xref: /freebsd/sys/kern/subr_prf.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
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 #include "opt_printf.h"
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/lock.h>
46 #include <sys/kdb.h>
47 #include <sys/mutex.h>
48 #include <sys/sx.h>
49 #include <sys/kernel.h>
50 #include <sys/msgbuf.h>
51 #include <sys/malloc.h>
52 #include <sys/priv.h>
53 #include <sys/proc.h>
54 #include <sys/stddef.h>
55 #include <sys/sysctl.h>
56 #include <sys/tty.h>
57 #include <sys/syslog.h>
58 #include <sys/cons.h>
59 #include <sys/uio.h>
60 #include <sys/ctype.h>
61 
62 #ifdef DDB
63 #include <ddb/ddb.h>
64 #endif
65 
66 /*
67  * Note that stdarg.h and the ANSI style va_start macro is used for both
68  * ANSI and traditional C compilers.
69  */
70 #include <machine/stdarg.h>
71 
72 #define TOCONS	0x01
73 #define TOTTY	0x02
74 #define TOLOG	0x04
75 
76 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
77 #define MAXNBUF	(sizeof(intmax_t) * NBBY + 1)
78 
79 struct putchar_arg {
80 	int	flags;
81 	int	pri;
82 	struct	tty *tty;
83 	char	*p_bufr;
84 	size_t	n_bufr;
85 	char	*p_next;
86 	size_t	remain;
87 };
88 
89 struct snprintf_arg {
90 	char	*str;
91 	size_t	remain;
92 };
93 
94 extern	int log_open;
95 
96 static void  msglogchar(int c, int pri);
97 static void  putchar(int ch, void *arg);
98 static char *ksprintn(char *nbuf, uintmax_t num, int base, int *len, int upper);
99 static void  snprintf_func(int ch, void *arg);
100 
101 static int msgbufmapped;		/* Set when safe to use msgbuf */
102 int msgbuftrigger;
103 
104 static int      log_console_output = 1;
105 TUNABLE_INT("kern.log_console_output", &log_console_output);
106 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
107     &log_console_output, 0, "Duplicate console output to the syslog.");
108 
109 static int	always_console_output = 0;
110 TUNABLE_INT("kern.always_console_output", &always_console_output);
111 SYSCTL_INT(_kern, OID_AUTO, always_console_output, CTLFLAG_RW,
112     &always_console_output, 0, "Always output to console despite TIOCCONS.");
113 
114 /*
115  * Warn that a system table is full.
116  */
117 void
118 tablefull(const char *tab)
119 {
120 
121 	log(LOG_ERR, "%s: table is full\n", tab);
122 }
123 
124 /*
125  * Uprintf prints to the controlling terminal for the current process.
126  */
127 int
128 uprintf(const char *fmt, ...)
129 {
130 	struct thread *td = curthread;
131 	struct proc *p = td->td_proc;
132 	va_list ap;
133 	struct putchar_arg pca;
134 	int retval;
135 
136 	if (td == NULL || TD_IS_IDLETHREAD(td))
137 		return (0);
138 
139 	mtx_lock(&Giant);
140 	p = td->td_proc;
141 	PROC_LOCK(p);
142 	if ((p->p_flag & P_CONTROLT) == 0) {
143 		PROC_UNLOCK(p);
144 		retval = 0;
145 		goto out;
146 	}
147 	SESS_LOCK(p->p_session);
148 	pca.tty = p->p_session->s_ttyp;
149 	SESS_UNLOCK(p->p_session);
150 	PROC_UNLOCK(p);
151 	if (pca.tty == NULL) {
152 		retval = 0;
153 		goto out;
154 	}
155 	pca.flags = TOTTY;
156 	va_start(ap, fmt);
157 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
158 	va_end(ap);
159 out:
160 	mtx_unlock(&Giant);
161 	return (retval);
162 }
163 
164 /*
165  * tprintf prints on the controlling terminal associated with the given
166  * session, possibly to the log as well.
167  */
168 void
169 tprintf(struct proc *p, int pri, const char *fmt, ...)
