CC Protect Startup

local FILE_TO_PROTECT  = shell.resolve ("/startup")
local old_fsOpen       = _G["fs"]["open"]
local old_fsDelete     = _G["fs"]["delete"]
local old_fsIsReadOnly = _G["fs"]["isReadOnly"]

-- Override of fs.open.
_G["fs"]["open"] = function (path, mode)
    path = shell.resolve (path)
    mode = string.lower (mode)

    if path == FILE_TO_PROTECT then
        return nil
    end

    return old_fsOpen (path, mode)
end

-- Override of fs.delete.
_G["fs"]["delete"] = function (path)
    path = shell.resolve (path)

    if path == FILE_TO_PROTECT then
        -- Mimick error.
        return shell.run ("delete", "/rom/")
    end

    return old_fsDelete (path)
end

-- Override of fs.isReadOnly.
_G["fs"]["isReadOnly"] = function (path)
    path = shell.resolve (path)

    if path == FILE_TO_PROTECT then
        return true
    end

    return old_fsIsReadOnly (path)
end