fix style issues

2 files changed, 408 insertions, 160 deletions

diff --git a/src/main.c b/src/main.c
index 3110a13..a1cdcfc 100644
--- a/src/main.c
+++ b/src/main.c
@@ -23,8 +23,6 @@ along with
 * @author Christian Grothoff
 * @author Dominik Hofer
 *
-* TODO:
-* - comment code mdb incl. doxygen struct members (hofer)
 */
 #include "config.h"
 #include <stdio.h>
@@ -71,7 +69,9 @@ along with
  */
 #define _(s) (s)
 
-#define BACKEND_POLL_TIMEOUT GNUNET_TIME_UNIT_MINUTES
+/* FIXME Adjusted Time out because low internet connection at 36C3 */
+#define BACKEND_POLL_TIMEOUT GNUNET_TIME_relative_multiply ( \
+    GNUNET_TIME_UNIT_MINUTES, 5)
 
 #define NFC_FAILURE_RETRY_FREQ GNUNET_TIME_UNIT_SECONDS
 
@@ -125,6 +125,7 @@ along with
 /* VMC commands */
 #define VMC_CMD_START 0x02
 #define VMC_CMD_END 0x03
+#define VMC_CMD_RESET 0x10
 
 /**
  * Acknowledgement
@@ -135,6 +136,8 @@ along with
  * Request for configuration.
  */
 #define VMC_CONF 0x11
+#define VMC_READER_CONF 0x00
+#define VMC_SETUP_MAX_MIN_PRICES 0x01
 
 /**
  * Machine is polling for something.
@@ -179,6 +182,9 @@ along with
 
 /* Reader commands */
 
+/* Reader Not Acknowledge */
+#define READER_NACK "FF"
+
 /* Config Data */
 /* Refer to the mdb interface specifications v4.2 p.288 */
 #define READER_CONFIG "01"
@@ -210,8 +216,17 @@ along with
 /* Cancelled Command */
 #define READER_CANCELLED "08"
 
-/* Unused reader commands */
+/* Display Request for Sold Out product */
 #define READER_DISPLAY_REQUEST "02"
+#define READER_DISPLAY_REQUEST_TIME "32"
+#define READER_DISPLAY_SOLD_OUT \
+  "202020202020202050726f6475637420736f6c64206f75742020202020202020"
+#define READER_DISPLAY_INTERNAL_ERROR \
+  "202020496e7465726e616c204572726f72202d2054727920416761696e202020i"
+#define READER_DISPLAY_BACKEND_NOT_REACHABLE \
+  "20202020204261636b656e64206e6f7420726561636861626c65202020202020"
+
+/* Unused reader commands */
 #define READER_SESSION_CANCEL_REQUEST "04"
 #define READER_REVALUE_DENIED "0E"
 
@@ -227,8 +242,14 @@ along with
  */
 struct MdbBlock
 {
+  /**
+   * Data containing a mdb command or the data of an mdb command
+   */
   uint8_t *bin;
 
+  /**
+   * Size of the data referenced by *bin
+   */
   size_t bin_size;
 };
 
@@ -238,10 +259,19 @@ struct MdbBlock
  */
 struct MdbCommand
 {
+  /**
+   * Name of the command for the logging
+   */
   const char *name;
 
+  /**
+   * Data block containing the information about the mdb command
+   */
   struct MdbBlock cmd;
 
+  /**
+   * Data block containing the information about the mdb command data
+   */
   struct MdbBlock data;
 };
 
@@ -361,18 +391,39 @@ struct PaymentActivity
 struct MdbHandle
 {
 
+  /**
+   * Buffer to save the received data from UART
+   */
   uint8_t rxBuffer[MAX_SIZE_RX_BUFFER];
 
+  /**
+   * Buffer to save the data to send via UART
+   */
   uint8_t txBuffer[MAX_SIZE_TX_BUFFER];
 
+  /**
+   * Reference to scheduler task to read from UART
+   */
   struct GNUNET_SCHEDULER_Task *rtask;
 
+  /**
+   * Reference to scheduler task to write to UART
+   */
   struct GNUNET_SCHEDULER_Task *wtask;
 
+  /**
+   * Reference to the mdb cmd which will be sent next
+   */
   const struct MdbCommand *cmd;
 
+  /**
+   * Reference to the mdb cmd which was sent last
+   */
   const struct MdbCommand *last_cmd;
 
+  /**
+   * Current read offset in @e rxBuffer.
+   */
   size_t rx_off;
 
   /**
@@ -386,12 +437,24 @@ struct MdbHandle
    */
   size_t tx_len;
 
+  /**
+   * Time out to wait for an acknoweledge received via the mdb bus
+   */
   struct GNUNET_TIME_Absolute ack_timeout;
 
