aboutsummaryrefslogtreecommitdiff
path: root/src/wallet/bdb.h
blob: 82ad136649e3b73a3ccbaa700aace36593b17786 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_WALLET_BDB_H
#define BITCOIN_WALLET_BDB_H

#include <clientversion.h>
#include <fs.h>
#include <serialize.h>
#include <streams.h>
#include <util/system.h>
#include <wallet/db.h>

#include <atomic>
#include <map>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>

#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsuggest-override"
#endif
#include <db_cxx.h>
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic pop
#endif

struct bilingual_str;

static const unsigned int DEFAULT_WALLET_DBLOGSIZE = 100;
static const bool DEFAULT_WALLET_PRIVDB = true;

struct WalletDatabaseFileId {
    u_int8_t value[DB_FILE_ID_LEN];
    bool operator==(const WalletDatabaseFileId& rhs) const;
};

class BerkeleyDatabase;

class BerkeleyEnvironment
{
private:
    bool fDbEnvInit;
    bool fMockDb;
    // Don't change into fs::path, as that can result in
    // shutdown problems/crashes caused by a static initialized internal pointer.
    std::string strPath;

public:
    std::unique_ptr<DbEnv> dbenv;
    std::map<std::string, std::reference_wrapper<BerkeleyDatabase>> m_databases;
    std::unordered_map<std::string, WalletDatabaseFileId> m_fileids;
    std::condition_variable_any m_db_in_use;

    BerkeleyEnvironment(const fs::path& env_directory);
    BerkeleyEnvironment();
    ~BerkeleyEnvironment();
    void Reset();

    bool IsMock() const { return fMockDb; }
    bool IsInitialized() const { return fDbEnvInit; }
    bool IsDatabaseLoaded(const std::string& db_filename) const { return m_databases.find(db_filename) != m_databases.end(); }
    fs::path Directory() const { return strPath; }

    bool Open(bilingual_str& error);
    void Close();
    void Flush(bool fShutdown);
    void CheckpointLSN(const std::string& strFile);

    void CloseDb(const std::string& strFile);
    void ReloadDbEnv();

    DbTxn* TxnBegin(int flags = DB_TXN_WRITE_NOSYNC)
    {
        DbTxn* ptxn = nullptr;
        int ret = dbenv->txn_begin(nullptr, &ptxn, flags);
        if (!ptxn || ret != 0)
            return nullptr;
        return ptxn;
    }
};

/** Get BerkeleyEnvironment and database filename given a wallet path. */
std::shared_ptr<BerkeleyEnvironment> GetWalletEnv(const fs::path& wallet_path, std::string& database_filename);

/** Return whether a BDB wallet database is currently loaded. */
bool IsBDBWalletLoaded(const fs::path& wallet_path);

/** Check format of database file */
bool IsBerkeleyBtree(const fs::path& path);

class BerkeleyBatch;

/** An instance of this class represents one database.
 * For BerkeleyDB this is just a (env, strFile) tuple.
 **/
class BerkeleyDatabase : public WalletDatabase
{
public:
    BerkeleyDatabase() = delete;

    /** Create DB handle to real database */
    BerkeleyDatabase(std::shared_ptr<BerkeleyEnvironment> env, std::string filename) :
        WalletDatabase(), env(std::move(env)), strFile(std::move(filename))
    {
        auto inserted = this->env->m_databases.emplace(strFile, std::ref(*this));
        assert(inserted.second);
    }

    ~BerkeleyDatabase() override;

    /** Open the database if it is not already opened.
     *  Dummy function, doesn't do anything right now, but is needed for class abstraction */
    void Open(const char* mode) override;

    /** Rewrite the entire database on disk, with the exception of key pszSkip if non-zero
     */
    bool Rewrite(const char* pszSkip=nullptr) override;

    /** Indicate the a new database user has began using the database. */
    void AddRef() override;
    /** Indicate that database user has stopped using the database and that it could be flushed or closed. */
    void RemoveRef() override;

    /** Back up the entire database to a file.
     */
    bool Backup(const std::string& strDest) const override;

    /** Make sure all changes are flushed to database file.
     */
    void Flush() override;
    /** Flush to the database file and close the database.
     *  Also close the environment if no other databases are open in it.
     */
    void Close() override;
    /* flush the wallet passively (TRY_LOCK)
       ideal to be called periodically */
    bool PeriodicFlush() override;

    void IncrementUpdateCounter() override;

    void ReloadDbEnv() override;

    /** Verifies the environment and database file */
    bool Verify(bilingual_str& error) override;

    /**
     * Pointer to shared database environment.
     *
     * Normally there is only one BerkeleyDatabase object per
     * BerkeleyEnvivonment, but in the special, backwards compatible case where
     * multiple wallet BDB data files are loaded from the same directory, this
     * will point to a shared instance that gets freed when the last data file
     * is closed.
     */
    std::shared_ptr<BerkeleyEnvironment> env;

    /** Database pointer. This is initialized lazily and reset during flushes, so it can be null. */
    std::unique_ptr<Db> m_db;

    std::string strFile;

    /** Make a BerkeleyBatch connected to this database */
    std::unique_ptr<DatabaseBatch> MakeBatch(const char* mode = "r+", bool flush_on_close = true) override;
};

/** RAII class that provides access to a Berkeley database */
class BerkeleyBatch : public DatabaseBatch
{
    /** RAII class that automatically cleanses its data on destruction */
    class SafeDbt final
    {
        Dbt m_dbt;

    public:
        // construct Dbt with internally-managed data
        SafeDbt();
        // construct Dbt with provided data
        SafeDbt(void* data, size_t size);
        ~SafeDbt();

        // delegate to Dbt
        const void* get_data() const;
        u_int32_t get_size() const;

        // conversion operator to access the underlying Dbt
        operator Dbt*();
    };

private:
    bool ReadKey(CDataStream&& key, CDataStream& value) override;
    bool WriteKey(CDataStream&& key, CDataStream&& value, bool overwrite = true) override;
    bool EraseKey(CDataStream&& key) override;
    bool HasKey(CDataStream&& key) override;

protected:
    Db* pdb;
    std::string strFile;
    DbTxn* activeTxn;
    Dbc* m_cursor;
    bool fReadOnly;
    bool fFlushOnClose;
    BerkeleyEnvironment *env;
    BerkeleyDatabase& m_database;

public:
    explicit BerkeleyBatch(BerkeleyDatabase& database, const char* pszMode = "r+", bool fFlushOnCloseIn=true);
    ~BerkeleyBatch() override;

    BerkeleyBatch(const BerkeleyBatch&) = delete;
    BerkeleyBatch& operator=(const BerkeleyBatch&) = delete;

    void Flush() override;
    void Close() override;

    bool StartCursor() override;
    bool ReadAtCursor(CDataStream& ssKey, CDataStream& ssValue, bool& complete) override;
    void CloseCursor() override;
    bool TxnBegin() override;
    bool TxnCommit() override;
    bool TxnAbort() override;
};

std::string BerkeleyDatabaseVersion();

//! Check if Berkeley database exists at specified path.
bool ExistsBerkeleyDatabase(const fs::path& path);

//! Return object giving access to Berkeley database at specified path.
std::unique_ptr<BerkeleyDatabase> MakeBerkeleyDatabase(const fs::path& path, const DatabaseOptions& options, DatabaseStatus& status, bilingual_str& error);

#endif // BITCOIN_WALLET_BDB_H