base/win/registry.cc

   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.
   4
   5 #include "base/win/registry.h"
   6
   7 #include <shlwapi.h>
   8 #include <algorithm>
   9
  10 #include "base/logging.h"
  11 #include "base/threading/thread_restrictions.h"
  12
  13 #pragma comment(lib, "shlwapi.lib")  // for SHDeleteKey
  14
  15 namespace base {
  16 namespace win {
  17
  18 // RegKey ----------------------------------------------------------------------
  19
  20 RegKey::RegKey()
  21     : key_(NULL),
  22       watch_event_(0) {
  23 }
  24
  25 RegKey::RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access)
  26     : key_(NULL),
  27       watch_event_(0) {
  28   base::ThreadRestrictions::AssertIOAllowed();
  29   if (rootkey) {
  30     if (access & (KEY_SET_VALUE | KEY_CREATE_SUB_KEY | KEY_CREATE_LINK))
  31       Create(rootkey, subkey, access);
  32     else
  33       Open(rootkey, subkey, access);
  34   } else {
  35     DCHECK(!subkey);
  36   }
  37 }
  38
  39 RegKey::~RegKey() {
  40   Close();
  41 }
  42
  43 LONG RegKey::Create(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
  44   DWORD disposition_value;
  45   return CreateWithDisposition(rootkey, subkey, &disposition_value, access);
  46 }
  47
  48 LONG RegKey::CreateWithDisposition(HKEY rootkey, const wchar_t* subkey,
  49                                    DWORD* disposition, REGSAM access) {
  50   base::ThreadRestrictions::AssertIOAllowed();
  51   DCHECK(rootkey && subkey && access && disposition);
  52   Close();
  53
  54   LONG result = RegCreateKeyEx(rootkey, subkey, 0, NULL,
  55                                REG_OPTION_NON_VOLATILE, access, NULL, &key_,
  56                                disposition);
  57   return result;
  58 }
  59
  60 LONG RegKey::CreateKey(const wchar_t* name, REGSAM access) {
  61   base::ThreadRestrictions::AssertIOAllowed();
  62   DCHECK(name && access);
  63
  64   HKEY subkey = NULL;
  65   LONG result = RegCreateKeyEx(key_, name, 0, NULL, REG_OPTION_NON_VOLATILE,
  66                                access, NULL, &subkey, NULL);
  67   Close();
  68
  69   key_ = subkey;
  70   return result;
  71 }
  72
  73 LONG RegKey::Open(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
  74   base::ThreadRestrictions::AssertIOAllowed();
  75   DCHECK(rootkey && subkey && access);
  76   Close();
  77
  78   LONG result = RegOpenKeyEx(rootkey, subkey, 0, access, &key_);
  79   return result;
  80 }
  81
  82 LONG RegKey::OpenKey(const wchar_t* relative_key_name, REGSAM access) {
  83   base::ThreadRestrictions::AssertIOAllowed();
  84   DCHECK(relative_key_name && access);
  85
  86   HKEY subkey = NULL;
  87   LONG result = RegOpenKeyEx(key_, relative_key_name, 0, access, &subkey);
  88
  89   // We have to close the current opened key before replacing it with the new
  90   // one.
