nbd: new package nbd-server

Network block device server allows to export a block device from router
to remote host. This is particularly useful if no network filesystem
server is feasible or direct access to a block device is needed.

It's been tested for nearly a month on ar71xx (TL-WR842ND) and proved to
be very stable and efficient solution.
The package comes with init.d script and conf.d file allowing to
configure most nbd-server options using standard uci interface.

Signed-off-by: Marcin Jurkowski <marcin1j@gmail.com>

net/nbd/files/nbd-server.init

@@ -0,0 +1,108 @@
+#!/bin/sh /etc/rc.common
+# Copyright (C) 2012 OpenWrt.org
+
+START=60
+SERVICE_USE_PID=1
+
+CONFIGFILE="/var/etc/nbd-server.conf"
+
+
+append_plain() {
+	echo "$1" >> $CONFIGFILE
+}
+
+append_val_str() {
+	local resultname="$1"
+	local cfg="$2"
+	local uciname="${3:-$1}"
+	local value=
+
+	config_get value "$cfg" "$uciname"
+
+	if [ -z "$value" ]; then
+		return
+	fi
+	append_plain "$resultname = $value"
+}
+
+append_val_bool() {
+	local resultname="$1"
+	local cfg="$2"
+	local uciname="${3:-$1}"
+	local value=
+
+	config_get_bool value "$cfg" "$uciname"
+	if [ -z "$value" ]; then
+		return
+	fi
+
+	[ $value == 1 ] && value="true" || value="false"
+	append_plain "$resultname = $value"
+}
+
+config_handle_generic() {
+	local cfg="$1"
+
+	append_plain "[generic]"
+	append_val_str user "$cfg"
+	append_val_str group "$cfg"
+	append_val_str port "$cfg"
+	append_val_str listenaddr "$cfg"
+	append_val_bool allowlist "$cfg"
+	append_val_str includedir "$cfg"
+	append_val_bool oldstyle "$cfg"
+
+	config_get_bool SERVICE_ENABLED "$cfg" enabled 0
+}
+
+config_handle_share() {
+	local cfg="$1"
+
+	append_plain
+	append_plain "[$cfg]"
+	append_val_str exportname "$cfg" filename
+	append_val_str timeout "$cfg"
+	append_val_str maxconnections "$cfg"
+	append_val_str authfile "$cfg"
+	append_val_str filesize "$cfg"
+	append_val_str readonly "$cfg"
+	append_val_str multifile "$cfg"
+	append_val_str copyonwrite "$cfg"
+	append_val_bool sparse_cow "$cfg"
+	append_val_bool flush "$cfg"
+	append_val_bool fua "$cfg"
+	append_val_bool rotational "$cfg"
+	append_val_bool sync "$cfg"
+	append_val_bool discard "$cfg"
+	append_val_str prerun "$cfg"
+	append_val_str postrun "$cfg"
+	append_val_str virtstyle "$cfg"
+	append_val_str port "$cfg" oldstyle_port
+	append_val_str listenaddr "$cfg" oldstyle_listenaddr
+}
+
+config_read() {
+
+	mkdir -p $(dirname $CONFIGFILE)
+	echo -n > $CONFIGFILE
+
+	config_load nbd-server
+	config_foreach config_handle_generic nbd-server
+	config_foreach config_handle_share share
+}
+
+start() {
+	config_read
+
+	if [ "$SERVICE_ENABLED" = "1" ]; then
+		service_start /usr/bin/nbd-server \
+			--pid-file /var/run/nbd-server.pid \
+			--config-file=$CONFIGFILE
+	fi
+}
+
+stop() {
+	service_stop /usr/bin/nbd-server
+}
+
+