xref: /freebsd/sys/kern/subr_prf.c (revision 262e143bd46171a6415a5b28af260a5efa2a3db8)
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  */
121 int
122 uprintf(const char *fmt, ...)
123 {
124 	struct thread *td = curthread;
125 	struct proc *p = td->td_proc;
126 	va_list ap;
127 	struct putchar_arg pca;
128 	int retval;
129 
130 	if (td == NULL || td == PCPU_GET(idlethread))
131 		return (0);
132 
133 	mtx_lock(&Giant);
134 	p = td->td_proc;
135 	PROC_LOCK(p);
136 	if ((p->p_flag & P_CONTROLT) == 0) {
137 		PROC_UNLOCK(p);
138 		retval = 0;
139 		goto out;
140 	}
141 	SESS_LOCK(p->p_session);
142 	pca.tty = p->p_session->s_ttyp;
143 	SESS_UNLOCK(p->p_session);
144 	PROC_UNLOCK(p);
145 	if (pca.tty == NULL) {
146 		retval = 0;
147 		goto out;
148 	}
149 	pca.flags = TOTTY;
150 	va_start(ap, fmt);
151 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
152 	va_end(ap);
153 out:
154 	mtx_unlock(&Giant);
155 	return (retval);
156 }
157 
158 /*
159  * tprintf prints on the controlling terminal associated with the given
160  * session, possibly to the log as well.
161  */
162 void
163 tprintf(struct proc *p, int pri, const char *fmt, ...)
164 {
165 	struct tty *tp = NULL;
166 	int flags = 0;
167 	va_list ap;
168 	struct putchar_arg pca;
169 	struct session *sess = NULL;
170 
171 	mtx_lock(&Giant);
172 	if (pri != -1)
173 		flags |= TOLOG;
174 	if (p != NULL) {
175 		PROC_LOCK(p);
176 		if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
177 			sess = p->p_session;
178 			SESS_LOCK(sess);
179 			PROC_UNLOCK(p);
180 			SESSHOLD(sess);
181 			tp = sess->s_ttyp;
182 			SESS_UNLOCK(sess);
183 			if (ttycheckoutq(tp, 0))
184 				flags |= TOTTY;
185 			else
186 				tp = NULL;
187 		} else
188 			PROC_UNLOCK(p);
189 	}
190 	pca.pri = pri;
191 	pca.tty = tp;
192 	pca.flags = flags;
193 	va_start(ap, fmt);
194 	kvprintf(fmt, putchar, &pca, 10, ap);
195 	va_end(ap);
196 	if (sess != NULL)
197 		SESSRELE(sess);
198 	msgbuftrigger = 1;
199 	mtx_unlock(&Giant);
200 }
201 
202 /*
203  * Ttyprintf displays a message on a tty; it should be used only by
204  * the tty driver, or anything that knows the underlying tty will not
205  * be revoke(2)'d away.  Other callers should use tprintf.
206  */
207 int
208 ttyprintf(struct tty *tp, const char *fmt, ...)
209 {
210 	va_list ap;
211 	struct putchar_arg pca;
212 	int retval;
213 
214 	va_start(ap, fmt);
215 	pca.tty = tp;
216 	pca.flags = TOTTY;
217 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
218 	va_end(ap);
219 	return (retval);
220 }
221 
222 /*
223  * Log writes to the log buffer, and guarantees not to sleep (so can be
224  * called by interrupt routines).  If there is no process reading the
225  * log yet, it writes to the console also.
226  */
227 void
228 log(int level, const char *fmt, ...)
