125 lines
2.8 KiB
Go
125 lines
2.8 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build plan9
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package safesocket
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import (
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"fmt"
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"net"
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"os"
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"syscall"
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"time"
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"golang.org/x/sys/plan9"
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)
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// Plan 9's devsrv srv(3) is a server registry and
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// it is conventionally bound to "/srv" in the default
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// namespace. It is "a one level directory for holding
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// already open channels to services". Post one end of
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// a pipe to "/srv/tailscale.sock" and use the other
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// end for communication with a requestor. Plan 9 pipes
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// are bidirectional.
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type plan9SrvAddr string
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func (sl plan9SrvAddr) Network() string {
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return "/srv"
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}
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func (sl plan9SrvAddr) String() string {
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return string(sl)
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}
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// There is no net.FileListener for Plan 9 at this time
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type plan9SrvListener struct {
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name string
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srvf *os.File
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file *os.File
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}
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func (sl *plan9SrvListener) Accept() (net.Conn, error) {
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// sl.file is the server end of the pipe that's
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// connected to /srv/tailscale.sock
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return plan9FileConn{name: sl.name, file: sl.file}, nil
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}
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func (sl *plan9SrvListener) Close() error {
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sl.file.Close()
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return sl.srvf.Close()
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}
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func (sl *plan9SrvListener) Addr() net.Addr {
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return plan9SrvAddr(sl.name)
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}
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type plan9FileConn struct {
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name string
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file *os.File
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}
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func (fc plan9FileConn) Read(b []byte) (n int, err error) {
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return fc.file.Read(b)
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}
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func (fc plan9FileConn) Write(b []byte) (n int, err error) {
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return fc.file.Write(b)
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}
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func (fc plan9FileConn) Close() error {
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return fc.file.Close()
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}
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func (fc plan9FileConn) LocalAddr() net.Addr {
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return plan9SrvAddr(fc.name)
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}
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func (fc plan9FileConn) RemoteAddr() net.Addr {
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return plan9SrvAddr(fc.name)
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}
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func (fc plan9FileConn) SetDeadline(t time.Time) error {
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return syscall.EPLAN9
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}
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func (fc plan9FileConn) SetReadDeadline(t time.Time) error {
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return syscall.EPLAN9
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}
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func (fc plan9FileConn) SetWriteDeadline(t time.Time) error {
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return syscall.EPLAN9
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}
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func connect(path string) (net.Conn, error) {
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f, err := os.OpenFile(path, os.O_RDWR, 0666)
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if err != nil {
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return nil, err
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}
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return plan9FileConn{name: path, file: f}, nil
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}
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// Create an entry in /srv, open a pipe, write the
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// client end to the entry and return the server
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// end of the pipe to the caller. When the server
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// end of the pipe is closed, /srv name associated
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// with it will be removed (controlled by ORCLOSE flag)
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func listen(path string) (net.Listener, error) {
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const O_RCLOSE = 64 // remove on close; should be in plan9 package
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var pip [2]int
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err := plan9.Pipe(pip[:])
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if err != nil {
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return nil, err
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}
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defer plan9.Close(pip[1])
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srvfd, err := plan9.Create(path, plan9.O_WRONLY|plan9.O_CLOEXEC|O_RCLOSE, 0600)
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if err != nil {
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return nil, err
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}
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srv := os.NewFile(uintptr(srvfd), path)
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_, err = fmt.Fprintf(srv, "%d", pip[1])
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if err != nil {
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return nil, err
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}
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return &plan9SrvListener{name: path, srvf: srv, file: os.NewFile(uintptr(pip[0]), path)}, nil
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}
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