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: releng/10.1/sys/kern/kern_cons.c 270988 2014-09-02 22:01:14Z emaste $");
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
161 void
162 cninit_finish()
163 {
164 console_pausing = 0;
165 }
166
167 /* add a new physical console to back the virtual console */
168 int
169 cnadd(struct consdev *cn)
170 {
171 struct cn_device *cnd;
172 int i;
173
174 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
175 if (cnd->cnd_cn == cn)
176 return (0);
177 for (i = 0; i < CNDEVTAB_SIZE; i++) {
178 cnd = &cn_devtab[i];
179 if (cnd->cnd_cn == NULL)
180 break;
181 }
182 if (cnd->cnd_cn != NULL)
183 return (ENOMEM);
184 cnd->cnd_cn = cn;
185 if (cn->cn_name[0] == '\0') {
186 /* XXX: it is unclear if/where this print might output */
187 printf("WARNING: console at %p has no name\n", cn);
188 }
189 STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
190 if (STAILQ_FIRST(&cn_devlist) == cnd)
191 ttyconsdev_select(cnd->cnd_cn->cn_name);
192
193 /* Add device to the active mask. */
194 cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
195
196 return (0);
197 }
198
199 void
200 cnremove(struct consdev *cn)
201 {
202 struct cn_device *cnd;
203 int i;
204
205 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
206 if (cnd->cnd_cn != cn)
207 continue;
208 if (STAILQ_FIRST(&cn_devlist) == cnd)
209 ttyconsdev_select(NULL);
210 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
211 cnd->cnd_cn = NULL;
212
213 /* Remove this device from available mask. */
214 for (i = 0; i < CNDEVTAB_SIZE; i++)
215 if (cnd == &cn_devtab[i]) {
216 cons_avail_mask &= ~(1 << i);
217 break;
218 }
219 #if 0
220 /*
221 * XXX
222 * syscons gets really confused if console resources are
223 * freed after the system has initialized.
224 */
225 if (cn->cn_term != NULL)
226 cn->cn_ops->cn_term(cn);
227 #endif
228 return;
229 }
230 }
231
232 void
233 cnselect(struct consdev *cn)
234 {
235 struct cn_device *cnd;
236
237 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
238 if (cnd->cnd_cn != cn)
239 continue;
240 if (cnd == STAILQ_FIRST(&cn_devlist))
241 return;
242 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
243 STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
244 ttyconsdev_select(cnd->cnd_cn->cn_name);
245 return;
246 }
247 }
248
249 void
250 cnavailable(struct consdev *cn, int available)
251 {
252 int i;
253
254 for (i = 0; i < CNDEVTAB_SIZE; i++) {
255 if (cn_devtab[i].cnd_cn == cn)
256 break;
257 }
258 if (available) {
259 if (i < CNDEVTAB_SIZE)
260 cons_avail_mask |= (1 << i);
261 cn->cn_flags &= ~CN_FLAG_NOAVAIL;
262 } else {
263 if (i < CNDEVTAB_SIZE)
264 cons_avail_mask &= ~(1 << i);
265 cn->cn_flags |= CN_FLAG_NOAVAIL;
266 }
267 }
268
269 int
270 cnunavailable(void)
271 {
272
273 return (cons_avail_mask == 0);
274 }
275
276 /*
277 * sysctl_kern_console() provides output parseable in conscontrol(1).
278 */
279 static int
280 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
281 {
282 struct cn_device *cnd;
283 struct consdev *cp, **list;
284 char *p;
285 int delete, error;
286 struct sbuf *sb;
287
288 sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND);
289 if (sb == NULL)
290 return (ENOMEM);
291 sbuf_clear(sb);
292 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
293 sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
294 sbuf_printf(sb, "/");
295 SET_FOREACH(list, cons_set) {
296 cp = *list;
297 if (cp->cn_name[0] != '\0')
298 sbuf_printf(sb, "%s,", cp->cn_name);
299 }
300 sbuf_finish(sb);
301 error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
302 if (error == 0 && req->newptr != NULL) {
303 p = sbuf_data(sb);
304 error = ENXIO;
305 delete = 0;
306 if (*p == '-') {
307 delete = 1;
308 p++;
309 }
310 SET_FOREACH(list, cons_set) {
311 cp = *list;
312 if (strcmp(p, cp->cn_name) != 0)
313 continue;
314 if (delete) {
315 cnremove(cp);
316 error = 0;
317 } else {
318 error = cnadd(cp);
319 if (error == 0)
320 cnselect(cp);
321 }
322 break;
323 }
324 }
325 sbuf_delete(sb);
326 return (error);
327 }
328
329 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
330 0, 0, sysctl_kern_console, "A", "Console device control");
331
332 /*
333 * User has changed the state of the console muting.
