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 if (!nr_sects(p) || is_extended_partition(p)) 165 continue; 166 167 /* Check the 3rd and 4th entries - 168 these sometimes contain random garbage */ 169 offs = start_sect(p)*sector_size; 170 size = nr_sects(p)*sector_size; 171 next = this_sector + offs; 172 if (i >= 2) { 173 if (offs + size > this_size) 174 continue; 175 if (next < first_sector) 176 continue; 177 if (next + size > first_sector + first_size) 178 continue; 179 } 180 181 put_partition(state, state->next, next, size); 182 set_info(state, state->next, disksig); 183 if (SYS_IND(p) == LINUX_RAID_PARTITION) 184 state->parts[state->next].flags = ADDPART_FLAG_RAID; 185 loopct = 0; 186 if (++state->next == state->limit) 187 goto done; 188 } 189 /* 190 * Next, process the (first) extended partition, if present. 191 * (So far, there seems to be no reason to make 192 * parse_extended() recursive and allow a tree 193 * of extended partitions.) 194 * It should be a link to the next logical partition. 195 */ 196 p -= 4; 197 for (i=0; i<4; i++, p++) 198 if (nr_sects(p) && is_extended_partition(p)) 199 break; 200 if (i == 4) 201 goto done; /* nothing left to do */ 202 203 this_sector = first_sector + start_sect(p) * sector_size; 204 this_size = nr_sects(p) * sector_size; 205 put_dev_sector(sect); 206 } 207 done: 208 put_dev_sector(sect); 209 } 210 211 /* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also 212 indicates linux swap. Be careful before believing this is Solaris. */ 213 214 static void parse_solaris_x86(struct parsed_partitions *state, 215 sector_t offset, sector_t size, int origin) 216 { 217 #ifdef CONFIG_SOLARIS_X86_PARTITION 218 Sector sect; 219 struct solaris_x86_vtoc *v; 220 int i; 221 short max_nparts; 222 223 v = read_part_sector(state, offset + 1, §); 224 if (!v) 225 return; 226 if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) { 227 put_dev_sector(sect); 228 return; 229 } 230 { 231 char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1]; 232 233 snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin); 234 strlcat(state->pp_buf, tmp, PAGE_SIZE); 235 } 236 if (le32_to_cpu(v->v_version) != 1) { 237 char tmp[64]; 238 239 snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n", 240 le32_to_cpu(v->v_version)); 241 strlcat(state->pp_buf, tmp, PAGE_SIZE); 242 put_dev_sector(sect); 243 return; 244 } 245 /* Ensure we can handle previous case of VTOC with 8 entries gracefully */ 246 max_nparts = le16_to_cpu (v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8; 247 for (i=0; i<max_nparts && state->next<state->limit; i++) { 248 struct solaris_x86_slice *s = &v->v_slice[i]; 249 char tmp[3 + 10 + 1 + 1]; 250 251 if (s->s_size == 0) 252 continue; 253 snprintf(tmp, sizeof(tmp), " [s%d]", i); 254 strlcat(state->pp_buf, tmp, PAGE_SIZE); 255 /* solaris partitions are relative to current MS-DOS 256 * one; must add the offset of the current partition */ 257 put_partition(state, state->next++, 258 le32_to_cpu(s->s_start)+offset, 259 le32_to_cpu(s->s_size)); 260 } 261 put_dev_sector(sect); 262 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 263 #endif 264 } 265 266 #if defined(CONFIG_BSD_DISKLABEL) 267 /* 268 * Create devices for BSD partitions listed in a disklabel, under a 269 * dos-like partition. See parse_extended() for more information. 270 */ 271 static void parse_bsd(struct parsed_partitions *state, 272 sector_t offset, sector_t size, int origin, char *flavour, 273 int max_partitions) 274 { 275 Sector sect; 276 struct bsd_disklabel *l; 277 struct bsd_partition *p; 278 char tmp[64]; 279 280 l = read_part_sector(state, offset + 1, §); 281 if (!l) 282 return; 283 if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) { 284 put_dev_sector(sect); 285 return; 286 } 287 288 snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour); 289 strlcat(state->pp_buf, tmp, PAGE_SIZE); 290 291 if (le16_to_cpu(l->d_npartitions) < max_partitions) 292 max_partitions = le16_to_cpu(l->d_npartitions); 293 for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) { 294 sector_t bsd_start, bsd_size; 295 296 if (state->next == state->limit) 297 break; 298 if (p->p_fstype == BSD_FS_UNUSED) 299 