1/* $NetBSD: cons.c,v 1.75 2015/05/29 16:26:45 macallan Exp $ */
2
3/*
4 * Copyright (c) 1988 University of Utah.
5 * Copyright (c) 1990, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * from: Utah $Hdr: cons.c 1.7 92/01/21$
37 *
38 * @(#)cons.c 8.2 (Berkeley) 1/12/94
39 */
40
41#include <sys/cdefs.h>
42__KERNEL_RCSID(0, "$NetBSD: cons.c,v 1.75 2015/05/29 16:26:45 macallan Exp $");
43
44#include <sys/param.h>
45#include <sys/proc.h>
46#include <sys/systm.h>
47#include <sys/buf.h>
48#include <sys/ioctl.h>
49#include <sys/poll.h>
50#include <sys/tty.h>
51#include <sys/file.h>
52#include <sys/conf.h>
53#include <sys/vnode.h>
54#include <sys/kauth.h>
55#include <sys/mutex.h>
56
57#include <dev/cons.h>
58
59#include "nullcons.h"
60
61dev_type_open(cnopen);
62dev_type_close(cnclose);
63dev_type_read(cnread);
64dev_type_write(cnwrite);
65dev_type_ioctl(cnioctl);
66dev_type_poll(cnpoll);
67dev_type_kqfilter(cnkqfilter);
68
69static bool cn_redirect(dev_t *, int, int *);
70
71const struct cdevsw cons_cdevsw = {
72 .d_open = cnopen,
73 .d_close = cnclose,
74 .d_read = cnread,
75 .d_write = cnwrite,
76 .d_ioctl = cnioctl,
77 .d_stop = nostop,
78 .d_tty = notty,
79 .d_poll = cnpoll,
80 .d_mmap = nommap,
81 .d_kqfilter = cnkqfilter,
82 .d_discard = nodiscard,
83 .d_flag = D_TTY
84};
85
86struct tty *constty = NULL; /* virtual console output device */
87struct consdev *cn_tab; /* physical console device info */
88struct vnode *cn_devvp[2]; /* vnode for underlying device. */
89
90int
91cnopen(dev_t dev, int flag, int mode, struct lwp *l)
92{
93 dev_t cndev;
94 int unit, error;
95
96 unit = minor(dev);
97 if (unit > 1)
98 return ENODEV;
99
100 if (cn_tab == NULL)
101 return (0);
102
103 /*
104 * always open the 'real' console device, so we don't get nailed
105 * later. This follows normal device semantics; they always get
106 * open() calls.
107 */
108 cndev = cn_tab->cn_dev;
109#if NNULLCONS > 0
110 if (cndev == NODEV) {
111 nullconsattach(0);
112 }
113#else /* NNULLCONS > 0 */
114 if (cndev == NODEV) {
115 /*
116 * This is most likely an error in the console attach
117 * code. Panicking looks better than jumping into nowhere
118 * through cdevsw below....
119 */
120 panic("cnopen: no console device");
121 }
122#endif /* NNULLCONS > 0 */
123 if (dev == cndev) {
124 /*
125 * This causes cnopen() to be called recursively, which
126 * is generally a bad thing. It is often caused when
127 * dev == 0 and cn_dev has not been set, but was probably
128 * initialised to 0.
129 */
130 panic("cnopen: cn_tab->cn_dev == dev");
131 }
132 if (cn_devvp[unit] != NULLVP)
133 return 0;
134 if ((error = cdevvp(cndev, &cn_devvp[unit])) != 0)
135 printf("cnopen: unable to get vnode reference\n");
136 error = vn_lock(cn_devvp[unit], LK_EXCLUSIVE | LK_RETRY);
137 if (error == 0) {
138 error = VOP_OPEN(cn_devvp[unit], flag, kauth_cred_get());
139 VOP_UNLOCK(cn_devvp[unit]);
140 }
141 return error;
142}
143
144int
145cnclose(dev_t dev, int flag, int mode, struct lwp *l)
146{
147 struct vnode *vp;
148 int unit, error;
149
150 unit = minor(dev);
151
152 if (cn_tab == NULL)
153 return (0);
154
155 vp = cn_devvp[unit];
156 cn_devvp[unit] = NULL;
157 error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
158 if (error == 0) {
159 error = VOP_CLOSE(vp, flag, kauth_cred_get());
160 VOP_UNLOCK(vp);
161 }
162 return error;
163}
164
165int
166cnread(dev_t dev, struct uio *uio, int flag)
167{
168 int error;
169
170 /*
171 * If we would redirect input, punt. This will keep strange
172 * things from happening to people who are using the real
173 * console. Nothing should be using /dev/console for
174 * input (except a shell in single-user mode, but then,
175 * one wouldn't TIOCCONS then).
176 */
177 if (!cn_redirect(&dev, 1, &error))
178 return error;
179 return cdev_read(dev, uio, flag);
180}
181
182int
183cnwrite(dev_t dev, struct uio *uio, int flag)
184{
185 int error;
186
187 /* Redirect output, if that's appropriate. */
188 if (!cn_redirect(&dev, 0, &error))
189 return error;
190 return cdev_write(dev, uio, flag);
191}
192
193int
194cnioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
195{
196 int error;
197
198 error = 0;
199
200 /*
201 * Superuser can always use this to wrest control of console
202 * output from the "virtual" console.
