> -----Original Message----- > From: Lennart Poettering [mailto:lenn...@poettering.net] > Sent: Friday, December 30, 2011 11:13 > To: Michael D. Berger > Cc: systemd-devel@lists.freedesktop.org > Subject: Re: [systemd-devel] extra SIGTERM > > On Thu, 29.12.11 19:14, Michael D. Berger (m.d.ber...@ieee.org) wrote: > > > myDaemon.service: > > > > [Unit] > > Description=myDaemon > > After=syslog.target network.target > > > > [Service] > > PIDFile=/var/lock/subsys/myDaemon > > Type=simple > > ControlGroup=cpu:/ > > ExecStart=/usr/sbin/myDaemon --daemon > > #ExecStop=/bin/kill -s SIGTERM $MAINPID > > > > [Install] > > WantedBy=multi-user.target > > > > Using the service as shown, when I stop myDaemon, it gets > one SIGTERM > > . > > > > However, if I uncomment the ExecStop line, it gets two SIGTERMs in > > rapid succession. > > > > Looks like a bug to me. What do you think? > > How else should this behave? Note that sending SIGTERM with > kill() is asynchronous. So what happens is that your > /bin/kill invocation enqueues SIGTERM, and then systemd will > kill what is remaining after that, also with SIGTERM. Since > there's no wait in between that means that two SIGTERMs are > sent one right after the other (since the kernel might > coalesce identical signals, if they aren't processed quickly > you might still see them as a single signal in times.) > > What did you expect instead? > > Note that you can influence which signal is sent by systemd, > and to which processes: with KillMode= and KillSignal=. You > can also control whether a final SIGKILL shall be sent as > last fallback if the service doesn't react to SIGTERM within > a timeout. You can even turn off all sending of signals by > systemd, with SendSIGKILL=no and KillMode=none. > > Or in other word: explicitly invoking /bin/kill in ExecStop= > is almost always entirely redundant. > > So, as far as I can see everything behaves as it should? > > Lennart > > -- > Lennart Poettering - Red Hat, Inc. >
I had assumed that ExecStop would replace the automatic delivery of SIGTERM, so there would be only one SIGTERM. Your explanation is clear. Thanks, Mike. -- Michael D. Berger m.d.ber...@ieee.org http://www.rosemike.net/ _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
