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/11/sys/kern/kern_shutdown.c 352719 2019-09-25 19:51:58Z 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/filedesc.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/ktr.h>
60#include <sys/malloc.h>
61#include <sys/mount.h>
62#include <sys/priv.h>
63#include <sys/proc.h>
64#include <sys/reboot.h>
65#include <sys/resourcevar.h>
66#include <sys/rwlock.h>
67#include <sys/sched.h>
68#include <sys/smp.h>
69#include <sys/sysctl.h>
70#include <sys/sysproto.h>
71#include <sys/taskqueue.h>
72#include <sys/vnode.h>
73#include <sys/watchdog.h>
74
75#include <ddb/ddb.h>
76
77#include <machine/cpu.h>
78#include <machine/dump.h>
79#include <machine/pcb.h>
80#include <machine/smp.h>
81
82#include <security/mac/mac_framework.h>
83
84#include <vm/vm.h>
85#include <vm/vm_object.h>
86#include <vm/vm_page.h>
87#include <vm/vm_pager.h>
88#include <vm/swap_pager.h>
89
90#include <sys/signalvar.h>
91
92static MALLOC_DEFINE(M_DUMPER, "dumper", "dumper block buffer");
93
94#ifndef PANIC_REBOOT_WAIT_TIME
95#define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
96#endif
97static int panic_reboot_wait_time = PANIC_REBOOT_WAIT_TIME;
98SYSCTL_INT(_kern, OID_AUTO, panic_reboot_wait_time, CTLFLAG_RWTUN,
99    &panic_reboot_wait_time, 0,
100    "Seconds to wait before rebooting after a panic");
101
102/*
103 * Note that stdarg.h and the ANSI style va_start macro is used for both
104 * ANSI and traditional C compilers.
105 */
106#include <machine/stdarg.h>
107
108#ifdef KDB
109#ifdef KDB_UNATTENDED
110static int debugger_on_panic = 0;
111#else
112static int debugger_on_panic = 1;
113#endif
114SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
115    CTLFLAG_RWTUN | CTLFLAG_SECURE,
116    &debugger_on_panic, 0, "Run debugger on kernel panic");
117
118int debugger_on_trap = 0;
119SYSCTL_INT(_debug, OID_AUTO, debugger_on_trap,
120    CTLFLAG_RWTUN | CTLFLAG_SECURE,
121    &debugger_on_trap, 0, "Run debugger on kernel trap before panic");
122
123#ifdef KDB_TRACE
124static int trace_on_panic = 1;
125#else
126static int trace_on_panic = 0;
127#endif
128SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
129    CTLFLAG_RWTUN | CTLFLAG_SECURE,
130    &trace_on_panic, 0, "Print stack trace on kernel panic");
131#endif /* KDB */
132
133static int sync_on_panic = 0;
134SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RWTUN,
135	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
136
137static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
138    "Shutdown environment");
139
140#ifndef DIAGNOSTIC
141static int show_busybufs;
142#else
143static int show_busybufs = 1;
144#endif
145SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
146	&show_busybufs, 0, "");
147
148int suspend_blocked = 0;
149SYSCTL_INT(_kern, OID_AUTO, suspend_blocked, CTLFLAG_RW,
150	&suspend_blocked, 0, "Block suspend due to a pending shutdown");
151
152/*
153 * Variable panicstr contains argument to first call to panic; used as flag
154 * to indicate that the kernel has already called panic.
155 */
156const char *panicstr;
157
158int dumping;				/* system is dumping */
159int rebooting;				/* system is rebooting */
160static struct dumperinfo dumper;	/* our selected dumper */
161
162/* Context information for dump-debuggers. */
163static struct pcb dumppcb;		/* Registers. */
164lwpid_t dumptid;			/* Thread ID. */
165
166static struct cdevsw reroot_cdevsw = {
167     .d_version = D_VERSION,
168     .d_name    = "reroot",
169};
170
171static void poweroff_wait(void *, int);
172static void shutdown_halt(void *junk, int howto);
173static void shutdown_panic(void *junk, int howto);
174static void shutdown_reset(void *junk, int howto);
175static int kern_reroot(void);
176
177/* register various local shutdown events */
178static void
179shutdown_conf(void *unused)
180{
181
182	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
183	    SHUTDOWN_PRI_FIRST);
184	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
185	    SHUTDOWN_PRI_LAST + 100);
186	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
187	    SHUTDOWN_PRI_LAST + 100);
188	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
189	    SHUTDOWN_PRI_LAST + 200);
190}
191
192SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
193
194/*
195 * The only reason this exists is to create the /dev/reroot/ directory,
196 * used by reroot code in init(8) as a mountpoint for tmpfs.
