1// Copyright (c) 2009-2010 Satoshi Nakamoto
2// Copyright (c) 2009-present 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 <util/fs.h>
9#include <util/log.h>
10#include <wallet/db.h>
11
12#include <algorithm>
13#include <exception>
14#include <fstream>
15#include <string>
16#include <system_error>
17#include <vector>
18
19namespace wallet {
20bool operator<(BytePrefix a, std::span<const std::byte> b) { return std::ranges::lexicographical_compare(a.prefix, b.subspan(0, std::min(a.prefix.size(), b.size()))); }
21bool operator<(std::span<const std::byte> a, BytePrefix b) { return std::ranges::lexicographical_compare(a.subspan(0, std::min(a.size(), b.prefix.size())), b.prefix); }
22
23std::vector<std::pair<fs::path, std::string>> ListDatabases(const fs::path& wallet_dir)
24{
25    std::vector<std::pair<fs::path, std::string>> paths;
26    std::error_code ec;
27
28    for (auto it = fs::recursive_directory_iterator(wallet_dir, ec); it != fs::recursive_directory_iterator(); it.increment(ec)) {
29        assert(!ec); // Loop should exit on error.
30        try {
31            const fs::path path{it->path().lexically_relative(wallet_dir)};
32
33            if (it->status().type() == fs::file_type::directory) {
34                if (IsBDBFile(BDBDataFile(it->path()))) {
35                    // Found a directory which contains wallet.dat btree file, add it as a wallet with BERKELEY format.
36                    paths.emplace_back(path, "bdb");
37                } else if (IsSQLiteFile(SQLiteDataFile(it->path()))) {
38                    // Found a directory which contains wallet.dat sqlite file, add it as a wallet with SQLITE format.
39                    paths.emplace_back(path, "sqlite");
40                }
41            } else if (it.depth() == 0 && it->symlink_status().type() == fs::file_type::regular && it->path().extension() != ".bak") {
42                if (it->path().filename() == "wallet.dat") {
43                    // Found top-level wallet.dat file, add top level directory ""
44                    // as a wallet.
45                    if (IsBDBFile(it->path())) {
46                        paths.emplace_back(fs::path(), "bdb");
47                    } else if (IsSQLiteFile(it->path())) {
48                        paths.emplace_back(fs::path(), "sqlite");
49                    }
50                } else if (IsBDBFile(it->path())) {
51                    // Found top-level btree file not called wallet.dat. Current bitcoin
52                    // software will never create these files but will allow them to be
53                    // opened in a shared database environment for backwards compatibility.
54                    // Add it to the list of available wallets.
55                    paths.emplace_back(path, "bdb");
56                }
57            }
58        } catch (const std::exception& e) {
59            LogWarning("Error while scanning wallet dir item: %s [%s].", e.what(), fs::PathToString(it->path()));
60            it.disable_recursion_pending();
61        }
62    }
63    if (ec) {
64        // Loop could have exited with an error due to one of:
65        // * wallet_dir itself not being scannable.
66        // * increment() failure. (Observed on Windows native builds when
67        //   removing the ACL read permissions of a wallet directory after the
68        //   process started).
69        LogWarning("Error scanning directory entries under %s: %s", fs::PathToString(wallet_dir), ec.message());
70    }
71
72    return paths;
73}
74
75fs::path BDBDataFile(const fs::path& wallet_path)
76{
77    if (fs::is_regular_file(wallet_path)) {
78        // Special case for backwards compatibility: if wallet path points to an
79        // existing file, treat it as the path to a BDB data file in a parent
80        // directory that also contains BDB log files.
81        return wallet_path;
82    } else {
83        // Normal case: Interpret wallet path as a directory path containing
84        // data and log files.
85        return wallet_path / "wallet.dat";
86    }
87}
88
89fs::path SQLiteDataFile(const fs::path& path)
90{
91    return path / "wallet.dat";
92}
93
94bool IsBDBFile(const fs::path& path)
95{
96    if (!fs::exists(path)) return false;
97
98    // A Berkeley DB Btree file has at least 4K.
99    // This check also prevents opening lock files.
100    std::error_code ec;
101    auto size = fs::file_size(path, ec);
102    if (ec) LogWarning("Error reading file_size: %s [%s]", ec.message(), fs::PathToString(path));
103    if (size < 4096) return false;
104
105    std::ifstream file{path.std_path(), std::ios::binary};
106    if (!file.is_open()) return false;
107
108    file.seekg(12, std::ios::beg); // Magic bytes start at offset 12
109    uint32_t data = 0;
110    file.read((char*) &data, sizeof(data)); // Read 4 bytes of file to compare against magic
111
112    // Berkeley DB Btree magic bytes, from:
113    //  https://github.com/file/file/blob/5824af38469ec1ca9ac3ffd251e7afe9dc11e227/magic/Magdir/database#L74-L75
114    //  - big endian systems - 00 05 31 62
115    //  - little endian systems - 62 31 05 00
116    return data == 0x00053162 || data == 0x62310500;
117}
118
119bool IsSQLiteFile(const fs::path& path)
120{
121    if (!fs::exists(path)) return false;
122
123    // A SQLite Database file is at least 512 bytes.
124    std::error_code ec;
125    auto size = fs::file_size(path, ec);
126    if (ec) LogWarning("Error reading file_size: %s [%s]", ec.message(), fs::PathToString(path));
127    if (size < 512) return false;
128
129    std::ifstream file{path.std_path(), std::ios::binary};
130    if (!file.is_open()) return false;
131
132    // Magic is at beginning and is 16 bytes long
133    char magic[16];
134    file.read(magic, 16);
135
136    // Application id is at offset 68 and 4 bytes long
137    file.seekg(68, std::ios::beg);
138    char app_id[4];
139    file.read(app_id, 4);
140
141    file.close();
142
143    // Check the magic, see https://sqlite.org/fileformat.html
144    std::string magic_str(magic, 16);
145    if (magic_str != std::string{"SQLite format 3\000", 16}) {
146        return false;
147    }
148
149    // Check the application id matches our network magic
150    return memcmp(Params().MessageStart().data(), app_id, 4) == 0;
151}
152
153void ReadDatabaseArgs(const ArgsManager& args, DatabaseOptions& options)
154{
155    // Override current options with args values, if any were specified
156    options.use_unsafe_sync = args.GetBoolArg("-unsafesqlitesync", options.use_unsafe_sync);
157}
158
159} // namespace wallet
160