mirror of
https://git.zap.org.au/git/trader.git
synced 2024-09-01 17:14:15 -04:00
These files have been created by running ./build-aux/bootstrap with Gnulib as at commit f9b39c4e337f1dc0dd07c4f3985c476fb875d799 (with a date stamp of Sun Jul 31 23:28:18 2022 +0200), Autoconf 2.71, Automake 1.16.5, Gettext 0.21 and pkgconf 1.8.0.
107 lines
3.3 KiB
Plaintext
107 lines
3.3 KiB
Plaintext
# memchr.m4 serial 18
|
|
dnl Copyright (C) 2002-2004, 2009-2022 Free Software Foundation, Inc.
|
|
dnl This file is free software; the Free Software Foundation
|
|
dnl gives unlimited permission to copy and/or distribute it,
|
|
dnl with or without modifications, as long as this notice is preserved.
|
|
|
|
AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
|
|
[
|
|
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
|
|
|
|
dnl Check for prerequisites for memory fence checks.
|
|
gl_FUNC_MMAP_ANON
|
|
AC_CHECK_HEADERS_ONCE([sys/mman.h])
|
|
AC_CHECK_FUNCS_ONCE([mprotect])
|
|
|
|
AC_REQUIRE([gl_STRING_H_DEFAULTS])
|
|
# Detect platform-specific bugs in some versions of glibc:
|
|
# memchr should not dereference anything with length 0
|
|
# https://bugzilla.redhat.com/show_bug.cgi?id=499689
|
|
# memchr should not dereference overestimated length after a match
|
|
# https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737
|
|
# https://sourceware.org/bugzilla/show_bug.cgi?id=10162
|
|
# memchr should cast the second argument to 'unsigned char'.
|
|
# This bug exists in Android 4.3.
|
|
# Assume that memchr works on platforms that lack mprotect.
|
|
AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works],
|
|
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
|
|
#include <string.h>
|
|
#if HAVE_SYS_MMAN_H
|
|
# include <fcntl.h>
|
|
# include <unistd.h>
|
|
# include <sys/types.h>
|
|
# include <sys/mman.h>
|
|
# ifndef MAP_FILE
|
|
# define MAP_FILE 0
|
|
# endif
|
|
#endif
|
|
]], [[
|
|
int result = 0;
|
|
char *fence = NULL;
|
|
#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)
|
|
fence = two_pages + pagesize;
|
|
}
|
|
#endif
|
|
if (fence)
|
|
{
|
|
/* Test against bugs on glibc systems. */
|
|
if (memchr (fence, 0, 0))
|
|
result |= 1;
|
|
strcpy (fence - 9, "12345678");
|
|
if (memchr (fence - 9, 0, 79) != fence - 1)
|
|
result |= 2;
|
|
if (memchr (fence - 1, 0, 3) != fence - 1)
|
|
result |= 4;
|
|
/* Test against bug on AIX 7.2. */
|
|
if (memchr (fence - 4, '6', 16) != fence - 4)
|
|
result |= 8;
|
|
}
|
|
/* Test against bug on Android 4.3. */
|
|
{
|
|
char input[3];
|
|
input[0] = 'a';
|
|
input[1] = 'b';
|
|
input[2] = 'c';
|
|
if (memchr (input, 0x789abc00 | 'b', 3) != input + 1)
|
|
result |= 16;
|
|
}
|
|
return result;
|
|
]])],
|
|
[gl_cv_func_memchr_works=yes],
|
|
[gl_cv_func_memchr_works=no],
|
|
[case "$host_os" in
|
|
# Guess no on Android.
|
|
linux*-android*) gl_cv_func_memchr_works="guessing no" ;;
|
|
# Guess yes on native Windows.
|
|
mingw*) gl_cv_func_memchr_works="guessing yes" ;;
|
|
# If we don't know, obey --enable-cross-guesses.
|
|
*) gl_cv_func_memchr_works="$gl_cross_guess_normal" ;;
|
|
esac
|
|
])
|
|
])
|
|
case "$gl_cv_func_memchr_works" in
|
|
*yes) ;;
|
|
*) REPLACE_MEMCHR=1 ;;
|
|
esac
|
|
])
|
|
|
|
# Prerequisites of lib/memchr.c.
|
|
AC_DEFUN([gl_PREREQ_MEMCHR], [
|
|
AC_CHECK_HEADERS([bp-sym.h])
|
|
])
|