statement_reader.h

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/*
  Copyright (c) 2018, 2024, Oracle and/or its affiliates.
 
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 2.0,
  as published by the Free Software Foundation.
 
  This program is designed to work with certain software (including
  but not limited to OpenSSL) that is licensed under separate terms,
  as designated in a particular file or component or in included license
  documentation.  The authors of MySQL hereby grant you an additional
  permission to link the program and your derivative works with the
  separately licensed software that they have either included with
  the program or referenced in the documentation.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
 
#ifndef MYSQLD_MOCK_STATEMENT_READER_INCLUDED
#define MYSQLD_MOCK_STATEMENT_READER_INCLUDED
 
#include <chrono>
#include <memory>
#include <optional>
#include <string>
#include <utility>
#include <variant>
#include <vector>
 
#include <openssl/bio.h>
 
#include "mysql/harness/net_ts/buffer.h"
#include "mysql/harness/net_ts/executor.h"
#include "mysql/harness/net_ts/io_context.h"
#include "mysql/harness/net_ts/timer.h"
#include "mysql/harness/tls_error.h"
#include "mysql/harness/tls_server_context.h"
#include "mysql_protocol_common.h"
#include "mysqlrouter/classic_protocol_constants.h"
 
#include "authentication.h"
#include "mysql/harness/net_ts/internet.h"
#include "mysql/harness/net_ts/socket.h"
#include "mysql/harness/stdx/expected.h"
#include "mysql/harness/stdx/monitor.h"
#include "mysqlrouter/classic_protocol_message.h"
#include "mysqlrouter/classic_protocol_session_track.h"
 
namespace server_mock {
 
/** @brief Vector for keeping has_value|string representation of the values
 *         of the single row (ordered by column)
 **/
using RowValueType = std::vector<std::optional<std::string>>;
 
using session_tracker_field =
    std::variant<classic_protocol::session_track::TransactionCharacteristics,
                 classic_protocol::session_track::TransactionState,
                 classic_protocol::session_track::SystemVariable,
                 classic_protocol::session_track::Schema,
                 classic_protocol::session_track::State,
                 classic_protocol::session_track::Gtid>;
 
std::string encode_session_trackers(
    const std::vector<session_tracker_field> &trackers);
 
/** @brief Keeps result data for single SQL statement that returns
 *         resultset.
 **/
struct ResultsetResponse {
  std::vector<classic_protocol::message::server::ColumnMeta> columns;
  std::vector<RowValueType> rows;
 
  classic_protocol::message::server::Eof end_of_rows;
};
 
using OkResponse = classic_protocol::message::server::Ok;
using ErrorResponse = classic_protocol::message::server::Error;
 
struct AsyncNotice {
  // how many milliseconds after the client connects this Notice
  // should be sent to the client
  std::chrono::milliseconds send_offset_ms;
  unsigned type;
  bool is_local;  // true = local, false = global
  std::string payload;
};
 
class ProtocolBase {
 public:
  using protocol_type = net::ip::tcp;
  using socket_type = typename protocol_type::socket;
  using endpoint_type = typename protocol_type::endpoint;
 
  ProtocolBase(socket_type client_sock, endpoint_type client_ep,
               TlsServerContext &tls_ctx);
 
  ProtocolBase(const ProtocolBase &) = delete;
  ProtocolBase(ProtocolBase &&) = delete;
 
  ProtocolBase &operator=(const ProtocolBase &) = delete;
  ProtocolBase &operator=(ProtocolBase &&rhs) = delete;
 
  virtual ~ProtocolBase() = default;
 
  // throws std::system_error
  virtual void encode_error(const ErrorResponse &resp) = 0;
 
  // throws std::system_error
  virtual void encode_ok(const OkResponse &resp) = 0;
 
