xref: /freebsd-14-stable/sys/kern/tty_ttydisc.c (revision ae7357f2e712026685709ddf98ad6f767f00675b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Portions of this software were developed under sponsorship from Snow
8  * B.V., the Netherlands.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #include <sys/param.h>
34 #include <sys/fcntl.h>
35 #include <sys/filio.h>
36 #include <sys/kernel.h>
37 #include <sys/signal.h>
38 #include <sys/sysctl.h>
39 #include <sys/systm.h>
40 #include <sys/tty.h>
41 #include <sys/ttycom.h>
42 #include <sys/ttydefaults.h>
43 #include <sys/uio.h>
44 #include <sys/vnode.h>
45 
46 #include <teken/teken.h>
47 #include <teken/teken_wcwidth.h>
48 
49 /*
50  * Standard TTYDISC `termios' line discipline.
51  */
52 
53 /* Statistics. */
54 static unsigned long tty_nin = 0;
55 SYSCTL_ULONG(_kern, OID_AUTO, tty_nin, CTLFLAG_RD,
56 	&tty_nin, 0, "Total amount of bytes received");
57 static unsigned long tty_nout = 0;
58 SYSCTL_ULONG(_kern, OID_AUTO, tty_nout, CTLFLAG_RD,
59 	&tty_nout, 0, "Total amount of bytes transmitted");
60 
61 /* termios comparison macro's. */
62 #define	CMP_CC(v,c) (tp->t_termios.c_cc[v] != _POSIX_VDISABLE && \
63 			tp->t_termios.c_cc[v] == (c))
64 #define	CMP_FLAG(field,opt) (tp->t_termios.c_ ## field ## flag & (opt))
65 
66 /* Characters that cannot be modified through c_cc. */
67 #define CTAB	'\t'
68 #define CNL	'\n'
69 #define CCR	'\r'
70 
71 /* Character is a control character. */
72 #define CTL_VALID(c)	((c) == 0x7f || (unsigned char)(c) < 0x20)
73 /* Control character should be processed on echo. */
74 #define CTL_ECHO(c,q)	(!(q) && ((c) == CERASE2 || (c) == CTAB || \
75     (c) == CNL || (c) == CCR))
76 /* Control character should be printed using ^X notation. */
77 #define CTL_PRINT(c,q)	((c) == 0x7f || ((unsigned char)(c) < 0x20 && \
78     ((q) || ((c) != CTAB && (c) != CNL))))
79 /* Character is whitespace. */
80 #define CTL_WHITE(c)	((c) == ' ' || (c) == CTAB)
81 /* Character is alphanumeric. */
82 #define CTL_ALNUM(c)	(((c) >= '0' && (c) <= '9') || \
83     ((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
84 /* Character is UTF8-encoded. */
85 #define CTL_UTF8(c) (!!((c) & 0x80))
86 /* Character is a UTF8 continuation byte. */
87 #define CTL_UTF8_CONT(c) (((c) & 0xc0) == 0x80)
88 
89 #define	TTY_STACKBUF	256
90 #define UTF8_STACKBUF 4
91 
92 void
ttydisc_open(struct tty * tp)93 ttydisc_open(struct tty *tp)
94 {
95 	ttydisc_optimize(tp);
96 }
97 
98 void
ttydisc_close(struct tty * tp)99 ttydisc_close(struct tty *tp)
100 {
101 
102 	/* Clean up our flags when leaving the discipline. */
103 	tp->t_flags &= ~(TF_STOPPED|TF_HIWAT|TF_ZOMBIE);
104 	tp->t_termios.c_lflag &= ~FLUSHO;
105 
106 	/*
107 	 * POSIX states that we must drain output and flush input on
108 	 * last close.  Draining has already been done if possible.
109 	 */
110 	tty_flush(tp, FREAD | FWRITE);
111 
112 	if (ttyhook_hashook(tp, close))
113 		ttyhook_close(tp);
114 }
115 
116 /*
117  * Populate our break array; it should likely be at least 4 bytes in size to
118  * allow for \n, VEOF, and VEOL.
119  */
120 static void
ttydisc_read_break(struct tty * tp,char * breakc,size_t breaksz)121 ttydisc_read_break(struct tty *tp, char *breakc, size_t breaksz)
122 {
123 	size_t n = 0;
124 
125 	MPASS(breaksz != 0);
126 
127 	breakc[n++] = CNL;
128 #define BREAK_ADD(c) do { \
129 	MPASS(n < breaksz - 1);	/* NUL terminated */	\
130 	if (tp->t_termios.c_cc[c] != _POSIX_VDISABLE)	\
131 		breakc[n++] = tp->t_termios.c_cc[c];	\
132 } while (0)
133 	/* Determine which characters we should trigger on. */
134 	BREAK_ADD(VEOF);
135 	BREAK_ADD(VEOL);
136 #undef BREAK_ADD
137 
138 	breakc[n] = '\0';
139 }
140 
141 size_t
ttydisc_bytesavail(struct tty * tp)142 ttydisc_bytesavail(struct tty *tp)
143 {
144 	size_t clen;
145 	char breakc[4];
146 	unsigned char lastc = _POSIX_VDISABLE;
147 
148 	clen = ttyinq_bytescanonicalized(&tp->t_inq);
149 	if (!CMP_FLAG(l, ICANON) || clen == 0)
150 		return (clen);
151 
152 	ttydisc_read_break(tp, &breakc[0], sizeof(breakc));
153 	clen = ttyinq_findchar(&tp->t_inq, breakc, clen, &lastc);
154 
155 	/*
156 	 * We might have a partial line canonicalized in the input queue if we,
157 	 * for instance, switched to ICANON after taking some input in raw mode.
158 	 * In this case, read(2) will block because we only have a partial line.
159 	 */
160 	if (lastc == _POSIX_VDISABLE)
161 		return (0);
162 
163 	/* If VEOF was our terminal, it must be discarded (not counted). */
164 	if (CMP_CC(VEOF, lastc))
165 		clen--;
166 
167 	return (clen);
168 }
169 
170 void
ttydisc_canonicalize(struct tty * tp)171 ttydisc_canonicalize(struct tty *tp)
172 {
173 	char breakc[4];
174 
175 	/*
176 	 * If we're in non-canonical mode, it's as easy as just canonicalizing
177 	 * the current partial line.
178 	 */
179 	if (!CMP_FLAG(l, ICANON)) {
180 		ttyinq_canonicalize(&tp->t_inq);
181 		return;
182 	}
183 
184 	/*
185 	 * For canonical mode, we need to rescan the buffer for the last EOL
186 	 * indicator.
