xref: /freebsd/sys/geom/part/g_part_ebr.c (revision 6ae1554a5d9b318f8ad53ccc39fa5a961403da73)
1 /*-
2  * Copyright (c) 2007-2009 Marcel Moolenaar
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include "opt_geom.h"
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/bio.h>
34 #include <sys/diskmbr.h>
35 #include <sys/endian.h>
36 #include <sys/kernel.h>
37 #include <sys/kobj.h>
38 #include <sys/limits.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/queue.h>
43 #include <sys/sbuf.h>
44 #include <sys/systm.h>
45 #include <sys/sysctl.h>
46 #include <geom/geom.h>
47 #include <geom/part/g_part.h>
48 
49 #include "g_part_if.h"
50 
51 FEATURE(geom_part_ebr,
52     "GEOM partitioning class for extended boot records support");
53 #if defined(GEOM_PART_EBR_COMPAT)
54 FEATURE(geom_part_ebr_compat,
55     "GEOM EBR partitioning class: backward-compatible partition names");
56 #endif
57 
58 #define	EBRSIZE		512
59 
60 struct g_part_ebr_table {
61 	struct g_part_table	base;
62 #ifndef GEOM_PART_EBR_COMPAT
63 	u_char		ebr[EBRSIZE];
64 #endif
65 };
66 
67 struct g_part_ebr_entry {
68 	struct g_part_entry	base;
69 	struct dos_partition	ent;
70 };
71 
72 static int g_part_ebr_add(struct g_part_table *, struct g_part_entry *,
73     struct g_part_parms *);
74 static int g_part_ebr_create(struct g_part_table *, struct g_part_parms *);
75 static int g_part_ebr_destroy(struct g_part_table *, struct g_part_parms *);
76 static void g_part_ebr_dumpconf(struct g_part_table *, struct g_part_entry *,
77     struct sbuf *, const char *);
78 static int g_part_ebr_dumpto(struct g_part_table *, struct g_part_entry *);
79 #if defined(GEOM_PART_EBR_COMPAT)
80 static void g_part_ebr_fullname(struct g_part_table *, struct g_part_entry *,
81     struct sbuf *, const char *);
82 #endif
83 static int g_part_ebr_modify(struct g_part_table *, struct g_part_entry *,
84     struct g_part_parms *);
85 static const char *g_part_ebr_name(struct g_part_table *, struct g_part_entry *,
86     char *, size_t);
87 static int g_part_ebr_precheck(struct g_part_table *, enum g_part_ctl,
88     struct g_part_parms *);
89 static int g_part_ebr_probe(struct g_part_table *, struct g_consumer *);
90 static int g_part_ebr_read(struct g_part_table *, struct g_consumer *);
91 static int g_part_ebr_setunset(struct g_part_table *, struct g_part_entry *,
92     const char *, unsigned int);
93 static const char *g_part_ebr_type(struct g_part_table *, struct g_part_entry *,
94     char *, size_t);
95 static int g_part_ebr_write(struct g_part_table *, struct g_consumer *);
96 static int g_part_ebr_resize(struct g_part_table *, struct g_part_entry *,
97     struct g_part_parms *);
98 
99 static kobj_method_t g_part_ebr_methods[] = {
100 	KOBJMETHOD(g_part_add,		g_part_ebr_add),
101 	KOBJMETHOD(g_part_create,	g_part_ebr_create),
102 	KOBJMETHOD(g_part_destroy,	g_part_ebr_destroy),
103 	KOBJMETHOD(g_part_dumpconf,	g_part_ebr_dumpconf),
104 	KOBJMETHOD(g_part_dumpto,	g_part_ebr_dumpto),
105 #if defined(GEOM_PART_EBR_COMPAT)
106 	KOBJMETHOD(g_part_fullname,	g_part_ebr_fullname),
107 #endif
108 	KOBJMETHOD(g_part_modify,	g_part_ebr_modify),
