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
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/lock.h>
48 #include <sys/mutex.h>
49 #include <sys/conf.h>
50 #include <sys/cons.h>
51 #include <sys/fcntl.h>
52 #include <sys/kdb.h>
53 #include <sys/kernel.h>
54 #include <sys/malloc.h>
55 #include <sys/msgbuf.h>
56 #include <sys/namei.h>
57 #include <sys/priv.h>
58 #include <sys/proc.h>
59 #include <sys/queue.h>
60 #include <sys/reboot.h>
61 #include <sys/sysctl.h>
62 #include <sys/sbuf.h>
63 #include <sys/tty.h>
64 #include <sys/uio.h>
65 #include <sys/vnode.h>
66
67 #include <ddb/ddb.h>
68
69 #include <machine/cpu.h>
70 #include <machine/clock.h>
71
72 static MALLOC_DEFINE(M_TTYCONS, "tty console", "tty console handling");
73
74 struct cn_device {
75 STAILQ_ENTRY(cn_device) cnd_next;
76 struct consdev *cnd_cn;
77 };
78
79 #define CNDEVPATHMAX 32
80 #define CNDEVTAB_SIZE 4
81 static struct cn_device cn_devtab[CNDEVTAB_SIZE];
82 static STAILQ_HEAD(, cn_device) cn_devlist =
83 STAILQ_HEAD_INITIALIZER(cn_devlist);
84
85 int cons_avail_mask = 0; /* Bit mask. Each registered low level console
86 * which is currently unavailable for inpit
87 * (i.e., if it is in graphics mode) will have
88 * this bit cleared.
89 */
90 static int cn_mute;
91 static char *consbuf; /* buffer used by `consmsgbuf' */
92 static struct callout conscallout; /* callout for outputting to constty */
93 struct msgbuf consmsgbuf; /* message buffer for console tty */
94 static u_char console_pausing; /* pause after each line during probe */
95 static char *console_pausestr=
96 "<pause; press any key to proceed to next line or '.' to end pause mode>";
97 struct tty *constty; /* pointer to console "window" tty */
98 static struct mtx cnputs_mtx; /* Mutex for cnputs(). */
99 static int use_cnputs_mtx = 0; /* != 0 if cnputs_mtx locking reqd. */
100
101 static void constty_timeout(void *arg);
102
103 static struct consdev cons_consdev;
104 DATA_SET(cons_set, cons_consdev);
105 SET_DECLARE(cons_set, struct consdev);
106
107 void
108 cninit(void)
109 {
110 struct consdev *best_cn, *cn, **list;
111
112 /*
113 * Check if we should mute the console (for security reasons perhaps)
114 * It can be changes dynamically using sysctl kern.consmute
115 * once we are up and going.
116 *
117 */
118 cn_mute = ((boothowto & (RB_MUTE
119 |RB_SINGLE
120 |RB_VERBOSE
121 |RB_ASKNAME)) == RB_MUTE);
122
123 /*
124 * Find the first console with the highest priority.
125 */
126 best_cn = NULL;
127 SET_FOREACH(list, cons_set) {
128 cn = *list;
129 cnremove(cn);
130 /* Skip cons_consdev. */
131 if (cn->cn_ops == NULL)
132 continue;
133 cn->cn_ops->cn_probe(cn);
134 if (cn->cn_pri == CN_DEAD)
135 continue;
136 if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
137 best_cn = cn;
138 if (boothowto & RB_MULTIPLE) {
139 /*
140 * Initialize console, and attach to it.
141 */
142 cn->cn_ops->cn_init(cn);
143 cnadd(cn);
144 }
145 }
146 if (best_cn == NULL)
147 return;
148 if ((boothowto & RB_MULTIPLE) == 0) {
149 best_cn->cn_ops->cn_init(best_cn);
150 cnadd(best_cn);
151 }
152 if (boothowto & RB_PAUSE)
153 console_pausing = 1;
154 /*
155 * Make the best console the preferred console.
