public static RedirectCallsState RevertJumpTo(IntPtr site, RedirectCallsState state)
{
RedirectCallsState detourState;
unsafe
{
byte* sitePtr = (byte*)site.ToPointer();
detourState = GetState(sitePtr);
*sitePtr = state.a; // mov r11, target
*(sitePtr + 1) = state.b;
*((ulong*)(sitePtr + 2)) = state.f;
*(sitePtr + 10) = state.c; // jmp r11
*(sitePtr + 11) = state.d;
*(sitePtr + 12) = state.e;
}
return detourState;
}
public static void Deploy()
{
if (_deployed)
{
return;
}
if (_originalPtr == IntPtr.Zero)
{
_originalPtr = typeof(BuildingManager).GetMethod("CalculateOutsideConnectionCount", BindingFlags.Instance | BindingFlags.Public).MethodHandle.GetFunctionPointer();
}
if (_detourPtr == IntPtr.Zero)
{
_detourPtr = typeof(BuildingManagerDetour).GetMethod("CalculateOutsideConnectionCount", BindingFlags.Instance | BindingFlags.Public).MethodHandle.GetFunctionPointer();
}
_state = RedirectionHelper.PatchJumpTo(_originalPtr, _detourPtr);
_deployed = true;
}
private static unsafe RedirectCallsState GetState(byte* sitePtr)
{
var state = new RedirectCallsState
{
a = *sitePtr,
b = *(sitePtr + 1),
c = *(sitePtr + 10),
d = *(sitePtr + 11),
e = *(sitePtr + 12),
f = *((ulong*) (sitePtr + 2))
};
return state;
}
public static void RevertRedirect(MethodInfo from, RedirectCallsState state)
{
var fptr1 = from.MethodHandle.GetFunctionPointer();
RevertJumpTo(fptr1, state);
}