xref: /freebsd/sys/kern/subr_prf.c (revision 77a0943ded95b9e6438f7db70c4a28e4d93946d4)
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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)subr_prf.c	8.3 (Berkeley) 1/21/94
39  * $FreeBSD$
40  */
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/kernel.h>
45 #include <sys/msgbuf.h>
46 #include <sys/malloc.h>
47 #include <sys/proc.h>
48 #include <sys/tty.h>
49 #include <sys/syslog.h>
50 #include <sys/cons.h>
51 
52 /*
53  * Note that stdarg.h and the ANSI style va_start macro is used for both
54  * ANSI and traditional C compilers.
55  */
56 #include <machine/stdarg.h>
57 
58 #define TOCONS	0x01
59 #define TOTTY	0x02
60 #define TOLOG	0x04
61 
62 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
63 #define MAXNBUF	(sizeof(quad_t) * NBBY + 1)
64 
65 struct putchar_arg {
66 	int	flags;
67 	struct	tty *tty;
68 };
69 
70 struct snprintf_arg {
71 	char	*str;
72 	size_t	remain;
73 };
74 
75 struct	tty *constty;			/* pointer to console "window" tty */
76 
77 static void (*v_putc)(int) = cnputc;	/* routine to putc on virtual console */
78 static void  logpri __P((int level));
79 static void  msglogchar(int c, void *dummyarg);
80 static void  putchar __P((int ch, void *arg));
81 static char *ksprintn __P((char *nbuf, u_long num, int base, int *len));
82 static char *ksprintqn __P((char *nbuf, u_quad_t num, int base, int *len));
83 static void  snprintf_func __P((int ch, void *arg));
84 
85 static int consintr = 1;		/* Ok to handle console interrupts? */
86 static int msgbufmapped;		/* Set when safe to use msgbuf */
87 
88 /*
89  * Warn that a system table is full.
90  */
91 void
92 tablefull(tab)
93 	const char *tab;
94 {
95 
96 	log(LOG_ERR, "%s: table is full\n", tab);
97 }
98 
99 /*
100  * Uprintf prints to the controlling terminal for the current process.
101  * It may block if the tty queue is overfull.  No message is printed if
102  * the queue does not clear in a reasonable time.
103  */
104 int
105 uprintf(const char *fmt, ...)
106 {
107 	struct proc *p = curproc;
108 	va_list ap;
109 	struct putchar_arg pca;
110 	int retval = 0;
111 
112 	if (p && p != idleproc && p->p_flag & P_CONTROLT &&
113 	    p->p_session->s_ttyvp) {
114 		va_start(ap, fmt);
115 		pca.tty = p->p_session->s_ttyp;
116 		pca.flags = TOTTY;
117 		retval = kvprintf(fmt, putchar, &pca, 10, ap);
118 		va_end(ap);
119 	}
120 	return retval;
121 }
122 
123 /*
124  * tprintf prints on the controlling terminal associated
125  * with the given session, possibly to the log as well.
126  */
127 void
128 tprintf(struct proc *p, int pri, const char *fmt, ...)
129 {
130 	struct tty *tp = NULL;
131 	int flags = 0, shld = 0;
132 	va_list ap;
133 	struct putchar_arg pca;
134 	int retval;
135 
136 	if (pri != -1) {
137 		logpri(pri);
138 		flags |= TOLOG;
139 	}
140 	if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
141 		SESSHOLD(p->p_session);
142 		shld++;
143 		if (ttycheckoutq(p->p_session->s_ttyp, 0)) {
144 			flags |= TOTTY;
145 			tp = p->p_session->s_ttyp;
146 		}
147 	}
148 	pca.tty = tp;
149 	pca.flags = flags;
150 	va_start(ap, fmt);
151 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
152 	va_end(ap);
153 	if (shld)
154 		SESSRELE(p->p_session);
155 	logwakeup();
156 }
157 
158 /*
159  * Ttyprintf displays a message on a tty; it should be used only by
160  * the tty driver, or anything that knows the underlying tty will not
161  * be revoke(2)'d away.  Other callers should use tprintf.
162  */
163 int
164 ttyprintf(struct tty *tp, const char *fmt, ...)
165 {
166 	va_list ap;
167 	struct putchar_arg pca;
168 	int retval;
169 
170 	va_start(ap, fmt);
171 	pca.tty = tp;
172 	pca.flags = TOTTY;
173 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
174 	va_end(ap);
175 	return retval;
176 }
177 
178 extern	int log_open;
179 
180 /*
181  * Log writes to the log buffer, and guarantees not to sleep (so can be
182  * called by interrupt routines).  If there is no process reading the
183  * log yet, it writes to the console also.
