elf_scn.c revision 4484
14484Sbinkertn@umich.edu/*- 24484Sbinkertn@umich.edu * Copyright (c) 2006 Joseph Koshy 34484Sbinkertn@umich.edu * All rights reserved. 44484Sbinkertn@umich.edu * 54484Sbinkertn@umich.edu * Redistribution and use in source and binary forms, with or without 64484Sbinkertn@umich.edu * modification, are permitted provided that the following conditions 74484Sbinkertn@umich.edu * are met: 84484Sbinkertn@umich.edu * 1. Redistributions of source code must retain the above copyright 94484Sbinkertn@umich.edu * notice, this list of conditions and the following disclaimer. 104484Sbinkertn@umich.edu * 2. Redistributions in binary form must reproduce the above copyright 114484Sbinkertn@umich.edu * notice, this list of conditions and the following disclaimer in the 124484Sbinkertn@umich.edu * documentation and/or other materials provided with the distribution. 134484Sbinkertn@umich.edu * 144484Sbinkertn@umich.edu * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 154484Sbinkertn@umich.edu * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 164484Sbinkertn@umich.edu * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 174484Sbinkertn@umich.edu * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 184484Sbinkertn@umich.edu * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 194484Sbinkertn@umich.edu * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 204484Sbinkertn@umich.edu * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 214484Sbinkertn@umich.edu * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 224484Sbinkertn@umich.edu * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 234484Sbinkertn@umich.edu * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 244484Sbinkertn@umich.edu * SUCH DAMAGE. 254484Sbinkertn@umich.edu */ 264484Sbinkertn@umich.edu 274484Sbinkertn@umich.edu 284484Sbinkertn@umich.edu#include <assert.h> 294484Sbinkertn@umich.edu#include <errno.h> 304484Sbinkertn@umich.edu#include <stddef.h> 314484Sbinkertn@umich.edu#include <stdlib.h> 324484Sbinkertn@umich.edu 334484Sbinkertn@umich.edu#include "gelf.h" 344484Sbinkertn@umich.edu#include "libelf.h" 354484Sbinkertn@umich.edu#include "_libelf.h" 364484Sbinkertn@umich.edu 374484Sbinkertn@umich.edu/* 384484Sbinkertn@umich.edu * Load an ELF section table and create a list of Elf_Scn structures. 394484Sbinkertn@umich.edu */ 404484Sbinkertn@umich.edustatic int 414484Sbinkertn@umich.edu_libelf_load_scn(Elf *e, void *ehdr) 424484Sbinkertn@umich.edu{ 434484Sbinkertn@umich.edu int ec, swapbytes; 444484Sbinkertn@umich.edu size_t fsz, i, shnum; 454484Sbinkertn@umich.edu uint64_t shoff; 464484Sbinkertn@umich.edu char *src; 474484Sbinkertn@umich.edu Elf32_Ehdr *eh32; 484484Sbinkertn@umich.edu Elf64_Ehdr *eh64; 494484Sbinkertn@umich.edu Elf_Scn *scn; 504484Sbinkertn@umich.edu void (*xlator)(char *_d, char *_s, size_t _c, int _swap); 514484Sbinkertn@umich.edu 524484Sbinkertn@umich.edu assert(e != NULL); 534484Sbinkertn@umich.edu assert(ehdr != NULL); 544484Sbinkertn@umich.edu assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0); 554484Sbinkertn@umich.edu 564484Sbinkertn@umich.edu#define CHECK_EHDR(E,EH) do { \ 574484Sbinkertn@umich.edu if (fsz != (EH)->e_shentsize || \ 584484Sbinkertn@umich.edu shoff + fsz * shnum > e->e_rawsize) { \ 594484Sbinkertn@umich.edu LIBELF_SET_ERROR(HEADER, 0); \ 604484Sbinkertn@umich.edu return (0); \ 614484Sbinkertn@umich.edu } \ 624484Sbinkertn@umich.edu } while (0) 634484Sbinkertn@umich.edu 644484Sbinkertn@umich.edu ec = e->e_class; 654484Sbinkertn@umich.edu fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); 664484Sbinkertn@umich.edu assert(fsz > 0); 674484Sbinkertn@umich.edu 684484Sbinkertn@umich.edu shnum = e->e_u.e_elf.e_nscn; 694484Sbinkertn@umich.edu 