  91   Close();
  92
  93   key_ = subkey;
  94   return result;
  95 }
  96
  97 void RegKey::Close() {
  98   base::ThreadRestrictions::AssertIOAllowed();
  99   StopWatching();
 100   if (key_) {
 101     ::RegCloseKey(key_);
 102     key_ = NULL;
 103   }
 104 }
 105
 106 bool RegKey::HasValue(const wchar_t* name) const {
 107   base::ThreadRestrictions::AssertIOAllowed();
 108   return RegQueryValueEx(key_, name, 0, NULL, NULL, NULL) == ERROR_SUCCESS;
 109 }
 110
 111 DWORD RegKey::GetValueCount() const {
 112   base::ThreadRestrictions::AssertIOAllowed();
 113   DWORD count = 0;
 114   LONG result = RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
 115                                 NULL, NULL, NULL, NULL);
 116   return (result == ERROR_SUCCESS) ? count : 0;
 117 }
 118
 119 LONG RegKey::GetValueNameAt(int index, std::wstring* name) const {
 120   base::ThreadRestrictions::AssertIOAllowed();
 121   wchar_t buf[256];
 122   DWORD bufsize = arraysize(buf);
 123   LONG r = ::RegEnumValue(key_, index, buf, &bufsize, NULL, NULL, NULL, NULL);
 124   if (r == ERROR_SUCCESS)
 125     *name = buf;
 126
 127   return r;
 128 }
 129
 130 LONG RegKey::DeleteKey(const wchar_t* name) {
 131   base::ThreadRestrictions::AssertIOAllowed();
 132   DCHECK(key_);
 133   DCHECK(name);
 134   LONG result = SHDeleteKey(key_, name);
 135   return result;
 136 }
 137
 138 LONG RegKey::DeleteValue(const wchar_t* value_name) {
 139   base::ThreadRestrictions::AssertIOAllowed();
 140   DCHECK(key_);
 141   DCHECK(value_name);
 142   LONG result = RegDeleteValue(key_, value_name);
 143   return result;
 144 }
 145
 146 LONG RegKey::ReadValueDW(const wchar_t* name, DWORD* out_value) const {
 147   DCHECK(out_value);
 148   DWORD type = REG_DWORD;
 149   DWORD size = sizeof(DWORD);
 150   DWORD local_value = 0;
 151   LONG result = ReadValue(name, &local_value, &size, &type);
 152   if (result == ERROR_SUCCESS) {
 153     if ((type == REG_DWORD || type == REG_BINARY) && size == sizeof(DWORD))
 154       *out_value = local_value;
 155     else
 156       result = ERROR_CANTREAD;
 157   }
 158
 159   return result;
 160 }
 161
 162 LONG RegKey::ReadInt64(const wchar_t* name, int64* out_value) const {
 163   DCHECK(out_value);
 164   DWORD type = REG_QWORD;
 165   int64 local_value = 0;
 166   DWORD size = sizeof(local_value);
 167   LONG result = ReadValue(name, &local_value, &size, &type);
 168   if (result == ERROR_SUCCESS) {
 169     if ((type == REG_QWORD || type == REG_BINARY) &&
 170         size == sizeof(local_value))
 171       *out_value = local_value;
 172     else
 173       result = ERROR_CANTREAD;
 174   }
 175
 176   return result;
 177 }
 178
 179 LONG RegKey::ReadValue(const wchar_t* name, std::wstring* out_value) const {
 180   base::ThreadRestrictions::AssertIOAllowed();
 181   DCHECK(out_value);
 182   const size_t kMaxStringLength = 1024;  // This is after expansion.
 183   // Use the one of the other forms of ReadValue if 1024 is too small for you.
 184   wchar_t raw_value[kMaxStringLength];
 185   DWORD type = REG_SZ, size = sizeof(raw_value);
 186   LONG result = ReadValue(name, raw_value, &size, &type);
 187   if (result == ERROR_SUCCESS) {
 188     if (type == REG_SZ) {
 189       *out_value = raw_value;
 190     } else if (type == REG_EXPAND_SZ) {
 191       wchar_t expanded[kMaxStringLength];
 192       size = ExpandEnvironmentStrings(raw_value, expanded, kMaxStringLength);
 193       // Success: returns the number of wchar_t's copied
 194       // Fail: buffer too small, returns the size required
 195       // Fail: other, returns 0
 196       if (size == 0 || size > kMaxStringLength) {
 197         result = ERROR_MORE_DATA;
 198       } else {
 199         *out_value = expanded;
 200       }
 201     } else {
 202       // Not a string. Oops.
