SysV Init Compatibility

It is not possible to run unmodified SysV init systems with Finit. This was never the intention and is not the strength of Finit. However, it comes with a few SysV Init compatibility features to ease the transition from a serialized boot process.

SysV Init Scripts

Syntax: sysv [LVLS] <COND> /path/to/init-script -- Optional description

<COND> is described in the Services section.

Similar to task is the sysv stanza, which can be used to call SysV style scripts. The primary intention for this command is to be able to reuse much of existing setup and init scripts in Linux distributions.

When entering an allowed runlevel, Finit calls init-script start, when entering a disallowed runlevel, Finit calls init-script stop, and if the Finit .conf, where sysv stanza is declared, is modified, Finit calls init-script restart on initctl reload. Similar to how service stanzas work.

Forking services started with sysv scripts can be monitored by Finit by declaring the PID file to look for: pid:!/path/to/pidfile.pid. Notice the leading !, it signifies Finit should not try to create the file, but rather watch that file for the resulting forked-off PID. This syntax also works for forking daemons that do not have a command line option to run it in the foreground, more on this below in service.

Tip

See also SysV Init Compatibility.

runparts DIRECTORY

For a directory with traditional start/stop scripts that should run, in order, at bootstrap, Finit provides the runparts directive. It runs in runlevel S, at the very end of it (before calling /etc/rc.local) making it perfect for most scenarios.

For syntax details, see the Run-parts Scripts section. Here is an example take from a Debian installation:

runparts /etc/rc2.d

Files in these directories are usually named SNNfoo and KNNfoo, which Finit knows about and automatically appends the correct argument:

/bin/sh -c /etc/rc2.d/S01openbsd-inetd start

or

/bin/sh -c /etc/rc0.d/K01openbsd-inetd stop

Files that do not match this pattern are started similarly but without the extra command line argument.

Start/Stop Scripts

For syntax details, see SysV Init Scripts, above. Here follows an example taken from a Debian installation:

sysv [2345] <pid/syslogd> /etc/init.d/openbsd-inetd -- OpenBSD inet daemon

The init script header could be parsed to extract Default-Start: and other parameters for the sysv command to Finit. There is currently no way to detail a generic syslogd dependency in Finit, so Should-Start: in the header must be mapped to the condition system in Finit using an absolute reference, here we depend on the sysklogd project's syslogd.

/etc/rc.local

One often requested feature, early on, was a way to run a site specific script to set up, e.g., static routes or firewall rules. A user can add a task or run command in the Finit configuration for this, but for compatibility reasons the more widely know /etc/rc.local is used if it exists, and is executable. It is called very late in the boot process when the system has left runlevel S, stopped all old and started all new services in the target runlevel (default 2).

In Finit releases before v4.5 this script blocked Finit execution and made it as good as impossible to call initctl during that time.

init q

When /sbin/finit is installed as /sbin/init, it is possible to use init q to reload the configuration. This is the same as calling initctl reload.