kern_cons.c revision 91406 
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. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the University of
21 *	California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 *    may be used to endorse or promote products derived from this software
24 *    without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 *	from: @(#)cons.c	7.2 (Berkeley) 5/9/91
39 * $FreeBSD: head/sys/kern/tty_cons.c 91406 2002-02-27 18:32:23Z jhb $
40 */
41
42#include "opt_ddb.h"
43
44#include <sys/param.h>
45#include <sys/systm.h>
46#include <sys/conf.h>
47#include <sys/cons.h>
48#include <sys/fcntl.h>
49#include <sys/kernel.h>
50#include <sys/malloc.h>
51#include <sys/namei.h>
52#include <sys/proc.h>
53#include <sys/queue.h>
54#include <sys/reboot.h>
55#include <sys/sysctl.h>
56#include <sys/tty.h>
57#include <sys/uio.h>
58#include <sys/vnode.h>
59
60#include <ddb/ddb.h>
61
62#include <machine/cpu.h>
63
64static	d_open_t	cnopen;
65static	d_close_t	cnclose;
66static	d_read_t	cnread;
67static	d_write_t	cnwrite;
68static	d_ioctl_t	cnioctl;
69static	d_poll_t	cnpoll;
70static	d_kqfilter_t	cnkqfilter;
71
72#define	CDEV_MAJOR	0
73static struct cdevsw cn_cdevsw = {
74	/* open */	cnopen,
75	/* close */	cnclose,
76	/* read */	cnread,
77	/* write */	cnwrite,
78	/* ioctl */	cnioctl,
79	/* poll */	cnpoll,
80	/* mmap */	nommap,
81	/* strategy */	nostrategy,
82	/* name */	"console",
83	/* maj */	CDEV_MAJOR,
84	/* dump */	nodump,
85	/* psize */	nopsize,
86	/* flags */	D_TTY | D_KQFILTER,
87	/* kqfilter */	cnkqfilter,
88};
89
90struct cn_device {
91	STAILQ_ENTRY(cn_device) cnd_next;
92	char		cnd_name[16];
93	struct		vnode *cnd_vp;
94	struct		consdev *cnd_cn;
95};
96
97#define CNDEVPATHMAX	32
98#define CNDEVTAB_SIZE	4
99static struct cn_device cn_devtab[CNDEVTAB_SIZE];
100static STAILQ_HEAD(, cn_device) cn_devlist =
101    STAILQ_HEAD_INITIALIZER(cn_devlist);
102
103#define CND_INVALID(cnd, td) 						\
104	(cnd == NULL || cnd->cnd_vp == NULL ||				\
105	    (cnd->cnd_vp->v_type == VBAD && !cn_devopen(cnd, td, 1)))
106
107static udev_t	cn_udev_t;
108SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
109	&cn_udev_t, sizeof cn_udev_t, "T,dev_t", "");
110
111int	cons_unavail = 0;	/* XXX:
112				 * physical console not available for
113				 * input (i.e., it is in graphics mode)
114				 */
115static int cn_mute;
116static int openflag;			/* how /dev/console was opened */
117static int cn_is_open;
118static dev_t cn_devfsdev;		/* represents the device private info */
119static u_char console_pausing;		/* pause after each line during probe */
120static char *console_pausestr=
121"<pause; press any key to proceed to next line or '.' to end pause mode>";
122
123void	cndebug(char *);
124
125CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
126SET_DECLARE(cons_set, struct consdev);
127
128void
129cninit(void)
130{
131	struct consdev *best_cn, *cn, **list;
132
133	/*
134	 * Check if we should mute the console (for security reasons perhaps)
135	 * It can be changes dynamically using sysctl kern.consmute
136	 * once we are up and going.
137	 *
138	 */
139        cn_mute = ((boothowto & (RB_MUTE
140			|RB_SINGLE
141			|RB_VERBOSE
142			|RB_ASKNAME
143			|RB_CONFIG)) == RB_MUTE);
144
145	/*
146	 * Find the first console with the highest priority.
147	 */
148	best_cn = NULL;
149	SET_FOREACH(list, cons_set) {
150		cn = *list;
151		if (cn->cn_probe == NULL)
152			continue;
153		cn->cn_probe(cn);
154		if (cn->cn_pri == CN_DEAD)
155			continue;
156		if (best_cn == NULL || cn->cn_pri > best_cn->cn_pri)
157			best_cn = cn;
158		if (boothowto & RB_MULTIPLE) {
159			/*
160			 * Initialize console, and attach to it.
