FFmpeg
w32dlfcn.h
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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
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  */
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 */
#define NULL
Definition: coverity.c:32
#define L(x)
Definition: vp56_arith.h:36
#define av_free(p)
void * av_mallocz_array(size_t nmemb, size_t size)
Definition: mem.c:191
const char * name
Definition: opengl_enc.c:102