Import sysutils/sysrc from the ports tree (current version 5.1). Importing

disconnected under the WITH_BSDCONFIG flag (a good idea since this version of
sysrc(8) indeed requires the `sysrc.subr' module installed by bsdconfig(8)).

Multiple reasons sysrc should not simply continue to live in ports. The most
important being that it is tightly coupled with the base.

Approved by:	adrian (co-mentor)

3 files changed, 921 insertions, 0 deletions

diff --git a/usr.sbin/sysrc/Makefile b/usr.sbin/sysrc/Makefile
new file mode 100644
index 0000000..38c52ee
--- /dev/null
+++ b/usr.sbin/sysrc/Makefile
@@ -0,0 +1,13 @@
+# $FreeBSD$
+
+NO_OBJ=
+
+SCRIPTS= sysrc
+
+MAN= sysrc.8
+
+beforeinstall:
+	mkdir -p ${DESTDIR}${SCRIPTSDIR}
+	mkdir -p ${DESTDIR}${MANDIR}8
+
+.include <bsd.prog.mk>
diff --git a/usr.sbin/sysrc/sysrc b/usr.sbin/sysrc/sysrc
new file mode 100644
index 0000000..24a304d
--- /dev/null
+++ b/usr.sbin/sysrc/sysrc
@@ -0,0 +1,618 @@
+#!/bin/sh
+#-
+# Copyright (c) 2010-2012 Devin Teske
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# $FreeBSD$
+#
+############################################################ INCLUDES
+
+BSDCFG_SHARE="/usr/share/bsdconfig"
+[ "$_COMMON_SUBR" ] || . $BSDCFG_SHARE/common.subr || exit 1
+[ "$_SYSRC_SUBR"  ] || f_include $BSDCFG_SHARE/sysrc.subr
+
+############################################################ CONFIGURATION
+
+#
+# Default verbosity.
+#
+: ${SYSRC_VERBOSE:=}
+
+############################################################ GLOBALS
+
+#
+# Options
+#
+DELETE=
+DESCRIBE=
+IGNORE_UNKNOWNS=
+JAIL=
+QUIET=
+ROOTDIR=
+SHOW_ALL=
+SHOW_EQUALS=
+SHOW_FILE=
+SHOW_NAME=1
+SHOW_VALUE=1
+
+############################################################ FUNCTIONS
+
+# die [ $fmt [ $opts ... ]]
+#
+# Optionally print a message to stderr before exiting with failure status.
+#
+die()
+{
+	local fmt="$1"
+	[ $# -gt 0 ] && shift 1
+	[  "$fmt"  ] && f_err "$fmt\n" "$@"
+
+	exit $FAILURE
+}
+
+# usage
+#
+# Prints a short syntax statement and exits.
+#
+usage()
+{
+	f_err "Usage: %s [OPTIONS] name[=value] ...\n" "$pgm"
+	f_err "Try \`%s --help' for more information.\n" "$pgm"
+	die
+}
+
+# help
+#
+# Prints a full syntax statement and exits.
+#
+help()
+{
+	local optfmt="\t%-11s%s\n"
+	local envfmt="\t%-17s%s\n"
+
+	f_err "Usage: %s [OPTIONS] name[=value] ...\n" "$pgm"
+
+	f_err "OPTIONS:\n"
+	f_err "$optfmt" "-a" \
+	      "Dump a list of all non-default configuration variables."
+	f_err "$optfmt" "-A" \
+	      "Dump a list of all configuration variables (incl. defaults)."
+	f_err "$optfmt" "-d" \
+	      "Print a description of the given variable."
+	f_err "$optfmt" "-D" \
+	      "Show default value(s) only (this is the same as setting"
+	f_err "$optfmt" "" \
+	      "RC_CONFS to NULL or passing \`-f' with a NULL file-argument)."
+	f_err "$optfmt" "-e" \
+	      "Print query results as \`var=value' (useful for producing"
+	f_err "$optfmt" "" \
+	      "output to be fed back in). Ignored if \`-n' is specified."
+	f_err "$optfmt" "-f file" \
+	      "Operate on the specified file(s) instead of rc_conf_files."
+	f_err "$optfmt" "" \
+	      "Can be specified multiple times for additional files."
+	f_err "$optfmt" "-F" \
+	      "Show only the last rc.conf(5) file each directive is in."
+	f_err "$optfmt" "-h" \
+	      "Print a short usage statement to stderr and exit."