187 	 */
188 	ttydisc_read_break(tp, &breakc[0], sizeof(breakc));
189 	ttyinq_canonicalize_break(&tp->t_inq, breakc);
190 }
191 
192 static int
ttydisc_read_canonical(struct tty * tp,struct uio * uio,int ioflag)193 ttydisc_read_canonical(struct tty *tp, struct uio *uio, int ioflag)
194 {
195 	char breakc[4]; /* enough to hold \n, VEOF and VEOL. */
196 	int error;
197 	size_t clen, flen = 0;
198 	unsigned char lastc = _POSIX_VDISABLE;
199 
200 	ttydisc_read_break(tp, &breakc[0], sizeof(breakc));
201 
202 	do {
203 		error = tty_wait_background(tp, curthread, SIGTTIN);
204 		if (error)
205 			return (error);
206 
207 		/*
208 		 * Quite a tricky case: unlike the old TTY
209 		 * implementation, this implementation copies data back
210 		 * to userspace in large chunks. Unfortunately, we can't
211 		 * calculate the line length on beforehand if it crosses
212 		 * ttyinq_block boundaries, because multiple reads could
213 		 * then make this code read beyond the newline.
214 		 *
215 		 * This is why we limit the read to:
216 		 * - The size the user has requested
217 		 * - The blocksize (done in tty_inq.c)
218 		 * - The amount of bytes until the newline
219 		 *
220 		 * This causes the line length to be recalculated after
221 		 * each block has been copied to userspace. This will
222 		 * cause the TTY layer to return data in chunks using
223 		 * the blocksize (except the first and last blocks).
224 		 */
225 		clen = ttyinq_findchar(&tp->t_inq, breakc, uio->uio_resid + 1,
226 		    &lastc);
227 
228 		/* No more data. */
229 		if (clen == 0) {
230 			if (tp->t_flags & TF_ZOMBIE)
231 				return (0);
232 			else if (ioflag & IO_NDELAY)
233 				return (EWOULDBLOCK);
234 
235 			error = tty_wait(tp, &tp->t_inwait);
236 			if (error)
237 				return (error);
238 			continue;
239 		}
240 
241 		/*
242 		 * Don't send the EOF char back to userspace.  Our above call to
243 		 * ttyinq_findchar overreads by 1 character in case we would
244 		 * otherwise be leaving an EOF for the next read().  We'll trim
245 		 * clen back down to uio_resid whether we find our EOF or not.
246 		 */
247 		if (CMP_CC(VEOF, lastc))
248 			flen = 1;
249 
250 		/*
251 		 * Trim clen back down to the buffer size, since we had
252 		 * intentionally over-read.
253 		 */
254 		clen = MIN(uio->uio_resid + flen, clen);
255 		MPASS(flen <= clen);
256 
257 		/* Read and throw away the EOF character. */
258 		error = ttyinq_read_uio(&tp->t_inq, tp, uio, clen, flen);
259 		if (error)
260 			return (error);
261 
262 	} while (uio->uio_resid > 0 && lastc == _POSIX_VDISABLE);
263 
264 	return (0);
265 }
266 
267 static int
ttydisc_read_raw_no_timer(struct tty * tp,struct uio * uio,int ioflag)268 ttydisc_read_raw_no_timer(struct tty *tp, struct uio *uio, int ioflag)
269 {
270 	size_t vmin = tp->t_termios.c_cc[VMIN];
271 	ssize_t oresid = uio->uio_resid;
272 	int error;
273 
274 	MPASS(tp->t_termios.c_cc[VTIME] == 0);
275 
276 	/*
277 	 * This routine implements the easy cases of read()s while in
278 	 * non-canonical mode, namely case B and D, where we don't have
279 	 * any timers at all.
280 	 */
281 
282 	for (;;) {
283 		error = tty_wait_background(tp, curthread, SIGTTIN);
284 		if (error)
285 			return (error);
286 
287 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
288 		    uio->uio_resid, 0);
289 		if (error)
290 			return (error);
291 		if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
292 			return (0);
293 
294 		/* We have to wait for more. */
295 		if (tp->t_flags & TF_ZOMBIE)
296 			return (0);
297 		else if (ioflag & IO_NDELAY)
298 			return (EWOULDBLOCK);
299 
300 		error = tty_wait(tp, &tp->t_inwait);
301 		if (error)
302 			return (error);
303 	}
304 }
305 
306 static int
ttydisc_read_raw_read_timer(struct tty * tp,struct uio * uio,int ioflag,int oresid)307 ttydisc_read_raw_read_timer(struct tty *tp, struct uio *uio, int ioflag,
308     int oresid)
309 {
310 	size_t vmin = MAX(tp->t_termios.c_cc[VMIN], 1);
311 	unsigned int vtime = tp->t_termios.c_cc[VTIME];
312 	struct timeval end, now, left;
313 	int error, hz;
314 
315 	MPASS(tp->t_termios.c_cc[VTIME] != 0);
316 
317 	/* Determine when the read should be expired. */
318 	end.tv_sec = vtime / 10;
319 	end.tv_usec = (vtime % 10) * 100000;
320 	getmicrotime(&now);
321 	timevaladd(&end, &now);
322 
323 	for (;;) {
324 		error = tty_wait_background(tp, curthread, SIGTTIN);
325 		if (error)
326 			return (error);
327 
328 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
329 		    uio->uio_resid, 0);
330 		if (error)
331 			return (error);
332 		if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
333 			return (0);
334 
335 		/* Calculate how long we should wait. */
336 		getmicrotime(&now);
337 		if (timevalcmp(&now, &end, >))
338 			return (0);
339 		left = end;
340 		timevalsub(&left, &now);
341 		hz = tvtohz(&left);
342 
343 		/*
344 		 * We have to wait for more. If the timer expires, we
345 		 * should return a 0-byte read.
346 		 */
347 		if (tp->t_flags & TF_ZOMBIE)
348 			return (0);
349 		else if (ioflag & IO_NDELAY)
350 			return (EWOULDBLOCK);
351 
352 		error = tty_timedwait(tp, &tp->t_inwait, hz);
353 		if (error)
354 			return (error == EWOULDBLOCK ? 0 : error);
355 	}
356 
357 	return (0);
358 }
359 
360 static int
ttydisc_read_raw_interbyte_timer(struct tty * tp,struct uio * uio,int ioflag)361 ttydisc_read_raw_interbyte_timer(struct tty *tp, struct uio *uio, int ioflag)
362 {
363 	size_t vmin = tp->t_termios.c_cc[VMIN];
364 	ssize_t oresid = uio->uio_resid;
365 	int error;
366 
367 	MPASS(tp->t_termios.c_cc[VMIN] != 0);
368 	MPASS(tp->t_termios.c_cc[VTIME] != 0);
369 
370 	/*
371 	 * When using the interbyte timer, the timer should be started
372 	 * after the first byte has been received. We just call into the
373 	 * generic read timer code after we've received the first byte.
