cpython/Modules/expat/loadlibrary.c

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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2016 - 2017, Steve Holme, <steve_holme@hotmail.com>.
* Copyright (C) 2017, Expat development team
*
* All rights reserved.
* Licensed under the MIT license:
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
* THIRD PARTY RIGHTS. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH
* THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* Except as contained in this notice, the name of a copyright holder shall
* not be used in advertising or otherwise to promote the sale, use or other
* dealings in this Software without prior written authorization of the
* copyright holder.
*
***************************************************************************/
#if defined(_WIN32)
#include <windows.h>
#include <tchar.h>
HMODULE _Expat_LoadLibrary(LPCTSTR filename);
#if !defined(LOAD_WITH_ALTERED_SEARCH_PATH)
#define LOAD_WITH_ALTERED_SEARCH_PATH 0x00000008
#endif
#if !defined(LOAD_LIBRARY_SEARCH_SYSTEM32)
#define LOAD_LIBRARY_SEARCH_SYSTEM32 0x00000800
#endif
/* We use our own typedef here since some headers might lack these */
typedef HMODULE (APIENTRY *LOADLIBRARYEX_FN)(LPCTSTR, HANDLE, DWORD);
/* See function definitions in winbase.h */
#ifdef UNICODE
# ifdef _WIN32_WCE
# define LOADLIBARYEX L"LoadLibraryExW"
# else
# define LOADLIBARYEX "LoadLibraryExW"
# endif
#else
# define LOADLIBARYEX "LoadLibraryExA"
#endif
/*
* _Expat_LoadLibrary()
*
* This is used to dynamically load DLLs using the most secure method available
* for the version of Windows that we are running on.
*
* Parameters:
*
* filename [in] - The filename or full path of the DLL to load. If only the
* filename is passed then the DLL will be loaded from the
* Windows system directory.
*
* Returns the handle of the module on success; otherwise NULL.
*/
HMODULE _Expat_LoadLibrary(LPCTSTR filename)
{
HMODULE hModule = NULL;
LOADLIBRARYEX_FN pLoadLibraryEx = NULL;
/* Get a handle to kernel32 so we can access it's functions at runtime */
HMODULE hKernel32 = GetModuleHandle(TEXT("kernel32"));
if(!hKernel32)
return NULL;
/* Attempt to find LoadLibraryEx() which is only available on Windows 2000
and above */
pLoadLibraryEx = (LOADLIBRARYEX_FN) GetProcAddress(hKernel32, LOADLIBARYEX);
/* Detect if there's already a path in the filename and load the library if
there is. Note: Both back slashes and forward slashes have been supported
since the earlier days of DOS at an API level although they are not
supported by command prompt */
if(_tcspbrk(filename, TEXT("\\/"))) {
/** !checksrc! disable BANNEDFUNC 1 **/
hModule = pLoadLibraryEx ?
pLoadLibraryEx(filename, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
LoadLibrary(filename);
}
/* Detect if KB2533623 is installed, as LOAD_LIBARY_SEARCH_SYSTEM32 is only
supported on Windows Vista, Windows Server 2008, Windows 7 and Windows
Server 2008 R2 with this patch or natively on Windows 8 and above */
else if(pLoadLibraryEx && GetProcAddress(hKernel32, "AddDllDirectory")) {
/* Load the DLL from the Windows system directory */
hModule = pLoadLibraryEx(filename, NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
}
else {
/* Attempt to get the Windows system path */
UINT systemdirlen = GetSystemDirectory(NULL, 0);
if(systemdirlen) {
/* Allocate space for the full DLL path (Room for the null terminator
is included in systemdirlen) */
size_t filenamelen = _tcslen(filename);
TCHAR *path = malloc(sizeof(TCHAR) * (systemdirlen + 1 + filenamelen));
if(path && GetSystemDirectory(path, systemdirlen)) {
/* Calculate the full DLL path */
_tcscpy(path + _tcslen(path), TEXT("\\"));
_tcscpy(path + _tcslen(path), filename);
/* Load the DLL from the Windows system directory */
/** !checksrc! disable BANNEDFUNC 1 **/
hModule = pLoadLibraryEx ?
pLoadLibraryEx(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH) :
LoadLibrary(path);
}
free(path);
}
}
return hModule;
}
#else /* defined(_WIN32) */
/* ISO C requires a translation unit to contain at least one declaration
[-Wempty-translation-unit] */
typedef int _TRANSLATION_UNIT_LOAD_LIBRARY_C_NOT_EMTPY;
#endif /* defined(_WIN32) */