334 * This may require us to open or close the device in question.
335 */
336 static int
337 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
338 {
339 int error;
340
341 error = sysctl_handle_int(oidp, &cn_mute, 0, req);
342 if (error != 0 || req->newptr == NULL)
343 return (error);
344 return (error);
345 }
346
347 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
348 0, sizeof(cn_mute), sysctl_kern_consmute, "I",
349 "State of the console muting");
350
351 void
352 cngrab()
353 {
354 struct cn_device *cnd;
355 struct consdev *cn;
356
357 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
358 cn = cnd->cnd_cn;
359 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
360 cn->cn_ops->cn_grab(cn);
361 }
362 }
363
364 void
365 cnungrab()
366 {
367 struct cn_device *cnd;
368 struct consdev *cn;
369
370 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
371 cn = cnd->cnd_cn;
372 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
373 cn->cn_ops->cn_ungrab(cn);
374 }
375 }
376
377 /*
378 * Low level console routines.
379 */
380 int
381 cngetc(void)
382 {
383 int c;
384
385 if (cn_mute)
386 return (-1);
387 while ((c = cncheckc()) == -1)
388 cpu_spinwait();
389 if (c == '\r')
390 c = '\n'; /* console input is always ICRNL */
391 return (c);
392 }
393
394 int
395 cncheckc(void)
396 {
397 struct cn_device *cnd;
398 struct consdev *cn;
399 int c;
400
401 if (cn_mute)
402 return (-1);
403 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
404 cn = cnd->cnd_cn;
405 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
406 c = cn->cn_ops->cn_getc(cn);
407 if (c != -1)
408 return (c);
409 }
410 }
411 return (-1);
412 }
413
414 void
415 cngets(char *cp, size_t size, int visible)
416 {
417 char *lp, *end;
418 int c;
419
420 cngrab();
421
422 lp = cp;
423 end = cp + size - 1;
424 for (;;) {
425 c = cngetc() & 0177;
426 switch (c) {
427 case '\n':
428 case '\r':
429 cnputc(c);
430 *lp = '\0';
431 cnungrab();
432 return;
433 case '\b':
434 case '\177':
435 if (lp > cp) {
436 if (visible)
437 cnputs("\b \b");
438 lp--;
439 }
440 continue;
441 case '\0':
442 continue;
443 default:
444 if (lp < end) {
445 switch (visible) {
446 case GETS_NOECHO:
447 break;
448 case GETS_ECHOPASS:
449 cnputc('*');
450 break;
451 default:
452 cnputc(c);
453 break;
454 }
455 *lp++ = c;
456 }
457 }
458 }
459 }
460
461 void
462 cnputc(int c)
463 {
464 struct cn_device *cnd;
465 struct consdev *cn;
466 char *cp;
467
468 #ifdef EARLY_PRINTF
469 if (early_putc != NULL) {
470 if (c == '\n')
471 early_putc('\r');
472 early_putc(c);
473 return;
474 }
475 #endif
476
477 if (cn_mute || c == '\0')
478 return;
479 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
480 cn = cnd->cnd_cn;
481 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
482 if (c == '\n')
483 cn->cn_ops->cn_putc(cn, '\r');
484 cn->cn_ops->cn_putc(cn, c);
485 }
486 }
487 if (console_pausing && c == '\n' && !kdb_active) {
488 for (cp = console_pausestr; *cp != '\0'; cp++)
489 cnputc(*cp);
490 cngrab();
491 if (cngetc() == '.')
492 console_pausing = 0;
493 cnungrab();
494 cnputc('\r');
495 for (cp = console_pausestr; *cp != '\0'; cp++)
496 cnputc(' ');
497 cnputc('\r');
498 }
499 }
500
501 void
502 cnputs(char *p)
503 {
504 int c;
505 int unlock_reqd = 0;
506
507 if (use_cnputs_mtx) {
508 mtx_lock_spin(&cnputs_mtx);
509 unlock_reqd = 1;
510 }
511
512 while ((c = *p++) != '\0')
513 cnputc(c);
514
515 if (unlock_reqd)
516 mtx_unlock_spin(&cnputs_mtx);
517 }
518
519 static int consmsgbuf_size = 8192;
520 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
521 "Console tty buffer size");
522
523 /*
524 * Redirect console output to a tty.