109 	KOBJMETHOD(g_part_name,		g_part_ebr_name),
110 	KOBJMETHOD(g_part_precheck,	g_part_ebr_precheck),
111 	KOBJMETHOD(g_part_probe,	g_part_ebr_probe),
112 	KOBJMETHOD(g_part_read,		g_part_ebr_read),
113 	KOBJMETHOD(g_part_resize,	g_part_ebr_resize),
114 	KOBJMETHOD(g_part_setunset,	g_part_ebr_setunset),
115 	KOBJMETHOD(g_part_type,		g_part_ebr_type),
116 	KOBJMETHOD(g_part_write,	g_part_ebr_write),
117 	{ 0, 0 }
118 };
119 
120 static struct g_part_scheme g_part_ebr_scheme = {
121 	"EBR",
122 	g_part_ebr_methods,
123 	sizeof(struct g_part_ebr_table),
124 	.gps_entrysz = sizeof(struct g_part_ebr_entry),
125 	.gps_minent = 1,
126 	.gps_maxent = INT_MAX,
127 };
128 G_PART_SCHEME_DECLARE(g_part_ebr);
129 
130 static struct g_part_ebr_alias {
131 	u_char		typ;
132 	int		alias;
133 } ebr_alias_match[] = {
134 	{ DOSPTYP_386BSD,	G_PART_ALIAS_FREEBSD },
135 	{ DOSPTYP_NTFS,		G_PART_ALIAS_MS_NTFS },
136 	{ DOSPTYP_FAT32,	G_PART_ALIAS_MS_FAT32 },
137 	{ DOSPTYP_LINSWP,	G_PART_ALIAS_LINUX_SWAP },
138 	{ DOSPTYP_LINUX,	G_PART_ALIAS_LINUX_DATA },
139 	{ DOSPTYP_LINLVM,	G_PART_ALIAS_LINUX_LVM },
140 	{ DOSPTYP_LINRAID,	G_PART_ALIAS_LINUX_RAID },
141 };
142 
143 static void ebr_set_chs(struct g_part_table *, uint32_t, u_char *, u_char *,
144     u_char *);
145 
146 static void
147 ebr_entry_decode(const char *p, struct dos_partition *ent)
148 {
149 	ent->dp_flag = p[0];
150 	ent->dp_shd = p[1];
151 	ent->dp_ssect = p[2];
152 	ent->dp_scyl = p[3];
153 	ent->dp_typ = p[4];
154 	ent->dp_ehd = p[5];
155 	ent->dp_esect = p[6];
156 	ent->dp_ecyl = p[7];
157 	ent->dp_start = le32dec(p + 8);
158 	ent->dp_size = le32dec(p + 12);
159 }
160 
161 static void
162 ebr_entry_link(struct g_part_table *table, uint32_t start, uint32_t end,
163    u_char *buf)
164 {
165 
166 	buf[0] = 0 /* dp_flag */;
167 	ebr_set_chs(table, start, &buf[3] /* dp_scyl */, &buf[1] /* dp_shd */,
168 	    &buf[2] /* dp_ssect */);
169 	buf[4] = 5 /* dp_typ */;
170 	ebr_set_chs(table, end, &buf[7] /* dp_ecyl */, &buf[5] /* dp_ehd */,
171 	    &buf[6] /* dp_esect */);
172 	le32enc(buf + 8, start);
173 	le32enc(buf + 12, end - start + 1);
174 }
175 
176 static int
177 ebr_parse_type(const char *type, u_char *dp_typ)
178 {
179 	const char *alias;
180 	char *endp;
181 	long lt;
182 	int i;
183 
184 	if (type[0] == '!') {
185 		lt = strtol(type + 1, &endp, 0);
186 		if (type[1] == '\0' || *endp != '\0' || lt <= 0 || lt >= 256)
187 			return (EINVAL);
188 		*dp_typ = (u_char)lt;
189 		return (0);
190 	}
191 	for (i = 0;
192 	    i < sizeof(ebr_alias_match) / sizeof(ebr_alias_match[0]); i++) {
193 		alias = g_part_alias_name(ebr_alias_match[i].alias);
194 		if (strcasecmp(type, alias) == 0) {
195 			*dp_typ = ebr_alias_match[i].typ;
196 			return (0);
197 		}
198 	}
199 	return (EINVAL);
200 }
201 
202 
203 static void
204 ebr_set_chs(struct g_part_table *table, uint32_t lba, u_char *cylp, u_char *hdp,
205     u_char *secp)
206 {
207 	uint32_t cyl, hd, sec;
208 
209 	sec = lba % table->gpt_sectors + 1;
210 	lba /= table->gpt_sectors;
211 	hd = lba % table->gpt_heads;
212 	lba /= table->gpt_heads;
213 	cyl = lba;
214 	if (cyl > 1023)
215 		sec = hd = cyl = ~0;
