KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

4 files changed, 729 insertions, 0 deletions

diff --git a/tools/bootconfig/scripts/bconf2ftrace.sh b/tools/bootconfig/scripts/bconf2ftrace.sh
new file mode 100755
index 000000000..850c20734
--- /dev/null
+++ b/tools/bootconfig/scripts/bconf2ftrace.sh
@@ -0,0 +1,301 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+usage() {
+	echo "Ftrace boottime trace test tool"
+	echo "Usage: $0 [--apply|--init] [--debug] BOOTCONFIG-FILE"
+	echo "    --apply: Test actual apply to tracefs (need sudo)"
+	echo "    --init:  Initialize ftrace before applying (imply --apply)"
+	exit 1
+}
+
+[ $# -eq 0 ] && usage
+
+BCONF=
+DEBUG=
+APPLY=
+INIT=
+while [ x"$1" != x ]; do
+	case "$1" in
+	"--debug")
+		DEBUG=$1;;
+	"--apply")
+		APPLY=$1;;
+	"--init")
+		APPLY=$1
+		INIT=$1;;
+	*)
+		[ ! -f $1 ] && usage
+		BCONF=$1;;
+	esac
+	shift 1
+done
+
+if [ x"$APPLY" != x ]; then
+	if [ `id -u` -ne 0 ]; then
+		echo "This must be run by root user. Try sudo." 1>&2
+		exec sudo $0 $DEBUG $APPLY $BCONF
+	fi
+fi
+
+run_cmd() { # command
+	echo "$*"
+	if [ x"$APPLY" != x ]; then # apply command
+		eval $*
+	fi
+}
+
+if [ x"$DEBUG" != x ]; then
+	set -x
+fi
+
+TRACEFS=`grep -m 1 -w tracefs /proc/mounts | cut -f 2 -d " "`
+if [ -z "$TRACEFS" ]; then
+	if ! grep -wq debugfs /proc/mounts; then
+		echo "Error: No tracefs/debugfs was mounted." 1>&2
+		exit 1
+	fi
+	TRACEFS=`grep -m 1 -w debugfs /proc/mounts | cut -f 2 -d " "`/tracing
+	if [ ! -d $TRACEFS ]; then
+		echo "Error: ftrace is not enabled on this kernel." 1>&2
+		exit 1
+	fi
+fi
+
+if [ x"$INIT" != x ]; then
+	. `dirname $0`/ftrace.sh
+	(cd $TRACEFS; initialize_ftrace)
+fi
+
+. `dirname $0`/xbc.sh
+
+######## main #########
+set -e
+
+xbc_init $BCONF
+
+set_value_of() { # key file
+	if xbc_has_key $1; then
+		val=`xbc_get_val $1 1`
+		run_cmd "echo '$val' >> $2"
+	fi
+}
+
+set_array_of() { # key file
+	if xbc_has_key $1; then
+		xbc_get_val $1 | while read line; do
+			run_cmd "echo '$line' >> $2"
+		done
+	fi
+}
+
+compose_synth() { # event_name branch
+	echo -n "$1 "
+	xbc_get_val $2 | while read field; do echo -n "$field; "; done
+}
+
+print_hist_array() { # prefix key
+	__sep="="
+	if xbc_has_key ${1}.${2}; then
+		echo -n ":$2"
+		xbc_get_val ${1}.${2} | while read field; do
+			echo -n "$__sep$field"; __sep=","
+		done
+	fi
+}
+
+print_hist_action_array() { # prefix key
+	__sep="("
+	echo -n ".$2"
+	xbc_get_val ${1}.${2} | while read field; do
+		echo -n "$__sep$field"; __sep=","
+	done
+	echo -n ")"
+}
+
+print_hist_one_action() { # prefix handler param
+	echo -n ":${2}("`xbc_get_val ${1}.${3}`")"
+	if xbc_has_key "${1}.trace"; then
+		print_hist_action_array ${1} "trace"
+	elif xbc_has_key "${1}.save"; then
+		print_hist_action_array ${1} "save"
+	elif xbc_has_key "${1}.snapshot"; then
+		echo -n ".snapshot()"
+	fi
+}
+
+print_hist_actions() { # prefix handler param
+	for __hdr in `xbc_subkeys ${1}.${2} 1 ".[0-9]"`; do
+		print_hist_one_action ${1}.${2}.$__hdr ${2} ${3}
+	done
+	if xbc_has_key ${1}.${2}.${3} ; then
+		print_hist_one_action ${1}.${2} ${2} ${3}
+	fi
+}
+
+print_hist_var() { # prefix varname
+	echo -n ":${2}="`xbc_get_val ${1}.var.${2} | tr -d [:space:]`
+}
+
+print_one_histogram() { # prefix
+	echo -n "hist"
+	print_hist_array $1 "keys"
+	print_hist_array $1 "values"
+	print_hist_array $1 "sort"
