path: root/libgps.c

/* $Id$ */
/* libgps.c -- client interface library for the gpsd daemon */
#include <sys/time.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdarg.h>
#ifndef S_SPLINT_S
#include <pthread.h>	/* pacifies OpenBSD's compiler */
#endif
#include <math.h>

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

#ifdef HAVE_SETLOCALE
#include <locale.h>
#endif

#ifdef S_SPLINT_S
extern char *strtok_r(char *, const char *, char **);
#endif /* S_SPLINT_S */

/* convert double degrees to a static string and return a pointer to it
 *
 * deg_str_type:
 *   	deg_dd     : return DD.dddddd
 *      deg_ddmm   : return DD MM.mmmm'
 *      deg_ddmmss : return DD MM' SS.sss"
 *
 */
/*@observer@*/char *deg_to_str( enum deg_str_type type,  double f) 
{
    static char str[40];
    int dsec, sec, deg, min;
    long frac_deg;
    double fdsec, fsec, fdeg, fmin;

    if ( f < 0 || f > 360 ) {
	(void)strlcpy( str, "nan", 40);
	return str;
    }

    fmin = modf( f, &fdeg);
    deg = (int)fdeg;
    frac_deg = (long)(fmin * 1000000);

    if ( deg_dd == type ) {
	/* DD.dddddd */
	(void)snprintf(str, sizeof(str), "%3d.%06ld", deg,frac_deg);
	return str;
    }
    fsec = modf( fmin * 60, &fmin);
    min = (int)fmin;
    sec = (int)(fsec * 10000.0);

    if ( deg_ddmm == type ) {
	/* DD MM.mmmm */
	(void)snprintf(str,sizeof(str), "%3d %02d.%04d'", deg,min,sec);
	return str;
    }
    /* else DD MM SS.sss */
    fdsec = modf( fsec * 60, &fsec);
    sec = (int)fsec;
    dsec = (int)(fdsec * 1000.0);
    (void)snprintf(str,sizeof(str), "%3d %02d' %02d.%03d\"", deg,min,sec,dsec);

    return str;
}

/* 
 * check the environment to determine proper GPS units
 *
 * clients should only call this if no user preference is specified on 
 * the command line or via X resources.
 *
 * return imperial    - Use miles/feet
 *        nautical    - Use knots/feet
 *        metric      - Use km/meters
 *        unspecified - use compiled default
 * 
 * In order check these environment vars:
 *    GPSD_UNITS one of: 
 *            	imperial   = miles/feet
 *              nautical   = knots/feet
 *              metric     = km/meters
 *    LC_MEASUREMENT
 *		en_US      = miles/feet
 *              C          = miles/feet
 *              POSIX      = miles/feet
 *              [other]    = km/meters
 *    LANG
 *		en_US      = miles/feet
 *              C          = miles/feet
 *              POSIX      = miles/feet
 *              [other]    = km/meters
 *
 * if none found then return compiled in default
 */
enum unit gpsd_units(void)
{
	char *envu = NULL;

#ifdef HAVE_SETLOCALE
	(void)setlocale(LC_NUMERIC, "C");
#endif
  	if ((envu = getenv("GPSD_UNITS")) != NULL && *envu != '\0') {
		if (0 == strcasecmp(envu, "imperial")) {
			return imperial;
		}
		if (0 == strcasecmp(envu, "nautical")) {
			return nautical;
		}
		if (0 == strcasecmp(envu, "metric")) {
			return metric;
		}
		/* unrecognized, ignore it */
	}
 	if (((envu = getenv("LC_MEASUREMENT")) != NULL && *envu != '\0') 
 	    || ((envu = getenv("LANG")) != NULL && *envu != '\0')) {
		if (strcasecmp(envu, "en_US")==0 
		    || strcasecmp(envu, "C")==0
		    || strcasecmp(envu, "POSIX")==0) {
			return imperial;
		}
		/* Other, must be metric */
		return metric;
	}
	/* TODO: allow a compile time default here */
	return unspecified;
}

struct gps_data_t *gps_open(const char *host, const char *port)
/* open a connection to a gpsd daemon */
{
    struct gps_data_t *gpsdata = (struct gps_data_t *)calloc(sizeof(struct gps_data_t), 1);

