xref: /dragonfly/sys/kern/kern_shutdown.c (revision fe76c4fb)
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 1.30 2006/06/05 07:26:10 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 static int shutdown_busycount1(struct buf *bp, void *info);
146 static int shutdown_busycount2(struct buf *bp, void *info);
147 
148 /* register various local shutdown events */
149 static void
150 shutdown_conf(void *unused)
151 {
152 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL, SHUTDOWN_PRI_FIRST);
153 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL, SHUTDOWN_PRI_LAST + 100);
154 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL, SHUTDOWN_PRI_LAST + 100);
155 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL, SHUTDOWN_PRI_LAST + 200);
156 }
157 
158 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL)
159 
160 /* ARGSUSED */
161 
162 /*
163  * The system call that results in a reboot
164  */
165 int
166 sys_reboot(struct reboot_args *uap)
167 {
168 	struct thread *td = curthread;
169 	int error;
170 
171 	if ((error = suser(td)))
172 		return (error);
173 
174 	boot(uap->opt);
175 	return (0);
176 }
177 
178 /*
179  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
180  */
181 static int shutdown_howto = 0;
182 
183 void
184 shutdown_nice(int howto)
185 {
186 	shutdown_howto = howto;
187 
188 	/* Send a signal to init(8) and have it shutdown the world */
189 	if (initproc != NULL) {
190 		psignal(initproc, SIGINT);
191 	} else {
192 		/* No init(8) running, so simply reboot */
193 		boot(RB_NOSYNC);
194 	}
195 	return;
196 }
197 static int	waittime = -1;
198 static struct thread *dumpthread;
199 static struct pcb dumppcb;
200 
201 static void
202 print_uptime()
203 {
204 	int f;
205 	struct timespec ts;
206 
207 	getnanouptime(&ts);
208 	printf("Uptime: ");
209 	f = 0;
210 	if (ts.tv_sec >= 86400) {
211 		printf("%ldd", ts.tv_sec / 86400);
212 		ts.tv_sec %= 86400;
213 		f = 1;
214 	}
215 	if (f || ts.tv_sec >= 3600) {
216 		printf("%ldh", ts.tv_sec / 3600);
217 		ts.tv_sec %= 3600;
218 		f = 1;
219 	}
220 	if (f || ts.tv_sec >= 60) {
221 		printf("%ldm", ts.tv_sec / 60);
222 		ts.tv_sec %= 60;
223 		f = 1;
224 	}
225 	printf("%lds\n", ts.tv_sec);
226 }
227 
228 /*
229  *  Go through the rigmarole of shutting down..
230  * this used to be in machdep.c but I'll be dammned if I could see
231  * anything machine dependant in it.
232  */
233 static void
234 boot(int howto)
235 {
236 	/*
237 	 * Get rid of any user scheduler baggage and then give
238 	 * us a high priority.
239 	 */
240 	if (curthread->td_release)
241 		curthread->td_release(curthread);
242 	lwkt_setpri_self(TDPRI_MAX);
243 
244 	/* collect extra flags that shutdown_nice might have set */
245 	howto |= shutdown_howto;
246 
247 #ifdef SMP
248 	/*
249 	 * We really want to shutdown on the BSP.  Subsystems such as ACPI
250 	 * can't power-down the box otherwise.
251 	 */
252 	if (smp_active_mask > 1) {
253 		printf("boot() called on cpu#%d\n", mycpu->gd_cpuid);
254 	}
255 	if (panicstr == NULL && mycpu->gd_cpuid != 0) {
256 		printf("Switching to cpu #0 for shutdown\n");
257 		lwkt_setcpu_self(globaldata_find(0));
258 	}
259 #endif
260 	/*
261 	 * Do any callouts that should be done BEFORE syncing the filesystems.
262 	 */
263 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
264 
265 	/*
266 	 * Now sync filesystems
267 	 */
268 	if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
269 		int iter, nbusy, pbusy;
270 
271 		waittime = 0;
272 		printf("\nsyncing disks... ");
273 
274 		sys_sync(NULL);	/* YYY was sync(&proc0, NULL). why proc0 ? */
275 
276 		/*
277 		 * With soft updates, some buffers that are
278 		 * written will be remarked as dirty until other
279 		 * buffers are written.
280 		 */
281 		for (iter = pbusy = 0; iter < 20; iter++) {
282 			nbusy = scan_all_buffers(shutdown_busycount1, NULL);
283 			if (nbusy == 0)
284 				break;
285 			printf("%d ", nbusy);
286 			if (nbusy < pbusy)
287 				iter = 0;
288 			pbusy = nbusy;
289 			/*
290 			 * XXX:
291 			 * Process soft update work queue if buffers don't sync
292 			 * after 6 iterations by permitting the syncer to run.
