RC(8)

NAME
rc - command scripts for auto-reboot and daemon startup

SYNOPSIS
rc
rc.conf
rc.conf.local
rc.d/
rc.local.d/
rc.firewall
rc.local
rc.shutdown
rc.shutdown.local
rc.subr

DESCRIPTION
The rc utility is the command script which controls the automatic boot process after being called by init(8). The rc.local and rc.shutdown.local scripts contains commands which are pertinent only to a specific site. Typically, scripts in /usr/local/etc/rc.d/ is used instead of rc.local and rc.shutdown.local these days but if you want to use them it is still supported. In this case, they should source /etc/rc.conf and contain additional custom startup and shutdown code for your system. The best way to handle rc.local and rc.shutdown.local, however, is to separate them 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. This directory is typically maintained by the system. rc.local.d/ directories contain scripts which will be automatically executed at boot time and shutdown time. This directory is typically maintained by the sysadmin.

  Operation of

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 will not occur when rc is started up after exiting the single-user shell.

3.  If the file /firstboot does not exist, add “firstboot” to the list of KEYWORDS to skip in rcorder(8).

4.  Invoke rcorder(8) to order the files in /etc/rc.d/ and /etc/rc.local.d/ that do not have a “nostart” keyword (refer to rcorder(8)'s -s flag), and assign the result to a variable.

5.  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.

6.  If the file /firstboot exists, delete it.

  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/ and /etc/rc.local.d/ that have a “shutdown” keyword (refer to rcorder(8)'s -k flag), reverse that order, and assign the result to a variable.

3.  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:

    FILESYSTEMS
        Ensure that root and other critical local file systems are mounted.

    NETWORKING
        Ensure basic network services are running, including general network configuration (netif, routing, network_ipv6, ppp).

    SERVERS
        Ensure basic services (such as syslogd) exist for services that start early (such as named), because they are required by DAEMON below.

    DAEMON
        Check-point before all general purpose daemons such as dntpd and lpd.

    LOGIN
        Check-point before user login services (inetd and sshd), as well as services which might run commands as users (cron, jail 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 terminates.

bar Scripts that are sourced in a subshell. These can stop the boot if necessary with the following shell commands:

        if [ "$autoboot" = yes ]; then
        	kill -TERM $$
        fi
        exit 1

    Note that this should be used extremely sparingly!

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 DragonFly scripts if the system is starting directly to multi-user mode, to speed up the boot process. If faststart is given, skip the PID check. 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.

reload
    Send $sig_reload (defaults to HUP) to the program(s) associated with the service. Note that not all scripts enable the reload command.

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).

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.

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 only argument. At shutdown time, it is passed the string “stop” as its 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).

SCRIPTS OF INTEREST
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 to “preen” all UFS(5) file systems of minor inconsistencies resulting from the last system shutdown. If preening fails further action depends on the rc.conf(5) variable fsck_y_enable: if the value is “NO” (default) rc exits, if value is “YES”, fsck(8) is run with option -y, if this also fails rc exits. 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/localdaemons script can execute scripts from multiple rc.d/ directories. The default locations are /usr/local/etc/rc.d/ and /usr/pkg/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 /etc/rc.d/{net*,routing} scripts are used to start the network. The network is started in several passes. The first pass, /etc/rc.d/netif, configures the network interfaces. The /etc/rc.d/routing script starts routing and sets routing options. The /etc/rc.d/netoptions script sets additional networking options. Finally, the /etc/rc.d/network_ipv6 script configures IPv6 interfaces and options.

The rc.firewall script is used to configure rules for the ipfw(4) 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 specifically check that they are on that architecture before starting the daemon.

Following tradition, all startup files reside in /etc.

FILES
/etc/rc
/etc/rc.conf
/etc/rc.conf.local
/etc/rc.d/
/etc/rc.firewall
/etc/rc.local
/etc/rc.shutdown
/etc/rc.shutdown.local
/etc/rc.subr

EXAMPLES
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
    # BEFORE:  baz_service_requiring_foo_to_precede_it
    . /etc/rc.subr
    name="foo"
    rcvar=`set_rcvar`
    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=`set_rcvar`
    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"

The following is a simple, hypothetical example of an old-style /usr/local/etc/rc.d/ script, which would start a daemon at boot time, and kill it at shutdown time.

    #!/bin/sh -
    #
    #    initialization/shutdown script for foobar package
    case "$1" in
    start)
    	/usr/local/sbin/foo -d && echo -n ' foo'
    	;;
    stop)
    	kill `cat /var/run/foo.pid` && echo -n ' foo'
    	;;
    *)
    	echo "unknown option: $1 - should be 'start' or 'stop'" >&2
    	;;
    esac

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

SEE ALSO
kill(1), ipfw(4), rc.conf(5), init(8), rcorder(8), rcrun(8), rc.subr(8), reboot(8), savecore(8)

HISTORY
The rc utility appeared in 4.0BSD. The rc.d/ facility was implemented in NetBSD 1.5 and appeared in DragonFly 1.0.