/ src / wallet / sqlite.cpp
sqlite.cpp
  1  // Copyright (c) 2020-present The Bitcoin Core developers
  2  // Distributed under the MIT software license, see the accompanying
  3  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  4  
  5  #include <bitcoin-build-config.h> // IWYU pragma: keep
  6  
  7  #include <wallet/sqlite.h>
  8  
  9  #include <chainparams.h>
 10  #include <crypto/common.h>
 11  #include <logging.h>
 12  #include <sync.h>
 13  #include <util/check.h>
 14  #include <util/fs_helpers.h>
 15  #include <util/strencodings.h>
 16  #include <util/translation.h>
 17  #include <wallet/db.h>
 18  
 19  #include <sqlite3.h>
 20  
 21  #include <cstdint>
 22  #include <optional>
 23  #include <utility>
 24  #include <vector>
 25  
 26  namespace wallet {
 27  static constexpr int32_t WALLET_SCHEMA_VERSION = 0;
 28  
 29  static std::span<const std::byte> SpanFromBlob(sqlite3_stmt* stmt, int col)
 30  {
 31      return {reinterpret_cast<const std::byte*>(sqlite3_column_blob(stmt, col)),
 32              static_cast<size_t>(sqlite3_column_bytes(stmt, col))};
 33  }
 34  
 35  static void ErrorLogCallback(void* arg, int code, const char* msg)
 36  {
 37      // From sqlite3_config() documentation for the SQLITE_CONFIG_LOG option:
 38      // "The void pointer that is the second argument to SQLITE_CONFIG_LOG is passed through as
 39      // the first parameter to the application-defined logger function whenever that function is
 40      // invoked."
 41      // Assert that this is the case:
 42      assert(arg == nullptr);
 43      LogWarning("SQLite Error. Code: %d. Message: %s", code, msg);
 44  }
 45  
 46  static int TraceSqlCallback(unsigned code, void* context, void* param1, void* param2)
 47  {
 48      auto* db = static_cast<SQLiteDatabase*>(context);
 49      if (code == SQLITE_TRACE_STMT) {
 50          auto* stmt = static_cast<sqlite3_stmt*>(param1);
 51          // To be conservative and avoid leaking potentially secret information
 52          // in the log file, only expand statements that query the database, not
 53          // statements that update the database.
 54          char* expanded{sqlite3_stmt_readonly(stmt) ? sqlite3_expanded_sql(stmt) : nullptr};
 55          LogTrace(BCLog::WALLETDB, "[%s] SQLite Statement: %s\n", db->Filename(), expanded ? expanded : sqlite3_sql(stmt));
 56          if (expanded) sqlite3_free(expanded);
 57      }
 58      return SQLITE_OK;
 59  }
 60  
 61  static bool BindBlobToStatement(sqlite3_stmt* stmt,
 62                                  int index,
 63                                  std::span<const std::byte> blob,
 64                                  const std::string& description)
 65  {
 66      // Pass a pointer to the empty string "" below instead of passing the
 67      // blob.data() pointer if the blob.data() pointer is null. Passing a null
 68      // data pointer to bind_blob would cause sqlite to bind the SQL NULL value
 69      // instead of the empty blob value X'', which would mess up SQL comparisons.
