lib/libelf/elf_data.c

   1 /*-
   2  * Copyright (c) 2006,2008,2011 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 <assert.h>
  28 #include <errno.h>
  29 #include <libelf.h>
  30 #include <stdlib.h>
  31
  32 #include "_libelf.h"
  33
  34 LIBELF_VCSID("$Id$");
  35
  36 Elf_Data *
  37 elf_getdata(Elf_Scn *s, Elf_Data *d)
  38 {
  39         Elf *e;
  40         size_t fsz, msz, count;
  41         int elfclass, elftype;
  42         unsigned int sh_type;
  43         uint64_t sh_align, sh_offset, sh_size;
  44         int (*xlate)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
  45
  46         if (s == NULL || (e = s->s_elf) == NULL ||
  47             (d != NULL && s != d->d_scn)) {
  48                 LIBELF_SET_ERROR(ARGUMENT, 0);
  49                 return (NULL);
  50         }
  51
  52         assert(e->e_kind == ELF_K_ELF);
  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(ARGUMENT, 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 || sh_size == 0) {
 119                 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
 120                 return (d);
 121         }
 122
 123         if ((d->d_buf = malloc(msz*count)) == NULL) {
 124                 (void) _libelf_release_data(d);
 125                 LIBELF_SET_ERROR(RESOURCE, 0);
 126                 return (NULL);
 127         }
 128
 129         d->d_flags  |= LIBELF_F_DATA_MALLOCED;
 130
 131         xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass);
 132         if (!(*xlate)(d->d_buf, d->d_size, e->e_rawfile + sh_offset, count,
 133             e->e_byteorder != LIBELF_PRIVATE(byteorder))) {
 134                 _libelf_release_data(d);
 135                 LIBELF_SET_ERROR(DATA, 0);
 136                 return (NULL);
 137         }
 138
 139         STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
 140
 141         return (d);
 142 }
 143
 144 Elf_Data *
 145 elf_newdata(Elf_Scn *s)
 146 {
 147         Elf *e;
 148         Elf_Data *d;
 149
 150         if (s == NULL || (e = s->s_elf) == NULL) {
 151                 LIBELF_SET_ERROR(ARGUMENT, 0);
 152                 return (NULL);
 153         }
 154
 155         assert(e->e_kind == ELF_K_ELF);
 156
 157         /*
 158          * elf_newdata() has to append a data descriptor, so
 159          * bring in existing section data if not already present.
 160          */
 161         if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data))
 162                 if (elf_getdata(s, NULL) == NULL)
 163                         return (NULL);
 164
 165         if ((d = _libelf_allocate_data(s)) == NULL)
 166                 return (NULL);
 167
 168         STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
 169
 170         d->d_align = 1;
 171         d->d_buf = NULL;
 172         d->d_off = (uint64_t) ~0;
 173         d->d_size = 0;
 174         d->d_type = ELF_T_BYTE;
 175         d->d_version = LIBELF_PRIVATE(version);
 176
 177         (void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY);
 178
 179         return (d);
 180 }
 181
 182 /*
 183  * Retrieve a data descriptor for raw (untranslated) data for section
 184  * `s'.
 185  */
 186
 187 Elf_Data *
 188 elf_rawdata(Elf_Scn *s, Elf_Data *d)
 189 {
 190         Elf *e;
 191         int elf_class;
 192         uint32_t sh_type;
 193         uint64_t sh_align, sh_offset, sh_size;
 194
 195         if (s == NULL || (e = s->s_elf) == NULL || e->e_rawfile == NULL) {
 196                 LIBELF_SET_ERROR(ARGUMENT, 0);
 197                 return (NULL);
 198         }
 199
 200         assert(e->e_kind == ELF_K_ELF);
 201
 202         if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL)
 203                 return (d);
 204
 205         if (d != NULL)
 206                 return (STAILQ_NEXT(d, d_next));
 207
 208         elf_class = e->e_class;
 209
 210         assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64);
 211
 212         if (elf_class == ELFCLASS32) {
 213                 sh_type   = s->s_shdr.s_shdr32.sh_type;
 214                 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
 215                 sh_size   = (uint64_t) s->s_shdr.s_shdr32.sh_size;
 216                 sh_align  = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
 217         } else {
 218                 sh_type   = s->s_shdr.s_shdr64.sh_type;
 219                 sh_offset = s->s_shdr.s_shdr64.sh_offset;
 220                 sh_size   = s->s_shdr.s_shdr64.sh_size;
 221                 sh_align  = s->s_shdr.s_shdr64.sh_addralign;
 222         }
 223
 224         if (sh_type == SHT_NULL)
 225                 return (NULL);
 226
 227         if ((d = _libelf_allocate_data(s)) == NULL)
 228                 return (NULL);
 229
 230         d->d_buf     = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
 231             e->e_rawfile + sh_offset;
 232         d->d_off     = 0;
 233         d->d_align   = sh_align;
 234         d->d_size    = sh_size;
 235         d->d_type    = ELF_T_BYTE;
 236         d->d_version = e->e_version;
 237
 238         STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);
 239
 240         return (d);
 241 }