xref: /freebsd/sys/geom/part/g_part_apm.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
1 /*-
2  * Copyright (c) 2006-2008 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 <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/apm.h>
32 #include <sys/bio.h>
33 #include <sys/diskmbr.h>
34 #include <sys/endian.h>
35 #include <sys/kernel.h>
36 #include <sys/kobj.h>
37 #include <sys/limits.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/queue.h>
42 #include <sys/sbuf.h>
43 #include <sys/systm.h>
44 #include <sys/sysctl.h>
45 #include <geom/geom.h>
46 #include <geom/part/g_part.h>
47 
48 #include "g_part_if.h"
49 
50 FEATURE(geom_part_apm, "GEOM partitioning class for Apple-style partitions");
51 
52 struct g_part_apm_table {
53 	struct g_part_table	base;
54 	struct apm_ddr		ddr;
55 	struct apm_ent		self;
56 	int			tivo_series1;
57 };
58 
59 struct g_part_apm_entry {
60 	struct g_part_entry	base;
61 	struct apm_ent		ent;
62 };
63 
64 static int g_part_apm_add(struct g_part_table *, struct g_part_entry *,
65     struct g_part_parms *);
66 static int g_part_apm_create(struct g_part_table *, struct g_part_parms *);
67 static int g_part_apm_destroy(struct g_part_table *, struct g_part_parms *);
68 static void g_part_apm_dumpconf(struct g_part_table *, struct g_part_entry *,
69     struct sbuf *, const char *);
70 static int g_part_apm_dumpto(struct g_part_table *, struct g_part_entry *);
71 static int g_part_apm_modify(struct g_part_table *, struct g_part_entry *,
72     struct g_part_parms *);
73 static const char *g_part_apm_name(struct g_part_table *, struct g_part_entry *,
74     char *, size_t);
75 static int g_part_apm_probe(struct g_part_table *, struct g_consumer *);
76 static int g_part_apm_read(struct g_part_table *, struct g_consumer *);
77 static const char *g_part_apm_type(struct g_part_table *, struct g_part_entry *,
78     char *, size_t);
79 static int g_part_apm_write(struct g_part_table *, struct g_consumer *);
80 static int g_part_apm_resize(struct g_part_table *, struct g_part_entry *,
81     struct g_part_parms *);
82 
83 static kobj_method_t g_part_apm_methods[] = {
84 	KOBJMETHOD(g_part_add,		g_part_apm_add),
85 	KOBJMETHOD(g_part_create,	g_part_apm_create),
86 	KOBJMETHOD(g_part_destroy,	g_part_apm_destroy),
87 	KOBJMETHOD(g_part_dumpconf,	g_part_apm_dumpconf),
88 	KOBJMETHOD(g_part_dumpto,	g_part_apm_dumpto),
89 	KOBJMETHOD(g_part_modify,	g_part_apm_modify),
90 	KOBJMETHOD(g_part_resize,	g_part_apm_resize),
91 	KOBJMETHOD(g_part_name,		g_part_apm_name),
92 	KOBJMETHOD(g_part_probe,	g_part_apm_probe),
93 	KOBJMETHOD(g_part_read,		g_part_apm_read),
94 	KOBJMETHOD(g_part_type,		g_part_apm_type),
95 	KOBJMETHOD(g_part_write,	g_part_apm_write),
96 	{ 0, 0 }
97 };
98 
99 static struct g_part_scheme g_part_apm_scheme = {
100 	"APM",
101 	g_part_apm_methods,
102 	sizeof(struct g_part_apm_table),
103 	.gps_entrysz = sizeof(struct g_part_apm_entry),
104 	.gps_minent = 16,
105 	.gps_maxent = INT_MAX,
106 };
107 G_PART_SCHEME_DECLARE(g_part_apm);
108 
109 static void
110 swab(char *buf, size_t bufsz)
111 {
