1// Copyright 2015 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// +build windows
6
7// Package registry provides access to the Windows registry.
8//
9// Here is a simple example, opening a registry key and reading a string value from it.
10//
11//	k, err := registry.OpenKey(registry.LOCAL_MACHINE, `SOFTWARE\Microsoft\Windows NT\CurrentVersion`, registry.QUERY_VALUE)
12//	if err != nil {
13//		log.Fatal(err)
14//	}
15//	defer k.Close()
16//
17//	s, _, err := k.GetStringValue("SystemRoot")
18//	if err != nil {
19//		log.Fatal(err)
20//	}
21//	fmt.Printf("Windows system root is %q\n", s)
22//
23// NOTE: This package is a copy of golang.org/x/sys/windows/registry
24// with KeyInfo.ModTime removed to prevent dependency cycles.
25//
26package registry
27
28import "syscall"
29
30const (
31	// Registry key security and access rights.
32	// See https://msdn.microsoft.com/en-us/library/windows/desktop/ms724878.aspx
33	// for details.
34	ALL_ACCESS         = 0xf003f
35	CREATE_LINK        = 0x00020
36	CREATE_SUB_KEY     = 0x00004
37	ENUMERATE_SUB_KEYS = 0x00008
38	EXECUTE            = 0x20019
39	NOTIFY             = 0x00010
40	QUERY_VALUE        = 0x00001
41	READ               = 0x20019
42	SET_VALUE          = 0x00002
43	WOW64_32KEY        = 0x00200
44	WOW64_64KEY        = 0x00100
45	WRITE              = 0x20006
46)
47
48// Key is a handle to an open Windows registry key.
49// Keys can be obtained by calling OpenKey; there are
50// also some predefined root keys such as CURRENT_USER.
51// Keys can be used directly in the Windows API.
52type Key syscall.Handle
53
54const (
55	// Windows defines some predefined root keys that are always open.
56	// An application can use these keys as entry points to the registry.
57	// Normally these keys are used in OpenKey to open new keys,
58	// but they can also be used anywhere a Key is required.
59	CLASSES_ROOT   = Key(syscall.HKEY_CLASSES_ROOT)
60	CURRENT_USER   = Key(syscall.HKEY_CURRENT_USER)
61	LOCAL_MACHINE  = Key(syscall.HKEY_LOCAL_MACHINE)
62	USERS          = Key(syscall.HKEY_USERS)
63	CURRENT_CONFIG = Key(syscall.HKEY_CURRENT_CONFIG)
64)
65
66// Close closes open key k.
67func (k Key) Close() error {
68	return syscall.RegCloseKey(syscall.Handle(k))
69}
70
71// OpenKey opens a new key with path name relative to key k.
72// It accepts any open key, including CURRENT_USER and others,
73// and returns the new key and an error.
74// The access parameter specifies desired access rights to the
75// key to be opened.
76func OpenKey(k Key, path string, access uint32) (Key, error) {
77	p, err := syscall.UTF16PtrFromString(path)
78	if err != nil {
79		return 0, err
80	}
81	var subkey syscall.Handle
82	err = syscall.RegOpenKeyEx(syscall.Handle(k), p, 0, access, &subkey)
83	if err != nil {
84		return 0, err
85	}
86	return Key(subkey), nil
87}
88
89// ReadSubKeyNames returns the names of subkeys of key k.
90func (k Key) ReadSubKeyNames() ([]string, error) {
91	names := make([]string, 0)
92	// Registry key size limit is 255 bytes and described there:
93	// https://msdn.microsoft.com/library/windows/desktop/ms724872.aspx
94	buf := make([]uint16, 256) //plus extra room for terminating zero byte
95loopItems:
96	for i := uint32(0); ; i++ {
97		l := uint32(len(buf))
98		for {
99			err := syscall.RegEnumKeyEx(syscall.Handle(k), i, &buf[0], &l, nil, nil, nil, nil)
100			if err == nil {
101				break
102			}
103			if err == syscall.ERROR_MORE_DATA {
104				// Double buffer size and try again.
105				l = uint32(2 * len(buf))
106				buf = make([]uint16, l)
107				continue
108			}
109			if err == _ERROR_NO_MORE_ITEMS {
110				break loopItems
111			}
112			return names, err
113		}
114		names = append(names, syscall.UTF16ToString(buf[:l]))
115	}
116	return names, nil
117}
118
119// CreateKey creates a key named path under open key k.
120// CreateKey returns the new key and a boolean flag that reports
121// whether the key already existed.
122// The access parameter specifies the access rights for the key
123// to be created.
124func CreateKey(k Key, path string, access uint32) (newk Key, openedExisting bool, err error) {
125	var h syscall.Handle
126	var d uint32
127	err = regCreateKeyEx(syscall.Handle(k), syscall.StringToUTF16Ptr(path),
128		0, nil, _REG_OPTION_NON_VOLATILE, access, nil, &h, &d)
129	if err != nil {
130		return 0, false, err
131	}
132	return Key(h), d == _REG_OPENED_EXISTING_KEY, nil
133}
134
135// DeleteKey deletes the subkey path of key k and its values.
136func DeleteKey(k Key, path string) error {
137	return regDeleteKey(syscall.Handle(k), syscall.StringToUTF16Ptr(path))
138}
139
140// A KeyInfo describes the statistics of a key. It is returned by Stat.
141type KeyInfo struct {
142	SubKeyCount     uint32
143	MaxSubKeyLen    uint32 // size of the key's subkey with the longest name, in Unicode characters, not including the terminating zero byte
144	ValueCount      uint32
145	MaxValueNameLen uint32 // size of the key's longest value name, in Unicode characters, not including the terminating zero byte
146	MaxValueLen     uint32 // longest data component among the key's values, in bytes
147	lastWriteTime   syscall.Filetime
148}
149
150// Stat retrieves information about the open key k.
151func (k Key) Stat() (*KeyInfo, error) {
152	var ki KeyInfo
153	err := syscall.RegQueryInfoKey(syscall.Handle(k), nil, nil, nil,
154		&ki.SubKeyCount, &ki.MaxSubKeyLen, nil, &ki.ValueCount,
155		&ki.MaxValueNameLen, &ki.MaxValueLen, nil, &ki.lastWriteTime)
156	if err != nil {
157		return nil, err
158	}
159	return &ki, nil
160}
161