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1da177e4 LT |
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 | ||
22 | #include <linux/config.h> | |
23 | ||
24 | #include "check.h" | |
25 | #include "msdos.h" | |
26 | #include "efi.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 | #define NR_SECTS(p) ({ __typeof__(p->nr_sects) __a = \ | |
37 | get_unaligned(&p->nr_sects); \ | |
38 | le32_to_cpu(__a); \ | |
39 | }) | |
40 | ||
41 | #define START_SECT(p) ({ __typeof__(p->start_sect) __a = \ | |
42 | get_unaligned(&p->start_sect); \ | |
43 | le32_to_cpu(__a); \ | |
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 | /* | |
63 | * Create devices for each logical partition in an extended partition. | |
64 | * The logical partitions form a linked list, with each entry being | |
65 | * a partition table with two entries. The first entry | |
66 | * is the real data partition (with a start relative to the partition | |
67 | * table start). The second is a pointer to the next logical partition | |
68 | * (with a start relative to the entire extended partition). | |
69 | * We do not create a Linux partition for the partition tables, but | |
70 | * only for the actual data partitions. | |
71 | */ | |
72 | ||
73 | static void | |
74 | parse_extended(struct parsed_partitions *state, struct block_device *bdev, | |
75 | u32 first_sector, u32 first_size) | |
76 | { | |
77 | struct partition *p; | |
78 | Sector sect; | |
79 | unsigned char *data; | |
80 | u32 this_sector, this_size; | |
81 | int sector_size = bdev_hardsect_size(bdev) / 512; | |
82 | int loopct = 0; /* number of links followed | |
83 | without finding a data partition */ | |
84 | int i; | |
85 | ||
86 | this_sector = first_sector; | |
87 | this_size = first_size; | |
88 | ||
89 | while (1) { | |
90 | if (++loopct > 100) | |
91 | return; | |
92 | if (state->next == state->limit) | |
93 | return; | |
94 | data = read_dev_sector(bdev, this_sector, §); | |
95 | if (!data) | |
96 | return; | |
97 | ||
98 | if (!msdos_magic_present(data + 510)) | |
99 | goto done; | |
100 | ||
101 | p = (struct partition *) (data + 0x1be); | |
102 | ||
103 | /* | |
104 | * Usually, the first entry is the real data partition, | |
105 | * the 2nd entry is the next extended partition, or empty, | |
106 | * and the 3rd and 4th entries are unused. | |
107 | * However, DRDOS sometimes has the extended partition as | |
108 | * the first entry (when the data partition is empty), | |
109 | * and OS/2 seems to use all four entries. | |
110 | */ | |
111 | ||
112 | /* | |
113 | * First process the data partition(s) | |
114 | */ | |
115 | for (i=0; i<4; i++, p++) { | |
116 | u32 offs, size, next; | |
117 | ||
118 | if (SYS_IND(p) == 0) | |
119 | continue; | |
120 | if (!NR_SECTS(p) || is_extended_partition(p)) | |
121 | continue; | |
122 | ||
123 | /* Check the 3rd and 4th entries - | |
124 | these sometimes contain random garbage */ | |
125 | offs = START_SECT(p)*sector_size; | |
126 | size = NR_SECTS(p)*sector_size; | |
127 | next = this_sector + offs; | |
128 | if (i >= 2) { | |
129 | if (offs + size > this_size) | |
130 | continue; | |
131 | if (next < first_sector) | |
132 | continue; | |
133 | if (next + size > first_sector + first_size) | |
134 | continue; | |
135 | } | |
136 | ||
137 | put_partition(state, state->next, next, size); | |
138 | if (SYS_IND(p) == LINUX_RAID_PARTITION) | |
139 | state->parts[state->next].flags = 1; | |
140 | loopct = 0; | |
141 | if (++state->next == state->limit) | |
142 | goto done; | |
143 | } | |
144 | /* | |
145 | * Next, process the (first) extended partition, if present. | |
146 | * (So far, there seems to be no reason to make | |
147 | * parse_extended() recursive and allow a tree | |
148 | * of extended partitions.) | |
149 | * It should be a link to the next logical partition. | |
150 | */ | |
