From 344f8a1814b8df2b4222b3aa96a0a0a2743ba496 Mon Sep 17 00:00:00 2001
From: Daniel Black <daniel@linux.ibm.com>
Date: Tue, 15 Jan 2019 16:10:11 +1100
Subject: [PATCH] Linux use O_TMPFILE for create_temp_file

O_TMPFILE creates a tempfile not attached to a filename.

We preserve a state O_TMPFILE_works because kernel version or
filesystem could cause failure, most likely permanently.
---
 include/my_sys.h     |  1 +
 mysys/mf_tempfile.cc | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/my_sys.h b/include/my_sys.h
index 63a0aede28d..8f3660a721b 100644
--- a/include/my_sys.h
+++ b/include/my_sys.h
@@ -304,6 +304,7 @@ enum file_type {
   STREAM_BY_FOPEN,
   STREAM_BY_FDOPEN,
   FILE_BY_MKSTEMP,
+  FILE_BY_O_TMPFILE,
   FILE_BY_DUP
 };
 
diff --git a/mysys/mf_tempfile.cc b/mysys/mf_tempfile.cc
index f2bf1b18036..12790ffefcd 100644
--- a/mysys/mf_tempfile.cc
+++ b/mysys/mf_tempfile.cc
@@ -118,6 +118,32 @@ File create_temp_file(char *to, const char *dir, const char *prefix,
   }
 
 #else /* mkstemp() is available on all non-Windows supported platforms. */
+#ifdef O_TMPFILE
+  {
+    static int O_TMPFILE_works = 1;
+
+    if (O_TMPFILE_works)
+    {
+      /* explictly don't use O_EXCL here has it has a different
+         meaning with O_TMPFILE
+      */
+      if ((file = open(dir, O_RDWR | O_TMPFILE | O_CLOEXEC,
+                      S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP)) >= 0)
+      {
+        snprintf(to, FN_REFLEN, "%s/#sql/fd=%d", dir, file);
+        file = my_register_filename(file, to, FILE_BY_O_TMPFILE,
+                                    EE_CANTCREATEFILE, MyFlags);
+      }
+      else if (errno == EOPNOTSUPP || errno == EINVAL)
+      {
+        my_printf_error(EE_CANTCREATEFILE, "O_TMPFILE is not supported on %s "
+                        "(disabling future attempts)", MYF(0), dir);
+        O_TMPFILE_works= 0;
+      }
+    }
+  }
+  if (file == -1)
+#endif /* O_TMPFILE */
   {
     char prefix_buff[30];
     uint pfx_len;