add common functions for the new config file format

git-svn-id: svn://svn.openwrt.org/openwrt/branches/buildroot-ng/openwrt@3751 3c298f89-4303-0410-b956-a3cf2f4a3e73

package/base-files/default/etc/functions.sh

@@ -11,3 +11,53 @@ if_valid () (
 hotplug_dev() {
 	env -i ACTION=$1 INTERFACE=$2 /sbin/hotplug net
 }
+
+config_cb() {
+	return 0
+}
+option_cb() {
+	return 0
+}
+
+config () {
+	config_cb "$@"
+	_C=$((${_C:-0} + 1))
+	export CONFIG_SECTION="${2:-cfg${_C}}"
+	export CONFIG_${CONFIG_SECTION}_TYPE="$1"
+}
+
+option () {
+	local varname="$1" ; shift
+	export CONFIG_${CONFIG_SECTION}_${varname}="$*"
+	option_cb "$varname" "$*"
+}
+
+config_clear() {
+	[ -z "$CONFIG_SECTION" ] && return
+	for oldsetting in `set | grep ^CONFIG_${CONFIG_SECTION}_ | \
+		sed -e 's/\(.*\)=.*$/\1/'` ; do 
+		unset $oldsetting 
+	done
+	unset CONFIG_SECTION
+}
+
+config_load() {
+	local CD=""
+	if [ \! -e "$1" -a -e "/etc/config/$1" ]; then
+		cd /etc/config && local CD=1
+	fi
+	[ -e "$1" ] && . $1
+	${CD:+cd - >/dev/null}
+	${CONFIG_SECTION:+config_cb}
+}
+
+config_get() {
+	case "$3" in
+		"") eval "echo \${CONFIG_${1}_${2}}";;
+		*) eval "$1=\"\${CONFIG_${2}_${3}}\"";;
+	esac
+}
+
+config_set() {
+	export CONFIG_${1}_${2}="${3}"
+}