xref: /netbsd-src/sys/kern/subr_prf.c (revision 7863ba460b0a05b553c754e5dbc29247dddec322)
1 /*	$NetBSD: subr_prf.c,v 1.165 2018/04/01 19:29:43 christos Exp $	*/
2 
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  *	@(#)subr_prf.c	8.4 (Berkeley) 5/4/95
37  */
38 
39 #include <sys/cdefs.h>
40 __KERNEL_RCSID(0, "$NetBSD: subr_prf.c,v 1.165 2018/04/01 19:29:43 christos Exp $");
41 
42 #ifdef _KERNEL_OPT
43 #include "opt_ddb.h"
44 #include "opt_ipkdb.h"
45 #include "opt_kgdb.h"
46 #include "opt_dump.h"
47 #include "opt_rnd_printf.h"
48 #endif
49 
50 #include <sys/param.h>
51 #include <sys/stdint.h>
52 #include <sys/systm.h>
53 #include <sys/buf.h>
54 #include <sys/device.h>
55 #include <sys/reboot.h>
56 #include <sys/msgbuf.h>
57 #include <sys/proc.h>
58 #include <sys/ioctl.h>
59 #include <sys/vnode.h>
60 #include <sys/file.h>
61 #include <sys/tty.h>
62 #include <sys/tprintf.h>
63 #include <sys/spldebug.h>
64 #include <sys/syslog.h>
65 #include <sys/kprintf.h>
66 #include <sys/atomic.h>
67 #include <sys/kernel.h>
68 #include <sys/cpu.h>
69 #include <sys/sha2.h>
70 #include <sys/rndsource.h>
71 
72 #include <dev/cons.h>
73 
74 #include <net/if.h>
75 
76 #ifdef IPKDB
77 #include <ipkdb/ipkdb.h>
78 #endif
79 
80 static kmutex_t kprintf_mtx;
81 static bool kprintf_inited = false;
82 
83 #ifdef KGDB
84 #include <sys/kgdb.h>
85 #endif
86 
87 #ifdef DDB
88 #include <ddb/ddbvar.h>		/* db_panic */
89 #include <ddb/db_output.h>	/* db_printf, db_putchar prototypes */
90 #endif
91 
92 
93 /*
94  * defines
95  */
96 #define KLOG_PRI	0x80000000
97 
98 
99 /*
100  * local prototypes
101  */
102 
103 static void	 putchar(int, int, struct tty *);
104 
105 
106 /*
107  * globals
108  */
109 
110 extern	struct tty *constty;	/* pointer to console "window" tty */
111 extern	int log_open;	/* subr_log: is /dev/klog open? */
112 extern	krndsource_t	rnd_printf_source;
113 const	char *panicstr; /* arg to first call to panic (used as a flag
114 			   to indicate that panic has already been called). */
115 struct cpu_info *paniccpu;	/* cpu that first paniced */
116 long	panicstart, panicend;	/* position in the msgbuf of the start and
117 				   end of the formatted panicstr. */
118 int	doing_shutdown;	/* set to indicate shutdown in progress */
119 
120 #ifdef RND_PRINTF
121 static bool kprintf_inited_callout = false;
122 static SHA512_CTX kprnd_sha;
123 static uint8_t kprnd_accum[SHA512_DIGEST_LENGTH];
124 static int kprnd_added;
125 
126 static struct callout kprnd_callout;
127 #endif
128 
129 #ifndef	DUMP_ON_PANIC
130 #define	DUMP_ON_PANIC	1
131 #endif
132 int	dumponpanic = DUMP_ON_PANIC;
133 
134 /*
135  * v_putc: routine to putc on virtual console
136  *
137  * the v_putc pointer can be used to redirect the console cnputc elsewhere
138  * [e.g. to a "virtual console"].
139  */
140 
141 void (*v_putc)(int) = cnputc;	/* start with cnputc (normal cons) */
142 void (*v_flush)(void) = cnflush;	/* start with cnflush (normal cons) */
143 
144 const char hexdigits[] = "0123456789abcdef";
145 const char HEXDIGITS[] = "0123456789ABCDEF";
146 
147 
148 /*
149  * functions
150  */
151 
152 #ifdef RND_PRINTF
153 static void kprintf_rnd_get(size_t bytes, void *priv)
154 {
155 	if (kprnd_added)  {
156 		KASSERT(kprintf_inited);
157 		if (mutex_tryenter(&kprintf_mtx)) {
158 			SHA512_Final(kprnd_accum, &kprnd_sha);
159 			rnd_add_data(&rnd_printf_source,
160 				     kprnd_accum, sizeof(kprnd_accum), 0);
161 			kprnd_added = 0;
162 			/* This, we must do, since we called _Final. */
163 			SHA512_Init(&kprnd_sha);
164 			/* This is optional but seems useful. */
165 			SHA512_Update(&kprnd_sha, kprnd_accum,
166 				      sizeof(kprnd_accum));
167 			mutex_exit(&kprintf_mtx);
168 		}
169 	}
170 }
171 
172 static void kprintf_rnd_callout(void *arg)
173 {
174 	kprintf_rnd_get(0, NULL);
175 	callout_schedule(&kprnd_callout, hz);
176 }
177 
178 #endif
179 
180 /*
181  * Locking is inited fairly early in MI bootstrap.  Before that
182  * prints are done unlocked.  But that doesn't really matter,
183  * since nothing can preempt us before interrupts are enabled.
184  */
185 void
186 kprintf_init(void)
187 {
188 
189 	KASSERT(!kprintf_inited && cold); /* not foolproof, but ... */
190 #ifdef RND_PRINTF
191 	SHA512_Init(&kprnd_sha);
192 #endif
193 	mutex_init(&kprintf_mtx, MUTEX_DEFAULT, IPL_HIGH);
194 	kprintf_inited = true;
195 }
196 
197 #ifdef RND_PRINTF
198 void
199 kprintf_init_callout(void)
200 {
201 	KASSERT(!kprintf_inited_callout);
202 	callout_init(&kprnd_callout, CALLOUT_MPSAFE);
203 	callout_setfunc(&kprnd_callout, kprintf_rnd_callout, NULL);
204 	callout_schedule(&kprnd_callout, hz);
205 	kprintf_inited_callout = true;
206 }
207 #endif
208 
209 void
210 kprintf_lock(void)
211 {
212 
213 	if (__predict_true(kprintf_inited))
214 		mutex_enter(&kprintf_mtx);
215 }
216 
217 void
218 kprintf_unlock(void)
219 {
220 
221 	if (__predict_true(kprintf_inited)) {
222 		/* assert kprintf wasn't somehow inited while we were in */
223 		KASSERT(mutex_owned(&kprintf_mtx));
224 		mutex_exit(&kprintf_mtx);
225 	}
226 }
227 
228 /*
229  * twiddle: spin a little propellor on the console.
