usr.sbin/boot0cfg/boot0cfg.c

   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  * $DragonFly: src/usr.sbin/boot0cfg/boot0cfg.c,v 1.5 2007/05/20 23:21:37 dillon Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/diskmbr.h>
  32 #include <sys/stat.h>
  33
  34 #include <err.h>
  35 #include <errno.h>
  36 #include <fcntl.h>
  37 #include <paths.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <unistd.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 #define OFF_MAGIC       0x1fe   /* offset: magic number */
  52
  53 #define cv2(p)  ((p)[0] | (p)[1] << 010)
  54
  55 #define mk2(p, x)                               \
  56     (p)[0] = (u_int8_t)(x),                     \
  57     (p)[1] = (u_int8_t)((x) >> 010)
  58
  59 static const struct {
  60     const char *tok;
  61     int def;
  62 } opttbl[] = {
  63     {"packet", 0},
  64     {"update", 1},
  65     {"setdrv", 0}
  66 };
  67 static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]);
  68
  69 static const char fmt0[] = "#   flag     start chs   type"
  70     "       end chs       offset         size\n";
  71
  72 static const char fmt1[] = "%d   0x%02x   %4u:%3u:%2u   0x%02x"
  73     "   %4u:%3u:%2u   %10u   %10u\n";
  74
  75 static int read_mbr(const char *, u_int8_t **, int);
  76 static void write_mbr(const char *, int, u_int8_t *, int);
  77 static void display_mbr(u_int8_t *);
  78 static int boot0version(const u_int8_t *);
  79 static int boot0bs(const u_int8_t *);
  80 static void stropt(const char *, int *, int *);
  81 static char *mkrdev(const char *);
  82 static int argtoi(const char *, int, int, int);
  83 static void usage(void);
  84
  85 /*
  86  * Boot manager installation/configuration utility.
  87  */
  88 int
  89 main(int argc, char *argv[])
  90 {
  91     u_int8_t *mbr, *boot0;
  92     int boot0_size, mbr_size;
  93     const char *bpath, *fpath;
  94     char *disk;
  95     int B_flag, v_flag, o_flag;
  96     int d_arg, m_arg, s_arg, t_arg;
  97     int o_and, o_or;
  98     int up, c;
  99
 100     bpath = "/boot/boot0";
 101     fpath = NULL;
 102     B_flag = v_flag = o_flag = 0;
 103     d_arg = m_arg = s_arg = t_arg = -1;
 104     o_and = 0xff;
 105     o_or = 0;
 106     while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1)
 107         switch (c) {
 108         case 'B':
 109             B_flag = 1;
 110             break;
 111         case 'v':
 112             v_flag = 1;
 113             break;
 114         case 'b':
 115             bpath = optarg;
 116             break;
 117         case 'd':
 118             d_arg = argtoi(optarg, 0, 0xff, 'd');
 119             break;
 120         case 'f':
 121             fpath = optarg;
 122             break;
 123         case 'm':
 124             m_arg = argtoi(optarg, 0, 0xf, 'm');
 125             break;
 126         case 'o':
 127             stropt(optarg, &o_and, &o_or);
 128             o_flag = 1;
 129             break;
 130         case 's':
 131             s_arg = argtoi(optarg, 1, 5, 's');
 132             break;
 133         case 't':
 134             t_arg = argtoi(optarg, 1, 0xffff, 't');
 135             break;
 136         default:
 137             usage();
 138         }
 139     argc -= optind;
 140     argv += optind;
 141     if (argc != 1)
 142         usage();
 143     disk = mkrdev(*argv);
 144     up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1
 145         || t_arg != -1;
 146
 147     /* open the disk and read in the existing mbr */
 148     mbr_size = read_mbr(disk, &mbr, !B_flag);
 149
 150     /* save the existing MBR if we are asked to do so */
 151     if (fpath)
 152         write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size);
 153
 154     /*
 155      * If we are installing the boot loader, read it from disk and copy the
 156      * slice table over from the existing MBR.  If not, then point boot0
 157      * back at the MBR we just read in.  After this, boot0 is the data to
 158      * write back to disk if we are going to do a write.
