xref: /csrg-svn/sys/kern/tty.c (revision 29946)
1 /*
2  * Copyright (c) 1982, 1986 Regents of the University of California.
3  * All rights reserved.  The Berkeley software License Agreement
4  * specifies the terms and conditions for redistribution.
5  *
6  *	@(#)tty.c	7.3 (Berkeley) 11/03/86
7  */
8 
9 #include "../machine/reg.h"
10 
11 #include "param.h"
12 #include "systm.h"
13 #include "dir.h"
14 #include "user.h"
15 #include "ioctl.h"
16 #include "tty.h"
17 #include "proc.h"
18 #include "inode.h"
19 #include "file.h"
20 #include "conf.h"
21 #include "buf.h"
22 #include "dkstat.h"
23 #include "uio.h"
24 #include "kernel.h"
25 
26 /*
27  * Table giving parity for characters and indicating
28  * character classes to tty driver.  In particular,
29  * if the low 6 bits are 0, then the character needs
30  * no special processing on output.
31  */
32 
33 char partab[] = {
34 	0001,0201,0201,0001,0201,0001,0001,0201,
35 	0202,0004,0003,0201,0005,0206,0201,0001,
36 	0201,0001,0001,0201,0001,0201,0201,0001,
37 	0001,0201,0201,0001,0201,0001,0001,0201,
38 	0200,0000,0000,0200,0000,0200,0200,0000,
39 	0000,0200,0200,0000,0200,0000,0000,0200,
40 	0000,0200,0200,0000,0200,0000,0000,0200,
41 	0200,0000,0000,0200,0000,0200,0200,0000,
42 	0200,0000,0000,0200,0000,0200,0200,0000,
43 	0000,0200,0200,0000,0200,0000,0000,0200,
44 	0000,0200,0200,0000,0200,0000,0000,0200,
45 	0200,0000,0000,0200,0000,0200,0200,0000,
46 	0000,0200,0200,0000,0200,0000,0000,0200,
47 	0200,0000,0000,0200,0000,0200,0200,0000,
48 	0200,0000,0000,0200,0000,0200,0200,0000,
49 	0000,0200,0200,0000,0200,0000,0000,0201,
50 
51 	/*
52 	 * 7 bit ascii ends with the last character above,
53 	 * but we contine through all 256 codes for the sake
54 	 * of the tty output routines which use special vax
55 	 * instructions which need a 256 character trt table.
56 	 */
57 
58 	0007,0007,0007,0007,0007,0007,0007,0007,
59 	0007,0007,0007,0007,0007,0007,0007,0007,
60 	0007,0007,0007,0007,0007,0007,0007,0007,
61 	0007,0007,0007,0007,0007,0007,0007,0007,
62 	0007,0007,0007,0007,0007,0007,0007,0007,
63 	0007,0007,0007,0007,0007,0007,0007,0007,
64 	0007,0007,0007,0007,0007,0007,0007,0007,
65 	0007,0007,0007,0007,0007,0007,0007,0007,
66 	0007,0007,0007,0007,0007,0007,0007,0007,
67 	0007,0007,0007,0007,0007,0007,0007,0007,
68 	0007,0007,0007,0007,0007,0007,0007,0007,
69 	0007,0007,0007,0007,0007,0007,0007,0007,
70 	0007,0007,0007,0007,0007,0007,0007,0007,
71 	0007,0007,0007,0007,0007,0007,0007,0007,
72 	0007,0007,0007,0007,0007,0007,0007,0007,
73 	0007,0007,0007,0007,0007,0007,0007,0007
74 };
75 
76 /*
77  * Input mapping table-- if an entry is non-zero, when the
78  * corresponding character is typed preceded by "\" the escape
79  * sequence is replaced by the table value.  Mostly used for
80  * upper-case only terminals.
81  */
82 char	maptab[] ={
83 	000,000,000,000,000,000,000,000,
84 	000,000,000,000,000,000,000,000,
85 	000,000,000,000,000,000,000,000,
86 	000,000,000,000,000,000,000,000,
87 	000,'|',000,000,000,000,000,'`',
88 	'{','}',000,000,000,000,000,000,
89 	000,000,000,000,000,000,000,000,
90 	000,000,000,000,000,000,000,000,
91 	000,000,000,000,000,000,000,000,
92 	000,000,000,000,000,000,000,000,
93 	000,000,000,000,000,000,000,000,
94 	000,000,000,000,000,000,'~',000,
95 	000,'A','B','C','D','E','F','G',
96 	'H','I','J','K','L','M','N','O',
97 	'P','Q','R','S','T','U','V','W',
98 	'X','Y','Z',000,000,000,000,000,
99 };
100 
101 short	tthiwat[16] =
102    { 100,100,100,100,100,100,100,200,200,400,400,400,650,650,1300,2000 };
103 short	ttlowat[16] =
104    {  30, 30, 30, 30, 30, 30, 30, 50, 50,120,120,120,125,125,125,125 };
105 
106 struct	ttychars ttydefaults = {
107 	CERASE,	CKILL,	CINTR,	CQUIT,	CSTART,	CSTOP,	CEOF,
108 	CBRK,	CSUSP,	CDSUSP, CRPRNT, CFLUSH, CWERASE,CLNEXT
109 };
110 
111 ttychars(tp)
112 	struct tty *tp;
113 {
114 
115 	tp->t_chars = ttydefaults;
116 }
117 
118 /*
119  * Wait for output to drain, then flush input waiting.
