drivers.c

来自「gpsd, a popular GPS daemon.」· C语言 代码 · 共 927 行 · 第 1/3 页

/* $Id: drivers.c 4663 2008-01-20 23:35:32Z garyemiller $ */
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <stdarg.h>

#include "gpsd_config.h"
#include "gpsd.h"

extern struct gps_type_t zodiac_binary;
extern struct gps_type_t ubx_binary;

ssize_t generic_get(struct gps_device_t *session)
{
    return packet_get(session->gpsdata.gps_fd, &session->packet);
}

#if defined(NMEA_ENABLE) || defined(SIRF_ENABLE) || defined(EVERMORE_ENABLE)  || defined(ITRAX_ENABLE)  || defined(NAVCOM_ENABLE)
ssize_t pass_rtcm(struct gps_device_t *session, char *buf, size_t rtcmbytes)
/* most GPSes take their RTCM corrections straight up */
{
    return gpsd_write(session, buf, rtcmbytes);
}
#endif

#ifdef NMEA_ENABLE
/**************************************************************************
 *
 * Generic driver -- straight NMEA 0183
 *
 **************************************************************************/

gps_mask_t nmea_parse_input(struct gps_device_t *session)
{
    if (session->packet.type == COMMENT_PACKET) {
	return 0;
    } else if (session->packet.type == SIRF_PACKET) {
	gpsd_report(LOG_WARN, "SiRF packet seen when NMEA expected.\n");
#ifdef SIRF_ENABLE
	(void)gpsd_switch_driver(session, "SiRF binary");
	return sirf_parse(session, session->packet.outbuffer, session->packet.outbuflen);
#else
	return 0;
#endif /* SIRF_ENABLE */
    } else if (session->packet.type == EVERMORE_PACKET) {
	gpsd_report(LOG_WARN, "EverMore packet seen when NMEA expected.\n");
#ifdef EVERMORE_ENABLE
	(void)gpsd_switch_driver(session, "EverMore binary");
	return evermore_parse(session, session->packet.outbuffer, session->packet.outbuflen);
#else
	return 0;
#endif /* EVERMORE_ENABLE */
    } else if (session->packet.type == NAVCOM_PACKET) {
  gpsd_report(LOG_WARN, "Navcom packet seen when NMEA expected.\n");
#ifdef NAVCOM_ENABLE
	(void)gpsd_switch_driver(session, "Navcom binary");
	return navcom_parse(session, session->packet.outbuffer, session->packet.outbuflen);
#else
	return 0;
#endif /* NAVCOM_ENABLE */
} else if (session->packet.type == GARMIN_PACKET) {
	gpsd_report(LOG_WARN, "Garmin packet seen when NMEA expected.\n");
#ifdef GARMIN_ENABLE
	/* we might never see a trigger, have this as a backstop */
	(void)gpsd_switch_driver(session, "Garmin Serial binary");
	return garmin_ser_parse(session);
#else
	return 0;
#endif /* GARMIN_ENABLE */
    } else if (session->packet.type == NMEA_PACKET) {
	gps_mask_t st = 0;
#ifdef GARMINTXT_ENABLE
	if (session->packet.outbuflen >= 56) {
		if ((char) *session->packet.outbuffer == '@') {
		/* Garmin Simple Text packet received; it starts with '@' is terminated with \r\n and has length 57 bytes */
			(void)gpsd_switch_driver(session, "Garmin Simple Text");
			return garmintxt_parse(session);
		}
	}
#endif /* GARMINTXT_ENABLE */
	gpsd_report(LOG_IO, "<= GPS: %s", session->packet.outbuffer);
	if ((st=nmea_parse((char *)session->packet.outbuffer, session))==0) {
#ifdef NON_NMEA_ENABLE
	    struct gps_type_t **dp;

	    /* maybe this is a trigger string for a driver we know about? */
	    for (dp = gpsd_drivers; *dp; dp++) {
		char	*trigger = (*dp)->trigger;

		if (trigger!=NULL && strncmp((char *)session->packet.outbuffer, trigger, strlen(trigger))==0 && isatty(session->gpsdata.gps_fd)!=0) {
		    gpsd_report(LOG_PROG, "found %s.\n", trigger);
		    (void)gpsd_switch_driver(session, (*dp)->type_name);
		    return 1;
		}
	    }
#endif /* NON_NMEA_ENABLE */
	    gpsd_report(LOG_WARN, "unknown sentence: \"%s\"\n", session->packet.outbuffer);
	}
#ifdef NMEADISC
	if (session->ldisc == 0) {
	    uid_t old;
	    int ldisc = NMEADISC;

