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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 The Starwels developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef STARWELS_WALLET_DB_H
#define STARWELS_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;
std::unique_ptr<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, bool retry = 0);
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 = nullptr;
int ret = dbenv->txn_begin(nullptr, &ptxn, flags);
if (!ptxn || ret != 0)
return nullptr;
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(); }
CDB(const CDB&) = delete;
CDB& operator=(const CDB&) = delete;
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& walletDir, std::string& errorStr);
/* verifies the database file */
static bool VerifyDatabaseFile(const std::string& walletFile, const fs::path& walletDir, std::string& warningStr, std::string& errorStr, CDBEnv::recoverFunc_type recoverFunc);
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() != nullptr) {
// 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 nullptr;
Dbc* pcursor = nullptr;
int ret = pdb->cursor(nullptr, &pcursor, 0);
if (ret != 0)
return nullptr;
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() == nullptr || datValue.get_data() == nullptr)
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 = nullptr;
return (ret == 0);
}
bool TxnAbort()
{
if (!pdb || !activeTxn)
return false;
int ret = activeTxn->abort();
activeTxn = nullptr;
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 = nullptr);
};
#endif // STARWELS_WALLET_DB_H