xref: /freebsd/sys/kern/kern_shutdown.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
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_show_busybufs.h"
44 #include "opt_sched.h"
45 #include "opt_watchdog.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/bio.h>
50 #include <sys/buf.h>
51 #include <sys/conf.h>
52 #include <sys/cons.h>
53 #include <sys/eventhandler.h>
54 #include <sys/jail.h>
55 #include <sys/kdb.h>
56 #include <sys/kernel.h>
57 #include <sys/kerneldump.h>
58 #include <sys/kthread.h>
59 #include <sys/malloc.h>
60 #include <sys/mount.h>
61 #include <sys/priv.h>
62 #include <sys/proc.h>
63 #include <sys/reboot.h>
64 #include <sys/resourcevar.h>
65 #include <sys/sched.h>
66 #include <sys/smp.h>
67 #include <sys/sysctl.h>
68 #include <sys/sysproto.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, CTLFLAG_RW | CTLFLAG_TUN,
106 	&debugger_on_panic, 0, "Run debugger on kernel panic");
107 TUNABLE_INT("debug.debugger_on_panic", &debugger_on_panic);
108 
109 #ifdef KDB_TRACE
110 static int trace_on_panic = 1;
111 #else
112 static int trace_on_panic = 0;
113 #endif
114 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW | 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 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
125 
126 /*
127  * Variable panicstr contains argument to first call to panic; used as flag
128  * to indicate that the kernel has already called panic.
129  */
130 const char *panicstr;
131 
132 int dumping;				/* system is dumping */
133 int rebooting;				/* system is rebooting */
134 static struct dumperinfo dumper;	/* our selected dumper */
135 
136 /* Context information for dump-debuggers. */
137 static struct pcb dumppcb;		/* Registers. */
138 static lwpid_t dumptid;			/* Thread ID. */
139 
140 static void poweroff_wait(void *, int);
141 static void shutdown_halt(void *junk, int howto);
142 static void shutdown_panic(void *junk, int howto);
143 static void shutdown_reset(void *junk, int howto);
144 
145 /* register various local shutdown events */
146 static void
147 shutdown_conf(void *unused)
148 {
149 
150 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
151 	    SHUTDOWN_PRI_FIRST);
152 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
153 	    SHUTDOWN_PRI_LAST + 100);
154 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
155 	    SHUTDOWN_PRI_LAST + 100);
156 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
157 	    SHUTDOWN_PRI_LAST + 200);
158 }
159 
160 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
161 
162 /*
163  * The system call that results in a reboot.
164  */
165 /* ARGSUSED */
166 int
167 reboot(struct thread *td, struct reboot_args *uap)
168 {
169 	int error;
170 
171 	error = 0;
172 #ifdef MAC
173 	error = mac_system_check_reboot(td->td_ucred, uap->opt);
174 #endif
175 	if (error == 0)
176 		error = priv_check(td, PRIV_REBOOT);
177 	if (error == 0) {
178 		mtx_lock(&Giant);
179 		kern_reboot(uap->opt);
180 		mtx_unlock(&Giant);
181 	}
182 	return (error);
183 }
184 
185 /*
186  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
187  */
188 static int shutdown_howto = 0;
189 
190 void
191 shutdown_nice(int howto)
192 {
193 
194 	shutdown_howto = howto;
195 
196 	/* Send a signal to init(8) and have it shutdown the world */
197 	if (initproc != NULL) {
198 		PROC_LOCK(initproc);
199 		psignal(initproc, SIGINT);
200 		PROC_UNLOCK(initproc);
201 	} else {
202 		/* No init(8) running, so simply reboot */
203 		kern_reboot(RB_NOSYNC);
204 	}
205 	return;
206 }
207 static int	waittime = -1;
208 
209 static void
210 print_uptime(void)
211 {
212 	int f;
213 	struct timespec ts;
214 
215 	getnanouptime(&ts);
216 	printf("Uptime: ");
217 	f = 0;
218 	if (ts.tv_sec >= 86400) {
219 		printf("%ldd", (long)ts.tv_sec / 86400);
220 		ts.tv_sec %= 86400;
221 		f = 1;
222 	}
223 	if (f || ts.tv_sec >= 3600) {
224 		printf("%ldh", (long)ts.tv_sec / 3600);
225 		ts.tv_sec %= 3600;
226 		f = 1;
227 	}
228 	if (f || ts.tv_sec >= 60) {
229 		printf("%ldm", (long)ts.tv_sec / 60);
230 		ts.tv_sec %= 60;
231 		f = 1;
232 	}
233 	printf("%lds\n", (long)ts.tv_sec);
234 }
235 
236 static void
237 doadump(void)
238 {
239 
240 	/*
241 	 * Sometimes people have to call this from the kernel debugger.