112 	int i;
113 	char ch;
114 
115 	for (i = 0; i < bufsz; i += 2) {
116 		ch = buf[i];
117 		buf[i] = buf[i + 1];
118 		buf[i + 1] = ch;
119 	}
120 }
121 
122 static int
123 apm_parse_type(const char *type, char *buf, size_t bufsz)
124 {
125 	const char *alias;
126 
127 	if (type[0] == '!') {
128 		type++;
129 		if (strlen(type) > bufsz)
130 			return (EINVAL);
131 		if (!strcmp(type, APM_ENT_TYPE_SELF) ||
132 		    !strcmp(type, APM_ENT_TYPE_UNUSED))
133 			return (EINVAL);
134 		strncpy(buf, type, bufsz);
135 		return (0);
136 	}
137 	alias = g_part_alias_name(G_PART_ALIAS_APPLE_BOOT);
138 	if (!strcasecmp(type, alias)) {
139 		strcpy(buf, APM_ENT_TYPE_APPLE_BOOT);
140 		return (0);
141 	}
142 	alias = g_part_alias_name(G_PART_ALIAS_APPLE_HFS);
143 	if (!strcasecmp(type, alias)) {
144 		strcpy(buf, APM_ENT_TYPE_APPLE_HFS);
145 		return (0);
146 	}
147 	alias = g_part_alias_name(G_PART_ALIAS_APPLE_UFS);
148 	if (!strcasecmp(type, alias)) {
149 		strcpy(buf, APM_ENT_TYPE_APPLE_UFS);
150 		return (0);
151 	}
152 	alias = g_part_alias_name(G_PART_ALIAS_FREEBSD_BOOT);
153 	if (!strcasecmp(type, alias)) {
154 		strcpy(buf, APM_ENT_TYPE_APPLE_BOOT);
155 		return (0);
156 	}
157 	alias = g_part_alias_name(G_PART_ALIAS_FREEBSD);
158 	if (!strcasecmp(type, alias)) {
159 		strcpy(buf, APM_ENT_TYPE_FREEBSD);
160 		return (0);
161 	}
162 	alias = g_part_alias_name(G_PART_ALIAS_FREEBSD_SWAP);
163 	if (!strcasecmp(type, alias)) {
164 		strcpy(buf, APM_ENT_TYPE_FREEBSD_SWAP);
165 		return (0);
166 	}
167 	alias = g_part_alias_name(G_PART_ALIAS_FREEBSD_UFS);
168 	if (!strcasecmp(type, alias)) {
169 		strcpy(buf, APM_ENT_TYPE_FREEBSD_UFS);
170 		return (0);
171 	}
172 	alias = g_part_alias_name(G_PART_ALIAS_FREEBSD_VINUM);
173 	if (!strcasecmp(type, alias)) {
174 		strcpy(buf, APM_ENT_TYPE_FREEBSD_VINUM);
175 		return (0);
176 	}
177 	alias = g_part_alias_name(G_PART_ALIAS_FREEBSD_ZFS);
178 	if (!strcasecmp(type, alias)) {
179 		strcpy(buf, APM_ENT_TYPE_FREEBSD_ZFS);
180 		return (0);
181 	}
182 	return (EINVAL);
183 }
184 
185 static int
186 apm_read_ent(struct g_consumer *cp, uint32_t blk, struct apm_ent *ent,
187     int tivo_series1)
188 {
189 	struct g_provider *pp;
190 	char *buf;
191 	int error;
192 
193 	pp = cp->provider;
194 	buf = g_read_data(cp, pp->sectorsize * blk, pp->sectorsize, &error);
195 	if (buf == NULL)
196 		return (error);
197 	if (tivo_series1)
198 		swab(buf, pp->sectorsize);
199 	ent->ent_sig = be16dec(buf);
200 	ent->ent_pmblkcnt = be32dec(buf + 4);
201 	ent->ent_start = be32dec(buf + 8);
202 	ent->ent_size = be32dec(buf + 12);
203 	bcopy(buf + 16, ent->ent_name, sizeof(ent->ent_name));
204 	bcopy(buf + 48, ent->ent_type, sizeof(ent->ent_type));
205 	g_free(buf);
206 	return (0);
207 }
208 
209 static int
210 g_part_apm_add(struct g_part_table *basetable, struct g_part_entry *baseentry,
211     struct g_part_parms *gpp)
212 {
213 	struct g_part_apm_entry *entry;
214 	struct g_part_apm_table *table;
215 	int error;
216 
217 	entry = (struct g_part_apm_entry *)baseentry;
218 	table = (struct g_part_apm_table *)basetable;
