.\" 	$NetBSD: rc.subr.8,v 1.9 2002/07/08 16:14:55 atatat Exp $
.\"	$FreeBSD$
.\"
.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Luke Mewburn.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\"    must display the following acknowledgement:
.\"	This product includes software developed by the NetBSD
.\"	Foundation, Inc. and its contributors.
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.\"    contributors may be used to endorse or promote products derived
.\"    from this software without specific prior written permission.
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.Dd April 18, 2002
.Dt RC.SUBR 8
.Os
.Sh NAME
.Nm rc.subr
.Nd functions used by system shell scripts
.Sh SYNOPSIS
.Bl -item
.It
.Li . /etc/rc.subr
.It
.Ic backup_file Ar action Ar file Ar current Ar backup
.It
.Ic checkyesno Ar var
.It
.Ic check_pidfile Ar pidfile Ar procname Op Ar interpreter
.It
.Ic check_process Ar procname Op Ar interpreter
.It
.Ic debug Ar message
.It
.Ic err Ar exitval Ar message
.It
.Ic force_depend Ar name
.It
.Ic info Ar message
.It
.Ic load_rc_config Ar command
.It
.Ic mount_critical_filesystems Ar type
.It
.Ic rc_usage Ar command Op Ar ...
.It
.Ic reverse_list Ar item Op Ar ...
.It
.Ic run_rc_command Ar argument
.It
.Ic run_rc_script Ar file Ar argument
.It
.Ic set_rcvar Op Ar base
.It
.Ic wait_for_pids Op Ar pid Op Ar ...
.It
.Ic warn Ar message
.El
.Sh DESCRIPTION
.Nm
contains commonly used shell script functions and variable
definitions which are used by various scripts such as
.Xr rc 8 .
Scripts required by ports in
.Pa /usr/local/etc/rc.d
will also eventually
be rewritten to make use of it.
.Pp
The
.Nm
functions were mostly imported from
.Nx
and it is intended that they remain synced between the
two projects. With that in mind there are several variable
definitions that can help in this regard. They are:
.Bl -tag -width 4n
.It Ic OSTYPE
Its value will be either
.Fx
or
.Nx ,
depending on which OS it is running on.
.It Ic SYSCTL
The path to the
.Xr sysctl 8
command.
.It Ic SYSCTL_N
The path and argument list to display only the
.Xr sysctl 8
values instead of a name=value pair.
.It Ic SYSCTL_W
The path and argument to write or modify
.Xr sysctl 8
values.
.El
.Pp
The
.Nm
functions are accessed by sourcing
.Pa /etc/rc.subr
into the current shell.
.Pp
The following shell functions are available:
.Bl -tag -width 4n
.It Xo
.Ic backup_file Ar action Ar file Ar current Ar backup
.Xc
Make a backup copy of
.Ar file
into
.Ar current .
If the
.Xr rc.conf 5
variable
.Sy backup_uses_rcs
is
.Sq YES ,
use
.Xr rcs 1
to archive the previous version of
.Ar current ,
otherwise save the previous version of
.Ar current
as
.Ar backup .
.Pp
.Ar action
may be one of the following:
.Bl -tag -width remove
.It Sy add
.Ar file
is now being backed up by or possibly re-entered into this backup mechanism.
.Ar current
is created, and if necessary, the
.Xr rcs 1
files are created as well.
.It Sy update
.Ar file
has changed and needs to be backed up.
If
.Ar current
exists, it is copied to
.Ar backup
or checked into
.Xr rcs 1
(if the repository file is old),
and then
.Ar file
is copied to
.Ar current .
.It Sy remove
.Ar file
is no longer being tracked by this backup mechanism.
If
.Xr rcs 1
is being used, an empty file is checked in and
.Ar current
is removed,
otherwise
.Ar current
is moved to
.Ar backup .
.El
.It Ic checkyesno Ar var
Return 0 if
.Ar var
is defined to
.Sq YES ,
.Sq TRUE ,
.Sq ON ,
or
.Sq 1 .
Return 1 if
.Ar var
is defined to
.Sq NO ,
.Sq FALSE ,
.Sq OFF ,
or
.Sq 0 .
Otherwise, warn that
.Ar var
is not set correctly.
