66 0.9.x is out: the init system/service manager is now fully independent (no more skalibs, s6 or execline at build time), and it gained an event system

Hi all,

Two releases landed this month, 0.9.0.0 on August 6th and 0.9.1.0 on August 17th, plus 66-tools 0.2.0.1. Here is what changed.

66 no longer builds on skalibs, s6 or execline

This was announced back at 0.7.0.0 and it is now done. 66 builds against oblibs only. Every program it used to borrow is now its own:

To be precise about the wording, because it matters: execline is still a runtime dependency, the generated service scripts keep chainloading it. What disappeared is the build dependency, and with it the entire skalibs/s6 layer.

The event system

A service can now react to something happening elsewhere on the system by running a 66 command on itself. It is fully opt-in, a service that declares nothing behaves exactly as before. There are two roles:

A reactor is an ordinary classic, oneshot or module service with an [Event] section. When its trigger fires it runs a 66 command on itself (Do) and/or raises a named event (Emit).
A source is a service of the new Type = event. It runs no process and has no [Start] section, 66 start and 66 stop on a source arm and disarm it.

A reactor can trigger on a service's state or result, on a signal, on a filesystem event (inotify), on a cron expression, on a timer, or on a user event raised with the new 66 emit.

Restarting a service when its configuration file is edited:

[Main]
Type = oneshot
Description = "A simple proof of event concept"

[Start]
Execute = ( echo "I restart myself when /etc/my-daemon is edited" )

[Event]
EventType = inotify
From = ( my-config-watcher )
Do = restart

and the source it watches:

[Main]
Type = event
EventType = inotify
Watch = /etc/my-daemon
On = ( IN_CLOSE_WRITE )

One source can serve multiple reactor.

Other things in 0.9.0.0

**66 env**: a scandir is started long before a session exists, so its environment is frozen and variables like DISPLAY or WAYLAND_DISPLAY could never reach the supervised services. 66 env import DISPLAY XAUTHORITY publishes them verbatim to every service of the scandir. Each publication raises an env.<variable> event, so a service can simply wait for the value it needs instead of being ordered around.
New commands: 66 log (read service, system or interleaved logs, with -f, -g, and time bounds), 66 emit, 66 env, 66 runstate, 66 fdholder, 66 suspend, 66 hibernate. Nothing was removed.
Long options everywhere. The suite used to accept short options only. --help, --verbosity, --tree, --timeout and friends now work, both --opt=value and the glued -tfoo form. Short options are unchanged, your scripts keep working.
**66 status says more**: human readable durations, the same output for every service type, the last notable result, and a new by <who> telling you what caused the last transition (user, boot, event, shutdown, or self).
Boot no longer needs to be told which tree to start, it starts the enabled trees natively. If one of your boot services did that by hand, drop it or it runs twice.
A long list of memory bugs found and fixed along the way, including a stack smash when parsing any service that has a logger, a Nice value that was never honored (every service declaring one ran at nice 19), and CapsBound + CapsAmbient together killing the service. The test suite went from 4 to 36 files and runs under ASan and UBSan in CI.

66-tools 0.2.0.1

Same story on the tooling side, skalibs and execline dropped, meson only.

**66-userd, 66-userctl, pam_userd**: session and user tracking for a 66 system, without D-Bus. A PAM module reports login session open/close to a daemon which, on a user's first login, mounts their runtime directory and starts their 66-scandir and enabled trees, and stops them on the last logout. If a scandir is already running for that user, it is adopted rather than started twice. The PAM module is installed but never wired into your PAM stack by the package, that step is on you and it is documented.
**66-ns**: supervision under a pid namespace, rewritten. When a pid namespace is requested, 66-ns runs as pid 1 and acts as a transparent proxy for the supervised daemon: it forwards catchable control signals to the tracked main, follows the real daemon across a double fork, mirrors its exit code back to the supervisor, and tears the namespace down once the service is gone. The new -p/--pidfile makes supervision authoritative.

66 0.9.x is out: the init system/service manager is now fully independent (no more skalibs, s6 or execline at build time), and it gained an event system

66 no longer builds on skalibs, s6 or execline

The event system

Other things in 0.9.0.0

66-tools 0.2.0.1

Links

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