219 	entry->ent.ent_sig = APM_ENT_SIG;
220 	entry->ent.ent_pmblkcnt = table->self.ent_pmblkcnt;
221 	entry->ent.ent_start = gpp->gpp_start;
222 	entry->ent.ent_size = gpp->gpp_size;
223 	if (baseentry->gpe_deleted) {
224 		bzero(entry->ent.ent_type, sizeof(entry->ent.ent_type));
225 		bzero(entry->ent.ent_name, sizeof(entry->ent.ent_name));
226 	}
227 	error = apm_parse_type(gpp->gpp_type, entry->ent.ent_type,
228 	    sizeof(entry->ent.ent_type));
229 	if (error)
230 		return (error);
231 	if (gpp->gpp_parms & G_PART_PARM_LABEL) {
232 		if (strlen(gpp->gpp_label) > sizeof(entry->ent.ent_name))
233 			return (EINVAL);
234 		strncpy(entry->ent.ent_name, gpp->gpp_label,
235 		    sizeof(entry->ent.ent_name));
236 	}
237 	return (0);
238 }
239 
240 static int
241 g_part_apm_create(struct g_part_table *basetable, struct g_part_parms *gpp)
242 {
243 	struct g_provider *pp;
244 	struct g_part_apm_table *table;
245 	uint32_t last;
246 
247 	/* We don't nest, which means that our depth should be 0. */
248 	if (basetable->gpt_depth != 0)
249 		return (ENXIO);
250 
251 	table = (struct g_part_apm_table *)basetable;
252 	pp = gpp->gpp_provider;
253 	if (pp->sectorsize != 512 ||
254 	    pp->mediasize < (2 + 2 * basetable->gpt_entries) * pp->sectorsize)
255 		return (ENOSPC);
256 
257 	/* APM uses 32-bit LBAs. */
258 	last = MIN(pp->mediasize / pp->sectorsize, UINT32_MAX) - 1;
259 
260 	basetable->gpt_first = 2 + basetable->gpt_entries;
261 	basetable->gpt_last = last;
262 
263 	table->ddr.ddr_sig = APM_DDR_SIG;
264 	table->ddr.ddr_blksize = pp->sectorsize;
265 	table->ddr.ddr_blkcount = last + 1;
266 
267 	table->self.ent_sig = APM_ENT_SIG;
268 	table->self.ent_pmblkcnt = basetable->gpt_entries + 1;
269 	table->self.ent_start = 1;
270 	table->self.ent_size = table->self.ent_pmblkcnt;
271 	strcpy(table->self.ent_name, "Apple");
272 	strcpy(table->self.ent_type, APM_ENT_TYPE_SELF);
273 	return (0);
274 }
275 
276 static int
277 g_part_apm_destroy(struct g_part_table *basetable, struct g_part_parms *gpp)
278 {
279 
280 	/* Wipe the first 2 sectors to clear the partitioning. */
281 	basetable->gpt_smhead |= 3;
282 	return (0);
283 }
284 
285 static void
286 g_part_apm_dumpconf(struct g_part_table *table, struct g_part_entry *baseentry,
287     struct sbuf *sb, const char *indent)
288 {
289 	union {
290 		char name[APM_ENT_NAMELEN + 1];
291 		char type[APM_ENT_TYPELEN + 1];
292 	} u;
293 	struct g_part_apm_entry *entry;
294 
295 	entry = (struct g_part_apm_entry *)baseentry;
296 	if (indent == NULL) {
297 		/* conftxt: libdisk compatibility */
298 		sbuf_printf(sb, " xs APPLE xt %s", entry->ent.ent_type);
299 	} else if (entry != NULL) {
300 		/* confxml: partition entry information */
301 		strncpy(u.name, entry->ent.ent_name, APM_ENT_NAMELEN);
302 		u.name[APM_ENT_NAMELEN] = '\0';
303 		sbuf_printf(sb, "%s<label>%s</label>\n", indent, u.name);
304 		strncpy(u.type, entry->ent.ent_type, APM_ENT_TYPELEN);
305 		u.type[APM_ENT_TYPELEN] = '\0';
306 		sbuf_printf(sb, "%s<rawtype>%s</rawtype>\n", indent, u.type);
307 	} else {
308 		/* confxml: scheme information */