170 {
171 	struct tty *tp = NULL;
172 	int flags = 0;
173 	va_list ap;
174 	struct putchar_arg pca;
175 	struct session *sess = NULL;
176 
177 	mtx_lock(&Giant);
178 	if (pri != -1)
179 		flags |= TOLOG;
180 	if (p != NULL) {
181 		PROC_LOCK(p);
182 		if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
183 			sess = p->p_session;
184 			SESS_LOCK(sess);
185 			PROC_UNLOCK(p);
186 			SESSHOLD(sess);
187 			tp = sess->s_ttyp;
188 			SESS_UNLOCK(sess);
189 			if (ttycheckoutq(tp, 0))
190 				flags |= TOTTY;
191 			else
192 				tp = NULL;
193 		} else
194 			PROC_UNLOCK(p);
195 	}
196 	pca.pri = pri;
197 	pca.tty = tp;
198 	pca.flags = flags;
199 	va_start(ap, fmt);
200 	kvprintf(fmt, putchar, &pca, 10, ap);
201 	va_end(ap);
202 	if (sess != NULL)
203 		SESSRELE(sess);
204 	msgbuftrigger = 1;
205 	mtx_unlock(&Giant);
206 }
207 
208 /*
209  * Ttyprintf displays a message on a tty; it should be used only by
210  * the tty driver, or anything that knows the underlying tty will not
211  * be revoke(2)'d away.  Other callers should use tprintf.
212  */
213 int
214 ttyprintf(struct tty *tp, const char *fmt, ...)
215 {
216 	va_list ap;
217 	struct putchar_arg pca;
218 	int retval;
219 
220 	va_start(ap, fmt);
221 	pca.tty = tp;
222 	pca.flags = TOTTY;
223 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
224 	va_end(ap);
225 	return (retval);
226 }
227 
228 /*
229  * Log writes to the log buffer, and guarantees not to sleep (so can be
230  * called by interrupt routines).  If there is no process reading the
231  * log yet, it writes to the console also.
232  */
233 void
234 log(int level, const char *fmt, ...)
235 {
236 	va_list ap;
237 	struct putchar_arg pca;
238 
239 	pca.tty = NULL;
240 	pca.pri = level;
241 	pca.flags = log_open ? TOLOG : TOCONS;
242 	pca.p_bufr = NULL;
243 
244 	va_start(ap, fmt);
245 	kvprintf(fmt, putchar, &pca, 10, ap);
246 	va_end(ap);
247 
248 	msgbuftrigger = 1;
249 }
250 
251 #define CONSCHUNK 128
252 
253 void
254 log_console(struct uio *uio)
255 {
256 	int c, i, error, nl;
257 	char *consbuffer;
258 	int pri;
259 
260 	if (!log_console_output)
261 		return;
262 
263 	pri = LOG_INFO | LOG_CONSOLE;
264 	uio = cloneuio(uio);
265 	consbuffer = malloc(CONSCHUNK, M_TEMP, M_WAITOK);
266 
267 	nl = 0;
268 	while (uio->uio_resid > 0) {
269 		c = imin(uio->uio_resid, CONSCHUNK);
270 		error = uiomove(consbuffer, c, uio);
271 		if (error != 0)
272 			break;
273 		for (i = 0; i < c; i++) {
274 			msglogchar(consbuffer[i], pri);
275 			if (consbuffer[i] == '\n')
276 				nl = 1;
277 			else
278 				nl = 0;
279 		}
280 	}
281 	if (!nl)
282 		msglogchar('\n', pri);
283 	msgbuftrigger = 1;
284 	free(uio, M_IOV);
285 	free(consbuffer, M_TEMP);
286 	return;
287 }
288 
289 int
290 printf(const char *fmt, ...)