184  */
185 void
186 log(int level, const char *fmt, ...)
187 {
188 	int s;
189 	va_list ap;
190 	int retval;
191 
192 	s = splhigh();
193 	if (level != -1)
194 		logpri(level);
195 	va_start(ap, fmt);
196 
197 	retval = kvprintf(fmt, msglogchar, NULL, 10, ap);
198 	va_end(ap);
199 
200 	splx(s);
201 	if (!log_open) {
202 		struct putchar_arg pca;
203 		va_start(ap, fmt);
204 		pca.tty = NULL;
205 		pca.flags = TOCONS;
206 		retval += kvprintf(fmt, putchar, &pca, 10, ap);
207 		va_end(ap);
208 	}
209 	logwakeup();
210 }
211 
212 static void
213 logpri(level)
214 	int level;
215 {
216 	char nbuf[MAXNBUF];
217 	char *p;
218 
219 	msglogchar('<', NULL);
220 	for (p = ksprintn(nbuf, (u_long)level, 10, NULL); *p;)
221 		msglogchar(*p--, NULL);
222 	msglogchar('>', NULL);
223 }
224 
225 int
226 printf(const char *fmt, ...)
227 {
228 	va_list ap;
229 	int savintr;
230 	struct putchar_arg pca;
231 	int retval;
232 
233 	savintr = consintr;		/* disable interrupts */
234 	consintr = 0;
235 	va_start(ap, fmt);
236 	pca.tty = NULL;
237 	pca.flags = TOCONS | TOLOG;
238 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
239 	va_end(ap);
240 	if (!panicstr)
241 		logwakeup();
242 	consintr = savintr;		/* reenable interrupts */
243 	return retval;
244 }
245 
246 int
247 vprintf(const char *fmt, va_list ap)
248 {
249 	int savintr;
250 	struct putchar_arg pca;
251 	int retval;
252 
253 	savintr = consintr;		/* disable interrupts */
254 	consintr = 0;
255 	pca.tty = NULL;
256 	pca.flags = TOCONS | TOLOG;
257 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
258 	if (!panicstr)
259 		logwakeup();
260 	consintr = savintr;		/* reenable interrupts */
261 	return retval;
262 }
263 
264 /*
265  * Print a character on console or users terminal.  If destination is
266  * the console then the last bunch of characters are saved in msgbuf for
267  * inspection later.
268  */
269 static void
270 putchar(int c, void *arg)
271 {
272 	struct putchar_arg *ap = (struct putchar_arg*) arg;
273 	int flags = ap->flags;
274 	struct tty *tp = ap->tty;
275 	if (panicstr)
276 		constty = NULL;
277 	if ((flags & TOCONS) && tp == NULL && constty) {
278 		tp = constty;
279 		flags |= TOTTY;
280 	}
281 	if ((flags & TOTTY) && tp && tputchar(c, tp) < 0 &&
282 	    (flags & TOCONS) && tp == constty)
283 		constty = NULL;
284 	if ((flags & TOLOG))
285 		msglogchar(c, NULL);
286 	if ((flags & TOCONS) && constty == NULL && c != '\0')
287 		(*v_putc)(c);
288 }
289 
290 /*
291  * Scaled down version of sprintf(3).
292  */
293 int
294 sprintf(char *buf, const char *cfmt, ...)
295 {
296 	int retval;
297 	va_list ap;
298 
299 	va_start(ap, cfmt);
300 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
301 	buf[retval] = '\0';
302 	va_end(ap);
303 	return retval;
304 }
305 
306 /*
307  * Scaled down version of vsprintf(3).
308  */
309 int
310 vsprintf(char *buf, const char *cfmt, va_list ap)
311 {
312 	int retval;
313 
314 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
315 	buf[retval] = '\0';
316 	return retval;
317 }
318 
319 /*
320  * Scaled down version of snprintf(3).
321  */
322 int
323 snprintf(char *str, size_t size, const char *format, ...)
324 {
325 	int retval;
326 	va_list ap;
327 
328 	va_start(ap, format);
329 	retval = vsnprintf(str, size, format, ap);
330 	va_end(ap);
331 	return(retval);
332 }
333 
334 /*
335  * Scaled down version of vsnprintf(3).