197 */
198static void
199reroot_conf(void *unused)
200{
201	int error;
202	struct cdev *cdev;
203
204	error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &cdev,
205	    &reroot_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "reroot/reroot");
206	if (error != 0) {
207		printf("%s: failed to create device node, error %d",
208		    __func__, error);
209	}
210}
211
212SYSINIT(reroot_conf, SI_SUB_DEVFS, SI_ORDER_ANY, reroot_conf, NULL);
213
214/*
215 * The system call that results in a reboot.
216 */
217/* ARGSUSED */
218int
219sys_reboot(struct thread *td, struct reboot_args *uap)
220{
221	int error;
222
223	error = 0;
224#ifdef MAC
225	error = mac_system_check_reboot(td->td_ucred, uap->opt);
226#endif
227	if (error == 0)
228		error = priv_check(td, PRIV_REBOOT);
229	if (error == 0) {
230		if (uap->opt & RB_REROOT) {
231			error = kern_reroot();
232		} else {
233			mtx_lock(&Giant);
234			kern_reboot(uap->opt);
235			mtx_unlock(&Giant);
236		}
237	}
238	return (error);
239}
240
241static void
242shutdown_nice_task_fn(void *arg, int pending __unused)
243{
244	int howto;
245
246	howto = (uintptr_t)arg;
247	/* Send a signal to init(8) and have it shutdown the world. */
248	PROC_LOCK(initproc);
249	if (howto & RB_POWEROFF)
250		kern_psignal(initproc, SIGUSR2);
251	else if (howto & RB_HALT)
252		kern_psignal(initproc, SIGUSR1);
253	else
254		kern_psignal(initproc, SIGINT);
255	PROC_UNLOCK(initproc);
256}
257
258static struct task shutdown_nice_task = TASK_INITIALIZER(0,
259    &shutdown_nice_task_fn, NULL);
260
261/*
262 * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
263 */
264void
265shutdown_nice(int howto)
266{
267
268	if (initproc != NULL && !SCHEDULER_STOPPED()) {
269		shutdown_nice_task.ta_context = (void *)(uintptr_t)howto;
270		taskqueue_enqueue(taskqueue_fast, &shutdown_nice_task);
271	} else {
272		/*
273		 * No init(8) running, or scheduler would not allow it
274		 * to run, so simply reboot.
275		 */
276		kern_reboot(howto | RB_NOSYNC);
277	}
278}
279
280static void
281print_uptime(void)
282{
283	int f;
284	struct timespec ts;
285
286	getnanouptime(&ts);
287	printf("Uptime: ");
288	f = 0;
289	if (ts.tv_sec >= 86400) {
290		printf("%ldd", (long)ts.tv_sec / 86400);
291		ts.tv_sec %= 86400;
292		f = 1;
293	}
294	if (f || ts.tv_sec >= 3600) {
295		printf("%ldh", (long)ts.tv_sec / 3600);
296		ts.tv_sec %= 3600;
297		f = 1;
298	}
299	if (f || ts.tv_sec >= 60) {
300		printf("%ldm", (long)ts.tv_sec / 60);
301		ts.tv_sec %= 60;
302		f = 1;
303	}
304	printf("%lds\n", (long)ts.tv_sec);
305}
306
307int
308doadump(boolean_t textdump)
309{
310	boolean_t coredump;
311	int error;
312
313	error = 0;
314	if (dumping)
315		return (EBUSY);
316	if (dumper.dumper == NULL)
317		return (ENXIO);
318
319	savectx(&dumppcb);
320	dumptid = curthread->td_tid;
321	dumping++;
322
323	coredump = TRUE;
324#ifdef DDB
325	if (textdump && textdump_pending) {
326		coredump = FALSE;
327		textdump_dumpsys(&dumper);
328	}
329#endif
330	if (coredump)
331		error = dumpsys(&dumper);
332
333	dumping--;
334	return (error);
335}
336
337/*
338 * Shutdown the system cleanly to prepare for reboot, halt, or power off.
