xref: /freebsd/sys/kern/subr_prf.c (revision 3642298923e528d795e3a30ec165d2b469e28b40)
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/kdb.h>
46 #include <sys/mutex.h>
47 #include <sys/sx.h>
48 #include <sys/kernel.h>
49 #include <sys/msgbuf.h>
50 #include <sys/malloc.h>
51 #include <sys/proc.h>
52 #include <sys/stddef.h>
53 #include <sys/sysctl.h>
54 #include <sys/tty.h>
55 #include <sys/syslog.h>
56 #include <sys/cons.h>
57 #include <sys/uio.h>
58 
59 #ifdef DDB
60 #include <ddb/ddb.h>
61 #endif
62 
63 /*
64  * Note that stdarg.h and the ANSI style va_start macro is used for both
65  * ANSI and traditional C compilers.
66  */
67 #include <machine/stdarg.h>
68 
69 #define TOCONS	0x01
70 #define TOTTY	0x02
71 #define TOLOG	0x04
72 
73 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
74 #define MAXNBUF	(sizeof(intmax_t) * NBBY + 1)
75 
76 struct putchar_arg {
77 	int	flags;
78 	int	pri;
79 	struct	tty *tty;
80 };
81 
82 struct snprintf_arg {
83 	char	*str;
84 	size_t	remain;
85 };
86 
87 extern	int log_open;
88 
89 static void  msglogchar(int c, int pri);
90 static void  putchar(int ch, void *arg);
91 static char *ksprintn(char *nbuf, uintmax_t num, int base, int *len);
92 static void  snprintf_func(int ch, void *arg);
93 
94 static int consintr = 1;		/* Ok to handle console interrupts? */
95 static int msgbufmapped;		/* Set when safe to use msgbuf */
96 int msgbuftrigger;
97 
98 static int      log_console_output = 1;
99 TUNABLE_INT("kern.log_console_output", &log_console_output);
100 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
101     &log_console_output, 0, "Duplicate console output to the syslog.");
102 
103 static int	always_console_output = 0;
104 TUNABLE_INT("kern.always_console_output", &always_console_output);
105 SYSCTL_INT(_kern, OID_AUTO, always_console_output, CTLFLAG_RW,
106     &always_console_output, 0, "Always output to console despite TIOCCONS.");
107 
108 /*
109  * Warn that a system table is full.
110  */
111 void
112 tablefull(const char *tab)
113 {
114 
115 	log(LOG_ERR, "%s: table is full\n", tab);
116 }
117 
118 /*
119  * Uprintf prints to the controlling terminal for the current process.
120  * It may block if the tty queue is overfull.  No message is printed if
121  * the queue does not clear in a reasonable time.
122  */
123 int
124 uprintf(const char *fmt, ...)
125 {
126 	struct thread *td = curthread;
127 	struct proc *p = td->td_proc;
128 	va_list ap;
129 	struct putchar_arg pca;
130 	int retval;
131 
132 	GIANT_REQUIRED;
133 
134 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "uprintf");
135 
136 	if (td == NULL || td == PCPU_GET(idlethread))
137 		return (0);
138 
139 	p = td->td_proc;
140 	PROC_LOCK(p);
141 	if ((p->p_flag & P_CONTROLT) == 0) {
142 		PROC_UNLOCK(p);
143 		return (0);
144 	}
145 	SESS_LOCK(p->p_session);
146 	pca.tty = p->p_session->s_ttyp;
147 	SESS_UNLOCK(p->p_session);
148 	PROC_UNLOCK(p);
149 	if (pca.tty == NULL)
150 		return (0);
151 	pca.flags = TOTTY;
152 	va_start(ap, fmt);
153 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
154 	va_end(ap);
155 
156 	return (retval);
157 }
158 
159 /*
160  * tprintf prints on the controlling terminal associated
161  * with the given session, possibly to the log as well.
162  */
163 void
164 tprintf(struct proc *p, int pri, const char *fmt, ...)
