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 * 3. 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 * $FreeBSD: src/sys/kern/tty_cons.c,v 1.81.2.4 2001/12/17 18:44:41 guido Exp $
36 */
37
38 #include "opt_ddb.h"
39 #include "opt_comconsole.h"
40
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/caps.h>
44 #include <sys/conf.h>
45 #include <sys/cons.h>
46 #include <sys/kernel.h>
47 #include <sys/proc.h>
48 #include <sys/caps.h>
49 #include <sys/reboot.h>
50 #include <sys/sysctl.h>
51 #include <sys/tty.h>
52 #include <sys/uio.h>
53 #include <sys/msgport.h>
54 #include <sys/msgport2.h>
55 #include <sys/device.h>
56
57 #include <ddb/ddb.h>
58
59 #include <machine/cpu.h>
60
61 static d_open_t cnopen;
62 static d_close_t cnclose;
63 static d_read_t cnread;
64 static d_write_t cnwrite;
65 static d_ioctl_t cnioctl;
66 static d_kqfilter_t cnkqfilter;
67
68 static int cnintercept(struct dev_generic_args *ap);
69
70 #define CDEV_MAJOR 0
71 static struct dev_ops cn_ops = {
72 { "console", 0, D_TTY | D_MPSAFE },
73 .d_open = cnopen,
74 .d_close = cnclose,
75 .d_read = cnread,
76 .d_write = cnwrite,
77 .d_ioctl = cnioctl,
78 .d_kqfilter = cnkqfilter,
79 };
80
81 static struct dev_ops cn_iops = {
82 { "intercept", 0, D_TTY | D_MPSAFE },
83 .d_default = cnintercept
84 };
85
86 static struct dev_ops *cn_fwd_ops;
87 static cdev_t cn_dev;
88
89 //XXX: get this shit out! (alexh)
90 #if 0
91 SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
92 &cn_udev, sizeof cn_udev, "T,udev_t", "");
93 #endif
94
95 static int cn_mute;
96
97 #ifdef BREAK_TO_DEBUGGER
98 int break_to_debugger = 1; /* CTL-ALT-ESC on system keyboard */
99 #else
100 int break_to_debugger = 0;
101 #endif
102 TUNABLE_INT("kern.break_to_debugger", &break_to_debugger);
103 SYSCTL_INT(_kern, OID_AUTO, break_to_debugger, CTLFLAG_RW,
104 &break_to_debugger, 0, "");
105
106 #ifdef ALT_BREAK_TO_DEBUGGER
107 int alt_break_to_debugger = 1; /* CR ~ ^B on serial port */
108 #else
109 int alt_break_to_debugger = 0;
110 #endif
111 TUNABLE_INT("kern.alt_break_to_debugger", &alt_break_to_debugger);
112 SYSCTL_INT(_kern, OID_AUTO, alt_break_to_debugger, CTLFLAG_RW,
113 &alt_break_to_debugger, 0, "");
114
115 int cons_unavail = 0; /* XXX:
116 * physical console not available for
117 * input (i.e., it is in graphics mode)
118 */
119 int sysbeep_enable = 1;
120
121 static u_char cn_is_open; /* nonzero if logical console is open */
122 static int openmode, openflag; /* how /dev/console was openned */
123 static cdev_t cn_devfsdev; /* represents the device private info */
124 static u_char cn_phys_is_open; /* nonzero if physical device is open */
125 static u_char console_pausing; /* pause after each line during probe */
126 static char *console_pausestr=
127 "<pause; press any key to proceed to next line or '.' to end pause mode>";
128
129 struct consdev *cn_tab; /* physical console device info */
130 struct consdev *gdb_tab; /* physical gdb debugger device info */
131
132 SYSCTL_INT(_kern, OID_AUTO, sysbeep_enable, CTLFLAG_RW, &sysbeep_enable, 0, "");
133 static uint32_t console_rdev;
134 SYSCTL_INT(_kern, OID_AUTO, console_rdev, CTLFLAG_RW,
135 &console_rdev, 0, "");
136
137 CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
138 SET_DECLARE(cons_set, struct consdev);
139
140 void
cninit(void)141 cninit(void)
142 {
143 struct consdev *best_cp, *cp, **list;
144
145 /*
146 * Workaround for token acquisition and releases during the
147 * console init. For some reason if lwkt_gettoken()'s mpcount
148 * optimization is turned off the console init blows up. It
149 * might be trying to kprintf() something in the middle of
150 * its init.
151 */
152 lwkt_gettoken(&tty_token);
153 lwkt_gettoken(&vga_token);
154
155 /*
156 * Check if we should mute the console (for security reasons perhaps)
157 * It can be changes dynamically using sysctl kern.consmute
158 * once we are up and going.
