kern_cons.c revision 196506 
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 196506 2009-08-24 10:53:30Z ed $");
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		/* 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
157void
158cninit_finish()
159{
160	console_pausing = 0;
161}
162
163/* add a new physical console to back the virtual console */
164int
165cnadd(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
195void
196cnremove(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
228void
229cnselect(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
245void
246cnavailable(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
265int
266cnunavailable(void)
267{
268
269	return (cons_avail_mask == 0);
270}
271
272/*
273 * sysctl_kern_console() provides output parseable in conscontrol(1).
274 */
275static int
276sysctl_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
325SYSCTL_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 */
332static int
333sysctl_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
343SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
344	0, sizeof(cn_mute), sysctl_kern_consmute, "I", "");
345
346/*
347 * Low level console routines.
348 */
349int
350cngetc(void)
351{
352	int c;
353
354	if (cn_mute)
355		return (-1);
356	while ((c = cncheckc()) == -1)
357		;
358	if (c == '\r')
359		c = '\n';		/* console input is always ICRNL */
360	return (c);
361}
362
363int
364cncheckc(void)
365{
366	struct cn_device *cnd;
367	struct consdev *cn;
368	int c;
369
370	if (cn_mute)
371		return (-1);
372	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
373		cn = cnd->cnd_cn;
374		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
375			c = cn->cn_ops->cn_getc(cn);
376			if (c != -1)
377				return (c);
378		}
379	}
380	return (-1);
381}
382
383void
384cnputc(int c)
385{
386	struct cn_device *cnd;
387	struct consdev *cn;
388	char *cp;
389
390	if (cn_mute || c == '\0')
391		return;
392	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
393		cn = cnd->cnd_cn;
394		if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
395			if (c == '\n')
396				cn->cn_ops->cn_putc(cn, '\r');
397			cn->cn_ops->cn_putc(cn, c);
398		}
399	}
400	if (console_pausing && c == '\n' && !kdb_active) {
401		for (cp = console_pausestr; *cp != '\0'; cp++)
402			cnputc(*cp);
403		if (cngetc() == '.')
404			console_pausing = 0;
405		cnputc('\r');
406		for (cp = console_pausestr; *cp != '\0'; cp++)
407			cnputc(' ');
408		cnputc('\r');
409	}
410}
411
412void
413cnputs(char *p)
414{
415	int c;
416	int unlock_reqd = 0;
417
418	if (use_cnputs_mtx) {
419		mtx_lock_spin(&cnputs_mtx);
420		unlock_reqd = 1;
421	}
422
423	while ((c = *p++) != '\0')
424		cnputc(c);
425
426	if (unlock_reqd)
427		mtx_unlock_spin(&cnputs_mtx);
428}
429
430static int consmsgbuf_size = 8192;
431SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
432    "");
433
434/*
435 * Redirect console output to a tty.
436 */
437void
438constty_set(struct tty *tp)
439{
440	int size;
441
442	KASSERT(tp != NULL, ("constty_set: NULL tp"));
443	if (consbuf == NULL) {
444		size = consmsgbuf_size;
445		consbuf = malloc(size, M_TTYCONS, M_WAITOK);
446		msgbuf_init(&consmsgbuf, consbuf, size);
447		callout_init(&conscallout, 0);
448	}
449	constty = tp;
450	constty_timeout(NULL);
451}
452
453/*
454 * Disable console redirection to a tty.
455 */
456void
457constty_clear(void)
458{
459	int c;
460
461	constty = NULL;
462	if (consbuf == NULL)
463		return;
464	callout_stop(&conscallout);
465	while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
466		cnputc(c);
467	free(consbuf, M_TTYCONS);
468	consbuf = NULL;
469}
470
471/* Times per second to check for pending console tty messages. */
472static int constty_wakeups_per_second = 5;
473SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
474    &constty_wakeups_per_second, 0, "");
475
476static void
477constty_timeout(void *arg)
478{
479	int c;
480
481	if (constty != NULL) {
482		tty_lock(constty);
483		while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
484			if (tty_putchar(constty, c) < 0) {
485				tty_unlock(constty);
486				constty = NULL;
487				break;
488			}
489		}
490
491		if (constty != NULL)
492			tty_unlock(constty);
493	}
494	if (constty != NULL) {
495		callout_reset(&conscallout, hz / constty_wakeups_per_second,
496		    constty_timeout, NULL);
497	} else {
498		/* Deallocate the constty buffer memory. */
499		constty_clear();
500	}
501}
502
503static void
504cn_drvinit(void *unused)
505{
506
507	mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
508	use_cnputs_mtx = 1;
509}
510
511SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
512
513/*
514 * Sysbeep(), if we have hardware for it
515 */
516
517#ifdef HAS_TIMER_SPKR
518
519static int beeping;
520
521static void
522sysbeepstop(void *chan)
523{
524
525	timer_spkr_release();
526	beeping = 0;
527}
528
529int
530sysbeep(int pitch, int period)
531{
532
533	if (timer_spkr_acquire()) {
534		if (!beeping) {
535			/* Something else owns it. */
536			return (EBUSY);
537		}
538	}
539	timer_spkr_setfreq(pitch);
540	if (!beeping) {
541		beeping = period;
542		timeout(sysbeepstop, (void *)NULL, period);
543	}
544	return (0);
545}
546
547#else
548
549/*
550 * No hardware, no sound
551 */
552
553int
554sysbeep(int pitch __unused, int period __unused)
555{
556
557	return (ENODEV);
558}
559
560#endif
561
562