[ComputerCraft] GreaseMonkey Virus Cleaner

-- This will remove a nasty virus from the computer and put it back in shape.
-- URL to virus: http://www.computercraft.info/forums2/index.php?/topic/1102-a-decent-evalquine-resident-virus/
-- Pastebin: A51AN5xC

-- Run the following code on the infected machine:
-- ' /rom/programs/http/pastebin.lua run hnF94pw2 '

local infectedFiles = 0
local cleanFiles = 0

if (fs.exists("SafeDisk.lua")) then
    fs.delete("SafeDisk.lua")
end

local FileList = fs.list("") -- Table with all the files and directories available
for _, file in ipairs(FileList) do
    local reader = fs.open(file, "r") -- Try to open the file, errors if directory
    if reader then -- Is a file
        local content = reader.readAll() -- Read contents from file
        local isInfected = string.find(content, "xpayload" ) -- Checks if the file is infected

        reader.close()
        if isInfected then
            fs.delete(file)
            infectedFiles = infectedFiles + 1
        else
            cleanFiles = cleanFiles + 1
        end
    end
end

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

if (fs.exists("SafeDisk.lua")) then
    fs.delete("SafeDisk.lua")
end

local h = fs.open("SafeDisk.lua", "w")
h.write('local filePath = "/disk/startup"\n')
h.write('if not fs.exists(filePath) then filePath = "/disk/startup.lua" end\n')
h.write('if fs.exists(filePath) then\n')
h.write('   local reader = fs.open(filePath, "r") if not reader then return end -- Abort if it isnt a file\n')
h.write('   local content = reader.readAll() if not content then return end -- Abort if no content\n')
h.write('   local isInfected = string.find(content, "xpayload" ) -- Checks if the file is infected\n')
h.write('   if isInfected then\n')
h.write('       fs.delete(filePath)\n')
h.write('       print("Attempted to clean infected disk!")\n')
h.write('   else\n')
h.write('       shell.run(filePath)\n')
h.write('   end\n')
h.write('end\n')
h.close()

if (fs.exists("startup")) then
    fs.delete("startup")
end

h = fs.open("startup", "w")
-- Prints the log output at reboot
h.write("print(\"Cleaned up '"..infectedFiles.."' files from the system!\")")
h.write("print(\"A total of '"..cleanFiles.."' clean files where found!\")")
h.write('print("Safe disk boot installed!")')

-- Installs the SafeDisk software. Lets you reboot up safely.
h.write('h = fs.open("startup", "w")')
h.write("h.write('shell.run(\"SafeDisk.lua\") -- Runs disk IF it isnt this virus.')")
h.write("h.close()")
h.close()

os.reboot() -- Takes a reboot real fast, as the virus will install itself after a second.