RC.SUBR(8) FreeBSD 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]
DebugOn tag ...
DebugOff tag ...
debug message
dot file ...
err exitval message
force_depend name
info message
is_verified file
load_kld [-e regex] [-m module] file
load_rc_config [flag] [service]
load_rc_config_var name var
mount_critical_filesystems type
rc_log message
rc_trace level message
rc_usage command ...
reverse_list item ...
run_rc_command argument
run_rc_script file argument
run_rc_scripts [options] file ...
safe_dot file ...
sdot file ...
startmsg [-n] message
vdot file ...
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.
DebugOn tag ...
Enable tracing if not already enabled, and any tag is found in
DEBUG_SH (a comma separated list of tags).
Record the tag that caused it to be enabled in DEBUG_ON, set
DEBUG_DO empty and DEBUG_SKIP to `:'.
See debug.sh(8) for more details.
DebugOff tag ...
Disable tracing if enabled and any tag matches DEBUG_ON, which
means it was the reason tracing was enabled.
Set DEBUG_DO to `:', and DEBUG_ON, DEBUG_SKIP empty.
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.
dot file ...
For reading in unverified files.
Ensure shell verify option is off. This option is only meaningful
when mac_veriexec(4) is active.
Read each file if it exists.
Restore previous state of the verify option.
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 located at /etc/rc.d (scripts stored in other locations such
as /usr/local/etc/rc.d cannot be controlled with force_depend
currently). 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.
is_verified file
If veriexec(8) does not exist, or mac_veriexec(4) is not active,
just return success. Otherwise use veriexec(8) to check if file is
verified. If not verified the return code will be 80 (EAUTH).
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 [flag] [service]
Source in the configuration file(s) for service. If no service is
specified, only the global configuration file(s) will be loaded.
First, /etc/rc.conf is sourced if it has not yet been read in.
Then, /etc/rc.conf.d/service 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.
The function named by load_rc_config_reader (default is dot) is
used to read configuration unless flag is:
-s use sdot to read configuration, because we want verified
configuration or to use safe_dot to read an unverified
configuration.
-v use vdot to read in configuration only if it is verified.
DebugOn will be called with tags derived from name to enable
tracing if any appear in DEBUG_SH.
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_log message
Output message with a timestamp, which is both human readable and
easily parsed for post processing, using:
date "+@ %s [%Y-%m-%d %H:%M:%S %Z] $*"
rc_trace level message
If the file /etc/rc.conf.d/rc_trace exists and is not empty attempt
to set RC_LEVEL based on its content. If the file is empty or does
not contain a value for RC_LEVEL, set it to 0.
If level is greater than or equal to RC_LEVEL pass message to
rc_log.
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. 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. The list is
checked before running start_precmd.
required_files
Check for the readability of the listed files
before running the start method. The list is
checked before running start_precmd.
required_modules
Ensure that the listed kernel modules are loaded
before running the start method. The list is
checked after running start_precmd. 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. The list is
checked after running start_precmd.
${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. Those variables will be passed as arguments
to the env(1) utility unless argument_cmd is
defined. In that case the contents of ${name}_env
will be exported via the export(1) builtin of
sh(1), which puts some limitations on the names of
variables (e.g., a variable name may not start with
a digit).
${name}_env_file
A file to source for environmental variables to run
command with. Note: 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}_offcmd
Shell commands to run during start if a service is
not enabled.
${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.
${name}_setup
Optional command to be run during start, restart,
and reload prior to the respective argument_precmd.
If the command fails for any reason it will output
a warning, but execution will continue.
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.
Call rc_trace to indicate that file is to be run.
However, if is_verified file fails, just return.
DebugOn will be called with tags derived from name and rc_arg to
enable tracing if any of those tags appear in DEBUG_SH.
run_rc_script executes file unless:
1. file ends in .sh and lives in /etc/rc.d.
2. file appears to be a backup or scratch file (e.g., with a
suffix of ~, #, .OLD, ,v, or .orig).
3. file is not executable.
run_rc_scripts [options] file ...
Call run_rc_script for each file, unless it is already recorded as
having been run.
The options are:
--arg arg Pass arg to run_rc_script, default is _boot set by
rc(8).
--break break Stop processing if any file matches any break
safe_dot file ...
Used by sdot when mac_veriexec(4) is active and file is not
verified.
This function limits the input from file to simple variable
assignments with any non-alphanumeric characters replaced with `_'.
sdot file ...
For reading in configuration files. Skip files that do not exist
or are empty. Try using vdot and if that fails (the file is
unverified) fall back to using safe_dot.
startmsg [-n] message
Display a start message to stdout. It should be used instead of
echo(1). The display of this output can be turned off if the
rc.conf(5) variable rc_startmsgs is set to "NO".
stop_boot [always]
Prevent booting to multiuser mode. If the autoboot variable is set
to `yes' (see rc(8) to learn more about autoboot), 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.
vdot file ...
For reading in only verified files.
Ensure shell verify option is on. This option is only meaningful
when mac_veriexec(4) is active, otherwise this function is
effectively the same as dot.
Read in each file if it exists and is_verfied file is successful,
otherwise set return code to 80 (EAUTH).
Restore previous state of the verify option.
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), debug.sh(8), 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.
FreeBSD 15.1-STABLE-HBSD October 23, 2024 RC.SUBR(8)