db.cpp
1 // Copyright (c) 2009-2010 Satoshi Nakamoto 2 // Copyright (c) 2009-2021 The Bitcoin Core developers 3 // Distributed under the MIT software license, see the accompanying 4 // file COPYING or http://www.opensource.org/licenses/mit-license.php. 5 6 #include <chainparams.h> 7 #include <common/args.h> 8 #include <logging.h> 9 #include <util/fs.h> 10 #include <wallet/db.h> 11 12 #include <exception> 13 #include <fstream> 14 #include <string> 15 #include <system_error> 16 #include <vector> 17 18 namespace wallet { 19 std::vector<fs::path> ListDatabases(const fs::path& wallet_dir) 20 { 21 std::vector<fs::path> paths; 22 std::error_code ec; 23 24 for (auto it = fs::recursive_directory_iterator(wallet_dir, ec); it != fs::recursive_directory_iterator(); it.increment(ec)) { 25 if (ec) { 26 if (fs::is_directory(*it)) { 27 it.disable_recursion_pending(); 28 LogPrintf("%s: %s %s -- skipping.\n", __func__, ec.message(), fs::PathToString(it->path())); 29 } else { 30 LogPrintf("%s: %s %s\n", __func__, ec.message(), fs::PathToString(it->path())); 31 } 32 continue; 33 } 34 35 try { 36 const fs::path path{it->path().lexically_relative(wallet_dir)}; 37 38 if (it->status().type() == fs::file_type::directory && 39 (IsBDBFile(BDBDataFile(it->path())) || IsSQLiteFile(SQLiteDataFile(it->path())))) { 40 // Found a directory which contains wallet.dat btree file, add it as a wallet. 41 paths.emplace_back(path); 42 } else if (it.depth() == 0 && it->symlink_status().type() == fs::file_type::regular && IsBDBFile(it->path())) { 43 if (it->path().filename() == "wallet.dat") { 44 // Found top-level wallet.dat btree file, add top level directory "" 45 // as a wallet. 46 paths.emplace_back(); 47 } else { 48 // Found top-level btree file not called wallet.dat. Current bitcoin 49 // software will never create these files but will allow them to be 50 // opened in a shared database environment for backwards compatibility. 51 // Add it to the list of available wallets. 52 paths.emplace_back(path); 53 } 54 } 55 } catch (const std::exception& e) { 56 LogPrintf("%s: Error scanning %s: %s\n", __func__, fs::PathToString(it->path()), e.what()); 57 it.disable_recursion_pending(); 58 } 59 } 60 61 return paths; 62 } 63 64 fs::path BDBDataFile(const fs::path& wallet_path) 65 { 66 if (fs::is_regular_file(wallet_path)) { 67 // Special case for backwards compatibility: if wallet path points to an 68 // existing file, treat it as the path to a BDB data file in a parent 69 // directory that also contains BDB log files. 70 return wallet_path; 71 } else { 72 // Normal case: Interpret wallet path as a directory path containing 73 // data and log files. 74 return wallet_path / "wallet.dat"; 75 } 76 } 77 78 fs::path SQLiteDataFile(const fs::path& path) 79 { 80 return path / "wallet.dat"; 81 } 82 83 bool IsBDBFile(const fs::path& path) 84 { 85 if (!fs::exists(path)) return false; 86 87 // A Berkeley DB Btree file has at least 4K. 88 // This check also prevents opening lock files. 89 std::error_code ec; 90 auto size = fs::file_size(path, ec); 91 if (ec) LogPrintf("%s: %s %s\n", __func__, ec.message(), fs::PathToString(path)); 92 if (size < 4096) return false; 93 94 std::ifstream file{path, std::ios::binary}; 95 if (!file.is_open()) return false; 96 97 file.seekg(12, std::ios::beg); // Magic bytes start at offset 12 98 uint32_t data = 0; 99 file.read((char*) &data, sizeof(data)); // Read 4 bytes of file to compare against magic 100 101 // Berkeley DB Btree magic bytes, from: 102 // https://github.com/file/file/blob/5824af38469ec1ca9ac3ffd251e7afe9dc11e227/magic/Magdir/database#L74-L75 103 // - big endian systems - 00 05 31 62 104 // - little endian systems - 62 31 05 00 105 return data == 0x00053162 || data == 0x62310500; 106 } 107 108 bool IsSQLiteFile(const fs::path& path) 109 { 110 if (!fs::exists(path)) return false; 111 112 // A SQLite Database file is at least 512 bytes. 113 std::error_code ec; 114 auto size = fs::file_size(path, ec); 115 if (ec) LogPrintf("%s: %s %s\n", __func__, ec.message(), fs::PathToString(path)); 116 if (size < 512) return false; 117 118 std::ifstream file{path, std::ios::binary}; 119 if (!file.is_open()) return false; 120 121 // Magic is at beginning and is 16 bytes long 122 char magic[16]; 123 file.read(magic, 16); 124 125 // Application id is at offset 68 and 4 bytes long 126 file.seekg(68, std::ios::beg); 127 char app_id[4]; 128 file.read(app_id, 4); 129 130 file.close(); 131 132 // Check the magic, see https://sqlite.org/fileformat.html 133 std::string magic_str(magic, 16); 134 if (magic_str != std::string{"SQLite format 3\000", 16}) { 135 return false; 136 } 137 138 // Check the application id matches our network magic 139 return memcmp(Params().MessageStart().data(), app_id, 4) == 0; 140 } 141 142 void ReadDatabaseArgs(const ArgsManager& args, DatabaseOptions& options) 143 { 144 // Override current options with args values, if any were specified 145 options.use_unsafe_sync = args.GetBoolArg("-unsafesqlitesync", options.use_unsafe_sync); 146 options.use_shared_memory = !args.GetBoolArg("-privdb", !options.use_shared_memory); 147 options.max_log_mb = args.GetIntArg("-dblogsize", options.max_log_mb); 148 } 149 150 } // namespace wallet