kern_cons.c revision 51654 
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 51654 1999-09-25 16:21:39Z phk $
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	/* stop */	nostop,
70	/* reset */	noreset,
71	/* devtotty */	nodevtotty,
72	/* poll */	cnpoll,
73	/* mmap */	nommap,
74	/* strategy */	nostrategy,
75	/* name */	"console",
76	/* parms */	noparms,
77	/* maj */	CDEV_MAJOR,
78	/* dump */	nodump,
79	/* psize */	nopsize,
80	/* flags */	D_TTY,
81	/* maxio */	0,
82	/* bmaj */	-1
83};
84
85static dev_t	cn_dev_t; 	/* seems to be never really used */
86static udev_t	cn_udev_t;
87SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
88	&cn_udev_t, sizeof cn_udev_t, "T,dev_t", "");
89
90static int cn_mute;
91
92int	cons_unavail = 0;	/* XXX:
93				 * physical console not available for
94				 * input (i.e., it is in graphics mode)
95				 */
96
97static u_char cn_is_open;		/* nonzero if logical console is open */
98static int openmode, openflag;		/* how /dev/console was openned */
99static u_char cn_phys_is_open;		/* nonzero if physical device is open */
100static d_close_t *cn_phys_close;	/* physical device close function */
101static d_open_t *cn_phys_open;		/* physical device open function */
102struct consdev *cn_tab;			/* physical console device info */
103static dev_t condev_t;			/* represents the device private info */
104
105CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL);
106
107void
108cninit()
109{
110	struct consdev **list, *best_cp, *cp;
111
112	/*
113	 * Find the first console with the highest priority.
114	 */
115	best_cp = NULL;
116	list = (struct consdev **)cons_set.ls_items;
117	while ((cp = *list++) != NULL) {
118		if (cp->cn_probe == NULL)
119			continue;
120		(*cp->cn_probe)(cp);
121		if (cp->cn_pri > CN_DEAD &&
122		    (best_cp == NULL || cp->cn_pri > best_cp->cn_pri))
123			best_cp = cp;
124	}
125
126	/*
127	 * Check if we should mute the console (for security reasons perhaps)
128	 * It can be changes dynamically using sysctl kern.consmute
129	 * once we are up and going.
130	 *
131	 */
132        cn_mute = ((boothowto & (RB_MUTE
133			|RB_SINGLE
134			|RB_VERBOSE
135			|RB_ASKNAME
136			|RB_CONFIG)) == RB_MUTE);
137
138	/*
139	 * If no console, give up.
140	 */
141	if (best_cp == NULL) {
142		if (cn_tab != NULL && cn_tab->cn_term != NULL)
143			(*cn_tab->cn_term)(cn_tab);
144		cn_tab = best_cp;
145		return;
146	}
147
148	/*
149	 * Initialize console, then attach to it.  This ordering allows
150	 * debugging using the previous console, if any.
151	 */
152	(*best_cp->cn_init)(best_cp);
153	if (cn_tab != NULL && cn_tab != best_cp) {
154		/* Turn off the previous console.  */
155		if (cn_tab->cn_term != NULL)
156			(*cn_tab->cn_term)(cn_tab);
157	}
158	cn_tab = best_cp;
159}
160
161void
162cninit_finish()
163{
164	struct cdevsw *cdp;
165
166	if ((cn_tab == NULL) || cn_mute)
167		return;
168
169	/*
170	 * Hook the open and close functions.
171	 */
172	cdp = devsw(cn_tab->cn_dev);
173	cn_phys_close = cdp->d_close;
174	cdp->d_close = cnclose;
175	cn_phys_open = cdp->d_open;
176	cdp->d_open = cnopen;
177	cn_dev_t = cn_tab->cn_dev;
178	cn_udev_t = dev2udev(cn_dev_t);
179}
180
181static void
182cnuninit(void)
183{
184	struct cdevsw *cdp;
185
186	if (cn_tab == NULL)
187		return;
188
189	/*
190	 * Unhook the open and close functions.
191	 */
192	cdp = devsw(cn_tab->cn_dev);
193	cdp->d_close = cn_phys_close;
194	cn_phys_close = NULL;
195	cdp->d_open = cn_phys_open;
196	cn_phys_open = NULL;
197	cn_dev_t = NODEV;
198	cn_udev_t = NOUDEV;
199}
200
201/*
202 * User has changed the state of the console muting.
203 * This may require us to open or close the device in question.
204 */
205static int
206sysctl_kern_consmute SYSCTL_HANDLER_ARGS
207{
208	int error;
209	int ocn_mute;
210
211	ocn_mute = cn_mute;
212	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
213	if((error == 0) && (cn_tab != NULL) && (req->newptr != NULL)) {
214		if(ocn_mute && !cn_mute) {
215			/*
216			 * going from muted to unmuted.. open the physical dev
217			 * if the console has been openned
218			 */
219			cninit_finish();
220			if(cn_is_open)
221				/* XXX curproc is not what we want really */
222				error = cnopen(cn_dev_t, openflag,
223					openmode, curproc);
224			/* if it failed, back it out */
225			if ( error != 0) cnuninit();
226		} else if (!ocn_mute && cn_mute) {
227			/*
228			 * going from unmuted to muted.. close the physical dev
229			 * if it's only open via /dev/console
230			 */
231			if(cn_is_open)
232				error = cnclose(cn_dev_t, openflag,
233					openmode, curproc);
234			if ( error == 0) cnuninit();
235		}
236		if (error != 0) {
237			/*
238	 		 * back out the change if there was an error
239			 */
240			cn_mute = ocn_mute;
241		}
242	}
243	return (error);
244}
245
246SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
247	0, sizeof cn_mute, sysctl_kern_consmute, "I", "");
248
249static int
250cnopen(dev, flag, mode, p)
251	dev_t dev;
252	int flag, mode;
253	struct proc *p;
254{
255	dev_t cndev, physdev;
256	int retval = 0;
257
258	if (cn_tab == NULL)
259		return (0);
260	cndev = cn_tab->cn_dev;
261	physdev = (major(dev) == major(cndev) ? dev : cndev);
262	/*
263	 * If mute is active, then non console opens don't get here
264	 * so we don't need to check for that. They
265	 * bypass this and go straight to the device.