339 */
340void
341kern_reboot(int howto)
342{
343	static int once = 0;
344
345#if defined(SMP)
346	/*
347	 * Bind us to CPU 0 so that all shutdown code runs there.  Some
348	 * systems don't shutdown properly (i.e., ACPI power off) if we
349	 * run on another processor.
350	 */
351	if (!SCHEDULER_STOPPED()) {
352		thread_lock(curthread);
353		sched_bind(curthread, 0);
354		thread_unlock(curthread);
355		KASSERT(PCPU_GET(cpuid) == 0, ("boot: not running on cpu 0"));
356	}
357#endif
358	/* We're in the process of rebooting. */
359	rebooting = 1;
360
361	/* We are out of the debugger now. */
362	kdb_active = 0;
363
364	/*
365	 * Do any callouts that should be done BEFORE syncing the filesystems.
366	 */
367	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
368
369	/*
370	 * Now sync filesystems
371	 */
372	if (!cold && (howto & RB_NOSYNC) == 0 && once == 0) {
373		once = 1;
374		bufshutdown(show_busybufs);
375	}
376
377	print_uptime();
378
379	cngrab();
380
381	/*
382	 * Ok, now do things that assume all filesystem activity has
383	 * been completed.
384	 */
385	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
386
387	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
388		doadump(TRUE);
389
390	/* Now that we're going to really halt the system... */
391	EVENTHANDLER_INVOKE(shutdown_final, howto);
392
393	for(;;) ;	/* safety against shutdown_reset not working */
394	/* NOTREACHED */
395}
396
397/*
398 * The system call that results in changing the rootfs.
399 */
400static int
401kern_reroot(void)
402{
403	struct vnode *oldrootvnode, *vp;
404	struct mount *mp, *devmp;
405	int error;
406
407	if (curproc != initproc)
408		return (EPERM);
409
410	/*
411	 * Mark the filesystem containing currently-running executable
412	 * (the temporary copy of init(8)) busy.
413	 */
414	vp = curproc->p_textvp;
415	error = vn_lock(vp, LK_SHARED);
416	if (error != 0)
417		return (error);
418	mp = vp->v_mount;
419	error = vfs_busy(mp, MBF_NOWAIT);
420	if (error != 0) {
421		vfs_ref(mp);
422		VOP_UNLOCK(vp, 0);
423		error = vfs_busy(mp, 0);
424		vn_lock(vp, LK_SHARED | LK_RETRY);
425		vfs_rel(mp);
426		if (error != 0) {
427			VOP_UNLOCK(vp, 0);
428			return (ENOENT);
429		}
430		if (vp->v_iflag & VI_DOOMED) {
431			VOP_UNLOCK(vp, 0);
432			vfs_unbusy(mp);
433			return (ENOENT);
434		}
435	}
436	VOP_UNLOCK(vp, 0);
437
438	/*
439	 * Remove the filesystem containing currently-running executable
440	 * from the mount list, to prevent it from being unmounted
441	 * by vfs_unmountall(), and to avoid confusing vfs_mountroot().
442	 *
443	 * Also preserve /dev - forcibly unmounting it could cause driver
444	 * reinitialization.
445	 */
446
447	vfs_ref(rootdevmp);
448	devmp = rootdevmp;
449	rootdevmp = NULL;
450
451	mtx_lock(&mountlist_mtx);
452	TAILQ_REMOVE(&mountlist, mp, mnt_list);
453	TAILQ_REMOVE(&mountlist, devmp, mnt_list);
454	mtx_unlock(&mountlist_mtx);
455
456	oldrootvnode = rootvnode;
457
458	/*
459	 * Unmount everything except for the two filesystems preserved above.
460	 */
461	vfs_unmountall();
462
463	/*
464	 * Add /dev back; vfs_mountroot() will move it into its new place.
