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> 34164190Sjkoshy#include <stdlib.h> 35164190Sjkoshy 36164190Sjkoshy#include "_libelf.h" 37164190Sjkoshy 38164190Sjkoshy/* 39164190Sjkoshy * Load an ELF section table and create a list of Elf_Scn structures. 40164190Sjkoshy */ 41210330Skaiwint 42164190Sjkoshy_libelf_load_scn(Elf *e, void *ehdr) 43164190Sjkoshy{ 44164190Sjkoshy int ec, swapbytes; 45164190Sjkoshy size_t fsz, i, shnum; 46164190Sjkoshy uint64_t shoff; 47164190Sjkoshy char *src; 48164190Sjkoshy Elf32_Ehdr *eh32; 49164190Sjkoshy Elf64_Ehdr *eh64; 50164190Sjkoshy Elf_Scn *scn; 51210338Skaiw int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap); 52164190Sjkoshy 53164190Sjkoshy assert(e != NULL); 54164190Sjkoshy assert(ehdr != NULL); 55165535Sjkoshy assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0); 56164190Sjkoshy 57164190Sjkoshy#define CHECK_EHDR(E,EH) do { \ 58164190Sjkoshy if (fsz != (EH)->e_shentsize || \ 59164190Sjkoshy shoff + fsz * shnum > e->e_rawsize) { \ 60164190Sjkoshy LIBELF_SET_ERROR(HEADER, 0); \ 61164190Sjkoshy return (0); \ 62164190Sjkoshy } \ 63164190Sjkoshy } while (0) 64164190Sjkoshy 65165535Sjkoshy ec = e->e_class; 66165535Sjkoshy fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); 67164190Sjkoshy assert(fsz > 0); 68164190Sjkoshy 69165535Sjkoshy shnum = e->e_u.e_elf.e_nscn; 70165535Sjkoshy 71164190Sjkoshy if (ec == ELFCLASS32) { 72164190Sjkoshy eh32 = (Elf32_Ehdr *) ehdr; 73164190Sjkoshy shoff = (uint64_t) eh32->e_shoff; 74164190Sjkoshy CHECK_EHDR(e, eh32); 75164190Sjkoshy } else { 76164190Sjkoshy eh64 = (Elf64_Ehdr *) ehdr; 77164190Sjkoshy shoff = eh64->e_shoff; 78164190Sjkoshy CHECK_EHDR(e, eh64); 79164190Sjkoshy } 80164190Sjkoshy 81164190Sjkoshy xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); 82164190Sjkoshy 83164190Sjkoshy swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder); 84164190Sjkoshy src = e->e_rawfile + shoff; 85164190Sjkoshy 86165535Sjkoshy /* 87165535Sjkoshy * If the file is using extended numbering then section #0 88165535Sjkoshy * would have already been read in. 89165535Sjkoshy */ 90164190Sjkoshy 91165535Sjkoshy i = 0; 92165535Sjkoshy if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { 93165535Sjkoshy assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) == 94165535Sjkoshy STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next)); 95164190Sjkoshy 96165535Sjkoshy i = 1; 97164190Sjkoshy src += fsz; 98164190Sjkoshy } 99164190Sjkoshy 100164190Sjkoshy for (; i < shnum; i++, src += fsz) { 101164190Sjkoshy if ((scn = _libelf_allocate_scn(e, i)) == NULL) 102164190Sjkoshy return (0); 103164190Sjkoshy 104210338Skaiw (*xlator)((char *) &scn->s_shdr, sizeof(scn->s_shdr), src, 105210338Skaiw (size_t) 1, swapbytes); 106164190Sjkoshy 107164190Sjkoshy if (ec == ELFCLASS32) { 108164190Sjkoshy scn->s_offset = scn->s_rawoff = 109164190Sjkoshy scn->s_shdr.s_shdr32.sh_offset; 110164190Sjkoshy scn->s_size = scn->s_shdr.s_shdr32.sh_size; 111164190Sjkoshy } else { 112164190Sjkoshy scn->s_offset = scn->s_rawoff = 113164190Sjkoshy scn->s_shdr.s_shdr64.sh_offset; 114164190Sjkoshy scn->s_size = scn->s_shdr.s_shdr64.sh_size; 115164190Sjkoshy } 116164190Sjkoshy } 117165535Sjkoshy 118165535Sjkoshy e->e_flags |= LIBELF_F_SHDRS_LOADED; 119165535Sjkoshy 120164190Sjkoshy return (1); 121164190Sjkoshy} 122164190Sjkoshy 123164190Sjkoshy 124164190SjkoshyElf_Scn * 125164190Sjkoshyelf_getscn(Elf *e, size_t index) 126164190Sjkoshy{ 127164190Sjkoshy int ec; 128164190Sjkoshy void *ehdr; 129164190Sjkoshy Elf_Scn *s; 130164190Sjkoshy 131164190Sjkoshy if (e == NULL || e->e_kind != ELF_K_ELF || 132164190Sjkoshy ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) { 