374 	 */
375 
376 	for (;;) {
377 		error = tty_wait_background(tp, curthread, SIGTTIN);
378 		if (error)
379 			return (error);
380 
381 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
382 		    uio->uio_resid, 0);
383 		if (error)
384 			return (error);
385 		if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
386 			return (0);
387 
388 		/*
389 		 * Not enough data, but we did receive some, which means
390 		 * we'll now start using the interbyte timer.
391 		 */
392 		if (oresid != uio->uio_resid)
393 			break;
394 
395 		/* We have to wait for more. */
396 		if (tp->t_flags & TF_ZOMBIE)
397 			return (0);
398 		else if (ioflag & IO_NDELAY)
399 			return (EWOULDBLOCK);
400 
401 		error = tty_wait(tp, &tp->t_inwait);
402 		if (error)
403 			return (error);
404 	}
405 
406 	return ttydisc_read_raw_read_timer(tp, uio, ioflag, oresid);
407 }
408 
409 int
ttydisc_read(struct tty * tp,struct uio * uio,int ioflag)410 ttydisc_read(struct tty *tp, struct uio *uio, int ioflag)
411 {
412 	int error;
413 
414 	tty_assert_locked(tp);
415 
416 	if (uio->uio_resid == 0)
417 		return (0);
418 
419 	if (CMP_FLAG(l, ICANON))
420 		error = ttydisc_read_canonical(tp, uio, ioflag);
421 	else if (tp->t_termios.c_cc[VTIME] == 0)
422 		error = ttydisc_read_raw_no_timer(tp, uio, ioflag);
423 	else if (tp->t_termios.c_cc[VMIN] == 0)
424 		error = ttydisc_read_raw_read_timer(tp, uio, ioflag,
425 		    uio->uio_resid);
426 	else
427 		error = ttydisc_read_raw_interbyte_timer(tp, uio, ioflag);
428 
429 	if (ttyinq_bytesleft(&tp->t_inq) >= tp->t_inlow ||
430 	    ttyinq_bytescanonicalized(&tp->t_inq) == 0) {
431 		/* Unset the input watermark when we've got enough space. */
432 		tty_hiwat_in_unblock(tp);
433 	}
434 
435 	return (error);
436 }
437 
438 static __inline unsigned int
ttydisc_findchar(const char * obstart,unsigned int oblen)439 ttydisc_findchar(const char *obstart, unsigned int oblen)
440 {
441 	const char *c = obstart;
442 
443 	while (oblen--) {
444 		if (CTL_VALID(*c))
445 			break;
446 		c++;
447 	}
448 
449 	return (c - obstart);
450 }
451 
452 static int
ttydisc_write_oproc(struct tty * tp,char c)453 ttydisc_write_oproc(struct tty *tp, char c)
454 {
455 	unsigned int scnt, error;
456 
457 	MPASS(CMP_FLAG(o, OPOST));
458 	MPASS(CTL_VALID(c));
459 
460 #define PRINT_NORMAL() ttyoutq_write_nofrag(&tp->t_outq, &c, 1)
461 	switch (c) {
462 	case CEOF:
463 		/* End-of-text dropping. */
464 		if (CMP_FLAG(o, ONOEOT))
465 			return (0);
466 		return PRINT_NORMAL();
467 
468 	case CERASE2:
469 		/* Handle backspace to fix tab expansion. */
470 		if (PRINT_NORMAL() != 0)
471 			return (-1);
472 		if (tp->t_column > 0)
473 			tp->t_column--;
474 		return (0);
475 
476 	case CTAB:
477 		/* Tab expansion. */
478 		scnt = 8 - (tp->t_column & 7);
479 		if (CMP_FLAG(o, TAB3)) {
480 			error = ttyoutq_write_nofrag(&tp->t_outq,
481 			    "        ", scnt);
482 		} else {
483 			error = PRINT_NORMAL();
484 		}
485 		if (error)
486 			return (-1);
487 
488 		tp->t_column += scnt;
489 		MPASS((tp->t_column % 8) == 0);
490 		return (0);
491 
492 	case CNL:
493 		/* Newline conversion. */
494 		if (CMP_FLAG(o, ONLCR)) {
495 			/* Convert \n to \r\n. */
496 			error = ttyoutq_write_nofrag(&tp->t_outq, "\r\n", 2);
497 		} else {
498 			error = PRINT_NORMAL();
499 		}
500 		if (error)
501 			return (-1);
502 
503 		if (CMP_FLAG(o, ONLCR|ONLRET)) {
504 			tp->t_column = tp->t_writepos = 0;
505 			ttyinq_reprintpos_set(&tp->t_inq);
506 		}
507 		return (0);
508 
509 	case CCR:
510 		/* Carriage return to newline conversion. */
511 		if (CMP_FLAG(o, OCRNL))
512 			c = CNL;
513 		/* Omit carriage returns on column 0. */
514 		if (CMP_FLAG(o, ONOCR) && tp->t_column == 0)
515 			return (0);
516 		if (PRINT_NORMAL() != 0)
517 			return (-1);
518 
519 		tp->t_column = tp->t_writepos = 0;
520 		ttyinq_reprintpos_set(&tp->t_inq);
521 		return (0);
522 	}
523 
524 	/*
525 	 * Invisible control character. Print it, but don't
526 	 * increase the column count.
527 	 */
528 	return PRINT_NORMAL();
529 #undef PRINT_NORMAL
530 }
531 
532 /*
533  * Just like the old TTY implementation, we need to copy data in chunks
534  * into a temporary buffer. One of the reasons why we need to do this,
535  * is because output processing (only TAB3 though) may allow the buffer
536  * to grow eight times.
537  */
538 int
ttydisc_write(struct tty * tp,struct uio * uio,int ioflag)539 ttydisc_write(struct tty *tp, struct uio *uio, int ioflag)
540 {
541 	char ob[TTY_STACKBUF];
542 	char *obstart;
543 	int error = 0;
544 	unsigned int oblen = 0;
545 
546 	tty_assert_locked(tp);
547 
548 	if (tp->t_flags & TF_ZOMBIE)
549 		return (EIO);
550 
551 	/*
552 	 * We don't need to check whether the process is the foreground
553 	 * process group or if we have a carrier. This is already done
554 	 * in ttydev_write().