165 {
166 	struct tty *tp = NULL;
167 	int flags = 0;
168 	va_list ap;
169 	struct putchar_arg pca;
170 	struct session *sess = NULL;
171 
172 	GIANT_REQUIRED;
173 
174 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "tprintf");
175 
176 	if (pri != -1)
177 		flags |= TOLOG;
178 	if (p != NULL) {
179 		PROC_LOCK(p);
180 		if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
181 			sess = p->p_session;
182 			SESS_LOCK(sess);
183 			PROC_UNLOCK(p);
184 			SESSHOLD(sess);
185 			tp = sess->s_ttyp;
186 			SESS_UNLOCK(sess);
187 			if (ttycheckoutq(tp, 0))
188 				flags |= TOTTY;
189 			else
190 				tp = NULL;
191 		} else
192 			PROC_UNLOCK(p);
193 	}
194 	pca.pri = pri;
195 	pca.tty = tp;
196 	pca.flags = flags;
197 	va_start(ap, fmt);
198 	kvprintf(fmt, putchar, &pca, 10, ap);
199 	va_end(ap);
200 	if (sess != NULL)
201 		SESSRELE(sess);
202 	msgbuftrigger = 1;
203 }
204 
205 /*
206  * Ttyprintf displays a message on a tty; it should be used only by
207  * the tty driver, or anything that knows the underlying tty will not
208  * be revoke(2)'d away.  Other callers should use tprintf.
209  */
210 int
211 ttyprintf(struct tty *tp, const char *fmt, ...)
212 {
213 	va_list ap;
214 	struct putchar_arg pca;
215 	int retval;
216 
217 	va_start(ap, fmt);
218 	pca.tty = tp;
219 	pca.flags = TOTTY;
220 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
221 	va_end(ap);
222 	return (retval);
223 }
224 
225 /*
226  * Log writes to the log buffer, and guarantees not to sleep (so can be
227  * called by interrupt routines).  If there is no process reading the
228  * log yet, it writes to the console also.
229  */
230 void
231 log(int level, const char *fmt, ...)
232 {
233 	va_list ap;
234 	struct putchar_arg pca;
235 
236 	pca.tty = NULL;
237 	pca.pri = level;
238 	pca.flags = log_open ? TOLOG : TOCONS;
239 
240 	va_start(ap, fmt);
241 	kvprintf(fmt, putchar, &pca, 10, ap);
242 	va_end(ap);
243 
244 	msgbuftrigger = 1;
245 }
246 
247 #define CONSCHUNK 128
248 
249 void
250 log_console(struct uio *uio)
251 {
252 	int c, i, error, nl;
253 	char *consbuffer;
254 	int pri;
255 
256 	if (!log_console_output)
257 		return;
258 
259 	pri = LOG_INFO | LOG_CONSOLE;
260 	uio = cloneuio(uio);
261 	consbuffer = malloc(CONSCHUNK, M_TEMP, M_WAITOK);
262 
263 	nl = 0;
264 	while (uio->uio_resid > 0) {
265 		c = imin(uio->uio_resid, CONSCHUNK);
266 		error = uiomove(consbuffer, c, uio);
267 		if (error != 0)
268 			break;
269 		for (i = 0; i < c; i++) {
270 			msglogchar(consbuffer[i], pri);
271 			if (consbuffer[i] == '\n')
272 				nl = 1;
273 			else
274 				nl = 0;
275 		}
276 	}
277 	if (!nl)
278 		msglogchar('\n', pri);
279 	msgbuftrigger = 1;
280 	free(uio, M_IOV);
281 	free(consbuffer, M_TEMP);
282 	return;
283 }
284 
285 int
286 printf(const char *fmt, ...)