229 {
230 	va_list ap;
231 	struct putchar_arg pca;
232 
233 	pca.tty = NULL;
234 	pca.pri = level;
235 	pca.flags = log_open ? TOLOG : TOCONS;
236 
237 	va_start(ap, fmt);
238 	kvprintf(fmt, putchar, &pca, 10, ap);
239 	va_end(ap);
240 
241 	msgbuftrigger = 1;
242 }
243 
244 #define CONSCHUNK 128
245 
246 void
247 log_console(struct uio *uio)
248 {
249 	int c, i, error, nl;
250 	char *consbuffer;
251 	int pri;
252 
253 	if (!log_console_output)
254 		return;
255 
256 	pri = LOG_INFO | LOG_CONSOLE;
257 	uio = cloneuio(uio);
258 	consbuffer = malloc(CONSCHUNK, M_TEMP, M_WAITOK);
259 
260 	nl = 0;
261 	while (uio->uio_resid > 0) {
262 		c = imin(uio->uio_resid, CONSCHUNK);
263 		error = uiomove(consbuffer, c, uio);
264 		if (error != 0)
265 			break;
266 		for (i = 0; i < c; i++) {
267 			msglogchar(consbuffer[i], pri);
268 			if (consbuffer[i] == '\n')
269 				nl = 1;
270 			else
271 				nl = 0;
272 		}
273 	}
274 	if (!nl)
275 		msglogchar('\n', pri);
276 	msgbuftrigger = 1;
277 	free(uio, M_IOV);
278 	free(consbuffer, M_TEMP);
279 	return;
280 }
281 
282 int
283 printf(const char *fmt, ...)
284 {
285 	va_list ap;
286 	int savintr;
287 	struct putchar_arg pca;
288 	int retval;
289 
290 	savintr = consintr;		/* disable interrupts */
291 	consintr = 0;
292 	va_start(ap, fmt);
293 	pca.tty = NULL;
294 	pca.flags = TOCONS | TOLOG;
295 	pca.pri = -1;
296 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
297 	va_end(ap);
298 	if (!panicstr)
299 		msgbuftrigger = 1;
300 	consintr = savintr;		/* reenable interrupts */
301 	return (retval);
302 }
303 
304 int
305 vprintf(const char *fmt, va_list ap)
306 {
307 	int savintr;
308 	struct putchar_arg pca;
309 	int retval;
310 
311 	savintr = consintr;		/* disable interrupts */
312 	consintr = 0;
313 	pca.tty = NULL;
314 	pca.flags = TOCONS | TOLOG;
315 	pca.pri = -1;
316 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
317 	if (!panicstr)
318 		msgbuftrigger = 1;
319 	consintr = savintr;		/* reenable interrupts */
320 	return (retval);
321 }
322 
323 /*
324  * Print a character on console or users terminal.  If destination is
325  * the console then the last bunch of characters are saved in msgbuf for
326  * inspection later.
327  */
328 static void
329 putchar(int c, void *arg)
330 {
331 	struct putchar_arg *ap = (struct putchar_arg*) arg;
332 	struct tty *tp = ap->tty;
333 	int consdirect, flags = ap->flags;
334 
335 	consdirect = ((flags & TOCONS) && constty == NULL);
336 	/* Don't use the tty code after a panic or while in ddb. */
337 	if (panicstr)
338 		consdirect = 1;
339 	if (kdb_active)
340 		consdirect = 1;
341 	if (consdirect) {
342 		if (c != '\0')
343 			cnputc(c);
344 	} else {
345 		if ((flags & TOTTY) && tp != NULL)
346 			tputchar(c, tp);
347 		if (flags & TOCONS) {
348 			if (constty != NULL)
349 				msgbuf_addchar(&consmsgbuf, c);
350 			if (always_console_output && c != '\0')
351 				cnputc(c);
352 		}
353 	}
354 	if ((flags & TOLOG))
355 		msglogchar(c, ap->pri);
356 }
357 
358 /*
359  * Scaled down version of sprintf(3).
360  */
361 int
362 sprintf(char *buf, const char *cfmt, ...)
363 {
364 	int retval;
365 	va_list ap;
366 
367 	va_start(ap, cfmt);
368 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
369 	buf[retval] = '\0';
370 	va_end(ap);
371 	return (retval);
372 }
373 
374 /*
375  * Scaled down version of vsprintf(3).
