1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "base/win/registry.h"
10 #include "base/logging.h"
11 #include "base/strings/string_util.h"
12 #include "base/threading/thread_restrictions.h"
13 #include "base/win/windows_version.h"
20 // RegEnumValue() reports the number of characters from the name that were
21 // written to the buffer, not how many there are. This constant is the maximum
22 // name size, such that a buffer with this size should read any name.
23 const DWORD MAX_REGISTRY_NAME_SIZE = 16384;
25 // Registry values are read as BYTE* but can have wchar_t* data whose last
26 // wchar_t is truncated. This function converts the reported |byte_size| to
27 // a size in wchar_t that can store a truncated wchar_t if necessary.
28 inline DWORD to_wchar_size(DWORD byte_size) {
29 return (byte_size + sizeof(wchar_t) - 1) / sizeof(wchar_t);
32 // Mask to pull WOW64 access flags out of REGSAM access.
33 const REGSAM kWow64AccessMask = KEY_WOW64_32KEY | KEY_WOW64_64KEY;
37 // Watches for modifications to a key.
38 class RegKey::Watcher : public ObjectWatcher::Delegate {
40 explicit Watcher(RegKey* owner) : owner_(owner) {}
43 bool StartWatching(HKEY key, const ChangeCallback& callback);
45 // Implementation of ObjectWatcher::Delegate.
46 void OnObjectSignaled(HANDLE object) override {
47 DCHECK(watch_event_.IsValid() && watch_event_.Get() == object);
48 ChangeCallback callback = callback_;
55 ScopedHandle watch_event_;
56 ObjectWatcher object_watcher_;
57 ChangeCallback callback_;
58 DISALLOW_COPY_AND_ASSIGN(Watcher);
61 bool RegKey::Watcher::StartWatching(HKEY key, const ChangeCallback& callback) {
63 DCHECK(callback_.is_null());
65 if (!watch_event_.IsValid())
66 watch_event_.Set(CreateEvent(NULL, TRUE, FALSE, NULL));
68 if (!watch_event_.IsValid())
71 DWORD filter = REG_NOTIFY_CHANGE_NAME |
72 REG_NOTIFY_CHANGE_ATTRIBUTES |
73 REG_NOTIFY_CHANGE_LAST_SET |
74 REG_NOTIFY_CHANGE_SECURITY;
76 // Watch the registry key for a change of value.
77 LONG result = RegNotifyChangeKeyValue(key, TRUE, filter, watch_event_.Get(),
79 if (result != ERROR_SUCCESS) {
85 return object_watcher_.StartWatching(watch_event_.Get(), this);
88 // RegKey ----------------------------------------------------------------------
90 RegKey::RegKey() : key_(NULL), wow64access_(0) {
93 RegKey::RegKey(HKEY key) : key_(key), wow64access_(0) {
96 RegKey::RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access)
100 if (access & (KEY_SET_VALUE | KEY_CREATE_SUB_KEY | KEY_CREATE_LINK))
101 Create(rootkey, subkey, access);
103 Open(rootkey, subkey, access);
106 wow64access_ = access & kWow64AccessMask;
114 LONG RegKey::Create(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
115 DWORD disposition_value;
116 return CreateWithDisposition(rootkey, subkey, &disposition_value, access);
119 LONG RegKey::CreateWithDisposition(HKEY rootkey, const wchar_t* subkey,
120 DWORD* disposition, REGSAM access) {
121 DCHECK(rootkey && subkey && access && disposition);
123 LONG result = RegCreateKeyEx(rootkey, subkey, 0, NULL,
124 REG_OPTION_NON_VOLATILE, access, NULL, &subhkey,
126 if (result == ERROR_SUCCESS) {
129 wow64access_ = access & kWow64AccessMask;
135 LONG RegKey::CreateKey(const wchar_t* name, REGSAM access) {
136 DCHECK(name && access);
137 // After the application has accessed an alternate registry view using one of
138 // the [KEY_WOW64_32KEY / KEY_WOW64_64KEY] flags, all subsequent operations
139 // (create, delete, or open) on child registry keys must explicitly use the
140 // same flag. Otherwise, there can be unexpected behavior.
141 // http://msdn.microsoft.com/en-us/library/windows/desktop/aa384129.aspx.
142 if ((access & kWow64AccessMask) != wow64access_) {
144 return ERROR_INVALID_PARAMETER;
147 LONG result = RegCreateKeyEx(key_, name, 0, NULL, REG_OPTION_NON_VOLATILE,
148 access, NULL, &subkey, NULL);
149 if (result == ERROR_SUCCESS) {
152 wow64access_ = access & kWow64AccessMask;
158 LONG RegKey::Open(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
159 DCHECK(rootkey && subkey && access);
162 LONG result = RegOpenKeyEx(rootkey, subkey, 0, access, &subhkey);
163 if (result == ERROR_SUCCESS) {
166 wow64access_ = access & kWow64AccessMask;
172 LONG RegKey::OpenKey(const wchar_t* relative_key_name, REGSAM access) {
173 DCHECK(relative_key_name && access);
174 // After the application has accessed an alternate registry view using one of
175 // the [KEY_WOW64_32KEY / KEY_WOW64_64KEY] flags, all subsequent operations
176 // (create, delete, or open) on child registry keys must explicitly use the
177 // same flag. Otherwise, there can be unexpected behavior.
