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 #ifndef lint 28 static const char rcsid[] = 29 "$FreeBSD$"; 30 #endif /* not lint */ 31 32 #include <sys/param.h> 33 #include <sys/disklabel.h> 34 #include <sys/diskmbr.h> 35 #include <sys/stat.h> 36 37 #include <err.h> 38 #include <errno.h> 39 #include <fcntl.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 */ 49 #define OFF_OPT 0x1b9 /* offset: default boot option */ 50 #define OFF_DRIVE 0x1ba /* offset: setdrv drive */ 51 #define OFF_FLAGS 0x1bb /* offset: option flags */ 52 #define OFF_TICKS 0x1bc /* offset: clock ticks */ 53 #define OFF_PTBL 0x1be /* offset: partition table */ 54 #define OFF_MAGIC 0x1fe /* offset: magic number */ 55 56 #define cv2(p) ((p)[0] | (p)[1] << 010) 57 58 #define mk2(p, x) \ 59 (p)[0] = (u_int8_t)(x), \ 60 (p)[1] = (u_int8_t)((x) >> 010) 61 62 static const struct { 63 const char *tok; 64 int def; 65 } opttbl[] = { 66 {"packet", 0}, 67 {"update", 1}, 68 {"setdrv", 0} 69 }; 70 static const int nopt = sizeof(opttbl) / sizeof(opttbl[0]); 71 72 static const char fmt0[] = "# flag start chs type" 73 " end chs offset size\n"; 74 75 static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x" 76 " %4u:%3u:%2u %10u %10u\n"; 77 78 static int read_mbr(const char *, u_int8_t **, int); 79 static void write_mbr(const char *, int, u_int8_t *, int); 80 static void display_mbr(u_int8_t *); 81 static int boot0version(const u_int8_t *); 82 static int boot0bs(const u_int8_t *); 83 static void stropt(const char *, int *, int *); 84 static char *mkrdev(const char *); 85 static int argtoi(const char *, int, int, int); 86 static void usage(void); 87 88 /* 89 * Boot manager installation/configuration utility. 90 */ 91 int 92 main(int argc, char *argv[]) 93 { 94 u_int8_t *mbr, *boot0; 95 int boot0_size, mbr_size; 96 const char *bpath, *fpath; 97 char *disk; 98 int B_flag, v_flag, o_flag; 99 int d_arg, m_arg, s_arg, t_arg; 100 int o_and, o_or; 101 int up, c; 102 103 bpath = "/boot/boot0"; 104 fpath = NULL; 105 B_flag = v_flag = o_flag = 0; 106 d_arg = m_arg = s_arg = t_arg = -1; 107 o_and = 0xff; 108 o_or = 0; 109 while ((c = getopt(argc, argv, "Bvb:d:f:m:o:s:t:")) != -1) 110 switch (c) { 111 case 'B': 112 B_flag = 1; 113 break; 114 case 'v': 115 v_flag = 1; 116 break; 117 case 'b': 118 bpath = optarg; 119 break; 120 case 'd': 121 d_arg = argtoi(optarg, 0, 0xff, 'd'); 122 break; 123 case 'f': 124 fpath = optarg; 125 break; 126 case 'm': 127 m_arg = argtoi(optarg, 0, 0xf, 'm'); 128 break; 129 case 'o': 130 stropt(optarg, &o_and, &o_or); 131 o_flag = 1; 132 break; 133 case 's': 134 s_arg = argtoi(optarg, 1, 5, 's'); 135 break; 136 case 't': 137 t_arg = argtoi(optarg, 1, 0xffff, 't'); 138 break; 139 default: 140 usage(); 141 } 142 argc -= optind; 143 argv += optind; 144 if (argc != 1) 145 usage(); 146 disk = mkrdev(*argv); 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, "%s", disk); 225 if ((n = read(fd, buf, MBRSIZE)) == -1) 226 err(1, "%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 return (mbr_size); 245 } 246 *mbr = malloc(sizeof(buf)); 247 memcpy(*mbr, buf, sizeof(buf)); 248 249 return sizeof(buf); 250 } 251 252 /* 253 * Write out the mbr to the specified file. 254 */ 255 static void 256 write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size) 257 { 258 int fd; 259 ssize_t n; 260 261 if ((fd = open(fname, O_WRONLY | flags, 0666)) == -1 || 262 (n = write(fd, mbr, mbr_size)) == -1 || close(fd)) 263 err(1, "%s", fname); 264 if (n != mbr_size) 265 errx(1, "%s: short write", fname); 266 } 267 268 /* 269 * Outputs an informative dump of the data in the MBR to stdout. 