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RC.SUBR(8)		  BSD System Manager's Manual		    RC.SUBR(8)

     rc.subr --	functions used by system shell scripts

     . /etc/rc.subr

     backup_file action	file current backup
     checkyesno	var
     check_pidfile pidfile procname [interpreter]
     check_process procname [interpreter]
     debug message
     err exitval message
     force_depend name
     info message
     load_rc_config command
     mount_critical_filesystems	type
     rc_usage command ...
     reverse_list item ...
     run_rc_command argument
     run_rc_script file	argument
     set_rcvar [base]
     wait_for_pids [pid	...]
     warn message

     The rc.subr script	contains commonly used shell script functions and
     variable definitions which	are used by various scripts such as rc(8).
     Scripts required by ports in /usr/local/etc/rc.d will also	eventually be
     rewritten to make use of it.

     The rc.subr functions were	mostly imported	from NetBSD 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:

	   Its value will be either "FreeBSD" or "NetBSD", depending on	which
	   OS it is running on.

	   The path to the sysctl(8) command.

	   The path and	argument list to display only the sysctl(8) values in-
	   stead of a name=value pair.

	   The path and	argument to write or modify sysctl(8) values.

     The rc.subr functions are accessed	by sourcing /etc/rc.subr into the cur-
     rent shell.

     The following shell functions are available:

     backup_file action	file current backup
	   Make	a backup copy of file into current.  If	the rc.conf(5) vari-
	   able	backup_uses_rcs	is "YES", use rcs(1) to	archive	the previous
	   version of current, otherwise save the previous version of current
	   as backup.

	   The action argument may be one of the following:

	   add	   file	is now being backed up by or possibly re-entered into
		   this	backup mechanism.  current is created, and if neces-
		   sary, the rcs(1) files are created as well.

	   update  file	has changed and	needs to be backed up.	If current ex-
		   ists, it is copied to backup	or checked into	rcs(1) (if the
		   repository file is old), and	then file is copied to

	   remove  file	is no longer being tracked by this backup mechanism.
		   If rcs(1) is	being used, an empty file is checked in	and
		   current is removed, otherwise current is moved to backup.

     checkyesno	var
	   Return 0 if var is defined to "YES",	"TRUE",	"ON", or `1'.  Return
	   1 if	var is defined to "NO",	"FALSE", "OFF",	or `0'.	 Otherwise,
	   warn	that var is not	set correctly.	The values are case insensi-

     check_pidfile pidfile procname [interpreter]
	   Parses the first word of the	first line of pidfile for a PID, and
	   ensures that	the process with that PID is running and its first ar-
	   gument matches procname.  Prints the	matching PID if	successful,
	   otherwise nothing.  If interpreter is provided, parse the first
	   line	of procname, ensure that the line is of	the form

		 #! interpreter	[...]

	   and use interpreter with its	optional arguments and procname	ap-
	   pended as the process string	to search for.

     check_process procname [interpreter]
	   Prints the PIDs of any processes that are running with a first ar-
	   gument that matches procname.  interpreter is handled as per

     debug message
	   Display a debugging message to stderr, log it to the	system log us-
	   ing logger(1), and return to	the caller.  The error message con-
	   sists of the	script name (from $0), followed	by ": DEBUG: ",	and
	   then	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
	   rc.conf(5) variable rc_debug.

     err exitval message
	   Display an error message to stderr, log it to the system log	using
	   logger(1), and exit with an exit value of exitval.  The error mes-
	   sage	consists of the	script name (from $0), followed	by ": ERROR:
	   ", and then message.

     force_depend name
	   Output an advisory message and force	the name service to start.
	   The name argument is	the basename(1)	component of the path to the
	   script, usually /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.

     info message
	   Display an informational message to stdout, and log it to the sys-
	   tem log using logger(1).  The message consists of the script	name
	   (from $0), followed by ": INFO: ", and then message.	 The display
	   of this informational output	can be turned on or off	by the
	   rc.conf(5) variable rc_info.

