xref: /dragonfly/sys/kern/subr_prf.c (revision ad9f8794)
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_flag & P_CONTROLT &&
147 	    p->p_session->s_ttyvp) {
148 		__va_start(ap, fmt);
149 		pca.tty = p->p_session->s_ttyp;
150 		pca.flags = TOTTY;
151 
152 		retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
153 		__va_end(ap);
154 	}
155 	return (retval);
156 }
157 
158 tpr_t
159 tprintf_open(struct proc *p)
160 {
161 	if ((p->p_flag & P_CONTROLT) && p->p_session->s_ttyvp) {
162 		sess_hold(p->p_session);
163 		return ((tpr_t) p->p_session);
164 	}
165 	return ((tpr_t) NULL);
166 }
167 
168 void
169 tprintf_close(tpr_t sess)
170 {
171 	if (sess)
172 		sess_rele((struct session *) sess);
173 }
174 
175 /*
176  * tprintf prints on the controlling terminal associated
177  * with the given session.
178  */
179 int
180 tprintf(tpr_t tpr, const char *fmt, ...)
181 {
182 	struct session *sess = (struct session *)tpr;
183 	struct tty *tp = NULL;
184 	int flags = TOLOG;
185 	__va_list ap;
186 	struct putchar_arg pca;
187 	int retval;
188 
189 	if (sess && sess->s_ttyvp && ttycheckoutq(sess->s_ttyp, 0)) {
190 		flags |= TOTTY;
191 		tp = sess->s_ttyp;
192 	}
193 	__va_start(ap, fmt);
194 	pca.tty = tp;
195 	pca.flags = flags;
196 	pca.pri = LOG_INFO;
197 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
198 	__va_end(ap);
199 	msgbuftrigger = 1;
200 	return (retval);
201 }
202 
203 /*
204  * Ttyprintf displays a message on a tty; it should be used only by
205  * the tty driver, or anything that knows the underlying tty will not
206  * be revoke(2)'d away.  Other callers should use tprintf.
207  */
208 int
209 ttyprintf(struct tty *tp, const char *fmt, ...)
210 {
211 	__va_list ap;
212 	struct putchar_arg pca;
213 	int retval;
214 
215 	__va_start(ap, fmt);
216 	pca.tty = tp;
217 	pca.flags = TOTTY;
218 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
219 	__va_end(ap);
220 	return (retval);
221 }
222 
223 /*
224  * Log writes to the log buffer, and guarantees not to sleep (so can be
225  * called by interrupt routines).  If there is no process reading the
226  * log yet, it writes to the console also.
227  */
228 int
229 log(int level, const char *fmt, ...)
230 {
231 	__va_list ap;
232 	int retval;
233 	struct putchar_arg pca;
234 
235 	pca.tty = NULL;
236 	pca.pri = level;
237 	pca.flags = log_open ? TOLOG : TOCONS;
238 
239 	__va_start(ap, fmt);
240 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
241 	__va_end(ap);
242 
243 	msgbuftrigger = 1;
244 	return (retval);
245 }
246 
247 #define CONSCHUNK 128
248 
249 void
250 log_console(struct uio *uio)
251 {
252 	int c, i, error, iovlen, nl;
253 	struct uio muio;
254 	struct iovec *miov = NULL;
255 	char *consbuffer;
256 	int pri;
257 
258 	if (!log_console_output)
259 		return;
260 
261 	pri = LOG_INFO | LOG_CONSOLE;
262 	muio = *uio;
263 	iovlen = uio->uio_iovcnt * sizeof (struct iovec);
264 	MALLOC(miov, struct iovec *, iovlen, M_TEMP, M_WAITOK);
265 	MALLOC(consbuffer, char *, CONSCHUNK, M_TEMP, M_WAITOK);
266 	bcopy((caddr_t)muio.uio_iov, (caddr_t)miov, iovlen);
267 	muio.uio_iov = miov;
268 	uio = &muio;
269 
270 	nl = 0;
271 	while (uio->uio_resid > 0) {
272 		c = (int)szmin(uio->uio_resid, CONSCHUNK);
273 		error = uiomove(consbuffer, (size_t)c, uio);
274 		if (error != 0)
275 			break;
276 		for (i = 0; i < c; i++) {
277 			msglogchar(consbuffer[i], pri);
278 			if (consbuffer[i] == '\n')
279 				nl = 1;
280 			else
281 				nl = 0;
282 		}
283 	}
284 	if (!nl)
285 		msglogchar('\n', pri);
286 	msgbuftrigger = 1;
287 	FREE(miov, M_TEMP);
288 	FREE(consbuffer, M_TEMP);
289 	return;
290 }
291 
292 /*
293  * Output to the console.
