xref: /freebsd/sys/kern/subr_prf.c (revision 2357939bc239bd5334a169b62313806178dd8f30)
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  * 4. 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  *	@(#)subr_prf.c	8.3 (Berkeley) 1/21/94
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "opt_ddb.h"
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/lock.h>
45 #include <sys/mutex.h>
46 #include <sys/sx.h>
47 #include <sys/kernel.h>
48 #include <sys/msgbuf.h>
49 #include <sys/malloc.h>
50 #include <sys/proc.h>
51 #include <sys/stddef.h>
52 #include <sys/sysctl.h>
53 #include <sys/tty.h>
54 #include <sys/syslog.h>
55 #include <sys/cons.h>
56 #include <sys/uio.h>
57 
58 #ifdef DDB
59 #include <ddb/ddb.h>
60 #endif
61 
62 /*
63  * Note that stdarg.h and the ANSI style va_start macro is used for both
64  * ANSI and traditional C compilers.
65  */
66 #include <machine/stdarg.h>
67 
68 #define TOCONS	0x01
69 #define TOTTY	0x02
70 #define TOLOG	0x04
71 
72 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
73 #define MAXNBUF	(sizeof(intmax_t) * NBBY + 1)
74 
75 struct putchar_arg {
76 	int	flags;
77 	int	pri;
78 	struct	tty *tty;
79 };
80 
81 struct snprintf_arg {
82 	char	*str;
83 	size_t	remain;
84 };
85 
86 extern	int log_open;
87 
88 static void  msglogchar(int c, int pri);
89 static void  putchar(int ch, void *arg);
90 static char *ksprintn(char *nbuf, uintmax_t num, int base, int *len);
91 static void  snprintf_func(int ch, void *arg);
92 
93 static int consintr = 1;		/* Ok to handle console interrupts? */
94 static int msgbufmapped;		/* Set when safe to use msgbuf */
95 int msgbuftrigger;
96 
97 static int      log_console_output = 1;
98 TUNABLE_INT("kern.log_console_output", &log_console_output);
99 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
100     &log_console_output, 0, "");
101 
102 /*
103  * Warn that a system table is full.
104  */
105 void
106 tablefull(const char *tab)
107 {
108 
109 	log(LOG_ERR, "%s: table is full\n", tab);
110 }
111 
112 /*
113  * Uprintf prints to the controlling terminal for the current process.
114  * It may block if the tty queue is overfull.  No message is printed if
115  * the queue does not clear in a reasonable time.
116  */
117 int
118 uprintf(const char *fmt, ...)
119 {
120 	struct thread *td = curthread;
121 	struct proc *p = td->td_proc;
122 	va_list ap;
123 	struct putchar_arg pca;
124 	int retval;
125 
126 	if (td == NULL || td == PCPU_GET(idlethread))
127 		return (0);
128 
129 	p = td->td_proc;
130 	PROC_LOCK(p);
131 	if ((p->p_flag & P_CONTROLT) == 0) {
132 		PROC_UNLOCK(p);
133 		return (0);
134 	}
135 	SESS_LOCK(p->p_session);
136 	pca.tty = p->p_session->s_ttyp;
137 	SESS_UNLOCK(p->p_session);
138 	PROC_UNLOCK(p);
139 	if (pca.tty == NULL)
140 		return (0);
141 	pca.flags = TOTTY;
142 	va_start(ap, fmt);
143 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
144 	va_end(ap);
145 
146 	return (retval);
147 }
148 
149 /*
150  * tprintf prints on the controlling terminal associated
151  * with the given session, possibly to the log as well.
152  */
153 void
154 tprintf(struct proc *p, int pri, const char *fmt, ...)
155 {
156 	struct tty *tp = NULL;
157 	int flags = 0;
158 	va_list ap;
159 	struct putchar_arg pca;
160 	struct session *sess = NULL;
161 
162 	if (pri != -1)
163 		flags |= TOLOG;
164 	if (p != NULL) {
165 		PROC_LOCK(p);
166 		if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
167 			sess = p->p_session;
168 			SESS_LOCK(sess);
169 			PROC_UNLOCK(p);
170 			SESSHOLD(sess);
171 			tp = sess->s_ttyp;
172 			SESS_UNLOCK(sess);
173 			if (ttycheckoutq(tp, 0))
174 				flags |= TOTTY;
175 			else
176 				tp = NULL;
177 		} else
178 			PROC_UNLOCK(p);
179 	}
180 	pca.pri = pri;
181 	pca.tty = tp;
182 	pca.flags = flags;
183 	va_start(ap, fmt);
184 	kvprintf(fmt, putchar, &pca, 10, ap);
185 	va_end(ap);
186 	if (sess != NULL) {
187 		SESS_LOCK(sess);
188 		SESSRELE(sess);
189 		SESS_UNLOCK(sess);
190 	}
191 	msgbuftrigger = 1;
192 }
193 
194 /*
195  * Ttyprintf displays a message on a tty; it should be used only by
196  * the tty driver, or anything that knows the underlying tty will not
197  * be revoke(2)'d away.  Other callers should use tprintf.
198  */
199 int
200 ttyprintf(struct tty *tp, const char *fmt, ...)
201 {
202 	va_list ap;
203 	struct putchar_arg pca;
204 	int retval;
205 
206 	va_start(ap, fmt);
207 	pca.tty = tp;
208 	pca.flags = TOTTY;
209 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
210 	va_end(ap);
211 	return (retval);
212 }
213 
214 /*
215  * Log writes to the log buffer, and guarantees not to sleep (so can be
216  * called by interrupt routines).  If there is no process reading the
217  * log yet, it writes to the console also.
218  */
219 void
220 log(int level, const char *fmt, ...)
221 {
222 	va_list ap;
223 	struct putchar_arg pca;
224 
225 	pca.tty = NULL;
226 	pca.pri = level;
227 	pca.flags = log_open ? TOLOG : TOCONS;
228 
229 	va_start(ap, fmt);
230 	kvprintf(fmt, putchar, &pca, 10, ap);
231 	va_end(ap);
232 
233 	msgbuftrigger = 1;
234 }
235 
236 #define CONSCHUNK 128
237 
238 void
239 log_console(struct uio *uio)
240 {
241 	int c, i, error, iovlen, nl;
242 	struct uio muio;
243 	struct iovec *miov = NULL;
244 	char *consbuffer;
245 	int pri;
246 
247 	if (!log_console_output)
248 		return;
249 
250 	pri = LOG_INFO | LOG_CONSOLE;
251 	muio = *uio;
252 	iovlen = uio->uio_iovcnt * sizeof (struct iovec);
253 	MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
254 	MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
255 	bcopy(muio.uio_iov, miov, iovlen);
256 	muio.uio_iov = miov;
257 	uio = &muio;
258 
259 	nl = 0;
260 	while (uio->uio_resid > 0) {
261 		c = imin(uio->uio_resid, CONSCHUNK);
262 		error = uiomove(consbuffer, c, uio);
263 		if (error != 0)
264 			break;
265 		for (i = 0; i < c; i++) {
266 			msglogchar(consbuffer[i], pri);
267 			if (consbuffer[i] == '\n')
268 				nl = 1;
269 			else
270 				nl = 0;
271 		}
272 	}
273 	if (!nl)
274 		msglogchar('\n', pri);
275 	msgbuftrigger = 1;
276 	FREE(miov, M_TEMP);
277 	FREE(consbuffer, M_TEMP);
278 	return;
279 }
280 
281 int
282 printf(const char *fmt, ...)
