1/*	$NetBSD: compat.c,v 1.1 2018/10/17 23:36:58 joerg Exp $	*/
2/*-
3 * Copyright (c) 2018 The NetBSD Foundation, Inc.
4 * All rights reserved.
5 *
6 * This code is derived from software contributed to The NetBSD Foundation
7 * by Joerg Sonnenberger.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31/*
32 * Early ELF support in NetBSD up to April 2nd, 2000 exposed dlopen and
33 * friends via function pointers in the main object that is passed to the
34 * startup code in crt0.o. Later versions kept the magic and version number
35 * checks, but depend on normal symbol interposition to get the symbols from
36 * rtld. The compatibility object build here contains just enough fields to
37 * make either routine happy without polluting the rest of rtld.
38 */
39
40#include <sys/cdefs.h>
41__RCSID("$NetBSD: compat.c,v 1.1 2018/10/17 23:36:58 joerg Exp $");
42
43#include "rtld.h"
44
45#if defined(__alpha__)
46#define RTLD_OBJ_DLOPEN_OFFSET 264
47#elif defined(__i386__)
48#define RTLD_OBJ_DLOPEN_OFFSET 140
49#elif defined(__mips) && defined(_ABIO32)
50/* The MIPS legacy support is required for O32 only, N32 is not affected. */
51#define RTLD_OBJ_DLOPEN_OFFSET 152
52#elif defined(__powerpc__) && !defined(__powerpc64__)
53/* Only 32bit PowerPC is affected. */
54#define RTLD_OBJ_DLOPEN_OFFSET 140
55#elif defined(__sparc) && !defined(__sparc64__)
56/* Only 32bit SPARC is affected, 64bit SPARC ELF support was incomplete. */
57#define RTLD_OBJ_DLOPEN_OFFSET 140
58#endif
59
60#define RTLD_MAGIC	0xd550b87a
61#define RTLD_VERSION	1
62
63#ifdef RTLD_OBJ_DLOPEN_OFFSET
64const uintptr_t _rtld_compat_obj[] = {
65#  ifdef _LP64
66#    if BYTE_ORDER == BIG_ENDIAN
67	[0] = (((uint64_t)RTLD_MAGIC) << 32) | RTLD_VERSION,
68#    else
69	[0] = (((uint64_t)RTLD_VERSION) << 32) | RTLD_MAGIC,
70#    endif
71#  else
72	[0] = RTLD_MAGIC,
73	[1] = RTLD_VERSION,
74#  endif
75	[(RTLD_OBJ_DLOPEN_OFFSET / sizeof(uintptr_t)) + 0] = (uintptr_t)dlopen,
76	[(RTLD_OBJ_DLOPEN_OFFSET / sizeof(uintptr_t)) + 1] = (uintptr_t)dlsym,
77	[(RTLD_OBJ_DLOPEN_OFFSET / sizeof(uintptr_t)) + 2] = (uintptr_t)dlerror,
78	[(RTLD_OBJ_DLOPEN_OFFSET / sizeof(uintptr_t)) + 3] = (uintptr_t)dlclose,
79	[(RTLD_OBJ_DLOPEN_OFFSET / sizeof(uintptr_t)) + 4] = (uintptr_t)dladdr,
80};
81#else
82const uintptr_t _rtld_compat_obj[] = {
83#  ifdef _LP64
84#    if BYTE_ORDER == BIG_ENDIAN
85	[0] = (((uint64_t)RTLD_MAGIC) << 32) | RTLD_VERSION,
86#    else
87	[0] = (((uint64_t)RTLD_VERSION) << 32) | RTLD_MAGIC,
88#    endif
89#  else
90	[0] = RTLD_MAGIC,
91	[1] = RTLD_VERSION,
92#  endif
93};
94#endif /* RTLD_OBJ_DLOPEN_OFFSET */
95