 159      */
 160     if (B_flag) {
 161         boot0_size = read_mbr(bpath, &boot0, 1);
 162         memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL,
 163             sizeof(struct dos_partition) * NDOSPART);
 164     } else {
 165         boot0 = mbr;
 166         boot0_size = mbr_size;
 167     }
 168
 169     /* set the drive */
 170     if (d_arg != -1)
 171         boot0[OFF_DRIVE] = d_arg;
 172
 173     /* set various flags */
 174     if (m_arg != -1) {
 175         boot0[OFF_FLAGS] &= 0xf0;
 176         boot0[OFF_FLAGS] |= m_arg;
 177     }
 178     if (o_flag) {
 179         boot0[OFF_FLAGS] &= o_and;
 180         boot0[OFF_FLAGS] |= o_or;
 181     }
 182
 183     /* set the default boot selection */
 184     if (s_arg != -1)
 185         boot0[OFF_OPT] = s_arg - 1;
 186
 187     /* set the timeout */
 188     if (t_arg != -1)
 189         mk2(boot0 + OFF_TICKS, t_arg);
 190
 191     /* write the MBR back to disk */
 192     if (up)
 193         write_mbr(disk, 0, boot0, boot0_size);
 194
 195     /* display the MBR */
 196     if (v_flag)
 197         display_mbr(boot0);
 198
 199     /* clean up */
 200     if (mbr != boot0)
 201         free(boot0);
 202     free(mbr);
 203     free(disk);
 204
 205     return 0;
 206 }
 207
 208 /*
 209  * Read in the MBR of the disk.  If it is boot0, then use the version to
 210  * read in all of it if necessary.  Use pointers to return a malloc'd
 211  * buffer containing the MBR and then return its size.
 212  */
 213 static int
 214 read_mbr(const char *disk, u_int8_t **mbr, int check_version)
 215 {
 216     u_int8_t buf[MBRSIZE];
 217     int mbr_size, fd;
 218     ssize_t n;
 219
 220     if ((fd = open(disk, O_RDONLY)) == -1)
 221         err(1, "%s", disk);
 222     if ((n = read(fd, buf, MBRSIZE)) == -1)
 223         err(1, "%s", disk);
 224     if (n != MBRSIZE)
 225         errx(1, "%s: short read", disk);
 226     if (cv2(buf + OFF_MAGIC) != 0xaa55)
 227         errx(1, "%s: bad magic", disk);
 228
 229     if (!boot0bs(buf)) {
 230         if (check_version)
 231             errx(1, "%s: unknown or incompatible boot code", disk);
 232     } else if (boot0version(buf) == 0x101) {
 233         mbr_size = 1024;
 234         if ((*mbr = malloc(mbr_size)) == NULL)
 235             errx(1, "%s: unable to allocate read buffer", disk);
 236         if (lseek(fd, 0, SEEK_SET) == -1 ||
 237             (n = read(fd, *mbr, mbr_size)) == -1)
 238             err(1, "%s", disk);
 239         if (n != mbr_size)
 240             errx(1, "%s: short read", disk);
 241         return (mbr_size);
 242     }
 243     *mbr = malloc(sizeof(buf));
 244     memcpy(*mbr, buf, sizeof(buf));
 245
 246     return sizeof(buf);
 247 }
 248
 249 /*
 250  * Write out the mbr to the specified file.
 251  */
 252 static void
 253 write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size)
 254 {
 255     int fd;
 256     ssize_t n;
 257
 258     if ((fd = open(fname, O_WRONLY | flags, 0666)) == -1 ||
 259         (n = write(fd, mbr, mbr_size)) == -1 || close(fd))
 260         err(1, "%s", fname);
 261     if (n != mbr_size)
 262         errx(1, "%s: short write", fname);
 263 }
 264
 265 /*
 266  * Outputs an informative dump of the data in the MBR to stdout.
 267  */
 268 static void
 269 display_mbr(u_int8_t *mbr)
 270 {
 271     struct dos_partition *part;
 272     int i, version;
 273
 274     part = (struct dos_partition *)(mbr + DOSPARTOFF);
 275     printf(fmt0);
 276     for (i = 0; i < NDOSPART; i++)
 277         if (part[i].dp_typ)
 278             printf(fmt1, 1 + i, part[i].dp_flag,
 279                 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2),
 280                 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ,
 281                 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2),
 282                 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start,
 283                 part[i].dp_size);
 284     printf("\n");
 285     version = boot0version(mbr);
 286     printf("version=%d.%d  drive=0x%x  mask=0x%x  ticks=%u\noptions=",
 287         version >> 8, version & 0xff, mbr[OFF_DRIVE],
 288         mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS));
 289     for (i = 0; i < nopt; i++) {
 290         if (i)
 291             printf(",");
 292         if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def)
 293             printf("no");
 294         printf("%s", opttbl[i].tok);
 295     }
 296     printf("\n");
 297     printf("default_selection=F%d (", mbr[OFF_OPT] + 1);
 298     if (mbr[OFF_OPT] < 4)
 299         printf("Slice %d", mbr[OFF_OPT] + 1);
 300     else
 301         printf("Drive 1");
 302     printf(")\n");
 303 }
 304
 305 /*
 306  * Return the boot0 version with the minor revision in the low byte, and
 307  * the major revision in the next higher byte.
