usr.sbin/boot0cfg/boot0cfg.c

   1 /*
   2  * Copyright (c) 2008 Luigi Rizzo
   3  * Copyright (c) 1999 Robert Nordier
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  18  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
  19  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  20  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  21  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  22  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
  24  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  25  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/param.h>
  32 #include <sys/disklabel.h>
  33 #include <sys/diskmbr.h>
  34 #include <sys/stat.h>
  35
  36 #include <err.h>
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <libgeom.h>
  40 #include <paths.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <unistd.h>
  45
  46 #define MBRSIZE         512     /* master boot record size */
  47
  48 #define OFF_VERSION     0x1b0   /* offset: version number, only boot0version */
  49 #define OFF_SERIAL      0x1b8   /* offset: volume serial number */
  50 #define OFF_PTBL        0x1be   /* offset: partition table */
  51 #define OFF_MAGIC       0x1fe   /* offset: magic number */
  52 /*
  53  * Offsets to the parameters of the 512-byte boot block.
  54  * For historical reasons they are set as macros
  55  */
  56 struct opt_offsets {
  57         int opt;
  58         int drive;
  59         int flags;
  60         int ticks;
  61 };
  62
  63 static struct opt_offsets b0_ofs[] = {
  64         { 0x0, 0x0, 0x0, 0x0 },         /* no boot block */
  65         { 0x1b9, 0x1ba, 0x1bb, 0x1bc }, /* original block */
  66         { 0x1b5, 0x1b6, 0x1b7, 0x1bc }, /* NT_SERIAL block */
  67 };
  68
  69 static int b0_ver;      /* boot block version set by boot0bs */
  70
  71 #define OFF_OPT         (b0_ofs[b0_ver].opt)    /* default boot option */
  72 #define OFF_DRIVE       (b0_ofs[b0_ver].drive)  /* setdrv drive */
  73 #define OFF_FLAGS       (b0_ofs[b0_ver].flags)  /* option flags */
  74 #define OFF_TICKS       (b0_ofs[b0_ver].ticks)  /* clock ticks */
  75
  76
  77 #define cv2(p)  ((p)[0] | (p)[1] << 010)
  78
  79 #define mk2(p, x)                               \
  80     (p)[0] = (u_int8_t)(x),                     \
  81     (p)[1] = (u_int8_t)((x) >> 010)
  82
  83 static const struct {
  84     const char *tok;
  85     int def;
  86 } opttbl[] = {
  87     {"packet", 0},
  88     {"update", 1},
  89     {"setdrv", 0}
  90 };
  91 static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]);
  92
  93 static const char fmt0[] = "#   flag     start chs   type"
  94     "       end chs       offset         size\n";
  95
  96 static const char fmt1[] = "%d   0x%02x   %4u:%3u:%2u   0x%02x"
  97     "   %4u:%3u:%2u   %10u   %10u\n";
  98
  99 static int geom_class_available(const char *);
 100 static int read_mbr(const char *, u_int8_t **, int);
 101 static void write_mbr(const char *, int, u_int8_t *, int);
 102 static void display_mbr(u_int8_t *);
 103 static int boot0version(const u_int8_t *);
 104 static int boot0bs(const u_int8_t *);
 105 static void stropt(const char *, int *, int *);
 106 static int argtoi(const char *, int, int, int);
 107 static int set_bell(u_int8_t *, int, int);
 108 static void usage(void);
 109
 110 static unsigned vol_id[5];      /* 4 plus 1 for flag */
 111
 112 static int v_flag;
 113 /*
 114  * Boot manager installation/configuration utility.
 115  */
 116 int
 117 main(int argc, char *argv[])
 118 {
 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     disk = g_device_path(*argv);
 188     if (disk == NULL)
 189         errx(1, "Unable to get providername for %s\n", *argv);
 190     up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
 191         || t_arg != -1;
 192
 193     /* open the disk and read in the existing mbr. Either here or
 194      * when reading the block from disk, we do check for the version
 195      * and abort if a suitable block is not found.
 196      */
 197     mbr_size = read_mbr(disk, &mbr, !B_flag);
 198
 199     /* save the existing MBR if we are asked to do so */
 200     if (fpath)
 201         write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size);
 202
 203     /*
 204      * If we are installing the boot loader, read it from disk and copy the
 205      * slice table over from the existing MBR.  If not, then point boot0
 206      * back at the MBR we just read in.  After this, boot0 is the data to
 207      * write back to disk if we are going to do a write.
