xref: /freebsd/sys/kern/kern_cons.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a) 
1 /*-
2  * Copyright (c) 1988 University of Utah.
3  * Copyright (c) 1991 The Regents of the University of California.
4  * All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * the Systems Programming Group of the University of Utah Computer
8  * Science Department.
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  * 4. 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  *	from: @(#)cons.c	7.2 (Berkeley) 5/9/91
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "opt_ddb.h"
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/lock.h>
45 #include <sys/mutex.h>
46 #include <sys/conf.h>
47 #include <sys/cons.h>
48 #include <sys/fcntl.h>
49 #include <sys/kdb.h>
50 #include <sys/kernel.h>
51 #include <sys/malloc.h>
52 #include <sys/msgbuf.h>
53 #include <sys/namei.h>
54 #include <sys/priv.h>
55 #include <sys/proc.h>
56 #include <sys/queue.h>
57 #include <sys/reboot.h>
58 #include <sys/sysctl.h>
59 #include <sys/sbuf.h>
60 #include <sys/tty.h>
61 #include <sys/uio.h>
62 #include <sys/vnode.h>
63 
64 #include <ddb/ddb.h>
65 
66 #include <machine/cpu.h>
67 #include <machine/clock.h>
68 
69 static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
70 
71 struct cn_device {
72 	STAILQ_ENTRY(cn_device) cnd_next;
73 	struct		consdev *cnd_cn;
74 };
75 
76 #define CNDEVPATHMAX	32
77 #define CNDEVTAB_SIZE	4
78 static struct cn_device cn_devtab[CNDEVTAB_SIZE];
79 static STAILQ_HEAD(, cn_device) cn_devlist =
80     STAILQ_HEAD_INITIALIZER(cn_devlist);
81 
82 int	cons_avail_mask = 0;	/* Bit mask. Each registered low level console
83 				 * which is currently unavailable for inpit
84 				 * (i.e., if it is in graphics mode) will have
85 				 * this bit cleared.
86 				 */
87 static int cn_mute;
88 static char *consbuf;			/* buffer used by `consmsgbuf' */
89 static struct callout conscallout;	/* callout for outputting to constty */
90 struct msgbuf consmsgbuf;		/* message buffer for console tty */
91 static u_char console_pausing;		/* pause after each line during probe */
92 static char *console_pausestr=
93 "<pause; press any key to proceed to next line or '.' to end pause mode>";
94 struct tty *constty;			/* pointer to console "window" tty */
95 static struct mtx cnputs_mtx;		/* Mutex for cnputs(). */
96 static int use_cnputs_mtx = 0;		/* != 0 if cnputs_mtx locking reqd. */
97 
98 static void constty_timeout(void *arg);
99 
100 static struct consdev cons_consdev;
101 DATA_SET(cons_set, cons_consdev);
102 SET_DECLARE(cons_set, struct consdev);
103 
104 void
105 cninit(void)
106 {
107 	struct consdev *best_cn, *cn, **list;
108 
109 	/*
110 	 * Check if we should mute the console (for security reasons perhaps)
111 	 * It can be changes dynamically using sysctl kern.consmute
112 	 * once we are up and going.
113 	 *
114 	 */
115         cn_mute = ((boothowto & (RB_MUTE
116 			|RB_SINGLE
117 			|RB_VERBOSE
118 			|RB_ASKNAME)) == RB_MUTE);
119 
120 	/*
121 	 * Find the first console with the highest priority.
122 	 */
123 	best_cn = NULL;
124 	SET_FOREACH(list, cons_set) {
125 		cn = *list;
126 		cnremove(cn);
127 		/* Skip cons_consdev. */
128 		if (cn->cn_ops == NULL)
129 			continue;
130 		cn->cn_ops->cn_probe(cn);
131 		if (cn->cn_pri == CN_DEAD)
132 			continue;
133 		if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
134 			best_cn = cn;
135 		if (boothowto & RB_MULTIPLE) {
136 			/*
137 			 * Initialize console, and attach to it.
138 			 */
139 			cn->cn_ops->cn_init(cn);
140 			cnadd(cn);
141 		}
142 	}
143 	if (best_cn == NULL)
144 		return;
145 	if ((boothowto & RB_MULTIPLE) == 0) {
146 		best_cn->cn_ops->cn_init(best_cn);
147 		cnadd(best_cn);
148 	}
149 	if (boothowto & RB_PAUSE)
150 		console_pausing = 1;
151 	/*
152 	 * Make the best console the preferred console.
