1 /*
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2008 Luigi Rizzo
5 * Copyright (c) 1999 Robert Nordier
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
22 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
23 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
24 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
26 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
27 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32
33 #include <sys/param.h>
34 #include <sys/disklabel.h>
35 #include <sys/diskmbr.h>
36 #include <sys/stat.h>
37
38 #include <err.h>
39 #include <errno.h>
40 #include <fcntl.h>
41 #include <libgeom.h>
42 #include <paths.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <unistd.h>
47
48 #define MBRSIZE 512 /* master boot record size */
49
50 #define OFF_VERSION 0x1b0 /* offset: version number, only boot0version */
51 #define OFF_SERIAL 0x1b8 /* offset: volume serial number */
52 #define OFF_PTBL 0x1be /* offset: partition table */
53 #define OFF_MAGIC 0x1fe /* offset: magic number */
54 /*
55 * Offsets to the parameters of the 512-byte boot block.
56 * For historical reasons they are set as macros
57 */
58 struct opt_offsets {
59 int opt;
60 int drive;
61 int flags;
62 int ticks;
63 };
64
65 static struct opt_offsets b0_ofs[] = {
66 { 0x0, 0x0, 0x0, 0x0 }, /* no boot block */
67 { 0x1b9, 0x1ba, 0x1bb, 0x1bc }, /* original block */
68 { 0x1b5, 0x1b6, 0x1b7, 0x1bc }, /* NT_SERIAL block */
69 };
70
71 static int b0_ver; /* boot block version set by boot0bs */
72
73 #define OFF_OPT (b0_ofs[b0_ver].opt) /* default boot option */
74 #define OFF_DRIVE (b0_ofs[b0_ver].drive) /* setdrv drive */
75 #define OFF_FLAGS (b0_ofs[b0_ver].flags) /* option flags */
76 #define OFF_TICKS (b0_ofs[b0_ver].ticks) /* clock ticks */
77
78
79 #define cv2(p) ((p)[0] | (p)[1] << 010)
80
81 #define mk2(p, x) \
82 (p)[0] = (u_int8_t)(x), \
83 (p)[1] = (u_int8_t)((x) >> 010)
84
85 static const struct {
86 const char *tok;
87 int def;
88 } opttbl[] = {
89 {"packet", 0},
90 {"update", 1},
91 {"setdrv", 0}
92 };
93 static const int nopt = nitems(opttbl);
94
95 static const char fmt0[] = "# flag start chs type"
96 " end chs offset size\n";
97
98 static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x"
99 " %4u:%3u:%2u %10u %10u\n";
100
101 static int geom_class_available(const char *);
102 static int read_mbr(const char *, u_int8_t **, int);
103 static void write_mbr(const char *, int, u_int8_t *, int, int);
104 static void display_mbr(u_int8_t *);
105 static int boot0version(const u_int8_t *);
106 static int boot0bs(const u_int8_t *);
107 static void stropt(const char *, int *, int *);
108 static int argtoi(const char *, int, int, int);
109 static int set_bell(u_int8_t *, int, int);
110 static void usage(void);
111
112 static unsigned vol_id[5]; /* 4 plus 1 for flag */
113
114 static int v_flag;
115 /*
116 * Boot manager installation/configuration utility.