178 // http://msdn.microsoft.com/en-us/library/windows/desktop/aa384129.aspx.
179 if ((access & kWow64AccessMask) != wow64access_) {
181 return ERROR_INVALID_PARAMETER;
184 LONG result = RegOpenKeyEx(key_, relative_key_name, 0, access, &subkey);
186 // We have to close the current opened key before replacing it with the new
188 if (result == ERROR_SUCCESS) {
191 wow64access_ = access & kWow64AccessMask;
196 void RegKey::Close() {
204 // TODO(wfh): Remove this and other unsafe methods. See http://crbug.com/375400
205 void RegKey::Set(HKEY key) {
212 HKEY RegKey::Take() {
213 DCHECK(wow64access_ == 0);
219 bool RegKey::HasValue(const wchar_t* name) const {
220 return RegQueryValueEx(key_, name, 0, NULL, NULL, NULL) == ERROR_SUCCESS;
223 DWORD RegKey::GetValueCount() const {
225 LONG result = RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
226 NULL, NULL, NULL, NULL);
227 return (result == ERROR_SUCCESS) ? count : 0;
230 LONG RegKey::GetValueNameAt(int index, std::wstring* name) const {
232 DWORD bufsize = arraysize(buf);
233 LONG r = ::RegEnumValue(key_, index, buf, &bufsize, NULL, NULL, NULL, NULL);
234 if (r == ERROR_SUCCESS)
240 LONG RegKey::DeleteKey(const wchar_t* name) {
245 // Verify the key exists before attempting delete to replicate previous
248 RegOpenKeyEx(key_, name, 0, READ_CONTROL | wow64access_, &subkey);
249 if (result != ERROR_SUCCESS)
253 return RegDelRecurse(key_, std::wstring(name), wow64access_);
256 LONG RegKey::DeleteEmptyKey(const wchar_t* name) {
260 HKEY target_key = NULL;
261 LONG result = RegOpenKeyEx(key_, name, 0, KEY_READ | wow64access_,
264 if (result != ERROR_SUCCESS)
268 result = RegQueryInfoKey(target_key, NULL, 0, NULL, NULL, NULL, NULL, &count,
269 NULL, NULL, NULL, NULL);
271 RegCloseKey(target_key);
273 if (result != ERROR_SUCCESS)
277 return RegDeleteKeyExWrapper(key_, name, wow64access_, 0);
279 return ERROR_DIR_NOT_EMPTY;
282 LONG RegKey::DeleteValue(const wchar_t* value_name) {
284 LONG result = RegDeleteValue(key_, value_name);
288 LONG RegKey::ReadValueDW(const wchar_t* name, DWORD* out_value) const {
290 DWORD type = REG_DWORD;
291 DWORD size = sizeof(DWORD);
292 DWORD local_value = 0;
293 LONG result = ReadValue(name, &local_value, &size, &type);
294 if (result == ERROR_SUCCESS) {
295 if ((type == REG_DWORD || type == REG_BINARY) && size == sizeof(DWORD))
296 *out_value = local_value;
298 result = ERROR_CANTREAD;
304 LONG RegKey::ReadInt64(const wchar_t* name, int64* out_value) const {
306 DWORD type = REG_QWORD;
307 int64 local_value = 0;
308 DWORD size = sizeof(local_value);
309 LONG result = ReadValue(name, &local_value, &size, &type);
310 if (result == ERROR_SUCCESS) {
311 if ((type == REG_QWORD || type == REG_BINARY) &&
312 size == sizeof(local_value))
313 *out_value = local_value;
315 result = ERROR_CANTREAD;
321 LONG RegKey::ReadValue(const wchar_t* name, std::wstring* out_value) const {
323 const size_t kMaxStringLength = 1024; // This is after expansion.
324 // Use the one of the other forms of ReadValue if 1024 is too small for you.
325 wchar_t raw_value[kMaxStringLength];
326 DWORD type = REG_SZ, size = sizeof(raw_value);
327 LONG result = ReadValue(name, raw_value, &size, &type);
328 if (result == ERROR_SUCCESS) {
329 if (type == REG_SZ) {
330 *out_value = raw_value;
331 } else if (type == REG_EXPAND_SZ) {
332 wchar_t expanded[kMaxStringLength];
333 size = ExpandEnvironmentStrings(raw_value, expanded, kMaxStringLength);
334 // Success: returns the number of wchar_t's copied
335 // Fail: buffer too small, returns the size required
336 // Fail: other, returns 0
337 if (size == 0 || size > kMaxStringLength) {
338 result = ERROR_MORE_DATA;
340 *out_value = expanded;
343 // Not a string. Oops.
