xref: /freebsd/sys/kern/kern_shutdown.c (revision 38069501)
1 /*-
2  * Copyright (c) 1986, 1988, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)kern_shutdown.c	8.3 (Berkeley) 1/21/94
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "opt_ddb.h"
41 #include "opt_ekcd.h"
42 #include "opt_gzio.h"
43 #include "opt_kdb.h"
44 #include "opt_panic.h"
45 #include "opt_sched.h"
46 #include "opt_watchdog.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/bio.h>
51 #include <sys/buf.h>
52 #include <sys/conf.h>
53 #include <sys/cons.h>
54 #include <sys/eventhandler.h>
55 #include <sys/filedesc.h>
56 #include <sys/gzio.h>
57 #include <sys/jail.h>
58 #include <sys/kdb.h>
59 #include <sys/kernel.h>
60 #include <sys/kerneldump.h>
61 #include <sys/kthread.h>
62 #include <sys/ktr.h>
63 #include <sys/malloc.h>
64 #include <sys/mount.h>
65 #include <sys/priv.h>
66 #include <sys/proc.h>
67 #include <sys/reboot.h>
68 #include <sys/resourcevar.h>
69 #include <sys/rwlock.h>
70 #include <sys/sched.h>
71 #include <sys/smp.h>
72 #include <sys/sysctl.h>
73 #include <sys/sysproto.h>
74 #include <sys/vnode.h>
75 #include <sys/watchdog.h>
76 
77 #include <crypto/rijndael/rijndael-api-fst.h>
78 #include <crypto/sha2/sha256.h>
79 
80 #include <ddb/ddb.h>
81 
82 #include <machine/cpu.h>
83 #include <machine/dump.h>
84 #include <machine/pcb.h>
85 #include <machine/smp.h>
86 
87 #include <security/mac/mac_framework.h>
88 
89 #include <vm/vm.h>
90 #include <vm/vm_object.h>
91 #include <vm/vm_page.h>
92 #include <vm/vm_pager.h>
93 #include <vm/swap_pager.h>
94 
95 #include <sys/signalvar.h>
96 
97 static MALLOC_DEFINE(M_DUMPER, "dumper", "dumper block buffer");
98 
99 #ifndef PANIC_REBOOT_WAIT_TIME
100 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
101 #endif
102 static int panic_reboot_wait_time = PANIC_REBOOT_WAIT_TIME;
103 SYSCTL_INT(_kern, OID_AUTO, panic_reboot_wait_time, CTLFLAG_RWTUN,
104     &panic_reboot_wait_time, 0,
105     "Seconds to wait before rebooting after a panic");
106 
107 /*
108  * Note that stdarg.h and the ANSI style va_start macro is used for both
109  * ANSI and traditional C compilers.
110  */
111 #include <machine/stdarg.h>
112 
113 #ifdef KDB
114 #ifdef KDB_UNATTENDED
115 int debugger_on_panic = 0;
116 #else
117 int debugger_on_panic = 1;
118 #endif
119 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
120     CTLFLAG_RWTUN | CTLFLAG_SECURE,
121     &debugger_on_panic, 0, "Run debugger on kernel panic");
122 
123 #ifdef KDB_TRACE
124 static int trace_on_panic = 1;
125 #else
126 static int trace_on_panic = 0;
127 #endif
128 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic,
129     CTLFLAG_RWTUN | CTLFLAG_SECURE,
130     &trace_on_panic, 0, "Print stack trace on kernel panic");
131 #endif /* KDB */
132 
133 static int sync_on_panic = 0;
134 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RWTUN,
135 	&sync_on_panic, 0, "Do a sync before rebooting from a panic");
136 
137 static SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0,
138     "Shutdown environment");
139 
140 #ifndef DIAGNOSTIC
141 static int show_busybufs;
142 #else
143 static int show_busybufs = 1;
144 #endif
145 SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW,
146 	&show_busybufs, 0, "");
147 
148 int suspend_blocked = 0;
149 SYSCTL_INT(_kern, OID_AUTO, suspend_blocked, CTLFLAG_RW,
150 	&suspend_blocked, 0, "Block suspend due to a pending shutdown");
151 
152 #ifdef EKCD
153 FEATURE(ekcd, "Encrypted kernel crash dumps support");
154 
155 MALLOC_DEFINE(M_EKCD, "ekcd", "Encrypted kernel crash dumps data");
156 
157 struct kerneldumpcrypto {
158 	uint8_t			kdc_encryption;
159 	uint8_t			kdc_iv[KERNELDUMP_IV_MAX_SIZE];
160 	keyInstance		kdc_ki;
161 	cipherInstance		kdc_ci;
162 	uint32_t		kdc_dumpkeysize;
163 	struct kerneldumpkey	kdc_dumpkey[];
164 };
165 #endif
166 
167 #ifdef GZIO
168 struct kerneldumpgz {
169 	struct gzio_stream	*kdgz_stream;
170 	uint8_t			*kdgz_buf;
171 	size_t			kdgz_resid;
172 };
173 
174 static struct kerneldumpgz *kerneldumpgz_create(struct dumperinfo *di,
175 		    uint8_t compression);
176 static void	kerneldumpgz_destroy(struct dumperinfo *di);
177 static int	kerneldumpgz_write_cb(void *cb, size_t len, off_t off, void *arg);
178 
179 static int kerneldump_gzlevel = 6;
180 SYSCTL_INT(_kern, OID_AUTO, kerneldump_gzlevel, CTLFLAG_RWTUN,
181     &kerneldump_gzlevel, 0,
182     "Kernel crash dump gzip compression level");
183 #endif /* GZIO */
184 
185 /*
186  * Variable panicstr contains argument to first call to panic; used as flag
187  * to indicate that the kernel has already called panic.
188  */
189 const char *panicstr;
190 
191 int dumping;				/* system is dumping */
192 int rebooting;				/* system is rebooting */
193 static struct dumperinfo dumper;	/* our selected dumper */
194 
195 /* Context information for dump-debuggers. */
196 static struct pcb dumppcb;		/* Registers. */
197 lwpid_t dumptid;			/* Thread ID. */
198 
199 static struct cdevsw reroot_cdevsw = {
200      .d_version = D_VERSION,
201      .d_name    = "reroot",
202 };
203 
204 static void poweroff_wait(void *, int);
205 static void shutdown_halt(void *junk, int howto);
206 static void shutdown_panic(void *junk, int howto);
207 static void shutdown_reset(void *junk, int howto);
208 static int kern_reroot(void);
209 
210 /* register various local shutdown events */
211 static void
212 shutdown_conf(void *unused)
213 {
214 
215 	EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL,
216 	    SHUTDOWN_PRI_FIRST);
217 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL,
218 	    SHUTDOWN_PRI_LAST + 100);
219 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL,
220 	    SHUTDOWN_PRI_LAST + 100);
221 	EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL,
222 	    SHUTDOWN_PRI_LAST + 200);
223 }
224 
225 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL);
226 
227 /*
228  * The only reason this exists is to create the /dev/reroot/ directory,
229  * used by reroot code in init(8) as a mountpoint for tmpfs.
