xref: /dflybsd-src/sys/kern/kern_shutdown.c (revision c10aefeb9519a74394a6efad0e60a96c9c28cfde)
1 /*-
2  * Copyright (c) 1986, 1988, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)kern_shutdown.c	8.3 (Berkeley) 1/21/94
39  * $FreeBSD: src/sys/kern/kern_shutdown.c,v 1.72.2.12 2002/02/21 19:15:10 dillon Exp $
40  * $DragonFly: src/sys/kern/kern_shutdown.c,v 1.25 2006/02/21 17:36:38 dillon Exp $
41  */
42 
43 #include "opt_ddb.h"
44 #include "opt_ddb_trace.h"
45 #include "opt_hw_wdog.h"
46 #include "opt_panic.h"
47 #include "opt_show_busybufs.h"
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/eventhandler.h>
52 #include <sys/buf.h>
53 #include <sys/disklabel.h>
54 #include <sys/reboot.h>
55 #include <sys/proc.h>
56 #include <sys/vnode.h>
57 #include <sys/kernel.h>
58 #include <sys/kthread.h>
59 #include <sys/malloc.h>
60 #include <sys/mount.h>
61 #include <sys/queue.h>
62 #include <sys/sysctl.h>
63 #include <sys/conf.h>
64 #include <sys/sysproto.h>
65 #include <sys/device.h>
66 #include <sys/cons.h>
67 #include <sys/thread2.h>
68 #include <sys/buf2.h>
69 
70 #include <machine/pcb.h>
71 #include <machine/clock.h>
72 #include <machine/md_var.h>
73 #include <machine/smp.h>		/* smp_active_mask, cpuid */
74 
75 #include <sys/signalvar.h>
76 
77 #ifndef PANIC_REBOOT_WAIT_TIME
78 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
79 #endif
80 
81 /*
82  * Note that stdarg.h and the ANSI style va_start macro is used for both
83  * ANSI and traditional C compilers.  We use the machine version to stay
84  * within the confines of the kernel header files.
85  */
86 #include <machine/stdarg.h>
87 
88 #ifdef DDB
89 #ifdef DDB_UNATTENDED
90 int debugger_on_panic = 0;
91 #else
92 int debugger_on_panic = 1;
93 #endif
94 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW,
95 	&debugger_on_panic, 0, "Run debugger on kernel panic");
96 
97 extern void db_print_backtrace(void);
98 
99 #ifdef DDB_TRACE
100 int trace_on_panic = 1;
101 #else
102 int trace_on_panic = 0;
103 #endif
104 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW,
105 	&trace_on_panic, 0, "Print stack trace on kernel panic");
106 #endif
107 
108 static int sync_on_panic = 1;
109 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW,
110 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
111 
112 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
113 
114 #ifdef	HW_WDOG
115 /*
116  * If there is a hardware watchdog, point this at the function needed to
117  * hold it off.
118  * It's needed when the kernel needs to do some lengthy operations.
119  * e.g. in wd.c when dumping core.. It's most annoying to have
120  * your precious core-dump only half written because the wdog kicked in.
121  */
122 watchdog_tickle_fn wdog_tickler = NULL;
123 #endif	/* HW_WDOG */
124 
125 /*
126  * Variable panicstr contains argument to first call to panic; used as flag
127  * to indicate that the kernel has already called panic.