287 {
288 	va_list ap;
289 	int savintr;
290 	struct putchar_arg pca;
291 	int retval;
292 
293 	savintr = consintr;		/* disable interrupts */
294 	consintr = 0;
295 	va_start(ap, fmt);
296 	pca.tty = NULL;
297 	pca.flags = TOCONS | TOLOG;
298 	pca.pri = -1;
299 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
300 	va_end(ap);
301 	if (!panicstr)
302 		msgbuftrigger = 1;
303 	consintr = savintr;		/* reenable interrupts */
304 	return (retval);
305 }
306 
307 int
308 vprintf(const char *fmt, va_list ap)
309 {
310 	int savintr;
311 	struct putchar_arg pca;
312 	int retval;
313 
314 	savintr = consintr;		/* disable interrupts */
315 	consintr = 0;
316 	pca.tty = NULL;
317 	pca.flags = TOCONS | TOLOG;
318 	pca.pri = -1;
319 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
320 	if (!panicstr)
321 		msgbuftrigger = 1;
322 	consintr = savintr;		/* reenable interrupts */
323 	return (retval);
324 }
325 
326 /*
327  * Print a character on console or users terminal.  If destination is
328  * the console then the last bunch of characters are saved in msgbuf for
329  * inspection later.
330  */
331 static void
332 putchar(int c, void *arg)
333 {
334 	struct putchar_arg *ap = (struct putchar_arg*) arg;
335 	struct tty *tp = ap->tty;
336 	int consdirect, flags = ap->flags;
337 
338 	consdirect = ((flags & TOCONS) && constty == NULL);
339 	/* Don't use the tty code after a panic or while in ddb. */
340 	if (panicstr)
341 		consdirect = 1;
342 	if (kdb_active)
343 		consdirect = 1;
344 	if (consdirect) {
345 		if (c != '\0')
346 			cnputc(c);
347 	} else {
348 		if ((flags & TOTTY) && tp != NULL)
349 			tputchar(c, tp);
350 		if (flags & TOCONS) {
351 			if (constty != NULL)
352 				msgbuf_addchar(&consmsgbuf, c);
353 			if (always_console_output && c != '\0')
354 				cnputc(c);
355 		}
356 	}
357 	if ((flags & TOLOG))
358 		msglogchar(c, ap->pri);
359 }
360 
361 /*
362  * Scaled down version of sprintf(3).
363  */
364 int
365 sprintf(char *buf, const char *cfmt, ...)
366 {
367 	int retval;
368 	va_list ap;
369 
370 	va_start(ap, cfmt);
371 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
372 	buf[retval] = '\0';
373 	va_end(ap);
374 	return (retval);
375 }
376 
377 /*
378  * Scaled down version of vsprintf(3).
379  */
380 int
381 vsprintf(char *buf, const char *cfmt, va_list ap)
382 {
383 	int retval;
384 
385 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
386 	buf[retval] = '\0';
387 	return (retval);
388 }
389 
390 /*
391  * Scaled down version of snprintf(3).
392  */
393 int
394 snprintf(char *str, size_t size, const char *format, ...)
395 {
396 	int retval;
397 	va_list ap;
398 
399 	va_start(ap, format);
400 	retval = vsnprintf(str, size, format, ap);
401 	va_end(ap);
402 	return(retval);
403 }
404 
405 /*
406  * Scaled down version of vsnprintf(3).
407  */
408 int
409 vsnprintf(char *str, size_t size, const char *format, va_list ap)
410 {
411 	struct snprintf_arg info;
412 	int retval;
413 
414 	info.str = str;
415 	info.remain = size;
416 	retval = kvprintf(format, snprintf_func, &info, 10, ap);
417 	if (info.remain >= 1)
418 		*info.str++ = '\0';
419 	return (retval);
420 }
421 
422 /*
423  * Kernel version which takes radix argument vsnprintf(3).
424  */
425 int
426 vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
427 {
428 	struct snprintf_arg info;
429 	int retval;
430 
431 	info.str = str;
432 	info.remain = size;
433 	retval = kvprintf(format, snprintf_func, &info, radix, ap);
434 	if (info.remain >= 1)
435 		*info.str++ = '\0';
436 	return (retval);
437 }
438 
439 static void
440 snprintf_func(int ch, void *arg)
441 {
442 	struct snprintf_arg *const info = arg;
443 
444 	if (info->remain >= 2) {
445 		*info->str++ = ch;
446 		info->remain--;
447 	}
448 }
449 
450 /*
451  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
452  * order; return an optional length and a pointer to the last character
453  * written in the buffer (i.e., the first character of the string).
