> > I want to say things like evil.rb code can write to "evil.log" but to
> > nothing else.
> > How can use threads to say this kind of things with threads?
>
> Since you don't want to use $SAFE, the answer really is:
>
> There is no pretty prepackaged way to do what you want to do.  You can
> certainly try writing it yourself, and good luck with that if you do, but a
> solution using $SAFE is the only thing that will get you close to what you
> want in the short term.
>
>
> Kirk Haines

That's why I've started the securedruby project
(http://securedruby.rubyforge.org). My problem is that I'm unable to
stop "evil code" to modify already defined classes. The idea of the
library (already only vaporware) is to redefine all the potentially
dangerous operations in the core library to check for permissions. But
I'm unable to add this check to method redefinition. That's why I've
started two threads on this group (this one and "method added hook").

Do you know how can I achieve it (prevent class modification in some
situations)?

Aureliano.