syncthing/lib/fs/basicfs_platformdata_windows.go
Jakob Borg adce6fa473
all: Support syncing ownership (fixes #1329) (#8434)
This adds support for syncing ownership on Unixes and on Windows. The
scanner always picks up ownership information, but it is not applied
unless the new folder option "Sync Ownership" is set.

Ownership data is stored in a new FileInfo field called "platform data". This
is intended to hold further platform-specific data in the future
(specifically, extended attributes), which is why the whole design is a
bit overkill for just ownership.
2022-07-26 08:24:58 +02:00

70 lines
2.4 KiB
Go

// 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/.
package fs
import (
"fmt"
"os/user"
"github.com/syncthing/syncthing/lib/protocol"
"golang.org/x/sys/windows"
)
func (f *BasicFilesystem) PlatformData(name string) (protocol.PlatformData, error) {
rootedName, err := f.rooted(name)
if err != nil {
return protocol.PlatformData{}, fmt.Errorf("rooted for %s: %w", name, err)
}
hdl, err := openReadOnlyWithBackupSemantics(rootedName)
if err != nil {
return protocol.PlatformData{}, fmt.Errorf("open %s: %w", rootedName, err)
}
defer windows.Close(hdl)
// GetSecurityInfo returns an owner SID.
sd, err := windows.GetSecurityInfo(hdl, windows.SE_FILE_OBJECT, windows.OWNER_SECURITY_INFORMATION)
if err != nil {
return protocol.PlatformData{}, fmt.Errorf("get security info for %s: %w", rootedName, err)
}
owner, _, err := sd.Owner()
if err != nil {
return protocol.PlatformData{}, fmt.Errorf("get owner for %s: %w", rootedName, err)
}
// The owner SID might represent a user or a group. We try to look it up
// as both, and set the appropriate fields in the OS data.
pd := &protocol.WindowsData{}
if us, err := user.LookupId(owner.String()); err == nil {
pd.OwnerName = us.Username
} else if gr, err := user.LookupGroupId(owner.String()); err == nil {
pd.OwnerName = gr.Name
pd.OwnerIsGroup = true
} else {
l.Debugf("Failed to resolve owner for %s: %v", rootedName, err)
}
return protocol.PlatformData{Windows: pd}, nil
}
func openReadOnlyWithBackupSemantics(path string) (fd windows.Handle, err error) {
// This is windows.Open but simplified to read-only only, and adding
// FILE_FLAG_BACKUP_SEMANTICS which is required to open directories.
if len(path) == 0 {
return windows.InvalidHandle, windows.ERROR_FILE_NOT_FOUND
}
pathp, err := windows.UTF16PtrFromString(path)
if err != nil {
return windows.InvalidHandle, err
}
var access uint32 = windows.GENERIC_READ
var sharemode uint32 = windows.FILE_SHARE_READ | windows.FILE_SHARE_WRITE
var sa *windows.SecurityAttributes
var createmode uint32 = windows.OPEN_EXISTING
var attrs uint32 = windows.FILE_ATTRIBUTE_READONLY | windows.FILE_FLAG_BACKUP_SEMANTICS
return windows.CreateFile(pathp, access, sharemode, sa, createmode, attrs, 0)
}