    /*@ -branchstate @*/
    if (!gpsdata)
	return NULL;
    if (!host)
	host = "127.0.0.1";
    if (!port)
	port = DEFAULT_GPSD_PORT;

    if ((gpsdata->gps_fd = netlib_connectsock(host, port, "tcp")) < 0) {
	errno = gpsdata->gps_fd;
	(void)free(gpsdata);
	return NULL;
    }

    gpsdata->status = STATUS_NO_FIX;
    gps_clear_fix(&gpsdata->fix);
    return gpsdata;
    /*@ +branchstate @*/
}

int gps_close(struct gps_data_t *gpsdata)
/* close a gpsd connection */
{
    int retval = close(gpsdata->gps_fd);
    if (gpsdata->gps_id) {
	(void)free(gpsdata->gps_id);
	gpsdata->gps_id = NULL;
    }
    gpsdata->gps_device[0] = '\0';
    if (gpsdata->devicelist) {
	int i;
	for (i = 0; i < gpsdata->ndevices; i++)
	    /*@i1@*/(void)free(gpsdata->devicelist[i]);
	(void)free(gpsdata->devicelist);
	gpsdata->devicelist = NULL;
	gpsdata->ndevices = -1;
    }    
    /*@i@*/(void)free(gpsdata);
    return retval;
}

void gps_set_raw_hook(struct gps_data_t *gpsdata, 
		      void (*hook)(struct gps_data_t *, char *, size_t len, int level))
{
    gpsdata->raw_hook = hook;
}

/*@ -branchstate -usereleased @*/
static void gps_unpack(char *buf, struct gps_data_t *gpsdata)
/* unpack a daemon response into a status structure */
{
    char *ns, *sp, *tp;
    int i;

    for (ns = buf; ns; ns = strstr(ns+1, "GPSD")) {
	if (/*@i1@*/strncmp(ns, "GPSD", 4) == 0) {
	    /* the following should execute each time we have a good next sp */
	    for (sp = ns + 5; *sp != '\0'; sp = tp+1) {
		tp = sp + strcspn(sp, ",\r\n");
		if (*tp == '\0') tp--;
		else *tp = '\0';

