aboutsummaryrefslogtreecommitdiff
path: root/advtrains/advtrains_luaautomation/environment.lua
blob: c7b801cb0ecc332e97d1b26e99a5a880131b0a4f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
-------------
-- lua sandboxed environment

-- function to cross out functions and userdata.
-- modified from dump()
function atlatc.remove_invalid_data(o, nested)
	if o==nil then return nil end
	local valid_dt={["nil"]=true, boolean=true, number=true, string=true}
	if type(o) ~= "table" then
		--check valid data type
		if not valid_dt[type(o)] then
			return nil
		end
		return o
	end
	-- Contains table -> true/nil of currently nested tables
	nested = nested or {}
	if nested[o] then
		return nil
	end
	nested[o] = true
	for k, v in pairs(o) do
		v = atlatc.remove_invalid_data(v, nested)
	end
	nested[o] = nil
	return o
end
function atlatc.replace_function_envs(o, fenv, nested)
	if o==nil then return nil end
	local valid_dt={["nil"]=true, boolean=true, number=true, string=true}
	if type(o) ~= "table" then
		--check valid data type
		if type(o)=="function" then
			setfenv(o, fenv)
		end
		return o
	end
	-- Contains table -> true/nil of currently nested tables
	nested = nested or {}
	if nested[o] then
		return nil
	end
	nested[o] = true
	for k, v in pairs(o) do
		v = atlatc.replace_function_envs(v, fenv, nested)
	end
	nested[o] = nil
	return o
end


local env_proto={
	load = function(self, envname, data)
		self.name=envname
		self.sdata=data.sdata and atlatc.remove_invalid_data(data.sdata) or {}
		self.fdata={}
		self.init_code=data.init_code or ""
		self.step_code=data.step_code or ""
	end,
	save = function(self)
		-- throw any function values out of the sdata table
		self.sdata = atlatc.remove_invalid_data(self.sdata)
		return {sdata = self.sdata, init_code=self.init_code, step_code=self.step_code}
	end,
}

--Environment
--Code modified from mesecons_luacontroller (credit goes to Jeija and mesecons contributors)

local safe_globals = {
	"assert", "error", "ipairs", "next", "pairs", "select",
	"tonumber", "tostring", "type", "unpack", "_VERSION"
}

--print is actually minetest.chat_send_all()
--using advtrains.print_concat_table because it's cool
local function safe_print(t, ...)
	local str=advtrains.print_concat_table({t, ...})
	minetest.log("action", "[atlatc] "..str)
	minetest.chat_send_all(str)
end

local function safe_date()
	return(os.date("*t",os.time()))
end

-- string.rep(str, n) with a high value for n can be used to DoS
-- the server. Therefore, limit max. length of generated string.
local function safe_string_rep(str, n)
	if #str * n > 2000 then
		debug.sethook() -- Clear hook
		error("string.rep: string length overflow", 2)
	end

	return string.rep(str, n)
end

-- string.find with a pattern can be used to DoS the server.
-- Therefore, limit string.find to patternless matching.
local function safe_string_find(...)
	if (select(4, ...)) ~= true then
		debug.sethook() -- Clear hook
		error("string.find: 'plain' (fourth parameter) must always be true for security reasons.")
	end

	return string.find(...)
end

local mp=minetest.get_modpath("advtrains_luaautomation")
local p_api_getstate, p_api_setstate = dofile(mp.."/passive.lua")