283 {
284 	va_list ap;
285 	int savintr;
286 	struct putchar_arg pca;
287 	int retval;
288 
289 	savintr = consintr;		/* disable interrupts */
290 	consintr = 0;
291 	va_start(ap, fmt);
292 	pca.tty = NULL;
293 	pca.flags = TOCONS | TOLOG;
294 	pca.pri = -1;
295 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
296 	va_end(ap);
297 	if (!panicstr)
298 		msgbuftrigger = 1;
299 	consintr = savintr;		/* reenable interrupts */
300 	return (retval);
301 }
302 
303 int
304 vprintf(const char *fmt, va_list ap)
305 {
306 	int savintr;
307 	struct putchar_arg pca;
308 	int retval;
309 
310 	savintr = consintr;		/* disable interrupts */
311 	consintr = 0;
312 	pca.tty = NULL;
313 	pca.flags = TOCONS | TOLOG;
314 	pca.pri = -1;
315 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
316 	if (!panicstr)
317 		msgbuftrigger = 1;
318 	consintr = savintr;		/* reenable interrupts */
319 	return (retval);
320 }
321 
322 /*
323  * Print a character on console or users terminal.  If destination is
324  * the console then the last bunch of characters are saved in msgbuf for
325  * inspection later.
326  */
327 static void
328 putchar(int c, void *arg)
329 {
330 	struct putchar_arg *ap = (struct putchar_arg*) arg;
331 	struct tty *tp = ap->tty;
332 	int consdirect, flags = ap->flags;
333 
334 	consdirect = ((flags & TOCONS) && constty == NULL);
335 	/* Don't use the tty code after a panic or while in ddb. */
336 	if (panicstr)
337 		consdirect = 1;
338 #ifdef DDB
339 	if (db_active)
340 		consdirect = 1;
341 #endif
342 	if (consdirect) {
343 		if (c != '\0')
344 			cnputc(c);
345 	} else {
346 		if ((flags & TOTTY) && tp != NULL)
347 			tputchar(c, tp);
348 		if ((flags & TOCONS) && constty != NULL)
349 			msgbuf_addchar(&consmsgbuf, c);
350 	}
351 	if ((flags & TOLOG))
352 		msglogchar(c, ap->pri);
353 }
354 
355 /*
356  * Scaled down version of sprintf(3).
357  */
358 int
359 sprintf(char *buf, const char *cfmt, ...)
360 {
361 	int retval;
362 	va_list ap;
363 
364 	va_start(ap, cfmt);
365 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
366 	buf[retval] = '\0';
367 	va_end(ap);
368 	return (retval);
369 }
370 
371 /*
372  * Scaled down version of vsprintf(3).
373  */
374 int
375 vsprintf(char *buf, const char *cfmt, va_list ap)
376 {
377 	int retval;
378 
379 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
380 	buf[retval] = '\0';
381 	return (retval);
382 }
383 
384 /*
385  * Scaled down version of snprintf(3).
386  */
387 int
388 snprintf(char *str, size_t size, const char *format, ...)
389 {
390 	int retval;
391 	va_list ap;
392 
393 	va_start(ap, format);
394 	retval = vsnprintf(str, size, format, ap);
395 	va_end(ap);
396 	return(retval);
397 }
398 
399 /*
400  * Scaled down version of vsnprintf(3).
401  */
402 int
403 vsnprintf(char *str, size_t size, const char *format, va_list ap)
404 {
405 	struct snprintf_arg info;
406 	int retval;
407 
408 	info.str = str;
409 	info.remain = size;
410 	retval = kvprintf(format, snprintf_func, &info, 10, ap);
411 	if (info.remain >= 1)
412 		*info.str++ = '\0';
413 	return (retval);
414 }
415 
416 /*
417  * Kernel version which takes radix argument vsnprintf(3).
418  */
419 int
420 vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
421 {
422 	struct snprintf_arg info;
423 	int retval;
424 
425 	info.str = str;
426 	info.remain = size;
427 	retval = kvprintf(format, snprintf_func, &info, radix, ap);
428 	if (info.remain >= 1)
429 		*info.str++ = '\0';
430 	return (retval);
431 }
432 
433 static void
434 snprintf_func(int ch, void *arg)
435 {
436 	struct snprintf_arg *const info = arg;
437 
438 	if (info->remain >= 2) {
439 		*info->str++ = ch;
440 		info->remain--;
441 	}
442 }
443 
444 /*
445  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
446  * order; return an optional length and a pointer to the last character
447  * written in the buffer (i.e., the first character of the string).
