xref: /freebsd/sys/kern/tty_ttydisc.c (revision 824f934bf9d5fcb34dd6c97d650a26823158abf1)
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/param.h>
33 #include <sys/fcntl.h>
34 #include <sys/filio.h>
35 #include <sys/kernel.h>
36 #include <sys/signal.h>
37 #include <sys/sysctl.h>
38 #include <sys/systm.h>
39 #include <sys/tty.h>
40 #include <sys/ttycom.h>
41 #include <sys/ttydefaults.h>
42 #include <sys/uio.h>
43 #include <sys/vnode.h>
44 
45 #include <teken/teken.h>
46 #include <teken/teken_wcwidth.h>
47 
48 /*
49  * Standard TTYDISC `termios' line discipline.
50  */
51 
52 /* Statistics. */
53 static unsigned long tty_nin = 0;
54 SYSCTL_ULONG(_kern, OID_AUTO, tty_nin, CTLFLAG_RD,
55 	&tty_nin, 0, "Total amount of bytes received");
56 static unsigned long tty_nout = 0;
57 SYSCTL_ULONG(_kern, OID_AUTO, tty_nout, CTLFLAG_RD,
58 	&tty_nout, 0, "Total amount of bytes transmitted");
59 
60 /* termios comparison macro's. */
61 #define	CMP_CC(v,c) (tp->t_termios.c_cc[v] != _POSIX_VDISABLE && \
62 			tp->t_termios.c_cc[v] == (c))
63 #define	CMP_FLAG(field,opt) (tp->t_termios.c_ ## field ## flag & (opt))
64 
65 /* Characters that cannot be modified through c_cc. */
66 #define CTAB	'\t'
67 #define CNL	'\n'
68 #define CCR	'\r'
69 
70 /* Character is a control character. */
71 #define CTL_VALID(c)	((c) == 0x7f || (unsigned char)(c) < 0x20)
72 /* Control character should be processed on echo. */
73 #define CTL_ECHO(c,q)	(!(q) && ((c) == CERASE2 || (c) == CTAB || \
74     (c) == CNL || (c) == CCR))
75 /* Control character should be printed using ^X notation. */
76 #define CTL_PRINT(c,q)	((c) == 0x7f || ((unsigned char)(c) < 0x20 && \
77     ((q) || ((c) != CTAB && (c) != CNL))))
78 /* Character is whitespace. */
79 #define CTL_WHITE(c)	((c) == ' ' || (c) == CTAB)
80 /* Character is alphanumeric. */
81 #define CTL_ALNUM(c)	(((c) >= '0' && (c) <= '9') || \
82     ((c) >= 'a' && (c) <= 'z') || ((c) >= 'A' && (c) <= 'Z'))
83 /* Character is UTF8-encoded. */
84 #define CTL_UTF8(c) (!!((c) & 0x80))
85 /* Character is a UTF8 continuation byte. */
86 #define CTL_UTF8_CONT(c) (((c) & 0xc0) == 0x80)
87 
88 #define	TTY_STACKBUF	256
89 #define UTF8_STACKBUF 4
90 
91 void
ttydisc_open(struct tty * tp)92 ttydisc_open(struct tty *tp)
93 {
94 	ttydisc_optimize(tp);
95 }
96 
97 void
ttydisc_close(struct tty * tp)98 ttydisc_close(struct tty *tp)
99 {
100 
101 	/* Clean up our flags when leaving the discipline. */
102 	tp->t_flags &= ~(TF_STOPPED|TF_HIWAT|TF_ZOMBIE);
103 	tp->t_termios.c_lflag &= ~FLUSHO;
104 
105 	/*
106 	 * POSIX states that we must drain output and flush input on
107 	 * last close.  Draining has already been done if possible.
108 	 */
109 	tty_flush(tp, FREAD | FWRITE);
110 
111 	if (ttyhook_hashook(tp, close))
112 		ttyhook_close(tp);
113 }
114 
115 /*
116  * Populate our break array; it should likely be at least 4 bytes in size to
117  * allow for \n, VEOF, and VEOL.
118  */
119 static void
ttydisc_read_break(struct tty * tp,char * breakc,size_t breaksz)120 ttydisc_read_break(struct tty *tp, char *breakc, size_t breaksz)
121 {
122 	size_t n = 0;
123 
124 	MPASS(breaksz != 0);
125 
126 	breakc[n++] = CNL;
127 #define BREAK_ADD(c) do { \
128 	MPASS(n < breaksz - 1);	/* NUL terminated */	\
129 	if (tp->t_termios.c_cc[c] != _POSIX_VDISABLE)	\
130 		breakc[n++] = tp->t_termios.c_cc[c];	\
131 } while (0)
132 	/* Determine which characters we should trigger on. */
133 	BREAK_ADD(VEOF);
134 	BREAK_ADD(VEOL);
135 #undef BREAK_ADD
136 
137 	breakc[n] = '\0';
138 }
139 
140 size_t
ttydisc_bytesavail(struct tty * tp)141 ttydisc_bytesavail(struct tty *tp)
142 {
143 	size_t clen;
144 	char breakc[4];
145 	unsigned char lastc = _POSIX_VDISABLE;
146 
147 	clen = ttyinq_bytescanonicalized(&tp->t_inq);
148 	if (!CMP_FLAG(l, ICANON) || clen == 0)
149 		return (clen);
150 
151 	ttydisc_read_break(tp, &breakc[0], sizeof(breakc));
152 	clen = ttyinq_findchar(&tp->t_inq, breakc, clen, &lastc);
153 
154 	/*
155 	 * We might have a partial line canonicalized in the input queue if we,
156 	 * for instance, switched to ICANON after taking some input in raw mode.
157 	 * In this case, read(2) will block because we only have a partial line.
158 	 */
159 	if (lastc == _POSIX_VDISABLE)
160 		return (0);
161 
162 	/* If VEOF was our terminal, it must be discarded (not counted). */
163 	if (CMP_CC(VEOF, lastc))
164 		clen--;
165 
166 	return (clen);
167 }
168 
169 void
ttydisc_canonicalize(struct tty * tp)170 ttydisc_canonicalize(struct tty *tp)
171 {
172 	char breakc[4];
173 
174 	/*
175 	 * If we're in non-canonical mode, it's as easy as just canonicalizing
176 	 * the current partial line.
