// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/win/registry.h"
#include <shlwapi.h>
#include <algorithm>
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/threading/thread_restrictions.h"
#pragma comment(lib, "shlwapi.lib") // for SHDeleteKey
namespace base {
namespace win {
namespace {
// RegEnumValue() reports the number of characters from the name that were
// written to the buffer, not how many there are. This constant is the maximum
// name size, such that a buffer with this size should read any name.
const DWORD MAX_REGISTRY_NAME_SIZE = 16384;
// Registry values are read as BYTE* but can have wchar_t* data whose last
// wchar_t is truncated. This function converts the reported |byte_size| to
// a size in wchar_t that can store a truncated wchar_t if necessary.
inline DWORD to_wchar_size(DWORD byte_size) {
return (byte_size + sizeof(wchar_t) - 1) / sizeof(wchar_t);
}
} // namespace
// RegKey ----------------------------------------------------------------------
RegKey::RegKey()
: key_(NULL),
watch_event_(0) {
}
RegKey::RegKey(HKEY key)
: key_(key),
watch_event_(0) {
}
RegKey::RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access)
: key_(NULL),
watch_event_(0) {
if (rootkey) {
if (access & (KEY_SET_VALUE | KEY_CREATE_SUB_KEY | KEY_CREATE_LINK))
Create(rootkey, subkey, access);
else
Open(rootkey, subkey, access);
} else {
DCHECK(!subkey);
}
}
RegKey::~RegKey() {
Close();
}
LONG RegKey::Create(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
DWORD disposition_value;
return CreateWithDisposition(rootkey, subkey, &disposition_value, access);
}
LONG RegKey::CreateWithDisposition(HKEY rootkey, const wchar_t* subkey,
DWORD* disposition, REGSAM access) {
DCHECK(rootkey && subkey && access && disposition);
Close();
LONG result = RegCreateKeyEx(rootkey, subkey, 0, NULL,
REG_OPTION_NON_VOLATILE, access, NULL, &key_,
disposition);
return result;
}
LONG RegKey::CreateKey(const wchar_t* name, REGSAM access) {
DCHECK(name && access);
HKEY subkey = NULL;
LONG result = RegCreateKeyEx(key_, name, 0, NULL, REG_OPTION_NON_VOLATILE,
access, NULL, &subkey, NULL);
Close();
key_ = subkey;
return result;
}
LONG RegKey::Open(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
DCHECK(rootkey && subkey && access);
Close();
LONG result = RegOpenKeyEx(rootkey, subkey, 0, access, &key_);
return result;
}
LONG RegKey::OpenKey(const wchar_t* relative_key_name, REGSAM access) {
DCHECK(relative_key_name && access);
HKEY subkey = NULL;
LONG result = RegOpenKeyEx(key_, relative_key_name, 0, access, &subkey);
// We have to close the current opened key before replacing it with the new
// one.
Close();
key_ = subkey;
return result;
}
void RegKey::Close() {
StopWatching();
if (key_) {
::RegCloseKey(key_);
key_ = NULL;
}
}
void RegKey::Set(HKEY key) {
if (key_ != key) {
Close();
key_ = key;
}
}
HKEY RegKey::Take() {
StopWatching();
HKEY key = key_;
key_ = NULL;
return key;
}
bool RegKey::HasValue(const wchar_t* name) const {
return RegQueryValueEx(key_, name, 0, NULL, NULL, NULL) == ERROR_SUCCESS;
}
DWORD RegKey::GetValueCount() const {
DWORD count = 0;
LONG result = RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
NULL, NULL, NULL, NULL);
return (result == ERROR_SUCCESS) ? count : 0;
}
LONG RegKey::GetValueNameAt(int index, std::wstring* name) const {
wchar_t buf[256];
DWORD bufsize = arraysize(buf);
LONG r = ::RegEnumValue(key_, index, buf, &bufsize, NULL, NULL, NULL, NULL);
if (r == ERROR_SUCCESS)
*name = buf;
return r;
}
LONG RegKey::DeleteKey(const wchar_t* name) {
DCHECK(key_);
DCHECK(name);
LONG result = SHDeleteKey(key_, name);
return result;
}
LONG RegKey::DeleteValue(const wchar_t* value_name) {
DCHECK(key_);
LONG result = RegDeleteValue(key_, value_name);
return result;
}
LONG RegKey::ReadValueDW(const wchar_t* name, DWORD* out_value) const {
DCHECK(out_value);
DWORD type = REG_DWORD;
DWORD size = sizeof(DWORD);
DWORD local_value = 0;
LONG result = ReadValue(name, &local_value, &size, &type);
if (result == ERROR_SUCCESS) {
if ((type == REG_DWORD || type == REG_BINARY) && size == sizeof(DWORD))
*out_value = local_value;
else
result = ERROR_CANTREAD;
}
return result;
}
LONG RegKey::ReadInt64(const wchar_t* name, int64* out_value) const {
DCHECK(out_value);
DWORD type = REG_QWORD;
int64 local_value = 0;
DWORD size = sizeof(local_value);
LONG result = ReadValue(name, &local_value, &size, &type);
if (result == ERROR_SUCCESS) {
if ((type == REG_QWORD || type == REG_BINARY) &&
size == sizeof(local_value))
*out_value = local_value;
else
result = ERROR_CANTREAD;
}
return result;
}
LONG RegKey::ReadValue(const wchar_t* name, std::wstring* out_value) const {
DCHECK(out_value);
const size_t kMaxStringLength = 1024; // This is after expansion.