+  /**
+   * Backup of the config data to restore the configuration of the UART before closing it
+   */
   struct termios uart_opts_backup;
 
+  /**
+   * Indicates if a vend session is running or not
+   */
   int session_running;
 
+  /**
+   * File descriptor to the UART device file
+   */
   int uartfd;
 
 };
@@ -434,6 +497,18 @@ struct Display
 };
 
 /**
+ * Handle for the Cancel Button
+ */
+struct CancelButton
+{
+  /**
+   * File descriptor to read the state of the cancel button gpio pin
+   */
+  int cancelbuttonfd;
+};
+
+
+/**
  * DLL of pending refund operations.
  */
 struct Refund
@@ -515,17 +590,17 @@ static char *currency;
 /**
  * Taler Backend url read from configuration file
  */
-static char *backendBaseUrl;
+static char *backend_base_url;
 
 /**
  * Taler fulfillment url read from configuration file
  */
-static char *fulfillmentUrl;
+static char *fulfillment_url;
 
 /**
  * Fulfillment message to display after successfull payment, read from configuration file
  */
-static char *fulfillmentMsg;
+static char *fulfillment_msg;
 
 /**
  * Authorization for the taler backend
@@ -555,37 +630,57 @@ static struct MdbHandle mdb;
 /**
  * MDB response to the request for configuration.
  */
-static struct MdbCommand readerConfigData;
+static struct MdbCommand cmd_reader_config_data;
 
 /**
  * Ask MDB to begin session (with "infinite" money)
  */
-static struct MdbCommand beginSession;
+static struct MdbCommand cmd_begin_session;
 
 /**
  * Refuse vending request (payment failed)
  */
-static struct MdbCommand denyVend;
+static struct MdbCommand cmd_deny_vend;
 
 /**
  * Approve vending request (payment succeeded)
  */
-static struct MdbCommand approveVend;
+static struct MdbCommand cmd_approve_vend;
 
 /**
  * Confirm cancellation by machine.
  */
-static struct MdbCommand readerCancelled;
+static struct MdbCommand cmd_reader_cancelled;
 
 /**
  * Approve Revalue
  */
-static struct MdbCommand revalueApproved;
+static struct MdbCommand cmd_revalue_approved;
 
 /**
  * Send Revalue Limit Amount
  */
-static struct MdbCommand revalueAmount;
+static struct MdbCommand cmd_revalue_amount;
+
+/**
+ * Send NACK
+ */
+static struct MdbCommand cmd_reader_NACK;
+
+/**
+ * Display Request for Sold Out
+ */
+static struct MdbCommand cmd_reader_display_sold_out;
+
+/**
+ * Display Request for Error Message
+ */
+static struct MdbCommand cmd_reader_display_internal_error;
+
+/**
+ * Display Request for Error Message
+ */
+static struct MdbCommand cmd_reader_display_backend_not_reachable;
 
 /**
  * Terminate session.
@@ -620,12 +715,7 @@ static char backlight_off = '0';
 /**
  * State for the implementation of the 'cancel' button.
  */
-struct CancelButton
-{
-  int cancelbuttonfd;
-};
-
-static struct CancelButton cancelButton;
+static struct CancelButton cancel_button;
 
