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