159 *
160 */
161 cn_mute = ((boothowto & (RB_MUTE
162 |RB_SINGLE
163 |RB_VERBOSE
164 |RB_ASKNAME)) == RB_MUTE);
165
166 /*
167 * Find the first console with the highest priority.
168 */
169 best_cp = NULL;
170 SET_FOREACH(list, cons_set) {
171 cp = *list;
172 if (cp->cn_probe == NULL)
173 continue;
174 (*cp->cn_probe)(cp);
175 if (cp->cn_pri > CN_DEAD && cp->cn_probegood &&
176 (best_cp == NULL || cp->cn_pri > best_cp->cn_pri))
177 best_cp = cp;
178 }
179
180 /*
181 * If no console, give up.
182 */
183 if (best_cp == NULL) {
184 if (cn_tab != NULL && cn_tab->cn_term != NULL)
185 (*cn_tab->cn_term)(cn_tab);
186 goto done;
187 }
188
189 /*
190 * Initialize console, then attach to it. This ordering allows
191 * debugging using the previous console, if any.
192 */
193 (*best_cp->cn_init)(best_cp);
194 if (cn_tab != NULL && cn_tab != best_cp) {
195 /* Turn off the previous console. */
196 if (cn_tab->cn_term != NULL)
197 (*cn_tab->cn_term)(cn_tab);
198 }
199 if (boothowto & RB_PAUSE)
200 console_pausing = 1;
201 done:
202 cn_tab = best_cp;
203
204 /*
205 * We can safely release the token after the init is done.
206 * Also assert that the mpcount is still correct or otherwise
207 * the SMP/AP boot will blow up on us.
208 */
209 lwkt_reltoken(&vga_token);
210 lwkt_reltoken(&tty_token);
211 }
212
213
214 /*
215 * Hook the open and close functions on the selected device.
216 */
217 void
cninit_finish(void)218 cninit_finish(void)
219 {
220 if ((cn_tab == NULL) || cn_mute)
221 return;
222 if (cn_tab->cn_dev == NULL) {
223 cn_tab->cn_init_fini(cn_tab);
224 if (cn_tab->cn_dev == NULL) {
225 kprintf("Unable to hook console! cn_tab %p\n", cn_tab);
226 return;
227 }
228 }
229
230 cn_fwd_ops = dev_ops_intercept(cn_tab->cn_dev, &cn_iops);
231 cn_dev = cn_tab->cn_dev;
232 if (cn_dev) {
233 console_rdev = makeudev(cn_dev->si_umajor,
234 (cn_dev->si_uminor == 255 ?
235 0 : cn_dev->si_uminor));
236 } else {
237 console_rdev = 0;
238 }
239 console_pausing = 0;
240 }
241
242 static void
cnuninit(void)243 cnuninit(void)
244 {
245 if (cn_tab == NULL)
246 return;
247 if (cn_fwd_ops)
248 dev_ops_restore(cn_tab->cn_dev, cn_fwd_ops);
249 cn_fwd_ops = NULL;
250 cn_dev = NULL;
251 }
252
253
254 /*
255 * User has changed the state of the console muting.
256 * This may require us to open or close the device in question.
257 */
258 static int
sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)259 sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
260 {
261 int error;
262 int ocn_mute;
263
264 ocn_mute = cn_mute;
265 error = sysctl_handle_int(oidp, &cn_mute, 0, req);
266 if((error == 0) && (cn_tab != NULL) && (req->newptr != NULL)) {
267 if(ocn_mute && !cn_mute) {
268 /*
269 * going from muted to unmuted.. open the physical dev
270 * if the console has been openned
271 */
272 cninit_finish();
273 if (cn_is_open) {
274 /* XXX curproc is not what we want really */
275 error = dev_dopen(cn_dev, openflag, openmode,
276 curproc->p_ucred, NULL, NULL);
277 }
278 /* if it failed, back it out */
279 if ( error != 0) cnuninit();
280 } else if (!ocn_mute && cn_mute) {
281 /*
282 * going from unmuted to muted.. close the physical dev
283 * if it's only open via /dev/console
284 */
285 if (cn_is_open) {
286 error = dev_dclose(cn_dev, openflag,
287 openmode, NULL);
288 }
289 if (error == 0)
290 cnuninit();
291 }
292 if (error != 0) {
293 /*
294 * back out the change if there was an error
295 */
296 cn_mute = ocn_mute;
297 }
298 }
299 return (error);
300 }
301
302 SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
303 0, sizeof cn_mute, sysctl_kern_consmute, "I", "");
304
305
306 /*
307 * We intercept the OPEN and CLOSE calls on the original device, and
308 * forward the rest through.
