xref: /netbsd-src/sys/kern/subr_prf.c (revision fc4f42693f9b1c31f39f9cf50af1bf2010325808)
1 /*	$NetBSD: subr_prf.c,v 1.170 2018/04/14 01:53:38 kre 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 1.170 2018/04/14 01:53:38 kre 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 #ifndef KLOG_NOTIMESTAMP
486 static int needtstamp = 1;
487 int log_ts_prec = 7;
488 
489 static void
490 addtstamp(int flags, struct tty *tp)
491 {
492 	char buf[64];
493 	struct timespec ts;
494 	int n, prec;
495 	long fsec;
496 
497 	prec = log_ts_prec;
498 	if (prec < 0) {
499 		prec = 0;
500 		log_ts_prec = prec;
501 	} else if (prec > 9) {
502 		prec = 9;
503 		log_ts_prec = prec;
504 	}
505 
506 	getnanouptime(&ts);
507 
508 	for (n = prec, fsec = ts.tv_nsec; n < 8; n++)
509 		fsec /= 10;
510 	if (n < 9)
511 		fsec = (fsec / 10) + ((fsec % 10) >= 5);
512 
513 	n = snprintf(buf, sizeof(buf), "[% 4jd.%.*ld] ",
514 	    (intmax_t)ts.tv_sec, prec, fsec);
515 
516 	for (int i = 0; i < n; i++)
517 		putone(buf[i], flags, tp);
518 }
519 #endif
520 
521 /*
522  * putchar: print a single character on console or user terminal.
523  *
524  * => if console, then the last MSGBUFS chars are saved in msgbuf
525  *	for inspection later (e.g. dmesg/syslog)
526  * => we must already be in the mutex!
527  */
528 static void
529 putchar(int c, int flags, struct tty *tp)
530 {
531 	if (c & KLOG_PRI) {
532 		putlogpri(c & ~KLOG_PRI);
533 		return;
534 	}
535 
536 #ifndef KLOG_NOTIMESTAMP
537 	if (c != '\0' && c != '\n' && needtstamp) {
538 		addtstamp(flags, tp);
539 		needtstamp = 0;
540 	}
541 
542 	if (c == '\n')
543 		needtstamp = 1;
544 #endif
545 	putone(c, flags, tp);
546 
547 #ifdef DDB
548 	if (flags & TODDB) {
549 		db_putchar(c);
550 		return;
551 	}
552 #endif
553 
554 #ifdef RND_PRINTF
555 	if (__predict_true(kprintf_inited)) {
556 		static uint8_t rbuf[SHA512_BLOCK_LENGTH];
557 		static int cursor;
558 
559 		rbuf[cursor] = c;
560 		if (cursor == sizeof(rbuf) - 1) {
561 			SHA512_Update(&kprnd_sha, rbuf, sizeof(rbuf));
562 			kprnd_added++;
563 			cursor = 0;
564 		} else {
565 			cursor++;
566 		}
567 	}
568 #endif
569 }
570 
571 /*
572  * tablefull: warn that a system table is full
573  */
574 
575 void
576 tablefull(const char *tab, const char *hint)
577 {
578 	if (hint)
579 		log(LOG_ERR, "%s: table is full - %s\n", tab, hint);
580 	else
581 		log(LOG_ERR, "%s: table is full\n", tab);
582 }
583 
584 
585 /*
586  * uprintf: print to the controlling tty of the current process
587  *
588  * => we may block if the tty queue is full
589  * => no message is printed if the queue doesn't clear in a reasonable
590  *	time
591  */
592 
593 void
594 uprintf(const char *fmt, ...)
595 {
596 	struct proc *p = curproc;
597 	va_list ap;
598 
599 	/* mutex_enter(proc_lock); XXXSMP */
600 
601 	if (p->p_lflag & PL_CONTROLT && p->p_session->s_ttyvp) {
602 		/* No mutex needed; going to process TTY. */
603 		va_start(ap, fmt);
604 		kprintf(fmt, TOTTY, p->p_session->s_ttyp, NULL, ap);
605 		va_end(ap);
606 	}
607 
608 	/* mutex_exit(proc_lock); XXXSMP */
609 }
610 
611 void
612 uprintf_locked(const char *fmt, ...)
