xref: /netbsd-src/sys/kern/kern_subr.c (revision dc306354b0b29af51801a7632f1e95265a68cd81)
1 /*	$NetBSD: kern_subr.c,v 1.41 1998/08/04 04:03:14 perry 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_uvm.h"
93 
94 #include <sys/param.h>
95 #include <sys/systm.h>
96 #include <sys/proc.h>
97 #include <sys/malloc.h>
98 #include <sys/mount.h>
99 #include <sys/device.h>
100 #include <sys/reboot.h>
101 #include <sys/conf.h>
102 #include <sys/disklabel.h>
103 #include <sys/queue.h>
104 
105 #include <dev/cons.h>
106 
107 #include <net/if.h>
108 
109 /* XXX these should eventually move to subr_autoconf.c */
110 static int findblkmajor __P((const char *, struct devnametobdevmaj *));
111 static const char *findblkname __P((int, struct devnametobdevmaj *));
112 static struct device *getdisk __P((char *, int, int,
113 	struct devnametobdevmaj *, dev_t *, int));
114 static struct device *parsedisk __P((char *, int, int,
115 	struct devnametobdevmaj *, dev_t *));
116 static int getstr __P((char *, int));
117 
118 int
119 uiomove(buf, n, uio)
120 	register void *buf;
121 	register int n;
122 	register struct uio *uio;
123 {
124 	register struct iovec *iov;
125 	u_int cnt;
126 	int error = 0;
127 	char *cp = buf;
128 
129 #ifdef DIAGNOSTIC
130 	if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
131 		panic("uiomove: mode");
132 	if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
133 		panic("uiomove proc");
134 #endif
135 	while (n > 0 && uio->uio_resid) {
136 		iov = uio->uio_iov;
137 		cnt = iov->iov_len;
138 		if (cnt == 0) {
139 			uio->uio_iov++;
140 			uio->uio_iovcnt--;
141 			continue;
142 		}
143 		if (cnt > n)
144 			cnt = n;
145 		switch (uio->uio_segflg) {
146 
147 		case UIO_USERSPACE:
148 			if (uio->uio_rw == UIO_READ)
149 				error = copyout(cp, iov->iov_base, cnt);
150 			else
151 				error = copyin(iov->iov_base, cp, cnt);
152 			if (error)
153 				return (error);
154 			break;
155 
156 		case UIO_SYSSPACE:
157 #if defined(UVM)
158 			if (uio->uio_rw == UIO_READ)
159 				error = kcopy(cp, iov->iov_base, cnt);
160 			else
161 				error = kcopy(iov->iov_base, cp, cnt);
162 			if (error)
163 				return(error);
164 #else
165 			if (uio->uio_rw == UIO_READ)
166 				memcpy(iov->iov_base, cp, cnt);
167 			else
168 				memcpy(cp, iov->iov_base, cnt);
169 #endif
170 			break;
171 		}
172 		(caddr_t)iov->iov_base += cnt;
173 		iov->iov_len -= cnt;
174 		uio->uio_resid -= cnt;
175 		uio->uio_offset += cnt;
176 		cp += cnt;
177 		n -= cnt;
178 	}
179 	return (error);
180 }
181 
182 /*
183  * Give next character to user as result of read.
184  */
185 int
186 ureadc(c, uio)
187 	register int c;
188 	register struct uio *uio;
189 {
190 	register struct iovec *iov;
191 
192 	if (uio->uio_resid <= 0)
193 		panic("ureadc: non-positive resid");
194 again:
195 	if (uio->uio_iovcnt <= 0)
196 		panic("ureadc: non-positive iovcnt");
197 	iov = uio->uio_iov;
198 	if (iov->iov_len <= 0) {
199 		uio->uio_iovcnt--;
200 		uio->uio_iov++;
201 		goto again;
202 	}
203 	switch (uio->uio_segflg) {
204 
205 	case UIO_USERSPACE:
206 		if (subyte(iov->iov_base, c) < 0)
207 			return (EFAULT);
208 		break;
209 
210 	case UIO_SYSSPACE:
211 		*(char *)iov->iov_base = c;
212 		break;
213 	}
214 	((caddr_t)iov->iov_base)++;
215 	iov->iov_len--;
216 	uio->uio_resid--;
217 	uio->uio_offset++;
218 	return (0);
219 }
220 
221 /*
222  * General routine to allocate a hash table.