294  */
295 int
296 kprintf(const char *fmt, ...)
297 {
298 	__va_list ap;
299 	int savintr;
300 	struct putchar_arg pca;
301 	int retval;
302 
303 	savintr = consintr;		/* disable interrupts */
304 	consintr = 0;
305 	__va_start(ap, fmt);
306 	pca.tty = NULL;
307 	pca.flags = TOCONS | TOLOG;
308 	pca.pri = -1;
309 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
310 	__va_end(ap);
311 	if (!panicstr)
312 		msgbuftrigger = 1;
313 	consintr = savintr;		/* reenable interrupts */
314 	return (retval);
315 }
316 
317 int
318 kvprintf(const char *fmt, __va_list ap)
319 {
320 	int savintr;
321 	struct putchar_arg pca;
322 	int retval;
323 
324 	savintr = consintr;		/* disable interrupts */
325 	consintr = 0;
326 	pca.tty = NULL;
327 	pca.flags = TOCONS | TOLOG;
328 	pca.pri = -1;
329 	retval = kvcprintf(fmt, kputchar, &pca, 10, ap);
330 	if (!panicstr)
331 		msgbuftrigger = 1;
332 	consintr = savintr;		/* reenable interrupts */
333 	return (retval);
334 }
335 
336 /*
337  * Limited rate kprintf.  The passed rate structure must be initialized
338  * with the desired reporting frequency.  A frequency of 0 will result in
339  * no output.
340  *
341  * count may be initialized to a negative number to allow an initial
342  * burst.
343  */
344 void
345 krateprintf(struct krate *rate, const char *fmt, ...)
346 {
347 	__va_list ap;
348 
349 	if (rate->ticks != (int)time_second) {
350 		rate->ticks = (int)time_second;
351 		if (rate->count > 0)
352 			rate->count = 0;
353 	}
354 	if (rate->count < rate->freq) {
355 		++rate->count;
356 		__va_start(ap, fmt);
357 		kvprintf(fmt, ap);
358 		__va_end(ap);
359 	}
360 }
361 
362 /*
363  * Print a character to the dmesg log, the console, and/or the user's
364  * terminal.
365  *
366  * NOTE: TOTTY does not require nonblocking operation, but TOCONS
367  * 	 and TOLOG do.  When we have a constty we still output to
368  *	 the real console but we have a monitoring thread which
369  *	 we wakeup which tracks the log.
370  */
371 static void
372 kputchar(int c, void *arg)
373 {
374 	struct putchar_arg *ap = (struct putchar_arg*) arg;
375 	int flags = ap->flags;
376 	struct tty *tp = ap->tty;
377 
378 	if (panicstr)
379 		constty = NULL;
380 	if ((flags & TOCONS) && tp == NULL && constty)
381 		flags |= TOLOG | TOWAKEUP;
382 	if ((flags & TOTTY) && tputchar(c, tp) < 0)
383 		ap->flags &= ~TOTTY;
384 	if ((flags & TOLOG))
385 		msglogchar(c, ap->pri);
386 	if ((flags & TOCONS) && c)
387 		cnputc(c);
388 	if (flags & TOWAKEUP)
389 		wakeup(constty_td);
390 }
391 
392 /*
393  * Scaled down version of sprintf(3).
394  */
395 int
396 ksprintf(char *buf, const char *cfmt, ...)
397 {
398 	int retval;
399 	__va_list ap;
400 
401 	__va_start(ap, cfmt);
402 	retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
403 	buf[retval] = '\0';
404 	__va_end(ap);
405 	return (retval);
406 }
407 
408 /*
409  * Scaled down version of vsprintf(3).
410  */
411 int
412 kvsprintf(char *buf, const char *cfmt, __va_list ap)
413 {
414 	int retval;
415 
416 	retval = kvcprintf(cfmt, NULL, (void *)buf, 10, ap);
417 	buf[retval] = '\0';
418 	return (retval);
419 }
420 
421 /*
422  * Scaled down version of snprintf(3).
423  */
424 int
425 ksnprintf(char *str, size_t size, const char *format, ...)
