libelf_xlate.c revision 210338
1251875Speter/*- 2251875Speter * Copyright (c) 2006 Joseph Koshy 3251875Speter * All rights reserved. 4251875Speter * 5251875Speter * Redistribution and use in source and binary forms, with or without 6251875Speter * modification, are permitted provided that the following conditions 7251875Speter * are met: 8251875Speter * 1. Redistributions of source code must retain the above copyright 9251875Speter * notice, this list of conditions and the following disclaimer. 10251875Speter * 2. Redistributions in binary form must reproduce the above copyright 11251875Speter * notice, this list of conditions and the following disclaimer in the 12251875Speter * documentation and/or other materials provided with the distribution. 13251875Speter * 14251875Speter * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15251875Speter * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16251875Speter * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17251875Speter * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18251875Speter * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19251875Speter * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20251875Speter * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21251875Speter * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22251875Speter * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23251875Speter * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24251875Speter * SUCH DAMAGE. 25251875Speter */ 26251875Speter 27251875Speter#include <sys/cdefs.h> 28251875Speter__FBSDID("$FreeBSD: head/lib/libelf/libelf_xlate.c 210338 2010-07-21 10:25:02Z kaiw $"); 29251875Speter 30251875Speter#include <assert.h> 31251875Speter#include <libelf.h> 32251875Speter 33251875Speter#include "_libelf.h" 34251875Speter 35251875Speter/* 36251875Speter * Translate to/from the file representation of ELF objects. 37251875Speter * 38251875Speter * Translation could potentially involve the following 39251875Speter * transformations: 40251875Speter * 41251875Speter * - an endianness conversion, 42251875Speter * - a change of layout, as the file representation of ELF objects 43251875Speter * can differ from their in-memory representation. 44251875Speter * - a change in representation due to a layout version change. 45251875Speter */ 46251875Speter 47251875SpeterElf_Data * 48251875Speter_libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding, 49251875Speter int elfclass, int direction) 50251875Speter{ 51251875Speter int byteswap; 52251875Speter size_t cnt, dsz, fsz, msz; 53251875Speter uintptr_t sb, se, db, de; 54251875Speter 55251875Speter if (encoding == ELFDATANONE) 56251875Speter encoding = LIBELF_PRIVATE(byteorder); 57251875Speter 58251875Speter if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) || 59251875Speter dst == NULL || src == NULL || dst == src) { 60251875Speter LIBELF_SET_ERROR(ARGUMENT, 0); 61251875Speter return (NULL); 62251875Speter } 63251875Speter 64251875Speter assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64); 65251875Speter assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY); 66251875Speter 67251875Speter if (dst->d_version != src->d_version) { 68251875Speter LIBELF_SET_ERROR(UNIMPL, 0); 69251875Speter return (NULL); 70251875Speter } 71251875Speter 72251875Speter if (src->d_buf == NULL || dst->d_buf == NULL) { 73251875Speter LIBELF_SET_ERROR(DATA, 0); 74251875Speter return (NULL); 75251875Speter } 76251875Speter 77251875Speter if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) { 78251875Speter LIBELF_SET_ERROR(DATA, 0); 79251875Speter return (NULL); 80251875Speter } 81251875Speter 82251875Speter if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize) 83251875Speter (src->d_type, (size_t) 1, src->d_version)) == 0) 84251875Speter return (NULL); 85251875Speter 86251875Speter msz = _libelf_msize(src->d_type, elfclass, src->d_version); 87251875Speter 88251875Speter assert(msz > 0); 89251875Speter 90251875Speter if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) { 91251875Speter LIBELF_SET_ERROR(DATA, 0); 92251875Speter return (NULL); 93251875Speter } 94251875Speter 95251875Speter /* 96251875Speter * Determine the number of objects that need to be converted, and 97251875Speter * the space required for the converted objects in the destination 98251875Speter * buffer. 99251875Speter */ 100251875Speter if (direction == ELF_TOMEMORY) { 101251875Speter cnt = src->d_size / fsz; 102251875Speter dsz = cnt * msz; 103251875Speter } else { 104251875Speter cnt = src->d_size / msz; 105251875Speter dsz = cnt * fsz; 106251875Speter } 107251875Speter 108251875Speter if (dst->d_size < dsz) { 109251875Speter LIBELF_SET_ERROR(DATA, 0); 110251875Speter return (NULL); 111251875Speter } 112251875Speter 113251875Speter sb = (uintptr_t) src->d_buf; 114251875Speter se = sb + src->d_size; 115251875Speter db = (uintptr_t) dst->d_buf; 116251875Speter de = db + dst->d_size; 117251875Speter 118251875Speter /* 119251875Speter * Check for overlapping buffers. Note that db == sb is 120251875Speter * allowed. 121251875Speter */ 122251875Speter if (db != sb && de > sb && se > db) { 123251875Speter LIBELF_SET_ERROR(DATA, 0); 124251875Speter return (NULL); 125251875Speter } 126251875Speter 127251875Speter if ((direction == ELF_TOMEMORY ? db : sb) % 128251875Speter _libelf_malign(src->d_type, elfclass)) { 129251875Speter LIBELF_SET_ERROR(DATA, 0); 130251875Speter return (NULL); 131251875Speter } 132251875Speter 133251875Speter dst->d_type = src->d_type; 134251875Speter dst->d_size = dsz; 135251875Speter 136251875Speter byteswap = encoding != LIBELF_PRIVATE(byteorder); 137251875Speter 138251875Speter if (src->d_size == 0 || 139251875Speter (db == sb && !byteswap && fsz == msz)) 140251875Speter return (dst); /* nothing more to do */ 141251875Speter 142251875Speter if (!(_libelf_get_translator(src->d_type, direction, elfclass)) 143251875Speter (dst->d_buf, dsz, src->d_buf, cnt, byteswap)) { 144251875Speter LIBELF_SET_ERROR(DATA, 0); 145251875Speter return (NULL); 146251875Speter } 147251875Speter 148251875Speter return (dst); 149251875Speter} 150251875Speter