xref: /freebsd/sys/kern/kern_shutdown.c (revision 3e65b9c6e6b7b2081d54e1dc40983c3c00eaf738)
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  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)kern_shutdown.c	8.3 (Berkeley) 1/21/94
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "opt_ddb.h"
41 #include "opt_kdb.h"
42 #include "opt_panic.h"
43 #include "opt_sched.h"
44 #include "opt_watchdog.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/bio.h>
49 #include <sys/buf.h>
50 #include <sys/conf.h>
51 #include <sys/cons.h>
52 #include <sys/eventhandler.h>
53 #include <sys/jail.h>
54 #include <sys/kdb.h>
55 #include <sys/kernel.h>
56 #include <sys/kerneldump.h>
57 #include <sys/kthread.h>
58 #include <sys/malloc.h>
59 #include <sys/mount.h>
60 #include <sys/priv.h>
61 #include <sys/proc.h>
62 #include <sys/reboot.h>
63 #include <sys/resourcevar.h>
64 #include <sys/sched.h>
65 #include <sys/smp.h>
66 #include <sys/sysctl.h>
67 #include <sys/sysproto.h>
68 #include <sys/vnode.h>
69 #ifdef SW_WATCHDOG
70 #include <sys/watchdog.h>
71 #endif
72 
73 #include <ddb/ddb.h>
74 
75 #include <machine/cpu.h>
76 #include <machine/pcb.h>
77 #include <machine/smp.h>
78 
79 #include <security/mac/mac_framework.h>
80 
81 #include <vm/vm.h>
82 #include <vm/vm_object.h>
83 #include <vm/vm_page.h>
84 #include <vm/vm_pager.h>
85 #include <vm/swap_pager.h>
86 
87 #include <sys/signalvar.h>
88 
89 #ifndef PANIC_REBOOT_WAIT_TIME
90 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
91 #endif
92 
93 /*
94  * Note that stdarg.h and the ANSI style va_start macro is used for both
95  * ANSI and traditional C compilers.
96  */
97 #include <machine/stdarg.h>
98 
99 #ifdef KDB
100 #ifdef KDB_UNATTENDED
101 int debugger_on_panic = 0;
102 #else
103 int debugger_on_panic = 1;
104 #endif
105 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
106     CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_TUN,
107     &debugger_on_panic, 0, "Run debugger on kernel panic");
108 TUNABLE_INT("debug.debugger_on_panic", &debugger_on_panic);
109 
110 #ifdef KDB_TRACE
111 static int trace_on_panic = 1;
112 #else
113 static int trace_on_panic = 0;
114 #endif
115 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
116     CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_TUN,
117     &trace_on_panic, 0, "Print stack trace on kernel panic");
118 TUNABLE_INT("debug.trace_on_panic", &trace_on_panic);
119 #endif /* KDB */
120 
121 static int sync_on_panic = 0;
122 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
123 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
124 TUNABLE_INT("kern.sync_on_panic", &sync_on_panic);
125 
126 static int stop_scheduler_on_panic = 0;
127 SYSCTL_INT(_kern, OID_AUTO, stop_scheduler_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
128     &stop_scheduler_on_panic, 0, "stop scheduler upon entering panic");
129 TUNABLE_INT("kern.stop_scheduler_on_panic", &stop_scheduler_on_panic);
130 
131 static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
132     "Shutdown environment");
133 
134 #ifndef DIAGNOSTIC
135 static int show_busybufs;
136 #else
137 static int show_busybufs = 1;
138 #endif
139 SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
140 	&show_busybufs, 0, "");
141 
142 /*
143  * Variable panicstr contains argument to first call to panic; used as flag
144  * to indicate that the kernel has already called panic.
