1 /* 2 * fs/partitions/msdos.c 3 * 4 * Code extracted from drivers/block/genhd.c 5 * Copyright (C) 1991-1998 Linus Torvalds 6 * 7 * Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug 8 * in the early extended-partition checks and added DM partitions 9 * 10 * Support for DiskManager v6.0x added by Mark Lord, 11 * with information provided by OnTrack. This now works for linux fdisk 12 * and LILO, as well as loadlin and bootln. Note that disks other than 13 * /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1). 14 * 15 * More flexible handling of extended partitions - aeb, 950831 16 * 17 * Check partition table on IDE disks for common CHS translations 18 * 19 * Re-organised Feb 1998 Russell King 20 */ 21 #include <linux/msdos_fs.h> 22 23 #include "check.h" 24 #include "msdos.h" 25 #include "efi.h" 26 #include "aix.h" 27 28 /* 29 * Many architectures don't like unaligned accesses, while 30 * the nr_sects and start_sect partition table entries are 31 * at a 2 (mod 4) address. 32 */ 33 #include <asm/unaligned.h> 34 35 #define SYS_IND(p) get_unaligned(&p->sys_ind) 36 37 static inline sector_t nr_sects(struct partition *p) 38 { 39 return (sector_t)get_unaligned_le32(&p->nr_sects); 40 } 41 42 static inline sector_t start_sect(struct partition *p) 43 { 44 return (sector_t)get_unaligned_le32(&p->start_sect); 45 } 46 47 static inline int is_extended_partition(struct partition *p) 48 { 49 return (SYS_IND(p) == DOS_EXTENDED_PARTITION || 50 SYS_IND(p) == WIN98_EXTENDED_PARTITION || 51 SYS_IND(p) == LINUX_EXTENDED_PARTITION); 52 } 53 54 #define MSDOS_LABEL_MAGIC1 0x55 55 #define MSDOS_LABEL_MAGIC2 0xAA 56 57 static inline int 58 msdos_magic_present(unsigned char *p) 59 { 60 return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2); 61 } 62 63 /* Value is EBCDIC 'IBMA' */ 64 #define AIX_LABEL_MAGIC1 0xC9 65 #define AIX_LABEL_MAGIC2 0xC2 66 #define AIX_LABEL_MAGIC3 0xD4 67 #define AIX_LABEL_MAGIC4 0xC1 68 static int aix_magic_present(struct parsed_partitions *state, unsigned char *p) 69 { 70 struct partition *pt = (struct partition *) (p + 0x1be); 71 Sector sect; 72 unsigned char *d; 73 int slot, ret = 0; 74 75 if (!(p[0] == AIX_LABEL_MAGIC1 && 76 p[1] == AIX_LABEL_MAGIC2 && 77 p[2] == AIX_LABEL_MAGIC3 && 78 p[3] == AIX_LABEL_MAGIC4)) 79 return 0; 80 /* Assume the partition table is valid if Linux partitions exists */ 81 for (slot = 1; slot <= 4; slot++, pt++) { 82 if (pt->sys_ind == LINUX_SWAP_PARTITION || 83 pt->sys_ind == LINUX_RAID_PARTITION || 84 pt->sys_ind == LINUX_DATA_PARTITION || 85 pt->sys_ind == LINUX_LVM_PARTITION || 86 is_extended_partition(pt)) 87 return 0; 88 } 89 d = read_part_sector(state, 7, §); 90 if (d) { 91 if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M') 92 ret = 1; 93 put_dev_sector(sect); 94 } 95 return ret; 96 } 97 98 static void set_info(struct parsed_partitions *state, int slot, 99 u32 disksig) 100 { 101 struct partition_meta_info *info = &state->parts[slot].info; 102 103 snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig, 104 slot); 105 info->volname[0] = 0; 106 state->parts[slot].has_info = true; 107 } 108 109 /* 110 * Create devices for each logical partition in an extended partition. 111 * The logical partitions form a linked list, with each entry being 112 * a partition table with two entries. The first entry 113 * is the real data partition (with a start relative to the partition 114 * table start). The second is a pointer to the next logical partition 115 * (with a start relative to the entire extended partition). 