291 {
292 	va_list ap;
293 	struct putchar_arg pca;
294 	int retval;
295 #ifdef PRINTF_BUFR_SIZE
296 	char bufr[PRINTF_BUFR_SIZE];
297 #endif
298 
299 	va_start(ap, fmt);
300 	pca.tty = NULL;
301 	pca.flags = TOCONS | TOLOG;
302 	pca.pri = -1;
303 #ifdef PRINTF_BUFR_SIZE
304 	pca.p_bufr = bufr;
305 	pca.p_next = pca.p_bufr;
306 	pca.n_bufr = sizeof(bufr);
307 	pca.remain = sizeof(bufr);
308 	*pca.p_next = '\0';
309 #else
310 	/* Don't buffer console output. */
311 	pca.p_bufr = NULL;
312 #endif
313 
314 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
315 	va_end(ap);
316 
317 #ifdef PRINTF_BUFR_SIZE
318 	/* Write any buffered console output: */
319 	if (*pca.p_bufr != '\0')
320 		cnputs(pca.p_bufr);
321 #endif
322 
323 	if (!panicstr)
324 		msgbuftrigger = 1;
325 
326 	return (retval);
327 }
328 
329 int
330 vprintf(const char *fmt, va_list ap)
331 {
332 	struct putchar_arg pca;
333 	int retval;
334 #ifdef PRINTF_BUFR_SIZE
335 	char bufr[PRINTF_BUFR_SIZE];
336 #endif
337 
338 	pca.tty = NULL;
339 	pca.flags = TOCONS | TOLOG;
340 	pca.pri = -1;
341 #ifdef PRINTF_BUFR_SIZE
342 	pca.p_bufr = bufr;
343 	pca.p_next = pca.p_bufr;
344 	pca.n_bufr = sizeof(bufr);
345 	pca.remain = sizeof(bufr);
346 	*pca.p_next = '\0';
347 #else
348 	/* Don't buffer console output. */
349 	pca.p_bufr = NULL;
350 #endif
351 
352 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
353 
354 #ifdef PRINTF_BUFR_SIZE
355 	/* Write any buffered console output: */
356 	if (*pca.p_bufr != '\0')
357 		cnputs(pca.p_bufr);
358 #endif
359 
360 	if (!panicstr)
361 		msgbuftrigger = 1;
362 
363 	return (retval);
364 }
365 
366 static void
367 putcons(int c, struct putchar_arg *ap)
368 {
369 	/* Check if no console output buffer was provided. */
370 	if (ap->p_bufr == NULL)
371 		/* Output direct to the console. */
372 		cnputc(c);
373 	else {
374 		/* Buffer the character: */
375 		if (c == '\n') {
376 			*ap->p_next++ = '\r';
377 			ap->remain--;
378 		}
379 		*ap->p_next++ = c;
380 		ap->remain--;
381 
382 		/* Always leave the buffer zero terminated. */
383 		*ap->p_next = '\0';
384 
385 		/* Check if the buffer needs to be flushed. */
386 		if (ap->remain < 3 || c == '\n') {
387 			cnputs(ap->p_bufr);
388 			ap->p_next = ap->p_bufr;
389 			ap->remain = ap->n_bufr;
390 			*ap->p_next = '\0';
391 		}
392 	}
393 }
394 
395 /*
396  * Print a character on console or users terminal.  If destination is
397  * the console then the last bunch of characters are saved in msgbuf for
398  * inspection later.
399  */
400 static void
401 putchar(int c, void *arg)
402 {
403 	struct putchar_arg *ap = (struct putchar_arg*) arg;
404 	struct tty *tp = ap->tty;
405 	int flags = ap->flags;
406 
407 	/* Don't use the tty code after a panic or while in ddb. */
408 	if (kdb_active) {
409 		if (c != '\0')
410 			cnputc(c);
411 	} else if (panicstr || ((flags & TOCONS) && constty == NULL)) {
412 		if (c != '\0')
413 			putcons(c, ap);
414 	} else {
415 		if ((flags & TOTTY) && tp != NULL)
416 			tputchar(c, tp);
417 		if (flags & TOCONS) {
418 			if (constty != NULL)
419 				msgbuf_addchar(&consmsgbuf, c);
420 			if (always_console_output && c != '\0')
421 				putcons(c, ap);
422 		}
423 	}
424 	if ((flags & TOLOG))
425 		msglogchar(c, ap->pri);
426 }
427 
428 /*
429  * Scaled down version of sprintf(3).
430  */
431 int
432 sprintf(char *buf, const char *cfmt, ...)
433 {
434 	int retval;
435 	va_list ap;
436 
437 	va_start(ap, cfmt);
438 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
439 	buf[retval] = '\0';
440 	va_end(ap);
441 	return (retval);
442 }
443 
444 /*
445  * Scaled down version of vsprintf(3).
446  */
447 int
448 vsprintf(char *buf, const char *cfmt, va_list ap)
449 {
450 	int retval;
451 
452 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
453 	buf[retval] = '\0';
454 	return (retval);
455 }
456 
457 /*
458  * Scaled down version of snprintf(3).
459  */
460 int
461 snprintf(char *str, size_t size, const char *format, ...)
