xref: /freebsd/sys/kern/subr_prf.c (revision d2387d42b8da231a5b95cbc313825fb2aadf26f6)
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("$FreeBSD$");
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 
79 struct putchar_arg {
80 	int	flags;
81 	int	pri;
82 	struct	tty *tty;
83 };
84 
85 struct snprintf_arg {
86 	char	*str;
87 	size_t	remain;
88 };
89 
90 extern	int log_open;
91 
92 static void  msglogchar(int c, int pri);
93 static void  putchar(int ch, void *arg);
94 static char *ksprintn(char *nbuf, uintmax_t num, int base, int *len);
95 static void  snprintf_func(int ch, void *arg);
96 
97 static int consintr = 1;		/* Ok to handle console interrupts? */
98 static int msgbufmapped;		/* Set when safe to use msgbuf */
99 int msgbuftrigger;
100 
101 static int      log_console_output = 1;
102 TUNABLE_INT("kern.log_console_output", &log_console_output);
103 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
104     &log_console_output, 0, "");
105 
106 /*
107  * Warn that a system table is full.
108  */
109 void
110 tablefull(const char *tab)
111 {
112 
113 	log(LOG_ERR, "%s: table is full\n", tab);
114 }
115 
116 /*
117  * Uprintf prints to the controlling terminal for the current process.
118  * It may block if the tty queue is overfull.  No message is printed if
119  * the queue does not clear in a reasonable time.
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 	p = td->td_proc;
134 	PROC_LOCK(p);
135 	if ((p->p_flag & P_CONTROLT) == 0) {
136 		PROC_UNLOCK(p);
137 		return (0);
138 	}
139 	SESS_LOCK(p->p_session);
140 	pca.tty = p->p_session->s_ttyp;
141 	SESS_UNLOCK(p->p_session);
142 	PROC_UNLOCK(p);
143 	if (pca.tty == NULL)
144 		return (0);
145 	pca.flags = TOTTY;
146 	va_start(ap, fmt);
147 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
148 	va_end(ap);
149 
150 	return (retval);
151 }
152 
153 /*
154  * tprintf prints on the controlling terminal associated
155  * with the given session, possibly to the log as well.
156  */
157 void
158 tprintf(struct proc *p, int pri, const char *fmt, ...)
159 {
160 	struct tty *tp = NULL;
161 	int flags = 0;
162 	va_list ap;
163 	struct putchar_arg pca;
164 	struct session *sess = NULL;
165 
166 	if (pri != -1)
167 		flags |= TOLOG;
168 	if (p != NULL) {
169 		PROC_LOCK(p);
170 		if (p->p_flag & P_CONTROLT && p->p_session->s_ttyvp) {
171 			sess = p->p_session;
172 			SESS_LOCK(sess);
173 			PROC_UNLOCK(p);
174 			SESSHOLD(sess);
175 			tp = sess->s_ttyp;
176 			SESS_UNLOCK(sess);
177 			if (ttycheckoutq(tp, 0))
178 				flags |= TOTTY;
179 			else
180 				tp = NULL;
181 		} else
182 			PROC_UNLOCK(p);
183 	}
184 	pca.pri = pri;
185 	pca.tty = tp;
186 	pca.flags = flags;
187 	va_start(ap, fmt);
188 	kvprintf(fmt, putchar, &pca, 10, ap);
189 	va_end(ap);
190 	if (sess != NULL) {
191 		SESS_LOCK(sess);
192 		SESSRELE(sess);
193 		SESS_UNLOCK(sess);
194 	}
195 	msgbuftrigger = 1;
196 }
197 
198 /*
199  * Ttyprintf displays a message on a tty; it should be used only by
200  * the tty driver, or anything that knows the underlying tty will not
201  * be revoke(2)'d away.  Other callers should use tprintf.
202  */
203 int
204 ttyprintf(struct tty *tp, const char *fmt, ...)
205 {
206 	va_list ap;
207 	struct putchar_arg pca;
208 	int retval;
209 
210 	va_start(ap, fmt);
211 	pca.tty = tp;
212 	pca.flags = TOTTY;
213 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
214 	va_end(ap);
215 	return (retval);
216 }
217 
218 /*
219  * Log writes to the log buffer, and guarantees not to sleep (so can be
220  * called by interrupt routines).  If there is no process reading the
221  * log yet, it writes to the console also.
222  */
223 void
224 log(int level, const char *fmt, ...)
