uhttpd: support multiple Lua prefixes

Update to latest git HEAD in order to support configuring multiple
concurrent Lua prefixes in a single uhttpd instance:

  b741dec lua: support multiple Lua prefixes

Additionally rework the init script and update the default configuration
example to treat the lua_prefix option as key=value uci list, similar to
the interpreter extension mapping. Support for the old "option lua_prefix"
plus "option lua_handler" notation is still present.

Finally drop the sed postinstall hack in uhttpd-mod-lua to avoid mangling
files belonging to other packages. Since Lua prefixes have precedence
over CGI prefixes, simply register `/cgi-bin/luci` as Lua handler which
will only become active if both luci-base and uhttpd-mod-lua is installed.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/network/services/uhttpd/Makefile

@@ -12,9 +12,9 @@ PKG_RELEASE:=1
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(PROJECT_GIT)/project/uhttpd.git
-PKG_SOURCE_DATE:=2018-08-21
-PKG_SOURCE_VERSION:=952bf9d754d021ee9c08f9add5c9af53aaaf39ae
-PKG_MIRROR_HASH:=34cd66b4c8b4a384e31f3821a4536854491ed2cd62f49c7ae0b0cd4381f061dd
+PKG_SOURCE_DATE:=2018-08-23
+PKG_SOURCE_VERSION:=b741dec35698a80266fb8206970638e666774a33
+PKG_MIRROR_HASH:=2f7c88ba1b36dd6776a7d954b4c5e96aff288992acf19152a38641c665e261e4
 PKG_MAINTAINER:=Felix Fietkau <nbd@nbd.name>
 PKG_LICENSE:=ISC
 
@@ -107,16 +107,6 @@ define Package/uhttpd-mod-ubus/install
 	$(INSTALL_DATA) ./files/ubus.default $(1)/etc/uci-defaults/00_uhttpd_ubus
 endef
 
-define Package/uhttpd-mod-lua/postinst
-	$(if $(CONFIG_uhttpd_lua),
-	#!/bin/sh
-	if [ -f $${IPKG_INSTROOT}/www/index.html ]
-	then
-		sed -e 's:/cgi-bin::g' -i $${IPKG_INSTROOT}/www/index.html
-	fi
-	,)
-endef
-
 
 $(eval $(call BuildPackage,uhttpd))
 $(eval $(call BuildPackage,uhttpd-mod-lua))

package/network/services/uhttpd/files/uhttpd.config

@@ -49,10 +49,13 @@ config uhttpd main
 #	list interpreter	".php=/usr/bin/php-cgi"
 #	list interpreter	".cgi=/usr/bin/perl"
 
-	# Lua url prefix and handler script.
-	# Lua support is disabled if no prefix given.
-	option lua_prefix	/luci
-	option lua_handler	/usr/lib/lua/luci/sgi/uhttpd.lua
+	# List of prefix->Lua handler mappings.
+	# Any request to an URL beneath the prefix
+	# will be dispatched to the associated Lua
+	# handler script. Lua support is disabled when
+	# no handler mappings are specified. Lua prefix
+	# matches have precedence over the CGI prefix.
+	list lua_prefix		"/cgi-bin/luci=/usr/lib/lua/luci/sgi/uhttpd.lua"
 
 	# Specify the ubus-rpc prefix and socket path.
 #	option ubus_prefix	/ubus

package/network/services/uhttpd/files/uhttpd.init

@@ -74,6 +74,18 @@ create_httpauth() {
 	haveauth=1
 }
 
+append_lua_prefix() {
+	local v="$1"
+	local prefix="${v%%=*}"
+	local handler="${v#*=}"
+
+	if [ "$prefix" != "$handler" ] && [ -n "$prefix" ] && [ -f "$handler" ]; then
+		procd_append_param command -l "$prefix" -L "$handler"
+	else
+		echo "Skipping invalid Lua prefix \"$v\"" >&2
+	fi
+}
+
 start_instance()
 {
 	UHTTPD_CERT=""
@@ -105,10 +117,16 @@ start_instance()
 	append_arg "$cfg" config "-c"
 	append_arg "$cfg" cgi_prefix "-x"
 	[ -f /usr/lib/uhttpd_lua.so ] && {
-		config_get handler "$cfg" lua_handler
-		[ -f "$handler" ] && append_arg "$cfg" lua_prefix "-l" && {
-			procd_append_param command "-L" "$handler"
-		}
+		local len
+		config_get len "$cfg" lua_prefix_LENGTH
+
+		if [ -n "$len" ]; then
+			config_list_foreach "$cfg" lua_prefix append_lua_prefix
+		else
+			config_get prefix "$cfg" lua_prefix
+			config_get handler "$cfg" lua_handler
+			append_lua_prefix "$prefix=$handler"
+		fi
 	}
 	[ -f /usr/lib/uhttpd_ubus.so ] && {
 		append_arg "$cfg" ubus_prefix "-u"