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NAME    [Toc]    [Back]

     rc.subr -- functions used by system shell scripts

SYNOPSIS    [Toc]    [Back]

     . /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

DESCRIPTION    [Toc]    [Back]

     rc.subr 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:

     OSTYPE    [Toc]    [Back]
	   Its value will be either FreeBSD or NetBSD, depending on which OS
	   it is running on.

     SYSCTL    [Toc]    [Back]
	   The path to the sysctl(8) command.

     SYSCTL_N    [Toc]    [Back]
	   The path and argument list to display only the sysctl(8) values
	   instead of a name=value pair.

     SYSCTL_W    [Toc]    [Back]
	   The path and argument to write or modify sysctl(8) values.

     The rc.subr functions are accessed by sourcing /etc/rc.subr into the current

     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) variable
 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 necessary,
 the rcs(1) files are created as well.

	   update  file has changed and needs to be backed up.	If current
		   exists, 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 insensitive.

     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
	   argument matches procname.  Prints the matching PID if successfull,
	   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
	   appended as the process string to search for.

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

     debug message
	   Display a debugging message to stderr, log it to the system log
	   using logger(1), and return to the caller.  The error message consists
 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 message
 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 system
 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]''.

     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
	   extremely 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 stop restart rcvar
	   as well as any word listed in the optional variable extra_commands.
	   If pidfile or procname is set, also allow:
		 status poll

	   argument may have one of the following prefixes which alters its
		 Prefix  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 .

	   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 running
 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
			   before 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
			   default 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 succeeds,
 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
			   instead, 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 specific
 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 environment
 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 appropriate
 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 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.

FILES    [Toc]    [Back]

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

SEE ALSO    [Toc]    [Back]

     rc.conf(5), rc(8)

HISTORY    [Toc]    [Back]

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

FreeBSD 5.2.1			April 18, 2002			 FreeBSD 5.2.1
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