145  */
146 const char *panicstr;
147 
148 int stop_scheduler;			/* system stopped CPUs for panic */
149 int dumping;				/* system is dumping */
150 int rebooting;				/* system is rebooting */
151 static struct dumperinfo dumper;	/* our selected dumper */
152 
153 /* Context information for dump-debuggers. */
154 static struct pcb dumppcb;		/* Registers. */
155 static lwpid_t dumptid;			/* Thread ID. */
156 
157 static void poweroff_wait(void *, int);
158 static void shutdown_halt(void *junk, int howto);
159 static void shutdown_panic(void *junk, int howto);
160 static void shutdown_reset(void *junk, int howto);
161 
162 /* register various local shutdown events */
163 static void
164 shutdown_conf(void *unused)
165 {
166 
167 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
168 	    SHUTDOWN_PRI_FIRST);
169 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
170 	    SHUTDOWN_PRI_LAST + 100);
171 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
172 	    SHUTDOWN_PRI_LAST + 100);
173 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
174 	    SHUTDOWN_PRI_LAST + 200);
175 }
176 
177 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
178 
179 /*
180  * The system call that results in a reboot.
181  */
182 /* ARGSUSED */
183 int
184 sys_reboot(struct thread *td, struct reboot_args *uap)
185 {
186 	int error;
187 
188 	error = 0;
189 #ifdef MAC
190 	error = mac_system_check_reboot(td->td_ucred, uap->opt);
191 #endif
192 	if (error == 0)
193 		error = priv_check(td, PRIV_REBOOT);
194 	if (error == 0) {
195 		mtx_lock(&Giant);
196 		kern_reboot(uap->opt);
197 		mtx_unlock(&Giant);
198 	}
199 	return (error);
200 }
201 
202 /*
203  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
204  */
205 static int shutdown_howto = 0;
206 
207 void
208 shutdown_nice(int howto)
209 {
210 
211 	shutdown_howto = howto;
212 
213 	/* Send a signal to init(8) and have it shutdown the world */
214 	if (initproc != NULL) {
215 		PROC_LOCK(initproc);
216 		kern_psignal(initproc, SIGINT);
217 		PROC_UNLOCK(initproc);
218 	} else {
219 		/* No init(8) running, so simply reboot */
220 		kern_reboot(RB_NOSYNC);
221 	}
222 	return;
223 }
224 static int	waittime = -1;
225 
226 static void
227 print_uptime(void)
228 {
229 	int f;
230 	struct timespec ts;
231 
232 	getnanouptime(&ts);
233 	printf("Uptime: ");
234 	f = 0;
235 	if (ts.tv_sec >= 86400) {
236 		printf("%ldd", (long)ts.tv_sec / 86400);
237 		ts.tv_sec %= 86400;
238 		f = 1;
239 	}
240 	if (f || ts.tv_sec >= 3600) {
241 		printf("%ldh", (long)ts.tv_sec / 3600);
242 		ts.tv_sec %= 3600;
243 		f = 1;
244 	}
245 	if (f || ts.tv_sec >= 60) {
246 		printf("%ldm", (long)ts.tv_sec / 60);
247 		ts.tv_sec %= 60;
248 		f = 1;
249 	}
250 	printf("%lds\n", (long)ts.tv_sec);
251 }
252 
253 int
254 doadump(boolean_t textdump)
255 {
256 	boolean_t coredump;
257 
258 	if (dumping)
259 		return (EBUSY);
260 	if (dumper.dumper == NULL)
261 		return (ENXIO);
262 
263 	savectx(&dumppcb);
264 	dumptid = curthread->td_tid;
265 	dumping++;
266 
267 	coredump = TRUE;
268 #ifdef DDB
269 	if (textdump && textdump_pending) {
270 		coredump = FALSE;
271 		textdump_dumpsys(&dumper);
272 	}
273 #endif
274 	if (coredump)
275 		dumpsys(&dumper);
276 
277 	dumping--;
278 	return (0);
279 }
280 
281 static int
282 isbufbusy(struct buf *bp)
283 {
284 	if (((bp->b_flags & (B_INVAL | B_PERSISTENT)) == 0 &&
285 	    BUF_ISLOCKED(bp)) ||
286 	    ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI))
287 		return (1);
288 	return (0);
289 }
290 
291 /*
292  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
293  */
294 void
295 kern_reboot(int howto)
296 {
297 	static int first_buf_printf = 1;
298 
299 #if defined(SMP)
300 	/*
301 	 * Bind us to CPU 0 so that all shutdown code runs there.  Some
302 	 * systems don't shutdown properly (i.e., ACPI power off) if we
303 	 * run on another processor.
