From d10806928fc3d9f5b90011272ef8cd9a7ff53871 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Chigot?= <clement.chigot@atos.net>
Date: Tue, 14 Jan 2020 14:24:16 +0100
Subject: [PATCH] libbeat/common/file: fix fsync failure on AIX

On AIX, fsync syscall doesn't work with read-only files.
As os.Open is actually opening in read-only mode, it must be changed
for os.OpenFile with O_RDWR flag.
---
 libbeat/common/file/helper_aix.go   | 45 +++++++++++++++++++++++++++++
 libbeat/common/file/helper_other.go |  2 +-
 2 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 libbeat/common/file/helper_aix.go

diff --git a/libbeat/common/file/helper_aix.go b/libbeat/common/file/helper_aix.go
new file mode 100644
index 000000000..985b452c1
--- /dev/null
+++ b/libbeat/common/file/helper_aix.go
@@ -0,0 +1,45 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. licenses this file to you under
+// the Apache License, Version 2.0 (the "License"); you may
+// not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package file
+
+import (
+	"os"
+	"path/filepath"
+)
+
+// SafeFileRotate safely rotates an existing file under path and replaces it with the tempfile
+func SafeFileRotate(path, tempfile string) error {
+	parent := filepath.Dir(path)
+
+	if e := os.Rename(tempfile, path); e != nil {
+		return e
+	}
+
+	// best-effort fsync on parent directory. The fsync is required by some
+	// filesystems, so to update the parents directory metadata to actually
+	// contain the new file being rotated in.
+	// On AIX, fsync will fail if the file is opened in read-only mode,
+	// which is the case with os.Open.
+	f, err := os.OpenFile(parent, os.O_RDWR, 0)
+	if err != nil {
+		return nil // ignore error
+	}
+	defer f.Close()
+
+	return f.Sync()
+}
diff --git a/libbeat/common/file/helper_other.go b/libbeat/common/file/helper_other.go
index d166cb595..6347b7b28 100644
--- a/libbeat/common/file/helper_other.go
+++ b/libbeat/common/file/helper_other.go
@@ -15,7 +15,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-// +build !windows
+// +build !aix,!windows
 
 package file
 
-- 
2.22.0