426 {
427 	int retval;
428 	__va_list ap;
429 
430 	__va_start(ap, format);
431 	retval = kvsnprintf(str, size, format, ap);
432 	__va_end(ap);
433 	return(retval);
434 }
435 
436 /*
437  * Scaled down version of vsnprintf(3).
438  */
439 int
440 kvsnprintf(char *str, size_t size, const char *format, __va_list ap)
441 {
442 	struct snprintf_arg info;
443 	int retval;
444 
445 	info.str = str;
446 	info.remain = size;
447 	retval = kvcprintf(format, snprintf_func, &info, 10, ap);
448 	if (info.remain >= 1)
449 		*info.str++ = '\0';
450 	return (retval);
451 }
452 
453 int
454 ksnrprintf(char *str, size_t size, int radix, const char *format, ...)
455 {
456 	int retval;
457 	__va_list ap;
458 
459 	__va_start(ap, format);
460 	retval = kvsnrprintf(str, size, radix, format, ap);
461 	__va_end(ap);
462 	return(retval);
463 }
464 
465 int
466 kvsnrprintf(char *str, size_t size, int radix, const char *format, __va_list ap)
467 {
468 	struct snprintf_arg info;
469 	int retval;
470 
471 	info.str = str;
472 	info.remain = size;
473 	retval = kvcprintf(format, snprintf_func, &info, radix, ap);
474 	if (info.remain >= 1)
475 		*info.str++ = '\0';
476 	return (retval);
477 }
478 
479 int
480 kvasnrprintf(char **strp, size_t size, int radix,
481 	     const char *format, __va_list ap)
482 {
483 	struct snprintf_arg info;
484 	int retval;
485 
486 	*strp = kmalloc(size, M_TEMP, M_WAITOK);
487 	info.str = *strp;
488 	info.remain = size;
489 	retval = kvcprintf(format, snprintf_func, &info, radix, ap);
490 	if (info.remain >= 1)
491 		*info.str++ = '\0';
492 	return (retval);
493 }
494 
495 void
496 kvasfree(char **strp)
497 {
498 	if (*strp) {
499 		kfree(*strp, M_TEMP);
500 		*strp = NULL;
501 	}
502 }
503 
504 static void
505 snprintf_func(int ch, void *arg)
506 {
507 	struct snprintf_arg *const info = arg;
508 
509 	if (info->remain >= 2) {
510 		*info->str++ = ch;
511 		info->remain--;
512 	}
513 }
514 
515 /*
516  * Put a NUL-terminated ASCII number (base <= 36) in a buffer in reverse
517  * order; return an optional length and a pointer to the last character
518  * written in the buffer (i.e., the first character of the string).
519  * The buffer pointed to by `nbuf' must have length >= MAXNBUF.
520  */
521 static char *
522 ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
523 {
524 	char *p, c;
525 
526 	p = nbuf;
527 	*p = '\0';
528 	do {
529 		c = hex2ascii(num % base);
530 		*++p = upper ? toupper(c) : c;
531 	} while (num /= base);
532 	if (lenp)
533 		*lenp = p - nbuf;
534 	return (p);
535 }
536 
537 /*
538  * Scaled down version of printf(3).
539  *
540  * Two additional formats:
541  *
542  * The format %b is supported to decode error registers.
543  * Its usage is:
544  *
545  *	kprintf("reg=%b\n", regval, "<base><arg>*");
546  *
547  * where <base> is the output base expressed as a control character, e.g.
548  * \10 gives octal; \20 gives hex.  Each arg is a sequence of characters,
549  * the first of which gives the bit number to be inspected (origin 1), and
550  * the next characters (up to a control character, i.e. a character <= 32),
551  * give the name of the register.  Thus:
552  *
553  *	kvcprintf("reg=%b\n", 3, "\10\2BITTWO\1BITONE\n");
554  *
555  * would produce output:
556  *
557  *	reg=3<BITTWO,BITONE>
558  *
559  * XXX:  %D  -- Hexdump, takes pointer and separator string:
560  *		("%6D", ptr, ":")   -> XX:XX:XX:XX:XX:XX
561  *		("%*D", len, ptr, " " -> XX XX XX XX ...