161			 */
162			cnadd(cn);
163			cn->cn_init(cn);
164		}
165	}
166	if (best_cn == NULL)
167		return;
168	if ((boothowto & RB_MULTIPLE) == 0) {
169		cnadd(best_cn);
170		best_cn->cn_init(best_cn);
171	}
172	if (boothowto & RB_PAUSE)
173		console_pausing = 1;
174	/*
175	 * Make the best console the preferred console.
176	 */
177	cnselect(best_cn);
178}
179
180void
181cninit_finish()
182{
183	console_pausing = 0;
184}
185
186/* add a new physical console to back the virtual console */
187int
188cnadd(struct consdev *cn)
189{
190	struct cn_device *cnd;
191	int i;
192
193	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
194		if (cnd->cnd_cn == cn)
195			return (0);
196	for (i = 0; i < CNDEVTAB_SIZE; i++) {
197		cnd = &cn_devtab[i];
198		if (cnd->cnd_cn == NULL)
199			break;
200	}
201	if (cnd->cnd_cn != NULL)
202		return (ENOMEM);
203	cnd->cnd_cn = cn;
204	STAILQ_INSERT_TAIL(&cn_devlist, cnd, cnd_next);
205	return (0);
206}
207
208void
209cnremove(struct consdev *cn)
210{
211	struct cn_device *cnd;
212
213	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
214		if (cnd->cnd_cn != cn)
215			continue;
216		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
217		if (cnd->cnd_vp != NULL)
218			vn_close(cnd->cnd_vp, openflag, NOCRED, NULL);
219		cnd->cnd_vp = NULL;
220		cnd->cnd_cn = NULL;
221		cnd->cnd_name[0] = '\0';
222#if 0
223		/*
224		 * XXX
225		 * syscons gets really confused if console resources are
226		 * freed after the system has initialized.
227		 */
228		if (cn->cn_term != NULL)
229			cn->cn_term(cn);
230#endif
231		return;
232	}
233}
234
235void
236cnselect(struct consdev *cn)
237{
238	struct cn_device *cnd;
239
240	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
241		if (cnd->cnd_cn != cn)
242			continue;
243		if (cnd == STAILQ_FIRST(&cn_devlist))
244			return;
245		STAILQ_REMOVE(&cn_devlist, cnd, cn_device, cnd_next);
246		STAILQ_INSERT_HEAD(&cn_devlist, cnd, cnd_next);
247		return;
248	}
249}
250
251void
252cndebug(char *str)
253{
254	int i, len;
255
256	len = strlen(str);
257	cnputc('>'); cnputc('>'); cnputc('>'); cnputc(' ');
258	for (i = 0; i < len; i++)
259		cnputc(str[i]);
260	cnputc('\n');
261}
262
263static int
264sysctl_kern_console(SYSCTL_HANDLER_ARGS)
265{
266	struct cn_device *cnd;
267	struct consdev *cp, **list;
268	char *name, *p;
269	int delete, len, error;
270
271	len = 2;
272	SET_FOREACH(list, cons_set) {
273		cp = *list;
274		if (cp->cn_dev != NULL)
275			len += strlen(devtoname(cp->cn_dev)) + 1;
276	}
277	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
278		len += strlen(devtoname(cnd->cnd_cn->cn_dev)) + 1;
279	len = len > CNDEVPATHMAX ? len : CNDEVPATHMAX;
280	MALLOC(name, char *, len, M_TEMP, M_WAITOK | M_ZERO);
281	p = name;
282	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
283		p += sprintf(p, "%s,", devtoname(cnd->cnd_cn->cn_dev));
284	*p++ = '/';
285	SET_FOREACH(list, cons_set) {
286		cp = *list;
287		if (cp->cn_dev != NULL)
288			p += sprintf(p, "%s,", devtoname(cp->cn_dev));
289	}
290	error = sysctl_handle_string(oidp, name, len, req);
291	if (error == 0 && req->newptr != NULL) {
292		p = name;
293		error = ENXIO;
294		delete = 0;
295		if (*p == '-') {
296			delete = 1;
297			p++;
298		}
299		SET_FOREACH(list, cons_set) {
300			cp = *list;
301			if (cp->cn_dev == NULL ||
302			    strcmp(p, devtoname(cp->cn_dev)) != 0)
303				continue;
304			if (delete) {
305				cnremove(cp);
306				error = 0;
307			} else {
308				error = cnadd(cp);
309				if (error == 0)
310					cnselect(cp);
311			}
312			break;
313		}
314	}
315	FREE(name, M_TEMP);
316	return (error);
317}
318
319SYSCTL_PROC(_kern, OID_AUTO, console, CTLTYPE_STRING|CTLFLAG_RW,
320	0, 0, sysctl_kern_console, "A", "Console device control");
321
322/*
323 * User has changed the state of the console muting.