309 */
310 static int
cnintercept(struct dev_generic_args * ap)311 cnintercept(struct dev_generic_args *ap)
312 {
313 int error;
314
315 if (ap->a_desc == &dev_open_desc) {
316 error = cnopen((struct dev_open_args *)ap);
317 } else if (ap->a_desc == &dev_close_desc) {
318 error = cnclose((struct dev_close_args *)ap);
319 } else if (cn_fwd_ops) {
320 error = dev_doperate_ops(cn_fwd_ops, ap);
321 } else {
322 error = ENXIO;
323 }
324 return (error);
325 }
326
327 /*
328 * cnopen() is called as an intercept function (dev will be that of the
329 * actual physical device representing our console), and also called from
330 * the muting code and from the /dev/console switch (dev will have the
331 * console's cdevsw).
332 */
333 static int
cnopen(struct dev_open_args * ap)334 cnopen(struct dev_open_args *ap)
335 {
336 cdev_t dev = ap->a_head.a_dev;
337 int flag = ap->a_oflags;
338 int mode = ap->a_devtype;
339 cdev_t cndev;
340 cdev_t physdev;
341 int retval = 0;
342
343 /*
344 * Disallow access to disk volumes if RESTRICTEDROOT
345 */
346 if (caps_priv_check_self(SYSCAP_RESTRICTEDROOT))
347 return (EPERM);
348
349 if (cn_tab == NULL || cn_fwd_ops == NULL)
350 return (0);
351
352 cndev = cn_tab->cn_dev; /* actual physical device */
353 physdev = (dev == cn_devfsdev) ? cndev : dev;
354
355 /*
356 * If mute is active, then non console opens don't get here
357 * so we don't need to check for that. They bypass this and go
358 * straight to the device.
359 *
360 * It is important to note that due to our intercept and the fact
361 * that we might be called via the original (intercepted) device,
362 * the original device's ops may point to us, so to avoid an
363 * infinite recursion we have to forward through cn_fwd_ops.
364 * This is a severe hack that really needs to be fixed XXX.
365 *
366 * XXX at the moment we assume that the port forwarding function
367 * is synchronous for open.
368 */
369 if (!cn_mute) {
370 ap->a_head.a_dev = physdev;
371 retval = dev_doperate_ops(cn_fwd_ops, &ap->a_head);
372 }
373 if (retval == 0) {
374 /*
375 * check if we openned it via /dev/console or
376 * via the physical entry (e.g. /dev/sio0).
377 */
378 if (dev == cndev) {
379 cn_phys_is_open = 1;
380 } else if (physdev == cndev) {
381 openmode = mode;
382 openflag = flag;
383 cn_is_open = 1;
384 }
385 dev->si_tty = cndev->si_tty;
386 }
387 return (retval);
388 }
389
390 /*
391 * cnclose() is called as a port intercept function (dev will be that of the
392 * actual physical device representing our console), and also called from
393 * the muting code and from the /dev/console switch (dev will have the
394 * console's cdevsw).
395 */
396 static int
cnclose(struct dev_close_args * ap)397 cnclose(struct dev_close_args *ap)
398 {
399 struct tty *cn_tp;
400 cdev_t cndev;
401 cdev_t physdev;
402 cdev_t dev = ap->a_head.a_dev;
403
404 if (cn_tab == NULL || cn_fwd_ops == NULL)
405 return(0);
406 cndev = cn_tab->cn_dev;
407 cn_tp = cndev->si_tty;
408 physdev = (dev == cn_devfsdev) ? cndev : dev;
409
410 /*
411 * act appropriatly depending on whether it's /dev/console
412 * or the pysical device (e.g. /dev/sio) that's being closed.
413 * in either case, don't actually close the device unless
414 * both are closed.
415 */
416 if (dev == cndev) {
417 /* the physical device is about to be closed */
418 cn_phys_is_open = 0;
419 if (cn_is_open) {
420 if (cn_tp) {
421 /* perform a ttyhalfclose() */
422 /* reset session and proc group */
423 ttyclearsession(cn_tp);
424 }
425 return(0);
426 }
427 } else if (physdev == cndev) {
428 /* the logical console is about to be closed */
429 cn_is_open = 0;
430 if (cn_phys_is_open)
431 return(0);
432 dev = cndev;
433 }
434 if (cn_fwd_ops) {
435 ap->a_head.a_dev = dev;
436 return (dev_doperate_ops(cn_fwd_ops, &ap->a_head));
437 }
438 return (0);
439 }
440
441 /*
442 * The following functions are dispatched solely from the /dev/console
443 * device. Their job is primarily to forward the request through.
444 * If the console is not attached to anything then write()'s are sunk
445 * to null and reads return 0 (mostly).
