Date: Tue, 2 Jun 1998 19:55:49 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: mike@smith.net.au (Mike Smith) Cc: tlambert@primenet.com, mike@smith.net.au, bag@sinbin.demos.su, eivind@yes.no, sepotvin@videotron.ca, current@FreeBSD.ORG Subject: Re: I see one major problem with DEVFS... Message-ID: <199806021955.MAA03610@usr06.primenet.com> In-Reply-To: <199806020042.RAA02307@dingo.cdrom.com> from "Mike Smith" at Jun 1, 98 05:42:07 pm
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> > Since it's the same space, you could hard link from your devfs into
> > the empty one to create the nodes.
> >
> > This is even better, since it allows a chroot in a chroot to never
> > inherit more than the parent. 8-).
>
> However it is problematic to link outside of a chroot, and it may not
> always be desirable to be so fancy (eg. when using chroot for
> engineering rather than security reasons).
Not the same thing. I'm talking about:
-----------+---+-------------------+-----------+------- chroot 2
| | | |
-------+---+---+-----------+-------+-----------+------- chroot 1
| | | | | |
---+---+---+---+---+---+---+---+---+---+---+---+---+--- system
| | | | | | | | | | | | |
---+---+---+---+---+---+---+---+---+---+---+---+---+--- template
chroot 1 and chroot 2 were populated from system using the link(2)
call, which worked "across" devfs instances.
> > > DEVFS is per-system. You cannot export a DEVFS via NFS (it makes no
> > > sense to do so - devices there are only relevant to the host system).
>
> No, it's a direct feature of DEVFS, or more particularly to achieve the
> results desired by the original poster you cannot use an NFS-mounted
> devfs.
???
You'd have to restate your understanding of the results; from mine, I
was under the impression they were talking about remote mounts of
NFS roots.
There is also the problem of non-devfs capable kernels remote NFS root
mounting from FreeBSD -- this one requires the ability referesent device
node for remote use, even if they locally have no meaning.
> > For normal devices that are only operated on via open/close/read/write,
> > it makes sens to export a devfs.
>
> No, it does not. There is no identifying information exported with a
> DEVFS node that allows the local system to correctly connect a node
> from a remote DEVFS (which may not map to a local driver) to a local
> device.
The vnode *is* the device. No connection is necessary.
Terry Lambert
terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.
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