+	if xbc_has_key "${1}.size"; then
+		echo -n ":size="`xbc_get_val ${1}.size`
+	fi
+	if xbc_has_key "${1}.name"; then
+		echo -n ":name="`xbc_get_val ${1}.name`
+	fi
+	for __var in `xbc_subkeys "${1}.var" 1`; do
+		print_hist_var ${1} ${__var}
+	done
+	if xbc_has_key "${1}.pause"; then
+		echo -n ":pause"
+	elif xbc_has_key "${1}.continue"; then
+		echo -n ":continue"
+	elif xbc_has_key "${1}.clear"; then
+		echo -n ":clear"
+	fi
+	print_hist_actions ${1} "onmax" "var"
+	print_hist_actions ${1} "onchange" "var"
+	print_hist_actions ${1} "onmatch" "event"
+
+	if xbc_has_key "${1}.filter"; then
+		echo -n " if "`xbc_get_val ${1}.filter`
+	fi
+}
+
+setup_one_histogram() { # prefix trigger-file
+	run_cmd "echo '`print_one_histogram ${1}`' >> ${2}"
+}
+
+setup_histograms() { # prefix trigger-file
+	for __hist in `xbc_subkeys ${1} 1 ".[0-9]"`; do
+		setup_one_histogram ${1}.$__hist ${2}
+	done
+	if xbc_has_key ${1}.keys; then
+		setup_one_histogram ${1} ${2}
+	fi
+}
+
+setup_event() { # prefix group event [instance]
+	branch=$1.$2.$3
+	if [ "$4" ]; then
+		eventdir="$TRACEFS/instances/$4/events/$2/$3"
+	else
+		eventdir="$TRACEFS/events/$2/$3"
+	fi
+	# group enable
+	if [ "$3" = "enable" ]; then
+		run_cmd "echo 1 > ${eventdir}"
+		return
+	fi
+
+	case $2 in
+	kprobes)
+		xbc_get_val ${branch}.probes | while read line; do
+			run_cmd "echo 'p:kprobes/$3 $line' >> $TRACEFS/kprobe_events"
+		done
+		;;
+	synthetic)
+		run_cmd "echo '`compose_synth $3 ${branch}.fields`' >> $TRACEFS/synthetic_events"
+		;;
+	esac
+
+	set_value_of ${branch}.filter ${eventdir}/filter
+	set_array_of ${branch}.actions ${eventdir}/trigger
+
+	setup_histograms ${branch}.hist ${eventdir}/trigger
+
+	if xbc_has_key ${branch}.enable; then
+		run_cmd "echo 1 > ${eventdir}/enable"
+	fi
+}
+
+setup_events() { # prefix("ftrace" or "ftrace.instance.INSTANCE") [instance]
+	prefix="${1}.event"
+	if xbc_has_branch ${1}.event; then
+		for grpev in `xbc_subkeys ${1}.event 2`; do
+			setup_event $prefix ${grpev%.*} ${grpev#*.} $2
+		done
+	fi
+	if xbc_has_branch ${1}.event.enable; then
+		if [ "$2" ]; then
+			run_cmd "echo 1 > $TRACEFS/instances/$2/events/enable"
+		else
+			run_cmd "echo 1 > $TRACEFS/events/enable"
+		fi
+	fi
+}
+
+size2kb() { # size[KB|MB]
+	case $1 in
+	*KB)
+		echo ${1%KB};;
+	*MB)
+		expr ${1%MB} \* 1024;;
+	*)
+		expr $1 / 1024 ;;
+	esac
+}
+
+setup_instance() { # [instance]
+	if [ "$1" ]; then
+		instance="ftrace.instance.${1}"
+		instancedir=$TRACEFS/instances/$1
+	else
+		instance="ftrace"
+		instancedir=$TRACEFS
+	fi
+
+	set_array_of ${instance}.options ${instancedir}/trace_options
+	set_value_of ${instance}.trace_clock ${instancedir}/trace_clock
+	set_value_of ${instance}.cpumask ${instancedir}/tracing_cpumask
+	set_value_of ${instance}.tracing_on ${instancedir}/tracing_on
+	set_value_of ${instance}.tracer ${instancedir}/current_tracer
+	set_array_of ${instance}.ftrace.filters \
+		${instancedir}/set_ftrace_filter
+	set_array_of ${instance}.ftrace.notrace \
+		${instancedir}/set_ftrace_notrace
+
+	if xbc_has_key ${instance}.alloc_snapshot; then
+		run_cmd "echo 1 > ${instancedir}/snapshot"
+	fi
+
+	if xbc_has_key ${instance}.buffer_size; then
+		size=`xbc_get_val ${instance}.buffer_size 1`
+		size=`eval size2kb $size`
+		run_cmd "echo $size >> ${instancedir}/buffer_size_kb"
+	fi
+
+	setup_events ${instance} $1
