xref: /freebsd/sys/kern/subr_prf.c (revision d056fa046c6a91b90cd98165face0e42a33a5173)
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 #include <sys/ctype.h>
59 
60 #ifdef DDB
61 #include <ddb/ddb.h>
62 #endif
63 
64 /*
65  * Note that stdarg.h and the ANSI style va_start macro is used for both
66  * ANSI and traditional C compilers.
67  */
68 #include <machine/stdarg.h>
69 
70 #define TOCONS	0x01
71 #define TOTTY	0x02
72 #define TOLOG	0x04
73 
74 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
75 #define MAXNBUF	(sizeof(intmax_t) * NBBY + 1)
76 
77 struct putchar_arg {
78 	int	flags;
79 	int	pri;
80 	struct	tty *tty;
81 };
82 
83 struct snprintf_arg {
84 	char	*str;
85 	size_t	remain;
86 };
87 
88 extern	int log_open;
89 
90 static void  msglogchar(int c, int pri);
91 static void  putchar(int ch, void *arg);
92 static char *ksprintn(char *nbuf, uintmax_t num, int base, int *len, int upper);
93 static void  snprintf_func(int ch, void *arg);
94 
95 static int consintr = 1;		/* Ok to handle console interrupts? */
96 static int msgbufmapped;		/* Set when safe to use msgbuf */
97 int msgbuftrigger;
98 
99 static int      log_console_output = 1;
100 TUNABLE_INT("kern.log_console_output", &log_console_output);
101 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
102     &log_console_output, 0, "Duplicate console output to the syslog.");
103 
104 static int	always_console_output = 0;
105 TUNABLE_INT("kern.always_console_output", &always_console_output);
106 SYSCTL_INT(_kern, OID_AUTO, always_console_output, CTLFLAG_RW,
107     &always_console_output, 0, "Always output to console despite TIOCCONS.");
108 
109 /*
110  * Warn that a system table is full.
111  */
112 void
113 tablefull(const char *tab)
114 {
115 
116 	log(LOG_ERR, "%s: table is full\n", tab);
117 }
118 
119 /*
120  * Uprintf prints to the controlling terminal for the current process.
121  */
122 int
123 uprintf(const char *fmt, ...)
124 {
125 	struct thread *td = curthread;
126 	struct proc *p = td->td_proc;
127 	va_list ap;
128 	struct putchar_arg pca;
129 	int retval;
130 
131 	if (td == NULL || td == PCPU_GET(idlethread))
132 		return (0);
133 
134 	mtx_lock(&Giant);
135 	p = td->td_proc;
136 	PROC_LOCK(p);
137 	if ((p->p_flag & P_CONTROLT) == 0) {
138 		PROC_UNLOCK(p);
139 		retval = 0;
140 		goto out;
141 	}
142 	SESS_LOCK(p->p_session);
143 	pca.tty = p->p_session->s_ttyp;
144 	SESS_UNLOCK(p->p_session);
145 	PROC_UNLOCK(p);
146 	if (pca.tty == NULL) {
147 		retval = 0;
148 		goto out;
149 	}
150 	pca.flags = TOTTY;
151 	va_start(ap, fmt);
152 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
153 	va_end(ap);
154 out:
155 	mtx_unlock(&Giant);
156 	return (retval);
157 }
158 
159 /*
160  * tprintf prints on the controlling terminal associated with the given
161  * 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 	mtx_lock(&Giant);
173 	if (pri != -1)
174 		flags |= TOLOG;
175 	if (p != NULL) {
176 		PROC_LOCK(p);
177 		if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
178 			sess = p->p_session;
179 			SESS_LOCK(sess);
180 			PROC_UNLOCK(p);
181 			SESSHOLD(sess);
182 			tp = sess->s_ttyp;
183 			SESS_UNLOCK(sess);
184 			if (ttycheckoutq(tp, 0))
185 				flags |= TOTTY;
186 			else
187 				tp = NULL;
188 		} else
189 			PROC_UNLOCK(p);
190 	}
191 	pca.pri = pri;
192 	pca.tty = tp;
193 	pca.flags = flags;
194 	va_start(ap, fmt);
195 	kvprintf(fmt, putchar, &pca, 10, ap);
196 	va_end(ap);
197 	if (sess != NULL)
198 		SESSRELE(sess);
199 	msgbuftrigger = 1;
200 	mtx_unlock(&Giant);
201 }
202 
203 /*
204  * Ttyprintf displays a message on a tty; it should be used only by
205  * the tty driver, or anything that knows the underlying tty will not
206  * be revoke(2)'d away.  Other callers should use tprintf.
