AP_HAL: added support for commandline arguments

useful for log replay, specifying log file

libraries/AP_HAL/Util.h

@@ -53,6 +53,11 @@ public:
        then return 0xFFFF. If unknown return 4096
      */
     virtual uint16_t available_memory(void) { return 4096; }
+
+    /**
+       return commandline arguments, if available
+     */
+    virtual void commandline_arguments(uint8_t &argc, char * const *&argv) { argc = 0; }
 };
 
 #endif // __AP_HAL_UTIL_H__

libraries/AP_HAL_Linux/HAL_Linux_Class.cpp

@@ -75,6 +75,7 @@ void HAL_Linux::init(int argc,char* const argv[]) const
     uartA->begin(115200);
     i2c->begin();
     spi->init(NULL);
+    utilInstance.init(argc, argv);
 }
 
 const HAL_Linux AP_HAL_Linux;

libraries/AP_HAL_Linux/Util.h

@@ -7,7 +7,21 @@
 
 class Linux::LinuxUtil : public AP_HAL::Util {
 public:
+    void init(int argc, char * const *argv) {
+        saved_argc = argc;
+        saved_argv = argv;
+    }
+
     bool run_debug_shell(AP_HAL::BetterStream *stream) { return false; }
+
+    /**
+       return commandline arguments, if available
+     */
+    void commandline_arguments(uint8_t &argc, char * const *&argv);
+
+private:
+    int saved_argc;
+    char* const *saved_argv;
 };
 
 #endif // __AP_HAL_LINUX_UTIL_H__