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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ActCtxResource.h"
#include <string>
#include "mozilla/GetKnownFolderPath.h"
#include "mozilla/WindowsVersion.h"
#include "nsWindowsHelpers.h"
namespace mozilla {
namespace mscom {
#if !defined(HAVE_64BIT_BUILD)
static bool ReadCOMRegDefaultString(const std::wstring& aRegPath,
std::wstring& aOutBuf) {
aOutBuf.clear();
std::wstring fullyQualifiedRegPath;
fullyQualifiedRegPath.append(L"SOFTWARE\\Classes\\");
fullyQualifiedRegPath.append(aRegPath);
// Get the required size and type of the registry value.
// We expect either REG_SZ or REG_EXPAND_SZ.
DWORD type;
DWORD bufLen = 0;
LONG result =
::RegGetValueW(HKEY_LOCAL_MACHINE, fullyQualifiedRegPath.c_str(), nullptr,
RRF_RT_ANY, &type, nullptr, &bufLen);
if (result != ERROR_SUCCESS || (type != REG_SZ && type != REG_EXPAND_SZ)) {
return false;
}
// Now obtain the value
DWORD flags = type == REG_SZ ? RRF_RT_REG_SZ : RRF_RT_REG_EXPAND_SZ;
aOutBuf.resize((bufLen + 1) / sizeof(char16_t));
result = ::RegGetValueW(HKEY_LOCAL_MACHINE, fullyQualifiedRegPath.c_str(),
nullptr, flags, nullptr, &aOutBuf[0], &bufLen);
if (result != ERROR_SUCCESS) {
aOutBuf.clear();
return false;
}
// Truncate terminator
aOutBuf.resize((bufLen + 1) / sizeof(char16_t) - 1);
return true;
}
static bool IsSystemOleAcc(HANDLE aFile) {
if (aFile == INVALID_HANDLE_VALUE) {
return false;
}
BY_HANDLE_FILE_INFORMATION info = {};
if (!::GetFileInformationByHandle(aFile, &info)) {
return false;
}
// Use FOLDERID_SystemX86 so that Windows doesn't give us a redirected
// system32 if we're a 32-bit process running on a 64-bit OS. This is
// necessary because the values that we are reading from the registry
// are not redirected; they reference SysWOW64 directly.
auto systemPath = GetKnownFolderPath(FOLDERID_SystemX86);
if (!systemPath) {
return false;
}
std::wstring oleAccPath(systemPath.get());
oleAccPath.append(L"\\oleacc.dll");
nsAutoHandle oleAcc(
::CreateFileW(oleAccPath.c_str(), GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr));
if (oleAcc.get() == INVALID_HANDLE_VALUE) {
return false;
}
BY_HANDLE_FILE_INFORMATION oleAccInfo = {};
if (!::GetFileInformationByHandle(oleAcc, &oleAccInfo)) {
return false;
}
return info.dwVolumeSerialNumber == oleAccInfo.dwVolumeSerialNumber &&
info.nFileIndexLow == oleAccInfo.nFileIndexLow &&
info.nFileIndexHigh == oleAccInfo.nFileIndexHigh;
}
static bool IsTypelibPreferred() {
// If IAccessible's Proxy/Stub CLSID is kUniversalMarshalerClsid, then any
// external a11y clients are expecting to use a typelib.
const wchar_t kUniversalMarshalerClsid[] =
L"{00020424-0000-0000-C000-000000000046}";
const wchar_t kIAccessiblePSClsidPath[] =
L"Interface\\{618736E0-3C3D-11CF-810C-00AA00389B71}"
L"\\ProxyStubClsid32";
std::wstring psClsid;
if (!ReadCOMRegDefaultString(kIAccessiblePSClsidPath, psClsid)) {
return false;
}
if (psClsid.size() !=
sizeof(kUniversalMarshalerClsid) / sizeof(kUniversalMarshalerClsid)[0] -
1) {
return false;
}
int index = 0;
while (kUniversalMarshalerClsid[index]) {
if (toupper(psClsid[index]) != kUniversalMarshalerClsid[index]) {
return false;
}
index++;
}
return true;
}
static bool IsIAccessibleTypelibRegistered() {
// The system default IAccessible typelib is always registered with version
// 1.1, under the neutral locale (LCID 0).
const wchar_t kIAccessibleTypelibRegPath[] =
L"TypeLib\\{1EA4DBF0-3C3B-11CF-810C-00AA00389B71}\\1.1\\0\\win32";
std::wstring typelibPath;
if (!ReadCOMRegDefaultString(kIAccessibleTypelibRegPath, typelibPath)) {
return false;
}
nsAutoHandle libTestFile(
::CreateFileW(typelibPath.c_str(), GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr));
return IsSystemOleAcc(libTestFile);
}
static bool IsIAccessiblePSRegistered() {
const wchar_t kIAccessiblePSRegPath[] =
L"CLSID\\{03022430-ABC4-11D0-BDE2-00AA001A1953}\\InProcServer32";
std::wstring proxyStubPath;
if (!ReadCOMRegDefaultString(kIAccessiblePSRegPath, proxyStubPath)) {
return false;
}
nsAutoHandle libTestFile(
::CreateFileW(proxyStubPath.c_str(), GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr));
return IsSystemOleAcc(libTestFile);
}
static bool UseIAccessibleProxyStub() {
// If a typelib is preferred then external clients are expecting to use
// typelib marshaling, so we should use that whenever available.
if (IsTypelibPreferred() && IsIAccessibleTypelibRegistered()) {
return false;
}
// Otherwise we try the proxy/stub
if (IsIAccessiblePSRegistered()) {
return true;
}
return false;
}
#endif // !defined(HAVE_64BIT_BUILD)
#if defined(_MSC_VER)
extern "C" IMAGE_DOS_HEADER __ImageBase;
#endif
static HMODULE GetContainingModuleHandle() {
HMODULE thisModule = nullptr;
#if defined(_MSC_VER)
thisModule = reinterpret_cast<HMODULE>(&__ImageBase);
#else
if (!GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
reinterpret_cast<LPCWSTR>(&GetContainingModuleHandle),
&thisModule)) {
return 0;
}
#endif
return thisModule;
}
static uint16_t sActCtxResourceId = 0;
/* static */
void ActCtxResource::SetAccessibilityResourceId(uint16_t aResourceId) {
sActCtxResourceId = aResourceId;
}
/* static */
uint16_t ActCtxResource::GetAccessibilityResourceId() {
return sActCtxResourceId;
}
static void EnsureAccessibilityResourceId() {
if (!sActCtxResourceId) {
#if defined(HAVE_64BIT_BUILD)
// The manifest for 64-bit Windows is embedded with resource ID 64.
sActCtxResourceId = 64;
#else
// The manifest for 32-bit Windows is embedded with resource ID 32.
// Beginning with Windows 10 Creators Update, 32-bit builds always use the
// 64-bit manifest. Older builds of Windows may or may not require the
// 64-bit manifest: UseIAccessibleProxyStub() determines the course of
// action.
if (mozilla::IsWin10CreatorsUpdateOrLater() || UseIAccessibleProxyStub()) {
sActCtxResourceId = 64;
} else {
sActCtxResourceId = 32;
}
#endif // defined(HAVE_64BIT_BUILD)
}
}
ActCtxResource ActCtxResource::GetAccessibilityResource() {
ActCtxResource result = {};
result.mModule = GetContainingModuleHandle();
EnsureAccessibilityResourceId();
result.mId = GetAccessibilityResourceId();
return result;
}
} // namespace mscom
} // namespace mozilla
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