151 | p -= 4; | |
152 | for (i=0; i<4; i++, p++) | |
153 | if (NR_SECTS(p) && is_extended_partition(p)) | |
154 | break; | |
155 | if (i == 4) | |
156 | goto done; /* nothing left to do */ | |
157 | ||
158 | this_sector = first_sector + START_SECT(p) * sector_size; | |
159 | this_size = NR_SECTS(p) * sector_size; | |
160 | put_dev_sector(sect); | |
161 | } | |
162 | done: | |
163 | put_dev_sector(sect); | |
164 | } | |
165 | ||
166 | /* james@bpgc.com: Solaris has a nasty indicator: 0x82 which also | |
167 | indicates linux swap. Be careful before believing this is Solaris. */ | |
168 | ||
169 | static void | |
170 | parse_solaris_x86(struct parsed_partitions *state, struct block_device *bdev, | |
171 | u32 offset, u32 size, int origin) | |
172 | { | |
173 | #ifdef CONFIG_SOLARIS_X86_PARTITION | |
174 | Sector sect; | |
175 | struct solaris_x86_vtoc *v; | |
176 | int i; | |
177 | ||
178 | v = (struct solaris_x86_vtoc *)read_dev_sector(bdev, offset+1, §); | |
179 | if (!v) | |
180 | return; | |
181 | if (le32_to_cpu(v->v_sanity) != SOLARIS_X86_VTOC_SANE) { | |
182 | put_dev_sector(sect); | |
183 | return; | |
184 | } | |
185 | printk(" %s%d: <solaris:", state->name, origin); | |
186 | if (le32_to_cpu(v->v_version) != 1) { | |
187 | printk(" cannot handle version %d vtoc>\n", | |
188 | le32_to_cpu(v->v_version)); | |
189 | put_dev_sector(sect); | |
190 | return; | |
191 | } | |
192 | for (i=0; i<SOLARIS_X86_NUMSLICE && state->next<state->limit; i++) { | |
193 | struct solaris_x86_slice *s = &v->v_slice[i]; | |
194 | if (s->s_size == 0) | |
195 | continue; | |
196 | printk(" [s%d]", i); | |
197 | /* solaris partitions are relative to current MS-DOS | |
198 | * one; must add the offset of the current partition */ | |
199 | put_partition(state, state->next++, | |
200 | le32_to_cpu(s->s_start)+offset, | |
201 | le32_to_cpu(s->s_size)); | |
202 | } | |
203 | put_dev_sector(sect); | |
204 | printk(" >\n"); | |
205 | #endif | |
206 | } | |
207 | ||
208 | #if defined(CONFIG_BSD_DISKLABEL) || defined(CONFIG_NEC98_PARTITION) | |
209 | /* | |
210 | * Create devices for BSD partitions listed in a disklabel, under a | |
211 | * dos-like partition. See parse_extended() for more information. | |
212 | */ | |
213 | void | |
214 | parse_bsd(struct parsed_partitions *state, struct block_device *bdev, | |
215 | u32 offset, u32 size, int origin, char *flavour, | |
216 | int max_partitions) | |
217 | { | |
218 | Sector sect; | |
219 | struct bsd_disklabel *l; | |
220 | struct bsd_partition *p; | |
221 | ||
222 | l = (struct bsd_disklabel *)read_dev_sector(bdev, offset+1, §); | |
223 | if (!l) | |
224 | return; | |
225 | if (le32_to_cpu(l->d_magic) != BSD_DISKMAGIC) { | |
226 | put_dev_sector(sect); | |
227 | return; | |
228 | } | |
229 | printk(" %s%d: <%s:", state->name, origin, flavour); | |
230 | ||
231 | if (le16_to_cpu(l->d_npartitions) < max_partitions) | |
232 | max_partitions = le16_to_cpu(l->d_npartitions); | |
233 | for (p = l->d_partitions; p - l->d_partitions < max_partitions; p++) { | |
234 | u32 bsd_start, bsd_size; | |
235 | ||
236 | if (state->next == state->limit) | |
237 | break; | |
238 | if (p->p_fstype == BSD_FS_UNUSED) | |
239 | continue; | |
240 | bsd_start = le32_to_cpu(p->p_offset); | |
241 | bsd_size = le32_to_cpu(p->p_size); | |
242 | if (offset == bsd_start && size == bsd_size) | |
243 | /* full parent partition, we have it already */ | |
244 | continue; | |
245 | if (offset > bsd_start || offset+size < bsd_start+bsd_size) { | |
246 | printk("bad subpartition - ignored\n"); | |
247 | continue; | |
248 | } | |
249 | put_partition(state, state->next++, bsd_start, bsd_size); | |
250 | } | |
251 | put_dev_sector(sect); | |
252 | if (le16_to_cpu(l->d_npartitions) > max_partitions) | |
253 | printk(" (ignored %d more)", | |
254 | le16_to_cpu(l->d_npartitions) - max_partitions); | |
