xref: /dragonfly/sys/kern/subr_prf.c (revision 80e4a0b7)
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. 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  * $FreeBSD: src/sys/kern/subr_prf.c,v 1.61.2.5 2002/08/31 18:22:08 dwmalone Exp $
36  */
37 
38 #include "opt_ddb.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/msgbuf.h>
44 #include <sys/malloc.h>
45 #include <sys/proc.h>
46 #include <sys/priv.h>
47 #include <sys/tty.h>
48 #include <sys/tprintf.h>
49 #include <sys/stdint.h>
50 #include <sys/syslog.h>
51 #include <sys/cons.h>
52 #include <sys/uio.h>
53 #include <sys/sysctl.h>
54 #include <sys/lock.h>
55 #include <sys/ctype.h>
56 #include <sys/eventhandler.h>
57 #include <sys/kthread.h>
58 #include <sys/cpu_topology.h>
59 
60 #include <sys/thread2.h>
61 #include <sys/spinlock2.h>
62 
63 #ifdef DDB
64 #include <ddb/ddb.h>
65 #endif
66 
67 /*
68  * Note that stdarg.h and the ANSI style va_start macro is used for both
69  * ANSI and traditional C compilers.  We use the __ machine version to stay
70  * within the kernel header file set.
71  */
72 #include <machine/stdarg.h>
73 
74 #define TOCONS		0x01
75 #define TOTTY		0x02
76 #define TOLOG		0x04
77 #define TOWAKEUP	0x08
78 #define TONOSPIN	0x10	/* avoid serialization */
79 
80 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
81 #define MAXNBUF	(sizeof(intmax_t) * NBBY + 1)
82 
83 struct putchar_arg {
84 	int	flags;
85 	int	pri;
86 	struct	tty *tty;
87 };
88 
89 struct snprintf_arg {
90 	char	*str;
91 	size_t	remain;
92 };
93 
94 extern	int log_open;
95 
96 struct	tty *constty;			/* pointer to console "window" tty */
97 
98 static void  msglogchar(int c, int pri);
99 static void  msgaddchar(int c, void *dummy);
100 static void  kputchar (int ch, void *arg);
101 static char *ksprintn (char *nbuf, uintmax_t num, int base, int *lenp,
102 		       int upper);
103 static void  snprintf_func (int ch, void *arg);
104 
105 static int consintr = 1;		/* Ok to handle console interrupts? */
106 static int msgbufmapped;		/* Set when safe to use msgbuf */
107 static struct spinlock cons_spin = SPINLOCK_INITIALIZER(cons_spin, "cons_spin");
108 static thread_t constty_td = NULL;
109 
110 int msgbuftrigger;
111 
112 static int      log_console_output = 1;
113 TUNABLE_INT("kern.log_console_output", &log_console_output);
114 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
115     &log_console_output, 0, "");
116 static int	kprintf_logging = TOLOG | TOCONS;
117 SYSCTL_INT(_kern, OID_AUTO, kprintf_logging, CTLFLAG_RW,
118     &kprintf_logging, 0, "");
119 
120 static int ptr_restrict = 0;
121 TUNABLE_INT("security.ptr_restrict", &ptr_restrict);
122 SYSCTL_INT(_security, OID_AUTO, ptr_restrict, CTLFLAG_RW, &ptr_restrict, 0,
123     "Prevent leaking the kernel pointers back to userland");
124 
125 static int unprivileged_read_msgbuf = 1;
126 SYSCTL_INT(_security, OID_AUTO, unprivileged_read_msgbuf, CTLFLAG_RW,
127     &unprivileged_read_msgbuf, 0,
128     "Unprivileged processes may read the kernel message buffer");
129 
130 /*
131  * Warn that a system table is full.
132  */
133 void
134 tablefull(const char *tab)
135 {
136 
137 	log(LOG_ERR, "%s: table is full\n", tab);
138 }
139 
140 /*
141  * Uprintf prints to the controlling terminal for the current process.
142  */
143 int
144 uprintf(const char *fmt, ...)
145 {
146 	struct proc *p = curproc;
147 	__va_list ap;
148 	struct putchar_arg pca;
149 	int retval = 0;
150 
151 	if (p && (p->p_flags & P_CONTROLT) && p->p_session->s_ttyvp) {
152 		__va_start(ap, fmt);
153 		pca.tty = p->p_session->s_ttyp;
154 		pca.flags = TOTTY;
155 
156 		retval = kvcprintf(fmt, kputchar, &pca, ap);
157 		__va_end(ap);
158 	}
159 	return (retval);
160 }
161 
162 tpr_t
163 tprintf_open(struct proc *p)
164 {
165 	if ((p->p_flags & P_CONTROLT) && p->p_session->s_ttyvp) {
166 		sess_hold(p->p_session);
167 		return ((tpr_t) p->p_session);
168 	}
169 	return (NULL);
170 }
171 
172 void
173 tprintf_close(tpr_t sess)
174 {
175 	if (sess)
176 		sess_rele((struct session *) sess);
177 }
178 
179 /*
180  * tprintf prints on the controlling terminal associated
181  * with the given session.
182  */
183 int
184 tprintf(tpr_t tpr, const char *fmt, ...)
