kern_cons.c revision 49680 
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 *	$Id: tty_cons.c,v 1.72 1999/08/09 11:02:43 phk Exp $
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 struct tty *cn_tp;		/* physical console tty struct */
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_tp = (*cdp->d_devtotty)(cn_tab->cn_dev);
178	cn_dev_t = cn_tab->cn_dev;
179	cn_udev_t = dev2udev(cn_dev_t);
180}
181
182static void
183cnuninit(void)
184{
185	struct cdevsw *cdp;
186
187	if (cn_tab == NULL)
188		return;
189
190	/*
191	 * Unhook the open and close functions.
192	 */
193	cdp = devsw(cn_tab->cn_dev);
194	cdp->d_close = cn_phys_close;
195	cn_phys_close = NULL;
196	cdp->d_open = cn_phys_open;
197	cn_phys_open = NULL;
198	cn_tp = NULL;
199	cn_dev_t = NODEV;
200	cn_udev_t = NOUDEV;
201}
202
203/*
204 * User has changed the state of the console muting.
205 * This may require us to open or close the device in question.
206 */
207static int
208sysctl_kern_consmute SYSCTL_HANDLER_ARGS
209{
210	int error;
211	int ocn_mute;
212
213	ocn_mute = cn_mute;
214	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
215	if((error == 0) && (cn_tab != NULL) && (req->newptr != NULL)) {
216		if(ocn_mute && !cn_mute) {
217			/*
218			 * going from muted to unmuted.. open the physical dev
219			 * if the console has been openned
220			 */
221			cninit_finish();
222			if(cn_is_open)
223				/* XXX curproc is not what we want really */
224				error = cnopen(cn_dev_t, openflag,
225					openmode, curproc);
226			/* if it failed, back it out */
227			if ( error != 0) cnuninit();
228		} else if (!ocn_mute && cn_mute) {
229			/*
230			 * going from unmuted to muted.. close the physical dev
231			 * if it's only open via /dev/console
232			 */
233			if(cn_is_open)
234				error = cnclose(cn_dev_t, openflag,
235					openmode, curproc);
236			if ( error == 0) cnuninit();
237		}
238		if (error != 0) {
239			/*
240	 		 * back out the change if there was an error
241			 */
242			cn_mute = ocn_mute;
243		}
244	}
245	return (error);
246}
247
248SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
249	0, sizeof cn_mute, sysctl_kern_consmute, "I", "");
250
251static int
252cnopen(dev, flag, mode, p)
253	dev_t dev;
254	int flag, mode;
255	struct proc *p;
256{
257	dev_t cndev, physdev;
258	int retval = 0;
259
260	if (cn_tab == NULL)
261		return (0);
262	cndev = cn_tab->cn_dev;
263	physdev = (major(dev) == major(cndev) ? dev : cndev);
264	/*
265	 * If mute is active, then non console opens don't get here
266	 * so we don't need to check for that. They
267	 * bypass this and go straight to the device.
268	 */
269	if(!cn_mute)
270		retval = (*cn_phys_open)(physdev, flag, mode, p);
271	if (retval == 0) {
272		/*
273		 * check if we openned it via /dev/console or
274		 * via the physical entry (e.g. /dev/sio0).
275		 */
276		if (dev == cndev)
277			cn_phys_is_open = 1;
278		else if (physdev == cndev) {
279			openmode = mode;
280			openflag = flag;
281			cn_is_open = 1;
282		}
283	}
284	return (retval);
285}
286
287static int
288cnclose(dev, flag, mode, p)
289	dev_t dev;
290	int flag, mode;
291	struct proc *p;
292{
293	dev_t cndev;
294
295	if (cn_tab == NULL)
296		return (0);
297	cndev = cn_tab->cn_dev;
298	/*
299	 * act appropriatly depending on whether it's /dev/console
300	 * or the pysical device (e.g. /dev/sio) that's being closed.
301	 * in either case, don't actually close the device unless
302	 * both are closed.
303	 */
304	if (dev == cndev) {
305		/* the physical device is about to be closed */
306		cn_phys_is_open = 0;
307		if (cn_is_open) {
308			if (cn_tp) {
309				/* perform a ttyhalfclose() */
310				/* reset session and proc group */
311				cn_tp->t_pgrp = NULL;
312				cn_tp->t_session = NULL;
313			}
314			return (0);
315		}
316	} else if (major(dev) != major(cndev)) {
317		/* the logical console is about to be closed */
318		cn_is_open = 0;
319		if (cn_phys_is_open)
320			return (0);
321		dev = cndev;
322	}
323	if(cn_phys_close)
324		return ((*cn_phys_close)(dev, flag, mode, p));
325	return (0);
326}
327
328static int
329cnread(dev, uio, flag)
330	dev_t dev;
331	struct uio *uio;
332	int flag;
333{
334	if ((cn_tab == NULL) || cn_mute)
335		return (0);
336	dev = cn_tab->cn_dev;
337	return ((*devsw(dev)->d_read)(dev, uio, flag));
338}
339
340static int
341cnwrite(dev, uio, flag)
342	dev_t dev;
343	struct uio *uio;
344	int flag;
345{
346	if ((cn_tab == NULL) || cn_mute) {
347		uio->uio_resid = 0; /* dump the data */
348		return (0);
349	}
350	if (constty)
351		dev = constty->t_dev;
352	else
353		dev = cn_tab->cn_dev;
354	return ((*devsw(dev)->d_write)(dev, uio, flag));
355}
356
357static int
358cnioctl(dev, cmd, data, flag, p)
359	dev_t dev;
360	u_long cmd;
361	caddr_t data;
362	int flag;
363	struct proc *p;
364{
365	int error;
366
367	if ((cn_tab == NULL) || cn_mute)
368		return (0);
369	/*
370	 * Superuser can always use this to wrest control of console
371	 * output from the "virtual" console.
372	 */
373	if (cmd == TIOCCONS && constty) {
374		error = suser(p);
375		if (error)
376			return (error);
377		constty = NULL;
378		return (0);
379	}
380	dev = cn_tab->cn_dev;
381	return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, p));
382}
383
384static int
385cnpoll(dev, events, p)
386	dev_t dev;
387	int events;
388	struct proc *p;
389{
390	if ((cn_tab == NULL) || cn_mute)
391		return (1);
392
393	dev = cn_tab->cn_dev;
394
395	return ((*devsw(dev)->d_poll)(dev, events, p));
396}
397
398int
399cngetc()
400{
401	int c;
402	if ((cn_tab == NULL) || cn_mute)
403		return (-1);
404	c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
405	if (c == '\r') c = '\n'; /* console input is always ICRNL */
406	return (c);
407}
408
409int
410cncheckc()
411{
412	if ((cn_tab == NULL) || cn_mute)
413		return (-1);
414	return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
415}
416
417void
418cnputc(c)
419	register int c;
420{
421	if ((cn_tab == NULL) || cn_mute)
422		return;
423	if (c) {
424		if (c == '\n')
425			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
426		(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
427	}
428}
429
430static void
431cn_drvinit(void *unused)
432{
433
434	cdevsw_add(&cn_cdevsw);
435	make_dev (&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "console");
436}
437
438SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)
439
440
441