177 	 */
178 	if (!CMP_FLAG(l, ICANON)) {
179 		ttyinq_canonicalize(&tp->t_inq);
180 		return;
181 	}
182 
183 	/*
184 	 * For canonical mode, we need to rescan the buffer for the last EOL
185 	 * indicator.
186 	 */
187 	ttydisc_read_break(tp, &breakc[0], sizeof(breakc));
188 	ttyinq_canonicalize_break(&tp->t_inq, breakc);
189 }
190 
191 static int
ttydisc_read_canonical(struct tty * tp,struct uio * uio,int ioflag)192 ttydisc_read_canonical(struct tty *tp, struct uio *uio, int ioflag)
193 {
194 	char breakc[4]; /* enough to hold \n, VEOF and VEOL. */
195 	int error;
196 	size_t clen, flen = 0;
197 	unsigned char lastc = _POSIX_VDISABLE;
198 
199 	ttydisc_read_break(tp, &breakc[0], sizeof(breakc));
200 
201 	do {
202 		error = tty_wait_background(tp, curthread, SIGTTIN,
203 		    LA_UNLOCKED);
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 		    LA_UNLOCKED);
285 		if (error)
286 			return (error);
287 
288 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
289 		    uio->uio_resid, 0);
290 		if (error)
291 			return (error);
292 		if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
293 			return (0);
294 
295 		/* We have to wait for more. */
296 		if (tp->t_flags & TF_ZOMBIE)
297 			return (0);
298 		else if (ioflag & IO_NDELAY)
299 			return (EWOULDBLOCK);
300 
301 		error = tty_wait(tp, &tp->t_inwait);
302 		if (error)
303 			return (error);
304 	}
305 }
306 
307 static int
ttydisc_read_raw_read_timer(struct tty * tp,struct uio * uio,int ioflag,int oresid)308 ttydisc_read_raw_read_timer(struct tty *tp, struct uio *uio, int ioflag,
309     int oresid)
310 {
311 	size_t vmin = MAX(tp->t_termios.c_cc[VMIN], 1);
312 	unsigned int vtime = tp->t_termios.c_cc[VTIME];
313 	struct timeval end, now, left;
314 	int error, hz;
315 
316 	MPASS(tp->t_termios.c_cc[VTIME] != 0);
317 
318 	/* Determine when the read should be expired. */
319 	end.tv_sec = vtime / 10;
320 	end.tv_usec = (vtime % 10) * 100000;
321 	getmicrotime(&now);
322 	timevaladd(&end, &now);
323 
324 	for (;;) {
325 		error = tty_wait_background(tp, curthread, SIGTTIN,
326 		    LA_UNLOCKED);
327 		if (error)
328 			return (error);
329 
330 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
331 		    uio->uio_resid, 0);
332 		if (error)
333 			return (error);
334 		if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
335 			return (0);
336 
337 		/* Calculate how long we should wait. */
338 		getmicrotime(&now);
339 		if (timevalcmp(&now, &end, >))
340 			return (0);
341 		left = end;
342 		timevalsub(&left, &now);
343 		hz = tvtohz(&left);
344 
345 		/*
346 		 * We have to wait for more. If the timer expires, we
347 		 * should return a 0-byte read.
348 		 */
349 		if (tp->t_flags & TF_ZOMBIE)
350 			return (0);
351 		else if (ioflag & IO_NDELAY)
352 			return (EWOULDBLOCK);
353 
354 		error = tty_timedwait(tp, &tp->t_inwait, hz);
355 		if (error)
356 			return (error == EWOULDBLOCK ? 0 : error);
357 	}
358 
359 	return (0);
360 }
361 
362 static int
ttydisc_read_raw_interbyte_timer(struct tty * tp,struct uio * uio,int ioflag)363 ttydisc_read_raw_interbyte_timer(struct tty *tp, struct uio *uio, int ioflag)
364 {
365 	size_t vmin = tp->t_termios.c_cc[VMIN];
366 	ssize_t oresid = uio->uio_resid;
367 	int error;
368 
369 	MPASS(tp->t_termios.c_cc[VMIN] != 0);
370 	MPASS(tp->t_termios.c_cc[VTIME] != 0);
371 
372 	/*
373 	 * When using the interbyte timer, the timer should be started
374 	 * after the first byte has been received. We just call into the
375 	 * generic read timer code after we've received the first byte.
376 	 */
377 
378 	for (;;) {
379 		error = tty_wait_background(tp, curthread, SIGTTIN,
380 		    LA_UNLOCKED);
381 		if (error)
382 			return (error);
383 
384 		error = ttyinq_read_uio(&tp->t_inq, tp, uio,
385 		    uio->uio_resid, 0);
386 		if (error)
387 			return (error);
388 		if (uio->uio_resid == 0 || (oresid - uio->uio_resid) >= vmin)
389 			return (0);
390 
391 		/*
392 		 * Not enough data, but we did receive some, which means
393 		 * we'll now start using the interbyte timer.