The values are case insensitive.
.It Xo
.Ic check_pidfile
.Ar pidfile
.Ar procname
.Op Ar interpreter
.Xc
Parses the first word of the first line of
.Ar pidfile
for a PID, and ensures that the process with that PID
is running and its first argument matches
.Ar procname .
Prints the matching PID if successfull, otherwise nothing.
If
.Ar interpreter
is provided, parse the first line of
.Ar procname ,
ensure that the line is of the form
.Dl #! interpreter [...]
and use
.Ar interpreter
with its optional arguments and
.Ar procname
appended as the process string to search for.
.It Ic check_process Ar procname Op Ar interpreter
Prints the PIDs of any processes that are running with a first
argument that matches
.Ar procname .
.Ar interpreter
is handled as per
.Ic check_pidfile .
.It Ic debug Ar message
Display a debugging message to
.Em stderr ,
log it to the system log using
.Xr logger 1 ,
and
return to the caller.
The error message consists of the script name
(from
.Sy $0 ) ,
followed by
.Dq ": DEBUG: " ,
and then
.Ar message .
This function is intended to be used by developers
as an aid to debugging scripts. It can be turned on or off
by the
.Xr rc.conf 5
variable
.Em rc_debug .
.It Ic err Ar exitval Ar message
Display an error message to
.Em stderr ,
log it to the system log
using
.Xr logger 1 ,
and
.Cm exit
with an exit value of
.Ar exitval .
The error message consists of the script name
(from
.Sy $0 ) ,
followed by
.Dq ": ERROR: " ,
and then
.Ar message .
.It Ic force_depend name
Output an advisory message and force the
.Ar name
service to start. The
.Ar name
argument is the
.Xr basename 1 ,
component of the path to the script, usually
.Em /etc/rc.d/name .
If the script fails for any reason it will output a warning
and return with a return value of 1. If it was successful
it will return 0.
.It Ic info Ar message
Display an informational message to
.Em stdout ,
and log it to the system log using
.Xr logger 1 .
The message consists of the script name
(from
.Sy $0 ) ,
followed by
.Dq ": INFO: " ,
and then
.Ar message .
The display of this informational output can be
turned on or off by the
.Xr rc.conf 5
variable
.Em rc_info .
.It Ic load_rc_config Ar command
Source in the configuration files for
.Ar command .
First,
.Pa /etc/rc.conf
is sourced if it has not yet been read in.
Then,
.Pa /etc/rc.conf.d/ Ns Ar command
is sourced if it is an existing file.
The latter may also contain other variable assignments to override
.Ic run_rc_command
arguments defined by the calling script, to provide an easy
mechanism for an administrator to override the behaviour of a given
.Xr rc.d 8
script without requiring the editing of that script.
.It Ic mount_critical_filesystems Ar type
Go through a list of critical file systems,
as found in the
.Xr rc.conf 5
variable
.Sy critical_filesystems_ Ns Ar type ,
mounting each one that
is not currently mounted.
.It Ic rc_usage Ar command Op Ar ...
Print a usage message for
.Sy $0 ,
with
.Ar commands
being the list of valid arguments
prefixed by
.Dq "[fast|force]" .
.It Ic reverse_list Ar item Op Ar ...
Print the list of
.Ar items
in reverse order.
.It Ic run_rc_command Ar argument
Run the
.Ar argument
method for the current
.Xr rc.d 8
script, based on the settings of various shell variables.
.Ic run_rc_command
is extremely flexible, and allows fully functional
.Xr rc.d 8
scripts to be implemented in a small amount of shell code.
.Pp
.Ar argument
is searched for in the list of supported commands, which may be one
of:
.Dl start stop restart rcvar
as well as any word listed in the optional variable
.Sy extra_commands .
If
.Sy pidfile
or
.Sy procname
is set, also allow:
.Dl status poll
.Pp
.Ar argument
may have one of the following prefixes which alters its operation:
.Bl -tag -width "Prefix" -offset indent -compact
.It Sy Prefix
.Sy Operation
.It Li fast
Skip the check for an existing running process,
and sets
.Sy rc_fast=YES .
.It Li force
Skip the checks for
.Sy rcvar
being set to yes,
and sets
.Sy rc_force=YES .
