add error display logic to main code

6 files changed, 245 insertions, 21 deletions

diff --git a/contrib/Makefile.am b/contrib/Makefile.am
index 2d6d46b..d0e7036 100644
--- a/contrib/Makefile.am
+++ b/contrib/Makefile.am
@@ -13,6 +13,7 @@ img_DATA = \
   png/maintenance.png
 
 bin_SCRIPTS = \
+  taler-mdb-ads.sh \
   taler-mdb-show.sh \
   taler-mdb-network-check.sh
 
diff --git a/contrib/taler-mdb-ads.sh b/contrib/taler-mdb-ads.sh
new file mode 100755
index 0000000..f097ba2
--- /dev/null
+++ b/contrib/taler-mdb-ads.sh
@@ -0,0 +1,56 @@
+#!/bin/bash
+
+set -eu
+
+function cleanup()
+{
+    taler-mdb-display -c "$CONF" -i
+    exit 0
+}
+
+trap cleanup EXIT
+
+CONF="$HOME/.config/taler.conf"
+
+# Parse command-line options
+while getopts ':c:h' OPTION; do
+    case "$OPTION" in
+        c)
+            CONF="$OPTARG"
+            ;;
+        h)
+            echo 'Supported options:'
+            # shellcheck disable=SC2016
+            echo '  -c $CONF     -- set configuration'
+            ;;
+        ?)
+            exit_fail "Unrecognized command line option"
+            ;;
+    esac
+done
+shift $((OPTIND - 1))
+
+taler-mdb-display -c "$CONF"
+
+FBDEV=$(taler-config -c "$CONF" -s taler-mdb -o FRAMEBUFFER_DEVICE)
+
+DATA_HOME=$(taler-config -c "$CONF" -s paths -o TALER_DATA_HOME)
+
+while true
+do
+    HOUR=$(date +%H)
+    if [[ HOUR -ge 8 && HOUR -lt 22 ]]
+    then
+        taler-mdb-display -c "$CONF"
+        for AD in $(ls "${DATA_HOME}/ads/*" | shuf)
+        do
+            DELAY=$(echo "$AD" | awk -F'[-.]' '{print $(NF-1)}')
+            fbi -d "$FBDEV" -a -m "768x576-75" -vt 2 -nocomments -noverbose "$AD"
+            sleep "$DELAY"
+        done
+        taler-mdb-display -c "$CONF" -i
+    else
+        # Night time, save power!
+        sleep 600
+    fi
+done
diff --git a/contrib/taler-mdb-show.sh b/contrib/taler-mdb-show.sh
index 7073b9f..c06a089 100644..100755
--- a/contrib/taler-mdb-show.sh
+++ b/contrib/taler-mdb-show.sh
@@ -34,7 +34,9 @@ taler-mdb-display -c "$CONF"
 
 FBDEV=$(taler-config -c "$CONF" -s taler-mdb -o FRAMEBUFFER_DEVICE)
 
-fbi -d "$FBDEV" -a -m "768x576-75" -vt 2 -nocomments -noverbose "$1.png"
+DATA_HOME=$(taler-config -c "$CONF" -s paths -o TALER_DATA_HOME)
+
+fbi -d "$FBDEV" -a -m "768x576-75" -vt 2 -nocomments -noverbose "${DATA_HOME}/mdb/$1.png"
 
 while true
 do
diff --git a/debian/etc/taler-mdb.conf b/debian/etc/taler-mdb.conf
index 94dfcdd..561256b 100644
--- a/debian/etc/taler-mdb.conf
+++ b/debian/etc/taler-mdb.conf
@@ -7,6 +7,9 @@ BACKEND_BASE_URL = http://backend.demo.taler.net/
 # Secret key to talk to *all* instances we use.
 BACKEND_AUTHORIZATION = "Bearer secret-token:sandbox"
 
+# Program to use to show ads.
+ADVERTISEMENT_COMMAND = taler-mdb-ads.sh -c /etc/taler-mdb.conf
+
 # Message to diplay after purchase is completed,
 FULFILLMENT_MSG = Enjoy your ${PRODUCT_DESCRIPTION}
 
diff --git a/src/.gitignore b/src/.gitignore
index f66074a..c6b6bf5 100644
--- a/src/.gitignore
+++ b/src/.gitignore
@@ -1,3 +1,4 @@
 *.o
 taler-nfc
 taler-coin-acceptor
+taler-mdb-display
diff --git a/src/taler-mdb.c b/src/taler-mdb.c
index 431a505..3acd633 100644
--- a/src/taler-mdb.c
+++ b/src/taler-mdb.c
@@ -84,6 +84,12 @@ along with
     GNUNET_TIME_UNIT_MINUTES, 2)
 
