xref: /freebsd/sys/kern/kern_shutdown.c (revision 4f52dfbb)
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_sched.h"
47 #include "opt_watchdog.h"
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/bio.h>
52 #include <sys/buf.h>
53 #include <sys/conf.h>
54 #include <sys/compressor.h>
55 #include <sys/cons.h>
56 #include <sys/eventhandler.h>
57 #include <sys/filedesc.h>
58 #include <sys/jail.h>
59 #include <sys/kdb.h>
60 #include <sys/kernel.h>
61 #include <sys/kerneldump.h>
62 #include <sys/kthread.h>
63 #include <sys/ktr.h>
64 #include <sys/malloc.h>
65 #include <sys/mbuf.h>
66 #include <sys/mount.h>
67 #include <sys/priv.h>
68 #include <sys/proc.h>
69 #include <sys/reboot.h>
70 #include <sys/resourcevar.h>
71 #include <sys/rwlock.h>
72 #include <sys/sched.h>
73 #include <sys/smp.h>
74 #include <sys/sysctl.h>
75 #include <sys/sysproto.h>
76 #include <sys/taskqueue.h>
77 #include <sys/vnode.h>
78 #include <sys/watchdog.h>
79 
80 #include <crypto/rijndael/rijndael-api-fst.h>
81 #include <crypto/sha2/sha256.h>
82 
83 #include <ddb/ddb.h>
84 
85 #include <machine/cpu.h>
86 #include <machine/dump.h>
87 #include <machine/pcb.h>
88 #include <machine/smp.h>
89 
90 #include <security/mac/mac_framework.h>
91 
92 #include <vm/vm.h>
93 #include <vm/vm_object.h>
94 #include <vm/vm_page.h>
95 #include <vm/vm_pager.h>
96 #include <vm/swap_pager.h>
97 
98 #include <sys/signalvar.h>
99 
100 static MALLOC_DEFINE(M_DUMPER, "dumper", "dumper block buffer");
101 
102 #ifndef PANIC_REBOOT_WAIT_TIME
103 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
104 #endif
105 static int panic_reboot_wait_time = PANIC_REBOOT_WAIT_TIME;
106 SYSCTL_INT(_kern, OID_AUTO, panic_reboot_wait_time, CTLFLAG_RWTUN,
107     &panic_reboot_wait_time, 0,
108     "Seconds to wait before rebooting after a panic");
109 
110 /*
111  * Note that stdarg.h and the ANSI style va_start macro is used for both
112  * ANSI and traditional C compilers.
113  */
114 #include <machine/stdarg.h>
115 
116 #ifdef KDB
117 #ifdef KDB_UNATTENDED
118 int debugger_on_panic = 0;
119 #else
120 int debugger_on_panic = 1;
121 #endif
122 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
123     CTLFLAG_RWTUN | CTLFLAG_SECURE,
124     &debugger_on_panic, 0, "Run debugger on kernel panic");
125 
126 #ifdef KDB_TRACE
127 static int trace_on_panic = 1;
128 static bool trace_all_panics = true;
129 #else
130 static int trace_on_panic = 0;
131 static bool trace_all_panics = false;
132 #endif
133 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
134     CTLFLAG_RWTUN | CTLFLAG_SECURE,
135     &trace_on_panic, 0, "Print stack trace on kernel panic");
136 SYSCTL_BOOL(_debug, OID_AUTO, trace_all_panics, CTLFLAG_RWTUN,
137     &trace_all_panics, 0, "Print stack traces on secondary kernel panics");
138 #endif /* KDB */
139 
140 static int sync_on_panic = 0;
141 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RWTUN,
142 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
143 
144 static bool poweroff_on_panic = 0;
145 SYSCTL_BOOL(_kern, OID_AUTO, poweroff_on_panic, CTLFLAG_RWTUN,
146 	&poweroff_on_panic, 0, "Do a power off instead of a reboot on a panic");
147 
148 static bool powercycle_on_panic = 0;
149 SYSCTL_BOOL(_kern, OID_AUTO, powercycle_on_panic, CTLFLAG_RWTUN,
150 	&powercycle_on_panic, 0, "Do a power cycle instead of a reboot on a panic");
151 
152 static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
153     "Shutdown environment");
154 
155 #ifndef DIAGNOSTIC
156 static int show_busybufs;
157 #else
158 static int show_busybufs = 1;
159 #endif
160 SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
161 	&show_busybufs, 0, "");
162 
163 int suspend_blocked = 0;
164 SYSCTL_INT(_kern, OID_AUTO, suspend_blocked, CTLFLAG_RW,
165 	&suspend_blocked, 0, "Block suspend due to a pending shutdown");
166 
167 #ifdef EKCD
168 FEATURE(ekcd, "Encrypted kernel crash dumps support");
169 
170 MALLOC_DEFINE(M_EKCD, "ekcd", "Encrypted kernel crash dumps data");
171 
172 struct kerneldumpcrypto {
173 	uint8_t			kdc_encryption;
174 	uint8_t			kdc_iv[KERNELDUMP_IV_MAX_SIZE];
175 	keyInstance		kdc_ki;
176 	cipherInstance		kdc_ci;
177 	uint32_t		kdc_dumpkeysize;
178 	struct kerneldumpkey	kdc_dumpkey[];
179 };
180 #endif
181 
182 struct kerneldumpcomp {
183 	uint8_t			kdc_format;
184 	struct compressor	*kdc_stream;
185 	uint8_t			*kdc_buf;
186 	size_t			kdc_resid;
187 };
188 
189 static struct kerneldumpcomp *kerneldumpcomp_create(struct dumperinfo *di,
190 		    uint8_t compression);
191 static void	kerneldumpcomp_destroy(struct dumperinfo *di);
192 static int	kerneldumpcomp_write_cb(void *base, size_t len, off_t off, void *arg);
193 
194 static int kerneldump_gzlevel = 6;
195 SYSCTL_INT(_kern, OID_AUTO, kerneldump_gzlevel, CTLFLAG_RWTUN,
196     &kerneldump_gzlevel, 0,
197     "Kernel crash dump compression level");
198 
199 /*
200  * Variable panicstr contains argument to first call to panic; used as flag
201  * to indicate that the kernel has already called panic.
202  */
203 const char *panicstr;
204 
205 int dumping;				/* system is dumping */
206 int rebooting;				/* system is rebooting */
207 static struct dumperinfo dumper;	/* our selected dumper */
208 
209 /* Context information for dump-debuggers. */
210 static struct pcb dumppcb;		/* Registers. */
211 lwpid_t dumptid;			/* Thread ID. */
212 
213 static struct cdevsw reroot_cdevsw = {
214      .d_version = D_VERSION,
215      .d_name    = "reroot",
216 };
217 
218 static void poweroff_wait(void *, int);
219 static void shutdown_halt(void *junk, int howto);
220 static void shutdown_panic(void *junk, int howto);
221 static void shutdown_reset(void *junk, int howto);
222 static int kern_reroot(void);
223 
224 /* register various local shutdown events */
225 static void
226 shutdown_conf(void *unused)
227 {
228 
229 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
230 	    SHUTDOWN_PRI_FIRST);
231 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
232 	    SHUTDOWN_PRI_LAST + 100);
233 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
234 	    SHUTDOWN_PRI_LAST + 100);
235 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
236 	    SHUTDOWN_PRI_LAST + 200);
237 }
238 
239 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
240 
241 /*
242  * The only reason this exists is to create the /dev/reroot/ directory,
243  * used by reroot code in init(8) as a mountpoint for tmpfs.