 208      */
 209     if (B_flag) {
 210         boot0_size = read_mbr(bpath, &boot0, 1);
 211         memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
 212             sizeof(struct dos_partition) * NDOSPART);
 213         if (b0_ver == 2)        /* volume serial number support */
 214             memcpy(boot0 + OFF_SERIAL, mbr + OFF_SERIAL, 4);
 215     } else {
 216         boot0 = mbr;
 217         boot0_size = mbr_size;
 218     }
 219
 220     /* set the drive */
 221     if (d_arg != -1)
 222         boot0[OFF_DRIVE] = d_arg;
 223
 224     /* set various flags */
 225     if (m_arg != -1) {
 226         boot0[OFF_FLAGS] &= 0xf0;
 227         boot0[OFF_FLAGS] |= m_arg;
 228     }
 229     if (o_flag) {
 230         boot0[OFF_FLAGS] &= o_and;
 231         boot0[OFF_FLAGS] |= o_or;
 232     }
 233
 234     /* set the default boot selection */
 235     if (s_arg != -1)
 236         boot0[OFF_OPT] = s_arg - 1;
 237
 238     /* set the timeout */
 239     if (t_arg != -1)
 240         mk2(boot0 + OFF_TICKS, t_arg);
 241
 242     /* set the bell char */
 243     if (o_e != -1 && set_bell(boot0, o_e, 0) != -1)
 244         up = 1;
 245
 246     if (vol_id[4]) {
 247         if (b0_ver != 2)
 248             errx(1, "incompatible boot block, cannot set volume ID");
 249         boot0[OFF_SERIAL] = vol_id[0];
 250         boot0[OFF_SERIAL+1] = vol_id[1];
 251         boot0[OFF_SERIAL+2] = vol_id[2];
 252         boot0[OFF_SERIAL+3] = vol_id[3];
 253         up = 1; /* force update */
 254     }
 255     /* write the MBR back to disk */
 256     if (up)
 257         write_mbr(disk, 0, boot0, boot0_size);
 258
 259     /* display the MBR */
 260     if (v_flag)
 261         display_mbr(boot0);
 262
 263     /* clean up */
 264     if (mbr != boot0)
 265         free(boot0);
 266     free(mbr);
 267     free(disk);
 268
 269     return 0;
 270 }
 271
 272 /* get or set the 'bell' character to be used in case of errors.
 273  * Lookup for a certain code sequence, return -1 if not found.
 274  */
 275 static int
 276 set_bell(u_int8_t *mbr, int new_bell, int report)
 277 {
 278     /* lookup sequence: 0x100 means skip, 0x200 means done */
 279     static unsigned seq[] =
 280                 { 0xb0, 0x100, 0xe8, 0x100, 0x100, 0x30, 0xe4, 0x200 };
 281     int ofs, i, c;
 282     for (ofs = 0x60; ofs < 0x180; ofs++) { /* search range */
 283         if (mbr[ofs] != seq[0]) /* search initial pattern */
 284             continue;
 285         for (i=0;; i++) {
 286             if (seq[i] == 0x200) {      /* found */
 287                 c = mbr[ofs+1];
 288                 if (!report)
 289                     mbr[ofs+1] = c = new_bell;
 290                 else
 291                     printf("  bell=%c (0x%x)",
 292                         (c >= ' ' && c < 0x7f) ? c : ' ', c);
 293                 return c;
 294             }
 295             if (seq[i] != 0x100 && seq[i] != mbr[ofs+i])
 296                 break;
 297         }
 298     }
 299     warn("bell not found");
 300     return -1;
 301 }
 302 /*
 303  * Read in the MBR of the disk.  If it is boot0, then use the version to
 304  * read in all of it if necessary.  Use pointers to return a malloc'd
 305  * buffer containing the MBR and then return its size.
