xref: /dflybsd-src/sys/kern/subr_prf.c (revision b370aff7747b2e03ce9b829fbf2877dffdadfb64)
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: src/sys/kern/subr_prf.c,v 1.61.2.5 2002/08/31 18:22:08 dwmalone Exp $
40  * $DragonFly: src/sys/kern/subr_prf.c,v 1.21 2008/07/17 23:56:23 dillon Exp $
41  */
42 
43 #include "opt_ddb.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/kernel.h>
48 #include <sys/msgbuf.h>
49 #include <sys/malloc.h>
50 #include <sys/proc.h>
51 #include <sys/priv.h>
52 #include <sys/tty.h>
53 #include <sys/tprintf.h>
54 #include <sys/stdint.h>
55 #include <sys/syslog.h>
56 #include <sys/cons.h>
57 #include <sys/uio.h>
58 #include <sys/sysctl.h>
59 #include <sys/lock.h>
60 #include <sys/ctype.h>
61 #include <sys/eventhandler.h>
62 #include <sys/kthread.h>
63 
64 #include <sys/thread2.h>
65 #include <sys/spinlock2.h>
66 
67 #ifdef DDB
68 #include <ddb/ddb.h>
69 #endif
70 
71 /*
72  * Note that stdarg.h and the ANSI style va_start macro is used for both
73  * ANSI and traditional C compilers.  We use the __ machine version to stay
74  * within the kernel header file set.
75  */
76 #include <machine/stdarg.h>
77 
78 #define TOCONS		0x01
79 #define TOTTY		0x02
80 #define TOLOG		0x04
81 #define TOWAKEUP	0x08
82 
83 /* Max number conversion buffer length: a u_quad_t in base 2, plus NUL byte. */
84 #define MAXNBUF	(sizeof(intmax_t) * NBBY + 1)
85 
86 struct putchar_arg {
87 	int	flags;
88 	int	pri;
89 	struct	tty *tty;
90 };
91 
92 struct snprintf_arg {
93 	char	*str;
94 	size_t	remain;
95 };
96 
97 extern	int log_open;
98 
99 struct	tty *constty;			/* pointer to console "window" tty */
100 
101 static void  msglogchar(int c, int pri);
102 static void  msgaddchar(int c, void *dummy);
103 static void  kputchar (int ch, void *arg);
104 static char *ksprintn (char *nbuf, uintmax_t num, int base, int *lenp,
105 		       int upper);
106 static void  snprintf_func (int ch, void *arg);
107 
108 static int consintr = 1;		/* Ok to handle console interrupts? */
109 static int msgbufmapped;		/* Set when safe to use msgbuf */
110 static struct spinlock cons_spin = SPINLOCK_INITIALIZER(cons_spin);
111 static thread_t constty_td = NULL;
112 
113 int msgbuftrigger;
114 
115 static int      log_console_output = 1;
116 TUNABLE_INT("kern.log_console_output", &log_console_output);
117 SYSCTL_INT(_kern, OID_AUTO, log_console_output, CTLFLAG_RW,
118     &log_console_output, 0, "");
119 
120 static int unprivileged_read_msgbuf = 1;
121 SYSCTL_INT(_security, OID_AUTO, unprivileged_read_msgbuf, CTLFLAG_RW,
122     &unprivileged_read_msgbuf, 0,
123     "Unprivileged processes may read the kernel message buffer");
124 
125 /*
126  * Warn that a system table is full.
127  */
128 void
129 tablefull(const char *tab)
130 {
131 
132 	log(LOG_ERR, "%s: table is full\n", tab);
133 }
134 
135 /*
136  * Uprintf prints to the controlling terminal for the current process.
137  */
138 int
139 uprintf(const char *fmt, ...)
140 {
141 	struct proc *p = curproc;
142 	__va_list ap;
143 	struct putchar_arg pca;
144 	int retval = 0;
145 
146 	if (p && (p->p_flags & P_CONTROLT) && p->p_session->s_ttyvp) {
147 		__va_start(ap, fmt);
148 		pca.tty = p->p_session->s_ttyp;
149 		pca.flags = TOTTY;
150 
151 		retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
152 		__va_end(ap);
153 	}
154 	return (retval);
155 }
156 
157 tpr_t
158 tprintf_open(struct proc *p)
159 {
160 	if ((p->p_flags & P_CONTROLT) && p->p_session->s_ttyvp) {
161 		sess_hold(p->p_session);
162 		return ((tpr_t) p->p_session);
163 	}
164 	return ((tpr_t) NULL);
165 }
166 
167 void
168 tprintf_close(tpr_t sess)
169 {
170 	if (sess)
171 		sess_rele((struct session *) sess);
172 }
173 
174 /*
175  * tprintf prints on the controlling terminal associated
176  * with the given session.
