[Pcsclite-muscle] Rare race condition in SCardGetStatusChange()

[Maximilian Stein]

On 17.04.2018 16:42, Ludovic Rousseau wrote:
> 
> In CMD_WAIT_READER_STATE_CHANGE case you add:
> +#ifdef USE_USB
> +                /* wait until all readers are ready */
> +                RFWaitForReaderInit();
> +#endif
> 
> Why?

Because I use CMD_WAIT_READER_STATE_CHANGE to dump the reader states to
the client (done inside EHRegisterClientForEvent()). So I mindlessly
copied this behaviour from CMD_GET_READERS_STATE, which was used
originally by SCardGetStatusChange().

But thinking about it, there is still a chance that a new reader is
discovered and not fully initialized exactly while dumping the reader
states. If this is not a problem, the call to RFWaitForReaderInit()
could be removed from both CMD_GET_READERS_STATE and
CMD_WAIT_READER_STATE_CHANGE. Otherwise updating and dumping the reader
states should maybe be synchronized by a mutex to avoid invalid state
information.

Regards,
Maximilian