/***************************************************Project Mutator****************************************************/
//-*-c++-*-
/*first line intentionally left blank.*/
/*loads the objects into executable memory and registers them with lua.*/
/*Copyright (C) 2017 Farzad Sadeghi

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

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 Street, Fifth Floor, Boston, MA  02110-1301, USA.*/
/**********************************************************************************************************************/
#include <iostream>
#include <tuple>
#include <vector>
#include <cstdint>
#include <cstdarg>
#include <cstring>
#include <sys/mman.h>
#include <unistd.h>
#include "lua-5.3.4/src/lua.hpp"
/**********************************************************************************************************************/
#ifndef EXECUTIONER_H
#define EXECUTIONER_H
/**********************************************************************************************************************/
namespace { // start of anonymous namespace
  using XObject = void(*)(void);
  constexpr int MEMORY_SIZE = 32768;
  std::vector<uint8_t> memory(MEMORY_SIZE, 0);

  void* alloc_writeable_memory(size_t _size) {
    void* ptr = mmap(0, _size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
    if (ptr == (void*)-1) {
      perror("could not allocate virtual memory.");
      return nullptr;
    }
    return ptr;
  }

  int make_mem_executable(void* _mem, size_t _size) {
    if (mprotect(_mem, _size, PROT_READ | PROT_EXEC) == -1) {
      perror("could not make virtual memory executable.");
      return -1;
    }
    return 0;
  }

  std::vector<uint8_t> arg_emitter(std::vector<uint8_t> _args) {}

  int LuaXobjWrapper(lua_State* __ls) {
    int numargs = lua_gettop(__ls);
    std::vector<uint8_t> arg_vec;
    std::string xfuncname;
    std::vector<std::pair<intptr_t, int>> arg_ptr;
    std::vector<std::pair<std::string, int>> arg_str;
    std::vector<std::pair<double, int>> arg_double;
    std::vector<std::pair<bool, int>> arg_bool;

    if (lua_type(__ls, 1) == LUA_TSTRING) {
      xfuncname = lua_tostring(__ls, 1);
    } else {
      //PRINT_WITH_COLOR_LB(RED, "the first argument should be a string that is the name of the xfunc to be called.");
    }
    
    // detecting arg types
    for (int i = 2; i <= numargs; ++i) {
      if (lua_type(__ls, i) == LUA_TBOOLEAN) {
        arg_bool.push_back(std::make_pair(!!lua_tonumber(__ls, i), i));
      }
      else if (lua_type(__ls, i) == LUA_TLIGHTUSERDATA) {
      }
      else if (lua_type(__ls, i) == LUA_TNUMBER) {
      }
      else if (lua_type(__ls, i) == LUA_TSTRING) {
      }
      else if (lua_type(__ls, i) == LUA_TTABLE) {
      }
      else if (lua_type(__ls, i) == LUA_TFUNCTION) {
      }
      else if (lua_type(__ls, i) == LUA_TUSERDATA) {
      }
      else if (lua_type(__ls, i) == LUA_TTHREAD) {
      }
      // type is Nil
      else {
      }
    }

    pid_t pid = fork();
    if (pid < 0) {
      //PRINT_WITH_COLOR_LB(RED, "could not fork...");
      lua_pushnumber(__ls, EXIT_FAILURE);
    }
    if (pid == 0) {}
    if (pid > 0) {
    }

    return 0;
  }
} // end of anonymous namespace

int getMemorySize(void) {return MEMORY_SIZE;}

class Executioner {
  public:
    Executioner() {}
    ~Executioner() {
      for (auto &iter : obj_mem_ptrs) {
        if (iter.first != nullptr) {
          if (munmap(iter.first, iter.second) < 0) {
            perror("could not unmap vmemory.");
          }
        }
      }
    }

    void getObjs(std::vector<std::vector<uint8_t>>& _objs) {objs = _objs;}

    void getNames(std::vector<std::string>& _names) {names = _names;}

    std::pair<void*, size_t> loadObjsInXMem(std::vector<uint8_t>& _obj_code) {
      size_t code_size = _obj_code.size();
      void* program_memory = alloc_writeable_memory(code_size);
      if (program_memory == nullptr) {
        std::cout << "could not allocate virtual memory\n";
        return std::make_pair(nullptr, 0);
      }
      memcpy(program_memory, _obj_code.data(), code_size);
      if (make_mem_executable(program_memory, code_size) < 0) {
        std::cout << "could not make vmemory executable.\n";
        return std::make_pair(nullptr, 0);
      }
      return std::make_pair(program_memory, code_size);
    }

    void loadAll(void) {
      for (auto &iter : objs) {
        this->loadObjsInXMem(iter);
      }
    }

    void emitByte(uint8_t _byte, std::vector<uint8_t>& _code) {
      _code.push_back(_byte);
    }

    void emitBytes(std::vector<uint8_t>& _bytes, std::vector<uint8_t>& _code) {
      for (auto &iter : _bytes) {this->emitByte(iter, _code);}
    }

    void registerWithLua(lua_State* _lua_State) {
      lua_register(_lua_State, "xobjwrapper", LuaXobjWrapper);
    }

    void xobjsGetPtrs(void) {
      for (auto& iter : obj_mem_ptrs) {
        XObject dummy = (XObject)iter.first;
        xobjs.push_back(dummy);
      }
    }

  private:
    std::vector<std::pair<void*, size_t>> obj_mem_ptrs;
    std::vector<std::vector<uint8_t>> objs;
    std::vector<std::string> names;
    std::vector<XObject> xobjs;
};
/**********************************************************************************************************************/
#endif
/**********************************************************************************************************************/
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