120  */
121 ttywflush(tp)
122 	register struct tty *tp;
123 {
124 
125 	ttywait(tp);
126 	ttyflush(tp, FREAD);
127 }
128 
129 ttywait(tp)
130 	register struct tty *tp;
131 {
132 	register int s = spltty();
133 
134 	while ((tp->t_outq.c_cc || tp->t_state&TS_BUSY) &&
135 	    tp->t_state&TS_CARR_ON) {
136 		(*tp->t_oproc)(tp);
137 		tp->t_state |= TS_ASLEEP;
138 		sleep((caddr_t)&tp->t_outq, TTOPRI);
139 	}
140 	splx(s);
141 }
142 
143 /*
144  * Flush all TTY queues
145  */
146 ttyflush(tp, rw)
147 	register struct tty *tp;
148 {
149 	register s;
150 
151 	s = spltty();
152 	if (rw & FREAD) {
153 		while (getc(&tp->t_canq) >= 0)
154 			;
155 		wakeup((caddr_t)&tp->t_rawq);
156 	}
157 	if (rw & FWRITE) {
158 		wakeup((caddr_t)&tp->t_outq);
159 		tp->t_state &= ~TS_TTSTOP;
160 		(*cdevsw[major(tp->t_dev)].d_stop)(tp, rw);
161 		while (getc(&tp->t_outq) >= 0)
162 			;
163 	}
164 	if (rw & FREAD) {
165 		while (getc(&tp->t_rawq) >= 0)
166 			;
167 		tp->t_rocount = 0;
168 		tp->t_rocol = 0;
169 		tp->t_state &= ~TS_LOCAL;
170 	}
171 	splx(s);
172 }
173 
174 /*
175  * Send stop character on input overflow.
176  */
177 ttyblock(tp)
178 	register struct tty *tp;
179 {
180 	register x;
181 
182 	x = tp->t_rawq.c_cc + tp->t_canq.c_cc;
183 	if (tp->t_rawq.c_cc > TTYHOG) {
184 		ttyflush(tp, FREAD|FWRITE);
185 		tp->t_state &= ~TS_TBLOCK;
186 	}
187 	/*
188 	 * Block further input iff:
189 	 * Current input > threshold AND input is available to user program
190 	 */
191 	if (x >= TTYHOG/2 &&
192 	    ((tp->t_flags & (RAW|CBREAK)) || (tp->t_canq.c_cc > 0))) {
193 		if (putc(tp->t_stopc, &tp->t_outq)==0) {
194 			tp->t_state |= TS_TBLOCK;
195 			ttstart(tp);
196 		}
197 	}
198 }
199 
200 /*
201  * Restart typewriter output following a delay
202  * timeout.
203  * The name of the routine is passed to the timeout
204  * subroutine and it is called during a clock interrupt.
205  */
206 ttrstrt(tp)
207 	register struct tty *tp;
208 {
209 
210 	if (tp == 0)
211 		panic("ttrstrt");
212 	tp->t_state &= ~TS_TIMEOUT;
213 	ttstart(tp);
214 }
215 
216 /*
217  * Start output on the typewriter. It is used from the top half
218  * after some characters have been put on the output queue,
219  * from the interrupt routine to transmit the next
220  * character, and after a timeout has finished.
221  */
222 ttstart(tp)
223 	register struct tty *tp;
224 {
225 	register s;
226 
227 	s = spltty();
228 	if ((tp->t_state & (TS_TIMEOUT|TS_TTSTOP|TS_BUSY)) == 0 &&
229 	    tp->t_oproc)		/* kludge for pty */
230 		(*tp->t_oproc)(tp);
231 	splx(s);
232 }
233 
234 /*
235  * Common code for tty ioctls.
236  */
237 /*ARGSUSED*/
238 ttioctl(tp, com, data, flag)
239 	register struct tty *tp;
240 	caddr_t data;
241 {
242 	int dev = tp->t_dev;
243 	extern int nldisp;
244 	int s;
245 	register int newflags;
246 
247 	/*
248 	 * If the ioctl involves modification,
249 	 * hang if in the background.
250 	 */
251 	switch (com) {
252 
253 	case TIOCSETD:
254 	case TIOCSETP:
255 	case TIOCSETN:
256 	case TIOCFLUSH:
257 	case TIOCSETC:
258 	case TIOCSLTC:
259 	case TIOCSPGRP:
260 	case TIOCLBIS:
261 	case TIOCLBIC:
262 	case TIOCLSET:
263 	case TIOCSTI:
264 	case TIOCSWINSZ:
265 		while (tp->t_line == NTTYDISC &&
266 		   u.u_procp->p_pgrp != tp->t_pgrp && tp == u.u_ttyp &&
267 		   (u.u_procp->p_flag&SVFORK) == 0 &&
268 		   !(u.u_procp->p_sigignore & sigmask(SIGTTOU)) &&
269 		   !(u.u_procp->p_sigmask & sigmask(SIGTTOU))) {
270 			gsignal(u.u_procp->p_pgrp, SIGTTOU);
271 			sleep((caddr_t)&lbolt, TTOPRI);
272 		}
273 		break;
274 	}
275 
276 	/*
277 	 * Process the ioctl.
