From: Bertram Scharpf <lists@...>
Date: 2005-02-02T06:13:56+09:00
Subject: Re: $SAFE doesn't work as specified?

Hi Assaph,

Am Dienstag, 01. Feb 2005, 06:50:45 +0900 schrieb Assaph Mehr:
> > the Chapter "Locking Ruby in the Safe" says this should
> > work:
> 
> This is the expected behaviour: inside the thread you create you set
> the $SAFE level to 4, meaning that from here on within the thread you
> can't access variables from outside the thread scope. What you can do
> is either hardcode the file name in the #load or pass an argument to
> the thread:
> 
> | Thread.start(File.expand_path(fn)) { |fn|
> |   $SAFE = 4
> |   load fn, true
> | }.join
> 
> The expand_path is because you cannot load a relative path when in
> $SAFE >= 2.

Thank you very much for your detailed answer. I'm afraid to
say the program still doesn't work:

  $ cat safe.rb
  fn = 'dummy.rb'
  File.open fn, 'w' do |f|
    f.puts 'raise "hello"'
  end
  Thread.start( File.expand_path( fn)) do |fn|
    $SAFE = 4
    load fn, true
  end.join

  $ ruby safe.rb
  safe.rb:7:in `load': Insecure operation - load
  (SecurityError)
          from safe.rb:5:in `join'
          from safe.rb:5
  $

All I wanted to do is run the thread in its own environment.
I will use fork.

Bertram

-- 
Bertram Scharpf
Stuttgart, Deutschland/Germany
http://www.bertram-scharpf.de