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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 #if _WIN32_WINNT < 0x0602
26 #endif
27 /**
28  * Safe function used to open dynamic libs. This attempts to improve program security
29  * by removing the current directory from the dll search path. Only dll's found in the
30  * executable or system directory are allowed to be loaded.
31  * @param name The dynamic lib name.
32  * @return A handle to the opened lib.
33  */
34 static inline HMODULE win32_dlopen(const char *name)
35 {
36 #if _WIN32_WINNT < 0x0602
37  // Need to check if KB2533623 is available
38  if (!GetProcAddress(GetModuleHandleW(L"kernel32.dll"), "SetDefaultDllDirectories")) {
39  HMODULE module = NULL;
40  wchar_t *path = NULL, *name_w = NULL;
41  DWORD pathlen;
42  if (utf8towchar(name, &name_w))
43  goto exit;
44  path = (wchar_t *)av_mallocz_array(MAX_PATH, sizeof(wchar_t));
45  // Try local directory first
46  pathlen = GetModuleFileNameW(NULL, path, MAX_PATH);
47  pathlen = wcsrchr(path, '\\') - path;
48  if (pathlen == 0 || pathlen + wcslen(name_w) + 2 > MAX_PATH)
49  goto exit;
50  path[pathlen] = '\\';
51  wcscpy(path + pathlen + 1, name_w);
52  module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
53  if (module == NULL) {
54  // Next try System32 directory
55  pathlen = GetSystemDirectoryW(path, MAX_PATH);
56  if (pathlen == 0 || pathlen + wcslen(name_w) + 2 > MAX_PATH)
57  goto exit;
58  path[pathlen] = '\\';
59  wcscpy(path + pathlen + 1, name_w);
60  module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
61  }
62 exit:
63  av_free(path);
64  av_free(name_w);
65  return module;
66  }
67 #endif
68 #ifndef LOAD_LIBRARY_SEARCH_APPLICATION_DIR
69 # define LOAD_LIBRARY_SEARCH_APPLICATION_DIR 0x00000200
70 #endif
71 #ifndef LOAD_LIBRARY_SEARCH_SYSTEM32
72 # define LOAD_LIBRARY_SEARCH_SYSTEM32 0x00000800
73 #endif
74  return LoadLibraryExA(name, NULL, LOAD_LIBRARY_SEARCH_APPLICATION_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32);
75 }
76 #define dlopen(name, flags) win32_dlopen(name)
77 #define dlclose FreeLibrary
78 #define dlsym GetProcAddress
79 #else
80 #include <dlfcn.h>
81 #endif
82 
83 #endif /* COMPAT_W32DLFCN_H */
#define NULL
Definition: coverity.c:32
void * HMODULE
static void * av_mallocz_array(size_t nmemb, size_t size)
Definition: mem.h:229
#define L(x)
Definition: vp56_arith.h:36
uint32_t DWORD
#define av_free(p)
const char * name
Definition: opengl_enc.c:103