starting to implement taler-exchange-wirewatch

1 files changed, 372 insertions, 0 deletions

diff --git a/src/exchange/taler-exchange-wirewatch.c b/src/exchange/taler-exchange-wirewatch.c
new file mode 100644
index 000000000..9c582dd56
--- /dev/null
+++ b/src/exchange/taler-exchange-wirewatch.c
@@ -0,0 +1,372 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2016, 2017 GNUnet e.V.
+
+  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
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+/**
+ * @file taler-exchange-wirewatch.c
+ * @brief Process that watches for wire transfers to the exchange's bank account
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include <jansson.h>
+#include <pthread.h>
+#include <microhttpd.h>
+#include "taler_exchangedb_lib.h"
+#include "taler_exchangedb_plugin.h"
+#include "taler_json_lib.h"
+#include "taler_wire_lib.h"
+
+/**
+ * How long do we sleep before trying again if there
+ * are no transactions returned by the wire plugin?
+ */
+#define DELAY GNUNET_TIME_UNIT_SECONDS
+
+
+/**
+ * Handle to the plugin.
+ */
+static struct TALER_WIRE_Plugin *wire_plugin;
+  
+/**
+ * Which currency is used by this exchange?
+ */
+static char *exchange_currency_string;
+
+/**
+ * The exchange's configuration (global)
+ */
+static const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+/**
+ * Our DB plugin.
+ */
+static struct TALER_EXCHANGEDB_Plugin *db_plugin;
+
+/**
+ * Value to return from main(). #GNUNET_OK on success, #GNUNET_SYSERR
+ * on serious errors.
+ */
+static int global_ret;
+
+/**
+ * Encoded offset in the wire transfer list that we 
+ * processed last.
+ */
+static void *last_row_off;
+
+/**
+ * Number of bytes in #last_row_off.
+ */
+static size_t last_row_off_size;
+
+/**
+ * Encoded offset in the wire transfer list from where
+ * to start the next query with the bank.
+ */
+static void *start_off;
+
+/**
+ * Number of bytes in #start_off.
+ */
+static size_t start_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;
+
+/**
+ * Next task to run, if any.
+ */
+static struct GNUNET_SCHEDULER_Task *task;
+
+/**
+ * Active request for history.
+ */
+static struct TALER_WIRE_HistoryHandle *hh;
+
+
+/**
+ * We're being aborted with CTRL-C (or SIGTERM). Shut down.
+ *
+ * @param cls closure
+ */
+static void
+shutdown_task (void *cls)
+{
+  if (NULL != task)
+  {
+    GNUNET_SCHEDULER_cancel (task);
+    task = NULL;
+  }
+  if (NULL != hh)
+  {
+    wire_plugin->get_history_cancel (wire_plugin->cls,
+				     hh);
+    hh = NULL;
+  }
+  TALER_EXCHANGEDB_plugin_unload (db_plugin);
+  db_plugin = NULL;
+  TALER_WIRE_plugin_unload (wire_plugin);
+  wire_plugin = NULL;
+  GNUNET_free_non_null (start_off);
+  start_off = NULL;
+}
+
+
+/**
+ * Parse configuration parameters for the exchange server into the
+ * corresponding global variables.
+ *
+ * @return #GNUNET_OK on success
+ */
+static int
+exchange_serve_process_config ()
+{
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_string (cfg,
+                                             "taler",
+                                             "currency",
+                                             &exchange_currency_string))
+  {
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+                               "taler",
+                               "currency");
+    return GNUNET_SYSERR;
+  }
+  if (strlen (exchange_currency_string) >= TALER_CURRENCY_LEN)
+  {
+    fprintf (stderr,
+             "Currency `%s' longer than the allowed limit of %u characters.",
+             exchange_currency_string,
+             (unsigned int) TALER_CURRENCY_LEN);
+    return GNUNET_SYSERR;
+  }
+
+  if (NULL ==
+      (db_plugin = TALER_EXCHANGEDB_plugin_load (cfg)))
+  {
+    fprintf (stderr,
+             "Failed to initialize DB subsystem\n");
+    return GNUNET_SYSERR;
+  }
+
+  if (NULL ==
+      (wire_plugin = TALER_WIRE_plugin_load (cfg,
+					     type)))
+  {
+    fprintf (stderr,
+             "Failed to load wire plugin for `%s'\n",
+             type);
+    TALER_EXCHANGEDB_plugin_unload (db_plugin);
+    return GNUNET_SYSERR;
+  }
+  
+  return GNUNET_OK;
+}
+
+
+/**
+ * Query for incoming wire transfers.