 /**
  * Name of the UART device with the MDB (i.e. /dev/ttyAMA0).
@@ -817,6 +907,11 @@ cleanup_payment (struct PaymentActivity *pa)
     nfc_abort_command (pa->pnd);
     nfc_close (pa->pnd);
   }
+  if (NULL != cancelbutton_task)
+  {
+    GNUNET_SCHEDULER_cancel (cancelbutton_task);
+    cancelbutton_task = NULL;
+  }
   if (NULL != pa->po)
     TALER_MERCHANT_proposal_cancel (pa->po);
   if (NULL != pa->cpo)
@@ -850,7 +945,7 @@ cleanup_payment (struct PaymentActivity *pa)
  * @brief Shutdown the mdb communication tasks
  */
 static void
-mdb_shutdown ()
+mdb_shutdown (void)
 {
   if (NULL != mdb.rtask)
   {
@@ -917,6 +1012,11 @@ shutdown_task (void *cls)
     cleanup_payment (payment_activity);
     payment_activity = NULL;
   }
+  if (NULL != cancelbutton_task)
+  {
+    GNUNET_SCHEDULER_cancel (cancelbutton_task);
+    cancelbutton_task = NULL;
+  }
   if (NULL != keyboard_task)
   {
     GNUNET_SCHEDULER_cancel (keyboard_task);
@@ -959,18 +1059,18 @@ shutdown_task (void *cls)
       close (qrDisplay.backlightfd);
     qrDisplay.backlightfd = -1;
   }
-  if (0 < cancelButton.cancelbuttonfd)
+  if (0 < cancel_button.cancelbuttonfd)
   {
-    close (cancelButton.cancelbuttonfd);
-    cancelButton.cancelbuttonfd = open ("/sys/class/gpio/unexport",
-                                        O_WRONLY);
-    if (0 > cancelButton.cancelbuttonfd)
+    close (cancel_button.cancelbuttonfd);
+    cancel_button.cancelbuttonfd = open ("/sys/class/gpio/unexport",
+                                         O_WRONLY);
+    if (0 > cancel_button.cancelbuttonfd)
     {
       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                   "Unable to open /gpio/unexport for cancel button\n");
     }
-    (void) write (cancelButton.cancelbuttonfd, "17", 2);
-    close (cancelButton.cancelbuttonfd);
+    (void) write (cancel_button.cancelbuttonfd, "23", 2);
+    close (cancel_button.cancelbuttonfd);
   }
   /* free the allocated productes read from config file */
   if (NULL != products)
@@ -1271,7 +1371,7 @@ check_payment_cb (void *cls,
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "Backend request to /check-payment failed: %u\n",
                 http_status);
-    mdb.cmd = &denyVend;
+    mdb.cmd = &cmd_reader_display_backend_not_reachable;
     run_mdb_event_loop ();
     cleanup_payment (pa);
     GNUNET_assert (payment_activity == pa);
@@ -1281,7 +1381,7 @@ check_payment_cb (void *cls,
 
   if (paid)
   {
-    mdb.cmd = &approveVend;
+    mdb.cmd = &cmd_approve_vend;
     payment_activity->paid = GNUNET_YES;
     run_mdb_event_loop ();
     if ((disable_mdb) && (! disable_tty))
@@ -1335,7 +1435,7 @@ check_payment_again (void *cls)
   pa->delay_pay_task = NULL;
   GNUNET_assert (NULL == pa->cpo);
   pa->cpo = TALER_MERCHANT_check_payment (ctx,
-                                          backendBaseUrl,
+                                          backend_base_url,
                                           pa->order_id,
                                           NULL /* snack machine, no Web crap */,
                                           BACKEND_POLL_TIMEOUT,
@@ -1370,7 +1470,7 @@ proposal_cb (void *cls,
                 "Failed to setup order with backend: %u/%d\n",
                 http_status,
                 (int) ec);
-    mdb.cmd = &denyVend;
+    mdb.cmd = &cmd_reader_display_backend_not_reachable;
     run_mdb_event_loop ();
     cleanup_payment (pa);
     GNUNET_assert (payment_activity == pa);
@@ -1382,7 +1482,7 @@ proposal_cb (void *cls,
               order_id);
   pa->order_id = GNUNET_strdup (order_id);
   pa->cpo = TALER_MERCHANT_check_payment (ctx,
-                                          backendBaseUrl,
+                                          backend_base_url,
                                           pa->order_id,
                                           NULL /* snack machine, no Web crap */,
                                           GNUNET_TIME_UNIT_ZERO,
@@ -1419,8 +1519,8 @@ launch_payment (struct Product *product)
   /* create the fulfillment url, e.g. "taler://fulfillment-success/Enjoy+your+ice+cream!"; */
   GNUNET_asprintf (&fulflmntUrl,
                    "%s%s%s#%s",
-                   fulfillmentUrl,
-                   fulfillmentMsg,
+                   fulfillment_url,
+                   fulfillment_msg,
                    product->description,
                    uuid_s);
   GNUNET_free (uuid_s);
@@ -1444,7 +1544,7 @@ launch_payment (struct Product *product)
   pa->amount = product->price;
   /* put the order on the merchant's backend */
   pa->po = TALER_MERCHANT_order_put (ctx,
-                                     backendBaseUrl,
+                                     backend_base_url,
                                      orderReq,
                                      &proposal_cb,
                                      pa);
@@ -1456,7 +1556,8 @@ launch_payment (struct Product *product)
     GNUNET_free (pa);
     return NULL;
   }
-  if (0 < cancelButton.cancelbuttonfd)
+  /* Start to read the button on the VM to cancel this payment */
+  if (0 < cancel_button.cancelbuttonfd)
     start_read_cancel_button ();
   return pa;
 }
@@ -1534,7 +1635,7 @@ vend_failure ()
   mdb.session_running = GNUNET_NO;
   r = GNUNET_new (struct Refund);
   r->rio = TALER_MERCHANT_refund_increase (ctx,
-                                           backendBaseUrl,
+                                           backend_base_url,
                                            payment_activity->order_id,
                                            &payment_activity->amount,
                                            "failed to dispense product",
@@ -1586,7 +1687,7 @@ read_keyboard_command (void *cls)
     case 'c':
       if (GNUNET_NO == payment_activity->paid)
       {
-        mdb.cmd = &denyVend;
+        mdb.cmd = &cmd_deny_vend;
       }
       else
       {
@@ -1599,7 +1700,7 @@ read_keyboard_command (void *cls)
       break;
     case 'a':
       payment_activity->paid = GNUNET_YES;
-      mdb.cmd = &approveVend;
+      mdb.cmd = &cmd_approve_vend;
       run_mdb_event_loop ();
       break;
     case 'n':
@@ -1644,12 +1745,12 @@ read_keyboard_command (void *cls)
     if (((char) input) == products[i].key)
     {
       if ( (sold_out_enabled) &&
-           (products[i].sold_out) )
+           (GNUNET_YES == products[i].sold_out) )
       {
         GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                     "Product %s sold out, denying vend\n",
                     products[i].description);
-        mdb.cmd = &denyVend;
+        mdb.cmd = &cmd_reader_display_sold_out;
         run_mdb_event_loop ();
         start_read_keyboard ();
         return;
@@ -1664,6 +1765,11 @@ read_keyboard_command (void *cls)
   start_read_keyboard ();
 }
 