223  */
224 void *
225 hashinit(elements, type, flags, hashmask)
226 	int elements, type, flags;
227 	u_long *hashmask;
228 {
229 	long hashsize;
230 	LIST_HEAD(generic, generic) *hashtbl;
231 	int i;
232 
233 	if (elements <= 0)
234 		panic("hashinit: bad cnt");
235 	for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
236 		continue;
237 	hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, flags);
238 	for (i = 0; i < hashsize; i++)
239 		LIST_INIT(&hashtbl[i]);
240 	*hashmask = hashsize - 1;
241 	return (hashtbl);
242 }
243 
244 /*
245  * "Shutdown hook" types, functions, and variables.
246  */
247 
248 struct shutdownhook_desc {
249 	LIST_ENTRY(shutdownhook_desc) sfd_list;
250 	void	(*sfd_fn) __P((void *));
251 	void	*sfd_arg;
252 };
253 
254 LIST_HEAD(, shutdownhook_desc) shutdownhook_list;
255 
256 void *
257 shutdownhook_establish(fn, arg)
258 	void (*fn) __P((void *));
259 	void *arg;
260 {
261 	struct shutdownhook_desc *ndp;
262 
263 	ndp = (struct shutdownhook_desc *)
264 	    malloc(sizeof(*ndp), M_DEVBUF, M_NOWAIT);
265 	if (ndp == NULL)
266 		return NULL;
267 
268 	ndp->sfd_fn = fn;
269 	ndp->sfd_arg = arg;
270 	LIST_INSERT_HEAD(&shutdownhook_list, ndp, sfd_list);
271 
272 	return (ndp);
273 }
274 
275 void
276 shutdownhook_disestablish(vhook)
277 	void *vhook;
278 {
279 #ifdef DIAGNOSTIC
280 	struct shutdownhook_desc *dp;
281 
282 	for (dp = shutdownhook_list.lh_first; dp != NULL;
283 	    dp = dp->sfd_list.le_next)
284                 if (dp == vhook)
285 			break;
286 	if (dp == NULL)
287 		panic("shutdownhook_disestablish: hook not established");
288 #endif
289 
290 	LIST_REMOVE((struct shutdownhook_desc *)vhook, sfd_list);
291 	free(vhook, M_DEVBUF);
292 }
293 
294 /*
295  * Run shutdown hooks.  Should be invoked immediately before the
296  * system is halted or rebooted, i.e. after file systems unmounted,
297  * after crash dump done, etc.
298  *
299  * Each shutdown hook is removed from the list before it's run, so that
300  * it won't be run again.
301  */
302 void
303 doshutdownhooks()
304 {
305 	struct shutdownhook_desc *dp;
306 
307 	while ((dp = shutdownhook_list.lh_first) != NULL) {
308 		LIST_REMOVE(dp, sfd_list);
309 		(*dp->sfd_fn)(dp->sfd_arg);
310 #if 0
311 		/*
312 		 * Don't bother freeing the hook structure,, since we may
313 		 * be rebooting because of a memory corruption problem,
314 		 * and this might only make things worse.  It doesn't
315 		 * matter, anyway, since the system is just about to
316 		 * reboot.
317 		 */
318 		free(dp, M_DEVBUF);
319 #endif
320 	}
321 }
322 
323 /*
324  * "Mountroot hook" types, functions, and variables.