156 */
157 cnselect(best_cn);
158 }
159
160 void
161 cninit_finish()
162 {
163 console_pausing = 0;
164 }
165
166 /* add a new physical console to back the virtual console */
167 int
168 cnadd(struct consdev *cn)
169 {
170 struct cn_device *cnd;
171 int i;
172
173 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
174 if (cnd->cnd_cn == cn)
175 return (0);
176 for (i = 0; i < CNDEVTAB_SIZE; i++) {
177 cnd = &cn_devtab[i];
178 if (cnd->cnd_cn == NULL)
179 break;
180 }
181 if (cnd->cnd_cn != NULL)
182 return (ENOMEM);
183 cnd->cnd_cn = cn;
184 if (cn->cn_name[0] == '\0') {
185 /* XXX: it is unclear if/where this print might output */
186 printf("WARNING: console at %p has no name\n", cn);
187 }
188 STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
189 if (STAILQ_FIRST(&cn_devlist) == cnd)
190 ttyconsdev_select(cnd->cnd_cn->cn_name);
191
192 /* Add device to the active mask. */
193 cnavailable(cn, (cn->cn_flags & CN_FLAG_NOAVAIL) == 0);
194
195 return (0);
196 }
197
198 void
199 cnremove(struct consdev *cn)
200 {
201 struct cn_device *cnd;
202 int i;
203
204 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
205 if (cnd->cnd_cn != cn)
206 continue;
207 if (STAILQ_FIRST(&cn_devlist) == cnd)
208 ttyconsdev_select(NULL);
209 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
210 cnd->cnd_cn = NULL;
211
212 /* Remove this device from available mask. */
213 for (i = 0; i < CNDEVTAB_SIZE; i++)
214 if (cnd == &cn_devtab[i]) {
215 cons_avail_mask &= ~(1 << i);
216 break;
217 }
218 #if 0
219 /*
220 * XXX
221 * syscons gets really confused if console resources are
222 * freed after the system has initialized.
223 */
224 if (cn->cn_term != NULL)
225 cn->cn_ops->cn_term(cn);
226 #endif
227 return;
228 }
229 }
230
231 void
232 cnselect(struct consdev *cn)
233 {
234 struct cn_device *cnd;
235
236 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
237 if (cnd->cnd_cn != cn)
238 continue;
239 if (cnd == STAILQ_FIRST(&cn_devlist))
240 return;
241 STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
242 STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
243 ttyconsdev_select(cnd->cnd_cn->cn_name);
244 return;
245 }
246 }
247
248 void
249 cnavailable(struct consdev *cn, int available)
250 {
251 int i;
252
253 for (i = 0; i < CNDEVTAB_SIZE; i++) {
254 if (cn_devtab[i].cnd_cn == cn)
255 break;
256 }
257 if (available) {
258 if (i < CNDEVTAB_SIZE)
259 cons_avail_mask |= (1 << i);
260 cn->cn_flags &= ~CN_FLAG_NOAVAIL;
261 } else {
262 if (i < CNDEVTAB_SIZE)
263 cons_avail_mask &= ~(1 << i);
264 cn->cn_flags |= CN_FLAG_NOAVAIL;
265 }
266 }
267
268 int
269 cnunavailable(void)
270 {
271
272 return (cons_avail_mask == 0);
273 }
274
275 /*
276 * sysctl_kern_console() provides output parseable in conscontrol(1).
277 */
278 static int
279 sysctl_kern_console(SYSCTL_HANDLER_ARGS)
280 {
281 struct cn_device *cnd;
282 struct consdev *cp, **list;
283 char *p;
284 int delete, error;
285 struct sbuf *sb;
286
287 sb = sbuf_new(NULL, NULL, CNDEVPATHMAX * 2, SBUF_AUTOEXTEND);
288 if (sb == NULL)
289 return (ENOMEM);
290 sbuf_clear(sb);
291 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
292 sbuf_printf(sb, "%s,", cnd->cnd_cn->cn_name);
293 sbuf_printf(sb, "/");
294 SET_FOREACH(list, cons_set) {
295 cp = *list;
296 if (cp->cn_name[0] != '\0')
297 sbuf_printf(sb, "%s,", cp->cn_name);
298 }
299 sbuf_finish(sb);
300 error = sysctl_handle_string(oidp, sbuf_data(sb), sbuf_len(sb), req);
301 if (error == 0 && req->newptr != NULL) {
302 p = sbuf_data(sb);
303 error = ENXIO;
304 delete = 0;
305 if (*p == '-') {
306 delete = 1;
307 p++;
308 }
309 SET_FOREACH(list, cons_set) {
310 cp = *list;
311 if (strcmp(p, cp->cn_name) != 0)
312 continue;
313 if (delete) {
314 cnremove(cp);
315 error = 0;
316 } else {
317 error = cnadd(cp);
318 if (error == 0)
319 cnselect(cp);
320 }
321 break;
322 }
323 }
324 sbuf_delete(sb);
325 return (error);
326 }
327
328 SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
329 0, 0, sysctl_kern_console, "A", "Console device control");
330
331 /*
332 * User has changed the state of the console muting.