+/**
+ * @brief Read the state of the cancel button GPIO pin
+ *
+ * @param cls closure
+ */
 static void
 cancel_button_pressed (void *cls)
 {
@@ -1671,28 +1777,37 @@ cancel_button_pressed (void *cls)
   char value;
   cancelbutton_task = NULL;
 
-  read (cancelButton.cancelbuttonfd, &value, 1);
-  lseek (cancelButton.cancelbuttonfd, 0, SEEK_SET);
-  if ( '1' == value )
+  read (cancel_button.cancelbuttonfd, &value, 1);
+  lseek (cancel_button.cancelbuttonfd, 0, SEEK_SET);
+  /* This point should only be reached  when a order is pending, because
+   * the scheduler read file gets added in the function "launch_payment".
+   * But anyway safe check, else do nothing */
+  if (NULL != payment_activity)
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "Cancel button pressed, canceling current order\n");
-    if (GNUNET_NO == payment_activity->paid)
+    if ('1' == value)
     {
-      mdb.cmd = &denyVend;
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                  "Cancel button pressed, canceling current order\n");
+      if (GNUNET_NO == payment_activity->paid)
+      {
+        /* The current payment was not paid already, deny it */
+        mdb.cmd = &cmd_deny_vend;
+      }
+      else
+      {
+        /* The order was paid and if we know this, then it is also yielded,
+         * just end the current session */
+        mdb.cmd = &endSession;
+        mdb.session_running = GNUNET_NO;
+      }
+      run_mdb_event_loop ();
+      cleanup_payment (payment_activity);
+      payment_activity = NULL;
     }
     else
     {
-      mdb.cmd = &endSession;
-      mdb.session_running = GNUNET_NO;
+      start_read_cancel_button ();
     }
-    run_mdb_event_loop ();
-    cleanup_payment (payment_activity);
-    payment_activity = NULL;
-  }
-  else
-  {
-    start_read_cancel_button ();
   }
 }
 
@@ -1735,10 +1850,13 @@ start_read_keyboard ()
                                                   NULL);
 }
 
+/**
+ * @brief Wait for cancel button during payment activity
+ */
 static void
 start_read_cancel_button ()
 {
-  struct GNUNET_DISK_FileHandle fh = { cancelButton.cancelbuttonfd };
+  struct GNUNET_DISK_FileHandle fh = { cancel_button.cancelbuttonfd };
 
   GNUNET_assert (NULL == cancelbutton_task);
   cancelbutton_task = GNUNET_SCHEDULER_add_read_file (
@@ -1863,13 +1981,19 @@ write_mdb_command (void *cls)
 static void
 handle_ack ()
 {
-  if (&beginSession == mdb.last_cmd)
+  if (&cmd_begin_session == mdb.last_cmd)
     mdb.session_running = GNUNET_YES;
-  if (&denyVend == mdb.last_cmd)
+  if (&cmd_deny_vend == mdb.last_cmd)
   {
     mdb.session_running = GNUNET_NO;
     mdb.cmd = &endSession;
   }
+  if (&cmd_reader_display_sold_out == mdb.last_cmd)
+    mdb.cmd = &cmd_deny_vend;
+  if (&cmd_reader_display_internal_error == mdb.last_cmd)
+    mdb.cmd = &cmd_deny_vend;
+  if (&cmd_reader_display_backend_not_reachable == mdb.last_cmd)
+    mdb.cmd = &cmd_deny_vend;
   mdb.last_cmd = NULL;
   /* Cause the write-task to be re-scheduled now */
   if (NULL != mdb.wtask)
@@ -1891,6 +2015,8 @@ handle_command (const char *hex,
                 size_t hex_len)
 {
   unsigned int cmd;
+  unsigned int tmp = 0;
+  uint32_t chkSum;
 