// Use the one of the other forms of ReadValue if 1024 is too small for you.
wchar_t raw_value[kMaxStringLength];
DWORD type = REG_SZ, size = sizeof(raw_value);
LONG result = ReadValue(name, raw_value, &size, &type);
if (result == ERROR_SUCCESS) {
if (type == REG_SZ) {
*out_value = raw_value;
} else if (type == REG_EXPAND_SZ) {
wchar_t expanded[kMaxStringLength];
size = ExpandEnvironmentStrings(raw_value, expanded, kMaxStringLength);
// Success: returns the number of wchar_t's copied
// Fail: buffer too small, returns the size required
// Fail: other, returns 0
if (size == 0 || size > kMaxStringLength) {
result = ERROR_MORE_DATA;
} else {
*out_value = expanded;
}
} else {
// Not a string. Oops.
result = ERROR_CANTREAD;
}
}
return result;
}
LONG RegKey::ReadValue(const wchar_t* name,
void* data,
DWORD* dsize,
DWORD* dtype) const {
LONG result = RegQueryValueEx(key_, name, 0, dtype,
reinterpret_cast<LPBYTE>(data), dsize);
return result;
}
LONG RegKey::ReadValues(const wchar_t* name,
std::vector<std::wstring>* values) {
values->clear();
DWORD type = REG_MULTI_SZ;
DWORD size = 0;
LONG result = ReadValue(name, NULL, &size, &type);
if (FAILED(result) || size == 0)
return result;
if (type != REG_MULTI_SZ)
return ERROR_CANTREAD;
std::vector<wchar_t> buffer(size / sizeof(wchar_t));
result = ReadValue(name, &buffer[0], &size, NULL);
if (FAILED(result) || size == 0)
return result;
// Parse the double-null-terminated list of strings.
// Note: This code is paranoid to not read outside of |buf|, in the case where
// it may not be properly terminated.
const wchar_t* entry = &buffer[0];
const wchar_t* buffer_end = entry + (size / sizeof(wchar_t));
while (entry < buffer_end && entry[0] != '\0') {
const wchar_t* entry_end = std::find(entry, buffer_end, L'\0');
values->push_back(std::wstring(entry, entry_end));
entry = entry_end + 1;
}
return 0;
}
LONG RegKey::WriteValue(const wchar_t* name, DWORD in_value) {
return WriteValue(
name, &in_value, static_cast<DWORD>(sizeof(in_value)), REG_DWORD);
}
LONG RegKey::WriteValue(const wchar_t * name, const wchar_t* in_value) {
return WriteValue(name, in_value,
static_cast<DWORD>(sizeof(*in_value) * (wcslen(in_value) + 1)), REG_SZ);
}
LONG RegKey::WriteValue(const wchar_t* name,
const void* data,
DWORD dsize,
DWORD dtype) {
DCHECK(data || !dsize);
LONG result = RegSetValueEx(key_, name, 0, dtype,
reinterpret_cast<LPBYTE>(const_cast<void*>(data)), dsize);
return result;
}
LONG RegKey::StartWatching() {
DCHECK(key_);
if (!watch_event_)
watch_event_ = CreateEvent(NULL, TRUE, FALSE, NULL);
DWORD filter = REG_NOTIFY_CHANGE_NAME |
REG_NOTIFY_CHANGE_ATTRIBUTES |
REG_NOTIFY_CHANGE_LAST_SET |
REG_NOTIFY_CHANGE_SECURITY;
// Watch the registry key for a change of value.