454  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
455  */
456 static char *
457 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp)
458 {
459 	char *p;
460 
461 	p = nbuf;
462 	*p = '\0';
463 	do {
464 		*++p = hex2ascii(num % base);
465 	} while (num /= base);
466 	if (lenp)
467 		*lenp = p - nbuf;
468 	return (p);
469 }
470 
471 /*
472  * Scaled down version of printf(3).
473  *
474  * Two additional formats:
475  *
476  * The format %b is supported to decode error registers.
477  * Its usage is:
478  *
479  *	printf("reg=%b\n", regval, "<base><arg>*");
480  *
481  * where <base> is the output base expressed as a control character, e.g.
482  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
483  * the first of which gives the bit number to be inspected (origin 1), and
484  * the next characters (up to a control character, i.e. a character <= 32),
485  * give the name of the register.  Thus:
486  *
487  *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
488  *
489  * would produce output:
490  *
491  *	reg=3<BITTWO,BITONE>
492  *
493  * XXX:  %D  -- Hexdump, takes pointer and separator string:
494  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
495  *		("%*D", len, ptr, " " -> XX XX XX XX ...
496  */
497 int
498 kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
499 {
500 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
501 	char nbuf[MAXNBUF];
502 	char *d;
503 	const char *p, *percent, *q;
504 	u_char *up;
505 	int ch, n;
506 	uintmax_t num;
507 	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
508 	int cflag, hflag, jflag, tflag, zflag;
509 	int dwidth;
510 	char padc;
511 	int stop = 0, retval = 0;
512 
513 	num = 0;
514 	if (!func)
515 		d = (char *) arg;
516 	else
517 		d = NULL;
518 
519 	if (fmt == NULL)
520 		fmt = "(fmt null)\n";
521 
522 	if (radix < 2 || radix > 36)
523 		radix = 10;
524 
525 	for (;;) {
526 		padc = ' ';
527 		width = 0;
528 		while ((ch = (u_char)*fmt++) != '%' || stop) {
529 			if (ch == '\0')
530 				return (retval);
531 			PCHAR(ch);
532 		}
533 		percent = fmt - 1;
534 		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
535 		sign = 0; dot = 0; dwidth = 0;
536 		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
537 reswitch:	switch (ch = (u_char)*fmt++) {
538 		case '.':
539 			dot = 1;
540 			goto reswitch;
541 		case '#':
542 			sharpflag = 1;
543 			goto reswitch;
544 		case '+':
545 			sign = 1;
546 			goto reswitch;
547 		case '-':
548 			ladjust = 1;
549 			goto reswitch;
550 		case '%':
551 			PCHAR(ch);
552 			break;
553 		case '*':
554 			if (!dot) {
555 				width = va_arg(ap, int);
556 				if (width < 0) {
557 					ladjust = !ladjust;
558 					width = -width;
559 				}
560 			} else {
561 				dwidth = va_arg(ap, int);
562 			}
563 			goto reswitch;
564 		case '0':
565 			if (!dot) {
566 				padc = '0';
567 				goto reswitch;
568 			}
569 		case '1': case '2': case '3': case '4':
570 		case '5': case '6': case '7': case '8': case '9':
571 				for (n = 0;; ++fmt) {
572 					n = n * 10 + ch - '0';
573 					ch = *fmt;
574 					if (ch < '0' || ch > '9')
575 						break;
576 				}
577 			if (dot)
578 				dwidth = n;
579 			else
580 				width = n;
581 			goto reswitch;
582 		case 'b':
583 			num = (u_int)va_arg(ap, int);