177  */
178 int
179 tprintf(tpr_t tpr, const char *fmt, ...)
180 {
181 	struct session *sess = (struct session *)tpr;
182 	struct tty *tp = NULL;
183 	int flags = TOLOG;
184 	__va_list ap;
185 	struct putchar_arg pca;
186 	int retval;
187 
188 	if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
189 		flags |= TOTTY;
190 		tp = sess->s_ttyp;
191 	}
192 	__va_start(ap, fmt);
193 	pca.tty = tp;
194 	pca.flags = flags;
195 	pca.pri = LOG_INFO;
196 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
197 	__va_end(ap);
198 	msgbuftrigger = 1;
199 	return (retval);
200 }
201 
202 /*
203  * Ttyprintf displays a message on a tty; it should be used only by
204  * the tty driver, or anything that knows the underlying tty will not
205  * be revoke(2)'d away.  Other callers should use tprintf.
206  */
207 int
208 ttyprintf(struct tty *tp, const char *fmt, ...)
209 {
210 	__va_list ap;
211 	struct putchar_arg pca;
212 	int retval;
213 
214 	__va_start(ap, fmt);
215 	pca.tty = tp;
216 	pca.flags = TOTTY;
217 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
218 	__va_end(ap);
219 	return (retval);
220 }
221 
222 /*
223  * Log writes to the log buffer, and guarantees not to sleep (so can be
224  * called by interrupt routines).  If there is no process reading the
225  * log yet, it writes to the console also.
226  */
227 int
228 log(int level, const char *fmt, ...)
229 {
230 	__va_list ap;
231 	int retval;
232 	struct putchar_arg pca;
233 
234 	pca.tty = NULL;
235 	pca.pri = level;
236 	pca.flags = log_open ? TOLOG : TOCONS;
237 
238 	__va_start(ap, fmt);
239 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
240 	__va_end(ap);
241 
242 	msgbuftrigger = 1;
243 	return (retval);
244 }
245 
246 #define CONSCHUNK 128
247 
248 void
249 log_console(struct uio *uio)
250 {
251 	int c, i, error, iovlen, nl;
252 	struct uio muio;
253 	struct iovec *miov = NULL;
254 	char *consbuffer;
255 	int pri;
256 
257 	if (!log_console_output)
258 		return;
259 
260 	pri = LOG_INFO | LOG_CONSOLE;
261 	muio = *uio;
262 	iovlen = uio->uio_iovcnt * sizeof (struct iovec);
263 	MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
264 	MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
265 	bcopy((caddr_t)muio.uio_iov, (caddr_t)miov, iovlen);
266 	muio.uio_iov = miov;
267 	uio = &muio;
268 
269 	nl = 0;
270 	while (uio->uio_resid > 0) {
271 		c = (int)szmin(uio->uio_resid, CONSCHUNK);
272 		error = uiomove(consbuffer, (size_t)c, uio);
273 		if (error != 0)
274 			break;
275 		for (i = 0; i < c; i++) {
276 			msglogchar(consbuffer[i], pri);
277 			if (consbuffer[i] == '\n')
278 				nl = 1;
279 			else
280 				nl = 0;
281 		}
282 	}
283 	if (!nl)
284 		msglogchar('\n', pri);
285 	msgbuftrigger = 1;
286 	FREE(miov, M_TEMP);
287 	FREE(consbuffer, M_TEMP);
288 	return;
289 }
290 
291 /*
292  * Output to the console.
293  */
294 int
295 kprintf(const char *fmt, ...)
296 {
297 	__va_list ap;
298 	int savintr;
299 	struct putchar_arg pca;
300 	int retval;
301 
302 	savintr = consintr;		/* disable interrupts */
303 	consintr = 0;
304 	__va_start(ap, fmt);
305 	pca.tty = NULL;
306 	pca.flags = TOCONS | TOLOG;
307 	pca.pri = -1;
308 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
309 	__va_end(ap);
310 	if (!panicstr)
311 		msgbuftrigger = 1;
312 	consintr = savintr;		/* reenable interrupts */
313 	return (retval);
314 }
315 
316 int
317 kvprintf(const char *fmt, __va_list ap)
318 {
319 	int savintr;
320 	struct putchar_arg pca;
321 	int retval;
322 
323 	savintr = consintr;		/* disable interrupts */
324 	consintr = 0;
325 	pca.tty = NULL;
326 	pca.flags = TOCONS | TOLOG;
327 	pca.pri = -1;
328 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
329 	if (!panicstr)
330 		msgbuftrigger = 1;
331 	consintr = savintr;		/* reenable interrupts */
332 	return (retval);
333 }
334 
335 /*
336  * Limited rate kprintf.  The passed rate structure must be initialized
337  * with the desired reporting frequency.  A frequency of 0 will result in
338  * no output.
