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RC(8) System Manager's Manual RC(8)
NAME
rc, rc.local, rc.shutdown, rc.d/ - startup and shutdown scripts
SYNOPSIS
rc
rc.local
rc.shutdown
rc.d/
DESCRIPTION
rc is the command script which controls the startup of various services,
and is invoked by init(8) as part of the process of entering the
automatic reboot to multi-user startup, or after the single user mode
shell has exited. If init(8) is starting the automatic reboot process,
rc is invoked with the argument of `autoboot'.
rc.local is a command script to which local boot-time actions can be
added. It is (nearly) the last thing invoked by rc during a normal boot.
rc.shutdown is the command script which shuts down various services, and
is invoked by shutdown(8) as part of the process of shutting down the
system.
rc.d/ is the directory which contains various sh(1) scripts, one for each
service, which are called by rc at startup, rc.shutdown at shutdown, and
as necessary during system operation to stop, start, restart, reload, or
otherwise control the service.
Operation of rc
1. Source /etc/rc.subr to load various rc.subr(8) shell functions to
use.
2. If autobooting, set autoboot=yes and enable a flag (rc_fast=yes),
which prevents the rc.d scripts from performing the check for
already running processes (thus speeding up the boot process). This
rc_fast=yes speedup won't occur when rc is started up after exiting
the single-user shell.
3. Invoke rcorder(8) to order the files in /etc/rc.d/ that do not have
a "nostart" keyword (refer to rcorder(8)'s -s flag), and assigns the
result to a variable.
4. Calls each script in turn using run_rc_script() (from rc.subr(8)),
which sets $1 to `start', and sources the script in a sub-shell. If
the script has a `.sh' suffix then it is sourced directly into the
current shell.
5. The output from the above steps is sent to a post-processor. If
rc_silent is false, then the post-processor displays the output. If
rc_silent is true, then the post-processor invokes the command
specified in rc_silent_cmd once for each line, without otherwise
displaying the output. Useful values for rc_silent_cmd include ":"
to display nothing at all, and "twiddle" to display a spinning
symbol on the console. Regardless of the value of rc_silent, the
post-processor saves the output in /var/run/rc.log.
Operation of rc.shutdown
1. Source /etc/rc.subr to load various rc.subr(8) shell functions to
use.
2. Invoke rcorder(8) to order the files in /etc/rc.d/ that have a
"shutdown" keyword (refer to rcorder(8)'s -k flag), reverses that
order, and assigns the result to a variable.
3. Calls each script in turn using run_rc_script() (from rc.subr(8)),
which sets $1 to `stop', and sources the script in a sub-shell. If
the script has a `.sh' suffix then it is sourced directly into the
current shell.
Contents of rc.d/
rc.d/ is located in /etc/rc.d. The following file naming conventions are
currently used in rc.d/:
ALLUPPERCASE Scripts that are `placeholders' to ensure that
certain operations are performed before others. In
order of startup, these are:
NETWORKING Ensure basic network services are
running, including general network
configuration (network) and dhcpcd.
SERVERS Ensure basic services (such as
NETWORKING, ppp, syslogd, and kdc)
exist for services that start early
(such as named), because they're
required by DAEMON below.
DAEMON Before all general purpose daemons
such as dhcpd, lpd, and ntpd.
LOGIN Before user login services (inetd,
telnetd, rshd, sshd, and xdm), as
well as before services which might
run commands as users (cron, postfix,
and sendmail).
inline.sh Scripts that are sourced into the current shell
rather than a sub-shell have a `.sh' suffix.
Extreme care must be taken in using this, as the
startup sequence will terminate if the script
causes the current shell process to terminate.
/etc/rc.d/bootconf.sh uses this behaviour to allow
the user to select a different configuration
(including /etc/rc.conf) early in the boot.
service Scripts that are sourced in a sub-shell. The boot
does not stop if such a script terminates with a
non-zero status, but a script can stop the boot if
necessary by invoking the stop_boot() function
(from rc.subr(8)).
Each script should contain rcorder(8) keywords, especially an appropriate
"PROVIDE" entry.
The scripts are expected to support at least the following arguments:
start Start the service. This should check that the service is
to be started as specified by rc.conf(5). Also checks if
the service is already running and refuses to start if it
is. This latter check is not performed by standard NetBSD
scripts if the system is starting directly to multi-user
mode, to speed up the boot process.
stop If the service is to be started as specified by
rc.conf(5), stop the service. This should check that the
service is running and complain if it's not.
restart Perform a stop then a start.
status If the script starts a process (rather than performing a
one-off operation), show the status of the process.
Otherwise it's not necessary to support this argument.
Defaults to displaying the process ID of the program (if
running).
poll If the script starts a process (rather than performing a
one-off operation), wait for the command to exit.
Otherwise it's not necessary to support this argument.
rcvar Display which rc.conf(5) variables are used to control the
startup of the service (if any).
Other arguments (such as `reload', `dumpdb', etc) can be added if
necessary.
The argument may have one of the following prefixes to alter its
operation:
fast Skip the check for an existing running process. Sets
rc_fast=yes.
force Skips the rc.conf(5) check, ignores a failure result from
any of the prerequisite checks, executes the command, and
always returns a zero exit status. Sets rc_force=yes.
one Skips the rc.conf(5) check, but performs all other
prerequisite tests.
In order to simplify scripts, the run_rc_command() function from
rc.subr(8) may be used.
FILES
/etc/rc Startup script called by init(8).
/etc/rc.d/ Directory containing control scripts for each service.
/etc/rc.local Local startup script.
/etc/rc.shutdown Shutdown script called by shutdown(8).
/etc/rc.subr Contains rc.subr(8) functions used by various scripts.
/etc/rc.conf System startup configuration file.
/var/run/rc.log Log file created by rc.
SEE ALSO
rc.conf(5), init(8), rc.subr(8), rcorder(8), reboot(8), shutdown(8)
Luke Mewburn, "The Design and Implementation of the NetBSD rc.d system",
Proceedings of the FREENIX Track: 2001 USENIX Annual Technical
Conference, USENIX Association,
http://www.usenix.org/publications/library/proceedings/usenix01/freenix01/full_papers/mewburn/mewburn.pdf,
June 25-30, 2001.
HISTORY
The rc command appeared in 4.0BSD. The /etc/rc.d support was implemented
in NetBSD 1.5 by Luke Mewburn <lukem@NetBSD.org>. The post-processor,
support for rc_silent, and saving output to a file, was implemented in
NetBSD 6.0 by Alan Barrett.
NetBSD 10.99 October 15, 2017 NetBSD 10.99