 308  */
 309 static int
 310 boot0version(const u_int8_t *bs)
 311 {
 312     static u_int8_t idold[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a};
 313
 314     /* Check for old version, and return 0x100 if found. */
 315     if (memcmp(bs + 0x1c, idold, sizeof(idold)) == 0)
 316         return 0x100;
 317
 318     /* We have a newer boot0, so extract the version number and return it. */
 319     return *(const int *)(bs + OFF_VERSION) & 0xffff;
 320 }
 321
 322 /*
 323  * Decide if we have valid boot0 boot code by looking for
 324  * characteristic byte sequences at fixed offsets.
 325  */
 326 static int
 327 boot0bs(const u_int8_t *bs)
 328 {
 329     static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8,
 330                              0x8e, 0xd0, 0xbc, 0x00, 0x7c };
 331     static u_int8_t id1[] = {0xfc, 0xb8, 0x00, 0x09, 0x8e, 0xc0, 0x8e,
 332                              0xd0, 0xbc, 0x00, 0x10 ,0x31 };
 333     static u_int8_t id2[] = {'D', 'r', 'i', 'v', 'e', ' '};
 334     static struct {
 335         unsigned off;
 336         unsigned len;
 337         u_int8_t *key;
 338     } ident[] = {
 339         {0x0,   sizeof(id0), id0},
 340         {0x0,   sizeof(id1), id1},
 341         {0x1b2, sizeof(id2), id2}
 342     };
 343     unsigned int i;
 344     int count = 0;
 345
 346     for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++) {
 347         if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len) == 0)
 348             ++count;
 349     }
 350     if (count >= 2)
 351         return 1;
 352     return 0;
 353 };
 354
 355 /*
 356  * Adjust "and" and "or" masks for a -o option argument.
 357  */
 358 static void
 359 stropt(const char *arg, int *xa, int *xo)
 360 {
 361     const char *q;
 362     char *s, *s1;
 363     int inv, i, x;
 364
 365     if (!(s = strdup(arg)))
 366         err(1, NULL);
 367     for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) {
 368         if ((inv = !strncmp(q, "no", 2)))
 369             q += 2;
 370         for (i = 0; i < nopt; i++)
 371             if (!strcmp(q, opttbl[i].tok))
 372                 break;
 373         if (i == nopt)
 374             errx(1, "%s: Unknown -o option", q);
 375         if (opttbl[i].def)
 376             inv ^= 1;
 377         x = 1 << (7 - i);
 378         if (inv)
 379             *xa &= ~x;
 380         else
 381             *xo |= x;
 382     }
 383     free(s);
 384 }
 385
 386 /*
 387  * Produce a device path for a "canonical" name, where appropriate.
 388  */
 389 static char *
 390 mkrdev(const char *fname)
 391 {
 392     char buf[MAXPATHLEN];
 393     char *s;
 394
 395     if (!strchr(fname, '/')) {
 396         snprintf(buf, sizeof(buf), "%s%s", _PATH_DEV, fname);
 397         s = strdup(buf);
 398     } else
 399         s = strdup(fname);
 400
 401     if (s == NULL)
 402         errx(1, "No more memory");
 403     return s;
 404 }
 405
 406 /*
 407  * Convert and check an option argument.
 408  */
 409 static int
 410 argtoi(const char *arg, int lo, int hi, int opt)
 411 {
 412     char *s;
 413     long x;
 414
 415     errno = 0;
 416     x = strtol(arg, &s, 0);
 417     if (errno || !*arg || *s || x < lo || x > hi)
 418         errx(1, "%s: Bad argument to -%c option", arg, opt);
 419     return x;
 420 }
 421
 422 /*
 423  * Display usage information.
 424  */
 425 static void
 426 usage(void)
 427 {
 428     fprintf(stderr, "%s\n%s\n",
 429     "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]",
 430     "                [-o options] [-s slice] [-t ticks] disk");
 431     exit(1);
 432 }