Add error handler to catch back-end X errors -- fixes xtest crashes

2 files changed, 27 insertions, 0 deletions

diff --git a/xc/programs/Xserver/hw/dmx/dmx.h b/xc/programs/Xserver/hw/dmx/dmx.h
index db7531502..272dd4e19 100644
--- a/xc/programs/Xserver/hw/dmx/dmx.h
+++ b/xc/programs/Xserver/hw/dmx/dmx.h
@@ -150,6 +150,8 @@ typedef struct _DMXInputInfo DMXInputInfo;
 extern int              dmxNumScreens;
 extern DMXScreenInfo   *dmxScreens;
 extern int              dmxShadowFB;
+extern XErrorEvent      dmxLastErrorEvent;
+extern Bool             dmxErrorOccurred;
 
 #define DMX_WRAP(_entry, _newfunc, _saved, _actual)			\
 do {									\
diff --git a/xc/programs/Xserver/hw/dmx/dmxinit.c b/xc/programs/Xserver/hw/dmx/dmxinit.c
index a1f14421c..ed92d862b 100644
--- a/xc/programs/Xserver/hw/dmx/dmxinit.c
+++ b/xc/programs/Xserver/hw/dmx/dmxinit.c
@@ -58,6 +58,25 @@ DMXInputInfo   *dmxInputs;
 
 int             dmxShadowFB = TRUE;
 
+XErrorEvent     dmxLastErrorEvent;
+Bool            dmxErrorOccurred = FALSE;
+
+/* dmxErrorHandler catches errors that occur when calling one of the
+ * back-end servers. */
+static int dmxErrorHandler(Display *dpy, XErrorEvent *ev)
+{
+#define DMX_ERROR_BUF_SIZE 256
+    char  buf[DMX_ERROR_BUF_SIZE];
+
+    dmxErrorOccurred  = TRUE;
+    dmxLastErrorEvent = *ev;
+
+    XGetErrorText(dpy, ev->error_code, buf, DMX_ERROR_BUF_SIZE);
+    dmxLog(dmxWarning, "dmxErrorHandler: %s\n", buf);
+
+    return 0;
+}
+
 /* dmxAddInputName adds a display name to the dmxScreens
  * structure. Note: can't use xalloc/xfree here because OsInit() hasn't
  * been called yet.  Use malloc/free instead.  See also
@@ -112,6 +131,11 @@ static void dmxOpenDisplay(DMXScreenInfo *dmxScreen)
                dmxScreen->name);
 }
 
+static void dmxSetErrorHandler(DMXScreenInfo *dmxScreen)
+{
+    XSetErrorHandler(dmxErrorHandler);
+}
+
 static void dmxPrintScreenInfo(DMXScreenInfo *dmxScreen)
 {
     XWindowAttributes attribs;
@@ -333,6 +357,7 @@ static void dmxDisplayInit(ScreenInfo *pScreenInfo, DMXScreenInfo *dmxScreen,
 		    int argc, char *charv[])
 {
     dmxOpenDisplay(dmxScreen);
+    dmxSetErrorHandler(dmxScreen);
     dmxCheckForWM(dmxScreen);
     dmxGetScreenAttribs(dmxScreen);
     dmxGetVisualInfo(dmxScreen);