xref: /freebsd/sys/kern/kern_shutdown.c (revision a10cee30c94cf5944826d2a495e9cdf339dfbcc8)
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 #include <sys/watchdog.h>
70 
71 #include <ddb/ddb.h>
72 
73 #include <machine/cpu.h>
74 #include <machine/pcb.h>
75 #include <machine/smp.h>
76 
77 #include <security/mac/mac_framework.h>
78 
79 #include <vm/vm.h>
80 #include <vm/vm_object.h>
81 #include <vm/vm_page.h>
82 #include <vm/vm_pager.h>
83 #include <vm/swap_pager.h>
84 
85 #include <sys/signalvar.h>
86 
87 #ifndef PANIC_REBOOT_WAIT_TIME
88 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
89 #endif
90 
91 /*
92  * Note that stdarg.h and the ANSI style va_start macro is used for both
93  * ANSI and traditional C compilers.
94  */
95 #include <machine/stdarg.h>
96 
97 #ifdef KDB
98 #ifdef KDB_UNATTENDED
99 int debugger_on_panic = 0;
100 #else
101 int debugger_on_panic = 1;
102 #endif
103 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
104     CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_TUN,
105     &debugger_on_panic, 0, "Run debugger on kernel panic");
106 TUNABLE_INT("debug.debugger_on_panic", &debugger_on_panic);
107 
108 #ifdef KDB_TRACE
109 static int trace_on_panic = 1;
110 #else
111 static int trace_on_panic = 0;
112 #endif
113 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
114     CTLFLAG_RW | CTLFLAG_SECURE | CTLFLAG_TUN,
115     &trace_on_panic, 0, "Print stack trace on kernel panic");
116 TUNABLE_INT("debug.trace_on_panic", &trace_on_panic);
117 #endif /* KDB */
118 
119 static int sync_on_panic = 0;
120 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
121 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
122 TUNABLE_INT("kern.sync_on_panic", &sync_on_panic);
123 
124 static int stop_scheduler_on_panic = 1;
125 SYSCTL_INT(_kern, OID_AUTO, stop_scheduler_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
126     &stop_scheduler_on_panic, 0, "stop scheduler upon entering panic");
127 TUNABLE_INT("kern.stop_scheduler_on_panic", &stop_scheduler_on_panic);
128 
129 static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
130     "Shutdown environment");
131 
132 #ifndef DIAGNOSTIC
133 static int show_busybufs;
134 #else
135 static int show_busybufs = 1;
136 #endif
137 SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
138 	&show_busybufs, 0, "");
139 
140 /*
141  * Variable panicstr contains argument to first call to panic; used as flag
142  * to indicate that the kernel has already called panic.
143  */
144 const char *panicstr;
145 
146 int dumping;				/* system is dumping */
147 int rebooting;				/* system is rebooting */
148 static struct dumperinfo dumper;	/* our selected dumper */
149 
150 /* Context information for dump-debuggers. */
151 static struct pcb dumppcb;		/* Registers. */
152 lwpid_t dumptid;			/* Thread ID. */
153 
154 static void poweroff_wait(void *, int);
155 static void shutdown_halt(void *junk, int howto);
156 static void shutdown_panic(void *junk, int howto);
157 static void shutdown_reset(void *junk, int howto);
158 
159 /* register various local shutdown events */
160 static void
161 shutdown_conf(void *unused)
162 {
163 
164 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
165 	    SHUTDOWN_PRI_FIRST);
166 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
167 	    SHUTDOWN_PRI_LAST + 100);
168 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
169 	    SHUTDOWN_PRI_LAST + 100);
170 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
171 	    SHUTDOWN_PRI_LAST + 200);
172 }
173 
174 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
175 
176 /*
177  * The system call that results in a reboot.
