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 * Copyright (c) 1999 Michael Smith
5 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
6 *
7 * All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * the Systems Programming Group of the University of Utah Computer
11 * Science Department.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * from: @(#)cons.c 7.2 (Berkeley) 5/9/91
38 */
39
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42
43 #include "opt_ddb.h"
44 #include "opt_syscons.h"
45
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/lock.h>
49 #include <sys/mutex.h>
50 #include <sys/conf.h>
51 #include <sys/cons.h>
52 #include <sys/fcntl.h>
53 #include <sys/kdb.h>
54 #include <sys/kernel.h>
55 #include <sys/malloc.h>
56 #include <sys/msgbuf.h>
57 #include <sys/namei.h>
58 #include <sys/priv.h>
59 #include <sys/proc.h>
60 #include <sys/queue.h>
61 #include <sys/reboot.h>
62 #include <sys/sysctl.h>
63 #include <sys/sbuf.h>
64 #include <sys/tty.h>
65 #include <sys/uio.h>
66 #include <sys/vnode.h>
67
68 #include <ddb/ddb.h>
69
70 #include <machine/cpu.h>
71 #include <machine/clock.h>
72
73 static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
74
75 struct cn_device {
76 STAILQ_ENTRY(cn_device) cnd_next;
77 struct consdev *cnd_cn;
78 };
79
80 #define CNDEVPATHMAX 32
81 #define CNDEVTAB_SIZE 4
82 static struct cn_device cn_devtab[CNDEVTAB_SIZE];
83 static STAILQ_HEAD(, cn_device) cn_devlist =
84 STAILQ_HEAD_INITIALIZER(cn_devlist);
85
86 int cons_avail_mask = 0; /* Bit mask. Each registered low level console
87 * which is currently unavailable for inpit
88 * (i.e., if it is in graphics mode) will have
89 * this bit cleared.
90 */
91 static int cn_mute;
92 static char *consbuf; /* buffer used by `consmsgbuf' */
93 static struct callout conscallout; /* callout for outputting to constty */
94 struct msgbuf consmsgbuf; /* message buffer for console tty */
95 static u_char console_pausing; /* pause after each line during probe */
96 static char *console_pausestr=
97 "<pause; press any key to proceed to next line or '.' to end pause mode>";
98 struct tty *constty; /* pointer to console "window" tty */
99 static struct mtx cnputs_mtx; /* Mutex for cnputs(). */
100 static int use_cnputs_mtx = 0; /* != 0 if cnputs_mtx locking reqd. */
101
102 static void constty_timeout(void *arg);
103
104 static struct consdev cons_consdev;
105 DATA_SET(cons_set, cons_consdev);
106 SET_DECLARE(cons_set, struct consdev);
107
108 void
109 cninit(void)
110 {
111 struct consdev *best_cn, *cn, **list;
112
113 /*
114 * Check if we should mute the console (for security reasons perhaps)
115 * It can be changes dynamically using sysctl kern.consmute
116 * once we are up and going.
117 *
118 */
119 cn_mute = ((boothowto & (RB_MUTE
120 |RB_SINGLE
121 |RB_VERBOSE
122 |RB_ASKNAME)) == RB_MUTE);
123
124 /*
125 * Find the first console with the highest priority.
126 */
127 best_cn = NULL;
128 SET_FOREACH(list, cons_set) {
129 cn = *list;
130 cnremove(cn);
131 /* Skip cons_consdev. */
132 if (cn->cn_ops == NULL)
133 continue;
134 cn->cn_ops->cn_probe(cn);
135 if (cn->cn_pri == CN_DEAD)
136 continue;
137 if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
138 best_cn = cn;
139 if (boothowto & RB_MULTIPLE) {
140 /*
141 * Initialize console, and attach to it.
142 */
143 cn->cn_ops->cn_init(cn);
144 cnadd(cn);
145 }
146 }
147 if (best_cn == NULL)
148 return;
149 if ((boothowto & RB_MULTIPLE) == 0) {
150 best_cn->cn_ops->cn_init(best_cn);
151 cnadd(best_cn);
152 }
153 if (boothowto & RB_PAUSE)
154 console_pausing = 1;
155 /*
156 * Make the best console the preferred console.
157 */
158 cnselect(best_cn);
159
160 #ifdef EARLY_PRINTF
161 /*
162 * Release early console.
