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/*-
* Copyright (c) 2006,2008 Joseph Koshy
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <assert.h>
#include <libelf.h>
#include <stdint.h>
#include "_libelf.h"
ELFTC_VCSID("$Id: libelf_xlate.c,v 1.2 2020/05/18 06:46:23 jsg Exp $");
/*
* Translate to/from the file representation of ELF objects.
*
* Translation could potentially involve the following
* transformations:
*
* - an endianness conversion,
* - a change of layout, as the file representation of ELF objects
* can differ from their in-memory representation.
* - a change in representation due to a layout version change.
*/
Elf_Data *
_libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding,
int elfclass, int elfmachine, int direction)
{
int byteswap;
size_t cnt, dsz, fsz, msz;
uintptr_t sb, se, db, de;
_libelf_translator_function *xlator;
if (encoding == ELFDATANONE)
encoding = LIBELF_PRIVATE(byteorder);
if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) ||
dst == NULL || src == NULL || dst == src) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY);
if (dst->d_version != src->d_version) {
LIBELF_SET_ERROR(UNIMPL, 0);
return (NULL);
}
if (src->d_buf == NULL || dst->d_buf == NULL) {
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) {
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
(src->d_type, (size_t) 1, src->d_version)) == 0)
return (NULL);
if ((msz = _libelf_msize(src->d_type, elfclass, src->d_version)) == 0)
return (NULL);
if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) {
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
/*
* Determine the number of objects that need to be converted, and
* the space required for the converted objects in the destination
* buffer.
*/
if (direction == ELF_TOMEMORY) {
cnt = (size_t) src->d_size / fsz;
dsz = cnt * msz;
} else {
cnt = (size_t) src->d_size / msz;
dsz = cnt * fsz;
}
if (dst->d_size < dsz) {
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
sb = (uintptr_t) src->d_buf;
se = sb + (size_t) src->d_size;
db = (uintptr_t) dst->d_buf;
de = db + (size_t) dst->d_size;
/*
* Check for overlapping buffers. Note that db == sb is
* allowed.
*/
if (db != sb && de > sb && se > db) {
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
if ((direction == ELF_TOMEMORY ? db : sb) %
_libelf_malign(src->d_type, elfclass)) {
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
dst->d_type = src->d_type;
dst->d_size = dsz;
byteswap = encoding != LIBELF_PRIVATE(byteorder);
if (src->d_size == 0 ||
(db == sb && !byteswap && fsz == msz))
return (dst); /* nothing more to do */
xlator = _libelf_get_translator(src->d_type, direction, elfclass,
elfmachine);
if (!xlator(dst->d_buf, dsz, src->d_buf, cnt, byteswap)) {
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
return (dst);
}
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