xref: /freebsd/sys/kern/kern_shutdown.c (revision daceb336172a6b0572de864b97e70b28451ca636)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1986, 1988, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)kern_shutdown.c	8.3 (Berkeley) 1/21/94
37  */
38 
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include "opt_ddb.h"
43 #include "opt_ekcd.h"
44 #include "opt_kdb.h"
45 #include "opt_panic.h"
46 #include "opt_printf.h"
47 #include "opt_sched.h"
48 #include "opt_watchdog.h"
49 
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/bio.h>
53 #include <sys/buf.h>
54 #include <sys/conf.h>
55 #include <sys/compressor.h>
56 #include <sys/cons.h>
57 #include <sys/disk.h>
58 #include <sys/eventhandler.h>
59 #include <sys/filedesc.h>
60 #include <sys/jail.h>
61 #include <sys/kdb.h>
62 #include <sys/kernel.h>
63 #include <sys/kerneldump.h>
64 #include <sys/kthread.h>
65 #include <sys/ktr.h>
66 #include <sys/malloc.h>
67 #include <sys/mbuf.h>
68 #include <sys/mount.h>
69 #include <sys/priv.h>
70 #include <sys/proc.h>
71 #include <sys/reboot.h>
72 #include <sys/resourcevar.h>
73 #include <sys/rwlock.h>
74 #include <sys/sbuf.h>
75 #include <sys/sched.h>
76 #include <sys/smp.h>
77 #include <sys/sysctl.h>
78 #include <sys/sysproto.h>
79 #include <sys/taskqueue.h>
80 #include <sys/vnode.h>
81 #include <sys/watchdog.h>
82 
83 #include <crypto/rijndael/rijndael-api-fst.h>
84 #include <crypto/sha2/sha256.h>
85 
86 #include <ddb/ddb.h>
87 
88 #include <machine/cpu.h>
89 #include <machine/dump.h>
90 #include <machine/pcb.h>
91 #include <machine/smp.h>
92 
93 #include <security/mac/mac_framework.h>
94 
95 #include <vm/vm.h>
96 #include <vm/vm_object.h>
97 #include <vm/vm_page.h>
98 #include <vm/vm_pager.h>
99 #include <vm/swap_pager.h>
100 
101 #include <sys/signalvar.h>
102 
103 static MALLOC_DEFINE(M_DUMPER, "dumper", "dumper block buffer");
104 
105 #ifndef PANIC_REBOOT_WAIT_TIME
106 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
107 #endif
108 static int panic_reboot_wait_time = PANIC_REBOOT_WAIT_TIME;
109 SYSCTL_INT(_kern, OID_AUTO, panic_reboot_wait_time, CTLFLAG_RWTUN,
110     &panic_reboot_wait_time, 0,
111     "Seconds to wait before rebooting after a panic");
112 
113 /*
114  * Note that stdarg.h and the ANSI style va_start macro is used for both
115  * ANSI and traditional C compilers.
116  */
117 #include <machine/stdarg.h>
118 
119 #ifdef KDB
120 #ifdef KDB_UNATTENDED
121 static int debugger_on_panic = 0;
122 #else
123 static int debugger_on_panic = 1;
124 #endif
125 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
126     CTLFLAG_RWTUN | CTLFLAG_SECURE,
127     &debugger_on_panic, 0, "Run debugger on kernel panic");
128 
129 int debugger_on_trap = 0;
130 SYSCTL_INT(_debug, OID_AUTO, debugger_on_trap,
131     CTLFLAG_RWTUN | CTLFLAG_SECURE,
132     &debugger_on_trap, 0, "Run debugger on kernel trap before panic");
133 
134 #ifdef KDB_TRACE
135 static int trace_on_panic = 1;
136 static bool trace_all_panics = true;
137 #else
138 static int trace_on_panic = 0;
139 static bool trace_all_panics = false;
140 #endif
141 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
142     CTLFLAG_RWTUN | CTLFLAG_SECURE,
143     &trace_on_panic, 0, "Print stack trace on kernel panic");
144 SYSCTL_BOOL(_debug, OID_AUTO, trace_all_panics, CTLFLAG_RWTUN,
145     &trace_all_panics, 0, "Print stack traces on secondary kernel panics");
146 #endif /* KDB */
147 
148 static int sync_on_panic = 0;
149 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RWTUN,
150 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
151 
152 static bool poweroff_on_panic = 0;
153 SYSCTL_BOOL(_kern, OID_AUTO, poweroff_on_panic, CTLFLAG_RWTUN,
154 	&poweroff_on_panic, 0, "Do a power off instead of a reboot on a panic");
155 
156 static bool powercycle_on_panic = 0;
157 SYSCTL_BOOL(_kern, OID_AUTO, powercycle_on_panic, CTLFLAG_RWTUN,
158 	&powercycle_on_panic, 0, "Do a power cycle instead of a reboot on a panic");
159 
160 static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
161     "Shutdown environment");
162 
163 #ifndef DIAGNOSTIC
164 static int show_busybufs;
165 #else
166 static int show_busybufs = 1;
167 #endif
168 SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
169 	&show_busybufs, 0, "");
170 
171 int suspend_blocked = 0;
172 SYSCTL_INT(_kern, OID_AUTO, suspend_blocked, CTLFLAG_RW,
173 	&suspend_blocked, 0, "Block suspend due to a pending shutdown");
174 
175 #ifdef EKCD
176 FEATURE(ekcd, "Encrypted kernel crash dumps support");
177 
178 MALLOC_DEFINE(M_EKCD, "ekcd", "Encrypted kernel crash dumps data");
179 
180 struct kerneldumpcrypto {
181 	uint8_t			kdc_encryption;
182 	uint8_t			kdc_iv[KERNELDUMP_IV_MAX_SIZE];
183 	keyInstance		kdc_ki;
184 	cipherInstance		kdc_ci;
185 	uint32_t		kdc_dumpkeysize;
186 	struct kerneldumpkey	kdc_dumpkey[];
187 };
188 #endif
189 
190 struct kerneldumpcomp {
191 	uint8_t			kdc_format;
192 	struct compressor	*kdc_stream;
193 	uint8_t			*kdc_buf;
194 	size_t			kdc_resid;
195 };
196 
197 static struct kerneldumpcomp *kerneldumpcomp_create(struct dumperinfo *di,
198 		    uint8_t compression);
199 static void	kerneldumpcomp_destroy(struct dumperinfo *di);
200 static int	kerneldumpcomp_write_cb(void *base, size_t len, off_t off, void *arg);
201 
202 static int kerneldump_gzlevel = 6;
203 SYSCTL_INT(_kern, OID_AUTO, kerneldump_gzlevel, CTLFLAG_RWTUN,
204     &kerneldump_gzlevel, 0,
205     "Kernel crash dump compression level");
206 
207 /*
208  * Variable panicstr contains argument to first call to panic; used as flag
209  * to indicate that the kernel has already called panic.
210  */
211 const char *panicstr;
212 
213 int dumping;				/* system is dumping */
214 int rebooting;				/* system is rebooting */
215 /*
216  * Used to serialize between sysctl kern.shutdown.dumpdevname and list
217  * modifications via ioctl.