230  */
231 static void
232 reroot_conf(void *unused)
233 {
234 	int error;
235 	struct cdev *cdev;
236 
237 	error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &cdev,
238 	    &reroot_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "reroot/reroot");
239 	if (error != 0) {
240 		printf("%s: failed to create device node, error %d",
241 		    __func__, error);
242 	}
243 }
244 
245 SYSINIT(reroot_conf, SI_SUB_DEVFS, SI_ORDER_ANY, reroot_conf, NULL);
246 
247 /*
248  * The system call that results in a reboot.
249  */
250 /* ARGSUSED */
251 int
252 sys_reboot(struct thread *td, struct reboot_args *uap)
253 {
254 	int error;
255 
256 	error = 0;
257 #ifdef MAC
258 	error = mac_system_check_reboot(td->td_ucred, uap->opt);
259 #endif
260 	if (error == 0)
261 		error = priv_check(td, PRIV_REBOOT);
262 	if (error == 0) {
263 		if (uap->opt & RB_REROOT) {
264 			error = kern_reroot();
265 		} else {
266 			mtx_lock(&Giant);
267 			kern_reboot(uap->opt);
268 			mtx_unlock(&Giant);
269 		}
270 	}
271 	return (error);
272 }
273 
274 /*
275  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
276  */
277 void
278 shutdown_nice(int howto)
279 {
280 
281 	if (initproc != NULL) {
282 		/* Send a signal to init(8) and have it shutdown the world. */
283 		PROC_LOCK(initproc);
284 		if (howto & RB_POWEROFF)
285 			kern_psignal(initproc, SIGUSR2);
286 		else if (howto & RB_POWERCYCLE)
287 			kern_psignal(initproc, SIGWINCH);
288 		else if (howto & RB_HALT)
289 			kern_psignal(initproc, SIGUSR1);
290 		else
291 			kern_psignal(initproc, SIGINT);
292 		PROC_UNLOCK(initproc);
293 	} else {
294 		/* No init(8) running, so simply reboot. */
295 		kern_reboot(howto | RB_NOSYNC);
296 	}
297 }
298 
299 static void
300 print_uptime(void)
301 {
302 	int f;
303 	struct timespec ts;
304 
305 	getnanouptime(&ts);
306 	printf("Uptime: ");
307 	f = 0;
308 	if (ts.tv_sec >= 86400) {
309 		printf("%ldd", (long)ts.tv_sec / 86400);
310 		ts.tv_sec %= 86400;
311 		f = 1;
312 	}
313 	if (f || ts.tv_sec >= 3600) {
314 		printf("%ldh", (long)ts.tv_sec / 3600);
315 		ts.tv_sec %= 3600;
316 		f = 1;
317 	}
318 	if (f || ts.tv_sec >= 60) {
319 		printf("%ldm", (long)ts.tv_sec / 60);
320 		ts.tv_sec %= 60;
321 		f = 1;
322 	}
323 	printf("%lds\n", (long)ts.tv_sec);
324 }
325 
326 int
327 doadump(boolean_t textdump)
328 {
329 	boolean_t coredump;
330 	int error;
331 
332 	error = 0;
333 	if (dumping)
334 		return (EBUSY);
335 	if (dumper.dumper == NULL)
336 		return (ENXIO);
337 
338 	savectx(&dumppcb);
339 	dumptid = curthread->td_tid;
340 	dumping++;
341 
342 	coredump = TRUE;
343 #ifdef DDB
344 	if (textdump && textdump_pending) {
345 		coredump = FALSE;
346 		textdump_dumpsys(&dumper);
347 	}
348 #endif
349 	if (coredump)
350 		error = dumpsys(&dumper);
351 
352 	dumping--;
353 	return (error);
354 }
355 
356 /*
357  * Shutdown the system cleanly to prepare for reboot, halt, or power off.
358  */
359 void
360 kern_reboot(int howto)
361 {
362 	static int once = 0;
363 
364 #if defined(SMP)
365 	/*
366 	 * Bind us to CPU 0 so that all shutdown code runs there.  Some
367 	 * systems don't shutdown properly (i.e., ACPI power off) if we
368 	 * run on another processor.
369 	 */
370 	if (!SCHEDULER_STOPPED()) {
371 		thread_lock(curthread);
372 		sched_bind(curthread, 0);
373 		thread_unlock(curthread);
374 		KASSERT(PCPU_GET(cpuid) == 0, ("boot: not running on cpu 0"));
375 	}
376 #endif
377 	/* We're in the process of rebooting. */
378 	rebooting = 1;
379 
380 	/* We are out of the debugger now. */
381 	kdb_active = 0;
382 
383 	/*
384 	 * Do any callouts that should be done BEFORE syncing the filesystems.
385 	 */
386 	EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
387 
388 	/*
389 	 * Now sync filesystems
390 	 */
391 	if (!cold && (howto & RB_NOSYNC) == 0 && once == 0) {
392 		once = 1;
393 		bufshutdown(show_busybufs);
394 	}
395 
396 	print_uptime();
397 
398 	cngrab();
399 
400 	/*
401 	 * Ok, now do things that assume all filesystem activity has
402 	 * been completed.
403 	 */
404 	EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
405 
406 	if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold && !dumping)
407 		doadump(TRUE);
408 
409 	/* Now that we're going to really halt the system... */
410 	EVENTHANDLER_INVOKE(shutdown_final, howto);
411 
412 	for(;;) ;	/* safety against shutdown_reset not working */
413 	/* NOTREACHED */
414 }
415 
416 /*
417  * The system call that results in changing the rootfs.
418  */
419 static int
420 kern_reroot(void)
421 {
422 	struct vnode *oldrootvnode, *vp;
423 	struct mount *mp, *devmp;
424 	int error;
425 
426 	if (curproc != initproc)
427 		return (EPERM);
428 
429 	/*
430 	 * Mark the filesystem containing currently-running executable
431 	 * (the temporary copy of init(8)) busy.