 /**
+ * How long to show a transient error.
+ */
+#define ERR_DELAY GNUNET_TIME_relative_multiply ( \
+    GNUNET_TIME_UNIT_SECONDS, 30)
+
+/**
  * How long could it take at most for us to notify the Taler merchant
  * backend to grant a refund to a user if dispensing the product
  * failed? (Very conservative value here, for vending machines brewing
@@ -634,16 +640,33 @@ static struct GNUNET_SCHEDULER_Task *keyboard_task;
 static struct GNUNET_SCHEDULER_Task *cancelbutton_task;
 
 /**
+ * Task to stop showing transient errors.
+ */
+static struct GNUNET_SCHEDULER_Task *err_stop_task;
+
+/**
  * Handle to the process showing messages/advertisements
  * while we are inactive.
  */
 static struct GNUNET_OS_Process *adv_child;
 
 /**
- * Name of the process to run when advertising is enabled.
+ * Handle to the process showing error messages
+ * while we have one.
+ */
+static struct GNUNET_OS_Process *err_child;
+
+/**
+ * Command to run when advertising is enabled.
+ * Can be NULL.
+ */
+static char *adv_process_command;
+
+/**
+ * Command to run when advertising is enabled.
  * Can be NULL.
  */
-static char *adv_process_filename;
+static char *err_process_command;
 
 /**
  * Taler Backend url read from configuration file
@@ -817,6 +840,135 @@ static struct Display qrDisplay;
 
 
 /**
+ * Start process using the @a command command-line.
+ *
+ * @param command command to run
+ * @param ... extra arguments to pass
+ * @return process handle, NULL on failure
+ */
+static struct GNUNET_OS_Process *
+start_command (const char *command,
+               ...)
+{
+  char **argv = NULL;
+  unsigned int argc = 0;
+  char *cpy = GNUNET_strdup (adv_process_command);
+  struct GNUNET_OS_Process *ret;
+  va_list ap;
+  const char *arg;
+
+  for (const char *tok = strtok (cpy, " ");
+       NULL != tok;
+       tok = strtok (NULL, " "))
+  {
+    GNUNET_array_append (argv,
+                         argc,
+                         GNUNET_strdup (tok));
+  }
+  va_start (ap,
+            command);
+  while (NULL != (arg = va_arg (ap,
+                                const char *)))
+  {
+    GNUNET_array_append (argv,
+                         argc,
+                         GNUNET_strdup (arg));
+  }
+  va_end (ap);
+  GNUNET_array_append (argv,
+                       argc,
+                       NULL);
+  ret = GNUNET_OS_start_process_vap (GNUNET_OS_INHERIT_STD_NONE,
+                                     NULL,
+                                     NULL,
+                                     NULL,
+                                     argv[0],
+                                     argv);
+  for (unsigned int i = 0; i<argc; i++)
+    GNUNET_free (argv[i]);
+  GNUNET_array_grow (argv,
+                     argc,
+                     0);
+  GNUNET_free (cpy);
+  return ret;
+}
+
+
+/**
+ * Stop the process showing an error.
+ */
+static void
+hide_error (void)
+{
+  if (NULL == err_child)
+    return;
+  if (NULL != err_stop_task)
+  {
+    GNUNET_SCHEDULER_cancel (err_stop_task);
+    err_stop_task = NULL;
+  }
+  GNUNET_break (0 ==
+                GNUNET_OS_process_kill (err_child,
+                                        SIGTERM));
+  GNUNET_break (GNUNET_OK ==
+                GNUNET_OS_process_wait (err_child));
+  GNUNET_OS_process_destroy (err_child);
+  err_child = NULL;
+}
+
+
+/**
+ * Show an error using the respective error process
+ * command.
+ *
+ * @param err_type type of the error to pass to the command
+ */
+static void
+show_error (const char *err_type)
+{
+  hide_error (); /* just to be sure */
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Showing error `%s'\n",
+              err_type);
+  if (NULL == err_process_command)
+  {
+    return;
+  }
+  err_child = start_command (err_process_command,
+                             err_type,
+                             NULL);
+}
+
+
+/**
+ * Task to stop the process showing an error.
+ *
+ * @param cls NULL
+ */
+static void
+do_hide_error (void *cls)
+{
+  err_stop_task = NULL;
+  hide_error ();
+}
+
+
+/**
+ * Briefly show a temporary error.
+ *
+ * @param err_type error to show
+ */
+static void
+temporary_error (const char *err_type)
+{
+  show_error (err_type);
+  err_stop_task = GNUNET_SCHEDULER_add_delayed (ERR_DELAY,
+                                                &do_hide_error,
+                                                NULL);
+}
+
+
+/**
  * Stop the advertising process.
  */
 static void
@@ -841,15 +993,10 @@ static void
 start_advertising (void)
 {
   stop_advertising (); /* just to be sure */
-  if (NULL == adv_process_filename)
+  if (NULL == adv_process_command)
     return;
-  adv_child = GNUNET_OS_start_process (GNUNET_OS_INHERIT_STD_NONE,
-                                       NULL,
-                                       NULL,
-                                       NULL,
-                                       adv_process_filename,
-                                       adv_process_filename,
-                                       NULL);
+  adv_child = start_command (adv_process_command,
+                             NULL);
 }
 
