xref: /freebsd/sys/kern/kern_cons.c (revision 830940567b49bb0c08dfaed40418999e76616909) 
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 		if (cn->cn_probe == NULL)
128 			continue;
129 		cn->cn_probe(cn);
130 		if (cn->cn_pri == CN_DEAD)
131 			continue;
132 		if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
133 			best_cn = cn;
134 		if (boothowto & RB_MULTIPLE) {
135 			/*
136 			 * Initialize console, and attach to it.
137 			 */
138 			cn->cn_init(cn);
139 			cnadd(cn);
140 		}
141 	}
142 	if (best_cn == NULL)
143 		return;
144 	if ((boothowto & RB_MULTIPLE) == 0) {
145 		best_cn->cn_init(best_cn);
146 		cnadd(best_cn);
147 	}
148 	if (boothowto & RB_PAUSE)
149 		console_pausing = 1;
150 	/*
151 	 * Make the best console the preferred console.
152 	 */
153 	cnselect(best_cn);
154 }
155 
156 void
157 cninit_finish()
158 {
159 	console_pausing = 0;
160 }
161 
162 /* add a new physical console to back the virtual console */
163 int
164 cnadd(struct consdev *cn)
165 {
166 	struct cn_device *cnd;
167 	int i;
168 
169 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
170 		if (cnd->cnd_cn == cn)
171 			return (0);
172 	for (i = 0; i < CNDEVTAB_SIZE; i++) {
173 		cnd = &cn_devtab[i];
174 		if (cnd->cnd_cn == NULL)
175 			break;
176 	}
177 	if (cnd->cnd_cn != NULL)
178 		return (ENOMEM);
179 	cnd->cnd_cn = cn;
180 	if (cn->cn_name[0] == '\0') {
181 		/* XXX: it is unclear if/where this print might output */
182 		printf("WARNING: console at %p has no name\n", cn);
183 	}
184 	STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
185 	if (STAILQ_FIRST(&cn_devlist) == cnd)
186 		ttyconsdev_select(cnd->cnd_cn->cn_name);
187 
188 	/* Add device to the active mask. */
189 	cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
190 
191 	return (0);
192 }
193 
194 void
195 cnremove(struct consdev *cn)
196 {
197 	struct cn_device *cnd;
198 	int i;
199 
200 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
201 		if (cnd->cnd_cn != cn)
202 			continue;
203 		if (STAILQ_FIRST(&cn_devlist) == cnd)
204 			ttyconsdev_select(NULL);
205 		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
206 		cnd->cnd_cn = NULL;
207 
208 		/* Remove this device from available mask. */
209 		for (i = 0; i < CNDEVTAB_SIZE; i++)
210 			if (cnd == &cn_devtab[i]) {
211 				cons_avail_mask &= ~(1 << i);
212 				break;
213 			}
214 #if 0
215 		/*
216 		 * XXX
217 		 * syscons gets really confused if console resources are
218 		 * freed after the system has initialized.
219 		 */
220 		if (cn->cn_term != NULL)
221 			cn->cn_term(cn);
222 #endif
223 		return;
224 	}
225 }
226 
227 void
228 cnselect(struct consdev *cn)
229 {
230 	struct cn_device *cnd;
231 
232 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
233 		if (cnd->cnd_cn != cn)
234 			continue;
235 		if (cnd == STAILQ_FIRST(&cn_devlist))
236 			return;
237 		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
238 		STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
239 		ttyconsdev_select(cnd->cnd_cn->cn_name);
240 		return;
241 	}
242 }
243 
244 void
245 cnavailable(struct consdev *cn, int available)
246 {
247 	int i;
248 
249 	for (i = 0; i < CNDEVTAB_SIZE; i++) {
250 		if (cn_devtab[i].cnd_cn == cn)
251 			break;
252 	}
253 	if (available) {
254 		if (i < CNDEVTAB_SIZE)
255 			cons_avail_mask |= (1 << i);
256 		cn->cn_flags &= ~CN_FLAG_NOAVAIL;
257 	} else {
258 		if (i < CNDEVTAB_SIZE)
259 			cons_avail_mask &= ~(1 << i);
260 		cn->cn_flags |= CN_FLAG_NOAVAIL;
261 	}
262 }
263 
264 int
265 cnunavailable(void)
266 {
267 
268 	return (cons_avail_mask == 0);
269 }
270 
271 /*
272  * sysctl_kern_console() provides output parseable in conscontrol(1).
