boot0cfg.c revision 330449
1/* 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2008 Luigi Rizzo 5 * Copyright (c) 1999 Robert Nordier 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 22 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 23 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 24 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 26 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 27 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30#include <sys/cdefs.h> 31__FBSDID("$FreeBSD: stable/11/usr.sbin/boot0cfg/boot0cfg.c 330449 2018-03-05 07:26:05Z eadler $"); 32 33#include <sys/param.h> 34#include <sys/disklabel.h> 35#include <sys/diskmbr.h> 36#include <sys/stat.h> 37 38#include <err.h> 39#include <errno.h> 40#include <fcntl.h> 41#include <libgeom.h> 42#include <paths.h> 43#include <stdio.h> 44#include <stdlib.h> 45#include <string.h> 46#include <unistd.h> 47 48#define MBRSIZE 512 /* master boot record size */ 49 50#define OFF_VERSION 0x1b0 /* offset: version number, only boot0version */ 51#define OFF_SERIAL 0x1b8 /* offset: volume serial number */ 52#define OFF_PTBL 0x1be /* offset: partition table */ 53#define OFF_MAGIC 0x1fe /* offset: magic number */ 54/* 55 * Offsets to the parameters of the 512-byte boot block. 56 * For historical reasons they are set as macros 57 */ 58struct opt_offsets { 59 int opt; 60 int drive; 61 int flags; 62 int ticks; 63}; 64 65static struct opt_offsets b0_ofs[] = { 66 { 0x0, 0x0, 0x0, 0x0 }, /* no boot block */ 67 { 0x1b9, 0x1ba, 0x1bb, 0x1bc }, /* original block */ 68 { 0x1b5, 0x1b6, 0x1b7, 0x1bc }, /* NT_SERIAL block */ 69}; 70 71static int b0_ver; /* boot block version set by boot0bs */ 72 73#define OFF_OPT (b0_ofs[b0_ver].opt) /* default boot option */ 74#define OFF_DRIVE (b0_ofs[b0_ver].drive) /* setdrv drive */ 75#define OFF_FLAGS (b0_ofs[b0_ver].flags) /* option flags */ 76#define OFF_TICKS (b0_ofs[b0_ver].ticks) /* clock ticks */ 77 78 79#define cv2(p) ((p)[0] | (p)[1] << 010) 80 81#define mk2(p, x) \ 82 (p)[0] = (u_int8_t)(x), \ 83 (p)[1] = (u_int8_t)((x) >> 010) 84 85static const struct { 86 const char *tok; 87 int def; 88} opttbl[] = { 89 {"packet", 0}, 90 {"update", 1}, 91 {"setdrv", 0} 92}; 93static const int nopt = nitems(opttbl); 94 95static const char fmt0[] = "# flag start chs type" 96 " end chs offset size\n"; 97 98static const char fmt1[] = "%d 0x%02x %4u:%3u:%2u 0x%02x" 99 " %4u:%3u:%2u %10u %10u\n"; 100 101static int geom_class_available(const char *); 102static int read_mbr(const char *, u_int8_t **, int); 103static void write_mbr(const char *, int, u_int8_t *, int); 104static void display_mbr(u_int8_t *); 105static int boot0version(const u_int8_t *); 106static int boot0bs(const u_int8_t *); 107static void stropt(const char *, int *, int *); 108static int argtoi(const char *, int, int, int); 109static int set_bell(u_int8_t *, int, int); 110static void usage(void); 111 112static unsigned vol_id[5]; /* 4 plus 1 for flag */ 113 114static int v_flag; 115/* 116 * Boot manager installation/configuration utility. 