Add client-side SSCSM support.

builtin/client/init.lua

@@ -9,3 +9,4 @@ dofile(commonpath .. "chatcommands.lua")
 dofile(clientpath .. "chatcommands.lua")
 dofile(commonpath .. "vector.lua")
 dofile(clientpath .. "death_formspec.lua")
+dofile(clientpath .. "sscsm.lua")

builtin/client/sscsm.lua

@@ -0,0 +1,312 @@
+--
+-- SSCSM: Server-Sent Client-Side Mods
+--
+-- Copyright © 2019-2021 by luk3yx
+-- Copyright © 2020-2021 MultiCraft Development Team
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU Lesser General Public License as published by
+-- the Free Software Foundation; either version 3.0 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Lesser General Public License for more details.
+--
+-- You should have received a copy of the GNU Lesser General Public License
+-- along with this program; if not, write to the Free Software Foundation,
+-- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+--
+
+-- For debugging, this can be a global variable.
+local sscsm = {}
+
+-- Load the Env class
+-- Mostly copied from https://stackoverflow.com/a/26367080
+-- Don't copy metatables
+local function copy(obj, s)
+	if s and s[obj] ~= nil then return s[obj] end
+	if type(obj) ~= "table" then return obj end
+	s = s or {}
+	local res = {}
+	s[obj] = res
+	for k, v in pairs(obj) do res[copy(k, s)] = copy(v, s) end
+	return res
+end
+
+-- Safe functions
+local Env = {}
+local safe_funcs = {}
+
+-- No getmetatable()
+if rawget(_G, "getmetatable") then
+	safe_funcs[getmetatable] = function() end
+end
+
+-- Get the current value of string.rep in case other CSMs decide to break
+do
+	local rep = string.rep
+	safe_funcs[string.rep] = function(str, n)
+		if #str * n > 1048576 then
+			error("string.rep: string length overflow", 2)
+		end
+		return rep(str, n)
+	end
+
+	local show_formspec = minetest.show_formspec
+	safe_funcs[show_formspec] = function(formname, ...)
+		if type(formname) == "string" then
+			return show_formspec("sscsm:_" .. formname, ...)
+		end
+	end
+
+	local after = minetest.after
+	safe_funcs[after] = function(n, ...)
+		if type(n) == "number" then return after(n, pcall, ...) end
+	end
+
+	local on_fs_input = minetest.register_on_formspec_input
+	safe_funcs[on_fs_input] = function(func)
+		on_fs_input(function(formname, fields)
+			if formname:sub(1, 7) == "sscsm:_" then
+				pcall(func, formname:sub(8), copy(fields))
+			end
+		end)
+	end
+
+	local deserialize = minetest.deserialize
+	safe_funcs[deserialize] = function(str)
+		return deserialize(str, true)
+	end
+
+	local wrap = function(n)
+		local orig = minetest[n] or minetest[n .. "s"]
+		if type(orig) == "function" then
+			return function(func)
+				orig(function(...)
+					local r = {pcall(func, ...)}
+					if r[1] then
+						table.remove(r, 1)
+						return (table.unpack or unpack)(r)
+					else
+						minetest.log("error", "[SSCSM] " .. tostring(r[2]))
+					end
+				end)
+			end
+		end
+	end
+
+	for _, k in ipairs({"register_globalstep", "register_on_death",
+			"register_on_hp_modification", "register_on_damage_taken",
+			"register_on_dignode", "register_on_punchnode",
+			"register_on_placenode", "register_on_item_use",
+			"register_on_modchannel_message", "register_on_modchannel_signal",
+			"register_on_inventory_open", "register_on_sending_chat_message",
+			"register_on_receiving_chat_message"}) do
+		safe_funcs[minetest[k]] = wrap(k)
+	end
+end
+
+-- Environment
+function Env.new_empty()
+	local self = {_raw = {}, _seen = copy(safe_funcs)}
+	self._raw["_G"] = self._raw
+	return setmetatable(self, {__index = Env}) or self
+end
+function Env:get(k) return self._raw[self._seen[k] or k] end
+function Env:set(k, v) self._raw[copy(k, self._seen)] = copy(v, self._seen) end
+function Env:set_copy(k, v)
+	self:set(k, v)
+	self._seen[k] = nil
+	self._seen[v] = nil
+end
+function Env:add_globals(...)
+	for i = 1, select("#", ...) do
+		local var = select(i, ...)
+		self:set(var, _G[var])
+	end
+end
+function Env:update(data) for k, v in pairs(data) do self:set(k, v) end end
+function Env:del(k)
+	if self._seen[k] then
+		self._raw[self._seen[k]] = nil
+		self._seen[k] = nil
+	end
+	self._raw[k] = nil
+end
+
+function Env:copy()
+	local new = {_seen = copy(safe_funcs)}
+	new._raw = copy(self._raw, new._seen)
+	return setmetatable(new, {__index = Env}) or new
+end
+
+-- Load code into a callable function.
+function Env:loadstring(code, file)
+	if code:byte(1) == 27 then return nil, "Invalid code!" end
+	local f, msg = loadstring(code, ("=%q"):format(file))
+	if not f then return nil, msg end
+	setfenv(f, self._raw)
+	return function(...)
+		local good, msg = pcall(f, ...)
+		if good then
+			return msg
+		else
+			minetest.log("error", "[SSCSM] " .. tostring(msg))
+		end
+	end
+end
+
+function Env:exec(code, file)
+	local f, msg = self:loadstring(code, file)
+	if not f then
+		minetest.log("error", "[SSCSM] Syntax error: " .. tostring(msg))
+		return false
+	end
+	f()
+	return true
+end
+
+-- Create the "base" environment
