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 subshell. 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 subshell. If the script has a ‘.sh' suffix then it is sourced directly into the current shell.

Contents of 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 dhclient.

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).

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. /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.

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.

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.