151 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			151 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*-
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 * Copyright (c) 2006,2008 Joseph Koshy
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <sys/cdefs.h>
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#include <assert.h>
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#include <libelf.h>
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#include "_libelf.h"
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LIBELF_VCSID("$Id$");
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/*
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 * Translate to/from the file representation of ELF objects.
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 *
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 * Translation could potentially involve the following
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 * transformations:
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 *
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 * - an endianness conversion,
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 * - a change of layout, as the file representation of ELF objects
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 *   can differ from their in-memory representation.
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 * - a change in representation due to a layout version change.
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 */
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Elf_Data *
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_libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding,
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    int elfclass, int direction)
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{
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	int byteswap;
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	size_t cnt, dsz, fsz, msz;
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	uintptr_t sb, se, db, de;
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	if (encoding == ELFDATANONE)
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		encoding = LIBELF_PRIVATE(byteorder);
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	if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) ||
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	    dst == NULL || src == NULL || dst == src)	{
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		LIBELF_SET_ERROR(ARGUMENT, 0);
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		return (NULL);
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	}
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	assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
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	assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY);
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	if (dst->d_version != src->d_version) {
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		LIBELF_SET_ERROR(UNIMPL, 0);
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		return (NULL);
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	}
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	if  (src->d_buf == NULL || dst->d_buf == NULL) {
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		LIBELF_SET_ERROR(DATA, 0);
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		return (NULL);
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	}
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	if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) {
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		LIBELF_SET_ERROR(DATA, 0);
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		return (NULL);
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	}
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	if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
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	    (src->d_type, (size_t) 1, src->d_version)) == 0)
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		return (NULL);
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	msz = _libelf_msize(src->d_type, elfclass, src->d_version);
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	assert(msz > 0);
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	if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) {
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		LIBELF_SET_ERROR(DATA, 0);
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		return (NULL);
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	}
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	/*
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	 * Determine the number of objects that need to be converted, and
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	 * the space required for the converted objects in the destination
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	 * buffer.
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	 */
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	if (direction == ELF_TOMEMORY) {
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		cnt = src->d_size / fsz;
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		dsz = cnt * msz;
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	} else {
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		cnt = src->d_size / msz;
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		dsz = cnt * fsz;
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	}
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	if (dst->d_size  <  dsz) {
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		LIBELF_SET_ERROR(DATA, 0);
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		return (NULL);
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	}
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	sb = (uintptr_t) src->d_buf;
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	se = sb + src->d_size;
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	db = (uintptr_t) dst->d_buf;
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	de = db + dst->d_size;
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	/*
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	 * Check for overlapping buffers.  Note that db == sb is
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	 * allowed.
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	 */
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	if (db != sb && de > sb && se > db) {
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		LIBELF_SET_ERROR(DATA, 0);
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		return (NULL);
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	}
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	if ((direction == ELF_TOMEMORY ? db : sb) %
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	    _libelf_malign(src->d_type, elfclass)) {
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		LIBELF_SET_ERROR(DATA, 0);
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		return (NULL);
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	}
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	dst->d_type = src->d_type;
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	dst->d_size = dsz;
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	byteswap = encoding != LIBELF_PRIVATE(byteorder);
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	if (src->d_size == 0 ||
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	    (db == sb && !byteswap && fsz == msz))
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		return (dst);	/* nothing more to do */
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	if (!(_libelf_get_translator(src->d_type, direction, elfclass))
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	    (dst->d_buf, dsz, src->d_buf, cnt, byteswap)) {
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		LIBELF_SET_ERROR(DATA, 0);
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		return (NULL);
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	}
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	return (dst);
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}
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