xref: /netbsd-src/sys/kern/kern_subr.c (revision bada23909e740596d0a3785a73bd3583a9807fb8)
1 /*	$NetBSD: kern_subr.c,v 1.44 1999/02/10 17:03:28 kleink Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998 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 of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the NetBSD
22  *	Foundation, Inc. and its contributors.
23  * 4. Neither the name of The NetBSD Foundation nor the names of its
24  *    contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /*
41  * Copyright (c) 1982, 1986, 1991, 1993
42  *	The Regents of the University of California.  All rights reserved.
43  * (c) UNIX System Laboratories, Inc.
44  * All or some portions of this file are derived from material licensed
45  * to the University of California by American Telephone and Telegraph
46  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
47  * the permission of UNIX System Laboratories, Inc.
48  *
49  * Copyright (c) 1992, 1993
50  *	The Regents of the University of California.  All rights reserved.
51  *
52  * This software was developed by the Computer Systems Engineering group
53  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
54  * contributed to Berkeley.
55  *
56  * All advertising materials mentioning features or use of this software
57  * must display the following acknowledgement:
58  *	This product includes software developed by the University of
59  *	California, Lawrence Berkeley Laboratory.
60  *
61  * Redistribution and use in source and binary forms, with or without
62  * modification, are permitted provided that the following conditions
63  * are met:
64  * 1. Redistributions of source code must retain the above copyright
65  *    notice, this list of conditions and the following disclaimer.
66  * 2. Redistributions in binary form must reproduce the above copyright
67  *    notice, this list of conditions and the following disclaimer in the
68  *    documentation and/or other materials provided with the distribution.
69  * 3. All advertising materials mentioning features or use of this software
70  *    must display the following acknowledgement:
71  *	This product includes software developed by the University of
72  *	California, Berkeley and its contributors.
73  * 4. Neither the name of the University nor the names of its contributors
74  *    may be used to endorse or promote products derived from this software
75  *    without specific prior written permission.
76  *
77  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
78  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
79  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
80  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
81  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
82  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
83  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
84  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
85  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
86  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
87  * SUCH DAMAGE.
88  *
89  *	@(#)kern_subr.c	8.4 (Berkeley) 2/14/95
90  */
91 
92 #include "opt_md.h"
93 #include "opt_uvm.h"
94 
95 #include <sys/param.h>
96 #include <sys/systm.h>
97 #include <sys/proc.h>
98 #include <sys/malloc.h>
99 #include <sys/mount.h>
100 #include <sys/device.h>
101 #include <sys/reboot.h>
102 #include <sys/conf.h>
103 #include <sys/disklabel.h>
104 #include <sys/queue.h>
105 
106 #include <dev/cons.h>
107 
108 #include <net/if.h>
109 
110 /* XXX these should eventually move to subr_autoconf.c */
111 static int findblkmajor __P((const char *, struct devnametobdevmaj *));
