/** @file * IPRT - Runtime Loader Generation. */ /* * Copyright (C) 2008-2022 Oracle Corporation * * This file is part of VirtualBox Open Source Edition (OSE), as * available from http://www.virtualbox.org. This file is free software; * you can redistribute it and/or modify it under the terms of the GNU * General Public License (GPL) as published by the Free Software * Foundation, in version 2 as it comes in the "COPYING" file of the * VirtualBox OSE distribution. VirtualBox OSE is distributed in the * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. * * The contents of this file may alternatively be used under the terms * of the Common Development and Distribution License Version 1.0 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the * VirtualBox OSE 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. */ #include #ifdef RT_RUNTIME_LOADER_GENERATE_BODY_STUBS # include # include # include #endif /** @defgroup grp_rt_runtime_loader Runtime Loader Generation * @ingroup grp_rt * * How to use this loader generator * * This loader generator can be used to generate stub code for loading a shared * library and its functions at runtime, or for generating a header file with * the declaration of the loader function and optionally declarations for the * functions loaded. It should be included in a header file or a C source * file, after defining certain macros which it makes use of. * * To generate the C source code for function proxy stubs and the library * loader function, you should define the following macros in your source file * before including this header: * * RT_RUNTIME_LOADER_LIB_NAME - the file name of the library to load * RT_RUNTIME_LOADER_FUNCTION - the name of the loader function * RT_RUNTIME_LOADER_INSERT_SYMBOLS - a macro containing the names of the * functions to be loaded, defined in the * following pattern: * @code * #define RT_RUNTIME_LOADER_INSERT_SYMBOLS \ * RT_PROXY_STUB(func_name, ret_type, (long_param_list), (short_param_list)) \ * RT_PROXY_STUB(func_name2, ret_type2, (long_param_list2), (short_param_list2)) \ * ... * @endcode * * where long_param_list is a parameter list for declaring the function of the * form (type1 arg1, type2 arg2, ...) and short_param_list for calling it, of * the form (arg1, arg2, ...). * * To generate the header file, you should define RT_RUNTIME_LOADER_FUNCTION * and if you wish to generate declarations for the functions you should * additionally define RT_RUNTIME_LOADER_INSERT_SYMBOLS as above and * RT_RUNTIME_LOADER_GENERATE_DECLS (without a value) before including this * file. * * @{ */ /** @todo this is far too complicated. A script for generating the files would * probably be preferable. * * bird> An alternative is to generate assembly jump wrappers, this only * requires the symbol names and prefix. I've done this ages ago when we forked * the EMX/GCC toolchain on OS/2... It's a wee bit more annoying in x86 PIC/PIE * mode, but nothing that cannot be dealt with. */ /** @todo r=bird: The use of RTR3DECL here is an unresolved issue. */ /** @todo r=bird: The lack of RT_C_DECLS_BEGIN/END is an unresolved issue. Here * we'll get into trouble if we use the same symbol names as the * original! */ /** @todo r=bird: The prefix usage here is very confused: RT_RUNTIME_LOADER_XXX, * RT_PROXY_STUB, etc. */ #ifdef RT_RUNTIME_LOADER_GENERATE_BODY_STUBS /* The following are the symbols which we need from the library. */ # define RT_PROXY_STUB(function, rettype, signature, shortsig) \ void (*function ## _fn)(void); \ RTR3DECL(rettype) function signature \ { return ( (rettype (*) signature) function ## _fn ) shortsig; } RT_RUNTIME_LOADER_INSERT_SYMBOLS # undef RT_PROXY_STUB /* Now comes a table of functions to be loaded from the library. */ typedef struct { const char *pszName; void (**ppfn)(void); } RTLDRSHAREDFUNC; # define RT_PROXY_STUB(s, dummy1, dummy2, dummy3 ) { #s , & s ## _fn } , static RTLDRSHAREDFUNC g_aSharedFuncs[] = { RT_RUNTIME_LOADER_INSERT_SYMBOLS { NULL, NULL } }; # undef RT_PROXY_STUB /** * The function which does the actual work for RT_RUNTIME_LOADER_FUNCTION, * serialised for thread safety. */ static DECLCALLBACK(int) rtldrLoadOnce(void *) { RTLDRMOD hLib; int rc; LogFlowFunc(("\n")); rc = RTLdrLoadEx(RT_RUNTIME_LOADER_LIB_NAME, &hLib, RTLDRLOAD_FLAGS_LOCAL | RTLDRLOAD_FLAGS_NO_UNLOAD, NULL); for (unsigned i = 0; RT_SUCCESS(rc) && g_aSharedFuncs[i].pszName != NULL; ++i) rc = RTLdrGetSymbol(hLib, g_aSharedFuncs[i].pszName, (void **)g_aSharedFuncs[i].ppfn); LogFlowFunc(("rc = %Rrc\n", rc)); return rc; } /** * Load the shared library RT_RUNTIME_LOADER_LIB_NAME and resolve the symbols * pointed to by RT_RUNTIME_LOADER_INSERT_SYMBOLS. * * May safely be called from multiple threads and will not return until the * library is loaded or has failed to load. * * @returns IPRT status code. */ RTR3DECL(int) RT_RUNTIME_LOADER_FUNCTION(void) { static RTONCE s_Once = RTONCE_INITIALIZER; int rc; LogFlowFunc(("\n")); rc = RTOnce(&s_Once, rtldrLoadOnce, NULL); LogFlowFunc(("rc = %Rrc\n", rc)); return rc; } #elif defined(RT_RUNTIME_LOADER_GENERATE_HEADER) # ifdef RT_RUNTIME_LOADER_GENERATE_DECLS /* Declarations of the functions that we need from * RT_RUNTIME_LOADER_LIB_NAME */ # define RT_PROXY_STUB(function, rettype, signature, shortsig) \ RTR3DECL(rettype) function signature ; RT_RUNTIME_LOADER_INSERT_SYMBOLS # undef RT_PROXY_STUB # endif /* RT_RUNTIME_LOADER_GENERATE_DECLS */ /** * Try to dynamically load the library. This function should be called before * attempting to use any of the library functions. It is safe to call this * function multiple times. * * @returns iprt status code */ RTR3DECL(int) RT_RUNTIME_LOADER_FUNCTION(void); #else # error "One of RT_RUNTIME_LOADER_GENERATE_HEADER or RT_RUNTIME_LOADER_GENERATE_BODY_STUBS must be defined when including this file" #endif /** @} */