1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * fs/partitions/msdos.c 4 * 5 * Code extracted from drivers/block/genhd.c 6 * Copyright (C) 1991-1998 Linus Torvalds 7 * 8 * Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug 9 * in the early extended-partition checks and added DM partitions 10 * 11 * Support for DiskManager v6.0x added by Mark Lord, 12 * with information provided by OnTrack. This now works for linux fdisk 13 * and LILO, as well as loadlin and bootln. Note that disks other than 14 * /dev/hda *must* have a "DOS" type 0x51 partition in the first slot (hda1). 15 * 16 * More flexible handling of extended partitions - aeb, 950831 17 * 18 * Check partition table on IDE disks for common CHS translations 19 * 20 * Re-organised Feb 1998 Russell King 21 * 22 * BSD disklabel support by Yossi Gottlieb <yogo@math.tau.ac.il> 23 * updated by Marc Espie <Marc.Espie@openbsd.org> 24 * 25 * Unixware slices support by Andrzej Krzysztofowicz <ankry@mif.pg.gda.pl> 26 * and Krzysztof G. Baranowski <kgb@knm.org.pl> 27 */ 28 #include <linux/msdos_fs.h> 29 #include <linux/msdos_partition.h> 30 31 #include "check.h" 32 #include "efi.h" 33 34 /* 35 * Many architectures don't like unaligned accesses, while 36 * the nr_sects and start_sect partition table entries are 37 * at a 2 (mod 4) address. 38 */ 39 #include <asm/unaligned.h> 40 41 #define SYS_IND(p) get_unaligned(&p->sys_ind) 42 43 static inline sector_t nr_sects(struct msdos_partition *p) 44 { 45 return (sector_t)get_unaligned_le32(&p->nr_sects); 46 } 47 48 static inline sector_t start_sect(struct msdos_partition *p) 49 { 50 return (sector_t)get_unaligned_le32(&p->start_sect); 51 } 52 53 static inline int is_extended_partition(struct msdos_partition *p) 54 { 55 return (SYS_IND(p) == DOS_EXTENDED_PARTITION || 56 SYS_IND(p) == WIN98_EXTENDED_PARTITION || 57 SYS_IND(p) == LINUX_EXTENDED_PARTITION); 58 } 59 60 #define MSDOS_LABEL_MAGIC1 0x55 61 #define MSDOS_LABEL_MAGIC2 0xAA 62 63 static inline int 64 msdos_magic_present(unsigned char *p) 65 { 66 return (p[0] == MSDOS_LABEL_MAGIC1 && p[1] == MSDOS_LABEL_MAGIC2); 67 } 68 69 /* Value is EBCDIC 'IBMA' */ 70 #define AIX_LABEL_MAGIC1 0xC9 71 #define AIX_LABEL_MAGIC2 0xC2 72 #define AIX_LABEL_MAGIC3 0xD4 73 #define AIX_LABEL_MAGIC4 0xC1 74 static int aix_magic_present(struct parsed_partitions *state, unsigned char *p) 75 { 76 struct msdos_partition *pt = (struct msdos_partition *) (p + 0x1be); 77 Sector sect; 78 unsigned char *d; 79 int slot, ret = 0; 80 81 if (!(p[0] == AIX_LABEL_MAGIC1 && 82 p[1] == AIX_LABEL_MAGIC2 && 83 p[2] == AIX_LABEL_MAGIC3 && 84 p[3] == AIX_LABEL_MAGIC4)) 85 return 0; 86 87 /* 88 * Assume the partition table is valid if Linux partitions exists. 89 * Note that old Solaris/x86 partitions use the same indicator as 90 * Linux swap partitions, so we consider that a Linux partition as 91 * well. 92 */ 93 for (slot = 1; slot <= 4; slot++, pt++) { 94 if (pt->sys_ind == SOLARIS_X86_PARTITION || 95 pt->sys_ind == LINUX_RAID_PARTITION || 96 pt->sys_ind == LINUX_DATA_PARTITION || 97 pt->sys_ind == LINUX_LVM_PARTITION || 98 is_extended_partition(pt)) 99 return 0; 100 } 101 d = read_part_sector(state, 7, §); 102 if (d) { 103 if (d[0] == '_' && d[1] == 'L' && d[2] == 'V' && d[3] == 'M') 104 ret = 1; 105 put_dev_sector(sect); 106 } 107 return ret; 108 } 109 110 static void set_info(struct parsed_partitions *state, int slot, 111 u32 disksig) 112 { 113 struct partition_meta_info *info = &state->parts[slot].info; 114 115 snprintf(info->uuid, sizeof(info->uuid), "%08x-%02x", disksig, 116 slot); 117 info->volname[0] = 0; 118 state->parts[slot].has_info = true; 119 } 120 121 /* 122 * Create devices for each logical partition in an extended partition. 