Re: [PATCH] libxl: prevent xl from running if xend is running.

[Roger Pau Monne <roger.pau@citrix.com>]

Ian Campbell escribió:
> On Tue, 2012-04-24 at 15:47 +0100, Ian Jackson wrote:
>> Ian Campbell writes ("Re: [Xen-devel] [PATCH] libxl: prevent xl from running if xend	is running."):
>>> You could consider this to be a best effort check for xend. IOW we try
>>> and look but if we can't tell then we assume it is not.
>> I guess.
>>
>>> It's not terribly robust to just blunder on, but on the other hand being
>>> more robust has a bigger risk of false positives, e.g. failing to start
>>> xl because /var/lock/subsys/ does not exist isn't especially helpful
>>> either (the EACCESS return code doesn't distinguish that
>>> from /var/lock/subsys/xend not existing).
>> EACCES would happen only if the permissions prevented us from
>> looking.  If /var/lock/subsys doesn't exist we'll get ENOENT, the
>> "good" error return.
>
> Oh, right.
>
> Well, not starting because the perms on /var/lock/subsys are too tight
> (e.g. selinux restricting it to initscripts only? unrealistic maybe)
> seems unhelpful too.
>
> (I admit this isn't as compelling as my previous example).
>
> Ian.
>

What have we decided at the end? Should I do an inverse check, and run 
only if access(...) != 0 && errno == ENOENT?

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