207  */
208 int
209 ttyprintf(struct tty *tp, const char *fmt, ...)
210 {
211 	va_list ap;
212 	struct putchar_arg pca;
213 	int retval;
214 
215 	va_start(ap, fmt);
216 	pca.tty = tp;
217 	pca.flags = TOTTY;
218 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
219 	va_end(ap);
220 	return (retval);
221 }
222 
223 /*
224  * Log writes to the log buffer, and guarantees not to sleep (so can be
225  * called by interrupt routines).  If there is no process reading the
226  * log yet, it writes to the console also.
227  */
228 void
229 log(int level, const char *fmt, ...)
230 {
231 	va_list ap;
232 	struct putchar_arg pca;
233 
234 	pca.tty = NULL;
235 	pca.pri = level;
236 	pca.flags = log_open ? TOLOG : TOCONS;
237 
238 	va_start(ap, fmt);
239 	kvprintf(fmt, putchar, &pca, 10, ap);
240 	va_end(ap);
241 
242 	msgbuftrigger = 1;
243 }
244 
245 #define CONSCHUNK 128
246 
247 void
248 log_console(struct uio *uio)
249 {
250 	int c, i, error, nl;
251 	char *consbuffer;
252 	int pri;
253 
254 	if (!log_console_output)
255 		return;
256 
257 	pri = LOG_INFO | LOG_CONSOLE;
258 	uio = cloneuio(uio);
259 	consbuffer = malloc(CONSCHUNK, M_TEMP, M_WAITOK);
260 
261 	nl = 0;
262 	while (uio->uio_resid > 0) {
263 		c = imin(uio->uio_resid, CONSCHUNK);
264 		error = uiomove(consbuffer, c, uio);
265 		if (error != 0)
266 			break;
267 		for (i = 0; i < c; i++) {
268 			msglogchar(consbuffer[i], pri);
269 			if (consbuffer[i] == '\n')
270 				nl = 1;
271 			else
272 				nl = 0;
273 		}
274 	}
275 	if (!nl)
276 		msglogchar('\n', pri);
277 	msgbuftrigger = 1;
278 	free(uio, M_IOV);
279 	free(consbuffer, M_TEMP);
280 	return;
281 }
282 
283 int
284 printf(const char *fmt, ...)
285 {
286 	va_list ap;
287 	int savintr;
288 	struct putchar_arg pca;
289 	int retval;
290 
291 	savintr = consintr;		/* disable interrupts */
292 	consintr = 0;
293 	va_start(ap, fmt);
294 	pca.tty = NULL;
295 	pca.flags = TOCONS | TOLOG;
296 	pca.pri = -1;
297 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
298 	va_end(ap);
299 	if (!panicstr)
300 		msgbuftrigger = 1;
301 	consintr = savintr;		/* reenable interrupts */
302 	return (retval);
303 }
304 
305 int
306 vprintf(const char *fmt, va_list ap)
307 {
308 	int savintr;
309 	struct putchar_arg pca;
310 	int retval;
311 
312 	savintr = consintr;		/* disable interrupts */
313 	consintr = 0;
314 	pca.tty = NULL;
315 	pca.flags = TOCONS | TOLOG;
316 	pca.pri = -1;
317 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
318 	if (!panicstr)
319 		msgbuftrigger = 1;
320 	consintr = savintr;		/* reenable interrupts */
321 	return (retval);
322 }
323 
324 /*
325  * Print a character on console or users terminal.  If destination is
326  * the console then the last bunch of characters are saved in msgbuf for
327  * inspection later.