216 
217 	*cylp = cyl & 0xff;
218 	*hdp = hd & 0xff;
219 	*secp = (sec & 0x3f) | ((cyl >> 2) & 0xc0);
220 }
221 
222 static int
223 ebr_align(struct g_part_table *basetable, uint32_t *start, uint32_t *size)
224 {
225 	uint32_t sectors;
226 
227 	sectors = basetable->gpt_sectors;
228 	if (*size < 2 * sectors)
229 		return (EINVAL);
230 	if (*start % sectors) {
231 		*size += (*start % sectors) - sectors;
232 		*start -= (*start % sectors) - sectors;
233 	}
234 	if (*size % sectors)
235 		*size -= (*size % sectors);
236 	if (*size < 2 * sectors)
237 		return (EINVAL);
238 	return (0);
239 }
240 
241 
242 static int
243 g_part_ebr_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
244     struct g_part_parms *gpp)
245 {
246 	struct g_provider *pp;
247 	struct g_part_ebr_entry *entry;
248 	uint32_t start, size;
249 
250 	if (gpp->gpp_parms & G_PART_PARM_LABEL)
251 		return (EINVAL);
252 
253 	pp = LIST_FIRST(&basetable->gpt_gp->consumer)->provider;
254 	entry = (struct g_part_ebr_entry *)baseentry;
255 	start = gpp->gpp_start;
256 	size = gpp->gpp_size;
257 	if (ebr_align(basetable, &start, &size) != 0)
258 		return (EINVAL);
259 	if (baseentry->gpe_deleted)
260 		bzero(&entry->ent, sizeof(entry->ent));
261 
262 	KASSERT(baseentry->gpe_start <= start, ("%s", __func__));
263 	KASSERT(baseentry->gpe_end >= start + size - 1, ("%s", __func__));
264 	baseentry->gpe_index = (start / basetable->gpt_sectors) + 1;
265 	baseentry->gpe_offset =
266 	    (off_t)(start + basetable->gpt_sectors) * pp->sectorsize;
267 	baseentry->gpe_start = start;
268 	baseentry->gpe_end = start + size - 1;
269 	entry->ent.dp_start = basetable->gpt_sectors;
270 	entry->ent.dp_size = size - basetable->gpt_sectors;
271 	ebr_set_chs(basetable, entry->ent.dp_start, &entry->ent.dp_scyl,
272 	    &entry->ent.dp_shd, &entry->ent.dp_ssect);
273 	ebr_set_chs(basetable, baseentry->gpe_end, &entry->ent.dp_ecyl,
274 	    &entry->ent.dp_ehd, &entry->ent.dp_esect);
275 	return (ebr_parse_type(gpp->gpp_type, &entry->ent.dp_typ));
276 }
277 
278 static int
279 g_part_ebr_create(struct g_part_table *basetable, struct g_part_parms *gpp)
280 {
281 	char type[64];
282 	struct g_consumer *cp;
283 	struct g_provider *pp;
284 	uint32_t msize;
285 	int error;
286 
287 	pp = gpp->gpp_provider;
288 
289 	if (pp->sectorsize < EBRSIZE)
290 		return (ENOSPC);
291 	if (pp->sectorsize > 4096)
292 		return (ENXIO);
293 
294 	/* Check that we have a parent and that it's a MBR. */
295 	if (basetable->gpt_depth == 0)
296 		return (ENXIO);
297 	cp = LIST_FIRST(&pp->consumers);
298 	error = g_getattr("PART::scheme", cp, &type);
299 	if (error != 0)
300 		return (error);
301 	if (strcmp(type, "MBR") != 0)
302 		return (ENXIO);
303 	error = g_getattr("PART::type", cp, &type);
304 	if (error != 0)
305 		return (error);
306 	if (strcmp(type, "ebr") != 0)
307 		return (ENXIO);
308 
309 	msize = MIN(pp->mediasize / pp->sectorsize, UINT32_MAX);
310 	basetable->gpt_first = 0;
311 	basetable->gpt_last = msize - 1;
312 	basetable->gpt_entries = msize / basetable->gpt_sectors;
313 	return (0);
314 }
315 
316 static int