 70      int res = sqlite3_bind_blob(stmt, index, blob.data() ? static_cast<const void*>(blob.data()) : "", blob.size(), SQLITE_STATIC);
 71      if (res != SQLITE_OK) {
 72          LogWarning("Unable to bind %s to statement: %s", description, sqlite3_errstr(res));
 73          sqlite3_clear_bindings(stmt);
 74          sqlite3_reset(stmt);
 75          return false;
 76      }
 77  
 78      return true;
 79  }
 80  
 81  static std::optional<int> ReadPragmaInteger(sqlite3* db, const std::string& key, const std::string& description, bilingual_str& error)
 82  {
 83      std::string stmt_text = strprintf("PRAGMA %s", key);
 84      sqlite3_stmt* pragma_read_stmt{nullptr};
 85      int ret = sqlite3_prepare_v2(db, stmt_text.c_str(), -1, &pragma_read_stmt, nullptr);
 86      if (ret != SQLITE_OK) {
 87          sqlite3_finalize(pragma_read_stmt);
 88          error = Untranslated(strprintf("SQLiteDatabase: Failed to prepare the statement to fetch %s: %s", description, sqlite3_errstr(ret)));
 89          return std::nullopt;
 90      }
 91      ret = sqlite3_step(pragma_read_stmt);
 92      if (ret != SQLITE_ROW) {
 93          sqlite3_finalize(pragma_read_stmt);
 94          error = Untranslated(strprintf("SQLiteDatabase: Failed to fetch %s: %s", description, sqlite3_errstr(ret)));
 95          return std::nullopt;
 96      }
 97      int result = sqlite3_column_int(pragma_read_stmt, 0);
 98      sqlite3_finalize(pragma_read_stmt);
 99      return result;
100  }
101  
102  static void SetPragma(sqlite3* db, const std::string& key, const std::string& value, const std::string& err_msg)
103  {
104      std::string stmt_text = strprintf("PRAGMA %s = %s", key, value);
105      int ret = sqlite3_exec(db, stmt_text.c_str(), nullptr, nullptr, nullptr);
106      if (ret != SQLITE_OK) {
107          throw std::runtime_error(strprintf("SQLiteDatabase: %s: %s\n", err_msg, sqlite3_errstr(ret)));
108      }
109  }
110  
111  Mutex SQLiteDatabase::g_sqlite_mutex;
112  int SQLiteDatabase::g_sqlite_count = 0;
113  
114  SQLiteDatabase::SQLiteDatabase(const fs::path& dir_path, const fs::path& file_path, const DatabaseOptions& options, bool mock)
115      : WalletDatabase(), m_mock(mock), m_dir_path(dir_path), m_file_path(fs::PathToString(file_path)), m_write_semaphore(1), m_use_unsafe_sync(options.use_unsafe_sync)
116  {
117      {
118          LOCK(g_sqlite_mutex);
119          if (++g_sqlite_count == 1) {
120              // Setup logging
121              int ret = sqlite3_config(SQLITE_CONFIG_LOG, ErrorLogCallback, nullptr);
122              if (ret != SQLITE_OK) {
123                  throw std::runtime_error(strprintf("SQLiteDatabase: Failed to setup error log: %s\n", sqlite3_errstr(ret)));
124              }
125              // Force serialized threading mode
126              ret = sqlite3_config(SQLITE_CONFIG_SERIALIZED);
127              if (ret != SQLITE_OK) {
128                  throw std::runtime_error(strprintf("SQLiteDatabase: Failed to configure serialized threading mode: %s\n", sqlite3_errstr(ret)));
129              }
130          }
131          int ret = sqlite3_initialize(); // This is a no-op if sqlite3 is already initialized
132          if (ret != SQLITE_OK) {
133              throw std::runtime_error(strprintf("SQLiteDatabase: Failed to initialize SQLite: %s\n", sqlite3_errstr(ret)));
134          }
135      }
136  
137      try {
138          Open();
139      } catch (const std::runtime_error&) {
140          // If open fails, cleanup this object and rethrow the exception
141          Cleanup();
142          throw;
143      }
144  }
145  
146  void SQLiteBatch::SetupSQLStatements()
147  {
148      const std::vector<std::pair<sqlite3_stmt**, const char*>> statements{
149          {&m_read_stmt, "SELECT value FROM main WHERE key = ?"},
150          {&m_insert_stmt, "INSERT INTO main VALUES(?, ?)"},
151          {&m_overwrite_stmt, "INSERT or REPLACE into main values(?, ?)"},