230  */
231 
232 void
233 twiddle(void)
234 {
235 	static const char twiddle_chars[] = "|/-\\";
236 	static int pos;
237 
238 	kprintf_lock();
239 
240 	putchar(twiddle_chars[pos++ & 3], TOCONS, NULL);
241 	putchar('\b', TOCONS, NULL);
242 
243 	kprintf_unlock();
244 }
245 
246 /*
247  * panic: handle an unresolvable fatal error
248  *
249  * prints "panic: <message>" and reboots.   if called twice (i.e. recursive
250  * call) we avoid trying to dump and just reboot (to avoid recursive panics).
251  */
252 
253 void
254 panic(const char *fmt, ...)
255 {
256 	va_list ap;
257 
258 	va_start(ap, fmt);
259 	vpanic(fmt, ap);
260 	va_end(ap);
261 }
262 
263 void
264 vpanic(const char *fmt, va_list ap)
265 {
266 	CPU_INFO_ITERATOR cii;
267 	struct cpu_info *ci, *oci;
268 	int bootopt;
269 	static char scratchstr[384]; /* stores panic message */
270 
271 	spldebug_stop();
272 
273 	if (lwp0.l_cpu && curlwp) {
274 		/*
275 		 * Disable preemption.  If already panicing on another CPU, sit
276 		 * here and spin until the system is rebooted.  Allow the CPU that
277 		 * first paniced to panic again.
278 		 */
279 		kpreempt_disable();
280 		ci = curcpu();
281 		oci = atomic_cas_ptr((void *)&paniccpu, NULL, ci);
282 		if (oci != NULL && oci != ci) {
283 			/* Give interrupts a chance to try and prevent deadlock. */
284 			for (;;) {
285 #ifndef _RUMPKERNEL /* XXXpooka: temporary build fix, see kern/40505 */
286 				DELAY(10);
287 #endif /* _RUMPKERNEL */
288 			}
289 		}
290 
291 		/*
292 		 * Convert the current thread to a bound thread and prevent all
293 		 * CPUs from scheduling unbound jobs.  Do so without taking any
294 		 * locks.
295 		 */
296 		curlwp->l_pflag |= LP_BOUND;
297 		for (CPU_INFO_FOREACH(cii, ci)) {
298 			ci->ci_schedstate.spc_flags |= SPCF_OFFLINE;
299 		}
300 	}
301 
302 	bootopt = RB_AUTOBOOT | RB_NOSYNC;
303 	if (!doing_shutdown) {
304 		if (dumponpanic)
305 			bootopt |= RB_DUMP;
306 	} else
307 		printf("Skipping crash dump on recursive panic\n");
308 
309 	doing_shutdown = 1;
310 
311 	if (logenabled(msgbufp))
312 		panicstart = msgbufp->msg_bufx;
313 
314 	printf("panic: ");
315 	if (panicstr == NULL) {
316 		/* first time in panic - store fmt first for precaution */
317 		panicstr = fmt;
318 
319 		vsnprintf(scratchstr, sizeof(scratchstr), fmt, ap);
320 		printf("%s", scratchstr);
321 		panicstr = scratchstr;
322 	} else {
323 		vprintf(fmt, ap);
324 	}
325 	printf("\n");
326 
327 	if (logenabled(msgbufp))
328 		panicend = msgbufp->msg_bufx;
329 
330 #ifdef IPKDB
331 	ipkdb_panic();
332 #endif
333 #ifdef KGDB
334 	kgdb_panic();
335 #endif
336 #ifdef KADB
337 	if (boothowto & RB_KDB)
338 		kdbpanic();
339 #endif
340 #ifdef DDB
341 	db_panic();
342 #endif
343 	cpu_reboot(bootopt, NULL);
344 }
345 
346 /*
347  * kernel logging functions: log, logpri, addlog
348  */
349 
350 /*
351  * log: write to the log buffer
352  *
353  * => will not sleep [so safe to call from interrupt]
354  * => will log to console if /dev/klog isn't open
355  */
356 
357 void
358 log(int level, const char *fmt, ...)
359 {
360 	va_list ap;
361 
362 	kprintf_lock();
363 
364 	klogpri(level);		/* log the level first */
365 	va_start(ap, fmt);
366 	kprintf(fmt, TOLOG, NULL, NULL, ap);
367 	va_end(ap);
368 	if (!log_open) {
369 		va_start(ap, fmt);
370 		kprintf(fmt, TOCONS, NULL, NULL, ap);
371 		va_end(ap);
372 	}
373 
374 	kprintf_unlock();
375 
376 	logwakeup();		/* wake up anyone waiting for log msgs */
377 }
378 
379 /*
380  * vlog: write to the log buffer [already have va_list]
381  */
382 
383 void
384 vlog(int level, const char *fmt, va_list ap)
385 {
386 	va_list cap;
387 
388 	va_copy(cap, ap);
389 	kprintf_lock();
390 
391 	klogpri(level);		/* log the level first */
392 	kprintf(fmt, TOLOG, NULL, NULL, ap);
393 	if (!log_open)
394 		kprintf(fmt, TOCONS, NULL, NULL, cap);
395 
396 	kprintf_unlock();
397 	va_end(cap);
398 
399 	logwakeup();		/* wake up anyone waiting for log msgs */
400 }
401 
402 /*
403  * logpri: log the priority level to the klog
404  */
405 
406 void
407 logpri(int level)
408 {
409 
410 	kprintf_lock();
411 	klogpri(level);
412 	kprintf_unlock();
413 }
414 
415 /*
416  * Note: we must be in the mutex here!
417  */
418 void
419 klogpri(int level)
420 {
421 	KASSERT((level & KLOG_PRI) == 0);
422 
423 	putchar(level | KLOG_PRI, TOLOG, NULL);
424 }
425 
426 /*
427  * addlog: add info to previous log message
428  */
429 
430 void
431 addlog(const char *fmt, ...)