116 * We do not create a Linux partition for the partition tables, but 117 * only for the actual data partitions. 118 */ 119 120 static void parse_extended(struct parsed_partitions *state, 121 sector_t first_sector, sector_t first_size, 122 u32 disksig) 123 { 124 struct partition *p; 125 Sector sect; 126 unsigned char *data; 127 sector_t this_sector, this_size; 128 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512; 129 int loopct = 0; /* number of links followed 130 without finding a data partition */ 131 int i; 132 133 this_sector = first_sector; 134 this_size = first_size; 135 136 while (1) { 137 if (++loopct > 100) 138 return; 139 if (state->next == state->limit) 140 return; 141 data = read_part_sector(state, this_sector, §); 142 if (!data) 143 return; 144 145 if (!msdos_magic_present(data + 510)) 146 goto done; 147 148 p = (struct partition *) (data + 0x1be); 149 150 /* 151 * Usually, the first entry is the real data partition, 152 * the 2nd entry is the next extended partition, or empty, 153 * and the 3rd and 4th entries are unused. 154 * However, DRDOS sometimes has the extended partition as 155 * the first entry (when the data partition is empty), 156 * and OS/2 seems to use all four entries. 157 */ 158 159 /* 160 * First process the data partition(s) 161 */ 162 for (i = 0; i < 4; i++, p++) { 163 sector_t offs, size, next; 164 165 if (!nr_sects(p) || is_extended_partition(p)) 166 continue; 167 168 /* Check the 3rd and 4th entries - 169 these sometimes contain random garbage */ 170 offs = start_sect(p)*sector_size; 171 size = nr_sects(p)*sector_size; 172 next = this_sector + offs; 173 if (i >= 2) { 174 if (offs + size > this_size) 175 continue; 176 if (next < first_sector) 177 continue; 178 if (next + size > first_sector + first_size) 179 continue; 180 } 181 182 put_partition(state, state->next, next, size); 183 set_info(state, state->next, disksig); 184 if (SYS_IND(p) == LINUX_RAID_PARTITION) 185 state->parts[state->next].flags = ADDPART_FLAG_RAID; 186 loopct = 0; 187 if (++state->next == state->limit) 188 goto done; 189 } 190 /* 191 * Next, process the (first) extended partition, if present. 192 * (So far, there seems to be no reason to make 193 * parse_extended() recursive and allow a tree 194 * of extended partitions.) 195 * It should be a link to the next logical partition. 196 */ 197 p -= 4; 198 for (i = 0; i < 4; i++, p++) 199 if (nr_sects(p) && is_extended_partition(p)) 200 break; 201 if (i == 4) 202 goto done; /* nothing left to do */ 203 204 this_sector = first_sector + start_sect(p) * sector_size; 205 this_size = nr_sects(p) * sector_size; 206 put_dev_sector(sect); 207 } 208 done: 209 put_dev_sector(sect); 210 } 211 212 /* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also 213 indicates linux swap. Be careful before believing this is Solaris. */ 214 215 static void parse_solaris_x86(struct parsed_partitions *state, 216 sector_t offset, sector_t size, int origin) 217 { 218 #ifdef CONFIG_SOLARIS_X86_PARTITION 219 Sector sect; 220 struct solaris_x86_vtoc *v; 221 int i; 222 short max_nparts; 223 224 v = read_part_sector(state, offset + 1, §); 225 if (!v) 226 return; 227 if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) { 228 put_dev_sector(sect); 229 return; 230 } 231 { 232 char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1]; 233 234 snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin); 235 strlcat(state->pp_buf, tmp, PAGE_SIZE); 