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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]
     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
     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:

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

     SYSCTL
           The path to the sysctl(8) command.

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

     SYSCTL_W
           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
                   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.

     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
           check_pidfile.

     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 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
           script.

     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
           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 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
                          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
                        performs 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.

                 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
                           before 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}_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
                           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 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
                           instead, 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.
                 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.

     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
           script

                 rcvar=`set_rcvar`

           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.

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

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

HISTORY
     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