432 {
433 	va_list ap;
434 
435 	kprintf_lock();
436 
437 	va_start(ap, fmt);
438 	kprintf(fmt, TOLOG, NULL, NULL, ap);
439 	va_end(ap);
440 	if (!log_open) {
441 		va_start(ap, fmt);
442 		kprintf(fmt, TOCONS, NULL, NULL, ap);
443 		va_end(ap);
444 	}
445 
446 	kprintf_unlock();
447 
448 	logwakeup();
449 }
450 
451 static void
452 putone(int c, int flags, struct tty *tp)
453 {
454 	if (panicstr)
455 		constty = NULL;
456 
457 	if ((flags & TOCONS) && tp == NULL && constty) {
458 		tp = constty;
459 		flags |= TOTTY;
460 	}
461 	if ((flags & TOTTY) && tp &&
462 	    tputchar(c, flags, tp) < 0 &&
463 	    (flags & TOCONS) && tp == constty)
464 		constty = NULL;
465 	if ((flags & TOLOG) &&
466 	    c != '\0' && c != '\r' && c != 0177)
467 	    	logputchar(c);
468 	if ((flags & TOCONS) && constty == NULL && c != '\0')
469 		(*v_putc)(c);
470 }
471 
472 static void
473 putlogpri(int level)
474 {
475 	char *p;
476 	char snbuf[KPRINTF_BUFSIZE];
477 
478 	putone('<', TOLOG, NULL);
479 	snprintf(snbuf, sizeof(snbuf), "%d", level);
480 	for (p = snbuf ; *p ; p++)
481 		putone(*p, TOLOG, NULL);
482 	putone('>', TOLOG, NULL);
483 }
484 
485 #ifdef KLOG_TIMESTAMP
486 static int needtstamp = 1;
487 
488 static void
489 addtstamp(int flags, struct tty *tp)
490 {
491 	char buf[64];
492 	struct timespec ts;
493 	int n;
494 
495 	getnanouptime(&ts);
496 	n = snprintf(buf, sizeof(buf), "[% 9jd.%.9ld] ",
497 	    (intptr_t)ts.tv_sec, ts.tv_nsec);
498 
499 	for (int i = 0; i < n; i++)
500 		putone(buf[i], flags, tp);
501 }
502 #endif
503 
504 /*
505  * putchar: print a single character on console or user terminal.
506  *
507  * => if console, then the last MSGBUFS chars are saved in msgbuf
508  *	for inspection later (e.g. dmesg/syslog)
509  * => we must already be in the mutex!
510  */
511 static void
512 putchar(int c, int flags, struct tty *tp)
513 {
514 	if (c & KLOG_PRI) {
515 		putlogpri(c & ~KLOG_PRI);
516 		return;
517 	}
518 
519 #ifdef KLOG_TIMESTAMP
520 	if (needtstamp) {
521 		addtstamp(flags, tp);
522 		needtstamp = 0;
523 	}
524 
525 	if (c == '\n')
526 		needtstamp++;
527 #endif
528 	putone(c, flags, tp);
529 
530 #ifdef DDB
531 	if (flags & TODDB) {
532 		db_putchar(c);
533 		return;
534 	}
535 #endif
536 
537 #ifdef RND_PRINTF
538 	if (__predict_true(kprintf_inited)) {
539 		static uint8_t rbuf[SHA512_BLOCK_LENGTH];
540 		static int cursor;
541 
542 		rbuf[cursor] = c;
543 		if (cursor == sizeof(rbuf) - 1) {
544 			SHA512_Update(&kprnd_sha, rbuf, sizeof(rbuf));
545 			kprnd_added++;
546 			cursor = 0;
547 		} else {
548 			cursor++;
549 		}
550 	}
551 #endif
552 }
553 
554 /*
555  * tablefull: warn that a system table is full
556  */
557 
558 void
559 tablefull(const char *tab, const char *hint)
560 {
561 	if (hint)
562 		log(LOG_ERR, "%s: table is full - %s\n", tab, hint);
563 	else
564 		log(LOG_ERR, "%s: table is full\n", tab);
565 }
566 
567 
568 /*
569  * uprintf: print to the controlling tty of the current process
570  *
571  * => we may block if the tty queue is full
572  * => no message is printed if the queue doesn't clear in a reasonable
573  *	time
574  */
575 
576 void
577 uprintf(const char *fmt, ...)
578 {
579 	struct proc *p = curproc;
580 	va_list ap;
581 
582 	/* mutex_enter(proc_lock); XXXSMP */
583 
584 	if (p->p_lflag & PL_CONTROLT && p->p_session->s_ttyvp) {
585 		/* No mutex needed; going to process TTY. */
586 		va_start(ap, fmt);
587 		kprintf(fmt, TOTTY, p->p_session->s_ttyp, NULL, ap);
588 		va_end(ap);
589 	}
590 
591 	/* mutex_exit(proc_lock); XXXSMP */
592 }
593 
594 void
595 uprintf_locked(const char *fmt, ...)
596 {
597 	struct proc *p = curproc;
598 	va_list ap;
599 
600 	if (p->p_lflag & PL_CONTROLT && p->p_session->s_ttyvp) {
601 		/* No mutex needed; going to process TTY. */
602 		va_start(ap, fmt);
603 		kprintf(fmt, TOTTY, p->p_session->s_ttyp, NULL, ap);
604 		va_end(ap);
605 	}
606 }
607 
608 /*
609  * tprintf functions: used to send messages to a specific process
610  *
611  * usage:
612  *   get a tpr_t handle on a process "p" by using "tprintf_open(p)"
613  *   use the handle when calling "tprintf"
614  *   when done, do a "tprintf_close" to drop the handle
615  */
616 
617 /*
618  * tprintf_open: get a tprintf handle on a process "p"
619  *
620  * => returns NULL if process can't be printed to
621  */
622 
623 tpr_t
624 tprintf_open(struct proc *p)
625 {
626 	tpr_t cookie;
627 
628 	cookie = NULL;
629 
630 	mutex_enter(proc_lock);
631 	if (p->p_lflag & PL_CONTROLT && p->p_session->s_ttyvp) {
632 		proc_sesshold(p->p_session);
633 		cookie = (tpr_t)p->p_session;
634 	}
635 	mutex_exit(proc_lock);
636 
637 	return cookie;
638 }
639 
640 /*
641  * tprintf_close: dispose of a tprintf handle obtained with tprintf_open
642  */
643 
644 void
645 tprintf_close(tpr_t sess)
646 {
647 
648 	if (sess) {
649 		mutex_enter(proc_lock);
650 		/* Releases proc_lock. */
651 		proc_sessrele((struct session *)sess);
652 	}
653 }
654 
655 /*
656  * tprintf: given tprintf handle to a process [obtained with tprintf_open],
657  * send a message to the controlling tty for that process.
