Re: qemu-sockets: account for trailing \0 byte in unix socket pathname

[Daniel P . Berrangé]

On Tue, Aug 31, 2021 at 08:47:43PM +0300, Michael Tokarev wrote:
> 31.08.2021 20:38, Daniel P. Berrangé wrote:
> ...
> > > > So it looks like libvirt provides an unnamed socket there, --
> > > > maybe from a socketpair(2)?
> > > > 
> > > 
> > > Yes
> > 
> > No, libvirt binds to a named socket path and passes in a pre-opened
> > FD for the listener socket. There shouldn't be any socketpair involved.
> 
> Here's some more info from the original bugreport:
> 
> 31.08.2021 00:20, dann frazier wrote:
> > Aha! It seems that the important difference is whether or not the
> > virt-manager GUI window for the VM is active. If it is active, the VM
> > crashes regardless of how it is started (virsh console start/clicking
> > "play" button). If the GUI is not active, the VM always works.
> >
> > With this knowledge I am able to confidently say that reverting
> > 4cfd970ec1 *does* reliably avoid the problem.
> 
> We'll try to figure out the calltrace, where this socket is coming from..

Oh, it is probably from the graphical console connection to SPICE or VNC.
For those virt-manager will pass in a socket creted with socketpair()
via libvirt, in order to bypass the need for authentication when running
locally.

Regards,
Daniel
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