562  */
563 
564 #define PCHAR(c) {int cc=(c); if(func) (*func)(cc,arg); else *d++=cc; retval++;}
565 
566 int
567 kvcprintf(char const *fmt, void (*func)(int, void*), void *arg,
568 	  int radix, __va_list ap)
569 {
570 	char nbuf[MAXNBUF];
571 	char *d;
572 	const char *p, *percent, *q;
573 	u_char *up;
574 	int ch, n;
575 	uintmax_t num;
576 	int base, tmp, width, ladjust, sharpflag, neg, sign, dot;
577 	int cflag, hflag, jflag, lflag, qflag, tflag, zflag;
578 	int dwidth, upper;
579 	char padc;
580 	int retval = 0, stop = 0;
581 	int usespin;
582 
583 	/*
584 	 * Make a supreme effort to avoid reentrant panics or deadlocks.
585 	 *
586 	 * NOTE!  Do nothing that would access mycpu/gd/fs unless the
587 	 *	  function is the normal kputchar(), which allows us to
588 	 *	  use this function for very early debugging with a special
589 	 *	  function.
590 	 */
591 	if (func == kputchar) {
592 		if (mycpu->gd_flags & GDF_KPRINTF)
593 			return(0);
594 		atomic_set_long(&mycpu->gd_flags, GDF_KPRINTF);
595 	}
596 
597 	num = 0;
598 	if (!func)
599 		d = (char *) arg;
600 	else
601 		d = NULL;
602 
603 	if (fmt == NULL)
604 		fmt = "(fmt null)\n";
605 
606 	if (radix < 2 || radix > 36)
607 		radix = 10;
608 
609 	usespin = (func == kputchar &&
610 		   panic_cpu_gd != mycpu &&
611 		   (((struct putchar_arg *)arg)->flags & TOTTY) == 0);
612 	if (usespin) {
613 		crit_enter_hard();
614 		spin_lock(&cons_spin);
615 	}
616 
617 	for (;;) {
618 		padc = ' ';
619 		width = 0;
620 		while ((ch = (u_char)*fmt++) != '%' || stop) {
621 			if (ch == '\0')
622 				goto done;
623 			PCHAR(ch);
624 		}
625 		percent = fmt - 1;
626 		dot = dwidth = ladjust = neg = sharpflag = sign = upper = 0;
627 		cflag = hflag = jflag = lflag = qflag = tflag = zflag = 0;
628 
629 reswitch:
630 		switch (ch = (u_char)*fmt++) {
631 		case '.':
632 			dot = 1;
633 			goto reswitch;
634 		case '#':
635 			sharpflag = 1;
636 			goto reswitch;
637 		case '+':
638 			sign = 1;
639 			goto reswitch;
640 		case '-':
641 			ladjust = 1;
642 			goto reswitch;
643 		case '%':
644 			PCHAR(ch);
645 			break;
646 		case '*':
647 			if (!dot) {
648 				width = __va_arg(ap, int);
649 				if (width < 0) {
650 					ladjust = !ladjust;
651 					width = -width;
652 				}
653 			} else {
654 				dwidth = __va_arg(ap, int);
655 			}
656 			goto reswitch;
657 		case '0':
658 			if (!dot) {
659 				padc = '0';
660 				goto reswitch;
661 			}
662 		case '1': case '2': case '3': case '4':
663 		case '5': case '6': case '7': case '8': case '9':
664 				for (n = 0;; ++fmt) {
665 					n = n * 10 + ch - '0';
666 					ch = *fmt;
667 					if (ch < '0' || ch > '9')
668 						break;
669 				}
670 			if (dot)
671 				dwidth = n;
672 			else
673 				width = n;
674 			goto reswitch;
675 		case 'b':
676 			num = (u_int)__va_arg(ap, int);
677 			p = __va_arg(ap, char *);
678 			for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
679 				PCHAR(*q--);
680 
681 			if (num == 0)
682 				break;
683 
684 			for (tmp = 0; *p;) {
685 				n = *p++;
686 				if (num & (1 << (n - 1))) {
687 					PCHAR(tmp ? ',' : '<');
688 					for (; (n = *p) > ' '; ++p)
689 						PCHAR(n);
690 					tmp = 1;
691 				} else
692 					for (; *p > ' '; ++p)
693 						continue;
694 			}
695 			if (tmp)
696 				PCHAR('>');
697 			break;
698 		case 'c':
699 			PCHAR(__va_arg(ap, int));
700 			break;
701 		case 'D':
702 			up = __va_arg(ap, u_char *);
703 			p = __va_arg(ap, char *);
704 			if (!width)
705 				width = 16;
706 			while(width--) {
707 				PCHAR(hex2ascii(*up >> 4));
708 				PCHAR(hex2ascii(*up & 0x0f));
709 				up++;
710 				if (width)
711 					for (q=p;*q;q++)
712 						PCHAR(*q);
713 			}
714 			break;
715 		case 'd':
716 		case 'i':
717 			base = 10;
718 			sign = 1;
719 			goto handle_sign;
720 		case 'h':
721 			if (hflag) {
722 				hflag = 0;
723 				cflag = 1;
724 			} else
725 				hflag = 1;
726 			goto reswitch;
727 		case 'j':
