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