This ignores
.Ar argument Ns Sy _precmd
returning non-zero, and ignores any of the
.Sy required_*
tests failing .
.El
.Pp
.Ic run_rc_command
uses the following shell variables to control its behaviour.
Unless otherwise stated, these are optional.
.Bl -tag -width procname -offset indent
.It Sy name
The name of this script.
This is not optional.
.It Sy rcvar
The value of
.Sy rcvar
is checked with
.Ic checkyesno
to determine if this method should be run.
.It Sy command
Full path to the command.
Not required if
.Ar argument Ns Sy _cmd
is defined for each supported keyword.
.It Sy command_args
Optional arguments and/or shell directives for
.Sy command .
.It Sy command_interpreter
.Sy command
is started with
.Dl #! command_interpreter [...]
which results in its
.Xr ps 1
command being
.Dl command_interpreter [...] command
so use that string to find the PID(s) of the running command
rather than
.Ql command .
.It Sy extra_commands
Extra commands/keywords/arguments supported.
.It Sy pidfile
Path to pid file.
Used to determine the PID(s) of the running command.
If
.Sy pidfile
is set, use
.Dl check_pidfile $pidfile $procname
to find the PID.
Otherwise, if
.Sy command
is set, use
.Dl check_process $procname
to find the PID.
.It Sy procname
Process name to check for.
Defaults to the value of
.Sy command .
.It Sy required_dirs
Check for the existence of the listed directories
before running the default start method.
.It Sy required_files
Check for the readability of the listed files
before running the default start method.
.It Sy required_vars
Perform
.Ic checkyesno
on each of the list variables
before running the default start method.
.It Sy ${name}_chdir
Directory to
.Ic cd
to before running
.Sy command ,
if
.Sy ${name}_chroot
is not provided.
.It Sy ${name}_chroot
Directory to
.Xr chroot 8
to before running
.Sy command .
Only supported after
.Pa /usr
is mounted.
.It Sy ${name}_flags
Arguments to call
.Sy command
with.
This is usually set in
.Xr rc.conf 5 ,
and not in the
.Xr rc.d 8
script.
The environment variable
.Sq Ev flags
can be used to override this.
.It Sy ${name}_nice
.Xr nice 1
level to run
.Sy command
as.
Only supported after
.Pa /usr
is mounted.
.It Sy ${name}_user
User to run
.Sy command
as, using
.Xr chroot 8 .
if
.Sy ${name}_chroot
is set, otherwise
uses
.Xr su 1 .
Only supported after
.Pa /usr
is mounted.
.It Sy ${name}_group
Group to run the chrooted
.Sy command
as.
.It Sy ${name}_groups
Comma separated list of supplementary groups to run the chrooted
.Sy command
with.
.It Ar argument Ns Sy _cmd
Shell commands which override the default method for
.Ar argument .
.It Ar argument Ns Sy _precmd
Shell commands to run just before running
.Ar argument Ns Sy _cmd
or the default method for
.Ar argument .
If this returns a non-zero exit code, the main method is not performed.
If the default method is being executed, this check is performed after
the
.Sy required_*
checks and process (non-)existence checks.
.It Ar argument Ns Sy _postcmd
Shell commands to run if running
.Ar argument Ns Sy _cmd
or the default method for
.Ar argument
returned a zero exit code.
.It Sy sig_stop
Signal to send the processes to stop in the default
.Sy stop
method.
Defaults to
.Dv SIGTERM .
.It Sy sig_reload
Signal to send the processes to reload in the default
.Sy reload
method.
Defaults to
.Dv SIGHUP .
.El
.Pp
For a given method
.Ar argument ,
if
.Ar argument Ns Sy _cmd
is not defined, then a default method is provided by
.Sy run_rc_command :
.Bl -tag -width "argument" -offset indent
.It Sy Argument
.Sy Default method
.It Sy start
If
.Sy command
is not running and
.Ic checkyesno Sy rcvar
succeeds, start
.Sy command .
.It Sy stop
Determine the PIDs of
.Sy command
with
.Ic check_pidfile
or
.Ic check_process
(as appropriate),
.Ic kill Sy sig_stop
those PIDs, and run
.Ic wait_for_pids
on those PIDs.
