fuzz coverage

// Copyright (c) 2009-2010 Satoshi Nakamoto

// Copyright (c) 2009-present 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 <common/system.h>

#include <serialize.h>

#include <streams.h>

#include <util/fs.h>

#include <wallet/db.h>

#include <atomic>

#include <condition_variable>

#include <map>

#include <memory>

#include <string>

#include <unordered_map>

#include <vector>

struct bilingual_str;

class DbEnv;

class DbTxn;

class Db;

class Dbc;

// This constant was introduced in BDB 4.0.14 and has never changed, but there

// is a belt-and-suspenders check in the cpp file just in case.

#define BDB_DB_FILE_ID_LEN 20 /* Unique file ID length. */

namespace wallet {

struct WalletDatabaseFileId {

    uint8_t value[BDB_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<fs::path, std::reference_wrapper<BerkeleyDatabase>> m_databases;

    std::unordered_map<std::string, WalletDatabaseFileId> m_fileids;

    std::condition_variable_any m_db_in_use;

    bool m_use_shared_memory;

    explicit BerkeleyEnvironment(const fs::path& env_directory, bool use_shared_memory);

    BerkeleyEnvironment();

    ~BerkeleyEnvironment();

    void Reset();

    bool IsMock() const { return fMockDb; }

    bool IsInitialized() const { return fDbEnvInit; }

    fs::path Directory() const { return fs::PathFromString(strPath); }

    bool Open(bilingual_str& error);

    void Close();

    void Flush(bool fShutdown);

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

    void CloseDb(const fs::path& filename);

    void ReloadDbEnv();

    DbTxn* TxnBegin(int flags);

};

/** Get BerkeleyEnvironment given a directory path. */

std::shared_ptr<BerkeleyEnvironment> GetBerkeleyEnv(const fs::path& env_directory, bool use_shared_memory);

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, fs::path filename, const DatabaseOptions& options);

    ~BerkeleyDatabase() override;

    /** Open the database if it is not already opened. */

    void Open() override;

    /** Rewrite the entire database on disk, with the exception of key pszSkip if non-zero

     */

    bool Rewrite(const char* pszSkip=nullptr) override;

    /** Indicate that a new database user has begun 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);

    /** Return path to main database filename */

    std::string Filename() override { return fs::PathToString(env->Directory() / m_filename); }

    std::string Format() override { return "bdb"; }

    /**

     * 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;

    // Whether to byteswap

    bool m_byteswap;

    fs::path m_filename;

    int64_t m_max_log_mb;

    /** Make a BerkeleyBatch connected to this database */

    std::unique_ptr<DatabaseBatch> MakeBatch(bool flush_on_close = true) override;

};

class BerkeleyCursor : public DatabaseCursor

{

private:

    Dbc* m_cursor;

    std::vector<std::byte> m_key_prefix;

    bool m_first{true};

public:

    // Constructor for cursor for records matching the prefix

    // To match all records, an empty prefix may be provided.

    explicit BerkeleyCursor(BerkeleyDatabase& database, const BerkeleyBatch& batch, std::span<const std::byte> prefix = {});

    ~BerkeleyCursor() override;

    Status Next(DataStream& key, DataStream& value) override;

    Dbc* dbc() const { return m_cursor; }

};

/** RAII class that provides access to a Berkeley database */

class BerkeleyBatch : public DatabaseBatch

{

private:

    bool ReadKey(DataStream&& key, DataStream& value) override;

    bool WriteKey(DataStream&& key, DataStream&& value, bool overwrite = true) override;

    bool EraseKey(DataStream&& key) override;

    bool HasKey(DataStream&& key) override;

    bool ErasePrefix(std::span<const std::byte> prefix) override;

protected:

    Db* pdb{nullptr};

    std::string strFile;

    DbTxn* activeTxn{nullptr};

    bool fReadOnly;

    bool fFlushOnClose;

    BerkeleyEnvironment *env;

    BerkeleyDatabase& m_database;

public:

    explicit BerkeleyBatch(BerkeleyDatabase& database, const bool fReadOnly, bool fFlushOnCloseIn=true);

    ~BerkeleyBatch() override;

    BerkeleyBatch(const BerkeleyBatch&) = delete;

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

    void Flush() override;

    void Close() override;

    std::unique_ptr<DatabaseCursor> GetNewCursor() override;

    std::unique_ptr<DatabaseCursor> GetNewPrefixCursor(std::span<const std::byte> prefix) override;

    bool TxnBegin() override;

    bool TxnCommit() override;

    bool TxnAbort() override;

    bool HasActiveTxn() override { return activeTxn != nullptr; }

    DbTxn* txn() const { return activeTxn; }

};

std::string BerkeleyDatabaseVersion();

/** Perform sanity check of runtime BDB version versus linked BDB version.

 */

bool BerkeleyDatabaseSanityCheck();

//! 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);

} // namespace wallet

#endif // BITCOIN_WALLET_BDB_H