325  */
326 
327 struct mountroothook_desc {
328 	LIST_ENTRY(mountroothook_desc) mrd_list;
329 	struct	device *mrd_device;
330 	void 	(*mrd_func) __P((struct device *));
331 };
332 
333 LIST_HEAD(, mountroothook_desc) mountroothook_list;
334 
335 void *
336 mountroothook_establish(func, dev)
337 	void (*func) __P((struct device *));
338 	struct device *dev;
339 {
340 	struct mountroothook_desc *mrd;
341 
342 	mrd = (struct mountroothook_desc *)
343 	    malloc(sizeof(*mrd), M_DEVBUF, M_NOWAIT);
344 	if (mrd == NULL)
345 		return (NULL);
346 
347 	mrd->mrd_device = dev;
348 	mrd->mrd_func = func;
349 	LIST_INSERT_HEAD(&mountroothook_list, mrd, mrd_list);
350 
351 	return (mrd);
352 }
353 
354 void
355 mountroothook_disestablish(vhook)
356 	void *vhook;
357 {
358 #ifdef DIAGNOSTIC
359 	struct mountroothook_desc *mrd;
360 
361 	for (mrd = mountroothook_list.lh_first; mrd != NULL;
362 	    mrd = mrd->mrd_list.le_next)
363                 if (mrd == vhook)
364 			break;
365 	if (mrd == NULL)
366 		panic("mountroothook_disestablish: hook not established");
367 #endif
368 
369 	LIST_REMOVE((struct mountroothook_desc *)vhook, mrd_list);
370 	free(vhook, M_DEVBUF);
371 }
372 
373 void
374 mountroothook_destroy()
375 {
376 	struct mountroothook_desc *mrd;
377 
378 	while ((mrd = mountroothook_list.lh_first) != NULL) {
379 		LIST_REMOVE(mrd, mrd_list);
380 		free(mrd, M_DEVBUF);
381 	}
382 }
383 
384 void
385 domountroothook()
386 {
387 	struct mountroothook_desc *mrd;
388 
389 	for (mrd = mountroothook_list.lh_first; mrd != NULL;
390 	    mrd = mrd->mrd_list.le_next) {
391 		if (mrd->mrd_device == root_device) {
392 			(*mrd->mrd_func)(root_device);
393 			return;
394 		}
395 	}
396 }
397 
398 /*
399  * Determine the root device and, if instructed to, the root file system.
400  */
401 
402 #include "md.h"
403 #if NMD == 0
404 #undef MEMORY_DISK_HOOKS
405 #endif
406 
407 #ifdef MEMORY_DISK_HOOKS
408 static struct device fakemdrootdev[NMD];
409 #endif
410 
411 void
412 setroot(bootdv, bootpartition, nam2blk)
413 	struct device *bootdv;
414 	int bootpartition;
415 	struct devnametobdevmaj *nam2blk;
416 {
417 	struct device *dv;
418 	int len, print_newline = 0;
419 #ifdef MEMORY_DISK_HOOKS
420 	int i;
421 #endif
422 	dev_t nrootdev;
423 	dev_t ndumpdev = NODEV;
424 	char buf[128];
425 	const char *rootdevname;
426 	const char *dumpdevname;
427 	struct device *rootdv = NULL;		/* XXX gcc -Wuninitialized */
428 	struct device *dumpdv = NULL;
429 	struct ifnet *ifp;
430 	const char *deffsname;
431 	struct vfsops *vops;
432 	extern int (*mountroot) __P((void));
433 	static struct devnametobdevmaj *last_nam2blk;
434 
435 	if (nam2blk == NULL) {
436 		if (last_nam2blk == NULL)
437 			panic("setroot: no name to bdev major map");
438 		nam2blk = last_nam2blk;
439 	}
440 	last_nam2blk = nam2blk;
441 
442 #ifdef MEMORY_DISK_HOOKS
443 	for (i = 0; i < NMD; i++) {
444 		fakemdrootdev[i].dv_class  = DV_DISK;
445 		fakemdrootdev[i].dv_cfdata = NULL;
446 		fakemdrootdev[i].dv_unit   = i;
447 		fakemdrootdev[i].dv_parent = NULL;
448 		sprintf(fakemdrootdev[i].dv_xname, "md%d", i);
449 	}
450 #endif /* MEMORY_DISK_HOOKS */
451 
452 #ifdef MEMORY_DISK_IS_ROOT
453 	bootdv = &fakemdrootdev[0];
454 	bootpartition = 0;
455 #endif
456 
457 	/*
458 	 * If NFS is specified as the file system, and we found
459 	 * a DV_DISK boot device (or no boot device at all), then
460 	 * find a reasonable network interface for "rootspec".
