chrome/app/delay_load_hook_win.cc

   1 // Copyright (c) 2013 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 "chrome/app/delay_load_hook_win.h"
   6
   7 #if defined(_WIN32_WINNT_WIN8) && _MSC_VER < 1700
   8 // The Windows 8 SDK defines FACILITY_VISUALCPP in winerror.h, and in
   9 // delayimp.h previous to VS2012.
  10 #undef FACILITY_VISUALCPP
  11 #endif
  12 #include <DelayIMP.h>
  13
  14 #include "base/logging.h"
  15 #include "base/strings/string_util.h"
  16 #include "base/strings/stringprintf.h"
  17
  18 // So long as these symbols are supplied to the final binary through an
  19 // object file (as opposed to indirectly through a library), these pointers
  20 // will override the CRT's symbols and direct the notifications to our hook.
  21 // Alternatively referencing the ChromeDelayLoadHook function somehow will
  22 // cause this declaration of these variables to take preference to the delay
  23 // load runtime's defaults (in delayimp.lib).
  24 PfnDliHook __pfnDliNotifyHook2 = ChromeDelayLoadHook;
  25 PfnDliHook __pfnDliFailureHook2 = ChromeDelayLoadHook;
  26
  27
  28 namespace {
  29
  30 FARPROC OnPreLoadLibrary(DelayLoadInfo* info) {
  31   // If the DLL name ends with "-delay.dll", this call is about one of our
  32   // custom import libraries. In this case we need to snip the suffix off,
  33   // and bind to the real DLL.
  34   std::string dll_name(info->szDll);
  35   const char kDelaySuffix[] = "-delay.dll";
  36   if (EndsWith(dll_name, kDelaySuffix, false)) {
  37     // Trim the "-delay.dll" suffix from the string.
  38     dll_name.resize(dll_name.length() - (sizeof(kDelaySuffix) - 1));
  39     dll_name.append(".dll");
  40
  41     return reinterpret_cast<FARPROC>(::LoadLibraryA(dll_name.c_str()));
  42   }
  43
  44   return NULL;
  45 }
  46
  47 }  // namespace
  48
  49 // This function is a delay load notification hook. It is invoked by the
  50 // delay load support in the visual studio runtime.
  51 // See http://msdn.microsoft.com/en-us/library/z9h1h6ty(v=vs.100).aspx for
  52 // details.
  53 extern "C" FARPROC WINAPI ChromeDelayLoadHook(unsigned reason,
  54                                               DelayLoadInfo* info) {
  55   switch (reason) {
  56     case dliNoteStartProcessing:
  57     case dliNoteEndProcessing:
  58       // Nothing to do here.
  59       break;
  60
  61     case dliNotePreLoadLibrary:
  62       return OnPreLoadLibrary(info);
  63       break;
  64
  65     case dliNotePreGetProcAddress:
  66       // Nothing to do here.
  67       break;
  68
  69     case dliFailLoadLib:
  70     case dliFailGetProc:
  71       // Returning NULL from error notifications will cause the delay load
  72       // runtime to raise a VcppException structured exception, that some code
  73       // might want to handle.
  74       return NULL;
  75       break;
  76
  77     default:
  78       NOTREACHED() << "Impossible delay load notification.";
  79       break;
  80   }
  81
  82   // Returning NULL causes the delay load machinery to perform default
  83   // processing for this notification.
  84   return NULL;
  85 }