Extend OTA documentation

Signed-off-by: David Gräff <david.graeff@web.de>

docs/advanced-usage/ota.md

@@ -11,6 +11,29 @@ directory.
 Updating or even checking the version is a server initatiated operation, wakaamaNode
 will not perform any checks on its own.
 
+## On Posix/Windows systems
+
+The firmware update object accepts pushed binaries via coap in the default implementation.
+The new binary is saved as "new.current_binary_name". As soon as the update resource is executed,
+the current binary will be moved to "old.current_binary_name" and the "new.current_binary_name"
+takes it place.
+
+The new binary is started with a command line argument "oldpid=PID". It sends a posix signal SIGTERM
+to the old binary via the PID and waits for it to finish.
+
+The old binary waits for SIGTERM and terminates if received.
+If not received in time (because the new binary has startup problems for example), the old executable
+will stay active.
+
+A posix/win32 binary is required to call `void checkIsUpdated(int argc, char** argv)` on startup.
+
+## Arduino OTA
+
+Because memory space is assumed to be limited, the update process accepts a http URI only and does not take
+binaries directly via COAP.
+
+The ESP8266 method `ESPhttpUpdate.update("192.168.0.2", 80, "/arduino.bin");` is used.
+
 ## OTA security
 
 You should only accept an OTA request, if you are connected to a DTLS secured connection

examples/linux_win_with_screen_control/src/main.c

@@ -3,6 +3,8 @@
 #include "client_debug.h"
 #include "network.h"
 #include "screen_object.h"
+// For c++ projects with firmware support
+// #include "object_firmware.hpp"
 
 #include <string.h>
 #include <stdlib.h>
@@ -28,6 +30,9 @@ int main(int argc, char *argv[])
      * We catch Ctrl-C signal for a clean exit
      */
     signal(SIGINT, handle_sigint);
+
+    // For c++ projects with firmware support
+    //checkIsUpdated(argc, argv);
 
     device_instance_t * device_data = lwm2m_device_data_get();
     device_data->manufacturer = "test manufacturer";

src/firmware/arduinoOTA.cpp

@@ -1,11 +1,7 @@
-#define ARDUINO
-#define LWM2M_FIRMWARE_UPGRADES
-
-#include "object_firmware.hpp"
-#include "lwm2m_connect.h"
-
-#if (defined(ARDUINO) || defined(LWM2M_FIRMWARE_UPGRADES))
+#if (defined(ARDUINO) && defined(LWM2M_FIRMWARE_UPGRADES))
 #include <ArduinoOTA.h>
+#include "lwm2m_connect.h"
+#include "object_firmware.hpp"
 
 void writeNewFirmware(DynArray<uint8_t*>& firmware) {}
 

src/lwm2m_objects.hpp

@@ -8,7 +8,7 @@
 #include "wakaama/liblwm2m.h"
 #include "lwm2m_objects.h" // We need the enums of the C-API as well
 #include <inttypes.h>
-#include <cstring>
+#include <string.h>
 #include "macro_helper.h"
 #include <type_traits>
 #include <functional>

src/platform/platform_freertos.c

@@ -40,6 +40,9 @@ void __attribute__((weak)) lwm2m_printf(const char * format, ...)
 {
 
 }
+#else
+void __attribute__((weak)) lwm2m_printf(const char * format, ...) {}
+
 #endif
 
 #endif

test/CMakeLists.txt

@@ -12,7 +12,7 @@
 
 cmake_minimum_required(VERSION 3.1)
 
-project(Lwm2mCLientLibWithLwIP CXX C)
+project(Tests CXX C)
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake")