kern_cons.c revision 55823 
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 55823 2000-01-11 14:54:01Z yokota $
40 */
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/conf.h>
45#include <sys/kernel.h>
46#include <sys/reboot.h>
47#include <sys/sysctl.h>
48#include <sys/proc.h>
49#include <sys/tty.h>
50#include <sys/uio.h>
51#include <sys/cons.h>
52
53#include <machine/cpu.h>
54
55static	d_open_t	cnopen;
56static	d_close_t	cnclose;
57static	d_read_t	cnread;
58static	d_write_t	cnwrite;
59static	d_ioctl_t	cnioctl;
60static	d_poll_t	cnpoll;
61
62#define	CDEV_MAJOR	0
63static struct cdevsw cn_cdevsw = {
64	/* open */	cnopen,
65	/* close */	cnclose,
66	/* read */	cnread,
67	/* write */	cnwrite,
68	/* ioctl */	cnioctl,
69	/* poll */	cnpoll,
70	/* mmap */	nommap,
71	/* strategy */	nostrategy,
72	/* name */	"console",
73	/* maj */	CDEV_MAJOR,
74	/* dump */	nodump,
75	/* psize */	nopsize,
76	/* flags */	D_TTY,
77	/* bmaj */	-1
78};
79
80static dev_t	cn_dev_t; 	/* seems to be never really used */
81static udev_t	cn_udev_t;
82SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
83	&cn_udev_t, sizeof cn_udev_t, "T,dev_t", "");
84
85static int cn_mute;
86
87int	cons_unavail = 0;	/* XXX:
88				 * physical console not available for
89				 * input (i.e., it is in graphics mode)
90				 */
91
92static u_char cn_is_open;		/* nonzero if logical console is open */
93static int openmode, openflag;		/* how /dev/console was openned */
94static u_char cn_phys_is_open;		/* nonzero if physical device is open */
95static d_close_t *cn_phys_close;	/* physical device close function */
96static d_open_t *cn_phys_open;		/* physical device open function */
97struct consdev *cn_tab;			/* physical console device info */
98static dev_t condev_t;			/* represents the device private info */
99
100CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
101
102void
103cninit()
104{
105	struct consdev **list, *best_cp, *cp;
106
107	/*
108	 * Find the first console with the highest priority.
109	 */
110	best_cp = NULL;
111	list = (struct consdev **)cons_set.ls_items;
112	while ((cp = *list++) != NULL) {
113		if (cp->cn_probe == NULL)
114			continue;
115		(*cp->cn_probe)(cp);
116		if (cp->cn_pri > CN_DEAD &&
117		    (best_cp == NULL || cp->cn_pri > best_cp->cn_pri))
118			best_cp = cp;
119	}
120
121	/*
122	 * Check if we should mute the console (for security reasons perhaps)
123	 * It can be changes dynamically using sysctl kern.consmute
124	 * once we are up and going.
125	 *
126	 */
127        cn_mute = ((boothowto & (RB_MUTE
128			|RB_SINGLE
129			|RB_VERBOSE
130			|RB_ASKNAME
131			|RB_CONFIG)) == RB_MUTE);
132
133	/*
134	 * If no console, give up.
135	 */
136	if (best_cp == NULL) {
137		if (cn_tab != NULL && cn_tab->cn_term != NULL)
138			(*cn_tab->cn_term)(cn_tab);
139		cn_tab = best_cp;
140		return;
141	}
142
143	/*
144	 * Initialize console, then attach to it.  This ordering allows
145	 * debugging using the previous console, if any.
146	 */
147	(*best_cp->cn_init)(best_cp);
148	if (cn_tab != NULL && cn_tab != best_cp) {
149		/* Turn off the previous console.  */
150		if (cn_tab->cn_term != NULL)
151			(*cn_tab->cn_term)(cn_tab);
152	}
153	cn_tab = best_cp;
154}
155
156void
157cninit_finish()
158{
159	struct cdevsw *cdp;
160
161	if ((cn_tab == NULL) || cn_mute)
162		return;
163
164	/*
165	 * Hook the open and close functions.