339  *
340  * count may be initialized to a negative number to allow an initial
341  * burst.
342  */
343 void
344 krateprintf(struct krate *rate, const char *fmt, ...)
345 {
346 	__va_list ap;
347 
348 	if (rate->ticks != (int)time_second) {
349 		rate->ticks = (int)time_second;
350 		if (rate->count > 0)
351 			rate->count = 0;
352 	}
353 	if (rate->count < rate->freq) {
354 		++rate->count;
355 		__va_start(ap, fmt);
356 		kvprintf(fmt, ap);
357 		__va_end(ap);
358 	}
359 }
360 
361 /*
362  * Print a character to the dmesg log, the console, and/or the user's
363  * terminal.
364  *
365  * NOTE: TOTTY does not require nonblocking operation, but TOCONS
366  * 	 and TOLOG do.  When we have a constty we still output to
367  *	 the real console but we have a monitoring thread which
368  *	 we wakeup which tracks the log.
369  */
370 static void
371 kputchar(int c, void *arg)
372 {
373 	struct putchar_arg *ap = (struct putchar_arg*) arg;
374 	int flags = ap->flags;
375 	struct tty *tp = ap->tty;
376 
377 	if (panicstr)
378 		constty = NULL;
379 	if ((flags & TOCONS) && tp == NULL && constty)
380 		flags |= TOLOG | TOWAKEUP;
381 	if ((flags & TOTTY) && tputchar(c, tp) < 0)
382 		ap->flags &= ~TOTTY;
383 	if ((flags & TOLOG))
384 		msglogchar(c, ap->pri);
385 	if ((flags & TOCONS) && c)
386 		cnputc(c);
387 	if (flags & TOWAKEUP)
388 		wakeup(constty_td);
389 }
390 
391 /*
392  * Scaled down version of sprintf(3).
393  */
394 int
395 ksprintf(char *buf, const char *cfmt, ...)
396 {
397 	int retval;
398 	__va_list ap;
399 
400 	__va_start(ap, cfmt);
401 	retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
402 	buf[retval] = '\0';
403 	__va_end(ap);
404 	return (retval);
405 }
406 
407 /*
408  * Scaled down version of vsprintf(3).
409  */
410 int
411 kvsprintf(char *buf, const char *cfmt, __va_list ap)
412 {
413 	int retval;
414 
415 	retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
416 	buf[retval] = '\0';
417 	return (retval);
418 }
419 
420 /*
421  * Scaled down version of snprintf(3).
422  */
423 int
424 ksnprintf(char *str, size_t size, const char *format, ...)
425 {
426 	int retval;
427 	__va_list ap;
428 
429 	__va_start(ap, format);
430 	retval = kvsnprintf(str, size, format, ap);
431 	__va_end(ap);
432 	return(retval);
433 }
434 
435 /*
436  * Scaled down version of vsnprintf(3).
437  */
438 int
439 kvsnprintf(char *str, size_t size, const char *format, __va_list ap)
440 {
441 	struct snprintf_arg info;
442 	int retval;
443 
444 	info.str = str;
445 	info.remain = size;
446 	retval = kvcprintf(format, snprintf_func, &info, 10, ap);
447 	if (info.remain >= 1)
448 		*info.str++ = '\0';
449 	return (retval);
450 }
451 
452 int
453 ksnrprintf(char *str, size_t size, int radix, const char *format, ...)
454 {
455 	int retval;
456 	__va_list ap;
457 
458 	__va_start(ap, format);
459 	retval = kvsnrprintf(str, size, radix, format, ap);
460 	__va_end(ap);
461 	return(retval);
462 }
463 
464 int
465 kvsnrprintf(char *str, size_t size, int radix, const char *format, __va_list ap)
466 {
467 	struct snprintf_arg info;
468 	int retval;
469 
470 	info.str = str;
471 	info.remain = size;
472 	retval = kvcprintf(format, snprintf_func, &info, radix, ap);
473 	if (info.remain >= 1)
474 		*info.str++ = '\0';
475 	return (retval);
476 }
477 
478 int
479 kvasnrprintf(char **strp, size_t size, int radix,
480 	     const char *format, __va_list ap)
481 {
482 	struct snprintf_arg info;
483 	int retval;
484 
485 	*strp = kmalloc(size, M_TEMP, M_WAITOK);
486 	info.str = *strp;
487 	info.remain = size;
488 	retval = kvcprintf(format, snprintf_func, &info, radix, ap);
489 	if (info.remain >= 1)
490 		*info.str++ = '\0';
491 	return (retval);
492 }
493 
494 void
495 kvasfree(char **strp)
496 {
497 	if (*strp) {
498 		kfree(*strp, M_TEMP);
499 		*strp = NULL;
500 	}
501 }
502 
503 static void
504 snprintf_func(int ch, void *arg)
505 {
506 	struct snprintf_arg *const info = arg;
507 
508 	if (info->remain >= 2) {
509 		*info->str++ = ch;
510 		info->remain--;
511 	}
512 }
513 
514 /*
515  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
516  * order; return an optional length and a pointer to the last character
517  * written in the buffer (i.e., the first character of the string).