304 	 */
305 	if (!SCHEDULER_STOPPED()) {
306 		thread_lock(curthread);
307 		sched_bind(curthread, 0);
308 		thread_unlock(curthread);
309 		KASSERT(PCPU_GET(cpuid) == 0, ("boot: not running on cpu 0"));
310 	}
311 #endif
312 	/* We're in the process of rebooting. */
313 	rebooting = 1;
314 
315 	/* collect extra flags that shutdown_nice might have set */
316 	howto |= shutdown_howto;
317 
318 	/* We are out of the debugger now. */
319 	kdb_active = 0;
320 
321 	/*
322 	 * Do any callouts that should be done BEFORE syncing the filesystems.
323 	 */
324 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
325 
326 	/*
327 	 * Now sync filesystems
328 	 */
329 	if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
330 		register struct buf *bp;
331 		int iter, nbusy, pbusy;
332 #ifndef PREEMPTION
333 		int subiter;
334 #endif
335 
336 		waittime = 0;
337 
338 #ifdef SW_WATCHDOG
339 		wdog_kern_pat(WD_LASTVAL);
340 #endif
341 		sys_sync(curthread, NULL);
342 
343 		/*
344 		 * With soft updates, some buffers that are
345 		 * written will be remarked as dirty until other
346 		 * buffers are written.
347 		 */
348 		for (iter = pbusy = 0; iter < 20; iter++) {
349 			nbusy = 0;
350 			for (bp = &buf[nbuf]; --bp >= buf; )
351 				if (isbufbusy(bp))
352 					nbusy++;
353 			if (nbusy == 0) {
354 				if (first_buf_printf)
355 					printf("All buffers synced.");
356 				break;
357 			}
358 			if (first_buf_printf) {
359 				printf("Syncing disks, buffers remaining... ");
360 				first_buf_printf = 0;
361 			}
362 			printf("%d ", nbusy);
363 			if (nbusy < pbusy)
364 				iter = 0;
365 			pbusy = nbusy;
366 #ifdef SW_WATCHDOG
367 			wdog_kern_pat(WD_LASTVAL);
368 #endif
369 			sys_sync(curthread, NULL);
370 
371 #ifdef PREEMPTION
372 			/*
373 			 * Drop Giant and spin for a while to allow
374 			 * interrupt threads to run.
375 			 */
376 			DROP_GIANT();
377 			DELAY(50000 * iter);
378 			PICKUP_GIANT();
379 #else
380 			/*
381 			 * Drop Giant and context switch several times to
382 			 * allow interrupt threads to run.
383 			 */
384 			DROP_GIANT();
385 			for (subiter = 0; subiter < 50 * iter; subiter++) {
386 				thread_lock(curthread);
387 				mi_switch(SW_VOL, NULL);
388 				thread_unlock(curthread);
389 				DELAY(1000);
390 			}
391 			PICKUP_GIANT();
392 #endif
393 		}
394 		printf("\n");
395 		/*
396 		 * Count only busy local buffers to prevent forcing
397 		 * a fsck if we're just a client of a wedged NFS server
398 		 */
399 		nbusy = 0;
400 		for (bp = &buf[nbuf]; --bp >= buf; ) {
401 			if (isbufbusy(bp)) {
402 #if 0
403 /* XXX: This is bogus.  We should probably have a BO_REMOTE flag instead */
404 				if (bp->b_dev == NULL) {
405 					TAILQ_REMOVE(&mountlist,
406 					    bp->b_vp->v_mount, mnt_list);
407 					continue;
408 				}
409 #endif
410 				nbusy++;
411 				if (show_busybufs > 0) {
412 					printf(
413 	    "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:",
414 					    nbusy, bp, bp->b_vp, bp->b_flags,
415 					    (intmax_t)bp->b_blkno,
416 					    (intmax_t)bp->b_lblkno);
417 					BUF_LOCKPRINTINFO(bp);
418 					if (show_busybufs > 1)
419 						vn_printf(bp->b_vp,
420 						    "vnode content: ");
421 				}
422 			}
423 		}
424 		if (nbusy) {
425 			/*
426 			 * Failed to sync all blocks. Indicate this and don't
427 			 * unmount filesystems (thus forcing an fsck on reboot).
