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Issue 241 - Catch up with new gpsd incompatbilities.
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@wb2osz
wb2osz committed Jun 21, 2020
1 parent e2b32d1 commit 74cf91c
Showing 1 changed file with 81 additions and 25 deletions.
106 changes: 81 additions & 25 deletions src/dwgpsd.c
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@@ -1,7 +1,7 @@
//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
// Copyright (C) 2013, 2014, 2015 John Langner, WB2OSZ
// Copyright (C) 2013, 2014, 2015, 2020 John Langner, WB2OSZ
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
Expand Down Expand Up @@ -55,13 +55,11 @@

#include <gps.h>

// Debian bug report: direwolf (1.2-1) FTBFS with libgps22 as part of the gpsd transition (#803605):
// dwgps.c claims to only support GPSD_API_MAJOR_VERSION 5, but also builds successfully with
// GPSD_API_MAJOR_VERSION 6 provided by libgps22 when the attached patch is applied.

// Also compatible with API 7 & 8 with conditional compilation later.
// An incompatibility was introduced with version 7
// and again with 9 and again with 10.

#if GPSD_API_MAJOR_VERSION < 5 || GPSD_API_MAJOR_VERSION > 8
#if GPSD_API_MAJOR_VERSION < 5 || GPSD_API_MAJOR_VERSION > 10
#error libgps API version might be incompatible.
#endif

Expand Down Expand Up @@ -116,7 +114,7 @@ static void * read_gpsd_thread (void *arg);
* shared region via dwgps_put_data.
*
* The application calls dwgps_read to get the most
8 recent information.
* recent information.
*
*--------------------------------------------------------------------*/

Expand All @@ -126,7 +124,7 @@ static void * read_gpsd_thread (void *arg);
* Originally, I wanted to use the shared memory interface to gpsd
* because it is simpler and more efficient. Just access it when we
* actually need the data and we don't have a lot of extra unnecessary
* busy work going on.
* busy work going on constantly polling it when we don't need the information.
*
* The current version of gpsd, supplied with Raspian (Wheezy), is 3.6 from back in
* May 2012, is missing support for the shared memory interface.
Expand All @@ -142,13 +140,28 @@ static void * read_gpsd_thread (void *arg);
* cd gpsd-3.11
* scons prefix=/usr libdir=lib/arm-linux-gnueabihf shm_export=True python=False
* sudo scons udev-install
*
*
* For now, we will use the socket interface. Maybe get back to this again someday.
*
* Update: January 2016.
*
* I'm told that the shared memory interface might work in Raspian, Jessie version.
* Haven't tried it yet.
*
* June 2020: This is how to build the most recent.
*
* Based on https://www.satsignal.eu/raspberry-pi/UpdatingGPSD.html
*
* git clone https://gitlab.com/gpsd/gpsd.git gpsd-gitlab
* cd gpsd-gitlab
* scons --config=force
* scons
* sudo scons install
*
* The problem we have here is that the library is put in /usr/local/lib and direwolf
* can't find it there. Solution is to define environment variable:
*
* export LD_LIBRARY_PATH=/use/local/lib
*/


Expand Down Expand Up @@ -232,7 +245,7 @@ int dwgpsd_init (struct misc_config_s *pconfig, int debug)
*
*--------------------------------------------------------------------*/

#define TIMEOUT 30
#define TIMEOUT 15

#if ENABLE_GPSD

Expand All @@ -255,10 +268,19 @@ static void * read_gpsd_thread (void *arg)

while (1) {

// Example code found here:
// https://lists.nongnu.org/archive/html/gpsd-dev/2017-11/msg00001.html

if ( ! gps_waiting(&gpsdata, TIMEOUT * 1000000)) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("GPSD: Timeout waiting for GPS data.\n");
/* Fall thru to read which should get error and bail out. */
dw_printf ("------------------------------------------\n");
dw_printf ("dwgpsd: Timeout waiting for GPS data.\n");
dw_printf ("Is GPSD daemon running?\n");
dw_printf ("Troubleshooting tip: Try running cgps or xgps.\n");
dw_printf ("------------------------------------------\n");
info.fix = DWFIX_ERROR;
SLEEP_MS(5000);
continue;
}