465	 */
466	mtx_lock(&mountlist_mtx);
467	TAILQ_INSERT_HEAD(&mountlist, devmp, mnt_list);
468	mtx_unlock(&mountlist_mtx);
469	rootdevmp = devmp;
470	vfs_rel(rootdevmp);
471
472	/*
473	 * Mount the new rootfs.
474	 */
475	vfs_mountroot();
476
477	/*
478	 * Update all references to the old rootvnode.
479	 */
480	mountcheckdirs(oldrootvnode, rootvnode);
481
482	/*
483	 * Add the temporary filesystem back and unbusy it.
484	 */
485	mtx_lock(&mountlist_mtx);
486	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
487	mtx_unlock(&mountlist_mtx);
488	vfs_unbusy(mp);
489
490	return (0);
491}
492
493/*
494 * If the shutdown was a clean halt, behave accordingly.
495 */
496static void
497shutdown_halt(void *junk, int howto)
498{
499
500	if (howto & RB_HALT) {
501		printf("\n");
502		printf("The operating system has halted.\n");
503		printf("Please press any key to reboot.\n\n");
504
505		wdog_kern_pat(WD_TO_NEVER);
506
507		switch (cngetc()) {
508		case -1:		/* No console, just die */
509			cpu_halt();
510			/* NOTREACHED */
511		default:
512			howto &= ~RB_HALT;
513			break;
514		}
515	}
516}
517
518/*
519 * Check to see if the system paniced, pause and then reboot
520 * according to the specified delay.
521 */
522static void
523shutdown_panic(void *junk, int howto)
524{
525	int loop;
526
527	if (howto & RB_DUMP) {
528		if (panic_reboot_wait_time != 0) {
529			if (panic_reboot_wait_time != -1) {
530				printf("Automatic reboot in %d seconds - "
531				       "press a key on the console to abort\n",
532					panic_reboot_wait_time);
533				for (loop = panic_reboot_wait_time * 10;
534				     loop > 0; --loop) {
535					DELAY(1000 * 100); /* 1/10th second */
536					/* Did user type a key? */
537					if (cncheckc() != -1)
538						break;
539				}
540				if (!loop)
541					return;
542			}
543		} else { /* zero time specified - reboot NOW */
544			return;
545		}
546		printf("--> Press a key on the console to reboot,\n");
547		printf("--> or switch off the system now.\n");
548		cngetc();
549	}
550}
551
552/*
553 * Everything done, now reset
554 */
555static void
556shutdown_reset(void *junk, int howto)
557{
558
559	printf("Rebooting...\n");
560	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
561
562	/*
563	 * Acquiring smp_ipi_mtx here has a double effect:
564	 * - it disables interrupts avoiding CPU0 preemption
565	 *   by fast handlers (thus deadlocking  against other CPUs)
566	 * - it avoids deadlocks against smp_rendezvous() or, more
567	 *   generally, threads busy-waiting, with this spinlock held,
568	 *   and waiting for responses by threads on other CPUs
569	 *   (ie. smp_tlb_shootdown()).
570	 *
571	 * For the !SMP case it just needs to handle the former problem.
