j1939-vehicle-position-srv: Introduce J1939 and NMEA 2000 Vehicle Position Server

This patch adds `j1939-vehicle-position-srv`, a server for sending
vehicle position data over CAN using J1939 or NMEA 2000 protocols. It
retrieves GPS data from gpsd or simulates data if gpsd is unavailable.
By default, it operates in J1939 profile but can switch to NMEA 2000
with the `-p nmea2000` option.

Usage Examples:
1. With gpsd:
   j1939acd -r 64-95 -c /tmp/1122334455667789.jacd 1122334455667789 vcan0 &
   j1939-vehicle-position-srv -i vcan0 -n 0x1122334455667789

2. In simulation mode without gpsd:
   j1939-vehicle-position-srv -i vcan0 -s -p nmea2000

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
[Yegor: add CMakeLists.txt integration]
Co-developed-by: Yegor Yefremov <yegorslists@googlemail.com>

CMakeLists.txt

@@ -14,6 +14,12 @@ endif()
 
 # Add an option to enable treating warnings as errors
 option(ENABLE_WERROR "Treat all compiler warnings as errors" OFF)
+option(ENABLE_GPS "Enable GPS support" OFF)
+
+find_package(PkgConfig REQUIRED)
+if(ENABLE_GPS)
+  pkg_check_modules(GPS REQUIRED libgps)
+endif()
 
 if(ENABLE_WERROR)
   add_compile_options(-Werror)
@@ -67,6 +73,10 @@ set(PROGRAMS_J1939_TIMEDATE
   j1939-timedate-cli
 )
 
+set(PROGRAMS_J1939_VEHICLE_POSITION
+  j1939-vehicle-position-srv
+)
+
 set(PROGRAMS_ISOBUSFS
   isobusfs-srv
   isobusfs-cli
@@ -191,6 +201,24 @@ if(NOT ANDROID)
     j1939-timedate-srv
     DESTINATION ${CMAKE_INSTALL_BINDIR})
 
+  if(ENABLE_GPS)
+    set(PUBLIC_HEADER_J1939_VEHICLE_POSITION
+      j1939_vehicle_position/j1939_vehicle_position_cmn.h
+    )
+
+    add_executable(j1939-vehicle-position-srv
+      j1939_vehicle_position/j1939_vehicle_position_srv.c
+    )
+
+    target_link_libraries(j1939-vehicle-position-srv
+      PRIVATE can j1939 ${GPS_LIBRARIES}
+    )
+
+    install(TARGETS
+      j1939-vehicle-position-srv
+      DESTINATION ${CMAKE_INSTALL_BINDIR})
+  endif()
+
 endif()
 
 add_library(can STATIC

Makefile

@@ -67,6 +67,9 @@ PROGRAMS_J1939_TIMEDATE := \
 	j1939-timedate-srv \
 	j1939-timedate-cli
 
+PROGRAMS_J1939_VEHICLE_POSITION := \
+	j1939-vehicle-position-srv
+
 PROGRAMS_ISOBUSFS := \
 	isobusfs-srv \
 	isobusfs-cli
@@ -98,6 +101,7 @@ PROGRAMS_SLCAN := \
 PROGRAMS := \
 	$(PROGRAMS_CANGW) \
 	$(PROGRAMS_J1939_TIMEDATE) \
+	$(PROGRAMS_J1939_VEHICLE_POSITION) \
 	$(PROGRAMS_ISOBUSFS) \
 	$(PROGRAMS_ISOTP) \
 	$(PROGRAMS_J1939) \
@@ -126,7 +130,8 @@ endif
 all: $(PROGRAMS)
 
 clean:
-	rm -f $(PROGRAMS) *.o mcp251xfd/*.o isobusfs/*.o j1939_timedate/*.o
+	rm -f $(PROGRAMS) *.o mcp251xfd/*.o isobusfs/*.o j1939_timedate/*.o \
+		j1939_vehicle_position/*.o
 
 install:
 	mkdir -p $(DESTDIR)$(PREFIX)/bin
@@ -153,6 +158,8 @@ isobusfs_srv.o:	lib.h libj1939.h
 isobusfs_c.o:	lib.h libj1939.h
 j1939_timedate_srv.o: lib.h libj1939.h
 j1939_timedate_cli.o: lib.h libj1939.h
+j1939_vehicle_position_srv.o: lib.h libj1939.h
+
 canframelen.o:  canframelen.h
 
 asc2log:	asc2log.o	lib.o
@@ -182,6 +189,12 @@ j1939-timedate-cli:	lib.o \
 			j1939_timedate/j1939_timedate_cli.o
 		$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@
 
+j1939-vehicle-position-srv: \
+			lib.o \
+			libj1939.o \
+			j1939_vehicle_position/j1939_vehicle_position_srv.o \
+		$(CC) $(LDFLAGS) $^ $(LDLIBS) -lgps -o $@
+
 isobusfs-srv:	lib.o \
 		libj1939.o \
 		isobusfs/isobusfs_cmn.o \