kern_cons.c revision 69930 
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 69930 2000-12-12 21:20:48Z mjacob $
40 */
41
42#include <sys/param.h>
43#include <sys/systm.h>
44#include <sys/conf.h>
45#include <sys/cons.h>
46#include <sys/kernel.h>
47#include <sys/proc.h>
48#include <sys/reboot.h>
49#include <sys/sysctl.h>
50#include <sys/tty.h>
51#include <sys/uio.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 dev_t cn_devfsdev;		/* represents the device private info */
95static u_char cn_phys_is_open;		/* nonzero if physical device is open */
96static d_close_t *cn_phys_close;	/* physical device close function */
97static d_open_t *cn_phys_open;		/* physical device open function */
98       struct consdev *cn_tab;		/* physical console device info */
99
100CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
101
102void
103cninit()
104{
105	struct consdev *best_cp, *cp, **list;
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	if (cdp != NULL) {
169		cn_phys_close = cdp->d_close;
170		cdp->d_close = cnclose;
171		cn_phys_open = cdp->d_open;
172		cdp->d_open = cnopen;
173	}
174	cn_dev_t = cn_tab->cn_dev;
175	cn_udev_t = dev2udev(cn_dev_t);
176}
177
178static void
179cnuninit(void)
180{
181	struct cdevsw *cdp;
182
183	if (cn_tab == NULL)
184		return;
185
186	/*
187	 * Unhook the open and close functions.
188	 */
189	cdp = devsw(cn_tab->cn_dev);
190	if (cdp != NULL) {
191		cdp->d_close = cn_phys_close;
192		cdp->d_open = cn_phys_open;
193	}
194	cn_phys_close = NULL;
195	cn_phys_open = NULL;
196	cn_dev_t = NODEV;
197	cn_udev_t = NOUDEV;
198}
199
200/*
201 * User has changed the state of the console muting.
202 * This may require us to open or close the device in question.
203 */
204static int
205sysctl_kern_consmute(SYSCTL_HANDLER_ARGS)
206{
207	int error;
208	int ocn_mute;
209
210	ocn_mute = cn_mute;
211	error = sysctl_handle_int(oidp, &cn_mute, 0, req);
212	if((error == 0) && (cn_tab != NULL) && (req->newptr != NULL)) {
213		if(ocn_mute && !cn_mute) {
214			/*
215			 * going from muted to unmuted.. open the physical dev
216			 * if the console has been openned
217			 */
218			cninit_finish();
219			if(cn_is_open)
220				/* XXX curproc is not what we want really */
221				error = cnopen(cn_dev_t, openflag,
222					openmode, curproc);
223			/* if it failed, back it out */
224			if ( error != 0) cnuninit();
225		} else if (!ocn_mute && cn_mute) {
226			/*
227			 * going from unmuted to muted.. close the physical dev
228			 * if it's only open via /dev/console
229			 */
230			if(cn_is_open)
231				error = cnclose(cn_dev_t, openflag,
232					openmode, curproc);
233			if ( error == 0) cnuninit();
234		}
235		if (error != 0) {
236			/*
237	 		 * back out the change if there was an error
238			 */
239			cn_mute = ocn_mute;
240		}
241	}
242	return (error);
243}
244
245SYSCTL_PROC(_kern, OID_AUTO, consmute, CTLTYPE_INT|CTLFLAG_RW,
246	0, sizeof cn_mute, sysctl_kern_consmute, "I", "");
247
248static int
249cnopen(dev, flag, mode, p)
250	dev_t dev;
251	int flag, mode;
252	struct proc *p;
253{
254	dev_t cndev, physdev;
255	int retval = 0;
256
257	if (cn_tab == NULL || cn_phys_open == NULL)
258		return (0);
259	cndev = cn_tab->cn_dev;
260	physdev = (major(dev) == major(cndev) ? dev : cndev);
261	/*
262	 * If mute is active, then non console opens don't get here
263	 * so we don't need to check for that. They
264	 * bypass this and go straight to the device.
265	 */
266	if(!cn_mute)
267		retval = (*cn_phys_open)(physdev, flag, mode, p);
268	if (retval == 0) {
269		/*
270		 * check if we openned it via /dev/console or
271		 * via the physical entry (e.g. /dev/sio0).
272		 */
273		if (dev == cndev)
274			cn_phys_is_open = 1;
275		else if (physdev == cndev) {
276			openmode = mode;
277			openflag = flag;
278			cn_is_open = 1;
279		}
280		dev->si_tty = physdev->si_tty;
281	}
282	return (retval);
283}
284
285static int
286cnclose(dev, flag, mode, p)
287	dev_t dev;
288	int flag, mode;
289	struct proc *p;
290{
291	dev_t cndev;
292	struct tty *cn_tp;
293
294	if (cn_tab == NULL || cn_phys_open == NULL)
295		return (0);
296	cndev = cn_tab->cn_dev;
297	cn_tp = cndev->si_tty;
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
335	if (cn_tab == NULL || cn_phys_open == NULL)
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
348	if (cn_tab == NULL || cn_phys_open == NULL) {
349		uio->uio_resid = 0; /* dump the data */
350		return (0);
351	}
352	if (constty)
353		dev = constty->t_dev;
354	else
355		dev = cn_tab->cn_dev;
356	return ((*devsw(dev)->d_write)(dev, uio, flag));
357}
358
359static int
360cnioctl(dev, cmd, data, flag, p)
361	dev_t dev;
362	u_long cmd;
363	caddr_t data;
364	int flag;
365	struct proc *p;
366{
367	int error;
368
369	if (cn_tab == NULL || cn_phys_open == NULL)
370		return (0);
371	/*
372	 * Superuser can always use this to wrest control of console
373	 * output from the "virtual" console.
374	 */
375	if (cmd == TIOCCONS && constty) {
376		error = suser(p);
377		if (error)
378			return (error);
379		constty = NULL;
380		return (0);
381	}
382	dev = cn_tab->cn_dev;
383	return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, p));
384}
385
386static int
387cnpoll(dev, events, p)
388	dev_t dev;
389	int events;
390	struct proc *p;
391{
392	if ((cn_tab == NULL) || cn_mute)
393		return (1);
394
395	dev = cn_tab->cn_dev;
396
397	return ((*devsw(dev)->d_poll)(dev, events, p));
398}
399
400int
401cngetc()
402{
403	int c;
404	if ((cn_tab == NULL) || cn_mute)
405		return (-1);
406	c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
407	if (c == '\r') c = '\n'; /* console input is always ICRNL */
408	return (c);
409}
410
411int
412cncheckc()
413{
414	if ((cn_tab == NULL) || cn_mute)
415		return (-1);
416	return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
417}
418
419void
420cnputc(c)
421	register int c;
422{
423	if ((cn_tab == NULL) || cn_mute)
424		return;
425	if (c) {
426		if (c == '\n')
427			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
428		(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
429	}
430}
431
432void
433cndbctl(on)
434	int on;
435{
436	static int refcount;
437
438	if (cn_tab == NULL)
439		return;
440	if (!on)
441		refcount--;
442	if (refcount == 0 && cn_tab->cn_dbctl != NULL)
443		(*cn_tab->cn_dbctl)(cn_tab->cn_dev, on);
444	if (on)
445		refcount++;
446}
447
448static void
449cn_drvinit(void *unused)
450{
451
452	cn_devfsdev = make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
453	    "console");
454}
455
456SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)
457