[Pcsclite-muscle] How to find out which process is accessing the card?

[František Řezáč]

Hi,

I'm using smart card for almost everything in my daily work, but I have a
problem which drives me crazy. I'm using YubiKey in two scenarios: pkcs11
based PAM and SSH authentication and also as a GPG‎ smart card. I
understand that accesing one card via pkcs11 and scdaemon in turns is
troubling, because GPG tends to lock the access to the card for itself full
time, but I can handle that by manualy terminating scdaemon.

But I have also come across the opossite situation many times - something
locks access to the card via pkcs11 which prevents the access from scdaemon
with the dreaded "PC/SC OPEN failed: sharing violation". The problem is
that I don't know which process is using the card so I don't know how to
deal with it except for restarting the whole pcscd. Also this problem seems
to happen randomly so I don't have any clue if it's pam module or ssh agent
or something else and it also randomly disappears. If I know what is using
the card, I could try to configure it better or deal with it more gently.

And that's my question - how to find out what is currently
accessing/locking the card at a given time? I tried to figure it out
myself, but after I have seen this schema
https://blog.flameeyes.eu/2011/04/additional-notes-about-the-smartcard-components-diagram/
I realized that I don't even know at which level I should look for that
information.

--
František
http://calavera.info/
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