244  */
245 static void
246 reroot_conf(void *unused)
247 {
248 	int error;
249 	struct cdev *cdev;
250 
251 	error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &cdev,
252 	    &reroot_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "reroot/reroot");
253 	if (error != 0) {
254 		printf("%s: failed to create device node, error %d",
255 		    __func__, error);
256 	}
257 }
258 
259 SYSINIT(reroot_conf, SI_SUB_DEVFS, SI_ORDER_ANY, reroot_conf, NULL);
260 
261 /*
262  * The system call that results in a reboot.
263  */
264 /* ARGSUSED */
265 int
266 sys_reboot(struct thread *td, struct reboot_args *uap)
267 {
268 	int error;
269 
270 	error = 0;
271 #ifdef MAC
272 	error = mac_system_check_reboot(td->td_ucred, uap->opt);
273 #endif
274 	if (error == 0)
275 		error = priv_check(td, PRIV_REBOOT);
276 	if (error == 0) {
277 		if (uap->opt & RB_REROOT)
278 			error = kern_reroot();
279 		else
280 			kern_reboot(uap->opt);
281 	}
282 	return (error);
283 }
284 
285 static void
286 shutdown_nice_task_fn(void *arg, int pending __unused)
287 {
288 	int howto;
289 
290 	howto = (uintptr_t)arg;
291 	/* Send a signal to init(8) and have it shutdown the world. */
292 	PROC_LOCK(initproc);
293 	if (howto & RB_POWEROFF)
294 		kern_psignal(initproc, SIGUSR2);
295 	else if (howto & RB_POWERCYCLE)
296 		kern_psignal(initproc, SIGWINCH);
297 	else if (howto & RB_HALT)
298 		kern_psignal(initproc, SIGUSR1);
299 	else
300 		kern_psignal(initproc, SIGINT);
301 	PROC_UNLOCK(initproc);
302 }
303 
304 static struct task shutdown_nice_task = TASK_INITIALIZER(0,
305     &shutdown_nice_task_fn, NULL);
306 
307 /*
308  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
309  */
310 void
311 shutdown_nice(int howto)
312 {
313 
314 	if (initproc != NULL && !SCHEDULER_STOPPED()) {
315 		shutdown_nice_task.ta_context = (void *)(uintptr_t)howto;
316 		taskqueue_enqueue(taskqueue_fast, &shutdown_nice_task);
317 	} else {
318 		/*
319 		 * No init(8) running, or scheduler would not allow it
320 		 * to run, so simply reboot.
321 		 */
322 		kern_reboot(howto | RB_NOSYNC);
323 	}
324 }
325 
326 static void
327 print_uptime(void)
328 {
329 	int f;
330 	struct timespec ts;
331 
332 	getnanouptime(&ts);
333 	printf("Uptime: ");
334 	f = 0;
335 	if (ts.tv_sec >= 86400) {
336 		printf("%ldd", (long)ts.tv_sec / 86400);
337 		ts.tv_sec %= 86400;
338 		f = 1;
339 	}
340 	if (f || ts.tv_sec >= 3600) {
341 		printf("%ldh", (long)ts.tv_sec / 3600);
342 		ts.tv_sec %= 3600;
343 		f = 1;
344 	}
345 	if (f || ts.tv_sec >= 60) {
346 		printf("%ldm", (long)ts.tv_sec / 60);
347 		ts.tv_sec %= 60;
348 		f = 1;
349 	}
350 	printf("%lds\n", (long)ts.tv_sec);
351 }
352 
353 int
354 doadump(boolean_t textdump)
355 {
356 	boolean_t coredump;
357 	int error;
358 
359 	error = 0;
360 	if (dumping)
361 		return (EBUSY);
362 	if (dumper.dumper == NULL)
363 		return (ENXIO);
364 
365 	savectx(&dumppcb);
366 	dumptid = curthread->td_tid;
367 	dumping++;
368 
369 	coredump = TRUE;
370 #ifdef DDB
371 	if (textdump && textdump_pending) {
372 		coredump = FALSE;
373 		textdump_dumpsys(&dumper);
374 	}
375 #endif
376 	if (coredump)
377 		error = dumpsys(&dumper);
378 
379 	dumping--;
380 	return (error);
381 }
382 
383 /*
384  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
385  */
386 void
387 kern_reboot(int howto)
388 {
389 	static int once = 0;
390 
391 	/*
392 	 * Normal paths here don't hold Giant, but we can wind up here
393 	 * unexpectedly with it held.  Drop it now so we don't have to
394 	 * drop and pick it up elsewhere. The paths it is locking will
395 	 * never be returned to, and it is preferable to preclude
396 	 * deadlock than to lock against code that won't ever
397 	 * continue.
398 	 */
399 	while (mtx_owned(&Giant))
400 		mtx_unlock(&Giant);
401 
402 #if defined(SMP)
403 	/*
404 	 * Bind us to the first CPU so that all shutdown code runs there.  Some
405 	 * systems don't shutdown properly (i.e., ACPI power off) if we
406 	 * run on another processor.
407 	 */
408 	if (!SCHEDULER_STOPPED()) {
409 		thread_lock(curthread);
410 		sched_bind(curthread, CPU_FIRST());
411 		thread_unlock(curthread);
412 		KASSERT(PCPU_GET(cpuid) == CPU_FIRST(),
413 		    ("boot: not running on cpu 0"));
414 	}
415 #endif
416 	/* We're in the process of rebooting. */
417 	rebooting = 1;
418 
419 	/* We are out of the debugger now. */
420 	kdb_active = 0;
421 
422 	/*
423 	 * Do any callouts that should be done BEFORE syncing the filesystems.
424 	 */
425 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
426 
427 	/*
428 	 * Now sync filesystems
429 	 */
430 	if (!cold && (howto & RB_NOSYNC) == 0 && once == 0) {
431 		once = 1;
432 		bufshutdown(show_busybufs);
433 	}
434 
435 	print_uptime();
436 
437 	cngrab();
438 
439 	/*
440 	 * Ok, now do things that assume all filesystem activity has
441 	 * been completed.
442 	 */
443 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
444 
445 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
446 		doadump(TRUE);
447 
448 	/* Now that we're going to really halt the system... */
449 	EVENTHANDLER_INVOKE(shutdown_final, howto);
450 
451 	for(;;) ;	/* safety against shutdown_reset not working */
452 	/* NOTREACHED */
453 }
454 
455 /*
456  * The system call that results in changing the rootfs.
