1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988 University of Utah.
5 * Copyright (c) 1991 The Regents of the University of California.
6 * Copyright (c) 1999 Michael Smith
7 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
8 *
9 * All rights reserved.
10 *
11 * This code is derived from software contributed to Berkeley by
12 * the Systems Programming Group of the University of Utah Computer
13 * Science Department.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 * 3. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * from: @(#)cons.c 7.2 (Berkeley) 5/9/91
40 */
41
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD: stable/12/sys/kern/kern_cons.c 372339 2022-07-29 18:50:42Z dim $");
44
45 #include "opt_ddb.h"
46 #include "opt_syscons.h"
47
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/lock.h>
51 #include <sys/mutex.h>
52 #include <sys/conf.h>
53 #include <sys/cons.h>
54 #include <sys/fcntl.h>
55 #include <sys/kdb.h>
56 #include <sys/kernel.h>
57 #include <sys/malloc.h>
58 #include <sys/msgbuf.h>
59 #include <sys/namei.h>
60 #include <sys/priv.h>
61 #include <sys/proc.h>
62 #include <sys/queue.h>
63 #include <sys/reboot.h>
64 #include <sys/sysctl.h>
65 #include <sys/sbuf.h>
66 #include <sys/tty.h>
67 #include <sys/uio.h>
68 #include <sys/vnode.h>
69
70 #include <ddb/ddb.h>
71
72 #include <machine/cpu.h>
73 #include <machine/clock.h>
74
75 static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
76
77 struct cn_device {
78 STAILQ_ENTRY(cn_device) cnd_next;
79 struct consdev *cnd_cn;
80 };
81
82 #define CNDEVPATHMAX 32
83 #define CNDEVTAB_SIZE 4
84 static struct cn_device cn_devtab[CNDEVTAB_SIZE];
85 static STAILQ_HEAD(, cn_device) cn_devlist =
86 STAILQ_HEAD_INITIALIZER(cn_devlist);
87
88 int cons_avail_mask = 0; /* Bit mask. Each registered low level console
89 * which is currently unavailable for inpit
90 * (i.e., if it is in graphics mode) will have
91 * this bit cleared.
92 */
93
94 static int cn_mute;
95 SYSCTL_INT(_kern, OID_AUTO, consmute, CTLFLAG_RW, &cn_mute, 0,
96 "State of the console muting");
97
98 static char *consbuf; /* buffer used by `consmsgbuf' */
99 static struct callout conscallout; /* callout for outputting to constty */
100 struct msgbuf consmsgbuf; /* message buffer for console tty */
101 static u_char console_pausing; /* pause after each line during probe */
102 static char *console_pausestr=
103 "<pause; press any key to proceed to next line or '.' to end pause mode>";
104 struct tty *constty; /* pointer to console "window" tty */
105 static struct mtx cnputs_mtx; /* Mutex for cnputs(). */
106 static int use_cnputs_mtx = 0; /* != 0 if cnputs_mtx locking reqd. */
107
108 static void constty_timeout(void *arg);
109
110 static struct consdev cons_consdev;
111 DATA_SET(cons_set, cons_consdev);
112 SET_DECLARE(cons_set, struct consdev);
113
114 void
cninit(void)115 cninit(void)
116 {
117 struct consdev *best_cn, *cn, **list;
118
119 /*
120 * Check if we should mute the console (for security reasons perhaps)
121 * It can be changes dynamically using sysctl kern.consmute
122 * once we are up and going.
123 *
124 */
125 cn_mute = ((boothowto & (RB_MUTE
126 |RB_SINGLE
127 |RB_VERBOSE
128 |RB_ASKNAME)) == RB_MUTE);
129
130 /*
131 * Find the first console with the highest priority.
