ubus: display only available information

GPS receivers may not provide all possible data, some take more time
and some are irrelevant for some applications and are never sent by
some GPS receivers (eg. equipment found in maritime context doesn't
report elevation). Only populate attributes for which data is actually
available.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

nmea: parse $GPGLL sentences for position

Some GPS receivers do not send $GPGGA sentence. Parse latitude and
longitude also from $GPGLL sentences.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

nmea: parse $GPZDA sentences for date/time

Some GPS receivers only send $GPZDA sentence for date/time. Parse it
and refactor NMEA-0138 code to avoid code duplication.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

ugps: fix 64-bit time_t

The abs function takes a 32-bit int, which can cause truncation. Fixes
compilation error:

error: absolute value function 'abs' given an argu>
if ((sec < 0) || (abs(cur.tv_sec - tv.tv_sec) > MAX_TIME_OFFSET)) {

Signed-off-by: Rosen Penev <rosenp@gmail.com>

nmea: make sure date is valid

GPS time without date was previously used to set system date:
Tue Oct 10 11:48:21 2000 user.info kernel: [  108.786639] ugps: system time differs from GPS time by more than 5 seconds. Using 2000-10-10T10:48:21 UTC as the new time
Tue Oct 10 11:49:27 2000 user.info kernel: [  174.794699] ugps: system time differs from GPS time by more than 5 seconds. Using 2020-05-26T10:49:27 UTC as the new time

Fix this by ignoring incomplete dates and wait for complete time
information before adjusting system date/time.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

nmea: fix time comparision

Code introduced by commit b88037b ("check timegm return code") compares
GPS-time with tv_sec of freshly zero-initialized struct timeval tv.
Compare with current time instead.

Fixes: b88037b ("check timegm return code")
Signed-off-by: Daniel Golle <daniel@makrotopia.org>

ugps: Fix compilation under 64-bit

strlen returns size_t, not int.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Fix build error caused by enabled extra compiler warnings

 nmea.c:257:16: error: comparison between signed and
     unsigned integer expressions [-Werror=sign-compare]

Signed-off-by: Petr Štetiar <ynezz@true.cz>

Enable extra compiler warnings

Signed-off-by: Petr Štetiar <ynezz@true.cz>

nmea.c: set _BSD_SOURCE to have timegm() & stime() on musl

musl doesn't know _DEFAULT_SOURCE which is used by glibc >= 2.19
to enable timegm() and stime().

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>

check timegm return code

Signed-off-by: John Crispin <john@phrozen.org>

nmea.c: Add null byte to nmea fields

Either the main.c treat them as non-null terminated strings or
nmea adds a null byte to the fields.

Found-by: Coverity
Fixes CID 1431321 1431098

remove deprication warning

In file included from /usr/include/time.h:27:0,
from /src/projects/ugps/nmea.c:21:
/usr/include/features.h:148:3: error: #warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE" [-Werror=cpp]

Signed-off-by: John Crispin <john@phrozen.org>

ugps: Only convert lat and lon to negative after parsing

This is a bugfix for package ugps.

Current code parses following GPRMC

$GPRMC,185834.0,A,2335.766399,S,04635.923564,W,0.0,,191017,0.0,E,A*20

as

position: -22.929440 -45.932056

with this fix it's being parsed correctly as

position: -23.596106 -46.598721

Signed-off-by: Giovani Milanez Espindola <gespindola@advantech-bb.com>
>From 092b311a3c8911ce9da3f913787b77397e88b4a8 Mon Sep 17 00:00:00 2001
From: Giovani Espindola <gespindola@advantech-bb.com>
Date: Thu, 19 Oct 2017 15:54:05 -0200
Subject: [PATCH] Only convert lat and lon to negative after parsing

link libm to fix build error

Signed-off-by: Felix Fietkau <nbd@nbd.name>

Switched from strptime to sscanf, added command line switch to set system clock and fixed typo

Signed-off-by: Thomas Hogge <thomas@hoogi.de>

ugps: Simplify and fix position computation from GPRMC sentence

Current code parses following GPRMC

  $GPRMC,071305.0,A,5207.76855,N,02104.022546,E,0.0,,270816,0.0,E,A*18

as

  position: 52.117947 21.67042

with this fix it's being parsed correctly as

  position: 52.129475 21.067041

Fixes https://github.com/lede-project/source/issues/279

Signed-off-by: Petr Štetiar <ynezz@true.cz>
Tested-by: Cezary Jackiewicz <cezary@eko.one.pl>

fix ms->deg conversion

Signed-off-by: John Crispin <john@phrozen.org>

fix reading of speed

Signed-off-by: John Crispin <john@phrozen.org>

Allow bigger lat/lng numbers in RMC message

It works now with following message:

  $GPRMC,122536.0,A,4350.237769,N,01826.423315

Signed-off-by: Petr Štetiar <ynezz@true.cz>

Show more useful error message if we can't open GPS device

Signed-off-by: Petr Štetiar <ynezz@true.cz>

Fix typo in error message

Signed-off-by: Petr Štetiar <ynezz@true.cz>

Use strsep for NMEA message tokenization

strtok doesn't parse correctly following message:

  $GPGSA,A,1,,,,,,,,,,,,,,,*1E

Resulting in "datagram has wrong parameter count".

Signed-off-by: Petr Štetiar <ynezz@true.cz>

Bail out if we can't find GPS device

Signed-off-by: Petr Štetiar <ynezz@true.cz>

Switch to ulog for logging and add few commandline params

Signed-off-by: Petr Štetiar <ynezz@true.cz>

cmake: Add proper library and include files search logic for dependecies

Signed-off-by: Petr Štetiar <ynezz@true.cz>

lat/lng format when printing is incorrect

Signed-off-by: Maurice-Jörg Nießen <post@mjniessen.com>

typo fix

Signed-off-by: Maurice-Jörg Nießen <post@mjniessen.com>

Import