225 {
226 	va_list ap;
227 	struct putchar_arg pca;
228 
229 	pca.tty = NULL;
230 	pca.pri = level;
231 	pca.flags = log_open ? TOLOG : TOCONS;
232 
233 	va_start(ap, fmt);
234 	kvprintf(fmt, putchar, &pca, 10, ap);
235 	va_end(ap);
236 
237 	msgbuftrigger = 1;
238 }
239 
240 #define CONSCHUNK 128
241 
242 void
243 log_console(struct uio *uio)
244 {
245 	int c, i, error, iovlen, nl;
246 	struct uio muio;
247 	struct iovec *miov = NULL;
248 	char *consbuffer;
249 	int pri;
250 
251 	if (!log_console_output)
252 		return;
253 
254 	pri = LOG_INFO | LOG_CONSOLE;
255 	muio = *uio;
256 	iovlen = uio->uio_iovcnt * sizeof (struct iovec);
257 	MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
258 	MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
259 	bcopy(muio.uio_iov, miov, iovlen);
260 	muio.uio_iov = miov;
261 	uio = &muio;
262 
263 	nl = 0;
264 	while (uio->uio_resid > 0) {
265 		c = imin(uio->uio_resid, CONSCHUNK);
266 		error = uiomove(consbuffer, c, uio);
267 		if (error != 0)
268 			break;
269 		for (i = 0; i < c; i++) {
270 			msglogchar(consbuffer[i], pri);
271 			if (consbuffer[i] == '\n')
272 				nl = 1;
273 			else
274 				nl = 0;
275 		}
276 	}
277 	if (!nl)
278 		msglogchar('\n', pri);
279 	msgbuftrigger = 1;
280 	FREE(miov, M_TEMP);
281 	FREE(consbuffer, M_TEMP);
282 	return;
283 }
284 
285 int
286 printf(const char *fmt, ...)
287 {
288 	va_list ap;
289 	int savintr;
290 	struct putchar_arg pca;
291 	int retval;
292 
293 	savintr = consintr;		/* disable interrupts */
294 	consintr = 0;
295 	va_start(ap, fmt);
296 	pca.tty = NULL;
297 	pca.flags = TOCONS | TOLOG;
298 	pca.pri = -1;
299 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
300 	va_end(ap);
301 	if (!panicstr)
302 		msgbuftrigger = 1;
303 	consintr = savintr;		/* reenable interrupts */
304 	return (retval);
305 }
306 
307 int
308 vprintf(const char *fmt, va_list ap)
309 {
310 	int savintr;
311 	struct putchar_arg pca;
312 	int retval;
313 
314 	savintr = consintr;		/* disable interrupts */
315 	consintr = 0;
316 	pca.tty = NULL;
317 	pca.flags = TOCONS | TOLOG;
318 	pca.pri = -1;
319 	retval = kvprintf(fmt, putchar, &pca, 10, ap);
320 	if (!panicstr)
321 		msgbuftrigger = 1;
322 	consintr = savintr;		/* reenable interrupts */
323 	return (retval);
324 }
325 
326 /*
327  * Print a character on console or users terminal.  If destination is
328  * the console then the last bunch of characters are saved in msgbuf for
329  * inspection later.
330  */
331 static void
332 putchar(int c, void *arg)
333 {
334 	struct putchar_arg *ap = (struct putchar_arg*) arg;
335 	struct tty *tp = ap->tty;
336 	int consdirect, flags = ap->flags;
337 
338 	consdirect = ((flags & TOCONS) && constty == NULL);
339 	/* Don't use the tty code after a panic or while in ddb. */
340 	if (panicstr)
341 		consdirect = 1;
342 #ifdef DDB
343 	if (db_active)
344 		consdirect = 1;
345 #endif
346 	if (consdirect) {
347 		if (c != '\0')
348 			cnputc(c);
349 	} else {
350 		if ((flags & TOTTY) && tp != NULL)
351 			tputchar(c, tp);
352 		if ((flags & TOCONS) && constty != NULL)
353 			msgbuf_addchar(&consmsgbuf, c);
354 	}
355 	if ((flags & TOLOG))
356 		msglogchar(c, ap->pri);
357 }
358 
359 /*
360  * Scaled down version of sprintf(3).
361  */
362 int
363 sprintf(char *buf, const char *cfmt, ...)
