1 /*
2 * Copyright (c) 1999 Robert Nordier
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
18 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
19 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
20 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
21 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
23 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
24 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * $FreeBSD: src/usr.sbin/boot0cfg/boot0cfg.c,v 1.7.2.4 2002/03/16 01:06:51 mikeh Exp $
27 */
28
29 #include <sys/param.h>
30 #include <sys/diskmbr.h>
31 #include <sys/stat.h>
32
33 #include <err.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <paths.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <unistd.h>
41 #include <fstab.h>
42
43 #define MBRSIZE 512 /* master boot record size */
44
45 #define OFF_VERSION 0x1b0 /* offset: version number */
46 #define OFF_OPT 0x1b9 /* offset: default boot option */
47 #define OFF_DRIVE 0x1ba /* offset: setdrv drive */
48 #define OFF_FLAGS 0x1bb /* offset: option flags */
49 #define OFF_TICKS 0x1bc /* offset: clock ticks */
50 #define OFF_PTBL 0x1be /* offset: partition table */
51
52 #define cv2(p) ((p)[0] | (p)[1] << 010)
53
54 #define mk2(p, x) \
55 (p)[0] = (u_int8_t)(x), \
56 (p)[1] = (u_int8_t)((x) >> 010)
57
58 static const struct {
59 const char *tok;
60 int def;
61 } opttbl[] = {
62 {"packet", 0},
63 {"update", 1},
64 {"setdrv", 0}
65 };
66 static const int nopt = NELEM(opttbl);
67
68 static const char fmt0[] = "# flag start chs type"
69 " end chs offset size\n";
70
71 static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x"
72 " %4u:%3u:%2u %10u %10u\n";
73
74 static int read_mbr(const char *, u_int8_t **, int);
75 static void write_mbr(const char *, int, u_int8_t *, int);
76 static void display_mbr(u_int8_t *);
77 static int boot0version(const u_int8_t *);
78 static int boot0bs(const u_int8_t *);
79 static void stropt(const char *, int *, int *);
80 static int argtoi(const char *, int, int, int);
81 static void usage(void);
82
83 /*
84 * Boot manager installation/configuration utility.
85 */
86 int
main(int argc,char * argv[])87 main(int argc, char *argv[])
88 {
89 u_int8_t *mbr, *boot0;
90 int boot0_size, mbr_size;
91 const char *bpath, *fpath;
92 char *disk;
93 int B_flag, v_flag, o_flag;
94 int d_arg, m_arg, s_arg, t_arg;
95 int o_and, o_or;
96 int up, c;
97
98 bpath = "/boot/boot0";
99 fpath = NULL;
100 B_flag = v_flag = o_flag = 0;
101 d_arg = m_arg = s_arg = t_arg = -1;
102 o_and = 0xff;
103 o_or = 0;
104 while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1)
105 switch (c) {
106 case 'B':
107 B_flag = 1;
108 break;
109 case 'v':
110 v_flag = 1;
111 break;
112 case 'b':
113 bpath = optarg;
114 break;
115 case 'd':
116 d_arg = argtoi(optarg, 0, 0xff, 'd');
117 break;
118 case 'f':
119 fpath = optarg;
120 break;
121 case 'm':
122 m_arg = argtoi(optarg, 0, 0xf, 'm');
123 break;
124 case 'o':
125 stropt(optarg, &o_and, &o_or);
126 o_flag = 1;
127 break;
128 case 's':
129 s_arg = argtoi(optarg, 1, 5, 's');
130 break;
131 case 't':
132 t_arg = argtoi(optarg, 1, 0xffff, 't');
133 break;
134 default:
135 usage();
136 }
137 argc -= optind;
138 argv += optind;
139 if (argc != 1)
140 usage();
141
142 disk = getdevpath(*argv, 0);
143 if (!disk)
144 err(1, "cannot open disk %s", disk);
145
146 up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
147 || t_arg != -1;
148
149 /* open the disk and read in the existing mbr */
150 mbr_size = read_mbr(disk, &mbr, !B_flag);
151
152 /* save the existing MBR if we are asked to do so */
153 if (fpath)
154 write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size);
155
156 /*
157 * If we are installing the boot loader, read it from disk and copy the
158 * slice table over from the existing MBR. If not, then point boot0
159 * back at the MBR we just read in. After this, boot0 is the data to
160 * write back to disk if we are going to do a write.