728 			jflag = 1;
729 			goto reswitch;
730 		case 'l':
731 			if (lflag) {
732 				lflag = 0;
733 				qflag = 1;
734 			} else
735 				lflag = 1;
736 			goto reswitch;
737 		case 'n':
738 			if (cflag)
739 				*(__va_arg(ap, char *)) = retval;
740 			else if (hflag)
741 				*(__va_arg(ap, short *)) = retval;
742 			else if (jflag)
743 				*(__va_arg(ap, intmax_t *)) = retval;
744 			else if (lflag)
745 				*(__va_arg(ap, long *)) = retval;
746 			else if (qflag)
747 				*(__va_arg(ap, quad_t *)) = retval;
748 			else
749 				*(__va_arg(ap, int *)) = retval;
750 			break;
751 		case 'o':
752 			base = 8;
753 			goto handle_nosign;
754 		case 'p':
755 			base = 16;
756 			sharpflag = (width == 0);
757 			sign = 0;
758 			num = (uintptr_t)__va_arg(ap, void *);
759 			goto number;
760 		case 'q':
761 			qflag = 1;
762 			goto reswitch;
763 		case 'r':
764 			base = radix;
765 			if (sign)
766 				goto handle_sign;
767 			goto handle_nosign;
768 		case 's':
769 			p = __va_arg(ap, char *);
770 			if (p == NULL)
771 				p = "(null)";
772 			if (!dot)
773 				n = strlen (p);
774 			else
775 				for (n = 0; n < dwidth && p[n]; n++)
776 					continue;
777 
778 			width -= n;
779 
780 			if (!ladjust && width > 0)
781 				while (width--)
782 					PCHAR(padc);
783 			while (n--)
784 				PCHAR(*p++);
785 			if (ladjust && width > 0)
786 				while (width--)
787 					PCHAR(padc);
788 			break;
789 		case 't':
790 			tflag = 1;
791 			goto reswitch;
792 		case 'u':
793 			base = 10;
794 			goto handle_nosign;
795 		case 'X':
796 			upper = 1;
797 			/* FALLTHROUGH */
798 		case 'x':
799 			base = 16;
800 			goto handle_nosign;
801 		case 'z':
802 			zflag = 1;
803 			goto reswitch;
804 handle_nosign:
805 			sign = 0;
806 			if (cflag)
807 				num = (u_char)__va_arg(ap, int);
808 			else if (hflag)
809 				num = (u_short)__va_arg(ap, int);
810 			else if (jflag)
811 				num = __va_arg(ap, uintmax_t);
812 			else if (lflag)
813 				num = __va_arg(ap, u_long);
814 			else if (qflag)
815 				num = __va_arg(ap, u_quad_t);
816 			else if (tflag)
817 				num = __va_arg(ap, ptrdiff_t);
818 			else if (zflag)
819 				num = __va_arg(ap, size_t);
820 			else
821 				num = __va_arg(ap, u_int);
822 			goto number;
823 handle_sign:
824 			if (cflag)
825 				num = (char)__va_arg(ap, int);
826 			else if (hflag)
827 				num = (short)__va_arg(ap, int);
828 			else if (jflag)
829 				num = __va_arg(ap, intmax_t);
830 			else if (lflag)
831 				num = __va_arg(ap, long);
832 			else if (qflag)
833 				num = __va_arg(ap, quad_t);
834 			else if (tflag)
835 				num = __va_arg(ap, ptrdiff_t);
836 			else if (zflag)
837 				num = __va_arg(ap, ssize_t);
838 			else
839 				num = __va_arg(ap, int);
840 number:
841 			if (sign && (intmax_t)num < 0) {
842 				neg = 1;
843 				num = -(intmax_t)num;
844 			}
845 			p = ksprintn(nbuf, num, base, &tmp, upper);
846 			if (sharpflag && num != 0) {
847 				if (base == 8)
848 					tmp++;
849 				else if (base == 16)
850 					tmp += 2;
851 			}
852 			if (neg)
853 				tmp++;
854 
855 			if (!ladjust && padc != '0' && width &&
856 			    (width -= tmp) > 0) {
857 				while (width--)
858 					PCHAR(padc);
859 			}
860 			if (neg)
861 				PCHAR('-');
862 			if (sharpflag && num != 0) {
863 				if (base == 8) {
864 					PCHAR('0');
865 				} else if (base == 16) {
866 					PCHAR('0');
867 					PCHAR('x');
868 				}
869 			}
870 			if (!ladjust && width && (width -= tmp) > 0)
871 				while (width--)
872 					PCHAR(padc);
873 
874 			while (*p)
875 				PCHAR(*p--);
876 
877 			if (ladjust && width && (width -= tmp) > 0)
878 				while (width--)
879 					PCHAR(padc);
880 
881 			break;
882 		default:
883 			while (percent < fmt)
884 				PCHAR(*percent++);
885 			/*
886 			 * Since we ignore an formatting argument it is no
887 			 * longer safe to obey the remaining formatting
888 			 * arguments as the arguments will no longer match
889 			 * the format specs.
