[Pcsclite-muscle] Delegate WinSCard calls to another library (for a RDP server for example)

[Ludovic Rousseau]

Hello,

I am working on a new idea for pcsc-lite: Delegate WinSCard calls to
another library

The application will call SCardEstablishContext() (for example) as
before but the call is not directly sent to libpcsclite.so.1. Instead
we have a intermediate library that can redirect the call somewhere
else.

Use cases:
- the other library can be libpcscspy.0.dylib to generate a debug
trace (simpler use for
https://blog.apdu.fr/posts/2022/06/pcsc-api-spy-update/)
- the other library can be libpcsclite-xrdp.so.0 to redirect the PC/SC
calls to the RDP server and then to the RDP client
- something else. I am interested in reading your other ideas

The redirection is done by defining the environment variable
LIBPCSCLITE_DELEGATE before running the PC/SC application.

To avoid security problems the variable LIBPCSCLITE_DELEGATE is
ignored if the process is run as root. The default library (real
libpcsclite) is used instead.

You can have more details and a discussion in
https://github.com/LudovicRousseau/PCSC/issues/161

What do you think?
Should I change something?
Ideas? comments?

Thanks

-- 
 Dr. Ludovic Rousseau