584 			p = va_arg(ap, char *);
585 			for (q = ksprintn(nbuf, num, *p++, NULL); *q;)
586 				PCHAR(*q--);
587 
588 			if (num == 0)
589 				break;
590 
591 			for (tmp = 0; *p;) {
592 				n = *p++;
593 				if (num & (1 << (n - 1))) {
594 					PCHAR(tmp ? ',' : '<');
595 					for (; (n = *p) > ' '; ++p)
596 						PCHAR(n);
597 					tmp = 1;
598 				} else
599 					for (; *p > ' '; ++p)
600 						continue;
601 			}
602 			if (tmp)
603 				PCHAR('>');
604 			break;
605 		case 'c':
606 			PCHAR(va_arg(ap, int));
607 			break;
608 		case 'D':
609 			up = va_arg(ap, u_char *);
610 			p = va_arg(ap, char *);
611 			if (!width)
612 				width = 16;
613 			while(width--) {
614 				PCHAR(hex2ascii(*up >> 4));
615 				PCHAR(hex2ascii(*up & 0x0f));
616 				up++;
617 				if (width)
618 					for (q=p;*q;q++)
619 						PCHAR(*q);
620 			}
621 			break;
622 		case 'd':
623 		case 'i':
624 			base = 10;
625 			sign = 1;
626 			goto handle_sign;
627 		case 'h':
628 			if (hflag) {
629 				hflag = 0;
630 				cflag = 1;
631 			} else
632 				hflag = 1;
633 			goto reswitch;
634 		case 'j':
635 			jflag = 1;
636 			goto reswitch;
637 		case 'l':
638 			if (lflag) {
639 				lflag = 0;
640 				qflag = 1;
641 			} else
642 				lflag = 1;
643 			goto reswitch;
644 		case 'n':
645 			if (jflag)
646 				*(va_arg(ap, intmax_t *)) = retval;
647 			else if (qflag)
648 				*(va_arg(ap, quad_t *)) = retval;
649 			else if (lflag)
650 				*(va_arg(ap, long *)) = retval;
651 			else if (zflag)
652 				*(va_arg(ap, size_t *)) = retval;
653 			else if (hflag)
654 				*(va_arg(ap, short *)) = retval;
655 			else if (cflag)
656 				*(va_arg(ap, char *)) = retval;
657 			else
658 				*(va_arg(ap, int *)) = retval;
659 			break;
660 		case 'o':
661 			base = 8;
662 			goto handle_nosign;
663 		case 'p':
664 			base = 16;
665 			sharpflag = (width == 0);
666 			sign = 0;
667 			num = (uintptr_t)va_arg(ap, void *);
668 			goto number;
669 		case 'q':
670 			qflag = 1;
671 			goto reswitch;
672 		case 'r':
673 			base = radix;
674 			if (sign)
675 				goto handle_sign;
676 			goto handle_nosign;
677 		case 's':
678 			p = va_arg(ap, char *);
679 			if (p == NULL)
680 				p = "(null)";
681 			if (!dot)
682 				n = strlen (p);
683 			else
684 				for (n = 0; n < dwidth && p[n]; n++)
685 					continue;
686 
687 			width -= n;
688 
689 			if (!ladjust && width > 0)
690 				while (width--)
691 					PCHAR(padc);
692 			while (n--)
693 				PCHAR(*p++);
694 			if (ladjust && width > 0)
695 				while (width--)
696 					PCHAR(padc);
697 			break;
698 		case 't':
699 			tflag = 1;
700 			goto reswitch;
701 		case 'u':
702 			base = 10;
703 			goto handle_nosign;
704 		case 'x':
705 		case 'X':
706 			base = 16;
707 			goto handle_nosign;
708 		case 'y':
709 			base = 16;
710 			sign = 1;
711 			goto handle_sign;
712 		case 'z':
713 			zflag = 1;
714 			goto reswitch;
715 handle_nosign:
716 			sign = 0;
717 			if (jflag)
718 				num = va_arg(ap, uintmax_t);
719 			else if (qflag)
720 				num = va_arg(ap, u_quad_t);
721 			else if (tflag)
722 				num = va_arg(ap, ptrdiff_t);
723 			else if (lflag)
724 				num = va_arg(ap, u_long);
725 			else if (zflag)
726 				num = va_arg(ap, size_t);
727 			else if (hflag)
728 				num = (u_short)va_arg(ap, int);