344 result = ERROR_CANTREAD;
351 LONG RegKey::ReadValue(const wchar_t* name,
354 DWORD* dtype) const {
355 LONG result = RegQueryValueEx(key_, name, 0, dtype,
356 reinterpret_cast<LPBYTE>(data), dsize);
360 LONG RegKey::ReadValues(const wchar_t* name,
361 std::vector<std::wstring>* values) {
364 DWORD type = REG_MULTI_SZ;
366 LONG result = ReadValue(name, NULL, &size, &type);
367 if (FAILED(result) || size == 0)
370 if (type != REG_MULTI_SZ)
371 return ERROR_CANTREAD;
373 std::vector<wchar_t> buffer(size / sizeof(wchar_t));
374 result = ReadValue(name, &buffer[0], &size, NULL);
375 if (FAILED(result) || size == 0)
378 // Parse the double-null-terminated list of strings.
379 // Note: This code is paranoid to not read outside of |buf|, in the case where
380 // it may not be properly terminated.
381 const wchar_t* entry = &buffer[0];
382 const wchar_t* buffer_end = entry + (size / sizeof(wchar_t));
383 while (entry < buffer_end && entry[0] != '\0') {
384 const wchar_t* entry_end = std::find(entry, buffer_end, L'\0');
385 values->push_back(std::wstring(entry, entry_end));
386 entry = entry_end + 1;
391 LONG RegKey::WriteValue(const wchar_t* name, DWORD in_value) {
393 name, &in_value, static_cast<DWORD>(sizeof(in_value)), REG_DWORD);
396 LONG RegKey::WriteValue(const wchar_t * name, const wchar_t* in_value) {
397 return WriteValue(name, in_value,
398 static_cast<DWORD>(sizeof(*in_value) * (wcslen(in_value) + 1)), REG_SZ);
401 LONG RegKey::WriteValue(const wchar_t* name,
405 DCHECK(data || !dsize);
407 LONG result = RegSetValueEx(key_, name, 0, dtype,
408 reinterpret_cast<LPBYTE>(const_cast<void*>(data)), dsize);
412 bool RegKey::StartWatching(const ChangeCallback& callback) {
414 key_watcher_.reset(new Watcher(this));
416 if (!key_watcher_.get()->StartWatching(key_, callback))
423 LONG RegKey::RegDeleteKeyExWrapper(HKEY hKey,
424 const wchar_t* lpSubKey,
427 typedef LSTATUS(WINAPI* RegDeleteKeyExPtr)(HKEY, LPCWSTR, REGSAM, DWORD);
429 RegDeleteKeyExPtr reg_delete_key_ex_func =
430 reinterpret_cast<RegDeleteKeyExPtr>(
431 GetProcAddress(GetModuleHandleA("advapi32.dll"), "RegDeleteKeyExW"));
433 if (reg_delete_key_ex_func)
434 return reg_delete_key_ex_func(hKey, lpSubKey, samDesired, Reserved);
436 // Windows XP does not support RegDeleteKeyEx, so fallback to RegDeleteKey.
437 return RegDeleteKey(hKey, lpSubKey);
441 LONG RegKey::RegDelRecurse(HKEY root_key,
442 const std::wstring& name,
444 // First, see if the key can be deleted without having to recurse.
445 LONG result = RegDeleteKeyExWrapper(root_key, name.c_str(), access, 0);
446 if (result == ERROR_SUCCESS)
449 HKEY target_key = NULL;
450 result = RegOpenKeyEx(
451 root_key, name.c_str(), 0, KEY_ENUMERATE_SUB_KEYS | access, &target_key);
453 if (result == ERROR_FILE_NOT_FOUND)
454 return ERROR_SUCCESS;
455 if (result != ERROR_SUCCESS)
458 std::wstring subkey_name(name);
460 // Check for an ending slash and add one if it is missing.
461 if (!name.empty() && subkey_name[name.length() - 1] != L'\\')
462 subkey_name += L"\\";
464 // Enumerate the keys
465 result = ERROR_SUCCESS;
466 const DWORD kMaxKeyNameLength = MAX_PATH;
467 const size_t base_key_length = subkey_name.length();
468 std::wstring key_name;
469 while (result == ERROR_SUCCESS) {
470 DWORD key_size = kMaxKeyNameLength;
471 result = RegEnumKeyEx(target_key,
473 WriteInto(&key_name, kMaxKeyNameLength),
480 if (result != ERROR_SUCCESS)
483 key_name.resize(key_size);
484 subkey_name.resize(base_key_length);
485 subkey_name += key_name;
487 if (RegDelRecurse(root_key, subkey_name, access) != ERROR_SUCCESS)
491 RegCloseKey(target_key);
493 // Try again to delete the key.