278 	 */
279 	switch (com) {
280 
281 	/* get discipline number */
282 	case TIOCGETD:
283 		*(int *)data = tp->t_line;
284 		break;
285 
286 	/* set line discipline */
287 	case TIOCSETD: {
288 		register int t = *(int *)data;
289 		int error = 0;
290 
291 		if ((unsigned) t >= nldisp)
292 			return (ENXIO);
293 		if (t != tp->t_line) {
294 			s = spltty();
295 			(*linesw[tp->t_line].l_close)(tp);
296 			error = (*linesw[t].l_open)(dev, tp);
297 			if (error) {
298 				(void) (*linesw[tp->t_line].l_open)(dev, tp);
299 				splx(s);
300 				return (error);
301 			}
302 			tp->t_line = t;
303 			splx(s);
304 		}
305 		break;
306 	}
307 
308 	/* prevent more opens on channel */
309 	case TIOCEXCL:
310 		tp->t_state |= TS_XCLUDE;
311 		break;
312 
313 	case TIOCNXCL:
314 		tp->t_state &= ~TS_XCLUDE;
315 		break;
316 
317 	/* hang up line on last close */
318 	case TIOCHPCL:
319 		tp->t_state |= TS_HUPCLS;
320 		break;
321 
322 	case TIOCFLUSH: {
323 		register int flags = *(int *)data;
324 
325 		if (flags == 0)
326 			flags = FREAD|FWRITE;
327 		else
328 			flags &= FREAD|FWRITE;
329 		ttyflush(tp, flags);
330 		break;
331 	}
332 
333 	/* return number of characters immediately available */
334 	case FIONREAD:
335 		*(off_t *)data = ttnread(tp);
336 		break;
337 
338 	case TIOCOUTQ:
339 		*(int *)data = tp->t_outq.c_cc;
340 		break;
341 
342 	case TIOCSTOP:
343 		s = spltty();
344 		if ((tp->t_state&TS_TTSTOP) == 0) {
345 			tp->t_state |= TS_TTSTOP;
346 			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
347 		}
348 		splx(s);
349 		break;
350 
351 	case TIOCSTART:
352 		s = spltty();
353 		if ((tp->t_state&TS_TTSTOP) || (tp->t_flags&FLUSHO)) {
354 			tp->t_state &= ~TS_TTSTOP;
355 			tp->t_flags &= ~FLUSHO;
356 			ttstart(tp);
357 		}
358 		splx(s);
359 		break;
360 
361 	/*
362 	 * Simulate typing of a character at the terminal.
363 	 */
364 	case TIOCSTI:
365 		if (u.u_uid && (flag & FREAD) == 0)
366 			return (EPERM);
367 		if (u.u_uid && u.u_ttyp != tp)
368 			return (EACCES);
369 		(*linesw[tp->t_line].l_rint)(*(char *)data, tp);
370 		break;
371 
372 	case TIOCSETP:
373 	case TIOCSETN: {
374 		register struct sgttyb *sg = (struct sgttyb *)data;
375 
376 		tp->t_erase = sg->sg_erase;
377 		tp->t_kill = sg->sg_kill;
378 		tp->t_ispeed = sg->sg_ispeed;
379 		tp->t_ospeed = sg->sg_ospeed;
380 		newflags = (tp->t_flags&0xffff0000) | (sg->sg_flags&0xffff);
381 		s = spltty();
382 		if (tp->t_flags&RAW || newflags&RAW || com == TIOCSETP) {
383 			ttywait(tp);
384 			ttyflush(tp, FREAD);
385 		} else if ((tp->t_flags&CBREAK) != (newflags&CBREAK)) {
386 			if (newflags&CBREAK) {
387 				struct clist tq;
388 
389 				catq(&tp->t_rawq, &tp->t_canq);
390 				tq = tp->t_rawq;
391 				tp->t_rawq = tp->t_canq;
392 				tp->t_canq = tq;
393 			} else {
394 				tp->t_flags |= PENDIN;
395 				newflags |= PENDIN;
396 				ttwakeup(tp);
397 			}
398 		}
399 		tp->t_flags = newflags;
400 		if (tp->t_flags&RAW) {
401 			tp->t_state &= ~TS_TTSTOP;
402 			ttstart(tp);
403 		}
404 		splx(s);
405 		break;
406 	}
407 
408 	/* send current parameters to user */
409 	case TIOCGETP: {
410 		register struct sgttyb *sg = (struct sgttyb *)data;
411 
412 		sg->sg_ispeed = tp->t_ispeed;
413 		sg->sg_ospeed = tp->t_ospeed;
414 		sg->sg_erase = tp->t_erase;
415 		sg->sg_kill = tp->t_kill;
416 		sg->sg_flags = tp->t_flags;
417 		break;
418 	}
419 
420 	case FIONBIO:
421 		if (*(int *)data)
422 			tp->t_state |= TS_NBIO;
423 		else
424 			tp->t_state &= ~TS_NBIO;
425 		break;
426 
427 	case FIOASYNC:
428 		if (*(int *)data)
429 			tp->t_state |= TS_ASYNC;
430 		else
431 			tp->t_state &= ~TS_ASYNC;
432 		break;
433 
434 	case TIOCGETC:
435 		bcopy((caddr_t)&tp->t_intrc, data, sizeof (struct tchars));
436 		break;
437 
438 	case TIOCSETC:
439 		bcopy(data, (caddr_t)&tp->t_intrc, sizeof (struct tchars));
440 		break;
441 
442 	/* set/get local special characters */
443 	case TIOCSLTC:
444 		bcopy(data, (caddr_t)&tp->t_suspc, sizeof (struct ltchars));
445 		break;
446 
447 	case TIOCGLTC:
448 		bcopy((caddr_t)&tp->t_suspc, data, sizeof (struct ltchars));
449 		break;
450 
451 	/*
452 	 * Modify local mode word.
