hexdump.c revision 116660 
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 */
40
41#include <sys/cdefs.h>
42__FBSDID("$FreeBSD: head/sys/kern/subr_prf.c 116660 2003-06-22 02:18:31Z iedowse $");
43
44#include "opt_ddb.h"
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/lock.h>
49#include <sys/mutex.h>
50#include <sys/sx.h>
51#include <sys/kernel.h>
52#include <sys/msgbuf.h>
53#include <sys/malloc.h>
54#include <sys/proc.h>
55#include <sys/stddef.h>
56#include <sys/sysctl.h>
57#include <sys/tty.h>
58#include <sys/syslog.h>
59#include <sys/cons.h>
60#include <sys/uio.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
79struct putchar_arg {
80	int	flags;
81	int	pri;
82	struct	tty *tty;
83};
84
85struct snprintf_arg {
86	char	*str;
87	size_t	remain;
88};
89
90extern	int log_open;
91
92struct	tty *constty;			/* pointer to console "window" tty */
93
94static void (*v_putc)(int) = cnputc;	/* routine to putc on virtual console */
95static void  msglogchar(int c, int pri);
96static void  putchar(int ch, void *arg);
97static char *ksprintn(char *nbuf, uintmax_t num, int base, int *len);
98static void  snprintf_func(int ch, void *arg);
99
100static int consintr = 1;		/* Ok to handle console interrupts? */
101static int msgbufmapped;		/* Set when safe to use msgbuf */
102int msgbuftrigger;
103
104static int      log_console_output = 1;
105TUNABLE_INT("kern.log_console_output", &log_console_output);
106SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
107    &log_console_output, 0, "");
108
109/*
110 * Warn that a system table is full.
111 */
112void
113tablefull(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 * It may block if the tty queue is overfull.  No message is printed if
122 * the queue does not clear in a reasonable time.
123 */
124int
125uprintf(const char *fmt, ...)
126{
127	struct thread *td = curthread;
128	struct proc *p = td->td_proc;
129	va_list ap;
130	struct putchar_arg pca;
131	int retval;
132
133	if (td == NULL || td == PCPU_GET(idlethread))
134		return (0);
135
136	p = td->td_proc;
137	PROC_LOCK(p);
138	if ((p->p_flag & P_CONTROLT) == 0) {
139		PROC_UNLOCK(p);
140		return (0);
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		return (0);
148	pca.flags = TOTTY;
149	va_start(ap, fmt);
150	retval = kvprintf(fmt, putchar, &pca, 10, ap);
151	va_end(ap);
152
153	return (retval);
154}
155
156/*
157 * tprintf prints on the controlling terminal associated
158 * with the given session, possibly to the log as well.
159 */
160void
161tprintf(struct proc *p, int pri, const char *fmt, ...)
162{
163	struct tty *tp = NULL;
164	int flags = 0;
165	va_list ap;
166	struct putchar_arg pca;
167	struct session *sess = NULL;
168
169	if (pri != -1)
170		flags |= TOLOG;
171	if (p != NULL) {
172		PROC_LOCK(p);
173		if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
174			sess = p->p_session;
175			SESS_LOCK(sess);
176			PROC_UNLOCK(p);
177			SESSHOLD(sess);
178			tp = sess->s_ttyp;
179			SESS_UNLOCK(sess);
180			if (ttycheckoutq(tp, 0))
181				flags |= TOTTY;
182			else
183				tp = NULL;
184		} else
185			PROC_UNLOCK(p);
186	}
187	pca.pri = pri;
188	pca.tty = tp;
189	pca.flags = flags;
190	va_start(ap, fmt);
191	kvprintf(fmt, putchar, &pca, 10, ap);
192	va_end(ap);
193	if (sess != NULL) {
194		SESS_LOCK(sess);
195		SESSRELE(sess);
196		SESS_UNLOCK(sess);
197	}
198	msgbuftrigger = 1;
199}
200
201/*
202 * Ttyprintf displays a message on a tty; it should be used only by
203 * the tty driver, or anything that knows the underlying tty will not
204 * be revoke(2)'d away.  Other callers should use tprintf.
205 */
206int
207ttyprintf(struct tty *tp, const char *fmt, ...)
208{
209	va_list ap;
210	struct putchar_arg pca;
211	int retval;
212
213	va_start(ap, fmt);
214	pca.tty = tp;
215	pca.flags = TOTTY;
216	retval = kvprintf(fmt, putchar, &pca, 10, ap);
217	va_end(ap);
218	return (retval);
219}
220
221/*
222 * Log writes to the log buffer, and guarantees not to sleep (so can be
223 * called by interrupt routines).  If there is no process reading the
224 * log yet, it writes to the console also.