432 	 */
433 	vp = curproc->p_textvp;
434 	error = vn_lock(vp, LK_SHARED);
435 	if (error != 0)
436 		return (error);
437 	mp = vp->v_mount;
438 	error = vfs_busy(mp, MBF_NOWAIT);
439 	if (error != 0) {
440 		vfs_ref(mp);
441 		VOP_UNLOCK(vp, 0);
442 		error = vfs_busy(mp, 0);
443 		vn_lock(vp, LK_SHARED | LK_RETRY);
444 		vfs_rel(mp);
445 		if (error != 0) {
446 			VOP_UNLOCK(vp, 0);
447 			return (ENOENT);
448 		}
449 		if (vp->v_iflag & VI_DOOMED) {
450 			VOP_UNLOCK(vp, 0);
451 			vfs_unbusy(mp);
452 			return (ENOENT);
453 		}
454 	}
455 	VOP_UNLOCK(vp, 0);
456 
457 	/*
458 	 * Remove the filesystem containing currently-running executable
459 	 * from the mount list, to prevent it from being unmounted
460 	 * by vfs_unmountall(), and to avoid confusing vfs_mountroot().
461 	 *
462 	 * Also preserve /dev - forcibly unmounting it could cause driver
463 	 * reinitialization.
464 	 */
465 
466 	vfs_ref(rootdevmp);
467 	devmp = rootdevmp;
468 	rootdevmp = NULL;
469 
470 	mtx_lock(&mountlist_mtx);
471 	TAILQ_REMOVE(&mountlist, mp, mnt_list);
472 	TAILQ_REMOVE(&mountlist, devmp, mnt_list);
473 	mtx_unlock(&mountlist_mtx);
474 
475 	oldrootvnode = rootvnode;
476 
477 	/*
478 	 * Unmount everything except for the two filesystems preserved above.
479 	 */
480 	vfs_unmountall();
481 
482 	/*
483 	 * Add /dev back; vfs_mountroot() will move it into its new place.
484 	 */
485 	mtx_lock(&mountlist_mtx);
486 	TAILQ_INSERT_HEAD(&mountlist, devmp, mnt_list);
487 	mtx_unlock(&mountlist_mtx);
488 	rootdevmp = devmp;
489 	vfs_rel(rootdevmp);
490 
491 	/*
492 	 * Mount the new rootfs.
493 	 */
494 	vfs_mountroot();
495 
496 	/*
497 	 * Update all references to the old rootvnode.
498 	 */
499 	mountcheckdirs(oldrootvnode, rootvnode);
500 
501 	/*
502 	 * Add the temporary filesystem back and unbusy it.
503 	 */
504 	mtx_lock(&mountlist_mtx);
505 	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
506 	mtx_unlock(&mountlist_mtx);
507 	vfs_unbusy(mp);
508 
509 	return (0);
510 }
511 
512 /*
513  * If the shutdown was a clean halt, behave accordingly.
514  */
515 static void
516 shutdown_halt(void *junk, int howto)
517 {
518 
519 	if (howto & RB_HALT) {
520 		printf("\n");
521 		printf("The operating system has halted.\n");
522 		printf("Please press any key to reboot.\n\n");
523 		switch (cngetc()) {
524 		case -1:		/* No console, just die */
525 			cpu_halt();
526 			/* NOTREACHED */
527 		default:
528 			howto &= ~RB_HALT;
529 			break;
530 		}
531 	}
532 }
533 
534 /*
535  * Check to see if the system paniced, pause and then reboot
536  * according to the specified delay.
537  */
538 static void
539 shutdown_panic(void *junk, int howto)
540 {
541 	int loop;
542 
543 	if (howto & RB_DUMP) {
544 		if (panic_reboot_wait_time != 0) {
545 			if (panic_reboot_wait_time != -1) {
546 				printf("Automatic reboot in %d seconds - "
547 				       "press a key on the console to abort\n",
548 					panic_reboot_wait_time);
549 				for (loop = panic_reboot_wait_time * 10;
550 				     loop > 0; --loop) {
551 					DELAY(1000 * 100); /* 1/10th second */
552 					/* Did user type a key? */
553 					if (cncheckc() != -1)
554 						break;
555 				}
556 				if (!loop)
557 					return;
558 			}
559 		} else { /* zero time specified - reboot NOW */
560 			return;
561 		}
562 		printf("--> Press a key on the console to reboot,\n");
563 		printf("--> or switch off the system now.\n");
564 		cngetc();
565 	}
566 }
567 
568 /*
569  * Everything done, now reset
570  */
571 static void
572 shutdown_reset(void *junk, int howto)
573 {
574 
575 	printf("Rebooting...\n");
576 	DELAY(1000000);	/* wait 1 sec for printf's to complete and be read */
577 
578 	/*
579 	 * Acquiring smp_ipi_mtx here has a double effect:
580 	 * - it disables interrupts avoiding CPU0 preemption
581 	 *   by fast handlers (thus deadlocking  against other CPUs)
582 	 * - it avoids deadlocks against smp_rendezvous() or, more
583 	 *   generally, threads busy-waiting, with this spinlock held,
584 	 *   and waiting for responses by threads on other CPUs
585 	 *   (ie. smp_tlb_shootdown()).
586 	 *
587 	 * For the !SMP case it just needs to handle the former problem.
