1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg 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 GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #ifndef COMPAT_W32DLFCN_H
20 #define COMPAT_W32DLFCN_H
21
22 #ifdef _WIN32
23 #include <windows.h>
24 #include "config.h"
25 #if (_WIN32_WINNT < 0x0602) || HAVE_WINRT
26 #include "libavutil/wchar_filename.h"
27 #endif
28 /**
29 * Safe function used to open dynamic libs. This attempts to improve program security
30 * by removing the current directory from the dll search path. Only dll's found in the
31 * executable or system directory are allowed to be loaded.
32 * @param name The dynamic lib name.
33 * @return A handle to the opened lib.
34 */
win32_dlopen(const char * name)35 static inline HMODULE win32_dlopen(const char *name)
36 {
37 #if _WIN32_WINNT < 0x0602
38 // Need to check if KB2533623 is available
39 if (!GetProcAddress(GetModuleHandleW(L"kernel32.dll"), "SetDefaultDllDirectories")) {
40 HMODULE module = NULL;
41 wchar_t *path = NULL, *name_w = NULL;
42 DWORD pathlen;
43 if (utf8towchar(name, &name_w))
44 goto exit;
45 path = (wchar_t *)av_mallocz_array(MAX_PATH, sizeof(wchar_t));
46 // Try local directory first
47 pathlen = GetModuleFileNameW(NULL, path, MAX_PATH);
48 pathlen = wcsrchr(path, '\\') - path;
49 if (pathlen == 0 || pathlen + wcslen(name_w) + 2 > MAX_PATH)
50 goto exit;
51 path[pathlen] = '\\';
52 wcscpy(path + pathlen + 1, name_w);
53 module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
54 if (module == NULL) {
55 // Next try System32 directory
56 pathlen = GetSystemDirectoryW(path, MAX_PATH);
57 if (pathlen == 0 || pathlen + wcslen(name_w) + 2 > MAX_PATH)
58 goto exit;
59 path[pathlen] = '\\';
60 wcscpy(path + pathlen + 1, name_w);
61 module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
62 }
63 exit:
64 av_free(path);
65 av_free(name_w);
66 return module;
67 }
68 #endif
69 #ifndef LOAD_LIBRARY_SEARCH_APPLICATION_DIR
70 # define LOAD_LIBRARY_SEARCH_APPLICATION_DIR 0x00000200
71 #endif
72 #ifndef LOAD_LIBRARY_SEARCH_SYSTEM32
73 # define LOAD_LIBRARY_SEARCH_SYSTEM32 0x00000800
74 #endif
75 #if HAVE_WINRT
76 wchar_t *name_w = NULL;
77 int ret;
78 if (utf8towchar(name, &name_w))
79 return NULL;
80 ret = LoadPackagedLibrary(name_w, 0);
81 av_free(name_w);
82 return ret;
83 #else
84 return LoadLibraryExA(name, NULL, LOAD_LIBRARY_SEARCH_APPLICATION_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32);
85 #endif
86 }
87 #define dlopen(name, flags) win32_dlopen(name)
88 #define dlclose FreeLibrary
89 #define dlsym GetProcAddress
90 #else
91 #include <dlfcn.h>
92 #endif
93
94 #endif /* COMPAT_W32DLFCN_H */
95