xref: /freebsd/sys/geom/mirror/g_mirror.h (revision 4f52dfbb)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #ifndef	_G_MIRROR_H_
32 #define	_G_MIRROR_H_
33 
34 #include <sys/endian.h>
35 #include <sys/md5.h>
36 
37 #define	G_MIRROR_CLASS_NAME	"MIRROR"
38 
39 #define	G_MIRROR_MAGIC		"GEOM::MIRROR"
40 /*
41  * Version history:
42  * 0 - Initial version number.
43  * 1 - Added 'prefer' balance algorithm.
44  * 2 - Added md_genid field to metadata.
45  * 3 - Added md_provsize field to metadata.
46  * 4 - Added 'no failure synchronization' flag.
47  */
48 #define	G_MIRROR_VERSION	4
49 
50 #define	G_MIRROR_BALANCE_NONE		0
51 #define	G_MIRROR_BALANCE_ROUND_ROBIN	1
52 #define	G_MIRROR_BALANCE_LOAD		2
53 #define	G_MIRROR_BALANCE_SPLIT		3
54 #define	G_MIRROR_BALANCE_PREFER		4
55 #define	G_MIRROR_BALANCE_MIN		G_MIRROR_BALANCE_NONE
56 #define	G_MIRROR_BALANCE_MAX		G_MIRROR_BALANCE_PREFER
57 
58 #define	G_MIRROR_DISK_FLAG_DIRTY		0x0000000000000001ULL
59 #define	G_MIRROR_DISK_FLAG_SYNCHRONIZING	0x0000000000000002ULL
60 #define	G_MIRROR_DISK_FLAG_FORCE_SYNC		0x0000000000000004ULL
61 #define	G_MIRROR_DISK_FLAG_INACTIVE		0x0000000000000008ULL
62 #define	G_MIRROR_DISK_FLAG_HARDCODED		0x0000000000000010ULL
63 #define	G_MIRROR_DISK_FLAG_BROKEN		0x0000000000000020ULL
64 #define	G_MIRROR_DISK_FLAG_CANDELETE		0x0000000000000040ULL
65 
66 /* Per-disk flags which are recorded in on-disk metadata. */
67 #define	G_MIRROR_DISK_FLAG_MASK		(G_MIRROR_DISK_FLAG_DIRTY |	\
68 					 G_MIRROR_DISK_FLAG_SYNCHRONIZING | \
69 					 G_MIRROR_DISK_FLAG_FORCE_SYNC | \
70 					 G_MIRROR_DISK_FLAG_INACTIVE | \
71 					 G_MIRROR_DISK_FLAG_CANDELETE)
72 
73 #define	G_MIRROR_DEVICE_FLAG_NOAUTOSYNC	0x0000000000000001ULL
74 #define	G_MIRROR_DEVICE_FLAG_NOFAILSYNC	0x0000000000000002ULL
75 
76 /* Mirror flags which are recorded in on-disk metadata. */
77 #define	G_MIRROR_DEVICE_FLAG_MASK	(G_MIRROR_DEVICE_FLAG_NOAUTOSYNC | \
78 					 G_MIRROR_DEVICE_FLAG_NOFAILSYNC)
79 
80 #ifdef _KERNEL
81 extern int g_mirror_debug;
82 
83 #define	G_MIRROR_DEBUG(lvl, ...)	do {				\
84 	if (g_mirror_debug >= (lvl)) {					\
85 		printf("GEOM_MIRROR");					\
86 		if (g_mirror_debug > 0)					\
87 			printf("[%u]", lvl);				\
88 		printf(": ");						\
89 		printf(__VA_ARGS__);					\
90 		printf("\n");						\
91 	}								\
92 } while (0)
93 #define	G_MIRROR_LOGREQ(lvl, bp, ...)	do {				\
94 	if (g_mirror_debug >= (lvl)) {					\
95 		printf("GEOM_MIRROR");					\
96 		if (g_mirror_debug > 0)					\
97 			printf("[%u]", lvl);				\
98 		printf(": ");						\
99 		printf(__VA_ARGS__);					\
100 		printf(" ");						\
101 		g_print_bio(bp);					\
102 		printf("\n");						\
103 	}								\
104 } while (0)
105 
106 #define	G_MIRROR_BIO_FLAG_REGULAR	0x01
107 #define	G_MIRROR_BIO_FLAG_SYNC		0x02
108 
109 /*
110  * Informations needed for synchronization.