117 */ 118int 119main(int argc, char *argv[]) 120{ 121 u_int8_t *mbr, *boot0; 122 int boot0_size, mbr_size; 123 const char *bpath, *fpath; 124 char *disk; 125 int B_flag, o_flag; 126 int d_arg, m_arg, s_arg, t_arg; 127 int o_and, o_or, o_e = -1; 128 int up, c; 129 130 bpath = "/boot/boot0"; 131 fpath = NULL; 132 B_flag = v_flag = o_flag = 0; 133 d_arg = m_arg = s_arg = t_arg = -1; 134 o_and = 0xff; 135 o_or = 0; 136 while ((c = getopt(argc, argv, "Bvb:d:e:f:i:m:o:s:t:")) != -1) 137 switch (c) { 138 case 'B': 139 B_flag = 1; 140 break; 141 case 'v': 142 v_flag = 1; 143 break; 144 case 'b': 145 bpath = optarg; 146 break; 147 case 'd': 148 d_arg = argtoi(optarg, 0, 0xff, 'd'); 149 break; 150 case 'e': 151 if (optarg[0] == '0' && optarg[1] == 'x') 152 sscanf(optarg, "0x%02x", &o_e); 153 else 154 o_e = optarg[0]; 155 break; 156 case 'f': 157 fpath = optarg; 158 break; 159 case 'i': 160 if (sscanf(optarg, "%02x%02x-%02x%02x", 161 vol_id, vol_id+1, vol_id+2, vol_id+3) == 4) 162 vol_id[4] = 1; 163 else 164 errx(1, "bad argument %s", optarg); 165 break; 166 case 'm': 167 m_arg = argtoi(optarg, 0, 0xf, 'm'); 168 break; 169 case 'o': 170 stropt(optarg, &o_and, &o_or); 171 o_flag = 1; 172 break; 173 case 's': 174 if (strcasecmp(optarg, "pxe") == 0) 175 s_arg = 6; 176 else 177 s_arg = argtoi(optarg, 1, 6, 's'); 178 break; 179 case 't': 180 t_arg = argtoi(optarg, 1, 0xffff, 't'); 181 break; 182 default: 183 usage(); 184 } 185 argc -= optind; 186 argv += optind; 187 if (argc != 1) 188 usage(); 189 disk = g_device_path(*argv); 190 if (disk == NULL) 191 errx(1, "Unable to get providername for %s\n", *argv); 192 up = B_flag || d_arg != -1 || m_arg != -1 || o_flag || s_arg != -1 193 || t_arg != -1; 194 195 /* open the disk and read in the existing mbr. Either here or 196 * when reading the block from disk, we do check for the version 197 * and abort if a suitable block is not found. 198 */ 199 mbr_size = read_mbr(disk, &mbr, !B_flag); 200 201 /* save the existing MBR if we are asked to do so */ 202 if (fpath) 203 write_mbr(fpath, O_CREAT | O_TRUNC, mbr, mbr_size); 204 205 /* 206 * If we are installing the boot loader, read it from disk and copy the 207 * slice table over from the existing MBR. If not, then point boot0 208 * back at the MBR we just read in. After this, boot0 is the data to 209 * write back to disk if we are going to do a write. 210 */ 211 if (B_flag) { 212 boot0_size = read_mbr(bpath, &boot0, 1); 213 memcpy(boot0 + OFF_PTBL, mbr + OFF_PTBL, 214 sizeof(struct dos_partition) * NDOSPART); 215 if (b0_ver == 2) /* volume serial number support */ 216 memcpy(boot0 + OFF_SERIAL, mbr + OFF_SERIAL, 4); 217 } else { 218 boot0 = mbr; 219 boot0_size = mbr_size; 220 } 221 222 /* set the drive */ 223 if (d_arg != -1) 224 boot0[OFF_DRIVE] = d_arg; 225 226 /* set various flags */ 227 if (m_arg != -1) { 228 boot0[OFF_FLAGS] &= 0xf0; 229 boot0[OFF_FLAGS] |= m_arg; 230 } 231 if (o_flag) { 232 boot0[OFF_FLAGS] &= o_and; 233 boot0[OFF_FLAGS] |= o_or; 234 } 235 236 /* set the default boot selection */ 237 if (s_arg != -1) 238 boot0[OFF_OPT] = s_arg - 1; 239 240 /* set the timeout */ 241 if (t_arg != -1) 242 mk2(boot0 + OFF_TICKS, t_arg); 243 244 /* set the bell char */ 245 if (o_e != -1 && set_bell(boot0, o_e, 0) != -1) 246 up = 1; 247 248 if (vol_id[4]) { 249 if (b0_ver != 2) 250 errx(1, "incompatible