117 */
118 int
main(int argc,char * argv[])119 main(int argc, char *argv[])
120 {
121 u_int8_t *mbr, *boot0;
122 int boot0_size, mbr_size;
123 const char *bpath, *fpath;
124 char *disk;
125 int B_flag, o_flag;
126 int d_arg, m_arg, s_arg, t_arg;
127 int o_and, o_or, o_e = -1;
128 int up, c;
129
130 bpath = "/boot/boot0";
131 fpath = NULL;
132 B_flag = v_flag = o_flag = 0;
133 d_arg = m_arg = s_arg = t_arg = -1;
134 o_and = 0xff;
135 o_or = 0;
136 while ((c = getopt(argc, argv, "Bvb:d:e:f:i:m:o:s:t:")) != -1)
137 switch (c) {
138 case 'B':
139 B_flag = 1;
140 break;
141 case 'v':
142 v_flag = 1;
143 break;
144 case 'b':
145 bpath = optarg;
146 break;
147 case 'd':
148 d_arg = argtoi(optarg, 0, 0xff, 'd');
149 break;
150 case 'e':
151 if (optarg[0] == '0' && optarg[1] == 'x')
152 sscanf(optarg, "0x%02x", &o_e);
153 else
154 o_e = optarg[0];
155 break;
156 case 'f':
157 fpath = optarg;
158 break;
159 case 'i':
160 if (sscanf(optarg, "%02x%02x-%02x%02x",
161 vol_id, vol_id+1, vol_id+2, vol_id+3) == 4)
162 vol_id[4] = 1;
163 else
164 errx(1, "bad argument %s", optarg);
165 break;
166 case 'm':
167 m_arg = argtoi(optarg, 0, 0xf, 'm');
168 break;
169 case 'o':
170 stropt(optarg, &o_and, &o_or);
171 o_flag = 1;
172 break;
173 case 's':
174 if (strcasecmp(optarg, "pxe") == 0)
175 s_arg = 6;
176 else
177 s_arg = argtoi(optarg, 1, 6, 's');
178 break;
179 case 't':
180 t_arg = argtoi(optarg, 1, 0xffff, 't');
181 break;
182 default:
183 usage();
184 }
185 argc -= optind;
186 argv += optind;
187 if (argc != 1)
188 usage();
189 disk = g_device_path(*argv);
190 if (disk == NULL)
191 errx(1, "Unable to get providername for %s\n", *argv);
192 up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
193 || t_arg != -1;
194
195 /* open the disk and read in the existing mbr. Either here or
196 * when reading the block from disk, we do check for the version
197 * and abort if a suitable block is not found.
198 */
199 mbr_size = read_mbr(disk, &mbr, !B_flag);
200
201 /* save the existing MBR if we are asked to do so */
202 if (fpath)
203 write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size, 0);
204
205 /*
206 * If we are installing the boot loader, read it from disk and copy the
207 * slice table over from the existing MBR. If not, then point boot0
208 * back at the MBR we just read in. After this, boot0 is the data to
209 * write back to disk if we are going to do a write.
210 */
211 if (B_flag) {
212 boot0_size = read_mbr(bpath, &boot0, 1);
213 memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
214 sizeof(struct dos_partition) * NDOSPART);
215 if (b0_ver == 2) /* volume serial number support */
216 memcpy(boot0 + OFF_SERIAL, mbr + OFF_SERIAL, 4);
217 } else {
218 boot0 = mbr;
219 boot0_size = mbr_size;
220 }
221
222 /* set the drive */
223 if (d_arg != -1)
224 boot0[OFF_DRIVE] = d_arg;
225
226 /* set various flags */
227 if (m_arg != -1) {
228 boot0[OFF_FLAGS] &= 0xf0;
229 boot0[OFF_FLAGS] |= m_arg;
230 }
231 if (o_flag) {
232 boot0[OFF_FLAGS] &= o_and;
233 boot0[OFF_FLAGS] |= o_or;
234 }
235
236 /* set the default boot selection */
237 if (s_arg != -1)
238 boot0[OFF_OPT] = s_arg - 1;
239
240 /* set the timeout */
241 if (t_arg != -1)
242 mk2(boot0 + OFF_TICKS, t_arg);
243
244 /* set the bell char */
245 if (o_e != -1 && set_bell(boot0, o_e, 0) != -1)
246 up = 1;
247
248 if (vol_id[4]) {
249 if (b0_ver != 2)
250 errx(1, "incompatible boot block, cannot set volume ID");
251 boot0[OFF_SERIAL] = vol_id[0];
252 boot0[OFF_SERIAL+1] = vol_id[1];
253 boot0[OFF_SERIAL+2] = vol_id[2];
254 boot0[OFF_SERIAL+3] = vol_id[3];
255 up = 1; /* force update */
256 }
257 /* write the MBR back to disk */
258 if (up)
259 write_mbr(disk, 0, boot0, boot0_size, vol_id[4] || b0_ver == 1);
260
261 /* display the MBR */
262 if (v_flag)
263 display_mbr(boot0);
264
265 /* clean up */
266 if (mbr != boot0)
267 free(boot0);
268 free(mbr);
269 free(disk);
270
271 return 0;
272 }
273
274 /* get or set the 'bell' character to be used in case of errors.
