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# mprotect.m4 serial 1
dnl Copyright (C) 1993-2021 Free Software Foundation, Inc.
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License as published by the Free Software Foundation;
dnl either version 2 of the License, or (at your option) any later version.
dnl As a special exception to the GNU General Public License, this file
dnl may be distributed as part of a program that contains a configuration
dnl script generated by Autoconf, under the same distribution terms as
dnl the rest of that program.
dnl Test whether mprotect() works.
dnl Sets gl_cv_func_mprotect_works and defines HAVE_WORKING_MPROTECT.
AC_DEFUN([gl_FUNC_MPROTECT_WORKS],
[
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_REQUIRE([gl_FUNC_MMAP_ANON])
AC_CHECK_FUNCS([mprotect])
if test $ac_cv_func_mprotect = yes; then
AC_CACHE_CHECK([for working mprotect], [gl_cv_func_mprotect_works],
[if test $cross_compiling = no; then
mprotect_prog='
#include <sys/types.h>
/* Declare malloc(). */
#include <stdlib.h>
/* Declare getpagesize(). */
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef __hpux
extern
#ifdef __cplusplus
"C"
#endif
int getpagesize (void);
#endif
/* Declare mprotect(). */
#include <sys/mman.h>
char foo;
int main ()
{
unsigned long pagesize = getpagesize ();
#define page_align(address) (char*)((unsigned long)(address) & -pagesize)
'
no_mprotect=
AC_RUN_IFELSE(
[AC_LANG_SOURCE([
[$mprotect_prog
if ((pagesize - 1) & pagesize)
return 1;
return 0;
}
]])
],
[],
[no_mprotect=1],
[:])
mprotect_prog="$mprotect_prog"'
char* area = (char*) malloc (6 * pagesize);
char* fault_address = area + pagesize*7/2;
'
if test -z "$no_mprotect"; then
AC_RUN_IFELSE(
[AC_LANG_SOURCE([
GL_NOCRASH
[$mprotect_prog
nocrash_init();
if (mprotect (page_align (fault_address), pagesize, PROT_NONE) < 0)
return 0;
foo = *fault_address; /* this should cause an exception or signal */
return 0;
}
]])
],
[no_mprotect=1],
[],
[:])
fi
if test -z "$no_mprotect"; then
AC_RUN_IFELSE(
[AC_LANG_SOURCE([
GL_NOCRASH
[$mprotect_prog
nocrash_init();
if (mprotect (page_align (fault_address), pagesize, PROT_NONE) < 0)
return 0;
*fault_address = 'z'; /* this should cause an exception or signal */
return 0;
}
]])
],
[no_mprotect=1],
[],
[:])
fi
if test -z "$no_mprotect"; then
AC_RUN_IFELSE(
[AC_LANG_SOURCE([
GL_NOCRASH
[$mprotect_prog
nocrash_init();
if (mprotect (page_align (fault_address), pagesize, PROT_READ) < 0)
return 0;
*fault_address = 'z'; /* this should cause an exception or signal */
return 0;
}
]])
],
[no_mprotect=1],
[],
[:])
fi
if test -z "$no_mprotect"; then
AC_RUN_IFELSE(
[AC_LANG_SOURCE([
GL_NOCRASH
[$mprotect_prog
nocrash_init();
if (mprotect (page_align (fault_address), pagesize, PROT_READ) < 0)
return 1;
if (mprotect (page_align (fault_address), pagesize, PROT_READ | PROT_WRITE) < 0)
return 1;
*fault_address = 'z'; /* this should not cause an exception or signal */
return 0;
}
]])
],
[],
[no_mprotect=1],
[:])
fi
if test -z "$no_mprotect"; then
gl_cv_func_mprotect_works=yes
else
gl_cv_func_mprotect_works=no
fi
else
dnl When cross-compiling, assume the known behaviour.
case "$host_os" in
dnl Guess yes on Linux systems, glibc systems,
dnl macOS, BSD systems, AIX, HP-UX, IRIX, Solaris, Cygwin.
linux-* | linux | *-gnu* | gnu* | \
darwin* | freebsd* | dragonfly* | netbsd* | openbsd* | \
aix* | hpux* | irix* | solaris* | cygwin*)
gl_cv_func_mprotect_works="guessing yes" ;;
mingw*)
gl_cv_func_mprotect_works="guessing no" ;;
*)
dnl If we don't know, obey --enable-cross-guesses.
gl_cv_func_mprotect_works="$gl_cross_guess_normal" ;;
esac
fi
])
case "$gl_cv_func_mprotect_works" in
*yes)
AC_DEFINE([HAVE_WORKING_MPROTECT], [1],
[have a working mprotect() function])
;;
esac
fi
])
|