185 {
186 	struct session *sess = (struct session *)tpr;
187 	struct tty *tp = NULL;
188 	int flags = TOLOG;
189 	__va_list ap;
190 	struct putchar_arg pca;
191 	int retval;
192 
193 	if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
194 		flags |= TOTTY;
195 		tp = sess->s_ttyp;
196 	}
197 	__va_start(ap, fmt);
198 	pca.tty = tp;
199 	pca.flags = flags;
200 	pca.pri = LOG_INFO;
201 	retval = kvcprintf(fmt, kputchar, &pca, ap);
202 	__va_end(ap);
203 	msgbuftrigger = 1;
204 	return (retval);
205 }
206 
207 /*
208  * Ttyprintf displays a message on a tty; it should be used only by
209  * the tty driver, or anything that knows the underlying tty will not
210  * be revoke(2)'d away.  Other callers should use tprintf.
211  */
212 int
213 ttyprintf(struct tty *tp, const char *fmt, ...)
214 {
215 	__va_list ap;
216 	struct putchar_arg pca;
217 	int retval;
218 
219 	__va_start(ap, fmt);
220 	pca.tty = tp;
221 	pca.flags = TOTTY;
222 	retval = kvcprintf(fmt, kputchar, &pca, ap);
223 	__va_end(ap);
224 	return (retval);
225 }
226 
227 /*
228  * Log writes to the log buffer, and guarantees not to sleep (so can be
229  * called by interrupt routines).  If there is no process reading the
230  * log yet, it writes to the console also.
231  */
232 int
233 log(int level, const char *fmt, ...)
234 {
235 	__va_list ap;
236 	int retval;
237 	struct putchar_arg pca;
238 
239 	pca.tty = NULL;
240 	pca.pri = level;
241 	if ((kprintf_logging & TOCONS) == 0 || log_open)
242 		pca.flags = TOLOG;
243 	else
244 		pca.flags = TOCONS;
245 
246 	__va_start(ap, fmt);
247 	retval = kvcprintf(fmt, kputchar, &pca, ap);
248 	__va_end(ap);
249 
250 	msgbuftrigger = 1;
251 	return (retval);
252 }
253 
254 #define CONSCHUNK 128
255 
256 void
257 log_console(struct uio *uio)
258 {
259 	int c, i, error, iovlen, nl;
260 	struct uio muio;
261 	struct iovec *miov = NULL;
262 	char *consbuffer;
263 	int pri;
264 
265 	if (!log_console_output)
266 		return;
267 
268 	pri = LOG_INFO | LOG_CONSOLE;
269 	muio = *uio;
270 	iovlen = uio->uio_iovcnt * sizeof (struct iovec);
271 	miov = kmalloc(iovlen, M_TEMP, M_WAITOK);
272 	consbuffer = kmalloc(CONSCHUNK, M_TEMP, M_WAITOK);
273 	bcopy((caddr_t)muio.uio_iov, (caddr_t)miov, iovlen);
274 	muio.uio_iov = miov;
275 	uio = &muio;
276 
277 	nl = 0;
278 	while (uio->uio_resid > 0) {
279 		c = (int)szmin(uio->uio_resid, CONSCHUNK);
280 		error = uiomove(consbuffer, (size_t)c, uio);
281 		if (error != 0)
282 			break;
283 		for (i = 0; i < c; i++) {
284 			msglogchar(consbuffer[i], pri);
285 			if (consbuffer[i] == '\n')
286 				nl = 1;
287 			else
288 				nl = 0;
289 		}
290 	}
291 	if (!nl)
292 		msglogchar('\n', pri);
293 	msgbuftrigger = 1;
294 	kfree(miov, M_TEMP);
295 	kfree(consbuffer, M_TEMP);
296 	return;
297 }
298 
299 /*
300  * Output to the console.
301  */
302 int
303 kprintf(const char *fmt, ...)
304 {
305 	__va_list ap;
306 	int savintr;
307 	struct putchar_arg pca;
308 	int retval;
309 
310 	savintr = consintr;		/* disable interrupts */
311 	consintr = 0;
312 	__va_start(ap, fmt);
313 	pca.tty = NULL;
314 	pca.flags = kprintf_logging & ~TOTTY;
315 	pca.pri = -1;
316 	retval = kvcprintf(fmt, kputchar, &pca, ap);
317 	__va_end(ap);
318 	if (!panicstr)
319 		msgbuftrigger = 1;
320 	consintr = savintr;		/* reenable interrupts */
321 	return (retval);
322 }
323 
324 int
325 kvprintf(const char *fmt, __va_list ap)
326 {
327 	int savintr;
328 	struct putchar_arg pca;
329 	int retval;
330 
331 	savintr = consintr;		/* disable interrupts */
332 	consintr = 0;
333 	pca.tty = NULL;
334 	pca.flags = kprintf_logging & ~TOTTY;
335 	pca.pri = -1;
336 	retval = kvcprintf(fmt, kputchar, &pca, ap);
337 	if (!panicstr)
338 		msgbuftrigger = 1;
339 	consintr = savintr;		/* reenable interrupts */
340 	return (retval);
341 }
342 
343 /*
344  * Limited rate kprintf.  The passed rate structure must be initialized
345  * with the desired reporting frequency.  A frequency of 0 will result in
346  * no output.
