start with KYC support in DB

src/exchange/taler-exchange-httpd.c

@@ -1075,6 +1075,48 @@ handle_mhd_request (void *cls,
 }
 
 
+/**
+ * Load general KYC configuration parameters for the exchange server into the
+ * #TEH_kyc_config variable.
+ *
+ * @return #GNUNET_OK on success
+ */
+static enum GNUNET_GenericReturnValue
+parse_kyc_settings (void)
+{
+  if (GNUNET_OK !=
+      GNUNET_CONFIGURATION_get_value_time (TEH_cfg,
+                                           "exchange",
+                                           "KYC_WITHDRAW_PERIOD",
+                                           &TEH_kyc_config.withdraw_period))
+  {
+    GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                               "exchange",
+                               "KYC_WITHDRAW_PERIOD",
+                               "valid relative time expected");
+    return GNUNET_SYSERR;
+  }
+  if (GNUNET_TIME_relative_is_zero (TEH_kyc_config.withdraw_period))
+    return GNUNET_OK;
+  if (GNUNET_OK !=
+      TALER_config_get_amount (TEH_cfg,
+                               "exchange",
+                               "KYC_WITHDRAW_LIMIT",
+                               &TEH_kyc_config.withdraw_limit))
+    return GNUNET_SYSERR;
+  if (0 != strcasecmp (TEH_kyc_config.withdraw_limit.currency,
+                       TEH_currency))
+  {
+    GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                               "exchange",
+                               "KYC_WITHDRAW_LIMIT",
+                               "currency mismatch");
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
 /**
  * Load OAuth2.0 configuration parameters for the exchange server into the
  * #TEH_kyc_config variable.
@@ -1265,6 +1307,12 @@ exchange_serve_process_config (void)
     }
     GNUNET_free (master_public_key_str);
   }
+  if (TEH_KYC_NONE != TEH_kyc_config.mode)
+  {
+    if (GNUNET_OK !=
+        parse_kyc_settings ())
+      return GNUNET_SYSERR;
+  }
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Launching exchange with public key `%s'...\n",
               GNUNET_p2s (&TEH_master_public_key.eddsa_pub));

src/exchange/taler-exchange-httpd.h

@@ -56,6 +56,20 @@ struct TEH_KycOptions
    */
   enum TEH_KycMode mode;
 
+  /**
+   * Maximum amount that can be withdrawn in @e withdraw_period without
+   * needing KYC.
+   * Only valid if @e mode is not #TEH_KYC_NONE and
+   * if @e withdraw_period is non-zero.
+   */
+  struct TALER_Amount withdraw_limit;
+
+  /**
+   * Time period over which @e withdraw_limit applies.
+   * Only valid if @e mode is not #TEH_KYC_NONE.
+   */
+  struct GNUNET_TIME_Relative withdraw_period;
+
   /**
    * Details depending on @e mode.
    */

src/exchange/taler-exchange-httpd_withdraw.c

@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2014-2019 Taler Systems SA
+  Copyright (C) 2014-2021 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
@@ -165,6 +165,7 @@ withdraw_transaction (void *cls,
   struct TALER_EXCHANGEDB_Reserve r;
   enum GNUNET_DB_QueryStatus qs;
   struct TALER_DenominationSignature denom_sig;
+  struct TALER_EXCHANGEDB_KycStatus kyc;
 
 #if OPTIMISTIC_SIGN
   /* store away optimistic signature to protect
@@ -209,7 +210,8 @@ withdraw_transaction (void *cls,
               "Trying to withdraw from reserve: %s\n",
               TALER_B2S (&r.pub));
   qs = TEH_plugin->reserves_get (TEH_plugin->cls,
-                                 &r);
+                                 &r,
+                                 &kyc);
   if (0 > qs)
   {
     if (GNUNET_DB_STATUS_HARD_ERROR == qs)
@@ -268,6 +270,13 @@ withdraw_transaction (void *cls,
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
 
+  if ( (! kyc.ok) &&
+       (TEH_KYC_NONE != TEH_kyc_config.mode) )
+  {
+    // FIXME: check if we are above the limit
+    // for KYC, and if so, deny the transaction!
+  }
+
   /* Balance is good, sign the coin! */
 #if ! OPTIMISTIC_SIGN
   if (NULL == wc->collectable.sig.rsa_signature)

src/exchangedb/Makefile.am

@@ -19,9 +19,7 @@ sql_DATA = \
   exchange-0001.sql \
   exchange-0002.sql \
   exchange-0003.sql \
-  drop0001.sql \
+  drop0001.sql
-  drop0002.sql \
-  drop0003.sql
 
 EXTRA_DIST = \
   exchangedb.conf \

src/exchangedb/drop0001.sql

@@ -22,6 +22,19 @@ BEGIN;
 -- Unlike the other SQL files, it SHOULD be updated to reflect the
 -- latest requirements for dropping tables.
 
