From: Anthony Liguori <anthony@codemonkey.ws>
To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>,
Tyler C Hicks <tchicks@us.ibm.com>,
Corey Bryant <bryntcor@us.ibm.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] Add support for fd: protocol
Date: Mon, 23 May 2011 07:59:40 -0500 [thread overview]
Message-ID: <4DDA5A3C.1010500@codemonkey.ws> (raw)
In-Reply-To: <20110523103027.GD24143@redhat.com>
On 05/23/2011 05:30 AM, Daniel P. Berrange wrote:
> It feels to me that turning the current block driver code which just does
> open(2) on files, into something which issues events& asynchronously
> waits for a file would potentially be quite complex.
>
> You also need to be much more careful from a security POV if the mgmt
> app is accepting requests to open arbitrary files from QEMU, to ensure
> the filenames are correctly/strictly validated before opening them and
> giving them back to QEMU. An architecture where the mgmt app decides
> what FDs to supply upfront, has less potential for security errors.
>
> To me the ideal would thus be that we can supply FDs for the backing
> store with -blockdev syntax, and that places where QEMU re-opens files
> would be enhanced to avoid that need. If there are things we can't do
> without closing& re-opening the same file, then perhaps we need some
> new ioctl()/fcntl() calls to change those file attributes on the fly.
I agree. But my view of blockdev is that you wouldn't set an fd
attribute but rather the backing file name and use the fd protocol. For
instance:
-blockdev id=foo-base,path=fd:4,format=raw
-blockdev id=foo,path=fd:3,format=qcow2,backing_file=foo
> Regards,
> Daniel
next prev parent reply other threads:[~2011-05-23 12:59 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-20 18:48 [Qemu-devel] [PATCH] Add support for fd: protocol Corey Bryant
2011-05-20 19:05 ` Anthony Liguori
2011-05-20 19:25 ` Blue Swirl
2011-05-20 19:42 ` Anthony Liguori
2011-05-20 19:53 ` Blue Swirl
2011-05-23 14:28 ` Kevin Wolf
2011-05-23 15:24 ` Markus Armbruster
2011-05-23 15:56 ` Kevin Wolf
2011-05-23 19:50 ` Blue Swirl
2011-05-23 21:55 ` Anthony Liguori
2011-05-23 18:20 ` Corey Bryant
2011-05-23 9:45 ` Daniel P. Berrange
2011-05-23 10:19 ` Stefan Hajnoczi
2011-05-23 10:30 ` Daniel P. Berrange
2011-05-23 12:59 ` Anthony Liguori [this message]
2011-05-23 14:35 ` Markus Armbruster
2011-05-23 22:49 ` Jamie Lokier
2011-05-24 8:39 ` Stefan Hajnoczi
2011-05-24 15:31 ` Jamie Lokier
2011-05-23 12:50 ` Anthony Liguori
2011-05-23 13:06 ` Daniel P. Berrange
2011-05-23 13:09 ` Stefan Hajnoczi
2011-05-23 13:21 ` Anthony Liguori
2011-05-23 13:26 ` Stefan Hajnoczi
2011-05-23 13:42 ` Daniel P. Berrange
2011-05-23 9:48 ` Daniel P. Berrange
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