1 2de3b87aSKai Wang /*-
2 2de3b87aSKai Wang * Copyright (c) 2006,2008 Joseph Koshy
3 2de3b87aSKai Wang * All rights reserved.
4 2de3b87aSKai Wang *
5 2de3b87aSKai Wang * Redistribution and use in source and binary forms, with or without
6 2de3b87aSKai Wang * modification, are permitted provided that the following conditions
7 2de3b87aSKai Wang * are met:
8 2de3b87aSKai Wang * 1. Redistributions of source code must retain the above copyright
9 2de3b87aSKai Wang * notice, this list of conditions and the following disclaimer.
10 2de3b87aSKai Wang * 2. Redistributions in binary form must reproduce the above copyright
11 2de3b87aSKai Wang * notice, this list of conditions and the following disclaimer in the
12 2de3b87aSKai Wang * documentation and/or other materials provided with the distribution.
13 2de3b87aSKai Wang *
14 2de3b87aSKai Wang * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 2de3b87aSKai Wang * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 2de3b87aSKai Wang * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 2de3b87aSKai Wang * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 2de3b87aSKai Wang * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 2de3b87aSKai Wang * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 2de3b87aSKai Wang * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 2de3b87aSKai Wang * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 2de3b87aSKai Wang * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 2de3b87aSKai Wang * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 2de3b87aSKai Wang * SUCH DAMAGE.
25 2de3b87aSKai Wang */
26 2de3b87aSKai Wang
27 2de3b87aSKai Wang #include <ar.h>
28 2de3b87aSKai Wang #include <assert.h>
29 2de3b87aSKai Wang #include <libelf.h>
30 2de3b87aSKai Wang
31 2de3b87aSKai Wang #include "_libelf.h"
32 2de3b87aSKai Wang
33 *d003e0d7SEd Maste ELFTC_VCSID("$Id: elf_next.c 3710 2019-03-12 09:42:35Z jkoshy $");
34 2de3b87aSKai Wang
35 2de3b87aSKai Wang Elf_Cmd
elf_next(Elf * e)36 2de3b87aSKai Wang elf_next(Elf *e)
37 2de3b87aSKai Wang {
38 2de3b87aSKai Wang off_t next;
39 2de3b87aSKai Wang Elf *parent;
40 2de3b87aSKai Wang
41 2de3b87aSKai Wang if (e == NULL)
42 2de3b87aSKai Wang return (ELF_C_NULL);
43 2de3b87aSKai Wang
44 2de3b87aSKai Wang if ((parent = e->e_parent) == NULL) {
45 2de3b87aSKai Wang LIBELF_SET_ERROR(ARGUMENT, 0);
46 2de3b87aSKai Wang return (ELF_C_NULL);
47 2de3b87aSKai Wang }
48 2de3b87aSKai Wang
49 2de3b87aSKai Wang assert(parent->e_kind == ELF_K_AR);
50 2de3b87aSKai Wang assert(parent->e_cmd == ELF_C_READ);
51 2de3b87aSKai Wang assert(e->e_rawfile > parent->e_rawfile);
52 2de3b87aSKai Wang
53 cf781b2eSEd Maste next = e->e_rawfile - parent->e_rawfile + (off_t) e->e_rawsize;
54 2de3b87aSKai Wang next = (next + 1) & ~1; /* round up to an even boundary */
55 2de3b87aSKai Wang
56 cf781b2eSEd Maste /*
57 cf781b2eSEd Maste * Setup the 'e_next' field of the archive descriptor for the
58 cf781b2eSEd Maste * next call to 'elf_begin()'.
59 cf781b2eSEd Maste */
60 2de3b87aSKai Wang parent->e_u.e_ar.e_next = (next >= (off_t) parent->e_rawsize) ?
61 2de3b87aSKai Wang (off_t) 0 : next;
62 2de3b87aSKai Wang
63 *d003e0d7SEd Maste /*
64 *d003e0d7SEd Maste * Return an error if the 'e_next' field falls outside the current
65 *d003e0d7SEd Maste * file.
66 *d003e0d7SEd Maste *
67 *d003e0d7SEd Maste * This check is performed after updating the parent descriptor's
68 *d003e0d7SEd Maste * 'e_next' field so that the next call to elf_begin(3) will terminate
69 *d003e0d7SEd Maste * traversal of a too-small archive even if client code forgets to
70 *d003e0d7SEd Maste * check the return value from elf_next(3).
71 *d003e0d7SEd Maste */
72 *d003e0d7SEd Maste if (next > (off_t) parent->e_rawsize) {
73 *d003e0d7SEd Maste LIBELF_SET_ERROR(ARGUMENT, 0);
74 *d003e0d7SEd Maste return (ELF_C_NULL);
75 *d003e0d7SEd Maste }
76 *d003e0d7SEd Maste
77 2de3b87aSKai Wang return (ELF_C_READ);
78 2de3b87aSKai Wang }
79