1 /* $NetBSD: biosboot.c,v 1.34 2025/02/23 20:47:19 christos Exp $ */
2
3 /*
4 * Copyright (c) 2009 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to the NetBSD Foundation
8 * by Mike M. Volokhov. Development of this software was supported by the
9 * Google Summer of Code program.
10 * The GSoC project was mentored by Allen Briggs and Joerg Sonnenberger.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 #if HAVE_NBTOOL_CONFIG_H
35 #include "nbtool_config.h"
36 #endif
37
38 #include <sys/cdefs.h>
39 #ifdef __RCSID
40 __RCSID("$NetBSD: biosboot.c,v 1.34 2025/02/23 20:47:19 christos Exp $");
41 #endif
42
43 #include <sys/stat.h>
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
46 #include <sys/param.h>
47 #include <sys/bootblock.h>
48
49 #if defined(DIOCGWEDGEINFO) && !defined(HAVE_NBTOOL_CONFIG_H)
50 #define USE_WEDGES
51 #endif
52 #ifdef USE_WEDGES
53 #include <sys/disk.h>
54 #endif
55
56 #include <err.h>
57 #include <fcntl.h>
58 #include <paths.h>
59 #include <stddef.h>
60 #include <stdio.h>
61 #include <stdlib.h>
62 #include <string.h>
63 #include <unistd.h>
64
65 #include "map.h"
66 #include "gpt.h"
67 #include "gpt_private.h"
68
69 #define DEFAULT_BOOTDIR "/usr/mdec"
70 #define DEFAULT_BOOTCODE "gptmbr.bin"
71
72 static int cmd_biosboot(gpt_t, int, char *[]);
73
74 static const char *biosboothelp[] = {
75 "[-A] [-c bootcode] [-i index] [-L label] [-b startsec]",
76 #if notyet
77 "[-a alignment] [-b blocknr] [-i index] [-l label]",
78 "[-s size] [-t type]",
79 #endif
80 };
81
82 const struct gpt_cmd c_biosboot = {
83 "biosboot",
84 cmd_biosboot,
85 biosboothelp, __arraycount(biosboothelp),
86 0,
87 };
88
89 #define usage() gpt_usage(NULL, &c_biosboot)
90
91 static struct mbr*
read_boot(gpt_t gpt,const char * bootpath)92 read_boot(gpt_t gpt, const char *bootpath)
93 {
94 int bfd, ret = -1;
95 struct mbr *buf;
96 struct stat st;
97 char *bp;
98
99 buf = NULL;
100 bfd = -1;
101
102 if (bootpath == NULL)
103 bp = strdup(DEFAULT_BOOTDIR "/" DEFAULT_BOOTCODE);
104 else if (*bootpath == '/')
105 bp = strdup(bootpath);
106 else {
107 if (asprintf(&bp, "%s/%s", DEFAULT_BOOTDIR, bootpath) < 0)
108 bp = NULL;
109 }
110
111 if (bp == NULL) {
112 gpt_warn(gpt, "Can't allocate memory for bootpath");
113 goto fail;
114 }
115
116 if ((buf = malloc((size_t)gpt->secsz)) == NULL) {
117 gpt_warn(gpt, "Can't allocate memory for sector");
118 goto fail;
119 }
120
121
122 if ((bfd = open(bp, O_RDONLY)) < 0 || fstat(bfd, &st) == -1) {
123 gpt_warn(gpt, "Can't open `%s'", bp);
124 goto fail;
125 }
126
127 if (st.st_size != MBR_DSN_OFFSET) {
128 gpt_warnx(gpt, "The bootcode in `%s' does not match the"
129 " expected size %u", bp, MBR_DSN_OFFSET);
130 goto fail;
131 }
132
133 if (read(bfd, buf, (size_t)st.st_size) != (ssize_t)st.st_size) {
134 gpt_warn(gpt, "Error reading from `%s'", bp);
135 goto fail;
136 }
137
138 ret = 0;
139 fail:
140 if (bfd != -1)
141 close(bfd);
142 if (ret == -1) {
143 free(buf);
144 buf = NULL;
145 }
146 free(bp);
147 return buf;
148 }
149
150 static int
set_bootable(gpt_t gpt,map_t map,map_t tbl,unsigned int i)151 set_bootable(gpt_t gpt, map_t map, map_t tbl, unsigned int i)
152 {
153 unsigned int j;
154 struct gpt_hdr *hdr = map->map_data;
155 struct gpt_ent *ent;
156 unsigned int ne = le32toh(hdr->hdr_entries);
157
158 for (j = 0; j < ne; j++) {
159 ent = gpt_ent(map, tbl, j);
160 ent->ent_attr &= ~GPT_ENT_ATTR_LEGACY_BIOS_BOOTABLE;
161 }
162
163 ent = gpt_ent(map, tbl, i);
164 ent->ent_attr |= GPT_ENT_ATTR_LEGACY_BIOS_BOOTABLE;
165
166 return gpt_write_crc(gpt, map, tbl);
167 }
168
169 static int
biosboot(gpt_t gpt,off_t start,uint64_t size,u_int entry,uint8_t * label,const char * bootpath,int active)170 biosboot(gpt_t gpt, off_t start, uint64_t size, u_int entry, uint8_t *label,
171 const char *bootpath, int active)
172 {
173 map_t mbrmap, m;
