How to signal smart card activity at the PC/SC level? Using D-Bus? HAL?

[Ludovic Rousseau]

2009/9/1 Bastien Nocera <hadess at hadess.net>:
> On Thu, 2009-08-27 at 14:51 +0200, Ludovic Rousseau wrote:
>> Hello,
>>
>> I am the maintainer of pcsc-lite [1] a middleware to access smart
>> cards and smart cards readers.
>> I am really new to D-Bus and HAL.
>>
>> Someone asked for an applet that would indicate if a card activity is
>> ongoing or not. The idea is to have the equivalent of a smart card
>> reader blinking LED but in a gnome applet. The idea is nice. Some of
>> my readers do not blink the LED when an APDU is exchanged so it is not
>> easy to know if something is happening. In general I look at the pcscd
>> debug logs but a Gnome applet would be nicer/more integrated.
>>
>> My question is: what mechanism to use to convey the information?
>> I was thinking of using D-Bus and also provide other information like
>> reader insertion/removal, card insertion/removal. And then card
>> communication status.
>>
>> I need a one-way only event mechanism to signal events. Maybe D-Bus is
>> too complex and HAL is the correct answer to my problem?
>>
>> Is D-Bus a good enough mechanism for that? Or should I use something
>> else? Is HAL more appropriate?
>> Any comment on this idea?
>>
>> This may be related to the smart_card_reader HAL name space proposed
>> (and accepted) in [2].
>
> It would be great if pcsc-lite could behave more like other daemons that
> handle hardware:
> - D-Bus interface for enumeration of devices, and device properties

The idea is that a D-Bus application could get information from
pcsc-lite? Or the other way around, pcscd using D-Bus to get hardware
information?

> - startup through udev (a-la bluetoothd), or when an application calls
> one of its function (if usable even without hardware plugged in, as in
> fprintd [1])

This feature is on the TODO list.
http://svn.debian.org/wsvn/pcsclite/trunk/PCSC/TODO

Thanks

-- 
 Dr. Ludovic Rousseau