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RC(8) System Manager's Manual RC(8)

rc — command scripts for auto-reboot and daemon startup

rc

rc.conf

rc.conf.local

rc.d/

rc.firewall

rc.local

rc.shutdown

rc.subr

The rc utility is the command script which controls the automatic boot process after being called by init(8). The rc.local script contains commands which are pertinent only to a specific site. Typically, the /usr/local/etc/rc.d/ mechanism is used instead of rc.local these days but if you want to use rc.local, it is still supported. In this case, it should source /etc/rc.conf and contain additional custom startup code for your system. The best way to handle rc.local, however, is to separate it out into rc.d/ style scripts and place them under /usr/local/etc/rc.d/. The rc.conf file contains the global system configuration information referenced by the startup scripts, while rc.conf.local contains the local system configuration. See rc.conf(5) for more information.

The rc.d/ directories contain scripts which will be automatically executed at boot time and shutdown time.

The sysrc(8) command provides a scripting interface to modify system config files.

  1. 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 will not occur when rc is started up after exiting the single-user shell.
  2. Determine whether the system is booting diskless, and if so run the /etc/rc.initdiskless script.
  3. Source /etc/rc.subr to load various rc.subr(8) shell functions to use.
  4. Load the configuration files.
  5. Determine if booting in a jail, and add “nojail” (no jails allowed) or “nojailvnet” (only allow vnet-enabled jails) to the list of KEYWORDS to skip in rcorder(8).
  6. If the file ${firstboot_sentinel} does not exist, add “firstboot” to the list of KEYWORDS to skip in rcorder(8).
  7. 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).
  8. Call each script in turn using () (from rc.subr(8)), which sets $1 to “start”, and sources the script in a subshell. If the script has a .sh suffix then it is sourced directly into the current shell. Stop processing when the script that is the value of the $early_late_divider has been run.
  9. Check again to see if the file ${firstboot_sentinel} exists (in case it is located on a newly mounted file system) and adjust the list of KEYWORDs to skip appropriately.
  10. Re-run rcorder(8), this time including the scripts in the $local_startup directories. Ignore everything up to the $early_late_divider, then start executing the scripts as described above.
  11. If the file ${firstboot_sentinel} exists, delete it. If the file ${firstboot_sentinel}-reboot also exists (because it was created by a script), then delete it and reboot.

  1. Source /etc/rc.subr to load various rc.subr(8) shell functions to use.
  2. Load the configuration files.
  3. Invoke rcorder(8) to order the files in /etc/rc.d/ and the $local_startup directories that have a “shutdown” KEYWORD (refer to rcorder(8)'s -k flag), reverse that order, and assign the result to a variable.
  4. Call each script in turn using run_rc_script() (from rc.subr(8)), which sets $1 to “stop”, and sources the script in a subshell. If the script has a .sh suffix then it is sourced directly into the current shell.

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.
SERVERS
Ensure basic services exist for services that start early (such as nisdomain), because they are required by DAEMON below.
DAEMON
Check-point before all general purpose daemons such as lpd and ntpd.
LOGIN
Check-point before user login services (inetd and sshd), as well as services which might run commands as users (cron and sendmail).
foo.sh
Scripts that are to be sourced into the current shell rather than a subshell have a .sh suffix. Extreme care must be taken in using this, as the startup sequence will terminate if the script does.
bar
Scripts that are sourced in a subshell. 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 () function (from rc.subr(8)).

Each script should contain rcorder(8) keywords, especially an appropriate “PROVIDE” entry, and if necessary “REQUIRE” and “BEFORE” keywords.

