From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36395) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z9WQc-0001t4-C0 for qemu-devel@nongnu.org; Mon, 29 Jun 2015 06:36:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z9WQa-0000aZ-SH for qemu-devel@nongnu.org; Mon, 29 Jun 2015 06:36:42 -0400 Message-ID: <55911FAF.4010109@redhat.com> Date: Mon, 29 Jun 2015 12:36:31 +0200 From: Laurent Vivier MIME-Version: 1.0 References: <3B3C7431-1003-4AAA-90AF-0E1A154DFBE2@gmail.com> <5589A026.5020800@redhat.com> <455CF92B-58FA-446D-9EB0-42661C23B739@gmail.com> <87pp4kxos3.fsf@blackfin.pond.sub.org> <7B989F99-B95C-4D53-AA2D-29B87634D2BB@gmail.com> <558C22BD.1020404@redhat.com> <558C2852.3050102@redhat.com> <47B5E901-9CCD-4737-A5F2-B790EBEF941A@gmail.com> <02818C70-4409-48F8-8776-0AB917B5A39F@gmail.com> <55909167.8090803@redhat.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] block.c: fix real cdrom detection List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Programmingkid Cc: Kevin Wolf , Peter Maydell , Qemu-block , qemu-devel qemu-devel , Markus Armbruster , Paolo Bonzini On 29/06/2015 05:01, Programmingkid wrote: > > On Jun 28, 2015, at 8:29 PM, Laurent Vivier wrote: > >> Hi, >> >> On 29/06/2015 01:43, Programmingkid wrote: >>> >>> On Jun 25, 2015, at 2:01 PM, Peter Maydell wrote: >>> >>>> On 25 June 2015 at 18:56, Programmingkid >>>> > wrote: >>>>> Nice to hear from you again Laurent. The only way a solution in >>>>> hdev_open() would work is if it could prevent >>>>> find_image_format() from executing. Otherwise find_image_format() >>>>> would just quit QEMU with an error. >>>> >>>> The question you should be asking is "what is Linux doing for raw >>>> CDROM devices that is different, such that it works there but >>>> doesn't work on OSX?". >>>> >>>> It would also be helpful to know which is the case that doesn't >>>> work. Does QEMU fail in all cases, or only if the cdrom drive is >>>> empty, or only if there's a disk in the drive? >>> >>> QEMU fails if the cdrom is specified "-cdrom /dev/cdrom", and there >>> is no cd in the drive. >>> >>> QEMU also fails with a real cdrom in the drive. >>> >>>> >>>> My initial suspicion is that we need OSX support in raw-posix.c for >>>> handling the host CDROM specially -- note that Linux and FreeBSD >>>> register a bdrv_host_cdrom with an is_inserted function. >>> >>> The is_inserted function wouldn't make a difference. >> >> In fact, if your patch fixes the problem, the is_inserted with no >> cdrom should too: >> >> with your " strcmp("/dev/cdrom", filename) == 0 ", you force the >> selection of bdrv_raw (which is what to do). >> >> without your patch, if "bdrv_is_inserted()" was implemented and no cdrom >> in the drive " !bdrv_is_inserted(bs) " should also select bdrv_raw. >> >> It appears also that bdrv_host_cdrom is not registered in >> bdrv_file_init(). I think this is the missing part to have a host cdrom >> support on MacOS X. >> >> Laurent > > This patch is what I came up with using your idea. It uses the fact that > the bdrv_is_inserted() function is called first from > find_image_format(). The bdrv_is_inserted() function now points > to cdrom_is_inserted(). This new function will return 0 the first time > it is called, then 1 after that. So far it works. Great. > > --- > block/raw-posix.c | 21 +++++++++++++++++++++ > 1 files changed, 21 insertions(+), 0 deletions(-) > > diff --git a/block/raw-posix.c b/block/raw-posix.c > index a967464..2d35580 100644 > --- a/block/raw-posix.c > +++ b/block/raw-posix.c > @@ -2324,6 +2324,23 @@ static int hdev_create(const char *filename, > QemuOpts *opts, > return ret; > } > > > > +#ifdef __APPLE__ > + > +static int cdrom_is_inserted(BlockDriverState *bs) > +{ > + static int count = 0; > + int returnValue = 1; > + > + if(count == 0) { > + returnValue = 0; // get around find_image_format() issue > + } > + > + printf("count = %d for %s, returning %d\n", count, bs->filename, > returnValue); > + count++; > + return returnValue; > +} > +#endif So instead, read the size of the device, if it is 0, return false. Something like for FreeBSD. raw_getlength(bs), and raw_getlength() should use an ioctl() to get the size. I think you can use something like DKIOCGETBLOCKCOUNT. http://www.opensource.apple.com/source/xnu/xnu-1456.1.26/bsd/sys/disk.h https://developer.apple.com/library/mac/samplecode/CDROMSample/Listings/CDROMSample_CDROMSample_c.html > static BlockDriver bdrv_host_device = { > .format_name = "host_device", > .protocol_name = "host_device", > @@ -2365,6 +2382,10 @@ static BlockDriver bdrv_host_device = { > .bdrv_ioctl = hdev_ioctl, > .bdrv_aio_ioctl = hdev_aio_ioctl, > #endif > + > +#ifdef __APPLE__ > + .bdrv_is_inserted = cdrom_is_inserted, > +#endif > }; We need also cdrom_eject, and cdrom_lock_medium. This example can help: http://www.opensource.apple.com/source/DiskArbitration/DiskArbitration-156/disktool/disktool.c Laurent