328  */
329 static void
330 putchar(int c, void *arg)
331 {
332 	struct putchar_arg *ap = (struct putchar_arg*) arg;
333 	struct tty *tp = ap->tty;
334 	int consdirect, flags = ap->flags;
335 
336 	consdirect = ((flags & TOCONS) && constty == NULL);
337 	/* Don't use the tty code after a panic or while in ddb. */
338 	if (panicstr)
339 		consdirect = 1;
340 	if (kdb_active)
341 		consdirect = 1;
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) {
349 			if (constty != NULL)
350 				msgbuf_addchar(&consmsgbuf, c);
351 			if (always_console_output && c != '\0')
352 				cnputc(c);
353 		}
354 	}
355 	if ((flags & TOLOG))
356 		msglogchar(c, ap->pri);
357 }
358 
359 /*
360  * Scaled down version of sprintf(3).
361  */
362 int
363 sprintf(char *buf, const char *cfmt, ...)
364 {
365 	int retval;
366 	va_list ap;
367 
368 	va_start(ap, cfmt);
369 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
370 	buf[retval] = '\0';
371 	va_end(ap);
372 	return (retval);
373 }
374 
375 /*
376  * Scaled down version of vsprintf(3).
377  */
378 int
379 vsprintf(char *buf, const char *cfmt, va_list ap)
380 {
381 	int retval;
382 
383 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
384 	buf[retval] = '\0';
385 	return (retval);
386 }
387 
388 /*
389  * Scaled down version of snprintf(3).
390  */
391 int
392 snprintf(char *str, size_t size, const char *format, ...)
393 {
394 	int retval;
395 	va_list ap;
396 
397 	va_start(ap, format);
398 	retval = vsnprintf(str, size, format, ap);
399 	va_end(ap);
400 	return(retval);
401 }
402 
403 /*
404  * Scaled down version of vsnprintf(3).
405  */
406 int
407 vsnprintf(char *str, size_t size, const char *format, va_list ap)
408 {
409 	struct snprintf_arg info;
410 	int retval;
411 
412 	info.str = str;
413 	info.remain = size;
414 	retval = kvprintf(format, snprintf_func, &info, 10, ap);
415 	if (info.remain >= 1)
416 		*info.str++ = '\0';
417 	return (retval);
418 }
419 
420 /*
421  * Kernel version which takes radix argument vsnprintf(3).
422  */
423 int
424 vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
425 {
426 	struct snprintf_arg info;
427 	int retval;
428 
429 	info.str = str;
430 	info.remain = size;
431 	retval = kvprintf(format, snprintf_func, &info, radix, ap);
432 	if (info.remain >= 1)
433 		*info.str++ = '\0';
434 	return (retval);
435 }
436 
437 static void
438 snprintf_func(int ch, void *arg)
439 {
440 	struct snprintf_arg *const info = arg;
441 
442 	if (info->remain >= 2) {
443 		*info->str++ = ch;
444 		info->remain--;
445 	}
446 }
447 
448 /*
449  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
450  * order; return an optional length and a pointer to the last character
451  * written in the buffer (i.e., the first character of the string).
452  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
453  */
454 static char *
455 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
456 {
457 	char *p, c;
458 
459 	p = nbuf;
460 	*p = '\0';
461 	do {
462 		c = hex2ascii(num % base);
463 		*++p = upper ? toupper(c) : c;
464 	} while (num /= base);
465 	if (lenp)
466 		*lenp = p - nbuf;
467 	return (p);
468 }
469 
470 /*
471  * Scaled down version of printf(3).
472  *
473  * Two additional formats:
474  *
475  * The format %b is supported to decode error registers.
476  * Its usage is:
477  *
478  *	printf("reg=%b\n", regval, "<base><arg>*");
479  *
480  * where <base> is the output base expressed as a control character, e.g.
481  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
482  * the first of which gives the bit number to be inspected (origin 1), and
483  * the next characters (up to a control character, i.e. a character <= 32),
484  * give the name of the register.  Thus:
485  *
486  *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
487  *
488  * would produce output:
489  *
490  *	reg=3<BITTWO,BITONE>
491  *
492  * XXX:  %D  -- Hexdump, takes pointer and separator string:
493  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
494  *		("%*D", len, ptr, " " -> XX XX XX XX ...
