[fprint] libfprint suggestions

[Diego Zuccato]

Daniel Drake ha scritto:

> There are 2 storage mechanisms. The simple one saves it in the home 
> directory, the more advanced one gives you a binary blob that you can 
> save wherever you want.
Very good. I said I'm a newbie at libfprint, so it seems I missed 
something in the API.

> pam_fprint uses the simple mechanism, but pam_fprint really is a very 
> quick proof of concept that I wrote in about 15 minutes (most of the 
> time spent learning about PAM). It has numerous issues and doesn't work 
> with many apps (because those apps expect password input and break with 
> anything else), but is OK as a quick proof of concept.
Well, IMVHO it quite correctly follows the KISS paradigm. I don't think 
it's really a good thing make it dependent on too many components...
I'm using it w/ GDM and xlock w/o problems. The only bad thing is that 
they ask a password anyway (but it can be empty). And the messages 
appear in popup windows (have to click OK or press Enter). Console login 
works perfectly: no password is asked unless fingerprint fails.

> The "real" solution we're working towards is creating a D-Bus daemon 
> (fprintd) with pluggable storage backends, and then integrating apps 
> directly with that D-Bus API (bypassing PAM).
That can be perfect for non-system auth (for example to unlock GPG 
private key or replace Thunderbird's master password), but I wouldn't 
recommend it for a PAM module to let users login.

>> 3) add fp_print_to_string or public array finger_names to avoid 
>> replicating in every client. Could be interesting i18n support
> I avoided it this far in order to keep clear of i18n stuff.
Good reason. :-)

> The library should support being initialized twice and should have a 
> concept of sessions/contexts so that one context does not interfere with 
> another even when libfprint is being used twice in the same app. 
> libusb-1.0 implements this. 
Very good. My experience w/ libusb is quite limited and refers to a 0.x 
version.

> (libfprint has many other rough edges too, we have work to be done)
Is there something a newbie like me could have a look at to help?

BYtE,
  Diego.