111  */
112 struct g_mirror_disk_sync {
113 	struct g_consumer *ds_consumer;	/* Consumer connected to our mirror. */
114 	off_t		  ds_offset;	/* Offset of next request to send. */
115 	off_t		  ds_offset_done; /* Offset of already synchronized
116 					   region. */
117 	time_t		  ds_update_ts; /* Time of last metadata update. */
118 	u_int		  ds_syncid;	/* Disk's synchronization ID. */
119 	u_int		  ds_inflight;	/* Number of in-flight sync requests. */
120 	struct bio	**ds_bios;	/* BIOs for synchronization I/O. */
121 };
122 
123 /*
124  * Informations needed for synchronization.
125  */
126 struct g_mirror_device_sync {
127 	struct g_geom	*ds_geom;	/* Synchronization geom. */
128 	u_int		 ds_ndisks;	/* Number of disks in SYNCHRONIZING
129 					   state. */
130 };
131 
132 #define	G_MIRROR_DISK_STATE_NONE		0
133 #define	G_MIRROR_DISK_STATE_NEW			1
134 #define	G_MIRROR_DISK_STATE_ACTIVE		2
135 #define	G_MIRROR_DISK_STATE_STALE		3
136 #define	G_MIRROR_DISK_STATE_SYNCHRONIZING	4
137 #define	G_MIRROR_DISK_STATE_DISCONNECTED	5
138 #define	G_MIRROR_DISK_STATE_DESTROY		6
139 struct g_mirror_disk {
140 	uint32_t	 d_id;		/* Disk ID. */
141 	struct g_consumer *d_consumer;	/* Consumer. */
142 	struct g_mirror_softc	*d_softc; /* Back-pointer to softc. */
143 	int		 d_state;	/* Disk state. */
144 	u_int		 d_priority;	/* Disk priority. */
145 	u_int		 load;		/* Averaged queue length */
146 	off_t		 d_last_offset;	/* Last read offset */
147 	uint64_t	 d_flags;	/* Additional flags. */
148 	u_int		 d_genid;	/* Disk's generation ID. */
149 	struct g_mirror_disk_sync d_sync;/* Sync information. */
150 	LIST_ENTRY(g_mirror_disk) d_next;
151 };
152 #define	d_name	d_consumer->provider->name
153 
154 #define	G_MIRROR_EVENT_DONTWAIT	0x1
155 #define	G_MIRROR_EVENT_WAIT	0x2
156 #define	G_MIRROR_EVENT_DEVICE	0x4
157 #define	G_MIRROR_EVENT_DONE	0x8
158 struct g_mirror_event {
159 	struct g_mirror_disk	*e_disk;
160 	int			 e_state;
161 	int			 e_flags;
162 	int			 e_error;
163 	TAILQ_ENTRY(g_mirror_event) e_next;
164 };
165 
166 #define	G_MIRROR_DEVICE_FLAG_DESTROY	0x0100000000000000ULL
167 #define	G_MIRROR_DEVICE_FLAG_DRAIN	0x0200000000000000ULL
168 #define	G_MIRROR_DEVICE_FLAG_CLOSEWAIT	0x0400000000000000ULL
169 #define	G_MIRROR_DEVICE_FLAG_TASTING	0x0800000000000000ULL
170 #define	G_MIRROR_DEVICE_FLAG_WIPE	0x1000000000000000ULL
171 
172 #define	G_MIRROR_DEVICE_STATE_STARTING		0
173 #define	G_MIRROR_DEVICE_STATE_RUNNING		1
174 
175 #define	G_MIRROR_TYPE_MANUAL	0
176 #define	G_MIRROR_TYPE_AUTOMATIC	1
177 
178 /* Bump syncid on first write. */
179 #define	G_MIRROR_BUMP_SYNCID		0x1
180 /* Bump genid immediately. */
181 #define	G_MIRROR_BUMP_GENID		0x2
182 /* Bump syncid immediately. */
183 #define	G_MIRROR_BUMP_SYNCID_NOW	0x4
184 struct g_mirror_softc {
185 	u_int		sc_type;	/* Device type (manual/automatic). */
