[PATCH 2/2] vbox: Fix starting domains

[Michal Prívozník]

On 1/23/23 10:45, Martin Kletzander wrote:
> 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 While the whole algorithm looks a bit outdated, it may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 at redhat.com>
>> ---
>> 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.

I'm failing to see how guiPresent and sdlPresent can be set at the same
time. But I guess I can join those two cases together, sure.

Michal