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      1 /***************************************************************************
      2  *                                  _   _ ____  _
      3  *  Project                     ___| | | |  _ \| |
      4  *                             / __| | | | |_) | |
      5  *                            | (__| |_| |  _ <| |___
      6  *                             \___|\___/|_| \_\_____|
      7  *
      8  * Copyright (C) 2016 - 2017, Steve Holme, <steve_holme (at) hotmail.com>.
      9  * Copyright (C) 2017, Expat development team
     10  *
     11  * All rights reserved.
     12  * Licensed under the MIT license:
     13  *
     14  * Permission to  use, copy,  modify, and distribute  this software  for any
     15  * purpose with  or without fee is  hereby granted, provided that  the above
     16  * copyright notice and this permission notice appear in all copies.
     17  *
     18  * THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
     19  * EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
     20  * MERCHANTABILITY, FITNESS FOR A  PARTICULAR PURPOSE AND NONINFRINGEMENT OF
     21  * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
     22  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
     23  * CONTRACT, TORT OR  OTHERWISE, ARISING FROM, OUT OF OR  IN CONNECTION WITH
     24  * THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     25  *
     26  * Except as contained in this notice,  the name of a copyright holder shall
     27  * not be used in advertising or otherwise to promote the sale, use or other
     28  * dealings  in this  Software without  prior written  authorization of  the
     29  * copyright holder.
     30  *
     31  ***************************************************************************/
     32 
     33 #if defined(_WIN32)
     34 
     35 #include <windows.h>
     36 #include <tchar.h>
     37 
     38 
     39 HMODULE _Expat_LoadLibrary(LPCTSTR filename);
     40 
     41 
     42 #if !defined(LOAD_WITH_ALTERED_SEARCH_PATH)
     43 #define LOAD_WITH_ALTERED_SEARCH_PATH  0x00000008
     44 #endif
     45 
     46 #if !defined(LOAD_LIBRARY_SEARCH_SYSTEM32)
     47 #define LOAD_LIBRARY_SEARCH_SYSTEM32   0x00000800
     48 #endif
     49 
     50 /* We use our own typedef here since some headers might lack these */
     51 typedef HMODULE (APIENTRY *LOADLIBRARYEX_FN)(LPCTSTR, HANDLE, DWORD);
     52 
     53 /* See function definitions in winbase.h */
     54 #ifdef UNICODE
     55 #  ifdef _WIN32_WCE
     56 #    define LOADLIBARYEX  L"LoadLibraryExW"
     57 #  else
     58 #    define LOADLIBARYEX  "LoadLibraryExW"
     59 #  endif
     60 #else
     61 #  define LOADLIBARYEX    "LoadLibraryExA"
     62 #endif
     63 
     64 
     65 /*
     66  * _Expat_LoadLibrary()
     67  *
     68  * This is used to dynamically load DLLs using the most secure method available
     69  * for the version of Windows that we are running on.
     70  *
     71  * Parameters:
     72  *
     73  * filename  [in] - The filename or full path of the DLL to load. If only the
     74  *                  filename is passed then the DLL will be loaded from the
     75  *                  Windows system directory.
     76  *
     77  * Returns the handle of the module on success; otherwise NULL.
     78  */
     79 HMODULE _Expat_LoadLibrary(LPCTSTR filename)
     80 {
     81   HMODULE hModule = NULL;
     82   LOADLIBRARYEX_FN pLoadLibraryEx = NULL;
     83 
     84   /* Get a handle to kernel32 so we can access it's functions at runtime */
     85   HMODULE hKernel32 = GetModuleHandle(TEXT("kernel32"));
     86   if(!hKernel32)
     87     return NULL;  /* LCOV_EXCL_LINE */
     88 
     89   /* Attempt to find LoadLibraryEx() which is only available on Windows 2000
     90      and above */
     91   pLoadLibraryEx = (LOADLIBRARYEX_FN) GetProcAddress(hKernel32, LOADLIBARYEX);
     92 
     93   /* Detect if there's already a path in the filename and load the library if
     94      there is. Note: Both back slashes and forward slashes have been supported
     95      since the earlier days of DOS at an API level although they are not
     96      supported by command prompt */
     97   if(_tcspbrk(filename, TEXT("\\/"))) {
     98     /** !checksrc! disable BANNEDFUNC 1 **/
     99     hModule = pLoadLibraryEx ?
    100       pLoadLibraryEx(filename, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
    101       LoadLibrary(filename);
    102   }
    103   /* Detect if KB2533623 is installed, as LOAD_LIBARY_SEARCH_SYSTEM32 is only
    104      supported on Windows Vista, Windows Server 2008, Windows 7 and Windows
    105      Server 2008 R2 with this patch or natively on Windows 8 and above */
    106   else if(pLoadLibraryEx && GetProcAddress(hKernel32, "AddDllDirectory")) {
    107     /* Load the DLL from the Windows system directory */
    108     hModule = pLoadLibraryEx(filename, NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
    109   }
    110   else {
    111     /* Attempt to get the Windows system path */
    112     UINT systemdirlen = GetSystemDirectory(NULL, 0);
    113     if(systemdirlen) {
    114       /* Allocate space for the full DLL path (Room for the null terminator
    115          is included in systemdirlen) */
    116       size_t filenamelen = _tcslen(filename);
    117       TCHAR *path = malloc(sizeof(TCHAR) * (systemdirlen + 1 + filenamelen));
    118       if(path && GetSystemDirectory(path, systemdirlen)) {
    119         /* Calculate the full DLL path */
    120         _tcscpy(path + _tcslen(path), TEXT("\\"));
    121         _tcscpy(path + _tcslen(path), filename);
    122 
    123         /* Load the DLL from the Windows system directory */
    124         /** !checksrc! disable BANNEDFUNC 1 **/
    125         hModule = pLoadLibraryEx ?
    126           pLoadLibraryEx(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
    127           LoadLibrary(path);
    128 
    129       }
    130       free(path);
    131     }
    132   }
    133 
    134   return hModule;
    135 }
    136 
    137 #else /* defined(_WIN32) */
    138 
    139 /* ISO C requires a translation unit to contain at least one declaration
    140    [-Wempty-translation-unit] */
    141 typedef int _TRANSLATION_UNIT_LOAD_LIBRARY_C_NOT_EMTPY;
    142 
    143 #endif /* defined(_WIN32) */
    144