+	f_err "$optfmt" "--help" \
+	      "Print this message to stderr and exit."
+	f_err "$optfmt" "-i" \
+	      "Ignore unknown variables."
+	f_err "$optfmt" "-j jail" \
+	      "The jid or name of the jail to operate within (overrides"
+	f_err "$optfmt" "" \
+	      "\`-R dir'; requires jexec(8))."
+	f_err "$optfmt" "-n" \
+	      "Show only variable values, not their names."
+	f_err "$optfmt" "-N" \
+	      "Show only variable names, not their values."
+	f_err "$optfmt" "-q" \
+	      "Quiet. Ignore previous \`-v' and/or SYSRC_VERBOSE."
+	f_err "$optfmt" "-R dir" \
+	      "Operate within the root directory \`dir' rather than \`/'."
+	f_err "$optfmt" "-v" \
+	      "Verbose. Print the pathname of the specific rc.conf(5)"
+	f_err "$optfmt" "" \
+	      "file where the directive was found."
+	f_err "$optfmt" "-x" \
+	      "Remove variable(s) from specified file(s)."
+	f_err "\n"
+
+	f_err "ENVIRONMENT:\n"
+	f_err "$envfmt" "RC_CONFS" \
+	      "Override default rc_conf_files (even if set to NULL)."
+	f_err "$envfmt" "RC_DEFAULTS" \
+	      "Location of \`/etc/defaults/rc.conf' file."
+	f_err "$envfmt" "SYSRC_VERBOSE" \
+	      "Default verbosity. Set to non-NULL to enable."
+
+	die
+}
+
+# jail_depend
+#
+# Dump dependencies such as language-file variables and include files to stdout
+# to be piped-into sh(1) running via jexec(8)/chroot(8). As a security measure,
+# this prevents existing language files and library files from being loaded in
+# the jail. This also relaxes the requirement to have these files in every jail
+# before sysrc can be used on said jail.
+#
+jail_depend()
+{
+	#
+	# Indicate that we are jailed
+	#
+	echo export _SYSRC_JAILED=1
+
+	#
+	# Print i18n language variables (their current values are sanitized
+	# and re-printed for interpretation so that the i18n language files
+	# do not need to exist within the jail).
+	#
+	local var val
+	for var in \
+		msg_cannot_create_permission_denied \
+		msg_permission_denied \
+		msg_previous_syntax_errors \
+	; do
+		val=$( eval echo \"\$$var\" |
+			awk '{ gsub(/'\''/, "'\''\\'\'\''"); print }' )
+		echo $var="'$val'"
+	done
+
+	#
+	# Print include dependencies
+	#
+	cat $BSDCFG_SHARE/common.subr
+	cat $BSDCFG_SHARE/sysrc.subr
+}
+
+############################################################ MAIN SOURCE
+
+#
+# Perform sanity checks
+#
+[ $# -gt 0 ] || usage
+
+#
+# Check for `--help' command-line option
+#
+( # Operate in sub-shell to protect $@ in parent
+	while [ $# -gt 0 ]; do
+		case "$1" in
+		--help) exit 1;;
+		-[fRj]) # These flags take an argument
+			shift 1;;
+		esac
+		shift 1
+	done
+	exit 0
+) || help
+
+#
+# Process command-line flags
+#
+while getopts aAdDef:Fhij:nNqR:vxX flag; do
+	case "$flag" in
+	a) SHOW_ALL=${SHOW_ALL:-1};;
+	A) SHOW_ALL=2;;
+	d) DESCRIBE=1;;
+	D) RC_CONFS=;;
+	e) SHOW_EQUALS=1;;
+	f) RC_CONFS="$RC_CONFS${RC_CONFS:+ }$OPTARG";;
+	F) SHOW_FILE=1;;
+	h) usage;;
+	i) IGNORE_UNKNOWNS=1;;
+	j) [ "$OPTARG" ] || die \
+	   	"%s: Missing or null argument to \`-j' flag" "$pgm"
