xref: /freebsd/contrib/elftoolchain/libelf/elf_next.c (revision 93e779a26c651610ac6e7986d67ecc9ed2cadcbf)
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 <assert.h>
29 #include <libelf.h>
30 
31 #include "_libelf.h"
32 
33 ELFTC_VCSID("$Id: elf_next.c 3174 2015-03-27 17:13:41Z emaste $");
34 
35 Elf_Cmd
36 elf_next(Elf *e)
37 {
38 	off_t next;
39 	Elf *parent;
40 
41 	if (e == NULL)
42 		return (ELF_C_NULL);
43 
44 	 if ((parent = e->e_parent) == NULL) {
45 		 LIBELF_SET_ERROR(ARGUMENT, 0);
46 		 return (ELF_C_NULL);
47 	 }
48 
49 	assert(parent->e_kind == ELF_K_AR);
50 	assert(parent->e_cmd == ELF_C_READ);
51 	assert(e->e_rawfile > parent->e_rawfile);
52 
53 	next = e->e_rawfile - parent->e_rawfile + (off_t) e->e_rawsize;
54 	next = (next + 1) & ~1;	/* round up to an even boundary */
55 
56 	/*
57 	 * Setup the 'e_next' field of the archive descriptor for the
58 	 * next call to 'elf_begin()'.
59 	 */
60 	parent->e_u.e_ar.e_next = (next >= (off_t) parent->e_rawsize) ?
61 	    (off_t) 0 : next;
62 
63 	return (ELF_C_READ);
64 }
65