Ludovic Rousseau wrote on 06/04/2020: > Le 05/04/2020 à 16:40, Paride Legovini a écrit : >> Hello Ludovic, >> >> On Fri, 3 Apr 2020 15:37:20 +0200 Ludovic Rousseau >> <ludovic.rouss...@free.fr> wrote: > >>> When it fails: >>> - is the socket /var/run/pcscd/pcscd.comm still present? >> >> This was a hint in the right direction and I think it makes most of the >> logs I collected useless. Apparently when the problem occurs the >> /var/run/pcscd/pcscd.comm socket is not there anymore, but systemd still >> have a file descriptor open for it, as I found out using lsof: >> >> COMMAND PID TID TASKCMD USER FD TYPE DEVICE >> SIZE/OFF NODE NAME >> systemd 1 root 45u unix 0xffffa066a5154400 >> 0t0 3172053 /run/pcscd/pcscd.comm type=STREAM >> >> I think the systemd socket unit (pcscd.socket) does not recreate the >> socket because of this, and passes a "dead" file descriptor to pcscd. >> What exactly deletes the pcscd.comm socket is not clear to me. Now after >> fiddling with pcscd I don't think I have clean logs to provide, I prefer >> to wait for the problem to happen again and then check if anything >> relevant is logged. I did try to suspend/resume a few times but but I >> didn't manage to reproduce the issue. But maybe you know what could be >> deleting the socket. > > pcscd can remove the /var/run/pcscd/pcscd.comm socket but only when NOT > started by systemd. This is done on init and exit of pcscd. > When pcscd is started by systemd you have a log message like: > Apr 03 12:51:52 stramonio pcscd[98472]: 00000032 pcscdaemon.c:451:main() > Started by systemd > > Maybe, sometimes, pcscd does not detect it is started by systemd. But in > this case the socket should be re-created by pcscd so that should not be > the correct explanation. > > Or maybe the problem is on the systemd side? > > You can continue generating logs. They are a good indication of what is > happening. > You can limit logs to the info level using --info instead of --debug. > You can also remove the --apdu argument. > > If I read correctly your previous message you have logs with: > - pcscd is started by systemd > - pcscd correctly indicates "Started by systemd" > - but the communication is broken (pcsc_scan fails) and I guess the file > /var/run/pcscd/pcscd.comm is missing > - you stop pcscd: systemctl stop pcscd > - you start pcscd: systemctl start pcscd > - pcscd correctly indicates "Started by systemd" > - the communication is still broken and, I guess, the file > /var/run/pcscd/pcscd.comm is still missing
All correct, this fits what I observe and I think it is what is happening, but before digging more I want to collect some cleaner logs, just to be sure. While trying to debug this I tried different things, including starting pcscd manually (outside systemd), so my logs are dirty now, and I don't want to lose time on a red herring. > To re-create the file /var/run/pcscd/pcscd.comm you need to use: > systemctl stop pcscd.socket > systemctl start pcscd.socket Correct. > See also > https://ludovicrousseau.blogspot.com/2011/11/pcscd-auto-start-using-systemd.html > > > I still have no clue when and why the socket file is removed. Thanks, all useful information. I'll keep the service running with --info and try to understand what happens when the socket is lost. Paride
