Rework composite overlay window code to fix several resource management bugs.

The composite overlay window code had several misunderstandings of the workings of the X server, in particular error handling paths would often double-free objects. Clean all of this up by using resource destruction as the sole mechanism for freeing resource-based objects.
2026-03-24 05:54:08 +00:00 · 2008-05-04 21:52:58 -07:00
parent 6c1accce87
commit efa65a0317
5 changed files with 206 additions and 184 deletions
--- a/composite/compoverlay.c
+++ b/composite/compoverlay.c
@@ -0,0 +1,159 @@
+/*
+ * Copyright © 2006 Sun Microsystems
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Sun Microsystems not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission.  Sun Microsystems makes no
+ * representations about the suitability of this software for any purpose.  It
+ * is provided "as is" without express or implied warranty.
+ *
+ * SUN MICROSYSTEMS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL SUN MICROSYSTEMS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Copyright © 2003 Keith Packard
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation, and that the name of Keith Packard not be used in
+ * advertising or publicity pertaining to distribution of the software without
+ * specific, written prior permission.  Keith Packard makes no
+ * representations about the suitability of this software for any purpose.  It
+ * is provided "as is" without express or implied warranty.
+ *
+ * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif
+
+#include "compint.h"
+#include "xace.h"
+
+/* 
+ * Delete the given overlay client list element from its screen list.
+ */
+void
+compFreeOverlayClient (CompOverlayClientPtr pOcToDel)
+{
+    ScreenPtr		    pScreen = pOcToDel->pScreen;
+    CompScreenPtr	    cs = GetCompScreen (pScreen);
+    CompOverlayClientPtr    *pPrev, pOc;
+
+    for (pPrev = &cs->pOverlayClients; (pOc = *pPrev); pPrev = &pOc->pNext)
+    {
+	if (pOc == pOcToDel) {
+	    *pPrev = pOc->pNext;
+	    xfree (pOc);
+	    break;
+	}
+    }
+    
+    /* Destroy overlay window when there are no more clients using it */
+    if (cs->pOverlayClients == NULL)
+	compDestroyOverlayWindow (pScreen);
+}
+
+/*
+ * Return the client's first overlay client rec from the given screen
+ */
+CompOverlayClientPtr
+compFindOverlayClient (ScreenPtr pScreen, ClientPtr pClient)
+{
+    CompScreenPtr	    cs = GetCompScreen(pScreen);
+    CompOverlayClientPtr    pOc;
+
+    for (pOc = cs->pOverlayClients; pOc != NULL; pOc = pOc->pNext)
+	if (pOc->pClient == pClient)
+	    return pOc;
+
+    return NULL;           
+}
+
+/*
+ * Create an overlay client object for the given client
+ */
+CompOverlayClientPtr
+compCreateOverlayClient (ScreenPtr pScreen, ClientPtr pClient)
+{
+    CompScreenPtr    cs = GetCompScreen(pScreen);
+    CompOverlayClientPtr pOc;
+
+    pOc = (CompOverlayClientPtr) xalloc(sizeof(CompOverlayClientRec));
+    if (pOc == NULL)
+	return NULL;
+
+    pOc->pClient = pClient;
+    pOc->pScreen = pScreen;
+    pOc->resource = FakeClientID(pClient->index);
+    pOc->pNext = cs->pOverlayClients;
+    cs->pOverlayClients = pOc;
+
+    /* 
+     * Create a resource for this element so it can be deleted
+     * when the client goes away.
+     */
+    if (!AddResource (pOc->resource, CompositeClientOverlayType, (pointer) pOc))
+	return NULL;
+
+    return pOc;
+}
+
+/*
+ * Create the overlay window and map it
+ */
+Bool
+compCreateOverlayWindow (ScreenPtr pScreen)
+{
+    CompScreenPtr   cs = GetCompScreen(pScreen);
+    WindowPtr	    pRoot = WindowTable[pScreen->myNum];
+    WindowPtr	    pWin;
+    XID		    overrideRedirect = TRUE;
+    int		    result;
+
+    pWin = cs->pOverlayWin = 
+	CreateWindow (cs->overlayWid, pRoot,
+		      0, 0, pScreen->width, pScreen->height, 0, 
+		      InputOutput, CWOverrideRedirect, &overrideRedirect,
+		      pRoot->drawable.depth, 
+		      serverClient, pScreen->rootVisual, &result);
+    if (pWin == NULL)
+	return FALSE;
+
+    if (!AddResource(pWin->drawable.id, RT_WINDOW, (pointer)pWin))
+	return FALSE;
+
+    MapWindow(pWin, serverClient);
+
+    return TRUE;
+}
+
+/*
+ * Destroy the overlay window
+ */
+void
+compDestroyOverlayWindow (ScreenPtr pScreen)
+{
+    CompScreenPtr cs = GetCompScreen(pScreen);
+
+    cs->pOverlayWin = NullWindow;
+    FreeResource (cs->overlayWid, RT_NONE);
+}
+