462 {
463 	int retval;
464 	va_list ap;
465 
466 	va_start(ap, format);
467 	retval = vsnprintf(str, size, format, ap);
468 	va_end(ap);
469 	return(retval);
470 }
471 
472 /*
473  * Scaled down version of vsnprintf(3).
474  */
475 int
476 vsnprintf(char *str, size_t size, const char *format, va_list ap)
477 {
478 	struct snprintf_arg info;
479 	int retval;
480 
481 	info.str = str;
482 	info.remain = size;
483 	retval = kvprintf(format, snprintf_func, &info, 10, ap);
484 	if (info.remain >= 1)
485 		*info.str++ = '\0';
486 	return (retval);
487 }
488 
489 /*
490  * Kernel version which takes radix argument vsnprintf(3).
491  */
492 int
493 vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
494 {
495 	struct snprintf_arg info;
496 	int retval;
497 
498 	info.str = str;
499 	info.remain = size;
500 	retval = kvprintf(format, snprintf_func, &info, radix, ap);
501 	if (info.remain >= 1)
502 		*info.str++ = '\0';
503 	return (retval);
504 }
505 
506 static void
507 snprintf_func(int ch, void *arg)
508 {
509 	struct snprintf_arg *const info = arg;
510 
511 	if (info->remain >= 2) {
512 		*info->str++ = ch;
513 		info->remain--;
514 	}
515 }
516 
517 /*
518  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
519  * order; return an optional length and a pointer to the last character
520  * written in the buffer (i.e., the first character of the string).
521  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
522  */
523 static char *
524 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
525 {
526 	char *p, c;
527 
528 	p = nbuf;
529 	*p = '\0';
530 	do {
531 		c = hex2ascii(num % base);
532 		*++p = upper ? toupper(c) : c;
533 	} while (num /= base);
534 	if (lenp)
535 		*lenp = p - nbuf;
536 	return (p);
537 }
538 
539 /*
540  * Scaled down version of printf(3).
541  *
542  * Two additional formats:
543  *
544  * The format %b is supported to decode error registers.
545  * Its usage is:
546  *
547  *	printf("reg=%b\n", regval, "<base><arg>*");
548  *
549  * where <base> is the output base expressed as a control character, e.g.
550  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
551  * the first of which gives the bit number to be inspected (origin 1), and
552  * the next characters (up to a control character, i.e. a character <= 32),
553  * give the name of the register.  Thus:
554  *
555  *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
556  *
557  * would produce output:
558  *
559  *	reg=3<BITTWO,BITONE>
560  *
561  * XXX:  %D  -- Hexdump, takes pointer and separator string:
562  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
563  *		("%*D", len, ptr, " " -> XX XX XX XX ...
564  */
565 int
566 kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
567 {
568 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
569 	char nbuf[MAXNBUF];
570 	char *d;
571 	const char *p, *percent, *q;
572 	u_char *up;
573 	int ch, n;
574 	uintmax_t num;
575 	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
576 	int cflag, hflag, jflag, tflag, zflag;
577 	int dwidth, upper;
578 	char padc;
579 	int stop = 0, retval = 0;
580 
581 	num = 0;
582 	if (!func)
583 		d = (char *) arg;
584 	else
585 		d = NULL;
586 
587 	if (fmt == NULL)
588 		fmt = "(fmt null)\n";
589 
590 	if (radix < 2 || radix > 36)
591 		radix = 10;
592 
593 	for (;;) {
