kern_shutdown.c revision 235404
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: stable/9/sys/kern/kern_shutdown.c 235404 2012-05-13 17:01:32Z avg $");
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
101int debugger_on_panic = 0;
102#else
103int debugger_on_panic = 1;
104#endif
105SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
106	&debugger_on_panic, 0, "Run debugger on kernel panic");
107TUNABLE_INT("debug.debugger_on_panic", &debugger_on_panic);
108
109#ifdef KDB_TRACE
110static int trace_on_panic = 1;
111#else
112static int trace_on_panic = 0;
113#endif
114SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
115	&trace_on_panic, 0, "Print stack trace on kernel panic");
116TUNABLE_INT("debug.trace_on_panic", &trace_on_panic);
117#endif /* KDB */
118
119static int sync_on_panic = 0;
120SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
121	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
122TUNABLE_INT("kern.sync_on_panic", &sync_on_panic);
123
124static int stop_scheduler_on_panic = 0;
125SYSCTL_INT(_kern, OID_AUTO, stop_scheduler_on_panic, CTLFLAG_RW | CTLFLAG_TUN,
126    &stop_scheduler_on_panic, 0, "stop scheduler upon entering panic");
127TUNABLE_INT("kern.stop_scheduler_on_panic", &stop_scheduler_on_panic);
128
129SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
130
131#ifndef DIAGNOSTIC
132static int show_busybufs;
133#else
134static int show_busybufs = 1;
135#endif
136SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
137	&show_busybufs, 0, "");
138
139/*
140 * Variable panicstr contains argument to first call to panic; used as flag
141 * to indicate that the kernel has already called panic.
142 */
143const char *panicstr;
144
145int stop_scheduler;			/* system stopped CPUs for panic */
146int dumping;				/* system is dumping */
147int rebooting;				/* system is rebooting */
148static struct dumperinfo dumper;	/* our selected dumper */
149
150/* Context information for dump-debuggers. */
151static struct pcb dumppcb;		/* Registers. */
152static lwpid_t dumptid;			/* Thread ID. */
153
154static void poweroff_wait(void *, int);
155static void shutdown_halt(void *junk, int howto);
156static void shutdown_panic(void *junk, int howto);
157static void shutdown_reset(void *junk, int howto);
158
159/* register various local shutdown events */
160static void
161shutdown_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
174SYSINIT(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 */
180int
181sys_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 */
202static int shutdown_howto = 0;
203
204void
205shutdown_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}
221static int	waittime = -1;
222
223static void
224print_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
250int
251doadump(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
278static int
279isbufbusy(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 */
291void
292kern_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#ifdef SW_WATCHDOG
336		wdog_kern_pat(WD_LASTVAL);
337#endif
338		sys_sync(curthread, NULL);
339
340		/*
341		 * With soft updates, some buffers that are
342		 * written will be remarked as dirty until other
343		 * buffers are written.
344		 */
345		for (iter = pbusy = 0; iter < 20; iter++) {
346			nbusy = 0;
347			for (bp = &buf[nbuf]; --bp >= buf; )
348				if (isbufbusy(bp))
349					nbusy++;
350			if (nbusy == 0) {
351				if (first_buf_printf)
352					printf("All buffers synced.");
353				break;
354			}
355			if (first_buf_printf) {
356				printf("Syncing disks, buffers remaining... ");
357				first_buf_printf = 0;
358			}
359			printf("%d ", nbusy);
360			if (nbusy < pbusy)
361				iter = 0;
362			pbusy = nbusy;
363#ifdef SW_WATCHDOG
364			wdog_kern_pat(WD_LASTVAL);
365#endif
366			sys_sync(curthread, NULL);
367
368#ifdef PREEMPTION
369			/*
370			 * Drop Giant and spin for a while to allow
371			 * interrupt threads to run.
