2
dnl Copyright (C) 2006, 2009-2011 Free Software Foundation, Inc.
3
dnl This file is free software; the Free Software Foundation
4
dnl gives unlimited permission to copy and/or distribute it,
5
dnl with or without modifications, as long as this notice is preserved.
7
dnl Written by Paul Eggert.
9
# Test whether the flags O_NOATIME and O_NOFOLLOW actually work.
10
# Define HAVE_WORKING_O_NOATIME to 1 if O_NOATIME works, or to 0 otherwise.
11
# Define HAVE_WORKING_O_NOFOLLOW to 1 if O_NOFOLLOW works, or to 0 otherwise.
12
AC_DEFUN([gl_FCNTL_O_FLAGS],
14
dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.
15
dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
17
m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
18
[AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
19
[AC_REQUIRE([AC_GNU_SOURCE])])
20
AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],
23
[[#include <sys/types.h>
33
static int const constants[] =
35
O_CREAT, O_EXCL, O_NOCTTY, O_TRUNC, O_APPEND,
36
O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY
40
int result = !constants;
42
static char const sym[] = "conftest.sym";
43
if (symlink (".", sym) != 0)
47
int fd = open (sym, O_RDONLY | O_NOFOLLOW);
57
static char const file[] = "confdefs.h";
58
int fd = open (file, O_RDONLY | O_NOATIME);
64
if (fstat (fd, &st0) != 0)
70
if (read (fd, &c, 1) != 1)
79
if (stat (file, &st1) != 0)
82
if (st0.st_atime != st1.st_atime)
90
[gl_cv_header_working_fcntl_h=yes],
92
4) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #(
93
64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #(
94
68) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #(
95
*) gl_cv_header_working_fcntl_h='no';;
97
[gl_cv_header_working_fcntl_h=cross-compiling])])
99
case $gl_cv_header_working_fcntl_h in #(
100
*O_NOATIME* | no | cross-compiling) ac_val=0;; #(
103
AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOATIME], [$ac_val],
104
[Define to 1 if O_NOATIME works.])
106
case $gl_cv_header_working_fcntl_h in #(
107
*O_NOFOLLOW* | no | cross-compiling) ac_val=0;; #(
110
AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOFOLLOW], [$ac_val],
111
[Define to 1 if O_NOFOLLOW works.])