394 		 */
395 		if (oresid != uio->uio_resid)
396 			break;
397 
398 		/* We have to wait for more. */
399 		if (tp->t_flags & TF_ZOMBIE)
400 			return (0);
401 		else if (ioflag & IO_NDELAY)
402 			return (EWOULDBLOCK);
403 
404 		error = tty_wait(tp, &tp->t_inwait);
405 		if (error)
406 			return (error);
407 	}
408 
409 	return ttydisc_read_raw_read_timer(tp, uio, ioflag, oresid);
410 }
411 
412 int
ttydisc_read(struct tty * tp,struct uio * uio,int ioflag)413 ttydisc_read(struct tty *tp, struct uio *uio, int ioflag)
414 {
415 	int error;
416 
417 	tty_assert_locked(tp);
418 
419 	if (uio->uio_resid == 0)
420 		return (0);
421 
422 	if (CMP_FLAG(l, ICANON))
423 		error = ttydisc_read_canonical(tp, uio, ioflag);
424 	else if (tp->t_termios.c_cc[VTIME] == 0)
425 		error = ttydisc_read_raw_no_timer(tp, uio, ioflag);
426 	else if (tp->t_termios.c_cc[VMIN] == 0)
427 		error = ttydisc_read_raw_read_timer(tp, uio, ioflag,
428 		    uio->uio_resid);
429 	else
430 		error = ttydisc_read_raw_interbyte_timer(tp, uio, ioflag);
431 
432 	if (ttyinq_bytesleft(&tp->t_inq) >= tp->t_inlow ||
433 	    ttyinq_bytescanonicalized(&tp->t_inq) == 0) {
434 		/* Unset the input watermark when we've got enough space. */
435 		tty_hiwat_in_unblock(tp);
436 	}
437 
438 	return (error);
439 }
440 
441 static __inline unsigned int
ttydisc_findchar(const char * obstart,unsigned int oblen)442 ttydisc_findchar(const char *obstart, unsigned int oblen)
443 {
444 	const char *c = obstart;
445 
446 	while (oblen--) {
447 		if (CTL_VALID(*c))
448 			break;
449 		c++;
450 	}
451 
452 	return (c - obstart);
453 }
454 
455 static int
ttydisc_write_oproc(struct tty * tp,char c)456 ttydisc_write_oproc(struct tty *tp, char c)
457 {
458 	unsigned int scnt, error;
459 
460 	MPASS(CMP_FLAG(o, OPOST));
461 	MPASS(CTL_VALID(c));
462 
463 #define PRINT_NORMAL() ttyoutq_write_nofrag(&tp->t_outq, &c, 1)
464 	switch (c) {
465 	case CEOF:
466 		/* End-of-text dropping. */
467 		if (CMP_FLAG(o, ONOEOT))
468 			return (0);
469 		return PRINT_NORMAL();
470 
471 	case CERASE2:
472 		/* Handle backspace to fix tab expansion. */
473 		if (PRINT_NORMAL() != 0)
474 			return (-1);
475 		if (tp->t_column > 0)
476 			tp->t_column--;
477 		return (0);
478 
479 	case CTAB:
480 		/* Tab expansion. */
481 		scnt = 8 - (tp->t_column & 7);
482 		if (CMP_FLAG(o, TAB3)) {
483 			error = ttyoutq_write_nofrag(&tp->t_outq,
484 			    "        ", scnt);
485 		} else {
486 			error = PRINT_NORMAL();
487 		}
488 		if (error)
489 			return (-1);
490 
491 		tp->t_column += scnt;
492 		MPASS((tp->t_column % 8) == 0);
493 		return (0);
494 
495 	case CNL:
496 		/* Newline conversion. */
497 		if (CMP_FLAG(o, ONLCR)) {
498 			/* Convert \n to \r\n. */
499 			error = ttyoutq_write_nofrag(&tp->t_outq, "\r\n", 2);
500 		} else {
501 			error = PRINT_NORMAL();
502 		}
503 		if (error)
504 			return (-1);
505 
506 		if (CMP_FLAG(o, ONLCR|ONLRET)) {
507 			tp->t_column = tp->t_writepos = 0;
508 			ttyinq_reprintpos_set(&tp->t_inq);
509 		}
510 		return (0);
511 
512 	case CCR:
513 		/* Carriage return to newline conversion. */
514 		if (CMP_FLAG(o, OCRNL))
515 			c = CNL;
516 		/* Omit carriage returns on column 0. */
517 		if (CMP_FLAG(o, ONOCR) && tp->t_column == 0)
518 			return (0);
519 		if (PRINT_NORMAL() != 0)
520 			return (-1);
521 
522 		tp->t_column = tp->t_writepos = 0;
523 		ttyinq_reprintpos_set(&tp->t_inq);
524 		return (0);
525 	}
526 
527 	/*
528 	 * Invisible control character. Print it, but don't
529 	 * increase the column count.
530 	 */
531 	return PRINT_NORMAL();
532 #undef PRINT_NORMAL
533 }
534 
535 /*
536  * Just like the old TTY implementation, we need to copy data in chunks
537  * into a temporary buffer. One of the reasons why we need to do this,
538  * is because output processing (only TAB3 though) may allow the buffer
539  * to grow eight times.
540  */
541 int
ttydisc_write(struct tty * tp,struct uio * uio,int ioflag)542 ttydisc_write(struct tty *tp, struct uio *uio, int ioflag)
543 {
544 	char ob[TTY_STACKBUF];
545 	char *obstart;
546 	int error = 0;
547 	unsigned int oblen = 0;
548 
549 	tty_assert_locked(tp);
550 
551 	if (tp->t_flags & TF_ZOMBIE)
552 		return (EIO);
553 
554 	/*
555 	 * We don't need to check whether the process is the foreground
556 	 * process group or if we have a carrier. This is already done
557 	 * in ttydev_write().
558 	 */
559 
560 	while (uio->uio_resid > 0) {
561 		unsigned int nlen;
562 
563 		MPASS(oblen == 0);
564 
565 		if (CMP_FLAG(l, FLUSHO)) {
566 			uio->uio_offset += uio->uio_resid;
567 			uio->uio_resid = 0;
568 			return (0);
569 		}
570 
571 		/* Step 1: read data. */
572 		obstart = ob;
573 		nlen = MIN(uio->uio_resid, sizeof ob);
574 		tty_unlock(tp);
575 		error = uiomove(ob, nlen, uio);
576 		tty_lock(tp);
577 		if (error != 0)
578 			break;
579 		oblen = nlen;
580 
581 		if (tty_gone(tp)) {
582 			error = ENXIO;
583 			break;
584 		}
585 
586 		MPASS(oblen > 0);
587 
588 		/* Step 2: process data. */
589 		do {
590 			unsigned int plen, wlen;
591 
592 			if (CMP_FLAG(l, FLUSHO)) {
593 				uio->uio_offset += uio->uio_resid;
594 				uio->uio_resid = 0;
595 				return (0);
596 			}
597 
598 			/* Search for special characters for post processing. */
599 			if (CMP_FLAG(o, OPOST)) {
600 				plen = ttydisc_findchar(obstart, oblen);
601 			} else {
602 				plen = oblen;
603 			}
604 
605 			if (plen == 0) {
606 				/*
607 				 * We're going to process a character
608 				 * that needs processing
609 				 */
610 				if (ttydisc_write_oproc(tp, *obstart) == 0) {
611 					obstart++;
612 					oblen--;
613 
614 					tp->t_writepos = tp->t_column;
615 					ttyinq_reprintpos_set(&tp->t_inq);
616 					continue;
617 				}
618 			} else {
619 				/* We're going to write regular data. */
620 				wlen = ttyoutq_write(&tp->t_outq, obstart, plen);
621 				obstart += wlen;
622 				oblen -= wlen;
623 				tp->t_column += wlen;
624 
625 				tp->t_writepos = tp->t_column;
626 				ttyinq_reprintpos_set(&tp->t_inq);
627 
628 				if (wlen == plen)
629 					continue;
630 			}
631 
632 			/* Watermark reached. Try to sleep. */
633 			tp->t_flags |= TF_HIWAT_OUT;
634 
635 			if (ioflag & IO_NDELAY) {
636 				error = EWOULDBLOCK;
637 				goto done;
638 			}
639 
640 			/*
641 			 * The driver may write back the data
642 			 * synchronously. Be sure to check the high
643 			 * water mark before going to sleep.
