FreeBSD/Linux Kernel Cross Reference
sys/dev/cons.c
1 /* $NetBSD: cons.c,v 1.52 2003/10/18 21:26:22 cdi Exp $ */
2
3 /*
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * the Systems Programming Group of the University of Utah Computer
9 * Science Department.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * from: Utah $Hdr: cons.c 1.7 92/01/21$
36 *
37 * @(#)cons.c 8.2 (Berkeley) 1/12/94
38 */
39
40 /*
41 * Copyright (c) 1988 University of Utah.
42 *
43 * This code is derived from software contributed to Berkeley by
44 * the Systems Programming Group of the University of Utah Computer
45 * Science Department.
46 *
47 * Redistribution and use in source and binary forms, with or without
48 * modification, are permitted provided that the following conditions
49 * are met:
50 * 1. Redistributions of source code must retain the above copyright
51 * notice, this list of conditions and the following disclaimer.
52 * 2. Redistributions in binary form must reproduce the above copyright
53 * notice, this list of conditions and the following disclaimer in the
54 * documentation and/or other materials provided with the distribution.
55 * 3. All advertising materials mentioning features or use of this software
56 * must display the following acknowledgement:
57 * This product includes software developed by the University of
58 * California, Berkeley and its contributors.
59 * 4. Neither the name of the University nor the names of its contributors
60 * may be used to endorse or promote products derived from this software
61 * without specific prior written permission.
62 *
63 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
64 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
65 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
66 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
67 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
68 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
69 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
70 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
71 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
72 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
73 * SUCH DAMAGE.
74 *
75 * from: Utah $Hdr: cons.c 1.7 92/01/21$
76 *
77 * @(#)cons.c 8.2 (Berkeley) 1/12/94
78 */
79
80 #include <sys/cdefs.h>
81 __KERNEL_RCSID(0, "$NetBSD: cons.c,v 1.52 2003/10/18 21:26:22 cdi Exp $");
82
83 #include <sys/param.h>
84 #include <sys/proc.h>
85 #include <sys/user.h>
86 #include <sys/systm.h>
87 #include <sys/buf.h>
88 #include <sys/ioctl.h>
89 #include <sys/tty.h>
90 #include <sys/file.h>
91 #include <sys/conf.h>
92 #include <sys/vnode.h>
93
94 #include <dev/cons.h>
95
96 dev_type_open(cnopen);
97 dev_type_close(cnclose);
98 dev_type_read(cnread);
99 dev_type_write(cnwrite);
100 dev_type_ioctl(cnioctl);
101 dev_type_poll(cnpoll);
102 dev_type_kqfilter(cnkqfilter);
103
104 static const struct cdevsw *cn_redirect(dev_t *, int, int *);
105
106 const struct cdevsw cons_cdevsw = {
107 cnopen, cnclose, cnread, cnwrite, cnioctl,
108 nostop, notty, cnpoll, nommap, cnkqfilter, D_TTY
109 };
110
111 struct tty *constty = NULL; /* virtual console output device */
112 struct consdev *cn_tab; /* physical console device info */
113 struct vnode *cn_devvp[2]; /* vnode for underlying device. */
114
115 int
116 cnopen(dev_t dev, int flag, int mode, struct proc *p)
117 {
118 const struct cdevsw *cdev;
119 dev_t cndev;
120 int unit;
121
122 unit = minor(dev);
123 if (unit > 1)
124 return ENODEV;
125
126 if (cn_tab == NULL)
127 return (0);
128
129 /*
130 * always open the 'real' console device, so we don't get nailed
131 * later. This follows normal device semantics; they always get
132 * open() calls.
133 */
134 cndev = cn_tab->cn_dev;
135 if (cndev == NODEV) {
136 /*
137 * This is most likely an error in the console attach
138 * code. Panicing looks better than jumping into nowhere
139 * through cdevsw below....
