301 lines
9.8 KiB
Lua
301 lines
9.8 KiB
Lua
--
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-- SSCSM: Server-Sent Client-Side Mods proof-of-concept
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--
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-- Copyright © 2019 by luk3yx
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--
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-- For debugging, this can be a global variable.
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local sscsm = {}
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-- Load the Env class
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-- Mostly copied from https://stackoverflow.com/a/26367080
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-- Don't copy metatables
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local function copy(obj, s)
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if s and s[obj] ~= nil then return s[obj] end
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if type(obj) ~= 'table' then return obj end
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s = s or {}
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local res = {}
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s[obj] = res
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for k, v in pairs(obj) do res[copy(k, s)] = copy(v, s) end
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return res
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end
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-- Safe functions
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local Env = {}
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local safe_funcs = {}
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-- No getmetatable()
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if rawget(_G, 'getmetatable') then
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safe_funcs[getmetatable] = function() end
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end
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-- Get the current value of string.rep in case other CSMs decide to break
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do
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local rep = string.rep
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safe_funcs[string.rep] = function(str, n)
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if #str * n > 1048576 then
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error('string.rep: string length overflow', 2)
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end
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return rep(str, n)
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end
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local show_formspec = minetest.show_formspec
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safe_funcs[show_formspec] = function(formname, ...)
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if type(formname) == 'string' and formname:sub(1, 6) ~= 'sscsm:' then
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return show_formspec(formname, ...)
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end
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end
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local after = minetest.after
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safe_funcs[after] = function(n, ...)
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if type(n) == 'number' then return after(n, pcall, ...) end
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end
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local on_fs_input = minetest.register_on_formspec_input
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safe_funcs[on_fs_input] = function(func)
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on_fs_input(function(formname, fields)
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if formname:sub(1, 6) ~= 'sscsm:' then
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pcall(func, formname, copy(fields))
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end
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end)
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end
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local deserialize = minetest.deserialize
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safe_funcs[deserialize] = function(str)
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return deserialize(str, true)
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end
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local wrap = function(n)
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local orig = minetest[n] or minetest[n .. 's']
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if type(orig) == 'function' then
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return function(func)
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orig(function(...)
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local r = {pcall(func, ...)}
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if r[1] then
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table.remove(r, 1)
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return (table.unpack or unpack)(r)
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else
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minetest.log('error', '[SSCSM] ' .. tostring(r[2]))
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end
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end)
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end
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end
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end
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for _, k in ipairs({'register_globalstep', 'register_on_death',
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'register_on_hp_modification', 'register_on_damage_taken',
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'register_on_dignode', 'register_on_punchnode',
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'register_on_placenode', 'register_on_item_use',
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'register_on_modchannel_message', 'register_on_modchannel_signal',
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'register_on_inventory_open', 'register_on_sending_chat_message',
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'register_on_receiving_chat_message'}) do
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safe_funcs[minetest[k]] = wrap(k)
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end
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end
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-- Environment
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function Env.new_empty()
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local self = {_raw = {}, _seen = copy(safe_funcs)}
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self._raw['_G'] = self._raw
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return setmetatable(self, {__index = Env}) or self
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end
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function Env:get(k) return self._raw[self._seen[k] or k] end
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function Env:set(k, v) self._raw[copy(k, self._seen)] = copy(v, self._seen) end
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function Env:set_copy(k, v)
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self:set(k, v)
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self._seen[k] = nil
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self._seen[v] = nil
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end
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function Env:add_globals(...)
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for i = 1, select('#', ...) do
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local var = select(i, ...)
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self:set(var, _G[var])
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end
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end
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function Env:update(data) for k, v in pairs(data) do self:set(k, v) end end
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function Env:del(k)
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if self._seen[k] then
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self._raw[self._seen[k]] = nil
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self._seen[k] = nil
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end
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self._raw[k] = nil
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end
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function Env:copy()
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local new = {_seen = copy(safe_funcs)}
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new._raw = copy(self._raw, new._seen)
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return setmetatable(new, {__index = Env}) or new
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end
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-- Load code into a callable function.
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function Env:loadstring(code, file)
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if code:byte(1) == 27 then return nil, 'Invalid code!' end
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local f, msg = loadstring(code, ('=%q'):format(file))
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if not f then return nil, msg end
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setfenv(f, self._raw)
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return function(...)
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local good, msg = pcall(f, ...)
