rc
, rc.local
,
rc.shutdown
, rc.d/
—
startup and shutdown scripts
rc
is the command script which controls the startup of
various services, and is invoked by
init(8) as part of the process of
entering the automatic reboot to multi-user startup, or after the single user
mode shell has exited. If init(8)
is starting the automatic reboot process, rc
is
invoked with the argument of ‘autoboot’.
rc.local
is a command script to which
local boot-time actions can be added. It is (nearly) the last thing invoked
by rc
during a normal boot.
rc.shutdown
is the command script which
shuts down various services, and is invoked by
shutdown(8) as part of the
process of shutting down the system.
rc.d/
is the directory which contains
various sh(1) scripts, one for
each service, which are called by rc
at startup,
rc.shutdown
at shutdown, and as necessary during
system operation to stop, start, restart, reload, or otherwise control the
service.
- Source /etc/rc.subr to load various
rc.subr(8) shell functions
to use.
- 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.
- 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.
- Calls each script in turn using
run_rc_script
()
(from rc.subr(8)), which
sets $1
to ‘start’, and sources the
script in a sub-shell. If the script has a ‘.sh’ suffix then
it is sourced directly into the current shell.
- 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.
- Source /etc/rc.subr to load various
rc.subr(8) shell functions
to use.
- 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.
- Calls each script in turn using
run_rc_script
()
(from rc.subr(8)), which
sets $1
to ‘stop’, and sources the
script in a sub-shell. If the script has a ‘.sh’ suffix then
it is sourced directly into the current shell.
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 (network) and
dhcpcd.
- 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).
- inline.sh
- Scripts that are sourced into the current shell rather than a sub-shell
have a ‘.sh’ suffix. Extreme care
must be taken in using this, as the startup sequence will terminate if the
script causes the current shell process to terminate.
/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.
- service
- Scripts that are sourced in a sub-shell. 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.
- /etc/rc
- Startup script called by
init(8).
- /etc/rc.d/
- Directory containing control scripts for each service.
- /etc/rc.local
- Local startup script.
- /etc/rc.shutdown
- Shutdown script called by
shutdown(8).
- /etc/rc.subr
- Contains rc.subr(8)
functions used by various scripts.
- /etc/rc.conf
- System startup configuration file.
- /var/run/rc.log
- Log file created by
rc
.
rc.conf(5),
init(8),
rc.subr(8),
rcorder(8),
reboot(8),
shutdown(8)
Luke Mewburn,
The Design and Implementation of the NetBSD rc.d
system, Proceedings of the FREENIX Track: 2001 USENIX
Annual Technical Conference, USENIX Association,
http://www.usenix.org/publications/library/proceedings/usenix01/freenix01/full_papers/mewburn/mewburn.pdf,
June 25-30, 2001.
The rc
command appeared in
4.0BSD. The /etc/rc.d support
was implemented in NetBSD 1.5 by Luke
Mewburn ⟨lukem@NetBSD.org⟩. The post-processor, support
for rc_silent, and saving output to a file, was
implemented in NetBSD 6.0 by Alan
Barrett.