xref: /netbsd-src/sys/dev/dksubr.c (revision 6a493d6bc668897c91594964a732d38505b70cbb)
1 /* $NetBSD: dksubr.c,v 1.48 2013/05/29 23:37:10 christos Exp $ */
2 
3 /*-
4  * Copyright (c) 1996, 1997, 1998, 1999, 2002, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe and Roland C. Dowdeswell.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.48 2013/05/29 23:37:10 christos Exp $");
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/stat.h>
38 #include <sys/proc.h>
39 #include <sys/ioctl.h>
40 #include <sys/device.h>
41 #include <sys/disk.h>
42 #include <sys/disklabel.h>
43 #include <sys/buf.h>
44 #include <sys/bufq.h>
45 #include <sys/vnode.h>
46 #include <sys/fcntl.h>
47 #include <sys/namei.h>
48 
49 #include <dev/dkvar.h>
50 
51 int	dkdebug = 0;
52 
53 #ifdef DEBUG
54 #define DKDB_FOLLOW	0x1
55 #define DKDB_INIT	0x2
56 #define DKDB_VNODE	0x4
57 
58 #define IFDEBUG(x,y)		if (dkdebug & (x)) y
59 #define DPRINTF(x,y)		IFDEBUG(x, printf y)
60 #define DPRINTF_FOLLOW(y)	DPRINTF(DKDB_FOLLOW, y)
61 #else
62 #define IFDEBUG(x,y)
63 #define DPRINTF(x,y)
64 #define DPRINTF_FOLLOW(y)
65 #endif
66 
67 #define DKLABELDEV(dev)	\
68 	(MAKEDISKDEV(major((dev)), DISKUNIT((dev)), RAW_PART))
69 
70 static void	dk_makedisklabel(struct dk_intf *, struct dk_softc *);
71 
72 void
73 dk_sc_init(struct dk_softc *dksc, const char *xname)
74 {
75 
76 	memset(dksc, 0x0, sizeof(*dksc));
77 	strncpy(dksc->sc_xname, xname, DK_XNAME_SIZE);
78 	dksc->sc_dkdev.dk_name = dksc->sc_xname;
79 }
80 
81 /* ARGSUSED */
82 int
83 dk_open(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
84     int flags, int fmt, struct lwp *l)
85 {
86 	struct	disklabel *lp = dksc->sc_dkdev.dk_label;
87 	int	part = DISKPART(dev);
88 	int	pmask = 1 << part;
89 	int	ret = 0;
90 	struct disk *dk = &dksc->sc_dkdev;
91 
92 	DPRINTF_FOLLOW(("dk_open(%s, %p, 0x%"PRIx64", 0x%x)\n",
93 	    di->di_dkname, dksc, dev, flags));
94 
95 	mutex_enter(&dk->dk_openlock);
96 	part = DISKPART(dev);
97 
98 	/*
99 	 * If there are wedges, and this is not RAW_PART, then we
100 	 * need to fail.
101 	 */
102 	if (dk->dk_nwedges != 0 && part != RAW_PART) {
103 		ret = EBUSY;
104 		goto done;
105 	}
106 
107 	pmask = 1 << part;
108 
109 	/*
110 	 * If we're init'ed and there are no other open partitions then
111 	 * update the in-core disklabel.