112 static const char *findblkname __P((int, struct devnametobdevmaj *));
113 static struct device *getdisk __P((char *, int, int,
114 	struct devnametobdevmaj *, dev_t *, int));
115 static struct device *parsedisk __P((char *, int, int,
116 	struct devnametobdevmaj *, dev_t *));
117 static int getstr __P((char *, int));
118 
119 int
120 uiomove(buf, n, uio)
121 	register void *buf;
122 	register int n;
123 	register struct uio *uio;
124 {
125 	register struct iovec *iov;
126 	u_int cnt;
127 	int error = 0;
128 	char *cp = buf;
129 
130 #ifdef DIAGNOSTIC
131 	if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
132 		panic("uiomove: mode");
133 	if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
134 		panic("uiomove proc");
135 #endif
136 	while (n > 0 && uio->uio_resid) {
137 		iov = uio->uio_iov;
138 		cnt = iov->iov_len;
139 		if (cnt == 0) {
140 			uio->uio_iov++;
141 			uio->uio_iovcnt--;
142 			continue;
143 		}
144 		if (cnt > n)
145 			cnt = n;
146 		switch (uio->uio_segflg) {
147 
148 		case UIO_USERSPACE:
149 			if (uio->uio_rw == UIO_READ)
150 				error = copyout(cp, iov->iov_base, cnt);
151 			else
152 				error = copyin(iov->iov_base, cp, cnt);
153 			if (error)
154 				return (error);
155 			break;
156 
157 		case UIO_SYSSPACE:
158 #if defined(UVM)
159 			if (uio->uio_rw == UIO_READ)
160 				error = kcopy(cp, iov->iov_base, cnt);
161 			else
162 				error = kcopy(iov->iov_base, cp, cnt);
163 			if (error)
164 				return(error);
165 #else
166 			if (uio->uio_rw == UIO_READ)
167 				memcpy(iov->iov_base, cp, cnt);
168 			else
169 				memcpy(cp, iov->iov_base, cnt);
170 #endif
171 			break;
172 		}
173 		iov->iov_base = (caddr_t)iov->iov_base + cnt;
174 		iov->iov_len -= cnt;
175 		uio->uio_resid -= cnt;
176 		uio->uio_offset += cnt;
177 		cp += cnt;
178 		n -= cnt;
179 	}
180 	return (error);
181 }
182 
183 /*
184  * Give next character to user as result of read.
185  */
186 int
187 ureadc(c, uio)
188 	register int c;
189 	register struct uio *uio;
190 {
191 	register struct iovec *iov;
192 
193 	if (uio->uio_resid <= 0)
194 		panic("ureadc: non-positive resid");
195 again:
196 	if (uio->uio_iovcnt <= 0)
197 		panic("ureadc: non-positive iovcnt");
198 	iov = uio->uio_iov;
199 	if (iov->iov_len <= 0) {
200 		uio->uio_iovcnt--;
201 		uio->uio_iov++;
202 		goto again;
203 	}
204 	switch (uio->uio_segflg) {
205 
206 	case UIO_USERSPACE:
207 		if (subyte(iov->iov_base, c) < 0)
208 			return (EFAULT);
209 		break;
210 
211 	case UIO_SYSSPACE:
212 		*(char *)iov->iov_base = c;
213 		break;
214 	}
215 	iov->iov_base = (caddr_t)iov->iov_base + 1;
216 	iov->iov_len--;
217 	uio->uio_resid--;
218 	uio->uio_offset++;
219 	return (0);
220 }
221 
222 /*
223  * General routine to allocate a hash table.
224  * Allocate enough memory to hold at least `elements' list-head pointers.
225  * Return a pointer to the allocated space and set *hashmask to a pattern
226  * suitable for masking a value to use as an index into the returned array.
227  */
228 void *
229 hashinit(elements, type, flags, hashmask)
230 	int elements, type, flags;
231 	u_long *hashmask;
232 {
233 	long hashsize;
234 	LIST_HEAD(generic, generic) *hashtbl;
235 	int i;
236 
237 	if (elements <= 0)
238 		panic("hashinit: bad cnt");
239 	for (hashsize = 1; hashsize < elements; hashsize <<= 1)
240 		continue;
241 	hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, flags);
242 	for (i = 0; i < hashsize; i++)
243 		LIST_INIT(&hashtbl[i]);
244 	*hashmask = hashsize - 1;
245 	return (hashtbl);
246 }
247 
248 /*
249  * "Shutdown hook" types, functions, and variables.