555 	 */
556 
557 	while (uio->uio_resid > 0) {
558 		unsigned int nlen;
559 
560 		MPASS(oblen == 0);
561 
562 		if (CMP_FLAG(l, FLUSHO)) {
563 			uio->uio_offset += uio->uio_resid;
564 			uio->uio_resid = 0;
565 			return (0);
566 		}
567 
568 		/* Step 1: read data. */
569 		obstart = ob;
570 		nlen = MIN(uio->uio_resid, sizeof ob);
571 		tty_unlock(tp);
572 		error = uiomove(ob, nlen, uio);
573 		tty_lock(tp);
574 		if (error != 0)
575 			break;
576 		oblen = nlen;
577 
578 		if (tty_gone(tp)) {
579 			error = ENXIO;
580 			break;
581 		}
582 
583 		MPASS(oblen > 0);
584 
585 		/* Step 2: process data. */
586 		do {
587 			unsigned int plen, wlen;
588 
589 			if (CMP_FLAG(l, FLUSHO)) {
590 				uio->uio_offset += uio->uio_resid;
591 				uio->uio_resid = 0;
592 				return (0);
593 			}
594 
595 			/* Search for special characters for post processing. */
596 			if (CMP_FLAG(o, OPOST)) {
597 				plen = ttydisc_findchar(obstart, oblen);
598 			} else {
599 				plen = oblen;
600 			}
601 
602 			if (plen == 0) {
603 				/*
604 				 * We're going to process a character
605 				 * that needs processing
606 				 */
607 				if (ttydisc_write_oproc(tp, *obstart) == 0) {
608 					obstart++;
609 					oblen--;
610 
611 					tp->t_writepos = tp->t_column;
612 					ttyinq_reprintpos_set(&tp->t_inq);
613 					continue;
614 				}
615 			} else {
616 				/* We're going to write regular data. */
617 				wlen = ttyoutq_write(&tp->t_outq, obstart, plen);
618 				obstart += wlen;
619 				oblen -= wlen;
620 				tp->t_column += wlen;
621 
622 				tp->t_writepos = tp->t_column;
623 				ttyinq_reprintpos_set(&tp->t_inq);
624 
625 				if (wlen == plen)
626 					continue;
627 			}
628 
629 			/* Watermark reached. Try to sleep. */
630 			tp->t_flags |= TF_HIWAT_OUT;
631 
632 			if (ioflag & IO_NDELAY) {
633 				error = EWOULDBLOCK;
634 				goto done;
635 			}
636 
637 			/*
638 			 * The driver may write back the data
639 			 * synchronously. Be sure to check the high
640 			 * water mark before going to sleep.
641 			 */
642 			ttydevsw_outwakeup(tp);
643 			if ((tp->t_flags & TF_HIWAT_OUT) == 0)
644 				continue;
645 
646 			error = tty_wait(tp, &tp->t_outwait);
647 			if (error)
648 				goto done;
649 
650 			if (tp->t_flags & TF_ZOMBIE) {
651 				error = EIO;
652 				goto done;
653 			}
654 		} while (oblen > 0);
655 	}
656 
657 done:
658 	if (!tty_gone(tp))
659 		ttydevsw_outwakeup(tp);
660 
661 	/*
662 	 * Add the amount of bytes that we didn't process back to the
663 	 * uio counters. We need to do this to make sure write() doesn't
664 	 * count the bytes we didn't store in the queue.
665 	 */
666 	uio->uio_resid += oblen;
667 	return (error);
668 }
669 
670 void
ttydisc_optimize(struct tty * tp)671 ttydisc_optimize(struct tty *tp)
672 {
673 	tty_assert_locked(tp);
674 
675 	if (ttyhook_hashook(tp, rint_bypass)) {
676 		tp->t_flags |= TF_BYPASS;
677 	} else if (ttyhook_hashook(tp, rint)) {
678 		tp->t_flags &= ~TF_BYPASS;
679 	} else if (!CMP_FLAG(i, ICRNL|IGNCR|IMAXBEL|INLCR|ISTRIP|IXON) &&
680 	    (!CMP_FLAG(i, BRKINT) || CMP_FLAG(i, IGNBRK)) &&
681 	    (!CMP_FLAG(i, PARMRK) ||
682 		CMP_FLAG(i, IGNPAR|IGNBRK) == (IGNPAR|IGNBRK)) &&
683 	    !CMP_FLAG(l, ECHO|ICANON|IEXTEN|ISIG|PENDIN)) {
684 		tp->t_flags |= TF_BYPASS;
685 	} else {
686 		tp->t_flags &= ~TF_BYPASS;
687 	}
688 }
689 
690 void
ttydisc_modem(struct tty * tp,int open)691 ttydisc_modem(struct tty *tp, int open)
692 {
693 
694 	tty_assert_locked(tp);
695 
696 	if (open)
697 		cv_broadcast(&tp->t_dcdwait);
698 
699 	/*
700 	 * Ignore modem status lines when CLOCAL is turned on, but don't
701 	 * enter the zombie state when the TTY isn't opened, because
702 	 * that would cause the TTY to be in zombie state after being
703 	 * opened.
704 	 */
705 	if (!tty_opened(tp) || CMP_FLAG(c, CLOCAL))
706 		return;
707 
708 	if (open == 0) {
709 		/*
710 		 * Lost carrier.
711 		 */
712 		tp->t_flags |= TF_ZOMBIE;
713 
714 		tty_signal_sessleader(tp, SIGHUP);
715 		tty_flush(tp, FREAD|FWRITE);
716 	} else {
717 		/*
718 		 * Carrier is back again.
719 		 */
720 
721 		/* XXX: what should we do here? */
722 	}
723 }
724 
725 static int
ttydisc_echo_force(struct tty * tp,char c,int quote)726 ttydisc_echo_force(struct tty *tp, char c, int quote)
727 {
728 
729 	if (CMP_FLAG(l, FLUSHO))
730 		return 0;
731 
732 	if (CMP_FLAG(o, OPOST) && CTL_ECHO(c, quote)) {
733 		/*
734 		 * Only perform postprocessing when OPOST is turned on
735 		 * and the character is an unquoted BS/TB/NL/CR.
736 		 */
737 		return ttydisc_write_oproc(tp, c);
738 	} else if (CMP_FLAG(l, ECHOCTL) && CTL_PRINT(c, quote)) {
739 		/*
740 		 * Only use ^X notation when ECHOCTL is turned on and
741 		 * we've got an quoted control character.
742 		 *
743 		 * Print backspaces when echoing an end-of-file.
