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authorGerd Hoffmann <kraxel@redhat.com>2018-03-08 17:18:03 +0100
committerGerd Hoffmann <kraxel@redhat.com>2018-03-12 09:00:59 +0100
commit2e5567c903ad05d312de0c3188cb2d3b856fa4c4 (patch)
tree1b6a308596eb1d796a58fcae729f3ac8f58c45b0 /ui
parentf1bd313264925dfb229a2152eb3f60fe55746b83 (diff)
vnc: deal with surface NULL pointers
Secondary displays in multihead setups are allowed to have a NULL DisplaySurface. Typically user interfaces handle this by hiding the window which shows the display in question. This isn't an option for vnc though because it simply hasn't a concept of windows or outputs. So handle the situation by showing a placeholder DisplaySurface instead. Also check in console_select whenever a surface is preset in the first place before requesting an update. This fixes a segfault which can be triggered by switching to an unused display (via vtrl-alt-<nr>) in a multihead setup, for example using -device virtio-vga,max_outputs=2. Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Message-id: 20180308161803.6152-1-kraxel@redhat.com
Diffstat (limited to 'ui')
-rw-r--r--ui/console.c10
-rw-r--r--ui/vnc.c10
2 files changed, 16 insertions, 4 deletions
diff --git a/ui/console.c b/ui/console.c
index 6ab4ff3baf..348610dd43 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1039,8 +1039,10 @@ void console_select(unsigned int index)
dcl->ops->dpy_gfx_switch(dcl, s->surface);
}
}
- dpy_gfx_update(s, 0, 0, surface_width(s->surface),
- surface_height(s->surface));
+ if (s->surface) {
+ dpy_gfx_update(s, 0, 0, surface_width(s->surface),
+ surface_height(s->surface));
+ }
}
if (ds->have_text) {
dpy_text_resize(s, s->width, s->height);
@@ -1370,8 +1372,8 @@ DisplaySurface *qemu_create_displaysurface_guestmem(int width, int height,
return surface;
}
-static DisplaySurface *qemu_create_message_surface(int w, int h,
- const char *msg)
+DisplaySurface *qemu_create_message_surface(int w, int h,
+ const char *msg)
{
DisplaySurface *surface = qemu_create_displaysurface(w, h);
pixman_color_t bg = color_table_rgb[0][QEMU_COLOR_BLACK];
diff --git a/ui/vnc.c b/ui/vnc.c
index 13c28cabb0..e164eb798c 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -746,9 +746,19 @@ static void vnc_update_server_surface(VncDisplay *vd)
static void vnc_dpy_switch(DisplayChangeListener *dcl,
DisplaySurface *surface)
{
+ static const char placeholder_msg[] =
+ "Display output is not active.";
+ static DisplaySurface *placeholder;
VncDisplay *vd = container_of(dcl, VncDisplay, dcl);
VncState *vs;
+ if (surface == NULL) {
+ if (placeholder == NULL) {
+ placeholder = qemu_create_message_surface(640, 480, placeholder_msg);
+ }
+ surface = placeholder;
+ }
+
vnc_abort_display_jobs(vd);
vd->ds = surface;