XQuartz: RandR: Don't crash if X11 is launched while there are no attached displays

If CG reports no displays when launching, we could crash in RandR.  Instead, just
provide a fake 800x600 display until we are notified about displays being attached.

Signed-off-by: Jeremy Huddleston <jeremyhu@apple.com>

hw/xquartz/quartz.c

@@ -464,11 +464,15 @@ void QuartzSpaceChanged(uint32_t space_id) {
 void QuartzCopyDisplayIDs(ScreenPtr pScreen,
                           int displayCount, CGDirectDisplayID *displayIDs) {
     QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
-    int size = displayCount * sizeof(CGDirectDisplayID);
 
     free(pQuartzScreen->displayIDs);
+    if(displayCount) {
+        size_t size = displayCount * sizeof(CGDirectDisplayID);
         pQuartzScreen->displayIDs = malloc(size);
         memcpy(pQuartzScreen->displayIDs, displayIDs, size);
+    } else {
+       pQuartzScreen->displayIDs = NULL;
+    }
     pQuartzScreen->displayCount = displayCount;
 }
 

hw/xquartz/quartzRandR.c

@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2001-2004 Greg Parker and Torrey T. Lyons,
  *               2010      Jan Hauffa.
- *               2010      Apple Inc.
+ *               2010-2011 Apple Inc.
  *                 All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
@@ -124,13 +124,16 @@ static Bool QuartzRandRSetCGMode (CGDirectDisplayID screenId,
 static Bool QuartzRandREnumerateModes (ScreenPtr pScreen,
                                        QuartzModeCallback callback,
                                        void *data) {
+    Bool retval = FALSE;
+    QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
+
+    /* Just an 800x600 fallback if we have no attached heads */
+    if(pQuartzScreen->displayIDs) {
         CFDictionaryRef curModeRef, modeRef;
         long curBpp;
         CFArrayRef modes;
         QuartzModeInfo modeInfo;
         int i;
-    BOOL retval = FALSE;
-    QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
         CGDirectDisplayID screenId = pQuartzScreen->displayIDs[0];
 
         curModeRef = CGDisplayCurrentMode(screenId);
@@ -163,6 +166,7 @@ static Bool QuartzRandREnumerateModes (ScreenPtr pScreen,
             else if (cb == CALLBACK_ERROR)
                 return FALSE;
         }
+    }
 
     switch(callback(pScreen, &pQuartzScreen->rootlessMode, data)) {
         case CALLBACK_SUCCESS:
@@ -225,15 +229,17 @@ static Bool QuartzRandRSetCGMode (CGDirectDisplayID screenId,
 static Bool QuartzRandREnumerateModes (ScreenPtr pScreen,
                                        QuartzModeCallback callback,
                                        void *data) {
+    Bool retval = FALSE;
+    QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
+
+    /* Just an 800x600 fallback if we have no attached heads */
+    if(pQuartzScreen->displayIDs) {
         CGDisplayModeRef curModeRef, modeRef;
         CFStringRef curPixelEnc, pixelEnc;
         CFComparisonResult pixelEncEqual;
         CFArrayRef modes;
         QuartzModeInfo modeInfo;
         int i;
-    Bool retval = FALSE;
-
-    QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
         CGDirectDisplayID screenId = pQuartzScreen->displayIDs[0];
 
         curModeRef = CGDisplayCopyDisplayMode(screenId);
@@ -280,6 +286,7 @@ static Bool QuartzRandREnumerateModes (ScreenPtr pScreen,
 
         CFRelease(modes);
         CFRelease(curPixelEnc);
+    }
 
     switch(callback(pScreen, &pQuartzScreen->rootlessMode, data)) {
         case CALLBACK_SUCCESS:
@@ -347,9 +354,13 @@ static int QuartzRandRRegisterModeCallback (ScreenPtr pScreen,
 
 static Bool QuartzRandRSetMode(ScreenPtr pScreen, QuartzModeInfoPtr pMode, BOOL doRegister) {
     QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
-    CGDirectDisplayID screenId = pQuartzScreen->displayIDs[0];
     Bool captureDisplay = (pMode->refresh != FAKE_REFRESH_FULLSCREEN && pMode->refresh != FAKE_REFRESH_ROOTLESS);
+    CGDirectDisplayID screenId;
 