128  */
129 const char *panicstr;
130 
131 int dumping;				/* system is dumping */
132 #ifdef SMP
133 u_int panic_cpu_interlock;		/* panic interlock */
134 globaldata_t panic_cpu_gd;		/* which cpu took the panic */
135 #endif
136 
137 static void boot (int) __dead2;
138 static void dumpsys (void);
139 static int setdumpdev (dev_t dev);
140 static void poweroff_wait (void *, int);
141 static void print_uptime (void);
142 static void shutdown_halt (void *junk, int howto);
143 static void shutdown_panic (void *junk, int howto);
144 static void shutdown_reset (void *junk, int howto);
145 
146 /* register various local shutdown events */
147 static void
148 shutdown_conf(void *unused)
149 {
150 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL, SHUTDOWN_PRI_FIRST);
151 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL, SHUTDOWN_PRI_LAST + 100);
152 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL, SHUTDOWN_PRI_LAST + 100);
153 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL, SHUTDOWN_PRI_LAST + 200);
154 }
155 
156 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL)
157 
158 /* ARGSUSED */
159 
160 /*
161  * The system call that results in a reboot
162  */
163 int
164 reboot(struct reboot_args *uap)
165 {
166 	struct thread *td = curthread;
167 	int error;
168 
169 	if ((error = suser(td)))
170 		return (error);
171 
172 	boot(uap->opt);
173 	return (0);
174 }
175 
176 /*
177  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
178  */
179 static int shutdown_howto = 0;
180 
181 void
182 shutdown_nice(int howto)
183 {
184 	shutdown_howto = howto;
185 
186 	/* Send a signal to init(8) and have it shutdown the world */
187 	if (initproc != NULL) {
188 		psignal(initproc, SIGINT);
189 	} else {
190 		/* No init(8) running, so simply reboot */
191 		boot(RB_NOSYNC);
192 	}
193 	return;
194 }
195 static int	waittime = -1;
196 static struct pcb dumppcb;
197 
198 static void
199 print_uptime()
200 {
201 	int f;
202 	struct timespec ts;
203 
204 	getnanouptime(&ts);
205 	printf("Uptime: ");
206 	f = 0;
207 	if (ts.tv_sec >= 86400) {
208 		printf("%ldd", ts.tv_sec / 86400);
209 		ts.tv_sec %= 86400;
210 		f = 1;
211 	}
212 	if (f || ts.tv_sec >= 3600) {
213 		printf("%ldh", ts.tv_sec / 3600);
214 		ts.tv_sec %= 3600;
215 		f = 1;
216 	}
217 	if (f || ts.tv_sec >= 60) {
218 		printf("%ldm", ts.tv_sec / 60);
219 		ts.tv_sec %= 60;
220 		f = 1;
221 	}
222 	printf("%lds\n", ts.tv_sec);
223 }
224 
225 /*
226  *  Go through the rigmarole of shutting down..
227  * this used to be in machdep.c but I'll be dammned if I could see
228  * anything machine dependant in it.
229  */
230 static void
231 boot(int howto)
232 {
233 	/*
234 	 * Get rid of any user scheduler baggage and then give
235 	 * us a high priority.
236 	 */
237 	if (curthread->td_release)
238 		curthread->td_release(curthread);
239 	lwkt_setpri_self(TDPRI_MAX);
240 
241 	/* collect extra flags that shutdown_nice might have set */
242 	howto |= shutdown_howto;
243 
244 #ifdef SMP
245 	/*
246 	 * We really want to shutdown on the BSP.  Subsystems such as ACPI
247 	 * can't power-down the box otherwise.
248 	 */
249 	if (smp_active_mask > 1) {
250 		printf("boot() called on cpu#%d\n", mycpu->gd_cpuid);
251 	}
252 	if (panicstr == NULL && mycpu->gd_cpuid != 0) {
253 		printf("Switching to cpu #0 for shutdown\n");
254 		lwkt_setcpu_self(globaldata_find(0));
255 	}
256 #endif
257 	/*
258 	 * Do any callouts that should be done BEFORE syncing the filesystems.
259 	 */
260 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
261 
262 	/*
263 	 * Now sync filesystems
264 	 */
265 	if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
266 		struct buf *bp;
267 		int iter, nbusy, pbusy;
268 
269 		waittime = 0;
270 		printf("\nsyncing disks... ");
271 
272 		sync(NULL);	/* YYY was sync(&proc0, NULL). why proc0 ? */
273 
274 		/*
275 		 * With soft updates, some buffers that are
276 		 * written will be remarked as dirty until other
277 		 * buffers are written.
278 		 */
279 		for (iter = pbusy = 0; iter < 20; iter++) {
280 			nbusy = 0;
281 			for (bp = &buf[nbuf]; --bp >= buf; ) {
282 				if ((bp->b_flags & B_INVAL) == 0 &&
283 				    BUF_REFCNT(bp) > 0) {
284 					nbusy++;
285 				} else if ((bp->b_flags & (B_DELWRI | B_INVAL))
286 						== B_DELWRI) {
287 					/* bawrite(bp);*/
288 					nbusy++;
289 				}
290 			}
291 			if (nbusy == 0)
292 				break;
293 			printf("%d ", nbusy);
294 			if (nbusy < pbusy)
295 				iter = 0;
296 			pbusy = nbusy;
297 			/*
298 			 * XXX:
299 			 * Process soft update work queue if buffers don't sync
300 			 * after 6 iterations by permitting the syncer to run.
