Src/dllpstub.cpp

   1 /* dllpstub.cpp: Help implement DLL proxies
   2  * Copyright (c) 2005 Jochen Tucht
   3  *
   4  * License:     This program is free software; you can redistribute it and/or modify
   5  *                      it under the terms of the GNU General Public License as published by
   6  *                      the Free Software Foundation; either version 2 of the License, or
   7  *                      (at your option) any later version.
   8  *
   9  *                      This program is distributed in the hope that it will be useful,
  10  *                      but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *                      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12  *                      GNU General Public License for more details.
  13  *
  14  *                      You should have received a copy of the GNU General Public License
  15  *                      along with this program; if not, write to the Free Software
  16  *                      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 Please mind 2. a) of the GNU General Public License, and log your changes below.
  19
  20 DATE:           BY:                                     DESCRIPTION:
  21 ==========      ==================      ================================================
  22 2005/02/26      Jochen Tucht            Created
  23 2006/09/10      Kimmo Varis                     Don't use 'export' as variable name
  24                                                                 Visual Studio 2005 warns about it.
  25 */
  26
  27 #include "stdafx.h"
  28 #include "dllpstub.h"
  29 #include <afxdisp.h>
  30 #include <afxinet.h>
  31
  32 /**
  33  * @brief Throw DLLPSTUB related exception.
  34  */
  35 void DLLPSTUB::Throw(LPCSTR name, HMODULE handle, DWORD dwError, bool bFreeLibrary)
  36 {
  37         CString strError = name;
  38         if (handle != nullptr)
  39         {
  40                 TCHAR module[4096];
  41                 module[0] = '@';
  42                 if (::GetModuleFileName(handle, module + 1, 4095) == 0)
  43                 {
  44                         wsprintf(module + 1, _T("%p"), handle);
  45                 }
  46                 strError += strError.IsEmpty() ? module + 1 : module;
  47         }
  48         TCHAR szError[512];
  49         if (CInternetException(dwError).GetErrorMessage(szError + 2, 510))
  50         {
  51                 szError[0] = ':';
  52                 szError[1] = '\n';
  53                 strError += szError;
  54         }
  55         if (bFreeLibrary && handle != nullptr)
  56         {
  57                 FreeLibrary(handle);
  58         }
  59         AfxThrowOleDispatchException(0, strError);
  60 }
  61
  62 /**
  63  * @brief Load a dll and import a number of functions.
  64  */
  65 HMODULE DLLPSTUB::Load()
  66 {
  67         // DLLPSTUB assumes that it is embedded in its owner
  68         // followed by a char array of the DLL name to load
  69         // so it access the char array via *(this + 1)
  70         LPCSTR *proxy = (LPCSTR *) (this + 1);
  71         HMODULE handle = nullptr;
  72         if (LPCSTR name = *proxy)
  73         {
  74                 if (proxy[1] != nullptr && proxy[1] != name)
  75                 {
  76                         handle = LoadLibraryA(name);
  77                         if (handle != nullptr)
  78                         {
  79                                 // If any of the version members are non-zero
  80                                 // then we require that DLL export "DllGetVersion"
  81                                 // and report a version as least as high as our
  82                                 // version number members
  83                                 if (dwMajorVersion || dwMinorVersion || dwBuildNumber)
  84                                 {
  85                                         // Is the DLL up to date?
  86                                         DLLVERSIONINFO dvi{ sizeof dvi };
  87                                         dvi.dwMajorVersion = 0;
  88                                         dvi.dwMinorVersion = 0;
  89                                         dvi.dwBuildNumber = 0;
  90                                         DLLGETVERSIONPROC DllGetVersion = (DLLGETVERSIONPROC)GetProcAddress(handle, "DllGetVersion");
  91                                         if
  92                                         (
  93                                                 DllGetVersion == nullptr
  94                                         ||      FAILED(DllGetVersion(&dvi))
  95                                         ||      (
  96                                                         dwMajorVersion && dvi.dwMajorVersion != dwMajorVersion
  97                                                         ? dvi.dwMajorVersion < dwMajorVersion :
  98                                                         dwMinorVersion && dvi.dwMinorVersion != dwMinorVersion
  99                                                         ? dvi.dwMinorVersion < dwMinorVersion :
 100                                                         dvi.dwBuildNumber < dwBuildNumber
 101                                                 )
 102                                         )
 103                                         {
 104                                                 // Well, that's the most appropriate canned system
 105                                                 // message I came across: If DLL is outdated, it may
 106                                                 // actually lack some interface we need...
 107                                                 Throw(0, handle, CO_S_NOTALLINTERFACES, true);
 108                                         }
 109                                 }
 110                                 LPCSTR *pszExport = proxy;
 111                                 *proxy = nullptr;
 112                                 while ((name = *++pszExport) != nullptr)
 113                                 {
 114                                         *pszExport = (LPCSTR)GetProcAddress(handle, name);
 115                                         if (*pszExport == nullptr)
 116                                         {
 117                                                 *proxy = proxy[1] = name;
 118                                                 pszExport = proxy + 2;
 119                                                 break;
 120                                         }
 121                                 }
 122                                 *pszExport = (LPCSTR)handle;
 123                         }
 124                 }
 125                 if ((name = *proxy) != nullptr)
 126                 {
 127                         DWORD dwError = ERROR_MOD_NOT_FOUND;
 128                         HMODULE handle1 = 0;
 129                         if (proxy[1] == name)
 130                         {
 131                                 dwError = ERROR_PROC_NOT_FOUND;
 132                                 handle1 = (HMODULE)proxy[2];
 133                         }
 134                         Throw(name, handle1, dwError, false);
 135                 }
 136         }
 137         return handle;
 138 }
 139