132 */
133 best_cn = NULL;
134 SET_FOREACH(list, cons_set) {
135 cn = *list;
136 cnremove(cn);
137 /* Skip cons_consdev. */
138 if (cn->cn_ops == NULL)
139 continue;
140 cn->cn_ops->cn_probe(cn);
141 if (cn->cn_pri == CN_DEAD)
142 continue;
143 if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
144 best_cn = cn;
145 if (boothowto & RB_MULTIPLE) {
146 /*
147 * Initialize console, and attach to it.
148 */
149 cn->cn_ops->cn_init(cn);
150 cnadd(cn);
151 }
152 }
153 if (best_cn == NULL)
154 return;
155 if ((boothowto & RB_MULTIPLE) == 0) {
156 best_cn->cn_ops->cn_init(best_cn);
157 cnadd(best_cn);
158 }
159 if (boothowto & RB_PAUSE)
160 console_pausing = 1;
161 /*
162 * Make the best console the preferred console.
163 */
164 cnselect(best_cn);
165
166 #ifdef EARLY_PRINTF
167 /*
168 * Release early console.
169 */
170 early_putc = NULL;
171 #endif
172 }
173
174 void
cninit_finish(void)175 cninit_finish(void)
176 {
177 console_pausing = 0;
178 }
179
180 /* add a new physical console to back the virtual console */
181 int
cnadd(struct consdev * cn)182 cnadd(struct consdev *cn)
183 {
184 struct cn_device *cnd;
185 int i;
186
187 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
188 if (cnd->cnd_cn == cn)
189 return (0);
190 for (i = 0; i < CNDEVTAB_SIZE; i++) {
191 cnd = &cn_devtab[i];
192 if (cnd->cnd_cn == NULL)
193 break;
194 }
195 if (cnd->cnd_cn != NULL)
196 return (ENOMEM);
197 cnd->cnd_cn = cn;
198 if (cn->cn_name[0] == '\0') {
199 /* XXX: it is unclear if/where this print might output */
200 printf("WARNING: console at %p has no name\n", cn);
201 }
202 STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
203 if (STAILQ_FIRST(&cn_devlist) == cnd)
204 ttyconsdev_select(cnd->cnd_cn->cn_name);
205
206 /* Add device to the active mask. */
207 cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
208
209 return (0);
210 }
211
212 void
cnremove(struct consdev * cn)213 cnremove(struct consdev *cn)
214 {
215 struct cn_device *cnd;
216 int i;
217
218 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
219 if (cnd->cnd_cn != cn)
220 continue;
221 if (STAILQ_FIRST(&cn_devlist) == cnd)
222 ttyconsdev_select(NULL);
223 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
224 cnd->cnd_cn = NULL;
225
226 /* Remove this device from available mask. */
227 for (i = 0; i < CNDEVTAB_SIZE; i++)
228 if (cnd == &cn_devtab[i]) {
229 cons_avail_mask &= ~(1 << i);
230 break;
231 }
232 #if 0
233 /*
234 * XXX
235 * syscons gets really confused if console resources are
236 * freed after the system has initialized.
237 */
238 if (cn->cn_term != NULL)
239 cn->cn_ops->cn_term(cn);
240 #endif
241 return;
242 }
243 }
244
245 void
cnselect(struct consdev * cn)246 cnselect(struct consdev *cn)
247 {
248 struct cn_device *cnd;
249
250 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
251 if (cnd->cnd_cn != cn)
252 continue;
253 if (cnd == STAILQ_FIRST(&cn_devlist))
254 return;
255 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
256 STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
257 ttyconsdev_select(cnd->cnd_cn->cn_name);
258 return;
259 }
260 }
261
262 void
cnavailable(struct consdev * cn,int available)263 cnavailable(struct consdev *cn, int available)
264 {
265 int i;
266
267 for (i = 0; i < CNDEVTAB_SIZE; i++) {
268 if (cn_devtab[i].cnd_cn == cn)
269 break;
270 }
271 if (available) {
272 if (i < CNDEVTAB_SIZE)
273 cons_avail_mask |= (1 << i);
274 cn->cn_flags &= ~CN_FLAG_NOAVAIL;
275 } else {
276 if (i < CNDEVTAB_SIZE)
277 cons_avail_mask &= ~(1 << i);
278 cn->cn_flags |= CN_FLAG_NOAVAIL;
279 }
280 }
281
282 int
cnunavailable(void)283 cnunavailable(void)
284 {
285
286 return (cons_avail_mask == 0);
287 }
288
289 /*
290 * sysctl_kern_console() provides output parseable in conscontrol(1).
