Mercurial > sdl-ios-xcode
annotate src/thread/win32/SDL_syssem.c @ 1176:dd2a8deeb26d
Date: Mon, 17 Oct 2005 20:09:03 -0400
From: Mark Schreiber <mark7@alumni.cmu.edu>
To: ryan@clutteredmind.org
Subject: [PATCH]SDL mprotect() crash fix
(I'm going to throw this patch your way at the suggestion of #SDL --
for some reason, I had some difficulty sending it to the main list
last time, and I go bonkers subscribing to send each email or
patch...)
Currently, when I run SDL applications as non-root using
SDL_VIDEODRIVER=dga, the fbdev fallback mprotect()s read/write the
proper size of mmapped /dev/fb0 (7.5MB), but on framebuffer release
mprotect()s read-only the range by the entire size of my video memory
(128MB), which causes a segfault:
#0 0x002a9a27 in ?? () from /lib/libc.so.6
#1 0x04a63eb6 in SDL_XDGAUnmapFramebuffer (screen=3D0) at XF86DGA2.c:978
#2 0x04a63efc in SDL_XDGACloseFramebuffer (dpy=3D0x9d3f008, screen=3D0)
at XF86DGA2.c:268
#3 0x04a68b57 in DGA_Available () at SDL_dgavideo.c:98
#4 0x04a53677 in SDL_VideoInit (driver_name=3D0xbfb0bfc7 "dga", flags=3D0)
at SDL_video.c:180
#5 0x04a2613f in SDL_InitSubSystem (flags=3D32) at SDL.c:74
#6 0x04a2617c in SDL_Init (flags=3D32) at SDL.c:166
#7 0x08049722 in main (argc=3D1, argv=3D0x0) at testwin.c:32
This is SDL 1.2.8 on Fedora Core 4, radeon driver for a Radeon 9250,
xorg-x11-6.8.2-37.
I've attached a one-line patch against SDL CVS that updates the size
of the framebuffer at framebuffer map time so that the mprotect() on
unmap will be the same size. I'm not sure if this is the best
approach (i.e. one might want to retain the original value), but it
does make my SDL applications work without segfaulting.
-- Best of luck, Mark Schreiber
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Sat, 19 Nov 2005 18:57:00 +0000 |
| parents | b8d311d90021 |
| children | c9b51268668f |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
|
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Updated copyright information for 2004 (Happy New Year!)
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3 Copyright (C) 1997-2004 Sam Lantinga |
| 0 | 4 |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 of the License, or (at your option) any later version. | |
| 9 | |
| 10 This library is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
|
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20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 #ifdef SAVE_RCSID | |
| 24 static char rcsid = | |
| 25 "@(#) $Id$"; | |
| 26 #endif | |
| 27 | |
| 28 /* Semaphore functions using the Win32 API */ | |
| 29 | |
| 30 #include <stdio.h> | |
| 31 #include <stdlib.h> | |
| 32 #include <windows.h> | |
| 33 | |
| 34 #include "SDL_error.h" | |
| 35 #include "SDL_thread.h" | |
| 36 #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) | |
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37 #include "win_ce_semaphore.h" |
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38 #endif |
| 0 | 39 |
| 40 | |
| 41 struct SDL_semaphore { | |
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42 #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
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43 SYNCHHANDLE id; |
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44 #else |
| 0 | 45 HANDLE id; |
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46 #endif |
| 0 | 47 Uint32 volatile count; |
| 48 }; | |
| 49 | |
| 50 | |
| 51 /* Create a semaphore */ | |
| 52 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 53 { | |
| 54 SDL_sem *sem; | |
| 55 | |
| 56 /* Allocate sem memory */ | |
| 57 sem = (SDL_sem *)malloc(sizeof(*sem)); | |
| 58 if ( sem ) { | |
| 59 /* Create the semaphore, with max value 32K */ | |
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60 #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
