void Main_DoInit()
{
// unprotect our entire PE image
HMODULE hModule;
if (SUCCEEDED(GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS, (LPCSTR)Main_DoInit, &hModule)))
{
Main_UnprotectModule(hModule);
}
InitBridge();
// return to the original EP
memcpy(originalEP, &originalCode, sizeof(originalCode));
__asm jmp originalEP
}
void Main_DoInit()
{
// unprotect our entire PE image
HMODULE hModule;
if (SUCCEEDED(GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS, (LPCSTR)Main_DoInit, &hModule)))
{
Main_UnprotectModule(hModule);
}
if (GetProcAddress(GetModuleHandle("kernel32.dll"), "InitializeSRWLock"))
{
LoadLibrary("gdimm_32.dll");
}
Sys_Init();
// return to the original EP
memcpy(originalEP, &originalCode, sizeof(originalCode));
__asm jmp originalEP
}
void Main_SetSafeInit()
{
// find the entry point for the executable process, set page access, and replace the EP
HMODULE hModule = GetModuleHandle(NULL); // passing NULL should be safe even with the loader lock being held (according to ReactOS ldr.c)
if (hModule)
{
PIMAGE_DOS_HEADER header = (PIMAGE_DOS_HEADER)hModule;
PIMAGE_NT_HEADERS ntHeader = (PIMAGE_NT_HEADERS)((DWORD)hModule + header->e_lfanew);
Main_UnprotectModule(hModule);
// back up original code
PBYTE ep = (PBYTE)((DWORD)hModule + ntHeader->OptionalHeader.AddressOfEntryPoint);
memcpy(originalCode, ep, sizeof(originalCode));
// patch to call our EP
int newEP = (int)Main_DoInit - ((int)ep + 5);
ep[0] = 0xE9; // for some reason this doesn't work properly when run under the debugger
memcpy(&ep[1], &newEP, 4);
originalEP = ep;
}
}