 
@@ -874,6 +1021,7 @@ show_qrcode (const char *uri)
   const char *dddash;
 
   stop_advertising ();
+  hide_error ();
   if (0 > qrDisplay.devicefd)
     return; /* no display, no dice */
   /* find the fourth '/' in the payto://pay/hostname/-uri */
@@ -1149,6 +1297,7 @@ mdb_shutdown (void)
     GNUNET_SCHEDULER_cancel (mdb.wtask);
     mdb.wtask = NULL;
   }
+  hide_error ();
   stop_advertising ();
   if (disable_mdb)
     return;
@@ -1385,8 +1534,12 @@ wallet_select_aid (void *cls)
 
   pa->task = NULL;
   /* append the taler wallet aid to the select file command */
-  memcpy (message, select_file, sizeof (select_file));
-  memcpy (&message[sizeof (select_file)], taler_aid, sizeof (taler_aid));
+  memcpy (message,
+          select_file,
+          sizeof (select_file));
+  memcpy (&message[sizeof (select_file)],
+          taler_aid,
+          sizeof (taler_aid));
 
   /* send the select file command via nfc */
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
@@ -1567,6 +1720,7 @@ check_payment_cb (void *cls,
                 hr->http_status,
                 (int) hr->ec);
     mdb.cmd = &cmd_reader_display_backend_not_reachable;
+    temporary_error ("backend-unexpected-failure");
     run_mdb_event_loop ();
     cleanup_payment (pa);
     GNUNET_assert (payment_activity == pa);
@@ -1575,9 +1729,8 @@ check_payment_cb (void *cls,
   }
 
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Backend request to /check-payment returned: %u/%d\n",
-              hr->http_status,
-              (int) osr->details.ok.status);
+              "Backend request to /check-payment returned: %u\n",
+              hr->http_status);
   if ( (MHD_HTTP_OK == hr->http_status) &&
        (TALER_MERCHANT_OSC_PAID == osr->details.ok.status) )
   {
@@ -1674,6 +1827,7 @@ proposal_cb (void *cls,
     json_dumpf (por->hr.reply,
                 stderr,
                 0);
+    temporary_error ("backend-temporary-failure");
     mdb.cmd = &cmd_reader_display_backend_not_reachable;
     run_mdb_event_loop ();
     cleanup_payment (pa);
@@ -1832,6 +1986,7 @@ launch_payment (struct Product *product)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "TALER_MERCHANT_order_put failed (out of memory?)\n");
+    temporary_error ("internal-failure");
     cleanup_payment (pa);
     return NULL;
   }
@@ -2429,8 +2584,8 @@ handle_command (const char *hex,
                         "Received command with wrong checksum `%.*s'\n",
                         (int) hex_len,
                         hex);
+            temporary_error ("err-num-read-fail");
             break;
-
           }
           unsigned int product;
 
@@ -2466,6 +2621,7 @@ handle_command (const char *hex,
                             "Product %s sold out, denying vend\n",
                             products[i].description);
                 mdb.cmd = &cmd_reader_display_sold_out;
+                temporary_error ("err-sold-out");
                 return;
               }
               payment_activity = launch_payment (&products[i]);
@@ -2476,6 +2632,7 @@ handle_command (const char *hex,
           GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                       "Unknown product %u selected on MDB, denying vend\n",
                       product);
+          temporary_error ("unknown-product");
           mdb.cmd = &cmd_deny_vend;
           break;
         }
@@ -3203,10 +3360,14 @@ run (void *cls,
     global_ret = EXIT_FAILURE;
     return;
   }
-  (void) GNUNET_CONFIGURATION_get_value_filename (cfg,
-                                                  "taler-mdb",
-                                                  "ADVERTISEMENT_BINARY",
-                                                  &adv_process_filename);
+  (void) GNUNET_CONFIGURATION_get_value_string (cfg,
+                                                "taler-mdb",
+                                                "ADVERTISEMENT_COMMAND",
+                                                &adv_process_command);
+  (void) GNUNET_CONFIGURATION_get_value_string (cfg,
+                                                "taler-mdb",
+                                                "FAIL_COMMAND",
+                                                &err_process_command);
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_string (cfg,
                                              "taler-mdb",