333 * This may require us to open or close the device in question.
334 */
335 static int
336 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
337 {
338 int error;
339
340 error = sysctl_handle_int(oidp, &cn_mute, 0, req);
341 if (error != 0 || req->newptr == NULL)
342 return (error);
343 return (error);
344 }
345
346 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
347 0, sizeof(cn_mute), sysctl_kern_consmute, "I",
348 "State of the console muting");
349
350 void
351 cngrab()
352 {
353 struct cn_device *cnd;
354 struct consdev *cn;
355
356 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
357 cn = cnd->cnd_cn;
358 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
359 cn->cn_ops->cn_grab(cn);
360 }
361 }
362
363 void
364 cnungrab()
365 {
366 struct cn_device *cnd;
367 struct consdev *cn;
368
369 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
370 cn = cnd->cnd_cn;
371 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG))
372 cn->cn_ops->cn_ungrab(cn);
373 }
374 }
375
376 /*
377 * Low level console routines.
378 */
379 int
380 cngetc(void)
381 {
382 int c;
383
384 if (cn_mute)
385 return (-1);
386 while ((c = cncheckc()) == -1)
387 cpu_spinwait();
388 if (c == '\r')
389 c = '\n'; /* console input is always ICRNL */
390 return (c);
391 }
392
393 int
394 cncheckc(void)
395 {
396 struct cn_device *cnd;
397 struct consdev *cn;
398 int c;
399
400 if (cn_mute)
401 return (-1);
402 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
403 cn = cnd->cnd_cn;
404 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
405 c = cn->cn_ops->cn_getc(cn);
406 if (c != -1)
407 return (c);
408 }
409 }
410 return (-1);
411 }
412
413 void
414 cngets(char *cp, size_t size, int visible)
415 {
416 char *lp, *end;
417 int c;
418
419 cngrab();
420
421 lp = cp;
422 end = cp + size - 1;
423 for (;;) {
424 c = cngetc() & 0177;
425 switch (c) {
426 case '\n':
427 case '\r':
428 cnputc(c);
429 *lp = '\0';
430 cnungrab();
431 return;
432 case '\b':
433 case '\177':
434 if (lp > cp) {
435 if (visible) {
436 cnputc(c);
437 cnputs(" \b");
438 }
439 lp--;
440 }
441 continue;
442 case '\0':
443 continue;
444 default:
445 if (lp < end) {
446 switch (visible) {
447 case GETS_NOECHO:
448 break;
449 case GETS_ECHOPASS:
450 cnputc('*');
451 break;
452 default:
453 cnputc(c);
454 break;
455 }
456 *lp++ = c;
457 }
458 }
459 }
460 }
461
462 void
463 cnputc(int c)
464 {
465 struct cn_device *cnd;
466 struct consdev *cn;
467 char *cp;
468
469 if (cn_mute || c == '\0')
470 return;
471 STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
472 cn = cnd->cnd_cn;
473 if (!kdb_active || !(cn->cn_flags & CN_FLAG_NODEBUG)) {
474 if (c == '\n')
475 cn->cn_ops->cn_putc(cn, '\r');
476 cn->cn_ops->cn_putc(cn, c);
477 }
478 }
479 if (console_pausing && c == '\n' && !kdb_active) {
480 for (cp = console_pausestr; *cp != '\0'; cp++)
481 cnputc(*cp);
482 cngrab();
483 if (cngetc() == '.')