658  *
659  * => also sends message to /dev/klog
660  */
661 void
662 tprintf(tpr_t tpr, const char *fmt, ...)
663 {
664 	struct session *sess = (struct session *)tpr;
665 	struct tty *tp = NULL;
666 	int flags = TOLOG;
667 	va_list ap;
668 
669 	/* mutex_enter(proc_lock); XXXSMP */
670 	if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
671 		flags |= TOTTY;
672 		tp = sess->s_ttyp;
673 	}
674 
675 	kprintf_lock();
676 
677 	klogpri(LOG_INFO);
678 	va_start(ap, fmt);
679 	kprintf(fmt, flags, tp, NULL, ap);
680 	va_end(ap);
681 
682 	kprintf_unlock();
683 	/* mutex_exit(proc_lock);	XXXSMP */
684 
685 	logwakeup();
686 }
687 
688 
689 /*
690  * ttyprintf: send a message to a specific tty
691  *
692  * => should be used only by tty driver or anything that knows the
693  *    underlying tty will not be revoked(2)'d away.  [otherwise,
694  *    use tprintf]
695  */
696 void
697 ttyprintf(struct tty *tp, const char *fmt, ...)
698 {
699 	va_list ap;
700 
701 	/* No mutex needed; going to process TTY. */
702 	va_start(ap, fmt);
703 	kprintf(fmt, TOTTY, tp, NULL, ap);
704 	va_end(ap);
705 }
706 
707 #ifdef DDB
708 
709 /*
710  * db_printf: printf for DDB (via db_putchar)
711  */
712 
713 void
714 db_printf(const char *fmt, ...)
715 {
716 	va_list ap;
717 
718 	/* No mutex needed; DDB pauses all processors. */
719 	va_start(ap, fmt);
720 	kprintf(fmt, TODDB, NULL, NULL, ap);
721 	va_end(ap);
722 
723 	if (db_tee_msgbuf) {
724 		va_start(ap, fmt);
725 		kprintf(fmt, TOLOG, NULL, NULL, ap);
726 		va_end(ap);
727 	}
728 }
729 
730 void
731 db_vprintf(const char *fmt, va_list ap)
732 {
733 	va_list cap;
734 
735 	va_copy(cap, ap);
736 	/* No mutex needed; DDB pauses all processors. */
737 	kprintf(fmt, TODDB, NULL, NULL, ap);
738 	if (db_tee_msgbuf)
739 		kprintf(fmt, TOLOG, NULL, NULL, cap);
740 	va_end(cap);
741 }
742 
743 #endif /* DDB */
744 
745 static void
746 kprintf_internal(const char *fmt, int oflags, void *vp, char *sbuf, ...)
747 {
748 	va_list ap;
749 
750 	va_start(ap, sbuf);
751 	(void)kprintf(fmt, oflags, vp, sbuf, ap);
752 	va_end(ap);
753 }
754 
755 /*
756  * Device autoconfiguration printf routines.  These change their
757  * behavior based on the AB_* flags in boothowto.  If AB_SILENT
758  * is set, messages never go to the console (but they still always
759  * go to the log).  AB_VERBOSE overrides AB_SILENT.
760  */
761 
762 /*
763  * aprint_normal: Send to console unless AB_QUIET.  Always goes
764  * to the log.
765  */
766 static void
767 aprint_normal_internal(const char *prefix, const char *fmt, va_list ap)
768 {
769 	int flags = TOLOG;
770 
771 	if ((boothowto & (AB_SILENT|AB_QUIET)) == 0 ||
772 	    (boothowto & AB_VERBOSE) != 0)
773 		flags |= TOCONS;
774 
775 	kprintf_lock();
776 
777 	if (prefix)
778 		kprintf_internal("%s: ", flags, NULL, NULL, prefix);
779 	kprintf(fmt, flags, NULL, NULL, ap);
780 
781 	kprintf_unlock();
782 
783 	if (!panicstr)
784 		logwakeup();
785 }
786 
787 void
788 aprint_normal(const char *fmt, ...)
789 {
790 	va_list ap;
791 
792 	va_start(ap, fmt);
793 	aprint_normal_internal(NULL, fmt, ap);
794 	va_end(ap);
795 }
796 
797 void
798 aprint_normal_dev(device_t dv, const char *fmt, ...)
799 {
800 	va_list ap;
801 
802 	va_start(ap, fmt);
803 	aprint_normal_internal(device_xname(dv), fmt, ap);
804 	va_end(ap);
805 }
806 
807 void
808 aprint_normal_ifnet(struct ifnet *ifp, const char *fmt, ...)
809 {
810 	va_list ap;
811 
812 	va_start(ap, fmt);
813 	aprint_normal_internal(ifp->if_xname, fmt, ap);
814 	va_end(ap);
815 }
816 
817 /*
818  * aprint_error: Send to console unless AB_QUIET.  Always goes
819  * to the log.  Also counts the number of times called so other
820  * parts of the kernel can report the number of errors during a
821  * given phase of system startup.
822  */
823 static int aprint_error_count;
824 
825 int
826 aprint_get_error_count(void)
827 {
828 	int count;
829 
830 	kprintf_lock();
831 
832 	count = aprint_error_count;
833 	aprint_error_count = 0;
834 
835 	kprintf_unlock();
836 
837 	return (count);
838 }
839 
840 static void
841 aprint_error_internal(const char *prefix, const char *fmt, va_list ap)
842 {
843 	int flags = TOLOG;
844 
845 	if ((boothowto & (AB_SILENT|AB_QUIET)) == 0 ||
846 	    (boothowto & AB_VERBOSE) != 0)
847 		flags |= TOCONS;
848 
849 	kprintf_lock();
850 
851 	aprint_error_count++;
852 
853 	if (prefix)
854 		kprintf_internal("%s: ", flags, NULL, NULL, prefix);
855 	kprintf(fmt, flags, NULL, NULL, ap);
856 
857 	kprintf_unlock();
858 
859 	if (!panicstr)
860 		logwakeup();
861 }
862 
863 void
864 aprint_error(const char *fmt, ...)