boot block, cannot set volume ID"); 251 boot0[OFF_SERIAL] = vol_id[0]; 252 boot0[OFF_SERIAL+1] = vol_id[1]; 253 boot0[OFF_SERIAL+2] = vol_id[2]; 254 boot0[OFF_SERIAL+3] = vol_id[3]; 255 up = 1; /* force update */ 256 } 257 /* write the MBR back to disk */ 258 if (up) 259 write_mbr(disk, 0, boot0, boot0_size); 260 261 /* display the MBR */ 262 if (v_flag) 263 display_mbr(boot0); 264 265 /* clean up */ 266 if (mbr != boot0) 267 free(boot0); 268 free(mbr); 269 free(disk); 270 271 return 0; 272} 273 274/* get or set the 'bell' character to be used in case of errors. 275 * Lookup for a certain code sequence, return -1 if not found. 276 */ 277static int 278set_bell(u_int8_t *mbr, int new_bell, int report) 279{ 280 /* lookup sequence: 0x100 means skip, 0x200 means done */ 281 static unsigned seq[] = 282 { 0xb0, 0x100, 0xe8, 0x100, 0x100, 0x30, 0xe4, 0x200 }; 283 int ofs, i, c; 284 for (ofs = 0x60; ofs < 0x180; ofs++) { /* search range */ 285 if (mbr[ofs] != seq[0]) /* search initial pattern */ 286 continue; 287 for (i=0;; i++) { 288 if (seq[i] == 0x200) { /* found */ 289 c = mbr[ofs+1]; 290 if (!report) 291 mbr[ofs+1] = c = new_bell; 292 else 293 printf(" bell=%c (0x%x)", 294 (c >= ' ' && c < 0x7f) ? c : ' ', c); 295 return c; 296 } 297 if (seq[i] != 0x100 && seq[i] != mbr[ofs+i]) 298 break; 299 } 300 } 301 warn("bell not found"); 302 return -1; 303} 304/* 305 * Read in the MBR of the disk. If it is boot0, then use the version to 306 * read in all of it if necessary. Use pointers to return a malloc'd 307 * buffer containing the MBR and then return its size. 308 */ 309static int 310read_mbr(const char *disk, u_int8_t **mbr, int check_version) 311{ 312 u_int8_t buf[MBRSIZE]; 313 int mbr_size, fd; 314 int ver; 315 ssize_t n; 316 317 if ((fd = open(disk, O_RDONLY)) == -1) 318 err(1, "open %s", disk); 319 if ((n = read(fd, buf, MBRSIZE)) == -1) 320 err(1, "read %s", disk); 321 if (n != MBRSIZE) 322 errx(1, "%s: short read", disk); 323 if (cv2(buf + OFF_MAGIC) != 0xaa55) 324 errx(1, "%s: bad magic", disk); 325 326 if (! (ver = boot0bs(buf))) { 327 if (check_version) 328 errx(1, "%s: unknown or incompatible boot code", disk); 329 } else if (boot0version(buf) == 0x101) { 330 mbr_size = 1024; 331 if ((*mbr = malloc(mbr_size)) == NULL) 332 errx(1, "%s: unable to allocate read buffer", disk); 333 if (lseek(fd, 0, SEEK_SET) == -1 || 334 (n = read(fd, *mbr, mbr_size)) == -1) 335 err(1, "%s", disk); 336 if (n != mbr_size) 337 errx(1, "%s: short read", disk); 338 close(fd); 339 return (mbr_size); 340 } 341 if ((*mbr = malloc(sizeof(buf))) == NULL) 342 errx(1, "%s: unable to allocate MBR buffer", disk); 343 memcpy(*mbr, buf, sizeof(buf)); 344 close(fd); 345 346 return sizeof(buf); 347} 348 349static int 350geom_class_available(const char *name) 351{ 352 struct gclass *class; 353 struct gmesh mesh; 354 int error; 355 356 error = geom_gettree(&mesh); 357 if (error != 0) 358 errc(1, error, "Cannot get GEOM tree"); 359 360 LIST_FOREACH(class, &mesh.lg_class, lg_class) { 361 if (strcmp(class->lg_name, name) == 0) { 362 geom_deletetree(&mesh); 363 return (1); 364 } 365 } 366 367 geom_deletetree(&mesh); 368 return (0); 369} 370 371/* 372 * Write out the mbr