+	   JAIL="$OPTARG";;
+	n) SHOW_NAME=;;
+	N) SHOW_VALUE=;;
+	q) QUIET=1 SYSRC_VERBOSE=;;
+	R) [ "$OPTARG" ] || die \
+	   	"%s: Missing or null argument to \`-R' flag" "$pgm"
+	   ROOTDIR="$OPTARG";;
+	v) SYSRC_VERBOSE=1 QUIET=;;
+	x) DELETE=${DELETE:-1};;
+	X) DELETE=2;;
+	\?) usage;;
+	esac
+done
+shift $(( $OPTIND - 1 ))
+
+#
+# [More] Sanity checks (e.g., "sysrc --")
+#
+[ $# -eq 0 -a ! "$SHOW_ALL" ] && usage
+
+#
+# Taint-check all rc.conf(5) files
+#
+errmsg="$pgm: Exiting due to previous syntax errors"
+if ( : ${RC_CONFS?} ) > /dev/null 2>&1; then
+	( for i in $RC_CONFS; do
+	  	[ -e "$i" ] || continue
+	  	/bin/sh -n "$i" || exit $FAILURE
+	  done
+	  exit $SUCCESS
+	) || die "$errmsg"
+else
+	/bin/sh -n "$RC_DEFAULTS" || die "$errmsg"
+	( . "$RC_DEFAULTS"
+	  for i in $rc_conf_files; do
+	  	[ -e "$i" ] || continue
+	  	/bin/sh -n "$i" || exit $FAILURE
+	  done
+	  exit $SUCCESS
+	) || die "$errmsg"
+fi
+
+#
+# Process `-x' (and secret `-X') command-line options
+#
+errmsg="$pgm: \`-x' option incompatible with \`-a'/\`-A' options"
+errmsg="$errmsg (use \`-X' to override)"
+if [ "$DELETE" -a "$SHOW_ALL" ]; then
+	[ "$DELETE" = "2" ] || die "$errmsg"
+fi
+
+#
+# Process `-e', `-n', and `-N' command-line options
+#
+SEP=': '
+[ "$SHOW_EQUALS" ] && SEP='="'
+[ "$SHOW_NAME" ] || SHOW_EQUALS=
+[ "$SYSRC_VERBOSE" = "0" ] && SYSRC_VERBOSE=
+if [ ! "$SHOW_VALUE" ]; then
+	SHOW_NAME=1
+	SHOW_EQUALS=
+fi
+
+#
+# Process `-j jail' and `-R dir' command-line options
+#
+if [ "$JAIL" -o "$ROOTDIR" ]; then
+	#
+	# Reconstruct the arguments that we want to carry-over
+	#
+	args="
+		${SYSRC_VERBOSE:+-v}
+		${QUIET:+-q}
+		$( [ "$DELETE" = "1" ] && echo \ -x )
+		$( [ "$DELETE" = "2" ] && echo \ -X )
+		$( [ "$SHOW_ALL" = "1" ] && echo \ -a )
+		$( [ "$SHOW_ALL" = "2" ] && echo \ -A )
+		${DESCRIBE:+-d}
+		${SHOW_EQUALS:+-e}
+		${IGNORE_UNKNOWNS:+-i}
+		$( [ "$SHOW_NAME"  ] || echo \ -n )
+		$( [ "$SHOW_VALUE" ] || echo \ -N )
+		$( [ "$SHOW_FILE"  ] && echo \ -F )
+	"
+	if ( : ${RC_CONFS?} ) > /dev/null 2>&1; then
+		args="$args -f '$RC_CONFS'"
+	fi
+	for arg in "$@"; do
+		args="$args '$arg'"
+	done
+
+	#
+	# If both are supplied, `-j jail' supercedes `-R dir'
+	#
+	if [ "$JAIL" ]; then
+		#
+		# Re-execute ourselves with sh(1) via jexec(8)
+		#
+		( echo set -- $args
+		  jail_depend
+		  cat $0
+		) | env - RC_DEFAULTS="$RC_DEFAULTS" \
+		    	/usr/sbin/jexec "$JAIL" /bin/sh
+		exit $?
+	elif [ "$ROOTDIR" ]; then
+		#
+		# Make sure that the root directory specified is not to any
+		# running jails.
+		#
+		# NOTE: To maintain backward compatibility with older jails on
+		# older systems, we will not perform this check if either the
+		# jls(1) or jexec(8) utilities are missing.
+		#
+		if f_have jexec && f_have jls; then
+			jid="`jls jid path | \
+			(
+				while read JID JROOT; do
+					[ "$JROOT" = "$ROOTDIR" ] || continue
+					echo $JID
+				done
+			)`"
+
+			#
+			# If multiple running jails match the specified root
+			# directory, exit with error.