572	 */
573#ifdef SMP
574	mtx_lock_spin(&smp_ipi_mtx);
575#else
576	spinlock_enter();
577#endif
578
579	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
580	cpu_reset();
581	/* NOTREACHED */ /* assuming reset worked */
582}
583
584#if defined(WITNESS) || defined(INVARIANT_SUPPORT)
585static int kassert_warn_only = 0;
586#ifdef KDB
587static int kassert_do_kdb = 0;
588#endif
589#ifdef KTR
590static int kassert_do_ktr = 0;
591#endif
592static int kassert_do_log = 1;
593static int kassert_log_pps_limit = 4;
594static int kassert_log_mute_at = 0;
595static int kassert_log_panic_at = 0;
596static int kassert_warnings = 0;
597
598SYSCTL_NODE(_debug, OID_AUTO, kassert, CTLFLAG_RW, NULL, "kassert options");
599
600SYSCTL_INT(_debug_kassert, OID_AUTO, warn_only, CTLFLAG_RWTUN,
601    &kassert_warn_only, 0,
602    "KASSERT triggers a panic (1) or just a warning (0)");
603
604#ifdef KDB
605SYSCTL_INT(_debug_kassert, OID_AUTO, do_kdb, CTLFLAG_RWTUN,
606    &kassert_do_kdb, 0, "KASSERT will enter the debugger");
607#endif
608
609#ifdef KTR
610SYSCTL_UINT(_debug_kassert, OID_AUTO, do_ktr, CTLFLAG_RWTUN,
611    &kassert_do_ktr, 0,
612    "KASSERT does a KTR, set this to the KTRMASK you want");
613#endif
614
615SYSCTL_INT(_debug_kassert, OID_AUTO, do_log, CTLFLAG_RWTUN,
616    &kassert_do_log, 0, "KASSERT triggers a panic (1) or just a warning (0)");
617
618SYSCTL_INT(_debug_kassert, OID_AUTO, warnings, CTLFLAG_RWTUN,
619    &kassert_warnings, 0, "number of KASSERTs that have been triggered");
620
621SYSCTL_INT(_debug_kassert, OID_AUTO, log_panic_at, CTLFLAG_RWTUN,
622    &kassert_log_panic_at, 0, "max number of KASSERTS before we will panic");
623
624SYSCTL_INT(_debug_kassert, OID_AUTO, log_pps_limit, CTLFLAG_RWTUN,
625    &kassert_log_pps_limit, 0, "limit number of log messages per second");
626
627SYSCTL_INT(_debug_kassert, OID_AUTO, log_mute_at, CTLFLAG_RWTUN,
628    &kassert_log_mute_at, 0, "max number of KASSERTS to log");
629
630static int kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS);
631
632SYSCTL_PROC(_debug_kassert, OID_AUTO, kassert,
633    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0,
634    kassert_sysctl_kassert, "I", "set to trigger a test kassert");
635
636static int
637kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS)
638{
639	int error, i;
640
641	error = sysctl_wire_old_buffer(req, sizeof(int));
642	if (error == 0) {
643		i = 0;
644		error = sysctl_handle_int(oidp, &i, 0, req);
645	}
646	if (error != 0 || req->newptr == NULL)
647		return (error);
648	KASSERT(0, ("kassert_sysctl_kassert triggered kassert %d", i));
649	return (0);
650}
651
652/*
653 * Called by KASSERT, this decides if we will panic
654 * or if we will log via printf and/or ktr.
655 */
656void
657kassert_panic(const char *fmt, ...)
658{
659	static char buf[256];
660	va_list ap;
661
662	va_start(ap, fmt);
663	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
664	va_end(ap);
665
666	/*
667	 * panic if we're not just warning, or if we've exceeded
668	 * kassert_log_panic_at warnings.
669	 */
670	if (!kassert_warn_only ||
671	    (kassert_log_panic_at > 0 &&
672	     kassert_warnings >= kassert_log_panic_at)) {
673		va_start(ap, fmt);
674		vpanic(fmt, ap);
675		/* NORETURN */
676	}
677#ifdef KTR
678	if (kassert_do_ktr)
679		CTR0(ktr_mask, buf);
680#endif /* KTR */
681	/*
682	 * log if we've not yet met the mute limit.
683	 */
684	if (kassert_do_log &&
685	    (kassert_log_mute_at == 0 ||
686	     kassert_warnings < kassert_log_mute_at)) {
687		static  struct timeval lasterr;
688		static  int curerr;
689
690		if (ppsratecheck(&lasterr, &curerr, kassert_log_pps_limit)) {
691			printf("KASSERT failed: %s\n", buf);
692			kdb_backtrace();
693		}
694	}
695#ifdef KDB
696	if (kassert_do_kdb) {
697		kdb_enter(KDB_WHY_KASSERT, buf);
698	}
699#endif
700	atomic_add_int(&kassert_warnings, 1);
701}
702#endif
703
704/*
705 * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
706 * and then reboots.  If we are called twice, then we avoid trying to sync
707 * the disks as this often leads to recursive panics.
708 */
709void
710panic(const char *fmt, ...)
