FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_bsd.c
1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2002 Poul-Henning Kamp
5 * Copyright (c) 2002 Networks Associates Technology, Inc.
6 * All rights reserved.
7 *
8 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
9 * and NAI Labs, the Security Research Division of Network Associates, Inc.
10 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
11 * DARPA CHATS research program.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. The names of the authors may not be used to endorse or promote
22 * products derived from this software without specific prior written
23 * permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 */
37
38 /*
39 * This is the method for dealing with BSD disklabels. It has been
40 * extensively (by my standards at least) commented, in the vain hope that
41 * it will serve as the source in future copy&paste operations.
42 */
43
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46
47 #include <sys/param.h>
48 #include <sys/endian.h>
49 #include <sys/systm.h>
50 #include <sys/sysctl.h>
51 #include <sys/kernel.h>
52 #include <sys/fcntl.h>
53 #include <sys/conf.h>
54 #include <sys/bio.h>
55 #include <sys/malloc.h>
56 #include <sys/lock.h>
57 #include <sys/mutex.h>
58 #include <sys/md5.h>
59 #include <sys/errno.h>
60 #include <sys/disklabel.h>
61 #include <sys/gpt.h>
62 #include <sys/proc.h>
63 #include <sys/sbuf.h>
64 #include <sys/uuid.h>
65 #include <geom/geom.h>
66 #include <geom/geom_slice.h>
67
68 FEATURE(geom_bsd, "GEOM BSD disklabels support");
69
70 #define BSD_CLASS_NAME "BSD"
71
72 #define ALPHA_LABEL_OFFSET 64
73 #define HISTORIC_LABEL_OFFSET 512
74
75 #define LABELSIZE (148 + 16 * MAXPARTITIONS)
76
77 static int g_bsd_once;
78
79 static void g_bsd_hotwrite(void *arg, int flag);
80 /*
81 * Our private data about one instance. All the rest is handled by the
82 * slice code and stored in its softc, so this is just the stuff
83 * specific to BSD disklabels.
84 */
85 struct g_bsd_softc {
86 off_t labeloffset;
87 off_t mbroffset;
88 off_t rawoffset;
89 struct disklabel ondisk;
90 u_char label[LABELSIZE];
91 u_char labelsum[16];
92 };
93
94 /*
95 * Modify our slicer to match proposed disklabel, if possible.
96 * This is where we make sure we don't do something stupid.
97 */
98 static int
99 g_bsd_modify(struct g_geom *gp, u_char *label)
100 {
101 int i, error;
102 struct partition *ppp;
103 struct g_slicer *gsp;
104 struct g_consumer *cp;
105 struct g_bsd_softc *ms;
106 u_int secsize, u;
107 off_t rawoffset, o;
108 struct disklabel dl;
109 MD5_CTX md5sum;
110
111 g_topology_assert();
112 gsp = gp->softc;
113 ms = gsp->softc;
114
115 error = bsd_disklabel_le_dec(label, &dl, MAXPARTITIONS);
116 if (error) {
117 return (error);
118 }
119
120 /* Get dimensions of our device. */
121 cp = LIST_FIRST(&gp->consumer);
122 secsize = cp->provider->sectorsize;
123
124 /* ... or a smaller sector size. */
125 if (dl.d_secsize < secsize) {
126 return (EINVAL);
127 }
128
129 /* ... or a non-multiple sector size. */
130 if (dl.d_secsize % secsize != 0) {
131 return (EINVAL);
132 }
133
134 /* Historical braindamage... */
135 rawoffset = (off_t)dl.d_partitions[RAW_PART].p_offset * dl.d_secsize;
136
137 for (i = 0; i < dl.d_npartitions; i++) {
138 ppp = &dl.d_partitions[i];
139 if (ppp->p_size == 0)
140 continue;
141 o = (off_t)ppp->p_offset * dl.d_secsize;
142
143 if (o < rawoffset)
144 rawoffset = 0;
145 }
146
147 if (rawoffset != 0 && (off_t)rawoffset != ms->mbroffset)
148 printf("WARNING: %s expected rawoffset %jd, found %jd\n",
149 gp->name,
150 (intmax_t)ms->mbroffset/dl.d_secsize,
151 (intmax_t)rawoffset/dl.d_secsize);
152
153 /* Don't munge open partitions. */
154 for (i = 0; i < dl.d_npartitions; i++) {
155 ppp = &dl.d_partitions[i];
