Systemd 254 released

Posted Jul 28, 2023 21:55 UTC (Fri) by gdamjan (subscriber, #33634)
In reply to: Systemd 254 released by flussence
Parent article: Systemd 254 released

The service manager gained support for enqueuing POSIX signals to services that carry an additional integer value, exposing the sigqueue() system call. This is accessible via new D-Bus calls org.freedesktop.systemd1.Manager.QueueSignalUnit() and org.freedesktop.systemd1.Unit.QueueSignal(), as well as in systemctl via the new --kill-value= option.

I don't see that available in daemontools?!

Systemd 254 released

Posted Jul 30, 2023 2:58 UTC (Sun) by mirabilos (subscriber, #84359) [Link] (5 responses)

RTFM. svc -{pchaitk} sends signals to dæmons.

Yeah, this is ridiculous.

Systemd 254 released

Posted Jul 30, 2023 9:16 UTC (Sun) by derobert (subscriber, #89569) [Link] (4 responses)

Sending SIGTERM/QUIT/KILL/etc. like those flags is something that systemd has had forever.

This is something different (though related). It let's you additionally send an integer or pointer along with the signal. See the sigqueue manpage (the syscall the changelog mention): https://man7.org/linux/man-pages/man3/sigqueue.3.html

Systemd 254 released

Posted Jul 30, 2023 12:45 UTC (Sun) by lindi (subscriber, #53135) [Link] (3 responses)

Interesting, didn't know something like that existed. Any idea how it is typically used?

Systemd 254 released

Posted Jul 30, 2023 13:13 UTC (Sun) by bluca (subscriber, #118303) [Link]

systemd daemons support that as an alternative to IPC calls, currently it can be used to change log level or log target, trim memory, or dump malloc_info to journal

Systemd 254 released

Posted Jul 30, 2023 19:43 UTC (Sun) by mirabilos (subscriber, #84359) [Link] (1 responses)

Mostly 「svc -t /service/$foo」 to restart it.

Systemd 254 released

Posted Jul 30, 2023 22:43 UTC (Sun) by intelfx (subscriber, #130118) [Link]

That's not what the GP asked about, though.

Nobody doubts that svc can send signals, what's being discussed is the ability to send an accompanying item of data _together_ with the signal number.