484 console_pausing = 0;
485 cnungrab();
486 cnputc('\r');
487 for (cp = console_pausestr; *cp != '\0'; cp++)
488 cnputc(' ');
489 cnputc('\r');
490 }
491 }
492
493 void
494 cnputs(char *p)
495 {
496 int c;
497 int unlock_reqd = 0;
498
499 if (use_cnputs_mtx) {
500 /*
501 * NOTE: Debug prints and/or witness printouts in
502 * console driver clients can cause the "cnputs_mtx"
503 * mutex to recurse. Simply return if that happens.
504 */
505 if (mtx_owned(&cnputs_mtx))
506 return;
507 mtx_lock_spin(&cnputs_mtx);
508 unlock_reqd = 1;
509 }
510
511 while ((c = *p++) != '\0')
512 cnputc(c);
513
514 if (unlock_reqd)
515 mtx_unlock_spin(&cnputs_mtx);
516 }
517
518 static int consmsgbuf_size = 8192;
519 SYSCTL_INT(_kern, OID_AUTO, consmsgbuf_size, CTLFLAG_RW, &consmsgbuf_size, 0,
520 "Console tty buffer size");
521
522 /*
523 * Redirect console output to a tty.
524 */
525 void
526 constty_set(struct tty *tp)
527 {
528 int size;
529
530 KASSERT(tp != NULL, ("constty_set: NULL tp"));
531 if (consbuf == NULL) {
532 size = consmsgbuf_size;
533 consbuf = malloc(size, M_TTYCONS, M_WAITOK);
534 msgbuf_init(&consmsgbuf, consbuf, size);
535 callout_init(&conscallout, 0);
536 }
537 constty = tp;
538 constty_timeout(NULL);
539 }
540
541 /*
542 * Disable console redirection to a tty.
543 */
544 void
545 constty_clear(void)
546 {
547 int c;
548
549 constty = NULL;
550 if (consbuf == NULL)
551 return;
552 callout_stop(&conscallout);
553 while ((c = msgbuf_getchar(&consmsgbuf)) != -1)
554 cnputc(c);
555 free(consbuf, M_TTYCONS);
556 consbuf = NULL;
557 }
558
559 /* Times per second to check for pending console tty messages. */
560 static int constty_wakeups_per_second = 5;
561 SYSCTL_INT(_kern, OID_AUTO, constty_wakeups_per_second, CTLFLAG_RW,
562 &constty_wakeups_per_second, 0,
563 "Times per second to check for pending console tty messages");
564
565 static void
566 constty_timeout(void *arg)
567 {
568 int c;
569
570 if (constty != NULL) {
571 tty_lock(constty);
572 while ((c = msgbuf_getchar(&consmsgbuf)) != -1) {
573 if (tty_putchar(constty, c) < 0) {
574 tty_unlock(constty);
575 constty = NULL;
576 break;
577 }
578 }
579
580 if (constty != NULL)
581 tty_unlock(constty);
582 }
583 if (constty != NULL) {
584 callout_reset(&conscallout, hz / constty_wakeups_per_second,
585 constty_timeout, NULL);
586 } else {
587 /* Deallocate the constty buffer memory. */
588 constty_clear();
589 }
590 }
591
592 static void
593 cn_drvinit(void *unused)
594 {
595
596 mtx_init(&cnputs_mtx, "cnputs_mtx", NULL, MTX_SPIN | MTX_NOWITNESS);
597 use_cnputs_mtx = 1;
598 }
599
600 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, cn_drvinit, NULL);
601
602 /*
603 * Sysbeep(), if we have hardware for it
604 */
605
606 #ifdef HAS_TIMER_SPKR
607
608 static int beeping;
609
610 static void
611 sysbeepstop(void *chan)
612 {
613
614 timer_spkr_release();
615 beeping = 0;
616 }
617
618 int
619 sysbeep(int pitch, int period)
620 {
621
622 if (timer_spkr_acquire()) {
623 if (!beeping) {
624 /* Something else owns it. */
625 return (EBUSY);
626 }
627 }
628 timer_spkr_setfreq(pitch);
629 if (!beeping) {
630 beeping = period;
631 timeout(sysbeepstop, (void *)NULL, period);
632 }
633 return (0);
634 }
635
636 #else
637
638 /*
639 * No hardware, no sound
640 */
641
642 int
643 sysbeep(int pitch __unused, int period __unused)
644 {
645
646 return (ENODEV);
647 }
648
649 #endif
650
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