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 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 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 <paths.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 #define MBRSIZE 512 /* master boot record size */ 45 46 #define OFF_VERSION 0x1b0 /* offset: version number */ 47 #define OFF_OPT 0x1b9 /* offset: default boot option */ 48 #define OFF_DRIVE 0x1ba /* offset: setdrv drive */ 49 #define OFF_FLAGS 0x1bb /* offset: option flags */ 50 #define OFF_TICKS 0x1bc /* offset: clock ticks */ 51 #define OFF_PTBL 0x1be /* offset: partition table */ 52 #define OFF_MAGIC 0x1fe /* offset: magic number */ 53 54 #define cv2(p) ((p)[0] | (p)[1] << 010) 55 56 #define mk2(p, x) \ 57 (p)[0] = (u_int8_t)(x), \ 58 (p)[1] = (u_int8_t)((x) >> 010) 59 60 static const struct { 61 const char *tok; 62 int def; 63 } opttbl[] = { 64 {"packet", 0}, 65 {"update", 1}, 66 {"setdrv", 0} 67 }; 68 static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]); 69 70 static const char fmt0[] = "# flag start chs type" 71 " end chs offset size\n"; 72 73 static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x" 74 " %4u:%3u:%2u %10u %10u\n"; 75 76 static int read_mbr(const char *, u_int8_t **, int); 77 static void write_mbr(const char *, int, u_int8_t *, int); 78 static void display_mbr(u_int8_t *); 79 static int boot0version(const u_int8_t *); 80 static int boot0bs(const u_int8_t *); 81 static void stropt(const char *, int *, int *); 82 static char *mkrdev(const char *); 83 static int argtoi(const char *, int, int, int); 84 static void usage(void); 85 86 /* 87 * Boot manager installation/configuration utility. 88 */ 89 int 90 main(int argc, char *argv[]) 91 { 92 u_int8_t *mbr, *boot0; 93 int boot0_size, mbr_size; 94 const char *bpath, *fpath; 95 char *disk; 96 int B_flag, v_flag, o_flag; 97 int d_arg, m_arg, s_arg, t_arg; 98 int o_and, o_or; 99 int up, c; 100 101 bpath = "/boot/boot0"; 102 fpath = NULL; 103 B_flag = v_flag = o_flag = 0; 104 d_arg = m_arg = s_arg = t_arg = -1; 105 o_and = 0xff; 106 o_or = 0; 107 while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1) 108 switch (c) { 109 case 'B': 110 B_flag = 1; 111 break; 112 case 'v': 113 v_flag = 1; 114 break; 115 case 'b': 116 bpath = optarg; 117 break; 118 case 'd': 119 d_arg = argtoi(optarg, 0, 0xff, 'd'); 120 break; 121 case 'f': 122 fpath = optarg; 123 break; 124 case 'm': 125 m_arg = argtoi(optarg, 0, 0xf, 'm'); 126 break; 127 case 'o': 128 stropt(optarg, &o_and, &o_or); 129 o_flag = 1; 130 break; 131 case 's': 132 s_arg = argtoi(optarg, 1, 5, 's'); 133 break; 134 case 't': 135 t_arg = argtoi(optarg, 1, 0xffff, 't'); 136 break; 137 default: 138 usage(); 139 } 140 argc -= optind; 141 argv += optind; 142 if (argc != 1) 143 usage(); 144 disk = mkrdev(*argv); 145 up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1 146 || t_arg != -1; 147 148 /* open the disk and read in the existing mbr */ 149 mbr_size = read_mbr(disk, &mbr, !B_flag); 150 151 /* save the existing MBR if we are asked to do so */ 152 if (fpath) 153 write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size); 154 155 /* 156 * If we are installing the boot loader, read it from disk and copy the 157 * slice table over from the existing MBR. If not, then point boot0 158 * back at the MBR we just read in. After this, boot0 is the data to 159 * write back to disk if we are going to do a write. 