494 result = RegDeleteKeyExWrapper(root_key, name.c_str(), access, 0);
499 // RegistryValueIterator ------------------------------------------------------
501 RegistryValueIterator::RegistryValueIterator(HKEY root_key,
502 const wchar_t* folder_key,
504 : name_(MAX_PATH, L'\0'),
505 value_(MAX_PATH, L'\0') {
506 Initialize(root_key, folder_key, wow64access);
509 RegistryValueIterator::RegistryValueIterator(HKEY root_key,
510 const wchar_t* folder_key)
511 : name_(MAX_PATH, L'\0'),
512 value_(MAX_PATH, L'\0') {
513 Initialize(root_key, folder_key, 0);
516 void RegistryValueIterator::Initialize(HKEY root_key,
517 const wchar_t* folder_key,
518 REGSAM wow64access) {
519 DCHECK_EQ(wow64access & ~kWow64AccessMask, static_cast<REGSAM>(0));
521 RegOpenKeyEx(root_key, folder_key, 0, KEY_READ | wow64access, &key_);
522 if (result != ERROR_SUCCESS) {
526 result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
527 NULL, NULL, NULL, NULL);
529 if (result != ERROR_SUCCESS) {
540 RegistryValueIterator::~RegistryValueIterator() {
545 DWORD RegistryValueIterator::ValueCount() const {
547 LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL,
548 &count, NULL, NULL, NULL, NULL);
549 if (result != ERROR_SUCCESS)
555 bool RegistryValueIterator::Valid() const {
556 return key_ != NULL && index_ >= 0;
559 void RegistryValueIterator::operator++() {
564 bool RegistryValueIterator::Read() {
566 DWORD capacity = static_cast<DWORD>(name_.capacity());
567 DWORD name_size = capacity;
568 // |value_size_| is in bytes. Reserve the last character for a NUL.
569 value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
570 LONG result = ::RegEnumValue(
571 key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
572 reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
574 if (result == ERROR_MORE_DATA) {
575 // Registry key names are limited to 255 characters and fit within
576 // MAX_PATH (which is 260) but registry value names can use up to 16,383
577 // characters and the value itself is not limited
578 // (from http://msdn.microsoft.com/en-us/library/windows/desktop/
579 // ms724872(v=vs.85).aspx).
580 // Resize the buffers and retry if their size caused the failure.
581 DWORD value_size_in_wchars = to_wchar_size(value_size_);
582 if (value_size_in_wchars + 1 > value_.size())
583 value_.resize(value_size_in_wchars + 1, L'\0');
584 value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
585 name_size = name_size == capacity ? MAX_REGISTRY_NAME_SIZE : capacity;
586 result = ::RegEnumValue(
587 key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
588 reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
591 if (result == ERROR_SUCCESS) {
592 DCHECK_LT(to_wchar_size(value_size_), value_.size());
593 value_[to_wchar_size(value_size_)] = L'\0';
604 // RegistryKeyIterator --------------------------------------------------------
606 RegistryKeyIterator::RegistryKeyIterator(HKEY root_key,
607 const wchar_t* folder_key) {
608 Initialize(root_key, folder_key, 0);
611 RegistryKeyIterator::RegistryKeyIterator(HKEY root_key,
612 const wchar_t* folder_key,
613 REGSAM wow64access) {
614 Initialize(root_key, folder_key, wow64access);
617 RegistryKeyIterator::~RegistryKeyIterator() {
622 DWORD RegistryKeyIterator::SubkeyCount() const {
624 LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
625 NULL, NULL, NULL, NULL, NULL);
626 if (result != ERROR_SUCCESS)
632 bool RegistryKeyIterator::Valid() const {
633 return key_ != NULL && index_ >= 0;
636 void RegistryKeyIterator::operator++() {
641 bool RegistryKeyIterator::Read() {
643 DWORD ncount = arraysize(name_);
645 LONG r = ::RegEnumKeyEx(key_, index_, name_, &ncount, NULL, NULL,
647 if (ERROR_SUCCESS == r)
655 void RegistryKeyIterator::Initialize(HKEY root_key,
656 const wchar_t* folder_key,
657 REGSAM wow64access) {
658 DCHECK_EQ(wow64access & ~kWow64AccessMask, static_cast<REGSAM>(0));
660 RegOpenKeyEx(root_key, folder_key, 0, KEY_READ | wow64access, &key_);
661 if (result != ERROR_SUCCESS) {
665 LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
666 NULL, NULL, NULL, NULL, NULL);
668 if (result != ERROR_SUCCESS) {