FEX-Emu--FEX/Source/Common/FEXServerClient.h

// SPDX-License-Identifier: MIT
#pragma once

#include <FEXCore/Utils/LogManager.h>
#include <FEXCore/fextl/string.h>
#include <FEXHeaderUtils/Syscalls.h>

namespace FEXServerClient {
  enum class PacketType {
    // Request and Result
    TYPE_KILL,
    TYPE_GET_LOG_FD,
    TYPE_GET_ROOTFS_PATH,
    TYPE_GET_PID_FD,

    // Result only
    TYPE_SUCCESS,
    TYPE_ERROR,
  };

  union FEXServerRequestPacket {
    struct Header {
      PacketType Type;
    } Header;

    struct {
      struct Header Header;
    } BasicRequest;
  };

  union FEXServerResultPacket {
    struct Header {
      PacketType Type;
    } Header;

    struct {
      struct Header Header;
      int32_t PID;
    } PID;

    struct {
      struct Header Header;
      size_t Length;
      char Mount[0];
    } MountPath;
  };

  constexpr size_t MAXIMUM_REQUEST_PACKET_SIZE = sizeof(FEXServerRequestPacket);

  fextl::string GetServerLockFolder();
  fextl::string GetServerLockFile();
  fextl::string GetServerRootFSLockFile();
  fextl::string GetTempFolder();
  fextl::string GetServerMountFolder();
  fextl::string GetServerSocketName();
  int GetServerFD();

  bool SetupClient(char *InterpreterPath);

  /**
   * @brief Connect to and start a FEXServer instance if required
   *
   * @return socket FD for communicating with server
   */
  int ConnectToAndStartServer(char *InterpreterPath);

  enum class ConnectionOption {
    Default,
    NoPrintConnectionError,
  };
  /**
   * @brief Connect to a FEXServer instance if it exists
   *
   * @return socket FD for communicating with server
   */
  int ConnectToServer(ConnectionOption ConnectionOption = ConnectionOption::Default);

  /**
   * @name Packet request functions
   * @{ */
  /**
   * @brief Request the server to be killed
   *
   * @param ServerSocket - Socket to the server
   */
  void RequestServerKill(int ServerSocket);

  /**
   * @brief Request a FEXServer to give us a log FD to write in to
   *
   * @param ServerSocket - Socket to the server
   *
   * @return FD for logging in to
   */
  int RequestLogFD(int ServerSocket);

  fextl::string RequestRootFSPath(int ServerSocket);

  /**
   * @brief Request a FEXServer to give us a pidfd of the process
   *
   * @param ServerSocket - Socket to the server
   *
   * @return FD for pidfd
   */
  int RequestPIDFD(int ServerSocket);

  /**  @} */

  /**
   * @name FEX logging through FEXServer
   * @{ */
  namespace Logging {
    enum class PacketTypes : uint32_t {
      TYPE_MSG,
    };

    struct PacketHeader {
      uint64_t Timestamp{};
      PacketTypes PacketType{};
      int32_t PID{};
      int32_t TID{};
      uint32_t Pad{};
      char Data[0];
    };

    struct PacketMsg {
      PacketHeader Header{};
      size_t MessageLength;
      uint32_t Level{};
      uint32_t Pad{};
    };

    static_assert(sizeof(PacketHeader) == 24, "Wrong size");

    [[maybe_unused]]
    static PacketHeader FillHeader(Logging::PacketTypes Type) {
      struct timespec Time{};
      uint64_t Timestamp{};
      clock_gettime(CLOCK_MONOTONIC, &Time);
      Timestamp = Time.tv_sec * 1e9 + Time.tv_nsec;

      Logging::PacketHeader Msg {
        .Timestamp = Timestamp,
        .PacketType = Type,
        .PID = ::getpid(),
        .TID = FHU::Syscalls::gettid(),
      };

      return Msg;
    }
  }

  void MsgHandler(int FD, LogMan::DebugLevels Level, char const *Message);
  void AssertHandler(int FD, char const *Message);
  /**  @} */
}