347  *
348  * count may be initialized to a negative number to allow an initial
349  * burst.
350  */
351 void
352 krateprintf(struct krate *rate, const char *fmt, ...)
353 {
354 	__va_list ap;
355 
356 	if (rate->ticks != (int)time_uptime) {
357 		rate->ticks = (int)time_uptime;
358 		if (rate->count > 0)
359 			rate->count = 0;
360 	}
361 	if (rate->count < rate->freq) {
362 		++rate->count;
363 		__va_start(ap, fmt);
364 		kvprintf(fmt, ap);
365 		__va_end(ap);
366 	}
367 }
368 
369 /*
370  * Print a character to the dmesg log, the console, and/or the user's
371  * terminal.
372  *
373  * NOTE: TOTTY does not require nonblocking operation, but TOCONS
374  * 	 and TOLOG do.  When we have a constty we still output to
375  *	 the real console but we have a monitoring thread which
376  *	 we wakeup which tracks the log.
377  */
378 static void
379 kputchar(int c, void *arg)
380 {
381 	struct putchar_arg *ap = (struct putchar_arg*) arg;
382 	int flags = ap->flags;
383 	struct tty *tp = ap->tty;
384 
385 	if (panicstr)
386 		constty = NULL;
387 	if ((flags & TOCONS) && tp == NULL && constty)
388 		flags |= TOLOG | TOWAKEUP;
389 	if ((flags & TOTTY) && tputchar(c, tp) < 0)
390 		ap->flags &= ~TOTTY;
391 	if ((flags & TOLOG))
392 		msglogchar(c, ap->pri);
393 	if ((flags & TOCONS) && c)
394 		cnputc(c);
395 	if (flags & TOWAKEUP)
396 		wakeup(constty_td);
397 }
398 
399 /*
400  * Scaled down version of sprintf(3).
401  */
402 int
403 ksprintf(char *buf, const char *cfmt, ...)
404 {
405 	int retval;
406 	__va_list ap;
407 
408 	__va_start(ap, cfmt);
409 	retval = kvcprintf(cfmt, NULL, buf, ap);
410 	buf[retval] = '\0';
411 	__va_end(ap);
412 	return (retval);
413 }
414 
415 /*
416  * Scaled down version of vsprintf(3).
417  */
418 int
419 kvsprintf(char *buf, const char *cfmt, __va_list ap)
420 {
421 	int retval;
422 
423 	retval = kvcprintf(cfmt, NULL, buf, ap);
424 	buf[retval] = '\0';
425 	return (retval);
426 }
427 
428 /*
429  * Scaled down version of snprintf(3).
430  */
431 int
432 ksnprintf(char *str, size_t size, const char *format, ...)
433 {
434 	int retval;
435 	__va_list ap;
436 
437 	__va_start(ap, format);
438 	retval = kvsnprintf(str, size, format, ap);
439 	__va_end(ap);
440 	return(retval);
441 }
442 
443 /*
444  * Scaled down version of vsnprintf(3).
445  */
446 int
447 kvsnprintf(char *str, size_t size, const char *format, __va_list ap)
448 {
449 	struct snprintf_arg info;
450 	int retval;
451 
452 	info.str = str;
453 	info.remain = size;
454 	retval = kvcprintf(format, snprintf_func, &info, ap);
455 	if (info.remain >= 1)
456 		*info.str++ = '\0';
457 	return (retval);
458 }
459 
460 int
461 kvasnprintf(char **strp, size_t size, const char *format, __va_list ap)
462 {
463 	struct snprintf_arg info;
464 	int retval;
465 
466 	*strp = kmalloc(size, M_TEMP, M_WAITOK);
467 	info.str = *strp;
468 	info.remain = size;
469 	retval = kvcprintf(format, snprintf_func, &info, ap);
470 	if (info.remain >= 1)
471 		*info.str++ = '\0';
472 	return (retval);
473 }
474 
475 void
476 kvasfree(char **strp)
477 {
478 	if (*strp) {
479 		kfree(*strp, M_TEMP);
480 		*strp = NULL;
481 	}
482 }
483 
484 static void
485 snprintf_func(int ch, void *arg)
486 {
487 	struct snprintf_arg *const info = arg;
488 
489 	if (info->remain >= 2) {
490 		*info->str++ = ch;
491 		info->remain--;
492 	}
493 }
494 
495 /*
496  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
497  * order; return an optional length and a pointer to the last character
498  * written in the buffer (i.e., the first character of the string).
499  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
500  */
501 static char *
502 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
503 {
504 	char *p, c;
505 
506 	p = nbuf;
507 	*p = '\0';
508 	do {
509 		c = hex2ascii(num % base);
510 		*++p = upper ? toupper(c) : c;
511 	} while (num /= base);
512 	if (lenp)
513 		*lenp = p - nbuf;
514 	return (p);
515 }
516 
517 /*
518  * Scaled down version of printf(3).
519  *
520  * Two additional formats:
521  *
522  * The format %pb%i is supported to decode error registers.