242 	 * (if 'panic' can not dump)
243 	 * Give them a clue as to why they can't dump.
244 	 */
245 	if (dumper.dumper == NULL) {
246 		printf("Cannot dump. Device not defined or unavailable.\n");
247 		return;
248 	}
249 
250 	savectx(&dumppcb);
251 	dumptid = curthread->td_tid;
252 	dumping++;
253 #ifdef DDB
254 	if (textdump_pending)
255 		textdump_dumpsys(&dumper);
256 	else
257 #endif
258 		dumpsys(&dumper);
259 	dumping--;
260 }
261 
262 static int
263 isbufbusy(struct buf *bp)
264 {
265 	if (((bp->b_flags & (B_INVAL | B_PERSISTENT)) == 0 &&
266 	    BUF_ISLOCKED(bp)) ||
267 	    ((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI))
268 		return (1);
269 	return (0);
270 }
271 
272 /*
273  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
274  */
275 void
276 kern_reboot(int howto)
277 {
278 	static int first_buf_printf = 1;
279 
280 #if defined(SMP)
281 	/*
282 	 * Bind us to CPU 0 so that all shutdown code runs there.  Some
283 	 * systems don't shutdown properly (i.e., ACPI power off) if we
284 	 * run on another processor.
285 	 */
286 	thread_lock(curthread);
287 	sched_bind(curthread, 0);
288 	thread_unlock(curthread);
289 	KASSERT(PCPU_GET(cpuid) == 0, ("%s: not running on cpu 0", __func__));
290 #endif
291 	/* We're in the process of rebooting. */
292 	rebooting = 1;
293 
294 	/* collect extra flags that shutdown_nice might have set */
295 	howto |= shutdown_howto;
296 
297 	/* We are out of the debugger now. */
298 	kdb_active = 0;
299 
300 	/*
301 	 * Do any callouts that should be done BEFORE syncing the filesystems.
302 	 */
303 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
304 
305 	/*
306 	 * Now sync filesystems
307 	 */
308 	if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
309 		register struct buf *bp;
310 		int iter, nbusy, pbusy;
311 #ifndef PREEMPTION
312 		int subiter;
313 #endif
314 
315 		waittime = 0;
316 
317 #ifdef SW_WATCHDOG
318 		wdog_kern_pat(WD_LASTVAL);
319 #endif
320 		sync(curthread, NULL);
321 
322 		/*
323 		 * With soft updates, some buffers that are
324 		 * written will be remarked as dirty until other
325 		 * buffers are written.
326 		 */
327 		for (iter = pbusy = 0; iter < 20; iter++) {
328 			nbusy = 0;
329 			for (bp = &buf[nbuf]; --bp >= buf; )
330 				if (isbufbusy(bp))
331 					nbusy++;
332 			if (nbusy == 0) {
333 				if (first_buf_printf)
334 					printf("All buffers synced.");
335 				break;
336 			}
337 			if (first_buf_printf) {
338 				printf("Syncing disks, buffers remaining... ");
339 				first_buf_printf = 0;
340 			}
341 			printf("%d ", nbusy);
342 			if (nbusy < pbusy)
343 				iter = 0;
344 			pbusy = nbusy;
345 #ifdef SW_WATCHDOG
346 			wdog_kern_pat(WD_LASTVAL);
347 #endif
348 			sync(curthread, NULL);
349 
350 #ifdef PREEMPTION
351 			/*
352 			 * Drop Giant and spin for a while to allow
353 			 * interrupt threads to run.