+	set_array_of ${instance}.events ${instancedir}/set_event
+}
+
+# ftrace global configs (kernel.*)
+if xbc_has_key "kernel.dump_on_oops"; then
+	dump_mode=`xbc_get_val "kernel.dump_on_oops" 1`
+	[ "$dump_mode" ] && dump_mode=`eval echo $dump_mode` || dump_mode=1
+	run_cmd "echo \"$dump_mode\" > /proc/sys/kernel/ftrace_dump_on_oops"
+fi
+
+set_value_of kernel.fgraph_max_depth $TRACEFS/max_graph_depth
+set_array_of kernel.fgraph_filters $TRACEFS/set_graph_function
+set_array_of kernel.fgraph_notraces $TRACEFS/set_graph_notrace
+
+# Per-instance/per-event configs
+if ! xbc_has_branch "ftrace" ; then
+	exit 0
+fi
+
+setup_instance # root instance
+
+if xbc_has_branch "ftrace.instance"; then
+	for i in `xbc_subkeys "ftrace.instance" 1`; do
+		run_cmd "mkdir -p $TRACEFS/instances/$i"
+		setup_instance $i
+	done
+fi
+
diff --git a/tools/bootconfig/scripts/ftrace.sh b/tools/bootconfig/scripts/ftrace.sh
new file mode 100644
index 000000000..cc5250c64
--- /dev/null
+++ b/tools/bootconfig/scripts/ftrace.sh
@@ -0,0 +1,110 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+clear_trace() { # reset trace output
+    echo > trace
+}
+
+disable_tracing() { # stop trace recording
+    echo 0 > tracing_on
+}
+
+enable_tracing() { # start trace recording
+    echo 1 > tracing_on
+}
+
+reset_tracer() { # reset the current tracer
+    echo nop > current_tracer
+}
+
+reset_trigger_file() {
+    # remove action triggers first
+    grep -H ':on[^:]*(' $@ |
+    while read line; do
+        cmd=`echo $line | cut -f2- -d: | cut -f1 -d"["`
+	file=`echo $line | cut -f1 -d:`
+	echo "!$cmd" >> $file
+    done
+    grep -Hv ^# $@ |
+    while read line; do
+        cmd=`echo $line | cut -f2- -d: | cut -f1 -d"["`
+	file=`echo $line | cut -f1 -d:`
+	echo "!$cmd" > $file
+    done
+}
+
+reset_trigger() { # reset all current setting triggers
+    if [ -d events/synthetic ]; then
+        reset_trigger_file events/synthetic/*/trigger
+    fi
+    reset_trigger_file events/*/*/trigger
+}
+
+reset_events_filter() { # reset all current setting filters
+    grep -v ^none events/*/*/filter |
+    while read line; do
+	echo 0 > `echo $line | cut -f1 -d:`
+    done
+}
+
+reset_ftrace_filter() { # reset all triggers in set_ftrace_filter
+    if [ ! -f set_ftrace_filter ]; then
+      return 0
+    fi
+    echo > set_ftrace_filter
+    grep -v '^#' set_ftrace_filter | while read t; do
+	tr=`echo $t | cut -d: -f2`
+	if [ "$tr" = "" ]; then
+	    continue
+	fi
+	if ! grep -q "$t" set_ftrace_filter; then
+		continue;
+	fi
+	name=`echo $t | cut -d: -f1 | cut -d' ' -f1`
+	if [ $tr = "enable_event" -o $tr = "disable_event" ]; then
+	    tr=`echo $t | cut -d: -f2-4`
+	    limit=`echo $t | cut -d: -f5`
+	else
+	    tr=`echo $t | cut -d: -f2`
+	    limit=`echo $t | cut -d: -f3`
+	fi
+	if [ "$limit" != "unlimited" ]; then
+	    tr="$tr:$limit"
+	fi
+	echo "!$name:$tr" > set_ftrace_filter
+    done
+}
+
+disable_events() {
+    echo 0 > events/enable
+}
+
+clear_synthetic_events() { # reset all current synthetic events
+    grep -v ^# synthetic_events |
+    while read line; do
+        echo "!$line" >> synthetic_events
+    done
+}
+
+initialize_ftrace() { # Reset ftrace to initial-state
+# As the initial state, ftrace will be set to nop tracer,
+# no events, no triggers, no filters, no function filters,
+# no probes, and tracing on.