250  */
251 
252 struct shutdownhook_desc {
253 	LIST_ENTRY(shutdownhook_desc) sfd_list;
254 	void	(*sfd_fn) __P((void *));
255 	void	*sfd_arg;
256 };
257 
258 LIST_HEAD(, shutdownhook_desc) shutdownhook_list;
259 
260 void *
261 shutdownhook_establish(fn, arg)
262 	void (*fn) __P((void *));
263 	void *arg;
264 {
265 	struct shutdownhook_desc *ndp;
266 
267 	ndp = (struct shutdownhook_desc *)
268 	    malloc(sizeof(*ndp), M_DEVBUF, M_NOWAIT);
269 	if (ndp == NULL)
270 		return NULL;
271 
272 	ndp->sfd_fn = fn;
273 	ndp->sfd_arg = arg;
274 	LIST_INSERT_HEAD(&shutdownhook_list, ndp, sfd_list);
275 
276 	return (ndp);
277 }
278 
279 void
280 shutdownhook_disestablish(vhook)
281 	void *vhook;
282 {
283 #ifdef DIAGNOSTIC
284 	struct shutdownhook_desc *dp;
285 
286 	for (dp = shutdownhook_list.lh_first; dp != NULL;
287 	    dp = dp->sfd_list.le_next)
288                 if (dp == vhook)
289 			break;
290 	if (dp == NULL)
291 		panic("shutdownhook_disestablish: hook not established");
292 #endif
293 
294 	LIST_REMOVE((struct shutdownhook_desc *)vhook, sfd_list);
295 	free(vhook, M_DEVBUF);
296 }
297 
298 /*
299  * Run shutdown hooks.  Should be invoked immediately before the
300  * system is halted or rebooted, i.e. after file systems unmounted,
301  * after crash dump done, etc.
302  *
303  * Each shutdown hook is removed from the list before it's run, so that
304  * it won't be run again.
305  */
306 void
307 doshutdownhooks()
308 {
309 	struct shutdownhook_desc *dp;
310 
311 	while ((dp = shutdownhook_list.lh_first) != NULL) {
312 		LIST_REMOVE(dp, sfd_list);
313 		(*dp->sfd_fn)(dp->sfd_arg);
314 #if 0
315 		/*
316 		 * Don't bother freeing the hook structure,, since we may
317 		 * be rebooting because of a memory corruption problem,
318 		 * and this might only make things worse.  It doesn't
319 		 * matter, anyway, since the system is just about to
320 		 * reboot.
321 		 */
322 		free(dp, M_DEVBUF);
323 #endif
324 	}
325 }
326 
327 /*
328  * "Mountroot hook" types, functions, and variables.
329  */
330 
331 struct mountroothook_desc {
332 	LIST_ENTRY(mountroothook_desc) mrd_list;
333 	struct	device *mrd_device;
334 	void 	(*mrd_func) __P((struct device *));
335 };
336 
337 LIST_HEAD(, mountroothook_desc) mountroothook_list;
338 
339 void *
340 mountroothook_establish(func, dev)
341 	void (*func) __P((struct device *));
342 	struct device *dev;
343 {
344 	struct mountroothook_desc *mrd;
345 
346 	mrd = (struct mountroothook_desc *)
347 	    malloc(sizeof(*mrd), M_DEVBUF, M_NOWAIT);
348 	if (mrd == NULL)
349 		return (NULL);
350 
351 	mrd->mrd_device = dev;
352 	mrd->mrd_func = func;
353 	LIST_INSERT_HEAD(&mountroothook_list, mrd, mrd_list);
354 
355 	return (mrd);
356 }
357 
358 void
359 mountroothook_disestablish(vhook)
360 	void *vhook;
361 {
362 #ifdef DIAGNOSTIC
363 	struct mountroothook_desc *mrd;
364 
365 	for (mrd = mountroothook_list.lh_first; mrd != NULL;
366 	    mrd = mrd->mrd_list.le_next)
367                 if (mrd == vhook)
368 			break;
369 	if (mrd == NULL)
370 		panic("mountroothook_disestablish: hook not established");
371 #endif
372 
373 	LIST_REMOVE((struct mountroothook_desc *)vhook, mrd_list);
374 	free(vhook, M_DEVBUF);
375 }
376 
377 void
378 mountroothook_destroy()
379 {
380 	struct mountroothook_desc *mrd;
381 
382 	while ((mrd = mountroothook_list.lh_first) != NULL) {
383 		LIST_REMOVE(mrd, mrd_list);
384 		free(mrd, M_DEVBUF);
385 	}
386 }
387 
388 void
389 domountroothook()
390 {
391 	struct mountroothook_desc *mrd;
392 
393 	for (mrd = mountroothook_list.lh_first; mrd != NULL;
394 	    mrd = mrd->mrd_list.le_next) {
395 		if (mrd->mrd_device == root_device) {
396 			(*mrd->mrd_func)(root_device);
397 			return;
398 		}
399 	}
400 }
401 
402 /*
403  * Determine the root device and, if instructed to, the root file system.