		switch (*sp) {
		case 'A':
		    if (sp[2] == '?') {
			    gpsdata->fix.altitude = NAN;
		    } else {
		        (void)sscanf(sp, "A=%lf", &gpsdata->fix.altitude);
		        gpsdata->set |= ALTITUDE_SET;
		    }
		    break;
		case 'B':
		    if (sp[2] == '?') {
			gpsdata->baudrate = gpsdata->stopbits = 0;
		    } else
			(void)sscanf(sp, "B=%u %*d %*s %u", 
			       &gpsdata->baudrate, &gpsdata->stopbits);
		    break;
		case 'C':
		    if (sp[2] == '?')
			gpsdata->mincycle = gpsdata->cycle = 0;
		    else {
			if (sscanf(sp, "C=%lf %lf", 
				     &gpsdata->cycle,
				   &gpsdata->mincycle) < 2)
			    gpsdata->mincycle = gpsdata->cycle;
		    }
		    break;
		case 'D':
		    if (sp[2] == '?') 
			gpsdata->fix.time = NAN;
		    else {
			gpsdata->fix.time = iso8601_to_unix(sp+2);
			gpsdata->set |= TIME_SET;
		    }
		    break;
		case 'E':
		    gpsdata->epe = gpsdata->fix.eph = gpsdata->fix.epv = NAN;
		    /* epe should always be present if eph or epv is */
		    if (sp[2] != '?') {
			char epe[20], eph[20], epv[20];
		        (void)sscanf(sp, "E=%s %s %s", epe, eph, epv);
#define DEFAULT(val) (val[0] == '?') ? NAN : atof(val)
			    /*@ +floatdouble @*/
			    gpsdata->epe = DEFAULT(epe);
			    gpsdata->fix.eph = DEFAULT(eph);
			    gpsdata->fix.epv = DEFAULT(epv);
			    /*@ -floatdouble @*/
#undef DEFAULT
		    }
		    break;
		case 'F':
		    /*@ -mustfreeonly */
		    if (sp[2] == '?') 
			gpsdata->gps_device[0] = '\0';
		    else {
			/*@ -mayaliasunique @*/
			strncpy(gpsdata->gps_device, sp+2, PATH_MAX);
			/*@ +mayaliasunique @*/
			gpsdata->set |= DEVICE_SET;
		    }
		    /*@ +mustfreeonly */
		    break;
		case 'I':
		    /*@ -mustfreeonly */
		    if (gpsdata->gps_id)
			free(gpsdata->gps_id);
		    if (sp[2] == '?')
			gpsdata->gps_id = NULL;
		    else {
			gpsdata->gps_id = strdup(sp+2);
			gpsdata->set |= DEVICEID_SET;
		    }
		    /*@ +mustfreeonly */
		    break;
		case 'K':
		    if (gpsdata->devicelist) {
			for (i = 0; i < gpsdata->ndevices; i++)
			    /*@i1@*/(void)free(gpsdata->devicelist[i]);
			(void)free(gpsdata->devicelist);
			gpsdata->devicelist = NULL;
			gpsdata->ndevices = -1;
			gpsdata->set |= DEVICELIST_SET;
		    }
		    if (sp[2] != '?') {
			/*@ -nullderef -nullpass -mustfreeonly -dependenttrans @*/
			char *rc = strdup(sp);
			char *sp2 = rc;
			char *ns2 = ns;
			gpsdata->ndevices = (int)strtol(sp2+2, &sp2, 10);
			gpsdata->devicelist = (char **)calloc(
			    (size_t)gpsdata->ndevices,
			    sizeof(char **));
			/*@ -nullstate -mustfreefresh @*/
			gpsdata->devicelist[i=0] = strdup(strtok_r(sp2+1, " \r\n", &ns2));
			while ((sp2 = strtok_r(NULL, " \r\n",  &ns2)))
			    gpsdata->devicelist[++i] = strdup(sp2);
			free(rc);
			/*@ +nullstate +mustfreefresh @*/
			/*@ +nullderef +nullpass +dependenttrans +mustfreeonly @*/
			gpsdata->set |= DEVICELIST_SET;
		    }
		    break;
		case 'M':
		    if (sp[2] == '?') {
		        gpsdata->fix.mode = MODE_NOT_SEEN;
		    } else {
		        gpsdata->fix.mode = atoi(sp+2);
		        gpsdata->set |= MODE_SET;
		    }
		    break;
		case 'N':
		    if (sp[2] == '?') 
			gpsdata->driver_mode = MODE_NMEA;
		    else
			gpsdata->driver_mode = (unsigned)atoi(sp+2);
		    break;
		case 'O':
		    if (sp[2] == '?') {
			gpsdata->set = MODE_SET | STATUS_SET;
			gpsdata->status = STATUS_NO_FIX;
			gps_clear_fix(&gpsdata->fix);
		    } else {
			struct gps_fix_t nf;
			char tag[MAXTAGLEN+1], alt[20];
			char eph[20], epv[20], track[20],speed[20], climb[20];
			char epd[20], eps[20], epc[20], mode[2];
			char timestr[20], ept[20], lat[20], lon[20];
			int st = sscanf(sp+2, 
			       "%8s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %19s %1s",
				tag, timestr, ept, lat, lon,
			        alt, eph, epv, track, speed, climb,
			        epd, eps, epc, mode);
			if (st >= 14) {
#define DEFAULT(val) (val[0] == '?') ? NAN : atof(val)
			    /*@ +floatdouble @*/
			    nf.time = DEFAULT(timestr);
			    nf.latitude = DEFAULT(lat);
			    nf.longitude = DEFAULT(lon);
			    nf.ept = DEFAULT(ept);
			    nf.altitude = DEFAULT(alt);
			    nf.eph = DEFAULT(eph);
			    nf.epv = DEFAULT(epv);
			    nf.track = DEFAULT(track);
			    nf.speed = DEFAULT(speed);
			    nf.climb = DEFAULT(climb);
			    nf.epd = DEFAULT(epd);
			    nf.eps = DEFAULT(eps);
			    nf.epc = DEFAULT(epc);
			    /*@ -floatdouble @*/
#undef DEFAULT
			    if (st >= 15)
				nf.mode = (mode[0] == '?') ? MODE_NOT_SEEN : atoi(mode);
			    else
				nf.mode = (alt[0] == '?') ? MODE_2D : MODE_3D;
			    if (alt[0] != '?')
				gpsdata->set |= ALTITUDE_SET | CLIMB_SET;
			    if (isnan(nf.eph)==0)
				gpsdata->set |= HERR_SET;
			    if (isnan(nf.epv)==0)
				gpsdata->set |= VERR_SET;
			    if (isnan(nf.track)==0)
				gpsdata->set |= TRACK_SET | SPEED_SET;
			    if (isnan(nf.eps)==0)
				gpsdata->set |= SPEEDERR_SET;
			    if (isnan(nf.epc)==0)
				gpsdata->set |= CLIMBERR_SET;
			    gpsdata->fix = nf;
			    (void)strlcpy(gpsdata->tag, tag, MAXTAGLEN+1);
			    gpsdata->set |= TIME_SET|TIMERR_SET|LATLON_SET|MODE_SET;
			    gpsdata->status = STATUS_FIX;
			    gpsdata->set |= STATUS_SET;
			}
		    }
		    break;
		case 'P':
		    if (sp[2] == '?') {
			   gpsdata->fix.latitude = NAN;
			   gpsdata->fix.longitude = NAN;
		    } else {
		        (void)sscanf(sp, "P=%lf %lf",
			   &gpsdata->fix.latitude, &gpsdata->fix.longitude);
		        gpsdata->set |= LATLON_SET;
		    }
		    break;
		case 'Q':
		    if (sp[2] == '?') {
			   gpsdata->satellites_used = 0;
			   gpsdata->pdop = 0;
			   gpsdata->hdop = 0;
			   gpsdata->vdop = 0;
		    } else {
		        (void)sscanf(sp, "Q=%d %lf %lf %lf %lf %lf",
			       &gpsdata->satellites_used,
			       &gpsdata->pdop,
			       &gpsdata->hdop,
			       &gpsdata->vdop,
			       &gpsdata->tdop,
			       &gpsdata->gdop);
		        gpsdata->set |= HDOP_SET | VDOP_SET | PDOP_SET;
		    }
		    break;
		case 'S':
		    if (sp[2] == '?') {
		        gpsdata->status = -1;
		    } else {
		        gpsdata->status = atoi(sp+2);
		        gpsdata->set |= STATUS_SET;
		    }
		    break;
		case 'T':
		    if (sp[2] == '?') {
		        gpsdata->fix.track = NAN;
		    } else {
		        (void)sscanf(sp, "T=%lf", &gpsdata->fix.track);
		        gpsdata->set |= TRACK_SET;
		    }
		    break;
		case 'U':
		    if (sp[2] == '?') {
		        gpsdata->fix.climb = NAN;
		    } else {
		        (void)sscanf(sp, "U=%lf", &gpsdata->fix.climb);
		        gpsdata->set |= CLIMB_SET;
		    }
		    break;
		case 'V':
		    if (sp[2] == '?') {
		        gpsdata->fix.speed = NAN;
		    } else {
		        (void)sscanf(sp, "V=%lf", &gpsdata->fix.speed);
			/* V reply is in kt, fix.speed is in metres/sec */
			gpsdata->fix.speed = gpsdata->fix.speed / MPS_TO_KNOTS;
		        gpsdata->set |= SPEED_SET;
		    }
		    break;
		case 'X':
		    if (sp[2] == '?') 
			gpsdata->online = -1;
		    else {
			(void)sscanf(sp, "X=%lf", &gpsdata->online);
			gpsdata->set |= ONLINE_SET;
		    }
		    break;
		case 'Y':
		    if (sp[2] == '?') {
			gpsdata->satellites = 0;
		    } else {
			int j, i1, i2, i3, i4, i5;
			int PRN[MAXCHANNELS];
			int elevation[MAXCHANNELS], azimuth[MAXCHANNELS];
			int ss[MAXCHANNELS], used[MAXCHANNELS];
			char tag[MAXTAGLEN+1], timestamp[21];