+    disable_tracing
+    reset_tracer
+    reset_trigger
+    reset_events_filter
+    reset_ftrace_filter
+    disable_events
+    [ -f set_event_pid ] && echo > set_event_pid
+    [ -f set_ftrace_pid ] && echo > set_ftrace_pid
+    [ -f set_ftrace_notrace ] && echo > set_ftrace_notrace
+    [ -f set_graph_function ] && echo | tee set_graph_*
+    [ -f stack_trace_filter ] && echo > stack_trace_filter
+    [ -f kprobe_events ] && echo > kprobe_events
+    [ -f uprobe_events ] && echo > uprobe_events
+    [ -f synthetic_events ] && echo > synthetic_events
+    [ -f snapshot ] && echo 0 > snapshot
+    clear_trace
+    enable_tracing
+}
diff --git a/tools/bootconfig/scripts/ftrace2bconf.sh b/tools/bootconfig/scripts/ftrace2bconf.sh
new file mode 100755
index 000000000..8eed445c2
--- /dev/null
+++ b/tools/bootconfig/scripts/ftrace2bconf.sh
@@ -0,0 +1,262 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+usage() {
+	echo "Dump boot-time tracing bootconfig from ftrace"
+	echo "Usage: $0 [--debug] [ > BOOTCONFIG-FILE]"
+	exit 1
+}
+
+DEBUG=
+while [ x"$1" != x ]; do
+	case "$1" in
+	"--debug")
+		DEBUG=$1;;
+	-*)
+		usage
+		;;
+	esac
+	shift 1
+done
+
+if [ x"$DEBUG" != x ]; then
+	set -x
+fi
+
+TRACEFS=`grep -m 1 -w tracefs /proc/mounts | cut -f 2 -d " "`
+if [ -z "$TRACEFS" ]; then
+	if ! grep -wq debugfs /proc/mounts; then
+		echo "Error: No tracefs/debugfs was mounted."
+		exit 1
+	fi
+	TRACEFS=`grep -m 1 -w debugfs /proc/mounts | cut -f 2 -d " "`/tracing
+	if [ ! -d $TRACEFS ]; then
+		echo "Error: ftrace is not enabled on this kernel." 1>&2
+		exit 1
+	fi
+fi
+
+######## main #########
+
+set -e
+
+emit_kv() { # key =|+= value
+	echo "$@"
+}
+
+global_options() {
+	val=`cat $TRACEFS/max_graph_depth`
+	[ $val != 0 ] && emit_kv kernel.fgraph_max_depth = $val
+	if grep -qv "^#" $TRACEFS/set_graph_function $TRACEFS/set_graph_notrace ; then
+		cat 1>&2 << EOF
+# WARN: kernel.fgraph_filters and kernel.fgraph_notrace are not supported, since the wild card expression was expanded and lost from memory.
+EOF
+	fi
+}
+
+kprobe_event_options() {
+	cat $TRACEFS/kprobe_events | while read p args; do
+		case $p in
+		\#*)
+		continue;;
+		r*)
+		cat 1>&2 << EOF
+# WARN: A return probe found but it is not supported by bootconfig. Skip it.
+EOF
+		continue;;
+		esac
+		p=${p#*:}
+		event=${p#*/}
+		group=${p%/*}
+		if [ $group != "kprobes" ]; then
+			cat 1>&2 << EOF
+# WARN: kprobes group name $group is changed to "kprobes" for bootconfig.