163 */
164 early_putc = NULL;
165 #endif
166 }
167
168 void
169 cninit_finish()
170 {
171 console_pausing = 0;
172 }
173
174 /* add a new physical console to back the virtual console */
175 int
176 cnadd(struct consdev *cn)
177 {
178 struct cn_device *cnd;
179 int i;
180
181 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
182 if (cnd->cnd_cn == cn)
183 return (0);
184 for (i = 0; i < CNDEVTAB_SIZE; i++) {
185 cnd = &cn_devtab[i];
186 if (cnd->cnd_cn == NULL)
187 break;
188 }
189 if (cnd->cnd_cn != NULL)
190 return (ENOMEM);
191 cnd->cnd_cn = cn;
192 if (cn->cn_name[0] == '\0') {
193 /* XXX: it is unclear if/where this print might output */
194 printf("WARNING: console at %p has no name\n", cn);
195 }
196 STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
197 if (STAILQ_FIRST(&cn_devlist) == cnd)
198 ttyconsdev_select(cnd->cnd_cn->cn_name);
199
200 /* Add device to the active mask. */
201 cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
202
203 return (0);
204 }
205
206 void
207 cnremove(struct consdev *cn)
208 {
209 struct cn_device *cnd;
210 int i;
211
212 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
213 if (cnd->cnd_cn != cn)
214 continue;
215 if (STAILQ_FIRST(&cn_devlist) == cnd)
216 ttyconsdev_select(NULL);
217 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
218 cnd->cnd_cn = NULL;
219
220 /* Remove this device from available mask. */
221 for (i = 0; i < CNDEVTAB_SIZE; i++)
222 if (cnd == &cn_devtab[i]) {
223 cons_avail_mask &= ~(1 << i);
224 break;
225 }
226 #if 0
227 /*
228 * XXX
229 * syscons gets really confused if console resources are
230 * freed after the system has initialized.
231 */
232 if (cn->cn_term != NULL)
233 cn->cn_ops->cn_term(cn);
234 #endif
235 return;
236 }
237 }
238
239 void
240 cnselect(struct consdev *cn)
241 {
242 struct cn_device *cnd;
243
244 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
245 if (cnd->cnd_cn != cn)
246 continue;
247 if (cnd == STAILQ_FIRST(&cn_devlist))
248 return;
249 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
250 STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
251 ttyconsdev_select(cnd->cnd_cn->cn_name);
252 return;
253 }
254 }
255
256 void
257 cnavailable(struct consdev *cn, int available)
258 {
259 int i;
260
261 for (i = 0; i < CNDEVTAB_SIZE; i++) {
262 if (cn_devtab[i].cnd_cn == cn)
263 break;
264 }
265 if (available) {
266 if (i < CNDEVTAB_SIZE)
267 cons_avail_mask |= (1 << i);
268 cn->cn_flags &= ~CN_FLAG_NOAVAIL;
269 } else {
270 if (i < CNDEVTAB_SIZE)
271 cons_avail_mask &= ~(1 << i);
272 cn->cn_flags |= CN_FLAG_NOAVAIL;
273 }
274 }
275
276 int
277 cnunavailable(void)
278 {
279
280 return (cons_avail_mask == 0);
281 }
282
283 /*
284 * sysctl_kern_console() provides output parseable in conscontrol(1).
285 */
286 static int
287 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
288 {
289 struct cn_device *cnd;
290 struct consdev *cp, **list;
291 char *p;
292 int delete, error;
293 struct sbuf *sb;
294
295 sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND);
296 if (sb == NULL)
297 return (ENOMEM);
298 sbuf_clear(sb);
299 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
300 sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
301 sbuf_printf(sb, "/");
302 SET_FOREACH(list, cons_set) {
303 cp = *list;
304 if (cp->cn_name[0] != '\0')
305 sbuf_printf(sb, "%s,", cp->cn_name);
306 }
307 sbuf_finish(sb);
308 error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
309 if (error == 0 && req->newptr != NULL) {
310 p = sbuf_data(sb);
311 error = ENXIO;
312 delete = 0;
313 if (*p == '-') {
314 delete = 1;
315 p++;
316 }
317 SET_FOREACH(list, cons_set) {
318 cp = *list;
319 if (strcmp(p, cp->cn_name) != 0)
320 continue;
321 if (delete) {
322 cnremove(cp);
323 error = 0;
324 } else {
325 error = cnadd(cp);
326 if (error == 0)
327 cnselect(cp);
328 }
329 break;
330 }
331 }
332 sbuf_delete(sb);
333 return (error);
334 }
335
336 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
337 0, 0, sysctl_kern_console, "A", "Console device control");
338
339 /*
340 * User has changed the state of the console muting.
341 * This may require us to open or close the device in question.
