aboutsummaryrefslogtreecommitdiff
path: root/src/wallet/db.h
blob: 0ebbaadccee2373f792478c1cad23319dd2ad717 (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
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 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_DB_H
#define BITCOIN_WALLET_DB_H

#include "clientversion.h"
#include "fs.h"
#include "serialize.h"
#include "streams.h"
#include "sync.h"
#include "version.h"

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

#include <db_cxx.h>

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

class CDBEnv
{
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;

    void EnvShutdown();

public:
    mutable CCriticalSection cs_db;
    DbEnv *dbenv;
    std::map<std::string, int> mapFileUseCount;
    std::map<std::string, Db*> mapDb;

    CDBEnv();
    ~CDBEnv();
    void Reset();

    void MakeMock();
    bool IsMock() const { return fMockDb; }

    /**
     * Verify that database file strFile is OK. If it is not,
     * call the callback to try to recover.
     * This must be called BEFORE strFile is opened.
     * Returns true if strFile is OK.
     */
    enum VerifyResult { VERIFY_OK,
                        RECOVER_OK,
                        RECOVER_FAIL };
    typedef bool (*recoverFunc_type)(const std::string& strFile, std::string& out_backup_filename);
    VerifyResult Verify(const std::string& strFile, recoverFunc_type recoverFunc, std::string& out_backup_filename);
    /**
     * Salvage data from a file that Verify says is bad.
     * fAggressive sets the DB_AGGRESSIVE flag (see berkeley DB->verify() method documentation).
     * Appends binary key/value pairs to vResult, returns true if successful.
     * NOTE: reads the entire database into memory, so cannot be used
     * for huge databases.
     */
    typedef std::pair<std::vector<unsigned char>, std::vector<unsigned char> > KeyValPair;
    bool Salvage(const std::string& strFile, bool fAggressive, std::vector<KeyValPair>& vResult);

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

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

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

extern CDBEnv bitdb;

/** An instance of this class represents one database.
 * For BerkeleyDB this is just a (env, strFile) tuple.
 **/
class CWalletDBWrapper
{
    friend class CDB;
public:
    /** Create dummy DB handle */
    CWalletDBWrapper() : nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0), env(nullptr)
    {
    }

    /** Create DB handle to real database */
    CWalletDBWrapper(CDBEnv *env_in, const std::string &strFile_in) :
        nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0), env(env_in), strFile(strFile_in)
    {
    }

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

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

    /** Get a name for this database, for debugging etc.
     */
    std::string GetName() const { return strFile; }

    /** Make sure all changes are flushed to disk.
     */
    void Flush(bool shutdown);

    void IncrementUpdateCounter();

    std::atomic<unsigned int> nUpdateCounter;
    unsigned int nLastSeen;
    unsigned int nLastFlushed;
    int64_t nLastWalletUpdate;

private:
    /** BerkeleyDB specific */
    CDBEnv *env;
    std::string strFile;

    /** Return whether this database handle is a dummy for testing.
     * Only to be used at a low level, application should ideally not care
     * about this.
     */
    bool IsDummy() { return env == nullptr; }
};


/** RAII class that provides access to a Berkeley database */
class CDB
{
protected:
    Db* pdb;
    std::string strFile;
    DbTxn* activeTxn;
    bool fReadOnly;
    bool fFlushOnClose;
    CDBEnv *env;

public:
    explicit CDB(CWalletDBWrapper& dbw, const char* pszMode = "r+", bool fFlushOnCloseIn=true);
    ~CDB() { Close(); }

    void Flush();
    void Close();
    static bool Recover(const std::string& filename, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& out_backup_filename);

    /* flush the wallet passively (TRY_LOCK)
       ideal to be called periodically */
    static bool PeriodicFlush(CWalletDBWrapper& dbw);
    /* verifies the database environment */
    static bool VerifyEnvironment(const std::string& walletFile, const fs::path& dataDir, std::string& errorStr);
    /* verifies the database file */
    static bool VerifyDatabaseFile(const std::string& walletFile, const fs::path& dataDir, std::string& warningStr, std::string& errorStr, CDBEnv::recoverFunc_type recoverFunc);

private:
    CDB(const CDB&);
    void operator=(const CDB&);

public:
    template <typename K, typename T>
    bool Read(const K& key, T& value)
    {
        if (!pdb)
            return false;

        // Key
        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(ssKey.data(), ssKey.size());

        // Read
        Dbt datValue;
        datValue.set_flags(DB_DBT_MALLOC);
        int ret = pdb->get(activeTxn, &datKey, &datValue, 0);
        memory_cleanse(datKey.get_data(), datKey.get_size());
        bool success = false;
        if (datValue.get_data() != NULL) {
            // Unserialize value
            try {
                CDataStream ssValue((char*)datValue.get_data(), (char*)datValue.get_data() + datValue.get_size(), SER_DISK, CLIENT_VERSION);
                ssValue >> value;
                success = true;
            } catch (const std::exception&) {
                // In this case success remains 'false'
            }

