1 /*
2 * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
31 #include <sys/disklabel.h>
32 #include <sys/diskmbr.h>
33 #include <sys/stat.h>
34
35 #include <err.h>
36 #include <errno.h>
37 #include <fcntl.h>
38 #include <libgeom.h>
39 #include <paths.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44
45 #define MBRSIZE 512 /* master boot record size */
46
47 #define OFF_VERSION 0x1b0 /* offset: version number, only boot0version */
48 #define OFF_SERIAL 0x1b8 /* offset: volume serial number */
49 #define OFF_PTBL 0x1be /* offset: partition table */
50 #define OFF_MAGIC 0x1fe /* offset: magic number */
51 /*
52 * Offsets to the parameters of the 512-byte boot block.
53 * For historical reasons they are set as macros
54 */
55 struct opt_offsets {
56 int opt;
57 int drive;
58 int flags;
59 int ticks;
60 };
61
62 static struct opt_offsets b0_ofs[] = {
63 { 0x0, 0x0, 0x0, 0x0 }, /* no boot block */
64 { 0x1b9, 0x1ba, 0x1bb, 0x1bc }, /* original block */
65 { 0x1b5, 0x1b6, 0x1b7, 0x1bc }, /* NT_SERIAL block */
66 };
67
68 static int b0_ver; /* boot block version set by boot0bs */
69
70 #define OFF_OPT (b0_ofs[b0_ver].opt) /* default boot option */
71 #define OFF_DRIVE (b0_ofs[b0_ver].drive) /* setdrv drive */
72 #define OFF_FLAGS (b0_ofs[b0_ver].flags) /* option flags */
73 #define OFF_TICKS (b0_ofs[b0_ver].ticks) /* clock ticks */
74
75
76 #define cv2(p) ((p)[0] | (p)[1] << 010)
77
78 #define mk2(p, x) \
79 (p)[0] = (u_int8_t)(x), \
80 (p)[1] = (u_int8_t)((x) >> 010)
81
82 static const struct {
83 const char *tok;
84 int def;
85 } opttbl[] = {
86 {"packet", 0},
87 {"update", 1},
88 {"setdrv", 0}
89 };
90 static const int nopt = nitems(opttbl);
91
92 static const char fmt0[] = "# flag start chs type"
93 " end chs offset size\n";
94
95 static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x"
96 " %4u:%3u:%2u %10u %10u\n";
97
98 static int geom_class_available(const char *);
99 static int read_mbr(const char *, u_int8_t **, int);
100 static void write_mbr(const char *, int, u_int8_t *, int, int);
101 static void display_mbr(u_int8_t *);
102 static int boot0version(const u_int8_t *);
103 static int boot0bs(const u_int8_t *);
104 static void stropt(const char *, int *, int *);
105 static int argtoi(const char *, int, int, int);
106 static int set_bell(u_int8_t *, int, int);
107 static void usage(void) __dead2;
108
109 static unsigned vol_id[5]; /* 4 plus 1 for flag */
110
111 static int v_flag;
112 /*
113 * Boot manager installation/configuration utility.