336  */
337 int
338 vsnprintf(char *str, size_t size, const char *format, va_list ap)
339 {
340 	struct snprintf_arg info;
341 	int retval;
342 
343 	info.str = str;
344 	info.remain = size;
345 	retval = kvprintf(format, snprintf_func, &info, 10, ap);
346 	if (info.remain >= 1)
347 		*info.str++ = '\0';
348 	return retval;
349 }
350 
351 static void
352 snprintf_func(int ch, void *arg)
353 {
354 	struct snprintf_arg *const info = arg;
355 
356 	if (info->remain >= 2) {
357 		*info->str++ = ch;
358 		info->remain--;
359 	}
360 }
361 
362 /*
363  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
364  * order; return an optional length and a pointer to the last character
365  * written in the buffer (i.e., the first character of the string).
366  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
367  */
368 static char *
369 ksprintn(nbuf, ul, base, lenp)
370 	char *nbuf;
371 	u_long ul;
372 	int base, *lenp;
373 {
374 	char *p;
375 
376 	p = nbuf;
377 	*p = '\0';
378 	do {
379 		*++p = hex2ascii(ul % base);
380 	} while (ul /= base);
381 	if (lenp)
382 		*lenp = p - nbuf;
383 	return (p);
384 }
385 /* ksprintn, but for a quad_t. */
386 static char *
387 ksprintqn(nbuf, uq, base, lenp)
388 	char *nbuf;
389 	u_quad_t uq;
390 	int base, *lenp;
391 {
392 	char *p;
393 
394 	p = nbuf;
395 	*p = '\0';
396 	do {
397 		*++p = hex2ascii(uq % base);
398 	} while (uq /= base);
399 	if (lenp)
400 		*lenp = p - nbuf;
401 	return (p);
402 }
403 
404 /*
405  * Scaled down version of printf(3).
406  *
407  * Two additional formats:
408  *
409  * The format %b is supported to decode error registers.
410  * Its usage is:
411  *
412  *	printf("reg=%b\n", regval, "<base><arg>*");
413  *
414  * where <base> is the output base expressed as a control character, e.g.
415  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
416  * the first of which gives the bit number to be inspected (origin 1), and
417  * the next characters (up to a control character, i.e. a character <= 32),
418  * give the name of the register.  Thus:
419  *
420  *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
421  *
422  * would produce output:
423  *
424  *	reg=3<BITTWO,BITONE>
425  *
426  * XXX:  %D  -- Hexdump, takes pointer and separator string:
427  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
428  *		("%*D", len, ptr, " " -> XX XX XX XX ...
429  */
430 int
431 kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
432 {
433 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
434 	char nbuf[MAXNBUF];
435 	char *p, *q, *d;
436 	u_char *up;
437 	int ch, n;
438 	u_long ul;
439 	u_quad_t uq;
440 	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
441 	int dwidth;
442 	char padc;
443 	int retval = 0;
444 
445 	ul = 0;
446 	uq = 0;
447 	if (!func)
448 		d = (char *) arg;
449 	else
450 		d = NULL;
451 
452 	if (fmt == NULL)
453 		fmt = "(fmt null)\n";
454 
455 	if (radix < 2 || radix > 36)
456 		radix = 10;
457 
458 	for (;;) {
459 		padc = ' ';
460 		width = 0;
461 		while ((ch = (u_char)*fmt++) != '%') {
462 			if (ch == '\0')
463 				return retval;
464 			PCHAR(ch);
465 		}
466 		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
467 		sign = 0; dot = 0; dwidth = 0;
468 reswitch:	switch (ch = (u_char)*fmt++) {
469 		case '.':
470 			dot = 1;
471 			goto reswitch;
472 		case '#':
473 			sharpflag = 1;
474 			goto reswitch;
475 		case '+':
476 			sign = 1;
477 			goto reswitch;
478 		case '-':
479 			ladjust = 1;
480 			goto reswitch;
481 		case '%':
482 			PCHAR(ch);
483 			break;
484 		case '*':
485 			if (!dot) {
