1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 2016 - 2017, Steve Holme, <steve_holme@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 */
_Expat_LoadLibrary(LPCTSTR filename)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