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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/partitions/msdos.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/partitions/msdos.c')
-rw-r--r--fs/partitions/msdos.c479
1 files changed, 479 insertions, 0 deletions
diff --git a/fs/partitions/msdos.c b/fs/partitions/msdos.c
new file mode 100644
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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
46static 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
56static inline int
57msdos_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
73static void
74parse_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, &sect);
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 }
162done:
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
169static void
170parse_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, &sect);
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 */
213void
214parse_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, &sect);
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
259static void
260parse_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
269static void
270parse_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
279static void
280parse_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 */
293static void
294parse_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, &sect);
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 */
332static void
333parse_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, &sect);
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
369static 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
384int 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, &sect);
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}