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 = NELEM(opttbl); 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 < NELEM(ident); 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 } 425