890 			 */
891 			stop = 1;
892 			break;
893 		}
894 	}
895 done:
896 	/*
897 	 * Cleanup reentrancy issues.
898 	 */
899 	if (func == kputchar)
900 		atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
901 	if (usespin) {
902 		spin_unlock(&cons_spin);
903 		crit_exit_hard();
904 	}
905 	return (retval);
906 }
907 
908 #undef PCHAR
909 
910 /*
911  * Called from the panic code to try to get the console working
912  * again in case we paniced inside a kprintf().
913  */
914 void
915 kvcreinitspin(void)
916 {
917 	spin_init(&cons_spin);
918 	atomic_clear_long(&mycpu->gd_flags, GDF_KPRINTF);
919 }
920 
921 /*
922  * Console support thread for constty intercepts.  This is needed because
923  * console tty intercepts can block.  Instead of having kputchar() attempt
924  * to directly write to the console intercept we just force it to log
925  * and wakeup this baby to track and dump the log to constty.
926  */
927 static void
928 constty_daemon(void)
929 {
930 	int rindex = -1;
931 	int windex = -1;
932         struct msgbuf *mbp;
933 	struct tty *tp;
934 
935         EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc,
936                               constty_td, SHUTDOWN_PRI_FIRST);
937         constty_td->td_flags |= TDF_SYSTHREAD;
938 
939         for (;;) {
940                 kproc_suspend_loop();
941 
942 		crit_enter();
943 		mbp = msgbufp;
944 		if (mbp == NULL || msgbufmapped == 0 ||
945 		    windex == mbp->msg_bufx) {
946 			tsleep(constty_td, 0, "waiting", hz*60);
947 			crit_exit();
948 			continue;
949 		}
950 		windex = mbp->msg_bufx;
951 		crit_exit();
952 
953 		/*
954 		 * Get message buf FIFO indices.  rindex is tracking.
955 		 */
956 		if ((tp = constty) == NULL) {
957 			rindex = mbp->msg_bufx;
958 			continue;
959 		}
960 
961 		/*
962 		 * Don't blow up if the message buffer is broken
963 		 */
964 		if (windex < 0 || windex >= mbp->msg_size)
965 			continue;
966 		if (rindex < 0 || rindex >= mbp->msg_size)
967 			rindex = windex;
968 
969 		/*
970 		 * And dump it.  If constty gets stuck will give up.
971 		 */
972 		while (rindex != windex) {
973 			if (tputchar((uint8_t)mbp->msg_ptr[rindex], tp) < 0) {
974 				constty = NULL;
975 				rindex = mbp->msg_bufx;
976 				break;
977 			}
978 			if (++rindex >= mbp->msg_size)
979 				rindex = 0;
980                         if (tp->t_outq.c_cc >= tp->t_ohiwat) {
981 				tsleep(constty_daemon, 0, "blocked", hz / 10);
982 				if (tp->t_outq.c_cc >= tp->t_ohiwat) {
983 					rindex = windex;
984 					break;
985 				}
986 			}
987 		}
988 	}
989 }
990 
991 static struct kproc_desc constty_kp = {
992         "consttyd",
993 	constty_daemon,
994         &constty_td
995 };
996 SYSINIT(bufdaemon, SI_SUB_KTHREAD_UPDATE, SI_ORDER_ANY,
997         kproc_start, &constty_kp)
998 
999 /*
1000  * Put character in log buffer with a particular priority.
