Finit v4.0

[troglobit]

This release became v4.0, and not v3.2, because of incompatible changes to service conditions. There are other significant changes as well, so make sure to read the whole change log when upgrading.

Changes

• The stand-alone reboot tool has been replaced with a symlink to initctl, like its siblings: halt, shutdown, poweroff, and suspend. Calling reboot & C:o now defaults to the corresponding initctl cmd with a fallback to sending signals as per traditional SysV init. The -f (force) flag remains, where reboot(2) is called directly
• Introducing Finit progress 𝓜𝓸𝓭𝓮𝓻𝓷
• The inictl cond set|clear COND have changed completely. Constrained to a flat <usr/...> namespace and automatically activated by a new usr.so plugin that checks services for usr condition changes
• Removed built-in inetd super server. If you need this functionality, use an external inetd, like xinetd, instead. A pull request for a stand-alone inetd, like watchdogd and getty, is most welcome!
• Incompatible configure script changes, i.e., no guessing --prefix and other paths. Also, many options have been changed, renamed, or flipped defaults, or even dropped altogether. There are examples in the documentation and the contrib/ section
• Service conditions change from the non-obvious <svc/path/to/foo> to <pid/foo:id>. Not only does this give simpler internal semantics, it hopefully also makes it clear that one service's pid:!foo pidfile is another service's <pid/foo> condition, issue Redesign condition subsystem #143
• Initial support for cgroups v2:
  • services runs in a cgroup named after their respective *.conf file
  • top-level groups are; init, user, and system
  • all top-level groups can be configured from finit *.conf files
  • each service can tweak the cgroup settings
  • Use initctl [top|ps|cgroup] commands to inspect runtime state
  • https://twitter.com/b0rk/status/1214341831049252870?s=20
• Major refactor of Finit's main() function to be able to start the event loop earlier. This also facilitated factoring out functionality previously hard-coded in Finit, e.g., starting the bundled watchdogd, various distro packed udevd and other hotplugging tools
• A proper rescue mode has been added. It is started extremely early and is protected with a bundled suslogin. Exiting rescue mode now brings up the system as a normal boot, as one expects
• Support for sysv start/stop scripts as well as monitoring forking services, stared using sysv or service stanza
• Support for custom kill:DELAY, default 3 sec.
• Support for custom halt:SIGNAL, default SIGTERM
• Support for pre:script and post:script, allows for setup and teardown/cleanup before and after a service runs, issue Add support for exit callback/cleanup script #129
• Support for env:file in /etc/default/foo or /etc/conf.d/foo, see the contrib section for examples that utilize this feature. Variables expanded from env files, and the env files themselves, are tracked for changes to see if a service .conf file is "dirty" and needs restart on initctl reload
• Support for tracking custom PID files, using pid:!/path/to/foo.pid, useful with new sysv or service which fork to background
• Support starting run/task/services without absolute path, trust $PATH
• Add support for --disable-doc and --disable-contrib to speed up builds and work around issue with massively parallel builds
• Support for @console also for external getty
• Support for notty option to built-in getty, for board bring-up
• Support for rescue option to built-in getty, for rescue shells
• Add -b, batch mode, for non-interactive use to initctl
• Prefer udev to handle /dev/ if mdev is also available
• Redirect dbus daemon output to syslog
• Set $SHELL, like $PATH, to a sane default value, needed by BusyBox
• Finit no longer automatically reloads its *.conf files after running /etc/rc.local or run-parts. Use initctl reload instead.
• initctl without an argument or option now defaults to list services
• Convert built-in watchdog daemon to standalone mini watchdogd, issue Refactor start of built-in watchdogd as a regular service #102
• Improved watchdog hand-over, now based on svc_t and not PID
• Extended bootstrap, runlevel S, timeout: 10 --> 120 sec. before services not allowed in the runtime runlevel are unconditionally stopped
• Removed HOOK_SVC_START and HOOK_SVC_LOST, caused more problems than they were worth. Users are encouraged to use accounting instead
• Skip displaying "Restarting ..." progress for bootstrap processes
• Added a simple work queue mechanism to queue up work at boot + runtime
  • Postpone deletion of svc_t until any SIGKILL timer has elapsed
  • As long as a stepped service changes state we queue another step all event, because services may depend on each other
• Require new libuEv API: uev_init1() to reduce event cache so that the kernel can invalidate deleted events before enqueing to userspace
• Rename hwclock.so plugin to rtc.so since it now is stand-alone from the hwclock tool. Note: the kernel can also be set to load and store RTC to/from system clock at boot/halt as well, issue hwclock[TIME plugins] failed to execute #110
• New plugin to support cold plugging devices, auto-loading of modules at boot. Detects required modules by reading /sys/devices/*
• New plugin for /etc/modules-load.d/ by Robert Andersson, Atlas Copco
• New name:foo support for services, by Robert Andersson, Atlas Copco
• New manual:yes support for services, by Robert Andersson, Atlas Copco
• New log:console support for services, by Robert Andersson, Atlas Copco
• Support for :ID as a string, by Jonas Johansson, Westermo
• Support for auto-reload, instead of having to do initctl reload, when a service configuration has changed. Disabled by default, but can be enabled with ./configure --enable-auto-reload
• Support for logging security related events, e.g., runlevel change, start/stop or failure to start services, by Jonas Holmberg, Westermo
• Mount devtpts with recommended ptxmode=0666
• Mount /run tmpfs with nosuid,nodev,noexec for added security
• Support for console as alias for @console in tty stanzas
• Drop --enable-rw-roots configure option, use rw for your / partition in /etc/fstab instead to trigger remount at boot
• Drop default tty speed (38400) and use 0 (kernel default) instead
• Make :ID optional, use NULL/zero internally this allows ...
• Handle use-cases where multiple services share the same PID file and thus the same condition path, e.g. different instances for different runlevels. Allow custom condition path with name:foo syntax, creates conditions w/o a path, and ...
• Always append :ID qualifier to conditions if set for a service
• The IPC socket has moved from /run/finit.sock to /run/finit/socket officially only supported for use by the initctl tool
• The IPC socket now uses SOCK_SEQPACKET instead of SOCK_STREAM.
  Recommend using watchdogd v3.4, or later, which support this
• Improved support for modern /etc/network/interfaces, which has include statements. No more native ifup of individual interfaces,
  Finit now calls ifup -a, or ifdown -a, delegating all details to the operating system. Also, this is now done in the background, by popular request

