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From: "Anthony G. Basile" <basile@opensource.dyc.edu>
To: gentoo-embedded@lists.gentoo.org
Subject: Re: [gentoo-embedded] Qemu-user chroot handbook chapter - mdev issue
Date: Wed, 23 Jul 2014 07:41:52 -0400	[thread overview]
Message-ID: <53CF9F80.8040109@opensource.dyc.edu> (raw)
In-Reply-To: <CAL=Nhm4m4dQYP+9nzwwSh2ecrWeFoBZuLaB2C8H_4+buTqR1JQ@mail.gmail.com>

On 07/22/14 15:28, Phil Tooley wrote:
> Hi all,
>
> I have been looking at the handbook section regarding a qemu-user chroot
> and have some serious concerns about part of it.  Specifically, in the
> section for setting up the chroot it is suggested to run
>
> chroot . /bin/busybox mdev -s
>
> Since I (like most others) am currently running udev, this seems to me like
> a very bad idea.  (And indeed this is confirmed when I try it on my dev VM,
> where the permissions for /dev/pts /dev/null /dev/random etc. are messed up
> by this)
>
> Can someone please explain the logic here, since as far as I can tell so
> far, simply omitting this step does no major harm.
>
> Cheers
>
> Phil Tooley
>

Read the mdev primer:

http://git.busybox.net/busybox/tree/docs/mdev.txt

Basically it does a population of /dev via /sys and if it has a config 
file, will set permissions.

So if you omit this step you may have a <chroot>/dev which has incorrect 
permissions for your chroot.

If you are running a chroot and you `mount --bind /dev <chroot>/dev` 
then changing the permissions in /dev may mess up your real root.

My recommendation is to not do a bind mount and just populate a fresh 
<chroot>/dev.

-- 
Anthony G. Basile, Ph. D.
Chair of Information Technology
D'Youville College
Buffalo, NY 14201
(716) 829-8197


      reply	other threads:[~2014-07-24 22:49 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-22 19:28 [gentoo-embedded] Qemu-user chroot handbook chapter - mdev issue Phil Tooley
2014-07-23 11:41 ` Anthony G. Basile [this message]

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