744 		 */
745 		char ob[4] = "^?\b\b";
746 
747 		/* Print ^X notation. */
748 		if (c != 0x7f)
749 			ob[1] = c + 'A' - 1;
750 
751 		if (!quote && CMP_CC(VEOF, c)) {
752 			return ttyoutq_write_nofrag(&tp->t_outq, ob, 4);
753 		} else {
754 			tp->t_column += 2;
755 			return ttyoutq_write_nofrag(&tp->t_outq, ob, 2);
756 		}
757 	} else {
758 		/* Can just be printed. */
759 		tp->t_column++;
760 		return ttyoutq_write_nofrag(&tp->t_outq, &c, 1);
761 	}
762 }
763 
764 static int
ttydisc_echo(struct tty * tp,char c,int quote)765 ttydisc_echo(struct tty *tp, char c, int quote)
766 {
767 
768 	/*
769 	 * Only echo characters when ECHO is turned on, or ECHONL when
770 	 * the character is an unquoted newline.
771 	 */
772 	if (!CMP_FLAG(l, ECHO) &&
773 	    (!CMP_FLAG(l, ECHONL) || c != CNL || quote))
774 		return (0);
775 
776 	return ttydisc_echo_force(tp, c, quote);
777 }
778 
779 static void
ttydisc_reprint_char(void * d,char c,int quote)780 ttydisc_reprint_char(void *d, char c, int quote)
781 {
782 	struct tty *tp = d;
783 
784 	ttydisc_echo(tp, c, quote);
785 }
786 
787 static void
ttydisc_reprint(struct tty * tp)788 ttydisc_reprint(struct tty *tp)
789 {
790 	cc_t c;
791 
792 	/* Print  ^R\n, followed by the line. */
793 	c = tp->t_termios.c_cc[VREPRINT];
794 	if (c != _POSIX_VDISABLE)
795 		ttydisc_echo(tp, c, 0);
796 	ttydisc_echo(tp, CNL, 0);
797 	ttyinq_reprintpos_reset(&tp->t_inq);
798 
799 	ttyinq_line_iterate_from_linestart(&tp->t_inq, ttydisc_reprint_char, tp);
800 }
801 
802 struct ttydisc_recalc_length {
803 	struct tty *tp;
804 	unsigned int curlen;
805 };
806 
807 static void
ttydisc_recalc_charlength(void * d,char c,int quote)808 ttydisc_recalc_charlength(void *d, char c, int quote)
809 {
810 	struct ttydisc_recalc_length *data = d;
811 	struct tty *tp = data->tp;
812 
813 	if (CTL_PRINT(c, quote)) {
814 		if (CMP_FLAG(l, ECHOCTL))
815 			data->curlen += 2;
816 	} else if (c == CTAB) {
817 		data->curlen += 8 - (data->curlen & 7);
818 	} else {
819 		data->curlen++;
820 	}
821 }
822 
823 static unsigned int
ttydisc_recalc_linelength(struct tty * tp)824 ttydisc_recalc_linelength(struct tty *tp)
825 {
826 	struct ttydisc_recalc_length data = { tp, tp->t_writepos };
827 
828 	ttyinq_line_iterate_from_reprintpos(&tp->t_inq,
829 	    ttydisc_recalc_charlength, &data);
830 	return (data.curlen);
831 }
832 
833 static int
ttydisc_rubchar(struct tty * tp)834 ttydisc_rubchar(struct tty *tp)
835 {
836 	char c;
837 	int quote;
838 	unsigned int prevpos, tablen;
839 
840 	if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
841 		return (-1);
842 	ttyinq_unputchar(&tp->t_inq);
843 
844 	if (CMP_FLAG(l, ECHO)) {
845 		/*
846 		 * Remove the character from the screen. This is even
847 		 * safe for characters that span multiple characters
848 		 * (tabs, quoted, etc).
849 		 */
850 		if (tp->t_writepos >= tp->t_column) {
851 			/* Retype the sentence. */
852 			ttydisc_reprint(tp);
853 		} else if (CMP_FLAG(l, ECHOE)) {
854 			if (CTL_PRINT(c, quote)) {
855 				/* Remove ^X formatted chars. */
856 				if (CMP_FLAG(l, ECHOCTL)) {
857 					tp->t_column -= 2;
858 					ttyoutq_write_nofrag(&tp->t_outq,
859 					    "\b\b  \b\b", 6);
860 				}
861 			} else if (c == ' ') {
862 				/* Space character needs no rubbing. */
863 				tp->t_column -= 1;
864 				ttyoutq_write_nofrag(&tp->t_outq, "\b", 1);
865 			} else if (c == CTAB) {
866 				/*
867 				 * Making backspace work with tabs is
868 				 * quite hard. Recalculate the length of
869 				 * this character and remove it.
870 				 *
871 				 * Because terminal settings could be
872 				 * changed while the line is being
873 				 * inserted, the calculations don't have
874 				 * to be correct. Make sure we keep the
875 				 * tab length within proper bounds.
876 				 */
877 				prevpos = ttydisc_recalc_linelength(tp);
878 				if (prevpos >= tp->t_column)
879 					tablen = 1;
880 				else
881 					tablen = tp->t_column - prevpos;
882 				if (tablen > 8)
883 					tablen = 8;
884 
885 				tp->t_column = prevpos;
886 				ttyoutq_write_nofrag(&tp->t_outq,
887 				    "\b\b\b\b\b\b\b\b", tablen);
888 				return (0);
889 			} else if ((tp->t_termios.c_iflag & IUTF8) != 0 &&
890 			    CTL_UTF8(c)) {
891 				uint8_t bytes[UTF8_STACKBUF] = { 0 };
892 				int curidx = UTF8_STACKBUF - 1, cwidth = 1,
893 				    nb = 0;
894 				teken_char_t codepoint;
895 
896 				/* Save current byte. */
897 				bytes[curidx] = c;
898 				curidx--;
899 				nb++;
900 				/* Loop back through inq until we hit the
901 				 * leading byte. */
902 				while (CTL_UTF8_CONT(c) && nb < UTF8_STACKBUF) {
903 					/*
904 					 * Check if we've reached the beginning
905 					 * of the line.
906 					 */
907 					if (ttyinq_peekchar(&tp->t_inq, &c,
908 					    &quote) != 0)
909 						break;
910 					ttyinq_unputchar(&tp->t_inq);
911 					bytes[curidx] = c;
912 					curidx--;
913 					nb++;
914 				}
915 				/*
916 				 * Shift array so that the leading
917 				 * byte ends up at idx 0.
918 				 */
919 				if (nb < UTF8_STACKBUF)
920 					memmove(&bytes[0], &bytes[curidx + 1],
921 					    nb * sizeof(uint8_t));
922 				/* Check for malformed UTF8 characters. */
923 				if (nb == UTF8_STACKBUF &&
924 				    CTL_UTF8_CONT(bytes[0])) {
925 					/*
926 					 * Place all bytes back into the inq and
927 					 * delete the last byte only.