317 g_part_ebr_destroy(struct g_part_table *basetable, struct g_part_parms *gpp)
318 {
319 
320 	/* Wipe the first sector to clear the partitioning. */
321 	basetable->gpt_smhead |= 1;
322 	return (0);
323 }
324 
325 static void
326 g_part_ebr_dumpconf(struct g_part_table *table, struct g_part_entry *baseentry,
327     struct sbuf *sb, const char *indent)
328 {
329 	struct g_part_ebr_entry *entry;
330 
331 	entry = (struct g_part_ebr_entry *)baseentry;
332 	if (indent == NULL) {
333 		/* conftxt: libdisk compatibility */
334 		sbuf_printf(sb, " xs MBREXT xt %u", entry->ent.dp_typ);
335 	} else if (entry != NULL) {
336 		/* confxml: partition entry information */
337 		sbuf_printf(sb, "%s<rawtype>%u</rawtype>\n", indent,
338 		    entry->ent.dp_typ);
339 		if (entry->ent.dp_flag & 0x80)
340 			sbuf_printf(sb, "%s<attrib>active</attrib>\n", indent);
341 	} else {
342 		/* confxml: scheme information */
343 	}
344 }
345 
346 static int
347 g_part_ebr_dumpto(struct g_part_table *table, struct g_part_entry *baseentry)
348 {
349 	struct g_part_ebr_entry *entry;
350 
351 	/* Allow dumping to a FreeBSD partition or Linux swap partition only. */
352 	entry = (struct g_part_ebr_entry *)baseentry;
353 	return ((entry->ent.dp_typ == DOSPTYP_386BSD ||
354 	    entry->ent.dp_typ == DOSPTYP_LINSWP) ? 1 : 0);
355 }
356 
357 #if defined(GEOM_PART_EBR_COMPAT)
358 static void
359 g_part_ebr_fullname(struct g_part_table *table, struct g_part_entry *entry,
360     struct sbuf *sb, const char *pfx)
361 {
362 	struct g_part_entry *iter;
363 	u_int idx;
364 
365 	idx = 5;
366 	LIST_FOREACH(iter, &table->gpt_entry, gpe_entry) {
367 		if (iter == entry)
368 			break;
369 		idx++;
370 	}
371 	sbuf_printf(sb, "%.*s%u", (int)strlen(pfx) - 1, pfx, idx);
372 }
373 #endif
374 
375 static int
376 g_part_ebr_modify(struct g_part_table *basetable,
377     struct g_part_entry *baseentry, struct g_part_parms *gpp)
378 {
379 	struct g_part_ebr_entry *entry;
380 
381 	if (gpp->gpp_parms & G_PART_PARM_LABEL)
382 		return (EINVAL);
383 
384 	entry = (struct g_part_ebr_entry *)baseentry;
385 	if (gpp->gpp_parms & G_PART_PARM_TYPE)
386 		return (ebr_parse_type(gpp->gpp_type, &entry->ent.dp_typ));
387 	return (0);
388 }
389 
390 static int
391 g_part_ebr_resize(struct g_part_table *basetable,
392     struct g_part_entry *baseentry, struct g_part_parms *gpp)
393 {
394 	struct g_provider *pp;
395 
396 	if (baseentry != NULL)
397 		return (EOPNOTSUPP);
398 	pp = LIST_FIRST(&basetable->gpt_gp->consumer)->provider;
399 	basetable->gpt_last = MIN(pp->mediasize / pp->sectorsize,
400 	    UINT32_MAX) - 1;
401 	return (0);
402 }
403 
404 static const char *
405 g_part_ebr_name(struct g_part_table *table, struct g_part_entry *entry,
406     char *buf, size_t bufsz)
407 {
408 
409 	snprintf(buf, bufsz, "+%08u", entry->gpe_index);
410 	return (buf);
411 }
412 
413 static int
414 g_part_ebr_precheck(struct g_part_table *table, enum g_part_ctl req,
415     struct g_part_parms *gpp)
416 {
417 #if defined(GEOM_PART_EBR_COMPAT)
418 	if (req == G_PART_CTL_DESTROY)
419 		return (0);
420 	return (ECANCELED);
421 #else
422 	/*
423 	 * The index is a function of the start of the partition.
