[Stable-7.2.6 61/63] ui: fix crash when there are no active_console

[Michael Tokarev]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Thread 1 "qemu-system-x86" received signal SIGSEGV, Segmentation fault.
0x0000555555888630 in dpy_ui_info_supported (con=0x0) at ../ui/console.c:812
812         return con->hw_ops->ui_info != NULL;
(gdb) bt
#0  0x0000555555888630 in dpy_ui_info_supported (con=0x0) at ../ui/console.c:812
#1  0x00005555558a44b1 in protocol_client_msg (vs=0x5555578c76c0, 
data=0x5555581e93f0 <incomplete sequence \373>, len=24) at ../ui/vnc.c:2585
#2  0x00005555558a19ac in vnc_client_read (vs=0x5555578c76c0) at 
../ui/vnc.c:1607
#3  0x00005555558a1ac2 in vnc_client_io (ioc=0x5555581eb0e0, condition=G_IO_IN, 
opaque=0x5555578c76c0) at ../ui/vnc.c:1635

Fixes:
https://issues.redhat.com/browse/RHEL-2600

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Albert Esteve <aesteve@redhat.com>
(cherry picked from commit 48a35e12faf90a896c5aa4755812201e00d60316)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/ui/console.c b/ui/console.c
index 646202214a..52414d6aa3 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1697,6 +1697,9 @@ bool dpy_ui_info_supported(QemuConsole *con)
     if (con == NULL) {
         con = active_console;
     }
+    if (con == NULL) {
+        return false;
+    }
 
     return con->hw_ops->ui_info != NULL;
 }
-- 
2.39.2