270 */ 271 static void 272 display_mbr(u_int8_t *mbr) 273 { 274 struct dos_partition *part; 275 int i, version; 276 277 part = (struct dos_partition *)(mbr + DOSPARTOFF); 278 printf(fmt0); 279 for (i = 0; i < NDOSPART; i++) 280 if (part[i].dp_typ) 281 printf(fmt1, 1 + i, part[i].dp_flag, 282 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2), 283 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ, 284 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2), 285 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start, 286 part[i].dp_size); 287 printf("\n"); 288 version = boot0version(mbr); 289 printf("version=%d.%d drive=0x%x mask=0x%x ticks=%u\noptions=", 290 version >> 8, version & 0xff, mbr[OFF_DRIVE], 291 mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS)); 292 for (i = 0; i < nopt; i++) { 293 if (i) 294 printf(","); 295 if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def) 296 printf("no"); 297 printf("%s", opttbl[i].tok); 298 } 299 printf("\n"); 300 printf("default_selection=F%d (", mbr[OFF_OPT] + 1); 301 if (mbr[OFF_OPT] < 4) 302 printf("Slice %d", mbr[OFF_OPT] + 1); 303 else 304 printf("Drive 1"); 305 printf(")\n"); 306 } 307 308 /* 309 * Return the boot0 version with the minor revision in the low byte, and 310 * the major revision in the next higher byte. 311 */ 312 static int 313 boot0version(const u_int8_t *bs) 314 { 315 static u_int8_t idold[] = {0xfe, 0x45, 0xf2, 0xe9, 0x00, 0x8a}; 316 317 /* Check for old version, and return 0x100 if found. */ 318 if (memcmp(bs + 0x1c, idold, sizeof(idold)) == 0) 319 return 0x100; 320 321 /* We have a newer boot0, so extract the version number and return it. */ 322 return *(const int *)(bs + OFF_VERSION) & 0xffff; 323 } 324 325 /* 326 * Decide if we have valid boot0 boot code by looking for 327 * characteristic byte sequences at fixed offsets. 328 */ 329 static int 330 boot0bs(const u_int8_t *bs) 331 { 332 static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8, 333 0x8e, 0xd0, 0xbc, 0x00, 0x7c }; 334 static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '}; 335 static struct { 336 unsigned off; 337 unsigned len; 338 u_int8_t *key; 339 } ident[2] = { 340 {0x0, sizeof(id0), id0}, 341 {0x1b2, sizeof(id1), id1} 342 }; 343 unsigned int i; 344 345 for (i = 0; i < sizeof(ident) / sizeof(ident[0]); i++) 346 if (memcmp(bs + ident[i].off, ident[i].key, ident[i].len)) 347 return 0; 348 return 1; 349 }; 350 351 /* 352 * Adjust "and" and "or" masks for a -o option argument. 353 */ 354 static void 355 stropt(const char *arg, int *xa, int *xo) 356 { 357 const char *q; 358 char *s, *s1; 359 int inv, i, x; 360 361 if (!(s = strdup(arg))) 362 err(1, NULL); 363 for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) { 364 if ((inv = !strncmp(q, "no", 2))) 365 q += 2; 366 for (i = 0; i < nopt; i++) 367 if (!strcmp(q, opttbl[i].tok)) 368 break; 369 if (i == nopt) 370 errx(1, "%s: Unknown -o option", q); 371 if (opttbl[i].def) 372 inv ^= 1; 373 x = 1 << (7 - i); 374 if (inv) 375 *xa &= ~x; 376 else 377 *xo |= x; 378 } 379 free(s); 380 } 381 382 /* 383 * Produce a device path for a "canonical" name, where appropriate. 384 */ 385 static char * 386 mkrdev(const char *fname) 387 { 388 char buf[MAXPATHLEN]; 389 char *s; 390 391 if (!strchr(fname, '/')) { 392 snprintf(buf, sizeof(buf), "%s%s", _PATH_DEV, fname); 393 s = strdup(buf); 394 } else 395 s = strdup(fname); 396 397 if (s == NULL) 398 errx(1, "No more memory"); 399 return s; 400 } 401 402 /* 403 * Convert and check an option argument. 404 */ 405 static int 406 argtoi(const char *arg, int lo, int hi, int opt) 407 { 408 char *s; 409 long x; 410 411 errno = 0; 412 x = strtol(arg, &s, 0); 413 if (errno || !*arg || *s || x < lo || x > hi) 414 errx(1, "%s: Bad argument to -%c option", arg, opt); 415 return x; 416 } 417 418 /* 419 * Display usage information. 420 */ 421 static void 422 usage(void) 423 { 424 fprintf(stderr, "%s\n%s\n", 425 "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]", 426 " [-o options] [-s slice] [-t ticks] disk"); 427 exit(1); 428 } 429