            // Clear and free memory
            memory_cleanse(datValue.get_data(), datValue.get_size());
            free(datValue.get_data());
        }
        return ret == 0 && success;
    }

    template <typename K, typename T>
    bool Write(const K& key, const T& value, bool fOverwrite = true)
    {
        if (!pdb)
            return true;
        if (fReadOnly)
            assert(!"Write called on database in read-only mode");

        // Key
        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(ssKey.data(), ssKey.size());

        // Value
        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
        ssValue.reserve(10000);
        ssValue << value;
        Dbt datValue(ssValue.data(), ssValue.size());

        // Write
        int ret = pdb->put(activeTxn, &datKey, &datValue, (fOverwrite ? 0 : DB_NOOVERWRITE));

        // Clear memory in case it was a private key
        memory_cleanse(datKey.get_data(), datKey.get_size());
        memory_cleanse(datValue.get_data(), datValue.get_size());
        return (ret == 0);
    }

    template <typename K>
    bool Erase(const K& key)
    {
        if (!pdb)
            return false;
        if (fReadOnly)
            assert(!"Erase called on database in read-only mode");

        // Key
        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(ssKey.data(), ssKey.size());

        // Erase
        int ret = pdb->del(activeTxn, &datKey, 0);

        // Clear memory
        memory_cleanse(datKey.get_data(), datKey.get_size());
        return (ret == 0 || ret == DB_NOTFOUND);
    }

    template <typename K>
    bool Exists(const K& key)
    {
        if (!pdb)
            return false;

        // Key
        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
        ssKey.reserve(1000);
        ssKey << key;
        Dbt datKey(ssKey.data(), ssKey.size());

        // Exists
        int ret = pdb->exists(activeTxn, &datKey, 0);

        // Clear memory
        memory_cleanse(datKey.get_data(), datKey.get_size());
        return (ret == 0);
    }

    Dbc* GetCursor()
    {
        if (!pdb)
            return NULL;
        Dbc* pcursor = NULL;
        int ret = pdb->cursor(NULL, &pcursor, 0);
        if (ret != 0)
            return NULL;
        return pcursor;
    }

    int ReadAtCursor(Dbc* pcursor, CDataStream& ssKey, CDataStream& ssValue, bool setRange = false)
    {
        // Read at cursor
        Dbt datKey;
        unsigned int fFlags = DB_NEXT;
        if (setRange) {
            datKey.set_data(ssKey.data());
            datKey.set_size(ssKey.size());
            fFlags = DB_SET_RANGE;
        }
        Dbt datValue;
        datKey.set_flags(DB_DBT_MALLOC);
        datValue.set_flags(DB_DBT_MALLOC);
        int ret = pcursor->get(&datKey, &datValue, fFlags);
        if (ret != 0)
            return ret;
        else if (datKey.get_data() == NULL || datValue.get_data() == NULL)
            return 99999;

        // Convert to streams
        ssKey.SetType(SER_DISK);
        ssKey.clear();
        ssKey.write((char*)datKey.get_data(), datKey.get_size());
        ssValue.SetType(SER_DISK);
        ssValue.clear();
        ssValue.write((char*)datValue.get_data(), datValue.get_size());

        // Clear and free memory
        memory_cleanse(datKey.get_data(), datKey.get_size());
        memory_cleanse(datValue.get_data(), datValue.get_size());
        free(datKey.get_data());
        free(datValue.get_data());
        return 0;
    }

public:
    bool TxnBegin()
    {
        if (!pdb || activeTxn)
            return false;
        DbTxn* ptxn = bitdb.TxnBegin();
        if (!ptxn)
            return false;
        activeTxn = ptxn;
        return true;
    }

    bool TxnCommit()
    {
        if (!pdb || !activeTxn)
            return false;
        int ret = activeTxn->commit(0);
        activeTxn = NULL;
        return (ret == 0);
    }

    bool TxnAbort()
    {
        if (!pdb || !activeTxn)
            return false;
        int ret = activeTxn->abort();
        activeTxn = NULL;
        return (ret == 0);
    }

    bool ReadVersion(int& nVersion)
    {
        nVersion = 0;
        return Read(std::string("version"), nVersion);
    }

    bool WriteVersion(int nVersion)
    {
        return Write(std::string("version"), nVersion);
    }

    bool static Rewrite(CWalletDBWrapper& dbw, const char* pszSkip = NULL);
};

#endif // BITCOIN_WALLET_DB_H