Howto prevent cycles in engine invocation ?

[Fuchs, Andreas]

Following scenario:

I have an engine that implements e.g. RSA decryption.
That engine links against a library that links against libcrypto to perform RSA decryption.

Now if I have an application that sets the default library to be my engine, won't I end up in an infinite loop ?

Or the other way around:
- Is there a way to change the default engine from within my engine before calling out to the library ?
- Can the library itself select "software-only" as an engine ?

I guess I don't have a concrete problem in my specific case, since I have app_data attached to any key and
if my engine receives a key without app_data, it will just call SSLeay() functions.

But what if that was not the case ?

Thanks a lot for any help,
Andreas