644 			 */
645 			ttydevsw_outwakeup(tp);
646 			if ((tp->t_flags & TF_HIWAT_OUT) == 0)
647 				continue;
648 
649 			error = tty_wait(tp, &tp->t_outwait);
650 			if (error)
651 				goto done;
652 
653 			if (tp->t_flags & TF_ZOMBIE) {
654 				error = EIO;
655 				goto done;
656 			}
657 		} while (oblen > 0);
658 	}
659 
660 done:
661 	if (!tty_gone(tp))
662 		ttydevsw_outwakeup(tp);
663 
664 	/*
665 	 * Add the amount of bytes that we didn't process back to the
666 	 * uio counters. We need to do this to make sure write() doesn't
667 	 * count the bytes we didn't store in the queue.
668 	 */
669 	uio->uio_resid += oblen;
670 	return (error);
671 }
672 
673 void
ttydisc_optimize(struct tty * tp)674 ttydisc_optimize(struct tty *tp)
675 {
676 	tty_assert_locked(tp);
677 
678 	if (ttyhook_hashook(tp, rint_bypass)) {
679 		tp->t_flags |= TF_BYPASS;
680 	} else if (ttyhook_hashook(tp, rint)) {
681 		tp->t_flags &= ~TF_BYPASS;
682 	} else if (!CMP_FLAG(i, ICRNL|IGNCR|IMAXBEL|INLCR|ISTRIP|IXON) &&
683 	    (!CMP_FLAG(i, BRKINT) || CMP_FLAG(i, IGNBRK)) &&
684 	    (!CMP_FLAG(i, PARMRK) ||
685 		CMP_FLAG(i, IGNPAR|IGNBRK) == (IGNPAR|IGNBRK)) &&
686 	    !CMP_FLAG(l, ECHO|ICANON|IEXTEN|ISIG|PENDIN)) {
687 		tp->t_flags |= TF_BYPASS;
688 	} else {
689 		tp->t_flags &= ~TF_BYPASS;
690 	}
691 }
692 
693 void
ttydisc_modem(struct tty * tp,int open)694 ttydisc_modem(struct tty *tp, int open)
695 {
696 
697 	tty_assert_locked(tp);
698 
699 	if (open)
700 		cv_broadcast(&tp->t_dcdwait);
701 
702 	/*
703 	 * Ignore modem status lines when CLOCAL is turned on, but don't
704 	 * enter the zombie state when the TTY isn't opened, because
705 	 * that would cause the TTY to be in zombie state after being
706 	 * opened.
707 	 */
708 	if (!tty_opened(tp) || CMP_FLAG(c, CLOCAL))
709 		return;
710 
711 	if (open == 0) {
712 		/*
713 		 * Lost carrier.
714 		 */
715 		tp->t_flags |= TF_ZOMBIE;
716 
717 		tty_signal_sessleader(tp, SIGHUP);
718 		tty_flush(tp, FREAD|FWRITE);
719 	} else {
720 		/*
721 		 * Carrier is back again.
722 		 */
723 
724 		/* XXX: what should we do here? */
725 	}
726 }
727 
728 static int
ttydisc_echo_force(struct tty * tp,char c,int quote)729 ttydisc_echo_force(struct tty *tp, char c, int quote)
730 {
731 
732 	if (CMP_FLAG(l, FLUSHO))
733 		return 0;
734 
735 	if (CMP_FLAG(o, OPOST) && CTL_ECHO(c, quote)) {
736 		/*
737 		 * Only perform postprocessing when OPOST is turned on
738 		 * and the character is an unquoted BS/TB/NL/CR.
739 		 */
740 		return ttydisc_write_oproc(tp, c);
741 	} else if (CMP_FLAG(l, ECHOCTL) && CTL_PRINT(c, quote)) {
742 		/*
743 		 * Only use ^X notation when ECHOCTL is turned on and
744 		 * we've got an quoted control character.
745 		 *
746 		 * Print backspaces when echoing an end-of-file.
747 		 */
748 		char ob[4] = "^?\b\b";
749 
750 		/* Print ^X notation. */
751 		if (c != 0x7f)
752 			ob[1] = c + 'A' - 1;
753 
754 		if (!quote && CMP_CC(VEOF, c)) {
755 			return ttyoutq_write_nofrag(&tp->t_outq, ob, 4);
756 		} else {
757 			tp->t_column += 2;
758 			return ttyoutq_write_nofrag(&tp->t_outq, ob, 2);
759 		}
760 	} else {
761 		/* Can just be printed. */
762 		tp->t_column++;
763 		return ttyoutq_write_nofrag(&tp->t_outq, &c, 1);
764 	}
765 }
766 
767 static int
ttydisc_echo(struct tty * tp,char c,int quote)768 ttydisc_echo(struct tty *tp, char c, int quote)
769 {
770 
771 	/*
772 	 * Only echo characters when ECHO is turned on, or ECHONL when
773 	 * the character is an unquoted newline.