275 * Lookup for a certain code sequence, return -1 if not found.
276 */
277 static int
set_bell(u_int8_t * mbr,int new_bell,int report)278 set_bell(u_int8_t *mbr, int new_bell, int report)
279 {
280 /* lookup sequence: 0x100 means skip, 0x200 means done */
281 static unsigned seq[] =
282 { 0xb0, 0x100, 0xe8, 0x100, 0x100, 0x30, 0xe4, 0x200 };
283 int ofs, i, c;
284 for (ofs = 0x60; ofs < 0x180; ofs++) { /* search range */
285 if (mbr[ofs] != seq[0]) /* search initial pattern */
286 continue;
287 for (i=0;; i++) {
288 if (seq[i] == 0x200) { /* found */
289 c = mbr[ofs+1];
290 if (!report)
291 mbr[ofs+1] = c = new_bell;
292 else
293 printf(" bell=%c (0x%x)",
294 (c >= ' ' && c < 0x7f) ? c : ' ', c);
295 return c;
296 }
297 if (seq[i] != 0x100 && seq[i] != mbr[ofs+i])
298 break;
299 }
300 }
301 warn("bell not found");
302 return -1;
303 }
304 /*
305 * Read in the MBR of the disk. If it is boot0, then use the version to
306 * read in all of it if necessary. Use pointers to return a malloc'd
307 * buffer containing the MBR and then return its size.
308 */
309 static int
read_mbr(const char * disk,u_int8_t ** mbr,int check_version)310 read_mbr(const char *disk, u_int8_t **mbr, int check_version)
311 {
312 u_int8_t buf[MBRSIZE];
313 int mbr_size, fd;
314 int ver;
315 ssize_t n;
316
317 if ((fd = open(disk, O_RDONLY)) == -1)
318 err(1, "open %s", disk);
319 if ((n = read(fd, buf, MBRSIZE)) == -1)
320 err(1, "read %s", disk);
321 if (n != MBRSIZE)
322 errx(1, "%s: short read", disk);
323 if (cv2(buf + OFF_MAGIC) != 0xaa55)
324 errx(1, "%s: bad magic", disk);
325
326 if (! (ver = boot0bs(buf))) {
327 if (check_version)
328 errx(1, "%s: unknown or incompatible boot code", disk);
329 } else if (boot0version(buf) == 0x101) {
330 mbr_size = 1024;
331 if ((*mbr = malloc(mbr_size)) == NULL)
332 errx(1, "%s: unable to allocate read buffer", disk);
333 if (lseek(fd, 0, SEEK_SET) == -1 ||
334 (n = read(fd, *mbr, mbr_size)) == -1)
335 err(1, "%s", disk);
336 if (n != mbr_size)
337 errx(1, "%s: short read", disk);
338 close(fd);
339 return (mbr_size);
340 }
341 if ((*mbr = malloc(sizeof(buf))) == NULL)
342 errx(1, "%s: unable to allocate MBR buffer", disk);
343 memcpy(*mbr, buf, sizeof(buf));
344 close(fd);
345
346 return sizeof(buf);
347 }
348
349 static int
geom_class_available(const char * name)350 geom_class_available(const char *name)
351 {
352 struct gclass *class;
353 struct gmesh mesh;
354 int error;
355
356 error = geom_gettree(&mesh);
357 if (error != 0)
358 errc(1, error, "Cannot get GEOM tree");
359
360 LIST_FOREACH(class, &mesh.lg_class, lg_class) {
361 if (strcmp(class->lg_name, name) == 0) {
362 geom_deletetree(&mesh);
363 return (1);
364 }
365 }
366
367 geom_deletetree(&mesh);
368 return (0);
369 }
370
371 /*
372 * Write out the mbr to the specified file.
