Re: [Qemu-devel] [PATCH] raw-posix: Detect CDROM via ioctl

[Simon Horman]

On Mon, Jan 11, 2010 at 01:30:18PM -0500, Cole Robinson wrote:
> Current CDROM detection is hardcoded based on source file name.
> Make this smarter by attempting a CDROM specific ioctl.
> 
> This makes '-cdrom /dev/sr0' succeed with no media present.
> 
> Signed-off-by: Cole Robinson <address@hidden>
> ---
>  block/raw-posix.c |   18 +++++++++++++++++-
>  1 files changed, 17 insertions(+), 1 deletions(-)
> 
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 5a6a22b..3ec58d0 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -1140,9 +1140,25 @@ static int cdrom_open(BlockDriverState *bs, const char 
> *filename, int flags)
>  
>  static int cdrom_probe_device(const char *filename)
>  {
> +    int fd, ret;
> +
>      if (strstart(filename, "/dev/cd", NULL))
>          return 100;
> -    return 0;
> +
> +    fd = open(filename, O_RDONLY | O_NONBLOCK);
> +    if (fd < 0) {
> +        return 0;
> +    }
> +
> +    /* Attempt to detect via a CDROM specific ioctl */
> +    if (ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT) < 0 && errno == EINVAL) {
> +        ret = 0;
> +    } else {
> +        ret = 100;
> +    }
> +
> +    close(fd);
> +    return ret;
>  }
>  
>  static int cdrom_is_inserted(BlockDriverState *bs)

Does this render the remaining "/dev/cd" check unnecessary?
Likewise for the similar change that you posted for floppies.