729 			else if (cflag)
730 				num = (u_char)va_arg(ap, int);
731 			else
732 				num = va_arg(ap, u_int);
733 			goto number;
734 handle_sign:
735 			if (jflag)
736 				num = va_arg(ap, intmax_t);
737 			else if (qflag)
738 				num = va_arg(ap, quad_t);
739 			else if (tflag)
740 				num = va_arg(ap, ptrdiff_t);
741 			else if (lflag)
742 				num = va_arg(ap, long);
743 			else if (zflag)
744 				num = va_arg(ap, size_t);
745 			else if (hflag)
746 				num = (short)va_arg(ap, int);
747 			else if (cflag)
748 				num = (char)va_arg(ap, int);
749 			else
750 				num = va_arg(ap, int);
751 number:
752 			if (sign && (intmax_t)num < 0) {
753 				neg = 1;
754 				num = -(intmax_t)num;
755 			}
756 			p = ksprintn(nbuf, num, base, &tmp);
757 			if (sharpflag && num != 0) {
758 				if (base == 8)
759 					tmp++;
760 				else if (base == 16)
761 					tmp += 2;
762 			}
763 			if (neg)
764 				tmp++;
765 
766 			if (!ladjust && padc != '0' && width
767 			    && (width -= tmp) > 0)
768 				while (width--)
769 					PCHAR(padc);
770 			if (neg)
771 				PCHAR('-');
772 			if (sharpflag && num != 0) {
773 				if (base == 8) {
774 					PCHAR('0');
775 				} else if (base == 16) {
776 					PCHAR('0');
777 					PCHAR('x');
778 				}
779 			}
780 			if (!ladjust && width && (width -= tmp) > 0)
781 				while (width--)
782 					PCHAR(padc);
783 
784 			while (*p)
785 				PCHAR(*p--);
786 
787 			if (ladjust && width && (width -= tmp) > 0)
788 				while (width--)
789 					PCHAR(padc);
790 
791 			break;
792 		default:
793 			while (percent < fmt)
794 				PCHAR(*percent++);
795 			/*
796 			 * Since we ignore an formatting argument it is no
797 			 * longer safe to obey the remaining formatting
798 			 * arguments as the arguments will no longer match
799 			 * the format specs.
800 			 */
801 			stop = 1;
802 			break;
803 		}
804 	}
805 #undef PCHAR
806 }
807 
808 /*
809  * Put character in log buffer with a particular priority.
810  */
811 static void
812 msglogchar(int c, int pri)
813 {
814 	static int lastpri = -1;
815 	static int dangling;
816 	char nbuf[MAXNBUF];
817 	char *p;
818 
819 	if (!msgbufmapped)
820 		return;
821 	if (c == '\0' || c == '\r')
822 		return;
823 	if (pri != -1 && pri != lastpri) {
824 		if (dangling) {
825 			msgbuf_addchar(msgbufp, '\n');
826 			dangling = 0;
827 		}
828 		msgbuf_addchar(msgbufp, '<');
829 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL); *p;)
830 			msgbuf_addchar(msgbufp, *p--);
831 		msgbuf_addchar(msgbufp, '>');
832 		lastpri = pri;
833 	}
834 	msgbuf_addchar(msgbufp, c);
835 	if (c == '\n') {
836 		dangling = 0;
837 		lastpri = -1;
838 	} else {
839 		dangling = 1;
840 	}
841 }
842 
843 void
844 msgbufinit(void *ptr, int size)
845 {
846 	char *cp;
847 	static struct msgbuf *oldp = NULL;
848 
849 	size -= sizeof(*msgbufp);
850 	cp = (char *)ptr;
851 	msgbufp = (struct msgbuf *)(cp + size);
852 	msgbuf_reinit(msgbufp, cp, size);
853 	if (msgbufmapped && oldp != msgbufp)
854 		msgbuf_copy(oldp, msgbufp);
855 	msgbufmapped = 1;
856 	oldp = msgbufp;
857 }
858 
859 SYSCTL_DECL(_security_bsd);
860 
861 static int unprivileged_read_msgbuf = 1;
862 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_read_msgbuf,
863     CTLFLAG_RW, &unprivileged_read_msgbuf, 0,