112 	 */
113 	if ((dksc->sc_flags & DKF_INITED)) {
114 		if (dk->dk_openmask == 0) {
115 			dk_getdisklabel(di, dksc, dev);
116 		}
117 		/* XXX re-discover wedges? */
118 	}
119 
120 	/* Fail if we can't find the partition. */
121 	if ((part != RAW_PART) &&
122 	    (((dksc->sc_flags & DKF_INITED) == 0) ||
123 	    ((part >= lp->d_npartitions) ||
124 	    (lp->d_partitions[part].p_fstype == FS_UNUSED)))) {
125 		ret = ENXIO;
126 		goto done;
127 	}
128 
129 	/* Mark our unit as open. */
130 	switch (fmt) {
131 	case S_IFCHR:
132 		dk->dk_copenmask |= pmask;
133 		break;
134 	case S_IFBLK:
135 		dk->dk_bopenmask |= pmask;
136 		break;
137 	}
138 
139 	dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
140 
141 done:
142 	mutex_exit(&dk->dk_openlock);
143 	return ret;
144 }
145 
146 /* ARGSUSED */
147 int
148 dk_close(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
149     int flags, int fmt, struct lwp *l)
150 {
151 	int	part = DISKPART(dev);
152 	int	pmask = 1 << part;
153 	struct disk *dk = &dksc->sc_dkdev;
154 
155 	DPRINTF_FOLLOW(("dk_close(%s, %p, 0x%"PRIx64", 0x%x)\n",
156 	    di->di_dkname, dksc, dev, flags));
157 
158 	mutex_enter(&dk->dk_openlock);
159 
160 	switch (fmt) {
161 	case S_IFCHR:
162 		dk->dk_copenmask &= ~pmask;
163 		break;
164 	case S_IFBLK:
165 		dk->dk_bopenmask &= ~pmask;
166 		break;
167 	}
168 	dk->dk_openmask = dk->dk_copenmask | dk->dk_bopenmask;
169 
170 	mutex_exit(&dk->dk_openlock);
171 	return 0;
172 }
173 
174 void
175 dk_strategy(struct dk_intf *di, struct dk_softc *dksc, struct buf *bp)
176 {
177 	int	s;
178 	int	wlabel;
179 	daddr_t	blkno;
180 
181 	DPRINTF_FOLLOW(("dk_strategy(%s, %p, %p)\n",
182 	    di->di_dkname, dksc, bp));
183 
184 	if (!(dksc->sc_flags & DKF_INITED)) {
185 		DPRINTF_FOLLOW(("dk_strategy: not inited\n"));
186 		bp->b_error  = ENXIO;
187 		biodone(bp);
188 		return;
189 	}
190 
191 	/* XXX look for some more errors, c.f. ld.c */
192 
193 	bp->b_resid = bp->b_bcount;
194 
195 	/* If there is nothing to do, then we are done */
196 	if (bp->b_bcount == 0) {
197 		biodone(bp);
198 		return;
199 	}
200 
201 	wlabel = dksc->sc_flags & (DKF_WLABEL|DKF_LABELLING);
202 	if (DISKPART(bp->b_dev) != RAW_PART &&
203 	    bounds_check_with_label(&dksc->sc_dkdev, bp, wlabel) <= 0) {
204 		biodone(bp);
205 		return;
206 	}
207 
208 	blkno = bp->b_blkno;
209 	if (DISKPART(bp->b_dev) != RAW_PART) {
210 		struct partition *pp;
211 
212 		pp =
213 		    &dksc->sc_dkdev.dk_label->d_partitions[DISKPART(bp->b_dev)];
214 		blkno += pp->p_offset;
215 	}
216 	bp->b_rawblkno = blkno;
217 
218 	/*
219 	 * Start the unit by calling the start routine
220 	 * provided by the individual driver.