+
+-- Drops for exchange-0003.sql
+DROP TABLE IF EXISTS revolving_work_shards CASCADE;
+
+
+-- Drops for exchange-0002.sql
+DROP TABLE IF EXISTS auditors CASCADE;
+DROP TABLE IF EXISTS auditor_denom_sigs CASCADE;
+DROP TABLE IF EXISTS exchange_sign_keys CASCADE;
+DROP TABLE IF EXISTS wire_accounts CASCADE;
+DROP TABLE IF EXISTS signkey_revocations CASCADE;
+DROP TABLE IF EXISTS work_shards CASCADE;
+
 -- Drops for 0001.sql
 DROP TABLE IF EXISTS prewire CASCADE;
 DROP TABLE IF EXISTS recoup CASCADE;
@@ -42,8 +55,15 @@ DROP TABLE IF EXISTS reserves CASCADE;
 DROP TABLE IF EXISTS denomination_revocations CASCADE;
 DROP TABLE IF EXISTS denominations CASCADE;
 
--- Unregister patch (0001.sql)
+
+-- Unregister patch (exchange-0001.sql)
 SELECT _v.unregister_patch('exchange-0001');
 
+-- Unregister patch (exchange-0002.sql)
+SELECT _v.unregister_patch('exchange-0002');
+
+-- Unregister patch (exchange-0003.sql)
+SELECT _v.unregister_patch('exchange-0003');
+
 -- And we're out of here...
 COMMIT;

src/exchangedb/drop0002.sql

@@ -1,31 +0,0 @@
---
--- This file is part of TALER
--- Copyright (C) 2020 Taler Systems SA
---
--- TALER is free software; you can redistribute it and/or modify it under the
--- terms of the GNU 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 General Public License for more details.
---
--- You should have received a copy of the GNU General Public License along with
--- TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
---
-
--- Everything in one big transaction
-BEGIN;
-
--- Unregister patch (0002.sql)
-SELECT _v.unregister_patch('exchange-0002');
-
-DROP TABLE IF EXISTS auditors CASCADE;
-DROP TABLE IF EXISTS auditor_denom_sigs CASCADE;
-DROP TABLE IF EXISTS exchange_sign_keys CASCADE;
-DROP TABLE IF EXISTS wire_accounts CASCADE;
-DROP TABLE IF EXISTS signkey_revocations CASCADE;
-DROP TABLE IF EXISTS work_shards CASCADE;
-
--- And we're out of here...
-COMMIT;

src/exchangedb/drop0003.sql

@@ -1,26 +0,0 @@
---
--- This file is part of TALER
--- Copyright (C) 2020 Taler Systems SA
---
--- TALER is free software; you can redistribute it and/or modify it under the
--- terms of the GNU 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 General Public License for more details.
---
--- You should have received a copy of the GNU General Public License along with
--- TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
---
-
--- Everything in one big transaction
-BEGIN;
-
--- Unregister patch (0003.sql)
-SELECT _v.unregister_patch('exchange-0003');
-
-DROP TABLE IF EXISTS revolving_work_shards CASCADE;
-
--- And we're out of here...
-COMMIT;

