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. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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