376  */
377 int
378 vsprintf(char *buf, const char *cfmt, va_list ap)
379 {
380 	int retval;
381 
382 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
383 	buf[retval] = '\0';
384 	return (retval);
385 }
386 
387 /*
388  * Scaled down version of snprintf(3).
389  */
390 int
391 snprintf(char *str, size_t size, const char *format, ...)
392 {
393 	int retval;
394 	va_list ap;
395 
396 	va_start(ap, format);
397 	retval = vsnprintf(str, size, format, ap);
398 	va_end(ap);
399 	return(retval);
400 }
401 
402 /*
403  * Scaled down version of vsnprintf(3).
404  */
405 int
406 vsnprintf(char *str, size_t size, const char *format, va_list ap)
407 {
408 	struct snprintf_arg info;
409 	int retval;
410 
411 	info.str = str;
412 	info.remain = size;
413 	retval = kvprintf(format, snprintf_func, &info, 10, ap);
414 	if (info.remain >= 1)
415 		*info.str++ = '\0';
416 	return (retval);
417 }
418 
419 /*
420  * Kernel version which takes radix argument vsnprintf(3).
421  */
422 int
423 vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
424 {
425 	struct snprintf_arg info;
426 	int retval;
427 
428 	info.str = str;
429 	info.remain = size;
430 	retval = kvprintf(format, snprintf_func, &info, radix, ap);
431 	if (info.remain >= 1)
432 		*info.str++ = '\0';
433 	return (retval);
434 }
435 
436 static void
437 snprintf_func(int ch, void *arg)
438 {
439 	struct snprintf_arg *const info = arg;
440 
441 	if (info->remain >= 2) {
442 		*info->str++ = ch;
443 		info->remain--;
444 	}
445 }
446 
447 /*
448  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
449  * order; return an optional length and a pointer to the last character
450  * written in the buffer (i.e., the first character of the string).
451  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
452  */
453 static char *
454 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp)
455 {
456 	char *p;
457 
458 	p = nbuf;
459 	*p = '\0';
460 	do {
461 		*++p = hex2ascii(num % base);
462 	} while (num /= base);
463 	if (lenp)
464 		*lenp = p - nbuf;
465 	return (p);
466 }
467 
468 /*
469  * Scaled down version of printf(3).
470  *
471  * Two additional formats:
472  *
473  * The format %b is supported to decode error registers.
474  * Its usage is:
475  *
476  *	printf("reg=%b\n", regval, "<base><arg>*");
477  *
478  * where <base> is the output base expressed as a control character, e.g.
479  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
480  * the first of which gives the bit number to be inspected (origin 1), and
481  * the next characters (up to a control character, i.e. a character <= 32),
482  * give the name of the register.  Thus:
483  *
484  *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
485  *
486  * would produce output:
487  *
488  *	reg=3<BITTWO,BITONE>
489  *
490  * XXX:  %D  -- Hexdump, takes pointer and separator string:
491  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
492  *		("%*D", len, ptr, " " -> XX XX XX XX ...
