DataFlash: add ability to log-disarmed

libraries/DataFlash/DataFlash.h

@@ -185,7 +185,13 @@ public:
     uint32_t num_dropped(void) const;
 
     // accesss to public parameters
-    bool log_while_disarmed(void) const { return _params.log_disarmed != 0; }
+    void set_force_log_disarmed(bool force_logging) { _force_log_disarmed = force_logging; }
+    bool log_while_disarmed(void) const {
+        if (_force_log_disarmed) {
+            return true;
+        }
+        return _params.log_disarmed != 0;
+    }
     uint8_t log_replay(void) const { return _params.log_replay; }
     
     vehicle_startup_message_Log_Writer _vehicle_messages;
@@ -304,7 +310,6 @@ private:
 
     void backend_starting_new_log(const DataFlash_Backend *backend);
 
-private:
     static DataFlash_Class *_instance;
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
@@ -329,6 +334,7 @@ private:
     void Prep();
 
     bool _writes_enabled:1;
+    bool _force_log_disarmed:1;
 
     /* support for retrieving logs via mavlink: */