152          {&m_delete_stmt, "DELETE FROM main WHERE key = ?"},
153          {&m_delete_prefix_stmt, "DELETE FROM main WHERE instr(key, ?) = 1"},
154      };
155  
156      for (const auto& [stmt_prepared, stmt_text] : statements) {
157          if (*stmt_prepared == nullptr) {
158              int res = sqlite3_prepare_v2(m_database.m_db, stmt_text, -1, stmt_prepared, nullptr);
159              if (res != SQLITE_OK) {
160                  throw std::runtime_error(strprintf(
161                      "SQLiteDatabase: Failed to setup SQL statements: %s\n", sqlite3_errstr(res)));
162              }
163          }
164      }
165  }
166  
167  SQLiteDatabase::~SQLiteDatabase()
168  {
169      Cleanup();
170  }
171  
172  void SQLiteDatabase::Cleanup() noexcept
173  {
174      AssertLockNotHeld(g_sqlite_mutex);
175  
176      Close();
177  
178      LOCK(g_sqlite_mutex);
179      if (--g_sqlite_count == 0) {
180          int ret = sqlite3_shutdown();
181          if (ret != SQLITE_OK) {
182              LogWarning("SQLiteDatabase: Failed to shutdown SQLite: %s", sqlite3_errstr(ret));
183          }
184      }
185  }
186  
187  bool SQLiteDatabase::Verify(bilingual_str& error)
188  {
189      assert(m_db);
190  
191      // Check the application ID matches our network magic
192      auto read_result = ReadPragmaInteger(m_db, "application_id", "the application id", error);
193      if (!read_result.has_value()) return false;
194      uint32_t app_id = static_cast<uint32_t>(read_result.value());
195      uint32_t net_magic = ReadBE32(Params().MessageStart().data());
196      if (app_id != net_magic) {
197          error = strprintf(_("SQLiteDatabase: Unexpected application id. Expected %u, got %u"), net_magic, app_id);
198          return false;
199      }
200  
201      // Check our schema version
202      read_result = ReadPragmaInteger(m_db, "user_version", "sqlite wallet schema version", error);
203      if (!read_result.has_value()) return false;
204      int32_t user_ver = read_result.value();
205      if (user_ver != WALLET_SCHEMA_VERSION) {
206          error = strprintf(_("SQLiteDatabase: Unknown sqlite wallet schema version %d. Only version %d is supported"), user_ver, WALLET_SCHEMA_VERSION);
207          return false;
208      }
209  
210      sqlite3_stmt* stmt{nullptr};
211      int ret = sqlite3_prepare_v2(m_db, "PRAGMA integrity_check", -1, &stmt, nullptr);
212      if (ret != SQLITE_OK) {
213          sqlite3_finalize(stmt);
214          error = strprintf(_("SQLiteDatabase: Failed to prepare statement to verify database: %s"), sqlite3_errstr(ret));
215          return false;
216      }
217      while (true) {
218          ret = sqlite3_step(stmt);
219          if (ret == SQLITE_DONE) {
220              break;
221          }
222          if (ret != SQLITE_ROW) {
223              error = strprintf(_("SQLiteDatabase: Failed to execute statement to verify database: %s"), sqlite3_errstr(ret));
224              break;
225          }
226          const char* msg = (const char*)sqlite3_column_text(stmt, 0);
227          if (!msg) {
228              error = strprintf(_("SQLiteDatabase: Failed to read database verification error: %s"), sqlite3_errstr(ret));
229              break;
230          }
231          std::string str_msg(msg);
232          if (str_msg == "ok") {
233              continue;
234          }
235          if (error.empty()) {
236              error = _("Failed to verify database") + Untranslated("\n");
237          }
238          error += Untranslated(strprintf("%s\n", str_msg));
239      }
240      sqlite3_finalize(stmt);
241      return error.empty();
242  }
243  
244  void SQLiteDatabase::Open()
245  {
246      int flags = SQLITE_OPEN_FULLMUTEX | SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
247      if (m_mock) {
248          flags |= SQLITE_OPEN_MEMORY; // In memory database for mock db
249      }
250  
251      if (m_db == nullptr) {
252          if (!m_mock) {
