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 //go:build windows
6 7 package registry
8 9 import (
10 "errors"
11 "io"
12 "syscall"
13 "unicode/utf16"
14 "unsafe"
15 )
16 17 const (
18 // Registry value types.
19 NONE = 0
20 SZ = 1
21 EXPAND_SZ = 2
22 BINARY = 3
23 DWORD = 4
24 DWORD_BIG_ENDIAN = 5
25 LINK = 6
26 MULTI_SZ = 7
27 RESOURCE_LIST = 8
28 FULL_RESOURCE_DESCRIPTOR = 9
29 RESOURCE_REQUIREMENTS_LIST = 10
30 QWORD = 11
31 )
32 33 var (
34 // ErrShortBuffer is returned when the buffer was too short for the operation.
35 ErrShortBuffer = syscall.ERROR_MORE_DATA
36 37 // ErrNotExist is returned when a registry key or value does not exist.
38 ErrNotExist = syscall.ERROR_FILE_NOT_FOUND
39 40 // ErrUnexpectedType is returned by Get*Value when the value's type was unexpected.
41 ErrUnexpectedType = errors.New("unexpected key value type")
42 )
43 44 // GetValue retrieves the type and data for the specified value associated
45 // with an open key k. It fills up buffer buf and returns the retrieved
46 // byte count n. If buf is too small to fit the stored value it returns
47 // ErrShortBuffer error along with the required buffer size n.
48 // If no buffer is provided, it returns true and actual buffer size n.
49 // If no buffer is provided, GetValue returns the value's type only.
50 // If the value does not exist, the error returned is ErrNotExist.
51 //
52 // GetValue is a low level function. If value's type is known, use the appropriate
53 // Get*Value function instead.
54 func (k Key) GetValue(name string, buf []byte) (n int, valtype uint32, err error) {
55 pname, err := syscall.UTF16PtrFromString(name)
56 if err != nil {
57 return 0, 0, err
58 }
59 var pbuf *byte
60 if len(buf) > 0 {
61 pbuf = (*byte)(unsafe.Pointer(&buf[0]))
62 }
63 l := uint32(len(buf))
64 err = syscall.RegQueryValueEx(syscall.Handle(k), pname, nil, &valtype, pbuf, &l)
65 if err != nil {
66 return int(l), valtype, err
67 }
68 return int(l), valtype, nil
69 }
70 71 func (k Key) getValue(name string, buf []byte) (data []byte, valtype uint32, err error) {
72 p, err := syscall.UTF16PtrFromString(name)
73 if err != nil {
74 return nil, 0, err
75 }
76 var t uint32
77 n := uint32(len(buf))
78 for {
79 err = syscall.RegQueryValueEx(syscall.Handle(k), p, nil, &t, (*byte)(unsafe.Pointer(&buf[0])), &n)
80 if err == nil {
81 return buf[:n], t, nil
82 }
83 if err != syscall.ERROR_MORE_DATA {
84 return nil, 0, err
85 }
86 if n <= uint32(len(buf)) {
87 return nil, 0, err
88 }
89 buf = make([]byte, n)
90 }
91 }
92 93 // GetStringValue retrieves the string value for the specified
94 // value name associated with an open key k. It also returns the value's type.
95 // If value does not exist, GetStringValue returns ErrNotExist.
96 // If value is not SZ or EXPAND_SZ, it will return the correct value
97 // type and ErrUnexpectedType.
98 func (k Key) GetStringValue(name string) (val string, valtype uint32, err error) {
99 data, typ, err2 := k.getValue(name, make([]byte, 64))
100 if err2 != nil {
101 return "", typ, err2
102 }
103 switch typ {
104 case SZ, EXPAND_SZ:
105 default:
106 return "", typ, ErrUnexpectedType
107 }
108 if len(data) == 0 {
109 return "", typ, nil
110 }
111 u := (*[1 << 29]uint16)(unsafe.Pointer(&data[0]))[: len(data)/2 : len(data)/2]
112 return syscall.UTF16ToString(u), typ, nil
113 }
114 115 // GetMUIStringValue retrieves the localized string value for
116 // the specified value name associated with an open key k.
117 // If the value name doesn't exist or the localized string value
118 // can't be resolved, GetMUIStringValue returns ErrNotExist.
119 // GetMUIStringValue panics if the system doesn't support
120 // regLoadMUIString; use LoadRegLoadMUIString to check if
121 // regLoadMUIString is supported before calling this function.
122 func (k Key) GetMUIStringValue(name string) (string, error) {
123 pname, err := syscall.UTF16PtrFromString(name)
124 if err != nil {
125 return "", err
126 }
127 128 buf := make([]uint16, 1024)
129 var buflen uint32
130 var pdir *uint16
131 132 err = regLoadMUIString(syscall.Handle(k), pname, &buf[0], uint32(len(buf)), &buflen, 0, pdir)
133 if err == syscall.ERROR_FILE_NOT_FOUND { // Try fallback path
134 135 // Try to resolve the string value using the system directory as
136 // a DLL search path; this assumes the string value is of the form
137 // @[path]\dllname,-strID but with no path given, e.g. @tzres.dll,-320.