+			#
+			if [ "$jid" -a "${jid%[$IFS]*}" != "$jid" ]; then
+				die "%s: %s: %s" "$pgm" "$ROOTDIR" \
+				    "$( echo "Multiple jails claim this" \
+				             "directory as their root." \
+				             "(use \`-j jail' instead)" )"
+			fi
+
+			#
+			# If only a single running jail matches the specified
+			# root directory, implicitly use `-j jail'.
+			#
+			if [ "$jid" ]; then
+				#
+				# Re-execute outselves with sh(1) via jexec(8)
+				#
+				( echo set -- $args
+				  jail_depend
+				  cat $0
+				) | env - RC_DEFAULTS="$RC_DEFAULTS" \
+					/usr/sbin/jexec "$jid" /bin/sh
+				exit $?
+			fi
+
+			# Otherwise, fall through and allow chroot(8)
+		fi
+
+		#
+		# Re-execute ourselves with sh(1) via chroot(8)
+		#
+		( echo set -- $args
+		  jail_depend
+		  cat $0
+		) | env - RC_DEFAULTS="$RC_DEFAULTS" \
+		    	/usr/sbin/chroot "$ROOTDIR" /bin/sh
+		exit $?
+	fi
+fi
+
+#
+# Process `-a' or `-A' command-line options
+#
+if [ "$SHOW_ALL" ]; then
+	#
+	# Get a list of variables that are currently set in the rc.conf(5)
+	# files (included `/etc/defaults/rc.conf') by performing a call to
+	# source_rc_confs() in a clean environment.
+	#
+	( # Operate in a sub-shell to protect the parent environment
+		#
+		# Set which variables we want to preserve in the environment.
+		# Append the pipe-character (|) to the list of internal field
+		# separation (IFS) characters, allowing us to use the below
+		# list both as an extended grep (-E) pattern and argument list
+		# (required to first get f_clean_env() to preserve these in the
+		# environment and then later to prune them from the list of
+		# variables produced by set(1)).
+		#
+		IFS="$IFS|"
+		EXCEPT="IFS|EXCEPT|PATH|RC_DEFAULTS|OPTIND|DESCRIBE|SEP"
+		EXCEPT="$EXCEPT|DELETE|SHOW_ALL|SHOW_EQUALS|SHOW_NAME"
+		EXCEPT="$EXCEPT|SHOW_VALUE|SHOW_FILE|SYSRC_VERBOSE|RC_CONFS"
+		EXCEPT="$EXCEPT|pgm|SUCCESS|FAILURE"
+		EXCEPT="$EXCEPT|f_sysrc_desc_awk|f_sysrc_delete_awk"
+
+		#
+		# Clean the environment (except for our required variables)
+		# and then source the required files.
+		#
+		f_clean_env --except $EXCEPT
+		if [ -f "$RC_DEFAULTS" -a -r "$RC_DEFAULTS" ]; then
+			. "$RC_DEFAULTS"
+
+			#
+			# If passed `-a' (rather than `-A'), re-purge the
+			# environment, removing the rc.conf(5) defaults.
+			#
+			[ "$SHOW_ALL" = "1" ] \
+				&& f_clean_env --except rc_conf_files $EXCEPT
+
+			#
+			# If `-f file' was passed, set $rc_conf_files to an
+			# explicit value, modifying the default behavior of
+			# source_rc_confs().
+			#
+			( : ${RC_CONFS?} ) > /dev/null 2>&1 &&
+				rc_conf_files="$RC_CONFS"
+
+			source_rc_confs
+
+			#
+			# If passed `-a' (rather than `-A'), remove
+			# `rc_conf_files' unless it was defined somewhere
+			# other than rc.conf(5) defaults.