364 {
365 	int retval;
366 	va_list ap;
367 
368 	va_start(ap, cfmt);
369 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
370 	buf[retval] = '\0';
371 	va_end(ap);
372 	return (retval);
373 }
374 
375 /*
376  * Scaled down version of vsprintf(3).
377  */
378 int
379 vsprintf(char *buf, const char *cfmt, va_list ap)
380 {
381 	int retval;
382 
383 	retval = kvprintf(cfmt, NULL, (void *)buf, 10, ap);
384 	buf[retval] = '\0';
385 	return (retval);
386 }
387 
388 /*
389  * Scaled down version of snprintf(3).
390  */
391 int
392 snprintf(char *str, size_t size, const char *format, ...)
393 {
394 	int retval;
395 	va_list ap;
396 
397 	va_start(ap, format);
398 	retval = vsnprintf(str, size, format, ap);
399 	va_end(ap);
400 	return(retval);
401 }
402 
403 /*
404  * Scaled down version of vsnprintf(3).
405  */
406 int
407 vsnprintf(char *str, size_t size, const char *format, va_list ap)
408 {
409 	struct snprintf_arg info;
410 	int retval;
411 
412 	info.str = str;
413 	info.remain = size;
414 	retval = kvprintf(format, snprintf_func, &info, 10, ap);
415 	if (info.remain >= 1)
416 		*info.str++ = '\0';
417 	return (retval);
418 }
419 
420 /*
421  * Kernel version which takes radix argument vsnprintf(3).
422  */
423 int
424 vsnrprintf(char *str, size_t size, int radix, const char *format, va_list ap)
425 {
426 	struct snprintf_arg info;
427 	int retval;
428 
429 	info.str = str;
430 	info.remain = size;
431 	retval = kvprintf(format, snprintf_func, &info, radix, ap);
432 	if (info.remain >= 1)
433 		*info.str++ = '\0';
434 	return (retval);
435 }
436 
437 static void
438 snprintf_func(int ch, void *arg)
439 {
440 	struct snprintf_arg *const info = arg;
441 
442 	if (info->remain >= 2) {
443 		*info->str++ = ch;
444 		info->remain--;
445 	}
446 }
447 
448 /*
449  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
450  * order; return an optional length and a pointer to the last character
451  * written in the buffer (i.e., the first character of the string).
452  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
453  */
454 static char *
455 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp)
456 {
457 	char *p;
458 
459 	p = nbuf;
460 	*p = '\0';
461 	do {
462 		*++p = hex2ascii(num % base);
463 	} while (num /= base);
464 	if (lenp)
465 		*lenp = p - nbuf;
466 	return (p);
467 }
468 
469 /*
470  * Scaled down version of printf(3).
471  *
472  * Two additional formats:
473  *
474  * The format %b is supported to decode error registers.
475  * Its usage is:
476  *
477  *	printf("reg=%b\n", regval, "<base><arg>*");
478  *
479  * where <base> is the output base expressed as a control character, e.g.
480  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
481  * the first of which gives the bit number to be inspected (origin 1), and
482  * the next characters (up to a control character, i.e. a character <= 32),
483  * give the name of the register.  Thus:
484  *
485  *	kvprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
486  *
487  * would produce output:
488  *
489  *	reg=3<BITTWO,BITONE>
490  *
491  * XXX:  %D  -- Hexdump, takes pointer and separator string:
492  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
493  *		("%*D", len, ptr, " " -> XX XX XX XX ...