301 			 */
302 			if (iter > 5 && bioops.io_sync)
303 				(*bioops.io_sync)(NULL);
304 			sync(NULL); /* YYY was sync(&proc0, NULL). why proc0 ? */
305 			tsleep(boot, 0, "shutdn", hz * iter / 20 + 1);
306 		}
307 		printf("\n");
308 		/*
309 		 * Count only busy local buffers to prevent forcing
310 		 * a fsck if we're just a client of a wedged NFS server
311 		 */
312 		nbusy = 0;
313 		for (bp = &buf[nbuf]; --bp >= buf; ) {
314 			if (((bp->b_flags&B_INVAL) == 0 && BUF_REFCNT(bp)) ||
315 			    ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
316 				/*
317 				 * Only count buffers undergoing write I/O
318 				 * on the related vnode.
319 				 */
320 				if (bp->b_vp == NULL ||
321 				    bp->b_vp->v_track_write.bk_active == 0) {
322 					continue;
323 				}
324 				nbusy++;
325 #if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
326 				printf(
327 			    "%p %d: dev:?, flags:%08lx, blkno:%ld, lblkno:%ld\n",
328 				    bp, nbusy,
329 				    bp->b_flags, (long)bp->b_bio1.bio_blkno,
330 				    (long)bp->b_lblkno);
331 #endif
332 			}
333 		}
334 		if (nbusy) {
335 			/*
336 			 * Failed to sync all blocks. Indicate this and don't
337 			 * unmount filesystems (thus forcing an fsck on reboot).
338 			 */
339 			printf("giving up on %d buffers\n", nbusy);
340 #ifdef DDB
341 			Debugger("busy buffer problem");
342 #endif /* DDB */
343 			tsleep(boot, 0, "shutdn", hz * 5 + 1);
344 		} else {
345 			printf("done\n");
346 			/*
347 			 * Unmount filesystems
348 			 */
349 			if (panicstr == 0)
350 				vfs_unmountall();
351 		}
352 		tsleep(boot, 0, "shutdn", hz / 10 + 1);
353 	}
354 
355 	print_uptime();
356 
357 	/*
358 	 * Ok, now do things that assume all filesystem activity has
359 	 * been completed.
360 	 */
361 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
362 	crit_enter();
363 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold)
364 		dumpsys();
365 
366 	/* Now that we're going to really halt the system... */
367 	EVENTHANDLER_INVOKE(shutdown_final, howto);
368 
369 	for(;;) ;	/* safety against shutdown_reset not working */
370 	/* NOTREACHED */
371 }
372 
373 /*
374  * If the shutdown was a clean halt, behave accordingly.
375  */
376 static void
377 shutdown_halt(void *junk, int howto)
378 {
379 	if (howto & RB_HALT) {
380 		printf("\n");
381 		printf("The operating system has halted.\n");
382 		printf("Please press any key to reboot.\n\n");
383 		switch (cngetc()) {
384 		case -1:		/* No console, just die */
385 			cpu_halt();
386 			/* NOTREACHED */
387 		default:
388 			howto &= ~RB_HALT;
389 			break;
390 		}
391 	}
392 }
393 
394 /*
395  * Check to see if the system paniced, pause and then reboot
396  * according to the specified delay.
397  */
398 static void
399 shutdown_panic(void *junk, int howto)
400 {
401 	int loop;
402 
403 	if (howto & RB_DUMP) {
404 		if (PANIC_REBOOT_WAIT_TIME != 0) {
405 			if (PANIC_REBOOT_WAIT_TIME != -1) {
406 				printf("Automatic reboot in %d seconds - "
407 				       "press a key on the console to abort\n",
408 					PANIC_REBOOT_WAIT_TIME);
409 				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
410 				     loop > 0; --loop) {
411 					DELAY(1000 * 100); /* 1/10th second */
412 					/* Did user type a key? */
413 					if (cncheckc() != -1)
414 						break;
415 				}
416 				if (!loop)
417 					return;
418 			}
419 		} else { /* zero time specified - reboot NOW */
420 			return;
421 		}
422 		printf("--> Press a key on the console to reboot,\n");
423 		printf("--> or switch off the system now.\n");
424 		cngetc();
425 	}
426 }
427 
428 /*
429  * Everything done, now reset
430  */
431 static void
432 shutdown_reset(void *junk, int howto)
433 {
434 	printf("Rebooting...\n");
435 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
436 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
437 	cpu_reset();
438 	/* NOTREACHED */ /* assuming reset worked */
439 }
440 
441 /*
442  * Magic number for savecore
443  *
444  * exported (symorder) and used at least by savecore(8)
445  *
446  */
447 static u_long const	dumpmag = 0x8fca0101UL;
448 
449 static int	dumpsize = 0;		/* also for savecore */
450 
451 static int	dodump = 1;
452 
453 SYSCTL_INT(_machdep, OID_AUTO, do_dump, CTLFLAG_RW, &dodump, 0,
454     "Try to perform coredump on kernel panic");
455 
456 static int
457 setdumpdev(dev)
458 	dev_t dev;
459 {
460 	int psize;
461 	long newdumplo;
462 
463 	if (dev == NODEV) {
464 		dumpdev = dev;
465 		return (0);
466 	}
467 	psize = dev_dpsize(dev);
468 	if (psize == -1)
469 		return (ENXIO);
470 	/*
471 	 * XXX should clean up checking in dumpsys() to be more like this.