123 * The logical partitions form a linked list, with each entry being 124 * a partition table with two entries. The first entry 125 * is the real data partition (with a start relative to the partition 126 * table start). The second is a pointer to the next logical partition 127 * (with a start relative to the entire extended partition). 128 * We do not create a Linux partition for the partition tables, but 129 * only for the actual data partitions. 130 */ 131 132 static void parse_extended(struct parsed_partitions *state, 133 sector_t first_sector, sector_t first_size, 134 u32 disksig) 135 { 136 struct msdos_partition *p; 137 Sector sect; 138 unsigned char *data; 139 sector_t this_sector, this_size; 140 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512; 141 int loopct = 0; /* number of links followed 142 without finding a data partition */ 143 int i; 144 145 this_sector = first_sector; 146 this_size = first_size; 147 148 while (1) { 149 if (++loopct > 100) 150 return; 151 if (state->next == state->limit) 152 return; 153 data = read_part_sector(state, this_sector, §); 154 if (!data) 155 return; 156 157 if (!msdos_magic_present(data + 510)) 158 goto done; 159 160 p = (struct msdos_partition *) (data + 0x1be); 161 162 /* 163 * Usually, the first entry is the real data partition, 164 * the 2nd entry is the next extended partition, or empty, 165 * and the 3rd and 4th entries are unused. 166 * However, DRDOS sometimes has the extended partition as 167 * the first entry (when the data partition is empty), 168 * and OS/2 seems to use all four entries. 169 */ 170 171 /* 172 * First process the data partition(s) 173 */ 174 for (i = 0; i < 4; i++, p++) { 175 sector_t offs, size, next; 176 177 if (!nr_sects(p) || is_extended_partition(p)) 178 continue; 179 180 /* Check the 3rd and 4th entries - 181 these sometimes contain random garbage */ 182 offs = start_sect(p)*sector_size; 183 size = nr_sects(p)*sector_size; 184 next = this_sector + offs; 185 if (i >= 2) { 186 if (offs + size > this_size) 187 continue; 188 if (next < first_sector) 189 continue; 190 if (next + size > first_sector + first_size) 191 continue; 192 } 193 194 put_partition(state, state->next, next, size); 195 set_info(state, state->next, disksig); 196 if (SYS_IND(p) == LINUX_RAID_PARTITION) 197 state->parts[state->next].flags = ADDPART_FLAG_RAID; 198 loopct = 0; 199 if (++state->next == state->limit) 200 goto done; 201 } 202 /* 203 * Next, process the (first) extended partition, if present. 204 * (So far, there seems to be no reason to make 205 * parse_extended() recursive and allow a tree 206 * of extended partitions.) 207 * It should be a link to the next logical partition. 