140 lines
4.7 KiB
Text
140 lines
4.7 KiB
Text
# fcntl-o.m4 serial 7
|
|
dnl Copyright (C) 2006, 2009-2023 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.
|
|
|
|
AC_PREREQ([2.60])
|
|
|
|
# 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.
|
|
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
|
|
|
|
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
|
|
AC_CHECK_HEADERS_ONCE([unistd.h])
|
|
AC_CHECK_FUNCS_ONCE([symlink])
|
|
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>
|
|
#if HAVE_UNISTD_H
|
|
# include <unistd.h>
|
|
#else /* on Windows with MSVC */
|
|
# include <io.h>
|
|
# include <stdlib.h>
|
|
# defined sleep(n) _sleep ((n) * 1000)
|
|
#endif
|
|
#include <fcntl.h>
|
|
]GL_MDA_DEFINES[
|
|
#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 result = !constants;
|
|
#if HAVE_SYMLINK
|
|
{
|
|
static char const sym[] = "conftest.sym";
|
|
if (symlink ("/dev/null", sym) != 0)
|
|
result |= 2;
|
|
else
|
|
{
|
|
int fd = open (sym, O_WRONLY | O_NOFOLLOW | O_CREAT, 0);
|
|
if (fd >= 0)
|
|
{
|
|
close (fd);
|
|
result |= 4;
|
|
}
|
|
}
|
|
if (unlink (sym) != 0 || symlink (".", sym) != 0)
|
|
result |= 2;
|
|
else
|
|
{
|
|
int fd = open (sym, O_RDONLY | O_NOFOLLOW);
|
|
if (fd >= 0)
|
|
{
|
|
close (fd);
|
|
result |= 4;
|
|
}
|
|
}
|
|
unlink (sym);
|
|
}
|
|
#endif
|
|
{
|
|
static char const file[] = "confdefs.h";
|
|
int fd = open (file, O_RDONLY | O_NOATIME);
|
|
if (fd < 0)
|
|
result |= 8;
|
|
else
|
|
{
|
|
struct stat st0;
|
|
if (fstat (fd, &st0) != 0)
|
|
result |= 16;
|
|
else
|
|
{
|
|
char c;
|
|
sleep (1);
|
|
if (read (fd, &c, 1) != 1)
|
|
result |= 24;
|
|
else
|
|
{
|
|
if (close (fd) != 0)
|
|
result |= 32;
|
|
else
|
|
{
|
|
struct stat st1;
|
|
if (stat (file, &st1) != 0)
|
|
result |= 40;
|
|
else
|
|
if (st0.st_atime != st1.st_atime)
|
|
result |= 64;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return result;]])],
|
|
[gl_cv_header_working_fcntl_h=yes],
|
|
[case $? in #(
|
|
4) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #(
|
|
64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #(
|
|
68) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #(
|
|
*) gl_cv_header_working_fcntl_h='no';;
|
|
esac],
|
|
[case "$host_os" in
|
|
# Guess 'no' on native Windows.
|
|
mingw*) gl_cv_header_working_fcntl_h='no' ;;
|
|
*) gl_cv_header_working_fcntl_h=cross-compiling ;;
|
|
esac
|
|
])
|
|
])
|
|
|
|
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.])
|
|
])
|