[PATCH v3 1/2] server: prevent division by zero in coordinate mapping

[Wei Xie]

From: Wei Xie

Wine applications crash in VNC/headless environments due to invalid all-zero monitor coordinates.

The root cause is:
Environment Issue: VNC systems report all displays as RR_Disconnected
Faulty Fallback: Wine incorrectly reverts to legacy XRandR 1.0 API when no "connected" displays are detected
API Incompatibility: Modern XRandR 1.6 doesn't support Wine's XRandR 1.0 implementation, causing XRRSizes() to return empty display modes
Uninitialized Data: This leaves critical display fields (dmPelsWidth/Height) at initialization value 0
---
 server/window.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/server/window.c b/server/window.c
index c59b8646118..8d75482940d 100644
--- a/server/window.c
+++ b/server/window.c
@@ -315,6 +315,8 @@ static void map_point_raw_to_virt( struct desktop *desktop, int *x, int *y )
     width_from = monitor->raw.right - monitor->raw.left;
     height_from = monitor->raw.bottom - monitor->raw.top;

+    if (width_from == 0 || height_from == 0) return;
+
     *x = *x * 2 - (monitor->raw.left * 2 + width_from);
     *x = (*x * width_to * 2 + width_from) / (width_from * 2);
     *x = (*x + monitor->virt.left * 2 + width_to) / 2;