11.5 Starting Services

11.5.1 Extended Application Configuration

Now that FreeBSD includes rc.d, configuration of application startup has become easier, and more featureful. Using the key words discussed in the rc.d section, applications may now be set to start after certain other services for example DNS; may permit extra flags to be passed through rc.conf in place of hard coded flags in the start up script, etc. A basic script may look similar to the following:

#!/bin/sh
#
# PROVIDE: utility
# REQUIRE: DAEMON
# KEYWORD: shutdown

. /etc/rc.subr

name="utility"
rcvar=`set_rcvar`
command="/usr/local/sbin/utility"

load_rc_config $name

#
# DO NOT CHANGE THESE DEFAULT VALUES HERE
# SET THEM IN THE /etc/rc.conf FILE
#
utility_enable=${utility_enable-"NO"}
utility_pidfile=${utility_pidfile-"/var/run/utility.pid"}

pidfile="${utility_pidfile}"

run_rc_command "$1"

This script will ensure that the provided utility will be started after the DAEMON pseudo-service. It also provides a method for setting and tracking the PID, or process ID file.

This application could then have the following line placed in /etc/rc.conf:

utility_enable="YES"

This method also allows for easier manipulation of the command line arguments, inclusion of the default functions provided in /etc/rc.subr, compatibility with the rcorder(8) utility and provides for easier configuration via the rc.conf file.

11.5.2 Using Services to Start Services

Other services, such as POP3 server daemons, IMAP, etc. could be started using inetd(8). This involves installing the service utility from the Ports Collection with a configuration line added to the /etc/inetd.conf file, or by uncommenting one of the current configuration lines. Working with inetd and its configuration is described in depth in the inetd section.

In some cases it may make more sense to use the cron(8) daemon to start system services. This approach has a number of advantages because cron runs these processes as the crontab's file owner. This allows regular users to start and maintain some applications.

The cron utility provides a unique feature, @reboot, which may be used in place of the time specification. This will cause the job to be run when cron(8) is started, normally during system initialization.