xref: /freebsd/sys/kern/kern_cons.c (revision f05cddf9) 
1 /*-
2  * Copyright (c) 1988 University of Utah.
3  * Copyright (c) 1991 The Regents of the University of California.
4  * Copyright (c) 1999 Michael Smith
5  * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
6  *
7  * All rights reserved.
8  *
9  * This code is derived from software contributed to Berkeley by
10  * the Systems Programming Group of the University of Utah Computer
11  * Science Department.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 4. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  *	from: @(#)cons.c	7.2 (Berkeley) 5/9/91
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include "opt_ddb.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/lock.h>
48 #include <sys/mutex.h>
49 #include <sys/conf.h>
50 #include <sys/cons.h>
51 #include <sys/fcntl.h>
52 #include <sys/kdb.h>
53 #include <sys/kernel.h>
54 #include <sys/malloc.h>
55 #include <sys/msgbuf.h>
56 #include <sys/namei.h>
57 #include <sys/priv.h>
58 #include <sys/proc.h>
59 #include <sys/queue.h>
60 #include <sys/reboot.h>
61 #include <sys/sysctl.h>
62 #include <sys/sbuf.h>
63 #include <sys/tty.h>
64 #include <sys/uio.h>
65 #include <sys/vnode.h>
66 
67 #include <ddb/ddb.h>
68 
69 #include <machine/cpu.h>
70 #include <machine/clock.h>
71 
72 static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
73 
74 struct cn_device {
75 	STAILQ_ENTRY(cn_device) cnd_next;
76 	struct		consdev *cnd_cn;
77 };
78 
79 #define CNDEVPATHMAX	32
80 #define CNDEVTAB_SIZE	4
81 static struct cn_device cn_devtab[CNDEVTAB_SIZE];
82 static STAILQ_HEAD(, cn_device) cn_devlist =
83     STAILQ_HEAD_INITIALIZER(cn_devlist);
84 
85 int	cons_avail_mask = 0;	/* Bit mask. Each registered low level console
86 				 * which is currently unavailable for inpit
87 				 * (i.e., if it is in graphics mode) will have
88 				 * this bit cleared.
89 				 */
90 static int cn_mute;
91 static char *consbuf;			/* buffer used by `consmsgbuf' */
92 static struct callout conscallout;	/* callout for outputting to constty */
93 struct msgbuf consmsgbuf;		/* message buffer for console tty */
94 static u_char console_pausing;		/* pause after each line during probe */
95 static char *console_pausestr=
96 "<pause; press any key to proceed to next line or '.' to end pause mode>";
97 struct tty *constty;			/* pointer to console "window" tty */
98 static struct mtx cnputs_mtx;		/* Mutex for cnputs(). */
99 static int use_cnputs_mtx = 0;		/* != 0 if cnputs_mtx locking reqd. */
100 
101 static void constty_timeout(void *arg);
102 
103 static struct consdev cons_consdev;
104 DATA_SET(cons_set, cons_consdev);
105 SET_DECLARE(cons_set, struct consdev);
106 
107 void
108 cninit(void)
109 {
110 	struct consdev *best_cn, *cn, **list;
111 
112 	/*
113 	 * Check if we should mute the console (for security reasons perhaps)
114 	 * It can be changes dynamically using sysctl kern.consmute
115 	 * once we are up and going.
116 	 *
117 	 */
118         cn_mute = ((boothowto & (RB_MUTE
119 			|RB_SINGLE
120 			|RB_VERBOSE
121 			|RB_ASKNAME)) == RB_MUTE);
122 
123 	/*
124 	 * Find the first console with the highest priority.
125 	 */
126 	best_cn = NULL;
127 	SET_FOREACH(list, cons_set) {
128 		cn = *list;
129 		cnremove(cn);
130 		/* Skip cons_consdev. */
131 		if (cn->cn_ops == NULL)
132 			continue;
133 		cn->cn_ops->cn_probe(cn);
134 		if (cn->cn_pri == CN_DEAD)
135 			continue;
136 		if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
137 			best_cn = cn;
138 		if (boothowto & RB_MULTIPLE) {
139 			/*
140 			 * Initialize console, and attach to it.
