external/bsd/libelf/dist/elf_rand.c

   1 /*      $NetBSD$        */
   2
   3 /*-
   4  * Copyright (c) 2006 Joseph Koshy
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 /* __FBSDID("$FreeBSD: src/lib/libelf/elf_rand.c,v 1.1.10.1.2.1 2009/10/25 01:10:29 kensmith Exp $"); */
  31
  32 #include <ar.h>
  33 #include <libelf.h>
  34
  35 #include "_libelf.h"
  36
  37 off_t
  38 elf_rand(Elf *ar, off_t offset)
  39 {
  40         struct ar_hdr *arh;
  41
  42         if (ar == NULL || ar->e_kind != ELF_K_AR ||
  43             (offset & 1) || offset < SARMAG ||
  44             offset + sizeof(struct ar_hdr) >= ar->e_rawsize) {
  45                 LIBELF_SET_ERROR(ARGUMENT, 0);
  46                 return 0;
  47         }
  48
  49         arh = (struct ar_hdr *) (ar->e_rawfile + offset);
  50
  51         /* a too simple sanity check */
  52         if (arh->ar_fmag[0] != '`' || arh->ar_fmag[1] != '\n') {
  53                 LIBELF_SET_ERROR(ARCHIVE, 0);
  54                 return 0;
  55         }
  56
  57         ar->e_u.e_ar.e_next = offset;
  58
  59         return (offset);
  60 }