186 	u_int		sc_state;	/* Device state. */
187 	uint32_t	sc_slice;	/* Slice size. */
188 	uint8_t		sc_balance;	/* Balance algorithm. */
189 	uint64_t	sc_mediasize;	/* Device size. */
190 	uint32_t	sc_sectorsize;	/* Sector size. */
191 	uint64_t	sc_flags;	/* Additional flags. */
192 
193 	struct g_geom	*sc_geom;
194 	struct g_provider *sc_provider;
195 	int		sc_provider_open;
196 
197 	uint32_t	sc_id;		/* Mirror unique ID. */
198 
199 	struct sx	 sc_lock;
200 	struct bio_queue sc_queue;
201 	struct mtx	 sc_queue_mtx;
202 	struct proc	*sc_worker;
203 	struct bio_queue sc_inflight; /* In-flight regular write requests. */
204 	struct bio_queue sc_regular_delayed; /* Delayed I/O requests due to
205 						collision with sync requests. */
206 	struct bio_queue sc_sync_delayed; /* Delayed sync requests due to
207 					     collision with regular requests. */
208 
209 	LIST_HEAD(, g_mirror_disk) sc_disks;
210 	u_int		sc_ndisks;	/* Number of disks. */
211 	struct g_mirror_disk *sc_hint;
212 
213 	u_int		sc_genid;	/* Generation ID. */
214 	u_int		sc_syncid;	/* Synchronization ID. */
215 	int		sc_bump_id;
216 	struct g_mirror_device_sync sc_sync;
217 	int		sc_idle;	/* DIRTY flags removed. */
218 	time_t		sc_last_write;
219 	u_int		sc_writes;
220 	u_int		sc_refcnt;	/* Number of softc references */
221 
222 	TAILQ_HEAD(, g_mirror_event) sc_events;
223 	struct mtx	sc_events_mtx;
224 
225 	struct callout	sc_callout;
226 
227 	struct root_hold_token *sc_rootmount;
228 
229 	struct mtx	 sc_done_mtx;
230 };
231 #define	sc_name	sc_geom->name
232 
233 struct g_mirror_metadata;
234 
235 u_int g_mirror_ndisks(struct g_mirror_softc *sc, int state);
236 struct g_geom * g_mirror_create(struct g_class *mp,
237     const struct g_mirror_metadata *md, u_int type);
238 #define	G_MIRROR_DESTROY_SOFT		0
239 #define	G_MIRROR_DESTROY_DELAYED	1
240 #define	G_MIRROR_DESTROY_HARD		2
241 int g_mirror_destroy(struct g_mirror_softc *sc, int how);
242 int g_mirror_event_send(void *arg, int state, int flags);
243 struct g_mirror_metadata;
244 int g_mirror_add_disk(struct g_mirror_softc *sc, struct g_provider *pp,
245     struct g_mirror_metadata *md);
246 int g_mirror_read_metadata(struct g_consumer *cp, struct g_mirror_metadata *md);
247 void g_mirror_fill_metadata(struct g_mirror_softc *sc,
248     struct g_mirror_disk *disk, struct g_mirror_metadata *md);
249 void g_mirror_update_metadata(struct g_mirror_disk *disk);
250 
251 g_ctl_req_t g_mirror_config;
252 #endif	/* _KERNEL */
253 
254 struct g_mirror_metadata {
255 	char		md_magic[16];	/* Magic value. */
256 	uint32_t	md_version;	/* Version number. */
257 	char		md_name[16];	/* Mirror name. */
258 	uint32_t	md_mid;		/* Mirror unique ID. */
259 	uint32_t	md_did;		/* Disk unique ID. */
260 	uint8_t		md_all;		/* Number of disks in mirror. */
