FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_cons.c
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: releng/9.0/sys/kern/kern_cons.c 211102 2010-08-09 14:48:31Z gavin $");
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
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