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Diffstat (limited to 'gl/tests/zerosize-ptr.h')
-rw-r--r-- | gl/tests/zerosize-ptr.h | 68 |
1 files changed, 0 insertions, 68 deletions
diff --git a/gl/tests/zerosize-ptr.h b/gl/tests/zerosize-ptr.h deleted file mode 100644 index e6ff672b64..0000000000 --- a/gl/tests/zerosize-ptr.h +++ /dev/null @@ -1,68 +0,0 @@ -/* Return a pointer to a zero-size object in memory. - Copyright (C) 2009-2016 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 <http://www.gnu.org/licenses/>. */ - -/* 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. */ - -#include <stdlib.h> - -/* 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. */ -#if HAVE_SYS_MMAN_H && HAVE_MPROTECT -# include <fcntl.h> -# include <unistd.h> -# include <sys/types.h> -# include <sys/mman.h> -/* 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 -# 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; -} |