525 */
526 void
527 constty_set(struct tty *tp)
528 {
529 int size;
530
531 KASSERT(tp != NULL, ("constty_set: NULL tp"));
532 if (consbuf == NULL) {
533 size = consmsgbuf_size;
534 consbuf = malloc(size, M_TTYCONS, M_WAITOK);
535 msgbuf_init(&consmsgbuf, consbuf, size);
536 callout_init(&conscallout, 0);
537 }
538 constty = tp;
539 constty_timeout(NULL);
540 }
541
542 /*
543 * Disable console redirection to a tty.
544 */
545 void
546 constty_clear(void)
547 {
548 int c;
549
550 constty = NULL;
551 if (consbuf == NULL)
552 return;
553 callout_stop(&conscallout);
554 while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
555 cnputc(c);
556 free(consbuf, M_TTYCONS);
557 consbuf = NULL;
558 }
559
560 /* Times per second to check for pending console tty messages. */
561 static int constty_wakeups_per_second = 5;
562 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
563 &constty_wakeups_per_second, 0,
564 "Times per second to check for pending console tty messages");
565
566 static void
567 constty_timeout(void *arg)
568 {
569 int c;
570
571 if (constty != NULL) {
572 tty_lock(constty);
573 while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
574 if (tty_putchar(constty, c) < 0) {
575 tty_unlock(constty);
576 constty = NULL;
577 break;
578 }
579 }
580
581 if (constty != NULL)
582 tty_unlock(constty);
583 }
584 if (constty != NULL) {
585 callout_reset(&conscallout, hz / constty_wakeups_per_second,
586 constty_timeout, NULL);
587 } else {
588 /* Deallocate the constty buffer memory. */
589 constty_clear();
590 }
591 }
592
593 static void
594 cn_drvinit(void *unused)
595 {
596
597 mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
598 use_cnputs_mtx = 1;
599 }
600
601 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
602
603 /*
604 * Sysbeep(), if we have hardware for it
605 */
606
607 #ifdef HAS_TIMER_SPKR
608
609 static int beeping;
610
611 static void
612 sysbeepstop(void *chan)
613 {
614
615 timer_spkr_release();
616 beeping = 0;
617 }
618
619 int
620 sysbeep(int pitch, int period)
621 {
622
623 if (timer_spkr_acquire()) {
624 if (!beeping) {
625 /* Something else owns it. */
626 return (EBUSY);
627 }
628 }
629 timer_spkr_setfreq(pitch);
630 if (!beeping) {
631 beeping = period;
632 timeout(sysbeepstop, (void *)NULL, period);
633 }
634 return (0);
635 }
636
637 #else
638
639 /*
640 * No hardware, no sound
641 */
642
643 int
644 sysbeep(int pitch __unused, int period __unused)
645 {
646
647 return (ENODEV);
648 }
649
650 #endif
651
652 /*
653 * Temporary support for sc(4) to vt(4) transition.
654 */
655 static unsigned vty_prefer;
656 static char vty_name[16];
657 SYSCTL_STRING(_kern, OID_AUTO, vty, CTLFLAG_RDTUN, vty_name, 0,
658 "Console vty driver");
659
660 int
661 vty_enabled(unsigned vty)
662 {
663 static unsigned vty_selected = 0;
664
665 if (vty_selected == 0) {
666 TUNABLE_STR_FETCH("kern.vty", vty_name, sizeof(vty_name));
667 do {
668 #if defined(DEV_SC)
669 if (strcmp(vty_name, "sc") == 0) {
670 vty_selected = VTY_SC;
671 break;
672 }
673 #endif
674 #if defined(DEV_VT)
675 if (strcmp(vty_name, "vt") == 0) {
676 vty_selected = VTY_VT;
677 break;
678 }
679 #endif
680 if (vty_prefer != 0) {
681 vty_selected = vty_prefer;
682 break;
683 }
684 #if defined(DEV_SC)
685 vty_selected = VTY_SC;
686 #elif defined(DEV_VT)
687 vty_selected = VTY_VT;
688 #endif
689 } while (0);
690
691 if (vty_selected == VTY_VT)
692 strcpy(vty_name, "vt");
693 else if (vty_selected == VTY_SC)
694 strcpy(vty_name, "sc");
695 }
696 return ((vty_selected & vty) != 0);
697 }
698
699 void
700 vty_set_preferred(unsigned vty)
701 {
702
703 vty_prefer = vty;
704 #if !defined(DEV_SC)
705 vty_prefer &= ~VTY_SC;
706 #endif
707 #if !defined(DEV_VT)
708 vty_prefer &= ~VTY_VT;
709 #endif
710 }
711
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