457  */
458 static int
459 kern_reroot(void)
460 {
461 	struct vnode *oldrootvnode, *vp;
462 	struct mount *mp, *devmp;
463 	int error;
464 
465 	if (curproc != initproc)
466 		return (EPERM);
467 
468 	/*
469 	 * Mark the filesystem containing currently-running executable
470 	 * (the temporary copy of init(8)) busy.
471 	 */
472 	vp = curproc->p_textvp;
473 	error = vn_lock(vp, LK_SHARED);
474 	if (error != 0)
475 		return (error);
476 	mp = vp->v_mount;
477 	error = vfs_busy(mp, MBF_NOWAIT);
478 	if (error != 0) {
479 		vfs_ref(mp);
480 		VOP_UNLOCK(vp, 0);
481 		error = vfs_busy(mp, 0);
482 		vn_lock(vp, LK_SHARED | LK_RETRY);
483 		vfs_rel(mp);
484 		if (error != 0) {
485 			VOP_UNLOCK(vp, 0);
486 			return (ENOENT);
487 		}
488 		if (vp->v_iflag & VI_DOOMED) {
489 			VOP_UNLOCK(vp, 0);
490 			vfs_unbusy(mp);
491 			return (ENOENT);
492 		}
493 	}
494 	VOP_UNLOCK(vp, 0);
495 
496 	/*
497 	 * Remove the filesystem containing currently-running executable
498 	 * from the mount list, to prevent it from being unmounted
499 	 * by vfs_unmountall(), and to avoid confusing vfs_mountroot().
500 	 *
501 	 * Also preserve /dev - forcibly unmounting it could cause driver
502 	 * reinitialization.
503 	 */
504 
505 	vfs_ref(rootdevmp);
506 	devmp = rootdevmp;
507 	rootdevmp = NULL;
508 
509 	mtx_lock(&mountlist_mtx);
510 	TAILQ_REMOVE(&mountlist, mp, mnt_list);
511 	TAILQ_REMOVE(&mountlist, devmp, mnt_list);
512 	mtx_unlock(&mountlist_mtx);
513 
514 	oldrootvnode = rootvnode;
515 
516 	/*
517 	 * Unmount everything except for the two filesystems preserved above.
518 	 */
519 	vfs_unmountall();
520 
521 	/*
522 	 * Add /dev back; vfs_mountroot() will move it into its new place.
523 	 */
524 	mtx_lock(&mountlist_mtx);
525 	TAILQ_INSERT_HEAD(&mountlist, devmp, mnt_list);
526 	mtx_unlock(&mountlist_mtx);
527 	rootdevmp = devmp;
528 	vfs_rel(rootdevmp);
529 
530 	/*
531 	 * Mount the new rootfs.
532 	 */
533 	vfs_mountroot();
534 
535 	/*
536 	 * Update all references to the old rootvnode.
537 	 */
538 	mountcheckdirs(oldrootvnode, rootvnode);
539 
540 	/*
541 	 * Add the temporary filesystem back and unbusy it.
542 	 */
543 	mtx_lock(&mountlist_mtx);
544 	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
545 	mtx_unlock(&mountlist_mtx);
546 	vfs_unbusy(mp);
547 
548 	return (0);
549 }
550 
551 /*
552  * If the shutdown was a clean halt, behave accordingly.
553  */
554 static void
555 shutdown_halt(void *junk, int howto)
556 {
557 
558 	if (howto & RB_HALT) {
559 		printf("\n");
560 		printf("The operating system has halted.\n");
561 		printf("Please press any key to reboot.\n\n");
562 		switch (cngetc()) {
563 		case -1:		/* No console, just die */
564 			cpu_halt();
565 			/* NOTREACHED */
566 		default:
567 			break;
568 		}
569 	}
570 }
571 
572 /*
573  * Check to see if the system paniced, pause and then reboot
574  * according to the specified delay.
575  */
576 static void
577 shutdown_panic(void *junk, int howto)
578 {
579 	int loop;
580 
581 	if (howto & RB_DUMP) {
582 		if (panic_reboot_wait_time != 0) {
583 			if (panic_reboot_wait_time != -1) {
584 				printf("Automatic reboot in %d seconds - "
585 				       "press a key on the console to abort\n",
586 					panic_reboot_wait_time);
587 				for (loop = panic_reboot_wait_time * 10;
588 				     loop > 0; --loop) {
589 					DELAY(1000 * 100); /* 1/10th second */
590 					/* Did user type a key? */
591 					if (cncheckc() != -1)
592 						break;
593 				}
594 				if (!loop)
595 					return;
596 			}
597 		} else { /* zero time specified - reboot NOW */
598 			return;
599 		}
600 		printf("--> Press a key on the console to reboot,\n");
601 		printf("--> or switch off the system now.\n");
602 		cngetc();
603 	}
604 }
605 
606 /*
607  * Everything done, now reset
608  */
609 static void
610 shutdown_reset(void *junk, int howto)
611 {
612 
613 	printf("Rebooting...\n");
614 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
615 
616 	/*
617 	 * Acquiring smp_ipi_mtx here has a double effect:
618 	 * - it disables interrupts avoiding CPU0 preemption
619 	 *   by fast handlers (thus deadlocking  against other CPUs)
620 	 * - it avoids deadlocks against smp_rendezvous() or, more
621 	 *   generally, threads busy-waiting, with this spinlock held,
622 	 *   and waiting for responses by threads on other CPUs
623 	 *   (ie. smp_tlb_shootdown()).
624 	 *
625 	 * For the !SMP case it just needs to handle the former problem.