+			#
+			[ "$SHOW_ALL" = "1" -a \
+			  "$( f_sysrc_find rc_conf_files )" = "$RC_DEFAULTS" \
+			] \
+			&& unset rc_conf_files
+		fi
+
+		for NAME in $( set |
+			awk -F= '/^[[:alpha:]_][[:alnum:]_]*=/ {print $1}' |
+			grep -Ev "^($EXCEPT)$"
+		); do
+			#
+			# If enabled, describe rather than expand value
+			#
+			if [ "$DESCRIBE" ]; then
+				echo "$NAME: $( f_sysrc_desc "$NAME" )"
+				continue
+			fi
+
+			#
+			# If `-F' is passed, find it and move on
+			#
+			if [ "$SHOW_FILE" ]; then
+				[ "$SHOW_NAME" ] && echo -n "$NAME: "
+				f_sysrc_find "$NAME"
+				continue
+			fi
+
+			#
+			# If `-X' is passed, delete the variables
+			#
+			if [ "$DELETE" = "2" ]; then
+				f_sysrc_delete "$NAME"
+				continue
+			fi
+
+			[ "$SYSRC_VERBOSE" ] && \
+				echo -n "$( f_sysrc_find "$NAME" ): "
+
+			#
+			# If `-N' is passed, simplify the output
+			#
+			if [ ! "$SHOW_VALUE" ]; then
+				echo "$NAME"
+				continue
+			fi
+
+			echo "${SHOW_NAME:+$NAME$SEP}$(
+			      f_sysrc_get "$NAME" )${SHOW_EQUALS:+\"}"
+
+		done
+	)
+
+	#
+	# Ignore the remainder of positional arguments.
+	#
+	exit $SUCCESS
+fi
+
+#
+# Process command-line arguments
+#
+while [ $# -gt 0 ]; do
+	NAME="${1%%=*}"
+
+	[ "$DESCRIBE" ] && \
+		echo "$NAME: $( f_sysrc_desc "$NAME" )"
+
+	case "$1" in
+	*=*)
+		#
+		# Like sysctl(8), if both `-d' AND "name=value" is passed,
+		# first describe, then attempt to set
+		#
+
+		if [ "$SYSRC_VERBOSE" ]; then
+			file=$( f_sysrc_find "$NAME" )
+			[ "$file" = "$RC_DEFAULTS" -o ! "$file" ] && \
+				file=$( f_sysrc_get 'rc_conf_files%%[$IFS]*' )
+			echo -n "$file: "
+		fi
+
+		#
+		# If `-x' or `-X' is passed, delete the variable and ignore the
+		# desire to set some value
+		#
+		if [ "$DELETE" ]; then
+			f_sysrc_delete "$NAME"
+			shift 1
+			continue
+		fi
+
+		#
+		# If `-N' is passed, simplify the output
+		#
+		if [ ! "$SHOW_VALUE" ]; then
+			echo "$NAME"
+			f_sysrc_set "$NAME" "${1#*}"
+		else
+			if [ "$SHOW_FILE" ]; then
+				before=$( f_sysrc_find "$NAME" )
+			else
+				before=$( f_sysrc_get "$NAME" )
+			fi
+			if f_sysrc_set "$NAME" "${1#*=}"; then
+				if [ "$SHOW_FILE" ]; then
+					after=$( f_sysrc_find "$NAME" )
+					echo -n "${SHOW_NAME:+$NAME$SEP}"
+					echo -n "$before${SHOW_EQUALS:+\"}"
+					echo " -> $after"
+				else
+					after=$( f_sysrc_get "$NAME" )
+					echo -n "${SHOW_NAME:+$NAME$SEP}"
+					echo "$before -> $after"
+				fi
+			fi
+		fi
+		;;
+	*)
+		if ! IGNORED="$( f_sysrc_get "$NAME?" )"; then
+			[ "$IGNORE_UNKNOWNS" ] \
+				|| echo "$pgm: unknown variable '$NAME'"
+			shift 1
+			continue
+		fi
+
+		#
+		# Like sysctl(8), when `-d' is passed,
+		# desribe it rather than expanding it
+		#
+
+		if [ "$DESCRIBE" ]; then
+			shift 1
+			continue
+		fi
+
+		#
+		# If `-x' or `-X' is passed, delete the variable
+		#
+		if [ "$DELETE" ]; then
+			f_sysrc_delete "$NAME"
+			shift 1
+			continue
+		fi
+
+		#
+		# If `-F' is passed, find it and move on
+		#
+		if [ "$SHOW_FILE" ]; then
+			[ "$SHOW_NAME" ] && echo -n "$NAME: "
+			f_sysrc_find "$NAME"
+			shift 1
+			continue
+		fi
+
+		[ "$SYSRC_VERBOSE" ] && \
+			echo -n "$( f_sysrc_find "$NAME" ): "
+
+		#
+		# If `-N' is passed, simplify the output
+		#
+		if [ ! "$SHOW_VALUE" ]; then
+			echo "$NAME"
+		else
+			echo "${SHOW_NAME:+$NAME$SEP}$(
+			      f_sysrc_get "$NAME" )${SHOW_EQUALS:+\"}"
+		fi
+	esac
+	shift 1
+done
diff --git a/usr.sbin/sysrc/sysrc.8 b/usr.sbin/sysrc/sysrc.8
new file mode 100644
index 0000000..19ffe93
--- /dev/null
+++ b/usr.sbin/sysrc/sysrc.8
@@ -0,0 +1,290 @@
+.\" Copyright (c) 2011-2012 Devin Teske
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd Aug 24, 2012
+.Dt SYSRC 8
+.Os
+.Sh NAME
+.Nm sysrc
+.Nd safely edit system rc files
+.Sh SYNOPSIS
+.Nm
+.Op Fl dDeFhinNqvx
+.Op Fl f Ar file
+.Op Fl j Ar jail | Fl R Ar dir
+.Ar name Ns Op = Ns Ar value
+.Ar ...