114 */
115 int
main(int argc,char * argv[])116 main(int argc, char *argv[])
117 {
118 struct stat sb;
119 u_int8_t *mbr, *boot0;
120 int boot0_size, mbr_size;
121 const char *bpath, *fpath;
122 char *disk;
123 int B_flag, o_flag;
124 int d_arg, m_arg, s_arg, t_arg;
125 int o_and, o_or, o_e = -1;
126 int up, c;
127
128 bpath = "/boot/boot0";
129 fpath = NULL;
130 B_flag = v_flag = o_flag = 0;
131 d_arg = m_arg = s_arg = t_arg = -1;
132 o_and = 0xff;
133 o_or = 0;
134 while ((c = getopt(argc, argv, "Bvb:d:e:f:i:m:o:s:t:")) != -1)
135 switch (c) {
136 case 'B':
137 B_flag = 1;
138 break;
139 case 'v':
140 v_flag = 1;
141 break;
142 case 'b':
143 bpath = optarg;
144 break;
145 case 'd':
146 d_arg = argtoi(optarg, 0, 0xff, 'd');
147 break;
148 case 'e':
149 if (optarg[0] == '0' && optarg[1] == 'x')
150 sscanf(optarg, "0x%02x", &o_e);
151 else
152 o_e = optarg[0];
153 break;
154 case 'f':
155 fpath = optarg;
156 break;
157 case 'i':
158 if (sscanf(optarg, "%02x%02x-%02x%02x",
159 vol_id, vol_id+1, vol_id+2, vol_id+3) == 4)
160 vol_id[4] = 1;
161 else
162 errx(1, "bad argument %s", optarg);
163 break;
164 case 'm':
165 m_arg = argtoi(optarg, 0, 0xf, 'm');
166 break;
167 case 'o':
168 stropt(optarg, &o_and, &o_or);
169 o_flag = 1;
170 break;
171 case 's':
172 if (strcasecmp(optarg, "pxe") == 0)
173 s_arg = 6;
174 else
175 s_arg = argtoi(optarg, 1, 6, 's');
176 break;
177 case 't':
178 t_arg = argtoi(optarg, 1, 0xffff, 't');
179 break;
180 default:
181 usage();
182 }
183 argc -= optind;
184 argv += optind;
185 if (argc != 1)
186 usage();
187 if (stat(*argv, &sb) == 0 && S_ISREG(sb.st_mode)) {
188 disk = strdup(*argv);
189 if (disk == NULL)
190 err(1, "strdup");
191 } else {
192 disk = g_device_path(*argv);
193 if (disk == NULL)
194 errx(1, "Unable to get providername for %s\n", *argv);
195 }
196 up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
197 || t_arg != -1;
198
199 /* open the disk and read in the existing mbr. Either here or
200 * when reading the block from disk, we do check for the version
201 * and abort if a suitable block is not found.
202 */
203 mbr_size = read_mbr(disk, &mbr, !B_flag);
204
205 /* save the existing MBR if we are asked to do so */
206 if (fpath)
207 write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size, 0);
208
209 /*
210 * If we are installing the boot loader, read it from disk and copy the
211 * slice table over from the existing MBR. If not, then point boot0
212 * back at the MBR we just read in. After this, boot0 is the data to
213 * write back to disk if we are going to do a write.
214 */
215 if (B_flag) {
216 boot0_size = read_mbr(bpath, &boot0, 1);
217 memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
218 sizeof(struct dos_partition) * NDOSPART);
219 if (b0_ver == 2) /* volume serial number support */
220 memcpy(boot0 + OFF_SERIAL, mbr + OFF_SERIAL, 4);
221 } else {
222 boot0 = mbr;
223 boot0_size = mbr_size;
224 }
225
226 /* set the drive */
227 if (d_arg != -1)
228 boot0[OFF_DRIVE] = d_arg;
229
230 /* set various flags */
231 if (m_arg != -1) {
232 boot0[OFF_FLAGS] &= 0xf0;
233 boot0[OFF_FLAGS] |= m_arg;
234 }
235 if (o_flag) {
236 boot0[OFF_FLAGS] &= o_and;
237 boot0[OFF_FLAGS] |= o_or;
238 }
239
240 /* set the default boot selection */
241 if (s_arg != -1)
242 boot0[OFF_OPT] = s_arg - 1;
243
244 /* set the timeout */
245 if (t_arg != -1)
246 mk2(boot0 + OFF_TICKS, t_arg);
247
248 /* set the bell char */
249 if (o_e != -1 && set_bell(boot0, o_e, 0) != -1)
250 up = 1;
251
252 if (vol_id[4]) {
253 if (b0_ver != 2)
254 errx(1, "incompatible boot block, cannot set volume ID");
255 boot0[OFF_SERIAL] = vol_id[0];
256 boot0[OFF_SERIAL+1] = vol_id[1];
257 boot0[OFF_SERIAL+2] = vol_id[2];
258 boot0[OFF_SERIAL+3] = vol_id[3];
259 up = 1; /* force update */
260 }
261 /* write the MBR back to disk */
262 if (up)
263 write_mbr(disk, 0, boot0, boot0_size, vol_id[4] || b0_ver == 1);
264
265 /* display the MBR */
266 if (v_flag)
267 display_mbr(boot0);
268
269 /* clean up */
270 if (mbr != boot0)
271 free(boot0);
272 free(mbr);
273 free(disk);
274
275 return 0;
276 }
277
278 /* get or set the 'bell' character to be used in case of errors.
