clean up /withdraw/sign logic

src/mint/taler-mint-httpd_db.c

@@ -22,11 +22,6 @@
  * - actually abstract DB implementation (i.e. via plugin logic)
  *   (this file should remain largely unchanged with the exception
  *    of the PQ-specific DB handle types)
- * - /withdraw/sign: all
- *   + properly check all conditions and handle errors
- *   + properly check transaction logic
- *   + check for leaks
- *   + check low-level API
  * - /refresh/melt: all
  *   + properly check all conditions and handle errors
  *   + properly check transaction logic
@@ -264,11 +259,17 @@ TALER_MINT_db_execute_withdraw_sign (struct MHD_Connection *connection,
 {
   PGconn *db_conn;
   struct ReserveHistory *rh;
+  const struct ReserveHistory *pos;
   struct MintKeyState *key_state;
   struct CollectableBlindcoin collectable;
   struct TALER_MINT_DenomKeyIssuePriv *dki;
+  struct TALER_MINT_DenomKeyIssuePriv *tdki;
   struct GNUNET_CRYPTO_rsa_Signature *sig;
   struct TALER_Amount amount_required;
+  struct TALER_Amount deposit_total;
+  struct TALER_Amount withdraw_total;
+  struct TALER_Amount balance;
+  struct TALER_Amount value;
   struct GNUNET_HashCode h_blind;
   int res;
 
@@ -299,63 +300,102 @@ TALER_MINT_db_execute_withdraw_sign (struct MHD_Connection *connection,
     return res;
   }
   GNUNET_assert (GNUNET_NO == res);
-  rh = TALER_MINT_DB_get_reserve_history (db_conn,
-                                          reserve);
-  if (NULL == rh)
-    return TALER_MINT_reply_json_pack (connection,
-                                       MHD_HTTP_NOT_FOUND,
-                                       "{s:s}",
-                                       "error",
-                                       "Reserve not found");
 
+  /* Check if balance is sufficient */
   key_state = TALER_MINT_key_state_acquire ();
   dki = TALER_MINT_get_denom_key (key_state,
                                   denomination_pub);
-  TALER_MINT_key_state_release (key_state);
   if (NULL == dki)
+  {
+    TALER_MINT_key_state_release (key_state);
     return TALER_MINT_reply_json_pack (connection,
                                        MHD_HTTP_NOT_FOUND,
                                        "{s:s}",
                                        "error",
                                        "Denomination not found");
+  }
+  if (GNUNET_OK !=
+      TALER_MINT_DB_transaction (db_conn))
+  {
+    GNUNET_break (0);
+    TALER_MINT_key_state_release (key_state);
+    return TALER_MINT_reply_internal_db_error (connection);
+  }
 
-  amount_required = TALER_amount_add (TALER_amount_ntoh (dki->issue.value),
+  rh = TALER_MINT_DB_get_reserve_history (db_conn,
-                                      TALER_amount_ntoh (dki->issue.fee_withdraw));
+                                          reserve);
-  // FIX LOGIC!
+  if (NULL == rh)
-#if 0
+  {
-  if (0 < TALER_amount_cmp (amount_required,
+    TALER_MINT_DB_rollback (db_conn);
-                            TALER_amount_ntoh (db_reserve.balance)))
+    TALER_MINT_key_state_release (key_state);
     return TALER_MINT_reply_json_pack (connection,
-                                       MHD_HTTP_PAYMENT_REQUIRED,
+                                       MHD_HTTP_NOT_FOUND,
                                        "{s:s}",
                                        "error",
-                                       "Insufficient funds");
+                                       "Reserve not found");
+  }
 
-  db_reserve.balance = TALER_amount_hton
+  /* calculate amount required including fees */
-    (TALER_amount_subtract (TALER_amount_ntoh (db_reserve.balance),
+  amount_required = TALER_amount_add (TALER_amount_ntoh (dki->issue.value),
-                            amount_required));
+                                      TALER_amount_ntoh (dki->issue.fee_withdraw));
 