613 {
614 	struct proc *p = curproc;
615 	va_list ap;
616 
617 	if (p->p_lflag & PL_CONTROLT && p->p_session->s_ttyvp) {
618 		/* No mutex needed; going to process TTY. */
619 		va_start(ap, fmt);
620 		kprintf(fmt, TOTTY, p->p_session->s_ttyp, NULL, ap);
621 		va_end(ap);
622 	}
623 }
624 
625 /*
626  * tprintf functions: used to send messages to a specific process
627  *
628  * usage:
629  *   get a tpr_t handle on a process "p" by using "tprintf_open(p)"
630  *   use the handle when calling "tprintf"
631  *   when done, do a "tprintf_close" to drop the handle
632  */
633 
634 /*
635  * tprintf_open: get a tprintf handle on a process "p"
636  *
637  * => returns NULL if process can't be printed to
638  */
639 
640 tpr_t
641 tprintf_open(struct proc *p)
642 {
643 	tpr_t cookie;
644 
645 	cookie = NULL;
646 
647 	mutex_enter(proc_lock);
648 	if (p->p_lflag & PL_CONTROLT && p->p_session->s_ttyvp) {
649 		proc_sesshold(p->p_session);
650 		cookie = (tpr_t)p->p_session;
651 	}
652 	mutex_exit(proc_lock);
653 
654 	return cookie;
655 }
656 
657 /*
658  * tprintf_close: dispose of a tprintf handle obtained with tprintf_open
659  */
660 
661 void
662 tprintf_close(tpr_t sess)
663 {
664 
665 	if (sess) {
666 		mutex_enter(proc_lock);
667 		/* Releases proc_lock. */
668 		proc_sessrele((struct session *)sess);
669 	}
670 }
671 
672 /*
673  * tprintf: given tprintf handle to a process [obtained with tprintf_open],
674  * send a message to the controlling tty for that process.
675  *
676  * => also sends message to /dev/klog
677  */
678 void
679 tprintf(tpr_t tpr, const char *fmt, ...)
680 {
681 	struct session *sess = (struct session *)tpr;
682 	struct tty *tp = NULL;
683 	int flags = TOLOG;
684 	va_list ap;
685 
686 	/* mutex_enter(proc_lock); XXXSMP */
687 	if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
688 		flags |= TOTTY;
689 		tp = sess->s_ttyp;
690 	}
691 
692 	kprintf_lock();
693 
694 	klogpri(LOG_INFO);
695 	va_start(ap, fmt);
696 	kprintf(fmt, flags, tp, NULL, ap);
697 	va_end(ap);
698 
699 	kprintf_unlock();
700 	/* mutex_exit(proc_lock);	XXXSMP */
701 
702 	logwakeup();
703 }
704 
705 
706 /*
707  * ttyprintf: send a message to a specific tty
708  *
709  * => should be used only by tty driver or anything that knows the
710  *    underlying tty will not be revoked(2)'d away.  [otherwise,
711  *    use tprintf]
712  */
713 void
714 ttyprintf(struct tty *tp, const char *fmt, ...)
715 {
716 	va_list ap;
717 
718 	/* No mutex needed; going to process TTY. */
719 	va_start(ap, fmt);
720 	kprintf(fmt, TOTTY, tp, NULL, ap);
721 	va_end(ap);
722 }
723 
724 #ifdef DDB
725 
726 /*
727  * db_printf: printf for DDB (via db_putchar)
728  */
729 
730 void
731 db_printf(const char *fmt, ...)
732 {
733 	va_list ap;
734 
735 	/* No mutex needed; DDB pauses all processors. */
736 	va_start(ap, fmt);
737 	kprintf(fmt, TODDB, NULL, NULL, ap);
738 	va_end(ap);
739 
740 	if (db_tee_msgbuf) {
741 		va_start(ap, fmt);
742 		kprintf(fmt, TOLOG, NULL, NULL, ap);
743 		va_end(ap);
744 	}
745 }
746 
747 void
748 db_vprintf(const char *fmt, va_list ap)
749 {
750 	va_list cap;
751 
752 	va_copy(cap, ap);
753 	/* No mutex needed; DDB pauses all processors. */
754 	kprintf(fmt, TODDB, NULL, NULL, ap);
755 	if (db_tee_msgbuf)
756 		kprintf(fmt, TOLOG, NULL, NULL, cap);
757 	va_end(cap);
758 }
759 
760 #endif /* DDB */
761 
762 static void
763 kprintf_internal(const char *fmt, int oflags, void *vp, char *sbuf, ...)
764 {
765 	va_list ap;
766 
767 	va_start(ap, sbuf);
768 	(void)kprintf(fmt, oflags, vp, sbuf, ap);
769 	va_end(ap);
770 }
771 
772 /*
773  * Device autoconfiguration printf routines.  These change their
774  * behavior based on the AB_* flags in boothowto.  If AB_SILENT
775  * is set, messages never go to the console (but they still always
776  * go to the log).  AB_VERBOSE overrides AB_SILENT.
777  */
778 
779 /*
780  * aprint_normal: Send to console unless AB_QUIET.  Always goes
781  * to the log.
