[Qemu-devel] [PATCH v4] raw-posix: Detect CDROM via ioctl on linux

[Qemu-devel] [PATCH v4] raw-posix: Detect CDROM via ioctl on linux

[Cole Robinson]

Current CDROM detection is hardcoded based on source file name.
Make this smarter on linux by attempting a CDROM specific ioctl.

This makes '-cdrom /dev/sr0' succeed with no media present.

v2:
    Give ioctl check higher priority than filename check.

v3:
    Actually initialize 'prio' variable.
    Check for ioctl success rather than absence of specific failure.

v4:
    Explicitly mention that change is linux specific.

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 5a6a22b..a2c7508 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;
+    int prio = 0;
+
     if (strstart(filename, "/dev/cd", NULL))
-        return 100;
-    return 0;
+        prio = 50;
+
+    fd = open(filename, O_RDONLY | O_NONBLOCK);
+    if (fd < 0) {
+        goto out;
+    }
+
+    /* Attempt to detect via a CDROM specific ioctl */
+    ret = ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
+    if (ret >= 0)
+        prio = 100;
+
+    close(fd);
+out:
+    return prio;
 }
 
 static int cdrom_is_inserted(BlockDriverState *bs)
-- 
1.6.5.2

Re: [Qemu-devel] [PATCH v4] raw-posix: Detect CDROM via ioctl on linux

[Anthony Liguori]

On 01/14/2010 10:19 AM, Cole Robinson wrote:
> Current CDROM detection is hardcoded based on source file name.
> Make this smarter on linux by attempting a CDROM specific ioctl.
>
> This makes '-cdrom /dev/sr0' succeed with no media present.
>
> v2:
>      Give ioctl check higher priority than filename check.
>
> v3:
>      Actually initialize 'prio' variable.
>      Check for ioctl success rather than absence of specific failure.
>
> v4:
>      Explicitly mention that change is linux specific.
>
> Signed-off-by: Cole Robinson<crobinso@redhat.com>
>    

Applied.  Thanks.

Regards,

Anthony Liguori
> ---
>   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 5a6a22b..a2c7508 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;
> +    int prio = 0;
> +
>       if (strstart(filename, "/dev/cd", NULL))
> -        return 100;
> -    return 0;
> +        prio = 50;
> +
> +    fd = open(filename, O_RDONLY | O_NONBLOCK);
> +    if (fd<  0) {
> +        goto out;
> +    }
> +
> +    /* Attempt to detect via a CDROM specific ioctl */
> +    ret = ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
> +    if (ret>= 0)
> +        prio = 100;
> +
> +    close(fd);
> +out:
> +    return prio;
>   }
>
>   static int cdrom_is_inserted(BlockDriverState *bs)
>