495  */
496 int
497 kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
498 {
499 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
500 	char nbuf[MAXNBUF];
501 	char *d;
502 	const char *p, *percent, *q;
503 	u_char *up;
504 	int ch, n;
505 	uintmax_t num;
506 	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
507 	int cflag, hflag, jflag, tflag, zflag;
508 	int dwidth, upper;
509 	char padc;
510 	int stop = 0, retval = 0;
511 
512 	num = 0;
513 	if (!func)
514 		d = (char *) arg;
515 	else
516 		d = NULL;
517 
518 	if (fmt == NULL)
519 		fmt = "(fmt null)\n";
520 
521 	if (radix < 2 || radix > 36)
522 		radix = 10;
523 
524 	for (;;) {
525 		padc = ' ';
526 		width = 0;
527 		while ((ch = (u_char)*fmt++) != '%' || stop) {
528 			if (ch == '\0')
529 				return (retval);
530 			PCHAR(ch);
531 		}
532 		percent = fmt - 1;
533 		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
534 		sign = 0; dot = 0; dwidth = 0; upper = 0;
535 		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
536 reswitch:	switch (ch = (u_char)*fmt++) {
537 		case '.':
538 			dot = 1;
539 			goto reswitch;
540 		case '#':
541 			sharpflag = 1;
542 			goto reswitch;
543 		case '+':
544 			sign = 1;
545 			goto reswitch;
546 		case '-':
547 			ladjust = 1;
548 			goto reswitch;
549 		case '%':
550 			PCHAR(ch);
551 			break;
552 		case '*':
553 			if (!dot) {
554 				width = va_arg(ap, int);
555 				if (width < 0) {
556 					ladjust = !ladjust;
557 					width = -width;
558 				}
559 			} else {
560 				dwidth = va_arg(ap, int);
561 			}
562 			goto reswitch;
563 		case '0':
564 			if (!dot) {
565 				padc = '0';
566 				goto reswitch;
567 			}
568 		case '1': case '2': case '3': case '4':
569 		case '5': case '6': case '7': case '8': case '9':
570 				for (n = 0;; ++fmt) {
571 					n = n * 10 + ch - '0';
572 					ch = *fmt;
573 					if (ch < '0' || ch > '9')
574 						break;
575 				}
576 			if (dot)
577 				dwidth = n;
578 			else
579 				width = n;
580 			goto reswitch;
581 		case 'b':
582 			num = (u_int)va_arg(ap, int);
583 			p = va_arg(ap, char *);
584 			for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
585 				PCHAR(*q--);
586 
587 			if (num == 0)
588 				break;
589 
590 			for (tmp = 0; *p;) {
591 				n = *p++;
592 				if (num & (1 << (n - 1))) {
593 					PCHAR(tmp ? ',' : '<');
594 					for (; (n = *p) > ' '; ++p)
595 						PCHAR(n);
596 					tmp = 1;
597 				} else
598 					for (; *p > ' '; ++p)
599 						continue;
600 			}
601 			if (tmp)
602 				PCHAR('>');
603 			break;
604 		case 'c':
605 			PCHAR(va_arg(ap, int));
606 			break;
607 		case 'D':
608 			up = va_arg(ap, u_char *);
609 			p = va_arg(ap, char *);
610 			if (!width)
611 				width = 16;
612 			while(width--) {
613 				PCHAR(hex2ascii(*up >> 4));
614 				PCHAR(hex2ascii(*up & 0x0f));
615 				up++;
616 				if (width)
617 					for (q=p;*q;q++)
618 						PCHAR(*q);
619 			}
620 			break;
621 		case 'd':
622 		case 'i':
623 			base = 10;
624 			sign = 1;
625 			goto handle_sign;
626 		case 'h':
627 			if (hflag) {
628 				hflag = 0;
629 				cflag = 1;
630 			} else
631 				hflag = 1;
632 			goto reswitch;
633 		case 'j':
634 			jflag = 1;
635 			goto reswitch;
636 		case 'l':
637 			if (lflag) {
638 				lflag = 0;
639 				qflag = 1;
640 			} else
641 				lflag = 1;
642 			goto reswitch;
643 		case 'n':
