Re: [Qemu-devel] [PATCH v2] raw-posix: Detect legacy floppy via ioctl

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 01/12/2010 09:29 AM, Cole Robinson wrote:
> Current legacy floppy detection is hardcoded based on source file
> name. Make this smarter by attempting a floppy specific ioctl.
>
> v2: Give ioctl check higher priority than filename check,
>      s/IDE/legacy/
>
> Signed-off-by: Cole Robinson<crobinso@redhat.com>
> ---
>   block/raw-posix.c |   20 ++++++++++++++++++--
>   1 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index b7254d8..d67280e 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -1055,9 +1055,25 @@ static int floppy_open(BlockDriverState *bs, const char *filename, int flags)
>
>   static int floppy_probe_device(const char *filename)
>   {
> +    int fd, ret, prio;
> +    struct floppy_struct fdparam;
> +
>       if (strstart(filename, "/dev/fd", NULL))
> -        return 100;
> -    return 0;
> +        prio = 50;
> +
> +    fd = open(filename, O_RDONLY | O_NONBLOCK);
> +    if (fd<  0) {
> +        goto out;
> +    }
> +
> +    /* Attempt to detect via a floppy specific ioctl */
> +    ret = ioctl(fd, FDGETPRM,&fdparam);
> +    if (!(ret<  0&&  errno == EINVAL))
>    

These two patches break boot from an image file.  My suspicious is that 
it's failing because the errno is ENOSYS.

You probably want to do the opposite and check for a positive return 
result instead of checking for the absence of a positive result.

Regards,

Anthony Liguori