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
nr_sects(struct partition * p)37 static inline sector_t nr_sects(struct partition *p)
38 {
39 return (sector_t)get_unaligned_le32(&p->nr_sects);
40 }
41
start_sect(struct partition * p)42 static inline sector_t start_sect(struct partition *p)
43 {
44 return (sector_t)get_unaligned_le32(&p->start_sect);
45 }
46
is_extended_partition(struct partition * p)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
msdos_magic_present(unsigned char * p)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
aix_magic_present(struct parsed_partitions * state,unsigned char * p)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
set_info(struct parsed_partitions * state,int slot,u32 disksig)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
parse_extended(struct parsed_partitions * state,sector_t first_sector,sector_t first_size,u32 disksig)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
parse_solaris_x86(struct parsed_partitions * state,sector_t offset,sector_t size,int origin)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 */
parse_bsd(struct parsed_partitions * state,sector_t offset,sector_t size,int origin,char * flavour,int max_partitions)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 /* FreeBSD has relative offset if C partition offset is zero */
304 if (memcmp(flavour, "bsd\0", 4) == 0 &&
305 le32_to_cpu(l->d_partitions[2].p_offset) == 0)
306 bsd_start += offset;
307 if (offset == bsd_start && size == bsd_size)
308 /* full parent partition, we have it already */
309 continue;
310 if (offset > bsd_start || offset+size < bsd_start+bsd_size) {
311 strlcat(state->pp_buf, "bad subpartition - ignored\n", PAGE_SIZE);
312 continue;
313 }
314 put_partition(state, state->next++, bsd_start, bsd_size);
315 }
316 put_dev_sector(sect);
317 if (le16_to_cpu(l->d_npartitions) > max_partitions) {
318 snprintf(tmp, sizeof(tmp), " (ignored %d more)",
319 le16_to_cpu(l->d_npartitions) - max_partitions);
320 strlcat(state->pp_buf, tmp, PAGE_SIZE);
321 }
322 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
323 }
324 #endif
325
parse_freebsd(struct parsed_partitions * state,sector_t offset,sector_t size,int origin)326 static void parse_freebsd(struct parsed_partitions *state,
327 sector_t offset, sector_t size, int origin)
328 {
329 #ifdef CONFIG_BSD_DISKLABEL
330 parse_bsd(state, offset, size, origin, "bsd", BSD_MAXPARTITIONS);
331 #endif
332 }
333
parse_netbsd(struct parsed_partitions * state,sector_t offset,sector_t size,int origin)334 static void parse_netbsd(struct parsed_partitions *state,
335 sector_t offset, sector_t size, int origin)
336 {
337 #ifdef CONFIG_BSD_DISKLABEL
338 parse_bsd(state, offset, size, origin, "netbsd", BSD_MAXPARTITIONS);
339 #endif
340 }
341
parse_openbsd(struct parsed_partitions * state,sector_t offset,sector_t size,int origin)342 static void parse_openbsd(struct parsed_partitions *state,
343 sector_t offset, sector_t size, int origin)
344 {
345 #ifdef CONFIG_BSD_DISKLABEL
346 parse_bsd(state, offset, size, origin, "openbsd",
347 OPENBSD_MAXPARTITIONS);
348 #endif
349 }
350
351 /*
352 * Create devices for Unixware partitions listed in a disklabel, under a
353 * dos-like partition. See parse_extended() for more information.
