rc
—
command scripts for auto-reboot and daemon
startup
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.
Operation of
rc
- 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.
- Determine whether the system is booting diskless, and if so run the
/etc/rc.initdiskless script.
- Source /etc/rc.subr to load various
rc.subr(8)
shell functions to use.
- Load the configuration files.
- 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).
- If the file ${firstboot_sentinel} does
not exist, add “
firstboot
” to the
list of KEYWORDS to skip in
rcorder(8).
- 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).
- Call each script in turn using
run_rc_script
() (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.
- 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.
- 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.
- 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.
Operation of
rc.shutdown
- Source /etc/rc.subr to load various
rc.subr(8)
shell functions to use.
- Load the configuration files.
- 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.
- 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.
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.
- 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
stop_boot
() 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
run_rc_command
() function:
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
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.
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 is not. If
forcestop
is
given, ignore the
rc.conf(5)
check and attempt to stop.
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 is not necessary
to support this argument. Defaults to displaying the process ID of the
program (if running).
enable
- Enable the service in
rc.conf(5).
disable
- Disable the service in
rc.conf(5).
delete
- 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.
describe
- Print a short description of what the script does.
extracommands
- Print the script's non-standard commands.
poll
- 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.
enabled
- Return 0 if the service is enabled and 1 if it is not. This command does
not print anything.
rcvar
- 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/:
- Scripts are only executed if their
basename(1)
matches the shell globbing pattern
*.sh, and they are executable. Any
other files or directories present within the directory are silently
ignored.
- When a script is executed at boot time, it is passed the string
“
start
” as its first and only
argument. At shutdown time, it is passed the string
“stop
” as its first and only
argument. All rc.d/
scripts are
expected to handle these arguments appropriately. If no action needs to be
taken at a given time (either boot time or shutdown time), the script
should exit successfully and without producing an error message.
- The scripts within each directory are executed in lexicographical order.
If a specific order is required, numbers may be used as a prefix to the
existing filenames, so for example
100.foo would be executed before
200.bar; without the numeric prefixes
the opposite would be true.
- The output from each script is traditionally a space character, followed
by the name of the software package being started or shut down,
without a trailing newline character (see the
EXAMPLES section).
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:
open
- will allow anyone in
client
- will try to protect just this machine
simple
- will try to protect a whole network
closed
- totally disables IP services except via
lo0 interface
UNKNOWN
- 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.