782  */
783 static void
784 aprint_normal_internal(const char *prefix, const char *fmt, va_list ap)
785 {
786 	int flags = TOLOG;
787 
788 	if ((boothowto & (AB_SILENT|AB_QUIET)) == 0 ||
789 	    (boothowto & AB_VERBOSE) != 0)
790 		flags |= TOCONS;
791 
792 	kprintf_lock();
793 
794 	if (prefix)
795 		kprintf_internal("%s: ", flags, NULL, NULL, prefix);
796 	kprintf(fmt, flags, NULL, NULL, ap);
797 
798 	kprintf_unlock();
799 
800 	if (!panicstr)
801 		logwakeup();
802 }
803 
804 void
805 aprint_normal(const char *fmt, ...)
806 {
807 	va_list ap;
808 
809 	va_start(ap, fmt);
810 	aprint_normal_internal(NULL, fmt, ap);
811 	va_end(ap);
812 }
813 
814 void
815 aprint_normal_dev(device_t dv, const char *fmt, ...)
816 {
817 	va_list ap;
818 
819 	va_start(ap, fmt);
820 	aprint_normal_internal(device_xname(dv), fmt, ap);
821 	va_end(ap);
822 }
823 
824 void
825 aprint_normal_ifnet(struct ifnet *ifp, const char *fmt, ...)
826 {
827 	va_list ap;
828 
829 	va_start(ap, fmt);
830 	aprint_normal_internal(ifp->if_xname, fmt, ap);
831 	va_end(ap);
832 }
833 
834 /*
835  * aprint_error: Send to console unless AB_QUIET.  Always goes
836  * to the log.  Also counts the number of times called so other
837  * parts of the kernel can report the number of errors during a
838  * given phase of system startup.
839  */
840 static int aprint_error_count;
841 
842 int
843 aprint_get_error_count(void)
844 {
845 	int count;
846 
847 	kprintf_lock();
848 
849 	count = aprint_error_count;
850 	aprint_error_count = 0;
851 
852 	kprintf_unlock();
853 
854 	return (count);
855 }
856 
857 static void
858 aprint_error_internal(const char *prefix, const char *fmt, va_list ap)
859 {
860 	int flags = TOLOG;
861 
862 	if ((boothowto & (AB_SILENT|AB_QUIET)) == 0 ||
863 	    (boothowto & AB_VERBOSE) != 0)
864 		flags |= TOCONS;
865 
866 	kprintf_lock();
867 
868 	aprint_error_count++;
869 
870 	if (prefix)
871 		kprintf_internal("%s: ", flags, NULL, NULL, prefix);
872 	kprintf(fmt, flags, NULL, NULL, ap);
873 
874 	kprintf_unlock();
875 
876 	if (!panicstr)
877 		logwakeup();
878 }
879 
880 void
881 aprint_error(const char *fmt, ...)
882 {
883 	va_list ap;
884 
885 	va_start(ap, fmt);
886 	aprint_error_internal(NULL, fmt, ap);
887 	va_end(ap);
888 }
889 
890 void
891 aprint_error_dev(device_t dv, const char *fmt, ...)
892 {
893 	va_list ap;
894 
895 	va_start(ap, fmt);
896 	aprint_error_internal(device_xname(dv), fmt, ap);
897 	va_end(ap);
898 }
899 
900 void
901 aprint_error_ifnet(struct ifnet *ifp, const char *fmt, ...)
902 {
903 	va_list ap;
904 
905 	va_start(ap, fmt);
906 	aprint_error_internal(ifp->if_xname, fmt, ap);
907 	va_end(ap);
908 }
909 
910 /*
911  * aprint_naive: Send to console only if AB_QUIET.  Never goes
912  * to the log.
913  */
914 static void
915 aprint_naive_internal(const char *prefix, const char *fmt, va_list ap)
916 {
917 	if ((boothowto & (AB_QUIET|AB_SILENT|AB_VERBOSE)) != AB_QUIET)
918 		return;
919 
920 	kprintf_lock();
921 
922 	if (prefix)
923 		kprintf_internal("%s: ", TOCONS, NULL, NULL, prefix);
924 	kprintf(fmt, TOCONS, NULL, NULL, ap);
925 
926 	kprintf_unlock();
927 }
928 
929 void
930 aprint_naive(const char *fmt, ...)
931 {
932 	va_list ap;
933 
934 	va_start(ap, fmt);
935 	aprint_naive_internal(NULL, fmt, ap);
936 	va_end(ap);
937 }
938 
939 void
940 aprint_naive_dev(device_t dv, const char *fmt, ...)
941 {
942 	va_list ap;
943 
944 	va_start(ap, fmt);
945 	aprint_naive_internal(device_xname(dv), fmt, ap);
946 	va_end(ap);
947 }
948 
949 void
950 aprint_naive_ifnet(struct ifnet *ifp, const char *fmt, ...)