src/exchangedb/plugin_exchangedb_postgres.c

@@ -347,6 +347,19 @@ prepare_statements (struct PostgresClosure *pg)
                             "    WHERE denom_pub_hash=$1);",
                             1),
     /* Used in #postgres_reserves_get() */
+    GNUNET_PQ_make_prepare ("reserves_get_with_kyc",
+                            "SELECT"
+                            " current_balance_val"
+                            ",current_balance_frac"
+                            ",expiration_date"
+                            ",gc_date"
+                            ",FALSE AS kyc_ok" // FIXME
+                            ",CAST (0 AS INT8) AS payment_target_uuid" // FIXME
+                            " FROM reserves"
+                            " WHERE reserve_pub=$1"
+                            " LIMIT 1;",
+                            1),
+    /* Used in #reserves_get() */
     GNUNET_PQ_make_prepare ("reserves_get",
                             "SELECT"
                             " current_balance_val"
@@ -3464,10 +3477,56 @@ postgres_iterate_auditor_denominations (
  * @param[in,out] reserve the reserve data.  The public key of the reserve should be
  *          set in this structure; it is used to query the database.  The balance
  *          and expiration are then filled accordingly.
+ * @param[out] kyc set to the KYC status of the reserve
  * @return transaction status
  */
 static enum GNUNET_DB_QueryStatus
 postgres_reserves_get (void *cls,
+                       struct TALER_EXCHANGEDB_Reserve *reserve,
+                       struct TALER_EXCHANGEDB_KycStatus *kyc)
+{
+  struct PostgresClosure *pg = cls;
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_auto_from_type (&reserve->pub),
+    GNUNET_PQ_query_param_end
+  };
+  uint8_t ok8;
+  struct GNUNET_PQ_ResultSpec rs[] = {
+    TALER_PQ_RESULT_SPEC_AMOUNT ("current_balance",
+                                 &reserve->balance),
+    TALER_PQ_result_spec_absolute_time ("expiration_date",
+                                        &reserve->expiry),
+    TALER_PQ_result_spec_absolute_time ("gc_date",
+                                        &reserve->gc),
+    GNUNET_PQ_result_spec_uint64 ("payment_target_uuid",
+                                  &kyc->payment_target_uuid),
+    GNUNET_PQ_result_spec_auto_from_type ("kyc_ok",
+                                          &ok8),
+    GNUNET_PQ_result_spec_end
+  };
+  enum GNUNET_DB_QueryStatus qs;
+
+  qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
+                                                 "reserves_get_with_kyc",
+                                                 params,
+                                                 rs);
+  kyc->type = TALER_EXCHANGEDB_KYC_WITHDRAW;
+  kyc->ok = (0 != ok8);
+  return qs;
+}
+
+
+/**
+ * Get the summary of a reserve.
+ *
+ * @param cls the `struct PostgresClosure` with the plugin-specific state
+ * @param[in,out] reserve the reserve data.  The public key of the reserve should be
+ *          set in this structure; it is used to query the database.  The balance
+ *          and expiration are then filled accordingly.
+ * @return transaction status
+ */
+static enum GNUNET_DB_QueryStatus
+reserves_get_internal (void *cls,
                        struct TALER_EXCHANGEDB_Reserve *reserve)
 {
   struct PostgresClosure *pg = cls;
@@ -3476,9 +3535,12 @@ postgres_reserves_get (void *cls,
     GNUNET_PQ_query_param_end
   };
   struct GNUNET_PQ_ResultSpec rs[] = {
-    TALER_PQ_RESULT_SPEC_AMOUNT ("current_balance", &reserve->balance),
+    TALER_PQ_RESULT_SPEC_AMOUNT ("current_balance",
-    TALER_PQ_result_spec_absolute_time ("expiration_date", &reserve->expiry),
+                                 &reserve->balance),
-    TALER_PQ_result_spec_absolute_time ("gc_date", &reserve->gc),
+    TALER_PQ_result_spec_absolute_time ("expiration_date",
+                                        &reserve->expiry),
+    TALER_PQ_result_spec_absolute_time ("gc_date",
+                                        &reserve->gc),
     GNUNET_PQ_result_spec_end
   };
 
@@ -3699,7 +3761,7 @@ postgres_reserves_in_insert (void *cls,
   {
     enum GNUNET_DB_QueryStatus reserve_exists;
 
-    reserve_exists = postgres_reserves_get (pg,
+    reserve_exists = reserves_get_internal (pg,
                                             &reserve);
     switch (reserve_exists)
     {
@@ -3916,7 +3978,7 @@ postgres_insert_withdraw_info (
   /* update reserve balance */
   reserve.pub = collectable->reserve_pub;
   if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
-      (qs = postgres_reserves_get (pg,
+      (qs = reserves_get_internal (pg,
                                    &reserve)))
   {
     /* Should have been checked before we got here... */
@@ -6875,7 +6937,7 @@ postgres_insert_reserve_closed (
   /* update reserve balance */
   reserve.pub = *reserve_pub;
   if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
-      (qs = postgres_reserves_get (cls,
+      (qs = reserves_get_internal (cls,
                                    &reserve)))
   {
     /* Existence should have been checked before we got here... */
@@ -8667,7 +8729,7 @@ postgres_insert_recoup_request (
 