   /* if the received command is 0 or not a multiple of 2 we cannot parse it */
   if (0 == hex_len)
@@ -1916,6 +2042,7 @@ handle_command (const char *hex,
     GNUNET_break_op (0);
     return;
   }
+
   /* parse the first byte (cmd) and the second byte (subcmd) */
   switch (cmd)
   {
@@ -1944,6 +2071,34 @@ handle_command (const char *hex,
       {
       case VMC_VEND_REQUEST:
         {
+
+          /* Calculate the checksum and check it */
+          chkSum = cmd;
+
+          for ( size_t offset = 1; offset < ((hex_len / 2)); offset++ ) {
+            chkSum += tmp;
+            if (1 != sscanf (hex + (2 * offset),
+                             "%2X",
+                             &tmp))
+            {
+              GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                          "Received non-HEX input `%.*s'\n",
+                          (int) hex_len,
+                          hex);
+              GNUNET_break_op (0);
+              return;
+            }
+          }
+          if ( ((uint8_t) (chkSum & 0xFF)) != tmp )
+          {
+            mdb.cmd = &cmd_reader_display_internal_error;
+            GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                        "Received command with wrong checksum `%.*s'\n",
+                        (int) hex_len,
+                        hex);
+            break;
+
+          }
           unsigned int product;
 