928 					 */
929 					ttyinq_write(&tp->t_inq, bytes,
930 					    UTF8_STACKBUF, 0);
931 					ttyinq_unputchar(&tp->t_inq);
932 				} else {
933 					/* Find codepoint and width. */
934 					codepoint =
935 					    teken_utf8_bytes_to_codepoint(bytes,
936 						nb);
937 					if (codepoint ==
938 						TEKEN_UTF8_INVALID_CODEPOINT ||
939 					    (cwidth = teken_wcwidth(
940 						 codepoint)) == -1) {
941 						/*
942 						 * Place all bytes back into the
943 						 * inq and fall back to
944 						 * default behaviour.
945 						 */
946 						cwidth = 1;
947 						ttyinq_write(&tp->t_inq, bytes,
948 						    nb, 0);
949 						ttyinq_unputchar(&tp->t_inq);
950 					}
951 				}
952 				tp->t_column -= cwidth;
953 				/*
954 				 * Delete character by punching
955 				 * 'cwidth' spaces over it.
956 				 */
957 				if (cwidth == 1)
958 					ttyoutq_write_nofrag(&tp->t_outq,
959 					    "\b \b", 3);
960 				else if (cwidth == 2)
961 					ttyoutq_write_nofrag(&tp->t_outq,
962 					    "\b\b  \b\b", 6);
963 			} else {
964 				/*
965 				 * Remove a regular character by
966 				 * punching a space over it.
967 				 */
968 				tp->t_column -= 1;
969 				ttyoutq_write_nofrag(&tp->t_outq, "\b \b", 3);
970 			}
971 		} else {
972 			/* Don't print spaces. */
973 			ttydisc_echo(tp, tp->t_termios.c_cc[VERASE], 0);
974 		}
975 	}
976 
977 	return (0);
978 }
979 
980 static void
ttydisc_rubword(struct tty * tp)981 ttydisc_rubword(struct tty *tp)
982 {
983 	char c;
984 	int quote, alnum;
985 
986 	/* Strip whitespace first. */
987 	for (;;) {
988 		if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
989 			return;
990 		if (!CTL_WHITE(c))
991 			break;
992 		ttydisc_rubchar(tp);
993 	}
994 
995 	/*
996 	 * Record whether the last character from the previous iteration
997 	 * was alphanumeric or not. We need this to implement ALTWERASE.
998 	 */
999 	alnum = CTL_ALNUM(c);
1000 	for (;;) {
1001 		ttydisc_rubchar(tp);
1002 
1003 		if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
1004 			return;
1005 		if (CTL_WHITE(c))
1006 			return;
1007 		if (CMP_FLAG(l, ALTWERASE) && CTL_ALNUM(c) != alnum)
1008 			return;
1009 	}
1010 }
1011 
1012 int
ttydisc_rint(struct tty * tp,char c,int flags)1013 ttydisc_rint(struct tty *tp, char c, int flags)
1014 {
1015 	int signal, quote = 0;
1016 	char ob[3] = { 0xff, 0x00 };
1017 	size_t ol;
1018 
1019 	tty_assert_locked(tp);
1020 
1021 	atomic_add_long(&tty_nin, 1);
1022 
1023 	if (ttyhook_hashook(tp, rint))
1024 		return ttyhook_rint(tp, c, flags);
1025 
1026 	if (tp->t_flags & TF_BYPASS)
1027 		goto processed;
1028 
1029 	if (flags) {
1030 		if (flags & TRE_BREAK) {
1031 			if (CMP_FLAG(i, IGNBRK)) {
1032 				/* Ignore break characters. */
1033 				return (0);
1034 			} else if (CMP_FLAG(i, BRKINT)) {
1035 				/* Generate SIGINT on break. */
1036 				tty_flush(tp, FREAD|FWRITE);
1037 				tty_signal_pgrp(tp, SIGINT);
1038 				return (0);
1039 			} else {
1040 				/* Just print it. */
1041 				goto parmrk;
1042 			}
1043 		} else if (flags & TRE_FRAMING ||
1044 		    (flags & TRE_PARITY && CMP_FLAG(i, INPCK))) {
1045 			if (CMP_FLAG(i, IGNPAR)) {
1046 				/* Ignore bad characters. */
1047 				return (0);
1048 			} else {
1049 				/* Just print it. */
1050 				goto parmrk;
1051 			}
1052 		}
1053 	}
1054 
1055 	/* Allow any character to perform a wakeup. */
1056 	if (CMP_FLAG(i, IXANY)) {
1057 		tp->t_flags &= ~TF_STOPPED;
1058 		tp->t_termios.c_lflag &= ~FLUSHO;
1059 	}
1060 
1061 	/* Remove the top bit. */
1062 	if (CMP_FLAG(i, ISTRIP))
1063 		c &= ~0x80;
1064 
1065 	/* Skip input processing when we want to print it literally. */
1066 	if (tp->t_flags & TF_LITERAL) {
1067 		tp->t_flags &= ~TF_LITERAL;
1068 		quote = 1;
1069 		goto processed;
1070 	}
1071 
1072 	/* Special control characters that are implementation dependent. */
1073 	if (CMP_FLAG(l, IEXTEN)) {
1074 		/* Accept the next character as literal. */
1075 		if (CMP_CC(VLNEXT, c)) {
1076 			if (CMP_FLAG(l, ECHO)) {
1077 				if (CMP_FLAG(l, ECHOE))
1078 					ttyoutq_write_nofrag(&tp->t_outq, "^\b", 2);
1079 				else
1080 					ttydisc_echo(tp, c, 0);
1081 			}
1082 			tp->t_flags |= TF_LITERAL;
1083 			return (0);
1084 		}
1085 		/* Discard processing */
1086 		if (CMP_CC(VDISCARD, c)) {
1087 			if (CMP_FLAG(l, FLUSHO)) {
1088 				tp->t_termios.c_lflag &= ~FLUSHO;
1089 			} else {
1090 				tty_flush(tp, FWRITE);
1091 				ttydisc_echo(tp, c, 0);
1092 				if (tp->t_inq.ti_end > 0)
1093 					ttydisc_reprint(tp);
1094 				tp->t_termios.c_lflag |= FLUSHO;
1095 			}
1096 		}
1097 	}
1098 
1099 	/*
1100 	 * Handle signal processing.