261 	uint32_t	md_genid;	/* Generation ID. */
262 	uint32_t	md_syncid;	/* Synchronization ID. */
263 	uint8_t		md_priority;	/* Disk priority. */
264 	uint32_t	md_slice;	/* Slice size. */
265 	uint8_t		md_balance;	/* Balance type. */
266 	uint64_t	md_mediasize;	/* Size of the smallest
267 					   disk in mirror. */
268 	uint32_t	md_sectorsize;	/* Sector size. */
269 	uint64_t	md_sync_offset;	/* Synchronized offset. */
270 	uint64_t	md_mflags;	/* Additional mirror flags. */
271 	uint64_t	md_dflags;	/* Additional disk flags. */
272 	char		md_provider[16]; /* Hardcoded provider. */
273 	uint64_t	md_provsize;	/* Provider's size. */
274 	u_char		md_hash[16];	/* MD5 hash. */
275 };
276 static __inline void
277 mirror_metadata_encode(struct g_mirror_metadata *md, u_char *data)
278 {
279 	MD5_CTX ctx;
280 
281 	bcopy(md->md_magic, data, 16);
282 	le32enc(data + 16, md->md_version);
283 	bcopy(md->md_name, data + 20, 16);
284 	le32enc(data + 36, md->md_mid);
285 	le32enc(data + 40, md->md_did);
286 	*(data + 44) = md->md_all;
287 	le32enc(data + 45, md->md_genid);
288 	le32enc(data + 49, md->md_syncid);
289 	*(data + 53) = md->md_priority;
290 	le32enc(data + 54, md->md_slice);
291 	*(data + 58) = md->md_balance;
292 	le64enc(data + 59, md->md_mediasize);
293 	le32enc(data + 67, md->md_sectorsize);
294 	le64enc(data + 71, md->md_sync_offset);
295 	le64enc(data + 79, md->md_mflags);
296 	le64enc(data + 87, md->md_dflags);
297 	bcopy(md->md_provider, data + 95, 16);
298 	le64enc(data + 111, md->md_provsize);
299 	MD5Init(&ctx);
300 	MD5Update(&ctx, data, 119);
301 	MD5Final(md->md_hash, &ctx);
302 	bcopy(md->md_hash, data + 119, 16);
303 }
304 static __inline int
305 mirror_metadata_decode_v0v1(const u_char *data, struct g_mirror_metadata *md)
306 {
307 	MD5_CTX ctx;
308 
309 	bcopy(data + 20, md->md_name, 16);
310 	md->md_mid = le32dec(data + 36);
311 	md->md_did = le32dec(data + 40);
312 	md->md_all = *(data + 44);
313 	md->md_syncid = le32dec(data + 45);
314 	md->md_priority = *(data + 49);
315 	md->md_slice = le32dec(data + 50);
316 	md->md_balance = *(data + 54);
317 	md->md_mediasize = le64dec(data + 55);
318 	md->md_sectorsize = le32dec(data + 63);
319 	md->md_sync_offset = le64dec(data + 67);
320 	md->md_mflags = le64dec(data + 75);
321 	md->md_dflags = le64dec(data + 83);
322 	bcopy(data + 91, md->md_provider, 16);
323 	bcopy(data + 107, md->md_hash, 16);
324 	MD5Init(&ctx);
325 	MD5Update(&ctx, data, 107);
326 	MD5Final(md->md_hash, &ctx);
327 	if (bcmp(md->md_hash, data + 107, 16) != 0)
328 		return (EINVAL);
329 
330 	/* New fields. */
331 	md->md_genid = 0;
332 	md->md_provsize = 0;
333 
334 	return (0);
335 }
336 static __inline int
337 mirror_metadata_decode_v2(const u_char *data, struct g_mirror_metadata *md)
338 {
339 	MD5_CTX ctx;
340 
341 	bcopy(data + 20, md->md_name, 16);