372			 */
373			DROP_GIANT();
374			DELAY(50000 * iter);
375			PICKUP_GIANT();
376#else
377			/*
378			 * Drop Giant and context switch several times to
379			 * allow interrupt threads to run.
380			 */
381			DROP_GIANT();
382			for (subiter = 0; subiter < 50 * iter; subiter++) {
383				thread_lock(curthread);
384				mi_switch(SW_VOL, NULL);
385				thread_unlock(curthread);
386				DELAY(1000);
387			}
388			PICKUP_GIANT();
389#endif
390		}
391		printf("\n");
392		/*
393		 * Count only busy local buffers to prevent forcing
394		 * a fsck if we're just a client of a wedged NFS server
395		 */
396		nbusy = 0;
397		for (bp = &buf[nbuf]; --bp >= buf; ) {
398			if (isbufbusy(bp)) {
399#if 0
400/* XXX: This is bogus.  We should probably have a BO_REMOTE flag instead */
401				if (bp->b_dev == NULL) {
402					TAILQ_REMOVE(&mountlist,
403					    bp->b_vp->v_mount, mnt_list);
404					continue;
405				}
406#endif
407				nbusy++;
408				if (show_busybufs > 0) {
409					printf(
410	    "%d: buf:%p, vnode:%p, flags:%0x, blkno:%jd, lblkno:%jd, buflock:",
411					    nbusy, bp, bp->b_vp, bp->b_flags,
412					    (intmax_t)bp->b_blkno,
413					    (intmax_t)bp->b_lblkno);
414					BUF_LOCKPRINTINFO(bp);
415					if (show_busybufs > 1)
416						vn_printf(bp->b_vp,
417						    "vnode content: ");
418				}
419			}
420		}
421		if (nbusy) {
422			/*
423			 * Failed to sync all blocks. Indicate this and don't
424			 * unmount filesystems (thus forcing an fsck on reboot).
425			 */
426			printf("Giving up on %d buffers\n", nbusy);
427			DELAY(5000000);	/* 5 seconds */
428		} else {
429			if (!first_buf_printf)
430				printf("Final sync complete\n");
431			/*
432			 * Unmount filesystems
433			 */
434			if (panicstr == 0)
435				vfs_unmountall();
436		}
437		swapoff_all();
438		DELAY(100000);		/* wait for console output to finish */
439	}
440
441	print_uptime();
442
443	/*
444	 * Ok, now do things that assume all filesystem activity has
445	 * been completed.
446	 */
447	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
448
449	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
450		doadump(TRUE);
451
452	/* Now that we're going to really halt the system... */
453	EVENTHANDLER_INVOKE(shutdown_final, howto);
454
455	for(;;) ;	/* safety against shutdown_reset not working */
456	/* NOTREACHED */
457}
458
459/*
460 * If the shutdown was a clean halt, behave accordingly.
461 */
462static void
463shutdown_halt(void *junk, int howto)
464{
465
466	if (howto & RB_HALT) {
467		printf("\n");
468		printf("The operating system has halted.\n");
469		printf("Please press any key to reboot.\n\n");
470		switch (cngetc()) {
471		case -1:		/* No console, just die */
472			cpu_halt();
473			/* NOTREACHED */
474		default:
475			howto &= ~RB_HALT;
476			break;
477		}
478	}
479}
480
481/*
482 * Check to see if the system paniced, pause and then reboot
483 * according to the specified delay.