448  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
449  */
450 static char *
451 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp)
452 {
453 	char *p;
454 
455 	p = nbuf;
456 	*p = '\0';
457 	do {
458 		*++p = hex2ascii(num % base);
459 	} while (num /= base);
460 	if (lenp)
461 		*lenp = p - nbuf;
462 	return (p);
463 }
464 
465 /*
466  * Scaled down version of printf(3).
467  *
468  * Two additional formats:
469  *
470  * The format %b is supported to decode error registers.
471  * Its usage is:
472  *
473  *	printf("reg=%b\n", regval, "<base><arg>*");
474  *
475  * where <base> is the output base expressed as a control character, e.g.
476  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
477  * the first of which gives the bit number to be inspected (origin 1), and
478  * the next characters (up to a control character, i.e. a character <= 32),
479  * give the name of the register.  Thus:
480  *
481  *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
482  *
483  * would produce output:
484  *
485  *	reg=3<BITTWO,BITONE>
486  *
487  * XXX:  %D  -- Hexdump, takes pointer and separator string:
488  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
489  *		("%*D", len, ptr, " " -> XX XX XX XX ...
490  */
491 int
492 kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
493 {
494 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
495 	char nbuf[MAXNBUF];
496 	char *d;
497 	const char *p, *percent, *q;
498 	u_char *up;
499 	int ch, n;
500 	uintmax_t num;
501 	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
502 	int cflag, hflag, jflag, tflag, zflag;
503 	int dwidth;
504 	char padc;
505 	int retval = 0;
506 
507 	num = 0;
508 	if (!func)
509 		d = (char *) arg;
510 	else
511 		d = NULL;
512 
513 	if (fmt == NULL)
514 		fmt = "(fmt null)\n";
515 
516 	if (radix < 2 || radix > 36)
517 		radix = 10;
518 
519 	for (;;) {
520 		padc = ' ';
521 		width = 0;
522 		while ((ch = (u_char)*fmt++) != '%') {
523 			if (ch == '\0')
524 				return (retval);
525 			PCHAR(ch);
526 		}
527 		percent = fmt - 1;
528 		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
529 		sign = 0; dot = 0; dwidth = 0;
530 		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
531 reswitch:	switch (ch = (u_char)*fmt++) {
532 		case '.':
533 			dot = 1;
534 			goto reswitch;
535 		case '#':
536 			sharpflag = 1;
537 			goto reswitch;
538 		case '+':
539 			sign = 1;
540 			goto reswitch;
541 		case '-':
542 			ladjust = 1;
543 			goto reswitch;
544 		case '%':
545 			PCHAR(ch);
546 			break;
547 		case '*':
548 			if (!dot) {
549 				width = va_arg(ap, int);
550 				if (width < 0) {
551 					ladjust = !ladjust;
552 					width = -width;
553 				}
554 			} else {
555 				dwidth = va_arg(ap, int);
556 			}
557 			goto reswitch;
558 		case '0':
559 			if (!dot) {
560 				padc = '0';
561 				goto reswitch;
562 			}
563 		case '1': case '2': case '3': case '4':
564 		case '5': case '6': case '7': case '8': case '9':
565 				for (n = 0;; ++fmt) {
566 					n = n * 10 + ch - '0';
567 					ch = *fmt;
568 					if (ch < '0' || ch > '9')
569 						break;
570 				}
571 			if (dot)