           GNUNET_break (GNUNET_YES == mdb.session_running);
@@ -1969,15 +2124,15 @@ handle_command (const char *hex,
             if (product == products[i].number)
             {
               GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                          "Product %u selected on NFC\n",
+                          "Product %u selected on MDB\n",
                           product);
               if ( (sold_out_enabled) &&
-                   (products[i].sold_out) )
+                   (GNUNET_YES == products[i].sold_out) )
               {
                 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                             "Product %s sold out, denying vend\n",
                             products[i].description);
-                mdb.cmd = &denyVend;
+                mdb.cmd = &cmd_reader_display_sold_out;
                 return;
               }
               payment_activity = launch_payment (&products[i]);
@@ -1986,7 +2141,7 @@ handle_command (const char *hex,
           GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                       "Unknown product %u selected on MDB, denying vend\n",
                       product);
-          mdb.cmd = &denyVend;
+          mdb.cmd = &cmd_deny_vend;
           break;
         }
       case VMC_VEND_SUCCESS:
@@ -2047,14 +2202,14 @@ handle_command (const char *hex,
         {
           GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                       "Received request for revalue via MDB\n");
-          mdb.cmd = &revalueApproved;
+          mdb.cmd = &cmd_revalue_approved;
           break;
         }
       case VMC_REVALUE_LIMIT_REQUEST:
         {
           GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                       "Received request for revalue limit amount via MDB\n");
-          mdb.cmd = &revalueAmount;
+          mdb.cmd = &cmd_revalue_amount;
           break;
         }
       default:
@@ -2067,14 +2222,60 @@ handle_command (const char *hex,
       break;
     }
   case VMC_CONF:
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "Received request for configuration via MDB\n");
-    mdb.cmd = &readerConfigData;
-    break;
+    {
+      unsigned int subcmd;
+
+      if (4 > hex_len)
+      {
+        GNUNET_break_op (0);
+        return;
+      }
+      if (1 != sscanf (&hex[2],
+                       "%2X",
+                       &subcmd))
+      {
+        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                    "Received non-HEX input `%.*s'\n",
+                    (int) hex_len - 2,
+                    &hex[2]);
+        GNUNET_break_op (0);
+        return;
+      }
+      switch (subcmd)
+      {
+      case VMC_READER_CONF:
+        {
+          GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                      "Received request for configuration via MDB\n");
+          mdb.cmd = &cmd_reader_config_data;
+          break;
+
+        }
+      case VMC_SETUP_MAX_MIN_PRICES:
+        {
+          GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                      "Received max and min prices via MDB\n");
+          break;
+        }
+      default:
+        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                    "Unknown MDB sub-command %X of command %X\n",
+                    subcmd,
+                    cmd);
+        break;
+      }
+      break;
+    }
   case VMC_POLL:
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Received POLL from MDB (ignored)\n");
     break;
+  case VMC_CMD_RESET:
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                  "Received RESET from MDB (ignored)\n");
+      break;
+    }
   case VMC_READER:
     {
       unsigned int subcmd;
@@ -2103,6 +2304,19 @@ handle_command (const char *hex,
           cleanup_payment (payment_activity);
           payment_activity = NULL;
         }
+        for (unsigned int i = 0; i < products_length; i++)
+        {
+          if ( (sold_out_enabled) &&
+               (0 != strcmp (products[i].description,
+                             "empty")) &&
+               (GNUNET_YES == products[i].sold_out) )
+          {
+            GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                        "Resetting sold out state of product %s\n",
+                        products[i].description);
+            products[i].sold_out = GNUNET_NO;
+          }
+        }
         break;
       case VMC_READER_ENABLE:
         GNUNET_log (GNUNET_ERROR_TYPE_INFO,
@@ -2110,7 +2324,7 @@ handle_command (const char *hex,
         mdb.session_running = GNUNET_NO;
         break;
       case VMC_READER_CANCEL:
-        mdb.cmd = &readerCancelled;
+        mdb.cmd = &cmd_reader_cancelled;
         mdb.session_running = GNUNET_NO;
         break;
       default:
@@ -2256,7 +2470,7 @@ run_mdb_event_loop ()
   {
     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                 "Begining MDB session\n");
-    mdb.cmd = &beginSession;
+    mdb.cmd = &cmd_begin_session;
   }
   /* start write task if he doesn't exist and if there is a cmd waiting to get sent */
   if ( (NULL == mdb.wtask) &&
@@ -2324,11 +2538,23 @@ read_products (void *cls,
                                "description");
     return;
   }
+  if (sold_out_enabled)
+  {
+    if (0 == strcmp (tmpProduct.description,
+                     "empty"))
+    {
+      tmpProduct.sold_out = GNUNET_YES;
+    }
+    else
+    {
+      tmpProduct.sold_out = GNUNET_NO;
+    }
+  }
   if (GNUNET_OK !=
-      TALER_config_get_denom (cls,
-                              section,
-                              "price",
-                              &tmpProduct.price))
+      TALER_config_get_amount (cls,
+                               section,
+                               "price",
+                               &tmpProduct.price))
   {
     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                section,
@@ -2520,7 +2746,7 @@ run (void *cls,
       GNUNET_CONFIGURATION_get_value_string (cfg,
                                              "taler-mdb",
                                              "backend-base-url",
-                                             &backendBaseUrl))
+                                             &backend_base_url))
   {
     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                "taler-mdb",
@@ -2553,7 +2779,7 @@ run (void *cls,
       GNUNET_CONFIGURATION_get_value_string (cfg,
                                              "taler-mdb",
                                              "fulfillment-url",
-                                             &fulfillmentUrl))
+                                             &fulfillment_url))
   {
     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                "taler-mdb",
@@ -2565,7 +2791,7 @@ run (void *cls,
       GNUNET_CONFIGURATION_get_value_string (cfg,
                                              "taler-mdb",
                                              "fulfillment-msg",
-                                             &fulfillmentMsg))
+                                             &fulfillment_msg))
   {
     GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
                                "taler-mdb",
@@ -2613,32 +2839,32 @@ run (void *cls,
                                             authorization));
 
   /* open gpio pin for cance button */
-  cancelButton.cancelbuttonfd = open ("/sys/class/gpio/export",
-                                      O_WRONLY);
-  if (0 > cancelButton.cancelbuttonfd)
+  cancel_button.cancelbuttonfd = open ("/sys/class/gpio/export",
+                                       O_WRONLY);
+  if (0 > cancel_button.cancelbuttonfd)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                 "Unable to open /gpio/export for cancel button\n");
   }
-  (void) write (cancelButton.cancelbuttonfd, "17", 2);
-  close (cancelButton.cancelbuttonfd);
+  (void) write (cancel_button.cancelbuttonfd, "23", 2);
+  close (cancel_button.cancelbuttonfd);
 
-  cancelButton.cancelbuttonfd = open ("/sys/class/gpio/gpio17/direction",
-                                      O_WRONLY);
-  if (0 > cancelButton.cancelbuttonfd)
+  cancel_button.cancelbuttonfd = open ("/sys/class/gpio/gpio23/direction",
+                                       O_WRONLY);
+  if (0 > cancel_button.cancelbuttonfd)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                "Unable to open /gpio/gpio17/direction for cancel button\n");
+                "Unable to open /gpio/gpio23/direction for cancel button\n");
   }
-  (void) write (cancelButton.cancelbuttonfd, "in", 2);
-  close (cancelButton.cancelbuttonfd);
+  (void) write (cancel_button.cancelbuttonfd, "in", 2);
+  close (cancel_button.cancelbuttonfd);
 