  // throws std::system_error
  virtual void encode_resultset(const ResultsetResponse &response) = 0;
 
  stdx::expected<size_t, std::error_code> read_ssl(
      const net::mutable_buffer &buf);
 
  stdx::expected<size_t, std::error_code> write_ssl(
      const net::const_buffer &buf);
 
  stdx::expected<size_t, std::error_code> avail_ssl();
 
  template <class CompletionToken>
  void async_send_tls(CompletionToken &&token) {
    net::async_completion<CompletionToken, void(std::error_code, size_t)> init{
        token};
 
    const auto write_res = write_ssl(net::buffer(send_buffer_));
    if (!write_res) {
      auto write_ec = write_res.error();
 
      if (write_ec == TlsErrc::kWantRead || write_ec == TlsErrc::kWantWrite) {
        client_socket_.async_wait(
            write_ec == TlsErrc::kWantRead ? net::socket_base::wait_read
                                           : net::socket_base::wait_write,
            [this, compl_handler = std::move(init.completion_handler)](
                std::error_code ec) mutable {
              if (ec) {
                compl_handler(ec, {});
                return;
              }
 
              async_send(std::move(compl_handler));
            });
      } else {
        net::defer(client_socket_.get_executor(),
                   [compl_handler = std::move(init.completion_handler),
                    ec = write_res.error()]() { compl_handler(ec, {}); });
      }
    } else {
      net::dynamic_buffer(send_buffer_).consume(write_res.value());
 
      net::defer(client_socket_.get_executor(),
                 [compl_handler = std::move(init.completion_handler),
                  transferred = write_res.value()]() {
                   compl_handler({}, transferred);
                 });
    }
 
    return init.result.get();
  }
 
  template <class CompletionToken>
  void async_send(CompletionToken &&token) {
    if (is_tls()) {
      async_send_tls(std::forward<CompletionToken>(token));
    } else {
      net::async_write(client_socket_, net::dynamic_buffer(send_buffer_),
                       std::forward<CompletionToken>(token));
    }
  }
 
  // TlsErrc to net::stream_errc if needed.
  static std::error_code map_tls_error_code(std::error_code ec) {
    return (ec == TlsErrc::kZeroReturn) ? net::stream_errc::eof : ec;
  }
 
  template <class CompletionToken>
  void async_receive_tls(CompletionToken &&token) {
    net::async_completion<CompletionToken, void(std::error_code, size_t)> init{
        token};
 
    auto buf = net::dynamic_buffer(recv_buffer_);
 
    auto orig_size = buf.size();
    auto grow_size = 16 * 1024;
 
    buf.grow(grow_size);
    size_t transferred{};
    auto read_res = read_ssl(buf.data(orig_size, grow_size));
    if (read_res) {
      transferred = read_res.value();
    }
 
    buf.shrink(grow_size - transferred);
 
    if (!read_res) {
      const auto read_ec = read_res.error();
      if (read_ec == TlsErrc::kWantRead || read_ec == TlsErrc::kWantWrite) {
        client_socket_.async_wait(
            read_ec == TlsErrc::kWantRead ? net::socket_base::wait_read
                                          : net::socket_base::wait_write,
            [this, compl_handler = std::move(init.completion_handler)](
                std::error_code ec) mutable {
              if (ec) {
                compl_handler(ec, {});
                return;
              }
 
              async_receive_tls(std::move(compl_handler));
            });
      } else {
        // as we can't handle the error, forward the error to the
        // completion handler
 
        net::defer(
            client_socket_.get_executor(),
            [compl_handler = std::move(init.completion_handler),
             ec = map_tls_error_code(read_ec)]() { compl_handler(ec, {}); });
      }
    } else {
      // success, forward it to the completion handler
      net::defer(client_socket_.get_executor(),
                 [compl_handler = std::move(init.completion_handler),
                  transferred]() { compl_handler({}, transferred); });
    }
 
    return init.result.get();
  }
 
  template <class CompletionToken>
  void async_receive(CompletionToken &&token) {
    is_terminated_([&](const bool killed) {
      if (killed) {
        net::async_completion<CompletionToken, void(std::error_code, size_t)>
            init{token};
 
        net::defer(client_socket_.get_executor(),
                   [compl_handler = std::move(init.completion_handler)]() {
                     compl_handler(
                         make_error_code(std::errc::operation_canceled), 0);
                   });
      } else if (is_tls()) {
        return async_receive_tls(std::forward<CompletionToken>(token));
      } else {
        return net::async_read(client_socket_,
                               net::dynamic_buffer(recv_buffer_),
                               std::forward<CompletionToken>(token));
      }
    });
  }
 
  template <class CompletionToken>
  void async_tls_accept(CompletionToken &&token) {
    net::async_completion<CompletionToken, void(std::error_code)> init{token};
 