153 	 */
154 	cnselect(best_cn);
155 }
156 
157 void
158 cninit_finish()
159 {
160 	console_pausing = 0;
161 }
162 
163 /* add a new physical console to back the virtual console */
164 int
165 cnadd(struct consdev *cn)
166 {
167 	struct cn_device *cnd;
168 	int i;
169 
170 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
171 		if (cnd->cnd_cn == cn)
172 			return (0);
173 	for (i = 0; i < CNDEVTAB_SIZE; i++) {
174 		cnd = &cn_devtab[i];
175 		if (cnd->cnd_cn == NULL)
176 			break;
177 	}
178 	if (cnd->cnd_cn != NULL)
179 		return (ENOMEM);
180 	cnd->cnd_cn = cn;
181 	if (cn->cn_name[0] == '\0') {
182 		/* XXX: it is unclear if/where this print might output */
183 		printf("WARNING: console at %p has no name\n", cn);
184 	}
185 	STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
186 	if (STAILQ_FIRST(&cn_devlist) == cnd)
187 		ttyconsdev_select(cnd->cnd_cn->cn_name);
188 
189 	/* Add device to the active mask. */
190 	cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
191 
192 	return (0);
193 }
194 
195 void
196 cnremove(struct consdev *cn)
197 {
198 	struct cn_device *cnd;
199 	int i;
200 
201 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
202 		if (cnd->cnd_cn != cn)
203 			continue;
204 		if (STAILQ_FIRST(&cn_devlist) == cnd)
205 			ttyconsdev_select(NULL);
206 		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
207 		cnd->cnd_cn = NULL;
208 
209 		/* Remove this device from available mask. */
210 		for (i = 0; i < CNDEVTAB_SIZE; i++)
211 			if (cnd == &cn_devtab[i]) {
212 				cons_avail_mask &= ~(1 << i);
213 				break;
214 			}
215 #if 0
216 		/*
217 		 * XXX
218 		 * syscons gets really confused if console resources are
219 		 * freed after the system has initialized.
220 		 */
221 		if (cn->cn_term != NULL)
222 			cn->cn_ops->cn_term(cn);
223 #endif
224 		return;
225 	}
226 }
227 
228 void
229 cnselect(struct consdev *cn)
230 {
231 	struct cn_device *cnd;
232 
233 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
234 		if (cnd->cnd_cn != cn)
235 			continue;
236 		if (cnd == STAILQ_FIRST(&cn_devlist))
237 			return;
238 		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
239 		STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
240 		ttyconsdev_select(cnd->cnd_cn->cn_name);
241 		return;
242 	}
243 }
244 
245 void
246 cnavailable(struct consdev *cn, int available)
247 {
248 	int i;
249 
250 	for (i = 0; i < CNDEVTAB_SIZE; i++) {
251 		if (cn_devtab[i].cnd_cn == cn)
252 			break;
253 	}
254 	if (available) {
255 		if (i < CNDEVTAB_SIZE)
256 			cons_avail_mask |= (1 << i);
257 		cn->cn_flags &= ~CN_FLAG_NOAVAIL;
258 	} else {
259 		if (i < CNDEVTAB_SIZE)
260 			cons_avail_mask &= ~(1 << i);
261 		cn->cn_flags |= CN_FLAG_NOAVAIL;
262 	}
263 }
264 
265 int
266 cnunavailable(void)
267 {
268 
269 	return (cons_avail_mask == 0);
270 }
271 
272 /*
273  * sysctl_kern_console() provides output parseable in conscontrol(1).
274  */
275 static int
276 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
277 {
278 	struct cn_device *cnd;
279 	struct consdev *cp, **list;
280 	char *p;
281 	int delete, error;
282 	struct sbuf *sb;
283 
284 	sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND);
285 	if (sb == NULL)
286 		return (ENOMEM);
287 	sbuf_clear(sb);
288 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
289 		sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
290 	sbuf_printf(sb, "/");
291 	SET_FOREACH(list, cons_set) {
292 		cp = *list;
293 		if (cp->cn_name[0] != '\0')
294 			sbuf_printf(sb, "%s,", cp->cn_name);
295 	}
296 	sbuf_finish(sb);
297 	error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
298 	if (error == 0 && req->newptr != NULL) {
299 		p = sbuf_data(sb);
300 		error = ENXIO;
301 		delete = 0;
302 		if (*p == '-') {
303 			delete = 1;
304 			p++;
305 		}
306 		SET_FOREACH(list, cons_set) {
307 			cp = *list;
308 			if (strcmp(p, cp->cn_name) != 0)
309 				continue;
310 			if (delete) {
311 				cnremove(cp);
312 				error = 0;
313 			} else {
314 				error = cnadd(cp);
315 				if (error == 0)
316 					cnselect(cp);
317 			}
318 			break;
319 		}
320 	}
321 	sbuf_delete(sb);
322 	return (error);
323 }
324 
325 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
326 	0, 0, sysctl_kern_console, "A", "Console device control");
327 
328 /*
329  * User has changed the state of the console muting.
330  * This may require us to open or close the device in question.
331  */
332 static int
333 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
334 {
335 	int error;
336 
337 	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
338 	if (error != 0 || req->newptr == NULL)
339 		return (error);
340 	return (error);
341 }
342 
343 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
344 	0, sizeof(cn_mute), sysctl_kern_consmute, "I",
345 	"State of the console muting");
346 
347 /*
348  * Low level console routines.