221 	 */
222 	s = splbio();
223 	bufq_put(dksc->sc_bufq, bp);
224 	dk_start(di, dksc);
225 	splx(s);
226 	return;
227 }
228 
229 void
230 dk_start(struct dk_intf *di, struct dk_softc *dksc)
231 {
232 	struct	buf *bp;
233 
234 	DPRINTF_FOLLOW(("dk_start(%s, %p)\n", di->di_dkname, dksc));
235 
236 	/* Process the work queue */
237 	while ((bp = bufq_get(dksc->sc_bufq)) != NULL) {
238 		if (di->di_diskstart(dksc, bp) != 0) {
239 			bufq_put(dksc->sc_bufq, bp);
240 			break;
241 		}
242 	}
243 }
244 
245 void
246 dk_iodone(struct dk_intf *di, struct dk_softc *dksc)
247 {
248 
249 	DPRINTF_FOLLOW(("dk_iodone(%s, %p)\n", di->di_dkname, dksc));
250 
251 	/* We kick the queue in case we are able to get more work done */
252 	dk_start(di, dksc);
253 }
254 
255 int
256 dk_size(struct dk_intf *di, struct dk_softc *dksc, dev_t dev)
257 {
258 	struct	disklabel *lp;
259 	int	is_open;
260 	int	part;
261 	int	size;
262 
263 	if ((dksc->sc_flags & DKF_INITED) == 0)
264 		return -1;
265 
266 	part = DISKPART(dev);
267 	is_open = dksc->sc_dkdev.dk_openmask & (1 << part);
268 
269 	if (!is_open && di->di_open(dev, 0, S_IFBLK, curlwp))
270 		return -1;
271 
272 	lp = dksc->sc_dkdev.dk_label;
273 	if (lp->d_partitions[part].p_fstype != FS_SWAP)
274 		size = -1;
275 	else
276 		size = lp->d_partitions[part].p_size *
277 		    (lp->d_secsize / DEV_BSIZE);
278 
279 	if (!is_open && di->di_close(dev, 0, S_IFBLK, curlwp))
280 		return 1;
281 
282 	return size;
283 }
284 
285 int
286 dk_ioctl(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
287 	    u_long cmd, void *data, int flag, struct lwp *l)
288 {
289 	struct	disklabel *lp;
290 	struct	disk *dk;
291 #ifdef __HAVE_OLD_DISKLABEL
292 	struct	disklabel newlabel;
293 #endif
294 	int	error = 0;
295 
296 	DPRINTF_FOLLOW(("dk_ioctl(%s, %p, 0x%"PRIx64", 0x%lx)\n",
297 	    di->di_dkname, dksc, dev, cmd));
298 
299 	/* ensure that the pseudo disk is open for writes for these commands */
300 	switch (cmd) {
301 	case DIOCSDINFO:
302 	case DIOCWDINFO:
303 #ifdef __HAVE_OLD_DISKLABEL
304 	case ODIOCSDINFO:
305 	case ODIOCWDINFO:
306 #endif
307 	case DIOCWLABEL:
308 	case DIOCAWEDGE:
309 	case DIOCDWEDGE:
310 		if ((flag & FWRITE) == 0)
311 			return EBADF;
312 	}
313 
314 	/* ensure that the pseudo-disk is initialized for these */
315 	switch (cmd) {
316 #ifdef DIOCGSECTORSIZE
317 	case DIOCGSECTORSIZE:
318 	case DIOCGMEDIASIZE:
319 #endif
320 	case DIOCGDINFO:
321 	case DIOCSDINFO:
322 	case DIOCWDINFO:
323 	case DIOCGPART:
324 	case DIOCWLABEL:
325 	case DIOCGDEFLABEL:
326 	case DIOCAWEDGE:
327 	case DIOCDWEDGE:
328 	case DIOCLWEDGES:
329 	case DIOCCACHESYNC:
330 #ifdef __HAVE_OLD_DISKLABEL
331 	case ODIOCGDINFO:
332 	case ODIOCSDINFO:
333 	case ODIOCWDINFO:
334 	case ODIOCGDEFLABEL:
335 #endif
336 		if ((dksc->sc_flags & DKF_INITED) == 0)
337 			return ENXIO;
338 	}
339 
340 	switch (cmd) {
341 #ifdef DIOCGSECTORSIZE
342 	case DIOCGSECTORSIZE:
343 		*(u_int *)data = dksc->sc_dkdev.dk_geom.dg_secsize;
344 		return 0;
345 	case DIOCGMEDIASIZE:
346 		*(off_t *)data =
347 		    (off_t)dksc->sc_dkdev.dk_geom.dg_secsize *
348 		    dksc->sc_dkdev.dk_geom.dg_nsectors;
349 		return 0;
350 #endif
351 
352 	case DIOCGDINFO:
353 		*(struct disklabel *)data = *(dksc->sc_dkdev.dk_label);
354 		break;
355 
356 #ifdef __HAVE_OLD_DISKLABEL
357 	case ODIOCGDINFO:
358 		newlabel = *(dksc->sc_dkdev.dk_label);
359 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
360 			return ENOTTY;
361 		memcpy(data, &newlabel, sizeof (struct olddisklabel));
362 		break;
363 #endif
364 
365 	case DIOCGPART:
366 		((struct partinfo *)data)->disklab = dksc->sc_dkdev.dk_label;
