[Pcsclite-muscle] SCardBeginTransaction behavior under sharing violation

[Maksim Ivanov]

Hello Ludovic,

Thank you for the fix!

And I'll try to find out internally whether there's some bug with my
email address :-)


Regards,
Maksim


On Mon, Oct 16, 2023 at 9:35 PM Ludovic Rousseau
<ludovic.rousseau at gmail.com> wrote:
>
> Le ven. 6 oct. 2023 à 21:11, Maksim Ivanov <emaxx at google.com> a écrit :
> > Hello,
>
> Hello Maksim,
>
> Sorry for the delay. Your email was in the gmail spam folder. Funny
> for a email from @google.com
>
> > SCardBeginTransaction() is documented as "there will be no action
> > taken" in case the reader is already locked. Also the
> > SCARD_E_SHARING_VIOLATION error code is documented to be returned in
> > case "someone else has exclusive rights".
>
> Exact
> Documentation at
> https://pcsclite.apdu.fr/api/group__API.html#gaddb835dce01a0da1d6ca02d33ee7d861
> is/was incorrect.
>
> > However, judging from the implementation, it seems that the
> > SCardBeginTransaction enters a poll loop, waiting for particular
> > results from the daemon. If I'm reading it correctly, the loop doesn't
> > exit as long as SCARD_E_SHARING_VIOLATION is received from the daemon
> > (https://github.com/LudovicRousseau/PCSC/blob/52670e567267baf3579581f32ef3756a3644b9f2/src/winscard_clnt.c#L1193),
> > meaning that the function would never return this code to the caller.
> >
> > If so, is this an oversight in the documentation, or rather in the
> > implementation?
>
> From SCardBeginTransaction MSDN
> https://learn.microsoft.com/en-us/windows/win32/api/winscard/nf-winscard-scardbegintransaction
> " The function waits for the completion of all other transactions
> before it begins. ".
> So blocking is the expected behaviour.
>
> I fixed the documentation in
> https://github.com/LudovicRousseau/PCSC/commit/14fae208e37b991efdcc858e34af3b8c57809ddb
>
> Thanks
>
> --
>  Dr. Ludovic Rousseau