| 1 | /** @file
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| 2 | * IPRT - Lazy share library linking (2nd try).
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| 3 | */
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| 4 |
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| 5 | /*
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| 6 | * Copyright (C) 2013-2020 Oracle Corporation
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| 7 | *
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| 8 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 9 | * available from http://www.virtualbox.org. This file is free software;
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| 10 | * you can redistribute it and/or modify it under the terms of the GNU
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| 11 | * General Public License (GPL) as published by the Free Software
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| 12 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 13 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 14 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 15 | *
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| 16 | * The contents of this file may alternatively be used under the terms
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| 17 | * of the Common Development and Distribution License Version 1.0
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| 18 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 19 | * VirtualBox OSE distribution, in which case the provisions of the
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| 20 | * CDDL are applicable instead of those of the GPL.
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| 21 | *
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| 22 | * You may elect to license modified versions of this file under the
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| 23 | * terms and conditions of either the GPL or the CDDL or both.
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| 24 | */
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| 25 |
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| 26 | #ifndef IPRT_INCLUDED_ldrlazy_h
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| 27 | #define IPRT_INCLUDED_ldrlazy_h
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| 28 | #ifndef RT_WITHOUT_PRAGMA_ONCE
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| 29 | # pragma once
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| 30 | #endif
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| 31 |
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| 32 | #include <iprt/ldr.h>
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| 33 |
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| 34 | /** @defgroup grp_rt_ldrlazy RTLdrLazy - Lazy shared library linking.
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| 35 | * @ingroup grp_rt
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| 36 | *
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| 37 | * This is a set of macros which will produce code for dynamically loading and
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| 38 | * resolving symbols in shared libraries (DLLs).
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| 39 | *
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| 40 | * There is an assembly language alternative to this that only requires writing
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| 41 | * a list of symbols in a format similar to what the microsoft linkers take as
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| 42 | * input when producing DLLs and import libraries. That is probably preferable
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| 43 | * over this code. See src/bldprog/VBoxDef2LazyLoad.cpp.
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| 44 | *
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| 45 | * @{
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| 46 | */
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| 47 |
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| 48 |
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| 49 | /**
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| 50 | * Defines a module for use in lazy resolving.
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| 51 | *
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| 52 | * @param a_Mod The module name (C name).
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| 53 | * @param a_pszFile The file to tell RTLdrLoad to load.
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| 54 | */
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| 55 | #define RTLDRLAZY_MODULE(a_Mod, a_pszFile) \
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| 56 | RTLDRLAZY_MODULE_EX(a_Mod, a_pszFile, RTLdrLoad)
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| 57 |
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| 58 | /**
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| 59 | * Defines a module for use in lazy resolving.
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| 60 | *
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| 61 | * @param a_Mod The module name (C name).
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| 62 | * @param a_pszFile The file to tell RTLdrLoad to load.
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| 63 | * @param a_pfnLoadIt Function to call for loading the DLL, replacing
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| 64 | * RTLdrLoad.
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| 65 | */
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| 66 | #define RTLDRLAZY_MODULE_EX(a_Mod, a_pszFile, a_pfnLoadIt) \
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| 67 | static bool rtLdrLazy_##a_Mod##_Resolve(const char *pszName, void **ppvSymbol) \
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| 68 | { \
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| 69 | static RTLDRMOD volatile s_hMod = NIL_RTLDRMOD; \
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| 70 | static bool volatile s_fLoaded = false; \
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| 71 | RTLDRMOD hMod; \
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| 72 | int rc; \
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| 73 | if (!s_fLoaded) \
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| 74 | { \
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| 75 | rc = a_pfnLoadIt(a_pszFile, &hMod); \
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| 76 | s_hMod = RT_SUCCESS(rc) ? hMod : NIL_RTLDRMOD; \
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| 77 | s_fLoaded = true; \
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| 78 | if (RT_FAILURE(rc)) \
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| 79 | return false; \
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| 80 | } \
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| 81 | hMod = s_hMod; \
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| 82 | if (hMod == NIL_RTLDRMOD) \
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| 83 | return false; \
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| 84 | rc = RTLdrGetSymbol(hMod, pszName, ppvSymbol); \
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| 85 | return RT_SUCCESS(rc); \
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| 86 | }
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| 87 |
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| 88 |
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| 89 |
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| 90 | /** Function name mangler for preventing collision with system prototypes. */
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| 91 | #define RTLDRLAZY_FUNC_NAME(a_Mod, a_Name) a_Mod##__##a_Name
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| 92 |
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| 93 | /**
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| 94 | * Defines a function that should be lazily resolved.
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| 95 | */
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| 96 | #define RTLDRLAZY_FUNC(a_Mod, a_RetType, a_CallConv, a_Name, a_ParamDecl, a_ParamNames, a_ErrRet) \
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| 97 | DECLINLINE(a_RetType) RTLDRLAZY_FUNC_NAME(a_Mod, a_Name) a_ParamDecl \
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| 98 | { \
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| 99 | static a_RetType (a_CallConv * s_pfn) a_ParamDecl; \
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| 100 | if (!s_pfn) \
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| 101 | { \
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| 102 | if (!rtLdrLazy_##a_Mod##_Resolve(#a_Name, (void **)&s_pfn)) \
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| 103 | return a_ErrRet; \
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| 104 | } \
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| 105 | return s_pfn a_ParamNames; \
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| 106 | }
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| 107 |
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| 108 |
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| 109 | /** @} */
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| 110 |
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| 111 | #endif /* !IPRT_INCLUDED_ldrlazy_h */
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| 112 |
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