Re: [Qemu-devel] [PATCH v2 4/5] console: pass Monitor to vga_hw_screen_dump/hw_vga_dump

[Luiz Capitulino <lcapitulino@redhat.com>]

On Wed, 14 Mar 2012 08:37:13 +0000
"Daniel P. Berrange" <berrange@redhat.com> wrote:

> > First, with this applied you will not know the size in advance.  Also
> > one of the approaches discussed is to allow passing in a file handle.
> > That is a possible way to handle async screendumps too: just write to
> > the passed file handle and close it when done.  Obvious drawback is that
> > this will not cover the classic way of specifying the output filename as
> > argument.

As Daniel explains below, this is not a drawback and there's no problem
supporting multiple ways of returning the image.

The real drawback of making this w/o async support is that you can't detect
errors.

> This would not be a problem from libvirt's POV - we don't really want a
> file on disk anyway, nor do we want to pull the whole image into memory.
> Our ideal approach is to just have an pipe FD with QEMU, which we just
> incrementally read image data from, and forward to the client app via
> a libvirt stream object.