291 */
292 static int
sysctl_kern_console(SYSCTL_HANDLER_ARGS)293 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
294 {
295 struct cn_device *cnd;
296 struct consdev *cp, **list;
297 char *p;
298 int delete, error;
299 struct sbuf *sb;
300
301 sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND |
302 SBUF_INCLUDENUL);
303 if (sb == NULL)
304 return (ENOMEM);
305 sbuf_clear(sb);
306 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
307 sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
308 sbuf_printf(sb, "/");
309 SET_FOREACH(list, cons_set) {
310 cp = *list;
311 if (cp->cn_name[0] != '\0')
312 sbuf_printf(sb, "%s,", cp->cn_name);
313 }
314 sbuf_finish(sb);
315 error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
316 if (error == 0 && req->newptr != NULL) {
317 p = sbuf_data(sb);
318 error = ENXIO;
319 delete = 0;
320 if (*p == '-') {
321 delete = 1;
322 p++;
323 }
324 SET_FOREACH(list, cons_set) {
325 cp = *list;
326 if (strcmp(p, cp->cn_name) != 0)
327 continue;
328 if (delete) {
329 cnremove(cp);
330 error = 0;
331 } else {
332 error = cnadd(cp);
333 if (error == 0)
334 cnselect(cp);
335 }
336 break;
337 }
338 }
339 sbuf_delete(sb);
340 return (error);
341 }
342
343 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
344 0, 0, sysctl_kern_console, "A", "Console device control");
345
346 void
cngrab(void)347 cngrab(void)
348 {
349 struct cn_device *cnd;
350 struct consdev *cn;
351
352 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
353 cn = cnd->cnd_cn;
354 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
355 cn->cn_ops->cn_grab(cn);
356 }
357 }
358
359 void
cnungrab(void)360 cnungrab(void)
361 {
362 struct cn_device *cnd;
363 struct consdev *cn;
364
365 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
366 cn = cnd->cnd_cn;
367 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
368 cn->cn_ops->cn_ungrab(cn);
369 }
370 }
371
372 void
cnresume(void)373 cnresume(void)
374 {
375 struct cn_device *cnd;
376 struct consdev *cn;
377
378 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
379 cn = cnd->cnd_cn;
380 if (cn->cn_ops->cn_resume != NULL)
381 cn->cn_ops->cn_resume(cn);
382 }
383 }
384
385 /*
386 * Low level console routines.