951 {
952 	va_list ap;
953 
954 	va_start(ap, fmt);
955 	aprint_naive_internal(ifp->if_xname, fmt, ap);
956 	va_end(ap);
957 }
958 
959 /*
960  * aprint_verbose: Send to console only if AB_VERBOSE.  Always
961  * goes to the log.
962  */
963 static void
964 aprint_verbose_internal(const char *prefix, const char *fmt, va_list ap)
965 {
966 	int flags = TOLOG;
967 
968 	if (boothowto & AB_VERBOSE)
969 		flags |= TOCONS;
970 
971 	kprintf_lock();
972 
973 	if (prefix)
974 		kprintf_internal("%s: ", flags, NULL, NULL, prefix);
975 	kprintf(fmt, flags, NULL, NULL, ap);
976 
977 	kprintf_unlock();
978 
979 	if (!panicstr)
980 		logwakeup();
981 }
982 
983 void
984 aprint_verbose(const char *fmt, ...)
985 {
986 	va_list ap;
987 
988 	va_start(ap, fmt);
989 	aprint_verbose_internal(NULL, fmt, ap);
990 	va_end(ap);
991 }
992 
993 void
994 aprint_verbose_dev(device_t dv, const char *fmt, ...)
995 {
996 	va_list ap;
997 
998 	va_start(ap, fmt);
999 	aprint_verbose_internal(device_xname(dv), fmt, ap);
1000 	va_end(ap);
1001 }
1002 
1003 void
1004 aprint_verbose_ifnet(struct ifnet *ifp, const char *fmt, ...)
1005 {
1006 	va_list ap;
1007 
1008 	va_start(ap, fmt);
1009 	aprint_verbose_internal(ifp->if_xname, fmt, ap);
1010 	va_end(ap);
1011 }
1012 
1013 /*
1014  * aprint_debug: Send to console and log only if AB_DEBUG.
1015  */
1016 static void
1017 aprint_debug_internal(const char *prefix, const char *fmt, va_list ap)
1018 {
1019 	if ((boothowto & AB_DEBUG) == 0)
1020 		return;
1021 
1022 	kprintf_lock();
1023 
1024 	if (prefix)
1025 		kprintf_internal("%s: ", TOCONS | TOLOG, NULL, NULL, prefix);
1026 	kprintf(fmt, TOCONS | TOLOG, NULL, NULL, ap);
1027 
1028 	kprintf_unlock();
1029 }
1030 
1031 void
1032 aprint_debug(const char *fmt, ...)
1033 {
1034 	va_list ap;
1035 
1036 	va_start(ap, fmt);
1037 	aprint_debug_internal(NULL, fmt, ap);
1038 	va_end(ap);
1039 }
1040 
1041 void
1042 aprint_debug_dev(device_t dv, const char *fmt, ...)
1043 {
1044 	va_list ap;
1045 
1046 	va_start(ap, fmt);
1047 	aprint_debug_internal(device_xname(dv), fmt, ap);
1048 	va_end(ap);
1049 }
1050 
1051 void
1052 aprint_debug_ifnet(struct ifnet *ifp, const char *fmt, ...)
1053 {
1054 	va_list ap;
1055 
1056 	va_start(ap, fmt);
1057 	aprint_debug_internal(ifp->if_xname, fmt, ap);
1058 	va_end(ap);
1059 }
1060 
1061 void
1062 printf_tolog(const char *fmt, ...)
1063 {
1064 	va_list ap;
1065 
1066 	kprintf_lock();
1067 
1068 	va_start(ap, fmt);
1069 	kprintf(fmt, TOLOG, NULL, NULL, ap);
1070 	va_end(ap);
1071 
1072 	kprintf_unlock();
1073 }
1074 
1075 /*
1076  * printf_nolog: Like printf(), but does not send message to the log.
1077  */
1078 
1079 void
1080 printf_nolog(const char *fmt, ...)
1081 {
1082 	va_list ap;
1083 
1084 	kprintf_lock();
1085 
1086 	va_start(ap, fmt);
1087 	kprintf(fmt, TOCONS, NULL, NULL, ap);
1088 	va_end(ap);
1089 
1090 	kprintf_unlock();
1091 }
1092 
1093 /*
1094  * normal kernel printf functions: printf, vprintf, snprintf, vsnprintf
1095  */
1096 
1097 /*
1098  * printf: print a message to the console and the log
1099  */
1100 void
1101 printf(const char *fmt, ...)