461 	 */
462 	vops = vfs_getopsbyname("nfs");
463 	if (vops != NULL && vops->vfs_mountroot == mountroot &&
464 	    rootspec == NULL &&
465 	    (bootdv == NULL || bootdv->dv_class != DV_IFNET)) {
466 		for (ifp = ifnet.tqh_first; ifp != NULL;
467 		    ifp = ifp->if_list.tqe_next)
468 			if ((ifp->if_flags &
469 			     (IFF_LOOPBACK|IFF_POINTOPOINT)) == 0)
470 				break;
471 		if (ifp == NULL) {
472 			/*
473 			 * Can't find a suitable interface; ask the
474 			 * user.
475 			 */
476 			boothowto |= RB_ASKNAME;
477 		} else {
478 			/*
479 			 * Have a suitable interface; behave as if
480 			 * the user specified this interface.
481 			 */
482 			rootspec = (const char *)ifp->if_xname;
483 		}
484 	}
485 
486 	/*
487 	 * If wildcarded root and we the boot device wasn't determined,
488 	 * ask the user.
489 	 */
490 	if (rootspec == NULL && bootdv == NULL)
491 		boothowto |= RB_ASKNAME;
492 
493  top:
494 	if (boothowto & RB_ASKNAME) {
495 		struct device *defdumpdv;
496 
497 		for (;;) {
498 			printf("root device");
499 			if (bootdv != NULL) {
500 				printf(" (default %s", bootdv->dv_xname);
501 				if (bootdv->dv_class == DV_DISK)
502 					printf("%c", bootpartition + 'a');
503 				printf(")");
504 			}
505 			printf(": ");
506 			len = getstr(buf, sizeof(buf));
507 			if (len == 0 && bootdv != NULL) {
508 				strcpy(buf, bootdv->dv_xname);
509 				len = strlen(buf);
510 			}
511 			if (len > 0 && buf[len - 1] == '*') {
512 				buf[--len] = '\0';
513 				dv = getdisk(buf, len, 1, nam2blk,
514 				    &nrootdev, 0);
515 				if (dv != NULL) {
516 					rootdv = dv;
517 					break;
518 				}
519 			}
520 			dv = getdisk(buf, len, bootpartition, nam2blk,
521 			    &nrootdev, 0);
522 			if (dv != NULL) {
523 				rootdv = dv;
524 				break;
525 			}
526 		}
527 
528 		/*
529 		 * Set up the default dump device.  If root is on
530 		 * a network device, there is no default dump
531 		 * device, since we don't support dumps to the
532 		 * network.
533 		 */
534 		if (rootdv->dv_class == DV_IFNET)
535 			defdumpdv = NULL;
536 		else
537 			defdumpdv = rootdv;
538 
539 		for (;;) {
540 			printf("dump device");
541 			if (defdumpdv != NULL) {
542 				/*
543 				 * Note, we know it's a disk if we get here.
