Disallow writes to filesystems mounted read-only via NULLFS. In this case
[dragonfly.git] / sys / kern / subr_diskmbr.c
CommitLineData
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1/*-
2 * Copyright (c) 1994 Bruce D. Evans.
3 * All rights reserved.
4 *
5 * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: @(#)ufs_disksubr.c 7.16 (Berkeley) 5/4/91
37 * from: ufs_disksubr.c,v 1.8 1994/06/07 01:21:39 phk Exp $
38 * $FreeBSD: src/sys/kern/subr_diskmbr.c,v 1.45 2000/01/28 10:22:07 bde Exp $
b13267a5 39 * $DragonFly: src/sys/kern/subr_diskmbr.c,v 1.15 2006/09/10 01:26:39 dillon Exp $
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40 */
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/buf.h>
45#include <sys/conf.h>
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46#include <sys/disklabel.h>
47#define DOSPTYP_EXTENDED 5
48#define DOSPTYP_EXTENDEDX 15
49#define DOSPTYP_ONTRACK 84
50#include <sys/diskslice.h>
dc62b251 51#include <sys/diskmbr.h>
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52#include <sys/malloc.h>
53#include <sys/syslog.h>
335dda38 54#include <sys/device.h>
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55
56#define TRACE(str) do { if (dsi_debug) printf str; } while (0)
57
58static volatile u_char dsi_debug;
59
60static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
61 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
62 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
63 { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
64 { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
65};
66
402ed7e1 67static int check_part (char *sname, struct dos_partition *dp,
984263bc 68 u_long offset, int nsectors, int ntracks,
402ed7e1 69 u_long mbr_offset);
b13267a5 70static void mbr_extended (cdev_t dev, struct disklabel *lp,
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71 struct diskslices *ssp, u_long ext_offset,
72 u_long ext_size, u_long base_ext_offset,
73 int nsectors, int ntracks, u_long mbr_offset,
402ed7e1
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74 int level);
75static int mbr_setslice (char *sname, struct disklabel *lp,
984263bc 76 struct diskslice *sp, struct dos_partition *dp,
402ed7e1 77 u_long br_offset);
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78
79static int
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80check_part(char *sname, struct dos_partition *dp, u_long offset,
81 int nsectors, int ntracks, u_long mbr_offset)
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82{
83 int chs_ecyl;
84 int chs_esect;
85 int chs_scyl;
86 int chs_ssect;
87 int error;
88 u_long esector;
89 u_long esector1;
90 u_long secpercyl;
91 u_long ssector;
92 u_long ssector1;
93
94 secpercyl = (u_long)nsectors * ntracks;
95 chs_scyl = DPCYL(dp->dp_scyl, dp->dp_ssect);
96 chs_ssect = DPSECT(dp->dp_ssect);
97 ssector = chs_ssect - 1 + dp->dp_shd * nsectors + chs_scyl * secpercyl
98 + mbr_offset;
99 ssector1 = offset + dp->dp_start;
100
101 /*
102 * If ssector1 is on a cylinder >= 1024, then ssector can't be right.
103 * Allow the C/H/S for it to be 1023/ntracks-1/nsectors, or correct
104 * apart from the cylinder being reduced modulo 1024. Always allow
105 * 1023/255/63.
106 */
107 if ((ssector < ssector1
108 && ((chs_ssect == nsectors && dp->dp_shd == ntracks - 1
109 && chs_scyl == 1023)
110 || (secpercyl != 0
111 && (ssector1 - ssector) % (1024 * secpercyl) == 0)))
112 || (dp->dp_scyl == 255 && dp->dp_shd == 255
113 && dp->dp_ssect == 255)) {
114 TRACE(("%s: C/H/S start %d/%d/%d, start %lu: allow\n",
115 sname, chs_scyl, dp->dp_shd, chs_ssect, ssector1));
116 ssector = ssector1;
117 }
118
119 chs_ecyl = DPCYL(dp->dp_ecyl, dp->dp_esect);
120 chs_esect = DPSECT(dp->dp_esect);
121 esector = chs_esect - 1 + dp->dp_ehd * nsectors + chs_ecyl * secpercyl
122 + mbr_offset;
123 esector1 = ssector1 + dp->dp_size - 1;
124
125 /* Allow certain bogus C/H/S values for esector, as above. */
126 if ((esector < esector1
127 && ((chs_esect == nsectors && dp->dp_ehd == ntracks - 1
128 && chs_ecyl == 1023)