293 			 */
294 			if (iter > 5 && bioops.io_sync)
295 				(*bioops.io_sync)(NULL);
296 			sys_sync(NULL); /* YYY was sync(&proc0, NULL). why proc0 ? */
297 			tsleep(boot, 0, "shutdn", hz * iter / 20 + 1);
298 		}
299 		printf("\n");
300 		/*
301 		 * Count only busy local buffers to prevent forcing
302 		 * a fsck if we're just a client of a wedged NFS server
303 		 */
304 		nbusy = scan_all_buffers(shutdown_busycount2, NULL);
305 		if (nbusy) {
306 			/*
307 			 * Failed to sync all blocks. Indicate this and don't
308 			 * unmount filesystems (thus forcing an fsck on reboot).
309 			 */
310 			printf("giving up on %d buffers\n", nbusy);
311 #ifdef DDB
312 			Debugger("busy buffer problem");
313 #endif /* DDB */
314 			tsleep(boot, 0, "shutdn", hz * 5 + 1);
315 		} else {
316 			printf("done\n");
317 			/*
318 			 * Unmount filesystems
319 			 */
320 			if (panicstr == 0)
321 				vfs_unmountall();
322 		}
323 		tsleep(boot, 0, "shutdn", hz / 10 + 1);
324 	}
325 
326 	print_uptime();
327 
328 	/*
329 	 * Ok, now do things that assume all filesystem activity has
330 	 * been completed.
331 	 */
332 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
333 	crit_enter();
334 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold)
335 		dumpsys();
336 
337 	/* Now that we're going to really halt the system... */
338 	EVENTHANDLER_INVOKE(shutdown_final, howto);
339 
340 	for(;;) ;	/* safety against shutdown_reset not working */
341 	/* NOTREACHED */
342 }
343 
344 static int
345 shutdown_busycount1(struct buf *bp, void *info)
346 {
347 	if ((bp->b_flags & B_INVAL) == 0 && BUF_REFCNT(bp) > 0)
348 		return(1);
349 	if ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI)
350 		return (1);
351 	return (0);
352 }
353 
354 static int
355 shutdown_busycount2(struct buf *bp, void *info)
356 {
357 	if (((bp->b_flags & B_INVAL) == 0 && BUF_REFCNT(bp)) ||
358 	    ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
359 		/*
360 		 * Only count buffers undergoing write I/O
361 		 * on the related vnode.
362 		 */
363 		if (bp->b_vp == NULL ||
364 		    bp->b_vp->v_track_write.bk_active == 0) {
365 			return (0);
366 		}
367 #if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
368 		printf(
369 	    "%p dev:?, flags:%08lx, loffset:%lld, doffset:%lld\n",
370 		    bp,
371 		    bp->b_flags, bp->b_loffset,
372 		    bp->b_bio2.bio_offset);
373 #endif
374 		return(1);
375 	}
376 	return(0);
377 }
378 
379 /*
380  * If the shutdown was a clean halt, behave accordingly.
381  */
382 static void
383 shutdown_halt(void *junk, int howto)
384 {
385 	if (howto & RB_HALT) {
386 		printf("\n");
387 		printf("The operating system has halted.\n");
388 		printf("Please press any key to reboot.\n\n");
389 		switch (cngetc()) {
390 		case -1:		/* No console, just die */
391 			cpu_halt();
392 			/* NOTREACHED */
393 		default:
394 			howto &= ~RB_HALT;
395 			break;
396 		}
397 	}
398 }
399 
400 /*
401  * Check to see if the system paniced, pause and then reboot
402  * according to the specified delay.
403  */
404 static void
405 shutdown_panic(void *junk, int howto)
406 {
407 	int loop;
408 
409 	if (howto & RB_DUMP) {
410 		if (PANIC_REBOOT_WAIT_TIME != 0) {
411 			if (PANIC_REBOOT_WAIT_TIME != -1) {
412 				printf("Automatic reboot in %d seconds - "
413 				       "press a key on the console to abort\n",
414 					PANIC_REBOOT_WAIT_TIME);
415 				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
416 				     loop > 0; --loop) {
417 					DELAY(1000 * 100); /* 1/10th second */
418 					/* Did user type a key? */
419 					if (cncheckc() != -1)
420 						break;
421 				}
422 				if (!loop)
423 					return;
424 			}
425 		} else { /* zero time specified - reboot NOW */
426 			return;
427 		}
428 		printf("--> Press a key on the console to reboot,\n");
429 		printf("--> or switch off the system now.\n");
430 		cngetc();
431 	}
432 }
433 
434 /*
435  * Everything done, now reset
436  */
437 static void
438 shutdown_reset(void *junk, int howto)
439 {
440 	printf("Rebooting...\n");
441 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
442 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
443 	cpu_reset();
444 	/* NOTREACHED */ /* assuming reset worked */
445 }
446 
447 /*
448  * Magic number for savecore
449  *
450  * exported (symorder) and used at least by savecore(8)
451  *
452  */
453 static u_long const	dumpmag = 0x8fca0101UL;
454 
455 static int	dumpsize = 0;		/* also for savecore */
456 
457 static int	dodump = 1;
458 
459 SYSCTL_INT(_machdep, OID_AUTO, do_dump, CTLFLAG_RW, &dodump, 0,
460     "Try to perform coredump on kernel panic");
461 
462 static int
463 setdumpdev(dev)
464 	dev_t dev;
465 {
466 	int psize;
467 	long newdumplo;
468 
469 	if (dev == NODEV) {
470 		dumpdev = dev;
471 		return (0);
472 	}
473 	psize = dev_dpsize(dev);
474 	if (psize == -1)
475 		return (ENXIO);
476 	/*
477 	 * XXX should clean up checking in dumpsys() to be more like this.