141 			 */
142 			cn->cn_ops->cn_init(cn);
143 			cnadd(cn);
144 		}
145 	}
146 	if (best_cn == NULL)
147 		return;
148 	if ((boothowto & RB_MULTIPLE) == 0) {
149 		best_cn->cn_ops->cn_init(best_cn);
150 		cnadd(best_cn);
151 	}
152 	if (boothowto & RB_PAUSE)
153 		console_pausing = 1;
154 	/*
155 	 * Make the best console the preferred console.
156 	 */
157 	cnselect(best_cn);
158 }
159 
160 void
161 cninit_finish()
162 {
163 	console_pausing = 0;
164 }
165 
166 /* add a new physical console to back the virtual console */
167 int
168 cnadd(struct consdev *cn)
169 {
170 	struct cn_device *cnd;
171 	int i;
172 
173 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
174 		if (cnd->cnd_cn == cn)
175 			return (0);
176 	for (i = 0; i < CNDEVTAB_SIZE; i++) {
177 		cnd = &cn_devtab[i];
178 		if (cnd->cnd_cn == NULL)
179 			break;
180 	}
181 	if (cnd->cnd_cn != NULL)
182 		return (ENOMEM);
183 	cnd->cnd_cn = cn;
184 	if (cn->cn_name[0] == '\0') {
185 		/* XXX: it is unclear if/where this print might output */
186 		printf("WARNING: console at %p has no name\n", cn);
187 	}
188 	STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
189 	if (STAILQ_FIRST(&cn_devlist) == cnd)
190 		ttyconsdev_select(cnd->cnd_cn->cn_name);
191 
192 	/* Add device to the active mask. */
193 	cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
194 
195 	return (0);
196 }
197 
198 void
199 cnremove(struct consdev *cn)
200 {
201 	struct cn_device *cnd;
202 	int i;
203 
204 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
205 		if (cnd->cnd_cn != cn)
206 			continue;
207 		if (STAILQ_FIRST(&cn_devlist) == cnd)
208 			ttyconsdev_select(NULL);
209 		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
210 		cnd->cnd_cn = NULL;
211 
212 		/* Remove this device from available mask. */
213 		for (i = 0; i < CNDEVTAB_SIZE; i++)
214 			if (cnd == &cn_devtab[i]) {
215 				cons_avail_mask &= ~(1 << i);
216 				break;
217 			}
218 #if 0
219 		/*
220 		 * XXX
221 		 * syscons gets really confused if console resources are
222 		 * freed after the system has initialized.
223 		 */
224 		if (cn->cn_term != NULL)
225 			cn->cn_ops->cn_term(cn);
226 #endif
227 		return;
228 	}
229 }
230 
231 void
232 cnselect(struct consdev *cn)
233 {
234 	struct cn_device *cnd;
235 
236 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
237 		if (cnd->cnd_cn != cn)
238 			continue;
239 		if (cnd == STAILQ_FIRST(&cn_devlist))
240 			return;
241 		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
242 		STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
243 		ttyconsdev_select(cnd->cnd_cn->cn_name);
244 		return;
245 	}
246 }
247 
248 void
249 cnavailable(struct consdev *cn, int available)
250 {
251 	int i;
252 
253 	for (i = 0; i < CNDEVTAB_SIZE; i++) {
254 		if (cn_devtab[i].cnd_cn == cn)
255 			break;
256 	}
257 	if (available) {
258 		if (i < CNDEVTAB_SIZE)
259 			cons_avail_mask |= (1 << i);
260 		cn->cn_flags &= ~CN_FLAG_NOAVAIL;
261 	} else {
262 		if (i < CNDEVTAB_SIZE)
263 			cons_avail_mask &= ~(1 << i);
264 		cn->cn_flags |= CN_FLAG_NOAVAIL;
265 	}
266 }
267 
268 int
269 cnunavailable(void)
270 {
271 
272 	return (cons_avail_mask == 0);
273 }
274 
275 /*
276  * sysctl_kern_console() provides output parseable in conscontrol(1).
