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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Matthew Daley <mattd@bugfuzz.com>,
	Ian Campbell <ian.campbell@citrix.com>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH] xenconsole: merge pty access check into when it is opened
Date: Mon, 2 Dec 2013 11:53:46 +0000	[thread overview]
Message-ID: <529C74CA.6020606@citrix.com> (raw)
In-Reply-To: <21148.29748.198188.50940@mariner.uk.xensource.com>

On 02/12/13 11:51, Ian Jackson wrote:
> Andrew Cooper writes ("Re: [Xen-devel] [PATCH] xenconsole: merge pty access check into when it is opened"):
>> On 01/12/2013 23:14, Matthew Daley wrote:
>>> On Mon, Dec 2, 2013 at 12:41 AM, Andrew Cooper
>>> <andrew.cooper3@citrix.com> wrote:
>>>> access() can fail for many more reasons than just EACCES.  I would skip
>>>> the errno check entirely and always print the error.
>>> err() doesn't return though (calls exit()). Given that, is always
>>> calling it still acceptable?
> ...
>> Even as the patch currently stands, the behaviour of the loop has
>> changed. Before, it would eat any error from access(), and only die in
>> the toctou case where open() subsequently failed.
> I had the impression there is sometimes a race during domain startup,
> between a toolstack invoking xenconsole and xenconsoled allocating the
> pty.
>
> Ian.

In which case the xenstore path should be NULL and we wander around loop
and wait on the watch again.

~Andrew

  reply	other threads:[~2013-12-02 11:53 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-30  3:42 [PATCH] xenconsole: merge pty access check into when it is opened Matthew Daley
2013-12-01 11:41 ` Andrew Cooper
2013-12-01 23:14   ` Matthew Daley
2013-12-01 23:29     ` Andrew Cooper
2013-12-02  2:41       ` [PATCH v2] " Matthew Daley
2013-12-02 10:30         ` Andrew Cooper
2013-12-13  5:59         ` Matthew Daley
2013-12-02 11:51       ` [PATCH] " Ian Jackson
2013-12-02 11:53         ` Andrew Cooper [this message]
2013-12-13 17:01     ` [PATCH] xenconsole: merge pty access check into when it is opened [and 1 more messages] Ian Jackson
2013-12-13 22:54       ` Matthew Daley
2013-12-14  1:04       ` [PATCH v3] xenconsole: adjust pty opening error checking and handling Matthew Daley
2013-12-16 11:58         ` Ian Jackson

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