218  */
219 static struct mtx dumpconf_list_lk;
220 MTX_SYSINIT(dumper_configs, &dumpconf_list_lk, "dumper config list", MTX_DEF);
221 
222 /* Our selected dumper(s). */
223 static TAILQ_HEAD(dumpconflist, dumperinfo) dumper_configs =
224     TAILQ_HEAD_INITIALIZER(dumper_configs);
225 
226 /* Context information for dump-debuggers. */
227 static struct pcb dumppcb;		/* Registers. */
228 lwpid_t dumptid;			/* Thread ID. */
229 
230 static struct cdevsw reroot_cdevsw = {
231      .d_version = D_VERSION,
232      .d_name    = "reroot",
233 };
234 
235 static void poweroff_wait(void *, int);
236 static void shutdown_halt(void *junk, int howto);
237 static void shutdown_panic(void *junk, int howto);
238 static void shutdown_reset(void *junk, int howto);
239 static int kern_reroot(void);
240 
241 /* register various local shutdown events */
242 static void
243 shutdown_conf(void *unused)
244 {
245 
246 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
247 	    SHUTDOWN_PRI_FIRST);
248 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
249 	    SHUTDOWN_PRI_LAST + 100);
250 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
251 	    SHUTDOWN_PRI_LAST + 100);
252 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
253 	    SHUTDOWN_PRI_LAST + 200);
254 }
255 
256 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
257 
258 /*
259  * The only reason this exists is to create the /dev/reroot/ directory,
260  * used by reroot code in init(8) as a mountpoint for tmpfs.
261  */
262 static void
263 reroot_conf(void *unused)
264 {
265 	int error;
266 	struct cdev *cdev;
267 
268 	error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &cdev,
269 	    &reroot_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "reroot/reroot");
270 	if (error != 0) {
271 		printf("%s: failed to create device node, error %d",
272 		    __func__, error);
273 	}
274 }
275 
276 SYSINIT(reroot_conf, SI_SUB_DEVFS, SI_ORDER_ANY, reroot_conf, NULL);
277 
278 /*
279  * The system call that results in a reboot.
280  */
281 /* ARGSUSED */
282 int
283 sys_reboot(struct thread *td, struct reboot_args *uap)
284 {
285 	int error;
286 
287 	error = 0;
288 #ifdef MAC
289 	error = mac_system_check_reboot(td->td_ucred, uap->opt);
290 #endif
291 	if (error == 0)
292 		error = priv_check(td, PRIV_REBOOT);
293 	if (error == 0) {
294 		if (uap->opt & RB_REROOT)
295 			error = kern_reroot();
296 		else
297 			kern_reboot(uap->opt);
298 	}
299 	return (error);
300 }
301 
302 static void
303 shutdown_nice_task_fn(void *arg, int pending __unused)
304 {
305 	int howto;
306 
307 	howto = (uintptr_t)arg;
308 	/* Send a signal to init(8) and have it shutdown the world. */
309 	PROC_LOCK(initproc);
310 	if (howto & RB_POWEROFF)
311 		kern_psignal(initproc, SIGUSR2);
312 	else if (howto & RB_POWERCYCLE)
313 		kern_psignal(initproc, SIGWINCH);
314 	else if (howto & RB_HALT)
315 		kern_psignal(initproc, SIGUSR1);
316 	else
317 		kern_psignal(initproc, SIGINT);
318 	PROC_UNLOCK(initproc);
319 }
320 
321 static struct task shutdown_nice_task = TASK_INITIALIZER(0,
322     &shutdown_nice_task_fn, NULL);
323 
324 /*
325  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
326  */
327 void
328 shutdown_nice(int howto)
329 {
330 
331 	if (initproc != NULL && !SCHEDULER_STOPPED()) {
332 		shutdown_nice_task.ta_context = (void *)(uintptr_t)howto;
333 		taskqueue_enqueue(taskqueue_fast, &shutdown_nice_task);
334 	} else {
335 		/*
336 		 * No init(8) running, or scheduler would not allow it
337 		 * to run, so simply reboot.
338 		 */
339 		kern_reboot(howto | RB_NOSYNC);
340 	}
341 }
342 
343 static void
344 print_uptime(void)
345 {
346 	int f;
347 	struct timespec ts;
348 
349 	getnanouptime(&ts);
350 	printf("Uptime: ");
351 	f = 0;
352 	if (ts.tv_sec >= 86400) {
353 		printf("%ldd", (long)ts.tv_sec / 86400);
354 		ts.tv_sec %= 86400;
355 		f = 1;
356 	}
357 	if (f || ts.tv_sec >= 3600) {
358 		printf("%ldh", (long)ts.tv_sec / 3600);
359 		ts.tv_sec %= 3600;
360 		f = 1;
361 	}
362 	if (f || ts.tv_sec >= 60) {
363 		printf("%ldm", (long)ts.tv_sec / 60);
364 		ts.tv_sec %= 60;
365 		f = 1;
366 	}
367 	printf("%lds\n", (long)ts.tv_sec);
368 }
369 
370 int
371 doadump(boolean_t textdump)
372 {
373 	boolean_t coredump;
374 	int error;
375 
376 	error = 0;
377 	if (dumping)
378 		return (EBUSY);
379 	if (TAILQ_EMPTY(&dumper_configs))
380 		return (ENXIO);
381 
382 	savectx(&dumppcb);
383 	dumptid = curthread->td_tid;
384 	dumping++;
385 
386 	coredump = TRUE;
387 #ifdef DDB
388 	if (textdump && textdump_pending) {
389 		coredump = FALSE;
390 		textdump_dumpsys(TAILQ_FIRST(&dumper_configs));
391 	}
392 #endif
393 	if (coredump) {
394 		struct dumperinfo *di;
395 
396 		TAILQ_FOREACH(di, &dumper_configs, di_next) {
397 			error = dumpsys(di);
398 			if (error == 0)
399 				break;
400 		}
401 	}
402 
403 	dumping--;
404 	return (error);
405 }
406 
407 /*
408  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
409  */
410 void
411 kern_reboot(int howto)
412 {
413 	static int once = 0;
414 
415 	/*
416 	 * Normal paths here don't hold Giant, but we can wind up here
417 	 * unexpectedly with it held.  Drop it now so we don't have to
418 	 * drop and pick it up elsewhere. The paths it is locking will
419 	 * never be returned to, and it is preferable to preclude
420 	 * deadlock than to lock against code that won't ever
421 	 * continue.
422 	 */
423 	while (mtx_owned(&Giant))
424 		mtx_unlock(&Giant);
425 
426 #if defined(SMP)
427 	/*
428 	 * Bind us to the first CPU so that all shutdown code runs there.  Some
429 	 * systems don't shutdown properly (i.e., ACPI power off) if we
430 	 * run on another processor.
431 	 */
432 	if (!SCHEDULER_STOPPED()) {
433 		thread_lock(curthread);
434 		sched_bind(curthread, CPU_FIRST());
435 		thread_unlock(curthread);
436 		KASSERT(PCPU_GET(cpuid) == CPU_FIRST(),
437 		    ("boot: not running on cpu 0"));
438 	}
439 #endif
440 	/* We're in the process of rebooting. */
441 	rebooting = 1;
442 
443 	/* We are out of the debugger now. */
444 	kdb_active = 0;
445 
446 	/*
447 	 * Do any callouts that should be done BEFORE syncing the filesystems.
448 	 */
449 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
450 
451 	/*
452 	 * Now sync filesystems
453 	 */
454 	if (!cold && (howto & RB_NOSYNC) == 0 && once == 0) {
455 		once = 1;
456 		bufshutdown(show_busybufs);
457 	}
458 
459 	print_uptime();
460 
461 	cngrab();
462 
463 	/*
464 	 * Ok, now do things that assume all filesystem activity has
465 	 * been completed.
466 	 */
467 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
468 
469 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
470 		doadump(TRUE);
471 
472 	/* Now that we're going to really halt the system... */
473 	EVENTHANDLER_INVOKE(shutdown_final, howto);
474 
475 	for(;;) ;	/* safety against shutdown_reset not working */
476 	/* NOTREACHED */
477 }
478 
479 /*
480  * The system call that results in changing the rootfs.