472 	 */
473 	newdumplo = psize - Maxmem * (PAGE_SIZE / DEV_BSIZE);
474 	if (newdumplo <= LABELSECTOR)
475 		return (ENOSPC);
476 	dumpdev = dev;
477 	dumplo = newdumplo;
478 	return (0);
479 }
480 
481 
482 /* ARGSUSED */
483 static void dump_conf (void *dummy);
484 static void
485 dump_conf(dummy)
486 	void *dummy;
487 {
488 	char *path;
489 	dev_t dev;
490 
491 	path = malloc(MNAMELEN, M_TEMP, M_WAITOK);
492 	if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
493 		dev = getdiskbyname(path);
494 		if (dev != NODEV)
495 			dumpdev = dev;
496 	}
497 	free(path, M_TEMP);
498 	if (setdumpdev(dumpdev) != 0)
499 		dumpdev = NODEV;
500 }
501 
502 SYSINIT(dump_conf, SI_SUB_DUMP_CONF, SI_ORDER_FIRST, dump_conf, NULL)
503 
504 static int
505 sysctl_kern_dumpdev(SYSCTL_HANDLER_ARGS)
506 {
507 	int error;
508 	udev_t ndumpdev;
509 
510 	ndumpdev = dev2udev(dumpdev);
511 	error = sysctl_handle_opaque(oidp, &ndumpdev, sizeof ndumpdev, req);
512 	if (error == 0 && req->newptr != NULL)
513 		error = setdumpdev(udev2dev(ndumpdev, 0));
514 	return (error);
515 }
516 
517 SYSCTL_PROC(_kern, KERN_DUMPDEV, dumpdev, CTLTYPE_OPAQUE|CTLFLAG_RW,
518 	0, sizeof dumpdev, sysctl_kern_dumpdev, "T,dev_t", "");
519 
520 /*
521  * Doadump comes here after turning off memory management and
522  * getting on the dump stack, either when called above, or by
523  * the auto-restart code.
524  */
525 static void
526 dumpsys(void)
527 {
528 	int	error;
529 
530 	savectx(&dumppcb);
531 	if (dumping++) {
532 		printf("Dump already in progress, bailing...\n");
533 		return;
534 	}
535 	if (!dodump)
536 		return;
537 	if (dumpdev == NODEV)
538 		return;
539 	dumpsize = Maxmem;
540 	printf("\ndumping to dev %s, offset %ld\n", devtoname(dumpdev), dumplo);
541 	printf("dump ");
542 	error = dev_ddump(dumpdev);
543 	if (error == 0) {
544 		printf("succeeded\n");
545 		return;
546 	}
547 	printf("failed, reason: ");
548 	switch (error) {
549 	case ENOSYS:
550 	case ENODEV:
551 		printf("device doesn't support a dump routine\n");
552 		break;
553 
554 	case ENXIO:
555 		printf("device bad\n");
556 		break;
557 
558 	case EFAULT:
559 		printf("device not ready\n");
560 		break;
561 
562 	case EINVAL:
563 		printf("area improper\n");
564 		break;
565 
566 	case EIO:
567 		printf("i/o error\n");
568 		break;
569 
570 	case EINTR:
571 		printf("aborted from console\n");
572 		break;
573 
574 	default:
575 		printf("unknown, error = %d\n", error);
576 		break;
577 	}
578 }
579 
580 int
581 dumpstatus(vm_offset_t addr, off_t count)
582 {
583 	int c;
584 
585 	if (addr % (1024 * 1024) == 0) {
586 #ifdef HW_WDOG
587 		if (wdog_tickler)
588 			(*wdog_tickler)();
589 #endif
590 		printf("%ld ", (long)(count / (1024 * 1024)));
591 	}
592 
593 	if ((c = cncheckc()) == 0x03)
594 		return -1;
595 	else if (c != -1)
596 		printf("[CTRL-C to abort] ");
597 
598 	return 0;
599 }
600 
601 /*
602  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
603  * and then reboots.  If we are called twice, then we avoid trying to sync
604  * the disks as this often leads to recursive panics.
605  */
606 void
607 panic(const char *fmt, ...)