453 	 */
454 	case TIOCLBIS:
455 		tp->t_flags |= *(int *)data << 16;
456 		break;
457 
458 	case TIOCLBIC:
459 		tp->t_flags &= ~(*(int *)data << 16);
460 		break;
461 
462 	case TIOCLSET:
463 		tp->t_flags &= 0xffff;
464 		tp->t_flags |= *(int *)data << 16;
465 		break;
466 
467 	case TIOCLGET:
468 		*(int *)data = ((unsigned)tp->t_flags) >> 16;
469 		break;
470 
471 	/*
472 	 * Allow SPGRP only if tty is open for reading.
473 	 * Quick check: if we can find a process in the new pgrp,
474 	 * this user must own that process.
475 	 * SHOULD VERIFY THAT PGRP IS IN USE AND IS THIS USER'S.
476 	 */
477 	case TIOCSPGRP: {
478 		struct proc *p;
479 		int pgrp = *(int *)data;
480 
481 		if (u.u_uid && (flag & FREAD) == 0)
482 			return (EPERM);
483 		p = pfind(pgrp);
484 		if (p && p->p_pgrp == pgrp &&
485 		    p->p_uid != u.u_uid && u.u_uid && !inferior(p))
486 			return (EPERM);
487 		tp->t_pgrp = pgrp;
488 		break;
489 	}
490 
491 	case TIOCGPGRP:
492 		*(int *)data = tp->t_pgrp;
493 		break;
494 
495 	case TIOCSWINSZ:
496 		if (bcmp((caddr_t)&tp->t_winsize, data,
497 		    sizeof (struct winsize))) {
498 			tp->t_winsize = *(struct winsize *)data;
499 			gsignal(tp->t_pgrp, SIGWINCH);
500 		}
501 		break;
502 
503 	case TIOCGWINSZ:
504 		*(struct winsize *)data = tp->t_winsize;
505 		break;
506 
507 	default:
508 		return (-1);
509 	}
510 	return (0);
511 }
512 
513 ttnread(tp)
514 	struct tty *tp;
515 {
516 	int nread = 0;
517 
518 	if (tp->t_flags & PENDIN)
519 		ttypend(tp);
520 	nread = tp->t_canq.c_cc;
521 	if (tp->t_flags & (RAW|CBREAK))
522 		nread += tp->t_rawq.c_cc;
523 	return (nread);
524 }
525 
526 ttselect(dev, rw)
527 	dev_t dev;
528 	int rw;
529 {
530 	register struct tty *tp = &cdevsw[major(dev)].d_ttys[minor(dev)];
531 	int nread;
532 	int s = spltty();
533 
534 	switch (rw) {
535 
536 	case FREAD:
537 		nread = ttnread(tp);
538 		if (nread > 0 || (tp->t_state & TS_CARR_ON) == 0)
539 			goto win;
540 		if (tp->t_rsel && tp->t_rsel->p_wchan == (caddr_t)&selwait)
541 			tp->t_state |= TS_RCOLL;
542 		else
543 			tp->t_rsel = u.u_procp;
544 		break;
545 
546 	case FWRITE:
547 		if (tp->t_outq.c_cc <= TTLOWAT(tp))
548 			goto win;
549 		if (tp->t_wsel && tp->t_wsel->p_wchan == (caddr_t)&selwait)
550 			tp->t_state |= TS_WCOLL;
551 		else
552 			tp->t_wsel = u.u_procp;
553 		break;
554 	}
555 	splx(s);
556 	return (0);
557 win:
558 	splx(s);
559 	return (1);
560 }
561 
562 /*
563  * Initial open of tty, or (re)entry to line discipline.
564  * Establish a process group for distribution of
565  * quits and interrupts from the tty.