428 			 */
429 			printf("Giving up on %d buffers\n", nbusy);
430 			DELAY(5000000);	/* 5 seconds */
431 		} else {
432 			if (!first_buf_printf)
433 				printf("Final sync complete\n");
434 			/*
435 			 * Unmount filesystems
436 			 */
437 			if (panicstr == 0)
438 				vfs_unmountall();
439 		}
440 		swapoff_all();
441 		DELAY(100000);		/* wait for console output to finish */
442 	}
443 
444 	print_uptime();
445 
446 	cngrab();
447 
448 	/*
449 	 * Ok, now do things that assume all filesystem activity has
450 	 * been completed.
451 	 */
452 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
453 
454 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
455 		doadump(TRUE);
456 
457 	/* Now that we're going to really halt the system... */
458 	EVENTHANDLER_INVOKE(shutdown_final, howto);
459 
460 	for(;;) ;	/* safety against shutdown_reset not working */
461 	/* NOTREACHED */
462 }
463 
464 /*
465  * If the shutdown was a clean halt, behave accordingly.
466  */
467 static void
468 shutdown_halt(void *junk, int howto)
469 {
470 
471 	if (howto & RB_HALT) {
472 		printf("\n");
473 		printf("The operating system has halted.\n");
474 		printf("Please press any key to reboot.\n\n");
475 		switch (cngetc()) {
476 		case -1:		/* No console, just die */
477 			cpu_halt();
478 			/* NOTREACHED */
479 		default:
480 			howto &= ~RB_HALT;
481 			break;
482 		}
483 	}
484 }
485 
486 /*
487  * Check to see if the system paniced, pause and then reboot
488  * according to the specified delay.
489  */
490 static void
491 shutdown_panic(void *junk, int howto)
492 {
493 	int loop;
494 
495 	if (howto & RB_DUMP) {
496 		if (PANIC_REBOOT_WAIT_TIME != 0) {
497 			if (PANIC_REBOOT_WAIT_TIME != -1) {
498 				printf("Automatic reboot in %d seconds - "
499 				       "press a key on the console to abort\n",
500 					PANIC_REBOOT_WAIT_TIME);
501 				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
502 				     loop > 0; --loop) {
503 					DELAY(1000 * 100); /* 1/10th second */
504 					/* Did user type a key? */
505 					if (cncheckc() != -1)
506 						break;
507 				}
508 				if (!loop)
509 					return;
510 			}
511 		} else { /* zero time specified - reboot NOW */
512 			return;
513 		}
514 		printf("--> Press a key on the console to reboot,\n");
515 		printf("--> or switch off the system now.\n");
516 		cngetc();
517 	}
518 }
519 
520 /*
521  * Everything done, now reset
522  */
523 static void
524 shutdown_reset(void *junk, int howto)
525 {
526 
527 	printf("Rebooting...\n");
528 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
529 
530 	/*
531 	 * Acquiring smp_ipi_mtx here has a double effect:
532 	 * - it disables interrupts avoiding CPU0 preemption
533 	 *   by fast handlers (thus deadlocking  against other CPUs)
534 	 * - it avoids deadlocks against smp_rendezvous() or, more
535 	 *   generally, threads busy-waiting, with this spinlock held,
536 	 *   and waiting for responses by threads on other CPUs
537 	 *   (ie. smp_tlb_shootdown()).