156
157 o = (off_t)ppp->p_offset * dl.d_secsize;
158 if (o == 0)
159 o = rawoffset;
160 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
161 o - rawoffset,
162 (off_t)ppp->p_size * dl.d_secsize,
163 dl.d_secsize,
164 "%s%c", gp->name, 'a' + i);
165 if (error)
166 return (error);
167 }
168
169 /* Look good, go for it... */
170 for (u = 0; u < gsp->nslice; u++) {
171 ppp = &dl.d_partitions[u];
172 o = (off_t)ppp->p_offset * dl.d_secsize;
173 if (o == 0)
174 o = rawoffset;
175 g_slice_config(gp, u, G_SLICE_CONFIG_SET,
176 o - rawoffset,
177 (off_t)ppp->p_size * dl.d_secsize,
178 dl.d_secsize,
179 "%s%c", gp->name, 'a' + u);
180 }
181
182 /* Update our softc */
183 ms->ondisk = dl;
184 if (label != ms->label)
185 bcopy(label, ms->label, LABELSIZE);
186 ms->rawoffset = rawoffset;
187
188 /*
189 * In order to avoid recursively attaching to the same
190 * on-disk label (it's usually visible through the 'c'
191 * partition) we calculate an MD5 and ask if other BSD's
192 * below us love that label. If they do, we don't.
193 */
194 MD5Init(&md5sum);
195 MD5Update(&md5sum, ms->label, sizeof(ms->label));
196 MD5Final(ms->labelsum, &md5sum);
197
198 return (0);
199 }
200
201 /*
202 * This is an internal helper function, called multiple times from the taste
203 * function to try to locate a disklabel on the disk. More civilized formats
204 * will not need this, as there is only one possible place on disk to look
205 * for the magic spot.
206 */
207
208 static int
209 g_bsd_try(struct g_geom *gp, struct g_slicer *gsp, struct g_consumer *cp, int secsize, struct g_bsd_softc *ms, off_t offset)
210 {
211 int error;
212 u_char *buf;
213 struct disklabel *dl;
214 off_t secoff;
215
216 /*
217 * We need to read entire aligned sectors, and we assume that the
218 * disklabel does not span sectors, so one sector is enough.
219 */
220 secoff = offset % secsize;
221 buf = g_read_data(cp, offset - secoff, secsize, NULL);
222 if (buf == NULL)
223 return (ENOENT);
224
225 /* Decode into our native format. */
226 dl = &ms->ondisk;
227 error = bsd_disklabel_le_dec(buf + secoff, dl, MAXPARTITIONS);
228 if (!error)
229 bcopy(buf + secoff, ms->label, LABELSIZE);
230
231 /* Remember to free the buffer g_read_data() gave us. */
232 g_free(buf);
233
234 ms->labeloffset = offset;
235 return (error);
236 }
237
238 /*
239 * This function writes the current label to disk, possibly updating
240 * the alpha SRM checksum.
241 */
242
243 static int
244 g_bsd_writelabel(struct g_geom *gp, u_char *bootcode)
245 {
246 off_t secoff;
247 u_int secsize;
248 struct g_consumer *cp;
249 struct g_slicer *gsp;
250 struct g_bsd_softc *ms;
251 u_char *buf;
252 uint64_t sum;
253 int error, i;
254
255 gsp = gp->softc;
256 ms = gsp->softc;
257 cp = LIST_FIRST(&gp->consumer);
258 /* Get sector size, we need it to read data. */
259 secsize = cp->provider->sectorsize;
260 secoff = ms->labeloffset % secsize;
261 if (bootcode == NULL) {
262 buf = g_read_data(cp, ms->labeloffset - secoff, secsize, &error);
263 if (buf == NULL)
264 return (error);
265 bcopy(ms->label, buf + secoff, sizeof(ms->label));
266 } else {
267 buf = bootcode;
268 bcopy(ms->label, buf + ms->labeloffset, sizeof(ms->label));
269 }
270 if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
271 sum = 0;
272 for (i = 0; i < 63; i++)
273 sum += le64dec(buf + i * 8);
274 le64enc(buf + 504, sum);
275 }
276 if (bootcode == NULL) {
277 error = g_write_data(cp, ms->labeloffset - secoff, buf, secsize);
278 g_free(buf);
279 } else {
280 error = g_write_data(cp, 0, bootcode, BBSIZE);
281 }
282 return(error);
283 }
284
285 /*
286 * If the user tries to overwrite our disklabel through an open partition
287 * or via a magicwrite config call, we end up here and try to prevent
288 * footshooting as best we can.