Fixes

• Fix Wait for the temporary udev before finit exited it #96: Start udevd as a proper service
• Ensure we track run commands as well as task/service, once per runlevel
• Ensure run/tasks also go to stopping state on exit, like services, otherwise it is unnecessarily hard to restart them
• Fix missing OS/Finit title bug, adds leading newline before banner
• Remove "Failed connecting to watchdog ..." error message on systems that do not have a watchdog
• Fix finit errors on boot & trouble with logging #100: Early condition handling may not work if /var/run does not yet exist (symlink to /run). Added compat layer for access
• Fix Factor out built-in inetd into a separate process #101: Built-in inetd removed
• Fix Refactor start of built-in watchdogd as a regular service #102: Start built-in watchdogd as a regular service
• Fix @console not functional with multiple active consoles #103: Register multiple getty if @console resolves to >1 TTY,
• Fix /etc/nologin removed by finit when moving between normal runlevels #105: Only remove /etc/nologin when moving from runlevel 0, 1, 6. Fixed by Jonas Johansson, Westermo
• Fix Support for PID files created in sub-directories to /run #109: Support for PID files in sub-directories to /var/run
• Handle rename of PID files, by Robert Andersson, Atlas Copco
• Fix hwclock[TIME plugins] failed to execute #110: automatic modprobe of RTC devices, built-in hwclock
• Fix Redirect stdin to /dev/null by default #120: Redirect stdin to /dev/null for services by default
• Fix Switch to using nanosleep in favour of sleep #122: Switch to nanosleep() to achieve "signal safe" sleep. Fixed by Jacques de Laval, Westermo
• Fix Subprocesses not killed when run/task/service dies #124: Lingering processes in process group when session leader exits. E.g., lingering logit processes when parent dies
• Fix Always show all scripts executed from rc.local or runparts #127: Show all runparts scripts as they start, like rc.local. Fixed by Jacques de Laval, Westermo
• Fix service name matching, e.g. for condition handling, may match with wrong service. Fixed by Jonas Holmberg, Westermo
• Run all run-parts scripts using /bin/sh -c foo just like the standard run-parts tool. Found by Magnus Malm, Westermo
• Fix initctl [start | restart], should behave the same for services that have crashed. Found by Mattias Walström, Westermo
• Wait for bootstrap phase to complete before cleaning out any bootstrap processes that have stopped, they may be restarted again
• Reassert condition when an unmodified run/task/service goes from WAITING back to RUNNING again after a reconfiguration event. Found and fixed by Jonas Johansson, Westermo
• Restore Ctrl-D and Ctrl-U support in built-in getty
• Remove service condition when service is deleted
• Fix C++ compilation issues, by Robert Andersson, Atlas Copco
• Build fixes for uClibc
• Provide service description for built-in watchdog daemon
• Fix [RFC] Boot refactor #138: Handle SIGPWR like SIGSUR2, i.e., power off the system
• Drop the '%m' GNUism, for compat with older musl libc
• Fix System timezone changes does not "take" in Finit #139: call tzset() on initctl reload to activate system timezone changes (for logging)

---

This discussion was created from the release Finit v4.0.

[winkmichael]

Thanks for all of your hard work, can't wait to try this out this week!

[beeaniebee]

I wanted to ask: can finit run scripts in parallel? I know my Gentoo/OpenRC installation can be configured to boot the system with parallel processes, making the boot process significantly faster, but I wanted to know if finit has the same functionality or only runs scripts in sequence?

[troglobit]

It's a Fast Init (Finit), so yes that's what it does by default since its inception :)

[beeaniebee]

That's awesome! I'm definitely wanting to give this a try now!

[troglobit]

I don't have any examples in the contrib/ section for Gentoo, unfortunately. Hope you can manage anyway.

[troglobit]

Ping @yangfl :-)

[troglobit]

Demo of Finit v4 booting Alpine Linux 3.13 ✨

[pwFoo]

Nice!
Would take a look into finit for my custom minimal linux...

[psakar]

How does finit compare to dinit - https://davmac.org/projects/dinit/alpine-demo/ ?

[troglobit]

I don't really know. This is the first I've heard of dinit, which if I may say so, makes some bold claims ... Finit is 10+ years old, even predates systemd, so I rarely go out of my way these days to research alternatives. Sorry :)

Finit has dependency handling, even though it's not as elaborate as dinit (if B depends on A, we don't start A when we start B). Finit also takes a proactive stance towards memory allocation errors. After all, the main focus for the maintainer is in deeply embedded systems, so memory leaks or other bad memory handling have been a priority from day one.

If someone wants to do a comparative study, I can help out and answer questions, but I don't have the time do one myself.

[psakar]

@troglobit Thank you for your answer and nice project. It was not intent to ask you to spend much time, I was just wandering if you are aware of other project and hoping you can provide some pointers with respect how is the project different from your one.
For newbie as me both look very similar and is hard to say which one to choose :-)