279 * Lookup for a certain code sequence, return -1 if not found.
280 */
281 static int
set_bell(u_int8_t * mbr,int new_bell,int report)282 set_bell(u_int8_t *mbr, int new_bell, int report)
283 {
284 /* lookup sequence: 0x100 means skip, 0x200 means done */
285 static unsigned seq[] =
286 { 0xb0, 0x100, 0xe8, 0x100, 0x100, 0x30, 0xe4, 0x200 };
287 int ofs, i, c;
288 for (ofs = 0x60; ofs < 0x180; ofs++) { /* search range */
289 if (mbr[ofs] != seq[0]) /* search initial pattern */
290 continue;
291 for (i=0;; i++) {
292 if (seq[i] == 0x200) { /* found */
293 c = mbr[ofs+1];
294 if (!report)
295 mbr[ofs+1] = c = new_bell;
296 else
297 printf(" bell=%c (0x%x)",
298 (c >= ' ' && c < 0x7f) ? c : ' ', c);
299 return c;
300 }
301 if (seq[i] != 0x100 && seq[i] != mbr[ofs+i])
302 break;
303 }
304 }
305 warn("bell not found");
306 return -1;
307 }
308 /*
309 * Read in the MBR of the disk. If it is boot0, then use the version to
310 * read in all of it if necessary. Use pointers to return a malloc'd
311 * buffer containing the MBR and then return its size.
312 */
313 static int
read_mbr(const char * disk,u_int8_t ** mbr,int check_version)314 read_mbr(const char *disk, u_int8_t **mbr, int check_version)
315 {
316 u_int8_t buf[MBRSIZE];
317 int mbr_size, fd;
318 int ver;
319 ssize_t n;
320
321 if ((fd = open(disk, O_RDONLY)) == -1)
322 err(1, "open %s", disk);
323 if ((n = read(fd, buf, MBRSIZE)) == -1)
324 err(1, "read %s", disk);
325 if (n != MBRSIZE)
326 errx(1, "%s: short read", disk);
327 if (cv2(buf + OFF_MAGIC) != 0xaa55)
328 errx(1, "%s: bad magic", disk);
329
330 if (! (ver = boot0bs(buf))) {
331 if (check_version)
332 errx(1, "%s: unknown or incompatible boot code", disk);
333 } else if (boot0version(buf) == 0x101) {
334 mbr_size = 1024;
335 if ((*mbr = malloc(mbr_size)) == NULL)
336 errx(1, "%s: unable to allocate read buffer", disk);
337 if (lseek(fd, 0, SEEK_SET) == -1 ||
338 (n = read(fd, *mbr, mbr_size)) == -1)
339 err(1, "%s", disk);
340 if (n != mbr_size)
341 errx(1, "%s: short read", disk);
342 close(fd);
343 return (mbr_size);
344 }
345 if ((*mbr = malloc(sizeof(buf))) == NULL)
346 errx(1, "%s: unable to allocate MBR buffer", disk);
347 memcpy(*mbr, buf, sizeof(buf));
348 close(fd);
349
350 return sizeof(buf);
351 }
352
353 static int
geom_class_available(const char * name)354 geom_class_available(const char *name)
355 {
356 struct gclass *class;
357 struct gmesh mesh;
358 int error;
359
360 error = geom_gettree(&mesh);
361 if (error != 0)
362 errc(1, error, "Cannot get GEOM tree");
363
364 LIST_FOREACH(class, &mesh.lg_class, lg_class) {
365 if (strcmp(class->lg_name, name) == 0) {
366 geom_deletetree(&mesh);
367 return (1);
368 }
369 }
370
371 geom_deletetree(&mesh);
372 return (0);
373 }
374
375 /*
376 * Write out the mbr to the specified file.