Each script is expected to support at least the following arguments, which are automatically supported if it uses the () function:

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 FreeBSD scripts if the system is starting directly to multi-user mode, to speed up the boot process. If forcestart is given, ignore the rc.conf(5) check and start anyway.
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 is not. If forcestop is given, ignore the rc.conf(5) check and attempt to stop.
Perform a stop then a start.
If the script starts a process (rather than performing a one-off operation), show the status of the process. Otherwise it is not necessary to support this argument. Defaults to displaying the process ID of the program (if running).
Enable the service in rc.conf(5).
Disable the service in rc.conf(5).
Remove the service from rc.conf(5). If ‘service_delete_empty’ is set to “YES”, /etc/rc.conf.d/$servicename will be deleted if empty after modification.
Print a short description of what the script does.
Print the script's non-standard commands.
If the script starts a process (rather than performing a one-off operation), wait for the command to exit. Otherwise it is not necessary to support this argument.
Return 0 if the service is enabled and 1 if it is not. This command does not print anything.
Display which rc.conf(5) variables are used to control the startup of the service (if any).

If a script must implement additional commands it can list them in the extra_commands variable, and define their actions in a variable constructed from the command name (see the EXAMPLES section).

The following key points apply to old-style scripts in /usr/local/etc/rc.d/:

When an automatic reboot is in progress, rc is invoked with the argument autoboot. One of the scripts run from /etc/rc.d/ is /etc/rc.d/fsck. This script runs fsck(8) with option -p and -F to “preen” all the disks of minor inconsistencies resulting from the last system shutdown. If this fails, then checks/repairs of serious inconsistencies caused by hardware or software failure will be performed in the background at the end of the booting process. If autoboot is not set, when going from single-user to multi-user mode for example, the script does not do anything.

The /etc/rc.d/local script can execute scripts from multiple rc.d/ directories. The default location includes /usr/local/etc/rc.d/, but these may be overridden with the local_startup rc.conf(5) variable.

The /etc/rc.d/serial script is used to set any special configurations for serial devices.

The rc.firewall script is used to configure rules for the kernel based firewall service. It has several possible options:

will allow anyone in
will try to protect just this machine
will try to protect a whole network
totally disables IP services except via lo0 interface
disables the loading of firewall rules
filename
will load the rules in the given filename (full path required).

Most daemons, including network related daemons, have their own script in /etc/rc.d/, which can be used to start, stop, and check the status of the service.

Any architecture specific scripts, such as /etc/rc.d/apm for example, specifically check that they are on that architecture before starting the daemon.

Following tradition, all startup files reside in /etc.

/etc/rc
 
/etc/rc.conf
 
/etc/rc.conf.local
 
/etc/rc.d/
 
/etc/rc.firewall
 
/etc/rc.local
 
/etc/rc.shutdown
 
/etc/rc.subr
 
/var/run/dmesg.boot
dmesg(8) results soon after the rc process begins. Useful when dmesg(8) buffer in the kernel no longer has this information.

The following is a minimal rc.d/ style script. Most scripts require little more than the following.

#!/bin/sh
#

# PROVIDE: foo
# REQUIRE: bar_service_required_to_precede_foo

. /etc/rc.subr

name="foo"
rcvar=foo_enable
command="/usr/local/bin/foo"

load_rc_config $name
run_rc_command "$1"

Certain scripts may want to provide enhanced functionality. The user may access this functionality through additional commands. The script may list and define as many commands at it needs.

#!/bin/sh
#

# PROVIDE: foo
# REQUIRE: bar_service_required_to_precede_foo
# BEFORE:  baz_service_requiring_foo_to_precede_it

. /etc/rc.subr

name="foo"
rcvar=foo_enable
command="/usr/local/bin/foo"
extra_commands="nop hello"
hello_cmd="echo Hello World."
nop_cmd="do_nop"

do_nop()
{
	echo "I do nothing."
}

load_rc_config $name
run_rc_command "$1"

As all processes are killed by init(8) at shutdown, the explicit kill(1) is unnecessary, but is often included.

kill(1), rc.conf(5), init(8), rc.subr(8), rcorder(8), reboot(8), savecore(8), sysrc(8)

The rc utility appeared in 4.0BSD.

September 18, 2018 FreeBSD-12.0