404  */
405 
406 #include "md.h"
407 #if NMD == 0
408 #undef MEMORY_DISK_HOOKS
409 #endif
410 
411 #ifdef MEMORY_DISK_HOOKS
412 static struct device fakemdrootdev[NMD];
413 #endif
414 
415 void
416 setroot(bootdv, bootpartition, nam2blk)
417 	struct device *bootdv;
418 	int bootpartition;
419 	struct devnametobdevmaj *nam2blk;
420 {
421 	struct device *dv;
422 	int len, print_newline = 0;
423 #ifdef MEMORY_DISK_HOOKS
424 	int i;
425 #endif
426 	dev_t nrootdev;
427 	dev_t ndumpdev = NODEV;
428 	char buf[128];
429 	const char *rootdevname;
430 	const char *dumpdevname;
431 	struct device *rootdv = NULL;		/* XXX gcc -Wuninitialized */
432 	struct device *dumpdv = NULL;
433 	struct ifnet *ifp;
434 	const char *deffsname;
435 	struct vfsops *vops;
436 	extern int (*mountroot) __P((void));
437 	static struct devnametobdevmaj *last_nam2blk;
438 
439 	if (nam2blk == NULL) {
440 		if (last_nam2blk == NULL)
441 			panic("setroot: no name to bdev major map");
442 		nam2blk = last_nam2blk;
443 	}
444 	last_nam2blk = nam2blk;
445 
446 #ifdef MEMORY_DISK_HOOKS
447 	for (i = 0; i < NMD; i++) {
448 		fakemdrootdev[i].dv_class  = DV_DISK;
449 		fakemdrootdev[i].dv_cfdata = NULL;
450 		fakemdrootdev[i].dv_unit   = i;
451 		fakemdrootdev[i].dv_parent = NULL;
452 		sprintf(fakemdrootdev[i].dv_xname, "md%d", i);
453 	}
454 #endif /* MEMORY_DISK_HOOKS */
455 
456 #ifdef MEMORY_DISK_IS_ROOT
457 	bootdv = &fakemdrootdev[0];
458 	bootpartition = 0;
459 #endif
460 
461 	/*
462 	 * If NFS is specified as the file system, and we found
463 	 * a DV_DISK boot device (or no boot device at all), then
464 	 * find a reasonable network interface for "rootspec".
465 	 */
466 	vops = vfs_getopsbyname("nfs");
467 	if (vops != NULL && vops->vfs_mountroot == mountroot &&
468 	    rootspec == NULL &&
469 	    (bootdv == NULL || bootdv->dv_class != DV_IFNET)) {
470 		for (ifp = ifnet.tqh_first; ifp != NULL;
471 		    ifp = ifp->if_list.tqe_next)
472 			if ((ifp->if_flags &
473 			     (IFF_LOOPBACK|IFF_POINTOPOINT)) == 0)
474 				break;
475 		if (ifp == NULL) {
476 			/*
477 			 * Can't find a suitable interface; ask the
478 			 * user.
