[IMP] hw_blackbox_be: implement support for registered POSBoxes

POSBoxes will be registered with the government. If a POSBox is not
registered it won't load the blackbox driver, preventing communication
with the Fiscal Data Module.

addons/hw_blackbox_be/controllers/main.py

@@ -3,6 +3,8 @@
 
 import logging
 import serial
+import subprocess
+from os.path import isfile
 from os import listdir
 from threading import Thread, Lock
 
@@ -148,6 +150,7 @@ class Blackbox(Thread):
             ser.close()
             return ""
 
+if isfile("/home/pi/registered_blackbox_be"):
     blackbox_thread = Blackbox()
     hw_proxy.drivers['fiscal_data_module'] = blackbox_thread
 
@@ -160,3 +163,7 @@ class BlackboxDriver(hw_proxy.Proxy):
                 response = blackbox_thread._send_to_blackbox(to_send, response_size, blackbox_thread.device_path)
 
             return response
+
+        @http.route('/hw_proxy/request_serial/', type='json', auth='none', cors='*')
+        def request_serial(self):
+            return subprocess.check_output("ifconfig eth0 | grep -o 'HWaddr.*' | sed 's/HWaddr \\(.*\\)/\\1/' | sed 's/://g'", shell=True).rstrip()[-7:]