289 */
290 static void
291 g_bsd_hotwrite(void *arg, int flag)
292 {
293 struct bio *bp;
294 struct g_geom *gp;
295 struct g_slicer *gsp;
296 struct g_slice *gsl;
297 struct g_bsd_softc *ms;
298 u_char *p;
299 int error;
300
301 g_topology_assert();
302 /*
303 * We should never get canceled, because that would amount to a removal
304 * of the geom while there was outstanding I/O requests.
305 */
306 KASSERT(flag != EV_CANCEL, ("g_bsd_hotwrite cancelled"));
307 bp = arg;
308 gp = bp->bio_to->geom;
309 gsp = gp->softc;
310 ms = gsp->softc;
311 gsl = &gsp->slices[bp->bio_to->index];
312 p = (u_char*)bp->bio_data + ms->labeloffset -
313 (bp->bio_offset + gsl->offset);
314 error = g_bsd_modify(gp, p);
315 if (error) {
316 g_io_deliver(bp, EPERM);
317 return;
318 }
319 g_slice_finish_hot(bp);
320 }
321
322 static int
323 g_bsd_start(struct bio *bp)
324 {
325 struct g_geom *gp;
326 struct g_bsd_softc *ms;
327 struct g_slicer *gsp;
328
329 gp = bp->bio_to->geom;
330 gsp = gp->softc;
331 ms = gsp->softc;
332 if (bp->bio_cmd == BIO_GETATTR) {
333 if (g_handleattr(bp, "BSD::labelsum", ms->labelsum,
334 sizeof(ms->labelsum)))
335 return (1);
336 }
337 return (0);
338 }
339
340 /*
341 * Dump configuration information in XML format.
342 * Notice that the function is called once for the geom and once for each
343 * consumer and provider. We let g_slice_dumpconf() do most of the work.
344 */
345 static void
346 g_bsd_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
347 {
348 struct g_bsd_softc *ms;
349 struct g_slicer *gsp;
350
351 gsp = gp->softc;
352 ms = gsp->softc;
353 g_slice_dumpconf(sb, indent, gp, cp, pp);
354 if (indent != NULL && pp == NULL && cp == NULL) {
355 sbuf_printf(sb, "%s<labeloffset>%jd</labeloffset>\n",
356 indent, (intmax_t)ms->labeloffset);
357 sbuf_printf(sb, "%s<rawoffset>%jd</rawoffset>\n",
358 indent, (intmax_t)ms->rawoffset);
359 sbuf_printf(sb, "%s<mbroffset>%jd</mbroffset>\n",
360 indent, (intmax_t)ms->mbroffset);
361 } else if (pp != NULL) {
362 if (indent == NULL)
363 sbuf_printf(sb, " ty %d",
364 ms->ondisk.d_partitions[pp->index].p_fstype);
365 else
366 sbuf_printf(sb, "%s<type>%d</type>\n", indent,
367 ms->ondisk.d_partitions[pp->index].p_fstype);
368 }
369 }
370
371 /*
372 * The taste function is called from the event-handler, with the topology
373 * lock already held and a provider to examine. The flags are unused.
374 *
375 * If flags == G_TF_NORMAL, the idea is to take a bite of the provider and
376 * if we find valid, consistent magic on it, build a geom on it.
377 *
378 * There may be cases where the operator would like to put a BSD-geom on
379 * providers which do not meet all of the requirements. This can be done
380 * by instead passing the G_TF_INSIST flag, which will override these
381 * checks.