236 } 237 if (le32_to_cpu(v->v_version) != 1) { 238 char tmp[64]; 239 240 snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n", 241 le32_to_cpu(v->v_version)); 242 strlcat(state->pp_buf, tmp, PAGE_SIZE); 243 put_dev_sector(sect); 244 return; 245 } 246 /* Ensure we can handle previous case of VTOC with 8 entries gracefully */ 247 max_nparts = le16_to_cpu(v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8; 248 for (i = 0; i < max_nparts && state->next < state->limit; i++) { 249 struct solaris_x86_slice *s = &v->v_slice[i]; 250 char tmp[3 + 10 + 1 + 1]; 251 252 if (s->s_size == 0) 253 continue; 254 snprintf(tmp, sizeof(tmp), " [s%d]", i); 255 strlcat(state->pp_buf, tmp, PAGE_SIZE); 256 /* solaris partitions are relative to current MS-DOS 257 * one; must add the offset of the current partition */ 258 put_partition(state, state->next++, 259 le32_to_cpu(s->s_start)+offset, 260 le32_to_cpu(s->s_size)); 261 } 262 put_dev_sector(sect); 263 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 264 #endif 265 } 266 267 #if defined(CONFIG_BSD_DISKLABEL) 268 /* 269 * Create devices for BSD partitions listed in a disklabel, under a 270 * dos-like partition. See parse_extended() for more information. 271 */ 272 static void parse_bsd(struct parsed_partitions *state, 273 sector_t offset, sector_t size, int origin, char *flavour, 274 int max_partitions) 275 { 276 Sector sect; 277 struct bsd_disklabel *l; 278 struct bsd_partition *p; 279 char tmp[64]; 280 281 l = read_part_sector(state, offset + 1, §); 282 if (!l) 283 return; 284 if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) { 285 put_dev_sector(sect); 286 return; 287 } 288 289 snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour); 290 strlcat(state->pp_buf, tmp, PAGE_SIZE); 291 292 if (le16_to_cpu(l->d_npartitions) < max_partitions) 293 max_partitions = le16_to_cpu(l->d_npartitions); 294 for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) { 295 sector_t bsd_start, bsd_size; 296 297 if (state->next == state->limit) 298 break; 299 if (p->p_fstype == BSD_FS_UNUSED) 300 continue; 301 bsd_start = le32_to_cpu(p->p_offset); 302 bsd_size = le32_to_cpu(p->p_size); 303 if (offset == bsd_start && size == bsd_size) 304 /* full parent partition, we have it already */ 305 continue; 306 if (offset > bsd_start || offset+size < bsd_start+bsd_size) { 307 strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE); 308 continue; 309 } 310 put_partition(state, state->next++, bsd_start, bsd_size); 311 } 312 put_dev_sector(sect); 313 if (le16_to_cpu(l->d_npartitions) > max_partitions) { 314 snprintf(tmp, sizeof(tmp), " (ignored %d more)", 315 le16_to_cpu(l->d_npartitions) - max_partitions); 316 strlcat(state->pp_buf, tmp, PAGE_SIZE); 317 } 318 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 319 } 320 #endif 321 322 static void parse_freebsd(struct parsed_partitions *state, 323 sector_t offset, sector_t size, int origin) 324 { 325 #ifdef CONFIG_BSD_DISKLABEL 326 parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS); 327 #endif 328 } 329 330 static void parse_netbsd(struct parsed_partitions *state, 331 sector_t offset, sector_t size, int origin) 332 { 333 #ifdef CONFIG_BSD_DISKLABEL 334 parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS); 335 #endif 336 } 337 338 static void parse_openbsd(struct parsed_partitions *state, 339 sector_t offset, sector_t size, int origin) 340 { 341 #ifdef CONFIG_BSD_DISKLABEL 342 parse_bsd(state, offset, size, origin, "openbsd", 343 OPENBSD_MAXPARTITIONS); 344 #endif 345 } 346 347 /* 348 * Create devices for Unixware partitions listed in a disklabel, under a 349 * dos-like partition. See parse_extended() for more information. 