486 				width = va_arg(ap, int);
487 				if (width < 0) {
488 					ladjust = !ladjust;
489 					width = -width;
490 				}
491 			} else {
492 				dwidth = va_arg(ap, int);
493 			}
494 			goto reswitch;
495 		case '0':
496 			if (!dot) {
497 				padc = '0';
498 				goto reswitch;
499 			}
500 		case '1': case '2': case '3': case '4':
501 		case '5': case '6': case '7': case '8': case '9':
502 				for (n = 0;; ++fmt) {
503 					n = n * 10 + ch - '0';
504 					ch = *fmt;
505 					if (ch < '0' || ch > '9')
506 						break;
507 				}
508 			if (dot)
509 				dwidth = n;
510 			else
511 				width = n;
512 			goto reswitch;
513 		case 'b':
514 			ul = va_arg(ap, int);
515 			p = va_arg(ap, char *);
516 			for (q = ksprintn(nbuf, ul, *p++, NULL); *q;)
517 				PCHAR(*q--);
518 
519 			if (!ul)
520 				break;
521 
522 			for (tmp = 0; *p;) {
523 				n = *p++;
524 				if (ul & (1 << (n - 1))) {
525 					PCHAR(tmp ? ',' : '<');
526 					for (; (n = *p) > ' '; ++p)
527 						PCHAR(n);
528 					tmp = 1;
529 				} else
530 					for (; *p > ' '; ++p)
531 						continue;
532 			}
533 			if (tmp)
534 				PCHAR('>');
535 			break;
536 		case 'c':
537 			PCHAR(va_arg(ap, int));
538 			break;
539 		case 'D':
540 			up = va_arg(ap, u_char *);
541 			p = va_arg(ap, char *);
542 			if (!width)
543 				width = 16;
544 			while(width--) {
545 				PCHAR(hex2ascii(*up >> 4));
546 				PCHAR(hex2ascii(*up & 0x0f));
547 				up++;
548 				if (width)
549 					for (q=p;*q;q++)
550 						PCHAR(*q);
551 			}
552 			break;
553 		case 'd':
554 			if (qflag)
555 				uq = va_arg(ap, quad_t);
556 			else if (lflag)
557 				ul = va_arg(ap, long);
558 			else
559 				ul = va_arg(ap, int);
560 			sign = 1;
561 			base = 10;
562 			goto number;
563 		case 'l':
564 			if (lflag) {
565 				lflag = 0;
566 				qflag = 1;
567 			} else
568 				lflag = 1;
569 			goto reswitch;
570 		case 'o':
571 			if (qflag)
572 				uq = va_arg(ap, u_quad_t);
573 			else if (lflag)
574 				ul = va_arg(ap, u_long);
575 			else
576 				ul = va_arg(ap, u_int);
577 			base = 8;
578 			goto nosign;
579 		case 'p':
580 			ul = (uintptr_t)va_arg(ap, void *);
581 			base = 16;
582 			sharpflag = (width == 0);
583 			goto nosign;
584 		case 'q':
585 			qflag = 1;
586 			goto reswitch;
587 		case 'n':
588 		case 'r':
589 			if (qflag)
590 				uq = va_arg(ap, u_quad_t);
591 			else if (lflag)
592 				ul = va_arg(ap, u_long);
593 			else
594 				ul = sign ?
595 				    (u_long)va_arg(ap, int) : va_arg(ap, u_int);
596 			base = radix;
597 			goto number;
598 		case 's':
599 			p = va_arg(ap, char *);
600 			if (p == NULL)
601 				p = "(null)";
602 			if (!dot)
603 				n = strlen (p);
604 			else
605 				for (n = 0; n < dwidth && p[n]; n++)
606 					continue;
607 
608 			width -= n;
609 
610 			if (!ladjust && width > 0)
611 				while (width--)
612 					PCHAR(padc);
613 			while (n--)
614 				PCHAR(*p++);
615 			if (ladjust && width > 0)
616 				while (width--)
617 					PCHAR(padc);
618 			break;
619 		case 'u':
620 			if (qflag)
621 				uq = va_arg(ap, u_quad_t);
622 			else if (lflag)
623 				ul = va_arg(ap, u_long);
624 			else
625 				ul = va_arg(ap, u_int);
626 			base = 10;
627 			goto nosign;
628 		case 'x':
629 		case 'X':
630 			if (qflag)
631 				uq = va_arg(ap, u_quad_t);
632 			else if (lflag)
633 				ul = va_arg(ap, u_long);
634 			else
635 				ul = va_arg(ap, u_int);
636 			base = 16;
637 			goto nosign;
638 		case 'z':
639 			if (qflag)
640 				uq = va_arg(ap, u_quad_t);
641 			else if (lflag)
642 				ul = va_arg(ap, u_long);
643 			else
644 				ul = sign ?