354 */
parse_unixware(struct parsed_partitions * state,sector_t offset,sector_t size,int origin)355 static void parse_unixware(struct parsed_partitions *state,
356 sector_t offset, sector_t size, int origin)
357 {
358 #ifdef CONFIG_UNIXWARE_DISKLABEL
359 Sector sect;
360 struct unixware_disklabel *l;
361 struct unixware_slice *p;
362
363 l = read_part_sector(state, offset + 29, §);
364 if (!l)
365 return;
366 if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC ||
367 le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) {
368 put_dev_sector(sect);
369 return;
370 }
371 {
372 char tmp[1 + BDEVNAME_SIZE + 10 + 12 + 1];
373
374 snprintf(tmp, sizeof(tmp), " %s%d: <unixware:", state->name, origin);
375 strlcat(state->pp_buf, tmp, PAGE_SIZE);
376 }
377 p = &l->vtoc.v_slice[1];
378 /* I omit the 0th slice as it is the same as whole disk. */
379 while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) {
380 if (state->next == state->limit)
381 break;
382
383 if (p->s_label != UNIXWARE_FS_UNUSED)
384 put_partition(state, state->next++,
385 le32_to_cpu(p->start_sect),
386 le32_to_cpu(p->nr_sects));
387 p++;
388 }
389 put_dev_sector(sect);
390 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
391 #endif
392 }
393
394 /*
395 * Minix 2.0.0/2.0.2 subpartition support.
396 * Anand Krishnamurthy <anandk@wiproge.med.ge.com>
397 * Rajeev V. Pillai <rajeevvp@yahoo.com>
398 */
parse_minix(struct parsed_partitions * state,sector_t offset,sector_t size,int origin)399 static void parse_minix(struct parsed_partitions *state,
400 sector_t offset, sector_t size, int origin)
401 {
402 #ifdef CONFIG_MINIX_SUBPARTITION
403 Sector sect;
404 unsigned char *data;
405 struct partition *p;
406 int i;
407
408 data = read_part_sector(state, offset, §);
409 if (!data)
410 return;
411
412 p = (struct partition *)(data + 0x1be);
413
414 /* The first sector of a Minix partition can have either
415 * a secondary MBR describing its subpartitions, or
416 * the normal boot sector. */
417 if (msdos_magic_present(data + 510) &&
418 SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */
419 char tmp[1 + BDEVNAME_SIZE + 10 + 9 + 1];
420
421 snprintf(tmp, sizeof(tmp), " %s%d: <minix:", state->name, origin);
422 strlcat(state->pp_buf, tmp, PAGE_SIZE);
423 for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) {
424 if (state->next == state->limit)
425 break;
426 /* add each partition in use */
427 if (SYS_IND(p) == MINIX_PARTITION)
428 put_partition(state, state->next++,
429 start_sect(p), nr_sects(p));
430 }
431 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
432 }
433 put_dev_sector(sect);
434 #endif /* CONFIG_MINIX_SUBPARTITION */
435 }
436
437 static struct {
438 unsigned char id;
439 void (*parse)(struct parsed_partitions *, sector_t, sector_t, int);
440 } subtypes[] = {
441 {FREEBSD_PARTITION, parse_freebsd},
442 {NETBSD_PARTITION, parse_netbsd},
443 {OPENBSD_PARTITION, parse_openbsd},
444 {MINIX_PARTITION, parse_minix},
445 {UNIXWARE_PARTITION, parse_unixware},
446 {SOLARIS_X86_PARTITION, parse_solaris_x86},
447 {NEW_SOLARIS_X86_PARTITION, parse_solaris_x86},
448 {0, NULL},
449 };
450
msdos_partition(struct parsed_partitions * state)451 int msdos_partition(struct parsed_partitions *state)
452 {
453 sector_t sector_size = bdev_logical_block_size(state->bdev) / 512;
454 Sector sect;
455 unsigned char *data;
456 struct partition *p;
457 struct fat_boot_sector *fb;
458 int slot;
459 u32 disksig;
460
461 data = read_part_sector(state, 0, §);
462 if (!data)
463 return -1;
464
465 /*
466 * Note order! (some AIX disks, e.g. unbootable kind,
467 * have no MSDOS 55aa)
468 */
469 if (aix_magic_present(state, data)) {
470 put_dev_sector(sect);
471 #ifdef CONFIG_AIX_PARTITION
472 return aix_partition(state);
473 #else
474 strlcat(state->pp_buf, " [AIX]", PAGE_SIZE);
475 return 0;
476 #endif
477 }
478
479 if (!msdos_magic_present(data + 510)) {
480 put_dev_sector(sect);
481 return 0;
482 }
483
484 /*
485 * Now that the 55aa signature is present, this is probably
486 * either the boot sector of a FAT filesystem or a DOS-type
487 * partition table. Reject this in case the boot indicator
488 * is not 0 or 0x80.