588 	 */
589 #ifdef SMP
590 	mtx_lock_spin(&smp_ipi_mtx);
591 #else
592 	spinlock_enter();
593 #endif
594 
595 	/* cpu_boot(howto); */ /* doesn't do anything at the moment */
596 	cpu_reset();
597 	/* NOTREACHED */ /* assuming reset worked */
598 }
599 
600 #if defined(WITNESS) || defined(INVARIANT_SUPPORT)
601 static int kassert_warn_only = 0;
602 #ifdef KDB
603 static int kassert_do_kdb = 0;
604 #endif
605 #ifdef KTR
606 static int kassert_do_ktr = 0;
607 #endif
608 static int kassert_do_log = 1;
609 static int kassert_log_pps_limit = 4;
610 static int kassert_log_mute_at = 0;
611 static int kassert_log_panic_at = 0;
612 static int kassert_warnings = 0;
613 
614 SYSCTL_NODE(_debug, OID_AUTO, kassert, CTLFLAG_RW, NULL, "kassert options");
615 
616 SYSCTL_INT(_debug_kassert, OID_AUTO, warn_only, CTLFLAG_RWTUN,
617     &kassert_warn_only, 0,
618     "KASSERT triggers a panic (1) or just a warning (0)");
619 
620 #ifdef KDB
621 SYSCTL_INT(_debug_kassert, OID_AUTO, do_kdb, CTLFLAG_RWTUN,
622     &kassert_do_kdb, 0, "KASSERT will enter the debugger");
623 #endif
624 
625 #ifdef KTR
626 SYSCTL_UINT(_debug_kassert, OID_AUTO, do_ktr, CTLFLAG_RWTUN,
627     &kassert_do_ktr, 0,
628     "KASSERT does a KTR, set this to the KTRMASK you want");
629 #endif
630 
631 SYSCTL_INT(_debug_kassert, OID_AUTO, do_log, CTLFLAG_RWTUN,
632     &kassert_do_log, 0, "KASSERT triggers a panic (1) or just a warning (0)");
633 
634 SYSCTL_INT(_debug_kassert, OID_AUTO, warnings, CTLFLAG_RWTUN,
635     &kassert_warnings, 0, "number of KASSERTs that have been triggered");
636 
637 SYSCTL_INT(_debug_kassert, OID_AUTO, log_panic_at, CTLFLAG_RWTUN,
638     &kassert_log_panic_at, 0, "max number of KASSERTS before we will panic");
639 
640 SYSCTL_INT(_debug_kassert, OID_AUTO, log_pps_limit, CTLFLAG_RWTUN,
641     &kassert_log_pps_limit, 0, "limit number of log messages per second");
642 
643 SYSCTL_INT(_debug_kassert, OID_AUTO, log_mute_at, CTLFLAG_RWTUN,
644     &kassert_log_mute_at, 0, "max number of KASSERTS to log");
645 
646 static int kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS);
647 
648 SYSCTL_PROC(_debug_kassert, OID_AUTO, kassert,
649     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, NULL, 0,
650     kassert_sysctl_kassert, "I", "set to trigger a test kassert");
651 
652 static int
653 kassert_sysctl_kassert(SYSCTL_HANDLER_ARGS)
654 {
655 	int error, i;
656 
657 	error = sysctl_wire_old_buffer(req, sizeof(int));
658 	if (error == 0) {
659 		i = 0;
660 		error = sysctl_handle_int(oidp, &i, 0, req);
661 	}
662 	if (error != 0 || req->newptr == NULL)
663 		return (error);
664 	KASSERT(0, ("kassert_sysctl_kassert triggered kassert %d", i));
665 	return (0);
666 }
667 
668 /*
669  * Called by KASSERT, this decides if we will panic
670  * or if we will log via printf and/or ktr.
671  */
672 void
673 kassert_panic(const char *fmt, ...)
674 {
675 	static char buf[256];
676 	va_list ap;
677 
678 	va_start(ap, fmt);
679 	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
680 	va_end(ap);
681 
682 	/*
683 	 * panic if we're not just warning, or if we've exceeded
684 	 * kassert_log_panic_at warnings.
685 	 */
686 	if (!kassert_warn_only ||
687 	    (kassert_log_panic_at > 0 &&
688 	     kassert_warnings >= kassert_log_panic_at)) {
689 		va_start(ap, fmt);
690 		vpanic(fmt, ap);
691 		/* NORETURN */
692 	}
693 #ifdef KTR
694 	if (kassert_do_ktr)
695 		CTR0(ktr_mask, buf);
696 #endif /* KTR */
697 	/*
698 	 * log if we've not yet met the mute limit.
699 	 */
700 	if (kassert_do_log &&
701 	    (kassert_log_mute_at == 0 ||
702 	     kassert_warnings < kassert_log_mute_at)) {
703 		static  struct timeval lasterr;
704 		static  int curerr;
705 
706 		if (ppsratecheck(&lasterr, &curerr, kassert_log_pps_limit)) {
707 			printf("KASSERT failed: %s\n", buf);
708 			kdb_backtrace();
709 		}
710 	}
711 #ifdef KDB
712 	if (kassert_do_kdb) {
713 		kdb_enter(KDB_WHY_KASSERT, buf);
714 	}
715 #endif
716 	atomic_add_int(&kassert_warnings, 1);
717 }
718 #endif
719 
720 /*
721  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
722  * and then reboots.  If we are called twice, then we avoid trying to sync
723  * the disks as this often leads to recursive panics.
724  */
725 void
726 panic(const char *fmt, ...)
727 {
728 	va_list ap;
729 
730 	va_start(ap, fmt);
731 	vpanic(fmt, ap);
732 }
733 
734 void
735 vpanic(const char *fmt, va_list ap)
736 {
737 #ifdef SMP
738 	cpuset_t other_cpus;
739 #endif
740 	struct thread *td = curthread;
741 	int bootopt, newpanic;
742 	static char buf[256];
743 
744 	spinlock_enter();
745 
746 #ifdef SMP
747 	/*
748 	 * stop_cpus_hard(other_cpus) should prevent multiple CPUs from
749 	 * concurrently entering panic.  Only the winner will proceed
750 	 * further.
751 	 */
752 	if (panicstr == NULL && !kdb_active) {
753 		other_cpus = all_cpus;
754 		CPU_CLR(PCPU_GET(cpuid), &other_cpus);
755 		stop_cpus_hard(other_cpus);
756 	}
757 #endif
758 
759 	/*
760 	 * Ensure that the scheduler is stopped while panicking, even if panic
761 	 * has been entered from kdb.
762 	 */
763 	td->td_stopsched = 1;
764 
765 	bootopt = RB_AUTOBOOT;
766 	newpanic = 0;
767 	if (panicstr)
768 		bootopt |= RB_NOSYNC;
769 	else {
770 		bootopt |= RB_DUMP;
771 		panicstr = fmt;
772 		newpanic = 1;
773 	}
774 
775 	if (newpanic) {
776 		(void)vsnprintf(buf, sizeof(buf), fmt, ap);
777 		panicstr = buf;
778 		cngrab();
779 		printf("panic: %s\n", buf);
780 	} else {
781 		printf("panic: ");
782 		vprintf(fmt, ap);
783 		printf("\n");
784 	}
785 #ifdef SMP
786 	printf("cpuid = %d\n", PCPU_GET(cpuid));
787 #endif
788 	printf("time = %jd\n", (intmax_t )time_second);
789 #ifdef KDB
790 	if (newpanic && trace_on_panic)
791 		kdb_backtrace();
792 	if (debugger_on_panic)
793 		kdb_enter(KDB_WHY_PANIC, "panic");
794 #endif
795 	/*thread_lock(td); */
796 	td->td_flags |= TDF_INPANIC;
797 	/* thread_unlock(td); */
798 	if (!sync_on_panic)
799 		bootopt |= RB_NOSYNC;
800 	kern_reboot(bootopt);
801 }
802 
803 /*
804  * Support for poweroff delay.
