Re: [Qemu-devel] [PATCH RFC 1/2] block: Factor bdrv_probe_all() out of find_image_format()

[Jeff Cody <jcody@redhat.com>]

On Tue, Oct 28, 2014 at 05:03:39PM +0100, Markus Armbruster wrote:
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  block.c | 45 ++++++++++++++++++++++++++++++++-------------
>  1 file changed, 32 insertions(+), 13 deletions(-)
> 
> diff --git a/block.c b/block.c
> index 88f6d9b..8da6e61 100644
> --- a/block.c
> +++ b/block.c
> @@ -644,11 +644,40 @@ BlockDriver *bdrv_find_protocol(const char *filename,
>      return NULL;
>  }
>  
> +/*
> + * Guess image format by probing its contents.
> + * This is not a good idea when your image is raw (CVE-2008-2004), but
> + * we do it anyway for backward compatibility.
> + * @buf contains the image's first @buf_size bytes.
> + * @buf_size is 2048 or the image's size, whatever is smaller.
> + * @filename is its filename.
> + * For all block drivers, call the bdrv_probe() method to get its
> + * probing score.
> + * Return the first block driver with the highest probing score.
> + */
> +static BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
> +                                   const char *filename)
> +{
> +    int score_max = 0, score;
> +    BlockDriver *drv = NULL, *d;
> +
> +    QLIST_FOREACH(d, &bdrv_drivers, list) {
> +        if (d->bdrv_probe) {
> +            score = d->bdrv_probe(buf, buf_size, filename);
> +            if (score > score_max) {
> +                score_max = score;
> +                drv = d;
> +            }
> +        }
> +    }
> +
> +    return drv;
> +}
> +
>  static int find_image_format(BlockDriverState *bs, const char *filename,
>                               BlockDriver **pdrv, Error **errp)
>  {
> -    int score, score_max;
> -    BlockDriver *drv1, *drv;
> +    BlockDriver *drv;
>      uint8_t buf[2048];
>      int ret = 0;
>  
> @@ -671,17 +700,7 @@ static int find_image_format(BlockDriverState *bs, const char *filename,
>          return ret;
>      }
>  
> -    score_max = 0;
> -    drv = NULL;
> -    QLIST_FOREACH(drv1, &bdrv_drivers, list) {
> -        if (drv1->bdrv_probe) {
> -            score = drv1->bdrv_probe(buf, ret, filename);
> -            if (score > score_max) {
> -                score_max = score;
> -                drv = drv1;
> -            }
> -        }
> -    }
> +    drv = bdrv_probe_all(buf, ret, filename);
>      if (!drv) {
>          error_setg(errp, "Could not determine image format: No compatible "
>                     "driver found");
> -- 
> 1.9.3
>

Reviewed-by: Jeff Cody <jcody@redhat.com>