225 */
226void
227log(int level, const char *fmt, ...)
228{
229	va_list ap;
230	struct putchar_arg pca;
231
232	pca.tty = NULL;
233	pca.pri = level;
234	pca.flags = log_open ? TOLOG : TOCONS;
235
236	va_start(ap, fmt);
237	kvprintf(fmt, putchar, &pca, 10, ap);
238	va_end(ap);
239
240	msgbuftrigger = 1;
241}
242
243#define CONSCHUNK 128
244
245void
246log_console(struct uio *uio)
247{
248	int c, i, error, iovlen, nl;
249	struct uio muio;
250	struct iovec *miov = NULL;
251	char *consbuffer;
252	int pri;
253
254	if (!log_console_output)
255		return;
256
257	pri = LOG_INFO | LOG_CONSOLE;
258	muio = *uio;
259	iovlen = uio->uio_iovcnt * sizeof (struct iovec);
260	MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
261	MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
262	bcopy(muio.uio_iov, miov, iovlen);
263	muio.uio_iov = miov;
264	uio = &muio;
265
266	nl = 0;
267	while (uio->uio_resid > 0) {
268		c = imin(uio->uio_resid, CONSCHUNK);
269		error = uiomove(consbuffer, c, uio);
270		if (error != 0)
271			break;
272		for (i = 0; i < c; i++) {
273			msglogchar(consbuffer[i], pri);
274			if (consbuffer[i] == '\n')
275				nl = 1;
276			else
277				nl = 0;
278		}
279	}
280	if (!nl)
281		msglogchar('\n', pri);
282	msgbuftrigger = 1;
283	FREE(miov, M_TEMP);
284	FREE(consbuffer, M_TEMP);
285	return;
286}
287
288int
289printf(const char *fmt, ...)
290{
291	va_list ap;
292	int savintr;
293	struct putchar_arg pca;
294	int retval;
295
296	savintr = consintr;		/* disable interrupts */
297	consintr = 0;
298	va_start(ap, fmt);
299	pca.tty = NULL;
300	pca.flags = TOCONS | TOLOG;
301	pca.pri = -1;
302	retval = kvprintf(fmt, putchar, &pca, 10, ap);
303	va_end(ap);
304	if (!panicstr)
305		msgbuftrigger = 1;
306	consintr = savintr;		/* reenable interrupts */
307	return (retval);
308}
309
310int
311vprintf(const char *fmt, va_list ap)
312{
313	int savintr;
314	struct putchar_arg pca;
315	int retval;
316
317	savintr = consintr;		/* disable interrupts */
318	consintr = 0;
319	pca.tty = NULL;
320	pca.flags = TOCONS | TOLOG;
321	pca.pri = -1;
322	retval = kvprintf(fmt, putchar, &pca, 10, ap);
323	if (!panicstr)
324		msgbuftrigger = 1;
325	consintr = savintr;		/* reenable interrupts */
326	return (retval);
327}
328
329/*
330 * Print a character on console or users terminal.  If destination is
331 * the console then the last bunch of characters are saved in msgbuf for
332 * inspection later.
333 */
334static void
335putchar(int c, void *arg)
336{
337	struct putchar_arg *ap = (struct putchar_arg*) arg;
338	int flags = ap->flags;
339	struct tty *tp = ap->tty;
340	if (panicstr)
341		constty = NULL;
342	if ((flags & TOCONS) && tp == NULL && constty) {
343		tp = constty;
344		flags |= TOTTY;
345	}
346	if ((flags & TOTTY) && tp && tputchar(c, tp) < 0 &&
347	    (flags & TOCONS) && tp == constty)
348		constty = NULL;
349	if ((flags & TOLOG))
350		msglogchar(c, ap->pri);
351	if ((flags & TOCONS) && constty == NULL && c != '\0')
352		(*v_putc)(c);
353}
354
355/*
356 * Scaled down version of sprintf(3).
357 */
358int
359sprintf(char *buf, const char *cfmt, ...)
360{
361	int retval;
362	va_list ap;
363
364	va_start(ap, cfmt);
365	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
366	buf[retval] = '\0';
367	va_end(ap);
368	return (retval);
369}
370
371/*
372 * Scaled down version of vsprintf(3).
373 */
374int
375vsprintf(char *buf, const char *cfmt, va_list ap)
376{
377	int retval;
378
379	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
380	buf[retval] = '\0';
381	return (retval);
382}
383
384/*
385 * Scaled down version of snprintf(3).