208 */ 209 p -= 4; 210 for (i = 0; i < 4; i++, p++) 211 if (nr_sects(p) && is_extended_partition(p)) 212 break; 213 if (i == 4) 214 goto done; /* nothing left to do */ 215 216 this_sector = first_sector + start_sect(p) * sector_size; 217 this_size = nr_sects(p) * sector_size; 218 put_dev_sector(sect); 219 } 220 done: 221 put_dev_sector(sect); 222 } 223 224 #define SOLARIS_X86_NUMSLICE 16 225 #define SOLARIS_X86_VTOC_SANE (0x600DDEEEUL) 226 227 struct solaris_x86_slice { 228 __le16 s_tag; /* ID tag of partition */ 229 __le16 s_flag; /* permission flags */ 230 __le32 s_start; /* start sector no of partition */ 231 __le32 s_size; /* # of blocks in partition */ 232 }; 233 234 struct solaris_x86_vtoc { 235 unsigned int v_bootinfo[3]; /* info needed by mboot */ 236 __le32 v_sanity; /* to verify vtoc sanity */ 237 __le32 v_version; /* layout version */ 238 char v_volume[8]; /* volume name */ 239 __le16 v_sectorsz; /* sector size in bytes */ 240 __le16 v_nparts; /* number of partitions */ 241 unsigned int v_reserved[10]; /* free space */ 242 struct solaris_x86_slice 243 v_slice[SOLARIS_X86_NUMSLICE]; /* slice headers */ 244 unsigned int timestamp[SOLARIS_X86_NUMSLICE]; /* timestamp */ 245 char v_asciilabel[128]; /* for compatibility */ 246 }; 247 248 /* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also 249 indicates linux swap. Be careful before believing this is Solaris. */ 250 251 static void parse_solaris_x86(struct parsed_partitions *state, 252 sector_t offset, sector_t size, int origin) 253 { 254 #ifdef CONFIG_SOLARIS_X86_PARTITION 255 Sector sect; 256 struct solaris_x86_vtoc *v; 257 int i; 258 short max_nparts; 259 260 v = read_part_sector(state, offset + 1, §); 261 if (!v) 262 return; 263 if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) { 264 put_dev_sector(sect); 265 return; 266 } 267 { 268 char tmp[1 + BDEVNAME_SIZE + 10 + 11 + 1]; 269 270 snprintf(tmp, sizeof(tmp), " %s%d: <solaris:", state->name, origin); 271 strlcat(state->pp_buf, tmp, PAGE_SIZE); 272 } 273 if (le32_to_cpu(v->v_version) != 1) { 274 char tmp[64]; 275 276 snprintf(tmp, sizeof(tmp), " cannot handle version %d vtoc>\n", 277 le32_to_cpu(v->v_version)); 278 strlcat(state->pp_buf, tmp, PAGE_SIZE); 279 put_dev_sector(sect); 280 return; 281 } 282 /* Ensure we can handle previous case of VTOC with 8 entries gracefully */ 283 max_nparts = le16_to_cpu(v->v_nparts) > 8 ? SOLARIS_X86_NUMSLICE : 8; 284 for (i = 0; i < max_nparts && state->next < state->limit; i++) { 285 struct solaris_x86_slice *s = &v->v_slice[i]; 286 char tmp[3 + 10 + 1 + 1]; 287 288 if (s->s_size == 0) 289 continue; 290 snprintf(tmp, sizeof(tmp), " [s%d]", i); 291 strlcat(state->pp_buf, tmp, PAGE_SIZE); 292 /* solaris partitions are relative to current MS-DOS 293 * one; must add the offset of the current partition */ 294 put_partition(state, state->next++, 295 le32_to_cpu(s->s_start)+offset, 296 le32_to_cpu(s->s_size)); 297 } 298 put_dev_sector(sect); 299 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 300 #endif 301 } 302 303 /* check against BSD src/sys/sys/disklabel.h for consistency */ 304 #define BSD_DISKMAGIC (0x82564557UL) /* The disk magic number */ 305 #define BSD_MAXPARTITIONS 16 306 #define OPENBSD_MAXPARTITIONS 16 307 #define BSD_FS_UNUSED 0 /* disklabel unused partition entry ID */ 308 struct bsd_disklabel { 309 __le32 d_magic; /* the magic number */ 310 __s16 d_type; /* drive type */ 311 __s16 d_subtype; /* controller/d_type specific */ 312 char d_typename[16]; /* type name, e.g. "eagle" */ 313 char d_packname[16]; /* pack identifier */ 314 __u32 d_secsize; /* # of bytes