203 */
204 if (cmd == TIOCCONS && constty != NULL) {
205 error = kauth_authorize_device_tty(l->l_cred,
206 KAUTH_DEVICE_TTY_VIRTUAL, constty);
207 if (!error)
208 constty = NULL;
209 return (error);
210 }
211
212 /*
213 * Redirect the ioctl, if that's appropriate.
214 * Note that strange things can happen, if a program does
215 * ioctls on /dev/console, then the console is redirected
216 * out from under it.
217 */
218 if (!cn_redirect(&dev, 0, &error))
219 return error;
220 return cdev_ioctl(dev, cmd, data, flag, l);
221}
222
223/*ARGSUSED*/
224int
225cnpoll(dev_t dev, int events, struct lwp *l)
226{
227 int error;
228
229 /*
230 * Redirect the poll, if that's appropriate.
231 * I don't want to think of the possible side effects
232 * of console redirection here.
233 */
234 if (!cn_redirect(&dev, 0, &error))
235 return POLLHUP;
236 return cdev_poll(dev, events, l);
237}
238
239/*ARGSUSED*/
240int
241cnkqfilter(dev_t dev, struct knote *kn)
242{
243 int error;
244
245 /*
246 * Redirect the kqfilter, if that's appropriate.
247 * I don't want to think of the possible side effects
248 * of console redirection here.
249 */
250 if (!cn_redirect(&dev, 0, &error))
251 return error;
252 return cdev_kqfilter(dev, kn);
253}
254
255int
256cngetc(void)
257{
258 if (cn_tab == NULL)
259 return (0);
260 int s = splhigh();
261 for (;;) {
262 const int rv = (*cn_tab->cn_getc)(cn_tab->cn_dev);
263 if (rv >= 0) {
264 splx(s);
265 return rv;
266 }
267 docritpollhooks();
268 }
269}
270
271int
272cngetsn(char *cp, int size)
273{
274 char *lp;
275 int c, len;
276
277 cnpollc(1);
278
279 lp = cp;
280 len = 0;
281 for (;;) {
282 c = cngetc();
283 switch (c) {
284 case '\n':
285 case '\r':
286 printf("\n");
287 *lp++ = '\0';
288 cnpollc(0);
289 return (len);
290 case '\b':
291 case '\177':
292 case '#':
293 if (len) {
294 --len;
295 --lp;
296 printf("\b \b");
297 }
298 continue;
299 case '@':
300 case 'u'&037: /* CTRL-u */
301 len = 0;
302 lp = cp;
303 printf("\n");
304 continue;
305 default:
306 if (len + 1 >= size || c < ' ') {
307 printf("\007");
308 continue;
309 }
310 printf("%c", c);
311 ++len;
312 *lp++ = c;
313 }
314 }
315}
316
317void
318cnputc(int c)
319{
320
321 if (cn_tab == NULL)
322 return;
323
324/*
325 * XXX
326 * for some reason this causes ARCS firmware to output an endless stream of
327 * whitespaces with n32 kernels, so use the pre-1.74 code for now until I can
328 * figure out why this happens
329 */
330#ifndef sgimips
331 if (c) {
332 if (c == '\n') {
333 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
334 docritpollhooks();
335 }
336 (*cn_tab->cn_putc)(cn_tab->cn_dev, c);
337 }
338#else
339 if (c) {
340 (*cn_tab->cn_putc)(cn_tab->cn_dev, c);
341 if (c == '\n') {
342 docritpollhooks();
343 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
344 }
345 }
346#endif
347}
348
349void
350cnpollc(int on)
351{
352 static int refcount = 0;
353
354 if (cn_tab == NULL)
355 return;
356 if (!on)
357 --refcount;
358 if (refcount == 0)
359 (*cn_tab->cn_pollc)(cn_tab->cn_dev, on);
360 if (on)
361 ++refcount;
362}
363
364void
365nullcnpollc(dev_t dev, int on)
366{
367
368}
369
370void
371cnbell(u_int pitch, u_int period, u_int volume)
372{
373
374 if (cn_tab == NULL || cn_tab->cn_bell == NULL)
375 return;
376 (*cn_tab->cn_bell)(cn_tab->cn_dev, pitch, period, volume);
377}
378
379void
380cnflush(void)
381{
382 if (cn_tab == NULL || cn_tab->cn_flush == NULL)
383 return;
384 (*cn_tab->cn_flush)(cn_tab->cn_dev);
385}
386
387void
388cnhalt(void)
389{
390 if (cn_tab == NULL || cn_tab->cn_halt == NULL)
391 return;
392 (*cn_tab->cn_halt)(cn_tab->cn_dev);
393}
394
395/*
396 * Redirect output, if that's appropriate. If there's no real console,
397 * return ENXIO.
398 *
399 * Call with tty_mutex held.
400 */
401static bool
402cn_redirect(dev_t *devp, int is_read, int *error)
403{
404 dev_t dev = *devp;
405
406 *error = ENXIO;
407 if (constty != NULL && minor(dev) == 0 &&
408 (cn_tab == NULL || (cn_tab->cn_pri != CN_REMOTE))) {
409 if (is_read) {
410 *error = 0;
411 return false;
412 }
413 dev = constty->t_dev;
414 } else if (cn_tab == NULL)
415 return false;
416 else
417 dev = cn_tab->cn_dev;
418 *devp = dev;
419 return true;
420}
421