xref: /openbsd-src/sys/kern/tty_subr.c (revision 43003dfe3ad45d1698bed8a37f2b0f5b14f20d4f) 
1 /*	$OpenBSD: tty_subr.c,v 1.21 2009/07/19 08:16:06 blambert Exp $	*/
2 /*	$NetBSD: tty_subr.c,v 1.13 1996/02/09 19:00:43 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1993, 1994 Theo de Raadt
6  * All rights reserved.
7  *
8  * Per Lindqvist <pgd@compuram.bbt.se> supplied an almost fully working
9  * set of true clist functions that this is very loosely based on.
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  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/buf.h>
35 #include <sys/ioctl.h>
36 #include <sys/tty.h>
37 #include <sys/malloc.h>
38 
39 /*
40  * If TTY_QUOTE functionality isn't required by a line discipline,
41  * it can free c_cq and set it to NULL. This speeds things up,
42  * and also does not use any extra memory. This is useful for (say)
43  * a SLIP line discipline that wants a 32K ring buffer for data
44  * but doesn't need quoting.
45  */
46 #define QMEM(n)		((((n)-1)/NBBY)+1)
47 
48 void	cinit(void);
49 void	clrbits(u_char *, int, int);
50 
51 /*
52  * Initialize clists.
53  */
54 void
55 cinit(void)
56 {
57 }
58 
59 /*
60  * Initialize a particular clist. Ok, they are really ring buffers,
61  * of the specified length, with/without quoting support.
62  */
63 void
64 clalloc(struct clist *clp, int size, int quot)
65 {
66 
67 	clp->c_cs = malloc(size, M_TTYS, M_WAITOK|M_ZERO);
68 
69 	if (quot)
70 		clp->c_cq = malloc(QMEM(size), M_TTYS, M_WAITOK|M_ZERO);
71 	else
72 		clp->c_cq = NULL;
73 
74 	clp->c_cf = clp->c_cl = NULL;
75 	clp->c_ce = clp->c_cs + size;
76 	clp->c_cn = size;
77 	clp->c_cc = 0;
78 }
79 
80 void
81 clfree(struct clist *clp)
82 {
83 	if (clp->c_cs) {
84 		bzero(clp->c_cs, clp->c_cn);
85 		free(clp->c_cs, M_TTYS);
86 	}
87 	if (clp->c_cq) {
88 		bzero(clp->c_cq, QMEM(clp->c_cn));
89 		free(clp->c_cq, M_TTYS);
90 	}
91 	clp->c_cs = clp->c_cq = NULL;
92 }
93 
94 
95 /*
96  * Get a character from a clist.
97  */
98 int
99 getc(struct clist *clp)
100 {
101 	int c = -1;
102 	int s;
103 
104 	s = spltty();
105 	if (clp->c_cc == 0)
106 		goto out;
107 
108 	c = *clp->c_cf & 0xff;
109 	*clp->c_cf = 0;
110 	if (clp->c_cq) {
111 		if (isset(clp->c_cq, clp->c_cf - clp->c_cs) )
112 			c |= TTY_QUOTE;
113 		clrbit(clp->c_cq, clp->c_cl - clp->c_cs);
114 	}
115 	if (++clp->c_cf == clp->c_ce)
116 		clp->c_cf = clp->c_cs;
117 	if (--clp->c_cc == 0)
118 		clp->c_cf = clp->c_cl = (u_char *)0;
119 out:
120 	splx(s);
121 	return c;
122 }
123 
124 /*
125  * Copy clist to buffer.
126  * Return number of bytes moved.
127  */
128 int
129 q_to_b(struct clist *clp, u_char *cp, int count)
130 {
131 	int cc;
132 	u_char *p = cp;
133 	int s;
134 
135 	s = spltty();
136 	/* optimize this while loop */
137 	while (count > 0 && clp->c_cc > 0) {
138 		cc = clp->c_cl - clp->c_cf;
139 		if (clp->c_cf >= clp->c_cl)
140 			cc = clp->c_ce - clp->c_cf;
141 		if (cc > count)
142 			cc = count;
143 		bcopy(clp->c_cf, p, cc);
144 		bzero(clp->c_cf, cc);
145 		if (clp->c_cq)
146 			clrbits(clp->c_cq, clp->c_cl - clp->c_cs, cc);
147 		count -= cc;
148 		p += cc;
149 		clp->c_cc -= cc;
150 		clp->c_cf += cc;
151 		if (clp->c_cf == clp->c_ce)
152 			clp->c_cf = clp->c_cs;
153 	}
154 	if (clp->c_cc == 0)
155 		clp->c_cf = clp->c_cl = (u_char *)0;
156 	splx(s);
157 	return p - cp;
158 }
159 
160 /*
161  * Return count of contiguous characters in clist.
162  * Stop counting if flag&character is non-null.