253              TryCreateDirectories(m_dir_path);
254          }
255          int ret = sqlite3_open_v2(m_file_path.c_str(), &m_db, flags, nullptr);
256          if (ret != SQLITE_OK) {
257              throw std::runtime_error(strprintf("SQLiteDatabase: Failed to open database: %s\n", sqlite3_errstr(ret)));
258          }
259          ret = sqlite3_extended_result_codes(m_db, 1);
260          if (ret != SQLITE_OK) {
261              throw std::runtime_error(strprintf("SQLiteDatabase: Failed to enable extended result codes: %s\n", sqlite3_errstr(ret)));
262          }
263          // Trace SQL statements if tracing is enabled with -debug=walletdb -loglevel=walletdb:trace
264          if (LogAcceptCategory(BCLog::WALLETDB, BCLog::Level::Trace)) {
265             ret = sqlite3_trace_v2(m_db, SQLITE_TRACE_STMT, TraceSqlCallback, this);
266             if (ret != SQLITE_OK) {
267                 LogWarning("Failed to enable SQL tracing for %s", Filename());
268             }
269          }
270      }
271  
272      if (sqlite3_db_readonly(m_db, "main") != 0) {
273          throw std::runtime_error("SQLiteDatabase: Database opened in readonly mode but read-write permissions are needed");
274      }
275  
276      // Acquire an exclusive lock on the database
277      // First change the locking mode to exclusive
278      SetPragma(m_db, "locking_mode", "exclusive", "Unable to change database locking mode to exclusive");
279      // Now begin a transaction to acquire the exclusive lock. This lock won't be released until we close because of the exclusive locking mode.
280      int ret = sqlite3_exec(m_db, "BEGIN EXCLUSIVE TRANSACTION", nullptr, nullptr, nullptr);
281      if (ret != SQLITE_OK) {
282          throw std::runtime_error("SQLiteDatabase: Unable to obtain an exclusive lock on the database, is it being used by another instance of " CLIENT_NAME "?\n");
283      }
284      ret = sqlite3_exec(m_db, "COMMIT", nullptr, nullptr, nullptr);
285      if (ret != SQLITE_OK) {
286          throw std::runtime_error(strprintf("SQLiteDatabase: Unable to end exclusive lock transaction: %s\n", sqlite3_errstr(ret)));
287      }
288  
289      // Enable fullfsync for the platforms that use it
290      SetPragma(m_db, "fullfsync", "true", "Failed to enable fullfsync");
291  
292      if (m_use_unsafe_sync) {
293          // Use normal synchronous mode for the journal
294          LogWarning("SQLite is configured to not wait for data to be flushed to disk. Data loss and corruption may occur.");
295          SetPragma(m_db, "synchronous", "OFF", "Failed to set synchronous mode to OFF");
296      }
297  
298      // Make the table for our key-value pairs
299      // First check that the main table exists
300      sqlite3_stmt* check_main_stmt{nullptr};
301      ret = sqlite3_prepare_v2(m_db, "SELECT name FROM sqlite_master WHERE type='table' AND name='main'", -1, &check_main_stmt, nullptr);
302      if (ret != SQLITE_OK) {
303          throw std::runtime_error(strprintf("SQLiteDatabase: Failed to prepare statement to check table existence: %s\n", sqlite3_errstr(ret)));
304      }
305      ret = sqlite3_step(check_main_stmt);
306      if (sqlite3_finalize(check_main_stmt) != SQLITE_OK) {
307          throw std::runtime_error(strprintf("SQLiteDatabase: Failed to finalize statement checking table existence: %s\n", sqlite3_errstr(ret)));
308      }
309      bool table_exists;
310      if (ret == SQLITE_DONE) {
311          table_exists = false;
312      } else if (ret == SQLITE_ROW) {
313          table_exists = true;
314      } else {
315          throw std::runtime_error(strprintf("SQLiteDatabase: Failed to execute statement to check table existence: %s\n", sqlite3_errstr(ret)));
316      }
317  
318      // Do the db setup things because the table doesn't exist only when we are creating a new wallet
319      if (!table_exists) {
320          ret = sqlite3_exec(m_db, "CREATE TABLE main(key BLOB PRIMARY KEY NOT NULL, value BLOB NOT NULL)", nullptr, nullptr, nullptr);