per sector */ 315 __u32 d_nsectors; /* # of data sectors per track */ 316 __u32 d_ntracks; /* # of tracks per cylinder */ 317 __u32 d_ncylinders; /* # of data cylinders per unit */ 318 __u32 d_secpercyl; /* # of data sectors per cylinder */ 319 __u32 d_secperunit; /* # of data sectors per unit */ 320 __u16 d_sparespertrack; /* # of spare sectors per track */ 321 __u16 d_sparespercyl; /* # of spare sectors per cylinder */ 322 __u32 d_acylinders; /* # of alt. cylinders per unit */ 323 __u16 d_rpm; /* rotational speed */ 324 __u16 d_interleave; /* hardware sector interleave */ 325 __u16 d_trackskew; /* sector 0 skew, per track */ 326 __u16 d_cylskew; /* sector 0 skew, per cylinder */ 327 __u32 d_headswitch; /* head switch time, usec */ 328 __u32 d_trkseek; /* track-to-track seek, usec */ 329 __u32 d_flags; /* generic flags */ 330 #define NDDATA 5 331 __u32 d_drivedata[NDDATA]; /* drive-type specific information */ 332 #define NSPARE 5 333 __u32 d_spare[NSPARE]; /* reserved for future use */ 334 __le32 d_magic2; /* the magic number (again) */ 335 __le16 d_checksum; /* xor of data incl. partitions */ 336 337 /* filesystem and partition information: */ 338 __le16 d_npartitions; /* number of partitions in following */ 339 __le32 d_bbsize; /* size of boot area at sn0, bytes */ 340 __le32 d_sbsize; /* max size of fs superblock, bytes */ 341 struct bsd_partition { /* the partition table */ 342 __le32 p_size; /* number of sectors in partition */ 343 __le32 p_offset; /* starting sector */ 344 __le32 p_fsize; /* filesystem basic fragment size */ 345 __u8 p_fstype; /* filesystem type, see below */ 346 __u8 p_frag; /* filesystem fragments per block */ 347 __le16 p_cpg; /* filesystem cylinders per group */ 348 } d_partitions[BSD_MAXPARTITIONS]; /* actually may be more */ 349 }; 350 351 #if defined(CONFIG_BSD_DISKLABEL) 352 /* 353 * Create devices for BSD partitions listed in a disklabel, under a 354 * dos-like partition. See parse_extended() for more information. 355 */ 356 static void parse_bsd(struct parsed_partitions *state, 357 sector_t offset, sector_t size, int origin, char *flavour, 358 int max_partitions) 359 { 360 Sector sect; 361 struct bsd_disklabel *l; 362 struct bsd_partition *p; 363 char tmp[64]; 364 365 l = read_part_sector(state, offset + 1, §); 366 if (!l) 367 return; 368 if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) { 369 put_dev_sector(sect); 370 return; 371 } 372 373 snprintf(tmp, sizeof(tmp), " %s%d: <%s:", state->name, origin, flavour); 374 strlcat(state->pp_buf, tmp, PAGE_SIZE); 375 376 if (le16_to_cpu(l->d_npartitions) < max_partitions) 377 max_partitions = le16_to_cpu(l->d_npartitions); 378 for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) { 379 sector_t bsd_start, bsd_size; 380 381 if (state->next == state->limit) 382 break; 383 if (p->p_fstype == BSD_FS_UNUSED) 384 continue; 385 bsd_start = le32_to_cpu(p->p_offset); 386 bsd_size = le32_to_cpu(p->p_size); 387 /* FreeBSD has relative offset if C partition offset is zero */ 388 if (memcmp(flavour, "bsd\0", 4) == 0 && 389 le32_to_cpu(l->d_partitions[2].p_offset) == 0) 390 bsd_start += offset; 391 if (offset == bsd_start && size == bsd_size) 392 /* full parent partition, we have it already */ 393 continue; 394 if (offset > bsd_start || offset+size < bsd_start+bsd_size) { 395 strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE); 396 continue; 397 } 398 put_partition(state, state->next++, bsd_start, bsd_size); 399 } 400 put_dev_sector(sect); 401 if (le16_to_cpu(l->d_npartitions) > max_partitions) { 402 snprintf(tmp, sizeof(tmp), " (ignored %d more)", 403 le16_to_cpu(l->d_npartitions) - max_partitions); 404 strlcat(state->pp_buf, tmp, PAGE_SIZE); 405 } 406 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 407 } 408 #endif 409 410 static void parse_freebsd(struct parsed_partitions *state, 411 sector_t offset, sector_t size, int origin) 412 { 413 #ifdef CONFIG_BSD_DISKLABEL 414 parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS); 415 #endif 416 } 417 418 static void parse_netbsd(struct parsed_partitions *state, 419 sector_t offset, sector_t size, int origin) 420 { 421 #ifdef CONFIG_BSD_DISKLABEL 422 parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS); 423 #endif 424 } 425 426 static void parse_openbsd(struct parsed_partitions *state, 427 sector_t offset, sector_t size, int origin) 428 { 429 #ifdef CONFIG_BSD_DISKLABEL 430 parse_bsd(state, offset, size, origin, "openbsd", 431 OPENBSD_MAXPARTITIONS); 432 #endif 433 } 434 435 #define UNIXWARE_DISKMAGIC (0xCA5E600DUL) /* The disk magic number */ 436 #define UNIXWARE_DISKMAGIC2 (0x600DDEEEUL) /* The slice table magic nr */ 437 #define UNIXWARE_NUMSLICE 16 438 #define UNIXWARE_FS_UNUSED 0 /* Unused slice entry ID */ 439 440 struct unixware_slice { 441 __le16 s_label; /* label */ 442 __le16 s_flags; /* permission flags */ 443 __le32 start_sect; /* starting sector */ 444 __le32 nr_sects; /* number of sectors in slice */ 445 }; 446 447 struct unixware_disklabel { 448 __le32 d_type; /* drive type */ 449 __le32 d_magic; /* the magic number */ 450 __le32 d_version; /* version number */ 451 char d_serial[12]; /* serial number of the device */ 452 __le32 d_ncylinders; /* # of data cylinders per device */ 453 __le32 d_ntracks; /* # of tracks per cylinder */ 454 __le32 d_nsectors; /* # of data sectors per track */ 455 __le32 d_secsize; /* # of bytes per sector */ 456 __le32 d_part_start; /* # of first sector of this partition*/ 457 __le32 d_unknown1[12]; /* ? */ 458 __le32 d_alt_tbl; /* byte offset of alternate table */ 459 __le32 d_alt_len; /* byte length of alternate table */ 460 __le32 d_phys_cyl; /* # of physical cylinders per device */ 461 __le32 d_phys_trk; /* # of physical tracks per cylinder */ 462 __le32 d_phys_sec; /* # of physical sectors per track */ 463 __le32 d_phys_bytes; /* # of physical bytes per sector */ 464 __le32 d_unknown2; /* ? */ 465 __le32 d_unknown3; /* ? */ 466 __le32 d_pad[8]; /* pad */ 467 468 struct unixware_vtoc { 469 __le32 v_magic; /* the magic number */ 470 __le32 v_version; /* version number */ 471 char v_name[8]; /* volume name */ 472 __le16 v_nslices; /* # of slices */ 473 __le16 v_unknown1; /* ? */ 474 __le32 v_reserved[10]; /* reserved */ 475 struct unixware_slice 476 v_slice[UNIXWARE_NUMSLICE]; /* slice headers */ 477 } vtoc; 478 }; /* 408 */ 479 480 /* 481 * Create devices for Unixware partitions listed in a disklabel, under a 482 * dos-like partition. See parse_extended() for more information. 