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function send(text)
local text = tostring(text)
local len = #output
if len < 1 then
output = { text }
else
output[len] = output[len] .. text
end
end
function sendln(text)
send(text)
table.insert(output, "")
end
function trim(s)
local from = s:match"^%s*()"
return from > #s and "" or s:match(".*%S", from)
end
trimmedInput = trim(input)
if trimmedInput == "" then
ioru = user
else
ioru = trimmedInput
end
local sandbox_env = {
print = send,
println = sendln,
trim = trim,
eval = nil,
sleep = nil,
args = args,
input = input,
user = user,
ioru = ioru,
channel = channel,
request = download,
string = string,
math = math,
table = table,
pairs = pairs,
ipairs = ipairs,
next = next,
select = select,
unpack = unpack,
tostring = tostring,
tonumber = tonumber,
type = type,
assert = assert,
error = error,
pcall = pcall,
xpcall = xpcall,
_VERSION = _VERSION
}
sandbox_env.os = {
clock = os.clock,
time = os.time,
difftime = os.difftime
}
sandbox_env.string.rep = nil
sandbox_env.string.dump = nil
sandbox_env.math.randomseed = nil
-- Temporary evaluation function
function eval(code)
local c, e = load(code, nil, nil, sandbox_env)
if c then
return c()
else
error(e)
end
end
-- Only sleeps for 1 second at a time
-- This ensures that the timeout check can still run
function safesleep(dur)
while dur > 1000 do
dur = dur - 1000
sleep(1000)
end
sleep(dur)
end
sandbox_env.eval = eval
sandbox_env.sleep = safesleep
-- Check if the factoid timed out
function checktime()
if os.time() - time >= timeout then
error("Timed out after " .. timeout .. " seconds", 0)
else
-- Limit the cpu usage of factoids
sleep(1)
end
end
-- Check if the factoid uses too much memory
function checkmem()
if collectgarbage("count") > maxmem then
error("Factoid used over " .. maxmem .. " kbyte of ram")
end
end
local f, e = load(factoid, nil, nil, sandbox_env)
-- Add timeout hook
time = os.time()
-- The timeout is defined in seconds
timeout = 30
debug.sethook(checktime, "l")
-- Add memory check hook
-- The max memory is defined in kilobytes
maxmem = 1000
debug.sethook(checkmem, "l")
if f then
f()
else
error(e)
end
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