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/*↩
* This file is part of FFmpeg.↩
*↩
* FFmpeg is free software; you can redistribute it and/or↩
* modify it under the terms of the GNU Lesser General Public↩
* License as published by the Free Software Foundation; either↩
* version 2.1 of the License, or (at your option) any later version.↩
*↩
* FFmpeg is distributed in the hope that it will be useful,↩
* but WITHOUT ANY WARRANTY; without even the implied warranty of↩
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU↩
* Lesser General Public License for more details.↩
*↩
* You should have received a copy of the GNU Lesser General Public↩
* License along with FFmpeg; if not, write to the Free Software↩
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA↩
*/↩
↩
#ifndef COMPAT_W32DLFCN_H↩
#define COMPAT_W32DLFCN_H↩
↩
#ifdef _WIN32↩
#include <stdint.h>↩
↩
#include <windows.h>↩
↩
#include "config.h"↩
#include "libavutil/macros.h"↩
#include "libavutil/wchar_filename.h"↩
↩
static inline wchar_t *get_module_filename(HMODULE module)↩
{↩
wchar_t *path = NULL, *new_path;↩
DWORD path_size = 0, path_len;↩
↩
do {↩
path_size = path_size ? FFMIN(2 * path_size, INT16_MAX + 1) : MAX_PATH;↩
new_path = av_realloc_array(path, path_size, sizeof *path);↩
if (!new_path) {↩
av_free(path);↩
return NULL;↩
}↩
path = new_path;↩
// Returns path_size in case of insufficient buffer.↩
// Whether the error is set or not and whether the output↩
// is null-terminated or not depends on the version of Windows.↩
path_len = GetModuleFileNameW(module, path, path_size);↩
} while (path_len && path_size <= INT16_MAX && path_size <= path_len);↩
↩
if (!path_len) {↩
av_free(path);↩
return NULL;↩
}↩
return path;↩
}↩
↩
/**↩
* Safe function used to open dynamic libs. This attempts to improve program security↩
* by removing the current directory from the dll search path. Only dll's found in the↩
* executable or system directory are allowed to be loaded.↩
* @param name The dynamic lib name.↩
* @return A handle to the opened lib.↩
*/↩
static inline HMODULE win32_dlopen(const char *name)↩
{↩
wchar_t *name_w;↩
HMODULE module = NULL;↩
if (utf8towchar(name, &name_w))↩
name_w = NULL;↩
#if _WIN32_WINNT < 0x0602↩
// On Win7 and earlier we check if KB2533623 is available↩
if (!GetProcAddress(GetModuleHandleW(L"kernel32.dll"), "SetDefaultDllDirectories")) {↩
wchar_t *path = NULL, *new_path;↩
DWORD pathlen, pathsize, namelen;↩
if (!name_w)↩
goto exit;↩
namelen = wcslen(name_w);↩
// Try local directory first↩
path = get_module_filename(NULL);↩
if (!path)↩
goto exit;↩
new_path = wcsrchr(path, '\\');↩
if (!new_path)↩
goto exit;↩
pathlen = new_path - path;↩
pathsize = pathlen + namelen + 2;↩
new_path = av_realloc_array(path, pathsize, sizeof *path);↩
if (!new_path)↩
goto exit;↩
path = new_path;↩
wcscpy(path + pathlen + 1, name_w);↩
module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);↩
if (module == NULL) {↩
// Next try System32 directory↩
pathlen = GetSystemDirectoryW(path, pathsize);↩
if (!pathlen)↩
goto exit;↩
// Buffer is not enough in two cases:↩
// 1. system directory + \ + module name↩
// 2. system directory even without the module name.↩
if (pathlen + namelen + 2 > pathsize) {↩
pathsize = pathlen + namelen + 2;↩
new_path = av_realloc_array(path, pathsize, sizeof *path);↩
if (!new_path)↩
goto exit;↩
path = new_path;↩
// Query again to handle the case #2.↩
pathlen = GetSystemDirectoryW(path, pathsize);↩
if (!pathlen)↩
goto exit;↩
}↩
path[pathlen] = L'\\';↩
wcscpy(path + pathlen + 1, name_w);↩
module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);↩
}↩
exit:↩
av_free(path);↩
av_free(name_w);↩
return module;↩
}↩
#endif↩
#ifndef LOAD_LIBRARY_SEARCH_APPLICATION_DIR↩
# define LOAD_LIBRARY_SEARCH_APPLICATION_DIR 0x00000200↩
#endif↩
#ifndef LOAD_LIBRARY_SEARCH_SYSTEM32↩
# define LOAD_LIBRARY_SEARCH_SYSTEM32 0x00000800↩
#endif↩
#if HAVE_WINRT↩
if (!name_w)↩
return NULL;↩
module = LoadPackagedLibrary(name_w, 0);↩
#else↩
#define LOAD_FLAGS (LOAD_LIBRARY_SEARCH_APPLICATION_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32)↩
/* filename may be be in CP_ACP */↩
if (!name_w)↩
return LoadLibraryExA(name, NULL, LOAD_FLAGS);↩
module = LoadLibraryExW(name_w, NULL, LOAD_FLAGS);↩
#undef LOAD_FLAGS↩
#endif↩
av_free(name_w);↩
return module;↩
}↩
#define dlopen(name, flags) win32_dlopen(name)↩
#define dlclose FreeLibrary↩
#define dlsym GetProcAddress↩
#else↩
#include <dlfcn.h>↩
#endif↩
↩
#endif /* COMPAT_W32DLFCN_H */↩