kern_cons.c revision 69929 
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 69929 2000-12-12 21:18:13Z obrien $
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/proc.h>
52#include <sys/uio.h>
53
54#include <machine/cpu.h>
55
56static	d_open_t	cnopen;
57static	d_close_t	cnclose;
58static	d_read_t	cnread;
59static	d_write_t	cnwrite;
60static	d_ioctl_t	cnioctl;
61static	d_poll_t	cnpoll;
62
63#define	CDEV_MAJOR	0
64static struct cdevsw cn_cdevsw = {
65	/* open */	cnopen,
66	/* close */	cnclose,
67	/* read */	cnread,
68	/* write */	cnwrite,
69	/* ioctl */	cnioctl,
70	/* poll */	cnpoll,
71	/* mmap */	nommap,
72	/* strategy */	nostrategy,
73	/* name */	"console",
74	/* maj */	CDEV_MAJOR,
75	/* dump */	nodump,
76	/* psize */	nopsize,
77	/* flags */	D_TTY,
78	/* bmaj */	-1
79};
80
81static dev_t	cn_dev_t; 	/* seems to be never really used */
82static udev_t	cn_udev_t;
83SYSCTL_OPAQUE(_machdep, CPU_CONSDEV, consdev, CTLFLAG_RD,
84	&cn_udev_t, sizeof cn_udev_t, "T,dev_t", "");
85
86static int cn_mute;
87
88int	cons_unavail = 0;	/* XXX:
89				 * physical console not available for
90				 * input (i.e., it is in graphics mode)
91				 */
92
93static u_char cn_is_open;		/* nonzero if logical console is open */
94static int openmode, openflag;		/* how /dev/console was openned */
95static dev_t cn_devfsdev;		/* represents the device private info */
96static u_char cn_phys_is_open;		/* nonzero if physical device is open */
97static d_close_t *cn_phys_close;	/* physical device close function */
98static d_open_t *cn_phys_open;		/* physical device open function */
99       struct consdev *cn_tab;		/* physical console device info */
100
101CONS_DRIVER(cons, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
102
103void
104cninit()
105{
106	struct consdev *best_cp, *cp, **list;
107
108	/*
109	 * Find the first console with the highest priority.
110	 */
111	best_cp = NULL;
112	list = (struct consdev **)cons_set.ls_items;
113	while ((cp = *list++) != NULL) {
114		if (cp->cn_probe == NULL)
115			continue;
116		(*cp->cn_probe)(cp);
117		if (cp->cn_pri > CN_DEAD &&
118		    (best_cp == NULL || cp->cn_pri > best_cp->cn_pri))
119			best_cp = cp;
120	}
121
122	/*
123	 * Check if we should mute the console (for security reasons perhaps)
124	 * It can be changes dynamically using sysctl kern.consmute
125	 * once we are up and going.
126	 *
127	 */
128        cn_mute = ((boothowto & (RB_MUTE
129			|RB_SINGLE
130			|RB_VERBOSE
131			|RB_ASKNAME
132			|RB_CONFIG)) == RB_MUTE);
133
134	/*
135	 * If no console, give up.
136	 */
137	if (best_cp == NULL) {
138		if (cn_tab != NULL && cn_tab->cn_term != NULL)
139			(*cn_tab->cn_term)(cn_tab);
140		cn_tab = best_cp;
141		return;
142	}
143
144	/*
145	 * Initialize console, then attach to it.  This ordering allows
146	 * debugging using the previous console, if any.
147	 */
148	(*best_cp->cn_init)(best_cp);
149	if (cn_tab != NULL && cn_tab != best_cp) {
150		/* Turn off the previous console.  */
151		if (cn_tab->cn_term != NULL)
152			(*cn_tab->cn_term)(cn_tab);
153	}
154	cn_tab = best_cp;
155}
156
157void
158cninit_finish()
159{
160	struct cdevsw *cdp;
161
162	if ((cn_tab == NULL) || cn_mute)
163		return;
164
165	/*
166	 * Hook the open and close functions.
