wt/finit

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Joachim Wiberg c584795202 doc: fix back-references and stale claims left by the conversion

Reference sections kept pointing at the line-based format they no longer
document.  `sysv` and `task` sent the reader to Services for "<COND>",
the cgroups chapter opened by listing three legacy directives and then
explained further down that only two of them exist here, and the logging
chapter still gave "log:prio:facility.level,tag:ident" as the full
syntax.

Some claims were wrong independent of the format:

  - a sysv is a supervised daemon, grouped with service in
    SVC_TYPE_DAEMON, not a variation on task
  - restart-max has no upper bound of 255, or any other
  - the built-in rescue fallback runs in 12345789, not 12345
  - conditional loading quotes system/10-hotplug.conf, not
    system/hotplug.conf
  - the key spells conflicts, not conflict
  - the built-in getty no longer wants TERM last, it is a key

`if` takes either a service name or, in angle brackets, a condition,
decided in svc_ifthen().  Only the examples showed this, so it is now
said.

Terminology follows the split index.md already draws: a block is the new
format, a stanza the line-based one.

src/rescue.conf was still line-based, missed because it sits in src/
rather than system/ or contrib/.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

2026-07-30 15:23:35 +02:00

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Rescue Mode

Finit supports a rescue mode which is activated by the rescue option on the kernel command line. See cmdline docs for how to activate it.

This rescue mode can be disabled at configure time using:

configure --without-rescue

The rescue mode comes in two flavors; traditional and fallback.

Note

In this mode initctl will not work. Use the -f flag to force reboot, shutdown, or poweroff.

Traditional

This is what most users expect. A very early maintenance login prompt, served by the system sulogin program from util-linux, or BusyBox. If that is not found in $PATH, the bundled /libexec/finit/sulogin program is used instead. If a successful login is made, or if the user exits (Ctrl-D), the rescue mode is ended and the system boots up normally.

Warning

The bundled sulogin in Finit can at configure time be given another user than the default (root). If the sulogin user does not have a password, or the account is locked, the user is presented with a prompt: "Press enter to enter maintenance mode.", which will open up a root shell without prompting for password!

Fallback

If no sulogin program is found, Finit tries to bring up as much of its own functionality as possible, yet limiting many aspects, meaning; no network, no fsck of file systems in /etc/fstab, no /etc/rc.local, no runparts, and most plugins are skipped (except those that provide functionality for the condition subsystem).

Instead of reading /etc/finit.conf et al, system configuration is read from /lib/finit/rescue.conf, which can be freely modified by the system administrator.

The bundled default rescue.conf contains nothing more than:

runlevel = 1
tty rescue {
    runlevel = "12345"
    rescue   = true
}

The tty block has rescue set, which works similar to the board bring-up setting notty. The major difference being that sulogin is started to query for root/admin password. If sulogin is not found, rescue behaves like notty and gives a plain root shell prompt.

If Finit cannot find /lib/finit/rescue.conf it falls back to a built-in equivalent, which runs in every runlevel it can:

tty rescue {
    runlevel = "12345789"
    rescue   = true
}

There is no way to exit the fallback rescue mode.

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Rescue Mode

Traditional

Fallback

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