342 	md->md_mid = le32dec(data + 36);
343 	md->md_did = le32dec(data + 40);
344 	md->md_all = *(data + 44);
345 	md->md_genid = le32dec(data + 45);
346 	md->md_syncid = le32dec(data + 49);
347 	md->md_priority = *(data + 53);
348 	md->md_slice = le32dec(data + 54);
349 	md->md_balance = *(data + 58);
350 	md->md_mediasize = le64dec(data + 59);
351 	md->md_sectorsize = le32dec(data + 67);
352 	md->md_sync_offset = le64dec(data + 71);
353 	md->md_mflags = le64dec(data + 79);
354 	md->md_dflags = le64dec(data + 87);
355 	bcopy(data + 95, md->md_provider, 16);
356 	bcopy(data + 111, md->md_hash, 16);
357 	MD5Init(&ctx);
358 	MD5Update(&ctx, data, 111);
359 	MD5Final(md->md_hash, &ctx);
360 	if (bcmp(md->md_hash, data + 111, 16) != 0)
361 		return (EINVAL);
362 
363 	/* New fields. */
364 	md->md_provsize = 0;
365 
366 	return (0);
367 }
368 static __inline int
369 mirror_metadata_decode_v3v4(const u_char *data, struct g_mirror_metadata *md)
370 {
371 	MD5_CTX ctx;
372 
373 	bcopy(data + 20, md->md_name, 16);
374 	md->md_mid = le32dec(data + 36);
375 	md->md_did = le32dec(data + 40);
376 	md->md_all = *(data + 44);
377 	md->md_genid = le32dec(data + 45);
378 	md->md_syncid = le32dec(data + 49);
379 	md->md_priority = *(data + 53);
380 	md->md_slice = le32dec(data + 54);
381 	md->md_balance = *(data + 58);
382 	md->md_mediasize = le64dec(data + 59);
383 	md->md_sectorsize = le32dec(data + 67);
384 	md->md_sync_offset = le64dec(data + 71);
385 	md->md_mflags = le64dec(data + 79);
386 	md->md_dflags = le64dec(data + 87);
387 	bcopy(data + 95, md->md_provider, 16);
388 	md->md_provsize = le64dec(data + 111);
389 	bcopy(data + 119, md->md_hash, 16);
390 	MD5Init(&ctx);
391 	MD5Update(&ctx, data, 119);
392 	MD5Final(md->md_hash, &ctx);
393 	if (bcmp(md->md_hash, data + 119, 16) != 0)
394 		return (EINVAL);
395 	return (0);
396 }
397 static __inline int
398 mirror_metadata_decode(const u_char *data, struct g_mirror_metadata *md)
399 {
400 	int error;
401 
402 	bcopy(data, md->md_magic, 16);
403 	md->md_version = le32dec(data + 16);
404 	switch (md->md_version) {
405 	case 0:
406 	case 1:
407 		error = mirror_metadata_decode_v0v1(data, md);
408 		break;
409 	case 2:
410 		error = mirror_metadata_decode_v2(data, md);
411 		break;
412 	case 3:
413 	case 4:
414 		error = mirror_metadata_decode_v3v4(data, md);
415 		break;
416 	default:
417 		error = EINVAL;
418 		break;
419 	}
420 	return (error);
421 }
422 
423 static __inline const char *
424 balance_name(u_int balance)
425 {
426 	static const char *algorithms[] = {
427 		[G_MIRROR_BALANCE_NONE] = "none",
428 		[G_MIRROR_BALANCE_ROUND_ROBIN] = "round-robin",
429 		[G_MIRROR_BALANCE_LOAD] = "load",
430 		[G_MIRROR_BALANCE_SPLIT] = "split",
431 		[G_MIRROR_BALANCE_PREFER] = "prefer",
432 		[G_MIRROR_BALANCE_MAX + 1] = "unknown"
433 	};