386 */
387int
388snprintf(char *str, size_t size, const char *format, ...)
389{
390	int retval;
391	va_list ap;
392
393	va_start(ap, format);
394	retval = vsnprintf(str, size, format, ap);
395	va_end(ap);
396	return(retval);
397}
398
399/*
400 * Scaled down version of vsnprintf(3).
401 */
402int
403vsnprintf(char *str, size_t size, const char *format, va_list ap)
404{
405	struct snprintf_arg info;
406	int retval;
407
408	info.str = str;
409	info.remain = size;
410	retval = kvprintf(format, snprintf_func, &info, 10, ap);
411	if (info.remain >= 1)
412		*info.str++ = '\0';
413	return (retval);
414}
415
416/*
417 * Kernel version which takes radix argument vsnprintf(3).
418 */
419int
420vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
421{
422	struct snprintf_arg info;
423	int retval;
424
425	info.str = str;
426	info.remain = size;
427	retval = kvprintf(format, snprintf_func, &info, radix, ap);
428	if (info.remain >= 1)
429		*info.str++ = '\0';
430	return (retval);
431}
432
433static void
434snprintf_func(int ch, void *arg)
435{
436	struct snprintf_arg *const info = arg;
437
438	if (info->remain >= 2) {
439		*info->str++ = ch;
440		info->remain--;
441	}
442}
443
444/*
445 * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
446 * order; return an optional length and a pointer to the last character
447 * written in the buffer (i.e., the first character of the string).
448 * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
449 */
450static char *
451ksprintn(char *nbuf, uintmax_t num, int base, int *lenp)
452{
453	char *p;
454
455	p = nbuf;
456	*p = '\0';
457	do {
458		*++p = hex2ascii(num % base);
459	} while (num /= base);
460	if (lenp)
461		*lenp = p - nbuf;
462	return (p);
463}
464
465/*
466 * Scaled down version of printf(3).
467 *
468 * Two additional formats:
469 *
470 * The format %b is supported to decode error registers.
471 * Its usage is:
472 *
473 *	printf("reg=%b\n", regval, "<base><arg>*");
474 *
475 * where <base> is the output base expressed as a control character, e.g.
476 * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
477 * the first of which gives the bit number to be inspected (origin 1), and
478 * the next characters (up to a control character, i.e. a character <= 32),
479 * give the name of the register.  Thus:
480 *
481 *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
482 *
483 * would produce output:
484 *
485 *	reg=3<BITTWO,BITONE>
486 *
487 * XXX:  %D  -- Hexdump, takes pointer and separator string:
488 *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
489 *		("%*D", len, ptr, " " -> XX XX XX XX ...
490 */
491int
492kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
493{
494#define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
495	char nbuf[MAXNBUF];
496	char *d;
497	const char *p, *percent, *q;
498	u_char *up;
499	int ch, n;
500	uintmax_t num;
501	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
502	int jflag, tflag, zflag;
503	int dwidth;
504	char padc;
505	int retval = 0;
506
507	num = 0;
508	if (!func)
509		d = (char *) arg;
510	else
511		d = NULL;
512
513	if (fmt == NULL)
514		fmt = "(fmt null)\n";
515
516	if (radix < 2 || radix > 36)
517		radix = 10;
518
519	for (;;) {
520		padc = ' ';
521		width = 0;
522		while ((ch = (u_char)*fmt++) != '%') {
523			if (ch == '\0')
524				return (retval);
525			PCHAR(ch);
526		}
527		percent = fmt - 1;
528		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
529		sign = 0; dot = 0; dwidth = 0;
530		jflag = 0; tflag = 0; zflag = 0;
531reswitch:	switch (ch = (u_char)*fmt++) {
532		case '.':
533			dot = 1;
534			goto reswitch;
535		case '#':
536			sharpflag = 1;
537			goto reswitch;
538		case '+':
539			sign = 1;
540			goto reswitch;
541		case '-':
542			ladjust = 1;
543			goto reswitch;
544		case '%':
545			PCHAR(ch);
546			break;
547		case '*':
548			if (!dot) {
549				width = va_arg(ap, int);
550				if (width < 0) {
551					ladjust = !ladjust;
552					width = -width;
553				}
554			} else {
555				dwidth = va_arg(ap, int);
556			}
557			goto reswitch;
558		case '0':
559			if (!dot) {
560				padc = '0';
561				goto reswitch;
562			}
563		case '1': case '2': case '3': case '4':
564		case '5': case '6': case '7': case '8': case '9':
565				for (n = 0;; ++fmt) {
566					n = n * 10 + ch - '0';
567					ch = *fmt;
568					if (ch < '0' || ch > '9')
