1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright 2012 Nexenta Systems, Inc. All rights reserved.
24 */
25
26#include <stdio.h>
27#include <errno.h>
28#include <assert.h>
29#include <unistd.h>
30#include <libintl.h>
31#include <sys/multiboot.h>
32#include <sys/sysmacros.h>
33
34#include "bblk_einfo.h"
35#include "boot_utils.h"
36#include "mboot_extra.h"
37
38/*
39 * Common functions to deal with the fake-multiboot encapsulation of the
40 * bootblock and the location of the extra information area.
41 */
42
43/* mboot checksum routine. */
44uint32_t
45compute_checksum(char *data, uint32_t size)
46{
47	uint32_t	*ck_ptr;
48	uint32_t	cksum = 0;
49	int		i;
50
51	ck_ptr = (uint32_t *)data;
52	for (i = 0; i < size; i += sizeof (uint32_t))
53		cksum += *ck_ptr++;
54
55	return (-cksum);
56}
57
58/* Given a buffer, look for a multiboot header within it. */
59int
60find_multiboot(char *buffer, uint32_t buf_size, uint32_t *mboot_off)
61{
62	multiboot_header_t	*mboot;
63	uint32_t		*iter;
64	uint32_t		cksum;
65	uint32_t		boundary;
66	int			i = 0;
67
68	iter = (uint32_t *)buffer;
69	*mboot_off = 0;
70	/* multiboot header has to be within the first 32K. */
71	boundary = MBOOT_SCAN_SIZE;
72	if (boundary > buf_size)
73		boundary = buf_size;
74
75	boundary = boundary - sizeof (multiboot_header_t);
76
77	for (i = 0; i < boundary; i += 4, iter++) {
78
79		mboot = (multiboot_header_t *)iter;
80		if (mboot->magic != MB_HEADER_MAGIC)
81			continue;
82
83		/* Found magic signature -- check checksum. */
84		cksum = -(mboot->flags + mboot->magic);
85		if (mboot->checksum != cksum) {
86			BOOT_DEBUG("multiboot magic found at %p, but checksum "
87			    "mismatches (is %x, should be %x)\n", mboot,
88			    mboot->checksum, cksum);
89			continue;
90		} else {
91			if (!(mboot->flags & BB_MBOOT_AOUT_FLAG)) {
92				BOOT_DEBUG("multiboot structure found, but no "
93				    "AOUT kludge specified, skipping.\n");
94				continue;
95			} else {
96				/* proper multiboot structure found. */
97				*mboot_off = i;
98				return (BC_SUCCESS);
99			}
100		}
101	}
102
103	return (BC_ERROR);
104}
105
106/*
107 * Given a pointer to the extra information area (a sequence of bb_header_ext_t
108 * + payload chunks), find the extended information structure.
109 */
110bblk_einfo_t *
111find_einfo(char *extra, uint32_t size)
112{
113	bb_header_ext_t		*ext_header;
114	bblk_einfo_t		*einfo;
115	uint32_t		cksum;
116
117	assert(extra != NULL);
118
119	ext_header = (bb_header_ext_t *)extra;
120	if (ext_header->size > size) {
121		BOOT_DEBUG("Unable to find extended versioning information, "
122		    "data size too big\n");
123		return (NULL);
124	}
125
126	cksum = compute_checksum(extra + sizeof (bb_header_ext_t),
127	    ext_header->size);
128	BOOT_DEBUG("Extended information header checksum is %x\n", cksum);
129
130	if (cksum != ext_header->checksum) {
131		BOOT_DEBUG("Unable to find extended versioning information, "
132		    "data looks corrupted\n");
133		return (NULL);
134	}
135
136	/*
137	 * Currently we only have one extra header so it must be encapsulating
138	 * the extended information structure.
139	 */
140	einfo = (bblk_einfo_t *)(extra + sizeof (bb_header_ext_t));
141	if (memcmp(einfo->magic, EINFO_MAGIC, EINFO_MAGIC_SIZE) != 0) {
142		BOOT_DEBUG("Unable to read stage2 extended versioning "
143		    "information, wrong magic identifier\n");
144		BOOT_DEBUG("Found %s, expected %s\n", einfo->magic,
145		    EINFO_MAGIC);
146		return (NULL);
147	}
148
149	return (einfo);
150}
151
152/*
153 * Given a pointer to the extra area, add the extended information structure
154 * encapsulated by a bb_header_ext_t structure.
155 */
156void
157add_einfo(char *extra, char *updt_str, bblk_hs_t *hs, uint32_t avail_space)
158{
159	bb_header_ext_t	*ext_hdr;
160	uint32_t	used_space;
161	unsigned char	*dest;
162	int		ret;
163
164	assert(extra != NULL);
165
166	if (updt_str == NULL) {
167		BOOT_DEBUG("WARNING: no update string passed to "
168		    "add_stage2_einfo()\n");
169		return;
170	}
171
172	/* Reserve space for the extra header. */
173	ext_hdr = (bb_header_ext_t *)extra;
174	dest = (unsigned char *)extra + sizeof (*ext_hdr);
175	/* Place the extended information structure. */
176	ret = prepare_and_write_einfo(dest, updt_str, hs, avail_space,
177	    &used_space);
178	if (ret != 0) {
179		(void) fprintf(stderr, gettext("Unable to write the extended "
180		    "versioning information\n"));
181		return;
182	}
183
184	/* Fill the extended information associated header. */
185	ext_hdr->size = P2ROUNDUP(used_space, 8);
186	ext_hdr->checksum = compute_checksum((char *)dest, ext_hdr->size);
187}
188