494  */
495 int
496 kvprintf(char const *fmt, void (*func)(int, void*), void *arg, int radix, va_list ap)
497 {
498 #define PCHAR(c) {int cc=(c); if (func) (*func)(cc,arg); else *d++ = cc; retval++; }
499 	char nbuf[MAXNBUF];
500 	char *d;
501 	const char *p, *percent, *q;
502 	u_char *up;
503 	int ch, n;
504 	uintmax_t num;
505 	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
506 	int cflag, hflag, jflag, tflag, zflag;
507 	int dwidth;
508 	char padc;
509 	int retval = 0;
510 
511 	num = 0;
512 	if (!func)
513 		d = (char *) arg;
514 	else
515 		d = NULL;
516 
517 	if (fmt == NULL)
518 		fmt = "(fmt null)\n";
519 
520 	if (radix < 2 || radix > 36)
521 		radix = 10;
522 
523 	for (;;) {
524 		padc = ' ';
525 		width = 0;
526 		while ((ch = (u_char)*fmt++) != '%') {
527 			if (ch == '\0')
528 				return (retval);
529 			PCHAR(ch);
530 		}
531 		percent = fmt - 1;
532 		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
533 		sign = 0; dot = 0; dwidth = 0;
534 		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
535 reswitch:	switch (ch = (u_char)*fmt++) {
536 		case '.':
537 			dot = 1;
538 			goto reswitch;
539 		case '#':
540 			sharpflag = 1;
541 			goto reswitch;
542 		case '+':
543 			sign = 1;
544 			goto reswitch;
545 		case '-':
546 			ladjust = 1;
547 			goto reswitch;
548 		case '%':
549 			PCHAR(ch);
550 			break;
551 		case '*':
552 			if (!dot) {
553 				width = va_arg(ap, int);
554 				if (width < 0) {
555 					ladjust = !ladjust;
556 					width = -width;
557 				}
558 			} else {
559 				dwidth = va_arg(ap, int);
560 			}
561 			goto reswitch;
562 		case '0':
563 			if (!dot) {
564 				padc = '0';
565 				goto reswitch;
566 			}
567 		case '1': case '2': case '3': case '4':
568 		case '5': case '6': case '7': case '8': case '9':
569 				for (n = 0;; ++fmt) {
570 					n = n * 10 + ch - '0';
571 					ch = *fmt;
572 					if (ch < '0' || ch > '9')
573 						break;
574 				}
575 			if (dot)
576 				dwidth = n;
577 			else
578 				width = n;
579 			goto reswitch;
580 		case 'b':
581 			num = (u_int)va_arg(ap, int);
582 			p = va_arg(ap, char *);
583 			for (q = ksprintn(nbuf, num, *p++, NULL); *q;)
584 				PCHAR(*q--);
585 
586 			if (num == 0)
587 				break;
588 
589 			for (tmp = 0; *p;) {
590 				n = *p++;
591 				if (num & (1 << (n - 1))) {
592 					PCHAR(tmp ? ',' : '<');
593 					for (; (n = *p) > ' '; ++p)
594 						PCHAR(n);
595 					tmp = 1;
596 				} else
597 					for (; *p > ' '; ++p)
598 						continue;
599 			}
600 			if (tmp)
601 				PCHAR('>');
602 			break;
603 		case 'c':
604 			PCHAR(va_arg(ap, int));
605 			break;
606 		case 'D':
607 			up = va_arg(ap, u_char *);
608 			p = va_arg(ap, char *);
609 			if (!width)
610 				width = 16;
611 			while(width--) {
612 				PCHAR(hex2ascii(*up >> 4));
613 				PCHAR(hex2ascii(*up & 0x0f));
614 				up++;
615 				if (width)
616 					for (q=p;*q;q++)
617 						PCHAR(*q);
618 			}
619 			break;
620 		case 'd':
621 		case 'i':
622 			base = 10;
623 			sign = 1;
624 			goto handle_sign;
625 		case 'h':
626 			if (hflag) {
627 				hflag = 0;
628 				cflag = 1;
629 			} else
630 				hflag = 1;
631 			goto reswitch;
632 		case 'j':
633 			jflag = 1;
634 			goto reswitch;
635 		case 'l':
636 			if (lflag) {
637 				lflag = 0;
638 				qflag = 1;
639 			} else
640 				lflag = 1;
641 			goto reswitch;
642 		case 'n':