.It Sy reload
Similar to
.Sy stop ,
except that it uses
.Sy sig_reload
instead, and doesn't run
.Ic wait_for_pids .
.It Sy restart
Runs the
.Sy stop
method, then the
.Sy start
method.
.It Sy status
Show the PID of
.Sy command ,
or some other script specific status operation.
.It Sy poll
Wait for
.Sy command
to exit.
.It Sy rcvar
Display which
.Xr rc.conf 5
variable is used (if any).
This method always works, even if the appropriate
.Xr rc.conf 5
variable is set to
.Sq NO .
.El
.Pp
The following variables are available to the methods
(such as
.Ar argument Ns Sy _cmd )
as well as after
.Ic run_rc_command
has completed:
.Bl -tag -width "rc_flags" -offset indent
.It Sy rc_arg
Argument provided to
.Sy run_rc_command ,
after fast and force processing has been performed.
.It Sy rc_flags
Flags to start the default command with.
Defaults to
.Sy ${name}_flags ,
unless overridden by the environment variable
.Sq Ev flags .
This variable may be changed by the
.Ar argument Ns Sy _precmd
method.
.It Sy rc_pid
PID of
.Sy command
(if appropriate).
.It Sy rc_fast
Not empty if
.Dq fast
prefix was used.
.It Sy rc_force
Not empty if
.Dq force
prefix was used.
.El
.It Ic run_rc_script Ar file Ar argument
Start the script
.Ar file
with an argument of
.Ar argument ,
and handle the return value from the script.
.Pp
Various shell variables are unset before
.Ar file
is started:
.Bd -ragged -offset indent
.Sy name ,
.Sy command ,
.Sy command_args ,
.Sy command_interpreter ,
.Sy extra_commands ,
.Sy pidfile ,
.Sy rcvar ,
.Sy required_dirs ,
.Sy required_files ,
.Sy required_vars ,
.Ar argument Ns Sy _cmd ,
.Ar argument Ns Sy _precmd .
.Ar argument Ns Sy _postcmd .
.Ed
.Pp
The startup behaviour of
.Ar file
depends upon the following checks:
.Bl -enum
.It
If
.Ar file
ends in
.Pa .sh ,
it is sourced into the current shell.
.It
If
.Ar file
appears to be a backup or scratch file
(e.g., with a suffix of
.Sq ~ ,
.Sq # ,
.Sq .OLD ,
or
.Sq .orig ) ,
ignore it.
.It
If
.Ar file
is not executable, ignore it.
.It
If the
.Xr rc.conf 5
variable
.Sy rc_fast_and_loose
is empty,
source
.Ar file
in a sub shell,
otherwise source
.Ar file
into the current shell.
.El
.It Ic set_rcvar Op Ar base
Set the variable name required to start a service. In
.Fx
a daemon is usually controlled by an
.Xr rc.conf 5
variable consisting of a daemon's name postfixed by the string
.Sy "_enable" .
This is not the case in
.Nx .
When the following line is included in a script
.Pp
.Dl rcvar=`set_rcvar`
.Pp
This function will use the value of the
.Sy $name
variable, which should be defined by the calling script, to construct the appropriate
.Xr rc.conf 5
knob. If the
.Ar base
argument is set it will use
.Ar base
instead of
.Sy $name .
.It Ic wait_for_pids Op Ar pid Op Ar ...
Wait until all of the provided
.Ar pids
don't exist any more, printing the list of outstanding
.Ar pids
every two seconds.
.It Ic warn Ar message
Display a warning message to
.Em stderr
and log it to the system log
using
.Xr logger 1 .
The warning message consists of the script name
(from
.Sy $0 ) ,
followed by
.Dq ": WARNING: " ,
and then
.Ar message .
.El
.Sh FILES
.Bl -tag -width /etc/rc.subr -compact
.It Pa /etc/rc.subr
The
.Nm
file resides in
.Pa /etc .
.El
.Sh SEE ALSO
.Xr rc.conf 5 ,
.Xr rc 8
.Sh HISTORY
.Nm
appeared in
.Nx 1.3 .
The
.Xr rc.d 8
support functions appeared in
.Nx 1.5 .
.Nm
first appeared in
.Fx 5.0 .