Re: [Xen-devel] [PATCH] Add an ioctl interface for simple xenstore access

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 18 Mar 2006, at 18:02, Anthony Liguori wrote:

> We had discussed this in a previous thread and I thought you were okay 
> with this approach.  The /proc/xen/xenbus interface requires full 
> parsing of the XenBus protocol.  This requires libxenstore in domU.  
> Today, libxenstore is shipped with the rest of the tools package on 
> most distros.  If one wants to write a Xen-aware application for a 
> domU, that brings in a pretty large number of unnecessary 
> dependencies.  Also, for 32 bit management apps in a 64 bit 
> environment, it makes things very nasty (should we build a 32 bit and 
> 64 bit version of libxenstore?  Is the protocol 32/64 bit safe?).
> Ideally, an app could just use a simple interface to /proc/xen/xenbus 
> to access XenStore.  That solves all of the above problems elegantly.  
> An ioctl() interface seemed like the most obvious approach that 
> wouldn't break existing apps.  Of course, any suggestion for a better 
> interface would be appreciated.
Either way you're going to have an abstraction layer in your apps that 
hides the grotty details of how you access xenstore via 
/proc/xen/xenbus, whether it's via the read/write interface or via 
ioctls. That given, why not just statically link with libxenstore, or 
even include xs.h, xs.c and xs_lib.c in your applications? They're 
small, so no significant bloat, and LGPL, so no fear of GPL bleed into 
your management apps.
The protocol is 32/64-bit safe.

 -- Keir


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