644 			if (jflag)
645 				*(va_arg(ap, intmax_t *)) = retval;
646 			else if (qflag)
647 				*(va_arg(ap, quad_t *)) = retval;
648 			else if (lflag)
649 				*(va_arg(ap, long *)) = retval;
650 			else if (zflag)
651 				*(va_arg(ap, size_t *)) = retval;
652 			else if (hflag)
653 				*(va_arg(ap, short *)) = retval;
654 			else if (cflag)
655 				*(va_arg(ap, char *)) = retval;
656 			else
657 				*(va_arg(ap, int *)) = retval;
658 			break;
659 		case 'o':
660 			base = 8;
661 			goto handle_nosign;
662 		case 'p':
663 			base = 16;
664 			sharpflag = (width == 0);
665 			sign = 0;
666 			num = (uintptr_t)va_arg(ap, void *);
667 			goto number;
668 		case 'q':
669 			qflag = 1;
670 			goto reswitch;
671 		case 'r':
672 			base = radix;
673 			if (sign)
674 				goto handle_sign;
675 			goto handle_nosign;
676 		case 's':
677 			p = va_arg(ap, char *);
678 			if (p == NULL)
679 				p = "(null)";
680 			if (!dot)
681 				n = strlen (p);
682 			else
683 				for (n = 0; n < dwidth && p[n]; n++)
684 					continue;
685 
686 			width -= n;
687 
688 			if (!ladjust && width > 0)
689 				while (width--)
690 					PCHAR(padc);
691 			while (n--)
692 				PCHAR(*p++);
693 			if (ladjust && width > 0)
694 				while (width--)
695 					PCHAR(padc);
696 			break;
697 		case 't':
698 			tflag = 1;
699 			goto reswitch;
700 		case 'u':
701 			base = 10;
702 			goto handle_nosign;
703 		case 'X':
704 			upper = 1;
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, upper);
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, 0); *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;
916 
917 	if (!msgbufmapped) {
918 		db_printf("msgbuf not mapped yet\n");
919 		return;
920 	}
921 	db_printf("msgbufp = %p\n", msgbufp);
922 	db_printf("magic = %x, size = %d, r= %u, w = %u, ptr = %p, cksum= %u\n",
923 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_rseq,
924 	    msgbufp->msg_wseq, msgbufp->msg_ptr, msgbufp->msg_cksum);
925 	for (i = 0; i < msgbufp->msg_size && !db_pager_quit; i++) {
926 		j = MSGBUF_SEQ_TO_POS(msgbufp, i + msgbufp->msg_rseq);
927 		db_printf("%c", msgbufp->msg_ptr[j]);
928 	}
929 	db_printf("\n");
930 }
931 
932 #endif /* DDB */
933 
934 void
935 hexdump(const void *ptr, int length, const char *hdr, int flags)
936 {
937 	int i, j, k;
938 	int cols;
939 	const unsigned char *cp;
940 	char delim;
941 
942 	if ((flags & HD_DELIM_MASK) != 0)
943 		delim = (flags & HD_DELIM_MASK) >> 8;
944 	else
945 		delim = ' ';
946 
947 	if ((flags & HD_COLUMN_MASK) != 0)
948 		cols = flags & HD_COLUMN_MASK;
949 	else
950 		cols = 16;
951 
952 	cp = ptr;
953 	for (i = 0; i < length; i+= cols) {
954 		if (hdr != NULL)
955 			printf("%s", hdr);
956 
957 		if ((flags & HD_OMIT_COUNT) == 0)
958 			printf("%04x  ", i);
959 
960 		if ((flags & HD_OMIT_HEX) == 0) {
961 			for (j = 0; j < cols; j++) {
962 				k = i + j;
963 				if (k < length)
964 					printf("%c%02x", delim, cp[k]);
965 				else
966 					printf("   ");
967 			}
968 		}
969 
970 		if ((flags & HD_OMIT_CHARS) == 0) {
971 			printf("  |");
972 			for (j = 0; j < cols; j++) {
973 				k = i + j;
974 				if (k >= length)
975 					printf(" ");
976 				else if (cp[k] >= ' ' && cp[k] <= '~')
977 					printf("%c", cp[k]);
978 				else
979 					printf(".");
980 			}
981 			printf("|");
982 		}
983 		printf("\n");
984 	}
985 }
986 
987