Line data    Source code

       1              : /*
       2              :    This file is part of TALER
       3              :    Copyright (C) 2026 Taler Systems SA
       4              : 
       5              :    TALER is free software; you can redistribute it and/or modify it under the
       6              :    terms of the GNU General Public License as published by the Free Software
       7              :    Foundation; either version 3, or (at your option) any later version.
       8              : 
       9              :    TALER is distributed in the hope that it will be useful, but WITHOUT ANY
      10              :    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
      11              :    A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
      12              : 
      13              :    You should have received a copy of the GNU General Public License along with
      14              :    TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
      15              :  */
      16              : /**
      17              :  * @file src/auditordb/start.c
      18              :  * @brief Implementation of the start, commit and rollback functions for Postgres
      19              :  * @author Christian Grothoff
      20              :  */
      21              : #include "taler/taler_pq_lib.h"
      22              : #include "auditor-database/start.h"
      23              : #include "auditor-database/preflight.h"
      24              : #include "pg_helper.h"
      25              : 
      26              : 
      27              : enum GNUNET_GenericReturnValue
      28           30 : TALER_AUDITORDB_start (struct TALER_AUDITORDB_PostgresContext *pg,
      29              :                        const char *transaction_name)
      30              : {
      31           30 :   struct GNUNET_PQ_ExecuteStatement es[] = {
      32           30 :     GNUNET_PQ_make_execute ("START TRANSACTION ISOLATION LEVEL SERIALIZABLE"),
      33              :     GNUNET_PQ_EXECUTE_STATEMENT_END
      34              :   };
      35              : 
      36           30 :   GNUNET_assert (NULL != transaction_name);
      37           30 :   GNUNET_break (GNUNET_OK ==
      38              :                 TALER_AUDITORDB_preflight (pg));
      39           30 :   if (GNUNET_OK !=
      40           30 :       GNUNET_PQ_exec_statements (pg->conn,
      41              :                                  es))
      42              :   {
      43            0 :     TALER_LOG_ERROR ("Failed to start transaction\n");
      44            0 :     GNUNET_break (0);
      45            0 :     return GNUNET_SYSERR;
      46              :   }
      47           30 :   pg->transaction_name = transaction_name;
      48           30 :   return GNUNET_OK;
      49              : }
      50              : 
      51              : 
      52              : void
      53           12 : TALER_AUDITORDB_rollback (struct TALER_AUDITORDB_PostgresContext *pg)
      54              : {
      55           12 :   struct GNUNET_PQ_ExecuteStatement es[] = {
      56           12 :     GNUNET_PQ_make_execute ("ROLLBACK"),
      57              :     GNUNET_PQ_EXECUTE_STATEMENT_END
      58              :   };
      59              : 
      60           12 :   GNUNET_break (GNUNET_OK ==
      61              :                 GNUNET_PQ_exec_statements (pg->conn,
      62              :                                            es));
      63           12 :   pg->transaction_name = NULL;
      64           12 : }
      65              : 
      66              : 
      67              : enum GNUNET_DB_QueryStatus
      68           19 : TALER_AUDITORDB_commit (struct TALER_AUDITORDB_PostgresContext *pg)
      69              : {
      70           19 :   struct GNUNET_PQ_QueryParam params[] = {
      71              :     GNUNET_PQ_query_param_end
      72              :   };
      73              : 
      74              :   enum GNUNET_DB_QueryStatus qs;
      75              :   PGresult *result;
      76              : 
      77           19 :   PREPARE (pg,
      78              :            "commit",
      79              :            "COMMIT");
      80           19 :   result = GNUNET_PQ_exec_prepared (pg->conn,
      81              :                                     "commit",
      82              :                                     params);
      83           19 :   qs = GNUNET_PQ_eval_result (pg->conn,
      84              :                               "commit",
      85              :                               result);
      86           19 :   if ( (0 <= qs) &&
      87           19 :        (NULL != result) &&
      88           19 :        (0 == strcmp ("ROLLBACK",
      89           19 :                      PQcmdStatus (result))) )
      90              :   {
      91              :     /* Postgres accepts COMMIT on an already-aborted transaction and
      92              :        answers PGRES_COMMAND_OK with the command tag ROLLBACK, which is
      93              :        otherwise indistinguishable from a successful commit.  Report it
      94              :        as a soft error so the caller retries instead of checkpointing
      95              :        progress for writes that are gone. */
      96            0 :     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
      97              :                 "Transaction `%s' was rolled back by the database\n",
      98              :                 pg->transaction_name);
      99            0 :     qs = GNUNET_DB_STATUS_SOFT_ERROR;
     100              :   }
     101           19 :   PQclear (result);
     102           19 :   pg->transaction_name = NULL;
     103           19 :   return qs;
     104              : }