277  */
278 static int
279 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
280 {
281 	struct cn_device *cnd;
282 	struct consdev *cp, **list;
283 	char *p;
284 	int delete, error;
285 	struct sbuf *sb;
286 
287 	sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND);
288 	if (sb == NULL)
289 		return (ENOMEM);
290 	sbuf_clear(sb);
291 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
292 		sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
293 	sbuf_printf(sb, "/");
294 	SET_FOREACH(list, cons_set) {
295 		cp = *list;
296 		if (cp->cn_name[0] != '\0')
297 			sbuf_printf(sb, "%s,", cp->cn_name);
298 	}
299 	sbuf_finish(sb);
300 	error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
301 	if (error == 0 && req->newptr != NULL) {
302 		p = sbuf_data(sb);
303 		error = ENXIO;
304 		delete = 0;
305 		if (*p == '-') {
306 			delete = 1;
307 			p++;
308 		}
309 		SET_FOREACH(list, cons_set) {
310 			cp = *list;
311 			if (strcmp(p, cp->cn_name) != 0)
312 				continue;
313 			if (delete) {
314 				cnremove(cp);
315 				error = 0;
316 			} else {
317 				error = cnadd(cp);
318 				if (error == 0)
319 					cnselect(cp);
320 			}
321 			break;
322 		}
323 	}
324 	sbuf_delete(sb);
325 	return (error);
326 }
327 
328 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
329 	0, 0, sysctl_kern_console, "A", "Console device control");
330 
331 /*
332  * User has changed the state of the console muting.
333  * This may require us to open or close the device in question.
334  */
335 static int
336 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
337 {
338 	int error;
339 
340 	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
341 	if (error != 0 || req->newptr == NULL)
342 		return (error);
343 	return (error);
344 }
345 
346 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
347 	0, sizeof(cn_mute), sysctl_kern_consmute, "I",
348 	"State of the console muting");
349 
350 void
351 cngrab()
352 {
353 	struct cn_device *cnd;
354 	struct consdev *cn;
355 
356 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
357 		cn = cnd->cnd_cn;
358 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
359 			cn->cn_ops->cn_grab(cn);
360 	}
361 }
362 
363 void
364 cnungrab()
365 {
366 	struct cn_device *cnd;
367 	struct consdev *cn;
368 
369 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
370 		cn = cnd->cnd_cn;
371 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
372 			cn->cn_ops->cn_ungrab(cn);
373 	}
374 }
375 
376 /*
377  * Low level console routines.
378  */
379 int
380 cngetc(void)
381 {
382 	int c;
383 
384 	if (cn_mute)
385 		return (-1);
386 	while ((c = cncheckc()) == -1)
387 		cpu_spinwait();
388 	if (c == '\r')
389 		c = '\n';		/* console input is always ICRNL */
390 	return (c);
391 }
392 
393 int
394 cncheckc(void)
395 {
396 	struct cn_device *cnd;
397 	struct consdev *cn;
398 	int c;
399 
400 	if (cn_mute)
401 		return (-1);
402 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
403 		cn = cnd->cnd_cn;
404 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
405 			c = cn->cn_ops->cn_getc(cn);
406 			if (c != -1)
407 				return (c);
408 		}
409 	}
410 	return (-1);
411 }
412 
413 void
414 cngets(char *cp, size_t size, int visible)
415 {
416 	char *lp, *end;
417 	int c;
418 
419 	cngrab();
420 
421 	lp = cp;
422 	end = cp + size - 1;
423 	for (;;) {
424 		c = cngetc() & 0177;
425 		switch (c) {
426 		case '\n':
427 		case '\r':
428 			cnputc(c);
429 			*lp = '\0';
430 			cnungrab();
431 			return;
432 		case '\b':
433 		case '\177':
434 			if (lp > cp) {
435 				if (visible) {
436 					cnputc(c);
437 					cnputs(" \b");
438 				}
439 				lp--;
440 			}
441 			continue;
442 		case '\0':
443 			continue;
444 		default:
445 			if (lp < end) {
446 				switch (visible) {
447 				case GETS_NOECHO:
448 					break;
449 				case GETS_ECHOPASS:
450 					cnputc('*');
451 					break;
452 				default:
453 					cnputc(c);
454 					break;
455 				}
456 				*lp++ = c;
457 			}
458 		}
459 	}
460 }
461 
462 void
463 cnputc(int c)
464 {
465 	struct cn_device *cnd;
466 	struct consdev *cn;
467 	char *cp;
468 
469 	if (cn_mute || c == '\0')
470 		return;
471 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
472 		cn = cnd->cnd_cn;
473 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
474 			if (c == '\n')
475 				cn->cn_ops->cn_putc(cn, '\r');
476 			cn->cn_ops->cn_putc(cn, c);
477 		}
478 	}
479 	if (console_pausing && c == '\n' && !kdb_active) {
480 		for (cp = console_pausestr; *cp != '\0'; cp++)
481 			cnputc(*cp);
482 		cngrab();
483 		if (cngetc() == '.')