479 			 */
480 			boothowto |= RB_ASKNAME;
481 		} else {
482 			/*
483 			 * Have a suitable interface; behave as if
484 			 * the user specified this interface.
485 			 */
486 			rootspec = (const char *)ifp->if_xname;
487 		}
488 	}
489 
490 	/*
491 	 * If wildcarded root and we the boot device wasn't determined,
492 	 * ask the user.
493 	 */
494 	if (rootspec == NULL && bootdv == NULL)
495 		boothowto |= RB_ASKNAME;
496 
497  top:
498 	if (boothowto & RB_ASKNAME) {
499 		struct device *defdumpdv;
500 
501 		for (;;) {
502 			printf("root device");
503 			if (bootdv != NULL) {
504 				printf(" (default %s", bootdv->dv_xname);
505 				if (bootdv->dv_class == DV_DISK)
506 					printf("%c", bootpartition + 'a');
507 				printf(")");
508 			}
509 			printf(": ");
510 			len = getstr(buf, sizeof(buf));
511 			if (len == 0 && bootdv != NULL) {
512 				strcpy(buf, bootdv->dv_xname);
513 				len = strlen(buf);
514 			}
515 			if (len > 0 && buf[len - 1] == '*') {
516 				buf[--len] = '\0';
517 				dv = getdisk(buf, len, 1, nam2blk,
518 				    &nrootdev, 0);
519 				if (dv != NULL) {
520 					rootdv = dv;
521 					break;
522 				}
523 			}
524 			dv = getdisk(buf, len, bootpartition, nam2blk,
525 			    &nrootdev, 0);
526 			if (dv != NULL) {
527 				rootdv = dv;
528 				break;
529 			}
530 		}
531 
532 		/*
533 		 * Set up the default dump device.  If root is on
534 		 * a network device, there is no default dump
535 		 * device, since we don't support dumps to the
536 		 * network.
537 		 */
538 		if (rootdv->dv_class == DV_IFNET)
539 			defdumpdv = NULL;
540 		else
541 			defdumpdv = rootdv;
542 
543 		for (;;) {
544 			printf("dump device");
545 			if (defdumpdv != NULL) {
546 				/*
547 				 * Note, we know it's a disk if we get here.
548 				 */
549 				printf(" (default %sb)", defdumpdv->dv_xname);
550 			}
551 			printf(": ");
552 			len = getstr(buf, sizeof(buf));
553 			if (len == 0) {
554 				if (defdumpdv != NULL) {
555 					ndumpdev = MAKEDISKDEV(major(nrootdev),
556 					    DISKUNIT(nrootdev), 1);
557 				}
558 				if (rootdv->dv_class == DV_IFNET)
559 					dumpdv = NULL;
560 				else
561 					dumpdv = rootdv;
562 				break;
563 			}
564 			if (len == 4 && strcmp(buf, "none") == 0) {
565 				dumpspec = "none";
566 				goto havedump;
567 			}
568 			dv = getdisk(buf, len, 1, nam2blk, &ndumpdev, 1);
569 			if (dv) {
570 				dumpdv = dv;
571 				break;
572 			}
573 		}
574 
575  havedump:
576 		rootdev = nrootdev;
577 		dumpdev = ndumpdev;
578 
579 		for (vops = LIST_FIRST(&vfs_list); vops != NULL;
580 		     vops = LIST_NEXT(vops, vfs_list)) {
581 			if (vops->vfs_mountroot != NULL &&
582 			    vops->vfs_mountroot == mountroot)
583 			break;
584 		}
585 
586 		if (vops == NULL) {
587 			mountroot = NULL;
588 			deffsname = "generic";
589 		} else
590 			deffsname = vops->vfs_name;
591 
592 		for (;;) {
593 			printf("file system (default %s): ", deffsname);
594 			len = getstr(buf, sizeof(buf));
595 			if (len == 0)
596 				break;
597 			if (len == 4 && strcmp(buf, "halt") == 0)
598 				cpu_reboot(RB_HALT, NULL);
599 			else if (len == 7 && strcmp(buf, "generic") == 0) {
600 				mountroot = NULL;
601 				break;
602 			}
603 			vops = vfs_getopsbyname(buf);
604 			if (vops == NULL || vops->vfs_mountroot == NULL) {
605 				printf("use one of: generic");
606 				for (vops = LIST_FIRST(&vfs_list);
607 				     vops != NULL;
608 				     vops = LIST_NEXT(vops, vfs_list)) {
609 					if (vops->vfs_mountroot != NULL)
610 						printf(" %s", vops->vfs_name);
611 				}
612 				printf(" halt\n");
613 			} else {
614 				mountroot = vops->vfs_mountroot;
615 				break;
616 			}
617 		}
618 
619 	} else if (rootspec == NULL) {
620 		int majdev;
621 
622 		/*
623 		 * Wildcarded root; use the boot device.