373 */
374 static void
write_mbr(const char * fname,int flags,u_int8_t * mbr,int mbr_size,int disable_dsn)375 write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size,
376 int disable_dsn)
377 {
378 struct gctl_req *grq;
379 const char *errmsg;
380 char *pname;
381 ssize_t n;
382 int fd;
383
384 fd = open(fname, O_WRONLY | flags, 0666);
385 if (fd != -1) {
386 n = write(fd, mbr, mbr_size);
387 close(fd);
388 if (n != mbr_size)
389 errx(1, "%s: short write", fname);
390 return;
391 }
392
393 /*
394 * If we're called to write to a backup file, don't try to
395 * write through GEOM.
396 */
397 if (flags != 0)
398 err(1, "can't open file %s to write backup", fname);
399
400 /* Try open it read only. */
401 fd = open(fname, O_RDONLY);
402 if (fd == -1) {
403 warn("error opening %s", fname);
404 return;
405 }
406
407 pname = g_providername(fd);
408 if (pname == NULL) {
409 warn("error getting providername for %s", fname);
410 return;
411 }
412
413 /* First check that GEOM_PART is available */
414 if (geom_class_available("PART") != 0) {
415 grq = gctl_get_handle();
416 gctl_ro_param(grq, "class", -1, "PART");
417 gctl_ro_param(grq, "arg0", -1, pname);
418 gctl_ro_param(grq, "verb", -1, "bootcode");
419 gctl_ro_param(grq, "bootcode", mbr_size, mbr);
420 gctl_ro_param(grq, "flags", -1, "C");
421 if (disable_dsn)
422 gctl_ro_param(grq, "skip_dsn", sizeof(int),
423 &disable_dsn);
424 errmsg = gctl_issue(grq);
425 if (errmsg != NULL && errmsg[0] != '\0')
426 errx(1, "GEOM_PART: write bootcode to %s failed: %s",
427 fname, errmsg);
428 gctl_free(grq);
429 } else
430 errx(1, "can't write MBR to %s", fname);
431 free(pname);
432 }
433
434 /*
435 * Outputs an informative dump of the data in the MBR to stdout.
436 */
437 static void
display_mbr(u_int8_t * mbr)438 display_mbr(u_int8_t *mbr)
439 {
440 struct dos_partition *part;
441 int i, version;
442
443 part = (struct dos_partition *)(mbr + DOSPARTOFF);
444 printf(fmt0);
445 for (i = 0; i < NDOSPART; i++)
446 if (part[i].dp_typ)
447 printf(fmt1, 1 + i, part[i].dp_flag,
448 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
449 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
450 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
451 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
452 part[i].dp_size);
453 printf("\n");
454 version = boot0version(mbr);
455 printf("version=%d.%d drive=0x%x mask=0x%x ticks=%u",
456 version >> 8, version & 0xff, mbr[OFF_DRIVE],
457 mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
458 set_bell(mbr, 0, 1);
459 printf("\noptions=");
460 for (i = 0; i < nopt; i++) {
461 if (i)
462 printf(",");
463 if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
464 printf("no");
465 printf("%s", opttbl[i].tok);
466 }
467 printf("\n");
468 if (b0_ver == 2)
469 printf("volume serial ID %02x%02x-%02x%02x\n",
470 mbr[OFF_SERIAL], mbr[OFF_SERIAL+1],
471 mbr[OFF_SERIAL+2], mbr[OFF_SERIAL+3]);
472 printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
473 if (mbr[OFF_OPT] < 4)
474 printf("Slice %d", mbr[OFF_OPT] + 1);
475 else if (mbr[OFF_OPT] == 4)
476 printf("Drive 1");
477 else
478 printf("PXE");
479 printf(")\n");
480 }
481
482 /*
483 * Return the boot0 version with the minor revision in the low byte, and
484 * the major revision in the next higher byte.