446 */
447 static int
cnread(struct dev_read_args * ap)448 cnread(struct dev_read_args *ap)
449 {
450 if (cn_tab == NULL || cn_fwd_ops == NULL)
451 return (0);
452 ap->a_head.a_dev = cn_tab->cn_dev;
453 return (dev_doperate(&ap->a_head));
454 }
455
456 static int
cnwrite(struct dev_write_args * ap)457 cnwrite(struct dev_write_args *ap)
458 {
459 struct uio *uio = ap->a_uio;
460 cdev_t dev;
461
462 if (cn_tab == NULL || cn_fwd_ops == NULL) {
463 uio->uio_resid = 0; /* dump the data */
464 return (0);
465 }
466 if (constty)
467 dev = constty->t_dev;
468 else
469 dev = cn_tab->cn_dev;
470 log_console(uio);
471 ap->a_head.a_dev = dev;
472 return (dev_doperate(&ap->a_head));
473 }
474
475 static int
cnioctl(struct dev_ioctl_args * ap)476 cnioctl(struct dev_ioctl_args *ap)
477 {
478 int error;
479
480 if (cn_tab == NULL || cn_fwd_ops == NULL)
481 return (0);
482 KKASSERT(curproc != NULL);
483 /*
484 * Superuser can always use this to wrest control of console
485 * output from the "virtual" console.
486 */
487 if (ap->a_cmd == TIOCCONS && constty) {
488 if (ap->a_cred) {
489 error = caps_priv_check(ap->a_cred,
490 SYSCAP_RESTRICTEDROOT);
491 if (error)
492 return (error);
493 }
494 constty = NULL;
495 return (0);
496 }
497 ap->a_head.a_dev = cn_tab->cn_dev;
498 return (dev_doperate(&ap->a_head));
499 }
500
501 static int
cnkqfilter(struct dev_kqfilter_args * ap)502 cnkqfilter(struct dev_kqfilter_args *ap)
503 {
504 if ((cn_tab == NULL) || cn_mute || cn_fwd_ops == NULL)
505 return (1);
506 ap->a_head.a_dev = cn_tab->cn_dev;
507 return (dev_doperate(&ap->a_head));
508 }
509
510 /*
511 * These synchronous functions are primarily used the kernel needs to
512 * access the keyboard (e.g. when running the debugger), or output data
513 * directly to the console.
514 */
515 int
cngetc(void)516 cngetc(void)
517 {
518 int c;
519 if ((cn_tab == NULL) || cn_mute)
520 return (-1);
521 c = (*cn_tab->cn_getc)(cn_tab->cn_private);
522 if (c == '\r') c = '\n'; /* console input is always ICRNL */
523 return (c);
524 }
525
526 int
cncheckc(void)527 cncheckc(void)
528 {
529 if ((cn_tab == NULL) || cn_mute)
530 return (-1);
531 return ((*cn_tab->cn_checkc)(cn_tab->cn_private));
532 }
533
534 void
cnpoll(int on)535 cnpoll(int on)
536 {
537 if ((cn_tab == NULL) || cn_mute)
538 return;
539 if (cn_tab->cn_poll)
540 ((*cn_tab->cn_poll)(cn_tab->cn_private, on));
541 }
542
543 void
cnputc(int c)544 cnputc(int c)
545 {
546 char *cp;
547
548 if ((cn_tab == NULL) || cn_mute)
549 return;
550 if (c) {
551 if (c == '\n')
552 (*cn_tab->cn_putc)(cn_tab->cn_private, '\r');
553 (*cn_tab->cn_putc)(cn_tab->cn_private, c);
554 #ifdef DDB
555 if (console_pausing && !db_active && (c == '\n')) {
556 #else
557 if (console_pausing && (c == '\n')) {
558 #endif
559 for(cp=console_pausestr; *cp != '\0'; cp++)
560 (*cn_tab->cn_putc)(cn_tab->cn_private, *cp);
561 if (cngetc() == '.')
562 console_pausing = 0;
563 (*cn_tab->cn_putc)(cn_tab->cn_private, '\r');
564 for(cp=console_pausestr; *cp != '\0'; cp++)
565 (*cn_tab->cn_putc)(cn_tab->cn_private, ' ');
566 (*cn_tab->cn_putc)(cn_tab->cn_private, '\r');
567 }
568 }
569 }
570
571 void
572 cndbctl(int on)
573 {
574 static int refcount;
575
576 if (cn_tab == NULL)
577 return;
578 if (!on)
579 refcount--;
580 if (refcount == 0 && cn_tab->cn_dbctl != NULL)
581 (*cn_tab->cn_dbctl)(cn_tab->cn_private, on);
582 if (on)
583 refcount++;
584 }
585
586 static void
587 cn_drvinit(void *unused)
588 {
589 cn_devfsdev = make_only_devfs_dev(&cn_ops, 0, UID_ROOT, GID_WHEEL,
590 0600, "console");
591 }
592
593 SYSINIT(cndev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR, cn_drvinit, NULL);
594