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/*-
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <gelf.h>
#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));
}
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