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