			(void)sscanf(sp, "Y=%8s %20s %d ", 
			       tag, timestamp, &gpsdata->satellites);
			(void)strncpy(gpsdata->tag, tag, MAXTAGLEN);
			if (timestamp[0] != '?') {
			    gpsdata->sentence_time = atof(timestamp);
			    gpsdata->set |= TIME_SET;
			}
			for (j = 0; j < gpsdata->satellites; j++) {
			    PRN[j]=elevation[j]=azimuth[j]=ss[j]=used[j]=0;
			}
			for (j = 0, gpsdata->satellites_used = 0; j < gpsdata->satellites; j++) {
			    if ((sp != NULL) && ((sp = strchr(sp, ':')) != NULL)) {
				sp++;
				(void)sscanf(sp, "%d %d %d %d %d", &i1, &i2, &i3, &i4, &i5);
				PRN[j] = i1;
				elevation[j] = i2; azimuth[j] = i3;
				ss[j] = i4; used[j] = i5;
				if (i5 == 1)
				    gpsdata->satellites_used++;
			    }
			}
			/*@ -compdef @*/
			memcpy(gpsdata->PRN, PRN, sizeof(PRN));
			memcpy(gpsdata->elevation, elevation, sizeof(elevation));
			memcpy(gpsdata->azimuth, azimuth,sizeof(azimuth));
			memcpy(gpsdata->ss, ss, sizeof(ss));
			memcpy(gpsdata->used, used, sizeof(used));
			/*@ +compdef @*/
		    }
		    gpsdata->set |= SATELLITE_SET;
		    break;
		case 'Z':
		    gpsdata->profiling = (sp[2] == '1');
		    break;
		case '$':
		    if (gpsdata->profiling != true)
			break;
		    /*@ +matchanyintegral -formatcode @*/
		    (void)sscanf(sp, "$=%8s %zd %lf %lf %lf %lf %lf %lf", 
			   gpsdata->tag,
			   &gpsdata->sentence_length,
			   &gpsdata->fix.time, 
			   &gpsdata->d_xmit_time, 
			   &gpsdata->d_recv_time, 
			   &gpsdata->d_decode_time, 
			   &gpsdata->poll_time, 
			   &gpsdata->emit_time);
		    /*@ -matchanyintegral +formatcode @*/
		    break;
		}
	    }
	}
    }