566  */
567 ttyopen(dev, tp)
568 	dev_t dev;
569 	register struct tty *tp;
570 {
571 	register struct proc *pp;
572 
573 	pp = u.u_procp;
574 	tp->t_dev = dev;
575 	if (pp->p_pgrp == 0) {
576 		u.u_ttyp = tp;
577 		u.u_ttyd = dev;
578 		if (tp->t_pgrp == 0)
579 			tp->t_pgrp = pp->p_pid;
580 		pp->p_pgrp = tp->t_pgrp;
581 	}
582 	tp->t_state &= ~TS_WOPEN;
583 	if ((tp->t_state & TS_ISOPEN) == 0) {
584 		tp->t_state |= TS_ISOPEN;
585 		bzero((caddr_t)&tp->t_winsize, sizeof(tp->t_winsize));
586 		if (tp->t_line != NTTYDISC)
587 			ttywflush(tp);
588 	}
589 	return (0);
590 }
591 
592 /*
593  * "close" a line discipline
594  */
595 ttylclose(tp)
596 	register struct tty *tp;
597 {
598 
599 	ttywflush(tp);
600 	tp->t_line = 0;
601 }
602 
603 /*
604  * clean tp on last close
605  */
606 ttyclose(tp)
607 	register struct tty *tp;
608 {
609 
610 	ttyflush(tp, FREAD|FWRITE);
611 	tp->t_pgrp = 0;
612 	tp->t_state = 0;
613 }
614 
615 /*
616  * Handle modem control transition on a tty.
617  * Flag indicates new state of carrier.
618  * Returns 0 if the line should be turned off, otherwise 1.
619  */
620 ttymodem(tp, flag)
621 	register struct tty *tp;
622 {
623 
624 	if ((tp->t_state&TS_WOPEN) == 0 && (tp->t_flags & MDMBUF)) {
625 		/*
626 		 * MDMBUF: do flow control according to carrier flag
627 		 */
628 		if (flag) {
629 			tp->t_state &= ~TS_TTSTOP;
630 			ttstart(tp);
631 		} else if ((tp->t_state&TS_TTSTOP) == 0) {
632 			tp->t_state |= TS_TTSTOP;
633 			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
634 		}
635 	} else if (flag == 0) {
636 		/*
637 		 * Lost carrier.
638 		 */
639 		tp->t_state &= ~TS_CARR_ON;
640 		if (tp->t_state & TS_ISOPEN) {
641 			if ((tp->t_flags & NOHANG) == 0) {
642 				gsignal(tp->t_pgrp, SIGHUP);
643 				gsignal(tp->t_pgrp, SIGCONT);
644 				ttyflush(tp, FREAD|FWRITE);
645 				return (0);
646 			}
647 		}
648 	} else {
649 		/*
650 		 * Carrier now on.
651 		 */
652 		tp->t_state |= TS_CARR_ON;
653 		wakeup((caddr_t)&tp->t_rawq);
654 	}
655 	return (1);
656 }
657 
658 /*
659  * Default modem control routine (for other line disciplines).
660  * Return argument flag, to turn off device on carrier drop.
661  */
662 nullmodem(tp, flag)
663 	register struct tty *tp;
664 	int flag;
665 {
666 
667 	if (flag)
668 		tp->t_state |= TS_CARR_ON;
669 	else
670 		tp->t_state &= ~TS_CARR_ON;
671 	return (flag);
672 }
673 
674 /*
675  * reinput pending characters after state switch
676  * call at spltty().
677  */
678 ttypend(tp)
679 	register struct tty *tp;
680 {
681 	struct clist tq;
682 	register c;
683 
684 	tp->t_flags &= ~PENDIN;
685 	tp->t_state |= TS_TYPEN;
686 	tq = tp->t_rawq;
687 	tp->t_rawq.c_cc = 0;
688 	tp->t_rawq.c_cf = tp->t_rawq.c_cl = 0;
689 	while ((c = getc(&tq)) >= 0)
690 		ttyinput(c, tp);
691 	tp->t_state &= ~TS_TYPEN;
692 }
693 
694 /*
695  * Place a character on raw TTY input queue,
696  * putting in delimiters and waking up top
697  * half as needed.  Also echo if required.
698  * The arguments are the character and the
699  * appropriate tty structure.
700  */
701 ttyinput(c, tp)
702 	register c;
703 	register struct tty *tp;
704 {
705 	register int t_flags = tp->t_flags;
706 	int i;
707 
708 	/*
709 	 * If input is pending take it first.
710 	 */
711 	if (t_flags&PENDIN)
712 		ttypend(tp);
713 	tk_nin++;
714 	c &= 0377;
715 
716 	/*
717 	 * In tandem mode, check high water mark.
718 	 */
719 	if (t_flags&TANDEM)
720 		ttyblock(tp);
721 
722 	if (t_flags&RAW) {
723 		/*
724 		 * Raw mode, just put character
725 		 * in input q w/o interpretation.
726 		 */
727 		if (tp->t_rawq.c_cc > TTYHOG)
728 			ttyflush(tp, FREAD|FWRITE);
729 		else {
730 			if (putc(c, &tp->t_rawq) >= 0)
731 				ttwakeup(tp);
732 			ttyecho(c, tp);
733 		}
734 		goto endcase;
735 	}
736 
737 	/*
738 	 * Ignore any high bit added during
739 	 * previous ttyinput processing.
