view include/SDL_loadso.h @ 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
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* System dependent library loading routines                           */

/* Some things to keep in mind:                                        
   - These functions only work on C function names.  Other languages may
     have name mangling and intrinsic language support that varies from
     compiler to compiler.
   - Make sure you declare your function pointers with the same calling
     convention as the actual library function.  Your code will crash
     mysteriously if you do not do this.
   - Avoid namespace collisions.  If you load a symbol from the library,
     it is not defined whether or not it goes into the global symbol
     namespace for the application.  If it does and it conflicts with
     symbols in your code or other shared libraries, you will not get
     the results you expect. :)
*/


#ifndef _SDL_loadso_h
#define _SDL_loadso_h

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/* This function dynamically loads a shared object and returns a pointer
 * to the object handle (or NULL if there was an error).
 * The 'sofile' parameter is a system dependent name of the object file.
 */
extern DECLSPEC void * SDLCALL SDL_LoadObject(const char *sofile);

/* Given an object handle, this function looks up the address of the
 * named function in the shared object and returns it.  This address
 * is no longer valid after calling SDL_UnloadObject().
 */
extern DECLSPEC void * SDLCALL SDL_LoadFunction(void *handle, const char *name);

/* Unload a shared object from memory */
extern DECLSPEC void SDLCALL SDL_UnloadObject(void *handle);

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"

#endif /* _SDL_loadso_h */