From: Christopher Dicely <cmdicely@...>
Date: 2008-04-21T01:53:03+09:00
Subject: Re: Executing code in a variable

On Sun, Apr 20, 2008 at 7:31 AM, Robert Dober <robert.dober@gmail.com> wrote:
> On Sun, Apr 20, 2008 at 3:53 PM, David A. Black <dblack@rubypal.com> wrote:
>
>  As David I am not sure that instance_eval is safer than eval. As the
>  following example shows a save eval can be done by deleting all
>  dangerous methods before evalling:
>
>  module Kernel
>   class << self
>     methods.each do |m|
>       next if /^__/ === m
>       Object::send :remove_method, m
>     end
>   end
>   instance_methods.each do |m|
>     next if /^__/ === m
>     Object::send :remove_method, m
>     remove_method m
>   end
>  end
>
>
>  eval %<system "ls -l">
>
>  Now this might not often be very useful though as we do not have a
>  sandbox or to put it better, it is much work to get out
>  of the sandbox again as we have to redefine all methods again (well I
>  did not safe them in the first place here). Furthermore my sandbox is
>  empty!!!
>
>  Is there an easy way to do this?

Well, we could use _why's Freaky Freaky Sandbox:
http://code.whytheluckystiff.net/sandbox/