624 		 */
625 		rootdv = bootdv;
626 
627 		majdev = findblkmajor(bootdv->dv_xname, nam2blk);
628 		if (majdev >= 0) {
629 			/*
630 			 * Root is on a disk.  `bootpartition' is root.
631 			 */
632 			rootdev = MAKEDISKDEV(majdev, bootdv->dv_unit,
633 			    bootpartition);
634 		}
635 	} else {
636 
637 		/*
638 		 * `root on <dev> ...'
639 		 */
640 
641 		/*
642 		 * If it's a network interface, we can bail out
643 		 * early.
644 		 */
645 		for (dv = alldevs.tqh_first; dv != NULL;
646 		    dv = dv->dv_list.tqe_next)
647 			if (strcmp(dv->dv_xname, rootspec) == 0)
648 				break;
649 		if (dv != NULL && dv->dv_class == DV_IFNET) {
650 			rootdv = dv;
651 			goto haveroot;
652 		}
653 
654 		rootdevname = findblkname(major(rootdev), nam2blk);
655 		if (rootdevname == NULL) {
656 			printf("unknown device major 0x%x\n", rootdev);
657 			boothowto |= RB_ASKNAME;
658 			goto top;
659 		}
660 		memset(buf, 0, sizeof(buf));
661 		sprintf(buf, "%s%d", rootdevname, DISKUNIT(rootdev));
662 
663 		for (dv = alldevs.tqh_first; dv != NULL;
664 		    dv = dv->dv_list.tqe_next) {
665 			if (strcmp(buf, dv->dv_xname) == 0) {
666 				rootdv = dv;
667 				break;
668 			}
669 		}
670 		if (rootdv == NULL) {
671 			printf("device %s (0x%x) not configured\n",
672 			    buf, rootdev);
673 			boothowto |= RB_ASKNAME;
674 			goto top;
675 		}
676 	}
677 
678  haveroot:
679 
680 	root_device = rootdv;
681 
682 	switch (rootdv->dv_class) {
683 	case DV_IFNET:
684 		/* Nothing. */
685 		break;
686 
687 	case DV_DISK:
688 		printf("root on %s%c", rootdv->dv_xname,
689 		    DISKPART(rootdev) + 'a');
690 		print_newline = 1;
691 		break;
692 
693 	default:
694 		printf("can't determine root device\n");
695 		boothowto |= RB_ASKNAME;
696 		goto top;
697 	}
698 
699 	/*
700 	 * Now configure the dump device.
701 	 */
702 
703 	if (dumpspec != NULL && strcmp(dumpspec, "none") == 0) {
704 		/*
705 		 * Operator doesn't want a dump device.
706 		 */
707 		goto nodumpdev;
708 	}
709 
710 	/*
711 	 * If we haven't figured out the dump device, do so, with
712 	 * the following rules:
713 	 *
714 	 *	(a) We already know dumpdv in the RB_ASKNAME case.