/*@ -nullstate -compdef @*/
    if (gpsdata->raw_hook)
	gpsdata->raw_hook(gpsdata, buf, strlen(buf),  1);
    if (gpsdata->thread_hook)
	gpsdata->thread_hook(gpsdata, buf, strlen(buf), 1);
}
/*@ +nullstate +compdef @*/
/*@ -branchstate +usereleased @*/

/*
 * return: 0, success
 *        -1, read error
 */

int gps_poll(struct gps_data_t *gpsdata)
/* wait for and read data being streamed from the daemon */ 
{
    char	buf[BUFSIZ];
    ssize_t	n;
    double received = 0;

    /* the daemon makes sure that every read is NUL-terminated */
    n = read(gpsdata->gps_fd, buf, sizeof(buf)-1);
    if (n <= 0) {
	 /* error or nothing read */    
	return -1;
    }
    buf[n] = '\0';

    received = gpsdata->online = timestamp();
    gps_unpack(buf, gpsdata);
    if (gpsdata->profiling)
    {
	gpsdata->c_decode_time = received - gpsdata->fix.time;
	gpsdata->c_recv_time = timestamp() - gpsdata->fix.time;
    }
    return 0;
}

int gps_query(struct gps_data_t *gpsdata, const char *fmt, ... )
/* query a gpsd instance for new data */
{
    char buf[BUFSIZ];
    va_list ap;

    va_start(ap, fmt);
    (void)vsnprintf(buf, sizeof(buf)-2, fmt, ap);
    va_end(ap);
    if (buf[strlen(buf)-1] != '\n')
	(void)strlcat(buf, "\n", BUFSIZ);
    if (write(gpsdata->gps_fd, buf, strlen(buf)) <= 0)
	return -1;
    return gps_poll(gpsdata);
}

#ifdef HAVE_LIBPTHREAD
static /*@null@*/void *poll_gpsd(void *args) 
/* helper for the thread launcher */
{
    int oldtype, oldstate;
    int res;
    struct gps_data_t *gpsdata;

    /* set thread parameters */
    /*@ -compdef @*/
    /*@ -unrecog (splint has no pthread declarations as yet) @*/
    (void)pthread_setcancelstate(PTHREAD_CANCEL_ENABLE,&oldstate);
    (void)pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS,&oldtype); /* we want to be canceled also when blocked on gps_poll() */
    /*@ +unrecog @*/
    /*@ +compdef @*/
    gpsdata = (struct gps_data_t *) args;
    do {
	res = gps_poll(gpsdata); /* this is not actually polling */
    } while 
	(res == 0);
    /* if we are here an error occured with gpsd */
    return NULL;
}

int gps_set_callback(struct gps_data_t *gpsdata, 
		     void (*callback)(struct gps_data_t *sentence, char *buf, size_t len, int level),
		     pthread_t *handler) 
/* set an asynchronous callback and launch a thread for it */
{
    (void)gps_query(gpsdata,"w+\n");	/* ensure gpsd is in watcher mode, so we'll have data to read */
    if (gpsdata->thread_hook != NULL) {
	gpsdata->thread_hook = callback;
	return 0;
    }
    gpsdata->thread_hook = callback;

