Mercurial > sdl-ios-xcode
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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 | 65f4b2dd46b7 |
children | 31c2b8e4885e |
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# Configure paths for SDL # Sam Lantinga 9/21/99 # stolen from Manish Singh # stolen back from Frank Belew # stolen from Manish Singh # Shamelessly stolen from Owen Taylor dnl AM_PATH_SDL([MINIMUM-VERSION, [ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]]]) dnl Test for SDL, and define SDL_CFLAGS and SDL_LIBS dnl AC_DEFUN([AM_PATH_SDL], [dnl dnl Get the cflags and libraries from the sdl-config script dnl AC_ARG_WITH(sdl-prefix,[ --with-sdl-prefix=PFX Prefix where SDL is installed (optional)], sdl_prefix="$withval", sdl_prefix="") AC_ARG_WITH(sdl-exec-prefix,[ --with-sdl-exec-prefix=PFX Exec prefix where SDL is installed (optional)], sdl_exec_prefix="$withval", sdl_exec_prefix="") AC_ARG_ENABLE(sdltest, [ --disable-sdltest Do not try to compile and run a test SDL program], , enable_sdltest=yes) if test x$sdl_exec_prefix != x ; then sdl_args="$sdl_args --exec-prefix=$sdl_exec_prefix" if test x${SDL_CONFIG+set} != xset ; then SDL_CONFIG=$sdl_exec_prefix/bin/sdl-config fi fi if test x$sdl_prefix != x ; then sdl_args="$sdl_args --prefix=$sdl_prefix" if test x${SDL_CONFIG+set} != xset ; then SDL_CONFIG=$sdl_prefix/bin/sdl-config fi fi AC_REQUIRE([AC_CANONICAL_TARGET]) PATH="$prefix/bin:$prefix/usr/bin:$PATH" AC_PATH_PROG(SDL_CONFIG, sdl-config, no, [$PATH]) min_sdl_version=ifelse([$1], ,0.11.0,$1) AC_MSG_CHECKING(for SDL - version >= $min_sdl_version) no_sdl="" if test "$SDL_CONFIG" = "no" ; then no_sdl=yes else SDL_CFLAGS=`$SDL_CONFIG $sdlconf_args --cflags` SDL_LIBS=`$SDL_CONFIG $sdlconf_args --libs` sdl_major_version=`$SDL_CONFIG $sdl_args --version | \ sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\1/'` sdl_minor_version=`$SDL_CONFIG $sdl_args --version | \ sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\2/'` sdl_micro_version=`$SDL_CONFIG $sdl_config_args --version | \ sed 's/\([[0-9]]*\).\([[0-9]]*\).\([[0-9]]*\)/\3/'` if test "x$enable_sdltest" = "xyes" ; then ac_save_CFLAGS="$CFLAGS" ac_save_CXXFLAGS="$CXXFLAGS" ac_save_LIBS="$LIBS" CFLAGS="$CFLAGS $SDL_CFLAGS" CXXFLAGS="$CXXFLAGS $SDL_CFLAGS" LIBS="$LIBS $SDL_LIBS" dnl dnl Now check if the installed SDL is sufficiently new. (Also sanity dnl checks the results of sdl-config to some extent dnl rm -f conf.sdltest AC_TRY_RUN([ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "SDL.h" char* my_strdup (char *str) { char *new_str; if (str) { new_str = (char *)malloc ((strlen (str) + 1) * sizeof(char)); strcpy (new_str, str); } else new_str = NULL; return new_str; } int main (int argc, char *argv[]) { int major, minor, micro; char *tmp_version; /* This hangs on some systems (?) system ("touch conf.sdltest"); */ { FILE *fp = fopen("conf.sdltest", "a"); if ( fp ) fclose(fp); } /* HP/UX 9 (%@#!) writes to sscanf strings */ tmp_version = my_strdup("$min_sdl_version"); if (sscanf(tmp_version, "%d.%d.%d", &major, &minor, µ) != 3) { printf("%s, bad version string\n", "$min_sdl_version"); exit(1); } if (($sdl_major_version > major) || (($sdl_major_version == major) && ($sdl_minor_version > minor)) || (($sdl_major_version == major) && ($sdl_minor_version == minor) && ($sdl_micro_version >= micro))) { return 0; } else { printf("\n*** 'sdl-config --version' returned %d.%d.%d, but the minimum version\n", $sdl_major_version, $sdl_minor_version, $sdl_micro_version); printf("*** of SDL required is %d.%d.%d. If sdl-config is correct, then it is\n", major, minor, micro); printf("*** best to upgrade to the required version.\n"); printf("*** If sdl-config was wrong, set the environment variable SDL_CONFIG\n"); printf("*** to point to the correct copy of sdl-config, and remove the file\n"); printf("*** config.cache before re-running configure\n"); return 1; } } ],, no_sdl=yes,[echo $ac_n "cross compiling; assumed OK... $ac_c"]) CFLAGS="$ac_save_CFLAGS" LIBS="$ac_save_LIBS" fi fi if test "x$no_sdl" = x ; then AC_MSG_RESULT(yes) ifelse([$2], , :, [$2]) else AC_MSG_RESULT(no) if test "$SDL_CONFIG" = "no" ; then echo "*** The sdl-config script installed by SDL could not be found" echo "*** If SDL was installed in PREFIX, make sure PREFIX/bin is in" echo "*** your path, or set the SDL_CONFIG environment variable to the" echo "*** full path to sdl-config." else if test -f conf.sdltest ; then : else echo "*** Could not run SDL test program, checking why..." CFLAGS="$CFLAGS $SDL_CFLAGS" CXXFLAGS="$CXXFLAGS $SDL_CFLAGS" LIBS="$LIBS $SDL_LIBS" AC_TRY_LINK([ #include <stdio.h> #include "SDL.h" int main(int argc, char *argv[]) { return 0; } #undef main #define main K_and_R_C_main ], [ return 0; ], [ echo "*** The test program compiled, but did not run. This usually means" echo "*** that the run-time linker is not finding SDL or finding the wrong" echo "*** version of SDL. If it is not finding SDL, you'll need to set your" echo "*** LD_LIBRARY_PATH environment variable, or edit /etc/ld.so.conf to point" echo "*** to the installed location Also, make sure you have run ldconfig if that" echo "*** is required on your system" echo "***" echo "*** If you have an old version installed, it is best to remove it, although" echo "*** you may also be able to get things to work by modifying LD_LIBRARY_PATH"], [ echo "*** The test program failed to compile or link. See the file config.log for the" echo "*** exact error that occured. This usually means SDL was incorrectly installed" echo "*** or that you have moved SDL since it was installed. In the latter case, you" echo "*** may want to edit the sdl-config script: $SDL_CONFIG" ]) CFLAGS="$ac_save_CFLAGS" CXXFLAGS="$ac_save_CXXFLAGS" LIBS="$ac_save_LIBS" fi fi SDL_CFLAGS="" SDL_CXXFLAGS="" SDL_LIBS="" ifelse([$3], , :, [$3]) fi AC_SUBST(SDL_CFLAGS) AC_SUBST(SDL_LIBS) rm -f conf.sdltest ])