CC Sandbox

-- Original by http://www.computercraft.info/forums2/index.php?/user/10136-engineer/

local args = { ... }

if fs.exists( args[1] ) then
        local f = fs.open( args[1], "r" )
        local content = f.readAll()
        f.close()

        local func, err = loadstring( content, args[1] )
        if not func then error( "Cannot propely sandbox this file: ".. err, 0 ) end

        local tArgs = {}
        for k, v in pairs( args ) do
                if k ~= 1 then
                        tArgs[#tArgs + 1] = v
                end
        end

        setfenv( func, setmetatable( {}, { __index = _G; __newindex = function( t, k, v ) printError( "Program is accessing global variables.", 0 ) end } ))
        func( unpack(tArgs) )
else
        printError( "Cannot sandbox a non-existing file!", 0 )
end