321          if (ret != SQLITE_OK) {
322              throw std::runtime_error(strprintf("SQLiteDatabase: Failed to create new database: %s\n", sqlite3_errstr(ret)));
323          }
324  
325          // Set the application id
326          uint32_t app_id = ReadBE32(Params().MessageStart().data());
327          SetPragma(m_db, "application_id", strprintf("%d", static_cast<int32_t>(app_id)),
328                    "Failed to set the application id");
329  
330          // Set the user version
331          SetPragma(m_db, "user_version", strprintf("%d", WALLET_SCHEMA_VERSION),
332                    "Failed to set the wallet schema version");
333      }
334  }
335  
336  bool SQLiteDatabase::Rewrite()
337  {
338      // Rewrite the database using the VACUUM command: https://sqlite.org/lang_vacuum.html
339      int ret = sqlite3_exec(m_db, "VACUUM", nullptr, nullptr, nullptr);
340      return ret == SQLITE_OK;
341  }
342  
343  bool SQLiteDatabase::Backup(const std::string& dest) const
344  {
345      sqlite3* db_copy;
346      int res = sqlite3_open(dest.c_str(), &db_copy);
347      if (res != SQLITE_OK) {
348          sqlite3_close(db_copy);
349          return false;
350      }
351      sqlite3_backup* backup = sqlite3_backup_init(db_copy, "main", m_db, "main");
352      if (!backup) {
353          LogWarning("Unable to begin sqlite backup: %s", sqlite3_errmsg(m_db));
354          sqlite3_close(db_copy);
355          return false;
356      }
357      // Specifying -1 will copy all of the pages
358      res = sqlite3_backup_step(backup, -1);
359      if (res != SQLITE_DONE) {
360          LogWarning("Unable to continue sqlite backup: %s", sqlite3_errstr(res));
361          sqlite3_backup_finish(backup);
362          sqlite3_close(db_copy);
363          return false;
364      }
365      res = sqlite3_backup_finish(backup);
366      sqlite3_close(db_copy);
367      return res == SQLITE_OK;
368  }
369  
370  void SQLiteDatabase::Close()
371  {
372      int res = sqlite3_close(m_db);
373      if (res != SQLITE_OK) {
374          throw std::runtime_error(strprintf("SQLiteDatabase: Failed to close database: %s\n", sqlite3_errstr(res)));
375      }
376      m_db = nullptr;
377  }
378  
379  bool SQLiteDatabase::HasActiveTxn()
380  {
381      // 'sqlite3_get_autocommit' returns true by default, and false if a transaction has begun and not been committed or rolled back.
382      return m_db && sqlite3_get_autocommit(m_db) == 0;
383  }
384  
385  int SQliteExecHandler::Exec(SQLiteDatabase& database, const std::string& statement)
386  {
387      return sqlite3_exec(database.m_db, statement.data(), nullptr, nullptr, nullptr);
388  }
389  
390  std::unique_ptr<DatabaseBatch> SQLiteDatabase::MakeBatch()
391  {
392      // We ignore flush_on_close because we don't do manual flushing for SQLite
393      return std::make_unique<SQLiteBatch>(*this);
394  }
395  
396  SQLiteBatch::SQLiteBatch(SQLiteDatabase& database)
397      : m_database(database)
398  {
399      // Make sure we have a db handle
400      assert(m_database.m_db);
401  
402      SetupSQLStatements();
403  }
404  
405  void SQLiteBatch::Close()
406  {
407      bool force_conn_refresh = false;
408  
409      // If we began a transaction, and it wasn't committed, abort the transaction in progress
410      if (m_txn) {
411          if (TxnAbort()) {
412              LogWarning("SQLiteBatch: Batch closed unexpectedly without the transaction being explicitly committed or aborted");
413          } else {
414              // If transaction cannot be aborted, it means there is a bug or there has been data corruption. Try to recover in this case
415              // by closing and reopening the database. Closing the database should also ensure that any changes made since the transaction
416              // was opened will be rolled back and future transactions can succeed without committing old data.
