1# fcntl-o.m4 serial 1 2dnl Copyright (C) 2006, 2009-2010 Free Software Foundation, Inc. 3dnl This file is free software; the Free Software Foundation 4dnl gives unlimited permission to copy and/or distribute it, 5dnl with or without modifications, as long as this notice is preserved. 6 7dnl 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. 12AC_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( 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;]])], 59 [gl_cv_header_working_fcntl_h=yes], 60 [case $? in #( 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], 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]) 82