Re: [Qemu-stable] [Qemu-devel] [PATCH] qapi-types.py: Fix enum struct sizes on i686

[Doug Goldstein]

On Sat, Aug 31, 2013 at 9:07 PM, Eric Blake <address@hidden> wrote:

On 08/31/2013 04:36 PM, Cole Robinson wrote:
> Unlike other list types, enum wasn't adding any padding, which caused
> a mismatch between the generated struct size and GenericList struct
> size. More details in a678e26cbe89f7a27cbce794c2c2784571ee9d21
>
> This crashed qemu if calling qmp query-tpm-types for example, which
> upsets libvirt capabilities probing. Reproducer on i686:
>
> (sleep 5; printf '{"execute":"qmp_capabilities"}\n{"execute":"query-tpm-types"}\n') | ./i386-softmmu/qemu-system-i386 -S -nodefaults -nographic -M none -qmp stdio
>
> https://bugs.launchpad.net/qemu/+bug/1219207
>
> Cc: address@hidden
> Signed-off-by: Cole Robinson <address@hidden>
> ---
>  scripts/qapi-types.py | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>

Reviewed-by: Eric Blake <address@hidden>

> -    %(name)s value;
> +    union {
> +        %(name)s value;
> +        uint64_t padding;
> +    };

Am I right that anonymous unions are only a C11 feature (not C99)?  But
you are just copying and pasting from the other uses in this file, so
it's not a problem.

 

Yes, they're a C11-ism. But they appear in gnu99, not sure as to what GCC added them but I know GCC 3.2 didn't have them.

--
Doug Goldstein