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>

2 files changed, 29 insertions, 8 deletions

diff --git a/package/network/services/uhttpd/files/uhttpd.config b/package/network/services/uhttpd/files/uhttpd.config
index a7d769e188..a3deb9cf04 100644
--- a/package/network/services/uhttpd/files/uhttpd.config
+++ b/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
diff --git a/package/network/services/uhttpd/files/uhttpd.init b/package/network/services/uhttpd/files/uhttpd.init
index 47270bcc15..dc496b3e28 100755
--- a/package/network/services/uhttpd/files/uhttpd.init
+++ b/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"