129 || (secpercyl != 0
130 && (esector1 - esector) % (1024 * secpercyl) == 0)))
131 || (dp->dp_ecyl == 255 && dp->dp_ehd == 255
132 && dp->dp_esect == 255)) {
133 TRACE(("%s: C/H/S end %d/%d/%d, end %lu: allow\n",
134 sname, chs_ecyl, dp->dp_ehd, chs_esect, esector1));
135 esector = esector1;
136 }
137
138 error = (ssector == ssector1 && esector == esector1) ? 0 : EINVAL;
139 if (bootverbose)
140 printf("%s: type 0x%x, start %lu, end = %lu, size %lu %s\n",
141 sname, dp->dp_typ, ssector1, esector1,
142 (u_long)dp->dp_size, error ? "" : ": OK");
143 if (ssector != ssector1 && bootverbose)
144 printf("%s: C/H/S start %d/%d/%d (%lu) != start %lu: invalid\n",
145 sname, chs_scyl, dp->dp_shd, chs_ssect,
146 ssector, ssector1);
147 if (esector != esector1 && bootverbose)
148 printf("%s: C/H/S end %d/%d/%d (%lu) != end %lu: invalid\n",
149 sname, chs_ecyl, dp->dp_ehd, chs_esect,
150 esector, esector1);
151 return (error);
152}
153
154int
b13267a5 155dsinit(cdev_t dev, struct disklabel *lp, struct diskslices **sspp)
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156{
157 struct buf *bp;
158 u_char *cp;
159 int dospart;
160 struct dos_partition *dp;
161 struct dos_partition *dp0;
162 struct dos_partition dpcopy[NDOSPART];
163 int error;
164 int max_ncyls;
165 int max_nsectors;
166 int max_ntracks;
167 u_long mbr_offset;
168 char partname[2];
169 u_long secpercyl;
170 char *sname;
171 struct diskslice *sp;
172 struct diskslices *ssp;
b13267a5 173 cdev_t wdev;
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174
175 mbr_offset = DOSBBSECTOR;
176reread_mbr:
177 /* Read master boot record. */
7843d540 178 wdev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
984263bc 179 bp = geteblk((int)lp->d_secsize);
54078292 180 bp->b_bio1.bio_offset = (off_t)mbr_offset * lp->d_secsize;
984263bc 181 bp->b_bcount = lp->d_secsize;
10f3fee5 182 bp->b_cmd = BUF_CMD_READ;
81b5c339 183 dev_dstrategy(wdev, &bp->b_bio1);
984263bc 184 if (biowait(bp) != 0) {
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185 diskerr(&bp->b_bio1, wdev,
186 "reading primary partition table: error",
54078292 187 LOG_PRINTF, 0, NULL);
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188 printf("\n");
189 error = EIO;
190 goto done;
191 }
192
193 /* Weakly verify it. */
194 cp = bp->b_data;
195 sname = dsname(dev, dkunit(dev), WHOLE_DISK_SLICE, RAW_PART, partname);
196 if (cp[0x1FE] != 0x55 || cp[0x1FF] != 0xAA) {
197 if (bootverbose)
198 printf("%s: invalid primary partition table: no magic\n",
199 sname);
200 error = EINVAL;
201 goto done;
202 }
203
204 /* Make a copy of the partition table to avoid alignment problems. */
205 memcpy(&dpcopy[0], cp + DOSPARTOFF, sizeof(dpcopy));
206
207 dp0 = &dpcopy[0];
208
209 /* Check for "Ontrack Diskmanager". */
210 for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++) {
211 if (dp->dp_typ == DOSPTYP_ONTRACK) {
212 if (bootverbose)
213 printf(
214 "%s: Found \"Ontrack Disk Manager\" on this disk.\n", sname);
215 bp->b_flags |= B_INVAL | B_AGE;
216 brelse(bp);
217 mbr_offset = 63;
218 goto reread_mbr;
219 }
220 }
221
222 if (bcmp(dp0, historical_bogus_partition_table,
223 sizeof historical_bogus_partition_table) == 0) {
224 TRACE(("%s: invalid primary partition table: historical\n",
225 sname));
226 error = EINVAL;
227 goto done;
228 }
229
230 /* Guess the geometry. */
231 /*
232 * TODO:
233 * Perhaps skip entries with 0 size.
234 * Perhaps only look at entries of type DOSPTYP_386BSD.
235 */
236 max_ncyls = 0;
237 max_nsectors = 0;
238 max_ntracks = 0;
239 for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++) {
240 int ncyls;
241 int nsectors;
242 int ntracks;
243
244 ncyls = DPCYL(dp->dp_ecyl, dp->dp_esect) + 1;
245 if (max_ncyls < ncyls)
246 max_ncyls = ncyls;
247 nsectors = DPSECT(dp->dp_esect);
248 if (max_nsectors < nsectors)
249 max_nsectors = nsectors;
250 ntracks = dp->dp_ehd + 1;
251 if (max_ntracks < ntracks)
252 max_ntracks = ntracks;
253 }
254
255 /*
256 * Check that we have guessed the geometry right by checking the
257 * partition entries.