434 
435 	if (balance > G_MIRROR_BALANCE_MAX)
436 		balance = G_MIRROR_BALANCE_MAX + 1;
437 
438 	return (algorithms[balance]);
439 }
440 
441 static __inline int
442 balance_id(const char *name)
443 {
444 	static const char *algorithms[] = {
445 		[G_MIRROR_BALANCE_NONE] = "none",
446 		[G_MIRROR_BALANCE_ROUND_ROBIN] = "round-robin",
447 		[G_MIRROR_BALANCE_LOAD] = "load",
448 		[G_MIRROR_BALANCE_SPLIT] = "split",
449 		[G_MIRROR_BALANCE_PREFER] = "prefer"
450 	};
451 	int n;
452 
453 	for (n = G_MIRROR_BALANCE_MIN; n <= G_MIRROR_BALANCE_MAX; n++) {
454 		if (strcmp(name, algorithms[n]) == 0)
455 			return (n);
456 	}
457 	return (-1);
458 }
459 
460 static __inline void
461 mirror_metadata_dump(const struct g_mirror_metadata *md)
462 {
463 	static const char hex[] = "0123456789abcdef";
464 	char hash[16 * 2 + 1];
465 	u_int i;
466 
467 	printf("     magic: %s\n", md->md_magic);
468 	printf("   version: %u\n", (u_int)md->md_version);
469 	printf("      name: %s\n", md->md_name);
470 	printf("       mid: %u\n", (u_int)md->md_mid);
471 	printf("       did: %u\n", (u_int)md->md_did);
472 	printf("       all: %u\n", (u_int)md->md_all);
473 	printf("     genid: %u\n", (u_int)md->md_genid);
474 	printf("    syncid: %u\n", (u_int)md->md_syncid);
475 	printf("  priority: %u\n", (u_int)md->md_priority);
476 	printf("     slice: %u\n", (u_int)md->md_slice);
477 	printf("   balance: %s\n", balance_name((u_int)md->md_balance));
478 	printf(" mediasize: %jd\n", (intmax_t)md->md_mediasize);
479 	printf("sectorsize: %u\n", (u_int)md->md_sectorsize);
480 	printf("syncoffset: %jd\n", (intmax_t)md->md_sync_offset);
481 	printf("    mflags:");
482 	if (md->md_mflags == 0)
483 		printf(" NONE");
484 	else {
485 		if ((md->md_mflags & G_MIRROR_DEVICE_FLAG_NOFAILSYNC) != 0)
486 			printf(" NOFAILSYNC");
487 		if ((md->md_mflags & G_MIRROR_DEVICE_FLAG_NOAUTOSYNC) != 0)
488 			printf(" NOAUTOSYNC");
489 	}
490 	printf("\n");
491 	printf("    dflags:");
492 	if (md->md_dflags == 0)
493 		printf(" NONE");
494 	else {
495 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_DIRTY) != 0)
496 			printf(" DIRTY");
497 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_SYNCHRONIZING) != 0)
498 			printf(" SYNCHRONIZING");
499 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_FORCE_SYNC) != 0)
500 			printf(" FORCE_SYNC");
501 		if ((md->md_dflags & G_MIRROR_DISK_FLAG_INACTIVE) != 0)
502 			printf(" INACTIVE");
503 	}
504 	printf("\n");
505 	printf("hcprovider: %s\n", md->md_provider);
506 	printf("  provsize: %ju\n", (uintmax_t)md->md_provsize);
507 	bzero(hash, sizeof(hash));
508 	for (i = 0; i < 16; i++) {
509 		hash[i * 2] = hex[md->md_hash[i] >> 4];
510 		hash[i * 2 + 1] = hex[md->md_hash[i] & 0x0f];
511 	}
512 	printf("  MD5 hash: %s\n", hash);
513 }
514 #endif	/* !_G_MIRROR_H_ */
515