     load_rc_config command
	   Source in the configuration files for command.  First, /etc/rc.conf
	   is sourced if it has	not yet	been read in.  Then,
	   /etc/rc.conf.d/command is sourced if	it is an existing file.	 The
	   latter may also contain other variable assignments to override
	   run_rc_command arguments defined by the calling script, to provide
	   an easy mechanism for an administrator to override the behaviour of
	   a given rc.d(8) script without requiring the	editing	of that

     mount_critical_filesystems	type
	   Go through a	list of	critical file systems, as found	in the
	   rc.conf(5) variable critical_filesystems_type, mounting each	one
	   that	is not currently mounted.

     rc_usage command ...
	   Print a usage message for $0, with commands being the list of valid
	   arguments prefixed by "[fast|force|one]".

     reverse_list item ...
	   Print the list of items in reverse order.

     run_rc_command argument
	   Run the argument method for the current rc.d(8) script, based on
	   the settings	of various shell variables.  run_rc_command is ex-
	   tremely flexible, and allows	fully functional rc.d(8) scripts to be
	   implemented in a small amount of shell code.

	   argument is searched	for in the list	of supported commands, which
	   may be one of:

		 start	  Start	the service.  This should check	that the ser-
			  vice 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	FreeBSD	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 is

		 restart  Perform a stop then a	start.	Defaults to displaying
			  the process ID of the	program	(if running).

		 rcvar	  Display which	rc.conf(5) variables are used to con-
			  trol the startup of the service (if any).

	   If pidfile or procname is set, also support:

		 poll	  Wait for the command to exit.

		 status	  Show the status of the process.

	   Other supported commands are	listed in the optional variable

	   argument may	have one of the	following prefixes which alters	its

		 fast	Skip the check for an existing running process,	and
			sets rc_fast=YES.

		 force	Skip the checks	for rcvar being	set to "YES", and sets
			rc_force=YES.  This ignores argument_precmd returning
			non-zero, and ignores any of the required_* tests
			failing, and always returns a zero exit	status.

		 one	Skip the checks	for rcvar being	set to "YES", but per-
			forms all the other prerequisite tests.

	   run_rc_command uses the following shell variables to	control	its
	   behaviour.  Unless otherwise	stated,	these are optional.

		 name	   The name of this script.  This is not optional.

		 rcvar	   The value of	rcvar is checked with checkyesno to
			   determine if	this method should be run.

		 command   Full	path to	the command.  Not required if
			   argument_cmd	is defined for each supported keyword.

			   Optional arguments and/or shell directives for

			   command is started with

				 #! command_interpreter	[...]
			   which results in its	ps(1) command being

				 command_interpreter [...] command

			   so use that string to find the PID(s) of the	run-
			   ning	command	rather than command.

			   Extra commands/keywords/arguments supported.

		 pidfile   Path	to PID file.  Used to determine	the PID(s) of
			   the running command.	 If pidfile is set, use

				 check_pidfile $pidfile	$procname

			   to find the PID.  Otherwise,	if command is set, use

				 check_process $procname

			   to find the PID.

		 procname  Process name	to check for.  Defaults	to the value
			   of command.

			   Check for the existence of the listed directories
			   before running the default start method.

			   Check for the readability of	the listed files be-
			   fore	running	the default start method.

			   Perform checkyesno on each of the list variables
			   before running the default start method.

			   Directory to	cd to before running command, if
			   ${name}_chroot is not provided.

			   Directory to	chroot(8) to before running command.
			   Only	supported after	/usr is	mounted.

			   Arguments to	call command with.  This is usually
			   set in rc.conf(5), and not in the rc.d(8) script.
			   The environment variable `flags' can	be used	to
			   override this.

			   nice(1) level to run	command	as.  Only supported
			   after /usr is mounted.

			   User	to run command as, using chroot(8).  if
			   ${name}_chroot is set, otherwise uses su(1).	 Only
			   supported after /usr	is mounted.

			   Group to run	the chrooted command as.