572 				dwidth = n;
573 			else
574 				width = n;
575 			goto reswitch;
576 		case 'b':
577 			num = (u_int)va_arg(ap, int);
578 			p = va_arg(ap, char *);
579 			for (q = ksprintn(nbuf, num, *p++, NULL); *q;)
580 				PCHAR(*q--);
581 
582 			if (num == 0)
583 				break;
584 
585 			for (tmp = 0; *p;) {
586 				n = *p++;
587 				if (num & (1 << (n - 1))) {
588 					PCHAR(tmp ? ',' : '<');
589 					for (; (n = *p) > ' '; ++p)
590 						PCHAR(n);
591 					tmp = 1;
592 				} else
593 					for (; *p > ' '; ++p)
594 						continue;
595 			}
596 			if (tmp)
597 				PCHAR('>');
598 			break;
599 		case 'c':
600 			PCHAR(va_arg(ap, int));
601 			break;
602 		case 'D':
603 			up = va_arg(ap, u_char *);
604 			p = va_arg(ap, char *);
605 			if (!width)
606 				width = 16;
607 			while(width--) {
608 				PCHAR(hex2ascii(*up >> 4));
609 				PCHAR(hex2ascii(*up & 0x0f));
610 				up++;
611 				if (width)
612 					for (q=p;*q;q++)
613 						PCHAR(*q);
614 			}
615 			break;
616 		case 'd':
617 		case 'i':
618 			base = 10;
619 			sign = 1;
620 			goto handle_sign;
621 		case 'h':
622 			if (hflag) {
623 				hflag = 0;
624 				cflag = 1;
625 			} else
626 				hflag = 1;
627 			goto reswitch;
628 		case 'j':
629 			jflag = 1;
630 			goto reswitch;
631 		case 'l':
632 			if (lflag) {
633 				lflag = 0;
634 				qflag = 1;
635 			} else
636 				lflag = 1;
637 			goto reswitch;
638 		case 'n':
639 			if (jflag)
640 				*(va_arg(ap, intmax_t *)) = retval;
641 			else if (qflag)
642 				*(va_arg(ap, quad_t *)) = retval;
643 			else if (lflag)
644 				*(va_arg(ap, long *)) = retval;
645 			else if (zflag)
646 				*(va_arg(ap, size_t *)) = retval;
647 			else if (hflag)
648 				*(va_arg(ap, short *)) = retval;
649 			else if (cflag)
650 				*(va_arg(ap, char *)) = retval;
651 			else
652 				*(va_arg(ap, int *)) = retval;
653 			break;
654 		case 'o':
655 			base = 8;
656 			goto handle_nosign;
657 		case 'p':
658 			base = 16;
659 			sharpflag = (width == 0);
660 			sign = 0;
661 			num = (uintptr_t)va_arg(ap, void *);
662 			goto number;
663 		case 'q':
664 			qflag = 1;
665 			goto reswitch;
666 		case 'r':
667 			base = radix;
668 			if (sign)
669 				goto handle_sign;
670 			goto handle_nosign;
671 		case 's':
672 			p = va_arg(ap, char *);
673 			if (p == NULL)
674 				p = "(null)";
675 			if (!dot)
676 				n = strlen (p);
677 			else
678 				for (n = 0; n < dwidth && p[n]; n++)
679 					continue;
680 
681 			width -= n;
682 
683 			if (!ladjust && width > 0)
684 				while (width--)
685 					PCHAR(padc);
686 			while (n--)
687 				PCHAR(*p++);
688 			if (ladjust && width > 0)
689 				while (width--)
690 					PCHAR(padc);
691 			break;
692 		case 't':
693 			tflag = 1;
694 			goto reswitch;
695 		case 'u':
696 			base = 10;
697 			goto handle_nosign;
698 		case 'x':
699 		case 'X':
700 			base = 16;
701 			goto handle_nosign;
702 		case 'y':
703 			base = 16;
704 			sign = 1;
705 			goto handle_sign;
706 		case 'z':
707 			zflag = 1;
708 			goto reswitch;
709 handle_nosign:
710 			sign = 0;
711 			if (jflag)
712 				num = va_arg(ap, uintmax_t);
713 			else if (qflag)
714 				num = va_arg(ap, u_quad_t);
