/* $NetBSD: elf_strptr.c,v 1.2 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_strptr.c,v 1.2.2.1.2.1 2009/10/25 01:10:29 kensmith Exp $"); */ #include #include #include #include "_libelf.h" /* * Convert an ELF section#,offset pair to a string pointer. */ char * elf_strptr(Elf *e, size_t scndx, size_t offset) { Elf_Scn *s; Elf_Data *d; size_t alignment, count; GElf_Shdr shdr; if (e == NULL || e->e_kind != ELF_K_ELF) { LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } if ((s = elf_getscn(e, scndx)) == NULL || gelf_getshdr(s, &shdr) == NULL) return (NULL); if (/*shdr.sh_type != SHT_STRTAB || */ offset >= shdr.sh_size) { LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } d = NULL; if (e->e_flags & ELF_F_LAYOUT) { /* * The application is taking responsibility for the * ELF object's layout, so we can directly translate * an offset to a `char *' address using the `d_off' * members of Elf_Data descriptors. */ while ((d = elf_getdata(s, d)) != NULL) { if (d->d_buf == 0 || d->d_size == 0) continue; if (d->d_type != ELF_T_BYTE) { LIBELF_SET_ERROR(DATA, 0); return (NULL); } if (offset >= d->d_off && offset < d->d_off + d->d_size) return ((char *) d->d_buf + offset - d->d_off); } } else { /* * Otherwise, the `d_off' members are not useable and * we need to compute offsets ourselves, taking into * account 'holes' in coverage of the section introduced * by alignment requirements. */ count = (size_t) 0; /* cumulative count of bytes seen */ while ((d = elf_getdata(s, d)) != NULL && count <= offset) { if (d->d_buf == NULL || d->d_size == 0) continue; if (d->d_type != ELF_T_BYTE) { LIBELF_SET_ERROR(DATA, 0); return (NULL); } if ((alignment = d->d_align) > 1) { if ((alignment & (alignment - 1)) != 0) { LIBELF_SET_ERROR(DATA, 0); return (NULL); } count = roundup2(count, alignment); } if (offset < count) { /* offset starts in the 'hole' */ LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); } if (offset < count + d->d_size) { if (d->d_buf != NULL) return ((char *) d->d_buf + offset - count); LIBELF_SET_ERROR(DATA, 0); return (NULL); } count += d->d_size; } } LIBELF_SET_ERROR(ARGUMENT, 0); return (NULL); }