1101 	 */
1102 	if (CMP_FLAG(l, ISIG)) {
1103 		if (CMP_FLAG(l, ICANON|IEXTEN) == (ICANON|IEXTEN)) {
1104 			if (CMP_CC(VSTATUS, c)) {
1105 				tty_signal_pgrp(tp, SIGINFO);
1106 				return (0);
1107 			}
1108 		}
1109 
1110 		/*
1111 		 * When compared to the old implementation, this
1112 		 * implementation also flushes the output queue. POSIX
1113 		 * is really brief about this, but does makes us assume
1114 		 * we have to do so.
1115 		 */
1116 		signal = 0;
1117 		if (CMP_CC(VINTR, c)) {
1118 			signal = SIGINT;
1119 		} else if (CMP_CC(VQUIT, c)) {
1120 			signal = SIGQUIT;
1121 		} else if (CMP_CC(VSUSP, c)) {
1122 			signal = SIGTSTP;
1123 		}
1124 
1125 		if (signal != 0) {
1126 			/*
1127 			 * Echo the character before signalling the
1128 			 * processes.
1129 			 */
1130 			if (!CMP_FLAG(l, NOFLSH))
1131 				tty_flush(tp, FREAD|FWRITE);
1132 			ttydisc_echo(tp, c, 0);
1133 			tty_signal_pgrp(tp, signal);
1134 			return (0);
1135 		}
1136 	}
1137 
1138 	/*
1139 	 * Handle start/stop characters.
1140 	 */
1141 	if (CMP_FLAG(i, IXON)) {
1142 		if (CMP_CC(VSTOP, c)) {
1143 			/* Stop it if we aren't stopped yet. */
1144 			if ((tp->t_flags & TF_STOPPED) == 0) {
1145 				tp->t_flags |= TF_STOPPED;
1146 				return (0);
1147 			}
1148 			/*
1149 			 * Fallthrough:
1150 			 * When VSTART == VSTOP, we should make this key
1151 			 * toggle it.
1152 			 */
1153 			if (!CMP_CC(VSTART, c))
1154 				return (0);
1155 		}
1156 		if (CMP_CC(VSTART, c)) {
1157 			tp->t_flags &= ~TF_STOPPED;
1158 			return (0);
1159 		}
1160 	}
1161 
1162 	/* Conversion of CR and NL. */
1163 	switch (c) {
1164 	case CCR:
1165 		if (CMP_FLAG(i, IGNCR))
1166 			return (0);
1167 		if (CMP_FLAG(i, ICRNL))
1168 			c = CNL;
1169 		break;
1170 	case CNL:
1171 		if (CMP_FLAG(i, INLCR))
1172 			c = CCR;
1173 		break;
1174 	}
1175 
1176 	/* Canonical line editing. */
1177 	if (CMP_FLAG(l, ICANON)) {
1178 		if (CMP_CC(VERASE, c) || CMP_CC(VERASE2, c)) {
1179 			ttydisc_rubchar(tp);
1180 			return (0);
1181 		} else if (CMP_CC(VKILL, c)) {
1182 			while (ttydisc_rubchar(tp) == 0);
1183 			return (0);
1184 		} else if (CMP_FLAG(l, IEXTEN)) {
1185 			if (CMP_CC(VWERASE, c)) {
1186 				ttydisc_rubword(tp);
1187 				return (0);
1188 			} else if (CMP_CC(VREPRINT, c)) {
1189 				ttydisc_reprint(tp);
1190 				return (0);
1191 			}
1192 		}
1193 	}
1194 
1195 processed:
1196 	if (CMP_FLAG(i, PARMRK) && (unsigned char)c == 0xff) {
1197 		/* Print 0xff 0xff. */
1198 		ob[1] = 0xff;
1199 		ol = 2;
1200 		quote = 1;
1201 	} else {
1202 		ob[0] = c;
1203 		ol = 1;
1204 	}
1205 
1206 	goto print;
1207 
1208 parmrk:
1209 	if (CMP_FLAG(i, PARMRK)) {
1210 		/* Prepend 0xff 0x00 0x.. */
1211 		ob[2] = c;
1212 		ol = 3;
1213 		quote = 1;
1214 	} else {
1215 		ob[0] = c;
1216 		ol = 1;
1217 	}
1218 
1219 print:
1220 	/* See if we can store this on the input queue. */
1221 	if (ttyinq_write_nofrag(&tp->t_inq, ob, ol, quote) != 0) {
1222 		if (CMP_FLAG(i, IMAXBEL))
1223 			ttyoutq_write_nofrag(&tp->t_outq, "\a", 1);
1224 
1225 		/*
1226 		 * Prevent a deadlock here. It may be possible that a
1227 		 * user has entered so much data, there is no data
1228 		 * available to read(), but the buffers are full anyway.
1229 		 *
1230 		 * Only enter the high watermark if the device driver
1231 		 * can actually transmit something.
1232 		 */
1233 		if (ttyinq_bytescanonicalized(&tp->t_inq) == 0)
1234 			return (0);
1235 
1236 		tty_hiwat_in_block(tp);
1237 		return (-1);
1238 	}
1239 
1240 	/*
1241 	 * In raw mode, we canonicalize after receiving a single
1242 	 * character. Otherwise, we canonicalize when we receive a
1243 	 * newline, VEOL or VEOF, but only when it isn't quoted.
1244 	 */
1245 	if (!CMP_FLAG(l, ICANON) ||
1246 	    (!quote && (c == CNL || CMP_CC(VEOL, c) || CMP_CC(VEOF, c)))) {
1247 		ttyinq_canonicalize(&tp->t_inq);
1248 	}
1249 
1250 	ttydisc_echo(tp, c, quote);
1251 
1252 	return (0);
1253 }
1254 
1255 size_t
ttydisc_rint_simple(struct tty * tp,const void * buf,size_t len)1256 ttydisc_rint_simple(struct tty *tp, const void *buf, size_t len)
1257 {
1258 	const char *cbuf;
1259 
1260 	if (ttydisc_can_bypass(tp))
1261 		return (ttydisc_rint_bypass(tp, buf, len));
1262 
1263 	for (cbuf = buf; len-- > 0; cbuf++) {
1264 		if (ttydisc_rint(tp, *cbuf, 0) != 0)
1265 			break;
1266 	}
1267 
1268 	return (cbuf - (const char *)buf);
1269 }
1270 
1271 size_t
ttydisc_rint_bypass(struct tty * tp,const void * buf,size_t len)1272 ttydisc_rint_bypass(struct tty *tp, const void *buf, size_t len)
1273 {
1274 	size_t ret;
1275 
1276 	tty_assert_locked(tp);
1277 
1278 	MPASS(tp->t_flags & TF_BYPASS);
1279 
1280 	atomic_add_long(&tty_nin, len);
1281 
1282 	if (ttyhook_hashook(tp, rint_bypass))
1283 		return ttyhook_rint_bypass(tp, buf, len);
1284 
1285 	ret = ttyinq_write(&tp->t_inq, buf, len, 0);
1286 	ttyinq_canonicalize(&tp->t_inq);
1287 	if (ret < len)
1288 		tty_hiwat_in_block(tp);
1289 
1290 	return (ret);
1291 }
1292 
1293 void
ttydisc_rint_done(struct tty * tp)1294 ttydisc_rint_done(struct tty *tp)
1295 {
1296 
1297 	tty_assert_locked(tp);
1298 
1299 	if (ttyhook_hashook(tp, rint_done))
1300 		ttyhook_rint_done(tp);
1301 
1302 	/* Wake up readers. */
1303 	tty_wakeup(tp, FREAD);
1304 	/* Wake up driver for echo. */
1305 	ttydevsw_outwakeup(tp);
1306 }
1307 
1308 size_t
ttydisc_rint_poll(struct tty * tp)1309 ttydisc_rint_poll(struct tty *tp)
1310 {
1311 	size_t l;
1312 
1313 	tty_assert_locked(tp);
1314 
1315 	if (ttyhook_hashook(tp, rint_poll))
1316 		return ttyhook_rint_poll(tp);
1317 
1318 	/*
1319 	 * XXX: Still allow character input when there's no space in the
1320 	 * buffers, but we haven't entered the high watermark. This is
1321 	 * to allow backspace characters to be inserted when in
1322 	 * canonical mode.
