diff options
Diffstat (limited to 'gl/m4/fcntl-o.m4')
| -rw-r--r-- | gl/m4/fcntl-o.m4 | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/gl/m4/fcntl-o.m4 b/gl/m4/fcntl-o.m4 new file mode 100644 index 00000000..d416a61c --- /dev/null +++ b/gl/m4/fcntl-o.m4 @@ -0,0 +1,81 @@ +# fcntl-o.m4 serial 1 +dnl Copyright (C) 2006, 2009-2010 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. + +# 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_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> + #include <unistd.h> + #include <fcntl.h> + #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 status = !constants; + { + static char const sym[] = "conftest.sym"; + if (symlink (".", sym) != 0 + || close (open (sym, O_RDONLY | O_NOFOLLOW)) == 0) + status |= 32; + unlink (sym); + } + { + static char const file[] = "confdefs.h"; + int fd = open (file, O_RDONLY | O_NOATIME); + char c; + struct stat st0, st1; + if (fd < 0 + || fstat (fd, &st0) != 0 + || sleep (1) != 0 + || read (fd, &c, 1) != 1 + || close (fd) != 0 + || stat (file, &st1) != 0 + || st0.st_atime != st1.st_atime) + status |= 64; + } + return status;]])], + [gl_cv_header_working_fcntl_h=yes], + [case $? in #( + 32) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #( + 64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #( + 96) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #( + *) gl_cv_header_working_fcntl_h='no';; + esac], + [gl_cv_header_working_fcntl_h=cross-compiling])]) + + 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.]) +]) |