342 */
343 static int
344 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
345 {
346 int error;
347
348 error = sysctl_handle_int(oidp, &cn_mute, 0, req);
349 if (error != 0 || req->newptr == NULL)
350 return (error);
351 return (error);
352 }
353
354 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
355 0, sizeof(cn_mute), sysctl_kern_consmute, "I",
356 "State of the console muting");
357
358 void
359 cngrab()
360 {
361 struct cn_device *cnd;
362 struct consdev *cn;
363
364 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
365 cn = cnd->cnd_cn;
366 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
367 cn->cn_ops->cn_grab(cn);
368 }
369 }
370
371 void
372 cnungrab()
373 {
374 struct cn_device *cnd;
375 struct consdev *cn;
376
377 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
378 cn = cnd->cnd_cn;
379 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
380 cn->cn_ops->cn_ungrab(cn);
381 }
382 }
383
384 /*
385 * Low level console routines.
386 */
387 int
388 cngetc(void)
389 {
390 int c;
391
392 if (cn_mute)
393 return (-1);
394 while ((c = cncheckc()) == -1)
395 cpu_spinwait();
396 if (c == '\r')
397 c = '\n'; /* console input is always ICRNL */
398 return (c);
399 }
400
401 int
402 cncheckc(void)
403 {
404 struct cn_device *cnd;
405 struct consdev *cn;
406 int c;
407
408 if (cn_mute)
409 return (-1);
410 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
411 cn = cnd->cnd_cn;
412 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
413 c = cn->cn_ops->cn_getc(cn);
414 if (c != -1)
415 return (c);
416 }
417 }
418 return (-1);
419 }
420
421 void
422 cngets(char *cp, size_t size, int visible)
423 {
424 char *lp, *end;
425 int c;
426
427 cngrab();
428
429 lp = cp;
430 end = cp + size - 1;
431 for (;;) {
432 c = cngetc() & 0177;
433 switch (c) {
434 case '\n':
435 case '\r':
436 cnputc(c);
437 *lp = '\0';
438 cnungrab();
439 return;
440 case '\b':
441 case '\177':
442 if (lp > cp) {
443 if (visible)
444 cnputs("\b \b");
445 lp--;
446 }
447 continue;
448 case '\0':
449 continue;
450 default:
451 if (lp < end) {
452 switch (visible) {
453 case GETS_NOECHO:
454 break;
455 case GETS_ECHOPASS:
456 cnputc('*');
457 break;
458 default:
459 cnputc(c);
460 break;
461 }
462 *lp++ = c;
463 }
464 }
465 }
466 }
467
468 void
469 cnputc(int c)
470 {
471 struct cn_device *cnd;
472 struct consdev *cn;
473 char *cp;
474
475 #ifdef EARLY_PRINTF
476 if (early_putc != NULL) {
477 if (c == '\n')
478 early_putc('\r');
479 early_putc(c);
480 return;
481 }
482 #endif
483
484 if (cn_mute || c == '\0')
485 return;
486 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
487 cn = cnd->cnd_cn;
488 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
489 if (c == '\n')
490 cn->cn_ops->cn_putc(cn, '\r');
491 cn->cn_ops->cn_putc(cn, c);
492 }
493 }
494 if (console_pausing && c == '\n' && !kdb_active) {
495 for (cp = console_pausestr; *cp != '\0'; cp++)
496 cnputc(*cp);
497 cngrab();
498 if (cngetc() == '.')
499 console_pausing = 0;
500 cnungrab();
501 cnputc('\r');
502 for (cp = console_pausestr; *cp != '\0'; cp++)
503 cnputc(' ');
504 cnputc('\r');
505 }
506 }
507
508 void
509 cnputs(char *p)
510 {
511 int c;
512 int unlock_reqd = 0;
513
514 if (use_cnputs_mtx) {
515 /*
516 * NOTE: Debug prints and/or witness printouts in
517 * console driver clients can cause the "cnputs_mtx"
518 * mutex to recurse. Simply return if that happens.
519 */
520 if (mtx_owned(&cnputs_mtx))
521 return;
522 mtx_lock_spin(&cnputs_mtx);
523 unlock_reqd = 1;
524 }
525
526 while ((c = *p++) != '\0')
527 cnputc(c);
528
529 if (unlock_reqd)
530 mtx_unlock_spin(&cnputs_mtx);
531 }
532
533 static int consmsgbuf_size = 8192;
534 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
535 "Console tty buffer size");
536
537 /*
538 * Redirect console output to a tty.