538 	 *
539 	 * For the !SMP case it just needs to handle the former problem.
540 	 */
541 #ifdef SMP
542 	mtx_lock_spin(&smp_ipi_mtx);
543 #else
544 	spinlock_enter();
545 #endif
546 
547 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
548 	cpu_reset();
549 	/* NOTREACHED */ /* assuming reset worked */
550 }
551 
552 /*
553  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
554  * and then reboots.  If we are called twice, then we avoid trying to sync
555  * the disks as this often leads to recursive panics.
556  */
557 void
558 panic(const char *fmt, ...)
559 {
560 #ifdef SMP
561 	static volatile u_int panic_cpu = NOCPU;
562 	cpuset_t other_cpus;
563 #endif
564 	struct thread *td = curthread;
565 	int bootopt, newpanic;
566 	va_list ap;
567 	static char buf[256];
568 
569 	if (stop_scheduler_on_panic)
570 		spinlock_enter();
571 	else
572 		critical_enter();
573 
574 #ifdef SMP
575 	/*
576 	 * We don't want multiple CPU's to panic at the same time, so we
577 	 * use panic_cpu as a simple spinlock.  We have to keep checking
578 	 * panic_cpu if we are spinning in case the panic on the first
579 	 * CPU is canceled.
580 	 */
581 	if (panic_cpu != PCPU_GET(cpuid))
582 		while (atomic_cmpset_int(&panic_cpu, NOCPU,
583 		    PCPU_GET(cpuid)) == 0)
584 			while (panic_cpu != NOCPU)
585 				; /* nothing */
586 
587 	if (stop_scheduler_on_panic) {
588 		if (panicstr == NULL && !kdb_active) {
589 			other_cpus = all_cpus;
590 			CPU_CLR(PCPU_GET(cpuid), &other_cpus);
591 			stop_cpus_hard(other_cpus);
592 		}
593 
594 		/*
595 		 * We set stop_scheduler here and not in the block above,
596 		 * because we want to ensure that if panic has been called and
597 		 * stop_scheduler_on_panic is true, then stop_scheduler will
598 		 * always be set.  Even if panic has been entered from kdb.
599 		 */
600 		stop_scheduler = 1;
601 	}
602 #endif
603 
604 	bootopt = RB_AUTOBOOT;
605 	newpanic = 0;
606 	if (panicstr)
607 		bootopt |= RB_NOSYNC;
608 	else {
609 		bootopt |= RB_DUMP;
610 		panicstr = fmt;
611 		newpanic = 1;
612 	}
613 
614 	va_start(ap, fmt);
615 	if (newpanic) {
616 		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
617 		panicstr = buf;
618 		cngrab();
619 		printf("panic: %s\n", buf);
620 	} else {
621 		printf("panic: ");
622 		vprintf(fmt, ap);
623 		printf("\n");
624 	}
625 	va_end(ap);
626 #ifdef SMP
627 	printf("cpuid = %d\n", PCPU_GET(cpuid));
628 #endif
629 
630 #ifdef KDB
631 	if (newpanic && trace_on_panic)
632 		kdb_backtrace();
633 	if (debugger_on_panic)
634 		kdb_enter(KDB_WHY_PANIC, "panic");
635 #endif
636 	/*thread_lock(td); */
637 	td->td_flags |= TDF_INPANIC;
638 	/* thread_unlock(td); */
639 	if (!sync_on_panic)
640 		bootopt |= RB_NOSYNC;
641 	if (!stop_scheduler_on_panic)
642 		critical_exit();
643 	kern_reboot(bootopt);
644 }
645 
646 /*
647  * Support for poweroff delay.
648  *
649  * Please note that setting this delay too short might power off your machine
650  * before the write cache on your hard disk has been flushed, leading to
651  * soft-updates inconsistencies.
