rc.subr

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_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

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.

     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.  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.

           update  file has changed and needs to be backed up.  If current
                   exists, it is copied to backup and then file is copied to
                   current.

           remove  file is no longer being tracked by this backup mechanism.
                   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
           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
           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 running).

                 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
           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.

                 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.

                 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
                           running 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 start method.

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

                 required_modules
                           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.

                 required_vars
                           Perform checkyesno on each of the list variables
                           before running the 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
                           A list of environment variables to run command
                           with.  This will be passed as arguments to the
                           env(1) utility.

                 ${name}_env_file
                           A file to source for environmental variables to run
                           command with.  Note that all the variables which
                           are being assigned in this file are going to be
                           exported into the environment of command.

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

                 ${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}_limits
                           Resource limits to apply to command.  This will be
                           passed as arguments to the limits(1) utility.  By
                           default, the resource limits are based on the login
                           class defined in ${name}_login_class.

                 ${name}_login_class
                           Login class to use with ${name}_limits.  Defaults
                           to “daemon”.

                 ${name}_oomprotect
                           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.

                 ${name}_program
                           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
                           rc.conf(5).

                 ${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.

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

                 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
                           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:

                                 extra_commands=reload

                 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_service  Path to the service script being executed, in
                             case it needs to re-invoke itself.

                 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.

     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.

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 15, 2019                            BSD