424 	 * This is not something the user can override, nor is it
425 	 * something the common code will do right. We can set the
426 	 * index now so that we get what we need.
427 	 */
428 	if (req == G_PART_CTL_ADD)
429 		gpp->gpp_index = (gpp->gpp_start / table->gpt_sectors) + 1;
430 	return (0);
431 #endif
432 }
433 
434 static int
435 g_part_ebr_probe(struct g_part_table *table, struct g_consumer *cp)
436 {
437 	char type[64];
438 	struct g_provider *pp;
439 	u_char *buf, *p;
440 	int error, index, res;
441 	uint16_t magic;
442 
443 	pp = cp->provider;
444 
445 	/* Sanity-check the provider. */
446 	if (pp->sectorsize < EBRSIZE || pp->mediasize < pp->sectorsize)
447 		return (ENOSPC);
448 	if (pp->sectorsize > 4096)
449 		return (ENXIO);
450 
451 	/* Check that we have a parent and that it's a MBR. */
452 	if (table->gpt_depth == 0)
453 		return (ENXIO);
454 	error = g_getattr("PART::scheme", cp, &type);
455 	if (error != 0)
456 		return (error);
457 	if (strcmp(type, "MBR") != 0)
458 		return (ENXIO);
459 	/* Check that partition has type DOSPTYP_EBR. */
460 	error = g_getattr("PART::type", cp, &type);
461 	if (error != 0)
462 		return (error);
463 	if (strcmp(type, "ebr") != 0)
464 		return (ENXIO);
465 
466 	/* Check that there's a EBR. */
467 	buf = g_read_data(cp, 0L, pp->sectorsize, &error);
468 	if (buf == NULL)
469 		return (error);
470 
471 	/* We goto out on mismatch. */
472 	res = ENXIO;
473 
474 	magic = le16dec(buf + DOSMAGICOFFSET);
475 	if (magic != DOSMAGIC)
476 		goto out;
477 
478 	for (index = 0; index < 2; index++) {
479 		p = buf + DOSPARTOFF + index * DOSPARTSIZE;
480 		if (p[0] != 0 && p[0] != 0x80)
481 			goto out;
482 	}
483 	res = G_PART_PROBE_PRI_NORM;
484 
485  out:
486 	g_free(buf);
487 	return (res);
488 }
489 
490 static int
491 g_part_ebr_read(struct g_part_table *basetable, struct g_consumer *cp)
492 {
493 	struct dos_partition ent[2];
494 	struct g_provider *pp;
495 	struct g_part_entry *baseentry;
496 	struct g_part_ebr_table *table;
497 	struct g_part_ebr_entry *entry;
498 	u_char *buf;
499 	off_t ofs, msize;
500 	u_int lba;
501 	int error, index;
502 
503 	pp = cp->provider;
504 	table = (struct g_part_ebr_table *)basetable;
505 	msize = MIN(pp->mediasize / pp->sectorsize, UINT32_MAX);
506 
507 	lba = 0;
508 	while (1) {
509 		ofs = (off_t)lba * pp->sectorsize;
510 		buf = g_read_data(cp, ofs, pp->sectorsize, &error);
511 		if (buf == NULL)
512 			return (error);
513 
514 		ebr_entry_decode(buf + DOSPARTOFF + 0 * DOSPARTSIZE, ent + 0);
515 		ebr_entry_decode(buf + DOSPARTOFF + 1 * DOSPARTSIZE, ent + 1);
516 
517 		/* The 3rd & 4th entries should be zeroes. */