to the specified file. 373 */ 374static void 375write_mbr(const char *fname, int flags, u_int8_t *mbr, int mbr_size) 376{ 377 struct gctl_req *grq; 378 const char *errmsg; 379 char *pname; 380 ssize_t n; 381 int fd; 382 383 fd = open(fname, O_WRONLY | flags, 0666); 384 if (fd != -1) { 385 n = write(fd, mbr, mbr_size); 386 close(fd); 387 if (n != mbr_size) 388 errx(1, "%s: short write", fname); 389 return; 390 } 391 392 /* 393 * If we're called to write to a backup file, don't try to 394 * write through GEOM. 395 */ 396 if (flags != 0) 397 err(1, "can't open file %s to write backup", fname); 398 399 /* Try open it read only. */ 400 fd = open(fname, O_RDONLY); 401 if (fd == -1) { 402 warn("error opening %s", fname); 403 return; 404 } 405 406 pname = g_providername(fd); 407 if (pname == NULL) { 408 warn("error getting providername for %s", fname); 409 return; 410 } 411 412 /* First check that GEOM_PART is available */ 413 if (geom_class_available("PART") != 0) { 414 grq = gctl_get_handle(); 415 gctl_ro_param(grq, "class", -1, "PART"); 416 gctl_ro_param(grq, "arg0", -1, pname); 417 gctl_ro_param(grq, "verb", -1, "bootcode"); 418 gctl_ro_param(grq, "bootcode", mbr_size, mbr); 419 gctl_ro_param(grq, "flags", -1, "C"); 420 errmsg = gctl_issue(grq); 421 if (errmsg != NULL && errmsg[0] != '\0') 422 errx(1, "GEOM_PART: write bootcode to %s failed: %s", 423 fname, errmsg); 424 gctl_free(grq); 425 } else if (geom_class_available("MBR") != 0) { 426 grq = gctl_get_handle(); 427 gctl_ro_param(grq, "verb", -1, "write MBR"); 428 gctl_ro_param(grq, "class", -1, "MBR"); 429 gctl_ro_param(grq, "geom", -1, pname); 430 gctl_ro_param(grq, "data", mbr_size, mbr); 431 errmsg = gctl_issue(grq); 432 if (errmsg != NULL) 433 err(1, "GEOM_MBR: write MBR to %s failed", fname); 434 gctl_free(grq); 435 } else 436 errx(1, "can't write MBR to %s", fname); 437 free(pname); 438} 439 440/* 441 * Outputs an informative dump of the data in the MBR to stdout. 442 */ 443static void 444display_mbr(u_int8_t *mbr) 445{ 446 struct dos_partition *part; 447 int i, version; 448 449 part = (struct dos_partition *)(mbr + DOSPARTOFF); 450 printf(fmt0); 451 for (i = 0; i < NDOSPART; i++) 452 if (part[i].dp_typ) 453 printf(fmt1, 1 + i, part[i].dp_flag, 454 part[i].dp_scyl + ((part[i].dp_ssect & 0xc0) << 2), 455 part[i].dp_shd, part[i].dp_ssect & 0x3f, part[i].dp_typ, 456 part[i].dp_ecyl + ((part[i].dp_esect & 0xc0) << 2), 457 part[i].dp_ehd, part[i].dp_esect & 0x3f, part[i].dp_start, 458 part[i].dp_size); 459 printf("\n"); 460 version = boot0version(mbr); 461 printf("version=%d.%d drive=0x%x mask=0x%x ticks=%u", 462 version >> 8, version & 0xff, mbr[OFF_DRIVE], 463 mbr[OFF_FLAGS] & 0xf, cv2(mbr + OFF_TICKS)); 464 set_bell(mbr, 0, 1); 465 printf("\noptions="); 466 for (i = 0; i < nopt; i++) { 467 if (i) 468 printf(","); 469 if (!