1102 {
1103 	va_list ap;
1104 
1105 	kprintf_lock();
1106 
1107 	va_start(ap, fmt);
1108 	kprintf(fmt, TOCONS | TOLOG, NULL, NULL, ap);
1109 	va_end(ap);
1110 
1111 	kprintf_unlock();
1112 
1113 	if (!panicstr)
1114 		logwakeup();
1115 }
1116 
1117 /*
1118  * vprintf: print a message to the console and the log [already have
1119  *	va_list]
1120  */
1121 
1122 void
1123 vprintf(const char *fmt, va_list ap)
1124 {
1125 	kprintf_lock();
1126 
1127 	kprintf(fmt, TOCONS | TOLOG, NULL, NULL, ap);
1128 
1129 	kprintf_unlock();
1130 
1131 	if (!panicstr)
1132 		logwakeup();
1133 }
1134 
1135 /*
1136  * snprintf: print a message to a buffer
1137  */
1138 int
1139 snprintf(char *bf, size_t size, const char *fmt, ...)
1140 {
1141 	int retval;
1142 	va_list ap;
1143 
1144 	va_start(ap, fmt);
1145 	retval = vsnprintf(bf, size, fmt, ap);
1146 	va_end(ap);
1147 
1148 	return retval;
1149 }
1150 
1151 /*
1152  * vsnprintf: print a message to a buffer [already have va_list]
1153  */
1154 int
1155 vsnprintf(char *bf, size_t size, const char *fmt, va_list ap)
1156 {
1157 	int retval;
1158 	char *p;
1159 
1160 	p = bf + size;
1161 	retval = kprintf(fmt, TOBUFONLY, &p, bf, ap);
1162 	if (bf && size > 0) {
1163 		/* nul terminate */
1164 		if (size <= (size_t)retval)
1165 			bf[size - 1] = '\0';
1166 		else
1167 			bf[retval] = '\0';
1168 	}
1169 	return retval;
1170 }
1171 
1172 /*
1173  * kprintf: scaled down version of printf(3).
1174  *
1175  * this version based on vfprintf() from libc which was derived from
1176  * software contributed to Berkeley by Chris Torek.
1177  *
1178  * NOTE: The kprintf mutex must be held if we're going TOBUF or TOCONS!
1179  */
1180 
1181 /*
1182  * macros for converting digits to letters and vice versa
1183  */
1184 #define	to_digit(c)	((c) - '0')
1185 #define is_digit(c)	((unsigned)to_digit(c) <= 9)
1186 #define	to_char(n)	((n) + '0')
1187 
1188 /*
1189  * flags used during conversion.
1190  */
1191 #define	ALT		0x001		/* alternate form */
1192 #define	HEXPREFIX	0x002		/* add 0x or 0X prefix */
1193 #define	LADJUST		0x004		/* left adjustment */
1194 #define	LONGDBL		0x008		/* long double; unimplemented */
1195 #define	LONGINT		0x010		/* long integer */
1196 #define	QUADINT		0x020		/* quad integer */
1197 #define	SHORTINT	0x040		/* short integer */
1198 #define	MAXINT		0x080		/* intmax_t */
1199 #define	PTRINT		0x100		/* intptr_t */
1200 #define	SIZEINT		0x200		/* size_t */
1201 #define	ZEROPAD		0x400		/* zero (as opposed to blank) pad */
1202 #define FPT		0x800		/* Floating point number */
1203 
1204 	/*
1205 	 * To extend shorts properly, we need both signed and unsigned
1206 	 * argument extraction methods.
1207 	 */
1208 #define	SARG() \
1209 	(flags&MAXINT ? va_arg(ap, intmax_t) : \
1210 	    flags&PTRINT ? va_arg(ap, intptr_t) : \
1211 	    flags&SIZEINT ? va_arg(ap, ssize_t) : /* XXX */ \
1212 	    flags&QUADINT ? va_arg(ap, quad_t) : \
1213 	    flags&LONGINT ? va_arg(ap, long) : \
1214 	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
1215 	    (long)va_arg(ap, int))
1216 #define	UARG() \
1217 	(flags&MAXINT ? va_arg(ap, uintmax_t) : \
1218 	    flags&PTRINT ? va_arg(ap, uintptr_t) : \
1219 	    flags&SIZEINT ? va_arg(ap, size_t) : \
1220 	    flags&QUADINT ? va_arg(ap, u_quad_t) : \
1221 	    flags&LONGINT ? va_arg(ap, u_long) : \
1222 	    flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
1223 	    (u_long)va_arg(ap, u_int))
1224 
1225 #define KPRINTF_PUTCHAR(C) {						\
1226 	if (oflags == TOBUFONLY) {					\
1227 		if (sbuf && ((vp == NULL) || (sbuf < tailp))) 		\
1228 			*sbuf++ = (C);					\
1229 	} else {							\
1230 		putchar((C), oflags, vp);				\
1231 	}								\
1232 }
1233 
1234 void
1235 device_printf(device_t dev, const char *fmt, ...)