417              force_conn_refresh = true;
418              LogWarning("SQLiteBatch: Batch closed and failed to abort transaction, resetting db connection..");
419          }
420      }
421  
422      // Free all of the prepared statements
423      const std::vector<std::pair<sqlite3_stmt**, const char*>> statements{
424          {&m_read_stmt, "read"},
425          {&m_insert_stmt, "insert"},
426          {&m_overwrite_stmt, "overwrite"},
427          {&m_delete_stmt, "delete"},
428          {&m_delete_prefix_stmt, "delete prefix"},
429      };
430  
431      for (const auto& [stmt_prepared, stmt_description] : statements) {
432          int res = sqlite3_finalize(*stmt_prepared);
433          if (res != SQLITE_OK) {
434              LogWarning("SQLiteBatch: Batch closed but could not finalize %s statement: %s",
435                        stmt_description, sqlite3_errstr(res));
436          }
437          *stmt_prepared = nullptr;
438      }
439  
440      if (force_conn_refresh) {
441          m_database.Close();
442          try {
443              m_database.Open();
444              // If TxnAbort failed and we refreshed the connection, the semaphore was not released, so release it here to avoid deadlocks on future writes.
445              m_database.m_write_semaphore.release();
446          } catch (const std::runtime_error&) {
447              // If open fails, cleanup this object and rethrow the exception
448              m_database.Close();
449              throw;
450          }
451      }
452  }
453  
454  bool SQLiteBatch::ReadKey(DataStream&& key, DataStream& value)
455  {
456      if (!m_database.m_db) return false;
457      assert(m_read_stmt);
458  
459      // Bind: leftmost parameter in statement is index 1
460      if (!BindBlobToStatement(m_read_stmt, 1, key, "key")) return false;
461      int res = sqlite3_step(m_read_stmt);
462      if (res != SQLITE_ROW) {
463          if (res != SQLITE_DONE) {
464              // SQLITE_DONE means "not found", don't log an error in that case.
465              LogWarning("Unable to execute read statement: %s", sqlite3_errstr(res));
466          }
467          sqlite3_clear_bindings(m_read_stmt);
468          sqlite3_reset(m_read_stmt);
469          return false;
470      }
471      // Leftmost column in result is index 0
472      value.clear();
473      value.write(SpanFromBlob(m_read_stmt, 0));
474  
475      sqlite3_clear_bindings(m_read_stmt);
476      sqlite3_reset(m_read_stmt);
477      return true;
478  }
479  
480  bool SQLiteBatch::WriteKey(DataStream&& key, DataStream&& value, bool overwrite)
481  {
482      if (!m_database.m_db) return false;
483      assert(m_insert_stmt && m_overwrite_stmt);
484  
485      sqlite3_stmt* stmt;
486      if (overwrite) {
487          stmt = m_overwrite_stmt;
488      } else {
489          stmt = m_insert_stmt;
490      }
491  
492      // Bind: leftmost parameter in statement is index 1
493      // Insert index 1 is key, 2 is value
494      if (!BindBlobToStatement(stmt, 1, key, "key")) return false;
495      if (!BindBlobToStatement(stmt, 2, value, "value")) return false;
496  
497      // Acquire semaphore if not previously acquired when creating a transaction.
498      if (!m_txn) m_database.m_write_semaphore.acquire();
499  
500      // Execute
501      int res = sqlite3_step(stmt);
502      sqlite3_clear_bindings(stmt);
503      sqlite3_reset(stmt);
504      if (res != SQLITE_DONE) {
505          LogWarning("Unable to execute write statement: %s", sqlite3_errstr(res));
506      }
507  
508      if (!m_txn) m_database.m_write_semaphore.release();
509  
510      return res == SQLITE_DONE;
511  }
512  
513  bool SQLiteBatch::ExecStatement(sqlite3_stmt* stmt, std::span<const std::byte> blob)
514  {
515      if (!m_database.m_db) return false;
516      assert(stmt);
517  
518      // Bind: leftmost parameter in statement is index 1
519      if (!BindBlobToStatement(stmt, 1, blob, "key")) return false;
520  
521      // Acquire semaphore if not previously acquired when creating a transaction.
