elf_rand.c revision 302408 
1/*-
2 * Copyright (c) 2006,2008 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <ar.h>
28#include <libelf.h>
29
30#include "_libelf.h"
31
32ELFTC_VCSID("$Id: elf_rand.c 3174 2015-03-27 17:13:41Z emaste $");
33
34off_t
35elf_rand(Elf *ar, off_t offset)
36{
37	struct ar_hdr *arh;
38
39	if (ar == NULL || ar->e_kind != ELF_K_AR ||
40	    (offset & 1) || offset < SARMAG ||
41	    (size_t) offset + sizeof(struct ar_hdr) >= ar->e_rawsize) {
42		LIBELF_SET_ERROR(ARGUMENT, 0);
43		return 0;
44	}
45
46	arh = (struct ar_hdr *) (ar->e_rawfile + offset);
47
48	/* a too simple sanity check */
49	if (arh->ar_fmag[0] != '`' || arh->ar_fmag[1] != '\n') {
50		LIBELF_SET_ERROR(ARCHIVE, 0);
51		return 0;
52	}
53
54	ar->e_u.e_ar.e_next = offset;
55
56	return (offset);
57}
58