-  cancelButton.cancelbuttonfd = open ("/sys/class/gpio/gpio17/value",
-                                      O_RDONLY);
-  if (0 > cancelButton.cancelbuttonfd)
+  cancel_button.cancelbuttonfd = open ("/sys/class/gpio/gpio23/value",
+                                       O_RDONLY);
+  if (0 > cancel_button.cancelbuttonfd)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                "Unable to open /gpio/gpio17/value for cancel button\n");
+                "Unable to open /gpio/gpio23/value for cancel button\n");
   }
 
 
@@ -2832,35 +3058,57 @@ main (int argc,
     }
   }
   /* make the needed commands for the communication with the vending machine controller */
-  readerConfigData = setup_mdb_cmd ("Reader Config",
-                                    READER_CONFIG,
-                                    READER_FEATURE_LEVEL READER_COUNTRYCODE
-                                    READER_SCALE_FACTOR READER_DECIMAL_PLACES
-                                    READER_MAX_RESPONSE_TIME
-                                    READER_MISC_OPTIONS);
-  beginSession = setup_mdb_cmd ("Begin Session",
-                                READER_BEGIN_SESSION,
-                                READER_FUNDS_AVAILABLE);
-  approveVend = setup_mdb_cmd ("Approve Vend",
-                               READER_VEND_APPROVE,
-                               READER_VEND_AMOUNT);
-  readerCancelled = setup_mdb_cmd ("Confirm cancellation",
-                                   READER_CANCELLED,
-                                   NULL);
-  denyVend = setup_mdb_cmd ("Deny Vend",
-                            READER_VEND_DENIED,
-                            NULL);
+  cmd_reader_config_data = setup_mdb_cmd ("Reader Config",
+                                          READER_CONFIG,
+                                          READER_FEATURE_LEVEL
+                                          READER_COUNTRYCODE
+                                          READER_SCALE_FACTOR
+                                          READER_DECIMAL_PLACES
+                                          READER_MAX_RESPONSE_TIME
+                                          READER_MISC_OPTIONS);
+  cmd_begin_session = setup_mdb_cmd ("Begin Session",
+                                     READER_BEGIN_SESSION,
+                                     READER_FUNDS_AVAILABLE);
+  cmd_approve_vend = setup_mdb_cmd ("Approve Vend",
+                                    READER_VEND_APPROVE,
+                                    READER_VEND_AMOUNT);
+  cmd_reader_cancelled = setup_mdb_cmd ("Confirm cancellation",
+                                        READER_CANCELLED,
+                                        NULL);
+  cmd_deny_vend = setup_mdb_cmd ("Deny Vend",
+                                 READER_VEND_DENIED,
+                                 NULL);
   endSession = setup_mdb_cmd ("End Session",
                               READER_END_SESSION,
                               NULL);
-  revalueApproved = setup_mdb_cmd ("Reader Approve Revalue",
-                                   READER_REVALUE_APPROVED,
-                                   NULL);
+  cmd_revalue_approved = setup_mdb_cmd ("Reader Approve Revalue",
+                                        READER_REVALUE_APPROVED,
+                                        NULL);
 
-  revalueAmount = setup_mdb_cmd ("Send Revalue Limit Amount",
-                                 READER_REVALUE_LIMIT,
-                                 READER_REVALUE_LIMIT_AMOUNT);
+  cmd_revalue_amount = setup_mdb_cmd ("Send Revalue Limit Amount",
+                                      READER_REVALUE_LIMIT,
+                                      READER_REVALUE_LIMIT_AMOUNT);
+
+  cmd_reader_NACK = setup_mdb_cmd ("Reader NACK",
+                                   READER_NACK,
+                                   NULL);
 
+  cmd_reader_display_sold_out = setup_mdb_cmd ("Display Sold Out",
+                                               READER_DISPLAY_REQUEST,
+                                               READER_DISPLAY_REQUEST_TIME
+                                               READER_DISPLAY_SOLD_OUT);
+
+  cmd_reader_display_internal_error = setup_mdb_cmd (
+    "Display Communication Error",
+    READER_DISPLAY_REQUEST,
+    READER_DISPLAY_REQUEST_TIME
+    READER_DISPLAY_INTERNAL_ERROR);
+
+  cmd_reader_display_backend_not_reachable = setup_mdb_cmd (
+    "Display Backend not reachable",
+    READER_DISPLAY_REQUEST,
+    READER_DISPLAY_REQUEST_TIME
+    READER_DISPLAY_BACKEND_NOT_REACHABLE);
   ret = GNUNET_PROGRAM_run (argc,
                             argv,
                             "taler-mdb",
diff --git a/taler.conf b/taler.conf
index 8f382dd..7d925de 100644
--- a/taler.conf
+++ b/taler.conf
@@ -1,9 +1,9 @@
 [taler]
-currency = TESTKUDOS
+currency = EUR
 
