kern_cons.c revision 185539 
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: head/sys/kern/kern_cons.c 185539 2008-12-02 02:26:15Z peter $");
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
69static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
70
71struct 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
78static struct cn_device cn_devtab[CNDEVTAB_SIZE];
79static STAILQ_HEAD(, cn_device) cn_devlist =
80    STAILQ_HEAD_INITIALIZER(cn_devlist);
81
82int	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				 */
87static int cn_mute;
88static char *consbuf;			/* buffer used by `consmsgbuf' */
89static struct callout conscallout;	/* callout for outputting to constty */
90struct msgbuf consmsgbuf;		/* message buffer for console tty */
91static u_char console_pausing;		/* pause after each line during probe */
92static char *console_pausestr=
93"<pause; press any key to proceed to next line or '.' to end pause mode>";
94struct tty *constty;			/* pointer to console "window" tty */
95static struct mtx cnputs_mtx;		/* Mutex for cnputs(). */
96static int use_cnputs_mtx = 0;		/* != 0 if cnputs_mtx locking reqd. */
97
98static void constty_timeout(void *arg);
99
100static struct consdev cons_consdev;
101DATA_SET(cons_set, cons_consdev);
102SET_DECLARE(cons_set, struct consdev);
103
104void
105cninit(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
156void
157cninit_finish()
158{
159	console_pausing = 0;
160}
161
162/* add a new physical console to back the virtual console */
163int
164cnadd(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
194void
195cnremove(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
227void
228cnselect(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
244void
245cnavailable(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
264int
265cnunavailable(void)
266{
267
268	return (cons_avail_mask == 0);
269}
270
271/*
272 * sysctl_kern_console() provides output parseable in conscontrol(1).
273 */
274static int
275sysctl_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
324SYSCTL_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 */
331static int
332sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
333{
334	int error;
335	int ocn_mute;
336
337	ocn_mute = cn_mute;
338	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
339	if (error != 0 || req->newptr == NULL)
340		return (error);
341	return (error);
342}
343
344SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
345	0, sizeof(cn_mute), sysctl_kern_consmute, "I", "");
346
347/*
348 * Low level console routines.
349 */
350int
351cngetc(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
364int
365cncheckc(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			if (cn->cn_checkc != NULL)
377				c = cn->cn_checkc(cn);
378			else
379				c = cn->cn_getc(cn);
380			if (c != -1) {
381				return (c);
382			}
383		}
384	}
385	return (-1);
386}
387
388void
389cnputc(int c)
390{
391	struct cn_device *cnd;
392	struct consdev *cn;
393	char *cp;
394
395	if (cn_mute || c == '\0')
396		return;
397	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
398		cn = cnd->cnd_cn;
399		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
400			if (c == '\n')
401				cn->cn_putc(cn, '\r');
402			cn->cn_putc(cn, c);
403		}
404	}
405	if (console_pausing && c == '\n' && !kdb_active) {
406		for (cp = console_pausestr; *cp != '\0'; cp++)
407			cnputc(*cp);
408		if (cngetc() == '.')
409			console_pausing = 0;
410		cnputc('\r');
411		for (cp = console_pausestr; *cp != '\0'; cp++)
412			cnputc(' ');
413		cnputc('\r');
414	}
415}
416
417void
418cnputs(char *p)
419{
420	int c;
421	int unlock_reqd = 0;
422
423	if (use_cnputs_mtx) {
424		mtx_lock_spin(&cnputs_mtx);
425		unlock_reqd = 1;
426	}
427
428	while ((c = *p++) != '\0')
429		cnputc(c);
430
431	if (unlock_reqd)
432		mtx_unlock_spin(&cnputs_mtx);
433}
434
435static int consmsgbuf_size = 8192;
436SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
437    "");
438
439/*
440 * Redirect console output to a tty.
441 */
442void
443constty_set(struct tty *tp)
444{
445	int size;
446
447	KASSERT(tp != NULL, ("constty_set: NULL tp"));
448	if (consbuf == NULL) {
449		size = consmsgbuf_size;
450		consbuf = malloc(size, M_TTYCONS, M_WAITOK);
451		msgbuf_init(&consmsgbuf, consbuf, size);
452		callout_init(&conscallout, 0);
453	}
454	constty = tp;
455	constty_timeout(NULL);
456}
457
458/*
459 * Disable console redirection to a tty.
460 */
461void
462constty_clear(void)
463{
464	int c;
465
466	constty = NULL;
467	if (consbuf == NULL)
468		return;
469	callout_stop(&conscallout);
470	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
471		cnputc(c);
472	free(consbuf, M_TTYCONS);
473	consbuf = NULL;
474}
475
476/* Times per second to check for pending console tty messages. */
477static int constty_wakeups_per_second = 5;
478SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
479    &constty_wakeups_per_second, 0, "");
480
481static void
482constty_timeout(void *arg)
483{
484	int c;
485
486	if (constty != NULL) {
487		tty_lock(constty);
488		while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
489			if (tty_putchar(constty, c) < 0) {
490				tty_unlock(constty);
491				constty = NULL;
492				break;
493			}
494		}
495
496		if (constty != NULL)
497			tty_unlock(constty);
498	}
499	if (constty != NULL) {
500		callout_reset(&conscallout, hz / constty_wakeups_per_second,
501		    constty_timeout, NULL);
502	} else {
503		/* Deallocate the constty buffer memory. */
504		constty_clear();
505	}
506}
507
508static void
509cn_drvinit(void *unused)
510{
511
512	mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
513	use_cnputs_mtx = 1;
514}
515
516SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
517
518/*
519 * Sysbeep(), if we have hardware for it
520 */
521
522#ifdef HAS_TIMER_SPKR
523
524static int beeping;
525
526static void
527sysbeepstop(void *chan)
528{
529
530	timer_spkr_release();
531	beeping = 0;
532}
533
534int
535sysbeep(int pitch, int period)
536{
537
538	if (timer_spkr_acquire()) {
539		if (!beeping) {
540			/* Something else owns it. */
541			return (EBUSY);
542		}
543	}
544	timer_spkr_setfreq(pitch);
545	if (!beeping) {
546		beeping = period;
547		timeout(sysbeepstop, (void *)NULL, period);
548	}
549	return (0);
550}
551
552#else
553
554/*
555 * No hardware, no sound
556 */
557
558int
559sysbeep(int pitch __unused, int period __unused)
560{
561
562	return (ENODEV);
563}
564
565#endif
566
567