367 		((struct partinfo *)data)->part =
368 		    &dksc->sc_dkdev.dk_label->d_partitions[DISKPART(dev)];
369 		break;
370 
371 	case DIOCWDINFO:
372 	case DIOCSDINFO:
373 #ifdef __HAVE_OLD_DISKLABEL
374 	case ODIOCWDINFO:
375 	case ODIOCSDINFO:
376 #endif
377 #ifdef __HAVE_OLD_DISKLABEL
378 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
379 			memset(&newlabel, 0, sizeof newlabel);
380 			memcpy(&newlabel, data, sizeof (struct olddisklabel));
381 			lp = &newlabel;
382 		} else
383 #endif
384 		lp = (struct disklabel *)data;
385 
386 		dk = &dksc->sc_dkdev;
387 		mutex_enter(&dk->dk_openlock);
388 		dksc->sc_flags |= DKF_LABELLING;
389 
390 		error = setdisklabel(dksc->sc_dkdev.dk_label,
391 		    lp, 0, dksc->sc_dkdev.dk_cpulabel);
392 		if (error == 0) {
393 			if (cmd == DIOCWDINFO
394 #ifdef __HAVE_OLD_DISKLABEL
395 			    || cmd == ODIOCWDINFO
396 #endif
397 			   )
398 				error = writedisklabel(DKLABELDEV(dev),
399 				    di->di_strategy, dksc->sc_dkdev.dk_label,
400 				    dksc->sc_dkdev.dk_cpulabel);
401 		}
402 
403 		dksc->sc_flags &= ~DKF_LABELLING;
404 		mutex_exit(&dk->dk_openlock);
405 		break;
406 
407 	case DIOCWLABEL:
408 		if (*(int *)data != 0)
409 			dksc->sc_flags |= DKF_WLABEL;
410 		else
411 			dksc->sc_flags &= ~DKF_WLABEL;
412 		break;
413 
414 	case DIOCGDEFLABEL:
415 		dk_getdefaultlabel(di, dksc, (struct disklabel *)data);
416 		break;
417 
418 #ifdef __HAVE_OLD_DISKLABEL
419 	case ODIOCGDEFLABEL:
420 		dk_getdefaultlabel(di, dksc, &newlabel);
421 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
422 			return ENOTTY;
423 		memcpy(data, &newlabel, sizeof (struct olddisklabel));
424 		break;
425 #endif
426 
427 	case DIOCAWEDGE:
428 	    {
429 	    	struct dkwedge_info *dkw = (void *)data;
430 
431 		if ((flag & FWRITE) == 0)
432 			return (EBADF);
433 
434 		/* If the ioctl happens here, the parent is us. */
435 		strcpy(dkw->dkw_parent, dksc->sc_dkdev.dk_name);
436 		return (dkwedge_add(dkw));
437 	    }
438 
439 	case DIOCDWEDGE:
440 	    {
441 	    	struct dkwedge_info *dkw = (void *)data;
442 
443 		if ((flag & FWRITE) == 0)
444 			return (EBADF);
445 
446 		/* If the ioctl happens here, the parent is us. */
447 		strcpy(dkw->dkw_parent, dksc->sc_dkdev.dk_name);
448 		return (dkwedge_del(dkw));
449 	    }
450 
451 	case DIOCLWEDGES:
452 	    {
453 	    	struct dkwedge_list *dkwl = (void *)data;
454 
455 		return (dkwedge_list(&dksc->sc_dkdev, dkwl, l));
456 	    }
457 
458 	case DIOCGSTRATEGY:
459 	    {
460 		struct disk_strategy *dks = (void *)data;
461 		int s;
462 
463 		s = splbio();
464 		strlcpy(dks->dks_name, bufq_getstrategyname(dksc->sc_bufq),
465 		    sizeof(dks->dks_name));
466 		splx(s);
467 		dks->dks_paramlen = 0;
468 
469 		return 0;
470 	    }
471 
472 	case DIOCSSTRATEGY:
473 	    {
474 		struct disk_strategy *dks = (void *)data;
475 		struct bufq_state *new;
476 		struct bufq_state *old;
477 		int s;
478 
479 		if ((flag & FWRITE) == 0) {
480 			return EBADF;
481 		}
482 		if (dks->dks_param != NULL) {
483 			return EINVAL;
484 		}
485 		dks->dks_name[sizeof(dks->dks_name) - 1] = 0; /* ensure term */
486 		error = bufq_alloc(&new, dks->dks_name,
487 		    BUFQ_EXACT|BUFQ_SORT_RAWBLOCK);
488 		if (error) {
489 			return error;
490 		}
491 		s = splbio();
492 		old = dksc->sc_bufq;
493 		bufq_move(new, old);
494 		dksc->sc_bufq = new;
495 		splx(s);
496 		bufq_free(old);
497 
498 		return 0;
499 	    }
500 
501 	default:
502 		error = ENOTTY;
503 	}
504 
505 	return error;
506 }
507 
508 /*
509  * dk_dump dumps all of physical memory into the partition specified.
