On Tue, Apr 12, 2011 at 10:10:44AM +0200, Kevin Wolf wrote: > Am 12.04.2011 09:52, schrieb Daniel P. Berrange: > > - If the -drive specification has readonly=on (thus O_RDONLY to > > open(2) call) , I expect QEMU (or the kernel) to forbid the > > "eject" command on the host CDROM. This should prevent two guests > > interfering seriously with each other. > > > > So I think using O_EXCL would be OK, in the case where the block > > driver was host_cdrom and readonly=off. > > This would overload readonly with a completely unrelated option (should > eject be allowed). Doesn't sound like a great idea.
Use of the "host_cdrom" block driver enables passthrough of commands to the host device. Use of "readonly" is what controls whether individual passthrough commands are actually permitted. To me, "readonly" means don't allow anything that would impact another guests view of the file/device. So forbidding 'eject' is within scope of that IMHO. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