518 		if (le64dec(buf + DOSPARTOFF + 2 * DOSPARTSIZE) +
519 		    le64dec(buf + DOSPARTOFF + 3 * DOSPARTSIZE) != 0) {
520 			basetable->gpt_corrupt = 1;
521 			printf("GEOM: %s: invalid entries in the EBR ignored.\n",
522 			    pp->name);
523 		}
524 #ifndef GEOM_PART_EBR_COMPAT
525 		/* Save the first EBR, it can contain a boot code */
526 		if (lba == 0)
527 			bcopy(buf, table->ebr, sizeof(table->ebr));
528 #endif
529 		g_free(buf);
530 
531 		if (ent[0].dp_typ == 0)
532 			break;
533 
534 		if (ent[0].dp_typ == 5 && ent[1].dp_typ == 0) {
535 			lba = ent[0].dp_start;
536 			continue;
537 		}
538 
539 		index = (lba / basetable->gpt_sectors) + 1;
540 		baseentry = (struct g_part_entry *)g_part_new_entry(basetable,
541 		    index, lba, lba + ent[0].dp_start + ent[0].dp_size - 1);
542 		baseentry->gpe_offset = (off_t)(lba + ent[0].dp_start) *
543 		    pp->sectorsize;
544 		entry = (struct g_part_ebr_entry *)baseentry;
545 		entry->ent = ent[0];
546 
547 		if (ent[1].dp_typ == 0)
548 			break;
549 
550 		lba = ent[1].dp_start;
551 	}
552 
553 	basetable->gpt_entries = msize / basetable->gpt_sectors;
554 	basetable->gpt_first = 0;
555 	basetable->gpt_last = msize - 1;
556 	return (0);
557 }
558 
559 static int
560 g_part_ebr_setunset(struct g_part_table *table, struct g_part_entry *baseentry,
561     const char *attrib, unsigned int set)
562 {
563 	struct g_part_entry *iter;
564 	struct g_part_ebr_entry *entry;
565 	int changed;
566 
567 	if (baseentry == NULL)
568 		return (ENODEV);
569 	if (strcasecmp(attrib, "active") != 0)
570 		return (EINVAL);
571 
572 	/* Only one entry can have the active attribute. */
573 	LIST_FOREACH(iter, &table->gpt_entry, gpe_entry) {
574 		if (iter->gpe_deleted)
575 			continue;
576 		changed = 0;
577 		entry = (struct g_part_ebr_entry *)iter;
578 		if (iter == baseentry) {
579 			if (set && (entry->ent.dp_flag & 0x80) == 0) {
580 				entry->ent.dp_flag |= 0x80;
581 				changed = 1;
582 			} else if (!set && (entry->ent.dp_flag & 0x80)) {
583 				entry->ent.dp_flag &= ~0x80;
584 				changed = 1;
585 			}
586 		} else {
587 			if (set && (entry->ent.dp_flag & 0x80)) {
588 				entry->ent.dp_flag &= ~0x80;
589 				changed = 1;
590 			}
591 		}
592 		if (changed && !iter->gpe_created)
593 			iter->gpe_modified = 1;
594 	}
595 	return (0);
596 }
597 
598 static const char *
599 g_part_ebr_type(struct g_part_table *basetable, struct g_part_entry *baseentry,
600     char *buf, size_t bufsz)
601 {
602 	struct g_part_ebr_entry *entry;
603 	int i;
604 
605 	entry = (struct g_part_ebr_entry *)baseentry;
606 	for (i = 0;
607 	    i < sizeof(ebr_alias_match) / sizeof(ebr_alias_match[0]); i++) {
