annotate src/events/SDL_expose.c @ 4158:96ce26f24b01 SDL-1.2

Date: Sun, 7 Sep 2008 15:17:00 +0200 From: c2woody@gmx.net Subject: [SDL] SDL 1.2 doube free/pointer zeroing missing Hello, this is about a crash/debug breakage for the current SDL 1.2 source tree (today's svn checkout, same problem in 1.2.13 and before as far as relevant). In some places memory is free()d but the associated pointer is not zeroed, leading to for example double free()s. For me this happened because SDL_StopEventThread() was executed twice (during restart of the subsystems), once for the close down in SDL_VideoQuit() and once at the startup, right at the beginning of SDL_StartEventLoop(). Thus the code SDL_DestroyMutex(SDL_EventQ.lock); (see SDL_events.c) was called twice and executed the SDL_free(mutex); twice as well, leading to a crash (msvc 64bit for which it was noticed). I've tried to check all other occurrences of SDL_free and similar code in msvc, see the attached patch (udiff against revision 4082). Non-windows only codepaths have neither been checked nor touched. Comments/ideas welcome. Attached patch: NULLifies some pointers after they have been free()d.
author Sam Lantinga <slouken@libsdl.org>
date Wed, 12 Nov 2008 17:23:40 +0000
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997-2006 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Lesser General Public
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7 License as published by the Free Software Foundation; either
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8 version 2.1 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Lesser General Public License for more details.
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14
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15 You should have received a copy of the GNU Lesser General Public
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16 License along with this library; if not, write to the Free Software
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17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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19 Sam Lantinga
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20 slouken@libsdl.org
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21 */
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22 #include "SDL_config.h"
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23
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24 /* Refresh event handling code for SDL */
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25
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26 #include "SDL_events.h"
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27 #include "SDL_events_c.h"
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28
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29
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30 /* This is global for SDL_eventloop.c */
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31 int SDL_PrivateExpose(void)
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32 {
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33 int posted;
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34 SDL_Event events[32];
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35
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36 /* Pull out all old refresh events */
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37 SDL_PeepEvents(events, sizeof(events)/sizeof(events[0]),
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38 SDL_GETEVENT, SDL_VIDEOEXPOSEMASK);
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39
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40 /* Post the event, if desired */
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41 posted = 0;
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42 if ( SDL_ProcessEvents[SDL_VIDEOEXPOSE] == SDL_ENABLE ) {
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43 SDL_Event event;
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44 event.type = SDL_VIDEOEXPOSE;
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45 if ( (SDL_EventOK == NULL) || (*SDL_EventOK)(&event) ) {
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46 posted = 1;
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47 SDL_PushEvent(&event);
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48 }
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49 }
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50 return(posted);
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51 }