163  */
164 int
165 ndqb(struct clist *clp, int flag)
166 {
167 	int count = 0;
168 	int i;
169 	int cc;
170 	int s;
171 
172 	s = spltty();
173 	if ((cc = clp->c_cc) == 0)
174 		goto out;
175 
176 	if (flag == 0) {
177 		count = clp->c_cl - clp->c_cf;
178 		if (count <= 0)
179 			count = clp->c_ce - clp->c_cf;
180 		goto out;
181 	}
182 
183 	i = clp->c_cf - clp->c_cs;
184 	if (flag & TTY_QUOTE) {
185 		while (cc-- > 0 && !(clp->c_cs[i++] & (flag & ~TTY_QUOTE) ||
186 		    isset(clp->c_cq, i))) {
187 			count++;
188 			if (i == clp->c_cn)
189 				break;
190 		}
191 	} else {
192 		while (cc-- > 0 && !(clp->c_cs[i++] & flag)) {
193 			count++;
194 			if (i == clp->c_cn)
195 				break;
196 		}
197 	}
198 out:
199 	splx(s);
200 	return count;
201 }
202 
203 /*
204  * Flush count bytes from clist.
205  */
206 void
207 ndflush(struct clist *clp, int count)
208 {
209 	int cc;
210 	int s;
211 
212 	s = spltty();
213 	if (count == clp->c_cc) {
214 		clp->c_cc = 0;
215 		clp->c_cf = clp->c_cl = (u_char *)0;
216 		goto out;
217 	}
218 	/* optimize this while loop */
219 	while (count > 0 && clp->c_cc > 0) {
220 		cc = clp->c_cl - clp->c_cf;
221 		if (clp->c_cf >= clp->c_cl)
222 			cc = clp->c_ce - clp->c_cf;
223 		if (cc > count)
224 			cc = count;
225 		count -= cc;
226 		clp->c_cc -= cc;
227 		clp->c_cf += cc;
228 		if (clp->c_cf == clp->c_ce)
229 			clp->c_cf = clp->c_cs;
230 	}
231 	if (clp->c_cc == 0)
232 		clp->c_cf = clp->c_cl = (u_char *)0;
233 out:
234 	splx(s);
235 }
236 
237 /*
238  * Put a character into the output queue.
239  */
240 int
241 putc(int c, struct clist *clp)
242 {
243 	int i;
244 	int s;
245 
246 	s = spltty();
247 	if (clp->c_cc == clp->c_cn) {
248 		splx(s);
249 		return -1;
250 	}
251 
252 	if (clp->c_cc == 0) {
253 		if (!clp->c_cs) {
254 #if defined(DIAGNOSTIC) || 1
255 			printf("putc: required clalloc\n");
256 #endif
257 			clalloc(clp, 1024, 1);
258 		}
259 		clp->c_cf = clp->c_cl = clp->c_cs;
260 	}
261 
262 	*clp->c_cl = c & 0xff;
263 	i = clp->c_cl - clp->c_cs;
264 	if (clp->c_cq) {
265 		if (c & TTY_QUOTE)
266 			setbit(clp->c_cq, i);
267 		else
268 			clrbit(clp->c_cq, i);
269 	}
270 	clp->c_cc++;
271 	clp->c_cl++;
272 	if (clp->c_cl == clp->c_ce)
273 		clp->c_cl = clp->c_cs;
274 	splx(s);
275 	return 0;
276 }
277 
278 /*
279  * optimized version of
280  *
281  * for (i = 0; i < len; i++)
282  *	clrbit(cp, off + len);
283  */
284 void
285 clrbits(u_char *cp, int off, int len)
286 {
287 	int sby, sbi, eby, ebi;
288 	int i;
289 	u_char mask;
290 
291 	if (len==1) {
292 		clrbit(cp, off);
293 		return;
294 	}
295 
296 	sby = off / NBBY;
297 	sbi = off % NBBY;
298 	eby = (off+len) / NBBY;
299 	ebi = (off+len) % NBBY;
300 	if (sby == eby) {
301 		mask = ((1 << (ebi - sbi)) - 1) << sbi;
302 		cp[sby] &= ~mask;
303 	} else {
304 		mask = (1<<sbi) - 1;
305 		cp[sby++] &= mask;
306 
307 		mask = (1<<ebi) - 1;
308 		cp[eby] &= ~mask;
309 
310 		for (i = sby; i < eby; i++)
311 			cp[i] = 0x00;
312 	}
313 }
314 
315 /*
316  * Copy buffer to clist.
317  * Return number of bytes not transferred.