805  *
806  * Please note that setting this delay too short might power off your machine
807  * before the write cache on your hard disk has been flushed, leading to
808  * soft-updates inconsistencies.
809  */
810 #ifndef POWEROFF_DELAY
811 # define POWEROFF_DELAY 5000
812 #endif
813 static int poweroff_delay = POWEROFF_DELAY;
814 
815 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
816     &poweroff_delay, 0, "Delay before poweroff to write disk caches (msec)");
817 
818 static void
819 poweroff_wait(void *junk, int howto)
820 {
821 
822 	if ((howto & (RB_POWEROFF | RB_POWERCYCLE)) == 0 || poweroff_delay <= 0)
823 		return;
824 	DELAY(poweroff_delay * 1000);
825 }
826 
827 /*
828  * Some system processes (e.g. syncer) need to be stopped at appropriate
829  * points in their main loops prior to a system shutdown, so that they
830  * won't interfere with the shutdown process (e.g. by holding a disk buf
831  * to cause sync to fail).  For each of these system processes, register
832  * shutdown_kproc() as a handler for one of shutdown events.
833  */
834 static int kproc_shutdown_wait = 60;
835 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
836     &kproc_shutdown_wait, 0, "Max wait time (sec) to stop for each process");
837 
838 void
839 kproc_shutdown(void *arg, int howto)
840 {
841 	struct proc *p;
842 	int error;
843 
844 	if (panicstr)
845 		return;
846 
847 	p = (struct proc *)arg;
848 	printf("Waiting (max %d seconds) for system process `%s' to stop... ",
849 	    kproc_shutdown_wait, p->p_comm);
850 	error = kproc_suspend(p, kproc_shutdown_wait * hz);
851 
852 	if (error == EWOULDBLOCK)
853 		printf("timed out\n");
854 	else
855 		printf("done\n");
856 }
857 
858 void
859 kthread_shutdown(void *arg, int howto)
860 {
861 	struct thread *td;
862 	int error;
863 
864 	if (panicstr)
865 		return;
866 
867 	td = (struct thread *)arg;
868 	printf("Waiting (max %d seconds) for system thread `%s' to stop... ",
869 	    kproc_shutdown_wait, td->td_name);
870 	error = kthread_suspend(td, kproc_shutdown_wait * hz);
871 
872 	if (error == EWOULDBLOCK)
873 		printf("timed out\n");
874 	else
875 		printf("done\n");
876 }
877 
878 static char dumpdevname[sizeof(((struct cdev*)NULL)->si_name)];
879 SYSCTL_STRING(_kern_shutdown, OID_AUTO, dumpdevname, CTLFLAG_RD,
880     dumpdevname, 0, "Device for kernel dumps");
881 
882 static int	_dump_append(struct dumperinfo *di, void *virtual,
883 		    vm_offset_t physical, size_t length);
884 
885 #ifdef EKCD
886 static struct kerneldumpcrypto *
887 kerneldumpcrypto_create(size_t blocksize, uint8_t encryption,
888     const uint8_t *key, uint32_t encryptedkeysize, const uint8_t *encryptedkey)
889 {
890 	struct kerneldumpcrypto *kdc;
891 	struct kerneldumpkey *kdk;
892 	uint32_t dumpkeysize;
893 
894 	dumpkeysize = roundup2(sizeof(*kdk) + encryptedkeysize, blocksize);
895 	kdc = malloc(sizeof(*kdc) + dumpkeysize, M_EKCD, M_WAITOK | M_ZERO);
896 
897 	arc4rand(kdc->kdc_iv, sizeof(kdc->kdc_iv), 0);
898 
899 	kdc->kdc_encryption = encryption;
900 	switch (kdc->kdc_encryption) {
901 	case KERNELDUMP_ENC_AES_256_CBC:
902 		if (rijndael_makeKey(&kdc->kdc_ki, DIR_ENCRYPT, 256, key) <= 0)
903 			goto failed;
904 		break;
905 	default:
906 		goto failed;
907 	}
908 
909 	kdc->kdc_dumpkeysize = dumpkeysize;
910 	kdk = kdc->kdc_dumpkey;
911 	kdk->kdk_encryption = kdc->kdc_encryption;
912 	memcpy(kdk->kdk_iv, kdc->kdc_iv, sizeof(kdk->kdk_iv));
913 	kdk->kdk_encryptedkeysize = htod32(encryptedkeysize);
914 	memcpy(kdk->kdk_encryptedkey, encryptedkey, encryptedkeysize);
915 
916 	return (kdc);
917 failed:
918 	explicit_bzero(kdc, sizeof(*kdc) + dumpkeysize);
919 	free(kdc, M_EKCD);
920 	return (NULL);
921 }
922 
923 static int
924 kerneldumpcrypto_init(struct kerneldumpcrypto *kdc)
925 {
926 	uint8_t hash[SHA256_DIGEST_LENGTH];
927 	SHA256_CTX ctx;
928 	struct kerneldumpkey *kdk;
929 	int error;
930 
931 	error = 0;
932 
933 	if (kdc == NULL)
934 		return (0);
935 
936 	/*
937 	 * When a user enters ddb it can write a crash dump multiple times.
938 	 * Each time it should be encrypted using a different IV.