715 			else if (tflag)
716 				num = va_arg(ap, ptrdiff_t);
717 			else if (lflag)
718 				num = va_arg(ap, u_long);
719 			else if (zflag)
720 				num = va_arg(ap, size_t);
721 			else if (hflag)
722 				num = (u_short)va_arg(ap, int);
723 			else if (cflag)
724 				num = (u_char)va_arg(ap, int);
725 			else
726 				num = va_arg(ap, u_int);
727 			goto number;
728 handle_sign:
729 			if (jflag)
730 				num = va_arg(ap, intmax_t);
731 			else if (qflag)
732 				num = va_arg(ap, quad_t);
733 			else if (tflag)
734 				num = va_arg(ap, ptrdiff_t);
735 			else if (lflag)
736 				num = va_arg(ap, long);
737 			else if (zflag)
738 				num = va_arg(ap, size_t);
739 			else if (hflag)
740 				num = (short)va_arg(ap, int);
741 			else if (cflag)
742 				num = (char)va_arg(ap, int);
743 			else
744 				num = va_arg(ap, int);
745 number:
746 			if (sign && (intmax_t)num < 0) {
747 				neg = 1;
748 				num = -(intmax_t)num;
749 			}
750 			p = ksprintn(nbuf, num, base, &tmp);
751 			if (sharpflag && num != 0) {
752 				if (base == 8)
753 					tmp++;
754 				else if (base == 16)
755 					tmp += 2;
756 			}
757 			if (neg)
758 				tmp++;
759 
760 			if (!ladjust && width && (width -= tmp) > 0)
761 				while (width--)
762 					PCHAR(padc);
763 			if (neg)
764 				PCHAR('-');
765 			if (sharpflag && num != 0) {
766 				if (base == 8) {
767 					PCHAR('0');
768 				} else if (base == 16) {
769 					PCHAR('0');
770 					PCHAR('x');
771 				}
772 			}
773 
774 			while (*p)
775 				PCHAR(*p--);
776 
777 			if (ladjust && width && (width -= tmp) > 0)
778 				while (width--)
779 					PCHAR(padc);
780 
781 			break;
782 		default:
783 			while (percent < fmt)
784 				PCHAR(*percent++);
785 			break;
786 		}
787 	}
788 #undef PCHAR
789 }
790 
791 /*
792  * Put character in log buffer with a particular priority.
793  */
794 static void
795 msglogchar(int c, int pri)
796 {
797 	static int lastpri = -1;
798 	static int dangling;
799 	char nbuf[MAXNBUF];
800 	char *p;
801 
802 	if (!msgbufmapped)
803 		return;
804 	if (c == '\0' || c == '\r')
805 		return;
806 	if (pri != -1 && pri != lastpri) {
807 		if (dangling) {
808 			msgbuf_addchar(msgbufp, '\n');
809 			dangling = 0;
810 		}
811 		msgbuf_addchar(msgbufp, '<');
812 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL); *p;)
813 			msgbuf_addchar(msgbufp, *p--);
814 		msgbuf_addchar(msgbufp, '>');
815 		lastpri = pri;
816 	}
817 	msgbuf_addchar(msgbufp, c);
818 	if (c == '\n') {
819 		dangling = 0;
820 		lastpri = -1;
821 	} else {
822 		dangling = 1;
823 	}
824 }
825 
826 void
827 msgbufinit(void *ptr, int size)
828 {
829 	char *cp;
830 	static struct msgbuf *oldp = NULL;
831 
832 	size -= sizeof(*msgbufp);
833 	cp = (char *)ptr;
834 	msgbufp = (struct msgbuf *)(cp + size);
835 	msgbuf_reinit(msgbufp, cp, size);
836 	if (msgbufmapped && oldp != msgbufp)
837 		msgbuf_copy(oldp, msgbufp);
838 	msgbufmapped = 1;
839 	oldp = msgbufp;
840 }
841 
842 SYSCTL_DECL(_security_bsd);
843 
844 static int unprivileged_read_msgbuf = 1;
845 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_read_msgbuf,
846     CTLFLAG_RW, &unprivileged_read_msgbuf, 0,