711{
712	va_list ap;
713
714	va_start(ap, fmt);
715	vpanic(fmt, ap);
716}
717
718void
719vpanic(const char *fmt, va_list ap)
720{
721#ifdef SMP
722	cpuset_t other_cpus;
723#endif
724	struct thread *td = curthread;
725	int bootopt, newpanic;
726	static char buf[256];
727
728	spinlock_enter();
729
730#ifdef SMP
731	/*
732	 * stop_cpus_hard(other_cpus) should prevent multiple CPUs from
733	 * concurrently entering panic.  Only the winner will proceed
734	 * further.
735	 */
736	if (panicstr == NULL && !kdb_active) {
737		other_cpus = all_cpus;
738		CPU_CLR(PCPU_GET(cpuid), &other_cpus);
739		stop_cpus_hard(other_cpus);
740	}
741#endif
742
743	/*
744	 * Ensure that the scheduler is stopped while panicking, even if panic
745	 * has been entered from kdb.
746	 */
747	td->td_stopsched = 1;
748
749	bootopt = RB_AUTOBOOT;
750	newpanic = 0;
751	if (panicstr)
752		bootopt |= RB_NOSYNC;
753	else {
754		bootopt |= RB_DUMP;
755		panicstr = fmt;
756		newpanic = 1;
757	}
758
759	if (newpanic) {
760		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
761		panicstr = buf;
762		cngrab();
763		printf("panic: %s\n", buf);
764	} else {
765		printf("panic: ");
766		vprintf(fmt, ap);
767		printf("\n");
768	}
769#ifdef SMP
770	printf("cpuid = %d\n", PCPU_GET(cpuid));
771#endif
772
773#ifdef KDB
774	if (newpanic && trace_on_panic)
775		kdb_backtrace();
776	if (debugger_on_panic)
777		kdb_enter(KDB_WHY_PANIC, "panic");
778#endif
779	/*thread_lock(td); */
780	td->td_flags |= TDF_INPANIC;
781	/* thread_unlock(td); */
782	if (!sync_on_panic)
783		bootopt |= RB_NOSYNC;
784	kern_reboot(bootopt);
785}
786
787/*
788 * Support for poweroff delay.
789 *
790 * Please note that setting this delay too short might power off your machine
791 * before the write cache on your hard disk has been flushed, leading to
792 * soft-updates inconsistencies.
793 */
794#ifndef POWEROFF_DELAY
795# define POWEROFF_DELAY 5000
796#endif
797static int poweroff_delay = POWEROFF_DELAY;
798
799SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
800    &poweroff_delay, 0, "Delay before poweroff to write disk caches (msec)");
801
802static void
803poweroff_wait(void *junk, int howto)
804{
805
806	if (!(howto & RB_POWEROFF) || poweroff_delay <= 0)
807		return;
808	DELAY(poweroff_delay * 1000);
809}
810
811/*
812 * Some system processes (e.g. syncer) need to be stopped at appropriate
813 * points in their main loops prior to a system shutdown, so that they
814 * won't interfere with the shutdown process (e.g. by holding a disk buf
815 * to cause sync to fail).  For each of these system processes, register
816 * shutdown_kproc() as a handler for one of shutdown events.