865 {
866 	va_list ap;
867 
868 	va_start(ap, fmt);
869 	aprint_error_internal(NULL, fmt, ap);
870 	va_end(ap);
871 }
872 
873 void
874 aprint_error_dev(device_t dv, const char *fmt, ...)
875 {
876 	va_list ap;
877 
878 	va_start(ap, fmt);
879 	aprint_error_internal(device_xname(dv), fmt, ap);
880 	va_end(ap);
881 }
882 
883 void
884 aprint_error_ifnet(struct ifnet *ifp, const char *fmt, ...)
885 {
886 	va_list ap;
887 
888 	va_start(ap, fmt);
889 	aprint_error_internal(ifp->if_xname, fmt, ap);
890 	va_end(ap);
891 }
892 
893 /*
894  * aprint_naive: Send to console only if AB_QUIET.  Never goes
895  * to the log.
896  */
897 static void
898 aprint_naive_internal(const char *prefix, const char *fmt, va_list ap)
899 {
900 	if ((boothowto & (AB_QUIET|AB_SILENT|AB_VERBOSE)) != AB_QUIET)
901 		return;
902 
903 	kprintf_lock();
904 
905 	if (prefix)
906 		kprintf_internal("%s: ", TOCONS, NULL, NULL, prefix);
907 	kprintf(fmt, TOCONS, NULL, NULL, ap);
908 
909 	kprintf_unlock();
910 }
911 
912 void
913 aprint_naive(const char *fmt, ...)
914 {
915 	va_list ap;
916 
917 	va_start(ap, fmt);
918 	aprint_naive_internal(NULL, fmt, ap);
919 	va_end(ap);
920 }
921 
922 void
923 aprint_naive_dev(device_t dv, const char *fmt, ...)
924 {
925 	va_list ap;
926 
927 	va_start(ap, fmt);
928 	aprint_naive_internal(device_xname(dv), fmt, ap);
929 	va_end(ap);
930 }
931 
932 void
933 aprint_naive_ifnet(struct ifnet *ifp, const char *fmt, ...)
934 {
935 	va_list ap;
936 
937 	va_start(ap, fmt);
938 	aprint_naive_internal(ifp->if_xname, fmt, ap);
939 	va_end(ap);
940 }
941 
942 /*
943  * aprint_verbose: Send to console only if AB_VERBOSE.  Always
944  * goes to the log.
945  */
946 static void
947 aprint_verbose_internal(const char *prefix, const char *fmt, va_list ap)
948 {
949 	int flags = TOLOG;
950 
951 	if (boothowto & AB_VERBOSE)
952 		flags |= TOCONS;
953 
954 	kprintf_lock();
955 
956 	if (prefix)
957 		kprintf_internal("%s: ", flags, NULL, NULL, prefix);
958 	kprintf(fmt, flags, NULL, NULL, ap);
959 
960 	kprintf_unlock();
961 
962 	if (!panicstr)
963 		logwakeup();
964 }
965 
966 void
967 aprint_verbose(const char *fmt, ...)
968 {
969 	va_list ap;
970 
971 	va_start(ap, fmt);
972 	aprint_verbose_internal(NULL, fmt, ap);
973 	va_end(ap);
974 }
975 
976 void
977 aprint_verbose_dev(device_t dv, const char *fmt, ...)
978 {
979 	va_list ap;
980 
981 	va_start(ap, fmt);
982 	aprint_verbose_internal(device_xname(dv), fmt, ap);
983 	va_end(ap);
984 }
985 
986 void
987 aprint_verbose_ifnet(struct ifnet *ifp, const char *fmt, ...)
988 {
989 	va_list ap;
990 
991 	va_start(ap, fmt);
992 	aprint_verbose_internal(ifp->if_xname, fmt, ap);
993 	va_end(ap);
994 }
995 
996 /*
997  * aprint_debug: Send to console and log only if AB_DEBUG.
998  */
999 static void
1000 aprint_debug_internal(const char *prefix, const char *fmt, va_list ap)
1001 {
1002 	if ((boothowto & AB_DEBUG) == 0)
1003 		return;
1004 
1005 	kprintf_lock();
1006 
1007 	if (prefix)
1008 		kprintf_internal("%s: ", TOCONS | TOLOG, NULL, NULL, prefix);
1009 	kprintf(fmt, TOCONS | TOLOG, NULL, NULL, ap);
1010 
1011 	kprintf_unlock();
1012 }
1013 
1014 void
1015 aprint_debug(const char *fmt, ...)
1016 {
1017 	va_list ap;
1018 
1019 	va_start(ap, fmt);
1020 	aprint_debug_internal(NULL, fmt, ap);
1021 	va_end(ap);
1022 }
1023 
1024 void
1025 aprint_debug_dev(device_t dv, const char *fmt, ...)
1026 {
1027 	va_list ap;
1028 
1029 	va_start(ap, fmt);
1030 	aprint_debug_internal(device_xname(dv), fmt, ap);
1031 	va_end(ap);
1032 }
1033 
1034 void
1035 aprint_debug_ifnet(struct ifnet *ifp, const char *fmt, ...)
1036 {
1037 	va_list ap;
1038 
1039 	va_start(ap, fmt);
1040 	aprint_debug_internal(ifp->if_xname, fmt, ap);
1041 	va_end(ap);
1042 }
1043 
1044 void
1045 printf_tolog(const char *fmt, ...)
1046 {
1047 	va_list ap;
1048 
1049 	kprintf_lock();
1050 
1051 	va_start(ap, fmt);
1052 	kprintf(fmt, TOLOG, NULL, NULL, ap);
1053 	va_end(ap);
1054 
1055 	kprintf_unlock();
1056 }
1057 
1058 /*
1059  * printf_nolog: Like printf(), but does not send message to the log.
1060  */
1061 
1062 void
1063 printf_nolog(const char *fmt, ...)
1064 {
1065 	va_list ap;
1066 
1067 	kprintf_lock();
1068 
1069 	va_start(ap, fmt);
1070 	kprintf(fmt, TOCONS, NULL, NULL, ap);
1071 	va_end(ap);
1072 
1073 	kprintf_unlock();
1074 }
1075 
1076 /*
1077  * normal kernel printf functions: printf, vprintf, snprintf, vsnprintf
1078  */
1079 
1080 /*
1081  * printf: print a message to the console and the log
1082  */
1083 void
1084 printf(const char *fmt, ...)
