Mailing List Archive

[PATCH][libxen] Fix 'contents' field of set structures in libxen iinterface
Many of the set structures in the libxen interface contain a 'contents'
field with too many dimensions, particularly when 'contents' stores
references. References are defined in the various xen_*_decl.h headers
as 'void *'. Sets of the various classes are defined for example as

typedef void *xen_vm;

typedef struct xen_vm_set
{
size_t size;
xen_vm *contents[];
} xen_vm_set;

The additional dimension on 'contents' for sets of references is not
required.

- Jim
Re: [PATCH][libxen] Fix 'contents' field of set structures in libxen iinterface [ In reply to ]
On Fri, Nov 03, 2006 at 05:41:31PM -0700, Jim Fehlig wrote:

> Many of the set structures in the libxen interface contain a 'contents'
> field with too many dimensions, particularly when 'contents' stores
> references. References are defined in the various xen_*_decl.h headers
> as 'void *'. Sets of the various classes are defined for example as
>
> typedef void *xen_vm;
>
> typedef struct xen_vm_set
> {
> size_t size;
> xen_vm *contents[];
> } xen_vm_set;
>
> The additional dimension on 'contents' for sets of references is not
> required.
>

I meant to discuss this with you when you sent this privately a few weeks
ago -- sorry I forgot.

I can see what you're trying to do here. The problem is that populating this
set becomes difficult. The sets are read off the wire using the generic
code in xen_common.c, guided by the abstract_type that's passed in. The thing
is, we have only one indicator for sets (SET) but with your patch we'll need
to introduce a second indicator, to distinguish between sets where the value
is put in place (like handles) and sets where the value placed is a pointer
(like sets of records). This will have to be part of a larger patch,
unfortunately. I'll have a hack now and see what I can do.

Cheers,

Ewan.

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