Re: [PATCH 2/2] vbox: Fix starting domains

On Mon, Jan 23, 2023 at 10:31:53AM +0100, Michal Privoznik wrote: > When starting a VirtualBox domain, we try to guess which frontend > to use. While the whole algorithm looks a bit outdated, it may > happen that we tell VirtualBox to use "gui" frontend, but not > which DISPLAY= to use. > > I haven't found any documentation on the algorithm we use, but if > I make us fallback onto DISPLAY=:0 when no other configuration is > found then I'm able to start my guests just fine. > > Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; > --- > src/vbox/vbox_common.c | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/src/vbox/vbox_common.c b/src/vbox/vbox_common.c > index bd77641d39..5269f9b23f 100644 > --- a/src/vbox/vbox_common.c > +++ b/src/vbox/vbox_common.c > @@ -2121,13 +2121,12 @@ vboxStartMachine(virDomainPtr dom, int > maxDomID, IMachine *machine, vboxIID *iid >     VBOX_UTF8_FREE(valueDisplayUtf8); > >     if (guiPresent) { > -        if (guiDisplay) { > -            char *displayutf8; > -            displayutf8 = g_strdup_printf("DISPLAY=%s", guiDisplay); > -            VBOX_UTF8_TO_UTF16(displayutf8, &env); > -            VIR_FREE(displayutf8); > -            VIR_FREE(guiDisplay); > -        } > +        char *displayutf8; > + > +        displayutf8 = g_strdup_printf("DISPLAY=%s", guiDisplay ? > guiDisplay : ":0"); > +        VBOX_UTF8_TO_UTF16(displayutf8, &env); This might get overwritten when using SDL couple lines below.  I suggest you default to :0 only if none other option remains.  It feels dirty just guessing the display number, but let's say that's something we'll have to live with in the vbox driver.