178  */
179 /* ARGSUSED */
180 int
181 sys_reboot(struct thread *td, struct reboot_args *uap)
182 {
183 	int error;
184 
185 	error = 0;
186 #ifdef MAC
187 	error = mac_system_check_reboot(td->td_ucred, uap->opt);
188 #endif
189 	if (error == 0)
190 		error = priv_check(td, PRIV_REBOOT);
191 	if (error == 0) {
192 		mtx_lock(&Giant);
193 		kern_reboot(uap->opt);
194 		mtx_unlock(&Giant);
195 	}
196 	return (error);
197 }
198 
199 /*
200  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
201  */
202 static int shutdown_howto = 0;
203 
204 void
205 shutdown_nice(int howto)
206 {
207 
208 	shutdown_howto = howto;
209 
210 	/* Send a signal to init(8) and have it shutdown the world */
211 	if (initproc != NULL) {
212 		PROC_LOCK(initproc);
213 		kern_psignal(initproc, SIGINT);
214 		PROC_UNLOCK(initproc);
215 	} else {
216 		/* No init(8) running, so simply reboot */
217 		kern_reboot(RB_NOSYNC);
218 	}
219 	return;
220 }
221 static int	waittime = -1;
222 
223 static void
224 print_uptime(void)
225 {
226 	int f;
227 	struct timespec ts;
228 
229 	getnanouptime(&ts);
230 	printf("Uptime: ");
231 	f = 0;
232 	if (ts.tv_sec >= 86400) {
233 		printf("%ldd", (long)ts.tv_sec / 86400);
234 		ts.tv_sec %= 86400;
235 		f = 1;
236 	}
237 	if (f || ts.tv_sec >= 3600) {
238 		printf("%ldh", (long)ts.tv_sec / 3600);
239 		ts.tv_sec %= 3600;
240 		f = 1;
241 	}
242 	if (f || ts.tv_sec >= 60) {
243 		printf("%ldm", (long)ts.tv_sec / 60);
244 		ts.tv_sec %= 60;
245 		f = 1;
246 	}
247 	printf("%lds\n", (long)ts.tv_sec);
248 }
249 
250 int
251 doadump(boolean_t textdump)
252 {
253 	boolean_t coredump;
254 
255 	if (dumping)
256 		return (EBUSY);
257 	if (dumper.dumper == NULL)
258 		return (ENXIO);
259 
260 	savectx(&dumppcb);
261 	dumptid = curthread->td_tid;
262 	dumping++;
263 
264 	coredump = TRUE;
265 #ifdef DDB
266 	if (textdump && textdump_pending) {
267 		coredump = FALSE;
268 		textdump_dumpsys(&dumper);
269 	}
270 #endif
271 	if (coredump)
272 		dumpsys(&dumper);
273 
274 	dumping--;
275 	return (0);
276 }
277 
278 static int
279 isbufbusy(struct buf *bp)
280 {
281 	if (((bp->b_flags & (B_INVAL | B_PERSISTENT)) == 0 &&
282 	    BUF_ISLOCKED(bp)) ||
283 	    ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI))
284 		return (1);
285 	return (0);
286 }
287 
288 /*
289  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
290  */
291 void
292 kern_reboot(int howto)
293 {
294 	static int first_buf_printf = 1;
295 
296 #if defined(SMP)
297 	/*
298 	 * Bind us to CPU 0 so that all shutdown code runs there.  Some
299 	 * systems don't shutdown properly (i.e., ACPI power off) if we
300 	 * run on another processor.
301 	 */
302 	if (!SCHEDULER_STOPPED()) {
303 		thread_lock(curthread);
304 		sched_bind(curthread, 0);
305 		thread_unlock(curthread);
306 		KASSERT(PCPU_GET(cpuid) == 0, ("boot: not running on cpu 0"));
307 	}
308 #endif
309 	/* We're in the process of rebooting. */
310 	rebooting = 1;
311 
312 	/* collect extra flags that shutdown_nice might have set */
313 	howto |= shutdown_howto;
314 
315 	/* We are out of the debugger now. */
316 	kdb_active = 0;
317 
318 	/*
319 	 * Do any callouts that should be done BEFORE syncing the filesystems.
320 	 */
321 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
322 
323 	/*
324 	 * Now sync filesystems
325 	 */
326 	if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
327 		register struct buf *bp;
328 		int iter, nbusy, pbusy;
329 #ifndef PREEMPTION
330 		int subiter;
331 #endif
332 
333 		waittime = 0;
334 
335 		wdog_kern_pat(WD_LASTVAL);
336 		sys_sync(curthread, NULL);
337 
338 		/*
339 		 * With soft updates, some buffers that are
340 		 * written will be remarked as dirty until other
341 		 * buffers are written.
342 		 */
343 		for (iter = pbusy = 0; iter < 20; iter++) {
344 			nbusy = 0;
345 			for (bp = &buf[nbuf]; --bp >= buf; )
346 				if (isbufbusy(bp))
347 					nbusy++;
348 			if (nbusy == 0) {
349 				if (first_buf_printf)
350 					printf("All buffers synced.");
351 				break;
352 			}
353 			if (first_buf_printf) {
354 				printf("Syncing disks, buffers remaining... ");
355 				first_buf_printf = 0;
356 			}
357 			printf("%d ", nbusy);
358 			if (nbusy < pbusy)
359 				iter = 0;
360 			pbusy = nbusy;
361 
362 			wdog_kern_pat(WD_LASTVAL);
363 			sys_sync(curthread, NULL);
364 
365 #ifdef PREEMPTION
366 			/*
367 			 * Drop Giant and spin for a while to allow
368 			 * interrupt threads to run.