#ifdef TIOCSTSTAMP
	    struct tstamps tstamps;
#ifdef PPS_ON_CTS
	    tstamps.ts_set |= TIOCM_CTS;
#else /*!PPS_ON_CTS */
	    tstamps.ts_set |= TIOCM_CAR;
#endif /* PPS_ON_CTS */
	    tstamps.ts_clr = 0;

	    old = geteuid();
	    if (seteuid(0) == -1)
		gpsd_report(LOG_WARN, "can't seteuid(0) - %s", strerror(errno));
	    else
		gpsd_report(LOG_WARN, "seteuid(0) to enable timestamping\n");
	    if (ioctl(session->gpsdata.gps_fd, TIOCSTSTAMP, &tstamps) < 0)
		gpsd_report(LOG_WARN, "can't set kernel timestamping: %s\n",
		    strerror(errno));
	    else
		gpsd_report(LOG_WARN, "activated kernel timestamping\n");
#endif /* TIOCSTSTAMP */
	    if (ioctl(session->gpsdata.gps_fd, TIOCSETD, &ldisc) == -1)
		gpsd_report(LOG_WARN, "can't set nmea discipline: %s\n",
		    strerror(errno));
	    else
		gpsd_report(LOG_WARN, "activated nmea discipline\n");
	/* this is a flag that shows if we've tried the setup */
	session->ldisc = NMEADISC;

	if (old){
	    gpsd_report(LOG_WARN, "giving up euid 0\n");
	    (void)seteuid(old);
	}
	gpsd_report(LOG_WARN, "running with effective user ID %d\n", geteuid());
	}
#endif /*NMEADISC */
#ifdef NTPSHM_ENABLE
	/* this magic number is derived from observation */
	if (session->context->enable_ntpshm &&
	    (st & TIME_SET) != 0 &&
	    (session->gpsdata.fix.time!=session->last_fixtime)) {
	    (void)ntpshm_put(session, session->gpsdata.fix.time);
	    session->last_fixtime = session->gpsdata.fix.time;
	}
#endif /* NTPSHM_ENABLE */
	return st;
    } else
	return 0;
}

static void nmea_probe_subtype(struct gps_device_t *session, unsigned int seq)
{
    /*
     * The reason for splitting these probes up by packet sequence
     * number, interleaving them with the first few packet receives,
     * is because many generic-NMEA devices get confused if you send
     * too much at them in one go.
     *
     * A fast response to an early probe will change drivers so the
     * later ones won't be sent at all.  Thus, for best overall
     * performance, order these to probe for the most popular types
     * soonest.
     *
     * Note: don't make the trigger strings identical to the probe,
     * because some NMEA devices (notably SiRFs) will just echo
     * unknown strings right back at you. A useful dodge is to append
     * a comma to the trigger, because that won't be in the response
     * unless there is actual following data.
     */
    switch (seq) {
#ifdef SIRF_ENABLE
    case 0:
	/*
	 * We used to try to probe for SiRF by issuing "$PSRF105,1"
	 * and expecting "$Ack Input105.".  But it turns out this
	 * only works for SiRF-IIs; SiRF-I and SiRF-III don't respond.
	 * Thus the only reliable probe is to try to flip the SiRF into
	 * binary mode, cluing in the library to revert it on close.
	 */
	(void)nmea_send(session->gpsdata.gps_fd,
			"$PSRF100,0,%d,%d,%d,0",
			session->gpsdata.baudrate,
			9-session->gpsdata.stopbits,
			session->gpsdata.stopbits);
	session->back_to_nmea = true;
	break;
#endif /* SIRF_ENABLE */
#ifdef NMEA_ENABLE
    case 1:
	/* probe for Garmin serial GPS -- expect $PGRMC followed by data*/
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMCE");
	break;
    case 2:
	/* probe for the FV-18 -- expect $PFEC,GPint followed by data */
	(void)nmea_send(session->gpsdata.gps_fd, "$PFEC,GPint");
	break;
#endif /* NMEA_ENABLE */
#ifdef EVERMORE_ENABLE
    case 3:
	/* Enable checksum and GGA(1s), GLL(0s), GSA(1s), GSV(1s), RMC(1s), VTG(0s), PEMT101(1s) */
	/* EverMore will reply with: \x10\x02\x04\x38\x8E\xC6\x10\x03 */
	(void)gpsd_write(session,
	    "\x10\x02\x12\x8E\x7F\x01\x01\x00\x01\x01\x01\x00\x01\x00\x00\x00\x00\x00\x00\x13\x10\x03", 22);
	break;
#endif /* EVERMORE_ENABLE */
#ifdef ITRAX_ENABLE
    case 4:
	/* probe for iTrax, looking for "$PFST,OK" */
	(void)nmea_send(session->gpsdata.gps_fd, "$PFST");
	break;
#endif /* ITRAX_ENABLE */
#ifdef GPSCLOCK_ENABLE
    case 5:
	/* probe for Furuno Electric GH-79L4-N (GPSClock) */
	(void)nmea_send(session->gpsdata.gps_fd, "$PFEC,GPsrq");
	break;
#endif /* GPSCLOCK_ENABLE */
#ifdef ASHTECH_ENABLE
    case 6:
	/* probe for Ashtech -- expect $PASHR */
	(void)nmea_send(session->gpsdata.gps_fd, "$PASHQ,RID");
	break;
#endif /* ASHTECH_ENABLE */
    default:
	break;
    }
}