510  * This requires substantially more framework than {s,w}ddump, and hence
511  * is probably much more fragile.
512  *
513  * XXX: we currently do not implement this.
514  */
515 
516 #define DKF_READYFORDUMP	(DKF_INITED|DKF_TAKEDUMP)
517 #define DKFF_READYFORDUMP(x)	(((x) & DKF_READYFORDUMP) == DKF_READYFORDUMP)
518 static volatile int	dk_dumping = 0;
519 
520 /* ARGSUSED */
521 int
522 dk_dump(struct dk_intf *di, struct dk_softc *dksc, dev_t dev,
523     daddr_t blkno, void *va, size_t size)
524 {
525 
526 	/*
527 	 * ensure that we consider this device to be safe for dumping,
528 	 * and that the device is configured.
529 	 */
530 	if (!DKFF_READYFORDUMP(dksc->sc_flags))
531 		return ENXIO;
532 
533 	/* ensure that we are not already dumping */
534 	if (dk_dumping)
535 		return EFAULT;
536 	dk_dumping = 1;
537 
538 	/* XXX: unimplemented */
539 
540 	dk_dumping = 0;
541 
542 	/* XXX: actually for now, we are going to leave this alone */
543 	return ENXIO;
544 }
545 
546 /* ARGSUSED */
547 void
548 dk_getdefaultlabel(struct dk_intf *di, struct dk_softc *dksc,
549 		      struct disklabel *lp)
550 {
551 	struct disk_geom *dg = &dksc->sc_dkdev.dk_geom;
552 
553 	memset(lp, 0, sizeof(*lp));
554 
555 	lp->d_secperunit = dg->dg_secperunit;
556 	lp->d_secsize = dg->dg_secsize;
557 	lp->d_nsectors = dg->dg_nsectors;
558 	lp->d_ntracks = dg->dg_ntracks;
559 	lp->d_ncylinders = dg->dg_ncylinders;
560 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
561 
562 	strncpy(lp->d_typename, di->di_dkname, sizeof(lp->d_typename));
563 	lp->d_type = di->di_dtype;
564 	strncpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
565 	lp->d_rpm = 3600;
566 	lp->d_interleave = 1;
567 	lp->d_flags = 0;
568 
569 	lp->d_partitions[RAW_PART].p_offset = 0;
570 	lp->d_partitions[RAW_PART].p_size = dg->dg_secperunit;
571 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
572 	lp->d_npartitions = RAW_PART + 1;
573 
574 	lp->d_magic = DISKMAGIC;
575 	lp->d_magic2 = DISKMAGIC;
576 	lp->d_checksum = dkcksum(dksc->sc_dkdev.dk_label);
577 }
578 
579 /* ARGSUSED */
580 void
581 dk_getdisklabel(struct dk_intf *di, struct dk_softc *dksc, dev_t dev)
582 {
583 	struct	 disklabel *lp = dksc->sc_dkdev.dk_label;
584 	struct	 cpu_disklabel *clp = dksc->sc_dkdev.dk_cpulabel;
585 	struct disk_geom *dg = &dksc->sc_dkdev.dk_geom;
586 	struct	 partition *pp;
587 	int	 i;
588 	const char	*errstring;
589 
590 	memset(clp, 0x0, sizeof(*clp));
591 	dk_getdefaultlabel(di, dksc, lp);
592 	errstring = readdisklabel(DKLABELDEV(dev), di->di_strategy,
593 	    dksc->sc_dkdev.dk_label, dksc->sc_dkdev.dk_cpulabel);