481  */
482 static int
483 kern_reroot(void)
484 {
485 	struct vnode *oldrootvnode, *vp;
486 	struct mount *mp, *devmp;
487 	int error;
488 
489 	if (curproc != initproc)
490 		return (EPERM);
491 
492 	/*
493 	 * Mark the filesystem containing currently-running executable
494 	 * (the temporary copy of init(8)) busy.
495 	 */
496 	vp = curproc->p_textvp;
497 	error = vn_lock(vp, LK_SHARED);
498 	if (error != 0)
499 		return (error);
500 	mp = vp->v_mount;
501 	error = vfs_busy(mp, MBF_NOWAIT);
502 	if (error != 0) {
503 		vfs_ref(mp);
504 		VOP_UNLOCK(vp, 0);
505 		error = vfs_busy(mp, 0);
506 		vn_lock(vp, LK_SHARED | LK_RETRY);
507 		vfs_rel(mp);
508 		if (error != 0) {
509 			VOP_UNLOCK(vp, 0);
510 			return (ENOENT);
511 		}
512 		if (vp->v_iflag & VI_DOOMED) {
513 			VOP_UNLOCK(vp, 0);
514 			vfs_unbusy(mp);
515 			return (ENOENT);
516 		}
517 	}
518 	VOP_UNLOCK(vp, 0);
519 
520 	/*
521 	 * Remove the filesystem containing currently-running executable
522 	 * from the mount list, to prevent it from being unmounted
523 	 * by vfs_unmountall(), and to avoid confusing vfs_mountroot().
524 	 *
525 	 * Also preserve /dev - forcibly unmounting it could cause driver
526 	 * reinitialization.
527 	 */
528 
529 	vfs_ref(rootdevmp);
530 	devmp = rootdevmp;
531 	rootdevmp = NULL;
532 
533 	mtx_lock(&mountlist_mtx);
534 	TAILQ_REMOVE(&mountlist, mp, mnt_list);
535 	TAILQ_REMOVE(&mountlist, devmp, mnt_list);
536 	mtx_unlock(&mountlist_mtx);
537 
538 	oldrootvnode = rootvnode;
539 
540 	/*
541 	 * Unmount everything except for the two filesystems preserved above.
542 	 */
543 	vfs_unmountall();
544 
545 	/*
546 	 * Add /dev back; vfs_mountroot() will move it into its new place.
547 	 */
548 	mtx_lock(&mountlist_mtx);
549 	TAILQ_INSERT_HEAD(&mountlist, devmp, mnt_list);
550 	mtx_unlock(&mountlist_mtx);
551 	rootdevmp = devmp;
552 	vfs_rel(rootdevmp);
553 
554 	/*
555 	 * Mount the new rootfs.
556 	 */
557 	vfs_mountroot();
558 
559 	/*
560 	 * Update all references to the old rootvnode.
561 	 */
562 	mountcheckdirs(oldrootvnode, rootvnode);
563 
564 	/*
565 	 * Add the temporary filesystem back and unbusy it.
566 	 */
567 	mtx_lock(&mountlist_mtx);
568 	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
569 	mtx_unlock(&mountlist_mtx);
570 	vfs_unbusy(mp);
571 
572 	return (0);
573 }
574 
575 /*
576  * If the shutdown was a clean halt, behave accordingly.
577  */
578 static void
579 shutdown_halt(void *junk, int howto)
580 {
581 
582 	if (howto & RB_HALT) {
583 		printf("\n");
584 		printf("The operating system has halted.\n");
585 		printf("Please press any key to reboot.\n\n");
586 		switch (cngetc()) {
587 		case -1:		/* No console, just die */
588 			cpu_halt();
589 			/* NOTREACHED */
590 		default:
591 			break;
592 		}
593 	}
594 }
595 
596 /*
597  * Check to see if the system paniced, pause and then reboot
598  * according to the specified delay.
599  */
600 static void
601 shutdown_panic(void *junk, int howto)
602 {
603 	int loop;
604 
605 	if (howto & RB_DUMP) {
606 		if (panic_reboot_wait_time != 0) {
607 			if (panic_reboot_wait_time != -1) {
608 				printf("Automatic reboot in %d seconds - "
609 				       "press a key on the console to abort\n",
610 					panic_reboot_wait_time);
611 				for (loop = panic_reboot_wait_time * 10;
612 				     loop > 0; --loop) {
613 					DELAY(1000 * 100); /* 1/10th second */
614 					/* Did user type a key? */
615 					if (cncheckc() != -1)
616 						break;
617 				}
618 				if (!loop)
619 					return;
620 			}
621 		} else { /* zero time specified - reboot NOW */
622 			return;
623 		}
624 		printf("--> Press a key on the console to reboot,\n");
625 		printf("--> or switch off the system now.\n");
626 		cngetc();
627 	}
628 }
629 
630 /*
631  * Everything done, now reset
632  */
633 static void
634 shutdown_reset(void *junk, int howto)
635 {
636 
637 	printf("Rebooting...\n");
638 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
639 
640 	/*
641 	 * Acquiring smp_ipi_mtx here has a double effect:
642 	 * - it disables interrupts avoiding CPU0 preemption
643 	 *   by fast handlers (thus deadlocking  against other CPUs)
644 	 * - it avoids deadlocks against smp_rendezvous() or, more
645 	 *   generally, threads busy-waiting, with this spinlock held,
646 	 *   and waiting for responses by threads on other CPUs
647 	 *   (ie. smp_tlb_shootdown()).
648 	 *
649 	 * For the !SMP case it just needs to handle the former problem.
650 	 */
651 #ifdef SMP
652 	mtx_lock_spin(&smp_ipi_mtx);
653 #else
654 	spinlock_enter();
655 #endif
656 
657 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
658 	cpu_reset();
659 	/* NOTREACHED */ /* assuming reset worked */
660 }
661 
662 #if defined(WITNESS) || defined(INVARIANT_SUPPORT)
663 static int kassert_warn_only = 0;
664 #ifdef KDB
665 static int kassert_do_kdb = 0;
666 #endif
667 #ifdef KTR
668 static int kassert_do_ktr = 0;
669 #endif
670 static int kassert_do_log = 1;
671 static int kassert_log_pps_limit = 4;
672 static int kassert_log_mute_at = 0;
673 static int kassert_log_panic_at = 0;
674 static int kassert_suppress_in_panic = 0;
675 static int kassert_warnings = 0;
676 
677 SYSCTL_NODE(_debug, OID_AUTO, kassert, CTLFLAG_RW, NULL, "kassert options");
678 
679 #ifdef KASSERT_PANIC_OPTIONAL
680 #define KASSERT_RWTUN	CTLFLAG_RWTUN
681 #else
682 #define KASSERT_RWTUN	CTLFLAG_RDTUN
683 #endif
684 
685 SYSCTL_INT(_debug_kassert, OID_AUTO, warn_only, KASSERT_RWTUN,
686     &kassert_warn_only, 0,
687     "KASSERT triggers a panic (0) or just a warning (1)");
688 
689 #ifdef KDB
690 SYSCTL_INT(_debug_kassert, OID_AUTO, do_kdb, KASSERT_RWTUN,
691     &kassert_do_kdb, 0, "KASSERT will enter the debugger");
692 #endif
693 
694 #ifdef KTR
695 SYSCTL_UINT(_debug_kassert, OID_AUTO, do_ktr, KASSERT_RWTUN,
696     &kassert_do_ktr, 0,
697     "KASSERT does a KTR, set this to the KTRMASK you want");
698 #endif
699 
700 SYSCTL_INT(_debug_kassert, OID_AUTO, do_log, KASSERT_RWTUN,
701     &kassert_do_log, 0,
702     "If warn_only is enabled, log (1) or do not log (0) assertion violations");
703 
704 SYSCTL_INT(_debug_kassert, OID_AUTO, warnings, KASSERT_RWTUN,
705     &kassert_warnings, 0, "number of KASSERTs that have been triggered");
706 
707 SYSCTL_INT(_debug_kassert, OID_AUTO, log_panic_at, KASSERT_RWTUN,
708     &kassert_log_panic_at, 0, "max number of KASSERTS before we will panic");
709 
710 SYSCTL_INT(_debug_kassert, OID_AUTO, log_pps_limit, KASSERT_RWTUN,
711     &kassert_log_pps_limit, 0, "limit number of log messages per second");
712 
713 SYSCTL_INT(_debug_kassert, OID_AUTO, log_mute_at, KASSERT_RWTUN,
714     &kassert_log_mute_at, 0, "max number of KASSERTS to log");
715 
716 SYSCTL_INT(_debug_kassert, OID_AUTO, suppress_in_panic, KASSERT_RWTUN,
717     &kassert_suppress_in_panic, 0,
718     "KASSERTs will be suppressed while handling a panic");
719 #undef KASSERT_RWTUN
720 
721 static int kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS);
722 
723 SYSCTL_PROC(_debug_kassert, OID_AUTO, kassert,
724     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0,
725     kassert_sysctl_kassert, "I", "set to trigger a test kassert");
726 
727 static int
728 kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS)
729 {
730 	int error, i;
731 
732 	error = sysctl_wire_old_buffer(req, sizeof(int));
733 	if (error == 0) {
734 		i = 0;
735 		error = sysctl_handle_int(oidp, &i, 0, req);
736 	}
737 	if (error != 0 || req->newptr == NULL)
738 		return (error);
739 	KASSERT(0, ("kassert_sysctl_kassert triggered kassert %d", i));
740 	return (0);
741 }
742 
743 #ifdef KASSERT_PANIC_OPTIONAL
744 /*
745  * Called by KASSERT, this decides if we will panic
746  * or if we will log via printf and/or ktr.