(mbr[OFF_FLAGS] & 1 << (7 - i)) ^ opttbl[i].def) 470 printf("no"); 471 printf("%s", opttbl[i].tok); 472 } 473 printf("\n"); 474 if (b0_ver == 2) 475 printf("volume serial ID %02x%02x-%02x%02x\n", 476 mbr[OFF_SERIAL], mbr[OFF_SERIAL+1], 477 mbr[OFF_SERIAL+2], mbr[OFF_SERIAL+3]); 478 printf("default_selection=F%d (", mbr[OFF_OPT] + 1); 479 if (mbr[OFF_OPT] < 4) 480 printf("Slice %d", mbr[OFF_OPT] + 1); 481 else if (mbr[OFF_OPT] == 4) 482 printf("Drive 1"); 483 else 484 printf("PXE"); 485 printf(")\n"); 486} 487 488/* 489 * Return the boot0 version with the minor revision in the low byte, and 490 * the major revision in the next higher byte. 491 */ 492static int 493boot0version(const u_int8_t *bs) 494{ 495 /* Check for old version, and return 0x100 if found. */ 496 int v = boot0bs(bs); 497 if (v != 0) 498 return v << 8; 499 500 /* We have a newer boot0, so extract the version number and return it. */ 501 return *(const int *)(bs + OFF_VERSION) & 0xffff; 502} 503 504/* descriptor of a pattern to match. 505 * Start from the first entry trying to match the chunk of bytes, 506 * if you hit an entry with len=0 terminate the search and report 507 * off as the version. Otherwise skip to the next block after len=0 508 * An entry with len=0, off=0 is the end marker. 509 */ 510struct byte_pattern { 511 unsigned off; 512 unsigned len; 513 u_int8_t *key; 514}; 515 516/* 517 * Decide if we have valid boot0 boot code by looking for 518 * characteristic byte sequences at fixed offsets. 519 */ 520static int 521boot0bs(const u_int8_t *bs) 522{ 523 /* the initial code sequence */ 524 static u_int8_t id0[] = {0xfc, 0x31, 0xc0, 0x8e, 0xc0, 0x8e, 0xd8, 525 0x8e, 0xd0, 0xbc, 0x00, 0x7c }; 526 /* the drive id */ 527 static u_int8_t id1[] = {'D', 'r', 'i', 'v', 'e', ' '}; 528 static struct byte_pattern patterns[] = { 529 {0x0, sizeof(id0), id0}, 530 {0x1b2, sizeof(id1), id1}, 531 {1, 0, NULL}, 532 {0x0, sizeof(id0), id0}, /* version with NT support */ 533 {0x1ae, sizeof(id1), id1}, 534 {2, 0, NULL}, 535 {0, 0, NULL}, 536 }; 537 struct byte_pattern *p = patterns; 538 539 for (; p->off || p->len; p++) { 540 if (p->len == 0) 541 break; 542 if (!memcmp(bs + p->off, p->key, p->len)) /* match */ 543 continue; 544 while (p->len) /* skip to next block */ 545 p++; 546 } 547 b0_ver = p->off; /* XXX ugly side effect */ 548 return p->off; 549} 550 551/* 552 * Adjust "and" and "or" masks for a -o option argument. 553 */ 554static void 555stropt(const char *arg, int *xa, int *xo) 556{ 557 const char *q; 558 char *s, *s1; 559 int inv, i, x; 560 561 if (!(s = strdup(arg))) 562 err(1, NULL); 563 for (s1 = s; (q = strtok(s1, ",")); s1 = NULL) { 564 if ((inv = !strncmp(q, "no", 2))) 565 q += 2; 566 for (i = 0; i < nopt; i++) 567 if (!strcmp(q, opttbl[i].tok)) 568 break; 569 if (i == nopt) 570 errx(1, "%s: Unknown -o option", q); 571 if (opttbl[i].def) 572 inv ^= 1; 573 x = 1 << (7 - i); 574 if (inv) 575 *xa &= ~x; 576 else 577 *xo |= x; 578 } 579 free(s); 580} 581 582/* 583 * Convert and check an option argument. 584 */ 585static int 586argtoi(const char *arg, int lo, int hi, int opt) 587{ 588 char *s; 589 long x; 590 591 errno = 0; 592 x = strtol(arg, &s, 0); 593 if (errno || !*arg || *s || x < lo || x > hi) 594 errx(1, "%s: Bad argument to -%c option", arg, opt); 595 return x; 596} 597 598/* 599 * Display usage information. 600 */ 601static void 602usage(void) 603{ 604 fprintf(stderr, "%s\n%s\n", 605 "usage: boot0cfg [-Bv] [-b boot0] [-d drive] [-f file] [-m mask]", 606 " [-o options] [-s slice] [-t ticks] disk"); 607 exit(1); 608} 609