1236 {
1237 	va_list ap;
1238 
1239 	va_start(ap, fmt);
1240 	printf("%s: ", device_xname(dev));
1241 	vprintf(fmt, ap);
1242 	va_end(ap);
1243 	return;
1244 }
1245 
1246 /*
1247  * Guts of kernel printf.  Note, we already expect to be in a mutex!
1248  */
1249 int
1250 kprintf(const char *fmt0, int oflags, void *vp, char *sbuf, va_list ap)
1251 {
1252 	const char *fmt;	/* format string */
1253 	int ch;			/* character from fmt */
1254 	int n;			/* handy integer (short term usage) */
1255 	char *cp;		/* handy char pointer (short term usage) */
1256 	int flags;		/* flags as above */
1257 	int ret;		/* return value accumulator */
1258 	int width;		/* width from format (%8d), or 0 */
1259 	int prec;		/* precision from format (%.3d), or -1 */
1260 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
1261 
1262 	u_quad_t _uquad;	/* integer arguments %[diouxX] */
1263 	enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
1264 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
1265 	int realsz;		/* field size expanded by dprec */
1266 	int size;		/* size of converted field or string */
1267 	const char *xdigs;	/* digits for [xX] conversion */
1268 	char bf[KPRINTF_BUFSIZE]; /* space for %c, %[diouxX] */
1269 	char *tailp;		/* tail pointer for snprintf */
1270 
1271 	if (oflags == TOBUFONLY && (vp != NULL))
1272 		tailp = *(char **)vp;
1273 	else
1274 		tailp = NULL;
1275 
1276 	cp = NULL;	/* XXX: shutup gcc */
1277 	size = 0;	/* XXX: shutup gcc */
1278 
1279 	fmt = fmt0;
1280 	ret = 0;
1281 
1282 	xdigs = NULL;		/* XXX: shut up gcc warning */
1283 
1284 	/*
1285 	 * Scan the format for conversions (`%' character).
1286 	 */
1287 	for (;;) {
1288 		for (; *fmt != '%' && *fmt; fmt++) {
1289 			ret++;
1290 			KPRINTF_PUTCHAR(*fmt);
1291 		}
1292 		if (*fmt == 0)
1293 			goto done;
1294 
1295 		fmt++;		/* skip over '%' */
1296 
1297 		flags = 0;
1298 		dprec = 0;
1299 		width = 0;
1300 		prec = -1;
1301 		sign = '\0';
1302 
1303 rflag:		ch = *fmt++;
1304 reswitch:	switch (ch) {
1305 		case ' ':
1306 			/*
1307 			 * ``If the space and + flags both appear, the space
1308 			 * flag will be ignored.''
1309 			 *	-- ANSI X3J11
1310 			 */
1311 			if (!sign)
1312 				sign = ' ';
1313 			goto rflag;
1314 		case '#':
1315 			flags |= ALT;
1316 			goto rflag;
1317 		case '*':
1318 			/*
1319 			 * ``A negative field width argument is taken as a
1320 			 * - flag followed by a positive field width.''
1321 			 *	-- ANSI X3J11
1322 			 * They don't exclude field widths read from args.
1323 			 */
1324 			if ((width = va_arg(ap, int)) >= 0)
1325 				goto rflag;
1326 			width = -width;
1327 			/* FALLTHROUGH */
1328 		case '-':
1329 			flags |= LADJUST;
1330 			goto rflag;
1331 		case '+':
1332 			sign = '+';
1333 			goto rflag;
1334 		case '.':
1335 			if ((ch = *fmt++) == '*') {
1336 				n = va_arg(ap, int);
1337 				prec = n < 0 ? -1 : n;
1338 				goto rflag;
1339 			}
1340 			n = 0;
1341 			while (is_digit(ch)) {
1342 				n = 10 * n + to_digit(ch);
1343 				ch = *fmt++;
1344 			}
1345 			prec = n < 0 ? -1 : n;
1346 			goto reswitch;
1347 		case '0':
1348 			/*
1349 			 * ``Note that 0 is taken as a flag, not as the
1350 			 * beginning of a field width.''