382 *
383 * The final flags value is G_TF_TRANSPARENT, which instructs the method
384 * to put a geom on top of the provider and configure it to be as transparent
385 * as possible. This is not really relevant to the BSD method and therefore
386 * not implemented here.
387 */
388
389 static struct uuid freebsd_slice = GPT_ENT_TYPE_FREEBSD;
390
391 static struct g_geom *
392 g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
393 {
394 struct g_geom *gp;
395 struct g_consumer *cp;
396 int error, i;
397 struct g_bsd_softc *ms;
398 u_int secsize;
399 struct g_slicer *gsp;
400 u_char hash[16];
401 MD5_CTX md5sum;
402 struct uuid uuid;
403
404 g_trace(G_T_TOPOLOGY, "bsd_taste(%s,%s)", mp->name, pp->name);
405 g_topology_assert();
406
407 /* We don't implement transparent inserts. */
408 if (flags == G_TF_TRANSPARENT)
409 return (NULL);
410
411 /*
412 * BSD labels are a subclass of the general "slicing" topology so
413 * a lot of the work can be done by the common "slice" code.
414 * Create a geom with space for MAXPARTITIONS providers, one consumer
415 * and a softc structure for us. Specify the provider to attach
416 * the consumer to and our "start" routine for special requests.
417 * The provider is opened with mode (1,0,0) so we can do reads
418 * from it.
419 */
420 gp = g_slice_new(mp, MAXPARTITIONS, pp, &cp, &ms,
421 sizeof(*ms), g_bsd_start);
422 if (gp == NULL)
423 return (NULL);
424
425 /* Get the geom_slicer softc from the geom. */
426 gsp = gp->softc;
427
428 /*
429 * The do...while loop here allows us to have multiple escapes
430 * using a simple "break". This improves code clarity without
431 * ending up in deep nesting and without using goto or come from.
432 */
433 do {
434 /*
435 * If the provider is an MBR we will only auto attach
436 * to type 165 slices in the G_TF_NORMAL case. We will
437 * attach to any other type.
438 */
439 error = g_getattr("MBR::type", cp, &i);
440 if (!error) {
441 if (i != 165 && flags == G_TF_NORMAL)
442 break;
443 error = g_getattr("MBR::offset", cp, &ms->mbroffset);
444 if (error)
445 break;
446 }
447
448 /* Same thing if we are inside a GPT */
449 error = g_getattr("GPT::type", cp, &uuid);
450 if (!error) {
451 if (memcmp(&uuid, &freebsd_slice, sizeof(uuid)) != 0 &&
452 flags == G_TF_NORMAL)
453 break;
454 }
455
456 /* Get sector size, we need it to read data. */
457 secsize = cp->provider->sectorsize;
458 if (secsize < 512)
459 break;
460
461 /* First look for a label at the start of the second sector. */
462 error = g_bsd_try(gp, gsp, cp, secsize, ms, secsize);
463
464 /*
465 * If sector size is not 512 the label still can be at
466 * offset 512, not at the start of the second sector. At least
467 * it's true for labels created by the FreeBSD's bsdlabel(8).
468 */
469 if (error && secsize != HISTORIC_LABEL_OFFSET)
470 error = g_bsd_try(gp, gsp, cp, secsize, ms,
471 HISTORIC_LABEL_OFFSET);
472
473 /* Next, look for alpha labels */
474 if (error)
475 error = g_bsd_try(gp, gsp, cp, secsize, ms,
476 ALPHA_LABEL_OFFSET);
477
478 /* If we didn't find a label, punt. */
479 if (error)
480 break;
481
482 /*
483 * In order to avoid recursively attaching to the same
484 * on-disk label (it's usually visible through the 'c'
485 * partition) we calculate an MD5 and ask if other BSD's
486 * below us love that label. If they do, we don't.
487 */
488 MD5Init(&md5sum);
489 MD5Update(&md5sum, ms->label, sizeof(ms->label));
490 MD5Final(ms->labelsum, &md5sum);
491
492 error = g_getattr("BSD::labelsum", cp, &hash);
493 if (!error && !bcmp(ms->labelsum, hash, sizeof(hash)))
494 break;
495
496 /*
497 * Process the found disklabel, and modify our "slice"
498 * instance to match it, if possible.
