/* $NetBSD: elf_scn.c,v 1.6 2010/02/22 10:48:32 darran Exp $ */ /*- * Copyright (c) 2006 Joseph Koshy * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if HAVE_NBTOOL_CONFIG_H # include "nbtool_config.h" #endif #include /* __FBSDID("$FreeBSD: src/lib/libelf/elf_scn.c,v 1.2.10.1.2.1 2009/10/25 01:10:29 kensmith Exp $"); */ #include #include #include #include #include #include #include #include "_libelf.h" /* * Load an ELF section table and create a list of Elf_Scn structures. */ static int _libelf_load_scn(Elf *e, void *ehdr) { int ec, swapbytes; size_t fsz, i, shnum; uint64_t shoff; char *src; Elf32_Ehdr *eh32; Elf64_Ehdr *eh64; Elf_Scn *scn; void (*xlator)(char *_d, char *_s, size_t _c, int _swap); assert(e != NULL); assert(ehdr != NULL); assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0); #define CHECK_EHDR(E,EH) do { \ if (fsz != (EH)->e_shentsize || \ shoff + fsz * shnum > e->e_rawsize) { \ LIBELF_SET_ERROR(HEADER, 0); \ return (0); \ } \ } while (/*CONSTCOND*/0) ec = e->e_class; fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); assert(fsz > 0); shnum = e->e_u.e_elf.e_nscn; if (ec == ELFCLASS32) { eh32 = (Elf32_Ehdr *) ehdr; shoff = (uint64_t) eh32->e_shoff; CHECK_EHDR(e, eh32); } else { eh64 = (Elf64_Ehdr *) ehdr; shoff = eh64->e_shoff; CHECK_EHDR(e, eh64); } xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); swapbytes = e->e_byteorder != _libelf_host_byteorder(); if (shoff > SSIZE_MAX) { LIBELF_SET_ERROR(HEADER, 0); return (0); } src = e->e_rawfile + (ssize_t)shoff; /* * If the file is using extended numbering then section #0 * would have already been read in. */ i = 0; if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) == STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next)); i = 1; src += fsz; } for (; i < shnum; i++, src += fsz) { if ((scn = _libelf_allocate_scn(e, i)) == NULL) return (0); (*xlator)((void *) &scn->s_shdr, src, (size_t) 1, swapbytes); if (ec == ELFCLASS32) { scn->s_offset = scn->s_rawoff = scn->s_shdr.s_shdr32.sh_offset; scn->s_size = scn->s_shdr.s_shdr32.sh_size; } else { scn->s_offset = scn->s_rawoff = scn->s_shdr.s_shdr64.sh_offset; scn->s_size = scn->s_shdr.s_shdr64.sh_size; } } e->e_flags |= LIBELF_F_SHDRS_LOADED; return (1); } Elf_Scn * elf_getscn(Elf *e, size_t index) { int ec; void *ehdr; Elf_Scn *s; if (e == NULL || e->e_kind != ELF_K_ELF || ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) { LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) return (NULL); if (e->e_cmd != ELF_C_WRITE && (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && _libelf_load_scn(e, ehdr) == 0) return (NULL); STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) if (s->s_ndx == index) return (s); LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } size_t elf_ndxscn(Elf_Scn *s) { if (s == NULL) { LIBELF_SET_ERROR(ARGUMENT, 0); return (SHN_UNDEF); } return (s->s_ndx); } Elf_Scn * elf_newscn(Elf *e) { int ec; void *ehdr; Elf_Scn *scn; if (e == NULL || e->e_kind != ELF_K_ELF) { LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { LIBELF_SET_ERROR(CLASS, 0); return (NULL); } if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) return (NULL); /* * The application may be asking for a new section descriptor * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We * need to bring in the existing section information before * appending a new one to the list. * * Per the ELF(3) API, an application is allowed to open a * file using ELF_C_READ, mess with its internal structure and * use elf_update(...,ELF_C_NULL) to compute its new layout. */ if (e->e_cmd != ELF_C_WRITE && (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && _libelf_load_scn(e, ehdr) == 0) return (NULL); if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { assert(e->e_u.e_elf.e_nscn == 0); if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) == NULL) return (NULL); e->e_u.e_elf.e_nscn++; } assert(e->e_u.e_elf.e_nscn > 0); if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL) return (NULL); e->e_u.e_elf.e_nscn++; (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY); return (scn); } Elf_Scn * elf_nextscn(Elf *e, Elf_Scn *s) { if (e == NULL || (e->e_kind != ELF_K_ELF) || (s && s->s_elf != e)) { LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } return (s == NULL ? elf_getscn(e, (size_t) 1) : STAILQ_NEXT(s, s_next)); }