273  */
274 static int
275 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
276 {
277 	struct cn_device *cnd;
278 	struct consdev *cp, **list;
279 	char *p;
280 	int delete, error;
281 	struct sbuf *sb;
282 
283 	sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND);
284 	if (sb == NULL)
285 		return (ENOMEM);
286 	sbuf_clear(sb);
287 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
288 		sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
289 	sbuf_printf(sb, "/");
290 	SET_FOREACH(list, cons_set) {
291 		cp = *list;
292 		if (cp->cn_name[0] != '\0')
293 			sbuf_printf(sb, "%s,", cp->cn_name);
294 	}
295 	sbuf_finish(sb);
296 	error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
297 	if (error == 0 && req->newptr != NULL) {
298 		p = sbuf_data(sb);
299 		error = ENXIO;
300 		delete = 0;
301 		if (*p == '-') {
302 			delete = 1;
303 			p++;
304 		}
305 		SET_FOREACH(list, cons_set) {
306 			cp = *list;
307 			if (strcmp(p, cp->cn_name) != 0)
308 				continue;
309 			if (delete) {
310 				cnremove(cp);
311 				error = 0;
312 			} else {
313 				error = cnadd(cp);
314 				if (error == 0)
315 					cnselect(cp);
316 			}
317 			break;
318 		}
319 	}
320 	sbuf_delete(sb);
321 	return (error);
322 }
323 
324 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
325 	0, 0, sysctl_kern_console, "A", "Console device control");
326 
327 /*
328  * User has changed the state of the console muting.
329  * This may require us to open or close the device in question.
330  */
331 static int
332 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
333 {
334 	int error;
335 
336 	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
337 	if (error != 0 || req->newptr == NULL)
338 		return (error);
339 	return (error);
340 }
341 
342 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
343 	0, sizeof(cn_mute), sysctl_kern_consmute, "I", "");
344 
345 /*
346  * Low level console routines.
347  */
348 int
349 cngetc(void)
350 {
351 	int c;
352 
353 	if (cn_mute)
354 		return (-1);
355 	while ((c = cncheckc()) == -1)
356 		;
357 	if (c == '\r')
358 		c = '\n';		/* console input is always ICRNL */
359 	return (c);
360 }
361 
362 int
363 cncheckc(void)
364 {
365 	struct cn_device *cnd;
366 	struct consdev *cn;
367 	int c;
368 
369 	if (cn_mute)
370 		return (-1);
371 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
372 		cn = cnd->cnd_cn;
373 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
374 			if (cn->cn_checkc != NULL)
375 				c = cn->cn_checkc(cn);
376 			else
377 				c = cn->cn_getc(cn);
378 			if (c != -1) {
379 				return (c);
380 			}
381 		}
382 	}
383 	return (-1);
384 }
385 
386 void
387 cnputc(int c)
388 {
389 	struct cn_device *cnd;
390 	struct consdev *cn;
391 	char *cp;
392 
393 	if (cn_mute || c == '\0')
394 		return;
395 	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
396 		cn = cnd->cnd_cn;
397 		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
398 			if (c == '\n')
399 				cn->cn_putc(cn, '\r');
400 			cn->cn_putc(cn, c);
401 		}
402 	}
403 	if (console_pausing && c == '\n' && !kdb_active) {
404 		for (cp = console_pausestr; *cp != '\0'; cp++)
405 			cnputc(*cp);
406 		if (cngetc() == '.')
