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dbwrapper.cpp
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// Copyright (c) 2012-2015 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "dbwrapper.h"
#include "util.h"
#include "random.h"
#include <boost/filesystem.hpp>
#include <leveldb/cache.h>
#include <leveldb/env.h>
#include <leveldb/filter_policy.h>
#include <memenv.h>
#include <stdint.h>
static leveldb::Options GetOptions(size_t nCacheSize)
{
leveldb::Options options;
options.block_cache = leveldb::NewLRUCache(nCacheSize / 2);
options.write_buffer_size = nCacheSize / 4; // up to two write buffers may be held in memory simultaneously
options.filter_policy = leveldb::NewBloomFilterPolicy(10);
options.compression = leveldb::kNoCompression;
options.max_open_files = 64;
if (leveldb::kMajorVersion > 1 || (leveldb::kMajorVersion == 1 && leveldb::kMinorVersion >= 16)) {
// LevelDB versions before 1.16 consider short writes to be corruption. Only trigger error
// on corruption in later versions.
options.paranoid_checks = true;
}
return options;
}
CDBWrapper::CDBWrapper(const boost::filesystem::path& path, size_t nCacheSize, bool fMemory, bool fWipe, bool obfuscate)
{
penv = NULL;
readoptions.verify_checksums = true;
iteroptions.verify_checksums = true;
iteroptions.fill_cache = false;
syncoptions.sync = true;
options = GetOptions(nCacheSize);
options.create_if_missing = true;
if (fMemory) {
penv = leveldb::NewMemEnv(leveldb::Env::Default());
options.env = penv;
} else {
if (fWipe) {
LogPrintf("Wiping LevelDB in %s\n", path.string());
leveldb::Status result = leveldb::DestroyDB(path.string(), options);
dbwrapper_private::HandleError(result);
}
TryCreateDirectory(path);
LogPrintf("Opening LevelDB in %s\n", path.string());
}
leveldb::Status status = leveldb::DB::Open(options, path.string(), &pdb);
dbwrapper_private::HandleError(status);
LogPrintf("Opened LevelDB successfully\n");
// The base-case obfuscation key, which is a noop.
obfuscate_key = std::vector<unsigned char>(OBFUSCATE_KEY_NUM_BYTES, '\000');
bool key_exists = Read(OBFUSCATE_KEY_KEY, obfuscate_key);
if (!key_exists && obfuscate && IsEmpty()) {
// Initialize non-degenerate obfuscation if it won't upset
// existing, non-obfuscated data.
std::vector<unsigned char> new_key = CreateObfuscateKey();
// Write `new_key` so we don't obfuscate the key with itself
Write(OBFUSCATE_KEY_KEY, new_key);
obfuscate_key = new_key;
LogPrintf("Wrote new obfuscate key for %s: %s\n", path.string(), HexStr(obfuscate_key));
}
LogPrintf("Using obfuscation key for %s: %s\n", path.string(), HexStr(obfuscate_key));
}
CDBWrapper::~CDBWrapper()
{
delete pdb;
pdb = NULL;
delete options.filter_policy;
options.filter_policy = NULL;
delete options.block_cache;
options.block_cache = NULL;
delete penv;
options.env = NULL;
}
bool CDBWrapper::WriteBatch(CDBBatch& batch, bool fSync)
{
leveldb::Status status = pdb->Write(fSync ? syncoptions : writeoptions, &batch.batch);
dbwrapper_private::HandleError(status);
return true;
}
// Prefixed with null character to avoid collisions with other keys
//
// We must use a string constructor which specifies length so that we copy
// past the null-terminator.
const std::string CDBWrapper::OBFUSCATE_KEY_KEY("\000obfuscate_key", 14);
const unsigned int CDBWrapper::OBFUSCATE_KEY_NUM_BYTES = 8;
/**
* Returns a string (consisting of 8 random bytes) suitable for use as an
* obfuscating XOR key.
*/
std::vector<unsigned char> CDBWrapper::CreateObfuscateKey() const
{
unsigned char buff[OBFUSCATE_KEY_NUM_BYTES];
GetRandBytes(buff, OBFUSCATE_KEY_NUM_BYTES);
return std::vector<unsigned char>(&buff[0], &buff[OBFUSCATE_KEY_NUM_BYTES]);
}
bool CDBWrapper::IsEmpty()
{
std::unique_ptr<CDBIterator> it(NewIterator());
it->SeekToFirst();
return !(it->Valid());
}
CDBIterator::~CDBIterator() { delete piter; }
bool CDBIterator::Valid() { return piter->Valid(); }
void CDBIterator::SeekToFirst() { piter->SeekToFirst(); }
void CDBIterator::Next() { piter->Next(); }
namespace dbwrapper_private {
void HandleError(const leveldb::Status& status)
{
if (status.ok())
return;
LogPrintf("%s\n", status.ToString());
if (status.IsCorruption())
throw dbwrapper_error("Database corrupted");
if (status.IsIOError())
throw dbwrapper_error("Database I/O error");
if (status.IsNotFound())
throw dbwrapper_error("Database entry missing");
throw dbwrapper_error("Unknown database error");
}
const std::vector<unsigned char>& GetObfuscateKey(const CDBWrapper &w)
{
return w.obfuscate_key;
}
};

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