runtime-loader.h revision 54c3620994786a33db473956c4e6c3c7d94ab695
/** @file
* IPRT - runtime loader generation
*/
/*
* Copyright (C) 2008 Sun Microsystems, Inc.
*
* 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.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
/* 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:
*
* #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)) \
* ...
*
* where long_param_list is a paramter 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. */
#include <iprt/asm.h>
#include <iprt/assert.h>
#include <iprt/cdefs.h>
#include <iprt/err.h>
#include <iprt/ldr.h>
#include <iprt/log.h>
#include <iprt/thread.h>
#include <iprt/types.h>
#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 *name;
void (**fn)(void);
} SHARED_FUNC;
# define RT_PROXY_STUB(s, dummy1, dummy2, dummy3 ) { #s , & s ## _fn } ,
static SHARED_FUNC SharedFuncs[] =
{
RT_RUNTIME_LOADER_INSERT_SYMBOLS
{ NULL, NULL }
};
# undef RT_PROXY_STUB
enum RT_RTLDR_LOAD_STATE
{
UNLOADED = 0,
LOADING,
DONE
};
static uint32_t rtldrState = UNLOADED;
static uint32_t rtldrRC = VERR_WRONG_ORDER;
/** 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. */
RTR3DECL(int) RT_RUNTIME_LOADER_FUNCTION(void)
{
int rc;
LogFlowFunc(("\n"));
if (ASMAtomicCmpXchgU32(&rtldrState, LOADING, UNLOADED))
{
RTLDRMOD hLib;
rc = RTLdrLoad(RT_RUNTIME_LOADER_LIB_NAME, &hLib);
for (unsigned i = 0; RT_SUCCESS(rc) && SharedFuncs[i].name != NULL; ++i)
rc = RTLdrGetSymbol(hLib, SharedFuncs[i].name, (void**)SharedFuncs[i].fn);
rtldrRC = rc;
rtldrState = DONE;
}
else
{
while(rtldrState == LOADING)
RTThreadYield();
rc = rtldrRC;
}
Assert(rtldrState == DONE);
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