354 			 */
355 			DROP_GIANT();
356 			DELAY(50000 * iter);
357 			PICKUP_GIANT();
358 #else
359 			/*
360 			 * Drop Giant and context switch several times to
361 			 * allow interrupt threads to run.
362 			 */
363 			DROP_GIANT();
364 			for (subiter = 0; subiter < 50 * iter; subiter++) {
365 				thread_lock(curthread);
366 				mi_switch(SW_VOL, NULL);
367 				thread_unlock(curthread);
368 				DELAY(1000);
369 			}
370 			PICKUP_GIANT();
371 #endif
372 		}
373 		printf("\n");
374 		/*
375 		 * Count only busy local buffers to prevent forcing
376 		 * a fsck if we're just a client of a wedged NFS server
377 		 */
378 		nbusy = 0;
379 		for (bp = &buf[nbuf]; --bp >= buf; ) {
380 			if (isbufbusy(bp)) {
381 #if 0
382 /* XXX: This is bogus.  We should probably have a BO_REMOTE flag instead */
383 				if (bp->b_dev == NULL) {
384 					TAILQ_REMOVE(&mountlist,
385 					    bp->b_vp->v_mount, mnt_list);
386 					continue;
387 				}
388 #endif
389 				nbusy++;
390 #if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
391 				printf(
392 			    "%d: bufobj:%p, flags:%0x, blkno:%ld, lblkno:%ld\n",
393 				    nbusy, bp->b_bufobj,
394 				    bp->b_flags, (long)bp->b_blkno,
395 				    (long)bp->b_lblkno);
396 #endif
397 			}
398 		}
399 		if (nbusy) {
400 			/*
401 			 * Failed to sync all blocks. Indicate this and don't
402 			 * unmount filesystems (thus forcing an fsck on reboot).
403 			 */
404 			printf("Giving up on %d buffers\n", nbusy);
405 			DELAY(5000000);	/* 5 seconds */
406 		} else {
407 			if (!first_buf_printf)
408 				printf("Final sync complete\n");
409 			/*
410 			 * Unmount filesystems
411 			 */
412 			if (panicstr == 0)
413 				vfs_unmountall();
414 		}
415 		swapoff_all();
416 		DELAY(100000);		/* wait for console output to finish */
417 	}
418 
419 	print_uptime();
420 
421 	/*
422 	 * Ok, now do things that assume all filesystem activity has
423 	 * been completed.
424 	 */
425 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
426 
427 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
428 		doadump();
429 
430 	/* Now that we're going to really halt the system... */
431 	EVENTHANDLER_INVOKE(shutdown_final, howto);
432 
433 	for(;;) ;	/* safety against shutdown_reset not working */
434 	/* NOTREACHED */
435 }
436 
437 /*
438  * If the shutdown was a clean halt, behave accordingly.
439  */
440 static void
441 shutdown_halt(void *junk, int howto)
442 {
443 
444 	if (howto & RB_HALT) {
445 		printf("\n");
446 		printf("The operating system has halted.\n");
447 		printf("Please press any key to reboot.\n\n");
448 		switch (cngetc()) {
449 		case -1:		/* No console, just die */
450 			cpu_halt();
451 			/* NOTREACHED */
452 		default:
453 			howto &= ~RB_HALT;
454 			break;
455 		}
456 	}
457 }
458 
459 /*
460  * Check to see if the system paniced, pause and then reboot
461  * according to the specified delay.