 203       result = ERROR_CANTREAD;
 204     }
 205   }
 206
 207   return result;
 208 }
 209
 210 LONG RegKey::ReadValue(const wchar_t* name,
 211                        void* data,
 212                        DWORD* dsize,
 213                        DWORD* dtype) const {
 214   base::ThreadRestrictions::AssertIOAllowed();
 215   LONG result = RegQueryValueEx(key_, name, 0, dtype,
 216                                 reinterpret_cast<LPBYTE>(data), dsize);
 217   return result;
 218 }
 219
 220 LONG RegKey::ReadValues(const wchar_t* name,
 221                         std::vector<std::wstring>* values) {
 222   base::ThreadRestrictions::AssertIOAllowed();
 223   values->clear();
 224
 225   DWORD type = REG_MULTI_SZ;
 226   DWORD size = 0;
 227   LONG result = ReadValue(name, NULL, &size, &type);
 228   if (FAILED(result) || size == 0)
 229     return result;
 230
 231   if (type != REG_MULTI_SZ)
 232     return ERROR_CANTREAD;
 233
 234   std::vector<wchar_t> buffer(size / sizeof(wchar_t));
 235   result = ReadValue(name, &buffer[0], &size, NULL);
 236   if (FAILED(result) || size == 0)
 237     return result;
 238
 239   // Parse the double-null-terminated list of strings.
 240   // Note: This code is paranoid to not read outside of |buf|, in the case where
 241   // it may not be properly terminated.
 242   const wchar_t* entry = &buffer[0];
 243   const wchar_t* buffer_end = entry + (size / sizeof(wchar_t));
 244   while (entry < buffer_end && entry[0] != '\0') {
 245     const wchar_t* entry_end = std::find(entry, buffer_end, L'\0');
 246     values->push_back(std::wstring(entry, entry_end));
 247     entry = entry_end + 1;
 248   }
 249   return 0;
 250 }
 251
 252 LONG RegKey::WriteValue(const wchar_t* name, DWORD in_value) {
 253   return WriteValue(
 254       name, &in_value, static_cast<DWORD>(sizeof(in_value)), REG_DWORD);
 255 }
 256
 257 LONG RegKey::WriteValue(const wchar_t * name, const wchar_t* in_value) {
 258   return WriteValue(name, in_value,
 259       static_cast<DWORD>(sizeof(*in_value) * (wcslen(in_value) + 1)), REG_SZ);
 260 }
 261
 262 LONG RegKey::WriteValue(const wchar_t* name,
 263                         const void* data,
 264                         DWORD dsize,
 265                         DWORD dtype) {
 266   base::ThreadRestrictions::AssertIOAllowed();
 267   DCHECK(data || !dsize);
 268
 269   LONG result = RegSetValueEx(key_, name, 0, dtype,
 270       reinterpret_cast<LPBYTE>(const_cast<void*>(data)), dsize);
 271   return result;
 272 }
 273
 274 LONG RegKey::StartWatching() {
 275   DCHECK(key_);
 276   if (!watch_event_)
 277     watch_event_ = CreateEvent(NULL, TRUE, FALSE, NULL);
 278
 279   DWORD filter = REG_NOTIFY_CHANGE_NAME |
 280                  REG_NOTIFY_CHANGE_ATTRIBUTES |
 281                  REG_NOTIFY_CHANGE_LAST_SET |
 282                  REG_NOTIFY_CHANGE_SECURITY;
 283
 284   // Watch the registry key for a change of value.