160 */ 161 if (B_flag) { 162 boot0_size = read_mbr(bpath, &boot0, 1); 163 memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL, 164 sizeof(struct dos_partition) * NDOSPART); 165 } else { 166 boot0 = mbr; 167 boot0_size = mbr_size; 168 } 169 170 /* set the drive */ 171 if (d_arg != -1) 172 boot0[OFF_DRIVE] = d_arg; 173 174 /* set various flags */ 175 if (m_arg != -1) { 176 boot0[OFF_FLAGS] &= 0xf0; 177 boot0[OFF_FLAGS] |= m_arg; 178 } 179 if (o_flag) { 180 boot0[OFF_FLAGS] &= o_and; 181 boot0[OFF_FLAGS] |= o_or; 182 } 183 184 /* set the default boot selection */ 185 if (s_arg != -1) 186 boot0[OFF_OPT] = s_arg - 1; 187 188 /* set the timeout */ 189 if (t_arg != -1) 190 mk2(boot0 + OFF_TICKS, t_arg); 191 192 /* write the MBR back to disk */ 193 if (up) 194 write_mbr(disk, 0, boot0, boot0_size); 195 196 /* display the MBR */ 197 if (v_flag) 198 display_mbr(boot0); 199 200 /* clean up */ 201 if (mbr != boot0) 202 free(boot0); 203 free(mbr); 204 free(disk); 205 206 return 0; 207 } 208 209 /* 210 * Read in the MBR of the disk. If it is boot0, then use the version to 211 * read in all of it if necessary. Use pointers to return a malloc'd 212 * buffer containing the MBR and then return its size. 213 */ 214 static int 215 read_mbr(const char *disk, u_int8_t **mbr, int check_version) 216 { 217 u_int8_t buf[MBRSIZE]; 218 int mbr_size, fd; 219 ssize_t n; 220 221 if ((fd = open(disk, O_RDONLY)) == -1) 222 err(1, "open %s", disk); 223 if ((n = read(fd, buf, MBRSIZE)) == -1) 224 err(1, "read %s", disk); 225 if (n != MBRSIZE) 226 errx(1, "%s: short read", disk); 227 if (cv2(buf + OFF_MAGIC) != 0xaa55) 228 errx(1, "%s: bad magic", disk); 229 230 if (!boot0bs(buf)) { 231 if (check_version) 232 errx(1, "%s: unknown or incompatible boot code", disk); 233 } else if (boot0version(buf) == 0x101) { 234 mbr_size = 1024; 235 if ((*mbr = malloc(mbr_size)) == NULL) 236 errx(1, "%s: unable to allocate read buffer", disk); 237 if (lseek(fd, 0, SEEK_SET) == -1 || 238 (n = read(fd, *mbr, mbr_size)) == -1) 239 err(1, "%s", disk); 240 if (n != mbr_size) 241 errx(1, "%s: short read", disk); 242 return (mbr_size); 243 } 244 *mbr = malloc(sizeof(buf)); 245 memcpy(*mbr, buf, sizeof(buf)); 246 247 return sizeof(buf); 248 } 249 250 /* 251 * Write out the mbr to the specified file. 252 */ 253 static void 254 write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size) 255 { 256 int fd, p; 257 ssize_t n; 258 char *s; 259 260 fd = open(fname, O_WRONLY | flags, 0666); 261 if (fd != -1) { 262 n = write(fd, mbr, mbr_size); 263 close(fd); 264 if (n != mbr_size) 265 errx(1, "%s: short write", fname); 266 return; 267 } 268 if (flags != 0) 269 err(1, "%s", fname); 270 #ifdef DIOCSMBR 271 for (p = 1; p < 5; p++) { 272 asprintf(&s, "%ss%d", fname, p); 273 fd = open(s, O_RDWR); 274 if (fd < 0) { 275 free(s); 276 continue; 277 } 278 n = ioctl(fd, DIOCSMBR, (mbr)); 279 if (n != 0) 280 err(1, "%s: ioctl DIOCSMBR", fname); 281 close(fd); 282 free(s); 283 return; 284 } 285 #endif 286 err(1, "write_mbr: %s", fname); 287 } 288 289 /* 290 * Outputs an informative dump of the data in the MBR to stdout. 291 */ 292 static void 293 display_mbr(u_int8_t *mbr) 294 { 295 struct dos_partition *part; 296 int i, version; 297 298 part = (struct dos_partition *)(mbr + DOSPARTOFF); 299 printf(fmt0); 300 for (i = 0; i < NDOSPART; i++) 301 if (part[i].dp_typ) 302 printf(fmt1, 1 + i, part[i].dp_flag, 303 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2), 304 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ, 305 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2), 306 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start, 307 part[i].dp_size); 308 printf("\n"); 309 version = boot0version(mbr); 310 printf("version=%d.