wintun: wait for interface registry key on device creation
By using RegNotifyChangeKeyValue(). Also disable dead gateway detection. Signed-off-by: Simon Rozman <simon@rozman.si>
This commit is contained in:
Simon Rozman
committed by
Jason A. Donenfeld
Jason A. Donenfeld
parent
586112b5d7
commit
7e962a9932
240
tun/wintun/registry/registry_windows.go
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240
tun/wintun/registry/registry_windows.go
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@@ -0,0 +1,240 @@
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/* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
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*/
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package registry
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import (
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"errors"
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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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const (
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KEY_NOTIFY uint32 = 0x0010 // should be defined upstream as registry.KEY_NOTIFY
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)
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const (
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// REG_NOTIFY_CHANGE_NAME notifies the caller if a subkey is added or deleted.
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REG_NOTIFY_CHANGE_NAME uint32 = 0x00000001
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// REG_NOTIFY_CHANGE_ATTRIBUTES notifies the caller of changes to the attributes of the key, such as the security descriptor information.
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REG_NOTIFY_CHANGE_ATTRIBUTES uint32 = 0x00000002
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// REG_NOTIFY_CHANGE_LAST_SET notifies the caller of changes to a value of the key. This can include adding or deleting a value, or changing an existing value.
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REG_NOTIFY_CHANGE_LAST_SET uint32 = 0x00000004
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// REG_NOTIFY_CHANGE_SECURITY notifies the caller of changes to the security descriptor of the key.
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REG_NOTIFY_CHANGE_SECURITY uint32 = 0x00000008
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// REG_NOTIFY_THREAD_AGNOSTIC indicates that the lifetime of the registration must not be tied to the lifetime of the thread issuing the RegNotifyChangeKeyValue call. Note: This flag value is only supported in Windows 8 and later.
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REG_NOTIFY_THREAD_AGNOSTIC uint32 = 0x10000000
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)
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//sys regNotifyChangeKeyValue(key windows.Handle, watchSubtree bool, notifyFilter uint32, event windows.Handle, asynchronous bool) (regerrno error) = advapi32.RegNotifyChangeKeyValue
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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("Error creating event: %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 = regNotifyChangeKeyValue(windows.Handle(k), false, REG_NOTIFY_CHANGE_NAME, windows.Handle(event), true)
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if err != nil {
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return 0, fmt.Errorf("Setting up change notification on registry key failed: %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 = KEY_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("Unable to wait on registry key: %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, errors.New("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("Error opening registry key %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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func WaitForKey(k registry.Key, path string, timeout time.Duration) error {
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key, err := OpenKeyWait(k, path, KEY_NOTIFY, timeout)
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if err != nil {
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return err
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}
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key.Close()
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return nil
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}
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//
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// getStringValueRetry function reads a string value from registry. It waits for
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// the registry value to become available or returns error on timeout.
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//
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// Key must be opened with at least QUERY_VALUE|KEY_NOTIFY access.
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//
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func getStringValueRetry(key registry.Key, name string, timeout time.Duration) (string, uint32, error) {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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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("Error creating event: %v", err)
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}
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defer windows.CloseHandle(event)
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deadline := time.Now().Add(timeout)
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for {
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err := regNotifyChangeKeyValue(windows.Handle(key), false, REG_NOTIFY_CHANGE_LAST_SET, windows.Handle(event), true)
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if err != nil {
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return "", 0, fmt.Errorf("Setting up change notification on registry value failed: %v", err)
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}
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value, valueType, err := key.GetStringValue(name)
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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("Unable to wait on registry value: %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, errors.New("Timeout waiting for registry value")
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}
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} else if err != nil {
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return "", 0, fmt.Errorf("Error reading registry value %v: %v", name, err)
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} else {
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return value, valueType, nil
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}
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}
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}
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func expandString(value string, valueType uint32, err error) (string, error) {
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if err != nil {
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return "", err
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}
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if valueType != registry.EXPAND_SZ {
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// Value does not require expansion.
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return value, nil
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}
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valueExp, err := registry.ExpandString(value)
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if err != nil {
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// Expanding failed: return original sting value.
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return value, nil
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}
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// Return expanded value.
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return valueExp, nil
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}
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//
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// GetStringValueWait function reads a string value from registry. It waits
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// for the registry value to become available or returns error on timeout.
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//
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// Key must be opened with at least QUERY_VALUE|KEY_NOTIFY access.
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//
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// If the value type is REG_EXPAND_SZ the environment variables are expanded.
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// Should expanding fail, original string value and nil error are returned.
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//
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func GetStringValueWait(key registry.Key, name string, timeout time.Duration) (string, error) {
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return expandString(getStringValueRetry(key, name, timeout))
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}
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//
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// GetStringValue function reads a string value from registry.
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//
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// Key must be opened with at least QUERY_VALUE access.
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//
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// If the value type is REG_EXPAND_SZ the environment variables are expanded.
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// Should expanding fail, original string value and nil error are returned.
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//
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func GetStringValue(key registry.Key, name string) (string, error) {
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return expandString(key.GetStringValue(name))
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}
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//
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// GetIntegerValueWait function reads a DWORD32 or QWORD value from registry.
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// It waits for the registry value to become available or returns error on
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// timeout.
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//
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// Key must be opened with at least QUERY_VALUE|KEY_NOTIFY access.
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//
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func GetIntegerValueWait(key registry.Key, name string, timeout time.Duration) (uint64, error) {
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runtime.LockOSThread()
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defer runtime.UnlockOSThread()
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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("Error creating event: %v", err)
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}
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defer windows.CloseHandle(event)
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deadline := time.Now().Add(timeout)
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for {
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err := regNotifyChangeKeyValue(windows.Handle(key), false, REG_NOTIFY_CHANGE_LAST_SET, windows.Handle(event), true)
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if err != nil {
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return 0, fmt.Errorf("Setting up change notification on registry value failed: %v", err)
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}
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value, _, err := key.GetIntegerValue(name)
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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("Unable to wait on registry value: %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, errors.New("Timeout waiting for registry value")
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}
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} else if err != nil {
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return 0, fmt.Errorf("Error reading registry value %v: %v", name, err)
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} else {
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return value, nil
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}
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}
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}
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