493  */
494 int
495 kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
496 {
497 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
498 	char nbuf[MAXNBUF];
499 	char *d;
500 	const char *p, *percent, *q;
501 	u_char *up;
502 	int ch, n;
503 	uintmax_t num;
504 	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
505 	int cflag, hflag, jflag, tflag, zflag;
506 	int dwidth;
507 	char padc;
508 	int stop = 0, retval = 0;
509 
510 	num = 0;
511 	if (!func)
512 		d = (char *) arg;
513 	else
514 		d = NULL;
515 
516 	if (fmt == NULL)
517 		fmt = "(fmt null)\n";
518 
519 	if (radix < 2 || radix > 36)
520 		radix = 10;
521 
522 	for (;;) {
523 		padc = ' ';
524 		width = 0;
525 		while ((ch = (u_char)*fmt++) != '%' || stop) {
526 			if (ch == '\0')
527 				return (retval);
528 			PCHAR(ch);
529 		}
530 		percent = fmt - 1;
531 		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
532 		sign = 0; dot = 0; dwidth = 0;
533 		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
534 reswitch:	switch (ch = (u_char)*fmt++) {
535 		case '.':
536 			dot = 1;
537 			goto reswitch;
538 		case '#':
539 			sharpflag = 1;
540 			goto reswitch;
541 		case '+':
542 			sign = 1;
543 			goto reswitch;
544 		case '-':
545 			ladjust = 1;
546 			goto reswitch;
547 		case '%':
548 			PCHAR(ch);
549 			break;
550 		case '*':
551 			if (!dot) {
552 				width = va_arg(ap, int);
553 				if (width < 0) {
554 					ladjust = !ladjust;
555 					width = -width;
556 				}
557 			} else {
558 				dwidth = va_arg(ap, int);
559 			}
560 			goto reswitch;
561 		case '0':
562 			if (!dot) {
563 				padc = '0';
564 				goto reswitch;
565 			}
566 		case '1': case '2': case '3': case '4':
567 		case '5': case '6': case '7': case '8': case '9':
568 				for (n = 0;; ++fmt) {
569 					n = n * 10 + ch - '0';
570 					ch = *fmt;
571 					if (ch < '0' || ch > '9')
572 						break;
573 				}
574 			if (dot)
575 				dwidth = n;
576 			else
577 				width = n;
578 			goto reswitch;
579 		case 'b':
580 			num = (u_int)va_arg(ap, int);
581 			p = va_arg(ap, char *);
582 			for (q = ksprintn(nbuf, num, *p++, NULL); *q;)
583 				PCHAR(*q--);
584 
585 			if (num == 0)
586 				break;
587 
588 			for (tmp = 0; *p;) {
589 				n = *p++;
590 				if (num & (1 << (n - 1))) {
591 					PCHAR(tmp ? ',' : '<');
592 					for (; (n = *p) > ' '; ++p)
593 						PCHAR(n);
594 					tmp = 1;
595 				} else
596 					for (; *p > ' '; ++p)
597 						continue;
598 			}
599 			if (tmp)
600 				PCHAR('>');
601 			break;
602 		case 'c':
603 			PCHAR(va_arg(ap, int));
604 			break;
605 		case 'D':
606 			up = va_arg(ap, u_char *);
607 			p = va_arg(ap, char *);
608 			if (!width)
609 				width = 16;
610 			while(width--) {
611 				PCHAR(hex2ascii(*up >> 4));
612 				PCHAR(hex2ascii(*up & 0x0f));
613 				up++;
614 				if (width)
615 					for (q=p;*q;q++)
616 						PCHAR(*q);
617 			}
618 			break;
619 		case 'd':
620 		case 'i':
621 			base = 10;
622 			sign = 1;
623 			goto handle_sign;
624 		case 'h':
625 			if (hflag) {
626 				hflag = 0;
627 				cflag = 1;
628 			} else
629 				hflag = 1;
630 			goto reswitch;
631 		case 'j':
632 			jflag = 1;
633 			goto reswitch;
634 		case 'l':
635 			if (lflag) {
636 				lflag = 0;
637 				qflag = 1;
638 			} else
639 				lflag = 1;
640 			goto reswitch;
641 		case 'n':
642 			if (jflag)
643 				*(va_arg(ap, intmax_t *)) = retval;
644 			else if (qflag)
645 				*(va_arg(ap, quad_t *)) = retval;
646 			else if (lflag)
647 				*(va_arg(ap, long *)) = retval;
648 			else if (zflag)
649 				*(va_arg(ap, size_t *)) = retval;