594 	if (errstring) {
595 		dk_makedisklabel(di, dksc);
596 		if (dksc->sc_flags & DKF_WARNLABEL)
597 			printf("%s: %s\n", dksc->sc_xname, errstring);
598 		return;
599 	}
600 
601 	if ((dksc->sc_flags & DKF_LABELSANITY) == 0)
602 		return;
603 
604 	/* Sanity check */
605 	if (lp->d_secperunit != dg->dg_secperunit)
606 		printf("WARNING: %s: total sector size in disklabel (%d) "
607 		    "!= the size of %s (%" PRId64 ")\n", dksc->sc_xname,
608 		    lp->d_secperunit, di->di_dkname, dg->dg_secperunit);
609 
610 	for (i=0; i < lp->d_npartitions; i++) {
611 		pp = &lp->d_partitions[i];
612 		if (pp->p_offset + pp->p_size > dg->dg_secperunit)
613 			printf("WARNING: %s: end of partition `%c' exceeds "
614 			    "the size of %s (%" PRId64 ")\n", dksc->sc_xname,
615 			    'a' + i, di->di_dkname, dg->dg_secperunit);
616 	}
617 }
618 
619 /* ARGSUSED */
620 static void
621 dk_makedisklabel(struct dk_intf *di, struct dk_softc *dksc)
622 {
623 	struct	disklabel *lp = dksc->sc_dkdev.dk_label;
624 
625 	lp->d_partitions[RAW_PART].p_fstype = FS_BSDFFS;
626 	strncpy(lp->d_packname, "default label", sizeof(lp->d_packname));
627 	lp->d_checksum = dkcksum(lp);
628 }
629 
630 /* This function is taken from ccd.c:1.76  --rcd */
631 
632 /*
633  * XXX this function looks too generic for dksubr.c, shouldn't we
634  *     put it somewhere better?
635  */
636 
637 /*
638  * Lookup the provided name in the filesystem.  If the file exists,
639  * is a valid block device, and isn't being used by anyone else,
640  * set *vpp to the file's vnode.
641  */
642 int
643 dk_lookup(struct pathbuf *pb, struct lwp *l, struct vnode **vpp)
644 {
645 	struct nameidata nd;
646 	struct vnode *vp;
647 	struct vattr va;
648 	int     error;
649 
650 	if (l == NULL)
651 		return ESRCH;	/* Is ESRCH the best choice? */
652 
653 	NDINIT(&nd, LOOKUP, FOLLOW, pb);
654 	if ((error = vn_open(&nd, FREAD | FWRITE, 0)) != 0) {
655 		DPRINTF((DKDB_FOLLOW|DKDB_INIT),
656 		    ("dk_lookup: vn_open error = %d\n", error));
657 		return error;
658 	}
659 
660 	vp = nd.ni_vp;
661 	if ((error = VOP_GETATTR(vp, &va, l->l_cred)) != 0) {
662 		DPRINTF((DKDB_FOLLOW|DKDB_INIT),
663 		    ("dk_lookup: getattr error = %d\n", error));
664 		goto out;
665 	}
666 
667 	/* XXX: eventually we should handle VREG, too. */
668 	if (va.va_type != VBLK) {
669 		error = ENOTBLK;
670 		goto out;
671 	}
672 
673 	IFDEBUG(DKDB_VNODE, vprint("dk_lookup: vnode info", vp));
674 
675 	VOP_UNLOCK(vp);
676 	*vpp = vp;
677 	return 0;
678 out:
679 	VOP_UNLOCK(vp);
680 	(void) vn_close(vp, FREAD | FWRITE, l->l_cred);
681 	return error;
682 }
683