140 */
141 panic("cnopen: no console device");
142 }
143 if (dev == cndev) {
144 /*
145 * This causes cnopen() to be called recursively, which
146 * is generally a bad thing. It is often caused when
147 * dev == 0 and cn_dev has not been set, but was probably
148 * initialised to 0.
149 */
150 panic("cnopen: cn_tab->cn_dev == dev");
151 }
152 cdev = cdevsw_lookup(cndev);
153 if (cdev == NULL)
154 return (ENXIO);
155
156 if (cn_devvp[unit] == NULLVP) {
157 /* try to get a reference on its vnode, but fail silently */
158 cdevvp(cndev, &cn_devvp[unit]);
159 }
160 return ((*cdev->d_open)(cndev, flag, mode, p));
161 }
162
163 int
164 cnclose(dev_t dev, int flag, int mode, struct proc *p)
165 {
166 const struct cdevsw *cdev;
167 struct vnode *vp;
168 int unit;
169
170 unit = minor(dev);
171
172 if (cn_tab == NULL)
173 return (0);
174
175 /*
176 * If the real console isn't otherwise open, close it.
177 * If it's otherwise open, don't close it, because that'll
178 * screw up others who have it open.
179 */
180 dev = cn_tab->cn_dev;
181 cdev = cdevsw_lookup(dev);
182 if (cdev == NULL)
183 return (ENXIO);
184 if (cn_devvp[unit] != NULLVP) {
185 /* release our reference to real dev's vnode */
186 vrele(cn_devvp[unit]);
187 cn_devvp[unit] = NULLVP;
188 }
189 if (vfinddev(dev, VCHR, &vp) && vcount(vp))
190 return (0);
191 return ((*cdev->d_close)(dev, flag, mode, p));
192 }
193
194 int
195 cnread(dev_t dev, struct uio *uio, int flag)
196 {
197 const struct cdevsw *cdev;
198 int error;
199
200 /*
201 * If we would redirect input, punt. This will keep strange
202 * things from happening to people who are using the real
203 * console. Nothing should be using /dev/console for
204 * input (except a shell in single-user mode, but then,
205 * one wouldn't TIOCCONS then).
206 */
207 cdev = cn_redirect(&dev, 1, &error);
208 if (cdev == NULL)
209 return error;
210 return ((*cdev->d_read)(dev, uio, flag));
211 }
212
213 int
214 cnwrite(dev_t dev, struct uio *uio, int flag)
215 {
216 const struct cdevsw *cdev;
217 int error;
218
219 /* Redirect output, if that's appropriate. */
220 cdev = cn_redirect(&dev, 0, &error);
221 if (cdev == NULL)
222 return error;
223
224 return ((*cdev->d_write)(dev, uio, flag));
225 }
226
227 int
228 cnioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
229 {
230 const struct cdevsw *cdev;
231 int error;
232
233 /*
234 * Superuser can always use this to wrest control of console
235 * output from the "virtual" console.
236 */
237 if (cmd == TIOCCONS && constty != NULL) {
238 error = suser(p->p_ucred, (u_short *) NULL);
239 if (error)
240 return (error);
241 constty = NULL;
242 return (0);
243 }
244
245 /*
246 * Redirect the ioctl, if that's appropriate.
247 * Note that strange things can happen, if a program does
248 * ioctls on /dev/console, then the console is redirected
249 * out from under it.
250 */
251 cdev = cn_redirect(&dev, 0, &error);
252 if (cdev == NULL)
253 return error;
254 return ((*cdev->d_ioctl)(dev, cmd, data, flag, p));
255 }
256
257 /*ARGSUSED*/
258 int
259 cnpoll(dev_t dev, int events, struct proc *p)
260 {
261 const struct cdevsw *cdev;
262 int error;
263
264 /*
265 * Redirect the poll, if that's appropriate.
266 * I don't want to think of the possible side effects
267 * of console redirection here.