747  */
748 void
749 kassert_panic(const char *fmt, ...)
750 {
751 	static char buf[256];
752 	va_list ap;
753 
754 	va_start(ap, fmt);
755 	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
756 	va_end(ap);
757 
758 	/*
759 	 * If we are suppressing secondary panics, log the warning but do not
760 	 * re-enter panic/kdb.
761 	 */
762 	if (panicstr != NULL && kassert_suppress_in_panic) {
763 		if (kassert_do_log) {
764 			printf("KASSERT failed: %s\n", buf);
765 #ifdef KDB
766 			if (trace_all_panics && trace_on_panic)
767 				kdb_backtrace();
768 #endif
769 		}
770 		return;
771 	}
772 
773 	/*
774 	 * panic if we're not just warning, or if we've exceeded
775 	 * kassert_log_panic_at warnings.
776 	 */
777 	if (!kassert_warn_only ||
778 	    (kassert_log_panic_at > 0 &&
779 	     kassert_warnings >= kassert_log_panic_at)) {
780 		va_start(ap, fmt);
781 		vpanic(fmt, ap);
782 		/* NORETURN */
783 	}
784 #ifdef KTR
785 	if (kassert_do_ktr)
786 		CTR0(ktr_mask, buf);
787 #endif /* KTR */
788 	/*
789 	 * log if we've not yet met the mute limit.
790 	 */
791 	if (kassert_do_log &&
792 	    (kassert_log_mute_at == 0 ||
793 	     kassert_warnings < kassert_log_mute_at)) {
794 		static  struct timeval lasterr;
795 		static  int curerr;
796 
797 		if (ppsratecheck(&lasterr, &curerr, kassert_log_pps_limit)) {
798 			printf("KASSERT failed: %s\n", buf);
799 			kdb_backtrace();
800 		}
801 	}
802 #ifdef KDB
803 	if (kassert_do_kdb) {
804 		kdb_enter(KDB_WHY_KASSERT, buf);
805 	}
806 #endif
807 	atomic_add_int(&kassert_warnings, 1);
808 }
809 #endif /* KASSERT_PANIC_OPTIONAL */
810 #endif
811 
812 /*
813  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
814  * and then reboots.  If we are called twice, then we avoid trying to sync
815  * the disks as this often leads to recursive panics.
816  */
817 void
818 panic(const char *fmt, ...)
819 {
820 	va_list ap;
821 
822 	va_start(ap, fmt);
823 	vpanic(fmt, ap);
824 }
825 
826 void
827 vpanic(const char *fmt, va_list ap)
828 {
829 #ifdef SMP
830 	cpuset_t other_cpus;
831 #endif
832 	struct thread *td = curthread;
833 	int bootopt, newpanic;
834 	static char buf[256];
835 
836 	spinlock_enter();
837 
838 #ifdef SMP
839 	/*
840 	 * stop_cpus_hard(other_cpus) should prevent multiple CPUs from
841 	 * concurrently entering panic.  Only the winner will proceed
842 	 * further.
843 	 */
844 	if (panicstr == NULL && !kdb_active) {
845 		other_cpus = all_cpus;
846 		CPU_CLR(PCPU_GET(cpuid), &other_cpus);
847 		stop_cpus_hard(other_cpus);
848 	}
849 #endif
850 
851 	/*
852 	 * Ensure that the scheduler is stopped while panicking, even if panic
853 	 * has been entered from kdb.
854 	 */
855 	td->td_stopsched = 1;
856 
857 	bootopt = RB_AUTOBOOT;
858 	newpanic = 0;
859 	if (panicstr)
860 		bootopt |= RB_NOSYNC;
861 	else {
862 		bootopt |= RB_DUMP;
863 		panicstr = fmt;
864 		newpanic = 1;
865 	}
866 
867 	if (newpanic) {
868 		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
869 		panicstr = buf;
870 		cngrab();
871 		printf("panic: %s\n", buf);
872 	} else {
873 		printf("panic: ");
874 		vprintf(fmt, ap);
875 		printf("\n");
876 	}
877 #ifdef SMP
878 	printf("cpuid = %d\n", PCPU_GET(cpuid));
879 #endif
880 	printf("time = %jd\n", (intmax_t )time_second);
881 #ifdef KDB
882 	if ((newpanic || trace_all_panics) && trace_on_panic)
883 		kdb_backtrace();
884 	if (debugger_on_panic)
885 		kdb_enter(KDB_WHY_PANIC, "panic");
886 #endif
887 	/*thread_lock(td); */
888 	td->td_flags |= TDF_INPANIC;
889 	/* thread_unlock(td); */
890 	if (!sync_on_panic)
891 		bootopt |= RB_NOSYNC;
892 	if (poweroff_on_panic)
893 		bootopt |= RB_POWEROFF;
894 	if (powercycle_on_panic)
895 		bootopt |= RB_POWERCYCLE;
896 	kern_reboot(bootopt);
897 }
898 
899 /*
900  * Support for poweroff delay.
901  *
902  * Please note that setting this delay too short might power off your machine
903  * before the write cache on your hard disk has been flushed, leading to
904  * soft-updates inconsistencies.
905  */
906 #ifndef POWEROFF_DELAY
907 # define POWEROFF_DELAY 5000
908 #endif
909 static int poweroff_delay = POWEROFF_DELAY;
910 
911 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
912     &poweroff_delay, 0, "Delay before poweroff to write disk caches (msec)");
913 
914 static void
915 poweroff_wait(void *junk, int howto)
916 {
917 
918 	if ((howto & (RB_POWEROFF | RB_POWERCYCLE)) == 0 || poweroff_delay <= 0)
919 		return;
920 	DELAY(poweroff_delay * 1000);
921 }
922 
923 /*
924  * Some system processes (e.g. syncer) need to be stopped at appropriate
925  * points in their main loops prior to a system shutdown, so that they
926  * won't interfere with the shutdown process (e.g. by holding a disk buf
927  * to cause sync to fail).  For each of these system processes, register
928  * shutdown_kproc() as a handler for one of shutdown events.