847     "Unprivileged processes may read the kernel message buffer");
848 
849 /* Sysctls for accessing/clearing the msgbuf */
850 static int
851 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
852 {
853 	char buf[128];
854 	u_int seq;
855 	int error, len;
856 
857 	if (!unprivileged_read_msgbuf) {
858 		error = suser(req->td);
859 		if (error)
860 			return (error);
861 	}
862 
863 	/* Read the whole buffer, one chunk at a time. */
864 	msgbuf_peekbytes(msgbufp, NULL, 0, &seq);
865 	while ((len = msgbuf_peekbytes(msgbufp, buf, sizeof(buf), &seq)) > 0) {
866 		error = sysctl_handle_opaque(oidp, buf, len, req);
867 		if (error)
868 			return (error);
869 	}
870 	return (0);
871 }
872 
873 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
874     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
875 
876 static int msgbuf_clearflag;
877 
878 static int
879 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
880 {
881 	int error;
882 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
883 	if (!error && req->newptr) {
884 		msgbuf_clear(msgbufp);
885 		msgbuf_clearflag = 0;
886 	}
887 	return (error);
888 }
889 
890 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
891     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clearflag, 0,
892     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
893 
894 #ifdef DDB
895 
896 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
897 {
898 	int i, j;
899 
900 	if (!msgbufmapped) {
901 		db_printf("msgbuf not mapped yet\n");
902 		return;
903 	}
904 	db_printf("msgbufp = %p\n", msgbufp);
905 	db_printf("magic = %x, size = %d, r= %u, w = %u, ptr = %p, cksum= %u\n",
906 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_rseq,
907 	    msgbufp->msg_wseq, msgbufp->msg_ptr, msgbufp->msg_cksum);
908 	for (i = 0; i < msgbufp->msg_size; i++) {
909 		j = MSGBUF_SEQ_TO_POS(msgbufp, i + msgbufp->msg_rseq);
910 		db_printf("%c", msgbufp->msg_ptr[j]);
911 	}
912 	db_printf("\n");
913 }
914 
915 #endif /* DDB */
916 
917 void
918 hexdump(void *ptr, int length, const char *hdr, int flags)
919 {
920 	int i, j, k;
921 	int cols;
922 	unsigned char *cp;
923 	char delim;
924 
925 	if ((flags & HD_DELIM_MASK) != 0)
926 		delim = (flags & HD_DELIM_MASK) >> 8;
927 	else
928 		delim = ' ';
929 
930 	if ((flags & HD_COLUMN_MASK) != 0)
931 		cols = flags & HD_COLUMN_MASK;
932 	else
933 		cols = 16;
934 
935 	cp = ptr;
936 	for (i = 0; i < length; i+= cols) {
937 		if (hdr != NULL)
938 			printf("%s", hdr);
939 
940 		if ((flags & HD_OMIT_COUNT) == 0)
941 			printf("%04x  ", i);
942 
943 		if ((flags & HD_OMIT_HEX) == 0) {
944 			for (j = 0; j < cols; j++) {
945 				k = i + j;
946 				if (k < length)
947 					printf("%c%02x", delim, cp[k]);
948 				else
949 					printf("   ");
950 			}
951 		}
952 
953 		if ((flags & HD_OMIT_CHARS) == 0) {
954 			printf("  |");
955 			for (j = 0; j < cols; j++) {
956 				k = i + j;
957 				if (k >= length)
958 					printf(" ");
959 				else if (cp[k] >= ' ' && cp[k] <= '~')
960 					printf("%c", cp[k]);
961 				else
962 					printf(".");
963 			}
964 			printf("|\n");
965 		}
966 	}
967 }
968 
969