266	 */
267	if(!cn_mute)
268		retval = (*cn_phys_open)(physdev, flag, mode, p);
269	if (retval == 0) {
270		/*
271		 * check if we openned it via /dev/console or
272		 * via the physical entry (e.g. /dev/sio0).
273		 */
274		if (dev == cndev)
275			cn_phys_is_open = 1;
276		else if (physdev == cndev) {
277			openmode = mode;
278			openflag = flag;
279			cn_is_open = 1;
280		}
281		dev->si_tty = physdev->si_tty;
282	}
283	return (retval);
284}
285
286static int
287cnclose(dev, flag, mode, p)
288	dev_t dev;
289	int flag, mode;
290	struct proc *p;
291{
292	dev_t cndev;
293	struct tty *cn_tp;
294
295	if (cn_tab == NULL)
296		return (0);
297	cndev = cn_tab->cn_dev;
298	cn_tp = cndev->si_tty;
299	/*
300	 * act appropriatly depending on whether it's /dev/console
301	 * or the pysical device (e.g. /dev/sio) that's being closed.
302	 * in either case, don't actually close the device unless
303	 * both are closed.
304	 */
305	if (dev == cndev) {
306		/* the physical device is about to be closed */
307		cn_phys_is_open = 0;
308		if (cn_is_open) {
309			if (cn_tp) {
310				/* perform a ttyhalfclose() */
311				/* reset session and proc group */
312				cn_tp->t_pgrp = NULL;
313				cn_tp->t_session = NULL;
314			}
315			return (0);
316		}
317	} else if (major(dev) != major(cndev)) {
318		/* the logical console is about to be closed */
319		cn_is_open = 0;
320		if (cn_phys_is_open)
321			return (0);
322		dev = cndev;
323	}
324	if(cn_phys_close)
325		return ((*cn_phys_close)(dev, flag, mode, p));
326	return (0);
327}
328
329static int
330cnread(dev, uio, flag)
331	dev_t dev;
332	struct uio *uio;
333	int flag;
334{
335	if ((cn_tab == NULL) || cn_mute)
336		return (0);
337	dev = cn_tab->cn_dev;
338	return ((*devsw(dev)->d_read)(dev, uio, flag));
339}
340
341static int
342cnwrite(dev, uio, flag)
343	dev_t dev;
344	struct uio *uio;
345	int flag;
346{
347	if ((cn_tab == NULL) || cn_mute) {
348		uio->uio_resid = 0; /* dump the data */
349		return (0);
350	}
351	if (constty)
352		dev = constty->t_dev;
353	else
354		dev = cn_tab->cn_dev;
355	return ((*devsw(dev)->d_write)(dev, uio, flag));
356}
357
358static int
359cnioctl(dev, cmd, data, flag, p)
360	dev_t dev;
361	u_long cmd;
362	caddr_t data;
363	int flag;
364	struct proc *p;
365{
366	int error;
367
368	if ((cn_tab == NULL) || cn_mute)
369		return (0);
370	/*
371	 * Superuser can always use this to wrest control of console
372	 * output from the "virtual" console.
373	 */
374	if (cmd == TIOCCONS && constty) {
375		error = suser(p);
376		if (error)
377			return (error);
378		constty = NULL;
379		return (0);
380	}
381	dev = cn_tab->cn_dev;
382	return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, p));
383}
384
385static int
386cnpoll(dev, events, p)
387	dev_t dev;
388	int events;
389	struct proc *p;
390{
391	if ((cn_tab == NULL) || cn_mute)
392		return (1);
393
394	dev = cn_tab->cn_dev;
395
396	return ((*devsw(dev)->d_poll)(dev, events, p));
397}
398
399int
400cngetc()
401{
402	int c;
403	if ((cn_tab == NULL) || cn_mute)
404		return (-1);
405	c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
406	if (c == '\r') c = '\n'; /* console input is always ICRNL */
407	return (c);
408}
409
410int
411cncheckc()
412{
413	if ((cn_tab == NULL) || cn_mute)
414		return (-1);
415	return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
416}
417
418void
419cnputc(c)
420	register int c;
421{
422	if ((cn_tab == NULL) || cn_mute)
423		return;
424	if (c) {
425		if (c == '\n')
426			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
427		(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
428	}
429}
430
431static void
432cn_drvinit(void *unused)
433{
434
435	cdevsw_add(&cn_cdevsw);
436	condev_t = make_dev (&cn_cdevsw, 0,
437			UID_ROOT, GID_WHEEL, 0600, "console");
438}
439
440SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)
441
442
443