626 	 */
627 #ifdef SMP
628 	mtx_lock_spin(&smp_ipi_mtx);
629 #else
630 	spinlock_enter();
631 #endif
632 
633 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
634 	cpu_reset();
635 	/* NOTREACHED */ /* assuming reset worked */
636 }
637 
638 #if defined(WITNESS) || defined(INVARIANT_SUPPORT)
639 static int kassert_warn_only = 0;
640 #ifdef KDB
641 static int kassert_do_kdb = 0;
642 #endif
643 #ifdef KTR
644 static int kassert_do_ktr = 0;
645 #endif
646 static int kassert_do_log = 1;
647 static int kassert_log_pps_limit = 4;
648 static int kassert_log_mute_at = 0;
649 static int kassert_log_panic_at = 0;
650 static int kassert_suppress_in_panic = 0;
651 static int kassert_warnings = 0;
652 
653 SYSCTL_NODE(_debug, OID_AUTO, kassert, CTLFLAG_RW, NULL, "kassert options");
654 
655 SYSCTL_INT(_debug_kassert, OID_AUTO, warn_only, CTLFLAG_RWTUN,
656     &kassert_warn_only, 0,
657     "KASSERT triggers a panic (1) or just a warning (0)");
658 
659 #ifdef KDB
660 SYSCTL_INT(_debug_kassert, OID_AUTO, do_kdb, CTLFLAG_RWTUN,
661     &kassert_do_kdb, 0, "KASSERT will enter the debugger");
662 #endif
663 
664 #ifdef KTR
665 SYSCTL_UINT(_debug_kassert, OID_AUTO, do_ktr, CTLFLAG_RWTUN,
666     &kassert_do_ktr, 0,
667     "KASSERT does a KTR, set this to the KTRMASK you want");
668 #endif
669 
670 SYSCTL_INT(_debug_kassert, OID_AUTO, do_log, CTLFLAG_RWTUN,
671     &kassert_do_log, 0,
672     "If warn_only is enabled, log (1) or do not log (0) assertion violations");
673 
674 SYSCTL_INT(_debug_kassert, OID_AUTO, warnings, CTLFLAG_RWTUN,
675     &kassert_warnings, 0, "number of KASSERTs that have been triggered");
676 
677 SYSCTL_INT(_debug_kassert, OID_AUTO, log_panic_at, CTLFLAG_RWTUN,
678     &kassert_log_panic_at, 0, "max number of KASSERTS before we will panic");
679 
680 SYSCTL_INT(_debug_kassert, OID_AUTO, log_pps_limit, CTLFLAG_RWTUN,
681     &kassert_log_pps_limit, 0, "limit number of log messages per second");
682 
683 SYSCTL_INT(_debug_kassert, OID_AUTO, log_mute_at, CTLFLAG_RWTUN,
684     &kassert_log_mute_at, 0, "max number of KASSERTS to log");
685 
686 SYSCTL_INT(_debug_kassert, OID_AUTO, suppress_in_panic, CTLFLAG_RWTUN,
687     &kassert_suppress_in_panic, 0,
688     "KASSERTs will be suppressed while handling a panic");
689 
690 static int kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS);
691 
692 SYSCTL_PROC(_debug_kassert, OID_AUTO, kassert,
693     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0,
694     kassert_sysctl_kassert, "I", "set to trigger a test kassert");
695 
696 static int
697 kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS)
698 {
699 	int error, i;
700 
701 	error = sysctl_wire_old_buffer(req, sizeof(int));
702 	if (error == 0) {
703 		i = 0;
704 		error = sysctl_handle_int(oidp, &i, 0, req);
705 	}
706 	if (error != 0 || req->newptr == NULL)
707 		return (error);
708 	KASSERT(0, ("kassert_sysctl_kassert triggered kassert %d", i));
709 	return (0);
710 }
711 
712 /*
713  * Called by KASSERT, this decides if we will panic
714  * or if we will log via printf and/or ktr.
715  */
716 void
717 kassert_panic(const char *fmt, ...)
718 {
719 	static char buf[256];
720 	va_list ap;
721 
722 	va_start(ap, fmt);
723 	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
724 	va_end(ap);
725 
726 	/*
727 	 * If we are suppressing secondary panics, log the warning but do not
728 	 * re-enter panic/kdb.
729 	 */
730 	if (panicstr != NULL && kassert_suppress_in_panic) {
731 		if (kassert_do_log) {
732 			printf("KASSERT failed: %s\n", buf);
733 #ifdef KDB
734 			if (trace_all_panics && trace_on_panic)
735 				kdb_backtrace();
736 #endif
737 		}
738 		return;
739 	}
740 
741 	/*
742 	 * panic if we're not just warning, or if we've exceeded
743 	 * kassert_log_panic_at warnings.
744 	 */
745 	if (!kassert_warn_only ||
746 	    (kassert_log_panic_at > 0 &&
747 	     kassert_warnings >= kassert_log_panic_at)) {
748 		va_start(ap, fmt);
749 		vpanic(fmt, ap);
750 		/* NORETURN */
751 	}
752 #ifdef KTR
753 	if (kassert_do_ktr)
754 		CTR0(ktr_mask, buf);
755 #endif /* KTR */
756 	/*
757 	 * log if we've not yet met the mute limit.
758 	 */
759 	if (kassert_do_log &&
760 	    (kassert_log_mute_at == 0 ||
761 	     kassert_warnings < kassert_log_mute_at)) {
762 		static  struct timeval lasterr;
763 		static  int curerr;
764 
765 		if (ppsratecheck(&lasterr, &curerr, kassert_log_pps_limit)) {
766 			printf("KASSERT failed: %s\n", buf);
767 			kdb_backtrace();
768 		}
769 	}
770 #ifdef KDB
771 	if (kassert_do_kdb) {
772 		kdb_enter(KDB_WHY_KASSERT, buf);
773 	}
774 #endif
775 	atomic_add_int(&kassert_warnings, 1);
776 }
777 #endif
778 
779 /*
780  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
781  * and then reboots.  If we are called twice, then we avoid trying to sync
782  * the disks as this often leads to recursive panics.
783  */
784 void
785 panic(const char *fmt, ...)
786 {
787 	va_list ap;
788 
789 	va_start(ap, fmt);
790 	vpanic(fmt, ap);
791 }
792 
793 void
794 vpanic(const char *fmt, va_list ap)
795 {
796 #ifdef SMP
797 	cpuset_t other_cpus;
798 #endif
799 	struct thread *td = curthread;
800 	int bootopt, newpanic;
801 	static char buf[256];
802 
803 	spinlock_enter();
804 
805 #ifdef SMP
806 	/*
807 	 * stop_cpus_hard(other_cpus) should prevent multiple CPUs from
808 	 * concurrently entering panic.  Only the winner will proceed
809 	 * further.
810 	 */
811 	if (panicstr == NULL && !kdb_active) {
812 		other_cpus = all_cpus;
813 		CPU_CLR(PCPU_GET(cpuid), &other_cpus);
814 		stop_cpus_hard(other_cpus);
815 	}
816 #endif
817 
818 	/*
819 	 * Ensure that the scheduler is stopped while panicking, even if panic
820 	 * has been entered from kdb.
821 	 */
822 	td->td_stopsched = 1;
823 
824 	bootopt = RB_AUTOBOOT;
825 	newpanic = 0;
826 	if (panicstr)
827 		bootopt |= RB_NOSYNC;
828 	else {
829 		bootopt |= RB_DUMP;
830 		panicstr = fmt;
831 		newpanic = 1;
832 	}
833 
834 	if (newpanic) {
835 		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
836 		panicstr = buf;
837 		cngrab();
838 		printf("panic: %s\n", buf);
839 	} else {
840 		printf("panic: ");
841 		vprintf(fmt, ap);
842 		printf("\n");
843 	}
844 #ifdef SMP
845 	printf("cpuid = %d\n", PCPU_GET(cpuid));
846 #endif
847 	printf("time = %jd\n", (intmax_t )time_second);
848 #ifdef KDB
849 	if ((newpanic || trace_all_panics) && trace_on_panic)
850 		kdb_backtrace();
851 	if (debugger_on_panic)
852 		kdb_enter(KDB_WHY_PANIC, "panic");
853 #endif
854 	/*thread_lock(td); */
855 	td->td_flags |= TDF_INPANIC;
856 	/* thread_unlock(td); */
857 	if (!sync_on_panic)
858 		bootopt |= RB_NOSYNC;
859 	if (poweroff_on_panic)
860 		bootopt |= RB_POWEROFF;
861 	if (powercycle_on_panic)
862 		bootopt |= RB_POWERCYCLE;
863 	kern_reboot(bootopt);
864 }
865 
866 /*
867  * Support for poweroff delay.
