From 4429570388d0f767c93a5a3ccc76e70668e9fecc Mon Sep 17 00:00:00 2001
From: Ben McClelland <ben.mcclelland@versity.com>
Date: Thu, 18 Apr 2024 18:17:17 -0700
Subject: [PATCH] fix: use xattr.ENOATTR check for posix xattrs

The xattr package has a more universal error type for xattrs
not existing. Use this for better platform compatibility.

This also adds the xattr.XATTR_SUPPORTED check for platform
xattr suport in xattr package.

Fixes #527
---
 backend/meta/xattr.go                 | 19 +++++++++++++++----
 backend/meta/xattr_with_enodata.go    | 24 ------------------------
 backend/meta/xattr_without_enodata.go | 24 ------------------------
 cmd/versitygw/posix.go                |  6 +++---
 4 files changed, 18 insertions(+), 55 deletions(-)
 delete mode 100644 backend/meta/xattr_with_enodata.go
 delete mode 100644 backend/meta/xattr_without_enodata.go

diff --git a/backend/meta/xattr.go b/backend/meta/xattr.go
index c7c16d2..c3ea577 100644
--- a/backend/meta/xattr.go
+++ b/backend/meta/xattr.go
@@ -2,6 +2,7 @@ package meta
 
 import (
 	"errors"
+	"fmt"
 	"path/filepath"
 	"strings"
 	"syscall"
@@ -23,7 +24,7 @@ type XattrMeta struct{}
 // RetrieveAttribute retrieves the value of a specific attribute for an object in a bucket.
 func (x XattrMeta) RetrieveAttribute(bucket, object, attribute string) ([]byte, error) {
 	b, err := xattr.Get(filepath.Join(bucket, object), xattrPrefix+attribute)
-	if errors.Is(err, errNoData) {
+	if errors.Is(err, xattr.ENOATTR) {
 		return nil, ErrNoSuchKey
 	}
 	return b, err
@@ -37,7 +38,7 @@ func (x XattrMeta) StoreAttribute(bucket, object, attribute string, value []byte
 // DeleteAttribute removes the value of a specific attribute for an object in a bucket.
 func (x XattrMeta) DeleteAttribute(bucket, object, attribute string) error {
 	err := xattr.Remove(filepath.Join(bucket, object), xattrPrefix+attribute)
-	if errors.Is(err, errNoData) {
+	if errors.Is(err, xattr.ENOATTR) {
 		return ErrNoSuchKey
 	}
 	return err
@@ -70,7 +71,17 @@ func isUserAttr(attr string) bool {
 }
 
 // Test is a helper function to test if xattrs are supported.
-func (x XattrMeta) Test(path string) bool {
+func (x XattrMeta) Test(path string) error {
+	// check for platform support
+	if !xattr.XATTR_SUPPORTED {
+		return fmt.Errorf("xattrs are not supported on this platform")
+	}
+
+	// check if the filesystem supports xattrs
 	_, err := xattr.Get(path, "user.test")
-	return !errors.Is(err, syscall.ENOTSUP)
+	if errors.Is(err, syscall.ENOTSUP) {
+		return fmt.Errorf("xattrs are not supported on this filesystem")
+	}
+
+	return nil
 }
diff --git a/backend/meta/xattr_with_enodata.go b/backend/meta/xattr_with_enodata.go
deleted file mode 100644
index e492a7b..0000000
--- a/backend/meta/xattr_with_enodata.go
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2024 Versity Software
-// This file is licensed 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.
-
-//go:build !freebsd && !openbsd && !netbsd
-// +build !freebsd,!openbsd,!netbsd
-
-package meta
-
-import "syscall"
-
-var (
-	errNoData = syscall.ENODATA
-)
diff --git a/backend/meta/xattr_without_enodata.go b/backend/meta/xattr_without_enodata.go
deleted file mode 100644
index 706e188..0000000
--- a/backend/meta/xattr_without_enodata.go
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2024 Versity Software
-// This file is licensed 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.
-
-//go:build freebsd || openbsd || netbsd
-// +build freebsd openbsd netbsd
-
-package meta
-
-import "syscall"
-
-var (
-	errNoData = syscall.ENOATTR
-)
diff --git a/cmd/versitygw/posix.go b/cmd/versitygw/posix.go
index be0167b..9d234c8 100644
--- a/cmd/versitygw/posix.go
+++ b/cmd/versitygw/posix.go
@@ -64,9 +64,9 @@ func runPosix(ctx *cli.Context) error {
 	}
 
 	gwroot := (ctx.Args().Get(0))
-	ok := meta.XattrMeta{}.Test(gwroot)
-	if !ok {
-		return fmt.Errorf("posix backend requires extended attributes support")
+	err := meta.XattrMeta{}.Test(gwroot)
+	if err != nil {
+		return fmt.Errorf("posix xattr check: %v", err)
 	}
 
 	be, err := posix.New(gwroot, meta.XattrMeta{}, posix.PosixOpts{