+local base_env = Env:new_empty()
+function Env.new() return base_env:copy() end
+
+-- Clone everything
+base_env:add_globals("assert", "dump", "dump2", "error", "ipairs", "math",
+	"next", "pairs", "pcall", "select", "setmetatable", "string", "table",
+	"tonumber", "tostring", "type", "vector", "xpcall", "_VERSION", "utf8")
+
+base_env:set_copy("os", {clock = os.clock, difftime = os.difftime,
+	time = os.time})
+
+-- Create a slightly locked down "minetest" table
+do
+	local t = {}
+	for _, k in ipairs({"add_particle", "add_particlespawner", "after",
+			"camera", "clear_out_chat_queue", "colorize", "compress", "debug",
+			"decode_base64", "decompress", "delete_particlespawner",
+			"deserialize", "disconnect", "display_chat_message",
+			"encode_base64", "explode_scrollbar_event", "explode_table_event",
+			"explode_textlist_event", "find_node_near", "find_nodes_in_area",
+			"find_nodes_in_area_under_air", "find_nodes_with_meta",
+			"formspec_escape", "get_background_escape_sequence",
+			"get_color_escape_sequence", "get_day_count", "get_item_def",
+			"get_language", "get_meta", "get_node_def", "get_node_level",
+			"get_node_light", "get_node_max_level", "get_node_or_nil",
+			"get_player_names", "get_privilege_list", "get_server_info",
+			"get_timeofday", "get_translator", "get_us_time", "get_version",
+			"get_wielded_item", "gettext", "is_nan", "is_yes", "line_of_sight",
+			"localplayer", "log", "mod_channel_join", "parse_json",
+			"pointed_thing_to_face_pos", "pos_to_string", "privs_to_string",
+			"raycast", "register_globalstep", "register_on_damage_taken",
+			"register_on_death", "register_on_dignode",
+			"register_on_formspec_input", "register_on_hp_modification",
+			"register_on_inventory_open", "register_on_item_use",
+			"register_on_modchannel_message", "register_on_modchannel_signal",
+			"register_on_placenode", "register_on_punchnode",
+			"register_on_receiving_chat_message",
+			"register_on_sending_chat_message", "rgba",
+			"run_server_chatcommand", "send_chat_message", "send_respawn",
+			"serialize", "sha1", "show_formspec", "sound_play", "sound_stop",
+			"string_to_area", "string_to_pos", "string_to_privs",
+			"strip_background_colors", "strip_colors",
+			"strip_foreground_colors", "translate", "ui", "wrap_text",
+			"write_json"}) do
+		local func = minetest[k]
+		t[k] = safe_funcs[func] or func
+	end
+
+	base_env:set_copy("minetest", t)
+end
+
+-- Add table.unpack
+if not table.unpack then
+	base_env._raw.table.unpack = unpack
+end
+
+-- Make sure copy() worked correctly
+assert(base_env._raw.minetest.register_on_sending_chat_message ~=
+	minetest.register_on_sending_chat_message, "Error in copy()!")
+
+-- SSCSM functions
+-- When calling these from an SSCSM, make sure they exist first.
+local mod_channel
+local loaded_sscsms = {}
+base_env:set("join_mod_channel", function()
+	if not mod_channel then
+		mod_channel = minetest.mod_channel_join("sscsm:exec_pipe")
+	end
+end)
+
+base_env:set("leave_mod_channel", function()
+	if mod_channel then
+		mod_channel:leave()
+		mod_channel = nil
+	end
+end)
+
+-- exec() code sent by the server.
+minetest.register_on_modchannel_message(function(channel_name, sender, message)
+	if channel_name ~= "sscsm:exec_pipe" or (sender and sender ~= "") then
+		return
+	end
+
+	-- The first character is currently a version code, currently 0.
+	-- Do not change unless absolutely necessary.
+	local version = message:sub(1, 1)
+	local name, code
+	if version == "0" then
+		local s, e = message:find("\n")
+		if not s or not e then return end
+		local target = message:sub(2, s - 1)
+		if target ~= minetest.localplayer:get_name() then return end
+		message = message:sub(e + 1)
+		s, e = message:find("\n")
+		if not s or not e then return end
+		name = message:sub(1, s - 1)
+		code = message:sub(e + 1)
+	else
+		return
+	end
+
+	-- Create the environment
+	if not sscsm.env then sscsm.env = Env:new() end
+
+	-- Don't load the same SSCSM twice
+	if not loaded_sscsms[name] then
+		minetest.log("action", "[SSCSM] Loading " .. name)
+		loaded_sscsms[name] = true
+		sscsm.env:exec(code, name)
+	end
+end)
+
+-- Send "0" when the "sscsm:exec_pipe" channel is first joined.
+local sent_request = false
+minetest.register_on_modchannel_signal(function(channel_name, signal)
+	if sent_request or channel_name ~= "sscsm:exec_pipe" then
+		return
+	end
+
+	if signal == 0 then
+		base_env._raw.minetest.localplayer = minetest.localplayer
+		base_env._raw.minetest.camera = minetest.camera
+		mod_channel:send_all("0")
+		sent_request = true
+	elseif signal == 1 then
+		mod_channel:leave()
+		mod_channel = nil
+	end
+end)
+
+local function attempt_to_join_mod_channel()
+	-- Wait for minetest.localplayer to become available.
+	if not minetest.localplayer then
+		minetest.after(0.05, attempt_to_join_mod_channel)
+		return
+	end
+
+	-- Join the mod channel
+	mod_channel = minetest.mod_channel_join("sscsm:exec_pipe")
+end
+minetest.after(0, attempt_to_join_mod_channel)