868  *
869  * Please note that setting this delay too short might power off your machine
870  * before the write cache on your hard disk has been flushed, leading to
871  * soft-updates inconsistencies.
872  */
873 #ifndef POWEROFF_DELAY
874 # define POWEROFF_DELAY 5000
875 #endif
876 static int poweroff_delay = POWEROFF_DELAY;
877 
878 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
879     &poweroff_delay, 0, "Delay before poweroff to write disk caches (msec)");
880 
881 static void
882 poweroff_wait(void *junk, int howto)
883 {
884 
885 	if ((howto & (RB_POWEROFF | RB_POWERCYCLE)) == 0 || poweroff_delay <= 0)
886 		return;
887 	DELAY(poweroff_delay * 1000);
888 }
889 
890 /*
891  * Some system processes (e.g. syncer) need to be stopped at appropriate
892  * points in their main loops prior to a system shutdown, so that they
893  * won't interfere with the shutdown process (e.g. by holding a disk buf
894  * to cause sync to fail).  For each of these system processes, register
895  * shutdown_kproc() as a handler for one of shutdown events.
896  */
897 static int kproc_shutdown_wait = 60;
898 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
899     &kproc_shutdown_wait, 0, "Max wait time (sec) to stop for each process");
900 
901 void
902 kproc_shutdown(void *arg, int howto)
903 {
904 	struct proc *p;
905 	int error;
906 
907 	if (panicstr)
908 		return;
909 
910 	p = (struct proc *)arg;
911 	printf("Waiting (max %d seconds) for system process `%s' to stop... ",
912 	    kproc_shutdown_wait, p->p_comm);
913 	error = kproc_suspend(p, kproc_shutdown_wait * hz);
914 
915 	if (error == EWOULDBLOCK)
916 		printf("timed out\n");
917 	else
918 		printf("done\n");
919 }
920 
921 void
922 kthread_shutdown(void *arg, int howto)
923 {
924 	struct thread *td;
925 	int error;
926 
927 	if (panicstr)
928 		return;
929 
930 	td = (struct thread *)arg;
931 	printf("Waiting (max %d seconds) for system thread `%s' to stop... ",
932 	    kproc_shutdown_wait, td->td_name);
933 	error = kthread_suspend(td, kproc_shutdown_wait * hz);
934 
935 	if (error == EWOULDBLOCK)
936 		printf("timed out\n");
937 	else
938 		printf("done\n");
939 }
940 
941 static char dumpdevname[sizeof(((struct cdev*)NULL)->si_name)];
942 SYSCTL_STRING(_kern_shutdown, OID_AUTO, dumpdevname, CTLFLAG_RD,
943     dumpdevname, 0, "Device for kernel dumps");
944 
945 static int	_dump_append(struct dumperinfo *di, void *virtual,
946 		    vm_offset_t physical, size_t length);
947 
948 #ifdef EKCD
949 static struct kerneldumpcrypto *
950 kerneldumpcrypto_create(size_t blocksize, uint8_t encryption,
951     const uint8_t *key, uint32_t encryptedkeysize, const uint8_t *encryptedkey)
952 {
953 	struct kerneldumpcrypto *kdc;
954 	struct kerneldumpkey *kdk;
955 	uint32_t dumpkeysize;
956 
957 	dumpkeysize = roundup2(sizeof(*kdk) + encryptedkeysize, blocksize);
958 	kdc = malloc(sizeof(*kdc) + dumpkeysize, M_EKCD, M_WAITOK | M_ZERO);
959 
960 	arc4rand(kdc->kdc_iv, sizeof(kdc->kdc_iv), 0);
961 
962 	kdc->kdc_encryption = encryption;
963 	switch (kdc->kdc_encryption) {
964 	case KERNELDUMP_ENC_AES_256_CBC:
965 		if (rijndael_makeKey(&kdc->kdc_ki, DIR_ENCRYPT, 256, key) <= 0)
966 			goto failed;
967 		break;
968 	default:
969 		goto failed;
970 	}
971 
972 	kdc->kdc_dumpkeysize = dumpkeysize;
973 	kdk = kdc->kdc_dumpkey;
974 	kdk->kdk_encryption = kdc->kdc_encryption;
975 	memcpy(kdk->kdk_iv, kdc->kdc_iv, sizeof(kdk->kdk_iv));
976 	kdk->kdk_encryptedkeysize = htod32(encryptedkeysize);
977 	memcpy(kdk->kdk_encryptedkey, encryptedkey, encryptedkeysize);
978 
979 	return (kdc);
980 failed:
981 	explicit_bzero(kdc, sizeof(*kdc) + dumpkeysize);
982 	free(kdc, M_EKCD);
983 	return (NULL);
984 }
985 
986 static int
987 kerneldumpcrypto_init(struct kerneldumpcrypto *kdc)
988 {
989 	uint8_t hash[SHA256_DIGEST_LENGTH];
990 	SHA256_CTX ctx;
991 	struct kerneldumpkey *kdk;
992 	int error;
993 
994 	error = 0;
995 
996 	if (kdc == NULL)
997 		return (0);
998 
999 	/*
1000 	 * When a user enters ddb it can write a crash dump multiple times.
1001 	 * Each time it should be encrypted using a different IV.