+ *
+ * @param cls NULL
+ */
+static void
+find_transfers (void *cls);
+
+
+/**
+ * Callbacks of this type are used to serve the result of asking
+ * the bank for the transaction history.
+ *
+ * @param cls closure with the `struct TALER_EXCHANGEDB_Session *`
+ * @param dir direction of the transfer
+ * @param row_off identification of the position at which we are querying
+ * @param row_off_size number of bytes in @a row_off
+ * @param details details about the wire transfer
+ */
+static void
+history_cb (void *cls,
+	    enum TALER_BANK_Direction dir,
+	    const void *row_off,
+	    size_t row_off_size,
+	    const struct TALER_BANK_TransferDetails *details)
+{
+  struct TALER_EXCHANGEDB_Session *session = cls;
+
+  // TODO: store to DB...
+  if (TALER_BANK_DIRECTION_NONE == dir)
+  {
+    int ret;
+
+    hh = NULL;
+    ret = db_plugin->commit (db_plugin->cls,
+			     session);
+    if (GNUNET_OK == ret)
+    {
+      GNUNET_free_non_null (start_off);
+      start_off = last_row_off;
+      start_off_size = last_row_off_size;
+    }
+    if (GNUNET_YES == delay)
+      task = GNUNET_SCHEDULER_add_delayed (DELAY,
+					   &find_transfers,
+					   NULL);
+    else
+      task = GNUNET_SCHEDULER_add_now (&find_transfers,
+				       NULL);
+    return;
+  }
+  
+  if (last_row_off_size != row_off_size)
+  {
+    GNUNET_free_non_null (last_row_off);
+    last_row_off = GNUNET_malloc (row_off_size);
+  }
+  memcpy (last_row_off,
+	  row_off,
+	  row_off_size);
+}
+
+
+/**
+ * Query for incoming wire transfers.
+ *
+ * @param cls NULL
+ */
+static void
+find_transfers (void *cls)
+{
+  struct TALER_EXCHANGEDB_Session *session;
+  
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Checking for incoming wire transfers\n");
+
+  if (NULL == (session = db_plugin->get_session (db_plugin->cls)))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to obtain database session!\n");
+    global_ret = GNUNET_SYSERR;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
+  if (GNUNET_OK !=
+      db_plugin->start (db_plugin->cls,
+                        session))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to start database transaction!\n");
+    global_ret = GNUNET_SYSERR;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
+  delay = GNUNET_YES;
+  hh = wire_plugin->get_history (wire_plugin->cls,
+				 TALER_BANK_DIRECTION_CREDIT,
+				 start_off,
+				 start_off_size,
+				 1024,
+				 &history_cb,
+				 session);
+  if (NULL == hh)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to start request for account history!\n");
+    db_plugin->rollback (db_plugin->cls,
+                         session);
+    global_ret = GNUNET_SYSERR;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
+  /* FIXME: write last_off! */
+}
+
+
+/**
+ * First task.
+ *
+ * @param cls closure, NULL
+ * @param args remaining command-line arguments
+ * @param cfgfile name of the configuration file used (for saving, can be NULL!)
+ * @param c configuration
+ */
+static void
+run (void *cls,
+     char *const *args,
+     const char *cfgfile,
+     const struct GNUNET_CONFIGURATION_Handle *c)
+{
+  cfg = c;
+  if (GNUNET_OK !=
+      exchange_serve_process_config ())
+  {
+    global_ret = 1;
+    return;
+  }
+  
+  task = GNUNET_SCHEDULER_add_now (&find_transfers,
+                                   NULL);
+  GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
+                                 cls);
+}
+
+
+/**
+ * The main function of taler-exchange-wirewatch
+ *
+ * @param argc number of arguments from the command line
+ * @param argv command line arguments
+ * @return 0 ok, 1 on error
+ */
+int
+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_version (VERSION "-" VCS_VERSION),
+    GNUNET_GETOPT_OPTION_END
+  };
+
+  if (GNUNET_OK !=
+      GNUNET_STRINGS_get_utf8_args (argc, argv,
+				    &argc, &argv))
+    return 2;
+  if (GNUNET_OK !=
+      GNUNET_PROGRAM_run (argc, argv,
+                          "taler-exchange-wirewatch",
+                          gettext_noop ("background process that watches for incomming wire transfers from customers"),
+                          options,
+                          &run, NULL))
+  {
+    GNUNET_free ((void*) argv);
+    return 1;
+  }
+  GNUNET_free ((void*) argv);
+  return global_ret;
+}
+
+/* end of taler-exchange-wirewatch.c */