774 	 */
775 	if (!CMP_FLAG(l, ECHO) &&
776 	    (!CMP_FLAG(l, ECHONL) || c != CNL || quote))
777 		return (0);
778 
779 	return ttydisc_echo_force(tp, c, quote);
780 }
781 
782 static void
ttydisc_reprint_char(void * d,char c,int quote)783 ttydisc_reprint_char(void *d, char c, int quote)
784 {
785 	struct tty *tp = d;
786 
787 	ttydisc_echo(tp, c, quote);
788 }
789 
790 static void
ttydisc_reprint(struct tty * tp)791 ttydisc_reprint(struct tty *tp)
792 {
793 	cc_t c;
794 
795 	/* Print  ^R\n, followed by the line. */
796 	c = tp->t_termios.c_cc[VREPRINT];
797 	if (c != _POSIX_VDISABLE)
798 		ttydisc_echo(tp, c, 0);
799 	ttydisc_echo(tp, CNL, 0);
800 	ttyinq_reprintpos_reset(&tp->t_inq);
801 
802 	ttyinq_line_iterate_from_linestart(&tp->t_inq, ttydisc_reprint_char, tp);
803 }
804 
805 struct ttydisc_recalc_length {
806 	struct tty *tp;
807 	unsigned int curlen;
808 };
809 
810 static void
ttydisc_recalc_charlength(void * d,char c,int quote)811 ttydisc_recalc_charlength(void *d, char c, int quote)
812 {
813 	struct ttydisc_recalc_length *data = d;
814 	struct tty *tp = data->tp;
815 
816 	if (CTL_PRINT(c, quote)) {
817 		if (CMP_FLAG(l, ECHOCTL))
818 			data->curlen += 2;
819 	} else if (c == CTAB) {
820 		data->curlen += 8 - (data->curlen & 7);
821 	} else {
822 		data->curlen++;
823 	}
824 }
825 
826 static unsigned int
ttydisc_recalc_linelength(struct tty * tp)827 ttydisc_recalc_linelength(struct tty *tp)
828 {
829 	struct ttydisc_recalc_length data = { tp, tp->t_writepos };
830 
831 	ttyinq_line_iterate_from_reprintpos(&tp->t_inq,
832 	    ttydisc_recalc_charlength, &data);
833 	return (data.curlen);
834 }
835 
836 static int
ttydisc_rubchar(struct tty * tp)837 ttydisc_rubchar(struct tty *tp)
838 {
839 	char c;
840 	int quote;
841 	unsigned int prevpos, tablen;
842 
843 	if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
844 		return (-1);
845 	ttyinq_unputchar(&tp->t_inq);
846 
847 	if (CMP_FLAG(l, ECHO)) {
848 		/*
849 		 * Remove the character from the screen. This is even
850 		 * safe for characters that span multiple characters
851 		 * (tabs, quoted, etc).
852 		 */
853 		if (tp->t_writepos >= tp->t_column) {
854 			/* Retype the sentence. */
855 			ttydisc_reprint(tp);
856 		} else if (CMP_FLAG(l, ECHOE)) {
857 			if (CTL_PRINT(c, quote)) {
858 				/* Remove ^X formatted chars. */
859 				if (CMP_FLAG(l, ECHOCTL)) {
860 					tp->t_column -= 2;
861 					ttyoutq_write_nofrag(&tp->t_outq,
862 					    "\b\b  \b\b", 6);
863 				}
864 			} else if (c == ' ') {
865 				/* Space character needs no rubbing. */
866 				tp->t_column -= 1;
867 				ttyoutq_write_nofrag(&tp->t_outq, "\b", 1);
868 			} else if (c == CTAB) {
869 				/*
870 				 * Making backspace work with tabs is
871 				 * quite hard. Recalculate the length of
872 				 * this character and remove it.
873 				 *
874 				 * Because terminal settings could be
875 				 * changed while the line is being
876 				 * inserted, the calculations don't have
877 				 * to be correct. Make sure we keep the
878 				 * tab length within proper bounds.
879 				 */
880 				prevpos = ttydisc_recalc_linelength(tp);
881 				if (prevpos >= tp->t_column)
882 					tablen = 1;
883 				else
884 					tablen = tp->t_column - prevpos;
885 				if (tablen > 8)
886 					tablen = 8;
887 
888 				tp->t_column = prevpos;
889 				ttyoutq_write_nofrag(&tp->t_outq,
890 				    "\b\b\b\b\b\b\b\b", tablen);
891 				return (0);
892 			} else if ((tp->t_termios.c_iflag & IUTF8) != 0 &&
893 			    CTL_UTF8(c)) {
894 				uint8_t bytes[UTF8_STACKBUF] = { 0 };
895 				int curidx = UTF8_STACKBUF - 1, cwidth = 1,
896 				    nb = 0;
897 				teken_char_t codepoint;
898 
899 				/* Save current byte. */
900 				bytes[curidx] = c;
901 				curidx--;
902 				nb++;
903 				/* Loop back through inq until we hit the
904 				 * leading byte. */
905 				while (CTL_UTF8_CONT(c) && nb < UTF8_STACKBUF) {
906 					/*
907 					 * Check if we've reached the beginning
908 					 * of the line.
909 					 */
910 					if (ttyinq_peekchar(&tp->t_inq, &c,
911 					    &quote) != 0)
912 						break;
913 					ttyinq_unputchar(&tp->t_inq);
914 					bytes[curidx] = c;
915 					curidx--;
916 					nb++;
917 				}
918 				/*
919 				 * Shift array so that the leading
920 				 * byte ends up at idx 0.
921 				 */
922 				if (nb < UTF8_STACKBUF)
923 					memmove(&bytes[0], &bytes[curidx + 1],
924 					    nb * sizeof(uint8_t));
925 				/* Check for malformed UTF8 characters. */
926 				if (nb == UTF8_STACKBUF &&
927 				    CTL_UTF8_CONT(bytes[0])) {
928 					/*
929 					 * Place all bytes back into the inq and
930 					 * delete the last byte only.
931 					 */
932 					ttyinq_write(&tp->t_inq, bytes,
933 					    UTF8_STACKBUF, 0);
934 					ttyinq_unputchar(&tp->t_inq);
935 				} else {
936 					/* Find codepoint and width. */
937 					codepoint =
938 					    teken_utf8_bytes_to_codepoint(bytes,
939 						nb);
940 					if (codepoint ==
941 						TEKEN_UTF8_INVALID_CODEPOINT ||
942 					    (cwidth = teken_wcwidth(
943 						 codepoint)) == -1) {
944 						/*
945 						 * Place all bytes back into the
946 						 * inq and fall back to
947 						 * default behaviour.
948 						 */
949 						cwidth = 1;
950 						ttyinq_write(&tp->t_inq, bytes,
951 						    nb, 0);
952 						ttyinq_unputchar(&tp->t_inq);
953 					}
954 				}
955 				tp->t_column -= cwidth;
956 				/*
957 				 * Delete character by punching
958 				 * 'cwidth' spaces over it.