489 */
490 p = (struct partition *) (data + 0x1be);
491 for (slot = 1; slot <= 4; slot++, p++) {
492 if (p->boot_ind != 0 && p->boot_ind != 0x80) {
493 /*
494 * Even without a valid boot inidicator value
495 * its still possible this is valid FAT filesystem
496 * without a partition table.
497 */
498 fb = (struct fat_boot_sector *) data;
499 if (slot == 1 && fb->reserved && fb->fats
500 && fat_valid_media(fb->media)) {
501 strlcat(state->pp_buf, "\n", PAGE_SIZE);
502 put_dev_sector(sect);
503 return 1;
504 } else {
505 put_dev_sector(sect);
506 return 0;
507 }
508 }
509 }
510
511 #ifdef CONFIG_EFI_PARTITION
512 p = (struct partition *) (data + 0x1be);
513 for (slot = 1 ; slot <= 4 ; slot++, p++) {
514 /* If this is an EFI GPT disk, msdos should ignore it. */
515 if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) {
516 put_dev_sector(sect);
517 return 0;
518 }
519 }
520 #endif
521 p = (struct partition *) (data + 0x1be);
522
523 disksig = le32_to_cpup((__le32 *)(data + 0x1b8));
524
525 /*
526 * Look for partitions in two passes:
527 * First find the primary and DOS-type extended partitions.
528 * On the second pass look inside *BSD, Unixware and Solaris partitions.
529 */
530
531 state->next = 5;
532 for (slot = 1 ; slot <= 4 ; slot++, p++) {
533 sector_t start = start_sect(p)*sector_size;
534 sector_t size = nr_sects(p)*sector_size;
535
536 if (!size)
537 continue;
538 if (is_extended_partition(p)) {
539 /*
540 * prevent someone doing mkfs or mkswap on an
541 * extended partition, but leave room for LILO
542 * FIXME: this uses one logical sector for > 512b
543 * sector, although it may not be enough/proper.
544 */
545 sector_t n = 2;
546
547 n = min(size, max(sector_size, n));
548 put_partition(state, slot, start, n);
549
550 strlcat(state->pp_buf, " <", PAGE_SIZE);
551 parse_extended(state, start, size, disksig);
552 strlcat(state->pp_buf, " >", PAGE_SIZE);
553 continue;
554 }
555 put_partition(state, slot, start, size);
556 set_info(state, slot, disksig);
557 if (SYS_IND(p) == LINUX_RAID_PARTITION)
558 state->parts[slot].flags = ADDPART_FLAG_RAID;
559 if (SYS_IND(p) == DM6_PARTITION)
560 strlcat(state->pp_buf, "[DM]", PAGE_SIZE);
561 if (SYS_IND(p) == EZD_PARTITION)
562 strlcat(state->pp_buf, "[EZD]", PAGE_SIZE);
563 }
564
565 strlcat(state->pp_buf, "\n", PAGE_SIZE);
566
567 /* second pass - output for each on a separate line */
568 p = (struct partition *) (0x1be + data);
569 for (slot = 1 ; slot <= 4 ; slot++, p++) {
570 unsigned char id = SYS_IND(p);
571 int n;
572
573 if (!nr_sects(p))
574 continue;
575
576 for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++)
577 ;
578
579 if (!subtypes[n].parse)
580 continue;
581 subtypes[n].parse(state, start_sect(p) * sector_size,
582 nr_sects(p) * sector_size, slot);
583 }
584 put_dev_sector(sect);
585 return 1;
586 }
587