369 			 */
370 			DROP_GIANT();
371 			DELAY(50000 * iter);
372 			PICKUP_GIANT();
373 #else
374 			/*
375 			 * Drop Giant and context switch several times to
376 			 * allow interrupt threads to run.
377 			 */
378 			DROP_GIANT();
379 			for (subiter = 0; subiter < 50 * iter; subiter++) {
380 				thread_lock(curthread);
381 				mi_switch(SW_VOL, NULL);
382 				thread_unlock(curthread);
383 				DELAY(1000);
384 			}
385 			PICKUP_GIANT();
386 #endif
387 		}
388 		printf("\n");
389 		/*
390 		 * Count only busy local buffers to prevent forcing
391 		 * a fsck if we're just a client of a wedged NFS server
392 		 */
393 		nbusy = 0;
394 		for (bp = &buf[nbuf]; --bp >= buf; ) {
395 			if (isbufbusy(bp)) {
396 #if 0
397 /* XXX: This is bogus.  We should probably have a BO_REMOTE flag instead */
398 				if (bp->b_dev == NULL) {
399 					TAILQ_REMOVE(&mountlist,
400 					    bp->b_vp->v_mount, mnt_list);
401 					continue;
402 				}
403 #endif
404 				nbusy++;
405 				if (show_busybufs > 0) {
406 					printf(
407 	    "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:",
408 					    nbusy, bp, bp->b_vp, bp->b_flags,
409 					    (intmax_t)bp->b_blkno,
410 					    (intmax_t)bp->b_lblkno);
411 					BUF_LOCKPRINTINFO(bp);
412 					if (show_busybufs > 1)
413 						vn_printf(bp->b_vp,
414 						    "vnode content: ");
415 				}
416 			}
417 		}
418 		if (nbusy) {
419 			/*
420 			 * Failed to sync all blocks. Indicate this and don't
421 			 * unmount filesystems (thus forcing an fsck on reboot).
422 			 */
423 			printf("Giving up on %d buffers\n", nbusy);
424 			DELAY(5000000);	/* 5 seconds */
425 		} else {
426 			if (!first_buf_printf)
427 				printf("Final sync complete\n");
428 			/*
429 			 * Unmount filesystems
430 			 */
431 			if (panicstr == 0)
432 				vfs_unmountall();
433 		}
434 		swapoff_all();
435 		DELAY(100000);		/* wait for console output to finish */
436 	}
437 
438 	print_uptime();
439 
440 	cngrab();
441 
442 	/*
443 	 * Ok, now do things that assume all filesystem activity has
444 	 * been completed.
445 	 */
446 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
447 
448 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
449 		doadump(TRUE);
450 
451 	/* Now that we're going to really halt the system... */
452 	EVENTHANDLER_INVOKE(shutdown_final, howto);
453 
454 	for(;;) ;	/* safety against shutdown_reset not working */
455 	/* NOTREACHED */
456 }
457 
458 /*
459  * If the shutdown was a clean halt, behave accordingly.
460  */
461 static void
462 shutdown_halt(void *junk, int howto)
463 {
464 
465 	if (howto & RB_HALT) {
466 		printf("\n");
467 		printf("The operating system has halted.\n");
468 		printf("Please press any key to reboot.\n\n");
469 		switch (cngetc()) {
470 		case -1:		/* No console, just die */
471 			cpu_halt();
472 			/* NOTREACHED */
473 		default:
474 			howto &= ~RB_HALT;
475 			break;
476 		}
477 	}
478 }
479 
480 /*
481  * Check to see if the system paniced, pause and then reboot
482  * according to the specified delay.