1001  *
1002  * MPSAFE
1003  */
1004 static void
1005 msglogchar(int c, int pri)
1006 {
1007 	static int lastpri = -1;
1008 	static int dangling;
1009 	char nbuf[MAXNBUF];
1010 	char *p;
1011 
1012 	if (!msgbufmapped)
1013 		return;
1014 	if (c == '\0' || c == '\r')
1015 		return;
1016 	if (pri != -1 && pri != lastpri) {
1017 		if (dangling) {
1018 			msgaddchar('\n', NULL);
1019 			dangling = 0;
1020 		}
1021 		msgaddchar('<', NULL);
1022 		for (p = ksprintn(nbuf, (uintmax_t)pri, 10, NULL, 0); *p;)
1023 			msgaddchar(*p--, NULL);
1024 		msgaddchar('>', NULL);
1025 		lastpri = pri;
1026 	}
1027 	msgaddchar(c, NULL);
1028 	if (c == '\n') {
1029 		dangling = 0;
1030 		lastpri = -1;
1031 	} else {
1032 		dangling = 1;
1033 	}
1034 }
1035 
1036 /*
1037  * Put char in log buffer.   Make sure nothing blows up beyond repair if
1038  * we have an MP race.
1039  *
1040  * MPSAFE.
1041  */
1042 static void
1043 msgaddchar(int c, void *dummy)
1044 {
1045 	struct msgbuf *mbp;
1046 	int rindex;
1047 	int windex;
1048 
1049 	if (!msgbufmapped)
1050 		return;
1051 	mbp = msgbufp;
1052 	windex = mbp->msg_bufx;
1053 	mbp->msg_ptr[windex] = c;
1054 	if (++windex >= mbp->msg_size)
1055 		windex = 0;
1056 	rindex = mbp->msg_bufr;
1057 	if (windex == rindex) {
1058 		rindex += 32;
1059 		if (rindex >= mbp->msg_size)
1060 			rindex -= mbp->msg_size;
1061 		mbp->msg_bufr = rindex;
1062 	}
1063 	mbp->msg_bufx = windex;
1064 }
1065 
1066 static void
1067 msgbufcopy(struct msgbuf *oldp)
1068 {
1069 	int pos;
1070 
1071 	pos = oldp->msg_bufr;
1072 	while (pos != oldp->msg_bufx) {
1073 		msglogchar(oldp->msg_ptr[pos], -1);
1074 		if (++pos >= oldp->msg_size)
1075 			pos = 0;
1076 	}
1077 }
1078 
1079 void
1080 msgbufinit(void *ptr, size_t size)
1081 {
1082 	char *cp;
1083 	static struct msgbuf *oldp = NULL;
1084 
1085 	size -= sizeof(*msgbufp);
1086 	cp = (char *)ptr;
1087 	msgbufp = (struct msgbuf *) (cp + size);
1088 	if (msgbufp->msg_magic != MSG_MAGIC || msgbufp->msg_size != size ||
1089 	    msgbufp->msg_bufx >= size || msgbufp->msg_bufr >= size) {
1090 		bzero(cp, size);
1091 		bzero(msgbufp, sizeof(*msgbufp));
1092 		msgbufp->msg_magic = MSG_MAGIC;
1093 		msgbufp->msg_size = (char *)msgbufp - cp;
1094 	}
1095 	msgbufp->msg_ptr = cp;
1096 	if (msgbufmapped && oldp != msgbufp)
1097 		msgbufcopy(oldp);
1098 	msgbufmapped = 1;
1099 	oldp = msgbufp;
1100 }
1101 
1102 /* Sysctls for accessing/clearing the msgbuf */
1103 
1104 static int
1105 sysctl_kern_msgbuf(SYSCTL_HANDLER_ARGS)
1106 {
1107 	struct ucred *cred;
1108 	int error;
1109 
1110 	/*
1111 	 * Only wheel or root can access the message log.
1112 	 */
1113 	if (unprivileged_read_msgbuf == 0) {
1114 		KKASSERT(req->td->td_proc);
1115 		cred = req->td->td_proc->p_ucred;
1116 
1117 		if ((cred->cr_prison || groupmember(0, cred) == 0) &&
1118 		    priv_check(req->td, PRIV_ROOT) != 0
1119 		) {
1120 			return (EPERM);
1121 		}
1122 	}
1123 
1124 	/*
1125 	 * Unwind the buffer, so that it's linear (possibly starting with
1126 	 * some initial nulls).