continue; 300 bsd_start = le32_to_cpu(p->p_offset); 301 bsd_size = le32_to_cpu(p->p_size); 302 if (offset == bsd_start && size == bsd_size) 303 /* full parent partition, we have it already */ 304 continue; 305 if (offset > bsd_start || offset+size < bsd_start+bsd_size) { 306 strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE); 307 continue; 308 } 309 put_partition(state, state->next++, bsd_start, bsd_size); 310 } 311 put_dev_sector(sect); 312 if (le16_to_cpu(l->d_npartitions) > max_partitions) { 313 snprintf(tmp, sizeof(tmp), " (ignored %d more)", 314 le16_to_cpu(l->d_npartitions) - max_partitions); 315 strlcat(state->pp_buf, tmp, PAGE_SIZE); 316 } 317 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 318 } 319 #endif 320 321 static void parse_freebsd(struct parsed_partitions *state, 322 sector_t offset, sector_t size, int origin) 323 { 324 #ifdef CONFIG_BSD_DISKLABEL 325 parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS); 326 #endif 327 } 328 329 static void parse_netbsd(struct parsed_partitions *state, 330 sector_t offset, sector_t size, int origin) 331 { 332 #ifdef CONFIG_BSD_DISKLABEL 333 parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS); 334 #endif 335 } 336 337 static void parse_openbsd(struct parsed_partitions *state, 338 sector_t offset, sector_t size, int origin) 339 { 340 #ifdef CONFIG_BSD_DISKLABEL 341 parse_bsd(state, offset, size, origin, "openbsd", 342 OPENBSD_MAXPARTITIONS); 343 #endif 344 } 345 346 /* 347 * Create devices for Unixware partitions listed in a disklabel, under a 348 * dos-like partition. See parse_extended() for more information. 349 */ 350 static void parse_unixware(struct parsed_partitions *state, 351 sector_t offset, sector_t size, int origin) 352 { 353 #ifdef CONFIG_UNIXWARE_DISKLABEL 354 Sector sect; 355 struct unixware_disklabel *l; 356 struct unixware_slice *p; 357 358 l = read_part_sector(state, offset + 29, §); 359 if (!l) 360 return; 361 if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC || 362 le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) { 363 put_dev_sector(sect); 364 return; 365 } 366 { 367 char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1]; 368 369 snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin); 370 strlcat(state->pp_buf, tmp, PAGE_SIZE); 371 } 372 p = &l->vtoc.v_slice[1]; 373 /* I omit the 0th slice as it is the same as whole disk. */ 374 while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) { 375 if (state->next == state->limit) 376 break; 377 378 if (p->s_label != UNIXWARE_FS_UNUSED) 379 put_partition(state, state->next++, 380 le32_to_cpu(p->start_sect), 381 le32_to_cpu(p->nr_sects)); 382 p++; 383 } 384 put_dev_sector(sect); 385 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 386 #endif 387 } 388 389 /* 390 * Minix 2.0.0/2.0.2 subpartition support. 391 * Anand Krishnamurthy <anandk@wiproge.med.ge.com> 392 * Rajeev V. Pillai <rajeevvp@yahoo.com> 393 */ 394 static void parse_minix(struct parsed_partitions *state, 395 sector_t offset, sector_t size, int origin) 396 { 397 #ifdef CONFIG_MINIX_SUBPARTITION 398 Sector sect; 399 unsigned char *data; 400 struct partition *p; 401 int i; 402 403 data = read_part_sector(state, offset, §); 404 if (!data) 405 return; 406 407 p = (struct partition *)(data + 0x1be); 408 409 /* The first sector of a Minix partition can have either 410 * a secondary MBR describing its subpartitions, or 411 * the normal boot sector. */ 412 if (msdos_magic_present (data + 510) && 413 SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */ 414 char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1]; 415 416 snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin); 417 strlcat(state->pp_buf, tmp, PAGE_SIZE); 418 for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) { 419 if (state->next == state->limit) 420 break; 421 /* add each partition in use */ 422 if (SYS_IND(p) == MINIX_PARTITION) 423 put_partition(state, state->next++, 424 start_sect(p), nr_sects(p)); 425 } 426 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 427 } 428 put_dev_sector(sect); 429 #endif /* CONFIG_MINIX_SUBPARTITION */ 430 } 431 432 static struct { 433 unsigned char id; 434 void (*parse)(struct