From: Eric Hodel <drbrain@...7.net>
Date: 2004-01-03T22:38:38-08:00
Subject: Re: successive chroots thanks to continuations?

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Bauduin Raphael (rb@raphinou.com) wrote:

> Hi again,
>=20
> I have defined several chrooted environments on my computer.
> I'd like to issue the same command(s) in each of them. In a shell
> I can do it with a for loop (example chrooting 2 successives times to
> the same chroot)
>=20
> for f in "/mnt/test-chroot/"  "/mnt/test-chroot/"; do chroot $f ls -a=20
> /mnt; done
>=20
> I wondered if I could do it in Ruby using Dir.chroot.
> The problem is that this changes the root for the running script,
> and getting out of it is not possible (I suppose).
> Having just read that continuations saved the whole context when it is
> created, I thought to use it, but it doesn't work (script below chroots
> correctly the first time, but not the second).
>=20
> Is what I am trying to do possible?

The command above uses chroot(8) to run the command in a subshell.
Ruby's chroot uses chroot(2) which is permanent.  You would have to use
fork get around this.

> #!/usr/bin/ruby1.8
> ["/mnt/test-chroot","/mnt/test-chroot"].each do |dir|
    fork do
> 		p "will chroot to "+dir
> 		Dir.chroot(dir)
> 	=09
> 		p "will list files in /mnt for chroot " + dir
> 		Dir.foreach("/mnt") {|f| p f}
> 	=09
> 		p "*"*80
  	end
> end

--=20
Eric Hodel - drbrain@segment7.net - http://segment7.net
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