the open file f.  It is the caller's
+// responsibility to close f when finished.  Closing c does not affect
+// f, and closing f does not affect c.
+func FilePacketConn(f *os.File) (c PacketConn, err error) {
+	return nil, syscall.EPLAN9
+}