Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

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

NAME
     rc.subr --	functions used by system shell scripts

SYNOPSIS
     . /etc/rc.subr

     backup_file action	file current backup

     checkyesno	var

     check_pidfile pidfile procname [interpreter]

     check_process procname [interpreter]

     collapse_backslash_newline

     err exitval message

     load_rc_config command

     load_rc_config_var	command	var

     mount_critical_filesystems	type

     no_rc_postprocess command [arguments]

     print_rc_metadata string

     print_rc_normal [-n] string

     rc_usage command [...]

     reverse_list item [...]

     run_rc_command argument [parameters]

     run_rc_script file	argument

     stop_boot

     twiddle

     wait_for_pids [pid	[...]]

     warn message

     yesno_to_truefalse	var

DESCRIPTION
     rc.subr contains commonly used shell script functions which are used by
     various scripts such as rc(8), and	the periodic system services which are
     controlled	by daily.conf(5), monthly.conf(5), security.conf(5), and
     weekly.conf(5).

     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.

	   action 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
		   current.

	   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-
	   tive.

	   Note	that the warning message shown by this function	when var is
	   not set references a	manual page where the user can find more in-
	   formation.  Its name	is picked up from the rcvar_manpage variable.

     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
	   check_pidfile.

     collapse_backslash_newline
	   Copy	input to output, collapsing <backslash><newline> to nothing,
	   but leaving other backslashes alone.

     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.

     load_rc_config command
	   Source in the rc.conf(5) 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
	   script.

     load_rc_config_var	command	var
	   Read	the rc.conf(5) variable	var for	command	and set	in the current
	   shell, using	load_rc_config in a sub-shell to prevent unwanted side
	   effects from	other variable assignments.

     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.

     no_rc_postprocess command [arguments]
	   Execute the specified command with the specified arguments, in such
	   a way that its output bypasses the post-processor that rc(8)	uses
	   for most commands.  This implies that the output will not appear in
	   the /var/run/rc.log file, and will appear on	the console regardless
	   of the value	of rc_silent.  This is expected	to be useful for in-
	   teractive commands, and this	mechanism is automatically used	by
	   run_rc_command when a script	contains the rcorder(8)	keyword
	   "interactive".

	   If invoked from a context that does not appear to be	under the con-
	   trol	of rc(8), then the command is executed without special treat-
	   ment.

     print_rc_metadata string
	   Print the specified string in such a	way that it should be handled
	   as meta-data	by the rc(8) post-processor.  If invoked from a	con-
	   text	that does not appear to	be under the control of	rc(8), then
	   the string is discarded.

	   Any rc.d(8) script may invoke this function with an argument	that
	   begins with "note:",	followed by one	line of	arbitrary text;	the
	   text	will be	logged by rc(8)	but will not be	displayed on the con-
	   sole.

	   The use of arguments	that do	not begin with "note:" is reserved for
	   internal use	by rc(8) and rc.subr.

     print_rc_normal [-n] string
	   Print the specified string in such a	way that it should be handled
	   as normal output by the rc(8) post-processor.  If invoked from a
	   context that	does not appear	to be under the	control	of rc(8), then
	   the string is printed to standard output.

	   If the -n flag is specified,	then the string	is printed without a
	   newline.

	   Intended use	cases include:

	   +o   An rc.d script can use "print_rc_normal -n" to print a partial
	       line in such a way that it appears immediately instead of being
	       buffered	by rc(8)'s post-processor.

	   +o   An rc.d script that is run via the no_rc_postprocess function
	       (so most	of its output is invisible to rc(8)'s post-processor)
	       can use print_rc_normal to force	some of	its output to be seen
	       by the post-processor.

     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 [parameter	...]
	   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.	 The optional set of
	   parameters is passed	verbatim to the	command, but not to its
	   pre/post hooks.

	   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	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.	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
	   extra_commands.

	   argument may	have one of the	following prefixes which alters	its
	   operation:

		 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.

		 rcvar_manpage
			   The manual page containing information about	rcvar.
			   It will be part of the warning message shown	when
			   rcvar is undefined.	Defaults to rc.conf(5).

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

		 command_args
			   Optional arguments and/or shell directives for
			   command.

		 command_interpreter
			   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
			   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.

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

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

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

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

		 ${name}_chroot
			   Directory to	chroot(8) to before running command.
			   Only	supported after	/usr is	mounted.

		 ${name}_env
			   List	of additional or modified environment vari-
			   ables to set	when starting command.

		 ${name}_flags
			   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.

		 ${name}_nice
			   nice(1) level to run	command	as.  Only supported
			   after /usr is mounted.

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

		 ${name}_group
			   Group to run	the chrooted command as.

		 ${name}_groups
			   Comma separated list	of supplementary groups	to run
			   the chrooted	command	with.

		 argument_cmd
			   Shell commands which	override the default method
			   for argument.

		 argument_precmd
			   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
			   checks.

		 argument_postcmd
			   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.

		 sig_reload
			   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 doesn't 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.
		 argument_postcmd.

	   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
		shell.

	   5.	If file	contains the rcorder(8)	keyword	"interactive", then
		the command is executed	using no_rc_postprocess.

     stop_boot
	   Prevent booting to multiuser	mode.  If the autoboot variable	is
	   `yes', then a SIGTERM signal	is sent	to the parent process (which
	   is assumed to be rc(8)).  Otherwise,	the shell exits	with status 1.

     twiddle
	   Display one of the characters `/, -,	\, |', followed	by a
	   backspace.  Repeated	calls to this function will create the appear-
	   ance	of a spinning symbol, as a different character is displayed on
	   each	call.  Output is to /dev/tty, so this function may be useful
	   even	inside a script	whose output has been redirected.

     wait_for_pids [pid	[...]]
	   Wait	until all of the provided pids don't 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.

     yesno_to_truefalse	var
	   Change the value of the specified variable from any of the forms
	   acceptable to the checkyesno	function, to "true" or "false".

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

SEE ALSO
     rc.conf(5), rc(8)

HISTORY
     rc.subr appeared in NetBSD	1.3.  The rc.d(8) support functions appeared
     in	NetBSD 1.5.  Support for the rc(8) post-processor appeared in
     NetBSD 6.0.

BSD				August 11, 2011				   BSD

NAME | SYNOPSIS | DESCRIPTION | FILES | SEE ALSO | HISTORY

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=rc.subr&sektion=8&manpath=NetBSD+6.0>

home | help