523  * Its usage is:
524  *
525  *	kprintf("reg=%pb%i\n", "<base><arg>*", regval);
526  *
527  * where <base> is the output base expressed as a control character, e.g.
528  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
529  * the first of which gives the bit number to be inspected (origin 1), and
530  * the next characters (up to a control character, i.e. a character <= 32),
531  * give the name of the register.  Thus:
532  *
533  *	kvcprintf("reg=%pb%i\n", "\10\2BITTWO\1BITONE\n", 3);
534  *
535  * would produce output:
536  *
537  *	reg=3<BITTWO,BITONE>
538  */
539 
540 #define PCHAR(c) {int cc=(c); if(func) (*func)(cc,arg); else *d++=cc; retval++;}
541 
542 int
543 kvcprintf(char const *fmt, void (*func)(int, void*), void *arg, __va_list ap)
544 {
545 	char nbuf[MAXNBUF];
546 	char *d;
547 	const char *p, *percent, *q;
548 	int ch, n;
549 	uintmax_t num;
550 	int base, tmp, width, ladjust, sharpflag, spaceflag, neg, sign, dot;
551 	int cflag, hflag, jflag, lflag, qflag, tflag, zflag;
552 	int dwidth, upper;
553 	char padc;
554 	int retval = 0, stop = 0;
555 	int usespin;
556 	int ddb_active;
557 
558 	/*
559 	 * Make a supreme effort to avoid reentrant panics or deadlocks.
560 	 *
561 	 * NOTE!  Do nothing that would access mycpu/gd/fs unless the
562 	 *	  function is the normal kputchar(), which allows us to
563 	 *	  use this function for very early debugging with a special
564 	 *	  function.
565 	 */
566 	if (func == kputchar) {
567 		if (mycpu->gd_flags & GDF_KPRINTF)
568 			return(0);
569 		atomic_set_long(&mycpu->gd_flags, GDF_KPRINTF);
570 	}
571 
572 #ifdef DDB
573 	ddb_active = db_active;
574 #else
575 	ddb_active = 0;
576 #endif
577 
578 	num = 0;
579 	if (!func)
580 		d = (char *) arg;
581 	else
582 		d = NULL;
583 
584 	if (fmt == NULL)
585 		fmt = "(fmt null)\n";
586 
587 	usespin = (func == kputchar &&
588 		   (kprintf_logging & TONOSPIN) == 0 &&
589 		   panic_cpu_gd != mycpu &&
590 		   (((struct putchar_arg *)arg)->flags & TOTTY) == 0);
591 	if (usespin) {
592 		crit_enter_hard();
593 		spin_lock(&cons_spin);
594 	}
595 
596 	for (;;) {
597 		padc = ' ';
598 		width = 0;
599 		while ((ch = (u_char)*fmt++) != '%' || stop) {
600 			if (ch == '\0')
601 				goto done;
602 			PCHAR(ch);
603 		}
604 		percent = fmt - 1;
605 		dot = dwidth = ladjust = neg = sharpflag = sign = upper = 0;
606 		spaceflag = 0;
607 		cflag = hflag = jflag = lflag = qflag = tflag = zflag = 0;
608 
609 reswitch:
610 		switch (ch = (u_char)*fmt++) {
611 		case ' ':
612 			spaceflag = 1;
613 			goto reswitch;
614 		case '.':
615 			dot = 1;
616 			goto reswitch;
617 		case '#':
618 			sharpflag = 1;
619 			goto reswitch;
620 		case '+':
621 			sign = 1;
622 			goto reswitch;
623 		case '-':
624 			ladjust = 1;
625 			goto reswitch;
626 		case '%':
627 			PCHAR(ch);
628 			break;
629 		case '*':
630 			if (!dot) {
631 				width = __va_arg(ap, int);
632 				if (width < 0) {
633 					ladjust = !ladjust;
634 					width = -width;
635 				}
636 			} else {
637 				dwidth = __va_arg(ap, int);
638 			}
639 			goto reswitch;
640 		case '0':
641 			if (!dot) {
642 				padc = '0';
643 				goto reswitch;
644 			}
645 		case '1': case '2': case '3': case '4':
646 		case '5': case '6': case '7': case '8': case '9':
647 				for (n = 0;; ++fmt) {
648 					n = n * 10 + ch - '0';
649 					ch = *fmt;
650 					if (ch < '0' || ch > '9')
651 						break;
652 				}
653 			if (dot)
654 				dwidth = n;
655 			else
656 				width = n;
657 			goto reswitch;
658 		case 'c':
659 			PCHAR(__va_arg(ap, int));
660 			break;
661 		case 'd':
662 		case 'i':
663 			base = 10;
664 			sign = 1;
665 			goto handle_sign;
666 		case 'h':
667 			if (hflag) {
668 				hflag = 0;
669 				cflag = 1;
670 			} else
671 				hflag = 1;
672 			goto reswitch;
673 		case 'j':
674 			jflag = 1;
675 			goto reswitch;
676 		case 'l':
677 			if (lflag) {
678 				lflag = 0;
679 				qflag = 1;
680 			} else
681 				lflag = 1;
682 			goto reswitch;
683 		case 'n':
684 			if (cflag)
685 				*(__va_arg(ap, char *)) = retval;
686 			else if (hflag)
