path: root/share/man/man8/rc.subr.8

.\" 	$OpenBSD: rc.subr.8,v 1.39 2021/10/31 17:58:28 ajacoutot Exp $
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.\" Copyright (c) 2021 Antoine Jacoutot
.\" Copyright (c) 2011 Robert Nagy, Antoine Jacoutot, Ingo Schwarze
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.Dd $Mdocdate: October 31 2021 $
.Dt RC.SUBR 8
.Os
.Sh NAME
.Nm rc.subr
.Nd daemon control scripts routines
.Sh SYNOPSIS
.Nm daemon Ns = Ns Ar path_to_executable
.Nm .\&
.Pa /etc/rc.d/rc.subr
.Nm rc_cmd
.Ar action
.Sh DESCRIPTION
Apart from a few notable exceptions, rc scripts must follow this
naming policy:
.Pp
.Bl -enum -compact
.It
When possible, use the same name as the
.Nm daemon
it is referring to.
.It
It must follow
.Xr ksh 1
variable naming: begin with an alphabetic or underscore character, followed by
one or more alphanumeric or underscore characters.
Dashes
.Pq Sq -
have to be converted to
underscores
.Pq Sq _ .
.El
.Pp
Every script under
.Pa /etc/rc.d
follows this pattern:
.Pp
.Bl -enum -compact
.It
Define the
.Va daemon
variable.
.It
Define service-specific defaults for one or more
.Va daemon_*
variables (optional).
.It
Source
.Nm ,
which defines default shell functions and variable values.
.It
Override the
.Va pexp
variable or any of the
.Ic rc_*
functions and set the
.Va rc_bg
or
.Va rc_reload
variables, if needed.
.It
Define an
.Ic rc_pre
and/or
.Ic rc_post
function, if needed.
.It
Call the
.Ic rc_cmd
function as
.Dq "rc_cmd $1" .
.El
.Pp
The following shell functions are defined by
.Nm :
.Bl -tag -width rc_reload
.It Ic rc_cmd Ar action
Run the
.Ar action
for the current
.Nm rc.d
script, based on the settings of various shell variables.
.Ic rc_cmd
is extremely flexible, and allows fully functional
.Nm rc.d
scripts to be implemented in a small amount of shell code.
For a given
.Ar action ,
if the
.Ic rc_${action}
function is not defined, then a default function is provided by
.Nm rc.subr .
In addition actions can be disabled by setting the
.Va rc_${action}
variable to
.Dq NO .
For example, if
.Dq rc_reload=NO
is set in the
.Nm rc.d
script, and
.Ic rc_cmd
is called for the reload action, an error will be raised.
Similarly, the special variable
.Va rc_usercheck
must be set to
.Dq NO
if the
.Cm check
.Ar action
requires root privileges.
.Pp
The
.Ar action
argument can be
.Cm start ,
.Cm stop ,
.Cm reload ,
.Cm restart ,
or
.Cm check :
.Bl -tag -width restart
.It Ic check
Call
.Ic rc_check .
Return 0 if the daemon is running or 1 if it is not.
.It Ic start
Check that the service is running by calling
.Ic rc_check .
If it's not running, call
.Ic rc_pre
if it exists, then
.Ic rc_start .
.It Ic stop
Check that the service is running by calling
.Ic rc_check .
If it is running,
call
.Ic rc_stop
and wait up to 30 seconds for the daemon to properly shutdown.
If successful, run
.Ic rc_post
if it exists.
.It Ic restart
Run the
.Ar action
argument
.Cm stop ,
then if successful run
.Cm start .
.It Ic reload
Check that the service is running by calling
.Ic rc_check .
If it is running,
call
.Ic rc_reload .
.El
.It Ic rc_check
Search for processes of the service with
.Xr pgrep 1
using the regular expression given in the
.Va pexp
variable.
.It Ic rc_start
Start the daemon.
Defaults to:
.Bd -literal -offset indent
${rcexec} "${daemon} ${daemon_flags}"
.Ed
.It Ic rc_stop
Stop the daemon.
Send a
.Dv SIGTERM
signal using
.Xr pkill 1
on the regular expression given in the
.Va pexp
variable.
.It Ic rc_reload
Send a
.Dv SIGHUP
signal using
.Xr pkill 1
on the regular expression given in the
.Va pexp
variable.