255 | printk(" >\n"); | |
256 | } | |
257 | #endif | |
258 | ||
259 | static void | |
260 | parse_freebsd(struct parsed_partitions *state, struct block_device *bdev, | |
261 | u32 offset, u32 size, int origin) | |
262 | { | |
263 | #ifdef CONFIG_BSD_DISKLABEL | |
264 | parse_bsd(state, bdev, offset, size, origin, | |
265 | "bsd", BSD_MAXPARTITIONS); | |
266 | #endif | |
267 | } | |
268 | ||
269 | static void | |
270 | parse_netbsd(struct parsed_partitions *state, struct block_device *bdev, | |
271 | u32 offset, u32 size, int origin) | |
272 | { | |
273 | #ifdef CONFIG_BSD_DISKLABEL | |
274 | parse_bsd(state, bdev, offset, size, origin, | |
275 | "netbsd", BSD_MAXPARTITIONS); | |
276 | #endif | |
277 | } | |
278 | ||
279 | static void | |
280 | parse_openbsd(struct parsed_partitions *state, struct block_device *bdev, | |
281 | u32 offset, u32 size, int origin) | |
282 | { | |
283 | #ifdef CONFIG_BSD_DISKLABEL | |
284 | parse_bsd(state, bdev, offset, size, origin, | |
285 | "openbsd", OPENBSD_MAXPARTITIONS); | |
286 | #endif | |
287 | } | |
288 | ||
289 | /* | |
290 | * Create devices for Unixware partitions listed in a disklabel, under a | |
291 | * dos-like partition. See parse_extended() for more information. | |
292 | */ | |
293 | static void | |
294 | parse_unixware(struct parsed_partitions *state, struct block_device *bdev, | |
295 | u32 offset, u32 size, int origin) | |
296 | { | |
297 | #ifdef CONFIG_UNIXWARE_DISKLABEL | |
298 | Sector sect; | |
299 | struct unixware_disklabel *l; | |
300 | struct unixware_slice *p; | |
301 | ||
302 | l = (struct unixware_disklabel *)read_dev_sector(bdev, offset+29, §); | |
303 | if (!l) | |
304 | return; | |
305 | if (le32_to_cpu(l->d_magic) != UNIXWARE_DISKMAGIC || | |
306 | le32_to_cpu(l->vtoc.v_magic) != UNIXWARE_DISKMAGIC2) { | |
307 | put_dev_sector(sect); | |
308 | return; | |
309 | } | |
310 | printk(" %s%d: <unixware:", state->name, origin); | |
311 | p = &l->vtoc.v_slice[1]; | |
312 | /* I omit the 0th slice as it is the same as whole disk. */ | |
313 | while (p - &l->vtoc.v_slice[0] < UNIXWARE_NUMSLICE) { | |
314 | if (state->next == state->limit) | |
315 | break; | |
316 | ||
317 | if (p->s_label != UNIXWARE_FS_UNUSED) | |
318 | put_partition(state, state->next++, | |
319 | START_SECT(p), NR_SECTS(p)); | |
320 | p++; | |
321 | } | |
322 | put_dev_sector(sect); | |
323 | printk(" >\n"); | |
324 | #endif | |
325 | } | |
326 | ||
327 | /* | |
328 | * Minix 2.0.0/2.0.2 subpartition support. | |
329 | * Anand Krishnamurthy <anandk@wiproge.med.ge.com> | |
330 | * Rajeev V. Pillai <rajeevvp@yahoo.com> | |
331 | */ | |
332 | static void | |
333 | parse_minix(struct parsed_partitions *state, struct block_device *bdev, | |
334 | u32 offset, u32 size, int origin) | |
335 | { | |
336 | #ifdef CONFIG_MINIX_SUBPARTITION | |
337 | Sector sect; | |
338 | unsigned char *data; | |
339 | struct partition *p; | |
340 | int i; | |
341 | ||
342 | data = read_dev_sector(bdev, offset, §); | |
343 | if (!data) | |
344 | return; | |
345 | ||
346 | p = (struct partition *)(data + 0x1be); | |
347 | ||
348 | /* The first sector of a Minix partition can have either | |
349 | * a secondary MBR describing its subpartitions, or | |
350 | * the normal boot sector. */ | |
351 | if (msdos_magic_present (data + 510) && | |
352 | SYS_IND(p) == MINIX_PARTITION) { /* subpartition table present */ | |
353 | ||
354 | printk(" %s%d: <minix:", state->name, origin); | |
355 | for (i = 0; i < MINIX_NR_SUBPARTITIONS; i++, p++) { | |
356 | if (state->next == state->limit) | |
357 | break; | |
358 | /* add each partition in use */ | |
359 | if (SYS_IND(p) == MINIX_PARTITION) | |
360 | put_partition(state, state->next++, | |
361 | START_SECT(p), NR_SECTS(p)); | |
362 | } | |
363 | printk(" >\n"); | |
364 | } | |
365 | put_dev_sector(sect); | |