929  */
930 static int kproc_shutdown_wait = 60;
931 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
932     &kproc_shutdown_wait, 0, "Max wait time (sec) to stop for each process");
933 
934 void
935 kproc_shutdown(void *arg, int howto)
936 {
937 	struct proc *p;
938 	int error;
939 
940 	if (panicstr)
941 		return;
942 
943 	p = (struct proc *)arg;
944 	printf("Waiting (max %d seconds) for system process `%s' to stop... ",
945 	    kproc_shutdown_wait, p->p_comm);
946 	error = kproc_suspend(p, kproc_shutdown_wait * hz);
947 
948 	if (error == EWOULDBLOCK)
949 		printf("timed out\n");
950 	else
951 		printf("done\n");
952 }
953 
954 void
955 kthread_shutdown(void *arg, int howto)
956 {
957 	struct thread *td;
958 	int error;
959 
960 	if (panicstr)
961 		return;
962 
963 	td = (struct thread *)arg;
964 	printf("Waiting (max %d seconds) for system thread `%s' to stop... ",
965 	    kproc_shutdown_wait, td->td_name);
966 	error = kthread_suspend(td, kproc_shutdown_wait * hz);
967 
968 	if (error == EWOULDBLOCK)
969 		printf("timed out\n");
970 	else
971 		printf("done\n");
972 }
973 
974 static int
975 dumpdevname_sysctl_handler(SYSCTL_HANDLER_ARGS)
976 {
977 	char buf[256];
978 	struct dumperinfo *di;
979 	struct sbuf sb;
980 	int error;
981 
982 	error = sysctl_wire_old_buffer(req, 0);
983 	if (error != 0)
984 		return (error);
985 
986 	sbuf_new_for_sysctl(&sb, buf, sizeof(buf), req);
987 
988 	mtx_lock(&dumpconf_list_lk);
989 	TAILQ_FOREACH(di, &dumper_configs, di_next) {
990 		if (di != TAILQ_FIRST(&dumper_configs))
991 			sbuf_putc(&sb, ',');
992 		sbuf_cat(&sb, di->di_devname);
993 	}
994 	mtx_unlock(&dumpconf_list_lk);
995 
996 	error = sbuf_finish(&sb);
997 	sbuf_delete(&sb);
998 	return (error);
999 }
1000 SYSCTL_PROC(_kern_shutdown, OID_AUTO, dumpdevname, CTLTYPE_STRING | CTLFLAG_RD,
1001     &dumper_configs, 0, dumpdevname_sysctl_handler, "A",
1002     "Device(s) for kernel dumps");
1003 
1004 static int	_dump_append(struct dumperinfo *di, void *virtual,
1005 		    vm_offset_t physical, size_t length);
1006 
1007 #ifdef EKCD
1008 static struct kerneldumpcrypto *
1009 kerneldumpcrypto_create(size_t blocksize, uint8_t encryption,
1010     const uint8_t *key, uint32_t encryptedkeysize, const uint8_t *encryptedkey)
1011 {
1012 	struct kerneldumpcrypto *kdc;
1013 	struct kerneldumpkey *kdk;
1014 	uint32_t dumpkeysize;
1015 
1016 	dumpkeysize = roundup2(sizeof(*kdk) + encryptedkeysize, blocksize);
1017 	kdc = malloc(sizeof(*kdc) + dumpkeysize, M_EKCD, M_WAITOK | M_ZERO);
1018 
1019 	arc4rand(kdc->kdc_iv, sizeof(kdc->kdc_iv), 0);
1020 
1021 	kdc->kdc_encryption = encryption;
1022 	switch (kdc->kdc_encryption) {
1023 	case KERNELDUMP_ENC_AES_256_CBC:
1024 		if (rijndael_makeKey(&kdc->kdc_ki, DIR_ENCRYPT, 256, key) <= 0)
1025 			goto failed;
1026 		break;
1027 	default:
1028 		goto failed;
1029 	}
1030 
1031 	kdc->kdc_dumpkeysize = dumpkeysize;
1032 	kdk = kdc->kdc_dumpkey;
1033 	kdk->kdk_encryption = kdc->kdc_encryption;
1034 	memcpy(kdk->kdk_iv, kdc->kdc_iv, sizeof(kdk->kdk_iv));
1035 	kdk->kdk_encryptedkeysize = htod32(encryptedkeysize);
1036 	memcpy(kdk->kdk_encryptedkey, encryptedkey, encryptedkeysize);
1037 
1038 	return (kdc);
1039 failed:
1040 	explicit_bzero(kdc, sizeof(*kdc) + dumpkeysize);
1041 	free(kdc, M_EKCD);
1042 	return (NULL);
1043 }
1044 
1045 static int
1046 kerneldumpcrypto_init(struct kerneldumpcrypto *kdc)
1047 {
1048 	uint8_t hash[SHA256_DIGEST_LENGTH];
1049 	SHA256_CTX ctx;
1050 	struct kerneldumpkey *kdk;
1051 	int error;
1052 
1053 	error = 0;
1054 
1055 	if (kdc == NULL)
1056 		return (0);
1057 
1058 	/*
1059 	 * When a user enters ddb it can write a crash dump multiple times.
1060 	 * Each time it should be encrypted using a different IV.
1061 	 */
1062 	SHA256_Init(&ctx);
1063 	SHA256_Update(&ctx, kdc->kdc_iv, sizeof(kdc->kdc_iv));
1064 	SHA256_Final(hash, &ctx);
1065 	bcopy(hash, kdc->kdc_iv, sizeof(kdc->kdc_iv));
1066 
1067 	switch (kdc->kdc_encryption) {
1068 	case KERNELDUMP_ENC_AES_256_CBC:
1069 		if (rijndael_cipherInit(&kdc->kdc_ci, MODE_CBC,
1070 		    kdc->kdc_iv) <= 0) {
1071 			error = EINVAL;
1072 			goto out;
1073 		}
1074 		break;
1075 	default:
1076 		error = EINVAL;
1077 		goto out;
1078 	}
1079 
1080 	kdk = kdc->kdc_dumpkey;
1081 	memcpy(kdk->kdk_iv, kdc->kdc_iv, sizeof(kdk->kdk_iv));
1082 out:
1083 	explicit_bzero(hash, sizeof(hash));
1084 	return (error);
1085 }
1086 
1087 static uint32_t
1088 kerneldumpcrypto_dumpkeysize(const struct kerneldumpcrypto *kdc)
1089 {
1090 
1091 	if (kdc == NULL)
1092 		return (0);
1093 	return (kdc->kdc_dumpkeysize);
1094 }
1095 #endif /* EKCD */
1096 
1097 static struct kerneldumpcomp *
1098 kerneldumpcomp_create(struct dumperinfo *di, uint8_t compression)
1099 {
1100 	struct kerneldumpcomp *kdcomp;
1101 	int format;
1102 
1103 	switch (compression) {
1104 	case KERNELDUMP_COMP_GZIP:
1105 		format = COMPRESS_GZIP;
1106 		break;
1107 	case KERNELDUMP_COMP_ZSTD:
1108 		format = COMPRESS_ZSTD;
1109 		break;
1110 	default:
1111 		return (NULL);
1112 	}
1113 
1114 	kdcomp = malloc(sizeof(*kdcomp), M_DUMPER, M_WAITOK | M_ZERO);
1115 	kdcomp->kdc_format = compression;
1116 	kdcomp->kdc_stream = compressor_init(kerneldumpcomp_write_cb,
1117 	    format, di->maxiosize, kerneldump_gzlevel, di);
1118 	if (kdcomp->kdc_stream == NULL) {
1119 		free(kdcomp, M_DUMPER);
1120 		return (NULL);
1121 	}
1122 	kdcomp->kdc_buf = malloc(di->maxiosize, M_DUMPER, M_WAITOK | M_NODUMP);
1123 	return (kdcomp);
1124 }
1125 
1126 static void
1127 kerneldumpcomp_destroy(struct dumperinfo *di)
1128 {
1129 	struct kerneldumpcomp *kdcomp;
1130 
1131 	kdcomp = di->kdcomp;
1132 	if (kdcomp == NULL)
1133 		return;
1134 	compressor_fini(kdcomp->kdc_stream);
1135 	explicit_bzero(kdcomp->kdc_buf, di->maxiosize);
1136 	free(kdcomp->kdc_buf, M_DUMPER);
1137 	free(kdcomp, M_DUMPER);
1138 }
1139 
1140 /*
1141  * Must not be present on global list.