167	 */
168	cdp = devsw(cn_tab->cn_dev);
169	if (cdp != NULL) {
170		cn_phys_close = cdp->d_close;
171		cdp->d_close = cnclose;
172		cn_phys_open = cdp->d_open;
173		cdp->d_open = cnopen;
174	}
175	cn_dev_t = cn_tab->cn_dev;
176	cn_udev_t = dev2udev(cn_dev_t);
177}
178
179static void
180cnuninit(void)
181{
182	struct cdevsw *cdp;
183
184	if (cn_tab == NULL)
185		return;
186
187	/*
188	 * Unhook the open and close functions.
189	 */
190	cdp = devsw(cn_tab->cn_dev);
191	if (cdp != NULL) {
192		cdp->d_close = cn_phys_close;
193		cdp->d_open = cn_phys_open;
194	}
195	cn_phys_close = NULL;
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 || cn_phys_open == 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 || cn_phys_open == 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
336	if (cn_tab == NULL || cn_phys_open == NULL)
337		return (0);
338	dev = cn_tab->cn_dev;
339	return ((*devsw(dev)->d_read)(dev, uio, flag));
340}
341
342static int
343cnwrite(dev, uio, flag)
344	dev_t dev;
345	struct uio *uio;
346	int flag;
347{
348
349	if (cn_tab == NULL || cn_phys_open == NULL) {
350		uio->uio_resid = 0; /* dump the data */
351		return (0);
352	}
353	if (constty)
354		dev = constty->t_dev;
355	else
356		dev = cn_tab->cn_dev;
357	return ((*devsw(dev)->d_write)(dev, uio, flag));
358}
359
360static int
361cnioctl(dev, cmd, data, flag, p)
362	dev_t dev;
363	u_long cmd;
364	caddr_t data;
365	int flag;
366	struct proc *p;
367{
368	int error;
369
370	if (cn_tab == NULL || cn_phys_open == NULL)
371		return (0);
372	/*
373	 * Superuser can always use this to wrest control of console
374	 * output from the "virtual" console.
375	 */
376	if (cmd == TIOCCONS && constty) {
377		error = suser(p);
378		if (error)
379			return (error);
380		constty = NULL;
381		return (0);
382	}
383	dev = cn_tab->cn_dev;
384	return ((*devsw(dev)->d_ioctl)(dev, cmd, data, flag, p));
385}
386
387static int
388cnpoll(dev, events, p)
389	dev_t dev;
390	int events;
391	struct proc *p;
392{
393	if ((cn_tab == NULL) || cn_mute)
394		return (1);
395
396	dev = cn_tab->cn_dev;
397
398	return ((*devsw(dev)->d_poll)(dev, events, p));
399}
400
401int
402cngetc()
403{
404	int c;
405	if ((cn_tab == NULL) || cn_mute)
406		return (-1);
407	c = (*cn_tab->cn_getc)(cn_tab->cn_dev);
408	if (c == '\r') c = '\n'; /* console input is always ICRNL */
409	return (c);
410}
411
412int
413cncheckc()
414{
415	if ((cn_tab == NULL) || cn_mute)
416		return (-1);
417	return ((*cn_tab->cn_checkc)(cn_tab->cn_dev));
418}
419
420void
421cnputc(c)
422	register int c;
423{
424	if ((cn_tab == NULL) || cn_mute)
425		return;
426	if (c) {
427		if (c == '\n')
428			(*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
429		(*cn_tab->cn_putc)(cn_tab->cn_dev, c);
430	}
431}
432
433void
434cndbctl(on)
435	int on;
436{
437	static int refcount;
438
439	if (cn_tab == NULL)
440		return;
441	if (!on)
442		refcount--;
443	if (refcount == 0 && cn_tab->cn_dbctl != NULL)
444		(*cn_tab->cn_dbctl)(cn_tab->cn_dev, on);
445	if (on)
446		refcount++;
447}
448
449static void
450cn_drvinit(void *unused)
451{
452
453	cn_devfsdev = make_dev(&cn_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
454	    "console");
455}
456
457SYSINIT(cndev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,cn_drvinit,NULL)
458