608 {
609 	int bootopt, newpanic;
610 	__va_list ap;
611 	static char buf[256];
612 
613 #ifdef SMP
614 	/*
615 	 * If a panic occurs on multiple cpus before the first is able to
616 	 * halt the other cpus, only one cpu is allowed to take the panic.
617 	 * Attempt to be verbose about this situation but if the printf()
618 	 * itself panics don't let us overrun the kernel stack.
619 	 *
620 	 * Be very nasty about descheduling our thread at the lowest
621 	 * level possible in an attempt to freeze the thread without
622 	 * inducing further panics.
623 	 *
624 	 * Bumping gd_trap_nesting_level will also bypass assertions in
625 	 * lwkt_switch() and allow us to switch away even if we are a
626 	 * FAST interrupt or IPI.
627 	 */
628 	if (atomic_poll_acquire_int(&panic_cpu_interlock)) {
629 		panic_cpu_gd = mycpu;
630 	} else if (panic_cpu_gd != mycpu) {
631 		crit_enter();
632 		++mycpu->gd_trap_nesting_level;
633 		if (mycpu->gd_trap_nesting_level < 25) {
634 			printf("SECONDARY PANIC ON CPU %d THREAD %p\n",
635 				mycpu->gd_cpuid, curthread);
636 		}
637 		curthread->td_release = NULL;	/* be a grinch */
638 		for (;;) {
639 			lwkt_deschedule_self(curthread);
640 			lwkt_switch();
641 		}
642 		/* NOT REACHED */
643 		/* --mycpu->gd_trap_nesting_level */
644 		/* crit_exit() */
645 	}
646 #endif
647 	bootopt = RB_AUTOBOOT | RB_DUMP;
648 	if (sync_on_panic == 0)
649 		bootopt |= RB_NOSYNC;
650 	newpanic = 0;
651 	if (panicstr)
652 		bootopt |= RB_NOSYNC;
653 	else {
654 		panicstr = fmt;
655 		newpanic = 1;
656 	}
657 
658 	__va_start(ap, fmt);
659 	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
660 	if (panicstr == fmt)
661 		panicstr = buf;
662 	__va_end(ap);
663 	printf("panic: %s\n", buf);
664 #ifdef SMP
665 	/* three separate prints in case of an unmapped page and trap */
666 	printf("mp_lock = %08x; ", mp_lock);
667 	printf("cpuid = %d; ", mycpu->gd_cpuid);
668 	printf("lapic.id = %08x\n", lapic.id);
669 #endif
670 
671 #if defined(DDB)
672 	if (newpanic && trace_on_panic)
673 		db_print_backtrace();
674 	if (debugger_on_panic)
675 		Debugger ("panic");
676 #endif
677 	boot(bootopt);
678 }
679 
680 /*
681  * Support for poweroff delay.
682  */
683 #ifndef POWEROFF_DELAY
684 # define POWEROFF_DELAY 5000
685 #endif
686 static int poweroff_delay = POWEROFF_DELAY;
687 
688 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
689 	&poweroff_delay, 0, "");
690 
691 static void
692 poweroff_wait(void *junk, int howto)
693 {
694 	if(!(howto & RB_POWEROFF) || poweroff_delay <= 0)
695 		return;
696 	DELAY(poweroff_delay * 1000);
697 }
698 
699 /*
700  * Some system processes (e.g. syncer) need to be stopped at appropriate
701  * points in their main loops prior to a system shutdown, so that they
702  * won't interfere with the shutdown process (e.g. by holding a disk buf
703  * to cause sync to fail).  For each of these system processes, register
704  * shutdown_kproc() as a handler for one of shutdown events.
705  */
706 static int kproc_shutdown_wait = 60;
707 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
708     &kproc_shutdown_wait, 0, "");
709 
710 void
711 shutdown_kproc(void *arg, int howto)
712 {
713 	struct thread *td;
714 	struct proc *p;
715 	int error;
716 
717 	if (panicstr)
718 		return;
719 
720 	td = (struct thread *)arg;
721 	if ((p = td->td_proc) != NULL) {
722 	    printf("Waiting (max %d seconds) for system process `%s' to stop...",
723 		kproc_shutdown_wait, p->p_comm);
724 	} else {
725 	    printf("Waiting (max %d seconds) for system thread %s to stop...",
726 		kproc_shutdown_wait, td->td_comm);
727 	}
728 	error = suspend_kproc(td, kproc_shutdown_wait * hz);
729 
730 	if (error == EWOULDBLOCK)
731 		printf("timed out\n");
732 	else
733 		printf("stopped\n");
734 }
735