377 */
378 static void
write_mbr(const char * fname,int flags,u_int8_t * mbr,int mbr_size,int disable_dsn)379 write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size,
380 int disable_dsn)
381 {
382 struct gctl_req *grq;
383 struct stat sb;
384 const char *errmsg;
385 char *pname;
386 ssize_t n;
387 int fd;
388
389 fd = open(fname, O_WRONLY | flags, 0666);
390 if (fd != -1) {
391 n = write(fd, mbr, mbr_size);
392 close(fd);
393 if (n != mbr_size)
394 errx(1, "%s: short write", fname);
395 return;
396 }
397
398 /*
399 * If we're called to write to a backup file, don't try to
400 * write through GEOM.
401 */
402 if (flags != 0)
403 err(1, "can't open file %s to write backup", fname);
404
405 /*
406 * Try to open it read only to pass to GEOM,
407 * or inspect if it's a regular file.
408 */
409 fd = open(fname, O_RDONLY);
410 if (fd == -1) {
411 warn("error opening %s", fname);
412 return;
413 }
414
415 /*
416 * If name is a regular file, re-open it in write-only mode
417 * and write the MBR straight to it.
418 */
419 if (fstat(fd, &sb) == 0 && S_ISREG(sb.st_mode)) {
420 close(fd);
421 fd = open(fname, O_WRONLY);
422 if (fd == -1)
423 err(1, "can't open %s for writing", fname);
424 n = write(fd, mbr, mbr_size);
425 close(fd);
426 if (n != mbr_size)
427 errx(1, "%s: short write", fname);
428 return;
429 }
430
431 pname = g_providername(fd);
432 close(fd);
433 if (pname == NULL) {
434 warn("error getting providername for %s", fname);
435 return;
436 }
437
438 /* Check that GEOM_PART is available */
439 if (geom_class_available("PART") != 0) {
440 grq = gctl_get_handle();
441 gctl_ro_param(grq, "class", -1, "PART");
442 gctl_ro_param(grq, "arg0", -1, pname);
443 gctl_ro_param(grq, "verb", -1, "bootcode");
444 gctl_ro_param(grq, "bootcode", mbr_size, mbr);
445 gctl_ro_param(grq, "flags", -1, "C");
446 if (disable_dsn)
447 gctl_ro_param(grq, "skip_dsn", sizeof(int),
448 &disable_dsn);
449 errmsg = gctl_issue(grq);
450 if (errmsg != NULL && errmsg[0] != '\0')
451 errx(1, "GEOM_PART: write bootcode to %s failed: %s",
452 fname, errmsg);
453 gctl_free(grq);
454 } else
455 errx(1, "can't write MBR to %s", fname);
456 free(pname);
457 }
458
459 /*
460 * Outputs an informative dump of the data in the MBR to stdout.
461 */
462 static void
display_mbr(u_int8_t * mbr)463 display_mbr(u_int8_t *mbr)
464 {
465 struct dos_partition *part;
466 int i, version;
467
468 part = (struct dos_partition *)(mbr + DOSPARTOFF);
469 printf(fmt0);
470 for (i = 0; i < NDOSPART; i++)
471 if (part[i].dp_typ)
472 printf(fmt1, 1 + i, part[i].dp_flag,
473 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
474 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
475 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
476 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
477 part[i].dp_size);
478 printf("\n");
479 version = boot0version(mbr);
480 printf("version=%d.%d drive=0x%x mask=0x%x ticks=%u",
481 version >> 8, version & 0xff, mbr[OFF_DRIVE],
482 mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
483 set_bell(mbr, 0, 1);
484 printf("\noptions=");
485 for (i = 0; i < nopt; i++) {
486 if (i)
487 printf(",");
488 if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
489 printf("no");
490 printf("%s", opttbl[i].tok);
491 }
492 printf("\n");
493 if (b0_ver == 2)
494 printf("volume serial ID %02x%02x-%02x%02x\n",
495 mbr[OFF_SERIAL], mbr[OFF_SERIAL+1],
496 mbr[OFF_SERIAL+2], mbr[OFF_SERIAL+3]);
497 printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
498 if (mbr[OFF_OPT] < 4)
499 printf("Slice %d", mbr[OFF_OPT] + 1);
500 else if (mbr[OFF_OPT] == 4)
501 printf("Drive 1");
502 else
503 printf("PXE");
504 printf(")\n");
505 }
506
507 /*
508 * Return the boot0 version with the minor revision in the low byte, and
509 * the major revision in the next higher byte.