// https://github.com/wb2osz/direwolf/issues/196
Expand Down Expand Up @@ -290,16 +312,47 @@ static void * read_gpsd_thread (void *arg)
break; // Jump out of loop and terminate thread.
}

#if GPSD_API_MAJOR_VERSION >= 9

// The gps.h revision history says:
// * mark altitude in gps_fix_t as deprecated and undefined
// This seems really stupid to me.
// If it is deprecated and undefined then take it out. Someone trying to use
// it would get a compile error and know that something needs to be done.
// Instead we all just go merrily on our way using a field that is [allegedly] undefined.
// Why not simply add more variables with different definitions of altitude
// and keep the original variable working as it always did?
// If it is truly undefined, as the comment would have us believe, numerous
// people will WASTE VAST AMOUNTS OF TIME pondering why altitude is now broken in
// their applications.

#define stupid_altitude altMSL
#else
#define stupid_altitude altitude
#endif

#if GPSD_API_MAJOR_VERSION >= 10

// They did it again. Whimsical incompatibilities that cause
// pain and aggravation for everyone trying to use this library.
//
// error: ‘struct gps_data_t’ has no member named ‘status’
//
// Yes, I can understand that it is a more logical place but it breaks
// all existing code that uses this.
// I'm really getting annoyed about wasting so much time on keeping up with all
// of these incompatibilities that are completely unnecessary.

#define stupid_status fix.status
#else
#define stupid_status status
#endif

// Inform user about change in fix status.

switch (gpsdata.fix.mode) {
default:
case MODE_NOT_SEEN:
if (info.fix >= DWFIX_2D) {
text_color_set(DW_COLOR_INFO);
dw_printf ("GPSD: Lost location fix.\n");
}
info.fix = DWFIX_NOT_SEEN;
break;

case MODE_NO_FIX:
if (info.fix >= DWFIX_2D) {
text_color_set(DW_COLOR_INFO);
Expand All @@ -325,21 +378,23 @@ static void * read_gpsd_thread (void *arg)
break;
}

/* Data is available. */
// TODO: what is gpsdata.status?


if (gpsdata.status >= STATUS_FIX && gpsdata.fix.mode >= MODE_2D) {
if (gpsdata.stupid_status >= STATUS_FIX && gpsdata.fix.mode >= MODE_2D) {

info.dlat = isnan(gpsdata.fix.latitude) ? G_UNKNOWN : gpsdata.fix.latitude;
info.dlon = isnan(gpsdata.fix.longitude) ? G_UNKNOWN : gpsdata.fix.longitude;
info.track = isnan(gpsdata.fix.track) ? G_UNKNOWN : gpsdata.fix.track;
info.speed_knots = isnan(gpsdata.fix.speed) ? G_UNKNOWN : (MPS_TO_KNOTS * gpsdata.fix.speed);

if (gpsdata.fix.mode >= MODE_3D) {
info.altitude = isnan(gpsdata.fix.altitude) ? G_UNKNOWN : gpsdata.fix.altitude;
info.altitude = isnan(gpsdata.fix.stupid_altitude) ? G_UNKNOWN : gpsdata.fix.stupid_altitude;
}
}
else {
// Keep the last known location.
// Using info.fix, the caller knows if the location is current (DWFIX_[23]D),
// last known (DWFIX_NONE), or never known (DWFIX_NOT_SEEN).
info.fix = DWFIX_NO_FIX;
}

info.timestamp = time(NULL);
if (s_debug >= 2) {
Expand Down Expand Up @@ -373,6 +428,7 @@ void dwgpsd_term (void) {

#if ENABLE_GPSD

gps_stream (&gpsdata, WATCH_DISABLE, NULL);
gps_close (&gpsdata);

#endif
Expand Down

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