| 1 | # fcntl-o.m4 serial 4 |
| 2 | dnl Copyright (C) 2006, 2009-2014 Free Software Foundation, Inc. |
| 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 | |
| 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 | dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes |
| 16 | dnl AC_GNU_SOURCE. |
| 17 | m4_ifdef([AC_USE_SYSTEM_EXTENSIONS], |
| 18 | [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])], |
| 19 | [AC_REQUIRE([AC_GNU_SOURCE])]) |
| 20 | |
| 21 | AC_CHECK_HEADERS_ONCE([unistd.h]) |
| 22 | AC_CHECK_FUNCS_ONCE([symlink]) |
| 23 | AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h], |
| 24 | [AC_RUN_IFELSE( |
| 25 | [AC_LANG_PROGRAM( |
| 26 | [[#include <sys/types.h> |
| 27 | #include <sys/stat.h> |
| 28 | #if HAVE_UNISTD_H |
| 29 | # include <unistd.h> |
| 30 | #else /* on Windows with MSVC */ |
| 31 | # include <io.h> |
| 32 | # include <stdlib.h> |
| 33 | # defined sleep(n) _sleep ((n) * 1000) |
| 34 | #endif |
| 35 | #include <fcntl.h> |
| 36 | #ifndef O_NOATIME |
| 37 | #define O_NOATIME 0 |
| 38 | #endif |
| 39 | #ifndef O_NOFOLLOW |
| 40 | #define O_NOFOLLOW 0 |
| 41 | #endif |
| 42 | static int const constants[] = |
| 43 | { |
| 44 | O_CREAT, O_EXCL, O_NOCTTY, O_TRUNC, O_APPEND, |
| 45 | O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY |
| 46 | }; |
| 47 | ]], |
| 48 | [[ |
| 49 | int result = !constants; |
| 50 | #if HAVE_SYMLINK |
| 51 | { |
| 52 | static char const sym[] = "conftest.sym"; |
| 53 | if (symlink ("/dev/null", sym) != 0) |
| 54 | result |= 2; |
| 55 | else |
| 56 | { |
| 57 | int fd = open (sym, O_WRONLY | O_NOFOLLOW | O_CREAT, 0); |
| 58 | if (fd >= 0) |
| 59 | { |
| 60 | close (fd); |
| 61 | result |= 4; |
| 62 | } |
| 63 | } |
| 64 | if (unlink (sym) != 0 || symlink (".", sym) != 0) |
| 65 | result |= 2; |
| 66 | else |
| 67 | { |
| 68 | int fd = open (sym, O_RDONLY | O_NOFOLLOW); |
| 69 | if (fd >= 0) |
| 70 | { |
| 71 | close (fd); |
| 72 | result |= 4; |
| 73 | } |
| 74 | } |
| 75 | unlink (sym); |
| 76 | } |
| 77 | #endif |
| 78 | { |
| 79 | static char const file[] = "confdefs.h"; |
| 80 | int fd = open (file, O_RDONLY | O_NOATIME); |
| 81 | if (fd < 0) |
| 82 | result |= 8; |
| 83 | else |
| 84 | { |
| 85 | struct stat st0; |
| 86 | if (fstat (fd, &st0) != 0) |
| 87 | result |= 16; |
| 88 | else |
| 89 | { |
| 90 | char c; |
| 91 | sleep (1); |
| 92 | if (read (fd, &c, 1) != 1) |
| 93 | result |= 24; |
| 94 | else |
| 95 | { |
| 96 | if (close (fd) != 0) |
| 97 | result |= 32; |
| 98 | else |
| 99 | { |
| 100 | struct stat st1; |
| 101 | if (stat (file, &st1) != 0) |
| 102 | result |= 40; |
| 103 | else |
| 104 | if (st0.st_atime != st1.st_atime) |
| 105 | result |= 64; |
| 106 | } |
| 107 | } |
| 108 | } |
| 109 | } |
| 110 | } |
| 111 | return result;]])], |
| 112 | [gl_cv_header_working_fcntl_h=yes], |
| 113 | [case $? in #( |
| 114 | 4) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #( |
| 115 | 64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #( |
| 116 | 68) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #( |
| 117 | *) gl_cv_header_working_fcntl_h='no';; |
| 118 | esac], |
| 119 | [gl_cv_header_working_fcntl_h=cross-compiling])]) |
| 120 | |
| 121 | case $gl_cv_header_working_fcntl_h in #( |
| 122 | *O_NOATIME* | no | cross-compiling) ac_val=0;; #( |
| 123 | *) ac_val=1;; |
| 124 | esac |
| 125 | AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOATIME], [$ac_val], |
| 126 | [Define to 1 if O_NOATIME works.]) |
| 127 | |
| 128 | case $gl_cv_header_working_fcntl_h in #( |
| 129 | *O_NOFOLLOW* | no | cross-compiling) ac_val=0;; #( |
| 130 | *) ac_val=1;; |
| 131 | esac |
| 132 | AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOFOLLOW], [$ac_val], |
| 133 | [Define to 1 if O_NOFOLLOW works.]) |
| 134 | ]) |