%d drive=0x%x mask=0x%x ticks=%u\noptions=", 311 version >> 8, version & 0xff, mbr[OFF_DRIVE], 312 mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS)); 313 for (i = 0; i < nopt; i++) { 314 if (i) 315 printf(","); 316 if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def) 317 printf("no"); 318 printf("%s", opttbl[i].tok); 319 } 320 printf("\n"); 321 printf("default_selection=F%d (", mbr[OFF_OPT] + 1); 322 if (mbr[OFF_OPT] < 4) 323 printf("Slice %d", mbr[OFF_OPT] + 1); 324 else 325 printf("Drive 1"); 326 printf(")\n"); 327 } 328 329 /* 330 * Return the boot0 version with the minor revision in the low byte, and 331 * the major revision in the next higher byte. 332 */ 333 static int 334 boot0version(const u_int8_t *bs) 335 { 336 static u_int8_t idold[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a}; 337 338 /* Check for old version, and return 0x100 if found. */ 339 if (memcmp(bs + 0x1c, idold, sizeof(idold)) == 0) 340 return 0x100; 341 342 /* We have a newer boot0, so extract the version number and return it. */ 343 return *(const int *)(bs + OFF_VERSION) & 0xffff; 344 } 345 346 /* 347 * Decide if we have valid boot0 boot code by looking for 348 * characteristic byte sequences at fixed offsets. 349 */ 350 static int 351 boot0bs(const u_int8_t *bs) 352 { 353 static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8, 354 0x8e, 0xd0, 0xbc, 0x00, 0x7c }; 355 static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '}; 356 static struct { 357 unsigned off; 358 unsigned len; 359 u_int8_t *key; 360 } ident[2] = { 361 {0x0, sizeof(id0), id0}, 362 {0x1b2, sizeof(id1), id1} 363 }; 364 unsigned int i; 365 366 for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++) 367 if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len)) 368 return 0; 369 return 1; 370 } 371 372 /* 373 * Adjust "and" and "or" masks for a -o option argument. 374 */ 375 static void 376 stropt(const char *arg, int *xa, int *xo) 377 { 378 const char *q; 379 char *s, *s1; 380 int inv, i, x; 381 382 if (!(s = strdup(arg))) 383 err(1, NULL); 384 for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) { 385 if ((inv = !strncmp(q, "no", 2))) 386 q += 2; 387 for (i = 0; i < nopt; i++) 388 if (!strcmp(q, opttbl[i].tok)) 389 break; 390 if (i == nopt) 391 errx(1, "%s: Unknown -o option", q); 392 if (opttbl[i].def) 393 inv ^= 1; 394 x = 1 << (7 - i); 395 if (inv) 396 *xa &= ~x; 397 else 398 *xo |= x; 399 } 400 free(s); 401 } 402 403 /* 404 * Produce a device path for a "canonical" name, where appropriate. 405 */ 406 static char * 407 mkrdev(const char *fname) 408 { 409 char buf[MAXPATHLEN]; 410 char *s; 411 412 if (!strchr(fname, '/')) { 413 snprintf(buf, sizeof(buf), "%s%s", _PATH_DEV, fname); 414 s = strdup(buf); 415 } else 416 s = strdup(fname); 417 418 if (s == NULL) 419 errx(1, "No more memory"); 420 return s; 421 } 422 423 /* 424 * Convert and check an option argument. 425 */ 426 static int 427 argtoi(const char *arg, int lo, int hi, int opt) 428 { 429 char *s; 430 long x; 431 432 errno = 0; 433 x = strtol(arg, &s, 0); 434 if (errno || !*arg || *s || x < lo || x > hi) 435 errx(1, "%s: Bad argument to -%c option", arg, opt); 436 return x; 437 } 438 439 /* 440 * Display usage information. 441 */ 442 static void 443 usage(void) 444 { 445 fprintf(stderr, "%s\n%s\n", 446 "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]", 447 " [-o options] [-s slice] [-t ticks] disk"); 448 exit(1); 449 } 450