1351 			 *	-- ANSI X3J11
1352 			 */
1353 			flags |= ZEROPAD;
1354 			goto rflag;
1355 		case '1': case '2': case '3': case '4':
1356 		case '5': case '6': case '7': case '8': case '9':
1357 			n = 0;
1358 			do {
1359 				n = 10 * n + to_digit(ch);
1360 				ch = *fmt++;
1361 			} while (is_digit(ch));
1362 			width = n;
1363 			goto reswitch;
1364 		case 'h':
1365 			flags |= SHORTINT;
1366 			goto rflag;
1367 		case 'j':
1368 			flags |= MAXINT;
1369 			goto rflag;
1370 		case 'l':
1371 			if (*fmt == 'l') {
1372 				fmt++;
1373 				flags |= QUADINT;
1374 			} else {
1375 				flags |= LONGINT;
1376 			}
1377 			goto rflag;
1378 		case 'q':
1379 			flags |= QUADINT;
1380 			goto rflag;
1381 		case 't':
1382 			flags |= PTRINT;
1383 			goto rflag;
1384 		case 'z':
1385 			flags |= SIZEINT;
1386 			goto rflag;
1387 		case 'c':
1388 			*(cp = bf) = va_arg(ap, int);
1389 			size = 1;
1390 			sign = '\0';
1391 			break;
1392 		case 'D':
1393 			flags |= LONGINT;
1394 			/*FALLTHROUGH*/
1395 		case 'd':
1396 		case 'i':
1397 			_uquad = SARG();
1398 			if ((quad_t)_uquad < 0) {
1399 				_uquad = -_uquad;
1400 				sign = '-';
1401 			}
1402 			base = DEC;
1403 			goto number;
1404 		case 'n':
1405 			if (flags & MAXINT)
1406 				*va_arg(ap, intmax_t *) = ret;
1407 			else if (flags & PTRINT)
1408 				*va_arg(ap, intptr_t *) = ret;
1409 			else if (flags & SIZEINT)
1410 				*va_arg(ap, ssize_t *) = ret;
1411 			else if (flags & QUADINT)
1412 				*va_arg(ap, quad_t *) = ret;
1413 			else if (flags & LONGINT)
1414 				*va_arg(ap, long *) = ret;
1415 			else if (flags & SHORTINT)
1416 				*va_arg(ap, short *) = ret;
1417 			else
1418 				*va_arg(ap, int *) = ret;
1419 			continue;	/* no output */
1420 		case 'O':
1421 			flags |= LONGINT;
1422 			/*FALLTHROUGH*/
1423 		case 'o':
1424 			_uquad = UARG();
1425 			base = OCT;
1426 			goto nosign;
1427 		case 'p':
1428 			/*
1429 			 * ``The argument shall be a pointer to void.  The
1430 			 * value of the pointer is converted to a sequence
1431 			 * of printable characters, in an implementation-
1432 			 * defined manner.''
1433 			 *	-- ANSI X3J11
1434 			 */
1435 			/* NOSTRICT */
1436 			_uquad = (u_long)va_arg(ap, void *);
1437 			base = HEX;
1438 			xdigs = hexdigits;
1439 			flags |= HEXPREFIX;
1440 			ch = 'x';
1441 			goto nosign;
1442 		case 's':
1443 			if ((cp = va_arg(ap, char *)) == NULL)
1444 				/*XXXUNCONST*/
1445 				cp = __UNCONST("(null)");
1446 			if (prec >= 0) {
1447 				/*
1448 				 * can't use strlen; can only look for the
1449 				 * NUL in the first `prec' characters, and
1450 				 * strlen() will go further.
1451 				 */
1452 				char *p = memchr(cp, 0, prec);
1453 
1454 				if (p != NULL) {
1455 					size = p - cp;
1456 					if (size > prec)
1457 						size = prec;
1458 				} else
1459 					size = prec;
1460 			} else
1461 				size = strlen(cp);
1462 			sign = '\0';
1463 			break;
1464 		case 'U':
1465 			flags |= LONGINT;
1466 			/*FALLTHROUGH*/
1467 		case 'u':
1468 			_uquad = UARG();
1469 			base = DEC;
1470 			goto nosign;
1471 		case 'X':
1472 			xdigs = HEXDIGITS;
1473 			goto hex;
1474 		case 'x':
1475 			xdigs = hexdigits;
1476 hex:			_uquad = UARG();
1477 			base = HEX;
1478 			/* leading 0x/X only if non-zero */
1479 			if (flags & ALT && _uquad != 0)
1480 				flags |= HEXPREFIX;
1481 
1482 			/* unsigned conversions */
1483 nosign:			sign = '\0';
1484 			/*
1485 			 * ``... diouXx conversions ... if a precision is
1486 			 * specified, the 0 flag will be ignored.''
1487 			 *	-- ANSI X3J11
1488 			 */
1489 number:			if ((dprec = prec) >= 0)
1490 				flags &= ~ZEROPAD;
1491 
1492 			/*
1493 			 * ``The result of converting a zero value with an
1494 			 * explicit precision of zero is no characters.''
