1/*	$OpenBSD: landisk_installboot.c,v 1.12 2022/12/28 21:30:16 jmc Exp $	*/
2
3/*
4 * Copyright (c) 2013 Joel Sing <jsing@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19#include <sys/param.h>	/* DEV_BSIZE */
20#include <sys/disklabel.h>
21#include <sys/dkio.h>
22#include <sys/ioctl.h>
23#include <sys/stat.h>
24
25#include <ufs/ffs/fs.h>
26
27#include <err.h>
28#include <fcntl.h>
29#include <stdio.h>
30#include <stdlib.h>
31#include <string.h>
32#include <unistd.h>
33
34#include "installboot.h"
35
36void	md_bootstrap(int, char *, char *);
37
38char	*bootldr;
39
40void
41md_init(void)
42{
43	stages = 2;
44	stage1 = "/usr/mdec/xxboot";
45	stage2 = "/usr/mdec/boot";
46
47	bootldr = "/boot";
48}
49
50void
51md_loadboot(void)
52{
53}
54
55void
56md_prepareboot(int devfd, char *dev)
57{
58}
59
60void
61md_installboot(int devfd, char *dev)
62{
63	/* XXX - is this necessary? */
64	sync();
65
66	bootldr = fileprefix(root, bootldr);
67	if (bootldr == NULL)
68		exit(1);
69	if (!nowrite)
70		if (filecopy(stage2, bootldr) == -1)
71			exit(1);
72
73	/*
74	 * Write bootblock into the beginning of the OpenBSD partition or
75	 * at the beginning of the disk.
76	 */
77	md_bootstrap(devfd, dev, stage1);
78}
79
80void
81md_bootstrap(int devfd, char *dev, char *bootfile)
82{
83	struct disklabel dl;
84	struct disklabel *lp;
85	struct partition *pp;
86	char *boot, *p, part;
87	size_t bootsize;
88	size_t bootsec;
89	struct stat sb;
90	daddr_t bootpos = 0;
91	int fd, i;
92
93	/*
94	 * Install bootstrap code onto the given disk, preserving the
95	 * existing disklabel.
96	 */
97
98	/* Read disklabel from disk. */
99	if (ioctl(devfd, DIOCGDINFO, &dl) == -1)
100		err(1, "disklabel");
101	if (dl.d_secsize == 0) {
102		warnx("disklabel has sector size of 0, assuming %d", DEV_BSIZE);
103		dl.d_secsize = DEV_BSIZE;
104	}
105
106	/* Read bootstrap file. */
107	if (verbose)
108		fprintf(stderr, "reading bootstrap from %s\n", bootfile);
109	fd = open(bootfile, O_RDONLY);
110	if (fd == -1)
111		err(1, "open %s", bootfile);
112	if (fstat(fd, &sb) == -1)
113		err(1, "fstat %s", bootfile);
114	bootsec = howmany((ssize_t)sb.st_size, dl.d_secsize);
115	bootsize = bootsec * dl.d_secsize;
116	if (verbose)
117		fprintf(stderr, "bootstrap is %zu bytes "
118		    "(%zu sectors @ %u bytes = %zu bytes)\n",
119		    (ssize_t)sb.st_size, bootsec, dl.d_secsize, bootsize);
120	boot = calloc(1, bootsize);
121	if (boot == NULL)
122		err(1, "calloc");
123	if (read(fd, boot, bootsize) != (ssize_t)sb.st_size)
124		err(1, "read");
125	close(fd);
126
127	/*
128	 * The landisk bootstrap can work when put either at the start of the
129	 * disk, or at the start of an OpenBSD MBR partition, invoked from
130	 * /usr/mdec/mbr.
131	 * Check for a partition table in order to decide where to put the
132	 * first-level bootstrap code.
133	 */
134
135	if (dl.d_secsize >= sizeof(struct dos_mbr)) {
136		uint8_t *secbuf;
137		struct dos_mbr *mbr;
138
139		secbuf = malloc(dl.d_secsize);
140		if (secbuf == NULL)
141			err(1, "malloc");
142
143		/* Read MBR. */
144		if (pread(devfd, secbuf, dl.d_secsize, 0) != dl.d_secsize)
145			err(4, "can't read mbr");
146		mbr = (struct dos_mbr *)secbuf;
147		/* safe check because landisk is little endian */
148		if (mbr->dmbr_sign == DOSMBR_SIGNATURE) {
149			for (i = 0; i < NDOSPART; i++) {
150				if (mbr->dmbr_parts[i].dp_typ ==
151				    DOSPTYP_OPENBSD) {
152					bootpos = mbr->dmbr_parts[i].dp_start;
153					break;
154				}
155			}
156		}
157
158		free(secbuf);
159	}
160
161	if (bootpos == 0) {
162		/*
163		 * Installing at the start of the disk.
164		 * Check that the bootstrap will fit - partitions must not
165		 * overlap, or if they do, the partition type must be either
166		 * FS_BOOT or FS_UNUSED. The 'c' partition will always overlap
167		 * and is ignored.
168		 */
169		if (verbose)
170			fprintf(stderr,
171			    "ensuring used partitions do not overlap "
172			    "with bootstrap sectors 0-%zu\n", bootsec);
173		for (i = 0; i < dl.d_npartitions; i++) {
174			part = 'a' + i;
175			pp = &dl.d_partitions[i];
176			if (i == RAW_PART)
177				continue;
178			if (DL_GETPSIZE(pp) == 0)
179				continue;
180			if (bootpos + (u_int64_t)bootsec <= DL_GETPOFFSET(pp))
181				continue;
182			switch (pp->p_fstype) {
183			case FS_BOOT:
184				break;
185			case FS_UNUSED:
186				warnx("bootstrap overlaps "
187				    "with unused partition %c", part);
188				break;
189			default:
190				errx(1, "bootstrap overlaps with partition %c",
191				    part);
192			}
193		}
194	} else {
195		/*
196		 * Installing at the start of the OpenBSD partition.
197		 * We only need to ensure the bootstrap code fits in the
198		 * BBSIZE reserved area at the beginning of the file
199		 * system.
200		 */
201		if (bootsize > BBSIZE)
202			errx(1, "bootstrap is too large");
203	}
204
205	/*
206	 * Make sure the bootstrap has left space for the disklabel.
207	 * N.B.: LABELSECTOR *is* a DEV_BSIZE quantity!
208	 */
209	lp = (struct disklabel *)(boot + (LABELSECTOR * DEV_BSIZE) +
210	    LABELOFFSET);
211	for (i = 0, p = (char *)lp; i < (int)sizeof(*lp); i++)
212		if (p[i] != 0)
213			errx(1, "bootstrap has data in disklabel area");
214
215	/* Patch the disklabel into the bootstrap code. */
216	memcpy(lp, &dl, sizeof(dl));
217
218	/* Write the bootstrap out to the disk. */
219	bootpos *= dl.d_secsize;
220	if (verbose)
221		fprintf(stderr, "%s bootstrap to disk at offset %llx\n",
222		    (nowrite ? "would write" : "writing"), bootpos);
223	if (nowrite)
224		return;
225	if (pwrite(devfd, boot, bootsize, bootpos) != (ssize_t)bootsize)
226		err(1, "pwrite");
227}
228