local static_env = {
	--core LUA functions
	print = safe_print,
	string = {
		byte = string.byte,
		char = string.char,
		format = string.format,
		len = string.len,
		lower = string.lower,
		upper = string.upper,
		rep = safe_string_rep,
		reverse = string.reverse,
		sub = string.sub,
		find = safe_string_find,
	},
	math = {
		abs = math.abs,
		acos = math.acos,
		asin = math.asin,
		atan = math.atan,
		atan2 = math.atan2,
		ceil = math.ceil,
		cos = math.cos,
		cosh = math.cosh,
		deg = math.deg,
		exp = math.exp,
		floor = math.floor,
		fmod = math.fmod,
		frexp = math.frexp,
		huge = math.huge,
		ldexp = math.ldexp,
		log = math.log,
		log10 = math.log10,
		max = math.max,
		min = math.min,
		modf = math.modf,
		pi = math.pi,
		pow = math.pow,
		rad = math.rad,
		random = math.random,
		sin = math.sin,
		sinh = math.sinh,
		sqrt = math.sqrt,
		tan = math.tan,
		tanh = math.tanh,
	},
	table = {
		concat = table.concat,
		insert = table.insert,
		maxn = table.maxn,
		remove = table.remove,
		sort = table.sort,
	},
	os = {
		clock = os.clock,
		difftime = os.difftime,
		time = os.time,
		date = safe_date,
	},
	POS = function(x,y,z) return {x=x, y=y, z=z} end,
	getstate = p_api_getstate,
	setstate = p_api_setstate,
	--interrupts are handled per node, position unknown.
	--however external interrupts can be set here.
	interrupt_pos = function(pos, imesg)
		if not type(pos)=="table" or not pos.x or not pos.y or not pos.z then
			debug.sethook()
			error("Invalid position supplied to interrupt_pos")
		end
		atlatc.interrupt.add(0, pos, {type="ext_int", ext_int=true, message=imesg})
	end,
}

for _, name in pairs(safe_globals) do
	static_env[name] = _G[name]
end


--The environment all code calls get is a table that has set static_env as metatable.
--In general, every variable is local to a single code chunk, but kept persistent over code re-runs. Data is also saved, but functions and userdata and circular references are removed
--Init code and step code's environments are not saved
-- S - Table that can contain any save data global to the environment. Will be saved statically. Can't contain functions or userdata or circular references.
-- F - Table global to the environment, can contain volatile data that is deleted when server quits.
--     The init code should populate this table with functions and other definitions.

-- returns: true, fenv if successful; nil, error if error 
function env_proto:execute_code(fenv, code, evtdata, customfct)
	local metatbl ={
		__index = function(t, i)
			if i=="S" then
				return self.sdata
			elseif i=="F" then
				return self.fdata
			elseif i=="event" then
				return evtdata
			elseif customfct and customfct[i] then
				return customfct[i]
			end
			return static_env[i]
		end,
		__newindex = function(t, i, v)
			if i=="S" or i=="F" or i=="event" or (customfct and customfct[i]) or static_env[i] then
				debug.sethook()
				error("Trying to overwrite environment contents")
			end
			rawset(t,i,v)
		end,
	}
	setmetatable(fenv, metatbl)
	local fun, err=loadstring(code)
	if not fun then
		return false, err
	end
	--set function environment for all functions residing in F, so they get the right variables. Else it's a huge mess...
	atlatc.replace_function_envs(self.fdata, fenv)
	
	setfenv(fun, fenv)
	local succ, data = pcall(fun)
	if succ then
		data=fenv
	end
	return succ, data
end

function env_proto:run_initcode()
	if self.init_code and self.init_code~="" then
		self.fdata = {}
		atprint("[atlatc]Running initialization code for environment '"..self.name.."'")
		local succ, err = self:execute_code({}, self.init_code, {type="init", init=true})
		if not succ then
			self.init_err=err
		end
	end
end
function env_proto:run_stepcode()
	if self.step_code and self.step_code~="" then
		local succ, err = self:execute_code({}, self.step_code, nil, {})
		if not succ then
			--TODO
		end
	end
end

--- class interface

function atlatc.env_new(name)
	local newenv={
		name=name,
		init_code="",
		step_code="",
		sdata={}
	}
	setmetatable(newenv, {__index=env_proto})
	return newenv
end
function atlatc.env_load(name, data)
	local newenv={}
	setmetatable(newenv, {__index=env_proto})
	newenv:load(name, data)
	return newenv
end

function atlatc.run_initcode()
	for envname, env in pairs(atlatc.envs) do
		env:run_initcode()
	end
end
function atlatc.run_stepcode()
	for envname, env in pairs(atlatc.envs) do
		env:run_stepcode()
	end
end