518  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
519  */
520 static char *
521 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
522 {
523 	char *p, c;
524 
525 	p = nbuf;
526 	*p = '\0';
527 	do {
528 		c = hex2ascii(num % base);
529 		*++p = upper ? toupper(c) : c;
530 	} while (num /= base);
531 	if (lenp)
532 		*lenp = p - nbuf;
533 	return (p);
534 }
535 
536 /*
537  * Scaled down version of printf(3).
538  *
539  * Two additional formats:
540  *
541  * The format %b is supported to decode error registers.
542  * Its usage is:
543  *
544  *	kprintf("reg=%b\n", regval, "<base><arg>*");
545  *
546  * where <base> is the output base expressed as a control character, e.g.
547  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
548  * the first of which gives the bit number to be inspected (origin 1), and
549  * the next characters (up to a control character, i.e. a character <= 32),
550  * give the name of the register.  Thus:
551  *
552  *	kvcprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
553  *
554  * would produce output:
555  *
556  *	reg=3<BITTWO,BITONE>
557  *
558  * XXX:  %D  -- Hexdump, takes pointer and separator string:
559  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
560  *		("%*D", len, ptr, " " -> XX XX XX XX ...
561  */
562 
563 #define PCHAR(c) {int cc=(c); if(func) (*func)(cc,arg); else *d++=cc; retval++;}
564 
565 int
566 kvcprintf(char const *fmt, void (*func)(int, void*), void *arg,
567 	  int radix, __va_list ap)
568 {
569 	char nbuf[MAXNBUF];
570 	char *d;
571 	const char *p, *percent, *q;
572 	u_char *up;
573 	int ch, n;
574 	uintmax_t num;
575 	int base, tmp, width, ladjust, sharpflag, neg, sign, dot;
576 	int cflag, hflag, jflag, lflag, qflag, tflag, zflag;
577 	int dwidth, upper;
578 	char padc;
579 	int retval = 0, stop = 0;
580 	int usespin;
581 
582 	/*
583 	 * Make a supreme effort to avoid reentrant panics or deadlocks.
584 	 *
585 	 * NOTE!  Do nothing that would access mycpu/gd/fs unless the
586 	 *	  function is the normal kputchar(), which allows us to
587 	 *	  use this function for very early debugging with a special
588 	 *	  function.
589 	 */
590 	if (func == kputchar) {
591 		if (mycpu->gd_flags & GDF_KPRINTF)
592 			return(0);
593 		atomic_set_long(&mycpu->gd_flags, GDF_KPRINTF);
594 	}
595 
596 	num = 0;
597 	if (!func)
598 		d = (char *) arg;
599 	else
600 		d = NULL;
601 
602 	if (fmt == NULL)
603 		fmt = "(fmt null)\n";
604 
605 	if (radix < 2 || radix > 36)
606 		radix = 10;
607 
608 	usespin = (func == kputchar &&
609 		   panic_cpu_gd != mycpu &&
610 		   (((struct putchar_arg *)arg)->flags & TOTTY) == 0);
611 	if (usespin) {
612 		crit_enter_hard();
613 		spin_lock(&cons_spin);
614 	}
615 
616 	for (;;) {
617 		padc = ' ';
618 		width = 0;
619 		while ((ch = (u_char)*fmt++) != '%' || stop) {
620 			if (ch == '\0')
621 				goto done;
622 			PCHAR(ch);
623 		}
624 		percent = fmt - 1;
625 		dot = dwidth = ladjust = neg = sharpflag = sign = upper = 0;
626 		cflag = hflag = jflag = lflag = qflag = tflag = zflag = 0;
627 
628 reswitch:
629 		switch (ch = (u_char)*fmt++) {
630 		case '.':
631 			dot = 1;
632 			goto reswitch;
633 		case '#':
634 			sharpflag = 1;
635 			goto reswitch;
636 		case '+':
637 			sign = 1;
638 			goto reswitch;
639 		case '-':
640 			ladjust = 1;
641 			goto reswitch;
642 		case '%':
643 			PCHAR(ch);
644 			break;
645 		case '*':
646 			if (!dot) {
647 				width = __va_arg(ap, int);
648 				if (width < 0) {
649 					ladjust = !ladjust;
650 					width = -width;
651 				}
652 			} else {
653 				dwidth = __va_arg(ap, int);
654 			}
