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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build windows
// Package registry provides access to the Windows registry.
//
// Here is a simple example, opening a registry key and reading a string value from it.
//
// k, err := registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\Microsoft\Windows NT\CurrentVersion`, registry.QUERY_VALUE)
// if err != nil {
// log.Fatal(err)
// }
// defer k.Close()
//
// s, _, err := k.GetStringValue("SystemRoot")
// if err != nil {
// log.Fatal(err)
// }
// fmt.Printf("Windows system root is %q\n", s)
//
package registry
import (
"io"
"syscall"
"time"
)
const (
// Registry key security and access rights.
// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms724878.aspx
// for details.
ALL_ACCESS = 0xf003f
CREATE_LINK = 0x00020
CREATE_SUB_KEY = 0x00004
ENUMERATE_SUB_KEYS = 0x00008
EXECUTE = 0x20019
NOTIFY = 0x00010
QUERY_VALUE = 0x00001
READ = 0x20019
SET_VALUE = 0x00002
WOW64_32KEY = 0x00200
WOW64_64KEY = 0x00100
WRITE = 0x20006
)
// Key is a handle to an open Windows registry key.
// Keys can be obtained by calling OpenKey; there are
// also some predefined root keys such as CURRENT_USER.
// Keys can be used directly in the Windows API.
type Key syscall.Handle
const (
// Windows defines some predefined root keys that are always open.
// An application can use these keys as entry points to the registry.
// Normally these keys are used in OpenKey to open new keys,
// but they can also be used anywhere a Key is required.
CLASSES_ROOT = Key(syscall.HKEY_CLASSES_ROOT)
CURRENT_USER = Key(syscall.HKEY_CURRENT_USER)
LOCAL_MACHINE = Key(syscall.HKEY_LOCAL_MACHINE)
USERS = Key(syscall.HKEY_USERS)
CURRENT_CONFIG = Key(syscall.HKEY_CURRENT_CONFIG)
PERFORMANCE_DATA = Key(syscall.HKEY_PERFORMANCE_DATA)
)
// Close closes open key k.
func (k Key) Close() error {
return syscall.RegCloseKey(syscall.Handle(k))
}
// OpenKey opens a new key with path name relative to key k.
// It accepts any open key, including CURRENT_USER and others,
// and returns the new key and an error.
// The access parameter specifies desired access rights to the
// key to be opened.
func OpenKey(k Key, path string, access uint32) (Key, error) {
p, err := syscall.UTF16PtrFromString(path)
if err != nil {
return 0, err
}
var subkey syscall.Handle
err = syscall.RegOpenKeyEx(syscall.Handle(k), p, 0, access, &subkey)
if err != nil {
return 0, err
}
return Key(subkey), nil
}
// OpenRemoteKey opens a predefined registry key on another
// computer pcname. The key to be opened is specified by k, but
// can only be one of LOCAL_MACHINE, PERFORMANCE_DATA or USERS.
// If pcname is "", OpenRemoteKey returns local computer key.
func OpenRemoteKey(pcname string, k Key) (Key, error) {
var err error
var p *uint16
if pcname != "" {
p, err = syscall.UTF16PtrFromString(`\\` + pcname)
if err != nil {
return 0, err
}
}
var remoteKey syscall.Handle
err = regConnectRegistry(p, syscall.Handle(k), &remoteKey)
if err != nil {
return 0, err
}
return Key(remoteKey), nil
}
// ReadSubKeyNames returns the names of subkeys of key k.
// The parameter n controls the number of returned names,
// analogous to the way os.File.Readdirnames works.
func (k Key) ReadSubKeyNames(n int) ([]string, error) {
names := make([]string, 0)
// Registry key size limit is 255 bytes and described there:
// https://msdn.microsoft.com/library/windows/desktop/ms724872.aspx
buf := make([]uint16, 256) //plus extra room for terminating zero byte
loopItems:
for i := uint32(0); ; i++ {
if n > 0 {
if len(names) == n {
return names, nil
}
}
l := uint32(len(buf))
for {
err := syscall.RegEnumKeyEx(syscall.Handle(k), i, &buf[0], &l, nil, nil, nil, nil)
if err == nil {
break
}
if err == syscall.ERROR_MORE_DATA {
// Double buffer size and try again.
l = uint32(2 * len(buf))
buf = make([]uint16, l)
continue
}
if err == _ERROR_NO_MORE_ITEMS {
break loopItems
}
return names, err
}
names = append(names, syscall.UTF16ToString(buf[:l]))
}
if n > len(names) {
return names, io.EOF
}
return names, nil
}
// CreateKey creates a key named path under open key k.
// CreateKey returns the new key and a boolean flag that reports
// whether the key already existed.
// The access parameter specifies the access rights for the key
// to be created.
func CreateKey(k Key, path string, access uint32) (newk Key, openedExisting bool, err error) {
var h syscall.Handle
var d uint32
err = regCreateKeyEx(syscall.Handle(k), syscall.StringToUTF16Ptr(path),
0, nil, _REG_OPTION_NON_VOLATILE, access, nil, &h, &d)
if err != nil {
return 0, false, err
}
return Key(h), d == _REG_OPENED_EXISTING_KEY, nil
}
// DeleteKey deletes the subkey path of key k and its values.
func DeleteKey(k Key, path string) error {
return regDeleteKey(syscall.Handle(k), syscall.StringToUTF16Ptr(path))
}
// A KeyInfo describes the statistics of a key. It is returned by Stat.
type KeyInfo struct {
SubKeyCount uint32
MaxSubKeyLen uint32 // size of the key's subkey with the longest name, in Unicode characters, not including the terminating zero byte
ValueCount uint32
MaxValueNameLen uint32 // size of the key's longest value name, in Unicode characters, not including the terminating zero byte
MaxValueLen uint32 // longest data component among the key's values, in bytes
lastWriteTime syscall.Filetime
}
// ModTime returns the key's last write time.
func (ki *KeyInfo) ModTime() time.Time {
return time.Unix(0, ki.lastWriteTime.Nanoseconds())
}
// Stat retrieves information about the open key k.
func (k Key) Stat() (*KeyInfo, error) {
var ki KeyInfo
err := syscall.RegQueryInfoKey(syscall.Handle(k), nil, nil, nil,
&ki.SubKeyCount, &ki.MaxSubKeyLen, nil, &ki.ValueCount,
&ki.MaxValueNameLen, &ki.MaxValueLen, nil, &ki.lastWriteTime)
if err != nil {
return nil, err
}
return &ki, nil
}