advtrains/advtrains_luaautomation/environment.lua

276 lines
7.1 KiB
Lua

-------------
-- 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
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.
-- Note: Disabled security since there are enough security leaks and this would be unneccessary anyway to DoS the server
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.
local proxy_env={}
--proxy_env gets a new metatable in every run, but is the shared environment of all functions ever defined.
-- returns: true, fenv if successful; nil, error if error
function env_proto:execute_code(localenv, 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]
elseif localenv and localenv[i] then
return localenv[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
localenv[i]=v
end,
}
setmetatable(proxy_env, metatbl)
local fun, err=loadstring(code)
if not fun then
return false, err
end
setfenv(fun, proxy_env)
local succ, data = pcall(fun)
if succ then
data=localenv
end
return succ, data
end
function env_proto:run_initcode()
if self.init_code and self.init_code~="" then
local old_fdata=self.fdata
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
atwarn("[atlatc]Executing InitCode for '"..self.name.."' failed:"..err)
self.init_err=err
if old_fdata then
self.fdata=old_fdata
atwarn("[atlatc]The 'F' table has been restored to the previous state.")
end
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