655 			goto reswitch;
656 		case '0':
657 			if (!dot) {
658 				padc = '0';
659 				goto reswitch;
660 			}
661 		case '1': case '2': case '3': case '4':
662 		case '5': case '6': case '7': case '8': case '9':
663 				for (n = 0;; ++fmt) {
664 					n = n * 10 + ch - '0';
665 					ch = *fmt;
666 					if (ch < '0' || ch > '9')
667 						break;
668 				}
669 			if (dot)
670 				dwidth = n;
671 			else
672 				width = n;
673 			goto reswitch;
674 		case 'b':
675 			num = (u_int)__va_arg(ap, int);
676 			p = __va_arg(ap, char *);
677 			for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
678 				PCHAR(*q--);
679 
680 			if (num == 0)
681 				break;
682 
683 			for (tmp = 0; *p;) {
684 				n = *p++;
685 				if (num & (1 << (n - 1))) {
686 					PCHAR(tmp ? ',' : '<');
687 					for (; (n = *p) > ' '; ++p)
688 						PCHAR(n);
689 					tmp = 1;
690 				} else
691 					for (; *p > ' '; ++p)
692 						continue;
693 			}
694 			if (tmp)
695 				PCHAR('>');
696 			break;
697 		case 'c':
698 			PCHAR(__va_arg(ap, int));
699 			break;
700 		case 'D':
701 			up = __va_arg(ap, u_char *);
702 			p = __va_arg(ap, char *);
703 			if (!width)
704 				width = 16;
705 			while(width--) {
706 				PCHAR(hex2ascii(*up >> 4));
707 				PCHAR(hex2ascii(*up & 0x0f));
708 				up++;
709 				if (width)
710 					for (q=p;*q;q++)
711 						PCHAR(*q);
712 			}
713 			break;
714 		case 'd':
715 		case 'i':
716 			base = 10;
717 			sign = 1;
718 			goto handle_sign;
719 		case 'h':
720 			if (hflag) {
721 				hflag = 0;
722 				cflag = 1;
723 			} else
724 				hflag = 1;
725 			goto reswitch;
726 		case 'j':
727 			jflag = 1;
728 			goto reswitch;
729 		case 'l':
730 			if (lflag) {
731 				lflag = 0;
732 				qflag = 1;
733 			} else
734 				lflag = 1;
735 			goto reswitch;
736 		case 'n':
737 			if (cflag)
738 				*(__va_arg(ap, char *)) = retval;
739 			else if (hflag)
740 				*(__va_arg(ap, short *)) = retval;
741 			else if (jflag)
742 				*(__va_arg(ap, intmax_t *)) = retval;
743 			else if (lflag)
744 				*(__va_arg(ap, long *)) = retval;
745 			else if (qflag)
746 				*(__va_arg(ap, quad_t *)) = retval;
747 			else
748 				*(__va_arg(ap, int *)) = retval;
749 			break;
750 		case 'o':
751 			base = 8;
752 			goto handle_nosign;
753 		case 'p':
754 			base = 16;
755 			sharpflag = (width == 0);
756 			sign = 0;
757 			num = (uintptr_t)__va_arg(ap, void *);
758 			goto number;
759 		case 'q':
760 			qflag = 1;
761 			goto reswitch;
762 		case 'r':
763 			base = radix;
764 			if (sign)
765 				goto handle_sign;
766 			goto handle_nosign;
767 		case 's':
768 			p = __va_arg(ap, char *);
769 			if (p == NULL)
770 				p = "(null)";
771 			if (!dot)
772 				n = strlen (p);
773 			else
774 				for (n = 0; n < dwidth && p[n]; n++)
775 					continue;
776 
777 			width -= n;
778 
779 			if (!ladjust && width > 0)
780 				while (width--)
781 					PCHAR(padc);
782 			while (n--)
783 				PCHAR(*p++);
784 			if (ladjust && width > 0)
785 				while (width--)
786 					PCHAR(padc);
787 			break;
788 		case 't':
789 			tflag = 1;
790 			goto reswitch;
791 		case 'u':
792 			base = 10;
793 			goto handle_nosign;
794 		case 'X':
795 			upper = 1;
796 			/* FALLTHROUGH */
797 		case 'x':
798 			base = 16;
799 			goto handle_nosign;
800 		case 'z':
801 			zflag = 1;
802 			goto reswitch;
803 handle_nosign:
804 			sign = 0;
805 			if (cflag)
806 				num = (u_char)__va_arg(ap, int);
807 			else if (hflag)
808 				num = (u_short)__va_arg(ap, int);
809 			else if (jflag)
810 				num = __va_arg(ap, uintmax_t);
811 			else if (lflag)
812 				num = __va_arg(ap, u_long);
813 			else if (qflag)