544 				 */
545 				printf(" (default %sb)", defdumpdv->dv_xname);
546 			}
547 			printf(": ");
548 			len = getstr(buf, sizeof(buf));
549 			if (len == 0) {
550 				if (defdumpdv != NULL) {
551 					ndumpdev = MAKEDISKDEV(major(nrootdev),
552 					    DISKUNIT(nrootdev), 1);
553 				}
554 				if (rootdv->dv_class == DV_IFNET)
555 					dumpdv = NULL;
556 				else
557 					dumpdv = rootdv;
558 				break;
559 			}
560 			if (len == 4 && strcmp(buf, "none") == 0) {
561 				dumpspec = "none";
562 				goto havedump;
563 			}
564 			dv = getdisk(buf, len, 1, nam2blk, &ndumpdev, 1);
565 			if (dv) {
566 				dumpdv = dv;
567 				break;
568 			}
569 		}
570 
571  havedump:
572 		rootdev = nrootdev;
573 		dumpdev = ndumpdev;
574 
575 		for (vops = LIST_FIRST(&vfs_list); vops != NULL;
576 		     vops = LIST_NEXT(vops, vfs_list)) {
577 			if (vops->vfs_mountroot != NULL &&
578 			    vops->vfs_mountroot == mountroot)
579 			break;
580 		}
581 
582 		if (vops == NULL) {
583 			mountroot = NULL;
584 			deffsname = "generic";
585 		} else
586 			deffsname = vops->vfs_name;
587 
588 		for (;;) {
589 			printf("file system (default %s): ", deffsname);
590 			len = getstr(buf, sizeof(buf));
591 			if (len == 0)
592 				break;
593 			if (len == 4 && strcmp(buf, "halt") == 0)
594 				cpu_reboot(RB_HALT, NULL);
595 			else if (len == 7 && strcmp(buf, "generic") == 0) {
596 				mountroot = NULL;
597 				break;
598 			}
599 			vops = vfs_getopsbyname(buf);
600 			if (vops == NULL || vops->vfs_mountroot == NULL) {
601 				printf("use one of: generic");
602 				for (vops = LIST_FIRST(&vfs_list);
603 				     vops != NULL;
604 				     vops = LIST_NEXT(vops, vfs_list)) {
605 					if (vops->vfs_mountroot != NULL)
606 						printf(" %s", vops->vfs_name);
607 				}
608 				printf(" halt\n");
609 			} else {
610 				mountroot = vops->vfs_mountroot;
611 				break;
612 			}
613 		}
614 
615 	} else if (rootspec == NULL) {
616 		int majdev;
617 
618 		/*
619 		 * Wildcarded root; use the boot device.
620 		 */
621 		rootdv = bootdv;
622 
623 		majdev = findblkmajor(bootdv->dv_xname, nam2blk);
624 		if (majdev >= 0) {
625 			/*
626 			 * Root is on a disk.  `bootpartition' is root.
627 			 */
628 			rootdev = MAKEDISKDEV(majdev, bootdv->dv_unit,
629 			    bootpartition);
630 		}
631 	} else {
632 
633 		/*
634 		 * `root on <dev> ...'
635 		 */
636 
637 		/*
638 		 * If it's a network interface, we can bail out
639 		 * early.
640 		 */
641 		for (dv = alldevs.tqh_first; dv != NULL;
642 		    dv = dv->dv_list.tqe_next)
643 			if (strcmp(dv->dv_xname, rootspec) == 0)
644 				break;
645 		if (dv != NULL && dv->dv_class == DV_IFNET) {
646 			rootdv = dv;
647 			goto haveroot;
648 		}
649 
650 		rootdevname = findblkname(major(rootdev), nam2blk);
651 		if (rootdevname == NULL) {
652 			printf("unknown device major 0x%x\n", rootdev);
653 			boothowto |= RB_ASKNAME;
654 			goto top;
655 		}
656 		memset(buf, 0, sizeof(buf));
657 		sprintf(buf, "%s%d", rootdevname, DISKUNIT(rootdev));
658 
659 		for (dv = alldevs.tqh_first; dv != NULL;
660 		    dv = dv->dv_list.tqe_next) {
661 			if (strcmp(buf, dv->dv_xname) == 0) {
662 				rootdv = dv;
663 				break;
664 			}
665 		}
666 		if (rootdv == NULL) {
667 			printf("device %s (0x%x) not configured\n",
668 			    buf, rootdev);
669 			boothowto |= RB_ASKNAME;
670 			goto top;
671 		}
672 	}
673 
674  haveroot:
675 
676 	root_device = rootdv;
677 
678 	switch (rootdv->dv_class) {
679 	case DV_IFNET:
680 		/* Nothing. */
681 		break;
682 
683 	case DV_DISK:
684 		printf("root on %s%c", rootdv->dv_xname,
685 		    DISKPART(rootdev) + 'a');
686 		print_newline = 1;
687 		break;
688 
689 	default:
690 		printf("can't determine root device\n");
691 		boothowto |= RB_ASKNAME;
692 		goto top;
693 	}
694 
695 	/*
696 	 * Now configure the dump device.