166	 */
167	cdp = devsw(cn_tab->cn_dev);
168	cn_phys_close = cdp->d_close;
169	cdp->d_close = cnclose;
170	cn_phys_open = cdp->d_open;
171	cdp->d_open = cnopen;
172	cn_dev_t = cn_tab->cn_dev;
173	cn_udev_t = dev2udev(cn_dev_t);
174}
175
176static void
177cnuninit(void)
178{
179	struct cdevsw *cdp;
180
181	if (cn_tab == NULL)
182		return;
183
184	/*
185	 * Unhook the open and close functions.
186	 */
187	cdp = devsw(cn_tab->cn_dev);
188	cdp->d_close = cn_phys_close;
189	cn_phys_close = NULL;
190	cdp->d_open = cn_phys_open;
191	cn_phys_open = NULL;
192	cn_dev_t = NODEV;
193	cn_udev_t = NOUDEV;
194}
195
196/*
197 * User has changed the state of the console muting.
198 * This may require us to open or close the device in question.
199 */
200static int
201sysctl_kern_consmute SYSCTL_HANDLER_ARGS
202{
203	int error;
204	int ocn_mute;
205
206	ocn_mute = cn_mute;
207	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
208	if((error == 0) && (cn_tab != NULL) && (req->newptr != NULL)) {
209		if(ocn_mute && !cn_mute) {
210			/*
211			 * going from muted to unmuted.. open the physical dev
212			 * if the console has been openned
213			 */
214			cninit_finish();
215			if(cn_is_open)
216				/* XXX curproc is not what we want really */
217				error = cnopen(cn_dev_t, openflag,
218					openmode, curproc);
219			/* if it failed, back it out */
220			if ( error != 0) cnuninit();
221		} else if (!ocn_mute && cn_mute) {
222			/*
223			 * going from unmuted to muted.. close the physical dev
224			 * if it's only open via /dev/console
225			 */
226			if(cn_is_open)
227				error = cnclose(cn_dev_t, openflag,
228					openmode, curproc);
229			if ( error == 0) cnuninit();
230		}
231		if (error != 0) {
232			/*
233	 		 * back out the change if there was an error
234			 */
235			cn_mute = ocn_mute;
236		}
237	}
238	return (error);
239}
240
241SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
242	0, sizeof cn_mute, sysctl_kern_consmute, "I", "");
243
244static int
245cnopen(dev, flag, mode, p)
246	dev_t dev;
247	int flag, mode;
248	struct proc *p;
249{
250	dev_t cndev, physdev;
251	int retval = 0;
252
253	if (cn_tab == NULL)
254		return (0);
255	cndev = cn_tab->cn_dev;
256	physdev = (major(dev) == major(cndev) ? dev : cndev);
257	/*
258	 * If mute is active, then non console opens don't get here
259	 * so we don't need to check for that. They
260	 * bypass this and go straight to the device.
261	 */
262	if(!cn_mute)
263		retval = (*cn_phys_open)(physdev, flag, mode, p);
264	if (retval == 0) {
265		/*
266		 * check if we openned it via /dev/console or
267		 * via the physical entry (e.g. /dev/sio0).
268		 */
269		if (dev == cndev)
270			cn_phys_is_open = 1;
271		else if (physdev == cndev) {
272			openmode = mode;
273			openflag = flag;
274			cn_is_open = 1;
275		}
276		dev->si_tty = physdev->si_tty;
277	}
278	return (retval);
279}
280
281static int
282cnclose(dev, flag, mode, p)
283	dev_t dev;
284	int flag, mode;
285	struct proc *p;
286{
287	dev_t cndev;
288	struct tty *cn_tp;
289
290	if (cn_tab == NULL)
291		return (0);
292	cndev = cn_tab->cn_dev;
293	cn_tp = cndev->si_tty;
294	/*
295	 * act appropriatly depending on whether it's /dev/console
296	 * or the pysical device (e.g. /dev/sio) that's being closed.