   /* Update reserve balance */
   reserve.pub = *reserve_pub;
-  qs = postgres_reserves_get (pg,
+  qs = reserves_get_internal (pg,
                               &reserve);
   if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT != qs)
   {

src/exchangedb/test_exchangedb.c

@@ -154,22 +154,25 @@ drop:
  * @return #GNUNET_OK if the given reserve has the same balance and expiration
  *           as the given parameters; #GNUNET_SYSERR if not
  */
-static int
+static enum GNUNET_GenericReturnValue
 check_reserve (const struct TALER_ReservePublicKeyP *pub,
                uint64_t value,
                uint32_t fraction,
                const char *currency)
 {
   struct TALER_EXCHANGEDB_Reserve reserve;
+  struct TALER_EXCHANGEDB_KycStatus kyc;
 
   reserve.pub = *pub;
   FAILIF (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
           plugin->reserves_get (plugin->cls,
-                                &reserve));
+                                &reserve,
+                                &kyc));
   FAILIF (value != reserve.balance.value);
   FAILIF (fraction != reserve.balance.fraction);
-  FAILIF (0 != strcmp (currency, reserve.balance.currency));
+  FAILIF (0 != strcmp (currency,
-
+                       reserve.balance.currency));
+  FAILIF (kyc.ok);
   return GNUNET_OK;
 drop:
   return GNUNET_SYSERR;
@@ -1692,11 +1695,13 @@ run (void *cls)
     struct TALER_EXCHANGEDB_Reserve pre_reserve;
     struct TALER_EXCHANGEDB_Reserve post_reserve;
     struct TALER_Amount delta;
+    struct TALER_EXCHANGEDB_KycStatus kyc;
 
     pre_reserve.pub = reserve_pub;
     FAILIF (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
             plugin->reserves_get (plugin->cls,
-                                  &pre_reserve));
+                                  &pre_reserve,
+                                  &kyc));
     FAILIF (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
             plugin->insert_recoup_request (plugin->cls,
                                            &reserve_pub,
@@ -1709,7 +1714,8 @@ run (void *cls)
     post_reserve.pub = reserve_pub;
     FAILIF (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT !=
             plugin->reserves_get (plugin->cls,
-                                  &post_reserve));
+                                  &post_reserve,
+                                  &kyc));
     FAILIF (0 >=
             TALER_amount_subtract (&delta,
                                    &post_reserve.balance,

src/include/taler_exchangedb_plugin.h

@@ -1533,7 +1533,7 @@ typedef void
  * @param done flag set if the deposit was already executed (or not)
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_DepositCallback)(
   void *cls,
   uint64_t rowid,
@@ -1565,7 +1565,7 @@ typedef int
  * @param rc what is the commitment
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_RefreshesCallback)(
   void *cls,
   uint64_t rowid,
@@ -1585,7 +1585,7 @@ typedef int
  * @param amount_with_fee amount being refunded
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_RefundCoinCallback)(
   void *cls,
   const struct TALER_Amount *amount_with_fee);
@@ -1625,6 +1625,66 @@ struct TALER_EXCHANGEDB_RefreshRevealedCoin
 };
 
