Command Section
RC.SUBR(8)              FreeBSD 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_kld [-e regex] [-m module] file
     load_rc_config name
     load_rc_config_var name var
     mount_critical_filesystems type
     rc_usage command ...
     reverse_list item ...
     run_rc_command argument
     run_rc_script file argument
     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.

     They are accessed by sourcing /etc/rc.subr into the current 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)
           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.

           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
                       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 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
           insensitive.  Note: var should be a variable name, not its value;
           checkyesno will expand the variable by itself.

     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 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
           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_kld [-e regex] [-m module] file
           Load file as a kernel module unless it is already loaded.  For the
           purpose of checking the module status, either the exact module name
           can be specified using -m, or an egrep(1) regular expression
           matching the module name can be supplied via -e.  By default, the
           module is assumed to have the same name as file, which is not
           always the case.

     load_rc_config name
           Source in the configuration files for name.  First, /etc/rc.conf is
           sourced if it has not yet been read in.  Then, /etc/rc.conf.d/name
           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 name var
           Read the rc.conf(5) variable var for name 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.

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

     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        Start the service.  This should check that the
                              service 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 not.

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

                 enabled      Return 0 if the service is enabled and 1 if it
                              is not.  This command does not print anything.

                 rcvar        Display which rc.conf(5) variables are used to
                              control 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 performs all the other prerequisite tests.

                 quiet      Inhibits some verbose diagnostics.  Currently,
                            this includes messages "Starting ${name}" (as
                            checked by check_startmsgs inside rc.subr) and
                            errors about usage of services that are not
                            enabled in rc.conf(5).  This prefix also sets
                            rc_quiet=YES.  Please, note: rc_quiet is not
                            intended to completely mask all debug and warning
                            messages, but only certain small classes of them.

           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.  Can be overridden by ${name}_program.

                 command_args  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,

                                     check_pidfile $pidfile $procname

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

                                     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 start method.

                               Check for the readability of the listed files
                               before running the start method.

                               Ensure that the listed kernel modules are
                               loaded before running the start method.  This
                               is done after invoking the commands from
                               start_precmd so that the missing modules are
                               not loaded in vain if the preliminary commands
                               indicate a error condition.  A word in the list
                               can have an optional ``:modname'' or
                               ``~pattern'' suffix.  The modname or pattern
                               parameter is passed to load_kld through a -m or
                               -e option, respectively.  See the description
                               of load_kld in this document for details.

                               Perform checkyesno on each of the list
                               variables before running the 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.

                 ${name}_env   A list of environment variables to run command
                               with.  This will be passed as arguments to
                               env(1) utility.

                 ${name}_fib   FIB Routing Table number to run command with.
                               See setfib(1) for more details.

                               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.

                               protect(1) command from being killed when swap
                               space is exhausted.  If YES is used, no child
                               processes are protected.  If ALL, protect all
                               child processes.

                               Full path to the command.  Overrides command if
                               both are set, but has no effect if command is
                               unset.  As a rule, command should be set in the
                               script while ${name}_program should be set in

                 ${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.

                               Group to run the chrooted command as.

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

                               Commands to be prepended to command.  This is a
                               generic version of ${name}_env, ${name}_fib, or

                 argument_cmd  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 checks.

                               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
                               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 does not run wait_for_pids.
                               Another difference from stop is that reload is
                               not provided by default.  It can be enabled via
                               extra_commands if appropriate:


                 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

           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

                 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

     stop_boot [always]
           Prevent booting to multiuser mode.  If the autoboot variable is set
           to `yes', or checkyesno always indicates a truth value, then a
           SIGTERM signal is sent to the parent process, which is assumed to
           be rc(8).  Otherwise, the shell exits with a non-zero status.

     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.

FreeBSD 11.1-RELEASE-p4        February 4, 2016        FreeBSD 11.1-RELEASE-p4
Command Section