static struct gps_type_t nmea = {
    .type_name      = "Generic NMEA",	/* full name of type */
    .trigger	    = NULL,		/* it's the default */
    .channels       = 12,		/* consumer-grade GPS */
    .probe_wakeup   = NULL,		/* no wakeup to be done before hunt */
    .probe_detect   = NULL,		/* no probe */
    .probe_subtype  = nmea_probe_subtype, /* probe for special types */
#ifdef ALLOW_RECONFIGURE
    .configurator   = NULL,		/* enable what we need */
#endif /* ALLOW_RECONFIGURE */
    .get_packet     = generic_get,	/* use generic packet getter */
    .parse_packet   = nmea_parse_input,	/* how to interpret a packet */
    .rtcm_writer    = pass_rtcm,	/* write RTCM data straight */
    .speed_switcher = NULL,		/* no speed switcher */
    .mode_switcher  = NULL,		/* no mode switcher */
    .rate_switcher  = NULL,		/* no sample-rate switcher */
    .cycle_chars    = -1,		/* not relevant, no rate switch */
#ifdef ALLOW_RECONFIGURE
    .revert	    = NULL,		/* no setting-reversion method */
#endif /* ALLOW_RECONFIGURE */
    .wrapup	    = NULL,		/* no wrapup */
    .cycle	    = 1,		/* updates every second */
};

#if defined(GARMIN_ENABLE) && defined(NMEA_ENABLE)
/**************************************************************************
 *
 * Garmin NMEA
 *
 **************************************************************************/

#ifdef ALLOW_RECONFIGURE
static void garmin_nmea_configurator(struct gps_device_t *session, unsigned int seq)
{
    /*
     * Receivers like the Garmin GPS-10 don't handle having having a lot of
     * probes shoved at them very well.
     */
    switch (seq) {
    case 0:
	/* reset some config, AutoFix, WGS84, PPS 
	 * Set the PPS pulse length to 40ms which leaves the Garmin 18-5hz 
         * with a 160ms low state.
         * NOTE: new PPS only takes effect after next power cycle
         */
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMC,A,,100,,,,,,A,,1,2,1,30");
	break;
    case 1:
	/* once a sec, no averaging, NMEA 2.3, WAAS */
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMC1,1,1,1,,,,2,W,N");
	break;
    case 2:
	/* get some more config info */
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMC1E");
	break;
    case 3:
	/* turn off all output except GGA */
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMO,,2");
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMO,GPGGA,1");
	break;
    case 4:
	/* enable GPGGA, GPGSA, GPGSV, GPRMC on Garmin serial GPS */
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMO,GPGSA,1");
	break;
    case 5:
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMO,GPGSV,1");
	break;
    case 6:
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMO,GPRMC,1");
	break;
    case 7:
	(void)nmea_send(session->gpsdata.gps_fd, "$PGRMO,PGRME,1");
	break;