510 */
511 static int
boot0version(const u_int8_t * bs)512 boot0version(const u_int8_t *bs)
513 {
514 /* Check for old version, and return 0x100 if found. */
515 int v = boot0bs(bs);
516 if (v != 0)
517 return v << 8;
518
519 /* We have a newer boot0, so extract the version number and return it. */
520 return *(const int *)(bs + OFF_VERSION) & 0xffff;
521 }
522
523 /* descriptor of a pattern to match.
524 * Start from the first entry trying to match the chunk of bytes,
525 * if you hit an entry with len=0 terminate the search and report
526 * off as the version. Otherwise skip to the next block after len=0
527 * An entry with len=0, off=0 is the end marker.
528 */
529 struct byte_pattern {
530 unsigned off;
531 unsigned len;
532 u_int8_t *key;
533 };
534
535 /*
536 * Decide if we have valid boot0 boot code by looking for
537 * characteristic byte sequences at fixed offsets.
538 */
539 static int
boot0bs(const u_int8_t * bs)540 boot0bs(const u_int8_t *bs)
541 {
542 /* the initial code sequence */
543 static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
544 0x8e, 0xd0, 0xbc, 0x00, 0x7c };
545 /* the drive id */
546 static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '};
547 static struct byte_pattern patterns[] = {
548 {0x0, sizeof(id0), id0},
549 {0x1b2, sizeof(id1), id1},
550 {1, 0, NULL},
551 {0x0, sizeof(id0), id0}, /* version with NT support */
552 {0x1ae, sizeof(id1), id1},
553 {2, 0, NULL},
554 {0, 0, NULL},
555 };
556 struct byte_pattern *p = patterns;
557
558 for (; p->off || p->len; p++) {
559 if (p->len == 0)
560 break;
561 if (!memcmp(bs + p->off, p->key, p->len)) /* match */
562 continue;
563 while (p->len) /* skip to next block */
564 p++;
565 }
566 b0_ver = p->off; /* XXX ugly side effect */
567 return p->off;
568 }
569
570 /*
571 * Adjust "and" and "or" masks for a -o option argument.
572 */
573 static void
stropt(const char * arg,int * xa,int * xo)574 stropt(const char *arg, int *xa, int *xo)
575 {
576 const char *q;
577 char *s, *s1;
578 int inv, i, x;
579
580 if (!(s = strdup(arg)))
581 err(1, NULL);
582 for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
583 if ((inv = !strncmp(q, "no", 2)))
584 q += 2;
585 for (i = 0; i < nopt; i++)
586 if (!strcmp(q, opttbl[i].tok))
587 break;
588 if (i == nopt)
589 errx(1, "%s: Unknown -o option", q);
590 if (opttbl[i].def)
591 inv ^= 1;
592 x = 1 << (7 - i);
593 if (inv)
594 *xa &= ~x;
595 else
596 *xo |= x;
597 }
598 free(s);
599 }
600
601 /*
602 * Convert and check an option argument.
603 */
604 static int
argtoi(const char * arg,int lo,int hi,int opt)605 argtoi(const char *arg, int lo, int hi, int opt)
606 {
607 char *s;
608 long x;
609
610 errno = 0;
611 x = strtol(arg, &s, 0);
612 if (errno || !*arg || *s || x < lo || x > hi)
613 errx(1, "%s: Bad argument to -%c option", arg, opt);
614 return x;
615 }
616
617 /*
618 * Display usage information.
619 */
620 static void
usage(void)621 usage(void)
622 {
623 fprintf(stderr, "%s\n%s\n",
624 "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
625 " [-o options] [-s slice] [-t ticks] disk | file");
626 exit(1);
627 }
628