1164190Sjkoshy/*- 2164190Sjkoshy * Copyright (c) 2006 Joseph Koshy 3164190Sjkoshy * All rights reserved. 4164190Sjkoshy * 5164190Sjkoshy * Redistribution and use in source and binary forms, with or without 6164190Sjkoshy * modification, are permitted provided that the following conditions 7164190Sjkoshy * are met: 8164190Sjkoshy * 1. Redistributions of source code must retain the above copyright 9164190Sjkoshy * notice, this list of conditions and the following disclaimer. 10164190Sjkoshy * 2. Redistributions in binary form must reproduce the above copyright 11164190Sjkoshy * notice, this list of conditions and the following disclaimer in the 12164190Sjkoshy * documentation and/or other materials provided with the distribution. 13164190Sjkoshy * 14164190Sjkoshy * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15164190Sjkoshy * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16164190Sjkoshy * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17164190Sjkoshy * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18164190Sjkoshy * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19164190Sjkoshy * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20164190Sjkoshy * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21164190Sjkoshy * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22164190Sjkoshy * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23164190Sjkoshy * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24164190Sjkoshy * SUCH DAMAGE. 25164190Sjkoshy */ 26164190Sjkoshy 27164190Sjkoshy#include <sys/cdefs.h> 28164190Sjkoshy__FBSDID("$FreeBSD$"); 29164190Sjkoshy 30164190Sjkoshy#include <assert.h> 31164190Sjkoshy#include <errno.h> 32164190Sjkoshy#include <gelf.h> 33164190Sjkoshy#include <libelf.h> 34277558Semaste#include <stdint.h> 35164190Sjkoshy#include <stdlib.h> 36164190Sjkoshy 37164190Sjkoshy#include "_libelf.h" 38164190Sjkoshy 39164190Sjkoshy/* 40164190Sjkoshy * Load an ELF section table and create a list of Elf_Scn structures. 41164190Sjkoshy */ 42210330Skaiwint 43164190Sjkoshy_libelf_load_scn(Elf *e, void *ehdr) 44164190Sjkoshy{ 45164190Sjkoshy int ec, swapbytes; 46164190Sjkoshy size_t fsz, i, shnum; 47164190Sjkoshy uint64_t shoff; 48164190Sjkoshy char *src; 49164190Sjkoshy Elf32_Ehdr *eh32; 50164190Sjkoshy Elf64_Ehdr *eh64; 51164190Sjkoshy Elf_Scn *scn; 52210338Skaiw int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap); 53164190Sjkoshy 54164190Sjkoshy assert(e != NULL); 55164190Sjkoshy assert(ehdr != NULL); 56165535Sjkoshy assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0); 57164190Sjkoshy 58164190Sjkoshy#define CHECK_EHDR(E,EH) do { \ 59277558Semaste if (shoff > e->e_rawsize || \ 60277558Semaste fsz != (EH)->e_shentsize || \ 61277558Semaste shnum > SIZE_MAX / fsz || \ 62277558Semaste fsz * shnum > e->e_rawsize - shoff) { \ 63164190Sjkoshy LIBELF_SET_ERROR(HEADER, 0); \ 64164190Sjkoshy return (0); \ 65164190Sjkoshy } \ 66164190Sjkoshy } while (0) 67164190Sjkoshy 68165535Sjkoshy ec = e->e_class; 69165535Sjkoshy fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); 70164190Sjkoshy assert(fsz > 0); 71164190Sjkoshy 72165535Sjkoshy shnum = e->e_u.e_elf.e_nscn; 73165535Sjkoshy 74164190Sjkoshy if (ec == ELFCLASS32) { 75164190Sjkoshy eh32 = (Elf32_Ehdr *) ehdr; 76164190Sjkoshy shoff = (uint64_t) eh32->e_shoff; 77164190Sjkoshy CHECK_EHDR(e, eh32); 78164190Sjkoshy } else { 79164190Sjkoshy eh64 = (Elf64_Ehdr *) ehdr; 80164190Sjkoshy shoff = eh64->e_shoff; 81164190Sjkoshy CHECK_EHDR(e, eh64); 82164190Sjkoshy } 83164190Sjkoshy 84164190Sjkoshy xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); 85164190Sjkoshy 86164190Sjkoshy swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder); 87164190Sjkoshy src = e->e_rawfile + shoff; 88164190Sjkoshy 89165535Sjkoshy /* 90165535Sjkoshy * If the file is using extended numbering then section #0 91165535Sjkoshy * would have already been read in. 92165535Sjkoshy */ 93164190Sjkoshy 94165535Sjkoshy i = 0; 95165535Sjkoshy if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { 96165535Sjkoshy assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) == 97165535Sjkoshy STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next)); 98164190Sjkoshy 99165535Sjkoshy i = 1; 100164190Sjkoshy src += fsz; 101164190Sjkoshy } 102164190Sjkoshy 103164190Sjkoshy for (; i < shnum; i++, src += fsz) { 104164190Sjkoshy if ((scn = _libelf_allocate_scn(e, i)) == NULL) 105164190Sjkoshy return (0); 106164190Sjkoshy 107210338Skaiw (*xlator)((char *) &scn->s_shdr, sizeof(scn->s_shdr), src, 108210338Skaiw (size_t) 1, swapbytes); 109164190Sjkoshy 110164190Sjkoshy if (ec == ELFCLASS32) { 111164190Sjkoshy scn->s_offset = scn->s_rawoff = 112164190Sjkoshy scn->s_shdr.s_shdr32.sh_offset; 113164190Sjkoshy scn->s_size = scn->s_shdr.s_shdr32.sh_size; 114164190Sjkoshy } else { 115164190Sjkoshy scn->s_offset = scn->s_rawoff = 116164190Sjkoshy scn->s_shdr.s_shdr64.sh_offset; 117164190Sjkoshy scn->s_size = scn->s_shdr.s_shdr64.sh_size; 118164190Sjkoshy } 119164190Sjkoshy } 120165535Sjkoshy 121165535Sjkoshy e->e_flags |= LIBELF_F_SHDRS_LOADED; 122165535Sjkoshy 123164190Sjkoshy return (1); 124164190Sjkoshy} 125164190Sjkoshy 126164190Sjkoshy 127164190SjkoshyElf_Scn * 128164190Sjkoshyelf_getscn(Elf *e, size_t index) 129164190Sjkoshy{ 130164190Sjkoshy int ec; 131164190Sjkoshy void *ehdr; 132164190Sjkoshy Elf_Scn *s; 133164190Sjkoshy 134164190Sjkoshy if (e == NULL || e->e_kind != ELF_K_ELF || 135164190Sjkoshy ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) { 136164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 137164190Sjkoshy return (NULL); 138164190Sjkoshy } 139164190Sjkoshy 140164190Sjkoshy if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 141164190Sjkoshy return (NULL); 142164190Sjkoshy 143165535Sjkoshy if (e->e_cmd != ELF_C_WRITE && 144165535Sjkoshy (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && 145164190Sjkoshy _libelf_load_scn(e, ehdr) == 0) 146164190Sjkoshy return (NULL); 147164190Sjkoshy 148164190Sjkoshy STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) 149164190Sjkoshy if (s->s_ndx == index) 150164190Sjkoshy return (s); 151164190Sjkoshy 152164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 153164190Sjkoshy return (NULL); 154164190Sjkoshy} 155164190Sjkoshy 156164190Sjkoshysize_t 157164190Sjkoshyelf_ndxscn(Elf_Scn *s) 158164190Sjkoshy{ 159164190Sjkoshy if (s == NULL) { 160164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 161164190Sjkoshy return (SHN_UNDEF); 162164190Sjkoshy } 163164190Sjkoshy return (s->s_ndx); 164164190Sjkoshy} 165164190Sjkoshy 166164190SjkoshyElf_Scn * 167164190Sjkoshyelf_newscn(Elf *e) 168164190Sjkoshy{ 169164190Sjkoshy int ec; 170164190Sjkoshy void *ehdr; 171164190Sjkoshy Elf_Scn *scn; 172164190Sjkoshy 173164190Sjkoshy if (e == NULL || e->e_kind != ELF_K_ELF) { 174164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 175164190Sjkoshy return (NULL); 176164190Sjkoshy } 177164190Sjkoshy 178164190Sjkoshy if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { 179164190Sjkoshy LIBELF_SET_ERROR(CLASS, 0); 180164190Sjkoshy return (NULL); 181164190Sjkoshy } 182164190Sjkoshy 183164190Sjkoshy if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 184164190Sjkoshy return (NULL); 185164190Sjkoshy 186164190Sjkoshy /* 187164190Sjkoshy * The application may be asking for a new section descriptor 188164190Sjkoshy * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We 189164190Sjkoshy * need to bring in the existing section information before 190164190Sjkoshy * appending a new one to the list. 191164190Sjkoshy * 192164190Sjkoshy * Per the ELF(3) API, an application is allowed to open a 193164190Sjkoshy * file using ELF_C_READ, mess with its internal structure and 194164190Sjkoshy * use elf_update(...,ELF_C_NULL) to compute its new layout. 195164190Sjkoshy */ 196165535Sjkoshy if (e->e_cmd != ELF_C_WRITE && 197165535Sjkoshy (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && 198164190Sjkoshy _libelf_load_scn(e, ehdr) == 0) 199164190Sjkoshy return (NULL); 200164190Sjkoshy 201164190Sjkoshy if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { 202165535Sjkoshy assert(e->e_u.e_elf.e_nscn == 0); 203164190Sjkoshy if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) == 204164190Sjkoshy NULL) 205164190Sjkoshy return (NULL); 206165535Sjkoshy e->e_u.e_elf.e_nscn++; 207164190Sjkoshy } 208164190Sjkoshy 209165535Sjkoshy assert(e->e_u.e_elf.e_nscn > 0); 210164190Sjkoshy 211165535Sjkoshy if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL) 212164190Sjkoshy return (NULL); 213164190Sjkoshy 214165535Sjkoshy e->e_u.e_elf.e_nscn++; 215164190Sjkoshy 216164190Sjkoshy (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY); 217164190Sjkoshy 218164190Sjkoshy return (scn); 219164190Sjkoshy} 220164190Sjkoshy 221164190SjkoshyElf_Scn * 222164190Sjkoshyelf_nextscn(Elf *e, Elf_Scn *s) 223164190Sjkoshy{ 224164190Sjkoshy if (e == NULL || (e->e_kind != ELF_K_ELF) || 225164190Sjkoshy (s && s->s_elf != e)) { 226164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 227164190Sjkoshy return (NULL); 228164190Sjkoshy } 229164190Sjkoshy 230164190Sjkoshy return (s == NULL ? elf_getscn(e, (size_t) 1) : 231164190Sjkoshy STAILQ_NEXT(s, s_next)); 232164190Sjkoshy} 233