 285   LONG result = RegNotifyChangeKeyValue(key_, TRUE, filter, watch_event_, TRUE);
 286   if (result != ERROR_SUCCESS) {
 287     CloseHandle(watch_event_);
 288     watch_event_ = 0;
 289   }
 290
 291   return result;
 292 }
 293
 294 bool RegKey::HasChanged() {
 295   if (watch_event_) {
 296     if (WaitForSingleObject(watch_event_, 0) == WAIT_OBJECT_0) {
 297       StartWatching();
 298       return true;
 299     }
 300   }
 301   return false;
 302 }
 303
 304 LONG RegKey::StopWatching() {
 305   LONG result = ERROR_INVALID_HANDLE;
 306   if (watch_event_) {
 307     CloseHandle(watch_event_);
 308     watch_event_ = 0;
 309     result = ERROR_SUCCESS;
 310   }
 311   return result;
 312 }
 313
 314 // RegistryValueIterator ------------------------------------------------------
 315
 316 RegistryValueIterator::RegistryValueIterator(HKEY root_key,
 317                                              const wchar_t* folder_key) {
 318   base::ThreadRestrictions::AssertIOAllowed();
 319
 320   LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
 321   if (result != ERROR_SUCCESS) {
 322     key_ = NULL;
 323   } else {
 324     DWORD count = 0;
 325     result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
 326                                NULL, NULL, NULL, NULL);
 327
 328     if (result != ERROR_SUCCESS) {
 329       ::RegCloseKey(key_);
 330       key_ = NULL;
 331     } else {
 332       index_ = count - 1;
 333     }
 334   }
 335
 336   Read();
 337 }
 338
 339 RegistryValueIterator::~RegistryValueIterator() {
 340   base::ThreadRestrictions::AssertIOAllowed();
 341   if (key_)
 342     ::RegCloseKey(key_);
 343 }
 344
 345 DWORD RegistryValueIterator::ValueCount() const {
 346   base::ThreadRestrictions::AssertIOAllowed();
 347   DWORD count = 0;
 348   LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL,
 349                                   &count, NULL, NULL, NULL, NULL);
 350   if (result != ERROR_SUCCESS)
 351     return 0;
 352
 353   return count;
 354 }
 355
 356 bool RegistryValueIterator::Valid() const {
 357   return key_ != NULL && index_ >= 0;
 358 }
 359
 360 void RegistryValueIterator::operator++() {
 361   --index_;
 362   Read();
 363 }
 364
 365 bool RegistryValueIterator::Read() {
 366   base::ThreadRestrictions::AssertIOAllowed();
 367   if (Valid()) {
 368     DWORD ncount = arraysize(name_);
 369     value_size_ = sizeof(value_);
 370     LONG r = ::RegEnumValue(key_, index_, name_, &ncount, NULL, &type_,
 371                             reinterpret_cast<BYTE*>(value_), &value_size_);
 372     if (ERROR_SUCCESS == r)
 373       return true;
 374   }
 375
 376   name_[0] = '\0';
 377   value_[0] = '\0';
 378   value_size_ = 0;
 379   return false;
 380 }
 381
 382 // RegistryKeyIterator --------------------------------------------------------
 383
 384 RegistryKeyIterator::RegistryKeyIterator(HKEY root_key,
 385                                          const wchar_t* folder_key) {
 386   base::ThreadRestrictions::AssertIOAllowed();
 387   LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
 388   if (result != ERROR_SUCCESS) {
 389     key_ = NULL;
 390   } else {
 391     DWORD count = 0;
 392     LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
 393                                     NULL, NULL, NULL, NULL, NULL);
 394
 395     if (result != ERROR_SUCCESS) {
 396       ::RegCloseKey(key_);
 397       key_ = NULL;
 398     } else {
 399       index_ = count - 1;
 400     }
 401   }
 402
 403   Read();
 404 }
 405
 406 RegistryKeyIterator::~RegistryKeyIterator() {
 407   base::ThreadRestrictions::AssertIOAllowed();
 408   if (key_)
 409     ::RegCloseKey(key_);
 410 }
 411
 412 DWORD RegistryKeyIterator::SubkeyCount() const {
 413   base::ThreadRestrictions::AssertIOAllowed();
 414   DWORD count = 0;
 415   LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
 416                                   NULL, NULL, NULL, NULL, NULL);
 417   if (result != ERROR_SUCCESS)
 418     return 0;
 419
 420   return count;
 421 }
 422
 423 bool RegistryKeyIterator::Valid() const {
 424   return key_ != NULL && index_ >= 0;
 425 }
 426
 427 void RegistryKeyIterator::operator++() {
 428   --index_;
 429   Read();
 430 }
 431
 432 bool RegistryKeyIterator::Read() {
 433   base::ThreadRestrictions::AssertIOAllowed();
 434   if (Valid()) {
 435     DWORD ncount = arraysize(name_);
 436     FILETIME written;
 437     LONG r = ::RegEnumKeyEx(key_, index_, name_, &ncount, NULL, NULL,
 438                             NULL, &written);
 439     if (ERROR_SUCCESS == r)
 440       return true;
 441   }
 442
 443   name_[0] = '\0';
 444   return false;
 445 }
 446
 447 }  // namespace win
 448 }  // namespace base