740 	 */
741 	if ((tp->t_state&TS_TYPEN) == 0 && (t_flags&PASS8) == 0)
742 		c &= 0177;
743 	/*
744 	 * Check for literal nexting very first
745 	 */
746 	if (tp->t_state&TS_LNCH) {
747 		c |= 0200;
748 		tp->t_state &= ~TS_LNCH;
749 	}
750 
751 	/*
752 	 * Scan for special characters.  This code
753 	 * is really just a big case statement with
754 	 * non-constant cases.  The bottom of the
755 	 * case statement is labeled ``endcase'', so goto
756 	 * it after a case match, or similar.
757 	 */
758 	if (tp->t_line == NTTYDISC) {
759 		if (c == tp->t_lnextc) {
760 			if (t_flags&ECHO)
761 				ttyout("^\b", tp);
762 			tp->t_state |= TS_LNCH;
763 			goto endcase;
764 		}
765 		if (c == tp->t_flushc) {
766 			if (t_flags&FLUSHO)
767 				tp->t_flags &= ~FLUSHO;
768 			else {
769 				ttyflush(tp, FWRITE);
770 				ttyecho(c, tp);
771 				if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
772 					ttyretype(tp);
773 				tp->t_flags |= FLUSHO;
774 			}
775 			goto startoutput;
776 		}
777 		if (c == tp->t_suspc) {
778 			if ((t_flags&NOFLSH) == 0)
779 				ttyflush(tp, FREAD);
780 			ttyecho(c, tp);
781 			gsignal(tp->t_pgrp, SIGTSTP);
782 			goto endcase;
783 		}
784 	}
785 
786 	/*
787 	 * Handle start/stop characters.
788 	 */
789 	if (c == tp->t_stopc) {
790 		if ((tp->t_state&TS_TTSTOP) == 0) {
791 			tp->t_state |= TS_TTSTOP;
792 			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
793 			return;
794 		}
795 		if (c != tp->t_startc)
796 			return;
797 		goto endcase;
798 	}
799 	if (c == tp->t_startc)
800 		goto restartoutput;
801 
802 	/*
803 	 * Look for interrupt/quit chars.
804 	 */
805 	if (c == tp->t_intrc || c == tp->t_quitc) {
806 		if ((t_flags&NOFLSH) == 0)
807 			ttyflush(tp, FREAD|FWRITE);
808 		ttyecho(c, tp);
809 		gsignal(tp->t_pgrp, c == tp->t_intrc ? SIGINT : SIGQUIT);
810 		goto endcase;
811 	}
812 
813 	if (tp->t_flags & LCASE && c <= 0177) {
814 		if (tp->t_state&TS_BKSL) {
815 			ttyrub(unputc(&tp->t_rawq), tp);
816 			if (maptab[c])
817 				c = maptab[c];
818 			c |= 0200;
819 			tp->t_state &= ~(TS_BKSL|TS_QUOT);
820 		} else if (c >= 'A' && c <= 'Z')
821 			c += 'a' - 'A';
822 		else if (c == '\\')
823 			tp->t_state |= TS_BKSL;
824 	}
825 
826 	/*
827 	 * Cbreak mode, don't process line editing
828 	 * characters; check high water mark for wakeup.
829 	 */
830 	if (t_flags&CBREAK) {
831 		if (tp->t_rawq.c_cc > TTYHOG) {
832 			if (tp->t_outq.c_cc < TTHIWAT(tp) &&
833 			    tp->t_line == NTTYDISC)
834 				(void) ttyoutput(CTRL(g), tp);
835 		} else if (putc(c, &tp->t_rawq) >= 0) {
836 			ttwakeup(tp);
837 			ttyecho(c, tp);
838 		}
839 		goto endcase;
840 	}
841 
842 	/*
843 	 * From here on down cooked mode character
844 	 * processing takes place.
845 	 */
846 	if ((tp->t_state&TS_QUOT) &&
847 	    (c == tp->t_erase || c == tp->t_kill)) {
848 		ttyrub(unputc(&tp->t_rawq), tp);
849 		c |= 0200;
850 	}
851 	if (c == tp->t_erase) {
852 		if (tp->t_rawq.c_cc)
853 			ttyrub(unputc(&tp->t_rawq), tp);
854 		goto endcase;
855 	}
856 	if (c == tp->t_kill) {
857 		if (t_flags&CRTKIL &&
858 		    tp->t_rawq.c_cc == tp->t_rocount) {
859 			while (tp->t_rawq.c_cc)
860 				ttyrub(unputc(&tp->t_rawq), tp);
861 		} else {
862 			ttyecho(c, tp);
863 			ttyecho('\n', tp);
864 			while (getc(&tp->t_rawq) > 0)
865 				;
866 			tp->t_rocount = 0;
867 		}
868 		tp->t_state &= ~TS_LOCAL;
869 		goto endcase;
870 	}
871 
872 	/*
873 	 * New line discipline,
874 	 * check word erase/reprint line.