522      if (!m_txn) m_database.m_write_semaphore.acquire();
523  
524      // Execute
525      int res = sqlite3_step(stmt);
526      sqlite3_clear_bindings(stmt);
527      sqlite3_reset(stmt);
528      if (res != SQLITE_DONE) {
529          LogWarning("Unable to execute exec statement: %s", sqlite3_errstr(res));
530      }
531  
532      if (!m_txn) m_database.m_write_semaphore.release();
533  
534      return res == SQLITE_DONE;
535  }
536  
537  bool SQLiteBatch::EraseKey(DataStream&& key)
538  {
539      return ExecStatement(m_delete_stmt, key);
540  }
541  
542  bool SQLiteBatch::ErasePrefix(std::span<const std::byte> prefix)
543  {
544      return ExecStatement(m_delete_prefix_stmt, prefix);
545  }
546  
547  bool SQLiteBatch::HasKey(DataStream&& key)
548  {
549      if (!m_database.m_db) return false;
550      assert(m_read_stmt);
551  
552      // Bind: leftmost parameter in statement is index 1
553      if (!BindBlobToStatement(m_read_stmt, 1, key, "key")) return false;
554      int res = sqlite3_step(m_read_stmt);
555      sqlite3_clear_bindings(m_read_stmt);
556      sqlite3_reset(m_read_stmt);
557      return res == SQLITE_ROW;
558  }
559  
560  DatabaseCursor::Status SQLiteCursor::Next(DataStream& key, DataStream& value)
561  {
562      int res = sqlite3_step(m_cursor_stmt);
563      if (res == SQLITE_DONE) {
564          return Status::DONE;
565      }
566      if (res != SQLITE_ROW) {
567          LogWarning("Unable to execute cursor step: %s", sqlite3_errstr(res));
568          return Status::FAIL;
569      }
570  
571      key.clear();
572      value.clear();
573  
574      // Leftmost column in result is index 0
575      key.write(SpanFromBlob(m_cursor_stmt, 0));
576      value.write(SpanFromBlob(m_cursor_stmt, 1));
577      return Status::MORE;
578  }
579  
580  SQLiteCursor::~SQLiteCursor()
581  {
582      sqlite3_clear_bindings(m_cursor_stmt);
583      sqlite3_reset(m_cursor_stmt);
584      int res = sqlite3_finalize(m_cursor_stmt);
585      if (res != SQLITE_OK) {
586          LogWarning("Cursor closed but could not finalize cursor statement: %s",
587                     sqlite3_errstr(res));
588      }
589  }
590  
591  std::unique_ptr<DatabaseCursor> SQLiteBatch::GetNewCursor()
592  {
593      if (!m_database.m_db) return nullptr;
594      auto cursor = std::make_unique<SQLiteCursor>();
595  
596      const char* stmt_text = "SELECT key, value FROM main";
597      int res = sqlite3_prepare_v2(m_database.m_db, stmt_text, -1, &cursor->m_cursor_stmt, nullptr);
598      if (res != SQLITE_OK) {
599          throw std::runtime_error(strprintf(
600              "%s: Failed to setup cursor SQL statement: %s\n", __func__, sqlite3_errstr(res)));
601      }
602  
603      return cursor;
604  }
605  
606  std::unique_ptr<DatabaseCursor> SQLiteBatch::GetNewPrefixCursor(std::span<const std::byte> prefix)
607  {
608      if (!m_database.m_db) return nullptr;
609  
610      // To get just the records we want, the SQL statement does a comparison of the binary data
611      // where the data must be greater than or equal to the prefix, and less than
612      // the prefix incremented by one (when interpreted as an integer)
613      std::vector<std::byte> start_range(prefix.begin(), prefix.end());
614      std::vector<std::byte> end_range(prefix.begin(), prefix.end());
615      auto it = end_range.rbegin();
616      for (; it != end_range.rend(); ++it) {
617          if (*it == std::byte(std::numeric_limits<unsigned char>::max())) {
618              *it = std::byte(0);
619              continue;
620          }