309 	}
310 }
311 
312 static int
313 g_part_apm_dumpto(struct g_part_table *table, struct g_part_entry *baseentry)
314 {
315 	struct g_part_apm_entry *entry;
316 
317 	entry = (struct g_part_apm_entry *)baseentry;
318 	return ((!strcmp(entry->ent.ent_type, APM_ENT_TYPE_FREEBSD_SWAP))
319 	    ? 1 : 0);
320 }
321 
322 static int
323 g_part_apm_modify(struct g_part_table *basetable,
324     struct g_part_entry *baseentry, struct g_part_parms *gpp)
325 {
326 	struct g_part_apm_entry *entry;
327 	int error;
328 
329 	entry = (struct g_part_apm_entry *)baseentry;
330 	if (gpp->gpp_parms & G_PART_PARM_LABEL) {
331 		if (strlen(gpp->gpp_label) > sizeof(entry->ent.ent_name))
332 			return (EINVAL);
333 	}
334 	if (gpp->gpp_parms & G_PART_PARM_TYPE) {
335 		error = apm_parse_type(gpp->gpp_type, entry->ent.ent_type,
336 		    sizeof(entry->ent.ent_type));
337 		if (error)
338 			return (error);
339 	}
340 	if (gpp->gpp_parms & G_PART_PARM_LABEL) {
341 		strncpy(entry->ent.ent_name, gpp->gpp_label,
342 		    sizeof(entry->ent.ent_name));
343 	}
344 	return (0);
345 }
346 
347 static int
348 g_part_apm_resize(struct g_part_table *basetable,
349     struct g_part_entry *baseentry, struct g_part_parms *gpp)
350 {
351 	struct g_part_apm_entry *entry;
352 
353 	entry = (struct g_part_apm_entry *)baseentry;
354 	baseentry->gpe_end = baseentry->gpe_start + gpp->gpp_size - 1;
355 	entry->ent.ent_size = gpp->gpp_size;
356 
357 	return (0);
358 }
359 
360 static const char *
361 g_part_apm_name(struct g_part_table *table, struct g_part_entry *baseentry,
362     char *buf, size_t bufsz)
363 {
364 
365 	snprintf(buf, bufsz, "s%d", baseentry->gpe_index + 1);
366 	return (buf);
367 }
368 
369 static int
370 g_part_apm_probe(struct g_part_table *basetable, struct g_consumer *cp)
371 {
372 	struct g_provider *pp;
373 	struct g_part_apm_table *table;
374 	char *buf;
375 	int error;
376 
377 	/* We don't nest, which means that our depth should be 0. */
378 	if (basetable->gpt_depth != 0)
379 		return (ENXIO);
380 
381 	table = (struct g_part_apm_table *)basetable;
382 	table->tivo_series1 = 0;
383 	pp = cp->provider;
384 
385 	/* Sanity-check the provider. */
386 	if (pp->mediasize < 4 * pp->sectorsize)
387 		return (ENOSPC);
388 
389 	/* Check that there's a Driver Descriptor Record (DDR). */
390 	buf = g_read_data(cp, 0L, pp->sectorsize, &error);
391 	if (buf == NULL)
392 		return (error);
393 	if (be16dec(buf) == APM_DDR_SIG) {
394 		/* Normal Apple DDR */
395 		table->ddr.ddr_sig = be16dec(buf);
396 		table->ddr.ddr_blksize = be16dec(buf + 2);
397 		table->ddr.ddr_blkcount = be32dec(buf + 4);
398 		g_free(buf);
399 		if (table->ddr.ddr_blksize != pp->sectorsize)
400 			return (ENXIO);
401 		if (table->ddr.ddr_blkcount > pp->mediasize / pp->sectorsize)
402 			return (ENXIO);
403 	} else {
404 		/*
405 		 * Check for Tivo drives, which have no DDR and a different
406 		 * signature.  Those whose first two bytes are 14 92 are
407 		 * Series 2 drives, and aren't supported.  Those that start
408 		 * with 92 14 are series 1 drives and are supported.
