1 /* $NetBSD: libelf_xlate.c,v 1.2 2014/03/09 16:58:04 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2006,2008 Joseph Koshy 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #if HAVE_NBTOOL_CONFIG_H 30 # include "nbtool_config.h" 31 #endif 32 33 #include <sys/cdefs.h> 34 35 #include <assert.h> 36 #include <libelf.h> 37 38 #include "_libelf.h" 39 40 __RCSID("$NetBSD: libelf_xlate.c,v 1.2 2014/03/09 16:58:04 christos Exp $"); 41 ELFTC_VCSID("Id: libelf_xlate.c 2225 2011-11-26 18:55:54Z jkoshy "); 42 43 /* 44 * Translate to/from the file representation of ELF objects. 45 * 46 * Translation could potentially involve the following 47 * transformations: 48 * 49 * - an endianness conversion, 50 * - a change of layout, as the file representation of ELF objects 51 * can differ from their in-memory representation. 52 * - a change in representation due to a layout version change. 53 */ 54 55 Elf_Data * 56 _libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding, 57 int elfclass, int direction) 58 { 59 int byteswap; 60 size_t cnt, dsz, fsz, msz; 61 uintptr_t sb, se, db, de; 62 63 if (encoding == ELFDATANONE) 64 encoding = _libelf_host_byteorder(); 65 66 if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) || 67 dst == NULL || src == NULL || dst == src) { 68 LIBELF_SET_ERROR(ARGUMENT, 0); 69 return (NULL); 70 } 71 72 assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64); 73 assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY); 74 75 if (dst->d_version != src->d_version) { 76 LIBELF_SET_ERROR(UNIMPL, 0); 77 return (NULL); 78 } 79 80 if (src->d_buf == NULL || dst->d_buf == NULL) { 81 LIBELF_SET_ERROR(DATA, 0); 82 return (NULL); 83 } 84 85 if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) { 86 LIBELF_SET_ERROR(DATA, 0); 87 return (NULL); 88 } 89 90 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize) 91 (src->d_type, (size_t) 1, src->d_version)) == 0) 92 return (NULL); 93 94 msz = _libelf_msize(src->d_type, elfclass, src->d_version); 95 96 assert(msz > 0); 97 98 if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) { 99 LIBELF_SET_ERROR(DATA, 0); 100 return (NULL); 101 } 102 103 /* 104 * Determine the number of objects that need to be converted, and 105 * the space required for the converted objects in the destination 106 * buffer. 107 */ 108 if (direction == ELF_TOMEMORY) { 109 cnt = src->d_size / fsz; 110 dsz = cnt * msz; 111 } else { 112 cnt = src->d_size / msz; 113 dsz = cnt * fsz; 114 } 115 116 if (dst->d_size < dsz) { 117 LIBELF_SET_ERROR(DATA, 0); 118 return (NULL); 119 } 120 121 sb = (uintptr_t) src->d_buf; 122 se = sb + src->d_size; 123 db = (uintptr_t) dst->d_buf; 124 de = db + dst->d_size; 125 126 /* 127 * Check for overlapping buffers. Note that db == sb is 128 * allowed. 129 */ 130 if (db != sb && de > sb && se > db) { 131 LIBELF_SET_ERROR(DATA, 0); 132 return (NULL); 133 } 134 135 if ((direction == ELF_TOMEMORY ? db : sb) % 136 _libelf_malign(src->d_type, elfclass)) { 137 LIBELF_SET_ERROR(DATA, 0); 138 return (NULL); 139 } 140 141 dst->d_type = src->d_type; 142 dst->d_size = dsz; 143 144 byteswap = encoding != _libelf_host_byteorder(); 145 146 if (src->d_size == 0 || 147 (db == sb && !byteswap && fsz == msz)) 148 return (dst); /* nothing more to do */ 149 150 if (!(_libelf_get_translator(src->d_type, direction, elfclass)) 151 (dst->d_buf, dsz, src->d_buf, cnt, byteswap)) { 152 LIBELF_SET_ERROR(DATA, 0); 153 return (NULL); 154 } 155 156 return (dst); 157 } 158