    /* start the thread which will read data from gpsd */
    /*@ -unrecog (splint has no pthread declarations as yet */
    return pthread_create(handler,NULL,poll_gpsd,(void*)gpsdata);
    /*@ +unrecog @*/
}

int gps_del_callback(struct gps_data_t *gpsdata, pthread_t *handler)
/* delete asynchronous callback and kill its thread */
{
    /*@ -nullstate @*/
    int res;

    /*@i@*/res = pthread_cancel(*handler);	/* we cancel the whole thread */
    /*@i1@*/pthread_join(*handler, NULL);	/* wait for thread to actually terminate */
    gpsdata->thread_hook = NULL;	/* finally we cancel the callback */
    if (res == 0) 			/* tell gpsd to stop sending data */
	/*@i1@*/(void)gps_query(gpsdata,"w-\n");	/* disable watcher mode */
    return res;
    /*@ +nullstate @*/
}
#endif /* HAVE_LIBPTHREAD */

#ifdef TESTMAIN
/*
 * A simple command-line exerciser for the library.
 * Not really useful for anything but debugging.
 */
static void data_dump(struct gps_data_t *collect, time_t now)
{
    char *status_values[] = {"NO_FIX", "FIX", "DGPS_FIX"};
    char *mode_values[] = {"", "NO_FIX", "MODE_2D", "MODE_3D"};

    if (collect->set & ONLINE_SET)
	printf("online: %lf\n", collect->online);
    if (collect->set & LATLON_SET)
	printf("P: lat/lon: %lf %lf\n", collect->fix.latitude, collect->fix.longitude);
    if (collect->set & ALTITUDE_SET)
	printf("A: altitude: %lf  U: climb: %lf\n", 
	       collect->fix.altitude, collect->fix.climb);
    if (!isnan(collect->fix.track))
	printf("T: track: %lf  V: speed: %lf\n", 
	       collect->fix.track, collect->fix.speed);
    if (collect->set & STATUS_SET)
	printf("S: status: %d (%s)\n", 
	       collect->status, status_values[collect->status]);
    if (collect->fix.mode & MODE_SET)
	printf("M: mode: %d (%s)\n", 
	   collect->fix.mode, mode_values[collect->fix.mode]);
    if (collect->fix.mode & (HDOP_SET | VDOP_SET | PDOP_SET))
	printf("Q: satellites %d, pdop=%lf, hdop=%lf, vdop=%lf\n",
	   collect->satellites_used, 
	   collect->pdop, collect->hdop, collect->vdop);

    if (collect->set & SATELLITE_SET) {
	int i;

	printf("Y: satellites in view: %d\n", collect->satellites);
	for (i = 0; i < collect->satellites; i++) {
	    printf("    %2.2d: %2.2d %3.3d %3.3d %c\n", collect->PRN[i], collect->elevation[i], collect->azimuth[i], collect->ss[i], collect->used[i]? 'Y' : 'N');
	}
    }
    if (collect->set & DEVICE_SET)
	printf("Device is %s\n", collect->gps_device);
    if (collect->set & DEVICEID_SET)
	printf("GPSD ID is %s\n", collect->gps_id);
    if (collect->set & DEVICELIST_SET) {
	int i;
	printf("%d devices:\n", collect->ndevices);
	for (i = 0; i < collect->ndevices; i++) {
	    printf("%d: %s\n", collect->ndevices, collect->devicelist[i]);
	}
    }
	
}

static void dumpline(struct gps_data_t *ud UNUSED, char *buf,
		     size_t ulen UNUSED, int level UNUSED)
{
    puts(buf);
}

#ifndef S_SPLINT_S
#include <unistd.h>
#endif /* S_SPLINT_S */

int main(int argc, char *argv[])
{
    struct gps_data_t *collect;
    char buf[BUFSIZ];

    collect = gps_open(NULL, 0);
    gps_set_raw_hook(collect, dumpline);
    if (optind < argc) {
	strlcpy(buf, argv[optind], BUFSIZ);
	strlcat(buf,"\n", BUFSIZ);
	gps_query(collect, buf);
	data_dump(collect, time(NULL));
    } else {
	int	tty = isatty(0);

	if (tty)
	    (void)fputs("This is the gpsd exerciser.\n", stdout);
	for (;;) {
	    if (tty)
		(void)fputs("> ", stdout);
	    if (fgets(buf, sizeof(buf), stdin) == NULL) {
		if (tty)
		    putchar('\n');
		break;
	    }
	    collect->set = 0;
	    gps_query(collect, buf);
	    data_dump(collect, time(NULL));
	}
    }

    (void)gps_close(collect);
    return 0;
}

#endif /* TESTMAIN */