814 				num = __va_arg(ap, u_quad_t);
815 			else if (tflag)
816 				num = __va_arg(ap, ptrdiff_t);
817 			else if (zflag)
818 				num = __va_arg(ap, size_t);
819 			else
820 				num = __va_arg(ap, u_int);
821 			goto number;
822 handle_sign:
823 			if (cflag)
824 				num = (char)__va_arg(ap, int);
825 			else if (hflag)
826 				num = (short)__va_arg(ap, int);
827 			else if (jflag)
828 				num = __va_arg(ap, intmax_t);
829 			else if (lflag)
830 				num = __va_arg(ap, long);
831 			else if (qflag)
832 				num = __va_arg(ap, quad_t);
833 			else if (tflag)
834 				num = __va_arg(ap, ptrdiff_t);
835 			else if (zflag)
836 				num = __va_arg(ap, ssize_t);
837 			else
838 				num = __va_arg(ap, int);
839 number:
840 			if (sign && (intmax_t)num < 0) {
841 				neg = 1;
842 				num = -(intmax_t)num;
843 			}
844 			p = ksprintn(nbuf, num, base, &tmp, upper);
845 			if (sharpflag && num != 0) {
846 				if (base == 8)
847 					tmp++;
848 				else if (base == 16)
849 					tmp += 2;
850 			}
851 			if (neg)
852 				tmp++;
853 
854 			if (!ladjust && padc != '0' && width &&
855 			    (width -= tmp) > 0) {
856 				while (width--)
857 					PCHAR(padc);
858 			}
859 			if (neg)
860 				PCHAR('-');
861 			if (sharpflag && num != 0) {
862 				if (base == 8) {
863 					PCHAR('0');
864 				} else if (base == 16) {
865 					PCHAR('0');
866 					PCHAR('x');
867 				}
868 			}
869 			if (!ladjust && width && (width -= tmp) > 0)
870 				while (width--)
871 					PCHAR(padc);
872 
873 			while (*p)
874 				PCHAR(*p--);
875 
876 			if (ladjust && width && (width -= tmp) > 0)
877 				while (width--)
878 					PCHAR(padc);
879 
880 			break;
881 		default:
882 			while (percent < fmt)
883 				PCHAR(*percent++);
884 			/*
885 			 * Since we ignore an formatting argument it is no
886 			 * longer safe to obey the remaining formatting
887 			 * arguments as the arguments will no longer match
888 			 * the format specs.
889 			 */
890 			stop = 1;
891 			break;
892 		}
893 	}
894 done:
895 	/*
896 	 * Cleanup reentrancy issues.
897 	 */
898 	if (func == kputchar)
899 		atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
900 	if (usespin) {
901 		spin_unlock(&cons_spin);
902 		crit_exit_hard();
903 	}
904 	return (retval);
905 }
906 
907 #undef PCHAR
908 
909 /*
910  * Called from the panic code to try to get the console working
911  * again in case we paniced inside a kprintf().
912  */
913 void
914 kvcreinitspin(void)
915 {
916 	spin_init(&cons_spin);
917 	atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
918 }
919 
920 /*
921  * Console support thread for constty intercepts.  This is needed because
922  * console tty intercepts can block.  Instead of having kputchar() attempt
923  * to directly write to the console intercept we just force it to log
924  * and wakeup this baby to track and dump the log to constty.
925  */
926 static void
927 constty_daemon(void)
928 {
929 	int rindex = -1;
930 	int windex = -1;
931         struct msgbuf *mbp;
932 	struct tty *tp;
933 
934         EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc,
935                               constty_td, SHUTDOWN_PRI_FIRST);
936         constty_td->td_flags |= TDF_SYSTHREAD;
937 
938         for (;;) {
939                 kproc_suspend_loop();
940 
941 		crit_enter();
942 		mbp = msgbufp;
943 		if (mbp == NULL || msgbufmapped == 0 ||
944 		    windex == mbp->msg_bufx) {
945 			tsleep(constty_td, 0, "waiting", hz*60);
946 			crit_exit();
947 			continue;
948 		}
949 		windex = mbp->msg_bufx;
950 		crit_exit();
951 
952 		/*
953 		 * Get message buf FIFO indices.  rindex is tracking.