161 */
162 if (B_flag) {
163 boot0_size = read_mbr(bpath, &boot0, 1);
164 memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
165 sizeof(struct dos_partition) * NDOSPART);
166 } else {
167 boot0 = mbr;
168 boot0_size = mbr_size;
169 }
170
171 /* set the drive */
172 if (d_arg != -1)
173 boot0[OFF_DRIVE] = d_arg;
174
175 /* set various flags */
176 if (m_arg != -1) {
177 boot0[OFF_FLAGS] &= 0xf0;
178 boot0[OFF_FLAGS] |= m_arg;
179 }
180 if (o_flag) {
181 boot0[OFF_FLAGS] &= o_and;
182 boot0[OFF_FLAGS] |= o_or;
183 }
184
185 /* set the default boot selection */
186 if (s_arg != -1)
187 boot0[OFF_OPT] = s_arg - 1;
188
189 /* set the timeout */
190 if (t_arg != -1)
191 mk2(boot0 + OFF_TICKS, t_arg);
192
193 /* write the MBR back to disk */
194 if (up)
195 write_mbr(disk, 0, boot0, boot0_size);
196
197 /* display the MBR */
198 if (v_flag)
199 display_mbr(boot0);
200
201 /* clean up */
202 if (mbr != boot0)
203 free(boot0);
204 free(mbr);
205 free(disk);
206
207 return 0;
208 }
209
210 /*
211 * Read in the MBR of the disk. If it is boot0, then use the version to
212 * read in all of it if necessary. Use pointers to return a malloc'd
213 * buffer containing the MBR and then return its size.
214 */
215 static int
read_mbr(const char * disk,u_int8_t ** mbr,int check_version)216 read_mbr(const char *disk, u_int8_t **mbr, int check_version)
217 {
218 u_int8_t buf[MBRSIZE];
219 int mbr_size, fd;
220 ssize_t n;
221
222 if ((fd = open(disk, O_RDONLY)) == -1)
223 err(1, "open %s", disk);
224 if ((n = read(fd, buf, MBRSIZE)) == -1)
225 err(1, "read %s", disk);
226 if (n != MBRSIZE)
227 errx(1, "%s: short read", disk);
228 if (cv2(buf + DOSMAGICOFF) != DOSMAGIC)
229 errx(1, "%s: bad magic", disk);
230
231 if (!boot0bs(buf)) {
232 if (check_version)
233 errx(1, "%s: unknown or incompatible boot code", disk);
234 } else if (boot0version(buf) == 0x101) {
235 mbr_size = 1024;
236 if ((*mbr = malloc(mbr_size)) == NULL)
237 errx(1, "%s: unable to allocate read buffer", disk);
238 if (lseek(fd, 0, SEEK_SET) == -1 ||
239 (n = read(fd, *mbr, mbr_size)) == -1)
240 err(1, "%s", disk);
241 if (n != mbr_size)
242 errx(1, "%s: short read", disk);
243 close(fd);
244 return (mbr_size);
245 }
246
247 if ((*mbr = malloc(sizeof(buf))) == NULL)
248 errx(1, "%s: unable to allocate mbr buffer", disk);
249 memcpy(*mbr, buf, sizeof(buf));
250 close(fd);
251 return sizeof(buf);
252 }
253
254 /*
255 * Write out the mbr to the specified file.
256 */
257 static void
write_mbr(const char * fname,int flags,u_int8_t * mbr,int mbr_size)258 write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size)
259 {
260 int fd;
261 ssize_t n;
262
263 fd = open(fname, O_WRONLY | flags, 0666);
264 if (fd != -1) {
265 n = write(fd, mbr, mbr_size);
266 close(fd);
267 if (n != mbr_size)
268 errx(1, "%s: short write", fname);
269 return;
270 }
271 if (flags != 0)
272 err(1, "%s", fname);
273 err(1, "write_mbr: %s", fname);
274 }
275
276 /*
277 * Outputs an informative dump of the data in the MBR to stdout.