462  */
463 static void
464 shutdown_panic(void *junk, int howto)
465 {
466 	int loop;
467 
468 	if (howto & RB_DUMP) {
469 		if (PANIC_REBOOT_WAIT_TIME != 0) {
470 			if (PANIC_REBOOT_WAIT_TIME != -1) {
471 				printf("Automatic reboot in %d seconds - "
472 				       "press a key on the console to abort\n",
473 					PANIC_REBOOT_WAIT_TIME);
474 				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
475 				     loop > 0; --loop) {
476 					DELAY(1000 * 100); /* 1/10th second */
477 					/* Did user type a key? */
478 					if (cncheckc() != -1)
479 						break;
480 				}
481 				if (!loop)
482 					return;
483 			}
484 		} else { /* zero time specified - reboot NOW */
485 			return;
486 		}
487 		printf("--> Press a key on the console to reboot,\n");
488 		printf("--> or switch off the system now.\n");
489 		cngetc();
490 	}
491 }
492 
493 /*
494  * Everything done, now reset
495  */
496 static void
497 shutdown_reset(void *junk, int howto)
498 {
499 
500 	printf("Rebooting...\n");
501 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
502 
503 	/*
504 	 * Acquiring smp_ipi_mtx here has a double effect:
505 	 * - it disables interrupts avoiding CPU0 preemption
506 	 *   by fast handlers (thus deadlocking  against other CPUs)
507 	 * - it avoids deadlocks against smp_rendezvous() or, more
508 	 *   generally, threads busy-waiting, with this spinlock held,
509 	 *   and waiting for responses by threads on other CPUs
510 	 *   (ie. smp_tlb_shootdown()).
511 	 *
512 	 * For the !SMP case it just needs to handle the former problem.
513 	 */
514 #ifdef SMP
515 	mtx_lock_spin(&smp_ipi_mtx);
516 #else
517 	spinlock_enter();
518 #endif
519 
520 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
521 	cpu_reset();
522 	/* NOTREACHED */ /* assuming reset worked */
523 }
524 
525 /*
526  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
527  * and then reboots.  If we are called twice, then we avoid trying to sync
528  * the disks as this often leads to recursive panics.
529  */
530 void
531 panic(const char *fmt, ...)
532 {
533 #ifdef SMP
534 	static volatile u_int panic_cpu = NOCPU;
535 #endif
536 	struct thread *td = curthread;
537 	int bootopt, newpanic;
538 	va_list ap;
539 	static char buf[256];
540 
541 	critical_enter();
542 #ifdef SMP
543 	/*
544 	 * We don't want multiple CPU's to panic at the same time, so we
545 	 * use panic_cpu as a simple spinlock.  We have to keep checking
546 	 * panic_cpu if we are spinning in case the panic on the first
547 	 * CPU is canceled.
548 	 */
549 	if (panic_cpu != PCPU_GET(cpuid))
550 		while (atomic_cmpset_int(&panic_cpu, NOCPU,
551 		    PCPU_GET(cpuid)) == 0)
552 			while (panic_cpu != NOCPU)
553 				; /* nothing */
554 #endif
555 
556 	bootopt = RB_AUTOBOOT | RB_DUMP;
557 	newpanic = 0;
558 	if (panicstr)
559 		bootopt |= RB_NOSYNC;
560 	else {
561 		panicstr = fmt;
562 		newpanic = 1;
563 	}
564 
565 	va_start(ap, fmt);
566 	if (newpanic) {
567 		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
568 		panicstr = buf;
569 		printf("panic: %s\n", buf);
570 	} else {
571 		printf("panic: ");
572 		vprintf(fmt, ap);
573 		printf("\n");
574 	}
575 	va_end(ap);
576 #ifdef SMP
577 	printf("cpuid = %d\n", PCPU_GET(cpuid));
578 #endif
579 
580 #ifdef KDB
581 	if (newpanic && trace_on_panic)
582 		kdb_backtrace();
583 	if (debugger_on_panic)
584 		kdb_enter(KDB_WHY_PANIC, "panic");
585 #ifdef RESTARTABLE_PANICS
586 	/* See if the user aborted the panic, in which case we continue. */
587 	if (panicstr == NULL) {
588 #ifdef SMP
589 		atomic_store_rel_int(&panic_cpu, NOCPU);
590 #endif
591 		return;
592 	}
593 #endif
594 #endif
595 	/*thread_lock(td); */
596 	td->td_flags |= TDF_INPANIC;
597 	/* thread_unlock(td); */
598 	if (!sync_on_panic)
599 		bootopt |= RB_NOSYNC;
600 	critical_exit();
601 	kern_reboot(bootopt);
602 }
603 
604 /*
605  * Support for poweroff delay.
