/***************************************************************************
 * _ _ ____ _
 * 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; /* LCOV_EXCL_LINE */

 /* 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) */