Re: [Qemu-devel] [PATCH] block.c: fix real cdrom detection

[John Snow <jsnow@redhat.com>]

On 06/23/2015 01:56 PM, Programmingkid wrote:
> Fix real cdrom detection so that a real cdrom can actually be used.
> 
> signed-off-by: John Arbuckle <programmingkidx@gmail.com
> <mailto:programmingkidx@gmail.com>>
> 
> This patch has been tested on Mac OS X host and guest. 
> Command used: qemu-system-ppc -cdrom /dev/cdrom
> 
> Note: I was able to view the files using OpenBIOS, but not on 
> Mac OS X. The size of the disc is reported correctly but some
> error happens that prevents it from mounting in Mac OS X. This
> is probably another bug with QEMU.
> 
> ---
>  block.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/block.c b/block.c
> index dd4f58d..75ccfad 100644
> --- a/block.c
> +++ b/block.c
> @@ -583,7 +583,8 @@ static int find_image_format(BlockDriverState *bs,
> const char *filename,
>      int ret = 0;
> 
>  
> 
>      /* Return the raw BlockDriver * to scsi-generic devices or empty
> drives */
> -    if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
> +    if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0 
> +               || strcmp("/dev/cdrom", filename) == 0) {
>          *pdrv = &bdrv_raw;
>          return ret;
>      }
> -- 
> 1.7.5.4
> 

So what's the issue that this patch attempts to fix and how did you
determine that the fix was needed here? It doesn't look like it respects
proper abstraction at a glance.

--js