1085 {
1086 	va_list ap;
1087 
1088 	kprintf_lock();
1089 
1090 	va_start(ap, fmt);
1091 	kprintf(fmt, TOCONS | TOLOG, NULL, NULL, ap);
1092 	va_end(ap);
1093 
1094 	kprintf_unlock();
1095 
1096 	if (!panicstr)
1097 		logwakeup();
1098 }
1099 
1100 /*
1101  * vprintf: print a message to the console and the log [already have
1102  *	va_list]
1103  */
1104 
1105 void
1106 vprintf(const char *fmt, va_list ap)
1107 {
1108 	kprintf_lock();
1109 
1110 	kprintf(fmt, TOCONS | TOLOG, NULL, NULL, ap);
1111 
1112 	kprintf_unlock();
1113 
1114 	if (!panicstr)
1115 		logwakeup();
1116 }
1117 
1118 /*
1119  * snprintf: print a message to a buffer
1120  */
1121 int
1122 snprintf(char *bf, size_t size, const char *fmt, ...)
1123 {
1124 	int retval;
1125 	va_list ap;
1126 
1127 	va_start(ap, fmt);
1128 	retval = vsnprintf(bf, size, fmt, ap);
1129 	va_end(ap);
1130 
1131 	return retval;
1132 }
1133 
1134 /*
1135  * vsnprintf: print a message to a buffer [already have va_list]
1136  */
1137 int
1138 vsnprintf(char *bf, size_t size, const char *fmt, va_list ap)
1139 {
1140 	int retval;
1141 	char *p;
1142 
1143 	p = bf + size;
1144 	retval = kprintf(fmt, TOBUFONLY, &p, bf, ap);
1145 	if (bf && size > 0) {
1146 		/* nul terminate */
1147 		if (size <= (size_t)retval)
1148 			bf[size - 1] = '\0';
1149 		else
1150 			bf[retval] = '\0';
1151 	}
1152 	return retval;
1153 }
1154 
1155 /*
1156  * kprintf: scaled down version of printf(3).
1157  *
1158  * this version based on vfprintf() from libc which was derived from
1159  * software contributed to Berkeley by Chris Torek.
1160  *
1161  * NOTE: The kprintf mutex must be held if we're going TOBUF or TOCONS!
1162  */
1163 
1164 /*
1165  * macros for converting digits to letters and vice versa
1166  */
1167 #define	to_digit(c)	((c) - '0')
1168 #define is_digit(c)	((unsigned)to_digit(c) <= 9)
1169 #define	to_char(n)	((n) + '0')
1170 
1171 /*
1172  * flags used during conversion.
1173  */
1174 #define	ALT		0x001		/* alternate form */
1175 #define	HEXPREFIX	0x002		/* add 0x or 0X prefix */
1176 #define	LADJUST		0x004		/* left adjustment */
1177 #define	LONGDBL		0x008		/* long double; unimplemented */
1178 #define	LONGINT		0x010		/* long integer */
1179 #define	QUADINT		0x020		/* quad integer */
1180 #define	SHORTINT	0x040		/* short integer */
1181 #define	MAXINT		0x080		/* intmax_t */
1182 #define	PTRINT		0x100		/* intptr_t */
1183 #define	SIZEINT		0x200		/* size_t */
1184 #define	ZEROPAD		0x400		/* zero (as opposed to blank) pad */
1185 #define FPT		0x800		/* Floating point number */
1186 
1187 	/*
1188 	 * To extend shorts properly, we need both signed and unsigned
1189 	 * argument extraction methods.
1190 	 */
1191 #define	SARG() \
1192 	(flags&MAXINT ? va_arg(ap, intmax_t) : \
1193 	    flags&PTRINT ? va_arg(ap, intptr_t) : \
1194 	    flags&SIZEINT ? va_arg(ap, ssize_t) : /* XXX */ \
1195 	    flags&QUADINT ? va_arg(ap, quad_t) : \
1196 	    flags&LONGINT ? va_arg(ap, long) : \
1197 	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
1198 	    (long)va_arg(ap, int))
1199 #define	UARG() \
1200 	(flags&MAXINT ? va_arg(ap, uintmax_t) : \
1201 	    flags&PTRINT ? va_arg(ap, uintptr_t) : \
1202 	    flags&SIZEINT ? va_arg(ap, size_t) : \
1203 	    flags&QUADINT ? va_arg(ap, u_quad_t) : \
1204 	    flags&LONGINT ? va_arg(ap, u_long) : \
1205 	    flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
1206 	    (u_long)va_arg(ap, u_int))
1207 
1208 #define KPRINTF_PUTCHAR(C) {						\
1209 	if (oflags == TOBUFONLY) {					\
1210 		if (sbuf && ((vp == NULL) || (sbuf < tailp))) 		\
1211 			*sbuf++ = (C);					\
1212 	} else {							\
1213 		putchar((C), oflags, vp);				\
1214 	}								\
1215 }
1216 
1217 void
1218 device_printf(device_t dev, const char *fmt, ...)
1219 {
1220 	va_list ap;
1221 
1222 	va_start(ap, fmt);
1223 	printf("%s: ", device_xname(dev));
1224 	vprintf(fmt, ap);
1225 	va_end(ap);
1226 	return;
1227 }
1228 
1229 /*
1230  * Guts of kernel printf.  Note, we already expect to be in a mutex!
1231  */
1232 int
1233 kprintf(const char *fmt0, int oflags, void *vp, char *sbuf, va_list ap)
1234 {
1235 	const char *fmt;	/* format string */
1236 	int ch;			/* character from fmt */
1237 	int n;			/* handy integer (short term usage) */
1238 	char *cp;		/* handy char pointer (short term usage) */
1239 	int flags;		/* flags as above */
1240 	int ret;		/* return value accumulator */
1241 	int width;		/* width from format (%8d), or 0 */
1242 	int prec;		/* precision from format (%.3d), or -1 */
1243 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
1244 
1245 	u_quad_t _uquad;	/* integer arguments %[diouxX] */
1246 	enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
1247 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
1248 	int realsz;		/* field size expanded by dprec */
1249 	int size;		/* size of converted field or string */
1250 	const char *xdigs;	/* digits for [xX] conversion */
1251 	char bf[KPRINTF_BUFSIZE]; /* space for %c, %[diouxX] */
1252 	char *tailp;		/* tail pointer for snprintf */
1253 
1254 	if (oflags == TOBUFONLY && (vp != NULL))
1255 		tailp = *(char **)vp;
1256 	else
1257 		tailp = NULL;
1258 
1259 	cp = NULL;	/* XXX: shutup gcc */
1260 	size = 0;	/* XXX: shutup gcc */
1261 
1262 	fmt = fmt0;
1263 	ret = 0;
1264 
1265 	xdigs = NULL;		/* XXX: shut up gcc warning */
1266 
1267 	/*
1268 	 * Scan the format for conversions (`%' character).