954 		 */
955 		if ((tp = constty) == NULL) {
956 			rindex = mbp->msg_bufx;
957 			continue;
958 		}
959 
960 		/*
961 		 * Don't blow up if the message buffer is broken
962 		 */
963 		if (windex < 0 || windex >= mbp->msg_size)
964 			continue;
965 		if (rindex < 0 || rindex >= mbp->msg_size)
966 			rindex = windex;
967 
968 		/*
969 		 * And dump it.  If constty gets stuck will give up.
970 		 */
971 		while (rindex != windex) {
972 			if (tputchar((uint8_t)mbp->msg_ptr[rindex], tp) < 0) {
973 				constty = NULL;
974 				rindex = mbp->msg_bufx;
975 				break;
976 			}
977 			if (++rindex >= mbp->msg_size)
978 				rindex = 0;
979                         if (tp->t_outq.c_cc >= tp->t_ohiwat) {
980 				tsleep(constty_daemon, 0, "blocked", hz / 10);
981 				if (tp->t_outq.c_cc >= tp->t_ohiwat) {
982 					rindex = windex;
983 					break;
984 				}
985 			}
986 		}
987 	}
988 }
989 
990 static struct kproc_desc constty_kp = {
991         "consttyd",
992 	constty_daemon,
993         &constty_td
994 };
995 SYSINIT(bufdaemon, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY,
996         kproc_start, &constty_kp)
997 
998 /*
999  * Put character in log buffer with a particular priority.
1000  *
1001  * MPSAFE
1002  */
1003 static void
1004 msglogchar(int c, int pri)
1005 {
1006 	static int lastpri = -1;
1007 	static int dangling;
1008 	char nbuf[MAXNBUF];
1009 	char *p;
1010 
1011 	if (!msgbufmapped)
1012 		return;
1013 	if (c == '\0' || c == '\r')
1014 		return;
1015 	if (pri != -1 && pri != lastpri) {
1016 		if (dangling) {
1017 			msgaddchar('\n', NULL);
1018 			dangling = 0;
1019 		}
1020 		msgaddchar('<', NULL);
1021 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
1022 			msgaddchar(*p--, NULL);
1023 		msgaddchar('>', NULL);
1024 		lastpri = pri;
1025 	}
1026 	msgaddchar(c, NULL);
1027 	if (c == '\n') {
1028 		dangling = 0;
1029 		lastpri = -1;
1030 	} else {
1031 		dangling = 1;
1032 	}
1033 }
1034 
1035 /*
1036  * Put char in log buffer.   Make sure nothing blows up beyond repair if
1037  * we have an MP race.
1038  *
1039  * MPSAFE.
1040  */
1041 static void
1042 msgaddchar(int c, void *dummy)
1043 {
1044 	struct msgbuf *mbp;
1045 	int rindex;
1046 	int windex;
1047 
1048 	if (!msgbufmapped)
1049 		return;
1050 	mbp = msgbufp;
1051 	windex = mbp->msg_bufx;
1052 	mbp->msg_ptr[windex] = c;
1053 	if (++windex >= mbp->msg_size)
1054 		windex = 0;
1055 	rindex = mbp->msg_bufr;
1056 	if (windex == rindex) {
1057 		rindex += 32;
1058 		if (rindex >= mbp->msg_size)
1059 			rindex -= mbp->msg_size;
1060 		mbp->msg_bufr = rindex;
1061 	}
1062 	mbp->msg_bufx = windex;
1063 }
1064 
1065 static void
1066 msgbufcopy(struct msgbuf *oldp)
1067 {
1068 	int pos;
1069 
1070 	pos = oldp->msg_bufr;
1071 	while (pos != oldp->msg_bufx) {
1072 		msglogchar(oldp->msg_ptr[pos], -1);
1073 		if (++pos >= oldp->msg_size)
1074 			pos = 0;
1075 	}
1076 }
1077 
1078 void
1079 msgbufinit(void *ptr, size_t size)
1080 {
1081 	char *cp;
1082 	static struct msgbuf *oldp = NULL;
1083 
1084 	size -= sizeof(*msgbufp);
1085 	cp = (char *)ptr;
1086 	msgbufp = (struct msgbuf *) (cp + size);
1087 	if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size ||
1088 	    msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) {
1089 		bzero(cp, size);
1090 		bzero(msgbufp, sizeof(*msgbufp));
1091 		msgbufp->msg_magic = MSG_MAGIC;
1092 		msgbufp->msg_size = (char *)msgbufp - cp;
1093 	}
1094 	msgbufp->msg_ptr = cp;
1095 	if (msgbufmapped && oldp != msgbufp)
1096 		msgbufcopy(oldp);
1097 	msgbufmapped = 1;
1098 	oldp = msgbufp;
1099 }
1100 
1101 /* Sysctls for accessing/clearing the msgbuf */
1102 
1103 static int
1104 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
1105 {
1106 	struct ucred *cred;
1107 	int error;
1108 
1109 	/*
1110 	 * Only wheel or root can access the message log.
