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