1269 	 */
1270 	for (;;) {
1271 		for (; *fmt != '%' && *fmt; fmt++) {
1272 			ret++;
1273 			KPRINTF_PUTCHAR(*fmt);
1274 		}
1275 		if (*fmt == 0)
1276 			goto done;
1277 
1278 		fmt++;		/* skip over '%' */
1279 
1280 		flags = 0;
1281 		dprec = 0;
1282 		width = 0;
1283 		prec = -1;
1284 		sign = '\0';
1285 
1286 rflag:		ch = *fmt++;
1287 reswitch:	switch (ch) {
1288 		case ' ':
1289 			/*
1290 			 * ``If the space and + flags both appear, the space
1291 			 * flag will be ignored.''
1292 			 *	-- ANSI X3J11
1293 			 */
1294 			if (!sign)
1295 				sign = ' ';
1296 			goto rflag;
1297 		case '#':
1298 			flags |= ALT;
1299 			goto rflag;
1300 		case '*':
1301 			/*
1302 			 * ``A negative field width argument is taken as a
1303 			 * - flag followed by a positive field width.''
1304 			 *	-- ANSI X3J11
1305 			 * They don't exclude field widths read from args.
1306 			 */
1307 			if ((width = va_arg(ap, int)) >= 0)
1308 				goto rflag;
1309 			width = -width;
1310 			/* FALLTHROUGH */
1311 		case '-':
1312 			flags |= LADJUST;
1313 			goto rflag;
1314 		case '+':
1315 			sign = '+';
1316 			goto rflag;
1317 		case '.':
1318 			if ((ch = *fmt++) == '*') {
1319 				n = va_arg(ap, int);
1320 				prec = n < 0 ? -1 : n;
1321 				goto rflag;
1322 			}
1323 			n = 0;
1324 			while (is_digit(ch)) {
1325 				n = 10 * n + to_digit(ch);
1326 				ch = *fmt++;
1327 			}
1328 			prec = n < 0 ? -1 : n;
1329 			goto reswitch;
1330 		case '0':
1331 			/*
1332 			 * ``Note that 0 is taken as a flag, not as the
1333 			 * beginning of a field width.''
1334 			 *	-- ANSI X3J11
1335 			 */
1336 			flags |= ZEROPAD;
1337 			goto rflag;
1338 		case '1': case '2': case '3': case '4':
1339 		case '5': case '6': case '7': case '8': case '9':
1340 			n = 0;
1341 			do {
1342 				n = 10 * n + to_digit(ch);
1343 				ch = *fmt++;
1344 			} while (is_digit(ch));
1345 			width = n;
1346 			goto reswitch;
1347 		case 'h':
1348 			flags |= SHORTINT;
1349 			goto rflag;
1350 		case 'j':
1351 			flags |= MAXINT;
1352 			goto rflag;
1353 		case 'l':
1354 			if (*fmt == 'l') {
1355 				fmt++;
1356 				flags |= QUADINT;
1357 			} else {
1358 				flags |= LONGINT;
1359 			}
1360 			goto rflag;
1361 		case 'q':
1362 			flags |= QUADINT;
1363 			goto rflag;
1364 		case 't':
1365 			flags |= PTRINT;
1366 			goto rflag;
1367 		case 'z':
1368 			flags |= SIZEINT;
1369 			goto rflag;
1370 		case 'c':
1371 			*(cp = bf) = va_arg(ap, int);
1372 			size = 1;
1373 			sign = '\0';
1374 			break;
1375 		case 'D':
1376 			flags |= LONGINT;
1377 			/*FALLTHROUGH*/
1378 		case 'd':
1379 		case 'i':
1380 			_uquad = SARG();
1381 			if ((quad_t)_uquad < 0) {
1382 				_uquad = -_uquad;
1383 				sign = '-';
1384 			}
1385 			base = DEC;
1386 			goto number;
1387 		case 'n':
1388 			if (flags & MAXINT)
1389 				*va_arg(ap, intmax_t *) = ret;
1390 			else if (flags & PTRINT)
1391 				*va_arg(ap, intptr_t *) = ret;
1392 			else if (flags & SIZEINT)
1393 				*va_arg(ap, ssize_t *) = ret;
1394 			else if (flags & QUADINT)
1395 				*va_arg(ap, quad_t *) = ret;
1396 			else if (flags & LONGINT)
1397 				*va_arg(ap, long *) = ret;
1398 			else if (flags & SHORTINT)
1399 				*va_arg(ap, short *) = ret;
1400 			else
1401 				*va_arg(ap, int *) = ret;
1402 			continue;	/* no output */
1403 		case 'O':
1404 			flags |= LONGINT;
1405 			/*FALLTHROUGH*/
1406 		case 'o':
1407 			_uquad = UARG();
1408 			base = OCT;
1409 			goto nosign;
1410 		case 'p':
1411 			/*
1412 			 * ``The argument shall be a pointer to void.  The
1413 			 * value of the pointer is converted to a sequence
1414 			 * of printable characters, in an implementation-
1415 			 * defined manner.''
1416 			 *	-- ANSI X3J11
1417 			 */
1418 			/* NOSTRICT */
1419 			_uquad = (u_long)va_arg(ap, void *);
1420 			base = HEX;
1421 			xdigs = hexdigits;
1422 			flags |= HEXPREFIX;
1423 			ch = 'x';
1424 			goto nosign;
1425 		case 's':
1426 			if ((cp = va_arg(ap, char *)) == NULL)
1427 				/*XXXUNCONST*/
1428 				cp = __UNCONST("(null)");
1429 			if (prec >= 0) {
1430 				/*
1431 				 * can't use strlen; can only look for the
1432 				 * NUL in the first `prec' characters, and
1433 				 * strlen() will go further.