350 */ 351 static void parse_unixware(struct parsed_partitions *state, 352 sector_t offset, sector_t size, int origin) 353 { 354 #ifdef CONFIG_UNIXWARE_DISKLABEL 355 Sector sect; 356 struct unixware_disklabel *l; 357 struct unixware_slice *p; 358 359 l = read_part_sector(state, offset + 29, §); 360 if (!l) 361 return; 362 if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC || 363 le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) { 364 put_dev_sector(sect); 365 return; 366 } 367 { 368 char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1]; 369 370 snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin); 371 strlcat(state->pp_buf, tmp, PAGE_SIZE); 372 } 373 p = &l->vtoc.v_slice[1]; 374 /* I omit the 0th slice as it is the same as whole disk. */ 375 while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) { 376 if (state->next == state->limit) 377 break; 378 379 if (p->s_label != UNIXWARE_FS_UNUSED) 380 put_partition(state, state->next++, 381 le32_to_cpu(p->start_sect), 382 le32_to_cpu(p->nr_sects)); 383 p++; 384 } 385 put_dev_sector(sect); 386 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 387 #endif 388 } 389 390 /* 391 * Minix 2.0.0/2.0.2 subpartition support. 392 * Anand Krishnamurthy <anandk@wiproge.med.ge.com> 393 * Rajeev V. Pillai <rajeevvp@yahoo.com> 394 */ 395 static void parse_minix(struct parsed_partitions *state, 396 sector_t offset, sector_t size, int origin) 397 { 398 #ifdef CONFIG_MINIX_SUBPARTITION 399 Sector sect; 400 unsigned char *data; 401 struct partition *p; 402 int i; 403 404 data = read_part_sector(state, offset, §); 405 if (!data) 406 return; 407 408 p = (struct partition *)(data + 0x1be); 409 410 /* The first sector of a Minix partition can have either 411 * a secondary MBR describing its subpartitions, or 412 * the normal boot sector. */ 413 if (msdos_magic_present(data + 510) && 414 SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */ 415 char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1]; 416 417 snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin); 418 strlcat(state->pp_buf, tmp, PAGE_SIZE); 419 for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) { 420 if (state->next == state->limit) 421 break; 422 /* add each partition in use */ 423 if (SYS_IND(p) == MINIX_PARTITION) 424 put_partition(state, state->next++, 425 start_sect(p), nr_sects(p)); 426 } 427 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 428 } 429 put_dev_sector(sect); 430 #endif /* CONFIG_MINIX_SUBPARTITION */ 431 } 432 433 static struct { 434 unsigned char id; 435 void (*parse)(struct parsed_partitions *, sector_t, sector_t, int); 436 } subtypes[] = { 437 {FREEBSD_PARTITION, parse_freebsd}, 438 {NETBSD_PARTITION, parse_netbsd}, 439 {OPENBSD_PARTITION, parse_openbsd}, 440 {MINIX_PARTITION, parse_minix}, 441 {UNIXWARE_PARTITION, parse_unixware}, 442 {SOLARIS_X86_PARTITION, parse_solaris_x86}, 443 {NEW_SOLARIS_X86_PARTITION, parse_solaris_x86}, 444 {0, NULL}, 445 }; 446 447 int msdos_partition(struct parsed_partitions *state) 448 { 449 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512; 450 Sector sect; 451 unsigned char *data; 452 struct partition *p; 453 struct fat_boot_sector *fb; 454 int slot; 455 u32 disksig; 456 457 data = read_part_sector(state, 0, §); 458 if (!data) 