484 			console_pausing = 0;
485 		cnungrab();
486 		cnputc('\r');
487 		for (cp = console_pausestr; *cp != '\0'; cp++)
488 			cnputc(' ');
489 		cnputc('\r');
490 	}
491 }
492 
493 void
494 cnputs(char *p)
495 {
496 	int c;
497 	int unlock_reqd = 0;
498 
499 	if (use_cnputs_mtx) {
500 		mtx_lock_spin(&cnputs_mtx);
501 		unlock_reqd = 1;
502 	}
503 
504 	while ((c = *p++) != '\0')
505 		cnputc(c);
506 
507 	if (unlock_reqd)
508 		mtx_unlock_spin(&cnputs_mtx);
509 }
510 
511 static int consmsgbuf_size = 8192;
512 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
513     "Console tty buffer size");
514 
515 /*
516  * Redirect console output to a tty.
517  */
518 void
519 constty_set(struct tty *tp)
520 {
521 	int size;
522 
523 	KASSERT(tp != NULL, ("constty_set: NULL tp"));
524 	if (consbuf == NULL) {
525 		size = consmsgbuf_size;
526 		consbuf = malloc(size, M_TTYCONS, M_WAITOK);
527 		msgbuf_init(&consmsgbuf, consbuf, size);
528 		callout_init(&conscallout, 0);
529 	}
530 	constty = tp;
531 	constty_timeout(NULL);
532 }
533 
534 /*
535  * Disable console redirection to a tty.
536  */
537 void
538 constty_clear(void)
539 {
540 	int c;
541 
542 	constty = NULL;
543 	if (consbuf == NULL)
544 		return;
545 	callout_stop(&conscallout);
546 	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
547 		cnputc(c);
548 	free(consbuf, M_TTYCONS);
549 	consbuf = NULL;
550 }
551 
552 /* Times per second to check for pending console tty messages. */
553 static int constty_wakeups_per_second = 5;
554 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
555     &constty_wakeups_per_second, 0,
556     "Times per second to check for pending console tty messages");
557 
558 static void
559 constty_timeout(void *arg)
560 {
561 	int c;
562 
563 	if (constty != NULL) {
564 		tty_lock(constty);
565 		while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
566 			if (tty_putchar(constty, c) < 0) {
567 				tty_unlock(constty);
568 				constty = NULL;
569 				break;
570 			}
571 		}
572 
573 		if (constty != NULL)
574 			tty_unlock(constty);
575 	}
576 	if (constty != NULL) {
577 		callout_reset(&conscallout, hz / constty_wakeups_per_second,
578 		    constty_timeout, NULL);
579 	} else {
580 		/* Deallocate the constty buffer memory. */
581 		constty_clear();
582 	}
583 }
584 
585 static void
586 cn_drvinit(void *unused)
587 {
588 
589 	mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
590 	use_cnputs_mtx = 1;
591 }
592 
593 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
594 
595 /*
596  * Sysbeep(), if we have hardware for it
597  */
598 
599 #ifdef HAS_TIMER_SPKR
600 
601 static int beeping;
602 
603 static void
604 sysbeepstop(void *chan)
605 {
606 
607 	timer_spkr_release();
608 	beeping = 0;
609 }
610 
611 int
612 sysbeep(int pitch, int period)
613 {
614 
615 	if (timer_spkr_acquire()) {
616 		if (!beeping) {
617 			/* Something else owns it. */
618 			return (EBUSY);
619 		}
620 	}
621 	timer_spkr_setfreq(pitch);
622 	if (!beeping) {
623 		beeping = period;
624 		timeout(sysbeepstop, (void *)NULL, period);
625 	}
626 	return (0);
627 }
628 
629 #else
630 
631 /*
632  * No hardware, no sound
633  */
634 
635 int
636 sysbeep(int pitch __unused, int period __unused)
637 {
638 
639 	return (ENODEV);
640 }
641 
642 #endif
643 
644