539 */
540 void
541 constty_set(struct tty *tp)
542 {
543 int size;
544
545 KASSERT(tp != NULL, ("constty_set: NULL tp"));
546 if (consbuf == NULL) {
547 size = consmsgbuf_size;
548 consbuf = malloc(size, M_TTYCONS, M_WAITOK);
549 msgbuf_init(&consmsgbuf, consbuf, size);
550 callout_init(&conscallout, 0);
551 }
552 constty = tp;
553 constty_timeout(NULL);
554 }
555
556 /*
557 * Disable console redirection to a tty.
558 */
559 void
560 constty_clear(void)
561 {
562 int c;
563
564 constty = NULL;
565 if (consbuf == NULL)
566 return;
567 callout_stop(&conscallout);
568 while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
569 cnputc(c);
570 free(consbuf, M_TTYCONS);
571 consbuf = NULL;
572 }
573
574 /* Times per second to check for pending console tty messages. */
575 static int constty_wakeups_per_second = 5;
576 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
577 &constty_wakeups_per_second, 0,
578 "Times per second to check for pending console tty messages");
579
580 static void
581 constty_timeout(void *arg)
582 {
583 int c;
584
585 if (constty != NULL) {
586 tty_lock(constty);
587 while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
588 if (tty_putchar(constty, c) < 0) {
589 tty_unlock(constty);
590 constty = NULL;
591 break;
592 }
593 }
594
595 if (constty != NULL)
596 tty_unlock(constty);
597 }
598 if (constty != NULL) {
599 callout_reset(&conscallout, hz / constty_wakeups_per_second,
600 constty_timeout, NULL);
601 } else {
602 /* Deallocate the constty buffer memory. */
603 constty_clear();
604 }
605 }
606
607 static void
608 cn_drvinit(void *unused)
609 {
610
611 mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
612 use_cnputs_mtx = 1;
613 }
614
615 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
616
617 /*
618 * Sysbeep(), if we have hardware for it
619 */
620
621 #ifdef HAS_TIMER_SPKR
622
623 static int beeping;
624
625 static void
626 sysbeepstop(void *chan)
627 {
628
629 timer_spkr_release();
630 beeping = 0;
631 }
632
633 int
634 sysbeep(int pitch, int period)
635 {
636
637 if (timer_spkr_acquire()) {
638 if (!beeping) {
639 /* Something else owns it. */
640 return (EBUSY);
641 }
642 }
643 timer_spkr_setfreq(pitch);
644 if (!beeping) {
645 beeping = period;
646 timeout(sysbeepstop, (void *)NULL, period);
647 }
648 return (0);
649 }
650
651 #else
652
653 /*
654 * No hardware, no sound
655 */
656
657 int
658 sysbeep(int pitch __unused, int period __unused)
659 {
660
661 return (ENODEV);
662 }
663
664 #endif
665
666 /*
667 * Temporary support for sc(4) to vt(4) transition.
668 */
669 static unsigned vty_prefer;
670 static char vty_name[16];
671 SYSCTL_STRING(_kern, OID_AUTO, vty, CTLFLAG_RDTUN, vty_name, 0,
672 "Console vty driver");
673
674 int
675 vty_enabled(unsigned vty)
676 {
677 static unsigned vty_selected = 0;
678
679 if (vty_selected == 0) {
680 TUNABLE_STR_FETCH("kern.vty", vty_name, sizeof(vty_name));
681 do {
682 #if defined(DEV_SC)
683 if (strcmp(vty_name, "sc") == 0) {
684 vty_selected = VTY_SC;
685 break;
686 }
687 #endif
688 #if defined(DEV_VT)
689 if (strcmp(vty_name, "vt") == 0) {
690 vty_selected = VTY_VT;
691 break;
692 }
693 #endif
694 if (vty_prefer != 0) {
695 vty_selected = vty_prefer;
696 break;
697 }
698 #if defined(DEV_SC)
699 vty_selected = VTY_SC;
700 #elif defined(DEV_VT)
701 vty_selected = VTY_VT;
702 #endif
703 } while (0);
704
705 if (vty_selected == VTY_VT)
706 strcpy(vty_name, "vt");
707 else if (vty_selected == VTY_SC)
708 strcpy(vty_name, "sc");
709 }
710 return ((vty_selected & vty) != 0);
711 }
712
713 void
714 vty_set_preferred(unsigned vty)
715 {
716
717 vty_prefer = vty;
718 #if !defined(DEV_SC)
719 vty_prefer &= ~VTY_SC;
720 #endif
721 #if !defined(DEV_VT)
722 vty_prefer &= ~VTY_VT;
723 #endif
724 }
725
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