715 	 *
716 	 *	(b) If dumpspec is set, try to use it.  If the device
717 	 *	    is not available, punt.
718 	 *
719 	 *	(c) If dumpspec is not set, the dump device is
720 	 *	    wildcarded or unspecified.  If the root device
721 	 *	    is DV_IFNET, punt.  Otherwise, use partition b
722 	 *	    of the root device.
723 	 */
724 
725 	if (boothowto & RB_ASKNAME) {
726 		if (dumpdv == NULL) {
727 			/*
728 			 * Just return; dumpdev is already set to NODEV
729 			 * and we don't want to print a newline in this
730 			 * case.
731 			 */
732 			return;
733 		}
734 		goto out;
735 	}
736 
737 	if (dumpspec != NULL) {
738 		if (dumpdev == NODEV) {
739 			/*
740 			 * Looks like they tried to pick a network
741 			 * device.  Oops.
742 			 */
743 			goto nodumpdev;
744 		}
745 
746 		dumpdevname = findblkname(major(dumpdev), nam2blk);
747 		if (dumpdevname == NULL)
748 			goto nodumpdev;
749 		memset(buf, 0, sizeof(buf));
750 		sprintf(buf, "%s%d", dumpdevname, DISKUNIT(dumpdev));
751 
752 		for (dv = alldevs.tqh_first; dv != NULL;
753 		    dv = dv->dv_list.tqe_next) {
754 			if (strcmp(buf, dv->dv_xname) == 0) {
755 				dumpdv = dv;
756 				break;
757 			}
758 		}
759 		if (dv == NULL) {
760 			/*
761 			 * Device not configured.
762 			 */
763 			goto nodumpdev;
764 		}
765 	} else if (rootdv->dv_class == DV_IFNET)
766 		goto nodumpdev;
767 	else {
768 		dumpdv = rootdv;
769 		dumpdev = MAKEDISKDEV(major(rootdev), dumpdv->dv_unit, 1);
770 	}
771 
772  out:
773 	printf(" dumps on %s%c\n", dumpdv->dv_xname, DISKPART(dumpdev) + 'a');
774 	return;
775 
776  nodumpdev:
777 	dumpdev = NODEV;
778 	if (print_newline)
779 		printf("\n");
780 }
781 
782 static int
783 findblkmajor(name, nam2blk)
784 	const char *name;
785 	struct devnametobdevmaj *nam2blk;
786 {
787 	int i;
788 
789 	if (nam2blk == NULL)
790 		return (-1);
791 
792 	for (i = 0; nam2blk[i].d_name != NULL; i++)
793 		if (strncmp(name, nam2blk[i].d_name,
794 		    strlen(nam2blk[i].d_name)) == 0)
795 			return (nam2blk[i].d_maj);
796 	return (-1);
797 }
798 
799 const char *
800 findblkname(maj, nam2blk)
801 	int maj;
802 	struct devnametobdevmaj *nam2blk;
803 {
804 	int i;
805 
806 	if (nam2blk == NULL)
807 		return (NULL);
808 
809 	for (i = 0; nam2blk[i].d_name != NULL; i++)
810 		if (nam2blk[i].d_maj == maj)
811 			return (nam2blk[i].d_name);
812 	return (NULL);
813 }
814 
815 static struct device *
816 getdisk(str, len, defpart, nam2blk, devp, isdump)
817 	char *str;
818 	int len, defpart;
819 	struct devnametobdevmaj *nam2blk;
820 	dev_t *devp;
821 	int isdump;
822 {
823 	struct device	*dv;
824 #ifdef MEMORY_DISK_HOOKS
825 	int		i;
826 #endif
827 
828 	if ((dv = parsedisk(str, len, defpart, nam2blk, devp)) == NULL) {
829 		printf("use one of:");
830 #ifdef MEMORY_DISK_HOOKS