875 	 */
876 	if (tp->t_line == NTTYDISC) {
877 		if (c == tp->t_werasc) {
878 			if (tp->t_rawq.c_cc == 0)
879 				goto endcase;
880 			do {
881 				c = unputc(&tp->t_rawq);
882 				if (c != ' ' && c != '\t')
883 					goto erasenb;
884 				ttyrub(c, tp);
885 			} while (tp->t_rawq.c_cc);
886 			goto endcase;
887 	erasenb:
888 			do {
889 				ttyrub(c, tp);
890 				if (tp->t_rawq.c_cc == 0)
891 					goto endcase;
892 				c = unputc(&tp->t_rawq);
893 			} while (c != ' ' && c != '\t');
894 			(void) putc(c, &tp->t_rawq);
895 			goto endcase;
896 		}
897 		if (c == tp->t_rprntc) {
898 			ttyretype(tp);
899 			goto endcase;
900 		}
901 	}
902 
903 	/*
904 	 * Check for input buffer overflow
905 	 */
906 	if (tp->t_rawq.c_cc+tp->t_canq.c_cc >= TTYHOG) {
907 		if (tp->t_line == NTTYDISC)
908 			(void) ttyoutput(CTRL(g), tp);
909 		goto endcase;
910 	}
911 
912 	/*
913 	 * Put data char in q for user and
914 	 * wakeup on seeing a line delimiter.
915 	 */
916 	if (putc(c, &tp->t_rawq) >= 0) {
917 		if (ttbreakc(c, tp)) {
918 			tp->t_rocount = 0;
919 			catq(&tp->t_rawq, &tp->t_canq);
920 			ttwakeup(tp);
921 		} else if (tp->t_rocount++ == 0)
922 			tp->t_rocol = tp->t_col;
923 		tp->t_state &= ~TS_QUOT;
924 		if (c == '\\')
925 			tp->t_state |= TS_QUOT;
926 		if (tp->t_state&TS_ERASE) {
927 			tp->t_state &= ~TS_ERASE;
928 			(void) ttyoutput('/', tp);
929 		}
930 		i = tp->t_col;
931 		ttyecho(c, tp);
932 		if (c == tp->t_eofc && t_flags&ECHO) {
933 			i = MIN(2, tp->t_col - i);
934 			while (i > 0) {
935 				(void) ttyoutput('\b', tp);
936 				i--;
937 			}
938 		}
939 	}
940 endcase:
941 	/*
942 	 * If DEC-style start/stop is enabled don't restart
943 	 * output until seeing the start character.
944 	 */
945 	if (t_flags&DECCTQ && tp->t_state&TS_TTSTOP &&
946 	    tp->t_startc != tp->t_stopc)
947 		return;
948 restartoutput:
949 	tp->t_state &= ~TS_TTSTOP;
950 	tp->t_flags &= ~FLUSHO;
951 startoutput:
952 	ttstart(tp);
953 }
954 
955 /*
956  * Put character on TTY output queue, adding delays,
957  * expanding tabs, and handling the CR/NL bit.
958  * This is called both from the top half for output,
959  * and from interrupt level for echoing.
960  * The arguments are the character and the tty structure.
961  * Returns < 0 if putc succeeds, otherwise returns char to resend
962  * Must be recursive.
963  */
964 ttyoutput(c, tp)
965 	register c;
966 	register struct tty *tp;
967 {
968 	register char *colp;
969 	register ctype;
970 
971 	if (tp->t_flags & (RAW|LITOUT)) {
972 		if (tp->t_flags&FLUSHO)
973 			return (-1);
974 		if (putc(c, &tp->t_outq))
975 			return (c);
976 		tk_nout++;
977 		return (-1);
978 	}
979 
980 	/*
981 	 * Ignore EOT in normal mode to avoid
982 	 * hanging up certain terminals.
983 	 */
984 	c &= 0177;
985 	if (c == CEOT && (tp->t_flags&CBREAK) == 0)
986 		return (-1);
987 	/*
988 	 * Turn tabs to spaces as required
989 	 */
990 	if (c == '\t' && (tp->t_flags&TBDELAY) == XTABS) {
991 		register int s;
992 
993 		c = 8 - (tp->t_col&7);
994 		if ((tp->t_flags&FLUSHO) == 0) {
995 			s = spltty();		/* don't interrupt tabs */
996 			c -= b_to_q("        ", c, &tp->t_outq);
997 			tk_nout += c;
998 			splx(s);
999 		}
1000 		tp->t_col += c;
1001 		return (c ? -1 : '\t');
1002 	}
1003 	tk_nout++;
1004 	/*
1005 	 * for upper-case-only terminals,
1006 	 * generate escapes.
1007 	 */
1008 	if (tp->t_flags&LCASE) {
1009 		colp = "({)}!|^~'`";
1010 		while (*colp++)
1011 			if (c == *colp++) {
1012 				if (ttyoutput('\\', tp) >= 0)
1013 					return (c);
1014 				c = colp[-2];
1015 				break;
1016 			}
1017 		if ('A' <= c && c <= 'Z') {
1018 			if (ttyoutput('\\', tp) >= 0)
1019 				return (c);
1020 		} else if ('a' <= c && c <= 'z')
1021 			c += 'A' - 'a';
1022 	}
1023 
1024 	/*
1025 	 * turn <nl> to <cr><lf> if desired.
