local target = ...
if not target then
  print("Usage: "..fs.getName(shell.getRunningProgram()).." [target]")
  return
end

local lastDumped = nil
getfenv(parallel.waitForAny).os = setmetatable({pullEventRaw = function(...)
  local i = 2
  while true do
    local success, result = pcall(function()
      local fn = setfenv(i, getfenv(i))
      return string.dump(fn)
    end)
    i = i + 1
    if success then
      lastDumped = result
    else
      if result:find("invalid level") then
        break
      end
    end
  end
  getfenv(parallel.waitForAny).os = nil
  return coroutine.yield(...)
end}, {__index = os})

os.queueEvent("fake-event")
os.pullEvent("fake-event")

getfenv(parallel.waitForAny).os = nil

if lastDumped then
  print("Writing bios file...")

  local handle = fs.open(target, "wb")
  for i=1,lastDumped:len() do
    handle.write(lastDumped:byte(i))
  end
  handle.close()

  print("Successfully dumped (hopefully)!")
else
  print("Dump failed")
end