libelf_checksum.c revision 260697
1254721Semaste/*- 2254721Semaste * Copyright (c) 2006,2008 Joseph Koshy 3254721Semaste * All rights reserved. 4254721Semaste * 5254721Semaste * Redistribution and use in source and binary forms, with or without 6254721Semaste * modification, are permitted provided that the following conditions 7254721Semaste * are met: 8254721Semaste * 1. Redistributions of source code must retain the above copyright 9254721Semaste * notice, this list of conditions and the following disclaimer. 10254721Semaste * 2. Redistributions in binary form must reproduce the above copyright 11254721Semaste * notice, this list of conditions and the following disclaimer in the 12254721Semaste * documentation and/or other materials provided with the distribution. 13254721Semaste * 14254721Semaste * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15254721Semaste * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16254721Semaste * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17254721Semaste * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18254721Semaste * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19254721Semaste * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20254721Semaste * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21254721Semaste * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22254721Semaste * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23254721Semaste * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24254721Semaste * SUCH DAMAGE. 25254721Semaste */ 26254721Semaste 27254721Semaste#include <sys/cdefs.h> 28254721Semaste 29254721Semaste#include <gelf.h> 30254721Semaste 31254721Semaste#include "_libelf.h" 32254721Semaste 33254721SemasteELFTC_VCSID("$Id: libelf_checksum.c 2225 2011-11-26 18:55:54Z jkoshy $"); 34254721Semaste 35254721Semastestatic unsigned long 36254721Semaste_libelf_sum(unsigned long c, const unsigned char *s, size_t size) 37254721Semaste{ 38254721Semaste if (s == NULL || size == 0) 39254721Semaste return (c); 40254721Semaste 41254721Semaste while (size--) 42254721Semaste c += *s++; 43254721Semaste 44254721Semaste return (c); 45254721Semaste} 46254721Semaste 47254721Semasteunsigned long 48254721Semaste_libelf_checksum(Elf *e, int elfclass) 49254721Semaste{ 50254721Semaste size_t shn; 51254721Semaste Elf_Scn *scn; 52254721Semaste Elf_Data *d; 53254721Semaste unsigned long checksum; 54254721Semaste GElf_Ehdr eh; 55254721Semaste GElf_Shdr shdr; 56254721Semaste 57254721Semaste if (e == NULL) { 58254721Semaste LIBELF_SET_ERROR(ARGUMENT, 0); 59254721Semaste return (0L); 60254721Semaste } 61254721Semaste 62254721Semaste if (e->e_class != elfclass) { 63254721Semaste LIBELF_SET_ERROR(CLASS, 0); 64254721Semaste return (0L); 65254721Semaste } 66254721Semaste 67254721Semaste if (gelf_getehdr(e, &eh) == NULL) 68254721Semaste return (0); 69254721Semaste 70254721Semaste /* 71254721Semaste * Iterate over all sections in the ELF file, computing the 72254721Semaste * checksum along the way. 73254721Semaste * 74254721Semaste * The first section is always SHN_UNDEF and can be skipped. 75254721Semaste * Non-allocatable sections are skipped, as are sections that 76254721Semaste * could be affected by utilities such as strip(1). 77254721Semaste */ 78254721Semaste 79254721Semaste checksum = 0; 80254721Semaste for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) { 81254721Semaste if ((scn = elf_getscn(e, shn)) == NULL) 82254721Semaste return (0); 83254721Semaste if (gelf_getshdr(scn, &shdr) == NULL) 84254721Semaste return (0); 85254721Semaste if ((shdr.sh_flags & SHF_ALLOC) == 0 || 86254721Semaste shdr.sh_type == SHT_DYNAMIC || 87254721Semaste shdr.sh_type == SHT_DYNSYM) 88254721Semaste continue; 89254721Semaste 90254721Semaste d = NULL; 91254721Semaste while ((d = elf_rawdata(scn, d)) != NULL) 92254721Semaste checksum = _libelf_sum(checksum, 93254721Semaste (unsigned char *) d->d_buf, d->d_size); 94254721Semaste } 95254721Semaste 96254721Semaste /* 97254721Semaste * Return a 16-bit checksum compatible with Solaris. 98254721Semaste */ 99254721Semaste return (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL)); 100254721Semaste} 101254721Semaste