+.Nm
+.Op Fl dDeFhinNqvx
+.Op Fl f Ar file
+.Op Fl j Ar jail | Fl R Ar dir
+.Fl a | A
+.Sh DESCRIPTION
+The
+.Nm
+utility retrieves
+.Xr rc.conf 5
+variables from the collection of system rc files and allows processes with
+appropriate privilege to change values in a safe and effective manner.
+.Pp
+The following options are available:
+.Bl -tag -width indent+
+.It Fl a
+Dump a list of all non-default configuration variables.
+.It Fl A
+Dump a list of all configuration variables 
+.Pq incl. defaults .
+.It Fl d
+Print a description of the given variable.
+.It Fl D
+Show default value(s) only (this is the same as setting RC_CONFS to NULL or
+passing `-f' with a NULL file-argument).
+.It Fl e
+Print query results as
+.Ql var=value
+.Pq useful for producing output to be fed back in .
+Ignored if 
+.Fl n
+is specified.
+.It Fl f Ar file
+Operate on the specified file(s) instead of the files obtained by reading the 
+.Sq rc_conf_files 
+entry in the 
+.Ev RC_DEFAULTS 
+file.
+This option can be specified multiple times for additional files.
+.It Fl F
+Show only the last
+.Xr rc.conf 5
+file each directive is in.
+.It Fl h
+Print a short usage message to stderr and exit.
+.It Fl -help
+Print a full usage statement to stderr and exit.
+.It Fl i
+Ignore unknown variables.
+.It Fl j Ar jail
+The 
+.Ar jid
+or name of the 
+.Ar jail 
+to operate within 
+.Pq overrides So Fl R Ar dir Sc ; requires Xr jexec 8 .
+.It Fl n
+Show only variable values, not their names.
+.It Fl N
+Show only variable names, not their values.
+.It Fl q
+Quiet. Ignore previous
+.Fl v
+and/or
+.Ev SYSRC_VERBOSE .
+.It Fl R Ar dir
+Operate within the root directory 
+.Pq Sq Ar dir
+rather than 
+.Pq Sq / .
+.It Fl v
+Verbose. Print the pathname of the specific 
+.Xr rc.conf 5 
+file where the directive was found.
+.It Fl x
+Remove variable(s) from specified file(s).
+.El
+.Pp
+This utility works similar to
+.Xr sysctl 8 .
+It shares the `-e' and `-n' options
+.Pq detailed above
+and also has the same
+.Ql name[=value]
+syntax for querying/setting configuration options.
+.Pp
+However, while
+.Xr sysctl 8
+serves to query/modify MIBs in the entrant kernel,
+.Xr sysrc 8
+instead works on values in the system
+.Xr rc.conf 5
+configuration files.
+.Pp
+The list of system configuration files is configured in the file
+.Ql /etc/defaults/rc.conf
+within the variable 
+.Ql rc_conf_files ,
+which by-default contains a space-separated list of pathnames. On all FreeBSD
+systems, this defaults to the value "/etc/rc.conf /etc/rc.conf.local". Each
+pathname is sourced in-order upon startup. It is in the same fashion that
+.Nm
+sources the configuration files before returning the value of the given
+variable.
+.Pp
+When supplied a variable name,
+.Nm
+will return the value of the variable. If the variable does not appear in any
+of the configured
+.Ql rc_conf_files ,
+an error is printed and error status is returned.
+.Pp
+When changing values of a given variable, it does not matter if the variable
+appears in any of the
+.Ql rc_conf_files
+or not. If the variable does not appear in any of the files, it is appended to
+the end of the first pathname in the
+.Ql rc_conf_files
+variable. Otherwise,
+.Nm
+will replace only the last-occurrence in the last-file found to contain the
+variable. This gets the value to take effect next boot without heavily
+modifying these integral files (yet taking care not to allow the file to
+grow unwieldy should
+.Nm
+be called repeatedly).