 306  */
 307 static int
 308 read_mbr(const char *disk, u_int8_t **mbr, int check_version)
 309 {
 310     u_int8_t buf[MBRSIZE];
 311     int mbr_size, fd;
 312     int ver;
 313     ssize_t n;
 314
 315     if ((fd = open(disk, O_RDONLY)) == -1)
 316         err(1, "open %s", disk);
 317     if ((n = read(fd, buf, MBRSIZE)) == -1)
 318         err(1, "read %s", disk);
 319     if (n != MBRSIZE)
 320         errx(1, "%s: short read", disk);
 321     if (cv2(buf + OFF_MAGIC) != 0xaa55)
 322         errx(1, "%s: bad magic", disk);
 323
 324     if (! (ver = boot0bs(buf))) {
 325         if (check_version)
 326             errx(1, "%s: unknown or incompatible boot code", disk);
 327     } else if (boot0version(buf) == 0x101) {
 328         mbr_size = 1024;
 329         if ((*mbr = malloc(mbr_size)) == NULL)
 330             errx(1, "%s: unable to allocate read buffer", disk);
 331         if (lseek(fd, 0, SEEK_SET) == -1 ||
 332             (n = read(fd, *mbr, mbr_size)) == -1)
 333             err(1, "%s", disk);
 334         if (n != mbr_size)
 335             errx(1, "%s: short read", disk);
 336         close(fd);
 337         return (mbr_size);
 338     }
 339     if ((*mbr = malloc(sizeof(buf))) == NULL)
 340         errx(1, "%s: unable to allocate MBR buffer", disk);
 341     memcpy(*mbr, buf, sizeof(buf));
 342     close(fd);
 343
 344     return sizeof(buf);
 345 }
 346
 347 static int
 348 geom_class_available(const char *name)
 349 {
 350         struct gclass *class;
 351         struct gmesh mesh;
 352         int error;
 353
 354         error = geom_gettree(&mesh);
 355         if (error != 0)
 356                 errc(1, error, "Cannot get GEOM tree");
 357
 358         LIST_FOREACH(class, &mesh.lg_class, lg_class) {
 359                 if (strcmp(class->lg_name, name) == 0) {
 360                         geom_deletetree(&mesh);
 361                         return (1);
 362                 }
 363         }
 364
 365         geom_deletetree(&mesh);
 366         return (0);
 367 }
 368
 369 /*
 370  * Write out the mbr to the specified file.
 371  */
 372 static void
 373 write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size)
 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                 errmsg = gctl_issue(grq);
 419                 if (errmsg != NULL && errmsg[0] != '\0')
 420                         errx(1, "GEOM_PART: write bootcode to %s failed: %s",
 421                             fname, errmsg);
 422                 gctl_free(grq);
 423         } else if (geom_class_available("MBR") != 0) {
 424                 grq = gctl_get_handle();
 425                 gctl_ro_param(grq, "verb", -1, "write MBR");
 426                 gctl_ro_param(grq, "class", -1, "MBR");
 427                 gctl_ro_param(grq, "geom", -1, pname);
 428                 gctl_ro_param(grq, "data", mbr_size, mbr);
 429                 errmsg = gctl_issue(grq);
 430                 if (errmsg != NULL)
 431                         err(1, "GEOM_MBR: write MBR to %s failed", fname);
 432                 gctl_free(grq);
 433         } else
 434                 errx(1, "can't write MBR to %s", fname);
 435         free(pname);
 436 }
 437
 438 /*
 439  * Outputs an informative dump of the data in the MBR to stdout.
 440  */
 441 static void
 442 display_mbr(u_int8_t *mbr)
 443 {
 444     struct dos_partition *part;
 445     int i, version;
 446
 447     part = (struct dos_partition *)(mbr + DOSPARTOFF);
 448     printf(fmt0);
 449     for (i = 0; i < NDOSPART; i++)
 450         if (part[i].dp_typ)
 451             printf(fmt1, 1 + i, part[i].dp_flag,
 452                 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
 453                 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
 454                 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
 455                 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
 456                 part[i].dp_size);
 457     printf("\n");
 458     version = boot0version(mbr);
 459     printf("version=%d.%d  drive=0x%x  mask=0x%x  ticks=%u",
 460         version >> 8, version & 0xff, mbr[OFF_DRIVE],
 461         mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
 462     set_bell(mbr, 0, 1);
 463     printf("\noptions=");
 464     for (i = 0; i < nopt; i++) {
 465         if (i)
 466             printf(",");
 467         if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
 468             printf("no");
 469         printf("%s", opttbl[i].tok);
 470     }
 471     printf("\n");
 472     if (b0_ver == 2)
 473         printf("volume serial ID %02x%02x-%02x%02x\n",
 474                 mbr[OFF_SERIAL], mbr[OFF_SERIAL+1],
 475                 mbr[OFF_SERIAL+2], mbr[OFF_SERIAL+3]);
 476     printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
 477     if (mbr[OFF_OPT] < 4)
 478         printf("Slice %d", mbr[OFF_OPT] + 1);
 479     else if (mbr[OFF_OPT] == 4)
 480         printf("Drive 1");
 481     else
 482         printf("PXE");
 483     printf(")\n");
 484 }
 485
 486 /*
 487  * Return the boot0 version with the minor revision in the low byte, and
 488  * the major revision in the next higher byte.