959 				 */
960 				if (cwidth == 1)
961 					ttyoutq_write_nofrag(&tp->t_outq,
962 					    "\b \b", 3);
963 				else if (cwidth == 2)
964 					ttyoutq_write_nofrag(&tp->t_outq,
965 					    "\b\b  \b\b", 6);
966 			} else {
967 				/*
968 				 * Remove a regular character by
969 				 * punching a space over it.
970 				 */
971 				tp->t_column -= 1;
972 				ttyoutq_write_nofrag(&tp->t_outq, "\b \b", 3);
973 			}
974 		} else {
975 			/* Don't print spaces. */
976 			ttydisc_echo(tp, tp->t_termios.c_cc[VERASE], 0);
977 		}
978 	}
979 
980 	return (0);
981 }
982 
983 static void
ttydisc_rubword(struct tty * tp)984 ttydisc_rubword(struct tty *tp)
985 {
986 	char c;
987 	int quote, alnum;
988 
989 	/* Strip whitespace first. */
990 	for (;;) {
991 		if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
992 			return;
993 		if (!CTL_WHITE(c))
994 			break;
995 		ttydisc_rubchar(tp);
996 	}
997 
998 	/*
999 	 * Record whether the last character from the previous iteration
1000 	 * was alphanumeric or not. We need this to implement ALTWERASE.
1001 	 */
1002 	alnum = CTL_ALNUM(c);
1003 	for (;;) {
1004 		ttydisc_rubchar(tp);
1005 
1006 		if (ttyinq_peekchar(&tp->t_inq, &c, &quote) != 0)
1007 			return;
1008 		if (CTL_WHITE(c))
1009 			return;
1010 		if (CMP_FLAG(l, ALTWERASE) && CTL_ALNUM(c) != alnum)
1011 			return;
1012 	}
1013 }
1014 
1015 int
ttydisc_rint(struct tty * tp,char c,int flags)1016 ttydisc_rint(struct tty *tp, char c, int flags)
1017 {
1018 	int signal, quote = 0;
1019 	char ob[3] = { 0xff, 0x00 };
1020 	size_t ol;
1021 
1022 	tty_assert_locked(tp);
1023 
1024 	atomic_add_long(&tty_nin, 1);
1025 
1026 	if (ttyhook_hashook(tp, rint))
1027 		return ttyhook_rint(tp, c, flags);
1028 
1029 	if (tp->t_flags & TF_BYPASS)
1030 		goto processed;
1031 
1032 	if (flags) {
1033 		if (flags & TRE_BREAK) {
1034 			if (CMP_FLAG(i, IGNBRK)) {
1035 				/* Ignore break characters. */
1036 				return (0);
1037 			} else if (CMP_FLAG(i, BRKINT)) {
1038 				/* Generate SIGINT on break. */
1039 				tty_flush(tp, FREAD|FWRITE);
1040 				tty_signal_pgrp(tp, SIGINT);
1041 				return (0);
1042 			} else {
1043 				/* Just print it. */
1044 				goto parmrk;
1045 			}
1046 		} else if (flags & TRE_FRAMING ||
1047 		    (flags & TRE_PARITY && CMP_FLAG(i, INPCK))) {
1048 			if (CMP_FLAG(i, IGNPAR)) {
1049 				/* Ignore bad characters. */
1050 				return (0);
1051 			} else {
1052 				/* Just print it. */
1053 				goto parmrk;
1054 			}
1055 		}
1056 	}
1057 
1058 	/* Allow any character to perform a wakeup. */
1059 	if (CMP_FLAG(i, IXANY)) {
1060 		tp->t_flags &= ~TF_STOPPED;
1061 		tp->t_termios.c_lflag &= ~FLUSHO;
1062 	}
1063 
1064 	/* Remove the top bit. */
1065 	if (CMP_FLAG(i, ISTRIP))
1066 		c &= ~0x80;
1067 
1068 	/* Skip input processing when we want to print it literally. */
1069 	if (tp->t_flags & TF_LITERAL) {
1070 		tp->t_flags &= ~TF_LITERAL;
1071 		quote = 1;
1072 		goto processed;
1073 	}
1074 
1075 	/* Special control characters that are implementation dependent. */
1076 	if (CMP_FLAG(l, IEXTEN)) {
1077 		/* Accept the next character as literal. */
1078 		if (CMP_CC(VLNEXT, c)) {
1079 			if (CMP_FLAG(l, ECHO)) {
1080 				if (CMP_FLAG(l, ECHOE))
1081 					ttyoutq_write_nofrag(&tp->t_outq, "^\b", 2);
1082 				else
1083 					ttydisc_echo(tp, c, 0);
1084 			}
1085 			tp->t_flags |= TF_LITERAL;
1086 			return (0);
1087 		}
1088 		/* Discard processing */
1089 		if (CMP_CC(VDISCARD, c)) {
1090 			if (CMP_FLAG(l, FLUSHO)) {
1091 				tp->t_termios.c_lflag &= ~FLUSHO;
1092 			} else {
1093 				tty_flush(tp, FWRITE);
1094 				ttydisc_echo(tp, c, 0);
1095 				if (tp->t_inq.ti_end > 0)
1096 					ttydisc_reprint(tp);
1097 				tp->t_termios.c_lflag |= FLUSHO;
1098 			}
1099 		}
1100 	}
1101 
1102 	/*
1103 	 * Handle signal processing.
1104 	 */
1105 	if (CMP_FLAG(l, ISIG)) {
1106 		if (CMP_FLAG(l, ICANON|IEXTEN) == (ICANON|IEXTEN)) {
1107 			if (CMP_CC(VSTATUS, c)) {
1108 				tty_signal_pgrp(tp, SIGINFO);
1109 				return (0);
1110 			}
1111 		}
1112 
1113 		/*
1114 		 * When compared to the old implementation, this
1115 		 * implementation also flushes the output queue. POSIX
1116 		 * is really brief about this, but does makes us assume
1117 		 * we have to do so.
1118 		 */
1119 		signal = 0;
1120 		if (CMP_CC(VINTR, c)) {
1121 			signal = SIGINT;
1122 		} else if (CMP_CC(VQUIT, c)) {
1123 			signal = SIGQUIT;
1124 		} else if (CMP_CC(VSUSP, c)) {
1125 			signal = SIGTSTP;
1126 		}
1127 
1128 		if (signal != 0) {
1129 			/*
1130 			 * Echo the character before signalling the
1131 			 * processes.
