elf_next.c revision 276371 
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 <sys/cdefs.h>
28
29#include <ar.h>
30#include <assert.h>
31#include <libelf.h>
32
33#include "_libelf.h"
34
35ELFTC_VCSID("$Id: elf_next.c 2989 2014-03-17 09:56:46Z jkoshy $");
36
37Elf_Cmd
38elf_next(Elf *e)
39{
40	off_t next;
41	Elf *parent;
42
43	if (e == NULL)
44		return (ELF_C_NULL);
45
46	 if ((parent = e->e_parent) == NULL) {
47		 LIBELF_SET_ERROR(ARGUMENT, 0);
48		 return (ELF_C_NULL);
49	 }
50
51	assert(parent->e_kind == ELF_K_AR);
52	assert(parent->e_cmd == ELF_C_READ);
53	assert(e->e_rawfile > parent->e_rawfile);
54
55	next = e->e_rawfile - parent->e_rawfile + (off_t) e->e_rawsize;
56	next = (next + 1) & ~1;	/* round up to an even boundary */
57
58	/*
59	 * Setup the 'e_next' field of the archive descriptor for the
60	 * next call to 'elf_begin()'.
61	 */
62	parent->e_u.e_ar.e_next = (next >= (off_t) parent->e_rawsize) ?
63	    (off_t) 0 : next;
64
65	return (ELF_C_READ);
66}
67