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77 lines
2.1 KiB
Go
77 lines
2.1 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//
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// The code in this file originates from https://git.zx2c4.com/wireguard-go:
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// Copyright (C) 2017-2020 WireGuard LLC. All Rights Reserved.
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// Copying license: https://git.zx2c4.com/wireguard-go/tree/COPYING
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package dns
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import (
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"fmt"
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"runtime"
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"strings"
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"time"
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"golang.org/x/sys/windows"
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"golang.org/x/sys/windows/registry"
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)
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func openKeyWait(k registry.Key, path string, access uint32, timeout time.Duration) (registry.Key, error) {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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deadline := time.Now().Add(timeout)
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pathSpl := strings.Split(path, "\\")
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for i := 0; ; i++ {
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keyName := pathSpl[i]
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isLast := i+1 == len(pathSpl)
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event, err := windows.CreateEvent(nil, 0, 0, nil)
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if err != nil {
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return 0, fmt.Errorf("windows.CreateEvent: %v", err)
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}
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defer windows.CloseHandle(event)
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var key registry.Key
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for {
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err = windows.RegNotifyChangeKeyValue(windows.Handle(k), false, windows.REG_NOTIFY_CHANGE_NAME, event, true)
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if err != nil {
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return 0, fmt.Errorf("windows.RegNotifyChangeKeyValue: %v", err)
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}
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var accessFlags uint32
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if isLast {
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accessFlags = access
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} else {
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accessFlags = registry.NOTIFY
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}
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key, err = registry.OpenKey(k, keyName, accessFlags)
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if err == windows.ERROR_FILE_NOT_FOUND || err == windows.ERROR_PATH_NOT_FOUND {
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timeout := time.Until(deadline) / time.Millisecond
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if timeout < 0 {
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timeout = 0
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}
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s, err := windows.WaitForSingleObject(event, uint32(timeout))
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if err != nil {
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return 0, fmt.Errorf("windows.WaitForSingleObject: %v", err)
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}
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if s == uint32(windows.WAIT_TIMEOUT) { // windows.WAIT_TIMEOUT status const is misclassified as error in golang.org/x/sys/windows
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return 0, fmt.Errorf("timeout waiting for registry key")
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}
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} else if err != nil {
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return 0, fmt.Errorf("registry.OpenKey(%v): %v", path, err)
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} else {
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if isLast {
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return key, nil
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}
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defer key.Close()
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break
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}
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}
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k = key
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}
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}
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