569						break;
570				}
571			if (dot)
572				dwidth = n;
573			else
574				width = n;
575			goto reswitch;
576		case 'b':
577			num = (u_int)va_arg(ap, int);
578			p = va_arg(ap, char *);
579			for (q = ksprintn(nbuf, num, *p++, NULL); *q;)
580				PCHAR(*q--);
581
582			if (num == 0)
583				break;
584
585			for (tmp = 0; *p;) {
586				n = *p++;
587				if (num & (1 << (n - 1))) {
588					PCHAR(tmp ? ',' : '<');
589					for (; (n = *p) > ' '; ++p)
590						PCHAR(n);
591					tmp = 1;
592				} else
593					for (; *p > ' '; ++p)
594						continue;
595			}
596			if (tmp)
597				PCHAR('>');
598			break;
599		case 'c':
600			PCHAR(va_arg(ap, int));
601			break;
602		case 'D':
603			up = va_arg(ap, u_char *);
604			p = va_arg(ap, char *);
605			if (!width)
606				width = 16;
607			while(width--) {
608				PCHAR(hex2ascii(*up >> 4));
609				PCHAR(hex2ascii(*up & 0x0f));
610				up++;
611				if (width)
612					for (q=p;*q;q++)
613						PCHAR(*q);
614			}
615			break;
616		case 'd':
617		case 'i':
618			base = 10;
619			sign = 1;
620			goto handle_sign;
621		case 'j':
622			jflag = 1;
623			goto reswitch;
624		case 'l':
625			if (lflag) {
626				lflag = 0;
627				qflag = 1;
628			} else
629				lflag = 1;
630			goto reswitch;
631		case 'n':
632			if (jflag)
633				*(va_arg(ap, intmax_t *)) = retval;
634			else if (qflag)
635				*(va_arg(ap, quad_t *)) = retval;
636			else if (lflag)
637				*(va_arg(ap, long *)) = retval;
638			else if (zflag)
639				*(va_arg(ap, size_t *)) = retval;
640			else
641				*(va_arg(ap, int *)) = retval;
642			break;
643		case 'o':
644			base = 8;
645			goto handle_nosign;
646		case 'p':
647			base = 16;
648			sharpflag = (width == 0);
649			sign = 0;
650			num = (uintptr_t)va_arg(ap, void *);
651			goto number;
652		case 'q':
653			qflag = 1;
654			goto reswitch;
655		case 'r':
656			base = radix;
657			if (sign)
658				goto handle_sign;
659			goto handle_nosign;
660		case 's':
661			p = va_arg(ap, char *);
662			if (p == NULL)
663				p = "(null)";
664			if (!dot)
665				n = strlen (p);
666			else
667				for (n = 0; n < dwidth && p[n]; n++)
668					continue;
669
670			width -= n;
671
672			if (!ladjust && width > 0)
673				while (width--)
674					PCHAR(padc);
675			while (n--)
676				PCHAR(*p++);
677			if (ladjust && width > 0)
678				while (width--)
679					PCHAR(padc);
680			break;
681		case 't':
682			tflag = 1;
683			goto reswitch;
684		case 'u':
685			base = 10;
686			goto handle_nosign;
687		case 'x':
688		case 'X':
689			base = 16;
690			goto handle_nosign;
691		case 'y':
692			base = 16;
693			sign = 1;
694			goto handle_sign;
695		case 'z':
696			zflag = 1;
697			goto reswitch;
698handle_nosign:
699			sign = 0;
700			if (jflag)
701				num = va_arg(ap, uintmax_t);
702			else if (qflag)
703				num = va_arg(ap, u_quad_t);
704			else if (tflag)
705				num = va_arg(ap, ptrdiff_t);
706			else if (lflag)
707				num = va_arg(ap, u_long);
708			else if (zflag)
709				num = va_arg(ap, size_t);
710			else
711				num = va_arg(ap, u_int);
712			goto number;
713handle_sign:
714			if (jflag)
715				num = va_arg(ap, intmax_t);
716			else if (qflag)
717				num = va_arg(ap, quad_t);
718			else if (tflag)
719				num = va_arg(ap, ptrdiff_t);
720			else if (lflag)
721				num = va_arg(ap, long);
722			else if (zflag)
723				num = va_arg(ap, size_t);
724			else
725				num = va_arg(ap, int);
726number:
727			if (sign && (intmax_t)num < 0) {
728				neg = 1;
729				num = -(intmax_t)num;
730			}
731			p = ksprintn(nbuf, num, base, &tmp);
732			if (sharpflag && num != 0) {
733				if (base == 8)
734					tmp++;
735				else if (base == 16)
736					tmp += 2;
737			}
738			if (neg)
739				tmp++;
740
741			if (!ladjust && width && (width -= tmp) > 0)
742				while (width--)
743					PCHAR(padc);
744			if (neg)
745				PCHAR('-');
746			if (sharpflag && num != 0) {
747				if (base == 8) {
748					PCHAR('0');
749				} else if (base == 16) {
750					PCHAR('0');
751					PCHAR('x');
752				}
753			}
754
755			while (*p)
756				PCHAR(*p--);
757
758			if (ladjust && width && (width -= tmp) > 0)
759				while (width--)
760					PCHAR(padc);
761
762			break;
763		default:
764			while (percent < fmt)
765				PCHAR(*percent++);
766			break;
767		}
768	}
769#undef PCHAR
770}
771
772/*
773 * Put character in log buffer with a particular priority.