499 */
500 error = g_bsd_modify(gp, ms->label);
501 } while (0);
502
503 /* Success or failure, we can close our provider now. */
504 g_access(cp, -1, 0, 0);
505
506 /* If we have configured any providers, return the new geom. */
507 if (gsp->nprovider > 0) {
508 g_slice_conf_hot(gp, 0, ms->labeloffset, LABELSIZE,
509 G_SLICE_HOT_ALLOW, G_SLICE_HOT_DENY, G_SLICE_HOT_CALL);
510 gsp->hot = g_bsd_hotwrite;
511 if (!g_bsd_once) {
512 g_bsd_once = 1;
513 printf(
514 "WARNING: geom_bsd (geom %s) is deprecated, "
515 "use gpart instead.\n", gp->name);
516 }
517 return (gp);
518 }
519 /*
520 * ...else push the "self-destruct" button, by spoiling our own
521 * consumer. This triggers a call to g_slice_spoiled which will
522 * dismantle what was setup.
523 */
524 g_slice_spoiled(cp);
525 return (NULL);
526 }
527
528 struct h0h0 {
529 struct g_geom *gp;
530 struct g_bsd_softc *ms;
531 u_char *label;
532 int error;
533 };
534
535 static void
536 g_bsd_callconfig(void *arg, int flag)
537 {
538 struct h0h0 *hp;
539
540 hp = arg;
541 hp->error = g_bsd_modify(hp->gp, hp->label);
542 if (!hp->error)
543 hp->error = g_bsd_writelabel(hp->gp, NULL);
544 }
545
546 /*
547 * NB! curthread is user process which GCTL'ed.
548 */
549 static void
550 g_bsd_config(struct gctl_req *req, struct g_class *mp, char const *verb)
551 {
552 u_char *label;
553 int error;
554 struct h0h0 h0h0;
555 struct g_geom *gp;
556 struct g_slicer *gsp;
557 struct g_consumer *cp;
558 struct g_bsd_softc *ms;
559
560 g_topology_assert();
561 gp = gctl_get_geom(req, mp, "geom");
562 if (gp == NULL)
563 return;
564 cp = LIST_FIRST(&gp->consumer);
565 gsp = gp->softc;
566 ms = gsp->softc;
567 if (!strcmp(verb, "read mbroffset")) {
568 gctl_set_param_err(req, "mbroffset", &ms->mbroffset,
569 sizeof(ms->mbroffset));
570 return;
571 } else if (!strcmp(verb, "write label")) {
572 label = gctl_get_paraml(req, "label", LABELSIZE);
573 if (label == NULL)
574 return;
575 h0h0.gp = gp;
576 h0h0.ms = gsp->softc;
577 h0h0.label = label;
578 h0h0.error = -1;
579 /* XXX: Does this reference register with our selfdestruct code ? */
580 error = g_access(cp, 1, 1, 1);
581 if (error) {
582 gctl_error(req, "could not access consumer");
583 return;
584 }
585 g_bsd_callconfig(&h0h0, 0);
586 error = h0h0.error;
587 g_access(cp, -1, -1, -1);
588 } else if (!strcmp(verb, "write bootcode")) {
589 label = gctl_get_paraml(req, "bootcode", BBSIZE);
590 if (label == NULL)
591 return;
592 /* XXX: Does this reference register with our selfdestruct code ? */
593 error = g_access(cp, 1, 1, 1);
594 if (error) {
595 gctl_error(req, "could not access consumer");
596 return;
597 }
598 error = g_bsd_writelabel(gp, label);
599 g_access(cp, -1, -1, -1);
600 } else {
601 gctl_error(req, "Unknown verb parameter");
602 }
603
604 return;
605 }
606
607 /* Finally, register with GEOM infrastructure. */
608 static struct g_class g_bsd_class = {
609 .name = BSD_CLASS_NAME,
610 .version = G_VERSION,
611 .taste = g_bsd_taste,
612 .ctlreq = g_bsd_config,
613 .dumpconf = g_bsd_dumpconf,
614 };
615
616 DECLARE_GEOM_CLASS(g_bsd_class, g_bsd);
617 MODULE_VERSION(geom_bsd, 0);
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