174 struct mbr *mbr, *bootcode;
175 unsigned int i;
176 struct gpt_ent *ent;
177 uint8_t utfbuf[__arraycount(ent->ent_name) * 3 + 1];
178
179 /*
180 * Parse and validate partition maps
181 */
182 if (gpt_hdr(gpt) == NULL)
183 return -1;
184
185 mbrmap = map_find(gpt, MAP_TYPE_PMBR);
186 if (mbrmap == NULL || mbrmap->map_start != 0) {
187 gpt_warnx(gpt, "No valid Protective MBR found");
188 return -1;
189 }
190
191 mbr = mbrmap->map_data;
192
193 /*
194 * Update the boot code
195 */
196 if ((bootcode = read_boot(gpt, bootpath)) == NULL) {
197 gpt_warnx(gpt, "Error reading bootcode");
198 return -1;
199 }
200 (void)memcpy(&mbr->mbr_code, &bootcode->mbr_code,
201 sizeof(mbr->mbr_code));
202 free(bootcode);
203
204 for (i = 0; i < __arraycount(mbr->mbr_part); i++)
205 if (mbr->mbr_part[i].part_typ == MBR_PTYPE_PMBR)
206 mbr->mbr_part[i].part_flag = active ? 0x80 : 0;
207
208 /*
209 * Walk through the GPT and see where we can boot from
210 */
211 for (m = map_first(gpt); m != NULL; m = m->map_next) {
212 if (m->map_type != MAP_TYPE_GPT_PART || m->map_index < 1)
213 continue;
214
215 ent = m->map_data;
216
217 /* first, prefer user selection */
218 if (entry > 0 && m->map_index == entry)
219 break;
220
221 if (label != NULL) {
222 utf16_to_utf8(ent->ent_name,
223 __arraycount(ent->ent_name), utfbuf,
224 __arraycount(utfbuf));
225 if (strcmp((char *)label, (char *)utfbuf) == 0)
226 break;
227 }
228
229 /* next, partition as could be specified by wedge */
230 if (entry < 1 && label == NULL && size > 0 &&
231 m->map_start == start && m->map_size == (off_t)size)
232 break;
233 /* next could be start sector specified by -b option */
234 if (entry < 1 && label == NULL && size == 0 &&
235 m->map_start == start)
236 break;
237 }
238
239 if (m == NULL) {
240 gpt_warnx(gpt, "No bootable partition");
241 return -1;
242 }
243
244 i = m->map_index - 1;
245
246
247 if (set_bootable(gpt, gpt->gpt, gpt->tbl, i) == -1)
248 return -1;
249
250 if (set_bootable(gpt, gpt->tpg, gpt->lbt, i) == -1)
251 return -1;
252
253 if (gpt_write(gpt, mbrmap) == -1) {
254 gpt_warnx(gpt, "Cannot update Protective MBR");
255 return -1;
256 }
257
258 gpt_msg(gpt, "Partition %d marked as bootable", i + 1);
259 return 0;
260 }
261
262 static int
cmd_biosboot(gpt_t gpt,int argc,char * argv[])263 cmd_biosboot(gpt_t gpt, int argc, char *argv[])
264 {
265 #ifdef USE_WEDGES
266 struct dkwedge_info dkw;
267 #endif
268 int ch;
269 gpt_t ngpt = gpt;
270 off_t start = 0;
271 uint64_t size = 0;
272 int active = 0;
273 unsigned int entry = 0;
274 uint8_t *label = NULL;
275 char *bootpath = NULL;
276
277 while ((ch = getopt(argc, argv, "Ac:i:L:b:")) != -1) {
278 switch(ch) {
279 case 'A':
280 active = 1;
281 break;
282 case 'c':
283 if (gpt_name_get(gpt, &bootpath) == -1)
284 goto usage;
285 break;
286 case 'i':
287 if (gpt_uint_get(gpt, &entry) == -1)
288 goto usage;
289 break;
290 case 'L':
291 if (gpt_name_get(gpt, &label) == -1)
292 goto usage;
293 break;
294 case 'b':
295 if (gpt_human_get(gpt, &start) == -1)
296 goto usage;
297 break;
298 default:
299 goto usage;
300 }
301 }
302
303 if (argc != optind)
304 return usage();
305
306 #ifdef USE_WEDGES
307 if ((gpt->sb.st_mode & S_IFMT) != S_IFREG &&
308 ioctl(gpt->fd, DIOCGWEDGEINFO, &dkw) != -1) {
309 if (entry > 0)
310 /* wedges and indexes are mutually exclusive */
311 goto usage;
312 start = dkw.dkw_offset;
313 size = dkw.dkw_size;
314 ngpt = gpt_open(dkw.dkw_parent, gpt->flags, gpt->verbose,
315 0, 0, 0);
316 if (ngpt == NULL)
317 goto cleanup;
318 }
319 #endif
320 if (biosboot(ngpt, start, size, entry, label, bootpath, active) == -1)
321 goto cleanup;
322 if (ngpt != gpt)
323 gpt_close(ngpt);
324 return 0;
325 usage:
326 usage();
327 cleanup:
328 if (ngpt != gpt)
329 gpt_close(ngpt);
330 free(bootpath);
331 free(label);
332 return -1;
333 }
334