 489  */
 490 static int
 491 boot0version(const u_int8_t *bs)
 492 {
 493     /* Check for old version, and return 0x100 if found. */
 494     int v = boot0bs(bs);
 495     if (v != 0)
 496         return v << 8;
 497
 498     /* We have a newer boot0, so extract the version number and return it. */
 499     return *(const int *)(bs + OFF_VERSION) & 0xffff;
 500 }
 501
 502 /* descriptor of a pattern to match.
 503  * Start from the first entry trying to match the chunk of bytes,
 504  * if you hit an entry with len=0 terminate the search and report
 505  * off as the version. Otherwise skip to the next block after len=0
 506  * An entry with len=0, off=0 is the end marker.
 507   */
 508 struct byte_pattern {
 509     unsigned off;
 510     unsigned len;
 511     u_int8_t *key;
 512 };
 513
 514 /*
 515  * Decide if we have valid boot0 boot code by looking for
 516  * characteristic byte sequences at fixed offsets.
 517  */
 518 static int
 519 boot0bs(const u_int8_t *bs)
 520 {
 521     /* the initial code sequence */
 522     static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
 523                              0x8e, 0xd0, 0xbc, 0x00, 0x7c };
 524     /* the drive id */
 525     static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '};
 526     static struct byte_pattern patterns[] = {
 527         {0x0,   sizeof(id0), id0},
 528         {0x1b2, sizeof(id1), id1},
 529         {1, 0, NULL},
 530         {0x0,   sizeof(id0), id0},      /* version with NT support */
 531         {0x1ae, sizeof(id1), id1},
 532         {2, 0, NULL},
 533         {0, 0, NULL},
 534     };
 535     struct byte_pattern *p = patterns;
 536
 537     for (;  p->off || p->len; p++) {
 538         if (p->len == 0)
 539             break;
 540         if (!memcmp(bs + p->off, p->key, p->len))       /* match */
 541             continue;
 542         while (p->len)  /* skip to next block */
 543             p++;
 544     }
 545     b0_ver = p->off;    /* XXX ugly side effect */
 546     return p->off;
 547 }
 548
 549 /*
 550  * Adjust "and" and "or" masks for a -o option argument.
 551  */
 552 static void
 553 stropt(const char *arg, int *xa, int *xo)
 554 {
 555     const char *q;
 556     char *s, *s1;
 557     int inv, i, x;
 558
 559     if (!(s = strdup(arg)))
 560         err(1, NULL);
 561     for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
 562         if ((inv = !strncmp(q, "no", 2)))
 563             q += 2;
 564         for (i = 0; i < nopt; i++)
 565             if (!strcmp(q, opttbl[i].tok))
 566                 break;
 567         if (i == nopt)
 568             errx(1, "%s: Unknown -o option", q);
 569         if (opttbl[i].def)
 570             inv ^= 1;
 571         x = 1 << (7 - i);
 572         if (inv)
 573             *xa &= ~x;
 574         else
 575             *xo |= x;
 576     }
 577     free(s);
 578 }
 579
 580 /*
 581  * Convert and check an option argument.
 582  */
 583 static int
 584 argtoi(const char *arg, int lo, int hi, int opt)
 585 {
 586     char *s;
 587     long x;
 588
 589     errno = 0;
 590     x = strtol(arg, &s, 0);
 591     if (errno || !*arg || *s || x < lo || x > hi)
 592         errx(1, "%s: Bad argument to -%c option", arg, opt);
 593     return x;
 594 }
 595
 596 /*
 597  * Display usage information.
 598  */
 599 static void
 600 usage(void)
 601 {
 602     fprintf(stderr, "%s\n%s\n",
 603     "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
 604     "                [-o options] [-s slice] [-t ticks] disk");
 605     exit(1);
 606 }