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[gnulib.git] / m4 / fcntl_h.m4

diff --git a/m4/fcntl_h.m4 b/m4/fcntl_h.m4
index 35e4b51..fe7dffd 100644 (file)
--- a/m4/fcntl_h.m4
+++ b/m4/fcntl_h.m4
@@ -15,6 +15,9 @@ AC_DEFUN([gl_FCNTL_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
@@ -24,23 +27,52 @@ AC_DEFUN([gl_FCNTL_H],
              O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY
            };
          ]],
-         [[static char const sym[] = "conftest.sym";
-           if (O_NOFOLLOW)
-             {
-               if (symlink (".", sym) != 0)
-                 return 1;
-               if (0 <= open (sym, O_RDONLY | O_NOFOLLOW))
-                 return 1;
-             }
-           return !constants;]])],
+         [[
+           int status = !constants;
+           {
+             static char const sym[] = "conftest.sym";
+             if (symlink (".", sym) != 0
+                 || close (open (sym, O_RDONLY | O_NOFOLLOW)) == 0)
+               status |= 32;
+           }
+           {
+             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
+                 || st1.st_mtime <= st0.st_mtime
+                 || close (fd) != 0)
+               status |= 64;
+           }
+           return status;]])],
        [gl_cv_header_working_fcntl_h=yes],
-       [gl_cv_header_working_fcntl_h=no],
+       [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])])
 
-  if test $gl_cv_header_working_fcntl_h != yes; then
-    AC_DEFINE([O_NOFOLLOW_IS_INEFFECTIVE], 1,
-      [Define to 1 if O_NOFOLLOW is ineffective.])
-  fi
+  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.])
 
   gl_ABSOLUTE_HEADER([fcntl.h])
   ABSOLUTE_FCNTL_H=\"$gl_cv_absolute_fcntl_h\"