1434 				 */
1435 				char *p = memchr(cp, 0, prec);
1436 
1437 				if (p != NULL) {
1438 					size = p - cp;
1439 					if (size > prec)
1440 						size = prec;
1441 				} else
1442 					size = prec;
1443 			} else
1444 				size = strlen(cp);
1445 			sign = '\0';
1446 			break;
1447 		case 'U':
1448 			flags |= LONGINT;
1449 			/*FALLTHROUGH*/
1450 		case 'u':
1451 			_uquad = UARG();
1452 			base = DEC;
1453 			goto nosign;
1454 		case 'X':
1455 			xdigs = HEXDIGITS;
1456 			goto hex;
1457 		case 'x':
1458 			xdigs = hexdigits;
1459 hex:			_uquad = UARG();
1460 			base = HEX;
1461 			/* leading 0x/X only if non-zero */
1462 			if (flags & ALT && _uquad != 0)
1463 				flags |= HEXPREFIX;
1464 
1465 			/* unsigned conversions */
1466 nosign:			sign = '\0';
1467 			/*
1468 			 * ``... diouXx conversions ... if a precision is
1469 			 * specified, the 0 flag will be ignored.''
1470 			 *	-- ANSI X3J11
1471 			 */
1472 number:			if ((dprec = prec) >= 0)
1473 				flags &= ~ZEROPAD;
1474 
1475 			/*
1476 			 * ``The result of converting a zero value with an
1477 			 * explicit precision of zero is no characters.''
1478 			 *	-- ANSI X3J11
1479 			 */
1480 			cp = bf + KPRINTF_BUFSIZE;
1481 			if (_uquad != 0 || prec != 0) {
1482 				/*
1483 				 * Unsigned mod is hard, and unsigned mod
1484 				 * by a constant is easier than that by
1485 				 * a variable; hence this switch.
1486 				 */
1487 				switch (base) {
1488 				case OCT:
1489 					do {
1490 						*--cp = to_char(_uquad & 7);
1491 						_uquad >>= 3;
1492 					} while (_uquad);
1493 					/* handle octal leading 0 */
1494 					if (flags & ALT && *cp != '0')
1495 						*--cp = '0';
1496 					break;
1497 
1498 				case DEC:
1499 					/* many numbers are 1 digit */
1500 					while (_uquad >= 10) {
1501 						*--cp = to_char(_uquad % 10);
1502 						_uquad /= 10;
1503 					}
1504 					*--cp = to_char(_uquad);
1505 					break;
1506 
1507 				case HEX:
1508 					do {
1509 						*--cp = xdigs[_uquad & 15];
1510 						_uquad >>= 4;
1511 					} while (_uquad);
1512 					break;
1513 
1514 				default:
1515 					/*XXXUNCONST*/
1516 					cp = __UNCONST("bug in kprintf: bad base");
1517 					size = strlen(cp);
1518 					goto skipsize;
1519 				}
1520 			}
1521 			size = bf + KPRINTF_BUFSIZE - cp;
1522 		skipsize:
1523 			break;
1524 		default:	/* "%?" prints ?, unless ? is NUL */
1525 			if (ch == '\0')
1526 				goto done;
1527 			/* pretend it was %c with argument ch */
1528 			cp = bf;
1529 			*cp = ch;
1530 			size = 1;
1531 			sign = '\0';
1532 			break;
1533 		}
1534 
1535 		/*
1536 		 * All reasonable formats wind up here.  At this point, `cp'
1537 		 * points to a string which (if not flags&LADJUST) should be
1538 		 * padded out to `width' places.  If flags&ZEROPAD, it should
1539 		 * first be prefixed by any sign or other prefix; otherwise,
1540 		 * it should be blank padded before the prefix is emitted.
1541 		 * After any left-hand padding and prefixing, emit zeroes
1542 		 * required by a decimal [diouxX] precision, then print the
1543 		 * string proper, then emit zeroes required by any leftover
1544 		 * floating precision; finally, if LADJUST, pad with blanks.
1545 		 *
1546 		 * Compute actual size, so we know how much to pad.
1547 		 * size excludes decimal prec; realsz includes it.
1548 		 */
1549 		realsz = dprec > size ? dprec : size;
1550 		if (sign)
1551 			realsz++;
1552 		else if (flags & HEXPREFIX)
1553 			realsz+= 2;
1554 
1555 		/* adjust ret */
1556 		ret += width > realsz ? width : realsz;
1557 
1558 		/* right-adjusting blank padding */
1559 		if ((flags & (LADJUST|ZEROPAD)) == 0) {
1560 			n = width - realsz;
1561 			while (n-- > 0)
1562 				KPRINTF_PUTCHAR(' ');
1563 		}
1564 
1565 		/* prefix */
1566 		if (sign) {
1567 			KPRINTF_PUTCHAR(sign);
1568 		} else if (flags & HEXPREFIX) {
1569 			KPRINTF_PUTCHAR('0');
1570 			KPRINTF_PUTCHAR(ch);
1571 		}
1572 
1573 		/* right-adjusting zero padding */
1574 		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD) {
1575 			n = width - realsz;
1576 			while (n-- > 0)
1577 				KPRINTF_PUTCHAR('0');
1578 		}
1579 
1580 		/* leading zeroes from decimal precision */
1581 		n = dprec - size;
1582 		while (n-- > 0)
1583 			KPRINTF_PUTCHAR('0');
1584 
1585 		/* the string or number proper */
1586 		for (; size--; cp++)
1587 			KPRINTF_PUTCHAR(*cp);
1588 		/* left-adjusting padding (always blank) */
1589 		if (flags & LADJUST) {
1590 			n = width - realsz;
1591 			while (n-- > 0)
1592 				KPRINTF_PUTCHAR(' ');
1593 		}
1594 	}
1595 
1596 done:
1597 	if ((oflags == TOBUFONLY) && (vp != NULL))
1598 		*(char **)vp = sbuf;
1599 	(*v_flush)();
1600 
1601 #ifdef RND_PRINTF
1602 	if (!cold) {
1603 		struct timespec ts;
1604 		(void)nanotime(&ts);
1605 		SHA512_Update(&kprnd_sha, (char *)&ts, sizeof(ts));
1606 	}
1607 #endif
1608 	return ret;
1609 }
1610