Re: [Qemu-devel] [PATCH] raw-posix.c: remove raw device access for cdrom

[Paolo Bonzini <pbonzini@redhat.com>]

On 02/07/2015 00:13, Programmingkid wrote:
> Fix real cdrom access in Mac OS X so it can be used in QEMU.
> It simply removes the r from a device file's name. This
> allows for a real cdrom to be accessible to the guest.
> It has been successfully tested with a Windows XP guest
> in qemu-system-i386. The qemu-system-ppc emulator doesn't
> quit anymore, but there is another problem that prevents a 
> real cdrom from working.
> 
> Signed-off-by: John Arbuckle <programmingkidx@gmail.com
> <mailto:programmingkidx@gmail.com>>
> 
> ---
>  block/raw-posix.c |   10 ++++++++++
>  1 files changed, 10 insertions(+), 0 deletions(-)
> 
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index a967464..3585ed9 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -2096,6 +2096,16 @@ static int hdev_open(BlockDriverState *bs, QDict
> *options, int flags,
>          kernResult = FindEjectableCDMedia( &mediaIterator );
>          kernResult = GetBSDPath( mediaIterator, bsdPath, sizeof(
> bsdPath ) );
> 
>  
> 
> +        /*
> +         * Remove the r from cdrom block device if needed.
> +         * /dev/rdisk1 would become /dev/disk1.
> +         * The r means raw access. It doesn't work well.
> +         */
> +        int sizeOfString = strlen("/dev/r");
> +        if (strncmp("/dev/r", bsdPath, sizeOfString) == 0) {
> +            sprintf(bsdPath, "/dev/%s", bsdPath + sizeOfString);
> +        }

I think you can just remove the strcat in here:

        if ( bsdPathAsCFString ) {
            size_t devPathLength;
            strcpy( bsdPath, _PATH_DEV );
            strcat( bsdPath, "r" );
            devPathLength = strlen( bsdPath );
            if ( CFStringGetCString( bsdPathAsCFString, bsdPath +
devPathLength, maxPathSize - devPathLength, kCFStringEncodingASCII ) ) {
                kernResult = KERN_SUCCESS;
            }
            CFRelease( bsdPathAsCFString );

So it's still a one-line change.  What are the other consequences of
removing the "r"?

Paolo

>          if ( bsdPath[ 0 ] != '\0' ) {
>              strcat(bsdPath,"s0");
>              /* some CDs don't have a partition 0 */
> -- 
> 1.7.5.4
>