Contents

  1. The rc.d System
    1. Basics
    2. The rc.d scripts
    3. Order/dependencies of start determined by rcorder
    4. rc.d scripts of additional services
    5. Additional Reading

The rc.d System

NetBSD uses individual scripts for controlling system and service startup, similar to System V, but without runlevels. Nowadays, most Linux distributions switched to systemd, which is a different approach: It does not use scripts anymore, but tries to have everything binary. It also serves for several other purposes, while NetBSD's rc.d system just serves for starting up services at system startup or by user intervention.

This chapter is an overview of NetBSD's rc.d system and its configuration.

Basics

The system startup files reside in the /etc directory. They are:

First, a look at controlling and supporting scripts (also documented in rc(8)):

There are some special scripts outside the rc.d directory, which are also run:

rc.d scripts are controlled by a central configuration file, /etc/rc.conf, which loads its default settings from /etc/defaults/rc.conf. If you want to change a default setting, do not edit /etc/defaults/rc.conf; instead, override the setting in /etc/rc.conf.

It is a good idea to read the rc.conf(5) man page to learn about the services that are by default available to you.

The following example shows how to enable the SSH daemon, which is disabled by default:

# cd /etc; grep ssh defaults/rc.conf
sshd=NO                 sshd_flags=""
# echo "sshd=YES" >> rc.conf

Now sshd(8) will be started automatically at system startup. The next section describes how to start and stop services at any time.

Last but not least, files can be created in the /etc/rc.conf.d/ directory to override the behavior of a given rc.d script without editing the script itself.

The rc.d scripts

The actual scripts that control services are in /etc/rc.d. These scripts are automatically run at boot time, but they can be called manually if necessary. The following example shows how to start the SSH daemon that we enabled in the previous section:

# /etc/rc.d/sshd start
Starting sshd.

Later, if you wish to stop the SSH daemon, run the following command:

# /etc/rc.d/sshd stop
Stopping sshd.
Waiting for PIDS: 123.

The rc.d scripts take one of the following arguments:

Some scripts may support other arguments (e.g., reload), but every script will support at least the above commands.

As an example, after adding a new record to a named(8) database, the daemon can be told to reload its configuration files with the following command:

# /etc/rc.d/named reload
Reloading named config files.

Note that all of the commands discussed above will only take action if the particular service is enabled in /etc/rc.conf. It is possible to bypass this requirement by prepending one to the command, as in:

# /etc/rc.d/httpd start
$httpd is not enabled - see rc.conf(5).
Use the following if you wish to perform the operation:
  /etc/rc.d/httpd onestart
# /etc/rc.d/httpd onestart
Starting httpd.

The above command will allow you to start the httpd(8) service one time. To stop a service that has been started in this manner, pass onestop to the script.

Order/dependencies of start determined by rcorder

The startup system of every Unix system determines, in one way or another, the order in which services are started. On some Unix systems this is done by numbering the files and/or putting them in separate run level directories. Solaris relies on wildcards like /etc/rc[23].d/S* being sorted numerically when expanded. Some simply put all the commands that should be started into a single monolithic script (this is the traditional BSD method, and is what NetBSD did before the rc.d system). On modern NetBSD this is done by the rc.d scripts and their contents. Please note that NetBSD does not have multiple runlevels as found in SysV-style systems like Solaris and Linux.

At the beginning of each rc.d script there is a series of commented out lines that have one of the following items in them:

These describe the dependencies of that particular script and allow rcorder to easily work either up or down as the situation requires. As an example, here is the ordering information contained in /etc/rc.d/nfsd:

...
# PROVIDE: nfsd
# REQUIRE: rpcbind mountd
...

Here we can see that this script provides the nfsd service and that it requires rpcbind and mountd to be running first. The rcorder(8) utility is used at system startup time to read through all the rc.d scripts and determine the order in which they should be run.

rc.d scripts of additional services

Packages you install additionally won't be listed in the rc.conf(5) manpage. Packages installing services which can be started with an rc.d script tell you so after they are installed, along with the variable that is used for starting them (usually, it has the same name as the service itself).

Then, you usually have to copy them from /usr/pkg/share/examples/rc.d to /etc/rc.d for rc to automatically find them, or add the line

rc_directories="/etc/rc.d /usr/pkg/share/examples/rc.d"

to your /etc/rc.conf.

If you forgot the name of the service variable, you can have a look at the rc.d script itself. The variable rcvar (usually set to $name) will tell you. E.g., to find the name of variable to start fscd, run

$ grep ^rcvar /etc/rc.d/fscd
rcvar=${name}
$ grep ^name /etc/rc.d/fscd   # Aaaw, no direct rcvar.
name="fscd"

Thus, you need in your /etc/rc.conf the entry:

fscd="YES"

Additional Reading

Luke Mewburn, one of the principal designers of the rc.d system, gave a presentation on the system at USENIX 2001. It is available in PDF format.

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