484 */
485static void
486shutdown_panic(void *junk, int howto)
487{
488	int loop;
489
490	if (howto & RB_DUMP) {
491		if (PANIC_REBOOT_WAIT_TIME != 0) {
492			if (PANIC_REBOOT_WAIT_TIME != -1) {
493				printf("Automatic reboot in %d seconds - "
494				       "press a key on the console to abort\n",
495					PANIC_REBOOT_WAIT_TIME);
496				for (loop = PANIC_REBOOT_WAIT_TIME * 10;
497				     loop > 0; --loop) {
498					DELAY(1000 * 100); /* 1/10th second */
499					/* Did user type a key? */
500					if (cncheckc() != -1)
501						break;
502				}
503				if (!loop)
504					return;
505			}
506		} else { /* zero time specified - reboot NOW */
507			return;
508		}
509		printf("--> Press a key on the console to reboot,\n");
510		printf("--> or switch off the system now.\n");
511		cngetc();
512	}
513}
514
515/*
516 * Everything done, now reset
517 */
518static void
519shutdown_reset(void *junk, int howto)
520{
521
522	printf("Rebooting...\n");
523	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
524
525	/*
526	 * Acquiring smp_ipi_mtx here has a double effect:
527	 * - it disables interrupts avoiding CPU0 preemption
528	 *   by fast handlers (thus deadlocking  against other CPUs)
529	 * - it avoids deadlocks against smp_rendezvous() or, more
530	 *   generally, threads busy-waiting, with this spinlock held,
531	 *   and waiting for responses by threads on other CPUs
532	 *   (ie. smp_tlb_shootdown()).
533	 *
534	 * For the !SMP case it just needs to handle the former problem.
535	 */
536#ifdef SMP
537	mtx_lock_spin(&smp_ipi_mtx);
538#else
539	spinlock_enter();
540#endif
541
542	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
543	cpu_reset();
544	/* NOTREACHED */ /* assuming reset worked */
545}
546
547/*
548 * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
549 * and then reboots.  If we are called twice, then we avoid trying to sync
550 * the disks as this often leads to recursive panics.
551 */
552void
553panic(const char *fmt, ...)
554{
555#ifdef SMP
556	static volatile u_int panic_cpu = NOCPU;
557	cpuset_t other_cpus;
558#endif
559	struct thread *td = curthread;
560	int bootopt, newpanic;
561	va_list ap;
562	static char buf[256];
563
564	if (stop_scheduler_on_panic)
565		spinlock_enter();
566	else
567		critical_enter();
568
569#ifdef SMP
570	/*
571	 * We don't want multiple CPU's to panic at the same time, so we
572	 * use panic_cpu as a simple spinlock.  We have to keep checking
573	 * panic_cpu if we are spinning in case the panic on the first
574	 * CPU is canceled.
575	 */
576	if (panic_cpu != PCPU_GET(cpuid))
577		while (atomic_cmpset_int(&panic_cpu, NOCPU,
578		    PCPU_GET(cpuid)) == 0)
579			while (panic_cpu != NOCPU)
580				; /* nothing */
581
582	if (stop_scheduler_on_panic) {
583		if (panicstr == NULL && !kdb_active) {
584			other_cpus = all_cpus;
585			CPU_CLR(PCPU_GET(cpuid), &other_cpus);
586			stop_cpus_hard(other_cpus);
587		}
588
589		/*
590		 * We set stop_scheduler here and not in the block above,
591		 * because we want to ensure that if panic has been called and
592		 * stop_scheduler_on_panic is true, then stop_scheduler will
593		 * always be set.  Even if panic has been entered from kdb.
594		 */
595		stop_scheduler = 1;
596	}
597#endif
598
599	bootopt = RB_AUTOBOOT;
600	newpanic = 0;
601	if (panicstr)
602		bootopt |= RB_NOSYNC;
603	else {
604		bootopt |= RB_DUMP;
605		panicstr = fmt;
606		newpanic = 1;
607	}
608
609	va_start(ap, fmt);
610	if (newpanic) {
611		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
612		panicstr = buf;
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
650static int poweroff_delay = POWEROFF_DELAY;
651
652SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
653	&poweroff_delay, 0, "");
654
655static void
656poweroff_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 */
671static int kproc_shutdown_wait = 60;
672SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
673    &kproc_shutdown_wait, 0, "");
674
675void
676kproc_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
695void
696kthread_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 */
716int
717set_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. */
731int
732dump_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
747void
748mkdumpheader(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