1111 	 */
1112 	if (unprivileged_read_msgbuf == 0) {
1113 		KKASSERT(req->td->td_proc);
1114 		cred = req->td->td_proc->p_ucred;
1115 
1116 		if ((cred->cr_prison || groupmember(0, cred) == 0) &&
1117 		    priv_check(req->td, PRIV_ROOT) != 0
1118 		) {
1119 			return (EPERM);
1120 		}
1121 	}
1122 
1123 	/*
1124 	 * Unwind the buffer, so that it's linear (possibly starting with
1125 	 * some initial nulls).
1126 	 */
1127 	error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr + msgbufp->msg_bufx,
1128 	    msgbufp->msg_size - msgbufp->msg_bufx, req);
1129 	if (error)
1130 		return (error);
1131 	if (msgbufp->msg_bufx > 0) {
1132 		error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr,
1133 		    msgbufp->msg_bufx, req);
1134 	}
1135 	return (error);
1136 }
1137 
1138 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
1139     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
1140 
1141 static int msgbuf_clear;
1142 
1143 static int
1144 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
1145 {
1146 	int error;
1147 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
1148 	if (!error && req->newptr) {
1149 		/* Clear the buffer and reset write pointer */
1150 		bzero(msgbufp->msg_ptr, msgbufp->msg_size);
1151 		msgbufp->msg_bufr = msgbufp->msg_bufx = 0;
1152 		msgbuf_clear = 0;
1153 	}
1154 	return (error);
1155 }
1156 
1157 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
1158     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0,
1159     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
1160 
1161 #ifdef DDB
1162 
1163 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
1164 {
1165 	int i, j;
1166 
1167 	if (!msgbufmapped) {
1168 		db_printf("msgbuf not mapped yet\n");
1169 		return;
1170 	}
1171 	db_printf("msgbufp = %p\n", msgbufp);
1172 	db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
1173 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr,
1174 	    msgbufp->msg_bufx, msgbufp->msg_ptr);
1175 	for (i = 0; i < msgbufp->msg_size; i++) {
1176 		j = (i + msgbufp->msg_bufr) % msgbufp->msg_size;
1177 		db_printf("%c", msgbufp->msg_ptr[j]);
1178 	}
1179 	db_printf("\n");
1180 }
1181 
1182 #endif /* DDB */
1183 
1184 
1185 void
1186 hexdump(const void *ptr, int length, const char *hdr, int flags)
1187 {
1188 	int i, j, k;
1189 	int cols;
1190 	const unsigned char *cp;
1191 	char delim;
1192 
1193 	if ((flags & HD_DELIM_MASK) != 0)
1194 		delim = (flags & HD_DELIM_MASK) >> 8;
1195 	else
1196 		delim = ' ';
1197 
1198 	if ((flags & HD_COLUMN_MASK) != 0)
1199 		cols = flags & HD_COLUMN_MASK;
1200 	else
1201 		cols = 16;
1202 
1203 	cp = ptr;
1204 	for (i = 0; i < length; i+= cols) {
1205 		if (hdr != NULL)
1206 			kprintf("%s", hdr);
1207 
1208 		if ((flags & HD_OMIT_COUNT) == 0)
1209 			kprintf("%04x  ", i);
1210 
1211 		if ((flags & HD_OMIT_HEX) == 0) {
1212 			for (j = 0; j < cols; j++) {
1213 				k = i + j;
1214 				if (k < length)
1215 					kprintf("%c%02x", delim, cp[k]);
1216 				else
1217 					kprintf("   ");
1218 			}
1219 		}
1220 
1221 		if ((flags & HD_OMIT_CHARS) == 0) {
1222 			kprintf("  |");
1223 			for (j = 0; j < cols; j++) {
1224 				k = i + j;
1225 				if (k >= length)
1226 					kprintf(" ");
1227 				else if (cp[k] >= ' ' && cp[k] <= '~')
1228 					kprintf("%c", cp[k]);
1229 				else
1230 					kprintf(".");
1231 			}
1232 			kprintf("|");
1233 		}
1234 		kprintf("\n");
1235 	}
1236 }
1237