258 */
259 /*
260 * TODO:
261 * As above.
262 * Check for overlaps.
263 * Check against d_secperunit if the latter is reliable.
264 */
265 error = 0;
266 for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++) {
267 if (dp->dp_scyl == 0 && dp->dp_shd == 0 && dp->dp_ssect == 0
268 && dp->dp_start == 0 && dp->dp_size == 0)
269 continue;
270 sname = dsname(dev, dkunit(dev), BASE_SLICE + dospart,
271 RAW_PART, partname);
272
273 /*
274 * Temporarily ignore errors from this check. We could
275 * simplify things by accepting the table eariler if we
276 * always ignore errors here. Perhaps we should always
277 * accept the table if the magic is right but not let
278 * bad entries affect the geometry.
279 */
280 check_part(sname, dp, mbr_offset, max_nsectors, max_ntracks,
281 mbr_offset);
282 }
283 if (error != 0)
284 goto done;
285
286 /*
287 * Accept the DOS partition table.
288 * First adjust the label (we have been careful not to change it
289 * before we can guarantee success).
290 */
291 secpercyl = (u_long)max_nsectors * max_ntracks;
292 if (secpercyl != 0) {
293#if 0
294 u_long secperunit;
295#endif
296
297 lp->d_nsectors = max_nsectors;
298 lp->d_ntracks = max_ntracks;
299 lp->d_secpercyl = secpercyl;
300 /*
301 * Temporarily, don't even consider adjusting the drive's
302 * size, since the adjusted size may exceed the hardware's
303 * addressing capabilities. The adjustment helped mainly
304 * for ancient MFM drives with > 1024 cylinders, but now
305 * breaks at least IDE drives with 63*16*65536 sectors if
306 * they are controlled by the wd driver in CHS mode.
307 */
308#if 0
309 secperunit = secpercyl * max_ncyls;
310 if (lp->d_secperunit < secperunit)
311 lp->d_secperunit = secperunit;
312#endif
313 lp->d_ncylinders = lp->d_secperunit / secpercyl;
314 }
315
316 /*
317 * We are passed a pointer to a suitably initialized minimal
318 * slices "struct" with no dangling pointers in it. Replace it
319 * by a maximal one. This usually oversizes the "struct", but
320 * enlarging it while searching for logical drives would be
321 * inconvenient.
322 */
efda3bd0 323 kfree(*sspp, M_DEVBUF);
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324 ssp = dsmakeslicestruct(MAX_SLICES, lp);
325 *sspp = ssp;
326
327 /* Initialize normal slices. */
328 sp = &ssp->dss_slices[BASE_SLICE];
329 for (dospart = 0, dp = dp0; dospart < NDOSPART; dospart++, dp++, sp++) {
330 sname = dsname(dev, dkunit(dev), BASE_SLICE + dospart,
331 RAW_PART, partname);
332 (void)mbr_setslice(sname, lp, sp, dp, mbr_offset);
333 }
334 ssp->dss_nslices = BASE_SLICE + NDOSPART;
335
336 /* Handle extended partitions. */
337 sp -= NDOSPART;
a0c19955 338 for (dospart = 0; dospart < NDOSPART; dospart++, sp++) {
984263bc 339 if (sp->ds_type == DOSPTYP_EXTENDED ||
a0c19955 340 sp->ds_type == DOSPTYP_EXTENDEDX) {
7843d540 341 mbr_extended(wdev, lp, ssp,
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342 sp->ds_offset, sp->ds_size, sp->ds_offset,
343 max_nsectors, max_ntracks, mbr_offset, 1);
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344 }
345 }
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346
347 /*
348 * mbr_extended() abuses ssp->dss_nslices for the number of slices
349 * that would be found if there were no limit on the number of slices
350 * in *ssp. Cut it back now.