 
+/**
+ * Types of operations that require KYC checks.
+ */
+enum TALER_EXCHANGEDB_KycType
+{
+  /**
+   * KYC to be applied for simple withdraws without
+   * the involvement of wallet-to-wallet payments.
+   * Tied to the payto:// of the debited account.
+   */
+  TALER_EXCHANGEDB_KYC_WITHDRAW = 1,
+
+  /**
+   * KYC to be applied for simple deposits to a
+   * merchant's bank account.  Tied to the payto://
+   * of the credited account.
+   */
+  TALER_EXCHANGEDB_KYC_DEPOSIT = 2,
+
+  /**
+   * KYC that is self-applied by a wallet that is exceeding the amount
+   * threshold.  Tied to the reserve-account public key that identifies the
+   * funds-holding wallet.
+   */
+  TALER_EXCHANGEDB_KYC_BALANCE = 3,
+
+  /**
+   * KYC that is triggered upon wallet-to-wallet
+   * payments for the recipient of funds. Tied to the
+   * reserve public key that identifies the receiving
+   * wallet.
+   */
+  TALER_EXCHANGEDB_KYC_W2W = 4
+};
+
+
+/**
+ * Generic KYC status for some operation.
+ */
+struct TALER_EXCHANGEDB_KycStatus
+{
+  /**
+   * Number that identifies the KYC target the operation
+   * was about.
+   */
+  uint64_t payment_target_uuid;
+
+  /**
+   * What kind of KYC operation is this?
+   */
+  enum TALER_EXCHANGEDB_KycType type;
+
+  /**
+   * True if the KYC status is "satisfied".
+   */
+  bool ok;
+
+};
+
+
 /**
  * Function called with information about a refresh order.
  *
@@ -1660,7 +1720,7 @@ typedef void
  * @param amount_with_fee amount that was deposited including fee
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_RefundCallback)(
   void *cls,
   uint64_t rowid,
@@ -1685,7 +1745,7 @@ typedef int
  * @param execution_date when did we receive the funds
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_ReserveInCallback)(
   void *cls,
   uint64_t rowid,
@@ -1745,7 +1805,7 @@ typedef void
  * @param amount_with_fee amount that was withdrawn
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_WithdrawCallback)(
   void *cls,
   uint64_t rowid,
@@ -1838,7 +1898,7 @@ typedef void
  * @param amount amount that was wired
  * @return #GNUNET_OK to continue, #GNUNET_SYSERR to stop iteration
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_WireTransferOutCallback)(
   void *cls,
   uint64_t rowid,
@@ -1859,7 +1919,7 @@ typedef int
  * @param finished did we complete the transfer yet?
  * @return #GNUNET_OK to continue, #GNUNET_SYSERR to stop iteration
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_WirePreparationCallback)(void *cls,
                                             uint64_t rowid,
                                             const char *wire_method,
@@ -1882,7 +1942,7 @@ typedef int
  * @param coin_blind blinding factor used to blind the coin
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_RecoupCallback)(
   void *cls,
   uint64_t rowid,
@@ -1911,7 +1971,7 @@ typedef int
  * @param coin_blind blinding factor used to blind the coin
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_RecoupRefreshCallback)(
   void *cls,
   uint64_t rowid,
@@ -1939,7 +1999,7 @@ typedef int
  * @param wtid identifier used for the wire transfer
  * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
  */
-typedef int
+typedef enum GNUNET_GenericReturnValue
 (*TALER_EXCHANGEDB_ReserveClosedCallback)(
   void *cls,
   uint64_t rowid,
@@ -2295,11 +2355,13 @@ struct TALER_EXCHANGEDB_Plugin
    * @param[in,out] reserve the reserve data.  The public key of the reserve should be set
    *          in this structure; it is used to query the database.  The balance
    *          and expiration are then filled accordingly.
+   * @param[out] kyc set to the KYC status of the reserve
    * @return transaction status
    */
   enum GNUNET_DB_QueryStatus
   (*reserves_get)(void *cls,
-                  struct TALER_EXCHANGEDB_Reserve *reserve);
+                  struct TALER_EXCHANGEDB_Reserve *reserve,
+                  struct TALER_EXCHANGEDB_KycStatus *kyc);
 
 
   /**

src/include/taler_util.h

@@ -136,7 +136,7 @@ TALER_b2s (const void *buf,
  * @param[out] denom set to the amount found in configuration
  * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
  */
-int
+enum GNUNET_GenericReturnValue
 TALER_config_get_amount (const struct GNUNET_CONFIGURATION_Handle *cfg,
                          const char *section,
                          const char *option,
@@ -151,7 +151,7 @@ TALER_config_get_amount (const struct GNUNET_CONFIGURATION_Handle *cfg,
  * @param[out] currency where to write the result
  * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
  */
-int
+enum GNUNET_GenericReturnValue
 TALER_config_get_currency (const struct GNUNET_CONFIGURATION_Handle *cfg,
                            char **currency);
 

src/util/config.c

@@ -32,7 +32,7 @@
  * @param[out] denom set to the amount found in configuration
  * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
  */
-int
+enum GNUNET_GenericReturnValue
 TALER_config_get_amount (const struct GNUNET_CONFIGURATION_Handle *cfg,
                          const char *section,
                          const char *option,
@@ -59,7 +59,7 @@ TALER_config_get_amount (const struct GNUNET_CONFIGURATION_Handle *cfg,
     GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
                                section,
                                option,
-                               "valid amount");
+                               "invalid amount");
     return GNUNET_SYSERR;
   }
   GNUNET_free (str);
@@ -75,7 +75,7 @@ TALER_config_get_amount (const struct GNUNET_CONFIGURATION_Handle *cfg,
  * @param[out] currency where to write the result
  * @return #GNUNET_OK on success, #GNUNET_SYSERR on failure
  */
-int
+enum GNUNET_GenericReturnValue
 TALER_config_get_currency (const struct GNUNET_CONFIGURATION_Handle *cfg,
                            char **currency)
 {
@@ -92,10 +92,10 @@ TALER_config_get_currency (const struct GNUNET_CONFIGURATION_Handle *cfg,
   }
   if (strlen (*currency) >= TALER_CURRENCY_LEN)
   {
-    fprintf (stderr,
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-             "Currency `%s' longer than the allowed limit of %u characters.",
+                "Currency `%s' longer than the allowed limit of %u characters.",
-             *currency,
+                *currency,
-             (unsigned int) TALER_CURRENCY_LEN);
+                (unsigned int) TALER_CURRENCY_LEN);
     GNUNET_free (*currency);
     *currency = NULL;
     return GNUNET_SYSERR;