package modules import ( "fmt" "io" "time" "github.com/bettercap/bettercap/log" "github.com/bettercap/bettercap/session" "github.com/adrianmo/go-nmea" "github.com/tarm/serial" "github.com/evilsocket/islazy/str" ) type GPS struct { session.SessionModule serialPort string baudRate int serial *serial.Port } func NewGPS(s *session.Session) *GPS { gps := &GPS{ SessionModule: session.NewSessionModule("http.server", s), serialPort: "/dev/ttyUSB0", baudRate: 19200, } gps.AddParam(session.NewStringParameter("gps.device", gps.serialPort, "", "Serial device of the GPS hardware.")) gps.AddParam(session.NewIntParameter("gps.baudrate", fmt.Sprintf("%d", gps.baudRate), "Baud rate of the GPS serial device.")) gps.AddHandler(session.NewModuleHandler("gps on", "", "Start acquiring from the GPS hardware.", func(args []string) error { return gps.Start() })) gps.AddHandler(session.NewModuleHandler("gps off", "", "Stop acquiring from the GPS hardware.", func(args []string) error { return gps.Stop() })) gps.AddHandler(session.NewModuleHandler("gps.show", "", "Show the last coordinates returned by the GPS hardware.", func(args []string) error { return gps.Show() })) return gps } func (gps *GPS) Name() string { return "gps" } func (gps *GPS) Description() string { return "A module talking with GPS hardware on a serial interface." } func (gps *GPS) Author() string { return "Simone Margaritelli " } func (gps *GPS) Configure() (err error) { if gps.Running() { return session.ErrAlreadyStarted } else if err, gps.serialPort = gps.StringParam("gps.device"); err != nil { return err } else if err, gps.baudRate = gps.IntParam("gps.baudrate"); err != nil { return err } gps.serial, err = serial.OpenPort(&serial.Config{ Name: gps.serialPort, Baud: gps.baudRate, ReadTimeout: time.Second * 1, }) return } func (gps *GPS) readLine() (line string, err error) { var n int b := make([]byte, 1) for { if n, err = gps.serial.Read(b); err != nil { return } else if n == 1 { if b[0] == '\n' { return str.Trim(line), nil } else { line += string(b[0]) } } } } func (gps *GPS) Show() error { fmt.Printf("latitude:%f longitude:%f quality:%s satellites:%d altitude:%f\n", gps.Session.GPS.Latitude, gps.Session.GPS.Longitude, gps.Session.GPS.FixQuality, gps.Session.GPS.NumSatellites, gps.Session.GPS.Altitude) gps.Session.Refresh() return nil } func (gps *GPS) Start() error { if err := gps.Configure(); err != nil { return err } return gps.SetRunning(true, func() { defer gps.serial.Close() for gps.Running() { if line, err := gps.readLine(); err == nil { if s, err := nmea.Parse(line); err == nil { // http://aprs.gids.nl/nmea/#gga if m, ok := s.(nmea.GNGGA); ok { gps.Session.GPS = m } } else { log.Debug("Error parsing line '%s': %s", line, err) } } else if err != io.EOF { log.Warning("Error while reading serial port: %s", err) } } }) } func (gps *GPS) Stop() error { return gps.SetRunning(false, func() { // let the read fail and exit gps.serial.Close() }) }