Changing configuration structure to enable multiple accounts.

This change enables using multiple wire plugins at the same time.
Also, we now distinguish between the wire plugin (i.e. EBICS or
taler_bank) and the wire method (i.e. SEPA or x-taler-bank) that
the wire plugin is implementing.  The "taler-bank" wire method
was renamed from "test" to "x-taler-bank".

This also changes the format of the /wire response of the exchange,
as we now need to return multiple accounts.  Note that wire fees
are specified per wire method, not per wire account.

taler-exchange-keyup now automatically signs all of the /wire
responses in the location specified by the configuration.

Account identification in wire plugins was changed to use
payto://-URLs instead of method-specific JSON fields.  Signing
and validation of /wire responses was moved from each wire
plugin to a generic validation method in libtalerutil (crypto)
or libtalerjson (for JSON-formatted inputs).
Convenience methods were added to generate JSON for wire accounts
(salting, signing).

Various section and option names were adjusted to streamline the
configuration and make it more consistent overall.  Documentation
was updated as well.

1 files changed, 147 insertions, 56 deletions

diff --git a/src/exchange/taler-exchange-wirewatch.c b/src/exchange/taler-exchange-wirewatch.c
index e0985366d..cabfac7f4 100644
--- a/src/exchange/taler-exchange-wirewatch.c
+++ b/src/exchange/taler-exchange-wirewatch.c
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2016, 2017 GNUnet e.V.
+  Copyright (C) 2016, 2017, 2018 Taler Systems SA
 
   TALER is free software; you can redistribute it and/or modify it under the
   terms of the GNU Affero General Public License as published by the Free Software
@@ -54,9 +54,58 @@ struct RejectContext
 
 
 /**
- * Handle to the plugin.
+ * Information we keep for each supported account.
  */
-static struct TALER_WIRE_Plugin *wire_plugin;
+struct WireAccount
+{
+  /**
+   * Accounts are kept in a DLL.
+   */
+  struct WireAccount *next;
+
+  /**
+   * Plugins are kept in a DLL.
+   */
+  struct WireAccount *prev;
+
+  /**
+   * Handle to the plugin.
+   */
+  struct TALER_WIRE_Plugin *wire_plugin;
+
+  /**
+   * Name of the section that configures this account.
+   */
+  char *section_name;
+
+  /**
+   * Are we running from scratch and should re-process all transactions
+   * for this account?
+   */
+  int reset_mode;
+
+  /**
+   * Until when is processing this wire plugin delayed?
+   */
+  struct GNUNET_TIME_Absolute delayed_until;
+
+};
+
+
+/**
+ * Head of list of loaded wire plugins.
+ */
+static struct WireAccount *wa_head;
+
+/**
+ * Tail of list of loaded wire plugins.
+ */
+static struct WireAccount *wa_tail;
+
+/**
+ * Wire plugin we are currently using.
+ */
+static struct WireAccount *wa_pos;
 
 /**
  * Which currency is used by this exchange?
@@ -91,11 +140,6 @@ static void *last_row_off;
 static size_t last_row_off_size;
 
 /**
- * Which wire plugin are we watching?
- */
-static char *type;
-
-/**
  * Should we delay the next request to the wire plugin a bit?
  */
 static int delay;
@@ -134,6 +178,8 @@ static struct TALER_WIRE_RejectHandle *rt;
 static void
 shutdown_task (void *cls)
 {
+  struct WireAccount *wa;
+
   if (NULL != task)
   {
     GNUNET_SCHEDULER_cancel (task);
@@ -141,23 +187,31 @@ shutdown_task (void *cls)
   }
   if (NULL != hh)
   {
-    wire_plugin->get_history_cancel (wire_plugin->cls,
-				     hh);
+    wa_pos->wire_plugin->get_history_cancel (wa_pos->wire_plugin->cls,
+                                             hh);
     hh = NULL;
   }
   if (NULL != rt)
   {
     char *wtid_s;
 