1495 			 *	-- ANSI X3J11
1496 			 */
1497 			cp = bf + KPRINTF_BUFSIZE;
1498 			if (_uquad != 0 || prec != 0) {
1499 				/*
1500 				 * Unsigned mod is hard, and unsigned mod
1501 				 * by a constant is easier than that by
1502 				 * a variable; hence this switch.
1503 				 */
1504 				switch (base) {
1505 				case OCT:
1506 					do {
1507 						*--cp = to_char(_uquad & 7);
1508 						_uquad >>= 3;
1509 					} while (_uquad);
1510 					/* handle octal leading 0 */
1511 					if (flags & ALT && *cp != '0')
1512 						*--cp = '0';
1513 					break;
1514 
1515 				case DEC:
1516 					/* many numbers are 1 digit */
1517 					while (_uquad >= 10) {
1518 						*--cp = to_char(_uquad % 10);
1519 						_uquad /= 10;
1520 					}
1521 					*--cp = to_char(_uquad);
1522 					break;
1523 
1524 				case HEX:
1525 					do {
1526 						*--cp = xdigs[_uquad & 15];
1527 						_uquad >>= 4;
1528 					} while (_uquad);
1529 					break;
1530 
1531 				default:
1532 					/*XXXUNCONST*/
1533 					cp = __UNCONST("bug in kprintf: bad base");
1534 					size = strlen(cp);
1535 					goto skipsize;
1536 				}
1537 			}
1538 			size = bf + KPRINTF_BUFSIZE - cp;
1539 		skipsize:
1540 			break;
1541 		default:	/* "%?" prints ?, unless ? is NUL */
1542 			if (ch == '\0')
1543 				goto done;
1544 			/* pretend it was %c with argument ch */
1545 			cp = bf;
1546 			*cp = ch;
1547 			size = 1;
1548 			sign = '\0';
1549 			break;
1550 		}
1551 
1552 		/*
1553 		 * All reasonable formats wind up here.  At this point, `cp'
1554 		 * points to a string which (if not flags&LADJUST) should be
1555 		 * padded out to `width' places.  If flags&ZEROPAD, it should
1556 		 * first be prefixed by any sign or other prefix; otherwise,
1557 		 * it should be blank padded before the prefix is emitted.
1558 		 * After any left-hand padding and prefixing, emit zeroes
1559 		 * required by a decimal [diouxX] precision, then print the
1560 		 * string proper, then emit zeroes required by any leftover
1561 		 * floating precision; finally, if LADJUST, pad with blanks.
1562 		 *
1563 		 * Compute actual size, so we know how much to pad.
1564 		 * size excludes decimal prec; realsz includes it.
1565 		 */
1566 		realsz = dprec > size ? dprec : size;
1567 		if (sign)
1568 			realsz++;
1569 		else if (flags & HEXPREFIX)
1570 			realsz+= 2;
1571 
1572 		/* adjust ret */
1573 		ret += width > realsz ? width : realsz;
1574 
1575 		/* right-adjusting blank padding */
1576 		if ((flags & (LADJUST|ZEROPAD)) == 0) {
1577 			n = width - realsz;
1578 			while (n-- > 0)
1579 				KPRINTF_PUTCHAR(' ');
1580 		}
1581 
1582 		/* prefix */
1583 		if (sign) {
1584 			KPRINTF_PUTCHAR(sign);
1585 		} else if (flags & HEXPREFIX) {
1586 			KPRINTF_PUTCHAR('0');
1587 			KPRINTF_PUTCHAR(ch);
1588 		}
1589 
1590 		/* right-adjusting zero padding */
1591 		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD) {
1592 			n = width - realsz;
1593 			while (n-- > 0)
1594 				KPRINTF_PUTCHAR('0');
1595 		}
1596 
1597 		/* leading zeroes from decimal precision */
1598 		n = dprec - size;
1599 		while (n-- > 0)
1600 			KPRINTF_PUTCHAR('0');
1601 
1602 		/* the string or number proper */
1603 		for (; size--; cp++)
1604 			KPRINTF_PUTCHAR(*cp);
1605 		/* left-adjusting padding (always blank) */
1606 		if (flags & LADJUST) {
1607 			n = width - realsz;
1608 			while (n-- > 0)
1609 				KPRINTF_PUTCHAR(' ');
1610 		}
1611 	}
1612 
1613 done:
1614 	if ((oflags == TOBUFONLY) && (vp != NULL))
1615 		*(char **)vp = sbuf;
1616 	(*v_flush)();
1617 
1618 #ifdef RND_PRINTF
1619 	if (!cold) {
1620 		struct timespec ts;
1621 		(void)nanotime(&ts);
1622 		SHA512_Update(&kprnd_sha, (char *)&ts, sizeof(ts));
1623 	}
1624 #endif
1625 	return ret;
1626 }
1627