138 139 // This approach works with tzres.dll but may have to be revised
140 // in the future to allow callers to provide custom search paths.
141 142 var s string
143 s, err = ExpandString("%SystemRoot%\\system32\\")
144 if err != nil {
145 return "", err
146 }
147 pdir, err = syscall.UTF16PtrFromString(s)
148 if err != nil {
149 return "", err
150 }
151 152 err = regLoadMUIString(syscall.Handle(k), pname, &buf[0], uint32(len(buf)), &buflen, 0, pdir)
153 }
154 155 for err == syscall.ERROR_MORE_DATA { // Grow buffer if needed
156 if buflen <= uint32(len(buf)) {
157 break // Buffer not growing, assume race; break
158 }
159 buf = make([]uint16, buflen)
160 err = regLoadMUIString(syscall.Handle(k), pname, &buf[0], uint32(len(buf)), &buflen, 0, pdir)
161 }
162 163 if err != nil {
164 return "", err
165 }
166 167 return syscall.UTF16ToString(buf), nil
168 }
169 170 // ExpandString expands environment-variable strings and replaces
171 // them with the values defined for the current user.
172 // Use ExpandString to expand EXPAND_SZ strings.
173 func ExpandString(value string) (string, error) {
174 if value == "" {
175 return "", nil
176 }
177 p, err := syscall.UTF16PtrFromString(value)
178 if err != nil {
179 return "", err
180 }
181 r := make([]uint16, 100)
182 for {
183 n, err := expandEnvironmentStrings(p, &r[0], uint32(len(r)))
184 if err != nil {
185 return "", err
186 }
187 if n <= uint32(len(r)) {
188 return syscall.UTF16ToString(r[:n]), nil
189 }
190 r = make([]uint16, n)
191 }
192 }
193 194 // GetStringsValue retrieves the []string value for the specified
195 // value name associated with an open key k. It also returns the value's type.
196 // If value does not exist, GetStringsValue returns ErrNotExist.
197 // If value is not MULTI_SZ, it will return the correct value
198 // type and ErrUnexpectedType.
199 func (k Key) GetStringsValue(name string) (val []string, valtype uint32, err error) {
200 data, typ, err2 := k.getValue(name, make([]byte, 64))
201 if err2 != nil {
202 return nil, typ, err2
203 }
204 if typ != MULTI_SZ {
205 return nil, typ, ErrUnexpectedType
206 }
207 if len(data) == 0 {
208 return nil, typ, nil
209 }
210 p := (*[1 << 29]uint16)(unsafe.Pointer(&data[0]))[: len(data)/2 : len(data)/2]
211 if len(p) == 0 {
212 return nil, typ, nil
213 }
214 if p[len(p)-1] == 0 {
215 p = p[:len(p)-1] // remove terminating null
216 }
217 val = make([]string, 0, 5)
218 from := 0
219 for i, c := range p {
220 if c == 0 {
221 val = append(val, string(utf16.Decode(p[from:i])))
222 from = i + 1
223 }
224 }
225 return val, typ, nil
226 }
227 228 // GetIntegerValue retrieves the integer value for the specified
229 // value name associated with an open key k. It also returns the value's type.
230 // If value does not exist, GetIntegerValue returns ErrNotExist.
231 // If value is not DWORD or QWORD, it will return the correct value
232 // type and ErrUnexpectedType.
233 func (k Key) GetIntegerValue(name string) (val uint64, valtype uint32, err error) {
234 data, typ, err2 := k.getValue(name, make([]byte, 8))
235 if err2 != nil {
236 return 0, typ, err2
237 }
238 switch typ {
239 case DWORD:
240 if len(data) != 4 {
241 return 0, typ, errors.New("DWORD value is not 4 bytes long")
242 }
243 var val32 uint32
244 copy((*[4]byte)(unsafe.Pointer(&val32))[:], data)
245 return uint64(val32), DWORD, nil
246 case QWORD:
247 if len(data) != 8 {
248 return 0, typ, errors.New("QWORD value is not 8 bytes long")
249 }
250 copy((*[8]byte)(unsafe.Pointer(&val))[:], data)
251 return val, QWORD, nil
252 default:
253 return 0, typ, ErrUnexpectedType
254 }
255 }
256 257 // GetBinaryValue retrieves the binary value for the specified
258 // value name associated with an open key k. It also returns the value's type.
259 // If value does not exist, GetBinaryValue returns ErrNotExist.
260 // If value is not BINARY, it will return the correct value
261 // type and ErrUnexpectedType.