643 			if (jflag)
644 				*(va_arg(ap, intmax_t *)) = retval;
645 			else if (qflag)
646 				*(va_arg(ap, quad_t *)) = retval;
647 			else if (lflag)
648 				*(va_arg(ap, long *)) = retval;
649 			else if (zflag)
650 				*(va_arg(ap, size_t *)) = retval;
651 			else if (hflag)
652 				*(va_arg(ap, short *)) = retval;
653 			else if (cflag)
654 				*(va_arg(ap, char *)) = retval;
655 			else
656 				*(va_arg(ap, int *)) = retval;
657 			break;
658 		case 'o':
659 			base = 8;
660 			goto handle_nosign;
661 		case 'p':
662 			base = 16;
663 			sharpflag = (width == 0);
664 			sign = 0;
665 			num = (uintptr_t)va_arg(ap, void *);
666 			goto number;
667 		case 'q':
668 			qflag = 1;
669 			goto reswitch;
670 		case 'r':
671 			base = radix;
672 			if (sign)
673 				goto handle_sign;
674 			goto handle_nosign;
675 		case 's':
676 			p = va_arg(ap, char *);
677 			if (p == NULL)
678 				p = "(null)";
679 			if (!dot)
680 				n = strlen (p);
681 			else
682 				for (n = 0; n < dwidth && p[n]; n++)
683 					continue;
684 
685 			width -= n;
686 
687 			if (!ladjust && width > 0)
688 				while (width--)
689 					PCHAR(padc);
690 			while (n--)
691 				PCHAR(*p++);
692 			if (ladjust && width > 0)
693 				while (width--)
694 					PCHAR(padc);
695 			break;
696 		case 't':
697 			tflag = 1;
698 			goto reswitch;
699 		case 'u':
700 			base = 10;
701 			goto handle_nosign;
702 		case 'x':
703 		case 'X':
704 			base = 16;
705 			goto handle_nosign;
706 		case 'y':
707 			base = 16;
708 			sign = 1;
709 			goto handle_sign;
710 		case 'z':
711 			zflag = 1;
712 			goto reswitch;
713 handle_nosign:
714 			sign = 0;
715 			if (jflag)
716 				num = va_arg(ap, uintmax_t);
717 			else if (qflag)
718 				num = va_arg(ap, u_quad_t);
719 			else if (tflag)
720 				num = va_arg(ap, ptrdiff_t);
721 			else if (lflag)
722 				num = va_arg(ap, u_long);
723 			else if (zflag)
724 				num = va_arg(ap, size_t);
725 			else if (hflag)
726 				num = (u_short)va_arg(ap, int);
727 			else if (cflag)
728 				num = (u_char)va_arg(ap, int);
729 			else
730 				num = va_arg(ap, u_int);
731 			goto number;
732 handle_sign:
733 			if (jflag)
734 				num = va_arg(ap, intmax_t);
735 			else if (qflag)
736 				num = va_arg(ap, quad_t);
737 			else if (tflag)
738 				num = va_arg(ap, ptrdiff_t);
739 			else if (lflag)
740 				num = va_arg(ap, long);
741 			else if (zflag)
742 				num = va_arg(ap, size_t);
743 			else if (hflag)
744 				num = (short)va_arg(ap, int);
745 			else if (cflag)
746 				num = (char)va_arg(ap, int);
747 			else
748 				num = va_arg(ap, int);
749 number:
750 			if (sign && (intmax_t)num < 0) {
751 				neg = 1;
752 				num = -(intmax_t)num;
753 			}
754 			p = ksprintn(nbuf, num, base, &tmp);
755 			if (sharpflag && num != 0) {
756 				if (base == 8)
757 					tmp++;
758 				else if (base == 16)
759 					tmp += 2;
760 			}
761 			if (neg)
762 				tmp++;
763 
764 			if (!ladjust && width && (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 
778 			while (*p)
779 				PCHAR(*p--);
780 
781 			if (ladjust && width && (width -= tmp) > 0)
782 				while (width--)
783 					PCHAR(padc);
784 
785 			break;
786 		default:
787 			while (percent < fmt)
788 				PCHAR(*percent++);
789 			break;
790 		}
791 	}
792 #undef PCHAR
793 }
794 
795 /*
796  * Put character in log buffer with a particular priority.