939 	 */
940 	SHA256_Init(&ctx);
941 	SHA256_Update(&ctx, kdc->kdc_iv, sizeof(kdc->kdc_iv));
942 	SHA256_Final(hash, &ctx);
943 	bcopy(hash, kdc->kdc_iv, sizeof(kdc->kdc_iv));
944 
945 	switch (kdc->kdc_encryption) {
946 	case KERNELDUMP_ENC_AES_256_CBC:
947 		if (rijndael_cipherInit(&kdc->kdc_ci, MODE_CBC,
948 		    kdc->kdc_iv) <= 0) {
949 			error = EINVAL;
950 			goto out;
951 		}
952 		break;
953 	default:
954 		error = EINVAL;
955 		goto out;
956 	}
957 
958 	kdk = kdc->kdc_dumpkey;
959 	memcpy(kdk->kdk_iv, kdc->kdc_iv, sizeof(kdk->kdk_iv));
960 out:
961 	explicit_bzero(hash, sizeof(hash));
962 	return (error);
963 }
964 
965 static uint32_t
966 kerneldumpcrypto_dumpkeysize(const struct kerneldumpcrypto *kdc)
967 {
968 
969 	if (kdc == NULL)
970 		return (0);
971 	return (kdc->kdc_dumpkeysize);
972 }
973 #endif /* EKCD */
974 
975 #ifdef GZIO
976 static struct kerneldumpgz *
977 kerneldumpgz_create(struct dumperinfo *di, uint8_t compression)
978 {
979 	struct kerneldumpgz *kdgz;
980 
981 	if (compression != KERNELDUMP_COMP_GZIP)
982 		return (NULL);
983 	kdgz = malloc(sizeof(*kdgz), M_DUMPER, M_WAITOK | M_ZERO);
984 	kdgz->kdgz_stream = gzio_init(kerneldumpgz_write_cb, GZIO_DEFLATE,
985 	    di->maxiosize, kerneldump_gzlevel, di);
986 	if (kdgz->kdgz_stream == NULL) {
987 		free(kdgz, M_DUMPER);
988 		return (NULL);
989 	}
990 	kdgz->kdgz_buf = malloc(di->maxiosize, M_DUMPER, M_WAITOK | M_NODUMP);
991 	return (kdgz);
992 }
993 
994 static void
995 kerneldumpgz_destroy(struct dumperinfo *di)
996 {
997 	struct kerneldumpgz *kdgz;
998 
999 	kdgz = di->kdgz;
1000 	if (kdgz == NULL)
1001 		return;
1002 	gzio_fini(kdgz->kdgz_stream);
1003 	explicit_bzero(kdgz->kdgz_buf, di->maxiosize);
1004 	free(kdgz->kdgz_buf, M_DUMPER);
1005 	free(kdgz, M_DUMPER);
1006 }
1007 #endif /* GZIO */
1008 
1009 /* Registration of dumpers */
1010 int
1011 set_dumper(struct dumperinfo *di, const char *devname, struct thread *td,
1012     uint8_t compression, uint8_t encryption, const uint8_t *key,
1013     uint32_t encryptedkeysize, const uint8_t *encryptedkey)
1014 {
1015 	size_t wantcopy;
1016 	int error;
1017 
1018 	error = priv_check(td, PRIV_SETDUMPER);
1019 	if (error != 0)
1020 		return (error);
1021 
1022 	if (di == NULL) {
1023 		error = 0;
1024 		goto cleanup;
1025 	}
1026 	if (dumper.dumper != NULL)
1027 		return (EBUSY);
1028 	dumper = *di;
1029 	dumper.blockbuf = NULL;
1030 	dumper.kdc = NULL;
1031 	dumper.kdgz = NULL;
1032 
1033 	if (encryption != KERNELDUMP_ENC_NONE) {
1034 #ifdef EKCD
1035 		dumper.kdc = kerneldumpcrypto_create(di->blocksize, encryption,
1036 		    key, encryptedkeysize, encryptedkey);
1037 		if (dumper.kdc == NULL) {
1038 			error = EINVAL;
1039 			goto cleanup;
1040 		}
1041 #else
1042 		error = EOPNOTSUPP;
1043 		goto cleanup;
1044 #endif
1045 	}
1046 
1047 	wantcopy = strlcpy(dumpdevname, devname, sizeof(dumpdevname));
1048 	if (wantcopy >= sizeof(dumpdevname)) {
1049 		printf("set_dumper: device name truncated from '%s' -> '%s'\n",
1050 		    devname, dumpdevname);
1051 	}
1052 
1053 	if (compression != KERNELDUMP_COMP_NONE) {
1054 #ifdef GZIO
1055 		/*
1056 		 * We currently can't support simultaneous encryption and
1057 		 * compression.
1058 		 */
1059 		if (encryption != KERNELDUMP_ENC_NONE) {
1060 			error = EOPNOTSUPP;
1061 			goto cleanup;
1062 		}
1063 		dumper.kdgz = kerneldumpgz_create(&dumper, compression);
1064 		if (dumper.kdgz == NULL) {
1065 			error = EINVAL;
1066 			goto cleanup;
1067 		}
1068 #else
1069 		error = EOPNOTSUPP;
1070 		goto cleanup;
1071 #endif
1072 	}
1073 
1074 	dumper.blockbuf = malloc(di->blocksize, M_DUMPER, M_WAITOK | M_ZERO);
1075 	return (0);
1076 cleanup:
1077 #ifdef EKCD
1078 	if (dumper.kdc != NULL) {
1079 		explicit_bzero(dumper.kdc, sizeof(*dumper.kdc) +
1080 		    dumper.kdc->kdc_dumpkeysize);
1081 		free(dumper.kdc, M_EKCD);
1082 	}
1083 #endif
1084 
1085 #ifdef GZIO
1086 	kerneldumpgz_destroy(&dumper);
1087 #endif
1088 
1089 	if (dumper.blockbuf != NULL) {
1090 		explicit_bzero(dumper.blockbuf, dumper.blocksize);
1091 		free(dumper.blockbuf, M_DUMPER);
1092 	}
1093 	explicit_bzero(&dumper, sizeof(dumper));
1094 	dumpdevname[0] = '\0';
1095 	return (error);
1096 }
1097 
1098 static int
1099 dump_check_bounds(struct dumperinfo *di, off_t offset, size_t length)
1100 {
1101 
1102 	if (length != 0 && (offset < di->mediaoffset ||
1103 	    offset - di->mediaoffset + length > di->mediasize)) {
1104 		printf("Attempt to write outside dump device boundaries.\n"
1105 	    "offset(%jd), mediaoffset(%jd), length(%ju), mediasize(%jd).\n",
1106 		    (intmax_t)offset, (intmax_t)di->mediaoffset,
1107 		    (uintmax_t)length, (intmax_t)di->mediasize);
1108 		return (ENOSPC);
1109 	}
1110 	if (length % di->blocksize != 0) {
1111 		printf("Attempt to write partial block of length %ju.\n",
1112 		    (uintmax_t)length);
1113 		return (EINVAL);
1114 	}
1115 	if (offset % di->blocksize != 0) {
1116 		printf("Attempt to write at unaligned offset %jd.\n",
1117 		    (intmax_t)offset);
1118 		return (EINVAL);
1119 	}
1120 
1121 	return (0);
1122 }
1123 
1124 #ifdef EKCD
1125 static int
1126 dump_encrypt(struct kerneldumpcrypto *kdc, uint8_t *buf, size_t size)
1127 {
1128 
1129 	switch (kdc->kdc_encryption) {