-    wtid_s = wire_plugin->reject_transfer_cancel (wire_plugin->cls,
-                                                  rt);
+    wtid_s = wa_pos->wire_plugin->reject_transfer_cancel (wa_pos->wire_plugin->cls,
+                                                          rt);
     rt = NULL;
     GNUNET_free (wtid_s);
   }
   TALER_EXCHANGEDB_plugin_unload (db_plugin);
   db_plugin = NULL;
-  TALER_WIRE_plugin_unload (wire_plugin);
-  wire_plugin = NULL;
+  while (NULL != (wa = wa_head))
+  {
+    GNUNET_CONTAINER_DLL_remove (wa_head,
+                                 wa_tail,
+                                 wa);
+    TALER_WIRE_plugin_unload (wa->wire_plugin);
+    GNUNET_free (wa->section_name);
+    GNUNET_free (wa);
+  }
+  wa_pos = NULL;
   GNUNET_free_non_null (last_row_off);
   last_row_off = NULL;
   last_row_off_size = 0;
@@ -165,6 +219,41 @@ shutdown_task (void *cls)
 
 
 /**
+ * Function called with information about a wire account.  Adds the
+ * account to our list (if it is enabled and we can load the plugin).
+ *
+ * @param cls closure, NULL
+ * @param ai account information
+ */
+static void
+add_account_cb (void *cls,
+                const struct TALER_EXCHANGEDB_AccountInfo *ai)
+{
+  struct WireAccount *wa;
+
+  (void) cls;
+  if (GNUNET_YES != ai->credit_enabled)
+    return; /* not enabled for us, skip */
+  wa = GNUNET_new (struct WireAccount);
+  wa->reset_mode = reset_mode;
+  wa->wire_plugin = TALER_WIRE_plugin_load (cfg,
+                                            ai->plugin_name);
+  if (NULL == wa->wire_plugin)
+  {
+    fprintf (stderr,
+             "Failed to load wire plugin for `%s'\n",
+             ai->plugin_name);
+    GNUNET_free (wa);
+    return;
+  }
+  wa->section_name = GNUNET_strdup (ai->section_name);
+  GNUNET_CONTAINER_DLL_insert (wa_head,
+                               wa_tail,
+                               wa);
+}
+
+
+/**
  * Parse configuration parameters for the exchange server into the
  * corresponding global variables.
  *
@@ -173,12 +262,6 @@ shutdown_task (void *cls)
 static int
 exchange_serve_process_config ()
 {
-  if (NULL == type)
-  {
-    fprintf (stderr,
-             "Option `-t' to specify wire plugin is mandatory.\n");
-    return GNUNET_SYSERR;
-  }
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_string (cfg,
                                              "taler",
@@ -206,17 +289,16 @@ exchange_serve_process_config ()
              "Failed to initialize DB subsystem\n");
     return GNUNET_SYSERR;
   }
-  if (NULL ==
-      (wire_plugin = TALER_WIRE_plugin_load (cfg,
-					     type)))
+  TALER_EXCHANGEDB_find_accounts (cfg,
+                                  &add_account_cb,
+                                  NULL);
+  if (NULL == wa_head)
   {
     fprintf (stderr,
-             "Failed to load wire plugin for `%s'\n",
-             type);
+             "No wire accounts configured for credit!\n");
     TALER_EXCHANGEDB_plugin_unload (db_plugin);
     return GNUNET_SYSERR;
   }
-
   return GNUNET_OK;
 }
 