594 		padc = ' ';
595 		width = 0;
596 		while ((ch = (u_char)*fmt++) != '%' || stop) {
597 			if (ch == '\0')
598 				return (retval);
599 			PCHAR(ch);
600 		}
601 		percent = fmt - 1;
602 		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
603 		sign = 0; dot = 0; dwidth = 0; upper = 0;
604 		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
605 reswitch:	switch (ch = (u_char)*fmt++) {
606 		case '.':
607 			dot = 1;
608 			goto reswitch;
609 		case '#':
610 			sharpflag = 1;
611 			goto reswitch;
612 		case '+':
613 			sign = 1;
614 			goto reswitch;
615 		case '-':
616 			ladjust = 1;
617 			goto reswitch;
618 		case '%':
619 			PCHAR(ch);
620 			break;
621 		case '*':
622 			if (!dot) {
623 				width = va_arg(ap, int);
624 				if (width < 0) {
625 					ladjust = !ladjust;
626 					width = -width;
627 				}
628 			} else {
629 				dwidth = va_arg(ap, int);
630 			}
631 			goto reswitch;
632 		case '0':
633 			if (!dot) {
634 				padc = '0';
635 				goto reswitch;
636 			}
637 		case '1': case '2': case '3': case '4':
638 		case '5': case '6': case '7': case '8': case '9':
639 				for (n = 0;; ++fmt) {
640 					n = n * 10 + ch - '0';
641 					ch = *fmt;
642 					if (ch < '0' || ch > '9')
643 						break;
644 				}
645 			if (dot)
646 				dwidth = n;
647 			else
648 				width = n;
649 			goto reswitch;
650 		case 'b':
651 			num = (u_int)va_arg(ap, int);
652 			p = va_arg(ap, char *);
653 			for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
654 				PCHAR(*q--);
655 
656 			if (num == 0)
657 				break;
658 
659 			for (tmp = 0; *p;) {
660 				n = *p++;
661 				if (num & (1 << (n - 1))) {
662 					PCHAR(tmp ? ',' : '<');
663 					for (; (n = *p) > ' '; ++p)
664 						PCHAR(n);
665 					tmp = 1;
666 				} else
667 					for (; *p > ' '; ++p)
668 						continue;
669 			}
670 			if (tmp)
671 				PCHAR('>');
672 			break;
673 		case 'c':
674 			PCHAR(va_arg(ap, int));
675 			break;
676 		case 'D':
677 			up = va_arg(ap, u_char *);
678 			p = va_arg(ap, char *);
679 			if (!width)
680 				width = 16;
681 			while(width--) {
682 				PCHAR(hex2ascii(*up >> 4));
683 				PCHAR(hex2ascii(*up & 0x0f));
684 				up++;
685 				if (width)
686 					for (q=p;*q;q++)
687 						PCHAR(*q);
688 			}
689 			break;
690 		case 'd':
691 		case 'i':
692 			base = 10;
693 			sign = 1;
694 			goto handle_sign;
695 		case 'h':
696 			if (hflag) {
697 				hflag = 0;
698 				cflag = 1;
699 			} else
700 				hflag = 1;
701 			goto reswitch;
702 		case 'j':
703 			jflag = 1;
704 			goto reswitch;
705 		case 'l':
706 			if (lflag) {
707 				lflag = 0;
708 				qflag = 1;
709 			} else
710 				lflag = 1;
711 			goto reswitch;
712 		case 'n':
713 			if (jflag)
714 				*(va_arg(ap, intmax_t *)) = retval;
715 			else if (qflag)
716 				*(va_arg(ap, quad_t *)) = retval;
717 			else if (lflag)
718 				*(va_arg(ap, long *)) = retval;
719 			else if (zflag)
720 				*(va_arg(ap, size_t *)) = retval;
721 			else if (hflag)
722 				*(va_arg(ap, short *)) = retval;
723 			else if (cflag)
724 				*(va_arg(ap, char *)) = retval;
725 			else
726 				*(va_arg(ap, int *)) = retval;
727 			break;
728 		case 'o':
729 			base = 8;
730 			goto handle_nosign;
731 		case 'p':
732 			base = 16;
733 			sharpflag = (width == 0);
734 			sign = 0;
735 			num = (uintptr_t)va_arg(ap, void *);
