lbrycrd/src/wallet/db.h
Russell Yanofsky d8a99f65e5 Allow wallet files in multiple directories
Remove requirement that two wallet files can only be opened at the same time if
they are contained in the same directory.

This change mostly consists of updates to function signatures (updating
functions to take fs::path arguments, instead of combinations of strings,
fs::path, and CDBEnv / CWalletDBWrapper arguments).
2018-03-03 10:26:55 -05:00

392 lines
11 KiB
C++

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 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 <util.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;
public:
std::unique_ptr<DbEnv> dbenv;
std::map<std::string, int> mapFileUseCount;
std::map<std::string, Db*> mapDb;
CDBEnv(const fs::path& env_directory);
~CDBEnv();
void Reset();
void MakeMock();
bool IsMock() const { return fMockDb; }
bool IsInitialized() const { return fDbEnvInit; }
fs::path Directory() const { return strPath; }
/**
* 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 fs::path& file_path, 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(bool retry);
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;
}
};
/** Get CDBEnv and database filename given a wallet path. */
CDBEnv* GetWalletEnv(const fs::path& wallet_path, std::string& database_filename);
/** 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(const fs::path& wallet_path, bool mock = false) :
nUpdateCounter(0), nLastSeen(0), nLastFlushed(0), nLastWalletUpdate(0)
{
env = GetWalletEnv(wallet_path, strFile);
if (mock) {
env->Close();
env->Reset();
env->MakeMock();
}
}
/** Return object for accessing database at specified path. */
static std::unique_ptr<CWalletDBWrapper> Create(const fs::path& path)
{
return MakeUnique<CWalletDBWrapper>(path);
}
/** Return object for accessing dummy database with no read/write capabilities. */
static std::unique_ptr<CWalletDBWrapper> CreateDummy()
{
return MakeUnique<CWalletDBWrapper>();
}
/** Return object for accessing temporary in-memory database. */
static std::unique_ptr<CWalletDBWrapper> CreateMock()
{
return MakeUnique<CWalletDBWrapper>("", true /* mock */);
}
/** 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);
/** 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 fs::path& file_path, 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 fs::path& file_path, std::string& errorStr);
/* verifies the database file */
static bool VerifyDatabaseFile(const fs::path& file_path, 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 = env->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 // BITCOIN_WALLET_DB_H