1002 	 */
1003 	SHA256_Init(&ctx);
1004 	SHA256_Update(&ctx, kdc->kdc_iv, sizeof(kdc->kdc_iv));
1005 	SHA256_Final(hash, &ctx);
1006 	bcopy(hash, kdc->kdc_iv, sizeof(kdc->kdc_iv));
1007 
1008 	switch (kdc->kdc_encryption) {
1009 	case KERNELDUMP_ENC_AES_256_CBC:
1010 		if (rijndael_cipherInit(&kdc->kdc_ci, MODE_CBC,
1011 		    kdc->kdc_iv) <= 0) {
1012 			error = EINVAL;
1013 			goto out;
1014 		}
1015 		break;
1016 	default:
1017 		error = EINVAL;
1018 		goto out;
1019 	}
1020 
1021 	kdk = kdc->kdc_dumpkey;
1022 	memcpy(kdk->kdk_iv, kdc->kdc_iv, sizeof(kdk->kdk_iv));
1023 out:
1024 	explicit_bzero(hash, sizeof(hash));
1025 	return (error);
1026 }
1027 
1028 static uint32_t
1029 kerneldumpcrypto_dumpkeysize(const struct kerneldumpcrypto *kdc)
1030 {
1031 
1032 	if (kdc == NULL)
1033 		return (0);
1034 	return (kdc->kdc_dumpkeysize);
1035 }
1036 #endif /* EKCD */
1037 
1038 static struct kerneldumpcomp *
1039 kerneldumpcomp_create(struct dumperinfo *di, uint8_t compression)
1040 {
1041 	struct kerneldumpcomp *kdcomp;
1042 	int format;
1043 
1044 	switch (compression) {
1045 	case KERNELDUMP_COMP_GZIP:
1046 		format = COMPRESS_GZIP;
1047 		break;
1048 	case KERNELDUMP_COMP_ZSTD:
1049 		format = COMPRESS_ZSTD;
1050 		break;
1051 	default:
1052 		return (NULL);
1053 	}
1054 
1055 	kdcomp = malloc(sizeof(*kdcomp), M_DUMPER, M_WAITOK | M_ZERO);
1056 	kdcomp->kdc_format = compression;
1057 	kdcomp->kdc_stream = compressor_init(kerneldumpcomp_write_cb,
1058 	    format, di->maxiosize, kerneldump_gzlevel, di);
1059 	if (kdcomp->kdc_stream == NULL) {
1060 		free(kdcomp, M_DUMPER);
1061 		return (NULL);
1062 	}
1063 	kdcomp->kdc_buf = malloc(di->maxiosize, M_DUMPER, M_WAITOK | M_NODUMP);
1064 	return (kdcomp);
1065 }
1066 
1067 static void
1068 kerneldumpcomp_destroy(struct dumperinfo *di)
1069 {
1070 	struct kerneldumpcomp *kdcomp;
1071 
1072 	kdcomp = di->kdcomp;
1073 	if (kdcomp == NULL)
1074 		return;
1075 	compressor_fini(kdcomp->kdc_stream);
1076 	explicit_bzero(kdcomp->kdc_buf, di->maxiosize);
1077 	free(kdcomp->kdc_buf, M_DUMPER);
1078 	free(kdcomp, M_DUMPER);
1079 }
1080 
1081 /* Registration of dumpers */
1082 int
1083 set_dumper(struct dumperinfo *di, const char *devname, struct thread *td,
1084     uint8_t compression, uint8_t encryption, const uint8_t *key,
1085     uint32_t encryptedkeysize, const uint8_t *encryptedkey)
1086 {
1087 	size_t wantcopy;
1088 	int error;
1089 
1090 	error = priv_check(td, PRIV_SETDUMPER);
1091 	if (error != 0)
1092 		return (error);
1093 
1094 	if (dumper.dumper != NULL)
1095 		return (EBUSY);
1096 	dumper = *di;
1097 	dumper.blockbuf = NULL;
1098 	dumper.kdcrypto = NULL;
1099 	dumper.kdcomp = NULL;
1100 
1101 	if (encryption != KERNELDUMP_ENC_NONE) {
1102 #ifdef EKCD
1103 		dumper.kdcrypto = kerneldumpcrypto_create(di->blocksize,
1104 		    encryption, key, encryptedkeysize, encryptedkey);
1105 		if (dumper.kdcrypto == NULL) {
1106 			error = EINVAL;
1107 			goto cleanup;
1108 		}
1109 #else
1110 		error = EOPNOTSUPP;
1111 		goto cleanup;
1112 #endif
1113 	}
1114 
1115 	wantcopy = strlcpy(dumpdevname, devname, sizeof(dumpdevname));
1116 	if (wantcopy >= sizeof(dumpdevname)) {
1117 		printf("set_dumper: device name truncated from '%s' -> '%s'\n",
1118 		    devname, dumpdevname);
1119 	}
1120 
1121 	if (compression != KERNELDUMP_COMP_NONE) {
1122 		/*
1123 		 * We currently can't support simultaneous encryption and
1124 		 * compression.
1125 		 */
1126 		if (encryption != KERNELDUMP_ENC_NONE) {
1127 			error = EOPNOTSUPP;
1128 			goto cleanup;
1129 		}
1130 		dumper.kdcomp = kerneldumpcomp_create(&dumper, compression);
1131 		if (dumper.kdcomp == NULL) {
1132 			error = EINVAL;
1133 			goto cleanup;
1134 		}
1135 	}
1136 
1137 	dumper.blockbuf = malloc(di->blocksize, M_DUMPER, M_WAITOK | M_ZERO);
1138 	return (0);
1139 
1140 cleanup:
1141 	(void)clear_dumper(td);
1142 	return (error);
1143 }
1144 
1145 int
1146 clear_dumper(struct thread *td)
1147 {
1148 	int error;
1149 
1150 	error = priv_check(td, PRIV_SETDUMPER);
1151 	if (error != 0)
1152 		return (error);
1153 
1154 #ifdef NETDUMP
1155 	netdump_mbuf_drain();
1156 #endif
1157 
1158 #ifdef EKCD
1159 	if (dumper.kdcrypto != NULL) {
1160 		explicit_bzero(dumper.kdcrypto, sizeof(*dumper.kdcrypto) +
1161 		    dumper.kdcrypto->kdc_dumpkeysize);
1162 		free(dumper.kdcrypto, M_EKCD);
1163 	}
1164 #endif
1165 
1166 	kerneldumpcomp_destroy(&dumper);
1167 
1168 	if (dumper.blockbuf != NULL) {
1169 		explicit_bzero(dumper.blockbuf, dumper.blocksize);
1170 		free(dumper.blockbuf, M_DUMPER);
1171 	}
1172 	explicit_bzero(&dumper, sizeof(dumper));
1173 	dumpdevname[0] = '\0';
1174 	return (0);
1175 }
1176 
1177 static int
1178 dump_check_bounds(struct dumperinfo *di, off_t offset, size_t length)
1179 {
1180 
1181 	if (di->mediasize > 0 && length != 0 && (offset < di->mediaoffset ||
1182 	    offset - di->mediaoffset + length > di->mediasize)) {
1183 		if (di->kdcomp != NULL && offset >= di->mediaoffset) {
1184 			printf(
1185 		    "Compressed dump failed to fit in device boundaries.\n");
1186 			return (E2BIG);
1187 		}
1188 
1189 		printf("Attempt to write outside dump device boundaries.\n"
1190 	    "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
1191 		    (intmax_t)offset, (intmax_t)di->mediaoffset,
1192 		    (uintmax_t)length, (intmax_t)di->mediasize);
1193 		return (ENOSPC);
1194 	}
1195 	if (length % di->blocksize != 0) {
1196 		printf("Attempt to write partial block of length %ju.\n",
1197 		    (uintmax_t)length);
1198 		return (EINVAL);
1199 	}
1200 	if (offset % di->blocksize != 0) {