1142  */
1143 static void
1144 free_single_dumper(struct dumperinfo *di)
1145 {
1146 
1147 	if (di == NULL)
1148 		return;
1149 
1150 	if (di->blockbuf != NULL) {
1151 		explicit_bzero(di->blockbuf, di->blocksize);
1152 		free(di->blockbuf, M_DUMPER);
1153 	}
1154 
1155 	kerneldumpcomp_destroy(di);
1156 
1157 #ifdef EKCD
1158 	if (di->kdcrypto != NULL) {
1159 		explicit_bzero(di->kdcrypto, sizeof(*di->kdcrypto) +
1160 		    di->kdcrypto->kdc_dumpkeysize);
1161 		free(di->kdcrypto, M_EKCD);
1162 	}
1163 #endif
1164 
1165 	explicit_bzero(di, sizeof(*di));
1166 	free(di, M_DUMPER);
1167 }
1168 
1169 /* Registration of dumpers */
1170 int
1171 dumper_insert(const struct dumperinfo *di_template, const char *devname,
1172     const struct diocskerneldump_arg *kda)
1173 {
1174 	struct dumperinfo *newdi, *listdi;
1175 	bool inserted;
1176 	uint8_t index;
1177 	int error;
1178 
1179 	index = kda->kda_index;
1180 	MPASS(index != KDA_REMOVE && index != KDA_REMOVE_DEV &&
1181 	    index != KDA_REMOVE_ALL);
1182 
1183 	error = priv_check(curthread, PRIV_SETDUMPER);
1184 	if (error != 0)
1185 		return (error);
1186 
1187 	newdi = malloc(sizeof(*newdi) + strlen(devname) + 1, M_DUMPER, M_WAITOK
1188 	    | M_ZERO);
1189 	memcpy(newdi, di_template, sizeof(*newdi));
1190 	newdi->blockbuf = NULL;
1191 	newdi->kdcrypto = NULL;
1192 	newdi->kdcomp = NULL;
1193 	strcpy(newdi->di_devname, devname);
1194 
1195 	if (kda->kda_encryption != KERNELDUMP_ENC_NONE) {
1196 #ifdef EKCD
1197 		newdi->kdcrypto = kerneldumpcrypto_create(di_template->blocksize,
1198 		    kda->kda_encryption, kda->kda_key,
1199 		    kda->kda_encryptedkeysize, kda->kda_encryptedkey);
1200 		if (newdi->kdcrypto == NULL) {
1201 			error = EINVAL;
1202 			goto cleanup;
1203 		}
1204 #else
1205 		error = EOPNOTSUPP;
1206 		goto cleanup;
1207 #endif
1208 	}
1209 	if (kda->kda_compression != KERNELDUMP_COMP_NONE) {
1210 		/*
1211 		 * We currently can't support simultaneous encryption and
1212 		 * compression because our only encryption mode is an unpadded
1213 		 * block cipher, go figure.  This is low hanging fruit to fix.
1214 		 */
1215 		if (kda->kda_encryption != KERNELDUMP_ENC_NONE) {
1216 			error = EOPNOTSUPP;
1217 			goto cleanup;
1218 		}
1219 		newdi->kdcomp = kerneldumpcomp_create(newdi,
1220 		    kda->kda_compression);
1221 		if (newdi->kdcomp == NULL) {
1222 			error = EINVAL;
1223 			goto cleanup;
1224 		}
1225 	}
1226 
1227 	newdi->blockbuf = malloc(newdi->blocksize, M_DUMPER, M_WAITOK | M_ZERO);
1228 
1229 	/* Add the new configuration to the queue */
1230 	mtx_lock(&dumpconf_list_lk);
1231 	inserted = false;
1232 	TAILQ_FOREACH(listdi, &dumper_configs, di_next) {
1233 		if (index == 0) {
1234 			TAILQ_INSERT_BEFORE(listdi, newdi, di_next);
1235 			inserted = true;
1236 			break;
1237 		}
1238 		index--;
1239 	}
1240 	if (!inserted)
1241 		TAILQ_INSERT_TAIL(&dumper_configs, newdi, di_next);
1242 	mtx_unlock(&dumpconf_list_lk);
1243 
1244 	return (0);
1245 
1246 cleanup:
1247 	free_single_dumper(newdi);
1248 	return (error);
1249 }
1250 
1251 static bool
1252 dumper_config_match(const struct dumperinfo *di, const char *devname,
1253     const struct diocskerneldump_arg *kda)
1254 {
1255 	if (kda->kda_index == KDA_REMOVE_ALL)
1256 		return (true);
1257 
1258 	if (strcmp(di->di_devname, devname) != 0)
1259 		return (false);
1260 
1261 	/*
1262 	 * Allow wildcard removal of configs matching a device on g_dev_orphan.
1263 	 */
1264 	if (kda->kda_index == KDA_REMOVE_DEV)
1265 		return (true);
1266 
1267 	if (di->kdcomp != NULL) {
1268 		if (di->kdcomp->kdc_format != kda->kda_compression)
1269 			return (false);
1270 	} else if (kda->kda_compression != KERNELDUMP_COMP_NONE)
1271 		return (false);
1272 #ifdef EKCD
1273 	if (di->kdcrypto != NULL) {
1274 		if (di->kdcrypto->kdc_encryption != kda->kda_encryption)
1275 			return (false);
1276 		/*
1277 		 * Do we care to verify keys match to delete?  It seems weird
1278 		 * to expect multiple fallback dump configurations on the same
1279 		 * device that only differ in crypto key.
1280 		 */
1281 	} else
1282 #endif
1283 		if (kda->kda_encryption != KERNELDUMP_ENC_NONE)
1284 			return (false);
1285 
1286 	return (true);
1287 }
1288 
1289 int
1290 dumper_remove(const char *devname, const struct diocskerneldump_arg *kda)
1291 {
1292 	struct dumperinfo *di, *sdi;
1293 	bool found;
1294 	int error;
1295 
1296 	error = priv_check(curthread, PRIV_SETDUMPER);
1297 	if (error != 0)
1298 		return (error);
1299 
1300 	/*
1301 	 * Try to find a matching configuration, and kill it.
1302 	 *
1303 	 * NULL 'kda' indicates remove any configuration matching 'devname',
1304 	 * which may remove multiple configurations in atypical configurations.