704484Sbinkertn@umich.edu if (ec == ELFCLASS32) { 714484Sbinkertn@umich.edu eh32 = (Elf32_Ehdr *) ehdr; 724484Sbinkertn@umich.edu shoff = (uint64_t) eh32->e_shoff; 734484Sbinkertn@umich.edu CHECK_EHDR(e, eh32); 744484Sbinkertn@umich.edu } else { 754484Sbinkertn@umich.edu eh64 = (Elf64_Ehdr *) ehdr; 764484Sbinkertn@umich.edu shoff = eh64->e_shoff; 774484Sbinkertn@umich.edu CHECK_EHDR(e, eh64); 784484Sbinkertn@umich.edu } 794484Sbinkertn@umich.edu 804484Sbinkertn@umich.edu xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); 814484Sbinkertn@umich.edu 824484Sbinkertn@umich.edu swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder); 834484Sbinkertn@umich.edu src = e->e_rawfile + shoff; 844484Sbinkertn@umich.edu 854484Sbinkertn@umich.edu /* 864484Sbinkertn@umich.edu * If the file is using extended numbering then section #0 874484Sbinkertn@umich.edu * would have already been read in. 884484Sbinkertn@umich.edu */ 894484Sbinkertn@umich.edu 904484Sbinkertn@umich.edu i = 0; 914484Sbinkertn@umich.edu if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { 924484Sbinkertn@umich.edu assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) == 934484Sbinkertn@umich.edu STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next)); 944484Sbinkertn@umich.edu 954484Sbinkertn@umich.edu i = 1; 964484Sbinkertn@umich.edu src += fsz; 974484Sbinkertn@umich.edu } 984484Sbinkertn@umich.edu 994484Sbinkertn@umich.edu for (; i < shnum; i++, src += fsz) { 1004484Sbinkertn@umich.edu if ((scn = _libelf_allocate_scn(e, i)) == NULL) 1014484Sbinkertn@umich.edu return (0); 1024484Sbinkertn@umich.edu 1034484Sbinkertn@umich.edu (*xlator)((char *) &scn->s_shdr, src, (size_t) 1, swapbytes); 1044484Sbinkertn@umich.edu 1054484Sbinkertn@umich.edu if (ec == ELFCLASS32) { 1064484Sbinkertn@umich.edu scn->s_offset = scn->s_rawoff = 1074484Sbinkertn@umich.edu scn->s_shdr.s_shdr32.sh_offset; 1084484Sbinkertn@umich.edu scn->s_size = scn->s_shdr.s_shdr32.sh_size; 1094484Sbinkertn@umich.edu } else { 1104484Sbinkertn@umich.edu scn->s_offset = scn->s_rawoff = 1114484Sbinkertn@umich.edu scn->s_shdr.s_shdr64.sh_offset; 1124484Sbinkertn@umich.edu scn->s_size = scn->s_shdr.s_shdr64.sh_size; 1134484Sbinkertn@umich.edu } 1144484Sbinkertn@umich.edu } 1154484Sbinkertn@umich.edu 1164484Sbinkertn@umich.edu e->e_flags |= LIBELF_F_SHDRS_LOADED; 1174484Sbinkertn@umich.edu 1184484Sbinkertn@umich.edu return (1); 1194484Sbinkertn@umich.edu} 1204484Sbinkertn@umich.edu 1214484Sbinkertn@umich.edu 1224484Sbinkertn@umich.eduElf_Scn * 1234484Sbinkertn@umich.eduelf_getscn(Elf *e, size_t index) 1244484Sbinkertn@umich.edu{ 1254484Sbinkertn@umich.edu int ec; 1264484Sbinkertn@umich.edu void *ehdr; 1274484Sbinkertn@umich.edu Elf_Scn *s; 1284484Sbinkertn@umich.edu 1294484Sbinkertn@umich.edu if (e == NULL || e->e_kind != ELF_K_ELF || 1304484Sbinkertn@umich.edu ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) { 1314484Sbinkertn@umich.edu LIBELF_SET_ERROR(ARGUMENT, 0); 1324484Sbinkertn@umich.edu return (NULL); 1334484Sbinkertn@umich.edu } 1344484Sbinkertn@umich.edu 1354484Sbinkertn@umich.edu if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 1364484Sbinkertn@umich.edu return (NULL); 1374484Sbinkertn@umich.edu 1384484Sbinkertn@umich.edu if (e->e_cmd != ELF_C_WRITE && 1394484Sbinkertn@umich.edu (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && 1404484Sbinkertn@umich.edu _libelf_load_scn(e, ehdr) == 0) 1414484Sbinkertn@umich.edu return (NULL); 1424484Sbinkertn@umich.edu 1434484Sbinkertn@umich.edu STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) 1444484Sbinkertn@umich.edu if (s->s_ndx == index) 1454484Sbinkertn@umich.edu return (s); 1464484Sbinkertn@umich.edu 1474484Sbinkertn@umich.edu LIBELF_SET_ERROR(ARGUMENT, 0); 1484484Sbinkertn@umich.edu return (NULL); 1494484Sbinkertn@umich.edu} 1504484Sbinkertn@umich.edu 1514484Sbinkertn@umich.edusize_t 1524484Sbinkertn@umich.eduelf_ndxscn(Elf_Scn *s) 1534484Sbinkertn@umich.edu{ 1544484Sbinkertn@umich.edu if (s == NULL) { 1554484Sbinkertn@umich.edu LIBELF_SET_ERROR(ARGUMENT, 0); 1564484Sbinkertn@umich.edu return (SHN_UNDEF); 1574484Sbinkertn@umich.edu } 1584484Sbinkertn@umich.edu return (s->s_ndx); 1594484Sbinkertn@umich.edu} 1604484Sbinkertn@umich.edu 1614484Sbinkertn@umich.eduElf_Scn * 1624484Sbinkertn@umich.eduelf_newscn(Elf *e) 1634484Sbinkertn@umich.edu{ 1644484Sbinkertn@umich.edu int ec; 1654484Sbinkertn@umich.edu void *ehdr; 1664484Sbinkertn@umich.edu Elf_Scn *scn; 1674484Sbinkertn@umich.edu 1684484Sbinkertn@umich.edu if (e == NULL || e->e_kind != ELF_K_ELF) { 1694484Sbinkertn@umich.edu LIBELF_SET_ERROR(ARGUMENT, 0); 1704484Sbinkertn@umich.edu return (NULL); 1714484Sbinkertn@umich.edu } 1724484Sbinkertn@umich.edu 1734484Sbinkertn@umich.edu if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { 1744484Sbinkertn@umich.edu LIBELF_SET_ERROR(CLASS, 0); 1754484Sbinkertn@umich.edu return (NULL); 1764484Sbinkertn@umich.edu } 1774484Sbinkertn@umich.edu 1784484Sbinkertn@umich.edu if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) 1794484Sbinkertn@umich.edu return (NULL); 1804484Sbinkertn@umich.edu 1814484Sbinkertn@umich.edu /* 1824484Sbinkertn@umich.edu * The application may be asking for a new section descriptor 1834484Sbinkertn@umich.edu * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We 1844484Sbinkertn@umich.edu * need to bring in the existing section information before 1854484Sbinkertn@umich.edu * appending a new one to the list. 1864484Sbinkertn@umich.edu * 1874484Sbinkertn@umich.edu * Per the ELF(3) API, an application is allowed to open a 1884484Sbinkertn@umich.edu * file using ELF_C_READ, mess with its internal structure and 1894484Sbinkertn@umich.edu * use elf_update(...,ELF_C_NULL) to compute its new layout. 1904484Sbinkertn@umich.edu */ 1914484Sbinkertn@umich.edu if (e->e_cmd != ELF_C_WRITE && 1924484Sbinkertn@umich.edu (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && 1934484Sbinkertn@umich.edu _libelf_load_scn(e, ehdr) == 0) 1944484Sbinkertn@umich.edu return (NULL); 1954484Sbinkertn@umich.edu 1964484Sbinkertn@umich.edu if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { 1974484Sbinkertn@umich.edu assert(e->e_u.e_elf.e_nscn == 0); 1984484Sbinkertn@umich.edu if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) == 1994484Sbinkertn@umich.edu NULL) 2004484Sbinkertn@umich.edu return (NULL); 2014484Sbinkertn@umich.edu e->e_u.e_elf.e_nscn++; 2024484Sbinkertn@umich.edu } 2034484Sbinkertn@umich.edu 2044484Sbinkertn@umich.edu assert(e->e_u.e_elf.e_nscn > 0); 2054484Sbinkertn@umich.edu 2064484Sbinkertn@umich.edu if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL) 2074484Sbinkertn@umich.edu return (NULL); 2084484Sbinkertn@umich.edu 2094484Sbinkertn@umich.edu e->e_u.e_elf.e_nscn++; 2104484Sbinkertn@umich.edu 2114484Sbinkertn@umich.edu (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY); 2124484Sbinkertn@umich.edu 2134484Sbinkertn@umich.edu return (scn); 2144484Sbinkertn@umich.edu} 2154484Sbinkertn@umich.edu 2164484Sbinkertn@umich.eduElf_Scn * 2174484Sbinkertn@umich.eduelf_nextscn(Elf *e, Elf_Scn *s) 2184484Sbinkertn@umich.edu{ 2194484Sbinkertn@umich.edu if (e == NULL || (e->e_kind != ELF_K_ELF) || 2204484Sbinkertn@umich.edu (s && s->s_elf != e)) { 2214484Sbinkertn@umich.edu LIBELF_SET_ERROR(ARGUMENT, 0); 2224484Sbinkertn@umich.edu return (NULL); 2234484Sbinkertn@umich.edu } 2244484Sbinkertn@umich.edu 2254484Sbinkertn@umich.edu return (s == NULL ? elf_getscn(e, (size_t) 1) : 2264484Sbinkertn@umich.edu STAILQ_NEXT(s, s_next)); 2274484Sbinkertn@umich.edu} 228