324 * This may require us to open or close the device in question.
325 */
326static int
327sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
328{
329	int error;
330	int ocn_mute;
331
332	ocn_mute = cn_mute;
333	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
334	if (error != 0 || req->newptr == NULL)
335		return (error);
336	if (ocn_mute && !cn_mute && cn_is_open)
337		error = cnopen(NODEV, openflag, 0, curthread);
338	else if (!ocn_mute && cn_mute && cn_is_open) {
339		error = cnclose(NODEV, openflag, 0, curthread);
340		cn_is_open = 1;		/* XXX hack */
341	}
342	return (error);
343}
344
345SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
346	0, sizeof(cn_mute), sysctl_kern_consmute, "I", "");
347
348static int
349cn_devopen(struct cn_device *cnd, struct thread *td, int forceopen)
350{
351	char path[CNDEVPATHMAX];
352	struct nameidata nd;
353	struct vnode *vp;
354	dev_t dev;
355	int error;
356
357	if ((vp = cnd->cnd_vp) != NULL) {
358		if (!forceopen && vp->v_type != VBAD) {
359			dev = vp->v_rdev;
360			return ((*devsw(dev)->d_open)(dev, openflag, 0, td));
361		}
362		cnd->cnd_vp = NULL;
363		vn_close(vp, openflag, td->td_ucred, td);
364	}
365	if (cnd->cnd_name[0] == '\0')
366		strncpy(cnd->cnd_name, devtoname(cnd->cnd_cn->cn_dev),
367		    sizeof(cnd->cnd_name));
368	snprintf(path, sizeof(path), "/dev/%s", cnd->cnd_name);
369	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, path, td);
370	error = vn_open(&nd, &openflag, 0);
371	if (error == 0) {
372		NDFREE(&nd, NDF_ONLY_PNBUF);
373		VOP_UNLOCK(nd.ni_vp, 0, td);
374		if (nd.ni_vp->v_type == VCHR)
375			cnd->cnd_vp = nd.ni_vp;
376		else
377			vn_close(nd.ni_vp, openflag, td->td_ucred, td);
378	}
379	return (cnd->cnd_vp != NULL);
380}
381
382static int
383cnopen(dev_t dev, int flag, int mode, struct thread *td)
384{
385	struct cn_device *cnd;
386
387	openflag = flag | FWRITE;	/* XXX */
388	cn_is_open = 1;			/* console is logically open */
389	if (cn_mute)
390		return (0);
391	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next)
392		cn_devopen(cnd, td, 0);
393	return (0);
394}
395
396static int
397cnclose(dev_t dev, int flag, int mode, struct thread *td)
398{
399	struct cn_device *cnd;
400	struct vnode *vp;
401
402	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
403		if ((vp = cnd->cnd_vp) == NULL)
404			continue;
405		cnd->cnd_vp = NULL;
406		vn_close(vp, openflag, td->td_ucred, td);
407	}
408	cn_is_open = 0;
409	return (0);
410}
411
412static int
413cnread(dev_t dev, struct uio *uio, int flag)
414{
415	struct cn_device *cnd;
416
417	cnd = STAILQ_FIRST(&cn_devlist);
418	if (cn_mute || CND_INVALID(cnd, curthread))
419		return (0);
420	dev = cnd->cnd_vp->v_rdev;
421	return ((*devsw(dev)->d_read)(dev, uio, flag));
422}
423
424static int
425cnwrite(dev_t dev, struct uio *uio, int flag)
426{
427	struct cn_device *cnd;
428
429	cnd = STAILQ_FIRST(&cn_devlist);
430	if (cn_mute || CND_INVALID(cnd, curthread))
431		goto done;
432	if (constty)
433		dev = constty->t_dev;
434	else
435		dev = cnd->cnd_vp->v_rdev;
436	if (dev != NULL) {
437		log_console(uio);
438		return ((*devsw(dev)->d_write)(dev, uio, flag));
439	}
440done:
441	uio->uio_resid = 0; /* dump the data */
442	return (0);
443}
444
445static int
446cnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
447{
448	struct cn_device *cnd;
449	int error;
450
451	cnd = STAILQ_FIRST(&cn_devlist);
452	if (cn_mute || CND_INVALID(cnd, td))
453		return (0);
454	/*
455	 * Superuser can always use this to wrest control of console
456	 * output from the "virtual" console.