1201 		printf("Attempt to write at unaligned offset %jd.\n",
1202 		    (intmax_t)offset);
1203 		return (EINVAL);
1204 	}
1205 
1206 	return (0);
1207 }
1208 
1209 #ifdef EKCD
1210 static int
1211 dump_encrypt(struct kerneldumpcrypto *kdc, uint8_t *buf, size_t size)
1212 {
1213 
1214 	switch (kdc->kdc_encryption) {
1215 	case KERNELDUMP_ENC_AES_256_CBC:
1216 		if (rijndael_blockEncrypt(&kdc->kdc_ci, &kdc->kdc_ki, buf,
1217 		    8 * size, buf) <= 0) {
1218 			return (EIO);
1219 		}
1220 		if (rijndael_cipherInit(&kdc->kdc_ci, MODE_CBC,
1221 		    buf + size - 16 /* IV size for AES-256-CBC */) <= 0) {
1222 			return (EIO);
1223 		}
1224 		break;
1225 	default:
1226 		return (EINVAL);
1227 	}
1228 
1229 	return (0);
1230 }
1231 
1232 /* Encrypt data and call dumper. */
1233 static int
1234 dump_encrypted_write(struct dumperinfo *di, void *virtual,
1235     vm_offset_t physical, off_t offset, size_t length)
1236 {
1237 	static uint8_t buf[KERNELDUMP_BUFFER_SIZE];
1238 	struct kerneldumpcrypto *kdc;
1239 	int error;
1240 	size_t nbytes;
1241 
1242 	kdc = di->kdcrypto;
1243 
1244 	while (length > 0) {
1245 		nbytes = MIN(length, sizeof(buf));
1246 		bcopy(virtual, buf, nbytes);
1247 
1248 		if (dump_encrypt(kdc, buf, nbytes) != 0)
1249 			return (EIO);
1250 
1251 		error = dump_write(di, buf, physical, offset, nbytes);
1252 		if (error != 0)
1253 			return (error);
1254 
1255 		offset += nbytes;
1256 		virtual = (void *)((uint8_t *)virtual + nbytes);
1257 		length -= nbytes;
1258 	}
1259 
1260 	return (0);
1261 }
1262 #endif /* EKCD */
1263 
1264 static int
1265 kerneldumpcomp_write_cb(void *base, size_t length, off_t offset, void *arg)
1266 {
1267 	struct dumperinfo *di;
1268 	size_t resid, rlength;
1269 	int error;
1270 
1271 	di = arg;
1272 
1273 	if (length % di->blocksize != 0) {
1274 		/*
1275 		 * This must be the final write after flushing the compression
1276 		 * stream. Write as many full blocks as possible and stash the
1277 		 * residual data in the dumper's block buffer. It will be
1278 		 * padded and written in dump_finish().
1279 		 */
1280 		rlength = rounddown(length, di->blocksize);
1281 		if (rlength != 0) {
1282 			error = _dump_append(di, base, 0, rlength);
1283 			if (error != 0)
1284 				return (error);
1285 		}
1286 		resid = length - rlength;
1287 		memmove(di->blockbuf, (uint8_t *)base + rlength, resid);
1288 		di->kdcomp->kdc_resid = resid;
1289 		return (EAGAIN);
1290 	}
1291 	return (_dump_append(di, base, 0, length));
1292 }
1293 
1294 /*
1295  * Write kernel dump headers at the beginning and end of the dump extent.
1296  * Write the kernel dump encryption key after the leading header if we were
1297  * configured to do so.
1298  */
1299 static int
1300 dump_write_headers(struct dumperinfo *di, struct kerneldumpheader *kdh)
1301 {
1302 #ifdef EKCD
1303 	struct kerneldumpcrypto *kdc;
1304 #endif
1305 	void *buf, *key;
1306 	size_t hdrsz;
1307 	uint64_t extent;
1308 	uint32_t keysize;
1309 	int error;
1310 
1311 	hdrsz = sizeof(*kdh);
1312 	if (hdrsz > di->blocksize)
1313 		return (ENOMEM);
1314 
1315 #ifdef EKCD
1316 	kdc = di->kdcrypto;
1317 	key = kdc->kdc_dumpkey;
1318 	keysize = kerneldumpcrypto_dumpkeysize(kdc);
1319 #else
1320 	key = NULL;
1321 	keysize = 0;
1322 #endif
1323 
1324 	/*
1325 	 * If the dump device has special handling for headers, let it take care
1326 	 * of writing them out.
1327 	 */
1328 	if (di->dumper_hdr != NULL)
1329 		return (di->dumper_hdr(di, kdh, key, keysize));
1330 
1331 	if (hdrsz == di->blocksize)
1332 		buf = kdh;
1333 	else {
1334 		buf = di->blockbuf;
1335 		memset(buf, 0, di->blocksize);
1336 		memcpy(buf, kdh, hdrsz);
1337 	}
1338 
1339 	extent = dtoh64(kdh->dumpextent);
1340 #ifdef EKCD
1341 	if (kdc != NULL) {
1342 		error = dump_write(di, kdc->kdc_dumpkey, 0,
1343 		    di->mediaoffset + di->mediasize - di->blocksize - extent -
1344 		    keysize, keysize);
1345 		if (error != 0)
1346 			return (error);
1347 	}
1348 #endif
1349 
1350 	error = dump_write(di, buf, 0,
1351 	    di->mediaoffset + di->mediasize - 2 * di->blocksize - extent -
1352 	    keysize, di->blocksize);
1353 	if (error == 0)
1354 		error = dump_write(di, buf, 0, di->mediaoffset + di->mediasize -
1355 		    di->blocksize, di->blocksize);
1356 	return (error);
1357 }
1358 
1359 /*
1360  * Don't touch the first SIZEOF_METADATA bytes on the dump device.  This is to
1361  * protect us from metadata and metadata from us.
1362  */
1363 #define	SIZEOF_METADATA		(64 * 1024)
1364 
1365 /*
1366  * Do some preliminary setup for a kernel dump: initialize state for encryption,
1367  * if requested, and make sure that we have enough space on the dump device.
1368  *
1369  * We set things up so that the dump ends before the last sector of the dump
1370  * device, at which the trailing header is written.
1371  *
1372  *     +-----------+------+-----+----------------------------+------+
1373  *     |           | lhdr | key |    ... kernel dump ...     | thdr |
1374  *     +-----------+------+-----+----------------------------+------+
1375  *                   1 blk  opt <------- dump extent --------> 1 blk
1376  *
1377  * Dumps written using dump_append() start at the beginning of the extent.
1378  * Uncompressed dumps will use the entire extent, but compressed dumps typically
1379  * will not. The true length of the dump is recorded in the leading and trailing
1380  * headers once the dump has been completed.
1381  *
1382  * The dump device may provide a callback, in which case it will initialize
1383  * dumpoff and take care of laying out the headers.