+  /* calculate balance of the reserve */
+  res = 0;
+  for (pos = rh; NULL != pos; pos = pos->next)
+  {
+    switch (pos->type)
+    {
+    case TALER_MINT_DB_RO_BANK_TO_MINT:
+      if (0 == (res & 1))
+        deposit_total = pos->details.bank->amount;
+      else
+        deposit_total = TALER_amount_add (deposit_total,
+                                          pos->details.bank->amount);
+      res |= 1;
+      break;
+    case TALER_MINT_DB_RO_WITHDRAW_COIN:
+      tdki = TALER_MINT_get_denom_key (key_state,
+                                       pos->details.withdraw->denom_pub);
+      value = TALER_amount_ntoh (tdki->issue.value);
+      if (0 == (res & 2))
+        withdraw_total = value;
+      else
+        withdraw_total = TALER_amount_add (withdraw_total,
+                                           value);
+      res |= 2;
+      break;
+    }
+  }
+
+  /* FIXME: good place to assert deposit_total > withdraw_total... */
+  balance = TALER_amount_subtract (deposit_total,
+                                   withdraw_total);
+  if (0 < TALER_amount_cmp (amount_required,
+                            balance))
+  {
+    TALER_MINT_key_state_release (key_state);
+    TALER_MINT_DB_rollback (db_conn);
+    res = TALER_MINT_reply_withdraw_sign_insufficient_funds (connection,
+                                                             rh);
+    TALER_MINT_DB_free_reserve_history (rh);
+    return res;
+  }
+  TALER_MINT_DB_free_reserve_history (rh);
+
+  /* Balance is good, sign the coin! */
   sig = GNUNET_CRYPTO_rsa_sign (dki->denom_priv,
                                 blinded_msg,
                                 blinded_msg_len);
+  TALER_MINT_key_state_release (key_state);
   if (NULL == sig)
   {
     GNUNET_break (0);
+    TALER_MINT_DB_rollback (db_conn);
     return TALER_MINT_reply_internal_error (connection,
                                             "Internal error");
   }
 
-  /* transaction start */
+  // FIXME: can we avoid the cast?
-  if (GNUNET_OK !=
-      TALER_MINT_DB_update_reserve (db_conn,
-                                    &db_reserve,
-                                    GNUNET_YES))
-  {
-    GNUNET_break (0);
-    return TALER_MINT_reply_internal_db_error (connection);
-  }
-#endif
-
   collectable.denom_pub = (struct GNUNET_CRYPTO_rsa_PublicKey *) denomination_pub;
   collectable.sig = sig;
   collectable.reserve_pub = *reserve;
@@ -367,17 +407,27 @@ TALER_MINT_db_execute_withdraw_sign (struct MHD_Connection *connection,
   {
     GNUNET_break (0);
     GNUNET_CRYPTO_rsa_signature_free (sig);
+    TALER_MINT_DB_rollback (db_conn);
     return TALER_MINT_reply_internal_db_error (connection);
   }
-  /* transaction end */
+  if (GNUNET_OK !=
-  GNUNET_CRYPTO_rsa_signature_free (sig);
+      TALER_MINT_DB_commit (db_conn))
-  return TALER_MINT_reply_withdraw_sign_success (connection,
+  {
-                                                 &collectable);
+    LOG_WARNING ("/withdraw/sign transaction commit failed\n");
+    return TALER_MINT_reply_commit_error (connection);
   }
+  res = TALER_MINT_reply_withdraw_sign_success (connection,
+                                                &collectable);
+  GNUNET_CRYPTO_rsa_signature_free (sig);
+  return res;
+}
+
+
+
 
 
 /**
- * Insert  all requested denominations  into the  db, and  compute the
+ * Insert  all requested denominations  into the DB, and  compute the
  * required cost of the denominations, including fees.
  *
  * @param connection the connection to send an error response to
@@ -615,11 +665,11 @@ TALER_MINT_db_execute_refresh_melt (struct MHD_Connection *connection,
   }
 
