elf_data.c revision 210338
1/*- 2 * Copyright (c) 2006 Joseph Koshy 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/lib/libelf/elf_data.c 210338 2010-07-21 10:25:02Z kaiw $"); 29 30#include <assert.h> 31#include <errno.h> 32#include <libelf.h> 33#include <stdlib.h> 34 35#include "_libelf.h" 36 37 38Elf_Data * 39elf_getdata(Elf_Scn *s, Elf_Data *d) 40{ 41 Elf *e; 42 size_t fsz, msz, count; 43 int elfclass, elftype; 44 unsigned int sh_type; 45 uint64_t sh_align, sh_offset, sh_size; 46 int (*xlate)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap); 47 48 if (s == NULL || (e = s->s_elf) == NULL || e->e_kind != ELF_K_ELF || 49 (d != NULL && s != d->d_scn)) { 50 LIBELF_SET_ERROR(ARGUMENT, 0); 51 return (NULL); 52 } 53 54 if (d == NULL && (d = STAILQ_FIRST(&s->s_data)) != NULL) 55 return (d); 56 57 if (d != NULL) 58 return (STAILQ_NEXT(d, d_next)); 59 60 if (e->e_rawfile == NULL) { 61 LIBELF_SET_ERROR(SEQUENCE, 0); 62 return (NULL); 63 } 64 65 elfclass = e->e_class; 66 67 assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64); 68 69 if (elfclass == ELFCLASS32) { 70 sh_type = s->s_shdr.s_shdr32.sh_type; 71 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset; 72 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size; 73 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign; 74 } else { 75 sh_type = s->s_shdr.s_shdr64.sh_type; 76 sh_offset = s->s_shdr.s_shdr64.sh_offset; 77 sh_size = s->s_shdr.s_shdr64.sh_size; 78 sh_align = s->s_shdr.s_shdr64.sh_addralign; 79 } 80 81 if (sh_type == SHT_NULL) 82 return (NULL); 83 84 if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST || 85 elftype > ELF_T_LAST || (sh_type != SHT_NOBITS && 86 sh_offset + sh_size > (uint64_t) e->e_rawsize)) { 87 LIBELF_SET_ERROR(SECTION, 0); 88 return (NULL); 89 } 90 91 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize) 92 (elftype, (size_t) 1, e->e_version)) == 0) { 93 LIBELF_SET_ERROR(UNIMPL, 0); 94 return (NULL); 95 } 96 97 if (sh_size % fsz) { 98 LIBELF_SET_ERROR(SECTION, 0); 99 return (NULL); 100 } 101 102 count = sh_size / fsz; 103 104 msz = _libelf_msize(elftype, elfclass, e->e_version); 105 106 assert(msz > 0); 107 108 if ((d = _libelf_allocate_data(s)) == NULL) 109 return (NULL); 110 111 d->d_buf = NULL; 112 d->d_off = 0; 113 d->d_align = sh_align; 114 d->d_size = msz * count; 115 d->d_type = elftype; 116 d->d_version = e->e_version; 117 118 if (sh_type == SHT_NOBITS) 119 return (d); 120 121 if ((d->d_buf = malloc(msz*count)) == NULL) { 122 (void) _libelf_release_data(d); 123 LIBELF_SET_ERROR(RESOURCE, 0); 124 return (NULL); 125 } 126 127 d->d_flags |= LIBELF_F_MALLOCED; 128 129 xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass); 130 if (!(*xlate)(d->d_buf, d->d_size, e->e_rawfile + sh_offset, count, 131 e->e_byteorder != LIBELF_PRIVATE(byteorder))) { 132 _libelf_release_data(d); 133 LIBELF_SET_ERROR(DATA, 0); 134 return (NULL); 135 } 136 137 STAILQ_INSERT_TAIL(&s->s_data, d, d_next); 138 139 return (d); 140} 141 142Elf_Data * 143elf_newdata(Elf_Scn *s) 144{ 145 Elf *e; 146 Elf_Data *d; 147 148 if (s == NULL || (e = s->s_elf) == NULL || 149 e->e_kind != ELF_K_ELF) { 150 LIBELF_SET_ERROR(ARGUMENT, 0); 151 return (NULL); 152 } 153 154 /* 155 * elf_newdata() has to append a data descriptor, so 156 * bring in existing section data if not already present. 157 */ 158 if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data)) 159 if (elf_getdata(s, NULL) == NULL) 160 return (NULL); 161 162 if ((d = _libelf_allocate_data(s)) == NULL) 163 return (NULL); 164 165 STAILQ_INSERT_TAIL(&s->s_data, d, d_next); 166 167 d->d_align = 1; 168 d->d_buf = NULL; 169 d->d_off = (uint64_t) ~0; 170 d->d_size = 0; 171 d->d_type = ELF_T_BYTE; 172 d->d_version = LIBELF_PRIVATE(version); 173 174 (void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY); 175 176 return (d); 177} 178 179/* 180 * Retrieve a data descriptor for raw (untranslated) data for section 181 * `s'. 182 */ 183 184Elf_Data * 185elf_rawdata(Elf_Scn *s, Elf_Data *d) 186{ 187 Elf *e; 188 int elf_class; 189 uint32_t sh_type; 190 uint64_t sh_align, sh_offset, sh_size; 191 192 if (s == NULL || (e = s->s_elf) == NULL || 193 e->e_kind != ELF_K_ELF || e->e_rawfile == NULL) { 194 LIBELF_SET_ERROR(ARGUMENT, 0); 195 return (NULL); 196 } 197 198 if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL) 199 return (d); 200 201 if (d != NULL) 202 return (STAILQ_NEXT(d, d_next)); 203 204 elf_class = e->e_class; 205 206 assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64); 207 208 if (elf_class == ELFCLASS32) { 209 sh_type = s->s_shdr.s_shdr32.sh_type; 210 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset; 211 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size; 212 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign; 213 } else { 214 sh_type = s->s_shdr.s_shdr64.sh_type; 215 sh_offset = s->s_shdr.s_shdr64.sh_offset; 216 sh_size = s->s_shdr.s_shdr64.sh_size; 217 sh_align = s->s_shdr.s_shdr64.sh_addralign; 218 } 219 220 if (sh_type == SHT_NULL) 221 return (NULL); 222 223 if ((d = _libelf_allocate_data(s)) == NULL) 224 return (NULL); 225 226 d->d_buf = sh_type == SHT_NOBITS ? NULL : e->e_rawfile + sh_offset; 227 d->d_off = 0; 228 d->d_align = sh_align; 229 d->d_size = sh_size; 230 d->d_type = ELF_T_BYTE; 231 d->d_version = e->e_version; 232 233 STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next); 234 235 return (d); 236} 237