parsed_partitions *, sector_t, sector_t, int); 435 } subtypes[] = { 436 {FREEBSD_PARTITION, parse_freebsd}, 437 {NETBSD_PARTITION, parse_netbsd}, 438 {OPENBSD_PARTITION, parse_openbsd}, 439 {MINIX_PARTITION, parse_minix}, 440 {UNIXWARE_PARTITION, parse_unixware}, 441 {SOLARIS_X86_PARTITION, parse_solaris_x86}, 442 {NEW_SOLARIS_X86_PARTITION, parse_solaris_x86}, 443 {0, NULL}, 444 }; 445 446 int msdos_partition(struct parsed_partitions *state) 447 { 448 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512; 449 Sector sect; 450 unsigned char *data; 451 struct partition *p; 452 struct fat_boot_sector *fb; 453 int slot; 454 u32 disksig; 455 456 data = read_part_sector(state, 0, §); 457 if (!data) 458 return -1; 459 460 /* 461 * Note order! (some AIX disks, e.g. unbootable kind, 462 * have no MSDOS 55aa) 463 */ 464 if (aix_magic_present(state, data)) { 465 put_dev_sector(sect); 466 #ifdef CONFIG_AIX_PARTITION 467 return aix_partition(state); 468 #else 469 strlcat(state->pp_buf, " [AIX]", PAGE_SIZE); 470 return 0; 471 #endif 472 } 473 474 if (!msdos_magic_present(data + 510)) { 475 put_dev_sector(sect); 476 return 0; 477 } 478 479 /* 480 * Now that the 55aa signature is present, this is probably 481 * either the boot sector of a FAT filesystem or a DOS-type 482 * partition table. Reject this in case the boot indicator 483 * is not 0 or 0x80. 484 */ 485 p = (struct partition *) (data + 0x1be); 486 for (slot = 1; slot <= 4; slot++, p++) { 487 if (p->boot_ind != 0 && p->boot_ind != 0x80) { 488 /* 489 * Even without a valid boot inidicator value 490 * its still possible this is valid FAT filesystem 491 * without a partition table. 492 */ 493 fb = (struct fat_boot_sector *) data; 494 if (slot == 1 && fb->reserved && fb->fats 495 && fat_valid_media(fb->media)) { 496 strlcat(state->pp_buf, "\n", PAGE_SIZE); 497 put_dev_sector(sect); 498 return 1; 499 } else { 500 put_dev_sector(sect); 501 return 0; 502 } 503 } 504 } 505 506 #ifdef CONFIG_EFI_PARTITION 507 p = (struct partition *) (data + 0x1be); 508 for (slot = 1 ; slot <= 4 ; slot++, p++) { 509 /* If this is an EFI GPT disk, msdos should ignore it. */ 510 if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) { 511 put_dev_sector(sect); 512 return 0; 513 } 514 } 515 #endif 516 p = (struct partition *) (data + 0x1be); 517 518 disksig = le32_to_cpup((__le32 *)(data + 0x1b8)); 519 520 /* 521 * Look for partitions in two passes: 522 * First find the primary and DOS-type extended partitions. 523 * On the second pass look inside *BSD, Unixware and Solaris partitions. 524 */ 525 526 state->next = 5; 527 for (slot = 1 ; slot <= 4 ; slot++, p++) { 528 sector_t start = start_sect(p)*sector_size; 529 sector_t size = nr_sects(p)*sector_size; 530 if (!size) 531 continue; 532 if (is_extended_partition(p)) { 533 /* 534 * prevent someone doing mkfs or mkswap on an 535 * extended partition, but leave room for LILO 536 * FIXME: this uses one logical sector for > 512b 537 * sector, although it may not be enough/proper. 538 */ 539 sector_t n = 2; 540 n = min(size, max(sector_size, n)); 541 put_partition(state, slot, start, n); 542 543 strlcat(state->pp_buf, " <", PAGE_SIZE); 544 parse_extended(state, start, size, disksig); 545 strlcat(state->pp_buf, " >", PAGE_SIZE); 546 continue; 547 } 548 put_partition(state, slot, start, size); 549 set_info(state, slot, disksig); 550 if (SYS_IND(p) == LINUX_RAID_PARTITION) 551 state->parts[slot].flags = ADDPART_FLAG_RAID; 552 if (SYS_IND(p) == DM6_PARTITION) 553 strlcat(state->pp_buf, "[DM]", PAGE_SIZE); 554 if (SYS_IND(p) == EZD_PARTITION) 555 strlcat(state->pp_buf, "[EZD]", PAGE_SIZE); 556 } 557 558 strlcat(state->pp_buf, "\n", PAGE_SIZE); 559 560 /* second pass - output for each on a separate line */ 561 p = (struct partition *) (0x1be + data); 562 for (slot = 1 ; slot <= 4 ; slot++, p++) { 563 unsigned char id = SYS_IND(p); 564 int n; 565 566 if (!nr_sects(p)) 567 continue; 568 569 for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++) 570 ; 571 572 if (!subtypes[n].parse) 573 continue; 574 subtypes[n].parse(state, start_sect(p) * sector_size, 575 nr_sects(p) * sector_size, slot); 576 } 577 put_dev_sector(sect); 578 return 1; 579 } 580