1130 	case KERNELDUMP_ENC_AES_256_CBC:
1131 		if (rijndael_blockEncrypt(&kdc->kdc_ci, &kdc->kdc_ki, buf,
1132 		    8 * size, buf) <= 0) {
1133 			return (EIO);
1134 		}
1135 		if (rijndael_cipherInit(&kdc->kdc_ci, MODE_CBC,
1136 		    buf + size - 16 /* IV size for AES-256-CBC */) <= 0) {
1137 			return (EIO);
1138 		}
1139 		break;
1140 	default:
1141 		return (EINVAL);
1142 	}
1143 
1144 	return (0);
1145 }
1146 
1147 /* Encrypt data and call dumper. */
1148 static int
1149 dump_encrypted_write(struct dumperinfo *di, void *virtual,
1150     vm_offset_t physical, off_t offset, size_t length)
1151 {
1152 	static uint8_t buf[KERNELDUMP_BUFFER_SIZE];
1153 	struct kerneldumpcrypto *kdc;
1154 	int error;
1155 	size_t nbytes;
1156 
1157 	kdc = di->kdc;
1158 
1159 	while (length > 0) {
1160 		nbytes = MIN(length, sizeof(buf));
1161 		bcopy(virtual, buf, nbytes);
1162 
1163 		if (dump_encrypt(kdc, buf, nbytes) != 0)
1164 			return (EIO);
1165 
1166 		error = dump_write(di, buf, physical, offset, nbytes);
1167 		if (error != 0)
1168 			return (error);
1169 
1170 		offset += nbytes;
1171 		virtual = (void *)((uint8_t *)virtual + nbytes);
1172 		length -= nbytes;
1173 	}
1174 
1175 	return (0);
1176 }
1177 
1178 static int
1179 dump_write_key(struct dumperinfo *di, off_t offset)
1180 {
1181 	struct kerneldumpcrypto *kdc;
1182 
1183 	kdc = di->kdc;
1184 	if (kdc == NULL)
1185 		return (0);
1186 	return (dump_write(di, kdc->kdc_dumpkey, 0, offset,
1187 	    kdc->kdc_dumpkeysize));
1188 }
1189 #endif /* EKCD */
1190 
1191 #ifdef GZIO
1192 static int
1193 kerneldumpgz_write_cb(void *base, size_t length, off_t offset, void *arg)
1194 {
1195 	struct dumperinfo *di;
1196 	size_t resid, rlength;
1197 	int error;
1198 
1199 	di = arg;
1200 
1201 	if (length % di->blocksize != 0) {
1202 		/*
1203 		 * This must be the final write after flushing the compression
1204 		 * stream. Write as many full blocks as possible and stash the
1205 		 * residual data in the dumper's block buffer. It will be
1206 		 * padded and written in dump_finish().
1207 		 */
1208 		rlength = rounddown(length, di->blocksize);
1209 		if (rlength != 0) {
1210 			error = _dump_append(di, base, 0, rlength);
1211 			if (error != 0)
1212 				return (error);
1213 		}
1214 		resid = length - rlength;
1215 		memmove(di->blockbuf, (uint8_t *)base + rlength, resid);
1216 		di->kdgz->kdgz_resid = resid;
1217 		return (EAGAIN);
1218 	}
1219 	return (_dump_append(di, base, 0, length));
1220 }
1221 #endif /* GZIO */
1222 
1223 /*
1224  * Write a kerneldumpheader at the specified offset. The header structure is 512
1225  * bytes in size, but we must pad to the device sector size.
1226  */
1227 static int
1228 dump_write_header(struct dumperinfo *di, struct kerneldumpheader *kdh,
1229     off_t offset)
1230 {
1231 	void *buf;
1232 	size_t hdrsz;
1233 
1234 	hdrsz = sizeof(*kdh);
1235 	if (hdrsz > di->blocksize)
1236 		return (ENOMEM);
1237 
1238 	if (hdrsz == di->blocksize)
1239 		buf = kdh;
1240 	else {
1241 		buf = di->blockbuf;
1242 		memset(buf, 0, di->blocksize);
1243 		memcpy(buf, kdh, hdrsz);
1244 	}
1245 
1246 	return (dump_write(di, buf, 0, offset, di->blocksize));
1247 }
1248 
1249 /*
1250  * Don't touch the first SIZEOF_METADATA bytes on the dump device.  This is to
1251  * protect us from metadata and metadata from us.
1252  */
1253 #define	SIZEOF_METADATA		(64 * 1024)
1254 
1255 /*
1256  * Do some preliminary setup for a kernel dump: initialize state for encryption,
1257  * if requested, and make sure that we have enough space on the dump device.
1258  *
1259  * We set things up so that the dump ends before the last sector of the dump
1260  * device, at which the trailing header is written.
1261  *
1262  *     +-----------+------+-----+----------------------------+------+
1263  *     |           | lhdr | key |    ... kernel dump ...     | thdr |
1264  *     +-----------+------+-----+----------------------------+------+
1265  *                   1 blk  opt <------- dump extent --------> 1 blk
1266  *
1267  * Dumps written using dump_append() start at the beginning of the extent.
1268  * Uncompressed dumps will use the entire extent, but compressed dumps typically
1269  * will not. The true length of the dump is recorded in the leading and trailing
1270  * headers once the dump has been completed.
1271  */
1272 int
1273 dump_start(struct dumperinfo *di, struct kerneldumpheader *kdh)
1274 {
1275 	uint64_t dumpextent;
1276 	uint32_t keysize;
1277 
1278 #ifdef EKCD
1279 	int error = kerneldumpcrypto_init(di->kdc);
1280 	if (error != 0)
1281 		return (error);
1282 	keysize = kerneldumpcrypto_dumpkeysize(di->kdc);
1283 #else
1284 	keysize = 0;
1285 #endif
1286 
1287 	dumpextent = dtoh64(kdh->dumpextent);
1288 	if (di->mediasize < SIZEOF_METADATA + dumpextent + 2 * di->blocksize +
1289 	    keysize) {
1290 #ifdef GZIO
1291 		if (di->kdgz != NULL) {
1292 			/*
1293 			 * We don't yet know how much space the compressed dump
1294 			 * will occupy, so try to use the whole swap partition
1295 			 * (minus the first 64KB) in the hope that the
1296 			 * compressed dump will fit. If that doesn't turn out to
1297 			 * be enouch, the bounds checking in dump_write()
1298 			 * will catch us and cause the dump to fail.