+.Sh ENVIRONMENT
+The following environment variables are referenced by
+.Nm :
+.Bl -tag -width ".Ev SYSRC_VERBOSE"
+.It Ev RC_CONFS
+Override default
+.Ql rc_conf_files
+.Pq even if set to NULL .
+.It Ev RC_DEFAULTS
+Location of 
+.Ql /etc/defaults/rc.conf
+file.
+.It Ev SYSRC_VERBOSE
+Default verbosity. Set to non-NULL to enable.
+.El
+.Sh DEPENDENCIES
+The following standard commands are required by 
+.Nm :
+.Pp
+.Xr awk 1 ,
+.Xr cat 1 ,
+.Xr chmod 1 ,
+.Xr chown 8 ,
+.Xr env 1 ,
+.Xr grep 1 ,
+.Xr jexec 8 ,
+.Xr jls 1 ,
+.Xr mktemp 1 ,
+.Xr mv 1 ,
+.Xr rm 1 ,
+.Xr sh 1 ,
+.Xr stat 1 ,
+.Xr tail 1
+.Sh FILES
+.Bl -tag -width ".Pa /etc/defaults/rc.conf" -compact
+.It Pa /etc/defaults/rc.conf
+.It Pa /etc/rc.conf
+.It Pa /etc/rc.conf.local
+.El
+.Sh EXAMPLES
+Below are some simple examples of how
+.Nm
+can be used to query certain values from the
+.Xr rc.conf 5
+collection of system configuration files:
+.Pp
+.Nm
+sshd_enable
+.Dl returns the value of $sshd_enable, usually YES or NO .
+.Pp
+.Nm
+defaultrouter
+.Dl returns IP address of default router Pq if configured .
+.Pp
+Working on other files, such as
+.Xr crontab 5 :
+.Pp
+.Nm
+-f /etc/crontab MAILTO
+.Dl returns the value of the MAILTO setting Pq if configured .
+.Pp
+In addition to the above syntax,
+.Nm
+also supports inline
+.Xr sh 1
+PARAMETER expansion for changing the way values are reported, shown below:
+.Pp
+.Nm
+\&'hostname%%.*'
+.Dl returns $hostname up to (but not including) first `.' .
+.Pp
+.Nm
+\&'network_interfaces%%[$IFS]*'
+.Dl returns first word of $network_interfaces .
+.Pp
+.Nm
+\&'ntpdate_flags##*[$IFS]'
+.Dl returns last word of $ntpdate_flags (time server address) .
+.Pp
+.Nm
+usbd_flags-"default"
+.Dl returns $usbd_flags or "default" if unset or NULL .
+.Pp
+.Nm
+cloned_interfaces+"alternate"
+.Dl returns "alternate" if $cloned_interfaces is set .
+.Pp
+.Nm
+\&'#kern_securelevel'
+.Dl returns length in characters of $kern_securelevel .
+.Pp
+.Nm
+\&'hostname?'
+.Dl returns NULL and error status 2 if $hostname is unset Pq or if set, returns the value of $hostname with no error status .
+.Pp
+.Nm
+\&'hostname:?'
+.Dl returns NULL and error status 2 if $hostname is unset or NULL Pq or if set and non-NULL, returns value without error status .
+.Sh LIMITATIONS
+The
+.Nm
+utility presently does not support the
+.Ql rc.conf.d
+collection of system configuration files
+.Pq which requires a service name to be known during execution .
+.Pp
+This will be corrected by a future enhancement.
+.Sh SEE ALSO
+.Xr jail 8 ,
+.Xr jexec 8 ,
+.Xr jls 1 ,
+.Xr rc 8 ,
+.Xr rc.conf 5 ,
+.Xr sysctl 8
+.Sh HISTORY
+A
+.Nm
+utility first appeared in
+.Bx 10.0 .
+.Sh AUTHORS
+.An Devin Teske Aq dteske@FreeBSD.org
+.Sh THANKS TO
+Brandon Gooch, Garrett Cooper, Julian Elischer, Pawel Jakub Dawidek,
+Cyrille Lefevre, Ross West, Stefan Esser, Marco Steinbach, and Jilles Tjoelker
+for suggestions and help.