483  */
484 static void
485 shutdown_panic(void *junk, int howto)
486 {
487 	int loop;
488 
489 	if (howto & RB_DUMP) {
490 		if (PANIC_REBOOT_WAIT_TIME != 0) {
491 			if (PANIC_REBOOT_WAIT_TIME != -1) {
492 				printf("Automatic reboot in %d seconds - "
493 				       "press a key on the console to abort\n",
494 					PANIC_REBOOT_WAIT_TIME);
495 				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
496 				     loop > 0; --loop) {
497 					DELAY(1000 * 100); /* 1/10th second */
498 					/* Did user type a key? */
499 					if (cncheckc() != -1)
500 						break;
501 				}
502 				if (!loop)
503 					return;
504 			}
505 		} else { /* zero time specified - reboot NOW */
506 			return;
507 		}
508 		printf("--> Press a key on the console to reboot,\n");
509 		printf("--> or switch off the system now.\n");
510 		cngetc();
511 	}
512 }
513 
514 /*
515  * Everything done, now reset
516  */
517 static void
518 shutdown_reset(void *junk, int howto)
519 {
520 
521 	printf("Rebooting...\n");
522 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
523 
524 	/*
525 	 * Acquiring smp_ipi_mtx here has a double effect:
526 	 * - it disables interrupts avoiding CPU0 preemption
527 	 *   by fast handlers (thus deadlocking  against other CPUs)
528 	 * - it avoids deadlocks against smp_rendezvous() or, more
529 	 *   generally, threads busy-waiting, with this spinlock held,
530 	 *   and waiting for responses by threads on other CPUs
531 	 *   (ie. smp_tlb_shootdown()).
532 	 *
533 	 * For the !SMP case it just needs to handle the former problem.
534 	 */
535 #ifdef SMP
536 	mtx_lock_spin(&smp_ipi_mtx);
537 #else
538 	spinlock_enter();
539 #endif
540 
541 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
542 	cpu_reset();
543 	/* NOTREACHED */ /* assuming reset worked */
544 }
545 
546 /*
547  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
548  * and then reboots.  If we are called twice, then we avoid trying to sync
549  * the disks as this often leads to recursive panics.
550  */
551 void
552 panic(const char *fmt, ...)
553 {
554 #ifdef SMP
555 	static volatile u_int panic_cpu = NOCPU;
556 	cpuset_t other_cpus;
557 #endif
558 	struct thread *td = curthread;
559 	int bootopt, newpanic;
560 	va_list ap;
561 	static char buf[256];
562 
563 	if (stop_scheduler_on_panic)
564 		spinlock_enter();
565 	else
566 		critical_enter();
567 
568 #ifdef SMP
569 	/*
570 	 * We don't want multiple CPU's to panic at the same time, so we
571 	 * use panic_cpu as a simple spinlock.  We have to keep checking
572 	 * panic_cpu if we are spinning in case the panic on the first
573 	 * CPU is canceled.
574 	 */
575 	if (panic_cpu != PCPU_GET(cpuid))
576 		while (atomic_cmpset_int(&panic_cpu, NOCPU,
577 		    PCPU_GET(cpuid)) == 0)
578 			while (panic_cpu != NOCPU)
579 				; /* nothing */
580 
581 	if (stop_scheduler_on_panic) {
582 		if (panicstr == NULL && !kdb_active) {
583 			other_cpus = all_cpus;
584 			CPU_CLR(PCPU_GET(cpuid), &other_cpus);
585 			stop_cpus_hard(other_cpus);
586 		}
587 
588 		/*
589 		 * We set stop_scheduler here and not in the block above,
590 		 * because we want to ensure that if panic has been called and
591 		 * stop_scheduler_on_panic is true, then stop_scheduler will
592 		 * always be set.  Even if panic has been entered from kdb.
593 		 */
594 		td->td_stopsched = 1;
595 	}
596 #endif
597 
598 	bootopt = RB_AUTOBOOT;
599 	newpanic = 0;
600 	if (panicstr)
601 		bootopt |= RB_NOSYNC;
602 	else {
603 		bootopt |= RB_DUMP;
604 		panicstr = fmt;
605 		newpanic = 1;
606 	}
607 
608 	va_start(ap, fmt);
609 	if (newpanic) {
610 		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
611 		panicstr = buf;
612 		cngrab();
613 		printf("panic: %s\n", buf);
614 	} else {
615 		printf("panic: ");
616 		vprintf(fmt, ap);
617 		printf("\n");
618 	}
619 	va_end(ap);
620 #ifdef SMP
621 	printf("cpuid = %d\n", PCPU_GET(cpuid));
622 #endif
623 
624 #ifdef KDB
625 	if (newpanic && trace_on_panic)
626 		kdb_backtrace();
627 	if (debugger_on_panic)
628 		kdb_enter(KDB_WHY_PANIC, "panic");
629 #endif
630 	/*thread_lock(td); */
631 	td->td_flags |= TDF_INPANIC;
632 	/* thread_unlock(td); */
633 	if (!sync_on_panic)
634 		bootopt |= RB_NOSYNC;
635 	if (!stop_scheduler_on_panic)
636 		critical_exit();
637 	kern_reboot(bootopt);
638 }
639 
640 /*
641  * Support for poweroff delay.