687 				*(__va_arg(ap, short *)) = retval;
688 			else if (jflag)
689 				*(__va_arg(ap, intmax_t *)) = retval;
690 			else if (lflag)
691 				*(__va_arg(ap, long *)) = retval;
692 			else if (qflag)
693 				*(__va_arg(ap, quad_t *)) = retval;
694 			else
695 				*(__va_arg(ap, int *)) = retval;
696 			break;
697 		case 'o':
698 			base = 8;
699 			goto handle_nosign;
700 		case 'p':
701 			/* peek if this is a /b/ hiding as /p/ or not */
702 			if (fmt[0] == 'b' && fmt[1] == '%' && fmt[2] == 'i') {
703 				fmt += 3; /* consume "b%i" */
704 				p = __va_arg(ap, char *);
705 				num = (u_int)__va_arg(ap, int);
706 				for (q = ksprintn(nbuf, num, *p++, NULL, 0);*q;)
707 					PCHAR(*q--);
708 
709 				if (num == 0)
710 					break;
711 
712 				for (tmp = 0; *p;) {
713 					n = *p++;
714 					if (num & (1 << (n - 1))) {
715 						PCHAR(tmp ? ',' : '<');
716 						for (; (n = *p) > ' '; ++p)
717 							PCHAR(n);
718 						tmp = 1;
719 					} else {
720 						for (; *p > ' '; ++p)
721 							continue;
722 					}
723 				}
724 				if (tmp)
725 					PCHAR('>');
726 				break;
727 			}
728 			base = 16;
729 			sharpflag = (width == 0);
730 			sign = 0;
731 			num = (uintptr_t)__va_arg(ap, void *);
732 			if (ptr_restrict && fmt[0] != 'x' &&
733 			    !(panicstr || dumping || ddb_active)) {
734 				if (ptr_restrict == 1) {
735 					/* zero out upper bits */
736 					num &= 0xffffffUL;
737 				} else {
738 					num = 0xc0ffee;
739 				}
740 			}
741 			goto number;
742 		case 'q':
743 			qflag = 1;
744 			goto reswitch;
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 			/* FALLTHROUGH */
775 		case 'x':
776 			base = 16;
777 			goto handle_nosign;
778 		case 'z':
779 			zflag = 1;
780 			goto reswitch;
781 handle_nosign:
782 			sign = 0;
783 			if (cflag)
784 				num = (u_char)__va_arg(ap, int);
785 			else if (hflag)
786 				num = (u_short)__va_arg(ap, int);
787 			else if (jflag)
788 				num = __va_arg(ap, uintmax_t);
789 			else if (lflag)
790 				num = __va_arg(ap, u_long);
791 			else if (qflag)
792 				num = __va_arg(ap, u_quad_t);
793 			else if (tflag)
794 				num = __va_arg(ap, ptrdiff_t);
795 			else if (zflag)
796 				num = __va_arg(ap, size_t);
797 			else
798 				num = __va_arg(ap, u_int);
799 			goto number;
800 handle_sign:
801 			if (cflag)
802 				num = (char)__va_arg(ap, int);
803 			else if (hflag)
804 				num = (short)__va_arg(ap, int);
805 			else if (jflag)
806 				num = __va_arg(ap, intmax_t);
807 			else if (lflag)
808 				num = __va_arg(ap, long);
809 			else if (qflag)
810 				num = __va_arg(ap, quad_t);
811 			else if (tflag)
812 				num = __va_arg(ap, ptrdiff_t);
813 			else if (zflag)
814 				num = __va_arg(ap, ssize_t);
815 			else
816 				num = __va_arg(ap, int);
817 number:
818 			if (sign && (intmax_t)num < 0) {
819 				neg = 1;
820 				num = -(intmax_t)num;
821 			}
822 			p = ksprintn(nbuf, num, base, &n, upper);
823 			tmp = 0;
824 			if (sharpflag && num != 0) {
825 				if (base == 8)
826 					tmp++;
827 				else if (base == 16)
828 					tmp += 2;
829 			}
830 			if (neg || (sign && spaceflag))
831 				tmp++;
832 
833 			if (!ladjust && padc == '0')
834 				dwidth = width - tmp;
835 			width -= tmp + imax(dwidth, n);
836 			dwidth -= n;
837 			if (!ladjust)
838 				while (width-- > 0)
839 					PCHAR(' ');
840 			if (neg) {
841 				PCHAR('-');
842 			} else if (sign && spaceflag) {
843 				PCHAR(' ');
844 			}
845 			if (sharpflag && num != 0) {
846 				if (base == 8) {
847 					PCHAR('0');
848 				} else if (base == 16) {
849 					PCHAR('0');
850 					PCHAR('x');
851 				}
852 			}
853 			while (dwidth-- > 0)
854 				PCHAR('0');
855 
856 			while (*p)
857 				PCHAR(*p--);
858 
859 			if (ladjust)
860 				while (width-- > 0)
861 					PCHAR(' ');
862 
863 			break;
864 		default:
865 			while (percent < fmt)
866 				PCHAR(*percent++);
867 			/*
868 			 * Since we ignore an formatting argument it is no
869 			 * longer safe to obey the remaining formatting
870 			 * arguments as the arguments will no longer match
871 			 * the format specs.