 
-  if (GNUNET_OK != TALER_MINT_DB_transaction (db_conn))
+  if (GNUNET_OK !=
+      TALER_MINT_DB_transaction (db_conn))
   {
-    // FIXME: return 'internal error'?
     GNUNET_break (0);
-    return MHD_NO;
+    return TALER_MINT_reply_internal_db_error (connection);
   }
 
   if (GNUNET_OK != TALER_MINT_DB_create_refresh_session (db_conn,
@@ -678,10 +728,11 @@ TALER_MINT_db_execute_refresh_melt (struct MHD_Connection *connection,
                                        "not enough coins melted");
   }
 
-  if (GNUNET_OK != TALER_MINT_DB_commit (db_conn))
+  if (GNUNET_OK !=
+      TALER_MINT_DB_commit (db_conn))
   {
-    GNUNET_break (0);
+    LOG_WARNING ("/refresh/melt transaction commit failed\n");
-    return MHD_NO;
+    return TALER_MINT_reply_commit_error (connection);
   }
   if (GNUNET_OK !=
       (res = TALER_MINT_DB_get_refresh_session (db_conn,
@@ -795,11 +846,11 @@ TALER_MINT_db_execute_refresh_commit (struct MHD_Connection *connection,
     return MHD_NO;
   }
 
-  if (GNUNET_OK != TALER_MINT_DB_transaction (db_conn))
+  if (GNUNET_OK !=
+      TALER_MINT_DB_transaction (db_conn))
   {
-    // FIXME: return 'internal error'?
     GNUNET_break (0);
-    return MHD_NO;
+    return TALER_MINT_reply_internal_db_error (connection);
   }
 
   /* Re-fetch the session information from the database,
@@ -816,11 +867,11 @@ TALER_MINT_db_execute_refresh_commit (struct MHD_Connection *connection,
     return MHD_NO;
   }
 
-  if (GNUNET_OK != TALER_MINT_DB_commit (db_conn))
+  if (GNUNET_OK !=
+      TALER_MINT_DB_commit (db_conn))
   {
-    // FIXME: return 'internal error'?
+    LOG_WARNING ("/refresh/commit transaction commit failed\n");
-    GNUNET_break (0);
+    return TALER_MINT_reply_commit_error (connection);
-    return MHD_NO;
   }
 
   return TALER_MINT_reply_refresh_commit_success (connection, &refresh_session);
@@ -1095,11 +1146,11 @@ TALER_MINT_db_execute_refresh_reveal (struct MHD_Connection *connection,
   }
 
 
-  if (GNUNET_OK != TALER_MINT_DB_transaction (db_conn))
+  if (GNUNET_OK !=
+      TALER_MINT_DB_transaction (db_conn))
   {
     GNUNET_break (0);
-            // FIXME: return error code!
+    return TALER_MINT_reply_internal_db_error (connection);
-    return MHD_NO;
   }
 
   for (j = 0; j < refresh_session.num_newcoins; j++)
@@ -1169,10 +1220,11 @@ TALER_MINT_db_execute_refresh_reveal (struct MHD_Connection *connection,
     return MHD_NO;
   }
 
-  if (GNUNET_OK != TALER_MINT_DB_commit (db_conn))
+  if (GNUNET_OK !=
+      TALER_MINT_DB_commit (db_conn))
   {
-    GNUNET_break (0);
+    LOG_WARNING ("/refresh/reveal transaction commit failed\n");
-    return MHD_NO;
+    return TALER_MINT_reply_commit_error (connection);
   }
 
   return helper_refresh_reveal_send_response (connection,

src/mint/taler-mint-httpd_responses.c

@@ -351,26 +351,25 @@ TALER_MINT_reply_insufficient_funds (struct MHD_Connection *connection,
 