485 */
486 static int
boot0version(const u_int8_t * bs)487 boot0version(const u_int8_t *bs)
488 {
489 /* Check for old version, and return 0x100 if found. */
490 int v = boot0bs(bs);
491 if (v != 0)
492 return v << 8;
493
494 /* We have a newer boot0, so extract the version number and return it. */
495 return *(const int *)(bs + OFF_VERSION) & 0xffff;
496 }
497
498 /* descriptor of a pattern to match.
499 * Start from the first entry trying to match the chunk of bytes,
500 * if you hit an entry with len=0 terminate the search and report
501 * off as the version. Otherwise skip to the next block after len=0
502 * An entry with len=0, off=0 is the end marker.
503 */
504 struct byte_pattern {
505 unsigned off;
506 unsigned len;
507 u_int8_t *key;
508 };
509
510 /*
511 * Decide if we have valid boot0 boot code by looking for
512 * characteristic byte sequences at fixed offsets.
513 */
514 static int
boot0bs(const u_int8_t * bs)515 boot0bs(const u_int8_t *bs)
516 {
517 /* the initial code sequence */
518 static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
519 0x8e, 0xd0, 0xbc, 0x00, 0x7c };
520 /* the drive id */
521 static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '};
522 static struct byte_pattern patterns[] = {
523 {0x0, sizeof(id0), id0},
524 {0x1b2, sizeof(id1), id1},
525 {1, 0, NULL},
526 {0x0, sizeof(id0), id0}, /* version with NT support */
527 {0x1ae, sizeof(id1), id1},
528 {2, 0, NULL},
529 {0, 0, NULL},
530 };
531 struct byte_pattern *p = patterns;
532
533 for (; p->off || p->len; p++) {
534 if (p->len == 0)
535 break;
536 if (!memcmp(bs + p->off, p->key, p->len)) /* match */
537 continue;
538 while (p->len) /* skip to next block */
539 p++;
540 }
541 b0_ver = p->off; /* XXX ugly side effect */
542 return p->off;
543 }
544
545 /*
546 * Adjust "and" and "or" masks for a -o option argument.
547 */
548 static void
stropt(const char * arg,int * xa,int * xo)549 stropt(const char *arg, int *xa, int *xo)
550 {
551 const char *q;
552 char *s, *s1;
553 int inv, i, x;
554
555 if (!(s = strdup(arg)))
556 err(1, NULL);
557 for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
558 if ((inv = !strncmp(q, "no", 2)))
559 q += 2;
560 for (i = 0; i < nopt; i++)
561 if (!strcmp(q, opttbl[i].tok))
562 break;
563 if (i == nopt)
564 errx(1, "%s: Unknown -o option", q);
565 if (opttbl[i].def)
566 inv ^= 1;
567 x = 1 << (7 - i);
568 if (inv)
569 *xa &= ~x;
570 else
571 *xo |= x;
572 }
573 free(s);
574 }
575
576 /*
577 * Convert and check an option argument.
578 */
579 static int
argtoi(const char * arg,int lo,int hi,int opt)580 argtoi(const char *arg, int lo, int hi, int opt)
581 {
582 char *s;
583 long x;
584
585 errno = 0;
586 x = strtol(arg, &s, 0);
587 if (errno || !*arg || *s || x < lo || x > hi)
588 errx(1, "%s: Bad argument to -%c option", arg, opt);
589 return x;
590 }
591
592 /*
593 * Display usage information.
594 */
595 static void
usage(void)596 usage(void)
597 {
598 fprintf(stderr, "%s\n%s\n",
599 "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
600 " [-o options] [-s slice] [-t ticks] disk");
601 exit(1);
602 }
603