1299 			 */
1300 			dumpextent = di->mediasize - SIZEOF_METADATA -
1301 			    2 * di->blocksize - keysize;
1302 			kdh->dumpextent = htod64(dumpextent);
1303 		} else
1304 #endif
1305 			return (E2BIG);
1306 	}
1307 
1308 	/* The offset at which to begin writing the dump. */
1309 	di->dumpoff = di->mediaoffset + di->mediasize - di->blocksize -
1310 	    dumpextent;
1311 
1312 	return (0);
1313 }
1314 
1315 static int
1316 _dump_append(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1317     size_t length)
1318 {
1319 	int error;
1320 
1321 #ifdef EKCD
1322 	if (di->kdc != NULL)
1323 		error = dump_encrypted_write(di, virtual, physical, di->dumpoff,
1324 		    length);
1325 	else
1326 #endif
1327 		error = dump_write(di, virtual, physical, di->dumpoff, length);
1328 	if (error == 0)
1329 		di->dumpoff += length;
1330 	return (error);
1331 }
1332 
1333 /*
1334  * Write to the dump device starting at dumpoff. When compression is enabled,
1335  * writes to the device will be performed using a callback that gets invoked
1336  * when the compression stream's output buffer is full.
1337  */
1338 int
1339 dump_append(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1340     size_t length)
1341 {
1342 #ifdef GZIO
1343 	void *buf;
1344 
1345 	if (di->kdgz != NULL) {
1346 		/* Bounce through a buffer to avoid gzip CRC errors. */
1347 		if (length > di->maxiosize)
1348 			return (EINVAL);
1349 		buf = di->kdgz->kdgz_buf;
1350 		memmove(buf, virtual, length);
1351 		return (gzio_write(di->kdgz->kdgz_stream, buf, length));
1352 	}
1353 #endif
1354 	return (_dump_append(di, virtual, physical, length));
1355 }
1356 
1357 /*
1358  * Write to the dump device at the specified offset.
1359  */
1360 int
1361 dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
1362     off_t offset, size_t length)
1363 {
1364 	int error;
1365 
1366 	error = dump_check_bounds(di, offset, length);
1367 	if (error != 0)
1368 		return (error);
1369 	return (di->dumper(di->priv, virtual, physical, offset, length));
1370 }
1371 
1372 /*
1373  * Perform kernel dump finalization: flush the compression stream, if necessary,
1374  * write the leading and trailing kernel dump headers now that we know the true
1375  * length of the dump, and optionally write the encryption key following the
1376  * leading header.
1377  */
1378 int
1379 dump_finish(struct dumperinfo *di, struct kerneldumpheader *kdh)
1380 {
1381 	uint64_t extent;
1382 	uint32_t keysize;
1383 	int error;
1384 
1385 	extent = dtoh64(kdh->dumpextent);
1386 
1387 #ifdef EKCD
1388 	keysize = kerneldumpcrypto_dumpkeysize(di->kdc);
1389 #else
1390 	keysize = 0;
1391 #endif
1392 
1393 #ifdef GZIO
1394 	if (di->kdgz != NULL) {
1395 		error = gzio_flush(di->kdgz->kdgz_stream);
1396 		if (error == EAGAIN) {
1397 			/* We have residual data in di->blockbuf. */
1398 			error = dump_write(di, di->blockbuf, 0, di->dumpoff,
1399 			    di->blocksize);
1400 			di->dumpoff += di->kdgz->kdgz_resid;
1401 			di->kdgz->kdgz_resid = 0;
1402 		}
1403 		if (error != 0)
1404 			return (error);
1405 
1406 		/*
1407 		 * We now know the size of the compressed dump, so update the
1408 		 * header accordingly and recompute parity.
1409 		 */
1410 		kdh->dumplength = htod64(di->dumpoff -
1411 		    (di->mediaoffset + di->mediasize - di->blocksize - extent));
1412 		kdh->parity = 0;
1413 		kdh->parity = kerneldump_parity(kdh);
1414 
1415 		gzio_reset(di->kdgz->kdgz_stream);
1416 	}
1417 #endif
1418 
1419 	/*
1420 	 * Write kerneldump headers at the beginning and end of the dump extent.
1421 	 * Write the key after the leading header.
1422 	 */
1423 	error = dump_write_header(di, kdh,
1424 	    di->mediaoffset + di->mediasize - 2 * di->blocksize - extent -
1425 	    keysize);
1426 	if (error != 0)
1427 		return (error);
1428 
1429 #ifdef EKCD
1430 	error = dump_write_key(di,
1431 	    di->mediaoffset + di->mediasize - di->blocksize - extent - keysize);
1432 	if (error != 0)
1433 		return (error);
1434 #endif
1435 
1436 	error = dump_write_header(di, kdh,
1437 	    di->mediaoffset + di->mediasize - di->blocksize);
1438 	if (error != 0)
1439 		return (error);
1440 
1441 	(void)dump_write(di, NULL, 0, 0, 0);
1442 	return (0);
1443 }
1444 
1445 void
1446 dump_init_header(const struct dumperinfo *di, struct kerneldumpheader *kdh,
1447     char *magic, uint32_t archver, uint64_t dumplen)
1448 {
1449 	size_t dstsize;
1450 
1451 	bzero(kdh, sizeof(*kdh));
1452 	strlcpy(kdh->magic, magic, sizeof(kdh->magic));
1453 	strlcpy(kdh->architecture, MACHINE_ARCH, sizeof(kdh->architecture));
1454 	kdh->version = htod32(KERNELDUMPVERSION);
1455 	kdh->architectureversion = htod32(archver);
1456 	kdh->dumplength = htod64(dumplen);
1457 	kdh->dumpextent = kdh->dumplength;
1458 	kdh->dumptime = htod64(time_second);
1459 #ifdef EKCD
1460 	kdh->dumpkeysize = htod32(kerneldumpcrypto_dumpkeysize(di->kdc));
1461 #else
1462 	kdh->dumpkeysize = 0;
1463 #endif
1464 	kdh->blocksize = htod32(di->blocksize);
1465 	strlcpy(kdh->hostname, prison0.pr_hostname, sizeof(kdh->hostname));
1466 	dstsize = sizeof(kdh->versionstring);
1467 	if (strlcpy(kdh->versionstring, version, dstsize) >= dstsize)
1468 		kdh->versionstring[dstsize - 2] = '\n';
1469 	if (panicstr != NULL)
1470 		strlcpy(kdh->panicstring, panicstr, sizeof(kdh->panicstring));
1471 #ifdef GZIO
1472 	if (di->kdgz != NULL)
1473 		kdh->compression = KERNELDUMP_COMP_GZIP;
1474 #endif
1475 	kdh->parity = kerneldump_parity(kdh);
1476 }
1477 
1478 #ifdef DDB
1479 DB_SHOW_COMMAND(panic, db_show_panic)
1480 {
1481 
1482 	if (panicstr == NULL)
1483 		db_printf("panicstr not set\n");
1484 	else
1485 		db_printf("panic: %s\n", panicstr);
1486 }
1487 #endif
1488