Re: [Xen-devel] [PATCH] DOM0_GETDOMAININFO hypercall support for DOMID_SELF

[Anthony Liguori <aliguori@xxxxxxxxxx>]

Cihula, Joseph wrote:

> The attached (and following) patch allows a privileged domain to use the
> DOM0_GETDOMAININFO dom0_op (and by extension, userspace apps to use
> xc_domain_getinfo()) to query about themselves by specifying the domid
> as DOMID_SELF.
>
> Most importantly, this allows the domain to determine its own domid.
>  
If you want to find out your domid (you'll have to be very careful wrt 
save/restore/migrate btw) what you can do today is:
1) Copy libxenctrl.so.3.0.0, libxenstore.so, and xenstore-read into your 
guest.
2) xenstore-read domid

This will work in any type of domain.  You can also just use libxenstore 
directly (just make sure to use xs_domain_open()).
Regards,

Anthony Liguori

> Signed-off-by: joseph.cihula@xxxxxxxxx
>
> diff -r 6ee4c16bfdec xen/common/dom0_ops.c
> --- a/xen/common/dom0_ops.c     Fri Dec 16 17:58:21 2005
> +++ b/xen/common/dom0_ops.c     Fri Dec 16 18:40:39 2005
> @@ -358,12 +358,17 @@
>     case DOM0_GETDOMAININFO:
>     {
>         struct domain *d;
> +        domid_t dom;
> +
> +        dom = op->u.getdomaininfo.domain;
> +        if ( dom == DOMID_SELF )
> +            dom = current->domain->domain_id;
>
>         read_lock(&domlist_lock);
>
>         for_each_domain ( d )
>         {
> -            if ( d->domain_id >= op->u.getdomaininfo.domain )
> +            if ( d->domain_id >= dom )
>                 break;
>         }
>
>  
>
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>
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