1323 	 */
1324 	l = ttyinq_bytesleft(&tp->t_inq);
1325 	if (l == 0 && (tp->t_flags & TF_HIWAT_IN) == 0)
1326 		return (1);
1327 
1328 	return (l);
1329 }
1330 
1331 static void
ttydisc_wakeup_watermark(struct tty * tp)1332 ttydisc_wakeup_watermark(struct tty *tp)
1333 {
1334 	size_t c;
1335 
1336 	c = ttyoutq_bytesleft(&tp->t_outq);
1337 	if (tp->t_flags & TF_HIWAT_OUT) {
1338 		/* Only allow us to run when we're below the watermark. */
1339 		if (c < tp->t_outlow)
1340 			return;
1341 
1342 		/* Reset the watermark. */
1343 		tp->t_flags &= ~TF_HIWAT_OUT;
1344 	} else {
1345 		/* Only run when we have data at all. */
1346 		if (c == 0)
1347 			return;
1348 	}
1349 	tty_wakeup(tp, FWRITE);
1350 }
1351 
1352 size_t
ttydisc_getc(struct tty * tp,void * buf,size_t len)1353 ttydisc_getc(struct tty *tp, void *buf, size_t len)
1354 {
1355 
1356 	tty_assert_locked(tp);
1357 
1358 	if (tp->t_flags & TF_STOPPED)
1359 		return (0);
1360 
1361 	if (ttyhook_hashook(tp, getc_inject))
1362 		return ttyhook_getc_inject(tp, buf, len);
1363 
1364 	len = ttyoutq_read(&tp->t_outq, buf, len);
1365 
1366 	if (ttyhook_hashook(tp, getc_capture))
1367 		ttyhook_getc_capture(tp, buf, len);
1368 
1369 	ttydisc_wakeup_watermark(tp);
1370 	atomic_add_long(&tty_nout, len);
1371 
1372 	return (len);
1373 }
1374 
1375 int
ttydisc_getc_uio(struct tty * tp,struct uio * uio)1376 ttydisc_getc_uio(struct tty *tp, struct uio *uio)
1377 {
1378 	int error = 0;
1379 	ssize_t obytes = uio->uio_resid;
1380 	size_t len;
1381 	char buf[TTY_STACKBUF];
1382 
1383 	tty_assert_locked(tp);
1384 
1385 	if (tp->t_flags & TF_STOPPED)
1386 		return (0);
1387 
1388 	/*
1389 	 * When a TTY hook is attached, we cannot perform unbuffered
1390 	 * copying to userspace. Just call ttydisc_getc() and
1391 	 * temporarily store data in a shadow buffer.
1392 	 */
1393 	if (ttyhook_hashook(tp, getc_capture) ||
1394 	    ttyhook_hashook(tp, getc_inject)) {
1395 		while (uio->uio_resid > 0) {
1396 			/* Read to shadow buffer. */
1397 			len = ttydisc_getc(tp, buf,
1398 			    MIN(uio->uio_resid, sizeof buf));
1399 			if (len == 0)
1400 				break;
1401 
1402 			/* Copy to userspace. */
1403 			tty_unlock(tp);
1404 			error = uiomove(buf, len, uio);
1405 			tty_lock(tp);
1406 
1407 			if (error != 0)
1408 				break;
1409 		}
1410 	} else {
1411 		error = ttyoutq_read_uio(&tp->t_outq, tp, uio);
1412 
1413 		ttydisc_wakeup_watermark(tp);
1414 		atomic_add_long(&tty_nout, obytes - uio->uio_resid);
1415 	}
1416 
1417 	return (error);
1418 }
1419 
1420 size_t
ttydisc_getc_poll(struct tty * tp)1421 ttydisc_getc_poll(struct tty *tp)
1422 {
1423 
1424 	tty_assert_locked(tp);
1425 
1426 	if (tp->t_flags & TF_STOPPED)
1427 		return (0);
1428 
1429 	if (ttyhook_hashook(tp, getc_poll))
1430 		return ttyhook_getc_poll(tp);
1431 
1432 	return ttyoutq_bytesused(&tp->t_outq);
1433 }
1434 
1435 /*
1436  * XXX: not really related to the TTYDISC, but we'd better put
1437  * tty_putchar() here, because we need to perform proper output
1438  * processing.
1439  */
1440 
1441 int
tty_putstrn(struct tty * tp,const char * p,size_t n)1442 tty_putstrn(struct tty *tp, const char *p, size_t n)
1443 {
1444 	size_t i;
1445 
1446 	tty_assert_locked(tp);
1447 
1448 	if (tty_gone(tp))
1449 		return (-1);
1450 
1451 	for (i = 0; i < n; i++)
1452 		ttydisc_echo_force(tp, p[i], 0);
1453 
1454 	tp->t_writepos = tp->t_column;
1455 	ttyinq_reprintpos_set(&tp->t_inq);
1456 
1457 	ttydevsw_outwakeup(tp);
1458 	return (0);
1459 }
1460 
1461 int
tty_putchar(struct tty * tp,char c)1462 tty_putchar(struct tty *tp, char c)
1463 {
1464 	return (tty_putstrn(tp, &c, 1));
1465 }
1466