642  *
643  * Please note that setting this delay too short might power off your machine
644  * before the write cache on your hard disk has been flushed, leading to
645  * soft-updates inconsistencies.
646  */
647 #ifndef POWEROFF_DELAY
648 # define POWEROFF_DELAY 5000
649 #endif
650 static int poweroff_delay = POWEROFF_DELAY;
651 
652 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
653     &poweroff_delay, 0, "Delay before poweroff to write disk caches (msec)");
654 
655 static void
656 poweroff_wait(void *junk, int howto)
657 {
658 
659 	if (!(howto & RB_POWEROFF) || poweroff_delay <= 0)
660 		return;
661 	DELAY(poweroff_delay * 1000);
662 }
663 
664 /*
665  * Some system processes (e.g. syncer) need to be stopped at appropriate
666  * points in their main loops prior to a system shutdown, so that they
667  * won't interfere with the shutdown process (e.g. by holding a disk buf
668  * to cause sync to fail).  For each of these system processes, register
669  * shutdown_kproc() as a handler for one of shutdown events.
670  */
671 static int kproc_shutdown_wait = 60;
672 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
673     &kproc_shutdown_wait, 0, "Max wait time (sec) to stop for each process");
674 
675 void
676 kproc_shutdown(void *arg, int howto)
677 {
678 	struct proc *p;
679 	int error;
680 
681 	if (panicstr)
682 		return;
683 
684 	p = (struct proc *)arg;
685 	printf("Waiting (max %d seconds) for system process `%s' to stop...",
686 	    kproc_shutdown_wait, p->p_comm);
687 	error = kproc_suspend(p, kproc_shutdown_wait * hz);
688 
689 	if (error == EWOULDBLOCK)
690 		printf("timed out\n");
691 	else
692 		printf("done\n");
693 }
694 
695 void
696 kthread_shutdown(void *arg, int howto)
697 {
698 	struct thread *td;
699 	int error;
700 
701 	if (panicstr)
702 		return;
703 
704 	td = (struct thread *)arg;
705 	printf("Waiting (max %d seconds) for system thread `%s' to stop...",
706 	    kproc_shutdown_wait, td->td_name);
707 	error = kthread_suspend(td, kproc_shutdown_wait * hz);
708 
709 	if (error == EWOULDBLOCK)
710 		printf("timed out\n");
711 	else
712 		printf("done\n");
713 }
714 
715 /* Registration of dumpers */
716 int
717 set_dumper(struct dumperinfo *di)
718 {
719 
720 	if (di == NULL) {
721 		bzero(&dumper, sizeof dumper);
722 		return (0);
723 	}
724 	if (dumper.dumper != NULL)
725 		return (EBUSY);
726 	dumper = *di;
727 	return (0);
728 }
729 
730 /* Call dumper with bounds checking. */
731 int
732 dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
733     off_t offset, size_t length)
734 {
735 
736 	if (length != 0 && (offset < di->mediaoffset ||
737 	    offset - di->mediaoffset + length > di->mediasize)) {
738 		printf("Attempt to write outside dump device boundaries.\n"
739 	    "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
740 		    (intmax_t)offset, (intmax_t)di->mediaoffset,
741 		    (uintmax_t)length, (intmax_t)di->mediasize);
742 		return (ENOSPC);
743 	}
744 	return (di->dumper(di->priv, virtual, physical, offset, length));
745 }
746 
747 void
748 mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver,
749     uint64_t dumplen, uint32_t blksz)
750 {
751 
752 	bzero(kdh, sizeof(*kdh));
753 	strncpy(kdh->magic, magic, sizeof(kdh->magic));
754 	strncpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
755 	kdh->version = htod32(KERNELDUMPVERSION);
756 	kdh->architectureversion = htod32(archver);
757 	kdh->dumplength = htod64(dumplen);
758 	kdh->dumptime = htod64(time_second);
759 	kdh->blocksize = htod32(blksz);
760 	strncpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
761 	strncpy(kdh->versionstring, version, sizeof(kdh->versionstring));
762 	if (panicstr != NULL)
763 		strncpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
764 	kdh->parity = kerneldump_parity(kdh);
765 }
766