+EOF
+		fi
+		emit_kv $PREFIX.event.kprobes.$event.probes += $args
+	done
+}
+
+synth_event_options() {
+	cat $TRACEFS/synthetic_events | while read event fields; do
+		emit_kv $PREFIX.event.synthetic.$event.fields = `echo $fields | sed "s/;/,/g"`
+	done
+}
+
+# Variables resolver
+DEFINED_VARS=
+UNRESOLVED_EVENTS=
+
+defined_vars() { # event-dir
+	grep "^hist" $1/trigger | grep -o ':[a-zA-Z0-9]*='
+}
+referred_vars() {
+	grep "^hist" $1/trigger | grep -o '$[a-zA-Z0-9]*'
+}
+
+event_is_enabled() { # enable-file
+	test -f $1 && grep -q "1" $1
+}
+
+per_event_options() { # event-dir
+	evdir=$1
+	# Check the special event which has no filter and no trigger
+	[ ! -f $evdir/filter ] && return
+
+	if grep -q "^hist:" $evdir/trigger; then
+		# hist action can refer the undefined variables
+		__vars=`defined_vars $evdir`
+		for v in `referred_vars $evdir`; do
+			if echo $DEFINED_VARS $__vars | grep -vqw ${v#$}; then
+				# $v is not defined yet, defer it
+				UNRESOLVED_EVENTS="$UNRESOLVED_EVENTS $evdir"
+				return;
+			fi
+		done
+		DEFINED_VARS="$DEFINED_VARS "`defined_vars $evdir`
+	fi
+	grep -v "^#" $evdir/trigger | while read action active; do
+		emit_kv $PREFIX.event.$group.$event.actions += \'$action\'
+	done
+
+	if [ $GROUP_ENABLED -eq 0 ] && event_is_enabled $evdir/enable; then
+		emit_kv $PREFIX.event.$group.$event.enable
+	fi
+	val=`cat $evdir/filter`
+	if [ "$val" != "none" ]; then
+		emit_kv $PREFIX.event.$group.$event.filter = "$val"
+	fi
+}
+
+retry_unresolved() {
+	unresolved=$UNRESOLVED_EVENTS
+	UNRESOLVED_EVENTS=
+	for evdir in $unresolved; do
+		event=${evdir##*/}
+		group=${evdir%/*}; group=${group##*/}
+		per_event_options $evdir
+	done
+}
+
+event_options() {
+	# PREFIX and INSTANCE must be set
+	if [ $PREFIX = "ftrace" ]; then
+		# define the dynamic events
+		kprobe_event_options
+		synth_event_options
+	fi
+	ALL_ENABLED=0
+	if event_is_enabled $INSTANCE/events/enable; then
+		emit_kv $PREFIX.event.enable
+		ALL_ENABLED=1
+	fi
+	for group in `ls $INSTANCE/events/` ; do
+		[ ! -d $INSTANCE/events/$group ] && continue
+		GROUP_ENABLED=$ALL_ENABLED
+		if [ $ALL_ENABLED -eq 0 ] && \
+		   event_is_enabled $INSTANCE/events/$group/enable ;then
+			emit_kv $PREFIX.event.$group.enable
+			GROUP_ENABLED=1
+		fi
+		for event in `ls $INSTANCE/events/$group/` ;do
+			[ ! -d $INSTANCE/events/$group/$event ] && continue
+			per_event_options $INSTANCE/events/$group/$event
+		done
+	done
+	retry=0
+	while [ $retry -lt 3 ]; do
+		retry_unresolved
+		retry=$((retry + 1))
+	done
+	if [ "$UNRESOLVED_EVENTS" ]; then
+		cat 1>&2 << EOF
+! ERROR: hist triggers in $UNRESOLVED_EVENTS use some undefined variables.
