bug#45202: pcscd service (pcsc-lite) doesn't handle run directory properly

[Raffael Stocker]

Tobias Geerinckx-Rice writes:

>> However, I now noticed a new one: pcscd doesn't seem to be killable
>> easily (at least not by a TERM signal), so "herd stop pcscd" has
>> no effect.  Sending a KILL signal and starting with "herd start pcscd"
>> works without problems, though.
>
> I can reproduce this.  Interestingly(?) it only affects the pcscd started by
> Shepherd.
>
> Manual $(guix build pcsc-lite)/sbin/pcscd invocations, both with and without
> --foreground, are eminently killable with TERM alone.

Interesting indeed.  From looking at the source of pcsc-lite (main() in
pcscdaemon.c) it seems it's not modifying its sigmask.  IIRC, child
processes inherit the parent's ignored signals, so if shepherd is
ignoring SIGTERM before a fork() and not resetting to default before an
exec(), pcscd will never receive the SIGTERM.  This might explain the
behaviour.  I have not checked shepherd's source to confirm.

If this is so, it should probably be fixed in shepherd, right?

Regards,
Raffael