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1 | # fcntl-o.m4 serial 1 |
2 | dnl Copyright (C) 2006, 2009, 2010 Free Software Foundation, Inc. | |
8912421c LC |
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 | ||
8912421c LC |
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], | |
13 | [ | |
14 | dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW. | |
15 | AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) | |
16 | AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h], | |
17 | [AC_RUN_IFELSE( | |
18 | [AC_LANG_PROGRAM( | |
1cd4fffc LC |
19 | [[#include <sys/types.h> |
20 | #include <sys/stat.h> | |
21 | #include <unistd.h> | |
22 | #include <fcntl.h> | |
23 | #ifndef O_NOATIME | |
24 | #define O_NOATIME 0 | |
25 | #endif | |
26 | #ifndef O_NOFOLLOW | |
27 | #define O_NOFOLLOW 0 | |
28 | #endif | |
29 | static int const constants[] = | |
30 | { | |
31 | O_CREAT, O_EXCL, O_NOCTTY, O_TRUNC, O_APPEND, | |
32 | O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY | |
33 | }; | |
34 | ]], | |
35 | [[ | |
36 | int status = !constants; | |
37 | { | |
38 | static char const sym[] = "conftest.sym"; | |
39 | if (symlink (".", sym) != 0 | |
40 | || close (open (sym, O_RDONLY | O_NOFOLLOW)) == 0) | |
41 | status |= 32; | |
42 | unlink (sym); | |
43 | } | |
44 | { | |
45 | static char const file[] = "confdefs.h"; | |
46 | int fd = open (file, O_RDONLY | O_NOATIME); | |
47 | char c; | |
48 | struct stat st0, st1; | |
49 | if (fd < 0 | |
50 | || fstat (fd, &st0) != 0 | |
51 | || sleep (1) != 0 | |
52 | || read (fd, &c, 1) != 1 | |
53 | || close (fd) != 0 | |
54 | || stat (file, &st1) != 0 | |
55 | || st0.st_atime != st1.st_atime) | |
56 | status |= 64; | |
57 | } | |
58 | return status;]])], | |
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59 | [gl_cv_header_working_fcntl_h=yes], |
60 | [case $? in #( | |
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61 | 32) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #( |
62 | 64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #( | |
63 | 96) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #( | |
64 | *) gl_cv_header_working_fcntl_h='no';; | |
65 | esac], | |
8912421c LC |
66 | [gl_cv_header_working_fcntl_h=cross-compiling])]) |
67 | ||
68 | case $gl_cv_header_working_fcntl_h in #( | |
69 | *O_NOATIME* | no | cross-compiling) ac_val=0;; #( | |
70 | *) ac_val=1;; | |
71 | esac | |
72 | AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOATIME], [$ac_val], | |
73 | [Define to 1 if O_NOATIME works.]) | |
74 | ||
75 | case $gl_cv_header_working_fcntl_h in #( | |
76 | *O_NOFOLLOW* | no | cross-compiling) ac_val=0;; #( | |
77 | *) ac_val=1;; | |
78 | esac | |
79 | AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOFOLLOW], [$ac_val], | |
80 | [Define to 1 if O_NOFOLLOW works.]) | |
81 | ]) |