407 			console_pausing = 0;
408 		cnputc('\r');
409 		for (cp = console_pausestr; *cp != '\0'; cp++)
410 			cnputc(' ');
411 		cnputc('\r');
412 	}
413 }
414 
415 void
416 cnputs(char *p)
417 {
418 	int c;
419 	int unlock_reqd = 0;
420 
421 	if (use_cnputs_mtx) {
422 		mtx_lock_spin(&cnputs_mtx);
423 		unlock_reqd = 1;
424 	}
425 
426 	while ((c = *p++) != '\0')
427 		cnputc(c);
428 
429 	if (unlock_reqd)
430 		mtx_unlock_spin(&cnputs_mtx);
431 }
432 
433 static int consmsgbuf_size = 8192;
434 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
435     "");
436 
437 /*
438  * Redirect console output to a tty.
439  */
440 void
441 constty_set(struct tty *tp)
442 {
443 	int size;
444 
445 	KASSERT(tp != NULL, ("constty_set: NULL tp"));
446 	if (consbuf == NULL) {
447 		size = consmsgbuf_size;
448 		consbuf = malloc(size, M_TTYCONS, M_WAITOK);
449 		msgbuf_init(&consmsgbuf, consbuf, size);
450 		callout_init(&conscallout, 0);
451 	}
452 	constty = tp;
453 	constty_timeout(NULL);
454 }
455 
456 /*
457  * Disable console redirection to a tty.
458  */
459 void
460 constty_clear(void)
461 {
462 	int c;
463 
464 	constty = NULL;
465 	if (consbuf == NULL)
466 		return;
467 	callout_stop(&conscallout);
468 	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
469 		cnputc(c);
470 	free(consbuf, M_TTYCONS);
471 	consbuf = NULL;
472 }
473 
474 /* Times per second to check for pending console tty messages. */
475 static int constty_wakeups_per_second = 5;
476 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
477     &constty_wakeups_per_second, 0, "");
478 
479 static void
480 constty_timeout(void *arg)
481 {
482 	int c;
483 
484 	if (constty != NULL) {
485 		tty_lock(constty);
486 		while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
487 			if (tty_putchar(constty, c) < 0) {
488 				tty_unlock(constty);
489 				constty = NULL;
490 				break;
491 			}
492 		}
493 
494 		if (constty != NULL)
495 			tty_unlock(constty);
496 	}
497 	if (constty != NULL) {
498 		callout_reset(&conscallout, hz / constty_wakeups_per_second,
499 		    constty_timeout, NULL);
500 	} else {
501 		/* Deallocate the constty buffer memory. */
502 		constty_clear();
503 	}
504 }
505 
506 static void
507 cn_drvinit(void *unused)
508 {
509 
510 	mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
511 	use_cnputs_mtx = 1;
512 }
513 
514 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
515 
516 /*
517  * Sysbeep(), if we have hardware for it
518  */
519 
520 #ifdef HAS_TIMER_SPKR
521 
522 static int beeping;
523 
524 static void
525 sysbeepstop(void *chan)
526 {
527 
528 	timer_spkr_release();
529 	beeping = 0;
530 }
531 
532 int
533 sysbeep(int pitch, int period)
534 {
535 
536 	if (timer_spkr_acquire()) {
537 		if (!beeping) {
538 			/* Something else owns it. */
539 			return (EBUSY);
540 		}
541 	}
542 	timer_spkr_setfreq(pitch);
543 	if (!beeping) {
544 		beeping = period;
545 		timeout(sysbeepstop, (void *)NULL, period);
546 	}
547 	return (0);
548 }
549 
550 #else
551 
552 /*
553  * No hardware, no sound
554  */
555 
556 int
557 sysbeep(int pitch __unused, int period __unused)
558 {
559 
560 	return (ENODEV);
561 }
562 
563 #endif
564 
565