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Diffstat (limited to 'include/iprt/ldrlazy.h')
| -rw-r--r-- | include/iprt/ldrlazy.h | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/include/iprt/ldrlazy.h b/include/iprt/ldrlazy.h new file mode 100644 index 00000000..0fa788da --- /dev/null +++ b/include/iprt/ldrlazy.h @@ -0,0 +1,122 @@ +/** @file + * IPRT - Lazy share library linking (2nd try). + */ + +/* + * Copyright (C) 2013-2022 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program 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 + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + +#ifndef IPRT_INCLUDED_ldrlazy_h +#define IPRT_INCLUDED_ldrlazy_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + +#include <iprt/ldr.h> + +/** @defgroup grp_rt_ldrlazy RTLdrLazy - Lazy shared library linking. + * @ingroup grp_rt + * + * This is a set of macros which will produce code for dynamically loading and + * resolving symbols in shared libraries (DLLs). + * + * There is an assembly language alternative to this that only requires writing + * a list of symbols in a format similar to what the microsoft linkers take as + * input when producing DLLs and import libraries. That is probably preferable + * over this code. See src/bldprog/VBoxDef2LazyLoad.cpp. + * + * @{ + */ + + +/** + * Defines a module for use in lazy resolving. + * + * @param a_Mod The module name (C name). + * @param a_pszFile The file to tell RTLdrLoad to load. + */ +#define RTLDRLAZY_MODULE(a_Mod, a_pszFile) \ + RTLDRLAZY_MODULE_EX(a_Mod, a_pszFile, RTLdrLoad) + +/** + * Defines a module for use in lazy resolving. + * + * @param a_Mod The module name (C name). + * @param a_pszFile The file to tell RTLdrLoad to load. + * @param a_pfnLoadIt Function to call for loading the DLL, replacing + * RTLdrLoad. + */ +#define RTLDRLAZY_MODULE_EX(a_Mod, a_pszFile, a_pfnLoadIt) \ + static bool rtLdrLazy_##a_Mod##_Resolve(const char *pszName, void **ppvSymbol) \ + { \ + static RTLDRMOD volatile s_hMod = NIL_RTLDRMOD; \ + static bool volatile s_fLoaded = false; \ + RTLDRMOD hMod; \ + int rc; \ + if (!s_fLoaded) \ + { \ + rc = a_pfnLoadIt(a_pszFile, &hMod); \ + s_hMod = RT_SUCCESS(rc) ? hMod : NIL_RTLDRMOD; \ + s_fLoaded = true; \ + if (RT_FAILURE(rc)) \ + return false; \ + } \ + hMod = s_hMod; \ + if (hMod == NIL_RTLDRMOD) \ + return false; \ + rc = RTLdrGetSymbol(hMod, pszName, ppvSymbol); \ + return RT_SUCCESS(rc); \ + } + + + +/** Function name mangler for preventing collision with system prototypes. */ +#define RTLDRLAZY_FUNC_NAME(a_Mod, a_Name) a_Mod##__##a_Name + +/** + * Defines a function that should be lazily resolved. + */ +#define RTLDRLAZY_FUNC(a_Mod, a_RetType, a_CallConv, a_Name, a_ParamDecl, a_ParamNames, a_ErrRet) \ + DECLINLINE(a_RetType) RTLDRLAZY_FUNC_NAME(a_Mod, a_Name) a_ParamDecl \ + { \ + static a_RetType (a_CallConv * s_pfn) a_ParamDecl; \ + if (!s_pfn) \ + { \ + if (!rtLdrLazy_##a_Mod##_Resolve(#a_Name, (void **)&s_pfn)) \ + return a_ErrRet; \ + } \ + return s_pfn a_ParamNames; \ + } + + +/** @} */ + +#endif /* !IPRT_INCLUDED_ldrlazy_h */ + |