133164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 134164190Sjkoshy return (NULL); 135164190Sjkoshy } 136164190Sjkoshy 137164190Sjkoshy if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 138164190Sjkoshy return (NULL); 139164190Sjkoshy 140165535Sjkoshy if (e->e_cmd != ELF_C_WRITE && 141165535Sjkoshy (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && 142164190Sjkoshy _libelf_load_scn(e, ehdr) == 0) 143164190Sjkoshy return (NULL); 144164190Sjkoshy 145164190Sjkoshy STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) 146164190Sjkoshy if (s->s_ndx == index) 147164190Sjkoshy return (s); 148164190Sjkoshy 149164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 150164190Sjkoshy return (NULL); 151164190Sjkoshy} 152164190Sjkoshy 153164190Sjkoshysize_t 154164190Sjkoshyelf_ndxscn(Elf_Scn *s) 155164190Sjkoshy{ 156164190Sjkoshy if (s == NULL) { 157164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 158164190Sjkoshy return (SHN_UNDEF); 159164190Sjkoshy } 160164190Sjkoshy return (s->s_ndx); 161164190Sjkoshy} 162164190Sjkoshy 163164190SjkoshyElf_Scn * 164164190Sjkoshyelf_newscn(Elf *e) 165164190Sjkoshy{ 166164190Sjkoshy int ec; 167164190Sjkoshy void *ehdr; 168164190Sjkoshy Elf_Scn *scn; 169164190Sjkoshy 170164190Sjkoshy if (e == NULL || e->e_kind != ELF_K_ELF) { 171164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 172164190Sjkoshy return (NULL); 173164190Sjkoshy } 174164190Sjkoshy 175164190Sjkoshy if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { 176164190Sjkoshy LIBELF_SET_ERROR(CLASS, 0); 177164190Sjkoshy return (NULL); 178164190Sjkoshy } 179164190Sjkoshy 180164190Sjkoshy if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 181164190Sjkoshy return (NULL); 182164190Sjkoshy 183164190Sjkoshy /* 184164190Sjkoshy * The application may be asking for a new section descriptor 185164190Sjkoshy * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We 186164190Sjkoshy * need to bring in the existing section information before 187164190Sjkoshy * appending a new one to the list. 188164190Sjkoshy * 189164190Sjkoshy * Per the ELF(3) API, an application is allowed to open a 190164190Sjkoshy * file using ELF_C_READ, mess with its internal structure and 191164190Sjkoshy * use elf_update(...,ELF_C_NULL) to compute its new layout. 192164190Sjkoshy */ 193165535Sjkoshy if (e->e_cmd != ELF_C_WRITE && 194165535Sjkoshy (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && 195164190Sjkoshy _libelf_load_scn(e, ehdr) == 0) 196164190Sjkoshy return (NULL); 197164190Sjkoshy 198164190Sjkoshy if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { 199165535Sjkoshy assert(e->e_u.e_elf.e_nscn == 0); 200164190Sjkoshy if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) == 201164190Sjkoshy NULL) 202164190Sjkoshy return (NULL); 203165535Sjkoshy e->e_u.e_elf.e_nscn++; 204164190Sjkoshy } 205164190Sjkoshy 206165535Sjkoshy assert(e->e_u.e_elf.e_nscn > 0); 207164190Sjkoshy 208165535Sjkoshy if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL) 209164190Sjkoshy return (NULL); 210164190Sjkoshy 211165535Sjkoshy e->e_u.e_elf.e_nscn++; 212164190Sjkoshy 213164190Sjkoshy (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY); 214164190Sjkoshy 215164190Sjkoshy return (scn); 216164190Sjkoshy} 217164190Sjkoshy 218164190SjkoshyElf_Scn * 219164190Sjkoshyelf_nextscn(Elf *e, Elf_Scn *s) 220164190Sjkoshy{ 221164190Sjkoshy if (e == NULL || (e->e_kind != ELF_K_ELF) || 222164190Sjkoshy (s && s->s_elf != e)) { 223164190Sjkoshy LIBELF_SET_ERROR(ARGUMENT, 0); 224164190Sjkoshy return (NULL); 225164190Sjkoshy } 226164190Sjkoshy 227164190Sjkoshy return (s == NULL ? elf_getscn(e, (size_t) 1) : 228164190Sjkoshy STAILQ_NEXT(s, s_next)); 229164190Sjkoshy} 230