1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
# fcntl-o.m4 serial 7
dnl Copyright (C) 2006, 2009-2020 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.])
])
|
