// Copyright (c) 2013 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 "chrome/app/delay_load_hook_win.h"
#if defined(_WIN32_WINNT_WIN8) && _MSC_VER < 1700
// The Windows 8 SDK defines FACILITY_VISUALCPP in winerror.h, and in
// delayimp.h previous to VS2012.
#undef FACILITY_VISUALCPP
#endif
#include <DelayIMP.h>
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
// So long as these symbols are supplied to the final binary through an
// object file (as opposed to indirectly through a library), these pointers
// will override the CRT's symbols and direct the notifications to our hook.
// Alternatively referencing the ChromeDelayLoadHook function somehow will
// cause this declaration of these variables to take preference to the delay
// load runtime's defaults (in delayimp.lib).
PfnDliHook __pfnDliNotifyHook2 = ChromeDelayLoadHook;
PfnDliHook __pfnDliFailureHook2 = ChromeDelayLoadHook;
namespace {
FARPROC OnPreLoadLibrary(DelayLoadInfo* info) {
// If the DLL name ends with "-delay.dll", this call is about one of our
// custom import libraries. In this case we need to snip the suffix off,
// and bind to the real DLL.
std::string dll_name(info->szDll);
const char kDelaySuffix[] = "-delay.dll";
if (EndsWith(dll_name, kDelaySuffix, false)) {
// Trim the "-delay.dll" suffix from the string.
dll_name.resize(dll_name.length() - (sizeof(kDelaySuffix) - 1));
dll_name.append(".dll");
return reinterpret_cast<FARPROC>(::LoadLibraryA(dll_name.c_str()));
}
return NULL;
}
} // namespace
// This function is a delay load notification hook. It is invoked by the
// delay load support in the visual studio runtime.
// See http://msdn.microsoft.com/en-us/library/z9h1h6ty(v=vs.100).aspx for
// details.
extern "C" FARPROC WINAPI ChromeDelayLoadHook(unsigned reason,
DelayLoadInfo* info) {
switch (reason) {
case dliNoteStartProcessing:
case dliNoteEndProcessing:
// Nothing to do here.
break;
case dliNotePreLoadLibrary:
return OnPreLoadLibrary(info);
break;
case dliNotePreGetProcAddress:
// Nothing to do here.
break;
case dliFailLoadLib:
case dliFailGetProc:
// Returning NULL from error notifications will cause the delay load
// runtime to raise a VcppException structured exception, that some code
// might want to handle.
return NULL;
break;
default:
NOTREACHED() << "Impossible delay load notification.";
break;
}
// Returning NULL causes the delay load machinery to perform default
// processing for this notification.
return NULL;
}