650 			else if (hflag)
651 				*(va_arg(ap, short *)) = retval;
652 			else if (cflag)
653 				*(va_arg(ap, char *)) = retval;
654 			else
655 				*(va_arg(ap, int *)) = retval;
656 			break;
657 		case 'o':
658 			base = 8;
659 			goto handle_nosign;
660 		case 'p':
661 			base = 16;
662 			sharpflag = (width == 0);
663 			sign = 0;
664 			num = (uintptr_t)va_arg(ap, void *);
665 			goto number;
666 		case 'q':
667 			qflag = 1;
668 			goto reswitch;
669 		case 'r':
670 			base = radix;
671 			if (sign)
672 				goto handle_sign;
673 			goto handle_nosign;
674 		case 's':
675 			p = va_arg(ap, char *);
676 			if (p == NULL)
677 				p = "(null)";
678 			if (!dot)
679 				n = strlen (p);
680 			else
681 				for (n = 0; n < dwidth && p[n]; n++)
682 					continue;
683 
684 			width -= n;
685 
686 			if (!ladjust && width > 0)
687 				while (width--)
688 					PCHAR(padc);
689 			while (n--)
690 				PCHAR(*p++);
691 			if (ladjust && width > 0)
692 				while (width--)
693 					PCHAR(padc);
694 			break;
695 		case 't':
696 			tflag = 1;
697 			goto reswitch;
698 		case 'u':
699 			base = 10;
700 			goto handle_nosign;
701 		case 'x':
702 		case 'X':
703 			base = 16;
704 			goto handle_nosign;
705 		case 'y':
706 			base = 16;
707 			sign = 1;
708 			goto handle_sign;
709 		case 'z':
710 			zflag = 1;
711 			goto reswitch;
712 handle_nosign:
713 			sign = 0;
714 			if (jflag)
715 				num = va_arg(ap, uintmax_t);
716 			else if (qflag)
717 				num = va_arg(ap, u_quad_t);
718 			else if (tflag)
719 				num = va_arg(ap, ptrdiff_t);
720 			else if (lflag)
721 				num = va_arg(ap, u_long);
722 			else if (zflag)
723 				num = va_arg(ap, size_t);
724 			else if (hflag)
725 				num = (u_short)va_arg(ap, int);
726 			else if (cflag)
727 				num = (u_char)va_arg(ap, int);
728 			else
729 				num = va_arg(ap, u_int);
730 			goto number;
731 handle_sign:
732 			if (jflag)
733 				num = va_arg(ap, intmax_t);
734 			else if (qflag)
735 				num = va_arg(ap, quad_t);
736 			else if (tflag)
737 				num = va_arg(ap, ptrdiff_t);
738 			else if (lflag)
739 				num = va_arg(ap, long);
740 			else if (zflag)
741 				num = va_arg(ap, size_t);
742 			else if (hflag)
743 				num = (short)va_arg(ap, int);
744 			else if (cflag)
745 				num = (char)va_arg(ap, int);
746 			else
747 				num = va_arg(ap, int);
748 number:
749 			if (sign && (intmax_t)num < 0) {
750 				neg = 1;
751 				num = -(intmax_t)num;
752 			}
753 			p = ksprintn(nbuf, num, base, &tmp);
754 			if (sharpflag && num != 0) {
755 				if (base == 8)
756 					tmp++;
757 				else if (base == 16)
758 					tmp += 2;
759 			}
760 			if (neg)
761 				tmp++;
762 
763 			if (!ladjust && padc != '0' && width
764 			    && (width -= tmp) > 0)
765 				while (width--)
766 					PCHAR(padc);
767 			if (neg)
768 				PCHAR('-');
769 			if (sharpflag && num != 0) {
770 				if (base == 8) {
771 					PCHAR('0');
772 				} else if (base == 16) {
773 					PCHAR('0');
774 					PCHAR('x');
775 				}
776 			}
777 			if (!ladjust && width && (width -= tmp) > 0)
778 				while (width--)
779 					PCHAR(padc);
780 
781 			while (*p)
782 				PCHAR(*p--);
783 
784 			if (ladjust && width && (width -= tmp) > 0)
785 				while (width--)
786 					PCHAR(padc);
787 
788 			break;
789 		default:
790 			while (percent < fmt)
791 				PCHAR(*percent++);
792 			/*
793 			 * Since we ignore an formatting argument it is no
794 			 * longer safe to obey the remaining formatting
795 			 * arguments as the arguments will no longer match
796 			 * the format specs.
