From 36082a2fe36ecd800d784ae44c14f1f18c66a7e9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 09:33:12 +0200 Subject: Adding upstream version 3.7.9. Signed-off-by: Daniel Baumann --- src/gl/tests/zerosize-ptr.h | 82 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 src/gl/tests/zerosize-ptr.h (limited to 'src/gl/tests/zerosize-ptr.h') diff --git a/src/gl/tests/zerosize-ptr.h b/src/gl/tests/zerosize-ptr.h new file mode 100644 index 0000000..bfeff50 --- /dev/null +++ b/src/gl/tests/zerosize-ptr.h @@ -0,0 +1,82 @@ +/* Return a pointer to a zero-size object in memory. + Copyright (C) 2009-2021 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +/* ISO C 99 does not allow memcmp(), memchr() etc. to be invoked with a NULL + argument. Therefore this file produces a non-NULL pointer which cannot + be dereferenced, if possible. */ + +/* On Android, when targeting Android 4.4 or older with a GCC toolchain, + prevent a compilation error + "error: call to 'mmap' declared with attribute error: mmap is not + available with _FILE_OFFSET_BITS=64 when using GCC until android-21. + Either raise your minSdkVersion, disable _FILE_OFFSET_BITS=64, or + switch to Clang." + The files that we access in this compilation unit are less than 2 GB + large. */ +#if defined __ANDROID__ +# undef _FILE_OFFSET_BITS +# undef __USE_FILE_OFFSET64 +#endif + +#include + +/* Test whether mmap() and mprotect() are available. + We don't use HAVE_MMAP, because AC_FUNC_MMAP would not define it on HP-UX. + HAVE_MPROTECT is not enough, because mingw does not have mmap() but has an + mprotect() function in libgcc.a. + And OS/2 kLIBC has and mprotect(), but not mmap(). */ +#if HAVE_SYS_MMAN_H && HAVE_MPROTECT && !defined __KLIBC__ +# include +# include +# include +# include +/* Define MAP_FILE when it isn't otherwise. */ +# ifndef MAP_FILE +# define MAP_FILE 0 +# endif +#endif + +/* Return a pointer to a zero-size object in memory (that is, actually, a + pointer to a page boundary where the previous page is readable and writable + and the next page is neither readable not writable), if possible. + Return NULL otherwise. */ + +static void * +zerosize_ptr (void) +{ +/* Use mmap and mprotect when they exist. Don't test HAVE_MMAP, because it is + not defined on HP-UX 11 (since it does not support MAP_FIXED). */ +#if HAVE_SYS_MMAN_H && HAVE_MPROTECT && !defined __KLIBC__ +# if HAVE_MAP_ANONYMOUS + const int flags = MAP_ANONYMOUS | MAP_PRIVATE; + const int fd = -1; +# else /* !HAVE_MAP_ANONYMOUS */ + const int flags = MAP_FILE | MAP_PRIVATE; + int fd = open ("/dev/zero", O_RDONLY, 0666); + if (fd >= 0) +# endif + { + int pagesize = getpagesize (); + char *two_pages = + (char *) mmap (NULL, 2 * pagesize, PROT_READ | PROT_WRITE, + flags, fd, 0); + if (two_pages != (char *)(-1) + && mprotect (two_pages + pagesize, pagesize, PROT_NONE) == 0) + return two_pages + pagesize; + } +#endif + return NULL; +} -- cgit v1.2.3