645 				    (u_long)va_arg(ap, int) : va_arg(ap, u_int);
646 			base = 16;
647 			goto number;
648 nosign:			sign = 0;
649 number:
650 			if (qflag) {
651 				if (sign && (quad_t)uq < 0) {
652 					neg = 1;
653 					uq = -(quad_t)uq;
654 				}
655 				p = ksprintqn(nbuf, uq, base, &tmp);
656 			} else {
657 				if (sign && (long)ul < 0) {
658 					neg = 1;
659 					ul = -(long)ul;
660 				}
661 				p = ksprintn(nbuf, ul, base, &tmp);
662 			}
663 			if (sharpflag && (qflag ? uq != 0 : ul != 0)) {
664 				if (base == 8)
665 					tmp++;
666 				else if (base == 16)
667 					tmp += 2;
668 			}
669 			if (neg)
670 				tmp++;
671 
672 			if (!ladjust && width && (width -= tmp) > 0)
673 				while (width--)
674 					PCHAR(padc);
675 			if (neg)
676 				PCHAR('-');
677 			if (sharpflag && (qflag ? uq != 0 : ul != 0)) {
678 				if (base == 8) {
679 					PCHAR('0');
680 				} else if (base == 16) {
681 					PCHAR('0');
682 					PCHAR('x');
683 				}
684 			}
685 
686 			while (*p)
687 				PCHAR(*p--);
688 
689 			if (ladjust && width && (width -= tmp) > 0)
690 				while (width--)
691 					PCHAR(padc);
692 
693 			break;
694 		default:
695 			PCHAR('%');
696 			if (lflag)
697 				PCHAR('l');
698 			PCHAR(ch);
699 			break;
700 		}
701 	}
702 #undef PCHAR
703 }
704 
705 /*
706  * Put character in log buffer.
707  */
708 static void
709 msglogchar(int c, void *dummyarg)
710 {
711 	struct msgbuf *mbp;
712 
713 	if (c != '\0' && c != '\r' && c != 0177 && msgbufmapped) {
714 		mbp = msgbufp;
715 		mbp->msg_ptr[mbp->msg_bufx++] = c;
716 		if (mbp->msg_bufx >= mbp->msg_size)
717 			mbp->msg_bufx = 0;
718 		/* If the buffer is full, keep the most recent data. */
719 		if (mbp->msg_bufr == mbp->msg_bufx) {
720 			if (++mbp->msg_bufr >= mbp->msg_size)
721 				mbp->msg_bufr = 0;
722 		}
723 	}
724 }
725 
726 static void
727 msgbufcopy(struct msgbuf *oldp)
728 {
729 	int pos;
730 
731 	pos = oldp->msg_bufr;
732 	while (pos != oldp->msg_bufx) {
733 		msglogchar(oldp->msg_ptr[pos], NULL);
734 		if (++pos >= oldp->msg_size)
735 			pos = 0;
736 	}
737 }
738 
739 void
740 msgbufinit(void *ptr, size_t size)
741 {
742 	char *cp;
743 	static struct msgbuf *oldp = NULL;
744 
745 	cp = (char *)ptr;
746 	msgbufp = (struct msgbuf *) (cp + size - sizeof(*msgbufp));
747 	if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_ptr != cp) {
748 		bzero(cp, size);
749 		msgbufp->msg_magic = MSG_MAGIC;
750 		msgbufp->msg_size = (char *)msgbufp - cp;
751 		msgbufp->msg_ptr = cp;
752 	}
753 	if (msgbufmapped && oldp != msgbufp)
754 		msgbufcopy(oldp);
755 	msgbufmapped = 1;
756 	oldp = msgbufp;
757 }
758 
759 #include "opt_ddb.h"
760 #ifdef DDB
761 #include <ddb/ddb.h>
762 
763 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
764 {
765 	int i, j;
766 
767 	if (!msgbufmapped) {
768 		db_printf("msgbuf not mapped yet\n");
769 		return;
770 	}
771 	db_printf("msgbufp = %p\n", msgbufp);
772 	db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
773 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr,
774 	    msgbufp->msg_bufx, msgbufp->msg_ptr);
775 	for (i = 0; i < msgbufp->msg_size; i++) {
776 		j = (i + msgbufp->msg_bufr) % msgbufp->msg_size;
777 		db_printf("%c", msgbufp->msg_ptr[j]);
778 	}
779 	db_printf("\n");
780 }
781 
782 #endif /* DDB */
783