One has to make sure that sending
.Dv SIGHUP
to a daemon will have the desired effect,
i.e. that it will reload its configuration.
.El
.Sh ENVIRONMENT
.Ic rc_cmd
uses the following shell variables to control its behaviour.
.Bl -tag -width "daemon_timeout"
.It Va daemon
The path to the daemon, optionally followed by one or more
whitespace separated arguments.
Arguments included here are always used, even if
.Va daemon_flags
is empty.
This variable is required.
It is an error to source
.Nm
without defining
.Va daemon
first.
.It Va daemon_class
Login class to run the daemon with, using
.Xr su 1 .
This is a read only variable that gets set by
.Nm rc.subr
itself.
It searches
.Xr login.conf 5
for a login class that has the same name as the
.Nm rc.d
script itself and uses that.
If no such login class exists then
.Dq daemon
will be used.
.It Va daemon_flags
Arguments to call the daemon with.
.It Ar daemon Ns _logger
Redirect standard output and error to
.Xr logger 1
using the configured priority (e.g. "daemon.info").
.It Va daemon_rtable
Routing table to run the daemon under, using
.Xr route 8 .
.It Va daemon_timeout
Maximum time in seconds to wait for the
.Cm start ,
.Cm stop
and
.Cm reload
actions to return.
This is only guaranteed with the default
.Ic rc_start ,
.Ic rc_stop
and
.Ic rc_reload
functions.
.It Va daemon_user
User to run the daemon as, using
.Xr su 1 .
.It Va pexp
A regular expression to be passed to
.Xr pgrep 1
in order to find the desired process or to be passed to
.Xr pkill 1
to stop it.
By default this variable contains the
.Va daemon
and
.Va daemon_flags
variables.
To override the default value, an
.Nm rc.d
script has to redefine this variable
.Em after
sourcing
.Nm .
.It Va rc_bg
Can be set to
.Cm YES
in an
.Nm rc.d
script to force starting the daemon in background when using the default
.Ic rc_start .
.It Va rc_reload
Can be set to
.Dq NO
in an
.Nm rc.d
script to disable the reload action if the respective daemon
does not support reloading its configuration.
.Em The same is possible, but almost never useful, for other actions.
.It Va rc_usercheck
Can be set to
.Dq NO
in an
.Nm rc.d
script, if the
.Cm check
action needs root privileges.
.It Va rcexec
Holds the full
.Xr su 1
command used to run the daemon.
Defaults to:
.Pp
.Dl "su -l -c ${daemon_class} -s /bin/sh ${daemon_user} -c"
.El
If
.Va daemon_rtable
is set, the following
.Xr route 8
command is prepended to
.Va rcexec :
.Pp
.Dl "route -T ${daemon_rtable} exec"
.Pp
All
.Va daemon_*
variables are set in the following ways:
.Bl -enum
.It
Global defaults are provided by
.Nm :
.Bd -literal -offset indent
daemon_class=daemon
daemon_flags=
daemon_logger=
daemon_rtable=0
daemon_timeout=30
daemon_user=root
.Ed
.It
Service-specific defaults may be provided in the respective
.Nm rc.d
script
.Em before
sourcing
.Nm ,
thus overriding the global defaults.
.It
As noted in
.Xr rc.d 8 ,
site-specific values provided in
.Xr rc.conf.local 8
for
.Va daemon_flags ,
.Va daemon_logger ,
.Va daemon_rtable ,
.Va daemon_timeout ,
and
.Va daemon_user
will override those defaults.
.El
.Sh FILES
.Bl -tag -width Ds
.It Pa /etc/rc.d/
Directory containing daemon control scripts.
.It Pa /etc/rc.d/rc.subr
Functions and variables used by
.Nm rc.d
scripts.
.It Pa /usr/ports/infrastructure/templates/rc.template
A sample
.Nm rc.d
script.
.El
.Sh SEE ALSO
.Xr rc 8 ,
.Xr rc.conf 8 ,
.Xr rc.d 8
.Sh HISTORY
The
.Nm
framework
first appeared in
.Ox 4.9 .
.Sh AUTHORS
.An -nosplit
The
.Nm
framework was written by
.An Robert Nagy Aq Mt robert@openbsd.org ,
.An Antoine Jacoutot Aq Mt ajacoutot@openbsd.org ,
and
.An Ingo Schwarze Aq Mt schwarze@openbsd.org .