LONG result = RegNotifyChangeKeyValue(key_, TRUE, filter, watch_event_, TRUE);
if (result != ERROR_SUCCESS) {
CloseHandle(watch_event_);
watch_event_ = 0;
}
return result;
}
bool RegKey::HasChanged() {
if (watch_event_) {
if (WaitForSingleObject(watch_event_, 0) == WAIT_OBJECT_0) {
StartWatching();
return true;
}
}
return false;
}
LONG RegKey::StopWatching() {
LONG result = ERROR_INVALID_HANDLE;
if (watch_event_) {
CloseHandle(watch_event_);
watch_event_ = 0;
result = ERROR_SUCCESS;
}
return result;
}
// RegistryValueIterator ------------------------------------------------------
RegistryValueIterator::RegistryValueIterator(HKEY root_key,
const wchar_t* folder_key)
: name_(MAX_PATH, L'\0'),
value_(MAX_PATH, L'\0') {
LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
if (result != ERROR_SUCCESS) {
key_ = NULL;
} else {
DWORD count = 0;
result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
NULL, NULL, NULL, NULL);
if (result != ERROR_SUCCESS) {
::RegCloseKey(key_);
key_ = NULL;
} else {
index_ = count - 1;
}
}
Read();
}
RegistryValueIterator::~RegistryValueIterator() {
if (key_)
::RegCloseKey(key_);
}
DWORD RegistryValueIterator::ValueCount() const {
DWORD count = 0;
LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL,
&count, NULL, NULL, NULL, NULL);
if (result != ERROR_SUCCESS)
return 0;
return count;
}
bool RegistryValueIterator::Valid() const {
return key_ != NULL && index_ >= 0;
}
void RegistryValueIterator::operator++() {
--index_;
Read();
}
bool RegistryValueIterator::Read() {
if (Valid()) {
DWORD capacity = static_cast<DWORD>(name_.capacity());
DWORD name_size = capacity;
// |value_size_| is in bytes. Reserve the last character for a NUL.
value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
LONG result = ::RegEnumValue(
key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
if (result == ERROR_MORE_DATA) {
// Registry key names are limited to 255 characters and fit within
// MAX_PATH (which is 260) but registry value names can use up to 16,383
// characters and the value itself is not limited
// (from http://msdn.microsoft.com/en-us/library/windows/desktop/
// ms724872(v=vs.85).aspx).
// Resize the buffers and retry if their size caused the failure.
DWORD value_size_in_wchars = to_wchar_size(value_size_);
if (value_size_in_wchars + 1 > value_.size())
value_.resize(value_size_in_wchars + 1, L'\0');
value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
name_size = name_size == capacity ? MAX_REGISTRY_NAME_SIZE : capacity;
result = ::RegEnumValue(
key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
}
if (result == ERROR_SUCCESS) {
DCHECK_LT(to_wchar_size(value_size_), value_.size());
value_[to_wchar_size(value_size_)] = L'\0';
return true;
}
}
name_[0] = L'\0';
value_[0] = L'\0';
value_size_ = 0;
return false;
}
// RegistryKeyIterator --------------------------------------------------------
RegistryKeyIterator::RegistryKeyIterator(HKEY root_key,
const wchar_t* folder_key) {
LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
if (result != ERROR_SUCCESS) {
key_ = NULL;
} else {
DWORD count = 0;
LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
NULL, NULL, NULL, NULL, NULL);
if (result != ERROR_SUCCESS) {
::RegCloseKey(key_);
key_ = NULL;
} else {
index_ = count - 1;
}
}
Read();
}
RegistryKeyIterator::~RegistryKeyIterator() {
if (key_)
::RegCloseKey(key_);
}
DWORD RegistryKeyIterator::SubkeyCount() const {
DWORD count = 0;
LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
NULL, NULL, NULL, NULL, NULL);
if (result != ERROR_SUCCESS)
return 0;
return count;
}
bool RegistryKeyIterator::Valid() const {
return key_ != NULL && index_ >= 0;
}
void RegistryKeyIterator::operator++() {
--index_;
Read();
}
bool RegistryKeyIterator::Read() {
if (Valid()) {
DWORD ncount = arraysize(name_);
FILETIME written;
LONG r = ::RegEnumKeyEx(key_, index_, name_, &ncount, NULL, NULL,
NULL, &written);
if (ERROR_SUCCESS == r)
return true;
}
name_[0] = '\0';
return false;
}
} // namespace win
} // namespace base