+EOF
+	fi
+}
+
+is_default_trace_option() { # option
+grep -qw $1 << EOF
+print-parent
+nosym-offset
+nosym-addr
+noverbose
+noraw
+nohex
+nobin
+noblock
+trace_printk
+annotate
+nouserstacktrace
+nosym-userobj
+noprintk-msg-only
+context-info
+nolatency-format
+record-cmd
+norecord-tgid
+overwrite
+nodisable_on_free
+irq-info
+markers
+noevent-fork
+nopause-on-trace
+function-trace
+nofunction-fork
+nodisplay-graph
+nostacktrace
+notest_nop_accept
+notest_nop_refuse
+EOF
+}
+
+instance_options() { # [instance-name]
+	if [ $# -eq 0 ]; then
+		PREFIX="ftrace"
+		INSTANCE=$TRACEFS
+	else
+		PREFIX="ftrace.instance.$1"
+		INSTANCE=$TRACEFS/instances/$1
+	fi
+	val=
+	for i in `cat $INSTANCE/trace_options`; do
+		is_default_trace_option $i && continue
+		val="$val, $i"
+	done
+	[ "$val" ] && emit_kv $PREFIX.options = "${val#,}"
+	val="local"
+	for i in `cat $INSTANCE/trace_clock` ; do
+		[ "${i#*]}" ] && continue
+		i=${i%]}; val=${i#[}
+	done
+	[ $val != "local" ] && emit_kv $PREFIX.trace_clock = $val
+	val=`cat $INSTANCE/buffer_size_kb`
+	if echo $val | grep -vq "expanded" ; then
+		emit_kv $PREFIX.buffer_size = $val"KB"
+	fi
+	if grep -q "is allocated" $INSTANCE/snapshot ; then
+		emit_kv $PREFIX.alloc_snapshot
+	fi
+	val=`cat $INSTANCE/tracing_cpumask`
+	if [ `echo $val | sed -e s/f//g`x != x ]; then
+		emit_kv $PREFIX.cpumask = $val
+	fi
+	val=`cat $INSTANCE/tracing_on`
+	if [ "$val" = "0" ]; then
+		emit_kv $PREFIX.tracing_on = 0
+	fi
+
+	val=`cat $INSTANCE/current_tracer`
+	[ $val != nop ] && emit_kv $PREFIX.tracer = $val
+	if grep -qv "^#" $INSTANCE/set_ftrace_filter $INSTANCE/set_ftrace_notrace; then
+		cat 1>&2 << EOF
+# WARN: kernel.ftrace.filters and kernel.ftrace.notrace are not supported, since the wild card expression was expanded and lost from memory.
+EOF
+	fi
+	event_options
+}
+
+global_options
+instance_options
+for i in `ls $TRACEFS/instances` ; do
+	instance_options $i
+done
diff --git a/tools/bootconfig/scripts/xbc.sh b/tools/bootconfig/scripts/xbc.sh
new file mode 100644
index 000000000..1f0ebf50d
--- /dev/null
+++ b/tools/bootconfig/scripts/xbc.sh
@@ -0,0 +1,56 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+# bootconfig utility functions
+
+XBC_TMPFILE=
+XBC_BASEDIR=`dirname $0`
+BOOTCONFIG=${BOOTCONFIG:=$XBC_BASEDIR/../bootconfig}
+if [ ! -x "$BOOTCONFIG" ]; then
+	BOOTCONFIG=`which bootconfig`
+	if [ -z "$BOOTCONFIG" ]; then
+		echo "Erorr: bootconfig command is not found" 1>&2
+		exit 1
+	fi
+fi
+
+xbc_cleanup() {
+	if [ "$XBC_TMPFILE" ]; then
+		rm -f "$XBC_TMPFILE"
+	fi
+}
+
+xbc_init() { # bootconfig-file
+	xbc_cleanup
+	XBC_TMPFILE=`mktemp bconf-XXXX`
+	trap xbc_cleanup EXIT TERM
+
+	$BOOTCONFIG -l $1 > $XBC_TMPFILE || exit 1
+}
+
+nr_args() { # args
+	echo $#
+}
+
+xbc_get_val() { # key [maxnum]
+	if [ "$2" ]; then
+		MAXOPT="-L $2"
+	fi
+	grep "^$1 =" $XBC_TMPFILE | cut -d= -f2- | \
+		sed -e 's/", /" /g' -e "s/',/' /g" | \
+		xargs $MAXOPT -n 1 echo
+}
+
+xbc_has_key() { # key
+	grep -q "^$1 =" $XBC_TMPFILE
+}
+
+xbc_has_branch() { # prefix-key
+	grep -q "^$1" $XBC_TMPFILE
+}
+
+xbc_subkeys() { # prefix-key depth [subkey-pattern]
+	__keys=`echo $1 | sed "s/\./ /g"`
+	__s=`nr_args $__keys`
+	grep "^$1$3" $XBC_TMPFILE | cut -d= -f1| cut -d. -f$((__s + 1))-$((__s + $2)) | uniq
+}