278 */
279 static void
display_mbr(u_int8_t * mbr)280 display_mbr(u_int8_t *mbr)
281 {
282 struct dos_partition *part;
283 int i, version;
284
285 part = (struct dos_partition *)(mbr + DOSPARTOFF);
286 printf(fmt0);
287 for (i = 0; i < NDOSPART; i++)
288 if (part[i].dp_typ)
289 printf(fmt1, 1 + i, part[i].dp_flag,
290 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
291 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
292 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
293 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
294 part[i].dp_size);
295 printf("\n");
296 version = boot0version(mbr);
297 printf("version=%d.%d drive=0x%x mask=0x%x ticks=%u\noptions=",
298 version >> 8, version & 0xff, mbr[OFF_DRIVE],
299 mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
300 for (i = 0; i < nopt; i++) {
301 if (i)
302 printf(",");
303 if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
304 printf("no");
305 printf("%s", opttbl[i].tok);
306 }
307 printf("\n");
308 printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
309 if (mbr[OFF_OPT] < 4)
310 printf("Slice %d", mbr[OFF_OPT] + 1);
311 else
312 printf("Drive 1");
313 printf(")\n");
314 }
315
316 /*
317 * Return the boot0 version with the minor revision in the low byte, and
318 * the major revision in the next higher byte.
319 */
320 static int
boot0version(const u_int8_t * bs)321 boot0version(const u_int8_t *bs)
322 {
323 static u_int8_t idold[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a};
324
325 /* Check for old version, and return 0x100 if found. */
326 if (memcmp(bs + 0x1c, idold, sizeof(idold)) == 0)
327 return 0x100;
328
329 /* We have a newer boot0, so extract the version number and return it. */
330 return *(const int *)(bs + OFF_VERSION) & 0xffff;
331 }
332
333 /*
334 * Decide if we have valid boot0 boot code by looking for
335 * characteristic byte sequences at fixed offsets.
336 */
337 static int
boot0bs(const u_int8_t * bs)338 boot0bs(const u_int8_t *bs)
339 {
340 static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
341 0x8e, 0xd0, 0xbc, 0x00, 0x7c };
342 static u_int8_t id1[] = {0xfc, 0xb8, 0x00, 0x09, 0x8e, 0xc0, 0x8e,
343 0xd0, 0xbc, 0x00, 0x10 ,0x31 };
344 static u_int8_t id2[] = {'D', 'r', 'i', 'v', 'e', ' '};
345 static struct {
346 unsigned off;
347 unsigned len;
348 u_int8_t *key;
349 } ident[] = {
350 {0x0, sizeof(id0), id0},
351 {0x0, sizeof(id1), id1},
352 {0x1b2, sizeof(id2), id2}
353 };
354 unsigned int i;
355 int count = 0;
356
357 for (i = 0; i < NELEM(ident); i++) {
358 if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len) == 0)
359 ++count;
360 }
361 if (count >= 2)
362 return 1;
363 return 0;
364 }
365
366 /*
367 * Adjust "and" and "or" masks for a -o option argument.
368 */
369 static void
stropt(const char * arg,int * xa,int * xo)370 stropt(const char *arg, int *xa, int *xo)
371 {
372 const char *q;
373 char *s, *s1;
374 int inv, i, x;
375
376 if (!(s = strdup(arg)))
377 err(1, NULL);
378 for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
379 if ((inv = !strncmp(q, "no", 2)))
380 q += 2;
381 for (i = 0; i < nopt; i++)
382 if (!strcmp(q, opttbl[i].tok))
383 break;
384 if (i == nopt)
385 errx(1, "%s: Unknown -o option", q);
386 if (opttbl[i].def)
387 inv ^= 1;
388 x = 1 << (7 - i);
389 if (inv)
390 *xa &= ~x;
391 else
392 *xo |= x;
393 }
394 free(s);
395 }
396
397 /*
398 * Convert and check an option argument.
399 */
400 static int
argtoi(const char * arg,int lo,int hi,int opt)401 argtoi(const char *arg, int lo, int hi, int opt)
402 {
403 char *s;
404 long x;
405
406 errno = 0;
407 x = strtol(arg, &s, 0);
408 if (errno || !*arg || *s || x < lo || x > hi)
409 errx(1, "%s: Bad argument to -%c option", arg, opt);
410 return x;
411 }
412
413 /*
414 * Display usage information.
415 */
416 static void
usage(void)417 usage(void)
418 {
419 fprintf(stderr, "%s\n%s\n",
420 "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
421 " [-o options] [-s slice] [-t ticks] disk");
422 exit(1);
423 }
424