697 	 */
698 
699 	if (dumpspec != NULL && strcmp(dumpspec, "none") == 0) {
700 		/*
701 		 * Operator doesn't want a dump device.
702 		 */
703 		goto nodumpdev;
704 	}
705 
706 	/*
707 	 * If we haven't figured out the dump device, do so, with
708 	 * the following rules:
709 	 *
710 	 *	(a) We already know dumpdv in the RB_ASKNAME case.
711 	 *
712 	 *	(b) If dumpspec is set, try to use it.  If the device
713 	 *	    is not available, punt.
714 	 *
715 	 *	(c) If dumpspec is not set, the dump device is
716 	 *	    wildcarded or unspecified.  If the root device
717 	 *	    is DV_IFNET, punt.  Otherwise, use partition b
718 	 *	    of the root device.
719 	 */
720 
721 	if (boothowto & RB_ASKNAME) {
722 		if (dumpdv == NULL) {
723 			/*
724 			 * Just return; dumpdev is already set to NODEV
725 			 * and we don't want to print a newline in this
726 			 * case.
727 			 */
728 			return;
729 		}
730 		goto out;
731 	}
732 
733 	if (dumpspec != NULL) {
734 		if (dumpdev == NODEV) {
735 			/*
736 			 * Looks like they tried to pick a network
737 			 * device.  Oops.
738 			 */
739 			goto nodumpdev;
740 		}
741 
742 		dumpdevname = findblkname(major(dumpdev), nam2blk);
743 		if (dumpdevname == NULL)
744 			goto nodumpdev;
745 		memset(buf, 0, sizeof(buf));
746 		sprintf(buf, "%s%d", dumpdevname, DISKUNIT(dumpdev));
747 
748 		for (dv = alldevs.tqh_first; dv != NULL;
749 		    dv = dv->dv_list.tqe_next) {
750 			if (strcmp(buf, dv->dv_xname) == 0) {
751 				dumpdv = dv;
752 				break;
753 			}
754 		}
755 		if (dv == NULL) {
756 			/*
757 			 * Device not configured.
758 			 */
759 			goto nodumpdev;
760 		}
761 	} else if (rootdv->dv_class == DV_IFNET)
762 		goto nodumpdev;
763 	else {
764 		dumpdv = rootdv;
765 		dumpdev = MAKEDISKDEV(major(rootdev), dumpdv->dv_unit, 1);
766 	}
767 
768  out:
769 	printf(" dumps on %s%c\n", dumpdv->dv_xname, DISKPART(dumpdev) + 'a');
770 	return;
771 
772  nodumpdev:
773 	dumpdev = NODEV;
774 	if (print_newline)
775 		printf("\n");
776 }
777 
778 static int
779 findblkmajor(name, nam2blk)
780 	const char *name;
781 	struct devnametobdevmaj *nam2blk;
782 {
783 	int i;
784 
785 	if (nam2blk == NULL)
786 		return (-1);
787 
788 	for (i = 0; nam2blk[i].d_name != NULL; i++)
789 		if (strncmp(name, nam2blk[i].d_name,
790 		    strlen(nam2blk[i].d_name)) == 0)
791 			return (nam2blk[i].d_maj);
792 	return (-1);
793 }
794 
795 const char *
796 findblkname(maj, nam2blk)
797 	int maj;
798 	struct devnametobdevmaj *nam2blk;
799 {
800 	int i;
801 
802 	if (nam2blk == NULL)
803 		return (NULL);
804 
805 	for (i = 0; nam2blk[i].d_name != NULL; i++)
806 		if (nam2blk[i].d_maj == maj)
807 			return (nam2blk[i].d_name);
808 	return (NULL);
809 }
810 
811 static struct device *
812 getdisk(str, len, defpart, nam2blk, devp, isdump)
813 	char *str;
814 	int len, defpart;
815 	struct devnametobdevmaj *nam2blk;
816 	dev_t *devp;
817 	int isdump;
818 {
819 	struct device	*dv;
