package main import ( "errors" "fmt" "golang.org/x/sys/unix" "net" "os" "path" ) const ( ipcErrorIO = -int64(unix.EIO) ipcErrorProtocol = -int64(unix.EPROTO) ipcErrorInvalid = -int64(unix.EINVAL) ipcErrorPortInUse = -int64(unix.EADDRINUSE) socketDirectory = "/var/run/wireguard" socketName = "%s.sock" ) type UAPIListener struct { listener net.Listener // unix socket listener connNew chan net.Conn connErr chan error inotifyFd int } func (l *UAPIListener) Accept() (net.Conn, error) { for { select { case conn := <-l.connNew: return conn, nil case err := <-l.connErr: return nil, err } } } func (l *UAPIListener) Close() error { err1 := unix.Close(l.inotifyFd) err2 := l.listener.Close() if err1 != nil { return err1 } return err2 } func (l *UAPIListener) Addr() net.Addr { return nil } func UAPIListen(name string, file *os.File) (net.Listener, error) { // wrap file in listener listener, err := net.FileListener(file) if err != nil { return nil, err } uapi := &UAPIListener{ listener: listener, connNew: make(chan net.Conn, 1), connErr: make(chan error, 1), } // watch for deletion of socket socketPath := path.Join( socketDirectory, fmt.Sprintf(socketName, name), ) uapi.inotifyFd, err = unix.InotifyInit() if err != nil { return nil, err } _, err = unix.InotifyAddWatch( uapi.inotifyFd, socketPath, unix.IN_ATTRIB| unix.IN_DELETE| unix.IN_DELETE_SELF, ) if err != nil { return nil, err } go func(l *UAPIListener) { var buff [4096]byte for { // start with lstat to avoid race condition if _, err := os.Lstat(socketPath); os.IsNotExist(err) { l.connErr <- err return } unix.Read(uapi.inotifyFd, buff[:]) } }(uapi) // watch for new connections go func(l *UAPIListener) { for { conn, err := l.listener.Accept() if err != nil { l.connErr <- err break } l.connNew <- conn } }(uapi) return uapi, nil } func UAPIOpen(name string) (*os.File, error) { // check if path exist err := os.MkdirAll(socketDirectory, 0600) if err != nil && !os.IsExist(err) { return nil, err } // open UNIX socket socketPath := path.Join( socketDirectory, fmt.Sprintf(socketName, name), ) addr, err := net.ResolveUnixAddr("unix", socketPath) if err != nil { return nil, err } listener, err := func() (*net.UnixListener, error) { // initial connection attempt listener, err := net.ListenUnix("unix", addr) if err == nil { return listener, nil } // check if socket already active _, err = net.Dial("unix", socketPath) if err == nil { return nil, errors.New("unix socket in use") } // cleanup & attempt again err = os.Remove(socketPath) if err != nil { return nil, err } return net.ListenUnix("unix", addr) }() if err != nil { return nil, err } return listener.File() }