318  */
319 int
320 b_to_q(u_char *cp, int count, struct clist *clp)
321 {
322 	int cc;
323 	u_char *p = cp;
324 	int s;
325 
326 	if (count <= 0)
327 		return 0;
328 
329 	s = spltty();
330 	if (clp->c_cc == clp->c_cn)
331 		goto out;
332 
333 	if (clp->c_cc == 0) {
334 		if (!clp->c_cs) {
335 #if defined(DIAGNOSTIC) || 1
336 			printf("b_to_q: required clalloc\n");
337 #endif
338 			clalloc(clp, 1024, 1);
339 		}
340 		clp->c_cf = clp->c_cl = clp->c_cs;
341 	}
342 
343 	/* optimize this while loop */
344 	while (count > 0 && clp->c_cc < clp->c_cn) {
345 		cc = clp->c_ce - clp->c_cl;
346 		if (clp->c_cf > clp->c_cl)
347 			cc = clp->c_cf - clp->c_cl;
348 		if (cc > count)
349 			cc = count;
350 		bcopy(p, clp->c_cl, cc);
351 		if (clp->c_cq)
352 			clrbits(clp->c_cq, clp->c_cl - clp->c_cs, cc);
353 		p += cc;
354 		count -= cc;
355 		clp->c_cc += cc;
356 		clp->c_cl += cc;
357 		if (clp->c_cl == clp->c_ce)
358 			clp->c_cl = clp->c_cs;
359 	}
360 out:
361 	splx(s);
362 	return count;
363 }
364 
365 static int cc;
366 
367 /*
368  * Given a non-NULL pointer into the clist return the pointer
369  * to the next character in the list or return NULL if no more chars.
370  *
371  * Callers must not allow getc's to happen between firstc's and getc's
372  * so that the pointer becomes invalid.  Note that interrupts are NOT
373  * masked.
374  */
375 u_char *
376 nextc(struct clist *clp, u_char *cp, int *c)
377 {
378 
379 	if (clp->c_cf == cp) {
380 		/*
381 		 * First time initialization.
382 		 */
383 		cc = clp->c_cc;
384 	}
385 	if (cc == 0 || cp == NULL)
386 		return NULL;
387 	if (--cc == 0)
388 		return NULL;
389 	if (++cp == clp->c_ce)
390 		cp = clp->c_cs;
391 	*c = *cp & 0xff;
392 	if (clp->c_cq) {
393 		if (isset(clp->c_cq, cp - clp->c_cs))
394 			*c |= TTY_QUOTE;
395 	}
396 	return cp;
397 }
398 
399 /*
400  * Given a non-NULL pointer into the clist return the pointer
401  * to the first character in the list or return NULL if no more chars.
402  *
403  * Callers must not allow getc's to happen between firstc's and getc's
404  * so that the pointer becomes invalid.  Note that interrupts are NOT
405  * masked.
406  *
407  * *c is set to the NEXT character
408  */
409 u_char *
410 firstc(struct clist *clp, int *c)
411 {
412 	u_char *cp;
413 
414 	cc = clp->c_cc;
415 	if (cc == 0)
416 		return NULL;
417 	cp = clp->c_cf;
418 	*c = *cp & 0xff;
419 	if (clp->c_cq) {
420 		if (isset(clp->c_cq, cp - clp->c_cs))
421 			*c |= TTY_QUOTE;
422 	}
423 	return clp->c_cf;
424 }
425 
426 /*
427  * Remove the last character in the clist and return it.
428  */
429 int
430 unputc(struct clist *clp)
431 {
432 	unsigned int c = -1;
433 	int s;
434 
435 	s = spltty();
436 	if (clp->c_cc == 0)
437 		goto out;
438 
439 	if (clp->c_cl == clp->c_cs)
440 		clp->c_cl = clp->c_ce - 1;
441 	else
442 		--clp->c_cl;
443 	clp->c_cc--;
444 
445 	c = *clp->c_cl & 0xff;
446 	if (clp->c_cq) {
447 		if (isset(clp->c_cq, clp->c_cl - clp->c_cs))
448 			c |= TTY_QUOTE;
449 	}
450 	if (clp->c_cc == 0)
451 		clp->c_cf = clp->c_cl = (u_char *)0;
452 out:
453 	splx(s);
454 	return c;
455 }
456 
457 /*
458  * Put the chars in the from queue on the end of the to queue.
459  */
460 void
461 catq(struct clist *from, struct clist *to)
462 {
463 	int c;
464 	int s;
465 
466 	s = spltty();
467 	if (from->c_cc == 0) {	/* nothing to move */
468 		splx(s);
469 		return;
470 	}
471 
472 	/*
473 	 * if `to' queue is empty and the queues are the same max size,
474 	 * it is more efficient to just swap the clist structures.
475 	 */
476 	if (to->c_cc == 0 && from->c_cn == to->c_cn) {
477 		struct clist tmp;
478 
479 		tmp = *from;
480 		*from = *to;
481 		*to = tmp;
482 		splx(s);
483 		return;
484 	}
485 	splx(s);
486 
487 	while ((c = getc(from)) != -1)
488 		putc(c, to);
489 }
490