I am doing some weird stuff. I duplicate functions and modify
them in a portable way. One problem I have is that I cannot get
data in a relative way to be able to access attached functional
data.
Here is an kinda of thought example,
void base(int a, int b, int c)
{
...
}
This function is duplicated byte wise using memcpy. Extra
information is added to the these bytes that I would like to
access in base, but no absolute addresses can be used and
portability must be maintained. One can imagine the data attached
to the start or end of the function.
Using assembly, it is relatively easy. Just get eip at start of
function, get the length of the function, then access the data
like mov eax, [eip+length]. This is not portable though.
The function signature cannot change either or, it too, would be
easy as I could just pass the offsets. I have no control over the
calling mechanism. I can only create a functional template then
copy that and attach data that it can use. I have seen some
methods to do this but they all are unsafe as they might create
undefined behavior in specific instances.
Do I have any options?
Thanks.