1132 			 */
1133 			if (!CMP_FLAG(l, NOFLSH))
1134 				tty_flush(tp, FREAD|FWRITE);
1135 			ttydisc_echo(tp, c, 0);
1136 			tty_signal_pgrp(tp, signal);
1137 			return (0);
1138 		}
1139 	}
1140 
1141 	/*
1142 	 * Handle start/stop characters.
1143 	 */
1144 	if (CMP_FLAG(i, IXON)) {
1145 		if (CMP_CC(VSTOP, c)) {
1146 			/* Stop it if we aren't stopped yet. */
1147 			if ((tp->t_flags & TF_STOPPED) == 0) {
1148 				tp->t_flags |= TF_STOPPED;
1149 				return (0);
1150 			}
1151 			/*
1152 			 * Fallthrough:
1153 			 * When VSTART == VSTOP, we should make this key
1154 			 * toggle it.
1155 			 */
1156 			if (!CMP_CC(VSTART, c))
1157 				return (0);
1158 		}
1159 		if (CMP_CC(VSTART, c)) {
1160 			tp->t_flags &= ~TF_STOPPED;
1161 			return (0);
1162 		}
1163 	}
1164 
1165 	/* Conversion of CR and NL. */
1166 	switch (c) {
1167 	case CCR:
1168 		if (CMP_FLAG(i, IGNCR))
1169 			return (0);
1170 		if (CMP_FLAG(i, ICRNL))
1171 			c = CNL;
1172 		break;
1173 	case CNL:
1174 		if (CMP_FLAG(i, INLCR))
1175 			c = CCR;
1176 		break;
1177 	}
1178 
1179 	/* Canonical line editing. */
1180 	if (CMP_FLAG(l, ICANON)) {
1181 		if (CMP_CC(VERASE, c) || CMP_CC(VERASE2, c)) {
1182 			ttydisc_rubchar(tp);
1183 			return (0);
1184 		} else if (CMP_CC(VKILL, c)) {
1185 			while (ttydisc_rubchar(tp) == 0);
1186 			return (0);
1187 		} else if (CMP_FLAG(l, IEXTEN)) {
1188 			if (CMP_CC(VWERASE, c)) {
1189 				ttydisc_rubword(tp);
1190 				return (0);
1191 			} else if (CMP_CC(VREPRINT, c)) {
1192 				ttydisc_reprint(tp);
1193 				return (0);
1194 			}
1195 		}
1196 	}
1197 
1198 processed:
1199 	if (CMP_FLAG(i, PARMRK) && (unsigned char)c == 0xff) {
1200 		/* Print 0xff 0xff. */
1201 		ob[1] = 0xff;
1202 		ol = 2;
1203 		quote = 1;
1204 	} else {
1205 		ob[0] = c;
1206 		ol = 1;
1207 	}
1208 
1209 	goto print;
1210 
1211 parmrk:
1212 	if (CMP_FLAG(i, PARMRK)) {
1213 		/* Prepend 0xff 0x00 0x.. */
1214 		ob[2] = c;
1215 		ol = 3;
1216 		quote = 1;
1217 	} else {
1218 		ob[0] = c;
1219 		ol = 1;
1220 	}
1221 
1222 print:
1223 	/* See if we can store this on the input queue. */
1224 	if (ttyinq_write_nofrag(&tp->t_inq, ob, ol, quote) != 0) {
1225 		if (CMP_FLAG(i, IMAXBEL))
1226 			ttyoutq_write_nofrag(&tp->t_outq, "\a", 1);
1227 
1228 		/*
1229 		 * Prevent a deadlock here. It may be possible that a
1230 		 * user has entered so much data, there is no data
1231 		 * available to read(), but the buffers are full anyway.
1232 		 *
1233 		 * Only enter the high watermark if the device driver
1234 		 * can actually transmit something.
1235 		 */
1236 		if (ttyinq_bytescanonicalized(&tp->t_inq) == 0)
1237 			return (0);
1238 
1239 		tty_hiwat_in_block(tp);
1240 		return (-1);
1241 	}
1242 
1243 	/*
1244 	 * In raw mode, we canonicalize after receiving a single
1245 	 * character. Otherwise, we canonicalize when we receive a
1246 	 * newline, VEOL or VEOF, but only when it isn't quoted.
1247 	 */
1248 	if (!CMP_FLAG(l, ICANON) ||
1249 	    (!quote && (c == CNL || CMP_CC(VEOL, c) || CMP_CC(VEOF, c)))) {
1250 		ttyinq_canonicalize(&tp->t_inq);
1251 	}
1252 
1253 	ttydisc_echo(tp, c, quote);
1254 
1255 	return (0);
1256 }
1257 
1258 size_t
ttydisc_rint_simple(struct tty * tp,const void * buf,size_t len)1259 ttydisc_rint_simple(struct tty *tp, const void *buf, size_t len)
1260 {
1261 	const char *cbuf;
1262 
1263 	if (ttydisc_can_bypass(tp))
1264 		return (ttydisc_rint_bypass(tp, buf, len));
1265 
1266 	for (cbuf = buf; len-- > 0; cbuf++) {
1267 		if (ttydisc_rint(tp, *cbuf, 0) != 0)
1268 			break;
1269 	}
1270 
1271 	return (cbuf - (const char *)buf);
1272 }
1273 
1274 size_t
ttydisc_rint_bypass(struct tty * tp,const void * buf,size_t len)1275 ttydisc_rint_bypass(struct tty *tp, const void *buf, size_t len)
1276 {
1277 	size_t ret;
1278 
1279 	tty_assert_locked(tp);
1280 
1281 	MPASS(tp->t_flags & TF_BYPASS);
1282 
1283 	atomic_add_long(&tty_nin, len);
1284 
1285 	if (ttyhook_hashook(tp, rint_bypass))
1286 		return ttyhook_rint_bypass(tp, buf, len);
1287 
1288 	ret = ttyinq_write(&tp->t_inq, buf, len, 0);
1289 	ttyinq_canonicalize(&tp->t_inq);
1290 	if (ret < len)
1291 		tty_hiwat_in_block(tp);
1292 
1293 	return (ret);
1294 }
1295 
1296 void
ttydisc_rint_done(struct tty * tp)1297 ttydisc_rint_done(struct tty *tp)
1298 {
1299 
1300 	tty_assert_locked(tp);
1301 
1302 	if (ttyhook_hashook(tp, rint_done))
1303 		ttyhook_rint_done(tp);
1304 
1305 	/* Wake up readers. */
1306 	tty_wakeup(tp, FREAD);
1307 	/* Wake up driver for echo. */
1308 	ttydevsw_outwakeup(tp);
1309 }
1310 
1311 size_t
ttydisc_rint_poll(struct tty * tp)1312 ttydisc_rint_poll(struct tty *tp)
1313 {
1314 	size_t l;
1315 
1316 	tty_assert_locked(tp);
1317 
1318 	if (ttyhook_hashook(tp, rint_poll))
1319 		return ttyhook_rint_poll(tp);
1320 
1321 	/*
1322 	 * XXX: Still allow character input when there's no space in the
1323 	 * buffers, but we haven't entered the high watermark. This is
1324 	 * to allow backspace characters to be inserted when in
1325 	 * canonical mode.