797 			 */
798 			stop = 1;
799 			break;
800 		}
801 	}
802 #undef PCHAR
803 }
804 
805 /*
806  * Put character in log buffer with a particular priority.
807  */
808 static void
809 msglogchar(int c, int pri)
810 {
811 	static int lastpri = -1;
812 	static int dangling;
813 	char nbuf[MAXNBUF];
814 	char *p;
815 
816 	if (!msgbufmapped)
817 		return;
818 	if (c == '\0' || c == '\r')
819 		return;
820 	if (pri != -1 && pri != lastpri) {
821 		if (dangling) {
822 			msgbuf_addchar(msgbufp, '\n');
823 			dangling = 0;
824 		}
825 		msgbuf_addchar(msgbufp, '<');
826 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL); *p;)
827 			msgbuf_addchar(msgbufp, *p--);
828 		msgbuf_addchar(msgbufp, '>');
829 		lastpri = pri;
830 	}
831 	msgbuf_addchar(msgbufp, c);
832 	if (c == '\n') {
833 		dangling = 0;
834 		lastpri = -1;
835 	} else {
836 		dangling = 1;
837 	}
838 }
839 
840 void
841 msgbufinit(void *ptr, int size)
842 {
843 	char *cp;
844 	static struct msgbuf *oldp = NULL;
845 
846 	size -= sizeof(*msgbufp);
847 	cp = (char *)ptr;
848 	msgbufp = (struct msgbuf *)(cp + size);
849 	msgbuf_reinit(msgbufp, cp, size);
850 	if (msgbufmapped && oldp != msgbufp)
851 		msgbuf_copy(oldp, msgbufp);
852 	msgbufmapped = 1;
853 	oldp = msgbufp;
854 }
855 
856 SYSCTL_DECL(_security_bsd);
857 
858 static int unprivileged_read_msgbuf = 1;
859 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_read_msgbuf,
860     CTLFLAG_RW, &unprivileged_read_msgbuf, 0,
861     "Unprivileged processes may read the kernel message buffer");
862 
863 /* Sysctls for accessing/clearing the msgbuf */
864 static int
865 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
866 {
867 	char buf[128];
868 	u_int seq;
869 	int error, len;
870 
871 	if (!unprivileged_read_msgbuf) {
872 		error = suser(req->td);
873 		if (error)
874 			return (error);
875 	}
876 
877 	/* Read the whole buffer, one chunk at a time. */
878 	msgbuf_peekbytes(msgbufp, NULL, 0, &seq);
879 	while ((len = msgbuf_peekbytes(msgbufp, buf, sizeof(buf), &seq)) > 0) {
880 		error = sysctl_handle_opaque(oidp, buf, len, req);
881 		if (error)
882 			return (error);
883 	}
884 	return (0);
885 }
886 
887 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
888     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
889 
890 static int msgbuf_clearflag;
891 
892 static int
893 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
894 {
895 	int error;
896 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
897 	if (!error && req->newptr) {
898 		msgbuf_clear(msgbufp);
899 		msgbuf_clearflag = 0;
900 	}
901 	return (error);
902 }
903 
904 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
905     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clearflag, 0,
906     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
907 
908 #ifdef DDB
909 
910 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
911 {
912 	int i, j, quit;
913 
914 	quit = 0;
915 
916 	if (!msgbufmapped) {
917 		db_printf("msgbuf not mapped yet\n");
918 		return;
919 	}
920 	db_setup_paging(db_simple_pager, &quit, db_lines_per_page);
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 && !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("|\n");
982 		}
983 	}
984 }
985 
986