621          *it = std::byte(std::to_integer<unsigned char>(*it) + 1);
622          break;
623      }
624      if (it == end_range.rend()) {
625          // If the prefix is all 0xff bytes, clear end_range as we won't need it
626          end_range.clear();
627      }
628  
629      auto cursor = std::make_unique<SQLiteCursor>(start_range, end_range);
630      if (!cursor) return nullptr;
631  
632      const char* stmt_text = end_range.empty() ? "SELECT key, value FROM main WHERE key >= ?" :
633                              "SELECT key, value FROM main WHERE key >= ? AND key < ?";
634      int res = sqlite3_prepare_v2(m_database.m_db, stmt_text, -1, &cursor->m_cursor_stmt, nullptr);
635      if (res != SQLITE_OK) {
636          throw std::runtime_error(strprintf(
637              "SQLiteDatabase: Failed to setup cursor SQL statement: %s\n", sqlite3_errstr(res)));
638      }
639  
640      if (!BindBlobToStatement(cursor->m_cursor_stmt, 1, cursor->m_prefix_range_start, "prefix_start")) return nullptr;
641      if (!end_range.empty()) {
642          if (!BindBlobToStatement(cursor->m_cursor_stmt, 2, cursor->m_prefix_range_end, "prefix_end")) return nullptr;
643      }
644  
645      return cursor;
646  }
647  
648  bool SQLiteBatch::TxnBegin()
649  {
650      if (!m_database.m_db || m_txn) return false;
651      m_database.m_write_semaphore.acquire();
652      Assert(!m_database.HasActiveTxn());
653      int res = Assert(m_exec_handler)->Exec(m_database, "BEGIN TRANSACTION");
654      if (res != SQLITE_OK) {
655          LogWarning("SQLiteBatch: Failed to begin the transaction");
656          m_database.m_write_semaphore.release();
657      } else {
658          m_txn = true;
659      }
660      return res == SQLITE_OK;
661  }
662  
663  bool SQLiteBatch::TxnCommit()
664  {
665      if (!m_database.m_db || !m_txn) return false;
666      Assert(m_database.HasActiveTxn());
667      int res = Assert(m_exec_handler)->Exec(m_database, "COMMIT TRANSACTION");
668      if (res != SQLITE_OK) {
669          LogWarning("SQLiteBatch: Failed to commit the transaction");
670      } else {
671          m_txn = false;
672          m_database.m_write_semaphore.release();
673      }
674      return res == SQLITE_OK;
675  }
676  
677  bool SQLiteBatch::TxnAbort()
678  {
679      if (!m_database.m_db || !m_txn) return false;
680      Assert(m_database.HasActiveTxn());
681      int res = Assert(m_exec_handler)->Exec(m_database, "ROLLBACK TRANSACTION");
682      if (res != SQLITE_OK) {
683          LogWarning("SQLiteBatch: Failed to abort the transaction");
684      } else {
685          m_txn = false;
686          m_database.m_write_semaphore.release();
687      }
688      return res == SQLITE_OK;
689  }
690  
691  std::unique_ptr<SQLiteDatabase> MakeSQLiteDatabase(const fs::path& path, const DatabaseOptions& options, DatabaseStatus& status, bilingual_str& error)
692  {
693      try {
694          fs::path data_file = SQLiteDataFile(path);
695          auto db = std::make_unique<SQLiteDatabase>(data_file.parent_path(), data_file, options);
696          if (options.verify && !db->Verify(error)) {
697              status = DatabaseStatus::FAILED_VERIFY;
698              return nullptr;
699          }
700          status = DatabaseStatus::SUCCESS;
701          return db;
702      } catch (const std::runtime_error& e) {
703          status = DatabaseStatus::FAILED_LOAD;
704          error = Untranslated(e.what());
705          return nullptr;
706      }
707  }
708  
709  std::string SQLiteDatabaseVersion()
710  {
711      return std::string(sqlite3_libversion());
712  }
713  } // namespace wallet