872 			 */
873 			stop = 1;
874 			break;
875 		}
876 	}
877 done:
878 	/*
879 	 * Cleanup reentrancy issues.
880 	 */
881 	if (func == kputchar)
882 		atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
883 	if (usespin) {
884 		spin_unlock(&cons_spin);
885 		crit_exit_hard();
886 	}
887 	return (retval);
888 }
889 
890 #undef PCHAR
891 
892 /*
893  * Called from the panic code to try to get the console working
894  * again in case we paniced inside a kprintf().
895  */
896 void
897 kvcreinitspin(void)
898 {
899 	spin_init(&cons_spin, "kvcre");
900 	atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
901 }
902 
903 /*
904  * Console support thread for constty intercepts.  This is needed because
905  * console tty intercepts can block.  Instead of having kputchar() attempt
906  * to directly write to the console intercept we just force it to log
907  * and wakeup this baby to track and dump the log to constty.
908  */
909 static void
910 constty_daemon(void)
911 {
912 	u_int rindex;
913 	u_int xindex;
914 	u_int n;
915         struct msgbuf *mbp;
916 	struct tty *tp;
917 
918         EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc,
919                               constty_td, SHUTDOWN_PRI_FIRST);
920         constty_td->td_flags |= TDF_SYSTHREAD;
921 
922 	mbp = msgbufp;
923 	rindex = mbp->msg_bufr;		/* persistent loop variable */
924 	xindex = mbp->msg_bufx - 1;	/* anything different than bufx */
925 	cpu_ccfence();
926 
927         for (;;) {
928                 kproc_suspend_loop();
929 
930 		crit_enter();
931 		if (mbp != msgbufp)
932 			mbp = msgbufp;
933 		if (xindex == mbp->msg_bufx ||
934 		    mbp == NULL ||
935 		    msgbufmapped == 0) {
936 			tsleep(constty_td, 0, "waiting", hz*60);
937 			crit_exit();
938 			continue;
939 		}
940 		crit_exit();
941 
942 		/*
943 		 * Get message buf FIFO indices.  rindex is tracking.
944 		 */
945 		xindex = mbp->msg_bufx;
946 		cpu_ccfence();
947 		if ((tp = constty) == NULL) {
948 			rindex = xindex;
949 			continue;
950 		}
951 
952 		/*
953 		 * Check if the calculated bytes has rolled the whole
954 		 * message buffer.
955 		 */
956 		n = xindex - rindex;
957 		if (n > mbp->msg_size - 1024) {
958 			rindex = xindex - mbp->msg_size + 2048;
959 			n = xindex - rindex;
960 		}
961 
962 		/*
963 		 * And dump it.  If constty gets stuck will give up.
964 		 */
965 		while (rindex != xindex) {
966 			u_int ri = rindex % mbp->msg_size;
967 			if (tputchar((uint8_t)mbp->msg_ptr[ri], tp) < 0) {
968 				constty = NULL;
969 				rindex = xindex;
970 				break;
971 			}
972                         if (tp->t_outq.c_cc >= tp->t_ohiwat) {
973 				tsleep(constty_daemon, 0, "blocked", hz / 10);
974 				if (tp->t_outq.c_cc >= tp->t_ohiwat) {
975 					rindex = xindex;
976 					break;
977 				}
978 			}
979 			++rindex;
980 		}
981 	}
982 }
983 
984 static struct kproc_desc constty_kp = {
985         "consttyd",
986 	constty_daemon,
987         &constty_td
988 };
989 SYSINIT(bufdaemon, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY,
990         kproc_start, &constty_kp);
991 
992 /*
993  * Put character in log buffer with a particular priority.
994  *
995  * MPSAFE
996  */
997 static void
998 msglogchar(int c, int pri)
999 {
1000 	static int lastpri = -1;
1001 	static int dangling;
1002 	char nbuf[MAXNBUF];
1003 	char *p;
1004 
1005 	if (!msgbufmapped)
1006 		return;
1007 	if (c == '\0' || c == '\r')
1008 		return;
1009 	if (pri != -1 && pri != lastpri) {
1010 		if (dangling) {
1011 			msgaddchar('\n', NULL);
1012 			dangling = 0;
1013 		}
1014 		msgaddchar('<', NULL);
1015 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
1016 			msgaddchar(*p--, NULL);
1017 		msgaddchar('>', NULL);
1018 		lastpri = pri;
1019 	}
1020 	msgaddchar(c, NULL);
1021 	if (c == '\n') {
1022 		dangling = 0;
1023 		lastpri = -1;
1024 	} else {
1025 		dangling = 1;
1026 	}
1027 }
1028 
1029 /*
1030  * Put char in log buffer.   Make sure nothing blows up beyond repair if
1031  * we have an MP race.
1032  *
1033  * MPSAFE.