366 | #endif /* CONFIG_MINIX_SUBPARTITION */ | |
367 | } | |
368 | ||
369 | static struct { | |
370 | unsigned char id; | |
371 | void (*parse)(struct parsed_partitions *, struct block_device *, | |
372 | u32, u32, int); | |
373 | } subtypes[] = { | |
374 | {FREEBSD_PARTITION, parse_freebsd}, | |
375 | {NETBSD_PARTITION, parse_netbsd}, | |
376 | {OPENBSD_PARTITION, parse_openbsd}, | |
377 | {MINIX_PARTITION, parse_minix}, | |
378 | {UNIXWARE_PARTITION, parse_unixware}, | |
379 | {SOLARIS_X86_PARTITION, parse_solaris_x86}, | |
380 | {NEW_SOLARIS_X86_PARTITION, parse_solaris_x86}, | |
381 | {0, NULL}, | |
382 | }; | |
383 | ||
384 | int msdos_partition(struct parsed_partitions *state, struct block_device *bdev) | |
385 | { | |
386 | int sector_size = bdev_hardsect_size(bdev) / 512; | |
387 | Sector sect; | |
388 | unsigned char *data; | |
389 | struct partition *p; | |
390 | int slot; | |
391 | ||
392 | data = read_dev_sector(bdev, 0, §); | |
393 | if (!data) | |
394 | return -1; | |
395 | if (!msdos_magic_present(data + 510)) { | |
396 | put_dev_sector(sect); | |
397 | return 0; | |
398 | } | |
399 | ||
400 | /* | |
401 | * Now that the 55aa signature is present, this is probably | |
402 | * either the boot sector of a FAT filesystem or a DOS-type | |
403 | * partition table. Reject this in case the boot indicator | |
404 | * is not 0 or 0x80. | |
405 | */ | |
406 | p = (struct partition *) (data + 0x1be); | |
407 | for (slot = 1; slot <= 4; slot++, p++) { | |
408 | if (p->boot_ind != 0 && p->boot_ind != 0x80) { | |
409 | put_dev_sector(sect); | |
410 | return 0; | |
411 | } | |
412 | } | |
413 | ||
414 | #ifdef CONFIG_EFI_PARTITION | |
415 | p = (struct partition *) (data + 0x1be); | |
416 | for (slot = 1 ; slot <= 4 ; slot++, p++) { | |
417 | /* If this is an EFI GPT disk, msdos should ignore it. */ | |
418 | if (SYS_IND(p) == EFI_PMBR_OSTYPE_EFI_GPT) { | |
419 | put_dev_sector(sect); | |
420 | return 0; | |
421 | } | |
422 | } | |
423 | #endif | |
424 | p = (struct partition *) (data + 0x1be); | |
425 | ||
426 | /* | |
427 | * Look for partitions in two passes: | |
428 | * First find the primary and DOS-type extended partitions. | |
429 | * On the second pass look inside *BSD, Unixware and Solaris partitions. | |
430 | */ | |
431 | ||
432 | state->next = 5; | |
433 | for (slot = 1 ; slot <= 4 ; slot++, p++) { | |
434 | u32 start = START_SECT(p)*sector_size; | |
435 | u32 size = NR_SECTS(p)*sector_size; | |
436 | if (SYS_IND(p) == 0) | |
437 | continue; | |
438 | if (!size) | |
439 | continue; | |
440 | if (is_extended_partition(p)) { | |
441 | /* prevent someone doing mkfs or mkswap on an | |
442 | extended partition, but leave room for LILO */ | |
443 | put_partition(state, slot, start, size == 1 ? 1 : 2); | |
444 | printk(" <"); | |
445 | parse_extended(state, bdev, start, size); | |
446 | printk(" >"); | |
447 | continue; | |
448 | } | |
449 | put_partition(state, slot, start, size); | |
450 | if (SYS_IND(p) == LINUX_RAID_PARTITION) | |
451 | state->parts[slot].flags = 1; | |
452 | if (SYS_IND(p) == DM6_PARTITION) | |
453 | printk("[DM]"); | |
454 | if (SYS_IND(p) == EZD_PARTITION) | |
455 | printk("[EZD]"); | |
456 | } | |
457 | ||
458 | printk("\n"); | |
459 | ||
460 | /* second pass - output for each on a separate line */ | |
461 | p = (struct partition *) (0x1be + data); | |
462 | for (slot = 1 ; slot <= 4 ; slot++, p++) { | |
463 | unsigned char id = SYS_IND(p); | |
464 | int n; | |
465 | ||
466 | if (!NR_SECTS(p)) | |
467 | continue; | |
468 | ||
469 | for (n = 0; subtypes[n].parse && id != subtypes[n].id; n++) | |
470 | ; | |
471 | ||
472 | if (!subtypes[n].parse) | |
473 | continue; | |
474 | subtypes[n].parse(state, bdev, START_SECT(p)*sector_size, | |
475 | NR_SECTS(p)*sector_size, slot); | |
476 | } | |
477 | put_dev_sector(sect); | |
478 | return 1; | |
479 | } |