478 	 */
479 	newdumplo = psize - Maxmem * (PAGE_SIZE / DEV_BSIZE);
480 	if (newdumplo <= LABELSECTOR)
481 		return (ENOSPC);
482 	dumpdev = dev;
483 	dumplo = newdumplo;
484 	return (0);
485 }
486 
487 
488 /* ARGSUSED */
489 static void dump_conf (void *dummy);
490 static void
491 dump_conf(dummy)
492 	void *dummy;
493 {
494 	char *path;
495 	dev_t dev;
496 
497 	path = malloc(MNAMELEN, M_TEMP, M_WAITOK);
498 	if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
499 		dev = getdiskbyname(path);
500 		if (dev != NODEV)
501 			dumpdev = dev;
502 	}
503 	free(path, M_TEMP);
504 	if (setdumpdev(dumpdev) != 0)
505 		dumpdev = NODEV;
506 }
507 
508 SYSINIT(dump_conf, SI_SUB_DUMP_CONF, SI_ORDER_FIRST, dump_conf, NULL)
509 
510 static int
511 sysctl_kern_dumpdev(SYSCTL_HANDLER_ARGS)
512 {
513 	int error;
514 	udev_t ndumpdev;
515 
516 	ndumpdev = dev2udev(dumpdev);
517 	error = sysctl_handle_opaque(oidp, &ndumpdev, sizeof ndumpdev, req);
518 	if (error == 0 && req->newptr != NULL)
519 		error = setdumpdev(udev2dev(ndumpdev, 0));
520 	return (error);
521 }
522 
523 SYSCTL_PROC(_kern, KERN_DUMPDEV, dumpdev, CTLTYPE_OPAQUE|CTLFLAG_RW,
524 	0, sizeof dumpdev, sysctl_kern_dumpdev, "T,dev_t", "");
525 
526 /*
527  * Doadump comes here after turning off memory management and
528  * getting on the dump stack, either when called above, or by
529  * the auto-restart code.
530  */
531 static void
532 dumpsys(void)
533 {
534 	int	error;
535 
536 	savectx(&dumppcb);
537 	dumpthread = curthread;
538 	if (dumping++) {
539 		printf("Dump already in progress, bailing...\n");
540 		return;
541 	}
542 	if (!dodump)
543 		return;
544 	if (dumpdev == NODEV)
545 		return;
546 	dumpsize = Maxmem;
547 	printf("\ndumping to dev %s, offset %ld\n", devtoname(dumpdev), dumplo);
548 	printf("dump ");
549 	error = dev_ddump(dumpdev);
550 	if (error == 0) {
551 		printf("succeeded\n");
552 		return;
553 	}
554 	printf("failed, reason: ");
555 	switch (error) {
556 	case ENOSYS:
557 	case ENODEV:
558 		printf("device doesn't support a dump routine\n");
559 		break;
560 
561 	case ENXIO:
562 		printf("device bad\n");
563 		break;
564 
565 	case EFAULT:
566 		printf("device not ready\n");
567 		break;
568 
569 	case EINVAL:
570 		printf("area improper\n");
571 		break;
572 
573 	case EIO:
574 		printf("i/o error\n");
575 		break;
576 
577 	case EINTR:
578 		printf("aborted from console\n");
579 		break;
580 
581 	default:
582 		printf("unknown, error = %d\n", error);
583 		break;
584 	}
585 }
586 
587 int
588 dumpstatus(vm_offset_t addr, off_t count)
589 {
590 	int c;
591 
592 	if (addr % (1024 * 1024) == 0) {
593 #ifdef HW_WDOG
594 		if (wdog_tickler)
595 			(*wdog_tickler)();
596 #endif
597 		printf("%ld ", (long)(count / (1024 * 1024)));
598 	}
599 
600 	if ((c = cncheckc()) == 0x03)
601 		return -1;
602 	else if (c != -1)
603 		printf("[CTRL-C to abort] ");
604 
605 	return 0;
606 }
607 
608 /*
609  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
610  * and then reboots.  If we are called twice, then we avoid trying to sync
611  * the disks as this often leads to recursive panics.