    // data may already be pending
    auto res = tls_accept();
    if (!res) {
      auto ec = res.error();
      if (ec == TlsErrc::kWantRead || ec == TlsErrc::kWantWrite) {
        auto wt = ec == TlsErrc::kWantRead ? net::socket_base::wait_read
                                           : net::socket_base::wait_write;
 
        client_socket_.async_wait(
            wt, [&, compl_handler = std::move(init.completion_handler)](
                    std::error_code ec) mutable {
              if (ec) {
                compl_handler(ec);
                return;
              }
 
              // call async accept again.
              async_tls_accept(std::move(compl_handler));
            });
      } else {
        net::defer(client_socket_.get_executor().context(),
                   [ec, compl_handler = std::move(init.completion_handler)]() {
                     compl_handler(ec);
                   });
      }
    } else {
      net::defer(client_socket_.get_executor().context(),
                 [compl_handler = std::move(init.completion_handler)]() {
                   compl_handler({});
                 });
    }
 
    return init.result.get();
  }
 
  const std::vector<uint8_t> &send_buffer() const { return send_buffer_; }
 
  const net::ip::tcp::socket &client_socket() const { return client_socket_; }
 
  void username(const std::string &username) { username_ = username; }
 
  std::string username() const { return username_; }
 
  void auth_method_name(const std::string &auth_method_name) {
    auth_method_name_ = auth_method_name;
  }
 
  std::string auth_method_name() const { return auth_method_name_; }
 
  void auth_method_data(const std::string &auth_method_data) {
    auth_method_data_ = auth_method_data;
  }
 
  std::string auth_method_data() const { return auth_method_data_; }
 
  static bool authenticate(const std::string &auth_method_name,
                           const std::string &auth_method_data,
                           const std::string &password,
                           const std::vector<uint8_t> &auth_response);
 
  void init_tls();
 
  bool is_tls() { return bool(ssl_); }
 
  const SSL *ssl() const { return ssl_.get(); }
 
  stdx::expected<void, std::error_code> tls_accept();
 
  net::steady_timer &exec_timer() { return exec_timer_; }
 
  void cancel();
 
  /**
   * terminate the current connection.
   *
   * sets is_terminated(true) and cancels the current operation.
   *
   * may be called from another thread.
   */
  void terminate();
 
  net::io_context &io_context() {
    return client_socket_.get_executor().context();
  }
 
 private:
  Monitor<bool> is_terminated_{false};
 
 protected:
  socket_type client_socket_;
  endpoint_type client_ep_;
  net::steady_timer exec_timer_{io_context()};
 
  std::string username_{};
  std::string auth_method_name_{};
  std::string auth_method_data_{};
 
  TlsServerContext &tls_ctx_;
 
  class SSL_Deleter {
   public:
    void operator()(SSL *v) { SSL_free(v); }
  };
 
  std::unique_ptr<SSL, SSL_Deleter> ssl_;
 
  std::vector<uint8_t> recv_buffer_;
  std::vector<uint8_t> send_buffer_;
};
 
class StatementReaderBase {
 public:
  struct handshake_data {
    classic_protocol::message::server::Greeting greeting;
 
    std::optional<std::string> username;
    std::optional<std::string> password;
    bool cert_required{false};
    std::optional<std::string> cert_subject;
    std::optional<std::string> cert_issuer;
 
    std::chrono::microseconds exec_time;
  };
 
  StatementReaderBase() = default;
 
  StatementReaderBase(const StatementReaderBase &) = default;
  StatementReaderBase(StatementReaderBase &&) = default;
 
  StatementReaderBase &operator=(const StatementReaderBase &) = default;
  StatementReaderBase &operator=(StatementReaderBase &&) = default;
 
  virtual ~StatementReaderBase() = default;
 
  /** @brief Returns the data about the next statement from the
   *         json file. If there is no more statements it returns
   *         empty statement.
   **/
  virtual void handle_statement(const std::string &statement,
                                ProtocolBase *protocol) = 0;
 
  /** @brief Returns the default execution time in microseconds. If
   *         no default execution time is provided in json file, then
   *         0 microseconds is returned.
   **/
  virtual std::chrono::microseconds get_default_exec_time() = 0;
 
  virtual std::vector<AsyncNotice> get_async_notices() = 0;
 
  virtual stdx::expected<handshake_data, ErrorResponse> handshake(
      bool is_greeting) = 0;
 
  virtual void set_session_ssl_info(const SSL *ssl) = 0;
};
 
}  // namespace server_mock
 
#endif