262 func (k Key) GetBinaryValue(name string) (val []byte, valtype uint32, err error) {
263 data, typ, err2 := k.getValue(name, make([]byte, 64))
264 if err2 != nil {
265 return nil, typ, err2
266 }
267 if typ != BINARY {
268 return nil, typ, ErrUnexpectedType
269 }
270 return data, typ, nil
271 }
272 273 func (k Key) setValue(name string, valtype uint32, data []byte) error {
274 p, err := syscall.UTF16PtrFromString(name)
275 if err != nil {
276 return err
277 }
278 if len(data) == 0 {
279 return regSetValueEx(syscall.Handle(k), p, 0, valtype, nil, 0)
280 }
281 return regSetValueEx(syscall.Handle(k), p, 0, valtype, &data[0], uint32(len(data)))
282 }
283 284 // SetDWordValue sets the data and type of a name value
285 // under key k to value and DWORD.
286 func (k Key) SetDWordValue(name string, value uint32) error {
287 return k.setValue(name, DWORD, (*[4]byte)(unsafe.Pointer(&value))[:])
288 }
289 290 // SetQWordValue sets the data and type of a name value
291 // under key k to value and QWORD.
292 func (k Key) SetQWordValue(name string, value uint64) error {
293 return k.setValue(name, QWORD, (*[8]byte)(unsafe.Pointer(&value))[:])
294 }
295 296 func (k Key) setStringValue(name string, valtype uint32, value string) error {
297 v, err := syscall.UTF16FromString(value)
298 if err != nil {
299 return err
300 }
301 buf := (*[1 << 29]byte)(unsafe.Pointer(&v[0]))[: len(v)*2 : len(v)*2]
302 return k.setValue(name, valtype, buf)
303 }
304 305 // SetStringValue sets the data and type of a name value
306 // under key k to value and SZ. The value must not contain a zero byte.
307 func (k Key) SetStringValue(name, value string) error {
308 return k.setStringValue(name, SZ, value)
309 }
310 311 // SetExpandStringValue sets the data and type of a name value
312 // under key k to value and EXPAND_SZ. The value must not contain a zero byte.
313 func (k Key) SetExpandStringValue(name, value string) error {
314 return k.setStringValue(name, EXPAND_SZ, value)
315 }
316 317 // SetStringsValue sets the data and type of a name value
318 // under key k to value and MULTI_SZ. The value strings
319 // must not contain a zero byte.
320 func (k Key) SetStringsValue(name string, value []string) error {
321 ss := ""
322 for _, s := range value {
323 for i := 0; i < len(s); i++ {
324 if s[i] == 0 {
325 return errors.New("string cannot have 0 inside")
326 }
327 }
328 ss += s + "\x00"
329 }
330 v := utf16.Encode([]rune(ss + "\x00"))
331 buf := (*[1 << 29]byte)(unsafe.Pointer(&v[0]))[: len(v)*2 : len(v)*2]
332 return k.setValue(name, MULTI_SZ, buf)
333 }
334 335 // SetBinaryValue sets the data and type of a name value
336 // under key k to value and BINARY.
337 func (k Key) SetBinaryValue(name string, value []byte) error {
338 return k.setValue(name, BINARY, value)
339 }
340 341 // DeleteValue removes a named value from the key k.
342 func (k Key) DeleteValue(name string) error {
343 namePointer, err := syscall.UTF16PtrFromString(name)
344 if err != nil {
345 return err
346 }
347 return regDeleteValue(syscall.Handle(k), namePointer)
348 }
349 350 // ReadValueNames returns the value names of key k.
351 // The parameter n controls the number of returned names,
352 // analogous to the way os.File.Readdirnames works.
353 func (k Key) ReadValueNames(n int) ([]string, error) {
354 ki, err := k.Stat()
355 if err != nil {
356 return nil, err
357 }
358 names := make([]string, 0, ki.ValueCount)
359 buf := make([]uint16, ki.MaxValueNameLen+1) // extra room for terminating null character
360 loopItems:
361 for i := uint32(0); ; i++ {
362 if n > 0 {
363 if len(names) == n {
364 return names, nil
365 }
366 }
367 l := uint32(len(buf))
368 for {
369 err := regEnumValue(syscall.Handle(k), i, &buf[0], &l, nil, nil, nil, nil)
370 if err == nil {
371 break
372 }
373 if err == syscall.ERROR_MORE_DATA {
374 // Double buffer size and try again.
375 l = uint32(2 * len(buf))
376 buf = make([]uint16, l)
377 continue
378 }
379 if err == _ERROR_NO_MORE_ITEMS {
380 break loopItems
381 }
382 return names, err
383 }
384 names = append(names, syscall.UTF16ToString(buf[:l]))
385 }
386 if n > len(names) {
387 return names, io.EOF
388 }
389 return names, nil
390 }
391