builtin/game/sscsm/client.lua

@@ -340,4 +340,4 @@ end)
 
 if not core.global_exists("utf8") or not utf8.lower then
 	utf8 = string
-end
+end

builtin/settingtypes.txt

@@ -975,7 +975,7 @@ enable_remote_media_server (Connect to external media server) bool true
 
 #    Enable Lua modding support on client.
 #    This support is experimental and API can change.
-enable_client_modding (Client modding) bool false
+enable_client_modding (Client modding) bool true
 
 #    URL to the server list displayed in the Multiplayer Tab.
 serverlist_url (Serverlist URL) string servers.minetest.net

multicraft.conf.example

@@ -1162,7 +1162,7 @@
 #    Enable Lua modding support on client.
 #    This support is experimental and API can change.
 #    type: bool
-# enable_client_modding = false
+# enable_client_modding = true
 
 #    URL to the server list displayed in the Multiplayer Tab.
 #    type: string

src/defaultsettings.cpp

@@ -59,7 +59,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("curl_file_download_timeout", "300000");
 	settings->setDefault("curl_verify_cert", "true");
 	settings->setDefault("enable_remote_media_server", "true");
-	settings->setDefault("enable_client_modding", "false");
+	settings->setDefault("enable_client_modding", "true");
 	settings->setDefault("max_out_chat_queue_size", "20");
 	settings->setDefault("pause_on_lost_focus", "false");
 	settings->setDefault("enable_register_confirmation", "true");