+    if(pQuartzScreen->displayIDs == NULL)
+        return FALSE;
+
+    screenId = pQuartzScreen->displayIDs[0];
     if(XQuartzShieldingWindowLevel == 0 && captureDisplay) {
         if(!X11ApplicationCanEnterRandR())
             return FALSE;
@@ -379,6 +390,7 @@ static Bool QuartzRandRSetMode(ScreenPtr pScreen, QuartzModeInfoPtr pMode, BOOL
     if(pQuartzScreen->currentMode.ref)
         CFRelease(pQuartzScreen->currentMode.ref);
     pQuartzScreen->currentMode = *pMode;
+    if(pQuartzScreen->currentMode.ref)
         CFRetain(pQuartzScreen->currentMode.ref);
     
     if(XQuartzShieldingWindowLevel != 0 && !captureDisplay) {
@@ -406,13 +418,8 @@ static int QuartzRandRSetModeCallback (ScreenPtr pScreen,
 }
 
 static Bool QuartzRandRGetInfo (ScreenPtr pScreen, Rotation *rotations) {
-    QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
-
     *rotations = RR_Rotate_0;  /* TODO: support rotation */
 
-    if (pQuartzScreen->displayCount == 0)
-        return FALSE;
-
     return QuartzRandREnumerateModes(pScreen, QuartzRandRRegisterModeCallback, NULL);
 }
 
@@ -427,9 +434,6 @@ static Bool QuartzRandRSetConfig (ScreenPtr           pScreen,
     reqMode.height = pSize->height;
     reqMode.refresh = rate;
 
-    if (pQuartzScreen->displayCount == 0)
-        return FALSE;
-
     /* Do not switch modes if requested mode is equal to current mode. */
     if (QuartzRandRModesEqual(&reqMode, &pQuartzScreen->currentMode))
         return TRUE;
@@ -446,17 +450,24 @@ static Bool _QuartzRandRUpdateFakeModes (ScreenPtr pScreen) {
     QuartzScreenPtr pQuartzScreen = QUARTZ_PRIV(pScreen);
     QuartzModeInfo activeMode;
 
-    if (!QuartzRandRCopyCurrentModeInfo(pQuartzScreen->displayIDs[0], &activeMode)) {
+    if(pQuartzScreen->displayCount > 0) {
+        if(!QuartzRandRCopyCurrentModeInfo(pQuartzScreen->displayIDs[0], &activeMode)) {
             ErrorF("Unable to determine current display mode.\n");
             return FALSE;
         }
+    } else {
+        memset(&activeMode, 0, sizeof(activeMode));
+        activeMode.width = 800;
+        activeMode.height = 600;
+        activeMode.refresh = 60;
+    }
 
     if(pQuartzScreen->fullscreenMode.ref)
         CFRelease(pQuartzScreen->fullscreenMode.ref);
     if(pQuartzScreen->currentMode.ref)
         CFRelease(pQuartzScreen->currentMode.ref);
 
-    if (pQuartzScreen->displayCount > 1) {
+    if(pQuartzScreen->displayCount > 1) {
         activeMode.width = pScreen->width;
         activeMode.height = pScreen->height;
         if(XQuartzIsRootless)
@@ -479,6 +490,7 @@ static Bool _QuartzRandRUpdateFakeModes (ScreenPtr pScreen) {
     /* This extra retain is for currentMode's copy.
      * fullscreen and rootless share a retain.
      */
+    if(pQuartzScreen->currentMode.ref)
         CFRetain(pQuartzScreen->currentMode.ref);
     
     DEBUG_LOG("rootlessMode: %d x %d\n", (int)pQuartzScreen->rootlessMode.width, (int)pQuartzScreen->rootlessMode.height);

hw/xquartz/xpr/xprScreen.c

@@ -193,6 +193,7 @@ xprAddPseudoramiXScreens(int *x, int *y, int *width, int *height, ScreenPtr pScr
         *width = 800;
         *height = 600;
         PseudoramiXAddScreen(*x, *y, *width, *height);
+        QuartzCopyDisplayIDs(pScreen, 0, NULL);
         return;
     }