Source code

Revision control

Copy as Markdown

Other Tools

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 */
#include <windows.h>
// Delayed load libraries are loaded when the first symbol is used.
// The following ensures that we load the delayed loaded libraries from the
// system directory.
struct AutoLoadSystemDependencies {
AutoLoadSystemDependencies() {
// Remove the current directory from the search path for dynamically loaded
// DLLs as a precaution. This call has no effect for delay load DLLs.
HMODULE module = ::GetModuleHandleW(L"kernel32.dll");
if (module) {
// SetDefaultDllDirectories is always available on Windows 8 and above. It
// is also available on Windows Vista, Windows Server 2008, and
// Windows 7 when MS KB2533623 has been applied.
decltype(SetDefaultDllDirectories)* setDefaultDllDirectories =
module, "SetDefaultDllDirectories");
if (setDefaultDllDirectories) {
// When SetDefaultDllDirectories is not available, fallback to preloading
// dlls. The order that these are loaded does not matter since they are
// loaded using the LOAD_WITH_ALTERED_SEARCH_PATH flag.
// DLLs for Firefox x64 on Windows 7 (x64).
// Note: dwmapi.dll is preloaded since a crash will try to load it from the
// application's directory.
static LPCWSTR delayDLLs[] = {
L"apphelp.dll", L"cryptbase.dll", L"cryptsp.dll", L"dwmapi.dll",
L"mpr.dll", L"ntmarta.dll", L"profapi.dll", L"propsys.dll",
L"sspicli.dll", L"wsock32.dll"};
// DLLs for Firefox x86 on Windows XP through Windows 7 (x86 and x64).
// Note: dwmapi.dll is preloaded since a crash will try to load it from the
// application's directory.
static LPCWSTR delayDLLs[] = {
L"apphelp.dll", L"crypt32.dll", L"cryptbase.dll", L"cryptsp.dll",
L"dwmapi.dll", L"mpr.dll", L"msasn1.dll", L"ntmarta.dll",
L"profapi.dll", L"propsys.dll", L"psapi.dll", L"secur32.dll",
L"sspicli.dll", L"userenv.dll", L"uxtheme.dll", L"ws2_32.dll",
L"ws2help.dll", L"wsock32.dll"};
WCHAR systemDirectory[MAX_PATH + 1] = {L'\0'};
// If GetSystemDirectory fails we accept that we'll load the DLLs from the
// normal search path.
GetSystemDirectoryW(systemDirectory, MAX_PATH + 1);
size_t systemDirLen = wcslen(systemDirectory);
// Make the system directory path terminate with a slash
if (systemDirectory[systemDirLen - 1] != L'\\' && systemDirLen) {
systemDirectory[systemDirLen] = L'\\';
// No need to re-null terminate
// For each known DLL ensure it is loaded from the system32 directory
for (size_t i = 0; i < sizeof(delayDLLs) / sizeof(delayDLLs[0]); ++i) {
size_t fileLen = wcslen(delayDLLs[i]);
wcsncpy(systemDirectory + systemDirLen, delayDLLs[i],
MAX_PATH - systemDirLen);
if (systemDirLen + fileLen <= MAX_PATH) {
systemDirectory[systemDirLen + fileLen] = L'\0';
} else {
systemDirectory[MAX_PATH] = L'\0';
LPCWSTR fullModulePath = systemDirectory; // just for code readability
// LOAD_WITH_ALTERED_SEARCH_PATH makes a dll look in its own directory for
// dependencies and is only available on Win 7 and below.
LoadLibraryExW(fullModulePath, nullptr, LOAD_WITH_ALTERED_SEARCH_PATH);
} loadDLLs;