297	 * in either case, don't actually close the device unless
298	 * both are closed.
299	 */
300	if (dev == cndev) {
301		/* the physical device is about to be closed */
302		cn_phys_is_open = 0;
303		if (cn_is_open) {
304			if (cn_tp) {
305				/* perform a ttyhalfclose() */
306				/* reset session and proc group */
307				cn_tp->t_pgrp = NULL;
308				cn_tp->t_session = NULL;
309			}
310			return (0);
311		}
312	} else if (major(dev) != major(cndev)) {
313		/* the logical console is about to be closed */
314		cn_is_open = 0;
315		if (cn_phys_is_open)
316			return (0);
317		dev = cndev;
318	}
319	if(cn_phys_close)
320		return ((*cn_phys_close)(dev, flag, mode, p));
321	return (0);
322}
323
324static int
325cnread(dev, uio, flag)
326	dev_t dev;
327	struct uio *uio;
328	int flag;
329{
330	if ((cn_tab == NULL) || cn_mute)
331		return (0);
332	dev = cn_tab->cn_dev;
333	return ((*devsw(dev)->d_read)(dev, uio, flag));
334}
335
336static int
337cnwrite(dev, uio, flag)
338	dev_t dev;
339	struct uio *uio;
340	int flag;
341{
342	if ((cn_tab == NULL) || cn_mute) {
343		uio->uio_resid = 0; /* dump the data */
344		return (0);
345	}
346	if (constty)
347		dev = constty->t_dev;
348	else
349		dev = cn_tab->cn_dev;
350	return ((*devsw(dev)->d_write)(dev, uio, flag));
351}
352
353static int
354cnioctl(dev, cmd, data, flag, p)
355	dev_t dev;
356	u_long cmd;
357	caddr_t data;
358	int flag;
359	struct proc *p;
360{
361	int error;
362
363	if ((cn_tab == NULL) || cn_mute)
364		return (0);
365	/*
366	 * Superuser can always use this to wrest control of console
367	 * output from the "virtual" console.
368	 */
369	if (cmd == TIOCCONS && constty) {
370		error = suser(p);
371		if (error)
372			return (error);
373		constty = NULL;
374		return (0);
375	}
376	dev = cn_tab->cn_dev;
377	return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, p));
378}
379
380static int
381cnpoll(dev, events, p)
382	dev_t dev;
383	int events;
384	struct proc *p;
385{
386	if ((cn_tab == NULL) || cn_mute)
387		return (1);
388
389	dev = cn_tab->cn_dev;
390
391	return ((*devsw(dev)->d_poll)(dev, events, p));
392}
393
394int
395cngetc()
396{
397	int c;
398	if ((cn_tab == NULL) || cn_mute)
399		return (-1);
400	c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
401	if (c == '\r') c = '\n'; /* console input is always ICRNL */
402	return (c);
403}
404
405int
406cncheckc()
407{
408	if ((cn_tab == NULL) || cn_mute)
409		return (-1);
410	return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
411}
412
413void
414cnputc(c)
415	register int c;
416{
417	if ((cn_tab == NULL) || cn_mute)
418		return;
419	if (c) {
420		if (c == '\n')
421			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
422		(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
423	}
424}
425
426void
427cndbctl(on)
428	int on;
429{
430	static int refcount;
431
432	if (cn_tab == NULL)
433		return;
434	if (!on)
435		refcount--;
436	if (refcount == 0 && cn_tab->cn_dbctl != NULL)
437		(*cn_tab->cn_dbctl)(cn_tab->cn_dev, on);
438	if (on)
439		refcount++;
440}
441
442static void
443cn_drvinit(void *unused)
444{
445
446	condev_t = make_dev (&cn_cdevsw, 0,
447			UID_ROOT, GID_WHEEL, 0600, "console");
448}
449
450SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)
451
452
453