 
 /**
- * Send reserve status information to client.
+ * Compile the history of a reserve into a JSON object
+ * and calculate the total balance.
  *
- * @param connection connection to the client
+ * @param rh reserve history to JSON-ify
- * @param rh reserve history to return
+ * @param balance[OUT] set to current reserve balance
- * @return MHD result code
+ * @return json representation of the @a rh
  */
-int
+static json_t *
-TALER_MINT_reply_withdraw_status_success (struct MHD_Connection *connection,
+compile_reserve_history (const struct ReserveHistory *rh,
-                                          const struct ReserveHistory *rh)
+                         struct TALER_Amount *balance)
 {
   struct TALER_Amount deposit_total;
   struct TALER_Amount withdraw_total;
-  struct TALER_Amount balance;
   struct TALER_Amount value;
-  json_t *json_balance;
   json_t *json_history;
   int ret;
-  struct MintKeyState *key_state;
   const struct ReserveHistory *pos;
   struct TALER_MINT_DenomKeyIssuePriv *dki;
+  struct MintKeyState *key_state;
 
   json_history = json_array ();
   ret = 0;
@@ -425,8 +424,30 @@ TALER_MINT_reply_withdraw_status_success (struct MHD_Connection *connection,
   }
   TALER_MINT_key_state_release (key_state);
 
-  balance = TALER_amount_subtract (deposit_total,
+  *balance = TALER_amount_subtract (deposit_total,
                                     withdraw_total);
+  return json_history;
+}
+
+
+/**
+ * Send reserve status information to client.
+ *
+ * @param connection connection to the client
+ * @param rh reserve history to return
+ * @return MHD result code
+ */
+int
+TALER_MINT_reply_withdraw_status_success (struct MHD_Connection *connection,
+                                          const struct ReserveHistory *rh)
+{
+  json_t *json_balance;
+  json_t *json_history;
+  struct TALER_Amount balance;
+  int ret;
+
+  json_history = compile_reserve_history (rh,
+                                          &balance);
   json_balance = TALER_JSON_from_amount (balance);
   ret = TALER_MINT_reply_json_pack (connection,
                                     MHD_HTTP_OK,
@@ -439,6 +460,39 @@ TALER_MINT_reply_withdraw_status_success (struct MHD_Connection *connection,
 }
 
 
+/**
+ * Send reserve status information to client with the
+ * message that we have insufficient funds for the
+ * requested /withdraw/sign operation.
+ *
+ * @param connection connection to the client
+ * @param rh reserve history to return
+ * @return MHD result code
+ */
+int
+TALER_MINT_reply_withdraw_sign_insufficient_funds (struct MHD_Connection *connection,
+                                                   const struct ReserveHistory *rh)
+{
+  json_t *json_balance;
+  json_t *json_history;
+  struct TALER_Amount balance;
+  int ret;
+
+  json_history = compile_reserve_history (rh,
+                                          &balance);
+  json_balance = TALER_JSON_from_amount (balance);
+  ret = TALER_MINT_reply_json_pack (connection,
+                                    MHD_HTTP_PAYMENT_REQUIRED,
+                                    "{s:s, s:o, s:o}",
+                                    "error", "Insufficient funds"
+                                    "balance", json_balance,
+                                    "history", json_history);
+  json_decref (json_history);
+  json_decref (json_balance);
+  return ret;
+}
+
+
 /**
  * Send blinded coin information to client.
  *

src/mint/taler-mint-httpd_responses.h

@@ -208,6 +208,20 @@ TALER_MINT_reply_withdraw_status_success (struct MHD_Connection *connection,
                                           const struct ReserveHistory *rh);
 
 
+/**
+ * Send reserve status information to client with the
+ * message that we have insufficient funds for the
+ * requested /withdraw/sign operation.
+ *
+ * @param connection connection to the client
+ * @param rh reserve history to return
+ * @return MHD result code
+ */
+int
+TALER_MINT_reply_withdraw_sign_insufficient_funds (struct MHD_Connection *connection,
+                                                   const struct ReserveHistory *rh);
+
+
 /**
  * Send blinded coin information to client.
  *