736 			goto number;
737 		case 'q':
738 			qflag = 1;
739 			goto reswitch;
740 		case 'r':
741 			base = radix;
742 			if (sign)
743 				goto handle_sign;
744 			goto handle_nosign;
745 		case 's':
746 			p = va_arg(ap, char *);
747 			if (p == NULL)
748 				p = "(null)";
749 			if (!dot)
750 				n = strlen (p);
751 			else
752 				for (n = 0; n < dwidth && p[n]; n++)
753 					continue;
754 
755 			width -= n;
756 
757 			if (!ladjust && width > 0)
758 				while (width--)
759 					PCHAR(padc);
760 			while (n--)
761 				PCHAR(*p++);
762 			if (ladjust && width > 0)
763 				while (width--)
764 					PCHAR(padc);
765 			break;
766 		case 't':
767 			tflag = 1;
768 			goto reswitch;
769 		case 'u':
770 			base = 10;
771 			goto handle_nosign;
772 		case 'X':
773 			upper = 1;
774 		case 'x':
775 			base = 16;
776 			goto handle_nosign;
777 		case 'y':
778 			base = 16;
779 			sign = 1;
780 			goto handle_sign;
781 		case 'z':
782 			zflag = 1;
783 			goto reswitch;
784 handle_nosign:
785 			sign = 0;
786 			if (jflag)
787 				num = va_arg(ap, uintmax_t);
788 			else if (qflag)
789 				num = va_arg(ap, u_quad_t);
790 			else if (tflag)
791 				num = va_arg(ap, ptrdiff_t);
792 			else if (lflag)
793 				num = va_arg(ap, u_long);
794 			else if (zflag)
795 				num = va_arg(ap, size_t);
796 			else if (hflag)
797 				num = (u_short)va_arg(ap, int);
798 			else if (cflag)
799 				num = (u_char)va_arg(ap, int);
800 			else
801 				num = va_arg(ap, u_int);
802 			goto number;
803 handle_sign:
804 			if (jflag)
805 				num = va_arg(ap, intmax_t);
806 			else if (qflag)
807 				num = va_arg(ap, quad_t);
808 			else if (tflag)
809 				num = va_arg(ap, ptrdiff_t);
810 			else if (lflag)
811 				num = va_arg(ap, long);
812 			else if (zflag)
813 				num = va_arg(ap, size_t);
814 			else if (hflag)
815 				num = (short)va_arg(ap, int);
816 			else if (cflag)
817 				num = (char)va_arg(ap, int);
818 			else
819 				num = va_arg(ap, int);
820 number:
821 			if (sign && (intmax_t)num < 0) {
822 				neg = 1;
823 				num = -(intmax_t)num;
824 			}
825 			p = ksprintn(nbuf, num, base, &tmp, upper);
826 			if (sharpflag && num != 0) {
827 				if (base == 8)
828 					tmp++;
829 				else if (base == 16)
830 					tmp += 2;
831 			}
832 			if (neg)
833 				tmp++;
834 
835 			if (!ladjust && padc != '0' && width
836 			    && (width -= tmp) > 0)
837 				while (width--)
838 					PCHAR(padc);
839 			if (neg)
840 				PCHAR('-');
841 			if (sharpflag && num != 0) {
842 				if (base == 8) {
843 					PCHAR('0');
844 				} else if (base == 16) {
845 					PCHAR('0');
846 					PCHAR('x');
847 				}
848 			}
849 			if (!ladjust && width && (width -= tmp) > 0)
850 				while (width--)
851 					PCHAR(padc);
852 
853 			while (*p)
854 				PCHAR(*p--);
855 
856 			if (ladjust && width && (width -= tmp) > 0)
857 				while (width--)
858 					PCHAR(padc);
859 
860 			break;
861 		default:
862 			while (percent < fmt)
863 				PCHAR(*percent++);
864 			/*
865 			 * Since we ignore an formatting argument it is no
866 			 * longer safe to obey the remaining formatting
867 			 * arguments as the arguments will no longer match
868 			 * the format specs.
869 			 */
870 			stop = 1;
871 			break;
872 		}
873 	}
874 #undef PCHAR
875 }
876 
877 /*
878  * Put character in log buffer with a particular priority.