349  */
350 int
351 cngetc(void)
352 {
353 	int c;
354 
355 	if (cn_mute)
356 		return (-1);
357 	while ((c = cncheckc()) == -1)
358 		;
359 	if (c == '\r')
360 		c = '\n';		/* console input is always ICRNL */
361 	return (c);
362 }
363 
364 int
365 cncheckc(void)
366 {
367 	struct cn_device *cnd;
368 	struct consdev *cn;
369 	int c;
370 
371 	if (cn_mute)
372 		return (-1);
373 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
374 		cn = cnd->cnd_cn;
375 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
376 			c = cn->cn_ops->cn_getc(cn);
377 			if (c != -1)
378 				return (c);
379 		}
380 	}
381 	return (-1);
382 }
383 
384 void
385 cnputc(int c)
386 {
387 	struct cn_device *cnd;
388 	struct consdev *cn;
389 	char *cp;
390 
391 	if (cn_mute || c == '\0')
392 		return;
393 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
394 		cn = cnd->cnd_cn;
395 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
396 			if (c == '\n')
397 				cn->cn_ops->cn_putc(cn, '\r');
398 			cn->cn_ops->cn_putc(cn, c);
399 		}
400 	}
401 	if (console_pausing && c == '\n' && !kdb_active) {
402 		for (cp = console_pausestr; *cp != '\0'; cp++)
403 			cnputc(*cp);
404 		if (cngetc() == '.')
405 			console_pausing = 0;
406 		cnputc('\r');
407 		for (cp = console_pausestr; *cp != '\0'; cp++)
408 			cnputc(' ');
409 		cnputc('\r');
410 	}
411 }
412 
413 void
414 cnputs(char *p)
415 {
416 	int c;
417 	int unlock_reqd = 0;
418 
419 	if (use_cnputs_mtx) {
420 		mtx_lock_spin(&cnputs_mtx);
421 		unlock_reqd = 1;
422 	}
423 
424 	while ((c = *p++) != '\0')
425 		cnputc(c);
426 
427 	if (unlock_reqd)
428 		mtx_unlock_spin(&cnputs_mtx);
429 }
430 
431 static int consmsgbuf_size = 8192;
432 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
433     "Console tty buffer size");
434 
435 /*
436  * Redirect console output to a tty.
437  */
438 void
439 constty_set(struct tty *tp)
440 {
441 	int size;
442 
443 	KASSERT(tp != NULL, ("constty_set: NULL tp"));
444 	if (consbuf == NULL) {
445 		size = consmsgbuf_size;
446 		consbuf = malloc(size, M_TTYCONS, M_WAITOK);
447 		msgbuf_init(&consmsgbuf, consbuf, size);
448 		callout_init(&conscallout, 0);
449 	}
450 	constty = tp;
451 	constty_timeout(NULL);
452 }
453 
454 /*
455  * Disable console redirection to a tty.
456  */
457 void
458 constty_clear(void)
459 {
460 	int c;
461 
462 	constty = NULL;
463 	if (consbuf == NULL)
464 		return;
465 	callout_stop(&conscallout);
466 	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
467 		cnputc(c);
468 	free(consbuf, M_TTYCONS);
469 	consbuf = NULL;
470 }
471 
472 /* Times per second to check for pending console tty messages. */
473 static int constty_wakeups_per_second = 5;
474 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
475     &constty_wakeups_per_second, 0,
476     "Times per second to check for pending console tty messages");
477 
478 static void
479 constty_timeout(void *arg)
480 {
481 	int c;
482 
483 	if (constty != NULL) {
484 		tty_lock(constty);
485 		while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
486 			if (tty_putchar(constty, c) < 0) {
487 				tty_unlock(constty);
488 				constty = NULL;
489 				break;
490 			}
491 		}
492 
493 		if (constty != NULL)
494 			tty_unlock(constty);
495 	}
496 	if (constty != NULL) {
497 		callout_reset(&conscallout, hz / constty_wakeups_per_second,
498 		    constty_timeout, NULL);
499 	} else {
500 		/* Deallocate the constty buffer memory. */
501 		constty_clear();
502 	}
503 }
504 
505 static void
506 cn_drvinit(void *unused)
507 {
508 
509 	mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
510 	use_cnputs_mtx = 1;
511 }
512 
513 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
514 
515 /*
516  * Sysbeep(), if we have hardware for it
517  */
518 
519 #ifdef HAS_TIMER_SPKR
520 
521 static int beeping;
522 
523 static void
524 sysbeepstop(void *chan)
525 {
526 
527 	timer_spkr_release();
528 	beeping = 0;
529 }
530 
531 int
532 sysbeep(int pitch, int period)
533 {
534 
535 	if (timer_spkr_acquire()) {
536 		if (!beeping) {
537 			/* Something else owns it. */
538 			return (EBUSY);
539 		}
540 	}
541 	timer_spkr_setfreq(pitch);
542 	if (!beeping) {
543 		beeping = period;
544 		timeout(sysbeepstop, (void *)NULL, period);
545 	}
546 	return (0);
547 }
548 
549 #else
550 
551 /*
552  * No hardware, no sound
553  */
554 
555 int
556 sysbeep(int pitch __unused, int period __unused)
557 {
558 
559 	return (ENODEV);
560 }
561 
562 #endif
563 
564