351 */
352 if (ssp->dss_nslices > MAX_SLICES)
353 ssp->dss_nslices = MAX_SLICES;
354
355done:
356 bp->b_flags |= B_INVAL | B_AGE;
357 brelse(bp);
358 if (error == EINVAL)
359 error = 0;
360 return (error);
361}
362
363void
b13267a5 364mbr_extended(cdev_t dev, struct disklabel *lp, struct diskslices *ssp,
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365 u_long ext_offset, u_long ext_size, u_long base_ext_offset,
366 int nsectors, int ntracks, u_long mbr_offset, int level)
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367{
368 struct buf *bp;
369 u_char *cp;
370 int dospart;
371 struct dos_partition *dp;
372 struct dos_partition dpcopy[NDOSPART];
373 u_long ext_offsets[NDOSPART];
374 u_long ext_sizes[NDOSPART];
375 char partname[2];
376 int slice;
377 char *sname;
378 struct diskslice *sp;
379
380 if (level >= 16) {
381 printf(
382 "%s: excessive recursion in search for slices; aborting search\n",
383 devtoname(dev));
384 return;
385 }
386
387 /* Read extended boot record. */
388 bp = geteblk((int)lp->d_secsize);
54078292 389 bp->b_bio1.bio_offset = (off_t)ext_offset * lp->d_secsize;
984263bc 390 bp->b_bcount = lp->d_secsize;
10f3fee5 391 bp->b_cmd = BUF_CMD_READ;
81b5c339 392 dev_dstrategy(dev, &bp->b_bio1);
984263bc 393 if (biowait(bp) != 0) {
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394 diskerr(&bp->b_bio1, dev,
395 "reading extended partition table: error",
54078292 396 LOG_PRINTF, 0, NULL);
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397 printf("\n");
398 goto done;
399 }
400
401 /* Weakly verify it. */
402 cp = bp->b_data;
403 if (cp[0x1FE] != 0x55 || cp[0x1FF] != 0xAA) {
404 sname = dsname(dev, dkunit(dev), WHOLE_DISK_SLICE, RAW_PART,
405 partname);
406 if (bootverbose)
407 printf("%s: invalid extended partition table: no magic\n",
408 sname);
409 goto done;
410 }
411
412 /* Make a copy of the partition table to avoid alignment problems. */
413 memcpy(&dpcopy[0], cp + DOSPARTOFF, sizeof(dpcopy));
414
415 slice = ssp->dss_nslices;
416 for (dospart = 0, dp = &dpcopy[0]; dospart < NDOSPART;
417 dospart++, dp++) {
418 ext_sizes[dospart] = 0;
419 if (dp->dp_scyl == 0 && dp->dp_shd == 0 && dp->dp_ssect == 0
420 && dp->dp_start == 0 && dp->dp_size == 0)
421 continue;
422 if (dp->dp_typ == DOSPTYP_EXTENDED ||
423 dp->dp_typ == DOSPTYP_EXTENDEDX) {
424 static char buf[32];
425
426 sname = dsname(dev, dkunit(dev), WHOLE_DISK_SLICE,
427 RAW_PART, partname);
428 snprintf(buf, sizeof(buf), "%s", sname);
429 if (strlen(buf) < sizeof buf - 11)
430 strcat(buf, "<extended>");
431 check_part(buf, dp, base_ext_offset, nsectors,
432 ntracks, mbr_offset);
433 ext_offsets[dospart] = base_ext_offset + dp->dp_start;
434 ext_sizes[dospart] = dp->dp_size;
435 } else {
436 sname = dsname(dev, dkunit(dev), slice, RAW_PART,
437 partname);
438 check_part(sname, dp, ext_offset, nsectors, ntracks,
439 mbr_offset);
440 if (slice >= MAX_SLICES) {
441 printf("%s: too many slices\n", sname);
442 slice++;
443 continue;
444 }
445 sp = &ssp->dss_slices[slice];
446 if (mbr_setslice(sname, lp, sp, dp, ext_offset) != 0)
447 continue;
448 slice++;
449 }
450 }
451 ssp->dss_nslices = slice;
452
453 /* If we found any more slices, recursively find all the subslices. */
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454 for (dospart = 0; dospart < NDOSPART; dospart++) {
455 if (ext_sizes[dospart] != 0) {
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456 mbr_extended(dev, lp, ssp, ext_offsets[dospart],
457 ext_sizes[dospart], base_ext_offset,
458 nsectors, ntracks, mbr_offset, ++level);
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459 }
460 }
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461
462done:
463 bp->b_flags |= B_INVAL | B_AGE;
464 brelse(bp);
465}
466
467static int
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468mbr_setslice(char *sname, struct disklabel *lp, struct diskslice *sp,
469 struct dos_partition *dp, u_long br_offset)
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470{
471 u_long offset;
472 u_long size;
473
474 offset = br_offset + dp->dp_start;
475 if (offset > lp->d_secperunit || offset < br_offset) {
476 printf(
477 "%s: slice starts beyond end of the disk: rejecting it\n",
478 sname);
479 return (1);
480 }
481 size = lp->d_secperunit - offset;
482 if (size >= dp->dp_size)
483 size = dp->dp_size;
484 else
485 printf(
486"%s: slice extends beyond end of disk: truncating from %lu to %lu sectors\n",
487 sname, (u_long)dp->dp_size, size);
488 sp->ds_offset = offset;
489 sp->ds_size = size;
490 sp->ds_type = dp->dp_typ;
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491#if 0
492 lp->d_subtype |= (lp->d_subtype & 3) | dospart | DSTYPE_INDOSPART;
493#endif
494 return (0);
495}