/* $NetBSD: libelf_checksum.c,v 1.2 2010/02/22 10:48:33 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/libelf_checksum.c,v 1.2.10.1.2.1 2009/10/25 01:10:29 kensmith Exp $"); */ #include #include "_libelf.h" static unsigned long _libelf_sum(unsigned long c, const unsigned char *s, size_t size) { if (s == NULL || size == 0) return (c); while (size--) c += *s++; return (c); } unsigned long _libelf_checksum(Elf *e, int elfclass) { size_t shn; Elf_Scn *scn; Elf_Data *d; unsigned long checksum; GElf_Ehdr eh; GElf_Shdr shdr; if (e == NULL) { LIBELF_SET_ERROR(ARGUMENT, 0); return (0L); } if (e->e_class != elfclass) { LIBELF_SET_ERROR(CLASS, 0); return (0L); } if (gelf_getehdr(e, &eh) == NULL) return (0); /* * Iterate over all sections in the ELF file, computing the * checksum along the way. * * The first section is always SHN_UNDEF and can be skipped. * Non-allocatable sections are skipped, as are sections that * could be affected by utilities such as strip(1). */ checksum = 0; for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) { if ((scn = elf_getscn(e, shn)) == NULL) return (0); if (gelf_getshdr(scn, &shdr) == NULL) return (0); if ((shdr.sh_flags & SHF_ALLOC) == 0 || shdr.sh_type == SHT_DYNAMIC || shdr.sh_type == SHT_DYNSYM) continue; d = NULL; while ((d = elf_rawdata(scn, d)) != NULL) checksum = _libelf_sum(checksum, (unsigned char *) d->d_buf, d->d_size); } /* * Return a 16-bit checksum compatible with Solaris. */ return (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL)); }