817 */
818static int kproc_shutdown_wait = 60;
819SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
820    &kproc_shutdown_wait, 0, "Max wait time (sec) to stop for each process");
821
822void
823kproc_shutdown(void *arg, int howto)
824{
825	struct proc *p;
826	int error;
827
828	if (panicstr)
829		return;
830
831	p = (struct proc *)arg;
832	printf("Waiting (max %d seconds) for system process `%s' to stop... ",
833	    kproc_shutdown_wait, p->p_comm);
834	error = kproc_suspend(p, kproc_shutdown_wait * hz);
835
836	if (error == EWOULDBLOCK)
837		printf("timed out\n");
838	else
839		printf("done\n");
840}
841
842void
843kthread_shutdown(void *arg, int howto)
844{
845	struct thread *td;
846	int error;
847
848	if (panicstr)
849		return;
850
851	td = (struct thread *)arg;
852	printf("Waiting (max %d seconds) for system thread `%s' to stop... ",
853	    kproc_shutdown_wait, td->td_name);
854	error = kthread_suspend(td, kproc_shutdown_wait * hz);
855
856	if (error == EWOULDBLOCK)
857		printf("timed out\n");
858	else
859		printf("done\n");
860}
861
862static char dumpdevname[sizeof(((struct cdev*)NULL)->si_name)];
863SYSCTL_STRING(_kern_shutdown, OID_AUTO, dumpdevname, CTLFLAG_RD,
864    dumpdevname, 0, "Device for kernel dumps");
865
866/* Registration of dumpers */
867int
868set_dumper(struct dumperinfo *di, const char *devname, struct thread *td)
869{
870	size_t wantcopy;
871	int error;
872
873	error = priv_check(td, PRIV_SETDUMPER);
874	if (error != 0)
875		return (error);
876
877	if (di == NULL) {
878		if (dumper.blockbuf != NULL)
879			free(dumper.blockbuf, M_DUMPER);
880		bzero(&dumper, sizeof(dumper));
881		dumpdevname[0] = '\0';
882		return (0);
883	}
884	if (dumper.dumper != NULL)
885		return (EBUSY);
886	dumper = *di;
887	wantcopy = strlcpy(dumpdevname, devname, sizeof(dumpdevname));
888	if (wantcopy >= sizeof(dumpdevname)) {
889		printf("set_dumper: device name truncated from '%s' -> '%s'\n",
890			devname, dumpdevname);
891	}
892	dumper.blockbuf = malloc(di->blocksize, M_DUMPER, M_WAITOK | M_ZERO);
893	return (0);
894}
895
896/* Call dumper with bounds checking. */
897int
898dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
899    off_t offset, size_t length)
900{
901
902	if (length != 0 && (offset < di->mediaoffset ||
903	    offset - di->mediaoffset + length > di->mediasize)) {
904		printf("Attempt to write outside dump device boundaries.\n"
905	    "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
906		    (intmax_t)offset, (intmax_t)di->mediaoffset,
907		    (uintmax_t)length, (intmax_t)di->mediasize);
908		return (ENOSPC);
909	}
910	return (di->dumper(di->priv, virtual, physical, offset, length));
911}
912
913/* Call dumper with bounds checking. */
914int
915dump_write_pad(struct dumperinfo *di, void *virtual, vm_offset_t physical,
916    off_t offset, size_t length, size_t *size)
917{
918	char *temp;
919	int ret;
920
921	if (length > di->blocksize)
922		return (ENOMEM);
923
924	*size = di->blocksize;
925	if (length == di->blocksize)
926		temp = virtual;
927	else {
928		temp = di->blockbuf;
929		memset(temp + length, 0, di->blocksize - length);
930		memcpy(temp, virtual, length);
931	}
932	ret = dump_write(di, temp, physical, offset, *size);
933
934	return (ret);
935}
936
937
938void
939mkdumpheader(struct kerneldumpheader *kdh, char *magic, uint32_t archver,
940    uint64_t dumplen, uint32_t blksz)
941{
942	size_t dstsize;
943
944	bzero(kdh, sizeof(*kdh));
945	strlcpy(kdh->magic, magic, sizeof(kdh->magic));
946	strlcpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
947	kdh->version = htod32(KERNELDUMPVERSION);
948	kdh->architectureversion = htod32(archver);
949	kdh->dumplength = htod64(dumplen);
950	kdh->dumptime = htod64(time_second);
951	kdh->blocksize = htod32(blksz);
952	strlcpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
953	dstsize = sizeof(kdh->versionstring);
954	if (strlcpy(kdh->versionstring, version, dstsize) >= dstsize)
955		kdh->versionstring[dstsize - 2] = '\n';
956	if (panicstr != NULL)
957		strlcpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
958	kdh->parity = kerneldump_parity(kdh);
959}
960
961#ifdef DDB
962DB_SHOW_COMMAND(panic, db_show_panic)
963{
964
965	if (panicstr == NULL)
966		db_printf("panicstr not set\n");
967	else
968		db_printf("panic: %s\n", panicstr);
969}
970#endif
971