1305 	 */
1306 	found = false;
1307 	mtx_lock(&dumpconf_list_lk);
1308 	TAILQ_FOREACH_SAFE(di, &dumper_configs, di_next, sdi) {
1309 		if (dumper_config_match(di, devname, kda)) {
1310 			found = true;
1311 			TAILQ_REMOVE(&dumper_configs, di, di_next);
1312 			free_single_dumper(di);
1313 		}
1314 	}
1315 	mtx_unlock(&dumpconf_list_lk);
1316 
1317 	/* Only produce ENOENT if a more targeted match didn't match. */
1318 	if (!found && kda->kda_index == KDA_REMOVE)
1319 		return (ENOENT);
1320 	return (0);
1321 }
1322 
1323 static int
1324 dump_check_bounds(struct dumperinfo *di, off_t offset, size_t length)
1325 {
1326 
1327 	if (di->mediasize > 0 && length != 0 && (offset < di->mediaoffset ||
1328 	    offset - di->mediaoffset + length > di->mediasize)) {
1329 		if (di->kdcomp != NULL && offset >= di->mediaoffset) {
1330 			printf(
1331 		    "Compressed dump failed to fit in device boundaries.\n");
1332 			return (E2BIG);
1333 		}
1334 
1335 		printf("Attempt to write outside dump device boundaries.\n"
1336 	    "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
1337 		    (intmax_t)offset, (intmax_t)di->mediaoffset,
1338 		    (uintmax_t)length, (intmax_t)di->mediasize);
1339 		return (ENOSPC);
1340 	}
1341 	if (length % di->blocksize != 0) {
1342 		printf("Attempt to write partial block of length %ju.\n",
1343 		    (uintmax_t)length);
1344 		return (EINVAL);
1345 	}
1346 	if (offset % di->blocksize != 0) {
1347 		printf("Attempt to write at unaligned offset %jd.\n",
1348 		    (intmax_t)offset);
1349 		return (EINVAL);
1350 	}
1351 
1352 	return (0);
1353 }
1354 
1355 #ifdef EKCD
1356 static int
1357 dump_encrypt(struct kerneldumpcrypto *kdc, uint8_t *buf, size_t size)
1358 {
1359 
1360 	switch (kdc->kdc_encryption) {
1361 	case KERNELDUMP_ENC_AES_256_CBC:
1362 		if (rijndael_blockEncrypt(&kdc->kdc_ci, &kdc->kdc_ki, buf,
1363 		    8 * size, buf) <= 0) {
1364 			return (EIO);
1365 		}
1366 		if (rijndael_cipherInit(&kdc->kdc_ci, MODE_CBC,
1367 		    buf + size - 16 /* IV size for AES-256-CBC */) <= 0) {
1368 			return (EIO);
1369 		}
1370 		break;
1371 	default:
1372 		return (EINVAL);
1373 	}
1374 
1375 	return (0);
1376 }
1377 
1378 /* Encrypt data and call dumper. */
1379 static int
1380 dump_encrypted_write(struct dumperinfo *di, void *virtual,
1381     vm_offset_t physical, off_t offset, size_t length)
1382 {
1383 	static uint8_t buf[KERNELDUMP_BUFFER_SIZE];
1384 	struct kerneldumpcrypto *kdc;
1385 	int error;
1386 	size_t nbytes;
1387 
1388 	kdc = di->kdcrypto;
1389 
1390 	while (length > 0) {
1391 		nbytes = MIN(length, sizeof(buf));
1392 		bcopy(virtual, buf, nbytes);
1393 
1394 		if (dump_encrypt(kdc, buf, nbytes) != 0)
1395 			return (EIO);
1396 
1397 		error = dump_write(di, buf, physical, offset, nbytes);
1398 		if (error != 0)
1399 			return (error);
1400 
1401 		offset += nbytes;
1402 		virtual = (void *)((uint8_t *)virtual + nbytes);
1403 		length -= nbytes;
1404 	}
1405 
1406 	return (0);
1407 }
1408 #endif /* EKCD */
1409 
1410 static int
1411 kerneldumpcomp_write_cb(void *base, size_t length, off_t offset, void *arg)
1412 {
1413 	struct dumperinfo *di;
1414 	size_t resid, rlength;
1415 	int error;
1416 
1417 	di = arg;
1418 
1419 	if (length % di->blocksize != 0) {
1420 		/*
1421 		 * This must be the final write after flushing the compression
1422 		 * stream. Write as many full blocks as possible and stash the
1423 		 * residual data in the dumper's block buffer. It will be
1424 		 * padded and written in dump_finish().
1425 		 */
1426 		rlength = rounddown(length, di->blocksize);
1427 		if (rlength != 0) {
1428 			error = _dump_append(di, base, 0, rlength);
1429 			if (error != 0)
1430 				return (error);
1431 		}
1432 		resid = length - rlength;
1433 		memmove(di->blockbuf, (uint8_t *)base + rlength, resid);
1434 		di->kdcomp->kdc_resid = resid;
1435 		return (EAGAIN);
1436 	}
1437 	return (_dump_append(di, base, 0, length));
1438 }
1439 
1440 /*
1441  * Write kernel dump headers at the beginning and end of the dump extent.
1442  * Write the kernel dump encryption key after the leading header if we were
1443  * configured to do so.
1444  */
1445 static int
1446 dump_write_headers(struct dumperinfo *di, struct kerneldumpheader *kdh)
1447 {
1448 #ifdef EKCD
1449 	struct kerneldumpcrypto *kdc;
1450 #endif
1451 	void *buf, *key;
1452 	size_t hdrsz;
1453 	uint64_t extent;
1454 	uint32_t keysize;
1455 	int error;
1456 
1457 	hdrsz = sizeof(*kdh);
1458 	if (hdrsz > di->blocksize)
1459 		return (ENOMEM);
1460 
1461 #ifdef EKCD
1462 	kdc = di->kdcrypto;
1463 	key = kdc->kdc_dumpkey;
1464 	keysize = kerneldumpcrypto_dumpkeysize(kdc);
1465 #else
1466 	key = NULL;
1467 	keysize = 0;
1468 #endif
1469 
1470 	/*
1471 	 * If the dump device has special handling for headers, let it take care
1472 	 * of writing them out.
1473 	 */
1474 	if (di->dumper_hdr != NULL)
1475 		return (di->dumper_hdr(di, kdh, key, keysize));
1476 
1477 	if (hdrsz == di->blocksize)
1478 		buf = kdh;
1479 	else {
1480 		buf = di->blockbuf;
1481 		memset(buf, 0, di->blocksize);
1482 		memcpy(buf, kdh, hdrsz);
1483 	}
1484 
1485 	extent = dtoh64(kdh->dumpextent);
1486 #ifdef EKCD
1487 	if (kdc != NULL) {
1488 		error = dump_write(di, kdc->kdc_dumpkey, 0,
1489 		    di->mediaoffset + di->mediasize - di->blocksize - extent -
1490 		    keysize, keysize);
1491 		if (error != 0)
1492 			return (error);
1493 	}
1494 #endif
1495 
1496 	error = dump_write(di, buf, 0,
1497 	    di->mediaoffset + di->mediasize - 2 * di->blocksize - extent -
1498 	    keysize, di->blocksize);
1499 	if (error == 0)
1500 		error = dump_write(di, buf, 0, di->mediaoffset + di->mediasize -
1501 		    di->blocksize, di->blocksize);
1502 	return (error);
1503 }
1504 
1505 /*
1506  * Don't touch the first SIZEOF_METADATA bytes on the dump device.  This is to
1507  * protect us from metadata and metadata from us.
1508  */
1509 #define	SIZEOF_METADATA		(64 * 1024)
1510 
1511 /*
1512  * Do some preliminary setup for a kernel dump: initialize state for encryption,
1513  * if requested, and make sure that we have enough space on the dump device.