409 		 */
410 		if (be16dec(buf) != 0x9214) {
411 			/* If this is 0x1492 it could be a series 2 drive */
412 			g_free(buf);
413 			return (ENXIO);
414 		}
415 		table->ddr.ddr_sig = APM_DDR_SIG;		/* XXX */
416 		table->ddr.ddr_blksize = pp->sectorsize;	/* XXX */
417 		table->ddr.ddr_blkcount =
418 		    MIN(pp->mediasize / pp->sectorsize, UINT32_MAX);
419 		table->tivo_series1 = 1;
420 		g_free(buf);
421 	}
422 
423 	/* Check that there's a Partition Map. */
424 	error = apm_read_ent(cp, 1, &table->self, table->tivo_series1);
425 	if (error)
426 		return (error);
427 	if (table->self.ent_sig != APM_ENT_SIG)
428 		return (ENXIO);
429 	if (strcmp(table->self.ent_type, APM_ENT_TYPE_SELF))
430 		return (ENXIO);
431 	if (table->self.ent_pmblkcnt >= table->ddr.ddr_blkcount)
432 		return (ENXIO);
433 	return (G_PART_PROBE_PRI_NORM);
434 }
435 
436 static int
437 g_part_apm_read(struct g_part_table *basetable, struct g_consumer *cp)
438 {
439 	struct apm_ent ent;
440 	struct g_part_apm_entry *entry;
441 	struct g_part_apm_table *table;
442 	int error, index;
443 
444 	table = (struct g_part_apm_table *)basetable;
445 
446 	basetable->gpt_first = table->self.ent_pmblkcnt + 1;
447 	basetable->gpt_last = table->ddr.ddr_blkcount - 1;
448 	basetable->gpt_entries = table->self.ent_pmblkcnt - 1;
449 
450 	for (index = table->self.ent_pmblkcnt - 1; index > 0; index--) {
451 		error = apm_read_ent(cp, index + 1, &ent, table->tivo_series1);
452 		if (error)
453 			continue;
454 		if (!strcmp(ent.ent_type, APM_ENT_TYPE_UNUSED))
455 			continue;
456 		entry = (struct g_part_apm_entry *)g_part_new_entry(basetable,
457 		    index, ent.ent_start, ent.ent_start + ent.ent_size - 1);
458 		entry->ent = ent;
459 	}
460 
461 	return (0);
462 }
463 
464 static const char *
465 g_part_apm_type(struct g_part_table *basetable, struct g_part_entry *baseentry,
466     char *buf, size_t bufsz)
467 {
468 	struct g_part_apm_entry *entry;
469 	const char *type;
470 	size_t len;
471 
472 	entry = (struct g_part_apm_entry *)baseentry;
473 	type = entry->ent.ent_type;
474 	if (!strcmp(type, APM_ENT_TYPE_APPLE_BOOT))
475 		return (g_part_alias_name(G_PART_ALIAS_APPLE_BOOT));
476 	if (!strcmp(type, APM_ENT_TYPE_APPLE_HFS))
477 		return (g_part_alias_name(G_PART_ALIAS_APPLE_HFS));
478 	if (!strcmp(type, APM_ENT_TYPE_APPLE_UFS))
479 		return (g_part_alias_name(G_PART_ALIAS_APPLE_UFS));
480 	if (!strcmp(type, APM_ENT_TYPE_FREEBSD))
481 		return (g_part_alias_name(G_PART_ALIAS_FREEBSD));
482 	if (!strcmp(type, APM_ENT_TYPE_FREEBSD_SWAP))
483 		return (g_part_alias_name(G_PART_ALIAS_FREEBSD_SWAP));
484 	if (!strcmp(type, APM_ENT_TYPE_FREEBSD_UFS))
