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c0c3707f | 1 | # fcntl-o.m4 serial 6 |
5df4cba6 | 2 | dnl Copyright (C) 2006, 2009-2020 Free Software Foundation, Inc. |
8690e634 JK |
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. | |
6 | ||
7 | dnl Written by Paul Eggert. | |
8 | ||
c0c3707f CB |
9 | AC_PREREQ([2.60]) |
10 | ||
8690e634 JK |
11 | # Test whether the flags O_NOATIME and O_NOFOLLOW actually work. |
12 | # Define HAVE_WORKING_O_NOATIME to 1 if O_NOATIME works, or to 0 otherwise. | |
13 | # Define HAVE_WORKING_O_NOFOLLOW to 1 if O_NOFOLLOW works, or to 0 otherwise. | |
14 | AC_DEFUN([gl_FCNTL_O_FLAGS], | |
15 | [ | |
16 | dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW. | |
c0c3707f | 17 | AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) |
8690e634 | 18 | |
c0c3707f | 19 | AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles |
8690e634 JK |
20 | AC_CHECK_HEADERS_ONCE([unistd.h]) |
21 | AC_CHECK_FUNCS_ONCE([symlink]) | |
22 | AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h], | |
23 | [AC_RUN_IFELSE( | |
24 | [AC_LANG_PROGRAM( | |
25 | [[#include <sys/types.h> | |
26 | #include <sys/stat.h> | |
27 | #if HAVE_UNISTD_H | |
28 | # include <unistd.h> | |
29 | #else /* on Windows with MSVC */ | |
30 | # include <io.h> | |
31 | # include <stdlib.h> | |
32 | # defined sleep(n) _sleep ((n) * 1000) | |
33 | #endif | |
34 | #include <fcntl.h> | |
35 | #ifndef O_NOATIME | |
36 | #define O_NOATIME 0 | |
37 | #endif | |
38 | #ifndef O_NOFOLLOW | |
39 | #define O_NOFOLLOW 0 | |
40 | #endif | |
41 | static int const constants[] = | |
42 | { | |
43 | O_CREAT, O_EXCL, O_NOCTTY, O_TRUNC, O_APPEND, | |
44 | O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY | |
45 | }; | |
46 | ]], | |
47 | [[ | |
48 | int result = !constants; | |
49 | #if HAVE_SYMLINK | |
50 | { | |
51 | static char const sym[] = "conftest.sym"; | |
a512b375 JB |
52 | if (symlink ("/dev/null", sym) != 0) |
53 | result |= 2; | |
54 | else | |
55 | { | |
56 | int fd = open (sym, O_WRONLY | O_NOFOLLOW | O_CREAT, 0); | |
57 | if (fd >= 0) | |
58 | { | |
59 | close (fd); | |
60 | result |= 4; | |
61 | } | |
62 | } | |
63 | if (unlink (sym) != 0 || symlink (".", sym) != 0) | |
8690e634 JK |
64 | result |= 2; |
65 | else | |
66 | { | |
67 | int fd = open (sym, O_RDONLY | O_NOFOLLOW); | |
68 | if (fd >= 0) | |
69 | { | |
70 | close (fd); | |
71 | result |= 4; | |
72 | } | |
73 | } | |
74 | unlink (sym); | |
75 | } | |
76 | #endif | |
77 | { | |
78 | static char const file[] = "confdefs.h"; | |
79 | int fd = open (file, O_RDONLY | O_NOATIME); | |
80 | if (fd < 0) | |
81 | result |= 8; | |
82 | else | |
83 | { | |
84 | struct stat st0; | |
85 | if (fstat (fd, &st0) != 0) | |
86 | result |= 16; | |
87 | else | |
88 | { | |
89 | char c; | |
90 | sleep (1); | |
91 | if (read (fd, &c, 1) != 1) | |
92 | result |= 24; | |
93 | else | |
94 | { | |
95 | if (close (fd) != 0) | |
96 | result |= 32; | |
97 | else | |
98 | { | |
99 | struct stat st1; | |
100 | if (stat (file, &st1) != 0) | |
101 | result |= 40; | |
102 | else | |
103 | if (st0.st_atime != st1.st_atime) | |
104 | result |= 64; | |
105 | } | |
106 | } | |
107 | } | |
108 | } | |
109 | } | |
110 | return result;]])], | |
111 | [gl_cv_header_working_fcntl_h=yes], | |
112 | [case $? in #( | |
113 | 4) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #( | |
114 | 64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #( | |
115 | 68) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #( | |
116 | *) gl_cv_header_working_fcntl_h='no';; | |
117 | esac], | |
c0c3707f CB |
118 | [case "$host_os" in |
119 | # Guess 'no' on native Windows. | |
120 | mingw*) gl_cv_header_working_fcntl_h='no' ;; | |
121 | *) gl_cv_header_working_fcntl_h=cross-compiling ;; | |
122 | esac | |
123 | ]) | |
124 | ]) | |
8690e634 JK |
125 | |
126 | case $gl_cv_header_working_fcntl_h in #( | |
127 | *O_NOATIME* | no | cross-compiling) ac_val=0;; #( | |
128 | *) ac_val=1;; | |
129 | esac | |
130 | AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOATIME], [$ac_val], | |
131 | [Define to 1 if O_NOATIME works.]) | |
132 | ||
133 | case $gl_cv_header_working_fcntl_h in #( | |
134 | *O_NOFOLLOW* | no | cross-compiling) ac_val=0;; #( | |
135 | *) ac_val=1;; | |
136 | esac | |
137 | AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOFOLLOW], [$ac_val], | |
138 | [Define to 1 if O_NOFOLLOW works.]) | |
139 | ]) |