RC0(1M) (Essential Utilities) RC0(1M)
NAME
rc0 - run commands performed to stop the operating system
SYNOPSIS
/etc/rc0
DESCRIPTION
This file is executed at each system state change that needs
to have the system in an inactive state. It is responsible
for those actions that bring the system to a quiescent
state, traditionally called ``shutdown''.
There are three system states that require this procedure.
They are state 0 (the system halt state), state 5 (the
system is secured for powerdown/reset), and state 6
(essentially the same as state 5). Whenever there is a
change to one of these states, the /etc/rc0 procedure is
run. The entry in /etc/inittab might read:
s0:056:wait:/etc/rc0 >/dev/console 2>&1 </dev/console
Some of the actions performed by /etc/rc0 are carried out by
files in the directory /etc/shutdown.d and files beginning
with K in /etc/rc0.d. These files are executed in ASCII
order (see FILES below for more information), terminating
some system service. The combination of commands in
/etc/rc0 and files in /etc/shutdown.d and /etc/rc0.d
determines how the system is shut down.
The recommended sequence for /etc/rc0 is:
Stop System Services and Daemons.
Various system services (such as LP Spooler) are
gracefully terminated.
When new services are added that should be terminated
when the system is shut down, the appropriate files are
installed in /etc/shutdown.d and /etc/rc0.d.
Page 1 May 1989
RC0(1M) (Essential Utilities) RC0(1M)
Terminate Processes
SIGTERM signals are sent to all running processes by
killall(1M). Processes stop themselves cleanly if sent
SIGTERM.
Kill Processes
SIGKILL signals are sent to all remaining processes; no
process can resist SIGKILL.
At this point, the only processes left are those
associated with /etc/rc0 and processes 0 and 1, which
are special to the operating system.
Unmount All File Systems
Only the root file system (/) remains mounted.
Depending on which system state the systems end up in (0, 5,
or 6), the entries in /etc/inittab will direct what happens
next. If the /etc/inittab has not defined any other actions
to be performed as in the case of system state 0, then the
operating system will have nothing to do.
FILES
The execution by /bin/sh of any files in /etc/shutdown.d
occurs in ASCII sort-sequence order. See rc2(1M) for more
information.
SEE ALSO
killall(1M), rc2(1M), shutdown(1M).
BUGS
Neither System V/68 nor System V/88 can be rebooted from
software. The reset switch must always be used.
Page 2 May 1989