1127 	 */
1128 	error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr + msgbufp->msg_bufx,
1129 	    msgbufp->msg_size - msgbufp->msg_bufx, req);
1130 	if (error)
1131 		return (error);
1132 	if (msgbufp->msg_bufx > 0) {
1133 		error = sysctl_handle_opaque(oidp, msgbufp->msg_ptr,
1134 		    msgbufp->msg_bufx, req);
1135 	}
1136 	return (error);
1137 }
1138 
1139 SYSCTL_PROC(_kern, OID_AUTO, msgbuf, CTLTYPE_STRING | CTLFLAG_RD,
1140     0, 0, sysctl_kern_msgbuf, "A", "Contents of kernel message buffer");
1141 
1142 static int msgbuf_clear;
1143 
1144 static int
1145 sysctl_kern_msgbuf_clear(SYSCTL_HANDLER_ARGS)
1146 {
1147 	int error;
1148 	error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
1149 	if (!error && req->newptr) {
1150 		/* Clear the buffer and reset write pointer */
1151 		bzero(msgbufp->msg_ptr, msgbufp->msg_size);
1152 		msgbufp->msg_bufr = msgbufp->msg_bufx = 0;
1153 		msgbuf_clear = 0;
1154 	}
1155 	return (error);
1156 }
1157 
1158 SYSCTL_PROC(_kern, OID_AUTO, msgbuf_clear,
1159     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_SECURE, &msgbuf_clear, 0,
1160     sysctl_kern_msgbuf_clear, "I", "Clear kernel message buffer");
1161 
1162 #ifdef DDB
1163 
1164 DB_SHOW_COMMAND(msgbuf, db_show_msgbuf)
1165 {
1166 	int i, j;
1167 
1168 	if (!msgbufmapped) {
1169 		db_printf("msgbuf not mapped yet\n");
1170 		return;
1171 	}
1172 	db_printf("msgbufp = %p\n", msgbufp);
1173 	db_printf("magic = %x, size = %d, r= %d, w = %d, ptr = %p\n",
1174 	    msgbufp->msg_magic, msgbufp->msg_size, msgbufp->msg_bufr,
1175 	    msgbufp->msg_bufx, msgbufp->msg_ptr);
1176 	for (i = 0; i < msgbufp->msg_size; i++) {
1177 		j = (i + msgbufp->msg_bufr) % msgbufp->msg_size;
1178 		db_printf("%c", msgbufp->msg_ptr[j]);
1179 	}
1180 	db_printf("\n");
1181 }
1182 
1183 #endif /* DDB */
1184 
1185 
1186 void
1187 hexdump(const void *ptr, int length, const char *hdr, int flags)
1188 {
1189 	int i, j, k;
1190 	int cols;
1191 	const unsigned char *cp;
1192 	char delim;
1193 
1194 	if ((flags & HD_DELIM_MASK) != 0)
1195 		delim = (flags & HD_DELIM_MASK) >> 8;
1196 	else
1197 		delim = ' ';
1198 
1199 	if ((flags & HD_COLUMN_MASK) != 0)
1200 		cols = flags & HD_COLUMN_MASK;
1201 	else
1202 		cols = 16;
1203 
1204 	cp = ptr;
1205 	for (i = 0; i < length; i+= cols) {
1206 		if (hdr != NULL)
1207 			kprintf("%s", hdr);
1208 
1209 		if ((flags & HD_OMIT_COUNT) == 0)
1210 			kprintf("%04x  ", i);
1211 
1212 		if ((flags & HD_OMIT_HEX) == 0) {
1213 			for (j = 0; j < cols; j++) {
1214 				k = i + j;
1215 				if (k < length)
1216 					kprintf("%c%02x", delim, cp[k]);
1217 				else
1218 					kprintf("   ");
1219 			}
1220 		}
1221 
1222 		if ((flags & HD_OMIT_CHARS) == 0) {
1223 			kprintf("  |");
1224 			for (j = 0; j < cols; j++) {
1225 				k = i + j;
1226 				if (k >= length)
1227 					kprintf(" ");
1228 				else if (cp[k] >= ' ' && cp[k] <= '~')
1229 					kprintf("%c", cp[k]);
1230 				else
1231 					kprintf(".");
1232 			}
1233 			kprintf("|");
1234 		}
1235 		kprintf("\n");
1236 	}
1237 }
1238