387 */
388 int
cngetc(void)389 cngetc(void)
390 {
391 int c;
392
393 if (cn_mute)
394 return (-1);
395 while ((c = cncheckc()) == -1)
396 cpu_spinwait();
397 if (c == '\r')
398 c = '\n'; /* console input is always ICRNL */
399 return (c);
400 }
401
402 int
cncheckc(void)403 cncheckc(void)
404 {
405 struct cn_device *cnd;
406 struct consdev *cn;
407 int c;
408
409 if (cn_mute)
410 return (-1);
411 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
412 cn = cnd->cnd_cn;
413 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
414 c = cn->cn_ops->cn_getc(cn);
415 if (c != -1)
416 return (c);
417 }
418 }
419 return (-1);
420 }
421
422 void
cngets(char * cp,size_t size,int visible)423 cngets(char *cp, size_t size, int visible)
424 {
425 char *lp, *end;
426 int c;
427
428 cngrab();
429
430 lp = cp;
431 end = cp + size - 1;
432 for (;;) {
433 c = cngetc() & 0177;
434 switch (c) {
435 case '\n':
436 case '\r':
437 cnputc(c);
438 *lp = '\0';
439 cnungrab();
440 return;
441 case '\b':
442 case '\177':
443 if (lp > cp) {
444 if (visible)
445 cnputs("\b \b");
446 lp--;
447 }
448 continue;
449 case '\0':
450 continue;
451 default:
452 if (lp < end) {
453 switch (visible) {
454 case GETS_NOECHO:
455 break;
456 case GETS_ECHOPASS:
457 cnputc('*');
458 break;
459 default:
460 cnputc(c);
461 break;
462 }
463 *lp++ = c;
464 }
465 }
466 }
467 }
468
469 void
cnputc(int c)470 cnputc(int c)
471 {
472 struct cn_device *cnd;
473 struct consdev *cn;
474 char *cp;
475
476 #ifdef EARLY_PRINTF
477 if (early_putc != NULL) {
478 if (c == '\n')
479 early_putc('\r');
480 early_putc(c);
481 return;
482 }
483 #endif
484
485 if (cn_mute || c == '\0')
486 return;
487 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
488 cn = cnd->cnd_cn;
489 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
490 if (c == '\n')
491 cn->cn_ops->cn_putc(cn, '\r');
492 cn->cn_ops->cn_putc(cn, c);
493 }
494 }
495 if (console_pausing && c == '\n' && !kdb_active) {
496 for (cp = console_pausestr; *cp != '\0'; cp++)
497 cnputc(*cp);
498 cngrab();
499 if (cngetc() == '.')
500 console_pausing = 0;
501 cnungrab();
502 cnputc('\r');
503 for (cp = console_pausestr; *cp != '\0'; cp++)
504 cnputc(' ');
505 cnputc('\r');
506 }
507 }
508
509 void
cnputs(char * p)510 cnputs(char *p)
511 {
512 int c;
513 int unlock_reqd = 0;
514
515 if (use_cnputs_mtx) {
516 /*
517 * NOTE: Debug prints and/or witness printouts in
518 * console driver clients can cause the "cnputs_mtx"
519 * mutex to recurse. Simply return if that happens.
520 */
521 if (mtx_owned(&cnputs_mtx))
522 return;
523 mtx_lock_spin(&cnputs_mtx);
524 unlock_reqd = 1;
525 }
526
527 while ((c = *p++) != '\0')
528 cnputc(c);
529
530 if (unlock_reqd)
531 mtx_unlock_spin(&cnputs_mtx);
532 }
533
534 static int consmsgbuf_size = 8192;
535 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
536 "Console tty buffer size");
537
538 /*
539 * Redirect console output to a tty.
540 */
541 void
constty_set(struct tty * tp)542 constty_set(struct tty *tp)
543 {
544 int size;
545
546 KASSERT(tp != NULL, ("constty_set: NULL tp"));
547 if (consbuf == NULL) {
548 size = consmsgbuf_size;
549 consbuf = malloc(size, M_TTYCONS, M_WAITOK);
550 msgbuf_init(&consmsgbuf, consbuf, size);
551 callout_init(&conscallout, 0);
552 }
553 constty = tp;
554 constty_timeout(NULL);
555 }
556
557 /*
558 * Disable console redirection to a tty.