1384  */
1385 int
1386 dump_start(struct dumperinfo *di, struct kerneldumpheader *kdh)
1387 {
1388 	uint64_t dumpextent, span;
1389 	uint32_t keysize;
1390 	int error;
1391 
1392 #ifdef EKCD
1393 	error = kerneldumpcrypto_init(di->kdcrypto);
1394 	if (error != 0)
1395 		return (error);
1396 	keysize = kerneldumpcrypto_dumpkeysize(di->kdcrypto);
1397 #else
1398 	error = 0;
1399 	keysize = 0;
1400 #endif
1401 
1402 	if (di->dumper_start != NULL) {
1403 		error = di->dumper_start(di);
1404 	} else {
1405 		dumpextent = dtoh64(kdh->dumpextent);
1406 		span = SIZEOF_METADATA + dumpextent + 2 * di->blocksize +
1407 		    keysize;
1408 		if (di->mediasize < span) {
1409 			if (di->kdcomp == NULL)
1410 				return (E2BIG);
1411 
1412 			/*
1413 			 * We don't yet know how much space the compressed dump
1414 			 * will occupy, so try to use the whole swap partition
1415 			 * (minus the first 64KB) in the hope that the
1416 			 * compressed dump will fit. If that doesn't turn out to
1417 			 * be enough, the bounds checking in dump_write()
1418 			 * will catch us and cause the dump to fail.
1419 			 */
1420 			dumpextent = di->mediasize - span + dumpextent;
1421 			kdh->dumpextent = htod64(dumpextent);
1422 		}
1423 
1424 		/*
1425 		 * The offset at which to begin writing the dump.
1426 		 */
1427 		di->dumpoff = di->mediaoffset + di->mediasize - di->blocksize -
1428 		    dumpextent;
1429 	}
1430 	di->origdumpoff = di->dumpoff;
1431 	return (error);
1432 }
1433 
1434 static int
1435 _dump_append(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1436     size_t length)
1437 {
1438 	int error;
1439 
1440 #ifdef EKCD
1441 	if (di->kdcrypto != NULL)
1442 		error = dump_encrypted_write(di, virtual, physical, di->dumpoff,
1443 		    length);
1444 	else
1445 #endif
1446 		error = dump_write(di, virtual, physical, di->dumpoff, length);
1447 	if (error == 0)
1448 		di->dumpoff += length;
1449 	return (error);
1450 }
1451 
1452 /*
1453  * Write to the dump device starting at dumpoff. When compression is enabled,
1454  * writes to the device will be performed using a callback that gets invoked
1455  * when the compression stream's output buffer is full.
1456  */
1457 int
1458 dump_append(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1459     size_t length)
1460 {
1461 	void *buf;
1462 
1463 	if (di->kdcomp != NULL) {
1464 		/* Bounce through a buffer to avoid CRC errors. */
1465 		if (length > di->maxiosize)
1466 			return (EINVAL);
1467 		buf = di->kdcomp->kdc_buf;
1468 		memmove(buf, virtual, length);
1469 		return (compressor_write(di->kdcomp->kdc_stream, buf, length));
1470 	}
1471 	return (_dump_append(di, virtual, physical, length));
1472 }
1473 
1474 /*
1475  * Write to the dump device at the specified offset.
1476  */
1477 int
1478 dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1479     off_t offset, size_t length)
1480 {
1481 	int error;
1482 
1483 	error = dump_check_bounds(di, offset, length);
1484 	if (error != 0)
1485 		return (error);
1486 	return (di->dumper(di->priv, virtual, physical, offset, length));
1487 }
1488 
1489 /*
1490  * Perform kernel dump finalization: flush the compression stream, if necessary,
1491  * write the leading and trailing kernel dump headers now that we know the true
1492  * length of the dump, and optionally write the encryption key following the
1493  * leading header.
1494  */
1495 int
1496 dump_finish(struct dumperinfo *di, struct kerneldumpheader *kdh)
1497 {
1498 	uint64_t extent;
1499 	int error;
1500 
1501 	extent = dtoh64(kdh->dumpextent);
1502 
1503 	if (di->kdcomp != NULL) {
1504 		error = compressor_flush(di->kdcomp->kdc_stream);
1505 		if (error == EAGAIN) {
1506 			/* We have residual data in di->blockbuf. */
1507 			error = dump_write(di, di->blockbuf, 0, di->dumpoff,
1508 			    di->blocksize);
1509 			di->dumpoff += di->kdcomp->kdc_resid;
1510 			di->kdcomp->kdc_resid = 0;
1511 		}
1512 		if (error != 0)
1513 			return (error);
1514 
1515 		/*
1516 		 * We now know the size of the compressed dump, so update the
1517 		 * header accordingly and recompute parity.
1518 		 */
1519 		kdh->dumplength = htod64(di->dumpoff - di->origdumpoff);
1520 		kdh->parity = 0;
1521 		kdh->parity = kerneldump_parity(kdh);
1522 
1523 		compressor_reset(di->kdcomp->kdc_stream);
1524 	}
1525 
1526 	error = dump_write_headers(di, kdh);
1527 	if (error != 0)
1528 		return (error);
1529 
1530 	(void)dump_write(di, NULL, 0, 0, 0);
1531 	return (0);
1532 }
1533 
1534 void
1535 dump_init_header(const struct dumperinfo *di, struct kerneldumpheader *kdh,
1536     char *magic, uint32_t archver, uint64_t dumplen)
1537 {
1538 	size_t dstsize;
1539 
1540 	bzero(kdh, sizeof(*kdh));
1541 	strlcpy(kdh->magic, magic, sizeof(kdh->magic));
1542 	strlcpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
1543 	kdh->version = htod32(KERNELDUMPVERSION);
1544 	kdh->architectureversion = htod32(archver);
1545 	kdh->dumplength = htod64(dumplen);
1546 	kdh->dumpextent = kdh->dumplength;
1547 	kdh->dumptime = htod64(time_second);
1548 #ifdef EKCD
1549 	kdh->dumpkeysize = htod32(kerneldumpcrypto_dumpkeysize(di->kdcrypto));
1550 #else
1551 	kdh->dumpkeysize = 0;
1552 #endif
1553 	kdh->blocksize = htod32(di->blocksize);
1554 	strlcpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
1555 	dstsize = sizeof(kdh->versionstring);
1556 	if (strlcpy(kdh->versionstring, version, dstsize) >= dstsize)
1557 		kdh->versionstring[dstsize - 2] = '\n';
1558 	if (panicstr != NULL)
1559 		strlcpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
1560 	if (di->kdcomp != NULL)
1561 		kdh->compression = di->kdcomp->kdc_format;
1562 	kdh->parity = kerneldump_parity(kdh);
1563 }
1564 
1565 #ifdef DDB
1566 DB_SHOW_COMMAND(panic, db_show_panic)
1567 {
1568 
1569 	if (panicstr == NULL)
1570 		db_printf("panicstr not set\n");
1571 	else
1572 		db_printf("panic: %s\n", panicstr);
1573 }
1574 #endif
1575