reloc.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.
 *
 *----------------------------------------------------------------------
 */

/*
 *	@(#)reloc.c (solib) 
 *
 *	Shared object(SO)support library
 *	Relocation relation
 */

#include "../../so.h"


Inline VOID init_got( DLInfo *dlp );
LOCAL ER relocsection_local( DLInfo *dlp, Elf32_Rel *rel, UW size );
LOCAL ER relocsection_global( DLInfo *dlp );

#define TSD_ING_I_2	2

/*
 * Local portion relocation and symbollink 
 */
LOCAL ER relocsection_local( DLInfo *dlp, Elf32_Rel *rel, UW size )
{
	Elf32_Rel	*end = rel + (size / sizeof(Elf32_Rel));
	W		ldofs = dlp->ldofs;
	VP		*got = dlp->got;
	Elf32_Sym	*symtab = dlp->symtab;
	UW		type, symno;
	UW		*wp;
	ER		err;

	for ( ; rel < end; rel++ ) {
		type = ELF32_R_TYPE(rel->r_info);
		if ( type == R_MIPS_NONE ) {
			continue;
		}

		symno = ELF32_R_SYM(rel->r_info);
		wp = (UW*)((UB *)(rel->r_offset) + ldofs);

		/* Relocation*/
		switch ( type ) {
		  case R_MIPS_REL32:
			if ( symno != 0) {
				if (symno < dlp->mips_gotsym) {
					*wp += (UW)symtab[symno].st_value + (UW)ldofs;
				} else {
					*wp += (UW)got[symno + dlp->mips_local_gotno - dlp->mips_gotsym];
				}
			} else {
				*wp += (UW)ldofs;
			}
			break;

		  default:
			SYSLOG((LOG_ERR,
				"solib: unsupported relocation type (%d)",
				type));
			err = E_REC;
			goto err_ret;
		}
	}

	return E_OK;

err_ret:
	DEBUG_PRINT(("relocsection_local err = %d\n", err));
	return err;
}

/********************************************************************************/
/*
 * "got" global portion relocation and symbol link
 */
LOCAL ER relocsection_global( DLInfo *dlp )
{
	W		ldofs = dlp->ldofs;
	UB		*strtab = dlp->strtab;
	VP		*got = dlp->got + dlp->mips_local_gotno;
	Elf32_Sym	*syment = dlp->symtab + dlp->mips_gotsym;
	Elf32_Sym	*symend = dlp->symtab + dlp->mips_symtabno;
	Elf32_Sym	*sym;

	for ( ; syment < symend; syment++, got++ ) {
		if (syment->st_shndx == SHN_UNDEF) {
			if ((ELF32_ST_TYPE(syment->st_info) == STT_FUNC) && syment->st_value) {
				*got = (VP)((UB *)(syment->st_value) + ldofs);
			} else {
				*got = (VP)__so_resolve( dlp, strtab + syment->st_name, 0, &sym);
			}
		} else if (syment->st_shndx == SHN_COMMON) {
			*got = (VP)__so_resolve( dlp, strtab + syment->st_name, 0, &sym);
		} else if ((ELF32_ST_TYPE(syment->st_info) == STT_FUNC) && (*got != syment->st_value)) {
			*got = (VP)((UB *)(*got) + ldofs);
		} else if (ELF32_ST_TYPE(syment->st_info) == STT_SECTION) {
			if (syment->st_other == 0) {
				*got = (VP)((UB *)(*got) + ldofs);
			}
		} else {
			*got = (VP)__so_resolve( dlp, strtab + syment->st_name, 0, &sym);
		}
	}
	return E_OK;
}

/********************************************************************************/
/*
 * "got" runtime resolver registration and "got" local portion relocation
 */
Inline VOID init_got( DLInfo *dlp )
{
	W	i;
	VP	*got = dlp->got;

	if ( !got ) {
		return;
	}

	/* Register the runtime resolver for sequential link of symbol */
	got[0] = (VP)__so_runtime_resolve;
	got[1] = dlp;

	/* Relocation of "got" local portion  */
	for ( i = TSD_ING_I_2; i < (W)dlp->mips_local_gotno; i++ ) {
		got[i] = (VP)((UB *)(got[i]) + dlp->ldofs);
	}
}

/********************************************************************************/
/*
 * Relocation of the entire load object
 * "lazy" is null. It constantly be "lazy binding"
 */
EXPORT ER __so_relocate( DLInfo *loader, UW lazy )
{
	QUEUE	*q;
	DLInfo	*dlp;
	ER	err;

	/* Relocation of global portion			*/
	/* Relocation is made in order of the latest loading	*/
	q = &__dlInfo.q;
	do {
		dlp = (DLInfo*)(q = q->prev);
		if ( dlp->relocated != 0 ) {
			continue;
		}

		/* Run time resolver registration and "got"local portion relocation */
		init_got(dlp);
		/* Relocation of "got"global portion */
		err = relocsection_global(dlp);
		if ( err < E_OK ) {
			goto err_ret;
		}
		/* Relocation of local portion			*/
		err = relocsection_local(dlp, dlp->reltab, dlp->relsz);
		if ( err < E_OK ) {
			goto err_ret;
		}

		dlp->relocated = TRUE;
	} while ( q != &loader->q );

	return E_OK;

err_ret:
	DEBUG_PRINT(("__so_relocate err = %d\n", err));
	return err;
}