1514  *
1515  * We set things up so that the dump ends before the last sector of the dump
1516  * device, at which the trailing header is written.
1517  *
1518  *     +-----------+------+-----+----------------------------+------+
1519  *     |           | lhdr | key |    ... kernel dump ...     | thdr |
1520  *     +-----------+------+-----+----------------------------+------+
1521  *                   1 blk  opt <------- dump extent --------> 1 blk
1522  *
1523  * Dumps written using dump_append() start at the beginning of the extent.
1524  * Uncompressed dumps will use the entire extent, but compressed dumps typically
1525  * will not. The true length of the dump is recorded in the leading and trailing
1526  * headers once the dump has been completed.
1527  *
1528  * The dump device may provide a callback, in which case it will initialize
1529  * dumpoff and take care of laying out the headers.
1530  */
1531 int
1532 dump_start(struct dumperinfo *di, struct kerneldumpheader *kdh)
1533 {
1534 	uint64_t dumpextent, span;
1535 	uint32_t keysize;
1536 	int error;
1537 
1538 #ifdef EKCD
1539 	error = kerneldumpcrypto_init(di->kdcrypto);
1540 	if (error != 0)
1541 		return (error);
1542 	keysize = kerneldumpcrypto_dumpkeysize(di->kdcrypto);
1543 #else
1544 	error = 0;
1545 	keysize = 0;
1546 #endif
1547 
1548 	if (di->dumper_start != NULL) {
1549 		error = di->dumper_start(di);
1550 	} else {
1551 		dumpextent = dtoh64(kdh->dumpextent);
1552 		span = SIZEOF_METADATA + dumpextent + 2 * di->blocksize +
1553 		    keysize;
1554 		if (di->mediasize < span) {
1555 			if (di->kdcomp == NULL)
1556 				return (E2BIG);
1557 
1558 			/*
1559 			 * We don't yet know how much space the compressed dump
1560 			 * will occupy, so try to use the whole swap partition
1561 			 * (minus the first 64KB) in the hope that the
1562 			 * compressed dump will fit. If that doesn't turn out to
1563 			 * be enough, the bounds checking in dump_write()
1564 			 * will catch us and cause the dump to fail.
1565 			 */
1566 			dumpextent = di->mediasize - span + dumpextent;
1567 			kdh->dumpextent = htod64(dumpextent);
1568 		}
1569 
1570 		/*
1571 		 * The offset at which to begin writing the dump.
1572 		 */
1573 		di->dumpoff = di->mediaoffset + di->mediasize - di->blocksize -
1574 		    dumpextent;
1575 	}
1576 	di->origdumpoff = di->dumpoff;
1577 	return (error);
1578 }
1579 
1580 static int
1581 _dump_append(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1582     size_t length)
1583 {
1584 	int error;
1585 
1586 #ifdef EKCD
1587 	if (di->kdcrypto != NULL)
1588 		error = dump_encrypted_write(di, virtual, physical, di->dumpoff,
1589 		    length);
1590 	else
1591 #endif
1592 		error = dump_write(di, virtual, physical, di->dumpoff, length);
1593 	if (error == 0)
1594 		di->dumpoff += length;
1595 	return (error);
1596 }
1597 
1598 /*
1599  * Write to the dump device starting at dumpoff. When compression is enabled,
1600  * writes to the device will be performed using a callback that gets invoked
1601  * when the compression stream's output buffer is full.
1602  */
1603 int
1604 dump_append(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1605     size_t length)
1606 {
1607 	void *buf;
1608 
1609 	if (di->kdcomp != NULL) {
1610 		/* Bounce through a buffer to avoid CRC errors. */
1611 		if (length > di->maxiosize)
1612 			return (EINVAL);
1613 		buf = di->kdcomp->kdc_buf;
1614 		memmove(buf, virtual, length);
1615 		return (compressor_write(di->kdcomp->kdc_stream, buf, length));
1616 	}
1617 	return (_dump_append(di, virtual, physical, length));
1618 }
1619 
1620 /*
1621  * Write to the dump device at the specified offset.
1622  */
1623 int
1624 dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1625     off_t offset, size_t length)
1626 {
1627 	int error;
1628 
1629 	error = dump_check_bounds(di, offset, length);
1630 	if (error != 0)
1631 		return (error);
1632 	return (di->dumper(di->priv, virtual, physical, offset, length));
1633 }
1634 
1635 /*
1636  * Perform kernel dump finalization: flush the compression stream, if necessary,
1637  * write the leading and trailing kernel dump headers now that we know the true
1638  * length of the dump, and optionally write the encryption key following the
1639  * leading header.
1640  */
1641 int
1642 dump_finish(struct dumperinfo *di, struct kerneldumpheader *kdh)
1643 {
1644 	int error;
1645 
1646 	if (di->kdcomp != NULL) {
1647 		error = compressor_flush(di->kdcomp->kdc_stream);
1648 		if (error == EAGAIN) {
1649 			/* We have residual data in di->blockbuf. */
1650 			error = dump_write(di, di->blockbuf, 0, di->dumpoff,
1651 			    di->blocksize);
1652 			di->dumpoff += di->kdcomp->kdc_resid;
1653 			di->kdcomp->kdc_resid = 0;
1654 		}
1655 		if (error != 0)
1656 			return (error);
1657 
1658 		/*
1659 		 * We now know the size of the compressed dump, so update the
1660 		 * header accordingly and recompute parity.
1661 		 */
1662 		kdh->dumplength = htod64(di->dumpoff - di->origdumpoff);
1663 		kdh->parity = 0;
1664 		kdh->parity = kerneldump_parity(kdh);
1665 
1666 		compressor_reset(di->kdcomp->kdc_stream);
1667 	}
1668 
1669 	error = dump_write_headers(di, kdh);
1670 	if (error != 0)
1671 		return (error);
1672 
1673 	(void)dump_write(di, NULL, 0, 0, 0);
1674 	return (0);
1675 }
1676 
1677 void
1678 dump_init_header(const struct dumperinfo *di, struct kerneldumpheader *kdh,
1679     char *magic, uint32_t archver, uint64_t dumplen)
1680 {
1681 	size_t dstsize;
1682 
1683 	bzero(kdh, sizeof(*kdh));
1684 	strlcpy(kdh->magic, magic, sizeof(kdh->magic));
1685 	strlcpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
1686 	kdh->version = htod32(KERNELDUMPVERSION);
1687 	kdh->architectureversion = htod32(archver);
1688 	kdh->dumplength = htod64(dumplen);
1689 	kdh->dumpextent = kdh->dumplength;
1690 	kdh->dumptime = htod64(time_second);
1691 #ifdef EKCD
1692 	kdh->dumpkeysize = htod32(kerneldumpcrypto_dumpkeysize(di->kdcrypto));
1693 #else
1694 	kdh->dumpkeysize = 0;
1695 #endif
1696 	kdh->blocksize = htod32(di->blocksize);
1697 	strlcpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
1698 	dstsize = sizeof(kdh->versionstring);
1699 	if (strlcpy(kdh->versionstring, version, dstsize) >= dstsize)
1700 		kdh->versionstring[dstsize - 2] = '\n';
1701 	if (panicstr != NULL)
1702 		strlcpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
1703 	if (di->kdcomp != NULL)
1704 		kdh->compression = di->kdcomp->kdc_format;
1705 	kdh->parity = kerneldump_parity(kdh);
1706 }
1707 
1708 #ifdef DDB
1709 DB_SHOW_COMMAND(panic, db_show_panic)
1710 {
1711 
1712 	if (panicstr == NULL)
1713 		db_printf("panicstr not set\n");
1714 	else
1715 		db_printf("panic: %s\n", panicstr);
1716 }
1717 #endif
1718