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61 sem->id = CreateSemaphoreCE(NULL, initial_value, 32*1024, NULL); |
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62 #else |
| 0 | 63 sem->id = CreateSemaphore(NULL, initial_value, 32*1024, NULL); |
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64 #endif |
| 0 | 65 sem->count = initial_value; |
| 66 if ( ! sem->id ) { | |
| 67 SDL_SetError("Couldn't create semaphore"); | |
| 68 free(sem); | |
| 69 sem = NULL; | |
| 70 } | |
| 71 } else { | |
| 72 SDL_OutOfMemory(); | |
| 73 } | |
| 74 return(sem); | |
| 75 } | |
| 76 | |
| 77 /* Free the semaphore */ | |
| 78 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 79 { | |
| 80 if ( sem ) { | |
| 81 if ( sem->id ) { | |
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82 #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
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83 CloseSynchHandle(sem->id); |
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84 #else |
| 0 | 85 CloseHandle(sem->id); |
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86 #endif |
| 0 | 87 sem->id = 0; |
| 88 } | |
| 89 free(sem); | |
| 90 } | |
| 91 } | |
| 92 | |
| 93 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 94 { | |
| 95 int retval; | |
| 96 DWORD dwMilliseconds; | |
| 97 | |
| 98 if ( ! sem ) { | |
| 99 SDL_SetError("Passed a NULL sem"); | |
| 100 return -1; | |
| 101 } | |
| 102 | |
| 103 if ( timeout == SDL_MUTEX_MAXWAIT ) { | |
| 104 dwMilliseconds = INFINITE; | |
| 105 } else { | |
| 106 dwMilliseconds = (DWORD)timeout; | |
| 107 } | |
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108 #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
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109 switch (WaitForSemaphoreCE(sem->id, dwMilliseconds)) { |
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110 #else |
| 0 | 111 switch (WaitForSingleObject(sem->id, dwMilliseconds)) { |
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112 #endif |
| 0 | 113 case WAIT_OBJECT_0: |
| 114 --sem->count; | |
| 115 retval = 0; | |
| 116 break; | |
| 117 case WAIT_TIMEOUT: | |
| 118 retval = SDL_MUTEX_TIMEDOUT; | |
| 119 break; | |
| 120 default: | |
| 121 SDL_SetError("WaitForSingleObject() failed"); | |
| 122 retval = -1; | |
| 123 break; | |
| 124 } | |
| 125 return retval; | |
| 126 } | |
| 127 | |
| 128 int SDL_SemTryWait(SDL_sem *sem) | |
| 129 { | |
| 130 return SDL_SemWaitTimeout(sem, 0); | |
| 131 } | |
| 132 | |
| 133 int SDL_SemWait(SDL_sem *sem) | |
| 134 { | |
| 135 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); | |
| 136 } | |
| 137 | |
| 138 /* Returns the current count of the semaphore */ | |
| 139 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 140 { | |
| 141 if ( ! sem ) { | |
| 142 SDL_SetError("Passed a NULL sem"); | |
| 143 return 0; | |
| 144 } | |
| 145 return sem->count; | |
| 146 } | |
| 147 | |
| 148 int SDL_SemPost(SDL_sem *sem) | |
| 149 { | |
| 150 if ( ! sem ) { | |
| 151 SDL_SetError("Passed a NULL sem"); | |
| 152 return -1; | |
| 153 } | |
| 154 /* Increase the counter in the first place, because | |
| 155 * after a successful release the semaphore may | |
| 156 * immediately get destroyed by another thread which | |
| 157 * is waiting for this semaphore. | |
| 158 */ | |
| 159 ++sem->count; | |
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160 #if defined(_WIN32_WCE) && (_WIN32_WCE < 300) |
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161 if ( ReleaseSemaphoreCE(sem->id, 1, NULL) == FALSE ) { |
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162 #else |
| 0 | 163 if ( ReleaseSemaphore(sem->id, 1, NULL) == FALSE ) { |
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164 #endif |
| 0 | 165 --sem->count; /* restore */ |
| 166 SDL_SetError("ReleaseSemaphore() failed"); | |
| 167 return -1; | |
| 168 } | |
| 169 return 0; | |
| 170 } |