1/*	$NetBSD: libelf_xlate.c,v 1.4 2010/02/22 10:48:33 darran Exp $	*/
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#if HAVE_NBTOOL_CONFIG_H
30# include "nbtool_config.h"
31#endif
32
33#include <sys/cdefs.h>
34/* __FBSDID("$FreeBSD: src/lib/libelf/libelf_xlate.c,v 1.3.2.1.2.1 2009/10/25 01:10:29 kensmith Exp $"); */
35
36#include <assert.h>
37#include <libelf.h>
38
39#include "_libelf.h"
40
41/*
42 * Translate to/from the file representation of ELF objects.
43 *
44 * Translation could potentially involve the following
45 * transformations:
46 *
47 * - an endianness conversion,
48 * - a change of layout, as the file representation of ELF objects
49 *   can differ from their in-memory representation.
50 * - a change in representation due to a layout version change.
51 */
52
53Elf_Data *
54_libelf_xlate(Elf_Data *dst, const Elf_Data *src, unsigned int encoding,
55    int elfclass, int direction)
56{
57	size_t cnt, dsz, fsz, msz;
58	uintptr_t sb, se, db, de;
59
60	if (encoding == ELFDATANONE)
61		encoding = _libelf_host_byteorder();
62
63	if ((encoding != ELFDATA2LSB && encoding != ELFDATA2MSB) ||
64	    dst == NULL || src == NULL || dst == src)	{
65		LIBELF_SET_ERROR(ARGUMENT, 0);
66		return (NULL);
67	}
68
69	assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
70	assert(direction == ELF_TOFILE || direction == ELF_TOMEMORY);
71
72	if (dst->d_version != src->d_version) {
73		LIBELF_SET_ERROR(UNIMPL, 0);
74		return (NULL);
75	}
76
77	if  (src->d_buf == NULL || dst->d_buf == NULL) {
78		LIBELF_SET_ERROR(DATA, 0);
79		return (NULL);
80	}
81
82	if ((int) src->d_type < 0 || src->d_type >= ELF_T_NUM) {
83		LIBELF_SET_ERROR(DATA, 0);
84		return (NULL);
85	}
86
87	if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
88	    (src->d_type, (size_t) 1, src->d_version)) == 0)
89		return (NULL);
90
91	msz = _libelf_msize(src->d_type, elfclass, src->d_version);
92
93	assert(msz > 0);
94
95	if (src->d_size % (direction == ELF_TOMEMORY ? fsz : msz)) {
96		LIBELF_SET_ERROR(DATA, 0);
97		return (NULL);
98	}
99
100	/*
101	 * Determine the number of objects that need to be converted, and
102	 * the space required for the converted objects in the destination
103	 * buffer.
104	 */
105	if (direction == ELF_TOMEMORY) {
106		cnt = src->d_size / fsz;
107		dsz = cnt * msz;
108	} else {
109		cnt = src->d_size / msz;
110		dsz = cnt * fsz;
111	}
112
113	if (dst->d_size  <  dsz) {
114		LIBELF_SET_ERROR(DATA, 0);
115		return (NULL);
116	}
117
118	sb = (uintptr_t) src->d_buf;
119	se = sb + src->d_size;
120	db = (uintptr_t) dst->d_buf;
121	de = db + dst->d_size;
122
123	/*
124	 * Check for overlapping buffers.  Note that db == sb is
125	 * allowed.
126	 */
127	if (db != sb && de > sb && se > db) {
128		LIBELF_SET_ERROR(DATA, 0);
129		return (NULL);
130	}
131
132	if ((direction == ELF_TOMEMORY ? db : sb) %
133	    _libelf_malign(src->d_type, elfclass)) {
134		LIBELF_SET_ERROR(DATA, 0);
135		return (NULL);
136	}
137
138	dst->d_type = src->d_type;
139	dst->d_size = dsz;
140
141	if (src->d_size == 0 ||
142	    (db == sb && encoding == _libelf_host_byteorder() && fsz == msz))
143		return (dst);	/* nothing more to do */
144
145	(_libelf_get_translator(src->d_type, direction, elfclass))(dst->d_buf,
146	    src->d_buf, cnt, encoding != _libelf_host_byteorder());
147
148	return (dst);
149}
150