WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] xenstore -- read UUID

To: "dinesh chandrasekaran" <dinesh_chan8@xxxxxxxxxxx>
Subject: Re: [Xen-devel] xenstore -- read UUID
From: Tej <bewith.tej@xxxxxxxxx>
Date: Wed, 10 Sep 2008 10:41:49 +0530
Cc: derek.murray@xxxxxxxxxxxx, xen developers community <xen-devel@xxxxxxxxxxxxxxxxxxx>, xen users community <xen-users@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 09 Sep 2008 22:12:12 -0700
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=SA6EIJFaEwwfwXcI6sFjX3JDK2qUNbKzAM2gzvV6l74=; b=Ud8qkMubdAThjJXE2p/XPszDx3pRp9yD1LazJp1AtM0KIkCIGb3xfCSZ6+Ll99aMIU v8DluTZ+8QzbiMURDhr9Px6XCwLhEOVj4FOagGnZGvWg4N45fFsGfH3+cO/uP9C4ak6T GwL7YEi68yhHIYK0SLtCdpbKmL0MUTLR4LoNQ=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=DWtDfD7+PKIDHQDhFIsRDIoWSarhmU0LXg5HM0UdyFU9IGLCEQBmzlafFIzRJhpZCU VRKwR8tITGWCBrD738DWiCSdJAX4tM6e8pWWiYDmCaG/u5/dD3Y+LAmPm+Dfy6nDxMhf 4FEg8rC9shWxwTsQp1SkOjohj+vAfZtDH13tM=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <BAY111-W4338D41633B4507912CC87B1570@xxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <BAY111-W4338D41633B4507912CC87B1570@xxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On 9/10/08, dinesh chandrasekaran <dinesh_chan8@xxxxxxxxxxx> wrote:
>
>
> Hi Derek,
>
> they were 2 seperate questions... sorry for the typos...
> How to access xenstore from Dom-0? -- which you said 'YES'...
> And How to access xenstore from hypervosor?

Hypervisor does not control the xenstore.
& I am not sure if xen bus interface is available to Hypervisor also.


> Yes.. as you said 'make xen' doesnt include /usr/include libraries and I did
> check that...
>
> If the hypervisor has no knowledge about XenStore, Dom-0 must have the full
> control over the xenstore.
> I need to build a table with some fields one of which should never change
> during a VMs lifetime.
> For example, if I chose the domain_id whose value is transient, If the VM
> reboots, its domain_id changes.
> That is the reason why I opted for the UUID of a domain that persists over
> time even after migration to another machine.
> The only way I could get a domain's UUID is through the xenstore and want to
> take away domain-0 from the picture, which
> according to you is almost impossible.

As far as source code compilation is cocerned try this
gcc <source file> -F /path/to/xensourcecode/tools/xenstore -lxenstore
actually xen source code will have a xen store shared object, you
definately need to use that (libxenstore.so.3.0.0)

HTH

thanks
-TEJ

>
> anyway out?
>
> regards,
> Dinesh C
>
>> Date: Tue, 9 Sep 2008 21:37:57 +0100
>> From: Derek.Murray@xxxxxxxxxxxx
>> To: dinesh_chan8@xxxxxxxxxxx
>> Subject: Re: [Xen-devel] xenstore -- read UUID
>> CC: xen-devel@xxxxxxxxxxxxxxxxxxx; xen-users@xxxxxxxxxxxxxxxxxxx
>>
>> Hi Dinesh,
>>
>> In what context are you trying to run this code? You say that you want
>> to read the UUID from Dom0, but xen/common/memory.c is part of the
>> hypervisor (and not Dom0). If you try to compile that code into
>> xen/common/memory.c, it will fail, because building the hypervisor
>> does not include the user-space headers (i.e. the contents of
>> /usr/include/).
>>
>> The hypervisor has (almost) no knowledge about XenStore, and so it
>> would be very difficult to access XenStore from there. However, if you
>> want to access this information in Dom0, your code should work in a
>> user-space application.
>>
>> Could you provide more details about what you are trying to do?
>>
>> Regards,
>>
>> Derek Murray.
>>
>> On Tue, Sep 9, 2008 at 8:36 PM, dinesh chandrasekaran
>> <dinesh_chan8@xxxxxxxxxxx> wrote:
>> > Hi All,
>> >
>> >      Im trying to read the UUID of a domain-U from domain-0 using the
>> > following code from inside say xen/common/memory.c.
>> >
>> > The include file <xs.h> is present both in /usr/include and
>> > tools/xenstore/xs.h
>> >
>> > #include <xs.h>
>> > static int get_domain_uuid(unsigned int domain_id) {
>> >         struct xs_handle *xs;
>> >         xs_transaction_t t;
>> >         char *path;
>> >         unsigned int *len;
>> >         void *uuid;
>> >         xs = xs_daemon_open();
>> >         if (xs == NULL)
>> >                 return 1;
>> >         path = xs_get_domain_path(xs, domain_id);
>> >         if (path == NULL)
>> >                 return 1;
>> >         strcat (path, '/uuid');
>> >         len = strlen(path) + 1;
>> >         uuid = xs_read(xs, t, path, len);
>> >         printf('%lx \n', (char) (*uuid));
>> >         xs_daemon_close(xs);
>> >         free(path);
>> >         return 0;
>> > }
>> >
>> > when compiled throws an error ( xs.h - no such file or directory).
>> >
>> > How to access xenstore and read the doamin UUID from dom-0 specifically
>> > from
>> > inside xen/common/memory.c?
>> >
>> > regards,
>> > Dinesh C
>> >
>> > ________________________________
>> > Voice your opinion on the burning issues of the day. Discuss, debate
>> > with
>> > the world. Logon to message boards on MSN. Try it!
>> > _______________________________________________
>> > Xen-devel mailing list
>> > Xen-devel@xxxxxxxxxxxxxxxxxxx
>> > http://lists.xensource.com/xen-devel
>> >
>> >
>
> _________________________________________________________________
> Searching for the best deals on travel? Visit MSN Travel.
> http://in.msn.com/coxandkings

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>