@@ -292,12 +374,11 @@ history_cb (void *cls,
   struct TALER_ReservePublicKeyP reserve_pub;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Got history callback, direction %u!\n", (unsigned int) dir);
-
+              "Got history callback, direction %u!\n",
+              (unsigned int) dir);
   if (TALER_BANK_DIRECTION_NONE == dir)
   {
     hh = NULL;
-
     if (TALER_EC_NONE != ec)
     {
       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
@@ -309,18 +390,27 @@ history_cb (void *cls,
     qs = db_plugin->commit (db_plugin->cls,
 			    session);
     if ( (GNUNET_YES == delay) &&
-         (test_mode) )
+         (test_mode) &&
+         (NULL == wa_pos->next) )
     {
       GNUNET_SCHEDULER_shutdown ();
       return GNUNET_OK;
     }
     if (GNUNET_YES == delay)
-      task = GNUNET_SCHEDULER_add_delayed (DELAY,
-					   &find_transfers,
-					   NULL);
-    else
-      task = GNUNET_SCHEDULER_add_now (&find_transfers,
-				       NULL);
+    {
+      wa_pos->delayed_until
+        = GNUNET_TIME_relative_to_absolute (DELAY);
+      GNUNET_free_non_null (last_row_off);
+      last_row_off = NULL;
+      last_row_off_size = 0;
+      wa_pos = wa_pos->next;
+      if (NULL == wa_pos)
+        wa_pos = wa_head;
+      GNUNET_assert (NULL != wa_pos);
+    }
+    task = GNUNET_SCHEDULER_add_at (wa_pos->delayed_until,
+                                    &find_transfers,
+                                    NULL);
     return GNUNET_OK; /* will be ignored anyway */
   }
   if (NULL != details->wtid_s)
@@ -344,11 +434,12 @@ history_cb (void *cls,
     rtc = GNUNET_new (struct RejectContext);
     rtc->session = session;
     rtc->wtid_s = GNUNET_strdup (details->wtid_s);
-    rt = wire_plugin->reject_transfer (wire_plugin->cls,
-                                       row_off,
-                                       row_off_size,
-                                       &reject_cb,
-                                       rtc);
+    rt = wa_pos->wire_plugin->reject_transfer (wa_pos->wire_plugin->cls,
+                                               wa_pos->section_name,
+                                               row_off,
+                                               row_off_size,
+                                               &reject_cb,
+                                               rtc);
     return GNUNET_SYSERR; /* will continue later... */
   }
 
@@ -366,7 +457,8 @@ history_cb (void *cls,
 				      &reserve_pub,
 				      &details->amount,
 				      details->execution_date,
-				      details->account_details,
+				      details->account_url,
+                                      wa_pos->section_name,
 				      row_off,
 				      row_off_size);
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
@@ -434,10 +526,11 @@ find_transfers (void *cls)
     GNUNET_SCHEDULER_shutdown ();
     return;
   }
-  if (! reset_mode)
+  if (! wa_pos->reset_mode)
   {
     qs = db_plugin->get_latest_reserve_in_reference (db_plugin->cls,
                                                      session,
+                                                     wa_pos->section_name,
                                                      &last_row_off,
                                                      &last_row_off_size);
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
@@ -456,17 +549,19 @@ find_transfers (void *cls)
       return;
     }
   }
+  wa_pos->reset_mode = GNUNET_NO;
   GNUNET_assert ( (NULL == last_row_off) ||
                   ( (NULL != last_row_off) &&
                     (0 != last_row_off_size) ) );
   delay = GNUNET_YES;
-  hh = wire_plugin->get_history (wire_plugin->cls,
-				 TALER_BANK_DIRECTION_CREDIT,
-				 last_row_off,
-				 last_row_off_size,
-				 1024,
-				 &history_cb,
-				 session);
+  hh = wa_pos->wire_plugin->get_history (wa_pos->wire_plugin->cls,
+                                         wa_pos->section_name,
+                                         TALER_BANK_DIRECTION_CREDIT,
+                                         last_row_off,
+                                         last_row_off_size,
+                                         1024,
+                                         &history_cb,
+                                         session);
   if (NULL == hh)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
@@ -501,7 +596,8 @@ run (void *cls,
     global_ret = 1;
     return;
   }
-
+  wa_pos = wa_head;
+  GNUNET_assert (NULL != wa_pos);
   task = GNUNET_SCHEDULER_add_now (&find_transfers,
                                    NULL);
   GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
@@ -521,11 +617,6 @@ main (int argc,
       char *const *argv)
 {
   struct GNUNET_GETOPT_CommandLineOption options[] = {
-    GNUNET_GETOPT_option_string ('t',
-				 "type",
-				 "PLUGINNAME",
-				 "which wire plugin to use",
-				 &type),
     GNUNET_GETOPT_option_flag ('T',
 			       "test",
 			       "run in test mode and exit when idle",