symbol.c

T-kernel 的extension源代码

/*
 *----------------------------------------------------------------------
 *    T-Kernel / Standard Extension
 *
 *    Copyright (C) 2006 by Ken Sakamura. All rights reserved.
 *    T-Kernel / Standard Extension is distributed 
 *      under the T-License for T-Kernel / Standard Extension.
 *----------------------------------------------------------------------
 *
 *    Version:   1.00.00
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2006/8/11.
 *
 *----------------------------------------------------------------------
 */

/*
 *	@(#)symbol.c (libdl) 
 *
 *	DLL support library
 *	Reference to symbol
 */

#include "libdl.h"
#include <tm/tmonitor.h>


/*
 * Search the shared object of the specified address. 
 */
EXPORT DLInfo* __addrdlinfo( VP addr )
{
	QUEUE		*q;
	P_DYNLDINF	*ldinf;

	q = &__dlInfo.q;
	do {
		ldinf = &((DLInfo*)q)->ldinf;
		if (( (UW)addr >= (UW)ldinf->loadaddr )
		  &&( (UW)addr < ((UW)ldinf->loadaddr + ldinf->loadsize)) ) {
			return (DLInfo*)q;
		}
	} while ( (q = q->next) != &__dlInfo.q );

	return NULL;
}

/*
 * Reference to symbol
 *	Search the symbol specified at "symbol" from the shared object specified at "handle",
 *	and return the value to "val".
 *	Return "E_NOEXS" when symbol is not found. In this case, return "NULL" to "val".
 *
 *	The following special "handle" are usable.
 *	DL_DEFAULT	Search the global symbol.
 *	DL_NEXT		Search the local scope. 
 */
EXPORT ER tkse_dlsym( W handle, const char *symbol, UW *val )
{
	VP		retaddr = (VP)__builtin_return_address(0);
	DLInfo		*dlp;
	Elf32_Sym	*sym;
	ER		err;

	err = LockDL();
	if ( err < E_OK ) {
		goto err_ret1;
	}

	switch ( handle ) {
	  case DL_DEFAULT:
		*val = __so_resolve(&__dlInfo, (UB*)symbol, 0, &sym);
		break;

	  case DL_NEXT:
		dlp = __addrdlinfo(retaddr);
		if ( dlp == NULL ) {
			err = E_NOEXS;
			goto err_ret2;
		}
		
		if ( dlp->loader != NULL ) {
			*val = __so_localresolve(dlp->loader, (UB*)symbol, dlp, &sym);
		} else {
			*val = __so_localresolve(dlp, (UB*)symbol, dlp, &sym);
		}
		break;

	  default:
		dlp = __getdlinfo(handle);
		if ( dlp == NULL ) {
			err = E_PAR;
			goto err_ret2;
		}
		*val = __so_localresolve(dlp, (UB*)symbol, 0, &sym);
		break;
	}
	if ( sym == NULL ) {
		err = E_NOEXS;
		goto err_ret2;
	}

	UnlockDL();

	return E_OK;

err_ret2:
	UnlockDL();
err_ret1:
	DEBUG_PRINT(("tkse_dlsym err = %d\n", err));
	return err;
}

/*
 * Reference to symbol (POSIX I/F)
 *
 */
extern int	printf( const char *format, ... );

EXPORT void *dlsym(void *handle, const char *symbol)
{
	ER err;
	UW func;

	if ((handle == RTLD_DEFAULT) || (handle == RTLD_NEXT)) {
		err = tkse_dlsym( (W)handle, symbol, &func );

	} else {
		err = tkse_dlsym( *(W *)handle, symbol, &func );
	}

	if (err >= E_OK) {
		return (void *)func;
	} else {
		return NULL;
	}
}