483 */ 484 static void parse_unixware(struct parsed_partitions *state, 485 sector_t offset, sector_t size, int origin) 486 { 487 #ifdef CONFIG_UNIXWARE_DISKLABEL 488 Sector sect; 489 struct unixware_disklabel *l; 490 struct unixware_slice *p; 491 492 l = read_part_sector(state, offset + 29, §); 493 if (!l) 494 return; 495 if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC || 496 le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) { 497 put_dev_sector(sect); 498 return; 499 } 500 { 501 char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1]; 502 503 snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin); 504 strlcat(state->pp_buf, tmp, PAGE_SIZE); 505 } 506 p = &l->vtoc.v_slice[1]; 507 /* I omit the 0th slice as it is the same as whole disk. */ 508 while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) { 509 if (state->next == state->limit) 510 break; 511 512 if (p->s_label != UNIXWARE_FS_UNUSED) 513 put_partition(state, state->next++, 514 le32_to_cpu(p->start_sect), 515 le32_to_cpu(p->nr_sects)); 516 p++; 517 } 518 put_dev_sector(sect); 519 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 520 #endif 521 } 522 523 #define MINIX_NR_SUBPARTITIONS 4 524 525 /* 526 * Minix 2.0.0/2.0.2 subpartition support. 527 * Anand Krishnamurthy <anandk@wiproge.med.ge.com> 528 * Rajeev V. Pillai <rajeevvp@yahoo.com> 529 */ 530 static void parse_minix(struct parsed_partitions *state, 531 sector_t offset, sector_t size, int origin) 532 { 533 #ifdef CONFIG_MINIX_SUBPARTITION 534 Sector sect; 535 unsigned char *data; 536 struct msdos_partition *p; 537 int i; 538 539 data = read_part_sector(state, offset, §); 540 if (!data) 541 return; 542 543 p = (struct msdos_partition *)(data + 0x1be); 544 545 /* The first sector of a Minix partition can have either 546 * a secondary MBR describing its subpartitions, or 547 * the normal boot sector. */ 548 if (msdos_magic_present(data + 510) && 549 SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */ 550 char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1]; 551 552 snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin); 553 strlcat(state->pp_buf, tmp, PAGE_SIZE); 554 for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) { 555 if (state->next == state->limit) 556 break; 557 /* add each partition in use */ 558 if (SYS_IND(p) == MINIX_PARTITION) 559 put_partition(state, state->next++, 560 start_sect(p), nr_sects(p)); 561 } 562 strlcat(state->pp_buf, " >\n", PAGE_SIZE); 563 } 564 put_dev_sector(sect); 565 #endif /* CONFIG_MINIX_SUBPARTITION */ 566 } 567 568 static struct { 569 unsigned char id; 570 void (*parse)(struct parsed_partitions *, sector_t, sector_t, int); 571 } subtypes[] = { 572 {FREEBSD_PARTITION, parse_freebsd}, 573 {NETBSD_PARTITION, parse_netbsd}, 574 {OPENBSD_PARTITION, parse_openbsd}, 575 {MINIX_PARTITION, parse_minix}, 576 {UNIXWARE_PARTITION, parse_unixware}, 577 {SOLARIS_X86_PARTITION, parse_solaris_x86}, 578 {NEW_SOLARIS_X86_PARTITION, parse_solaris_x86}, 579 {0, NULL}, 580 }; 581 582 int msdos_partition(struct parsed_partitions *state) 583 { 584 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512; 585 Sector sect; 586 unsigned char *data; 587 struct msdos_partition *p; 588 struct fat_boot_sector *fb; 589 int slot; 590 u32 disksig; 591 592 data = read_part_sector(state, 0, §); 593 if (!data) 594 return -1; 595 596 /* 597 * Note order! (some AIX disks, e.g. unbootable kind, 598 * have no MSDOS 55aa) 599 */ 600 if (aix_magic_present(state, data)) { 601 put_dev_sector(sect); 602 #ifdef CONFIG_AIX_PARTITION 603 return aix_partition(state); 604 #else 605 strlcat(state->pp_buf, " [AIX]", PAGE_SIZE); 606 return 0; 607 #endif 608 } 609 610 if (!msdos_magic_present(data + 510)) { 611 put_dev_sector(sect); 612 return 0; 613 } 614 615 /* 616 * Now that the 55aa signature is present, this is probably 617 * either the boot sector of a FAT filesystem or a DOS-type 618 * partition table. Reject this in case the boot indicator 619 * is not 0 or 0x80. 