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-rw-r--r--m4/fcntl-o.m4134
1 files changed, 134 insertions, 0 deletions
diff --git a/m4/fcntl-o.m4 b/m4/fcntl-o.m4
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+++ b/m4/fcntl-o.m4
@@ -0,0 +1,134 @@
+# fcntl-o.m4 serial 4
+dnl Copyright (C) 2006, 2009-2014 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.
+ dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
+ dnl AC_GNU_SOURCE.
+ m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
+ [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
+ [AC_REQUIRE([AC_GNU_SOURCE])])
+
+ AC_CHECK_HEADERS_ONCE([unistd.h])
+ AC_CHECK_FUNCS_ONCE([symlink])
+ 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>
+ #if HAVE_UNISTD_H
+ # include <unistd.h>
+ #else /* on Windows with MSVC */
+ # include <io.h>
+ # include <stdlib.h>
+ # defined sleep(n) _sleep ((n) * 1000)
+ #endif
+ #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 result = !constants;
+ #if HAVE_SYMLINK
+ {
+ static char const sym[] = "conftest.sym";
+ if (symlink ("/dev/null", sym) != 0)
+ result |= 2;
+ else
+ {
+ int fd = open (sym, O_WRONLY | O_NOFOLLOW | O_CREAT, 0);
+ if (fd >= 0)
+ {
+ close (fd);
+ result |= 4;
+ }
+ }
+ if (unlink (sym) != 0 || symlink (".", sym) != 0)
+ result |= 2;
+ else
+ {
+ int fd = open (sym, O_RDONLY | O_NOFOLLOW);
+ if (fd >= 0)
+ {
+ close (fd);
+ result |= 4;
+ }
+ }
+ unlink (sym);
+ }
+ #endif
+ {
+ static char const file[] = "confdefs.h";
+ int fd = open (file, O_RDONLY | O_NOATIME);
+ if (fd < 0)
+ result |= 8;
+ else
+ {
+ struct stat st0;
+ if (fstat (fd, &st0) != 0)
+ result |= 16;
+ else
+ {
+ char c;
+ sleep (1);
+ if (read (fd, &c, 1) != 1)
+ result |= 24;
+ else
+ {
+ if (close (fd) != 0)
+ result |= 32;
+ else
+ {
+ struct stat st1;
+ if (stat (file, &st1) != 0)
+ result |= 40;
+ else
+ if (st0.st_atime != st1.st_atime)
+ result |= 64;
+ }
+ }
+ }
+ }
+ }
+ return result;]])],
+ [gl_cv_header_working_fcntl_h=yes],
+ [case $? in #(
+ 4) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #(
+ 64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #(
+ 68) 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.])
+])