syncthing/lib/fs/basicfs_xattr_linuxish.go

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// Copyright (C) 2022 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
//go:build linux || darwin
// +build linux darwin
package fs
import (
"errors"
"fmt"
"sort"
"strings"
"golang.org/x/sys/unix"
)
func listXattr(path string) ([]string, error) {
buf := make([]byte, 1024)
size, err := unix.Llistxattr(path, buf)
if errors.Is(err, unix.ERANGE) {
// Buffer is too small. Try again with a zero sized buffer to get
// the size, then allocate a buffer of the correct size.
size, err = unix.Llistxattr(path, nil)
if err != nil {
return nil, fmt.Errorf("Listxattr %s: %w", path, err)
}
buf = make([]byte, size)
size, err = unix.Llistxattr(path, buf)
}
if err != nil {
return nil, fmt.Errorf("Listxattr %s: %w", path, err)
}
buf = buf[:size]
attrs := compact(strings.Split(string(buf), "\x00"))
sort.Strings(attrs)
return attrs, nil
}