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