559 */
560 void
constty_clear(void)561 constty_clear(void)
562 {
563 int c;
564
565 constty = NULL;
566 if (consbuf == NULL)
567 return;
568 callout_stop(&conscallout);
569 while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
570 cnputc(c);
571 free(consbuf, M_TTYCONS);
572 consbuf = NULL;
573 }
574
575 /* Times per second to check for pending console tty messages. */
576 static int constty_wakeups_per_second = 5;
577 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
578 &constty_wakeups_per_second, 0,
579 "Times per second to check for pending console tty messages");
580
581 static void
constty_timeout(void * arg)582 constty_timeout(void *arg)
583 {
584 int c;
585
586 if (constty != NULL) {
587 tty_lock(constty);
588 while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
589 if (tty_putchar(constty, c) < 0) {
590 tty_unlock(constty);
591 constty = NULL;
592 break;
593 }
594 }
595
596 if (constty != NULL)
597 tty_unlock(constty);
598 }
599 if (constty != NULL) {
600 callout_reset(&conscallout, hz / constty_wakeups_per_second,
601 constty_timeout, NULL);
602 } else {
603 /* Deallocate the constty buffer memory. */
604 constty_clear();
605 }
606 }
607
608 static void
cn_drvinit(void * unused)609 cn_drvinit(void *unused)
610 {
611
612 mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
613 use_cnputs_mtx = 1;
614 }
615
616 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
617
618 /*
619 * Sysbeep(), if we have hardware for it
620 */
621
622 #ifdef HAS_TIMER_SPKR
623
624 static int beeping;
625 static struct callout beeping_timer;
626
627 static void
sysbeepstop(void * chan)628 sysbeepstop(void *chan)
629 {
630
631 timer_spkr_release();
632 beeping = 0;
633 }
634
635 int
sysbeep(int pitch,int period)636 sysbeep(int pitch, int period)
637 {
638
639 if (timer_spkr_acquire()) {
640 if (!beeping) {
641 /* Something else owns it. */
642 return (EBUSY);
643 }
644 }
645 timer_spkr_setfreq(pitch);
646 if (!beeping) {
647 beeping = period;
648 callout_reset(&beeping_timer, period, sysbeepstop, NULL);
649 }
650 return (0);
651 }
652
653 static void
sysbeep_init(void * unused)654 sysbeep_init(void *unused)
655 {
656
657 callout_init(&beeping_timer, 1);
658 }
659 SYSINIT(sysbeep, SI_SUB_SOFTINTR, SI_ORDER_ANY, sysbeep_init, NULL);
660 #else
661
662 /*
663 * No hardware, no sound
664 */
665
666 int
sysbeep(int pitch __unused,int period __unused)667 sysbeep(int pitch __unused, int period __unused)
668 {
669
670 return (ENODEV);
671 }
672
673 #endif
674
675 /*
676 * Temporary support for sc(4) to vt(4) transition.
677 */
678 static unsigned vty_prefer;
679 static char vty_name[16];
680 SYSCTL_STRING(_kern, OID_AUTO, vty, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, vty_name,
681 0, "Console vty driver");
682
683 int
vty_enabled(unsigned vty)684 vty_enabled(unsigned vty)
685 {
686 static unsigned vty_selected = 0;
687
688 if (vty_selected == 0) {
689 TUNABLE_STR_FETCH("kern.vty", vty_name, sizeof(vty_name));
690 do {
691 #if defined(DEV_SC)
692 if (strcmp(vty_name, "sc") == 0) {
693 vty_selected = VTY_SC;
694 break;
695 }
696 #endif
697 #if defined(DEV_VT)
698 if (strcmp(vty_name, "vt") == 0) {
699 vty_selected = VTY_VT;
700 break;
701 }
702 #endif
703 if (vty_prefer != 0) {
704 vty_selected = vty_prefer;
705 break;
706 }
707 #if defined(DEV_VT)
708 vty_selected = VTY_VT;
709 #elif defined(DEV_SC)
710 vty_selected = VTY_SC;
711 #endif
712 } while (0);
713
714 if (vty_selected == VTY_VT)
715 strcpy(vty_name, "vt");
716 else if (vty_selected == VTY_SC)
717 strcpy(vty_name, "sc");
718 }
719 return ((vty_selected & vty) != 0);
720 }
721
722 void
vty_set_preferred(unsigned vty)723 vty_set_preferred(unsigned vty)
724 {
725
726 vty_prefer = vty;
727 #if !defined(DEV_SC)
728 vty_prefer &= ~VTY_SC;
729 #endif
730 #if !defined(DEV_VT)
731 vty_prefer &= ~VTY_VT;
732 #endif
733 }
734
735