268 */
269 cdev = cn_redirect(&dev, 0, &error);
270 if (cdev == NULL)
271 return error;
272 return ((*cdev->d_poll)(dev, events, p));
273 }
274
275 /*ARGSUSED*/
276 int
277 cnkqfilter(dev_t dev, struct knote *kn)
278 {
279 const struct cdevsw *cdev;
280 int error;
281
282 /*
283 * Redirect the kqfilter, if that's appropriate.
284 * I don't want to think of the possible side effects
285 * of console redirection here.
286 */
287 cdev = cn_redirect(&dev, 0, &error);
288 if (cdev == NULL)
289 return error;
290 return ((*cdev->d_kqfilter)(dev, kn));
291 }
292
293 int
294 cngetc(void)
295 {
296 if (cn_tab == NULL)
297 return (0);
298 return ((*cn_tab->cn_getc)(cn_tab->cn_dev));
299 }
300
301 int
302 cngetsn(char *cp, int size)
303 {
304 char *lp;
305 int c, len;
306
307 cnpollc(1);
308
309 lp = cp;
310 len = 0;
311 for (;;) {
312 c = cngetc();
313 switch (c) {
314 case '\n':
315 case '\r':
316 printf("\n");
317 *lp++ = '\0';
318 cnpollc(0);
319 return (len);
320 case '\b':
321 case '\177':
322 case '#':
323 if (len) {
324 --len;
325 --lp;
326 printf("\b \b");
327 }
328 continue;
329 case '@':
330 case 'u'&037: /* CTRL-u */
331 len = 0;
332 lp = cp;
333 printf("\n");
334 continue;
335 default:
336 if (len + 1 >= size || c < ' ') {
337 printf("\007");
338 continue;
339 }
340 printf("%c", c);
341 ++len;
342 *lp++ = c;
343 }
344 }
345 }
346
347 void
348 cnputc(int c)
349 {
350
351 if (cn_tab == NULL)
352 return;
353
354 if (c) {
355 (*cn_tab->cn_putc)(cn_tab->cn_dev, c);
356 if (c == '\n')
357 (*cn_tab->cn_putc)(cn_tab->cn_dev, '\r');
358 }
359 }
360
361 void
362 cnpollc(int on)
363 {
364 static int refcount = 0;
365
366 if (cn_tab == NULL)
367 return;
368 if (!on)
369 --refcount;
370 if (refcount == 0)
371 (*cn_tab->cn_pollc)(cn_tab->cn_dev, on);
372 if (on)
373 ++refcount;
374 }
375
376 void
377 nullcnpollc(dev_t dev, int on)
378 {
379
380 }
381
382 void
383 cnbell(u_int pitch, u_int period, u_int volume)
384 {
385
386 if (cn_tab == NULL || cn_tab->cn_bell == NULL)
387 return;
388 (*cn_tab->cn_bell)(cn_tab->cn_dev, pitch, period, volume);
389 }
390
391 void
392 cnflush(void)
393 {
394 if (cn_tab == NULL || cn_tab->cn_flush == NULL)
395 return;
396 (*cn_tab->cn_flush)(cn_tab->cn_dev);
397 }
398
399 void
400 cnhalt(void)
401 {
402 if (cn_tab == NULL || cn_tab->cn_halt == NULL)
403 return;
404 (*cn_tab->cn_halt)(cn_tab->cn_dev);
405 }
406
407 static const struct cdevsw *
408 cn_redirect(dev_t *devp, int is_read, int *error)
409 {
410 dev_t dev = *devp;
411
412 /*
413 * Redirect output, if that's appropriate.
414 * If there's no real console, return ENXIO.
415 */
416 *error = ENXIO;
417 if (constty != NULL && minor(dev) == 0 &&
418 (cn_tab == NULL || (cn_tab->cn_pri != CN_REMOTE ))) {
419 if (is_read) {
420 *error = 0;
421 return NULL;
422 }
423 dev = constty->t_dev;
424 } else if (cn_tab == NULL)
425 return NULL;
426 else
427 dev = cn_tab->cn_dev;
428 *devp = dev;
429 return cdevsw_lookup(dev);
430 }
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