			   Comma separated list	of supplementary groups	to run
			   the chrooted	command	with.

			   Shell commands which	override the default method
			   for argument.

			   Shell commands to run just before running
			   argument_cmd	or the default method for 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
			   required_* checks and process (non-)existence

			   Shell commands to run if running argument_cmd or
			   the default method for argument returned a zero
			   exit	code.

		 sig_stop  Signal to send the processes	to stop	in the default
			   stop	method.	 Defaults to SIGTERM.

			   Signal to send the processes	to reload in the de-
			   fault reload	method.	 Defaults to SIGHUP.

	   For a given method argument,	if argument_cmd	is not defined,	then a
	   default method is provided by run_rc_command:

		 Argument  Default method

		 start	   If command is not running and checkyesno rcvar suc-
			   ceeds, start	command.

		 stop	   Determine the PIDs of command with check_pidfile or
			   check_process (as appropriate), kill	sig_stop those
			   PIDs, and run wait_for_pids on those	PIDs.

		 reload	   Similar to stop, except that	it uses	sig_reload in-
			   stead, and does not run wait_for_pids.

		 restart   Runs	the stop method, then the start	method.

		 status	   Show	the PID	of command, or some other script spe-
			   cific status	operation.

		 poll	   Wait	for command to exit.

		 rcvar	   Display which rc.conf(5) variable is	used (if any).
			   This	method always works, even if the appropriate
			   rc.conf(5) variable is set to "NO".

	   The following variables are available to the	methods	(such as
	   argument_cmd) as well as after run_rc_command has completed:

		 rc_arg	   Argument provided to	run_rc_command,	after fast and
			   force processing has	been performed.

		 rc_flags  Flags to start the default command with.  Defaults
			   to ${name}_flags, unless overridden by the environ-
			   ment	variable `flags'.  This	variable may be
			   changed by the argument_precmd method.

		 rc_pid	   PID of command (if appropriate).

		 rc_fast   Not empty if	"fast" prefix was used.

		 rc_force  Not empty if	"force"	prefix was used.

     run_rc_script file	argument
	   Start the script file with an argument of argument, and handle the
	   return value	from the script.

	   Various shell variables are unset before file is started:

		 name, command,	command_args, command_interpreter,
		 extra_commands, pidfile, rcvar, required_dirs,
		 required_files, required_vars,	argument_cmd, argument_precmd.

	   The startup behaviour of file depends upon the following checks:

	   1.	If file	ends in	.sh, it	is sourced into	the current shell.

	   2.	If file	appears	to be a	backup or scratch file (e.g., with a
		suffix of ~, #,	.OLD, or .orig), ignore	it.

	   3.	If file	is not executable, ignore it.

	   4.	If the rc.conf(5) variable rc_fast_and_loose is	empty, source
		file in	a sub shell, otherwise source file into	the current

     set_rcvar [base]
	   Set the variable name required to start a service.  In FreeBSD a
	   daemon is usually controlled	by an rc.conf(5) variable consisting
	   of a	daemon's name postfixed	by the string "_enable".  This is not
	   the case in NetBSD.	When the following line	is included in a


	   This	function will use the value of the $name variable, which
	   should be defined by	the calling script, to construct the appropri-
	   ate rc.conf(5) knob.	 If the	base argument is set it	will use base
	   instead of $name.

     wait_for_pids [pid	...]
	   Wait	until all of the provided pids do not exist any	more, printing
	   the list of outstanding pids	every two seconds.

     warn message
	   Display a warning message to	stderr and log it to the system	log
	   using logger(1).  The warning message consists of the script	name
	   (from $0), followed by ": WARNING: ", and then message.

     /etc/rc.subr  The rc.subr file resides in /etc.

     rc.conf(5), rc(8)

     The rc.subr script	appeared in NetBSD 1.3.	 The rc.d(8) support functions
     appeared in NetBSD	1.5.  The rc.subr script first appeared	in
     FreeBSD 5.0.

BSD				January	6, 2004				   BSD


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