1034  */
1035 static void
1036 msgaddchar(int c, void *dummy)
1037 {
1038 	struct msgbuf *mbp;
1039 	u_int lindex;
1040 	u_int rindex;
1041 	u_int xindex;
1042 	u_int n;
1043 
1044 	if (!msgbufmapped)
1045 		return;
1046 	mbp = msgbufp;
1047 	lindex = mbp->msg_bufl;
1048 	rindex = mbp->msg_bufr;
1049 	xindex = mbp->msg_bufx++;	/* Allow SMP race */
1050 	cpu_ccfence();
1051 
1052 	mbp->msg_ptr[xindex % mbp->msg_size] = c;
1053 	n = xindex - lindex;
1054 	if (n > mbp->msg_size - 1024) {
1055 		lindex = xindex - mbp->msg_size + 2048;
1056 		cpu_ccfence();
1057 		mbp->msg_bufl = lindex;
1058 	}
1059 	n = xindex - rindex;
1060 	if (n > mbp->msg_size - 1024) {
1061 		rindex = xindex - mbp->msg_size + 2048;
1062 		cpu_ccfence();
1063 		mbp->msg_bufr = rindex;
1064 	}
1065 }
1066 
1067 static void
1068 msgbufcopy(struct msgbuf *oldp)
1069 {
1070 	u_int rindex;
1071 	u_int xindex;
1072 	u_int n;
1073 
1074 	rindex = oldp->msg_bufr;
1075 	xindex = oldp->msg_bufx;
1076 	cpu_ccfence();
1077 
1078 	n = xindex - rindex;
1079 	if (n > oldp->msg_size - 1024)
1080 		rindex = xindex - oldp->msg_size + 2048;
1081 	while (rindex != xindex) {
1082 		msglogchar(oldp->msg_ptr[rindex % oldp->msg_size], -1);
1083 		++rindex;
1084 	}
1085 }
1086 
1087 void
1088 msgbufinit(void *ptr, size_t size)
1089 {
1090 	char *cp;
1091 	static struct msgbuf *oldp = NULL;
1092 
1093 	size -= sizeof(*msgbufp);
1094 	cp = (char *)ptr;
1095 	msgbufp = (struct msgbuf *) (cp + size);
1096 	if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size) {
1097 		bzero(cp, size);
1098 		bzero(msgbufp, sizeof(*msgbufp));
1099 		msgbufp->msg_magic = MSG_MAGIC;
1100 		msgbufp->msg_size = (char *)msgbufp - cp;
1101 	}
1102 	msgbufp->msg_ptr = cp;
1103 	if (msgbufmapped && oldp != msgbufp)
1104 		msgbufcopy(oldp);
1105 	cpu_mfence();
1106 	msgbufmapped = 1;
1107 	oldp = msgbufp;
1108 }
1109 
1110 /* Sysctls for accessing/clearing the msgbuf */
1111 
1112 static int
1113 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
1114 {
1115         struct msgbuf *mbp;
1116 	struct ucred *cred;
1117 	int error;
1118 	u_int rindex_modulo;
1119 	u_int xindex_modulo;
1120 	u_int rindex;
1121 	u_int xindex;
1122 	u_int n;
1123 
1124 	/*
1125 	 * Only wheel or root can access the message log.
1126 	 */
1127 	if (unprivileged_read_msgbuf == 0) {
1128 		KKASSERT(req->td->td_proc);
1129 		cred = req->td->td_proc->p_ucred;
1130 
1131 		if ((cred->cr_prison || groupmember(0, cred) == 0) &&
1132 		    priv_check(req->td, PRIV_ROOT) != 0
1133 		) {
1134 			return (EPERM);
1135 		}
1136 	}
1137 
1138 	/*
1139 	 * Unwind the buffer, so that it's linear (possibly starting with
1140 	 * some initial nulls).
1141 	 *
1142 	 * We don't push the entire buffer like we did before because
1143 	 * bufr (and bufl) now advance in chunks when the fifo is full,
1144 	 * rather than one character.
1145 	 */
1146 	mbp = msgbufp;
1147 	rindex = mbp->msg_bufr;
1148 	xindex = mbp->msg_bufx;
1149 	n = xindex - rindex;
1150 	if (n > mbp->msg_size - 1024) {
1151 		rindex = xindex - mbp->msg_size + 2048;
1152 		n = xindex - rindex;
1153 	}
1154 	rindex_modulo = rindex % mbp->msg_size;
1155 	xindex_modulo = xindex % mbp->msg_size;
1156 
1157 	if (rindex_modulo < xindex_modulo) {
1158 		/*
1159 		 * Can handle in one linear section.
1160 		 */
1161 		error = sysctl_handle_opaque(oidp,
1162 					     mbp->msg_ptr + rindex_modulo,
1163 					     xindex_modulo - rindex_modulo,
1164 					     req);
1165 	} else if (rindex_modulo == xindex_modulo) {
1166 		/*
1167 		 * Empty buffer, just return a single newline
1168 		 */
1169 		error = sysctl_handle_opaque(oidp, "\n", 1, req);
1170 	} else if (n <= mbp->msg_size - rindex_modulo) {
1171 		/*
1172 		 * Can handle in one linear section.
1173 		 */
1174 		error = sysctl_handle_opaque(oidp,
1175 					     mbp->msg_ptr + rindex_modulo,
1176 					     n - rindex_modulo,
1177 					     req);
1178 	} else {
1179 		/*
1180 		 * Glue together two linear sections into one contiguous
1181 		 * output.