485 		return (g_part_alias_name(G_PART_ALIAS_FREEBSD_UFS));
486 	if (!strcmp(type, APM_ENT_TYPE_FREEBSD_VINUM))
487 		return (g_part_alias_name(G_PART_ALIAS_FREEBSD_VINUM));
488 	if (!strcmp(type, APM_ENT_TYPE_FREEBSD_ZFS))
489 		return (g_part_alias_name(G_PART_ALIAS_FREEBSD_ZFS));
490 	buf[0] = '!';
491 	len = MIN(sizeof(entry->ent.ent_type), bufsz - 2);
492 	bcopy(type, buf + 1, len);
493 	buf[len + 1] = '\0';
494 	return (buf);
495 }
496 
497 static int
498 g_part_apm_write(struct g_part_table *basetable, struct g_consumer *cp)
499 {
500 	char buf[512];
501 	struct g_part_entry *baseentry;
502 	struct g_part_apm_entry *entry;
503 	struct g_part_apm_table *table;
504 	int error, index;
505 
506 	table = (struct g_part_apm_table *)basetable;
507 	/*
508 	 * Tivo Series 1 disk partitions are currently read-only.
509 	 */
510 	if (table->tivo_series1)
511 		return (EOPNOTSUPP);
512 	bzero(buf, sizeof(buf));
513 
514 	/* Write the DDR and 'self' entry only when we're newly created. */
515 	if (basetable->gpt_created) {
516 		be16enc(buf, table->ddr.ddr_sig);
517 		be16enc(buf + 2, table->ddr.ddr_blksize);
518 		be32enc(buf + 4, table->ddr.ddr_blkcount);
519 		error = g_write_data(cp, 0, buf, sizeof(buf));
520 		if (error)
521 			return (error);
522 	}
523 
524 	be16enc(buf, table->self.ent_sig);
525 	be16enc(buf + 2, 0);
526 	be32enc(buf + 4, table->self.ent_pmblkcnt);
527 
528 	if (basetable->gpt_created) {
529 		be32enc(buf + 8, table->self.ent_start);
530 		be32enc(buf + 12, table->self.ent_size);
531 		bcopy(table->self.ent_name, buf + 16,
532 		    sizeof(table->self.ent_name));
533 		bcopy(table->self.ent_type, buf + 48,
534 		    sizeof(table->self.ent_type));
535 		error = g_write_data(cp, 512, buf, sizeof(buf));
536 		if (error)
537 			return (error);
538 	}
539 
540 	baseentry = LIST_FIRST(&basetable->gpt_entry);
541 	for (index = 1; index <= basetable->gpt_entries; index++) {
542 		entry = (baseentry != NULL && index == baseentry->gpe_index)
543 		    ? (struct g_part_apm_entry *)baseentry : NULL;
544 		if (entry != NULL && !baseentry->gpe_deleted) {
545 			be32enc(buf + 8, entry->ent.ent_start);
546 			be32enc(buf + 12, entry->ent.ent_size);
547 			bcopy(entry->ent.ent_name, buf + 16,
548 			    sizeof(entry->ent.ent_name));
549 			bcopy(entry->ent.ent_type, buf + 48,
550 			    sizeof(entry->ent.ent_type));
551 		} else {
552 			bzero(buf + 8, 4 + 4 + 32 + 32);
553 			strcpy(buf + 48, APM_ENT_TYPE_UNUSED);
554 		}
555 		error = g_write_data(cp, (index + 1) * 512, buf, sizeof(buf));
556 		if (error)
557 			return (error);
558 		if (entry != NULL)
559 			baseentry = LIST_NEXT(baseentry, gpe_entry);
560 	}
561 
562 	return (0);
563 }
564