1326 	 */
1327 	l = ttyinq_bytesleft(&tp->t_inq);
1328 	if (l == 0 && (tp->t_flags & TF_HIWAT_IN) == 0)
1329 		return (1);
1330 
1331 	return (l);
1332 }
1333 
1334 static void
ttydisc_wakeup_watermark(struct tty * tp)1335 ttydisc_wakeup_watermark(struct tty *tp)
1336 {
1337 	size_t c;
1338 
1339 	c = ttyoutq_bytesleft(&tp->t_outq);
1340 	if (tp->t_flags & TF_HIWAT_OUT) {
1341 		/* Only allow us to run when we're below the watermark. */
1342 		if (c < tp->t_outlow)
1343 			return;
1344 
1345 		/* Reset the watermark. */
1346 		tp->t_flags &= ~TF_HIWAT_OUT;
1347 	} else {
1348 		/* Only run when we have data at all. */
1349 		if (c == 0)
1350 			return;
1351 	}
1352 	tty_wakeup(tp, FWRITE);
1353 }
1354 
1355 size_t
ttydisc_getc(struct tty * tp,void * buf,size_t len)1356 ttydisc_getc(struct tty *tp, void *buf, size_t len)
1357 {
1358 
1359 	tty_assert_locked(tp);
1360 
1361 	if (tp->t_flags & TF_STOPPED)
1362 		return (0);
1363 
1364 	if (ttyhook_hashook(tp, getc_inject))
1365 		return ttyhook_getc_inject(tp, buf, len);
1366 
1367 	len = ttyoutq_read(&tp->t_outq, buf, len);
1368 
1369 	if (ttyhook_hashook(tp, getc_capture))
1370 		ttyhook_getc_capture(tp, buf, len);
1371 
1372 	ttydisc_wakeup_watermark(tp);
1373 	atomic_add_long(&tty_nout, len);
1374 
1375 	return (len);
1376 }
1377 
1378 int
ttydisc_getc_uio(struct tty * tp,struct uio * uio)1379 ttydisc_getc_uio(struct tty *tp, struct uio *uio)
1380 {
1381 	int error = 0;
1382 	ssize_t obytes = uio->uio_resid;
1383 	size_t len;
1384 	char buf[TTY_STACKBUF];
1385 
1386 	tty_assert_locked(tp);
1387 
1388 	if (tp->t_flags & TF_STOPPED)
1389 		return (0);
1390 
1391 	/*
1392 	 * When a TTY hook is attached, we cannot perform unbuffered
1393 	 * copying to userspace. Just call ttydisc_getc() and
1394 	 * temporarily store data in a shadow buffer.
1395 	 */
1396 	if (ttyhook_hashook(tp, getc_capture) ||
1397 	    ttyhook_hashook(tp, getc_inject)) {
1398 		while (uio->uio_resid > 0) {
1399 			/* Read to shadow buffer. */
1400 			len = ttydisc_getc(tp, buf,
1401 			    MIN(uio->uio_resid, sizeof buf));
1402 			if (len == 0)
1403 				break;
1404 
1405 			/* Copy to userspace. */
1406 			tty_unlock(tp);
1407 			error = uiomove(buf, len, uio);
1408 			tty_lock(tp);
1409 
1410 			if (error != 0)
1411 				break;
1412 		}
1413 	} else {
1414 		error = ttyoutq_read_uio(&tp->t_outq, tp, uio);
1415 
1416 		ttydisc_wakeup_watermark(tp);
1417 		atomic_add_long(&tty_nout, obytes - uio->uio_resid);
1418 	}
1419 
1420 	return (error);
1421 }
1422 
1423 size_t
ttydisc_getc_poll(struct tty * tp)1424 ttydisc_getc_poll(struct tty *tp)
1425 {
1426 
1427 	tty_assert_locked(tp);
1428 
1429 	if (tp->t_flags & TF_STOPPED)
1430 		return (0);
1431 
1432 	if (ttyhook_hashook(tp, getc_poll))
1433 		return ttyhook_getc_poll(tp);
1434 
1435 	return ttyoutq_bytesused(&tp->t_outq);
1436 }
1437 
1438 /*
1439  * XXX: not really related to the TTYDISC, but we'd better put
1440  * tty_putchar() here, because we need to perform proper output
1441  * processing.
1442  */
1443 
1444 int
tty_putstrn(struct tty * tp,const char * p,size_t n)1445 tty_putstrn(struct tty *tp, const char *p, size_t n)
1446 {
1447 	size_t i;
1448 
1449 	tty_assert_locked(tp);
1450 
1451 	if (tty_gone(tp))
1452 		return (-1);
1453 
1454 	for (i = 0; i < n; i++)
1455 		ttydisc_echo_force(tp, p[i], 0);
1456 
1457 	tp->t_writepos = tp->t_column;
1458 	ttyinq_reprintpos_set(&tp->t_inq);
1459 
1460 	ttydevsw_outwakeup(tp);
1461 	return (0);
1462 }
1463 
1464 int
tty_putchar(struct tty * tp,char c)1465 tty_putchar(struct tty *tp, char c)
1466 {
1467 	return (tty_putstrn(tp, &c, 1));
1468 }
1469