 [taler-mdb]
-backend-base-url = http://backend.test.taler.net/
-backend-authorization = ApiKey sandbox
+backend-base-url = http://backend.euro.taler.net/
+backend-authorization = ApiKey Sandbox
 # taler url for success message (see taler documentation)
 fulfillment-url = taler://fulfillment-success
 # alternative url (see taler documentation)
@@ -22,149 +22,149 @@ FRAMEBUFFER_DEVICE = /dev/fb1
 FRAMEBUFFER_BACKLIGHT = /sys/class/backlight/soc:backlight/brightness
 
 #Products 
+#If sold out is enabled, products with description "empty" will be registered as sold out.
 
 #machine number 55
 [product-21]
 description = empty
-price = TESTKUDOS:0.1
+price = EUR:0.0
 number = 46
 
 #machine number 54
 [product-20]
 description = empty
-price = TESTKUDOS:0.1
+price = EUR:0.0
 number = 45
 
 #machine number 53
 [product-19]
-description = empty
-price = TESTKUDOS:0.1
+description = Hackerspace Passport
+price = EUR:1.0
 number = 44
 
 #machine number 52
 [product-18]
-description = empty
-price = TESTKUDOS:0.1
+description = T-Shirt M
+price = EUR:5.0
 number = 43
 
 #machine number 51
 [product-17]
-description = empty
-price = TESTKUDOS:0.1
+description = T-Shirt S
+price = EUR:5.0
 number = 42
 
 #machine number 50
 [product-16]
-description = empty
-price = TESTKUDOS:0.1
+description = Electronic Kit
+price = EUR:10.0
 number = 41
 
 #machine number 45
 [product-15]
 description = Snickers
-price = TESTKUDOS:0.1
+price = EUR:0.3
 number = 36
 
 #machine number 44
 [product-14]
-description = empty
-price = TESTKUDOS:0.1
+description = Electronic Kit
+price = EUR:7.0
 number = 35
 
 #machine number 43
 [product-13]
-description = Twix
-price = TESTKUDOS:0.1
+description = empty
+price = EUR:0.0
 key = d
 number = 34
 
 #machine number 42
 [product-12]
 description = Screwdriver
-price = TESTKUDOS:0.1
+price = EUR:15.0
 key = h
 number = 33
 
 #machine number 41
 [product-11]
-description = empty
-price = TESTKUDOS:0.1
+description = Twix
+price = EUR:0.3
 key = j
 number = 32
 
 #machine number 40
 [product-10]
 description = Mars
-price = TESTKUDOS:0.1
+price = EUR:0.3
 key = k
-number = 30
+number = 31
 
 #machine number 34
 [product-9]
-description = empty
-price = TESTKUDOS:0.1
+description = Book GRM - Brainfuck
+price = EUR:25.0
 key = l
 number = 25
 
 #machine number 30
 [product-8]
-description = Meter
-price = TESTKUDOS:0.1
+description = Ruler
+price = EUR:10.0
 key = w
 number = 21
 
 #machine number 25
 [product-7]
-description = empty
-price = TESTKUDOS:0.1
+description = NFC TAG 
+price = EUR:1.0
 key = e
 number = 16
 
 #machine number 24
 [product-6]
 description = Knive
-price = TESTKUDOS:0.1
+price = EUR:25.0
 key = r
 number = 15
 
 #machine number 23
 [product-5]
-description = empty
-price = TESTKUDOS:0.1
+description = Electronic Kit
+price = EUR:5.0
 key = t
 number = 14
 
 #machine number 22
 [product-4]
 description = empty
-price = TESTKUDOS:0.1
+price = EUR:0.0
 key = z
 number = 13
 
 #machine number 21
 [product-3]
 description = empty
-price = TESTKUDOS:0.1
+price = EUR:0.0
 key = u
 number = 12
 
 #machine number 20
 [product-2]
 description = Gummy bears
-price = TESTKUDOS:0.1
+price = EUR:0.3
 key = i
-number = 10
+number = 11
 
 #machine number 14
-[produt-1]
+[product-1]
 description = Sword
-price = TESTKUDOS:0.1
-key = o
-number = 5
+price = EUR:0.05
+number = 5 
 
 #machine number 10
 [product-0]
 description = Umbrella
-price = TESTKUDOS:0.1
+price = EUR:10.0
 key = p
 number = 1