879  */
880 static void
881 msglogchar(int c, int pri)
882 {
883 	static int lastpri = -1;
884 	static int dangling;
885 	char nbuf[MAXNBUF];
886 	char *p;
887 
888 	if (!msgbufmapped)
889 		return;
890 	if (c == '\0' || c == '\r')
891 		return;
892 	if (pri != -1 && pri != lastpri) {
893 		if (dangling) {
894 			msgbuf_addchar(msgbufp, '\n');
895 			dangling = 0;
896 		}
897 		msgbuf_addchar(msgbufp, '<');
898 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
899 			msgbuf_addchar(msgbufp, *p--);
900 		msgbuf_addchar(msgbufp, '>');
901 		lastpri = pri;
902 	}
903 	msgbuf_addchar(msgbufp, c);
904 	if (c == '\n') {
905 		dangling = 0;
906 		lastpri = -1;
907 	} else {
908 		dangling = 1;
909 	}
910 }
911 
912 void
913 msgbufinit(void *ptr, int size)
914 {
915 	char *cp;
916 	static struct msgbuf *oldp = NULL;
917 
918 	size -= sizeof(*msgbufp);
919 	cp = (char *)ptr;
920 	msgbufp = (struct msgbuf *)(cp + size);
921 	msgbuf_reinit(msgbufp, cp, size);
922 	if (msgbufmapped && oldp != msgbufp)
923 		msgbuf_copy(oldp, msgbufp);
924 	msgbufmapped = 1;
925 	oldp = msgbufp;
926 }
927 
928 static int unprivileged_read_msgbuf = 1;
929 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_read_msgbuf,
930     CTLFLAG_RW, &unprivileged_read_msgbuf, 0,
931     "Unprivileged processes may read the kernel message buffer");
932 
933 /* Sysctls for accessing/clearing the msgbuf */
934 static int
935 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
936 {
937 	char buf[128];
938 	u_int seq;
939 	int error, len;
940 
941 	if (!unprivileged_read_msgbuf) {
942 		error = priv_check(req->td, PRIV_MSGBUF);
943 		if (error)
944 			return (error);
945 	}
946 
947 	/* Read the whole buffer, one chunk at a time. */
948 	msgbuf_peekbytes(msgbufp, NULL, 0, &seq);
949 	while ((len = msgbuf_peekbytes(msgbufp, buf, sizeof(buf), &seq)) > 0) {
950 		error = sysctl_handle_opaque(oidp, buf, len, req);
951 		if (error)
952 			return (error);
953 	}
954 	return (0);
955 }
956 
957 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
958     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
959 
960 static int msgbuf_clearflag;
961 
962 static int
963 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
964 {
965 	int error;
966 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
967 	if (!error && req->newptr) {
968 		msgbuf_clear(msgbufp);
969 		msgbuf_clearflag = 0;
970 	}
971 	return (error);
972 }
973 
974 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
975     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clearflag, 0,
976     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
977 
978 #ifdef DDB
979 
980 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
981 {
982 	int i, j;
983 
984 	if (!msgbufmapped) {
985 		db_printf("msgbuf not mapped yet\n");
986 		return;
987 	}
988 	db_printf("msgbufp = %p\n", msgbufp);
989 	db_printf("magic = %x, size = %d, r= %u, w = %u, ptr = %p, cksum= %u\n",
990 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_rseq,
991 	    msgbufp->msg_wseq, msgbufp->msg_ptr, msgbufp->msg_cksum);
992 	for (i = 0; i < msgbufp->msg_size && !db_pager_quit; i++) {
993 		j = MSGBUF_SEQ_TO_POS(msgbufp, i + msgbufp->msg_rseq);
994 		db_printf("%c", msgbufp->msg_ptr[j]);
995 	}
996 	db_printf("\n");
997 }
998 
999 #endif /* DDB */
1000 
1001 void
1002 hexdump(const void *ptr, int length, const char *hdr, int flags)
1003 {
1004 	int i, j, k;
1005 	int cols;
1006 	const unsigned char *cp;
1007 	char delim;
1008 
1009 	if ((flags & HD_DELIM_MASK) != 0)
1010 		delim = (flags & HD_DELIM_MASK) >> 8;
1011 	else
1012 		delim = ' ';
1013 
1014 	if ((flags & HD_COLUMN_MASK) != 0)
1015 		cols = flags & HD_COLUMN_MASK;
1016 	else
1017 		cols = 16;
1018 
1019 	cp = ptr;
1020 	for (i = 0; i < length; i+= cols) {
1021 		if (hdr != NULL)
1022 			printf("%s", hdr);
1023 
1024 		if ((flags & HD_OMIT_COUNT) == 0)
1025 			printf("%04x  ", i);
1026 
1027 		if ((flags & HD_OMIT_HEX) == 0) {
1028 			for (j = 0; j < cols; j++) {
1029 				k = i + j;
1030 				if (k < length)
1031 					printf("%c%02x", delim, cp[k]);
1032 				else
1033 					printf("   ");
1034 			}
1035 		}
1036 
1037 		if ((flags & HD_OMIT_CHARS) == 0) {
1038 			printf("  |");
1039 			for (j = 0; j < cols; j++) {
1040 				k = i + j;
1041 				if (k >= length)
1042 					printf(" ");
1043 				else if (cp[k] >= ' ' && cp[k] <= '~')
1044 					printf("%c", cp[k]);
1045 				else
1046 					printf(".");
1047 			}
1048 			printf("|");
1049 		}
1050 		printf("\n");
1051 	}
1052 }
1053 
1054