820 #ifdef MEMORY_DISK_HOOKS
821 	int		i;
822 #endif
823 
824 	if ((dv = parsedisk(str, len, defpart, nam2blk, devp)) == NULL) {
825 		printf("use one of:");
826 #ifdef MEMORY_DISK_HOOKS
827 		if (isdump == 0)
828 			for (i = 0; i < NMD; i++)
829 				printf(" %s[a-%c]", fakemdrootdev[i].dv_xname,
830 				    'a' + MAXPARTITIONS - 1);
831 #endif
832 		for (dv = alldevs.tqh_first; dv != NULL;
833 		    dv = dv->dv_list.tqe_next) {
834 			if (dv->dv_class == DV_DISK)
835 				printf(" %s[a-%c]", dv->dv_xname,
836 				    'a' + MAXPARTITIONS - 1);
837 			if (isdump == 0 && dv->dv_class == DV_IFNET)
838 				printf(" %s", dv->dv_xname);
839 		}
840 		if (isdump)
841 			printf(" none");
842 		printf(" halt\n");
843 	}
844 	return (dv);
845 }
846 
847 static struct device *
848 parsedisk(str, len, defpart, nam2blk, devp)
849 	char *str;
850 	int len, defpart;
851 	struct devnametobdevmaj *nam2blk;
852 	dev_t *devp;
853 {
854 	struct device *dv;
855 	char *cp, c;
856 	int majdev, part;
857 #ifdef MEMORY_DISK_HOOKS
858 	int i;
859 #endif
860 
861 	if (len == 0)
862 		return (NULL);
863 
864 	if (len == 4 && strcmp(str, "halt") == 0)
865 		cpu_reboot(RB_HALT, NULL);
866 
867 	cp = str + len - 1;
868 	c = *cp;
869 	if (c >= 'a' && c <= ('a' + MAXPARTITIONS - 1)) {
870 		part = c - 'a';
871 		*cp = '\0';
872 	} else
873 		part = defpart;
874 
875 #ifdef MEMORY_DISK_HOOKS
876 	for (i = 0; i < NMD; i++)
877 		if (strcmp(str, fakemdrootdev[i].dv_xname) == 0) {
878 			dv = &fakemdrootdev[i];
879 			goto gotdisk;
880 		}
881 #endif
882 
883 	for (dv = alldevs.tqh_first; dv != NULL; dv = dv->dv_list.tqe_next) {
884 		if (dv->dv_class == DV_DISK &&
885 		    strcmp(str, dv->dv_xname) == 0) {
886 #ifdef MEMORY_DISK_HOOKS
887  gotdisk:
888 #endif
889 			majdev = findblkmajor(dv->dv_xname, nam2blk);
890 			if (majdev < 0)
891 				panic("parsedisk");
892 			*devp = MAKEDISKDEV(majdev, dv->dv_unit, part);
893 			break;
894 		}
895 
896 		if (dv->dv_class == DV_IFNET &&
897 		    strcmp(str, dv->dv_xname) == 0) {
898 			*devp = NODEV;
899 			break;
900 		}
901 	}
902 
903 	*cp = c;
904 	return (dv);
905 }
906 
907 /*
908  * XXX shouldn't this be a common function?
909  */
910 static int
911 getstr(cp, size)
912 	char *cp;
913 	int size;
914 {
915 	char *lp;
916 	int c, len;
917 
918 	cnpollc(1);
919 
920 	lp = cp;
921 	len = 0;
922 	for (;;) {
923 		c = cngetc();
924 		switch (c) {
925 		case '\n':
926 		case '\r':
927 			printf("\n");
928 			*lp++ = '\0';
929 			cnpollc(0);
930 			return (len);
931 		case '\b':
932 		case '\177':
933 		case '#':
934 			if (len) {
935 				--len;
936 				--lp;
937 				printf("\b \b");
938 			}
939 			continue;
940 		case '@':
941 		case 'u'&037:
942 			len = 0;
943 			lp = cp;
944 			printf("\n");
945 			continue;
946 		default:
947 			if (len + 1 >= size || c < ' ') {
948 				printf("\007");
949 				continue;
950 			}
951 			printf("%c", c);
952 			++len;
953 			*lp++ = c;
954 		}
955 	}
956 }
957