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if good then
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return msg
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else
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minetest.log('error', '[SSCSM] ' .. tostring(msg))
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end
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end
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end
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function Env:exec(code, file)
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local f, msg = self:loadstring(code, file)
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if not f then
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minetest.log('error', '[SSCSM] Syntax error: ' .. tostring(msg))
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return false
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end
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f()
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return true
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end
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-- Create the "base" environment
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local base_env = Env:new_empty()
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function Env.new() return base_env:copy() end
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-- Clone everything
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base_env:add_globals('assert', 'dump', 'dump2', 'error', 'ipairs', 'math',
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'next', 'pairs', 'pcall', 'select', 'setmetatable', 'string', 'table',
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'tonumber', 'tostring', 'type', 'vector', 'xpcall', '_VERSION')
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base_env:set_copy('os', {clock = os.clock, difftime = os.difftime,
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time = os.time})
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-- Create a slightly locked down "minetest" table
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do
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local t = {}
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for _, k in ipairs({"add_particle", "add_particlespawner", "after",
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"camera", "clear_out_chat_queue", "colorize", "compress", "debug",
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"decode_base64", "decompress", "delete_particlespawner",
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"deserialize", "disconnect", "display_chat_message",
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"encode_base64", "explode_scrollbar_event", "explode_table_event",
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"explode_textlist_event", "find_node_near", "find_nodes_in_area",
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"find_nodes_in_area_under_air", "find_nodes_with_meta",
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"formspec_escape", "get_background_escape_sequence",
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"get_color_escape_sequence", "get_day_count", "get_item_def",
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"get_language", "get_meta", "get_node_def", "get_node_level",
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"get_node_light", "get_node_max_level", "get_node_or_nil",
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"get_player_names", "get_privilege_list", "get_server_info",
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"get_timeofday", "get_translator", "get_us_time", "get_version",
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"get_wielded_item", "gettext", "is_nan", "is_yes", "line_of_sight",
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"localplayer", "log", "mod_channel_join", "parse_json",
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"pointed_thing_to_face_pos", "pos_to_string", "privs_to_string",
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"raycast", "register_globalstep", "register_on_damage_taken",
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"register_on_death", "register_on_dignode",
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"register_on_formspec_input", "register_on_hp_modification",
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"register_on_inventory_open", "register_on_item_use",
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"register_on_modchannel_message", "register_on_modchannel_signal",
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"register_on_placenode", "register_on_punchnode",
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"register_on_receiving_chat_message",
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"register_on_sending_chat_message", "rgba",
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"run_server_chatcommand", "send_chat_message", "send_respawn",
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"serialize", "sha1", "show_formspec", "sound_play", "sound_stop",
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"string_to_area", "string_to_pos", "string_to_privs",
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"strip_background_colors", "strip_colors",
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"strip_foreground_colors", "translate", "ui", "wrap_text",
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"write_json"}) do
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local func = minetest[k]
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t[k] = safe_funcs[func] or func
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end
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base_env:set_copy('minetest', t)
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end
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-- Add table.unpack
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if not table.unpack then
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base_env._raw.table.unpack = unpack
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end
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-- Make sure copy() worked correctly
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assert(base_env._raw.minetest.register_on_sending_chat_message ~=
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minetest.register_on_sending_chat_message, 'Error in copy()!')
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-- SSCSM functions
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-- When calling these from an SSCSM, make sure they exist first.
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local mod_channel
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local loaded_sscsms = {}
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base_env:set('join_mod_channel', function()
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if not mod_channel then
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mod_channel = minetest.mod_channel_join('sscsm:exec_pipe')
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end
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end)
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base_env:set('leave_mod_channel', function()
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if mod_channel then
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mod_channel:leave()
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mod_channel = false
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end
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end)
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-- Allow other CSMs to access the new Environment type
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sscsm.Env = Env
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-- exec() code sent by the server.
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minetest.register_on_modchannel_message(function(channel_name, sender, message)
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if channel_name ~= 'sscsm:exec_pipe' or (sender and sender ~= '') then
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return
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end
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-- The first character is currently a version code, currently 0.
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-- Do not change unless absolutely necessary.
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local version = message:sub(1, 1)
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local name, code
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if version == '0' then
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local s, e = message:find('\n')
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if not s or not e then return end
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local target = message:sub(2, s - 1)
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if target ~= minetest.localplayer:get_name() then return end
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message = message:sub(e + 1)
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local s, e = message:find('\n')
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if not s or not e then return end
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name = message:sub(1, s - 1)
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code = message:sub(e + 1)
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else
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return
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end
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-- Create the environment
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if not sscsm.env then sscsm.env = Env:new() end
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-- Don't load the same SSCSM twice
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if not loaded_sscsms[name] then
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minetest.log('action', '[SSCSM] Loading ' .. name)
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loaded_sscsms[name] = true
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sscsm.env:exec(code, name)
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end
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end)
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-- Send "0" when the "sscsm:exec_pipe" channel is first joined.
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local sent_request = false
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minetest.register_on_modchannel_signal(function(channel_name, signal)
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if sent_request or channel_name ~= 'sscsm:exec_pipe' then
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return
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end
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if signal == 0 then
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base_env._raw.minetest.localplayer = minetest.localplayer
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base_env._raw.minetest.camera = minetest.camera
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mod_channel:send_all('0')
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sent_request = true
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elseif signal == 1 then
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mod_channel:leave()
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mod_channel = nil
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end
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end)
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local function attempt_to_join_mod_channel()
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-- Wait for minetest.localplayer to become available.
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if not minetest.localplayer then
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minetest.after(0.05, attempt_to_join_mod_channel)
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return
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end
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-- Join the mod channel
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mod_channel = minetest.mod_channel_join('sscsm:exec_pipe')
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end
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minetest.after(0, attempt_to_join_mod_channel)
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