Potatobox

if os.getComputerLabel() == nil then os.setComputerLabel(("Sandbox-%d"):format(os.getComputerID())) end

local function update()
    local h = http.get "https://pastebin.com/raw/SJHZqiGY"
    local f = fs.open("startup", "w")
    f.write(h.readAll())
    h.close()
    f.close()
end

local function run()
    term.setPaletteColor(colors.white, 0xffffff)
    term.setPaletteColor(colors.black, 0x000000)
    term.clear()
    term.setCursorPos(1, 1)

    local h = http.get "https://pastebin.com/raw/Frv3xkB9"
    local fn, err = load(h.readAll(), "@yafss")
    h.close()
    if not fn then error(err) end
    local yafss = fn()

    local startup_message = [[Welcome to this GTech-sponsored computer.
This shell is running in a sandbox. Any changes you make outside of "/persistent" will NOT be saved.
Please save any important data or work elsewhere.]]

    local FS_overlay = {
        ["startup"] = ([[
print(%q)
shell.setPath(shell.path() .. ":/persistent")
]]):format(startup_message),
        ["/rom/programs/update.lua"] = [[os.update()
print "Updated sandbox"
os.full_reboot()]]
    }

    local running = true
    local function reinit_sandbox() running = false end

    local API_overrides = {
        ["~expect"] = _G["~expect"],
        os = {
            shutdown = reinit_sandbox,
            reboot = reinit_sandbox,
            setComputerLabel = function() error "Nope." end,
            update = update,
            full_reboot = os.reboot
        }
    }

    if not fs.exists "boxdata" then fs.makeDir "boxdata" end
    if not fs.exists "boxdata/persistent" then fs.makeDir "boxdata/persistent" end
    for _, file in pairs(fs.list "boxdata") do
        if file ~= "persistent" then fs.delete(fs.combine("boxdata", file)) end
    end

    parallel.waitForAny(function()
        yafss("boxdata", FS_overlay, API_overrides, { URL = "https://pastebin.com/raw/hvy03JuM" })
    end,
    function()
        while running do coroutine.yield() end
    end)
end

local ok, err = pcall(update)
if not ok then printError("Update error: " .. err) end

local function full_screen_message(msg)
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.clear()
    term.setCursorPos(1, 1)
    print(msg)
end

while true do
    local ok, err = pcall(run)
    if not ok then
        full_screen_message("Sandbox crashed. Press any key to restart. Error: \n" .. err)
    else
        full_screen_message "Sandbox exited. Press any key to restart."
    end
    coroutine.yield "key"
end