774 */
775static void
776msglogchar(int c, int pri)
777{
778	static int lastpri = -1;
779	static int dangling;
780	char nbuf[MAXNBUF];
781	char *p;
782
783	if (!msgbufmapped)
784		return;
785	if (c == '\0' || c == '\r')
786		return;
787	if (pri != -1 && pri != lastpri) {
788		if (dangling) {
789			msgbuf_addchar(msgbufp, '\n');
790			dangling = 0;
791		}
792		msgbuf_addchar(msgbufp, '<');
793		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL); *p;)
794			msgbuf_addchar(msgbufp, *p--);
795		msgbuf_addchar(msgbufp, '>');
796		lastpri = pri;
797	}
798	msgbuf_addchar(msgbufp, c);
799	if (c == '\n') {
800		dangling = 0;
801		lastpri = -1;
802	} else {
803		dangling = 1;
804	}
805}
806
807void
808msgbufinit(void *ptr, int size)
809{
810	char *cp;
811	static struct msgbuf *oldp = NULL;
812
813	size -= sizeof(*msgbufp);
814	cp = (char *)ptr;
815	msgbufp = (struct msgbuf *)(cp + size);
816	msgbuf_reinit(msgbufp, cp, size);
817	if (msgbufmapped && oldp != msgbufp)
818		msgbuf_copy(oldp, msgbufp);
819	msgbufmapped = 1;
820	oldp = msgbufp;
821}
822
823SYSCTL_DECL(_security_bsd);
824
825static int unprivileged_read_msgbuf = 1;
826SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_read_msgbuf,
827    CTLFLAG_RW, &unprivileged_read_msgbuf, 0,
828    "Unprivileged processes may read the kernel message buffer");
829
830/* Sysctls for accessing/clearing the msgbuf */
831static int
832sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
833{
834	char buf[128];
835	u_int seq;
836	int error, len;
837
838	if (!unprivileged_read_msgbuf) {
839		error = suser(req->td);
840		if (error)
841			return (error);
842	}
843
844	/* Read the whole buffer, one chunk at a time. */
845	msgbuf_peekbytes(msgbufp, NULL, 0, &seq);
846	while ((len = msgbuf_peekbytes(msgbufp, buf, sizeof(buf), &seq)) > 0) {
847		error = sysctl_handle_opaque(oidp, buf, len, req);
848		if (error)
849			return (error);
850	}
851	return (0);
852}
853
854SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
855    0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
856
857static int msgbuf_clearflag;
858
859static int
860sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
861{
862	int error;
863	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
864	if (!error && req->newptr) {
865		msgbuf_clear(msgbufp);
866		msgbuf_clearflag = 0;
867	}
868	return (error);
869}
870
871SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
872    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clearflag, 0,
873    sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
874
875#ifdef DDB
876
877DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
878{
879	int i, j;
880
881	if (!msgbufmapped) {
882		db_printf("msgbuf not mapped yet\n");
883		return;
884	}
885	db_printf("msgbufp = %p\n", msgbufp);
886	db_printf("magic = %x, size = %d, r= %u, w = %u, ptr = %p, cksum= %u\n",
887	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_rseq,
888	    msgbufp->msg_wseq, msgbufp->msg_ptr, msgbufp->msg_cksum);
889	for (i = 0; i < msgbufp->msg_size; i++) {
890		j = MSGBUF_SEQ_TO_POS(msgbufp, i + msgbufp->msg_rseq);
891		db_printf("%c", msgbufp->msg_ptr[j]);
892	}
893	db_printf("\n");
894}
895
896#endif /* DDB */
897