Re: [libvirt] [PATCH] qemu: Avoid crashes in qemuDomainMachineIs*()

On Tue, Oct 10, 2017 at 04:21:02PM +0200, Andrea Bolognani wrote: Hmm, I don't think that is a good fix for the problem seen there. We're parsing the CLI argv from an existing QEMU process and when looking at the disk we're checking if the machine type refers to a pseries guest. The problem is that either the user might not have given any -machine arg, or the -drive arg might occur *before* the -machine arg is parsed. Simply making the qemuDomainMachineIs* safe against NULL will avoid the crash, but the ARGV parsing is still going to be semantically broken. As a more general point, we've tended to assume that machine is always non-NULL throughout the code, because we rely on the XML parsing to fill in defaults if omitted by the user. I think rather than trying to fix up the assumption about machine being non-NULL, we should restructure the ARGV parsing into we need a 2 pass process. In the first pass only look for the -machine arg. If no -machine arg is given, we should fill in the default machine for that emulator. In the second pass process the rest of the ARGV, whereupon we have a valid assumption that machine is non-NULL. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|