12de3b87aSKai Wang /*-
22de3b87aSKai Wang * Copyright (c) 2006,2008 Joseph Koshy
32de3b87aSKai Wang * All rights reserved.
42de3b87aSKai Wang *
52de3b87aSKai Wang * Redistribution and use in source and binary forms, with or without
62de3b87aSKai Wang * modification, are permitted provided that the following conditions
72de3b87aSKai Wang * are met:
82de3b87aSKai Wang * 1. Redistributions of source code must retain the above copyright
92de3b87aSKai Wang * notice, this list of conditions and the following disclaimer.
102de3b87aSKai Wang * 2. Redistributions in binary form must reproduce the above copyright
112de3b87aSKai Wang * notice, this list of conditions and the following disclaimer in the
122de3b87aSKai Wang * documentation and/or other materials provided with the distribution.
132de3b87aSKai Wang *
142de3b87aSKai Wang * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
152de3b87aSKai Wang * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
162de3b87aSKai Wang * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
172de3b87aSKai Wang * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
182de3b87aSKai Wang * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
192de3b87aSKai Wang * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
202de3b87aSKai Wang * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
212de3b87aSKai Wang * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
222de3b87aSKai Wang * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
232de3b87aSKai Wang * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
242de3b87aSKai Wang * SUCH DAMAGE.
252de3b87aSKai Wang */
262de3b87aSKai Wang
272de3b87aSKai Wang #include <ar.h>
282de3b87aSKai Wang #include <libelf.h>
292de3b87aSKai Wang
302de3b87aSKai Wang #include "_libelf.h"
312de3b87aSKai Wang
32*d003e0d7SEd Maste ELFTC_VCSID("$Id: elf_rand.c 3716 2019-03-18 22:01:01Z jkoshy $");
332de3b87aSKai Wang
342de3b87aSKai Wang off_t
elf_rand(Elf * ar,off_t offset)352de3b87aSKai Wang elf_rand(Elf *ar, off_t offset)
362de3b87aSKai Wang {
372de3b87aSKai Wang struct ar_hdr *arh;
38*d003e0d7SEd Maste off_t offset_of_member;
392de3b87aSKai Wang
402de3b87aSKai Wang if (ar == NULL || ar->e_kind != ELF_K_AR ||
412de3b87aSKai Wang (offset & 1) || offset < SARMAG ||
42*d003e0d7SEd Maste offset >= ar->e_rawsize) {
43*d003e0d7SEd Maste LIBELF_SET_ERROR(ARGUMENT, 0);
44*d003e0d7SEd Maste return 0;
45*d003e0d7SEd Maste }
46*d003e0d7SEd Maste
47*d003e0d7SEd Maste offset_of_member = offset + (off_t) sizeof(struct ar_hdr);
48*d003e0d7SEd Maste
49*d003e0d7SEd Maste if (offset_of_member <= 0 || /* Numeric overflow. */
50*d003e0d7SEd Maste offset_of_member >= ar->e_rawsize) {
512de3b87aSKai Wang LIBELF_SET_ERROR(ARGUMENT, 0);
522de3b87aSKai Wang return 0;
532de3b87aSKai Wang }
542de3b87aSKai Wang
552de3b87aSKai Wang arh = (struct ar_hdr *) (ar->e_rawfile + offset);
562de3b87aSKai Wang
572de3b87aSKai Wang /* a too simple sanity check */
582de3b87aSKai Wang if (arh->ar_fmag[0] != '`' || arh->ar_fmag[1] != '\n') {
592de3b87aSKai Wang LIBELF_SET_ERROR(ARCHIVE, 0);
602de3b87aSKai Wang return 0;
612de3b87aSKai Wang }
622de3b87aSKai Wang
632de3b87aSKai Wang ar->e_u.e_ar.e_next = offset;
642de3b87aSKai Wang
652de3b87aSKai Wang return (offset);
662de3b87aSKai Wang }
67