831 		if (isdump == 0)
832 			for (i = 0; i < NMD; i++)
833 				printf(" %s[a-%c]", fakemdrootdev[i].dv_xname,
834 				    'a' + MAXPARTITIONS - 1);
835 #endif
836 		for (dv = alldevs.tqh_first; dv != NULL;
837 		    dv = dv->dv_list.tqe_next) {
838 			if (dv->dv_class == DV_DISK)
839 				printf(" %s[a-%c]", dv->dv_xname,
840 				    'a' + MAXPARTITIONS - 1);
841 			if (isdump == 0 && dv->dv_class == DV_IFNET)
842 				printf(" %s", dv->dv_xname);
843 		}
844 		if (isdump)
845 			printf(" none");
846 		printf(" halt\n");
847 	}
848 	return (dv);
849 }
850 
851 static struct device *
852 parsedisk(str, len, defpart, nam2blk, devp)
853 	char *str;
854 	int len, defpart;
855 	struct devnametobdevmaj *nam2blk;
856 	dev_t *devp;
857 {
858 	struct device *dv;
859 	char *cp, c;
860 	int majdev, part;
861 #ifdef MEMORY_DISK_HOOKS
862 	int i;
863 #endif
864 
865 	if (len == 0)
866 		return (NULL);
867 
868 	if (len == 4 && strcmp(str, "halt") == 0)
869 		cpu_reboot(RB_HALT, NULL);
870 
871 	cp = str + len - 1;
872 	c = *cp;
873 	if (c >= 'a' && c <= ('a' + MAXPARTITIONS - 1)) {
874 		part = c - 'a';
875 		*cp = '\0';
876 	} else
877 		part = defpart;
878 
879 #ifdef MEMORY_DISK_HOOKS
880 	for (i = 0; i < NMD; i++)
881 		if (strcmp(str, fakemdrootdev[i].dv_xname) == 0) {
882 			dv = &fakemdrootdev[i];
883 			goto gotdisk;
884 		}
885 #endif
886 
887 	for (dv = alldevs.tqh_first; dv != NULL; dv = dv->dv_list.tqe_next) {
888 		if (dv->dv_class == DV_DISK &&
889 		    strcmp(str, dv->dv_xname) == 0) {
890 #ifdef MEMORY_DISK_HOOKS
891  gotdisk:
892 #endif
893 			majdev = findblkmajor(dv->dv_xname, nam2blk);
894 			if (majdev < 0)
895 				panic("parsedisk");
896 			*devp = MAKEDISKDEV(majdev, dv->dv_unit, part);
897 			break;
898 		}
899 
900 		if (dv->dv_class == DV_IFNET &&
901 		    strcmp(str, dv->dv_xname) == 0) {
902 			*devp = NODEV;
903 			break;
904 		}
905 	}
906 
907 	*cp = c;
908 	return (dv);
909 }
910 
911 /*
912  * XXX shouldn't this be a common function?
913  */
914 static int
915 getstr(cp, size)
916 	char *cp;
917 	int size;
918 {
919 	char *lp;
920 	int c, len;
921 
922 	cnpollc(1);
923 
924 	lp = cp;
925 	len = 0;
926 	for (;;) {
927 		c = cngetc();
928 		switch (c) {
929 		case '\n':
930 		case '\r':
931 			printf("\n");
932 			*lp++ = '\0';
933 			cnpollc(0);
934 			return (len);
935 		case '\b':
936 		case '\177':
937 		case '#':
938 			if (len) {
939 				--len;
940 				--lp;
941 				printf("\b \b");
942 			}
943 			continue;
944 		case '@':
945 		case 'u'&037:
946 			len = 0;
947 			lp = cp;
948 			printf("\n");
949 			continue;
950 		default:
951 			if (len + 1 >= size || c < ' ') {
952 				printf("\007");
953 				continue;
954 			}
955 			printf("%c", c);
956 			++len;
957 			*lp++ = c;
958 		}
959 	}
960 }
961