459 return -1; 460 461 /* 462 * Note order! (some AIX disks, e.g. unbootable kind, 463 * have no MSDOS 55aa) 464 */ 465 if (aix_magic_present(state, data)) { 466 put_dev_sector(sect); 467 #ifdef CONFIG_AIX_PARTITION 468 return aix_partition(state); 469 #else 470 strlcat(state->pp_buf, " [AIX]", PAGE_SIZE); 471 return 0; 472 #endif 473 } 474 475 if (!msdos_magic_present(data + 510)) { 476 put_dev_sector(sect); 477 return 0; 478 } 479 480 /* 481 * Now that the 55aa signature is present, this is probably 482 * either the boot sector of a FAT filesystem or a DOS-type 483 * partition table. Reject this in case the boot indicator 484 * is not 0 or 0x80. 485 */ 486 p = (struct partition *) (data + 0x1be); 487 for (slot = 1; slot <= 4; slot++, p++) { 488 if (p->boot_ind != 0 && p->boot_ind != 0x80) { 489 /* 490 * Even without a valid boot inidicator value 491 * its still possible this is valid FAT filesystem 492 * without a partition table. 493 */ 494 fb = (struct fat_boot_sector *) data; 495 if (slot == 1 && fb->reserved && fb->fats 496 && fat_valid_media(fb->media)) { 497 strlcat(state->pp_buf, "\n", PAGE_SIZE); 498 put_dev_sector(sect); 499 return 1; 500 } else { 501 put_dev_sector(sect); 502 return 0; 503 } 504 } 505 } 506 507 #ifdef CONFIG_EFI_PARTITION 508 p = (struct partition *) (data + 0x1be); 509 for (slot = 1 ; slot <= 4 ; slot++, p++) { 510 /* If this is an EFI GPT disk, msdos should ignore it. */ 511 if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) { 512 put_dev_sector(sect); 513 return 0; 514 } 515 } 516 #endif 517 p = (struct partition *) (data + 0x1be); 518 519 disksig = le32_to_cpup((__le32 *)(data + 0x1b8)); 520 521 /* 522 * Look for partitions in two passes: 523 * First find the primary and DOS-type extended partitions. 524 * On the second pass look inside *BSD, Unixware and Solaris partitions. 525 */ 526 527 state->next = 5; 528 for (slot = 1 ; slot <= 4 ; slot++, p++) { 529 sector_t start = start_sect(p)*sector_size; 530 sector_t size = nr_sects(p)*sector_size; 531 532 if (!size) 533 continue; 534 if (is_extended_partition(p)) { 535 /* 536 * prevent someone doing mkfs or mkswap on an 537 * extended partition, but leave room for LILO 538 * FIXME: this uses one logical sector for > 512b 539 * sector, although it may not be enough/proper. 540 */ 541 sector_t n = 2; 542 543 n = min(size, max(sector_size, n)); 544 put_partition(state, slot, start, n); 545 546 strlcat(state->pp_buf, " <", PAGE_SIZE); 547 parse_extended(state, start, size, disksig); 548 strlcat(state->pp_buf, " >", PAGE_SIZE); 549 continue; 550 } 551 put_partition(state, slot, start, size); 552 set_info(state, slot, disksig); 553 if (SYS_IND(p) == LINUX_RAID_PARTITION) 554 state->parts[slot].flags = ADDPART_FLAG_RAID; 555 if (SYS_IND(p) == DM6_PARTITION) 556 strlcat(state->pp_buf, "[DM]", PAGE_SIZE); 557 if (SYS_IND(p) == EZD_PARTITION) 558 strlcat(state->pp_buf, "[EZD]", PAGE_SIZE); 559 } 560 561 strlcat(state->pp_buf, "\n", PAGE_SIZE); 562 563 /* second pass - output for each on a separate line */ 564 p = (struct partition *) (0x1be + data); 565 for (slot = 1 ; slot <= 4 ; slot++, p++) { 566 unsigned char id = SYS_IND(p); 567 int n; 568 569 if (!nr_sects(p)) 570 continue; 571 572 for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++) 573 ; 574 575 if (!subtypes[n].parse) 576 continue; 577 subtypes[n].parse(state, start_sect(p) * sector_size, 578 nr_sects(p) * sector_size, slot); 579 } 580 put_dev_sector(sect); 581 return 1; 582 } 583