Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 179 insertions, 0 deletions

diff --git a/include/iprt/runtime-loader.h b/include/iprt/runtime-loader.h
new file mode 100644
index 00000000..a1546851
--- /dev/null
+++ b/include/iprt/runtime-loader.h
@@ -0,0 +1,179 @@
+/** @file
+ * IPRT - Runtime Loader Generation.
+ */
+
+/*
+ * Copyright (C) 2008-2019 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 <iprt/types.h>
+#ifdef RT_RUNTIME_LOADER_GENERATE_BODY_STUBS
+# include <iprt/ldr.h>
+# include <iprt/log.h>
+# include <iprt/once.h>
+#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 = RTLdrLoad(RT_RUNTIME_LOADER_LIB_NAME, &hLib);
+    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
+
+/** @} */
+