608 		if (ebr_alias_match[i].typ == entry->ent.dp_typ)
609 			return (g_part_alias_name(ebr_alias_match[i].alias));
610 	}
611 	snprintf(buf, bufsz, "!%d", entry->ent.dp_typ);
612 	return (buf);
613 }
614 
615 static int
616 g_part_ebr_write(struct g_part_table *basetable, struct g_consumer *cp)
617 {
618 #ifndef GEOM_PART_EBR_COMPAT
619 	struct g_part_ebr_table *table;
620 #endif
621 	struct g_provider *pp;
622 	struct g_part_entry *baseentry, *next;
623 	struct g_part_ebr_entry *entry;
624 	u_char *buf;
625 	u_char *p;
626 	int error;
627 
628 	pp = cp->provider;
629 	buf = g_malloc(pp->sectorsize, M_WAITOK | M_ZERO);
630 #ifndef GEOM_PART_EBR_COMPAT
631 	table = (struct g_part_ebr_table *)basetable;
632 	bcopy(table->ebr, buf, DOSPARTOFF);
633 #endif
634 	le16enc(buf + DOSMAGICOFFSET, DOSMAGIC);
635 
636 	baseentry = LIST_FIRST(&basetable->gpt_entry);
637 	while (baseentry != NULL && baseentry->gpe_deleted)
638 		baseentry = LIST_NEXT(baseentry, gpe_entry);
639 
640 	/* Wipe-out the first EBR when there are no slices. */
641 	if (baseentry == NULL) {
642 		error = g_write_data(cp, 0, buf, pp->sectorsize);
643 		goto out;
644 	}
645 
646 	/*
647 	 * If the first partition is not in LBA 0, we need to
648 	 * put a "link" EBR in LBA 0.
649 	 */
650 	if (baseentry->gpe_start != 0) {
651 		ebr_entry_link(basetable, (uint32_t)baseentry->gpe_start,
652 		    (uint32_t)baseentry->gpe_end, buf + DOSPARTOFF);
653 		error = g_write_data(cp, 0, buf, pp->sectorsize);
654 		if (error)
655 			goto out;
656 	}
657 
658 	do {
659 		entry = (struct g_part_ebr_entry *)baseentry;
660 
661 		p = buf + DOSPARTOFF;
662 		p[0] = entry->ent.dp_flag;
663 		p[1] = entry->ent.dp_shd;
664 		p[2] = entry->ent.dp_ssect;
665 		p[3] = entry->ent.dp_scyl;
666 		p[4] = entry->ent.dp_typ;
667 		p[5] = entry->ent.dp_ehd;
668 		p[6] = entry->ent.dp_esect;
669 		p[7] = entry->ent.dp_ecyl;
670 		le32enc(p + 8, entry->ent.dp_start);
671 		le32enc(p + 12, entry->ent.dp_size);
672 
673 		next = LIST_NEXT(baseentry, gpe_entry);
674 		while (next != NULL && next->gpe_deleted)
675 			next = LIST_NEXT(next, gpe_entry);
676 
677 		p += DOSPARTSIZE;
678 		if (next != NULL)
679 			ebr_entry_link(basetable, (uint32_t)next->gpe_start,
680 			    (uint32_t)next->gpe_end, p);
681 		else
682 			bzero(p, DOSPARTSIZE);
683 
684 		error = g_write_data(cp, baseentry->gpe_start * pp->sectorsize,
685 		    buf, pp->sectorsize);
686 #ifndef GEOM_PART_EBR_COMPAT
687 		if (baseentry->gpe_start == 0)
688 			bzero(buf, DOSPARTOFF);
689 #endif
690 		baseentry = next;
691 	} while (!error && baseentry != NULL);
692 
693  out:
694 	g_free(buf);
695 	return (error);
696 }
697