864     "Unprivileged processes may read the kernel message buffer");
865 
866 /* Sysctls for accessing/clearing the msgbuf */
867 static int
868 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
869 {
870 	char buf[128];
871 	u_int seq;
872 	int error, len;
873 
874 	if (!unprivileged_read_msgbuf) {
875 		error = suser(req->td);
876 		if (error)
877 			return (error);
878 	}
879 
880 	/* Read the whole buffer, one chunk at a time. */
881 	msgbuf_peekbytes(msgbufp, NULL, 0, &seq);
882 	while ((len = msgbuf_peekbytes(msgbufp, buf, sizeof(buf), &seq)) > 0) {
883 		error = sysctl_handle_opaque(oidp, buf, len, req);
884 		if (error)
885 			return (error);
886 	}
887 	return (0);
888 }
889 
890 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
891     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
892 
893 static int msgbuf_clearflag;
894 
895 static int
896 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
897 {
898 	int error;
899 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
900 	if (!error && req->newptr) {
901 		msgbuf_clear(msgbufp);
902 		msgbuf_clearflag = 0;
903 	}
904 	return (error);
905 }
906 
907 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
908     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clearflag, 0,
909     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
910 
911 #ifdef DDB
912 
913 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
914 {
915 	int i, j, quit;
916 
917 	quit = 0;
918 
919 	if (!msgbufmapped) {
920 		db_printf("msgbuf not mapped yet\n");
921 		return;
922 	}
923 	db_setup_paging(db_simple_pager, &quit, db_lines_per_page);
924 	db_printf("msgbufp = %p\n", msgbufp);
925 	db_printf("magic = %x, size = %d, r= %u, w = %u, ptr = %p, cksum= %u\n",
926 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_rseq,
927 	    msgbufp->msg_wseq, msgbufp->msg_ptr, msgbufp->msg_cksum);
928 	for (i = 0; i < msgbufp->msg_size && !quit; i++) {
929 		j = MSGBUF_SEQ_TO_POS(msgbufp, i + msgbufp->msg_rseq);
930 		db_printf("%c", msgbufp->msg_ptr[j]);
931 	}
932 	db_printf("\n");
933 }
934 
935 #endif /* DDB */
936 
937 void
938 hexdump(const void *ptr, int length, const char *hdr, int flags)
939 {
940 	int i, j, k;
941 	int cols;
942 	const unsigned char *cp;
943 	char delim;
944 
945 	if ((flags & HD_DELIM_MASK) != 0)
946 		delim = (flags & HD_DELIM_MASK) >> 8;
947 	else
948 		delim = ' ';
949 
950 	if ((flags & HD_COLUMN_MASK) != 0)
951 		cols = flags & HD_COLUMN_MASK;
952 	else
953 		cols = 16;
954 
955 	cp = ptr;
956 	for (i = 0; i < length; i+= cols) {
957 		if (hdr != NULL)
958 			printf("%s", hdr);
959 
960 		if ((flags & HD_OMIT_COUNT) == 0)
961 			printf("%04x  ", i);
962 
963 		if ((flags & HD_OMIT_HEX) == 0) {
964 			for (j = 0; j < cols; j++) {
965 				k = i + j;
966 				if (k < length)
967 					printf("%c%02x", delim, cp[k]);
968 				else
969 					printf("   ");
970 			}
971 		}
972 
973 		if ((flags & HD_OMIT_CHARS) == 0) {
974 			printf("  |");
975 			for (j = 0; j < cols; j++) {
976 				k = i + j;
977 				if (k >= length)
978 					printf(" ");
979 				else if (cp[k] >= ' ' && cp[k] <= '~')
980 					printf("%c", cp[k]);
981 				else
982 					printf(".");
983 			}
984 			printf("|\n");
985 		}
986 	}
987 }
988 
989