# fcntl-o.m4 serial 2

dnl Copyright (C) 2006, 2009-2010 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.

dnl Written by Paul Eggert.

# Test whether the flags O_NOATIME and O_NOFOLLOW actually work.

# Define HAVE_WORKING_O_NOATIME to 1 if O_NOATIME works, or to 0 otherwise.

# Define HAVE_WORKING_O_NOFOLLOW to 1 if O_NOFOLLOW works, or to 0 otherwise.

AC_DEFUN([gl_FCNTL_O_FLAGS],

[

dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.

dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes

dnl AC_GNU_SOURCE.

m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],

[AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],

[AC_REQUIRE([AC_GNU_SOURCE])])

AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],

[AC_RUN_IFELSE(

[AC_LANG_PROGRAM(

[[#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include <fcntl.h>

#ifndef O_NOATIME

#define O_NOATIME 0

#endif

#ifndef O_NOFOLLOW

#define O_NOFOLLOW 0

#endif

static int const constants[] =

{

O_CREAT, O_EXCL, O_NOCTTY, O_TRUNC, O_APPEND,

O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY

};

]],

[[

int status = !constants;

{

static char const sym[] = "conftest.sym";

if (symlink (".", sym) != 0

|| close (open (sym, O_RDONLY | O_NOFOLLOW)) == 0)

status |= 32;

unlink (sym);

}

{

static char const file[] = "confdefs.h";

int fd = open (file, O_RDONLY | O_NOATIME);

char c;

struct stat st0, st1;

if (fd < 0

|| fstat (fd, &st0) != 0

|| sleep (1) != 0

|| read (fd, &c, 1) != 1

|| close (fd) != 0

|| stat (file, &st1) != 0

|| st0.st_atime != st1.st_atime)

status |= 64;

}

return status;]])],

[gl_cv_header_working_fcntl_h=yes],

[case $? in #(

32) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #(

64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #(

96) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #(

*) gl_cv_header_working_fcntl_h='no';;

esac],

[gl_cv_header_working_fcntl_h=cross-compiling])])

case $gl_cv_header_working_fcntl_h in #(

*O_NOATIME* | no | cross-compiling) ac_val=0;; #(

*) ac_val=1;;

esac

AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOATIME], [$ac_val],

[Define to 1 if O_NOATIME works.])

case $gl_cv_header_working_fcntl_h in #(

*O_NOFOLLOW* | no | cross-compiling) ac_val=0;; #(

*) ac_val=1;;

esac

AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOFOLLOW], [$ac_val],

[Define to 1 if O_NOFOLLOW works.])

])