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[Xen-devel] Re: [Pkg-xen-devel] xen 4.1 blktap2 support

To: Ian Campbell <ijc@xxxxxxxxxxxxxx>
Subject: [Xen-devel] Re: [Pkg-xen-devel] xen 4.1 blktap2 support
From: Bastian Blank <waldi@xxxxxxxxxx>
Date: Fri, 29 Apr 2011 13:08:08 +0200
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On Thu, Apr 28, 2011 at 03:20:58PM +0100, Ian Campbell wrote:
> On Thu, 2011-04-28 at 14:27 +0200, Bastian Blank wrote:
> > - Silent fail if qemu-dm[1] is missing or failing. It lacks error
> >   checking.
> Yes, this could certainly be improved.

A hang without any feedback is the worst user-experience possible.

> > - Probably missing close-on-exit flags for several file handlers.
> You mean close-on-exec?


> the libxl interfaces for exec'ing takes care of closing file handles and

It tries to, but it can't ever succeed (there is no practical upper
limit for the fd value). Usually this is used to _hide_ other errors.

> Do you know of specific instances where the CLOEXEC flag is needed but
> missing?

Not right now. But because of the hiding properties it is not possible
to detect without changes anyway.

> I don't think any of the above qualifies xl as so broken we shouldn't
> even suggest people try it, as you started out by saying...

Failing without feedback and only running in an environment not
security supportable is broken.


Without followers, evil cannot spread.
                -- Spock, "And The Children Shall Lead", stardate 5029.5

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