797  */
798 static void
799 msglogchar(int c, int pri)
800 {
801 	static int lastpri = -1;
802 	static int dangling;
803 	char nbuf[MAXNBUF];
804 	char *p;
805 
806 	if (!msgbufmapped)
807 		return;
808 	if (c == '\0' || c == '\r')
809 		return;
810 	if (pri != -1 && pri != lastpri) {
811 		if (dangling) {
812 			msgbuf_addchar(msgbufp, '\n');
813 			dangling = 0;
814 		}
815 		msgbuf_addchar(msgbufp, '<');
816 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL); *p;)
817 			msgbuf_addchar(msgbufp, *p--);
818 		msgbuf_addchar(msgbufp, '>');
819 		lastpri = pri;
820 	}
821 	msgbuf_addchar(msgbufp, c);
822 	if (c == '\n') {
823 		dangling = 0;
824 		lastpri = -1;
825 	} else {
826 		dangling = 1;
827 	}
828 }
829 
830 void
831 msgbufinit(void *ptr, int size)
832 {
833 	char *cp;
834 	static struct msgbuf *oldp = NULL;
835 
836 	size -= sizeof(*msgbufp);
837 	cp = (char *)ptr;
838 	msgbufp = (struct msgbuf *)(cp + size);
839 	msgbuf_reinit(msgbufp, cp, size);
840 	if (msgbufmapped && oldp != msgbufp)
841 		msgbuf_copy(oldp, msgbufp);
842 	msgbufmapped = 1;
843 	oldp = msgbufp;
844 }
845 
846 SYSCTL_DECL(_security_bsd);
847 
848 static int unprivileged_read_msgbuf = 1;
849 SYSCTL_INT(_security_bsd, OID_AUTO, unprivileged_read_msgbuf,
850     CTLFLAG_RW, &unprivileged_read_msgbuf, 0,
851     "Unprivileged processes may read the kernel message buffer");
852 
853 /* Sysctls for accessing/clearing the msgbuf */
854 static int
855 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
856 {
857 	char buf[128];
858 	u_int seq;
859 	int error, len;
860 
861 	if (!unprivileged_read_msgbuf) {
862 		error = suser(req->td);
863 		if (error)
864 			return (error);
865 	}
866 
867 	/* Read the whole buffer, one chunk at a time. */
868 	msgbuf_peekbytes(msgbufp, NULL, 0, &seq);
869 	while ((len = msgbuf_peekbytes(msgbufp, buf, sizeof(buf), &seq)) > 0) {
870 		error = sysctl_handle_opaque(oidp, buf, len, req);
871 		if (error)
872 			return (error);
873 	}
874 	return (0);
875 }
876 
877 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
878     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
879 
880 static int msgbuf_clearflag;
881 
882 static int
883 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
884 {
885 	int error;
886 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
887 	if (!error && req->newptr) {
888 		msgbuf_clear(msgbufp);
889 		msgbuf_clearflag = 0;
890 	}
891 	return (error);
892 }
893 
894 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
895     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clearflag, 0,
896     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
897 
898 #ifdef DDB
899 
900 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
901 {
902 	int i, j;
903 
904 	if (!msgbufmapped) {
905 		db_printf("msgbuf not mapped yet\n");
906 		return;
907 	}
908 	db_printf("msgbufp = %p\n", msgbufp);
909 	db_printf("magic = %x, size = %d, r= %u, w = %u, ptr = %p, cksum= %u\n",
910 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_rseq,
911 	    msgbufp->msg_wseq, msgbufp->msg_ptr, msgbufp->msg_cksum);
912 	for (i = 0; i < msgbufp->msg_size; i++) {
913 		j = MSGBUF_SEQ_TO_POS(msgbufp, i + msgbufp->msg_rseq);
914 		db_printf("%c", msgbufp->msg_ptr[j]);
915 	}
916 	db_printf("\n");
917 }
918 
919 #endif /* DDB */
920 
921 void
922 hexdump(void *ptr, int length, const char *hdr, int flags)
923 {
924 	int i, j, k;
925 	int cols;
926 	unsigned char *cp;
927 	char delim;
928 
929 	if ((flags & HD_DELIM_MASK) != 0)
930 		delim = (flags & HD_DELIM_MASK) >> 8;
931 	else
932 		delim = ' ';
933 
934 	if ((flags & HD_COLUMN_MASK) != 0)
935 		cols = flags & HD_COLUMN_MASK;
936 	else
937 		cols = 16;
938 
939 	cp = ptr;
940 	for (i = 0; i < length; i+= cols) {
941 		if (hdr != NULL)
942 			printf("%s", hdr);
943 
944 		if ((flags & HD_OMIT_COUNT) == 0)
945 			printf("%04x  ", i);
946 
947 		if ((flags & HD_OMIT_HEX) == 0) {
948 			for (j = 0; j < cols; j++) {
949 				k = i + j;
950 				if (k < length)
951 					printf("%c%02x", delim, cp[k]);
952 				else
953 					printf("   ");
954 			}
955 		}
956 
957 		if ((flags & HD_OMIT_CHARS) == 0) {
958 			printf("  |");
959 			for (j = 0; j < cols; j++) {
960 				k = i + j;
961 				if (k >= length)
962 					printf(" ");
963 				else if (cp[k] >= ' ' && cp[k] <= '~')
964 					printf("%c", cp[k]);
965 				else
966 					printf(".");
967 			}
968 			printf("|\n");
969 		}
970 	}
971 }
972 
973