652  */
653 #ifndef POWEROFF_DELAY
654 # define POWEROFF_DELAY 5000
655 #endif
656 static int poweroff_delay = POWEROFF_DELAY;
657 
658 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
659     &poweroff_delay, 0, "Delay before poweroff to write disk caches (msec)");
660 
661 static void
662 poweroff_wait(void *junk, int howto)
663 {
664 
665 	if (!(howto & RB_POWEROFF) || poweroff_delay <= 0)
666 		return;
667 	DELAY(poweroff_delay * 1000);
668 }
669 
670 /*
671  * Some system processes (e.g. syncer) need to be stopped at appropriate
672  * points in their main loops prior to a system shutdown, so that they
673  * won't interfere with the shutdown process (e.g. by holding a disk buf
674  * to cause sync to fail).  For each of these system processes, register
675  * shutdown_kproc() as a handler for one of shutdown events.
676  */
677 static int kproc_shutdown_wait = 60;
678 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
679     &kproc_shutdown_wait, 0, "Max wait time (sec) to stop for each process");
680 
681 void
682 kproc_shutdown(void *arg, int howto)
683 {
684 	struct proc *p;
685 	int error;
686 
687 	if (panicstr)
688 		return;
689 
690 	p = (struct proc *)arg;
691 	printf("Waiting (max %d seconds) for system process `%s' to stop...",
692 	    kproc_shutdown_wait, p->p_comm);
693 	error = kproc_suspend(p, kproc_shutdown_wait * hz);
694 
695 	if (error == EWOULDBLOCK)
696 		printf("timed out\n");
697 	else
698 		printf("done\n");
699 }
700 
701 void
702 kthread_shutdown(void *arg, int howto)
703 {
704 	struct thread *td;
705 	int error;
706 
707 	if (panicstr)
708 		return;
709 
710 	td = (struct thread *)arg;
711 	printf("Waiting (max %d seconds) for system thread `%s' to stop...",
712 	    kproc_shutdown_wait, td->td_name);
713 	error = kthread_suspend(td, kproc_shutdown_wait * hz);
714 
715 	if (error == EWOULDBLOCK)
716 		printf("timed out\n");
717 	else
718 		printf("done\n");
719 }
720 
721 /* Registration of dumpers */
722 int
723 set_dumper(struct dumperinfo *di)
724 {
725 
726 	if (di == NULL) {
727 		bzero(&dumper, sizeof dumper);
728 		return (0);
729 	}
730 	if (dumper.dumper != NULL)
731 		return (EBUSY);
732 	dumper = *di;
733 	return (0);
734 }
735 
736 /* Call dumper with bounds checking. */
737 int
738 dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
739     off_t offset, size_t length)
740 {
741 
742 	if (length != 0 && (offset < di->mediaoffset ||
743 	    offset - di->mediaoffset + length > di->mediasize)) {
744 		printf("Attempt to write outside dump device boundaries.\n"
745 	    "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
746 		    (intmax_t)offset, (intmax_t)di->mediaoffset,
747 		    (uintmax_t)length, (intmax_t)di->mediasize);
748 		return (ENOSPC);
749 	}
750 	return (di->dumper(di->priv, virtual, physical, offset, length));
751 }
752 
753 void
754 mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver,
755     uint64_t dumplen, uint32_t blksz)
756 {
757 
758 	bzero(kdh, sizeof(*kdh));
759 	strncpy(kdh->magic, magic, sizeof(kdh->magic));
760 	strncpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
761 	kdh->version = htod32(KERNELDUMPVERSION);
762 	kdh->architectureversion = htod32(archver);
763 	kdh->dumplength = htod64(dumplen);
764 	kdh->dumptime = htod64(time_second);
765 	kdh->blocksize = htod32(blksz);
766 	strncpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
767 	strncpy(kdh->versionstring, version, sizeof(kdh->versionstring));
768 	if (panicstr != NULL)
769 		strncpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
770 	kdh->parity = kerneldump_parity(kdh);
771 }
772