457	 */
458	if (cmd == TIOCCONS && constty) {
459		error = suser_td(td);
460		if (error)
461			return (error);
462		constty = NULL;
463		return (0);
464	}
465	dev = cnd->cnd_vp->v_rdev;
466	if (dev != NULL)
467		return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, td));
468	return (0);
469}
470
471/*
472 * XXX
473 * poll/kqfilter do not appear to be correct
474 */
475static int
476cnpoll(dev_t dev, int events, struct thread *td)
477{
478	struct cn_device *cnd;
479
480	cnd = STAILQ_FIRST(&cn_devlist);
481	if (cn_mute || CND_INVALID(cnd, td))
482		return (0);
483	dev = cnd->cnd_vp->v_rdev;
484	if (dev != NULL)
485		return ((*devsw(dev)->d_poll)(dev, events, td));
486	return (0);
487}
488
489static int
490cnkqfilter(dev_t dev, struct knote *kn)
491{
492	struct cn_device *cnd;
493
494	cnd = STAILQ_FIRST(&cn_devlist);
495	if (cn_mute || CND_INVALID(cnd, curthread))
496		return (1);
497	dev = cnd->cnd_vp->v_rdev;
498	if (dev != NULL)
499		return ((*devsw(dev)->d_kqfilter)(dev, kn));
500	return (1);
501}
502
503/*
504 * Low level console routines.
505 */
506int
507cngetc(void)
508{
509	int c;
510
511	if (cn_mute)
512		return (-1);
513	while ((c = cncheckc()) == -1)
514		;
515	if (c == '\r')
516		c = '\n';		/* console input is always ICRNL */
517	return (c);
518}
519
520int
521cncheckc(void)
522{
523	struct cn_device *cnd;
524	struct consdev *cn;
525	int c;
526
527	if (cn_mute)
528		return (-1);
529	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
530		cn = cnd->cnd_cn;
531		c = cn->cn_checkc(cn->cn_dev);
532		if (c != -1) {
533			return (c);
534		}
535	}
536	return (-1);
537}
538
539void
540cnputc(int c)
541{
542	struct cn_device *cnd;
543	struct consdev *cn;
544	char *cp;
545
546	if (cn_mute || c == '\0')
547		return;
548	STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
549		cn = cnd->cnd_cn;
550		if (c == '\n')
551			cn->cn_putc(cn->cn_dev, '\r');
552		cn->cn_putc(cn->cn_dev, c);
553	}
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			cnputc(*cp);
561		if (cngetc() == '.')
562			console_pausing = 0;
563		cnputc('\r');
564		for (cp = console_pausestr; *cp != '\0'; cp++)
565			cnputc(' ');
566		cnputc('\r');
567	}
568}
569
570void
571cndbctl(int on)
572{
573	struct cn_device *cnd;
574	struct consdev *cn;
575	static int refcount;
576
577	if (!on)
578		refcount--;
579	if (refcount == 0)
580		STAILQ_FOREACH(cnd, &cn_devlist, cnd_next) {
581			cn = cnd->cnd_cn;
582			if (cn->cn_dbctl != NULL)
583				cn->cn_dbctl(cn->cn_dev, on);
584		}
585	if (on)
586		refcount++;
587}
588
589static void
590cn_drvinit(void *unused)
591{
592
593	cn_devfsdev = make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
594	    "console");
595}
596
597SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)
598