start.c (3334B)
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 TALER_AUDITORDB_start (struct TALER_AUDITORDB_PostgresContext *pg, 29 const char *transaction_name) 30 { 31 struct GNUNET_PQ_ExecuteStatement es[] = { 32 GNUNET_PQ_make_execute ("START TRANSACTION ISOLATION LEVEL SERIALIZABLE"), 33 GNUNET_PQ_EXECUTE_STATEMENT_END 34 }; 35 36 GNUNET_assert (NULL != transaction_name); 37 GNUNET_break (GNUNET_OK == 38 TALER_AUDITORDB_preflight (pg)); 39 if (GNUNET_OK != 40 GNUNET_PQ_exec_statements (pg->conn, 41 es)) 42 { 43 TALER_LOG_ERROR ("Failed to start transaction\n"); 44 GNUNET_break (0); 45 return GNUNET_SYSERR; 46 } 47 pg->transaction_name = transaction_name; 48 return GNUNET_OK; 49 } 50 51 52 void 53 TALER_AUDITORDB_rollback (struct TALER_AUDITORDB_PostgresContext *pg) 54 { 55 struct GNUNET_PQ_ExecuteStatement es[] = { 56 GNUNET_PQ_make_execute ("ROLLBACK"), 57 GNUNET_PQ_EXECUTE_STATEMENT_END 58 }; 59 60 GNUNET_break (GNUNET_OK == 61 GNUNET_PQ_exec_statements (pg->conn, 62 es)); 63 pg->transaction_name = NULL; 64 } 65 66 67 enum GNUNET_DB_QueryStatus 68 TALER_AUDITORDB_commit (struct TALER_AUDITORDB_PostgresContext *pg) 69 { 70 struct GNUNET_PQ_QueryParam params[] = { 71 GNUNET_PQ_query_param_end 72 }; 73 74 enum GNUNET_DB_QueryStatus qs; 75 PGresult *result; 76 77 PREPARE (pg, 78 "commit", 79 "COMMIT"); 80 result = GNUNET_PQ_exec_prepared (pg->conn, 81 "commit", 82 params); 83 qs = GNUNET_PQ_eval_result (pg->conn, 84 "commit", 85 result); 86 if ( (0 <= qs) && 87 (NULL != result) && 88 (0 == strcmp ("ROLLBACK", 89 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 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, 97 "Transaction `%s' was rolled back by the database\n", 98 pg->transaction_name); 99 qs = GNUNET_DB_STATUS_SOFT_ERROR; 100 } 101 PQclear (result); 102 pg->transaction_name = NULL; 103 return qs; 104 }