606  *
607  * Please note that setting this delay too short might power off your machine
608  * before the write cache on your hard disk has been flushed, leading to
609  * soft-updates inconsistencies.
610  */
611 #ifndef POWEROFF_DELAY
612 # define POWEROFF_DELAY 5000
613 #endif
614 static int poweroff_delay = POWEROFF_DELAY;
615 
616 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
617 	&poweroff_delay, 0, "");
618 
619 static void
620 poweroff_wait(void *junk, int howto)
621 {
622 
623 	if (!(howto & RB_POWEROFF) || poweroff_delay <= 0)
624 		return;
625 	DELAY(poweroff_delay * 1000);
626 }
627 
628 /*
629  * Some system processes (e.g. syncer) need to be stopped at appropriate
630  * points in their main loops prior to a system shutdown, so that they
631  * won't interfere with the shutdown process (e.g. by holding a disk buf
632  * to cause sync to fail).  For each of these system processes, register
633  * shutdown_kproc() as a handler for one of shutdown events.
634  */
635 static int kproc_shutdown_wait = 60;
636 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
637     &kproc_shutdown_wait, 0, "");
638 
639 void
640 kproc_shutdown(void *arg, int howto)
641 {
642 	struct proc *p;
643 	int error;
644 
645 	if (panicstr)
646 		return;
647 
648 	p = (struct proc *)arg;
649 	printf("Waiting (max %d seconds) for system process `%s' to stop...",
650 	    kproc_shutdown_wait, p->p_comm);
651 	error = kproc_suspend(p, kproc_shutdown_wait * hz);
652 
653 	if (error == EWOULDBLOCK)
654 		printf("timed out\n");
655 	else
656 		printf("done\n");
657 }
658 
659 void
660 kthread_shutdown(void *arg, int howto)
661 {
662 	struct thread *td;
663 	int error;
664 
665 	if (panicstr)
666 		return;
667 
668 	td = (struct thread *)arg;
669 	printf("Waiting (max %d seconds) for system thread `%s' to stop...",
670 	    kproc_shutdown_wait, td->td_name);
671 	error = kthread_suspend(td, kproc_shutdown_wait * hz);
672 
673 	if (error == EWOULDBLOCK)
674 		printf("timed out\n");
675 	else
676 		printf("done\n");
677 }
678 
679 /* Registration of dumpers */
680 int
681 set_dumper(struct dumperinfo *di)
682 {
683 
684 	if (di == NULL) {
685 		bzero(&dumper, sizeof dumper);
686 		return (0);
687 	}
688 	if (dumper.dumper != NULL)
689 		return (EBUSY);
690 	dumper = *di;
691 	return (0);
692 }
693 
694 /* Call dumper with bounds checking. */
695 int
696 dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
697     off_t offset, size_t length)
698 {
699 
700 	if (length != 0 && (offset < di->mediaoffset ||
701 	    offset - di->mediaoffset + length > di->mediasize)) {
702 		printf("Attempt to write outside dump device boundaries.\n");
703 		return (ENXIO);
704 	}
705 	return (di->dumper(di->priv, virtual, physical, offset, length));
706 }
707 
708 void
709 mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver,
710     uint64_t dumplen, uint32_t blksz)
711 {
712 
713 	bzero(kdh, sizeof(*kdh));
714 	strncpy(kdh->magic, magic, sizeof(kdh->magic));
715 	strncpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
716 	kdh->version = htod32(KERNELDUMPVERSION);
717 	kdh->architectureversion = htod32(archver);
718 	kdh->dumplength = htod64(dumplen);
719 	kdh->dumptime = htod64(time_second);
720 	kdh->blocksize = htod32(blksz);
721 	strncpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
722 	strncpy(kdh->versionstring, version, sizeof(kdh->versionstring));
723 	if (panicstr != NULL)
724 		strncpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
725 	kdh->parity = kerneldump_parity(kdh);
726 }
727