612  */
613 void
614 panic(const char *fmt, ...)
615 {
616 	int bootopt, newpanic;
617 	__va_list ap;
618 	static char buf[256];
619 
620 #ifdef SMP
621 	/*
622 	 * If a panic occurs on multiple cpus before the first is able to
623 	 * halt the other cpus, only one cpu is allowed to take the panic.
624 	 * Attempt to be verbose about this situation but if the printf()
625 	 * itself panics don't let us overrun the kernel stack.
626 	 *
627 	 * Be very nasty about descheduling our thread at the lowest
628 	 * level possible in an attempt to freeze the thread without
629 	 * inducing further panics.
630 	 *
631 	 * Bumping gd_trap_nesting_level will also bypass assertions in
632 	 * lwkt_switch() and allow us to switch away even if we are a
633 	 * FAST interrupt or IPI.
634 	 */
635 	if (atomic_poll_acquire_int(&panic_cpu_interlock)) {
636 		panic_cpu_gd = mycpu;
637 	} else if (panic_cpu_gd != mycpu) {
638 		crit_enter();
639 		++mycpu->gd_trap_nesting_level;
640 		if (mycpu->gd_trap_nesting_level < 25) {
641 			printf("SECONDARY PANIC ON CPU %d THREAD %p\n",
642 				mycpu->gd_cpuid, curthread);
643 		}
644 		curthread->td_release = NULL;	/* be a grinch */
645 		for (;;) {
646 			lwkt_deschedule_self(curthread);
647 			lwkt_switch();
648 		}
649 		/* NOT REACHED */
650 		/* --mycpu->gd_trap_nesting_level */
651 		/* crit_exit() */
652 	}
653 #endif
654 	bootopt = RB_AUTOBOOT | RB_DUMP;
655 	if (sync_on_panic == 0)
656 		bootopt |= RB_NOSYNC;
657 	newpanic = 0;
658 	if (panicstr)
659 		bootopt |= RB_NOSYNC;
660 	else {
661 		panicstr = fmt;
662 		newpanic = 1;
663 	}
664 
665 	__va_start(ap, fmt);
666 	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
667 	if (panicstr == fmt)
668 		panicstr = buf;
669 	__va_end(ap);
670 	printf("panic: %s\n", buf);
671 #ifdef SMP
672 	/* three separate prints in case of an unmapped page and trap */
673 	printf("mp_lock = %08x; ", mp_lock);
674 	printf("cpuid = %d; ", mycpu->gd_cpuid);
675 	printf("lapic.id = %08x\n", lapic.id);
676 #endif
677 
678 #if defined(DDB)
679 	if (newpanic && trace_on_panic)
680 		db_print_backtrace();
681 	if (debugger_on_panic)
682 		Debugger ("panic");
683 #endif
684 	boot(bootopt);
685 }
686 
687 /*
688  * Support for poweroff delay.
689  */
690 #ifndef POWEROFF_DELAY
691 # define POWEROFF_DELAY 5000
692 #endif
693 static int poweroff_delay = POWEROFF_DELAY;
694 
695 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
696 	&poweroff_delay, 0, "");
697 
698 static void
699 poweroff_wait(void *junk, int howto)
700 {
701 	if(!(howto & RB_POWEROFF) || poweroff_delay <= 0)
702 		return;
703 	DELAY(poweroff_delay * 1000);
704 }
705 
706 /*
707  * Some system processes (e.g. syncer) need to be stopped at appropriate
708  * points in their main loops prior to a system shutdown, so that they
709  * won't interfere with the shutdown process (e.g. by holding a disk buf
710  * to cause sync to fail).  For each of these system processes, register
711  * shutdown_kproc() as a handler for one of shutdown events.
712  */
713 static int kproc_shutdown_wait = 60;
714 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
715     &kproc_shutdown_wait, 0, "");
716 
717 void
718 shutdown_kproc(void *arg, int howto)
719 {
720 	struct thread *td;
721 	struct proc *p;
722 	int error;
723 
724 	if (panicstr)
725 		return;
726 
727 	td = (struct thread *)arg;
728 	if ((p = td->td_proc) != NULL) {
729 	    printf("Waiting (max %d seconds) for system process `%s' to stop...",
730 		kproc_shutdown_wait, p->p_comm);
731 	} else {
732 	    printf("Waiting (max %d seconds) for system thread %s to stop...",
733 		kproc_shutdown_wait, td->td_comm);
734 	}
735 	error = suspend_kproc(td, kproc_shutdown_wait * hz);
736 
737 	if (error == EWOULDBLOCK)
738 		printf("timed out\n");
739 	else
740 		printf("stopped\n");
741 }
742