620 */ 621 p = (struct msdos_partition *) (data + 0x1be); 622 for (slot = 1; slot <= 4; slot++, p++) { 623 if (p->boot_ind != 0 && p->boot_ind != 0x80) { 624 /* 625 * Even without a valid boot inidicator value 626 * its still possible this is valid FAT filesystem 627 * without a partition table. 628 */ 629 fb = (struct fat_boot_sector *) data; 630 if (slot == 1 && fb->reserved && fb->fats 631 && fat_valid_media(fb->media)) { 632 strlcat(state->pp_buf, "\n", PAGE_SIZE); 633 put_dev_sector(sect); 634 return 1; 635 } else { 636 put_dev_sector(sect); 637 return 0; 638 } 639 } 640 } 641 642 #ifdef CONFIG_EFI_PARTITION 643 p = (struct msdos_partition *) (data + 0x1be); 644 for (slot = 1 ; slot <= 4 ; slot++, p++) { 645 /* If this is an EFI GPT disk, msdos should ignore it. */ 646 if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) { 647 put_dev_sector(sect); 648 return 0; 649 } 650 } 651 #endif 652 p = (struct msdos_partition *) (data + 0x1be); 653 654 disksig = le32_to_cpup((__le32 *)(data + 0x1b8)); 655 656 /* 657 * Look for partitions in two passes: 658 * First find the primary and DOS-type extended partitions. 659 * On the second pass look inside *BSD, Unixware and Solaris partitions. 660 */ 661 662 state->next = 5; 663 for (slot = 1 ; slot <= 4 ; slot++, p++) { 664 sector_t start = start_sect(p)*sector_size; 665 sector_t size = nr_sects(p)*sector_size; 666 667 if (!size) 668 continue; 669 if (is_extended_partition(p)) { 670 /* 671 * prevent someone doing mkfs or mkswap on an 672 * extended partition, but leave room for LILO 673 * FIXME: this uses one logical sector for > 512b 674 * sector, although it may not be enough/proper. 675 */ 676 sector_t n = 2; 677 678 n = min(size, max(sector_size, n)); 679 put_partition(state, slot, start, n); 680 681 strlcat(state->pp_buf, " <", PAGE_SIZE); 682 parse_extended(state, start, size, disksig); 683 strlcat(state->pp_buf, " >", PAGE_SIZE); 684 continue; 685 } 686 put_partition(state, slot, start, size); 687 set_info(state, slot, disksig); 688 if (SYS_IND(p) == LINUX_RAID_PARTITION) 689 state->parts[slot].flags = ADDPART_FLAG_RAID; 690 if (SYS_IND(p) == DM6_PARTITION) 691 strlcat(state->pp_buf, "[DM]", PAGE_SIZE); 692 if (SYS_IND(p) == EZD_PARTITION) 693 strlcat(state->pp_buf, "[EZD]", PAGE_SIZE); 694 } 695 696 strlcat(state->pp_buf, "\n", PAGE_SIZE); 697 698 /* second pass - output for each on a separate line */ 699 p = (struct msdos_partition *) (0x1be + data); 700 for (slot = 1 ; slot <= 4 ; slot++, p++) { 701 unsigned char id = SYS_IND(p); 702 int n; 703 704 if (!nr_sects(p)) 705 continue; 706 707 for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++) 708 ; 709 710 if (!subtypes[n].parse) 711 continue; 712 subtypes[n].parse(state, start_sect(p) * sector_size, 713 nr_sects(p) * sector_size, slot); 714 } 715 put_dev_sector(sect); 716 return 1; 717 } 718