1182 		 */
1183 		error = sysctl_handle_opaque(oidp,
1184 					     mbp->msg_ptr + rindex_modulo,
1185 					     mbp->msg_size - rindex_modulo,
1186 					     req);
1187 		n -= mbp->msg_size - rindex_modulo;
1188 		if (error == 0)
1189 			error = sysctl_handle_opaque(oidp, mbp->msg_ptr,
1190 						     n, req);
1191 	}
1192 	return (error);
1193 }
1194 
1195 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
1196     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
1197 
1198 static int msgbuf_clear;
1199 
1200 static int
1201 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
1202 {
1203 	int error;
1204 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
1205 	if (!error && req->newptr) {
1206 		/* Clear the buffer and reset write pointer */
1207 		msgbufp->msg_bufr = msgbufp->msg_bufx;
1208 		msgbufp->msg_bufl = msgbufp->msg_bufx;
1209 		bzero(msgbufp->msg_ptr, msgbufp->msg_size);
1210 		msgbuf_clear = 0;
1211 	}
1212 	return (error);
1213 }
1214 
1215 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
1216     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0,
1217     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
1218 
1219 #ifdef DDB
1220 
1221 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
1222 {
1223 	u_int rindex;
1224 	u_int i;
1225 	u_int j;
1226 
1227 	if (!msgbufmapped) {
1228 		db_printf("msgbuf not mapped yet\n");
1229 		return;
1230 	}
1231 	db_printf("msgbufp = %p\n", msgbufp);
1232 	db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
1233 		  msgbufp->msg_magic, msgbufp->msg_size,
1234 		  msgbufp->msg_bufr % msgbufp->msg_size,
1235 		  msgbufp->msg_bufx % msgbufp->msg_size,
1236 		  msgbufp->msg_ptr);
1237 
1238 	rindex = msgbufp->msg_bufr;
1239 	for (i = 0; i < msgbufp->msg_size; i++) {
1240 		j = (i + rindex) % msgbufp->msg_size;
1241 		db_printf("%c", msgbufp->msg_ptr[j]);
1242 	}
1243 	db_printf("\n");
1244 }
1245 
1246 #endif /* DDB */
1247 
1248 
1249 void
1250 hexdump(const void *ptr, int length, const char *hdr, int flags)
1251 {
1252 	int i, j, k;
1253 	int cols;
1254 	const unsigned char *cp;
1255 	char delim;
1256 
1257 	if ((flags & HD_DELIM_MASK) != 0)
1258 		delim = (flags & HD_DELIM_MASK) >> 8;
1259 	else
1260 		delim = ' ';
1261 
1262 	if ((flags & HD_COLUMN_MASK) != 0)
1263 		cols = flags & HD_COLUMN_MASK;
1264 	else
1265 		cols = 16;
1266 
1267 	cp = ptr;
1268 	for (i = 0; i < length; i+= cols) {
1269 		if (hdr != NULL)
1270 			kprintf("%s", hdr);
1271 
1272 		if ((flags & HD_OMIT_COUNT) == 0)
1273 			kprintf("%04x  ", i);
1274 
1275 		if ((flags & HD_OMIT_HEX) == 0) {
1276 			for (j = 0; j < cols; j++) {
1277 				k = i + j;
1278 				if (k < length)
1279 					kprintf("%c%02x", delim, cp[k]);
1280 				else
1281 					kprintf("   ");
1282 			}
1283 		}
1284 
1285 		if ((flags & HD_OMIT_CHARS) == 0) {
1286 			kprintf("  |");
1287 			for (j = 0; j < cols; j++) {
1288 				k = i + j;
1289 				if (k >= length)
1290 					kprintf(" ");
1291 				else if (cp[k] >= ' ' && cp[k] <= '~')
1292 					kprintf("%c", cp[k]);
1293 				else
1294 					kprintf(".");
1295 			}
1296 			kprintf("|");
1297 		}
1298 		kprintf("\n");
1299 	}
1300 }
1301 
1302 void
1303 kprint_cpuset(cpumask_t *mask)
1304 {
1305 	int i;
1306 	int b = -1;
1307 	int e = -1;
1308 	int more = 0;
1309 
1310 	kprintf("cpus(");
1311 	CPUSET_FOREACH(i, *mask) {
1312 		if (b < 0) {
1313 			b = i;
1314 			e = b + 1;
1315 			continue;
1316 		}
1317 		if (e == i) {
1318 			++e;
1319 			continue;
1320 		}
1321 		if (more)
1322 			kprintf(", ");
1323 		if (b == e - 1) {
1324 			kprintf("%d", b);
1325 		} else {
1326 			kprintf("%d-%d", b, e - 1);
1327 		}
1328 		more = 1;
1329 		b = i;
1330 		e = b + 1;
1331 	}
1332 	if (more)
1333 		kprintf(", ");
1334 	if (b >= 0) {
1335 		if (b == e - 1) {
1336 			kprintf("%d", b);
1337 		} else {
1338 			kprintf("%d-%d", b, e - 1);
1339 		}
1340 	}
1341 	kprintf(") ");
1342 }
1343