1 files changed, 86 insertions, 0 deletions
diff --git a/src/plugins/factoids/sandbox.lua b/src/plugins/factoids/sandbox.lua
new file mode 100644
index 0000000..3fc74cd
--- /dev/null
+++ b/src/plugins/factoids/sandbox.lua
@@ -0,0 +1,86 @@
+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
+
+local sandbox_env = {
+  print = send,
+  println = sendln,
+  eval = nil,
+  args = args,
+  input = input,
+  user = user,
+  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
+
+sandbox_env.eval = eval
+
+-- Check if the factoid timed out
+function checktime(event, line)
+  if os.time() - time >= timeout then
+    error("Timed out after " .. timeout .. " seconds", 0)
+  else
+    -- Limit the cpu usage of factoids
+    sleep(1)
+  end
+end
+
+local f, e = load(factoid, nil, nil, sandbox_env)
+
+-- Add timeout hook
+time = os.time()
+timeout = 30
+debug.sethook(checktime, "l")
+
+if f then
+  f()
+else
+  error(e)
+end