1026 	 */
1027 	if (c == '\n' && tp->t_flags&CRMOD)
1028 		if (ttyoutput('\r', tp) >= 0)
1029 			return (c);
1030 	if (c == '~' && tp->t_flags&TILDE)
1031 		c = '`';
1032 	if ((tp->t_flags&FLUSHO) == 0 && putc(c, &tp->t_outq))
1033 		return (c);
1034 	/*
1035 	 * Calculate delays.
1036 	 * The numbers here represent clock ticks
1037 	 * and are not necessarily optimal for all terminals.
1038 	 * The delays are indicated by characters above 0200.
1039 	 * In raw mode there are no delays and the
1040 	 * transmission path is 8 bits wide.
1041 	 *
1042 	 * SHOULD JUST ALLOW USER TO SPECIFY DELAYS
1043 	 */
1044 	colp = &tp->t_col;
1045 	ctype = partab[c];
1046 	c = 0;
1047 	switch (ctype&077) {
1048 
1049 	case ORDINARY:
1050 		(*colp)++;
1051 
1052 	case CONTROL:
1053 		break;
1054 
1055 	case BACKSPACE:
1056 		if (*colp)
1057 			(*colp)--;
1058 		break;
1059 
1060 	/*
1061 	 * This macro is close enough to the correct thing;
1062 	 * it should be replaced by real user settable delays
1063 	 * in any event...
1064 	 */
1065 #define	mstohz(ms)	(((ms) * hz) >> 10)
1066 	case NEWLINE:
1067 		ctype = (tp->t_flags >> 8) & 03;
1068 		if (ctype == 1) { /* tty 37 */
1069 			if (*colp > 0) {
1070 				c = (((unsigned)*colp) >> 4) + 3;
1071 				if ((unsigned)c > 6)
1072 					c = 6;
1073 			}
1074 		} else if (ctype == 2) /* vt05 */
1075 			c = mstohz(100);
1076 		*colp = 0;
1077 		break;
1078 
1079 	case TAB:
1080 		ctype = (tp->t_flags >> 10) & 03;
1081 		if (ctype == 1) { /* tty 37 */
1082 			c = 1 - (*colp | ~07);
1083 			if (c < 5)
1084 				c = 0;
1085 		}
1086 		*colp |= 07;
1087 		(*colp)++;
1088 		break;
1089 
1090 	case VTAB:
1091 		if (tp->t_flags&VTDELAY) /* tty 37 */
1092 			c = 0177;
1093 		break;
1094 
1095 	case RETURN:
1096 		ctype = (tp->t_flags >> 12) & 03;
1097 		if (ctype == 1) /* tn 300 */
1098 			c = mstohz(83);
1099 		else if (ctype == 2) /* ti 700 */
1100 			c = mstohz(166);
1101 		else if (ctype == 3) { /* concept 100 */
1102 			int i;
1103 
1104 			if ((i = *colp) >= 0)
1105 				for (; i < 9; i++)
1106 					(void) putc(0177, &tp->t_outq);
1107 		}
1108 		*colp = 0;
1109 	}
1110 	if (c && (tp->t_flags&FLUSHO) == 0)
1111 		(void) putc(c|0200, &tp->t_outq);
1112 	return (-1);
1113 }
1114 #undef mstohz
1115 
1116 /*
1117  * Called from device's read routine after it has
1118  * calculated the tty-structure given as argument.
1119  */
1120 ttread(tp, uio)
1121 	register struct tty *tp;
1122 	struct uio *uio;
1123 {
1124 	register struct clist *qp;
1125 	register c, t_flags;
1126 	int s, first, error = 0;
1127 
1128 loop:
1129 	/*
1130 	 * Take any pending input first.
1131 	 */
1132 	s = spltty();
1133 	if (tp->t_flags&PENDIN)
1134 		ttypend(tp);
1135 	splx(s);
1136 
1137 	if ((tp->t_state&TS_CARR_ON)==0)
1138 		return (EIO);
1139 
1140 	/*
1141 	 * Hang process if it's in the background.
1142 	 */
1143 	if (tp == u.u_ttyp && u.u_procp->p_pgrp != tp->t_pgrp) {
1144 		if ((u.u_procp->p_sigignore & sigmask(SIGTTIN)) ||
1145 		   (u.u_procp->p_sigmask & sigmask(SIGTTIN)) ||
1146 		    u.u_procp->p_flag&SVFORK)
1147 			return (EIO);
1148 		gsignal(u.u_procp->p_pgrp, SIGTTIN);
1149 		sleep((caddr_t)&lbolt, TTIPRI);
1150 		goto loop;
1151 	}
1152 	t_flags = tp->t_flags;
1153 
1154 	/*
1155 	 * In raw mode take characters directly from the
1156 	 * raw queue w/o processing.  Interlock against
1157 	 * device interrupts when interrogating rawq.
1158 	 */
1159 	if (t_flags&RAW) {
1160 		s = spltty();
1161 		if (tp->t_rawq.c_cc <= 0) {
1162 			if ((tp->t_state&TS_CARR_ON) == 0 ||
1163 			    (tp->t_state&TS_NBIO)) {
1164 				splx(s);
1165 				return (EWOULDBLOCK);
1166 			}
1167 			sleep((caddr_t)&tp->t_rawq, TTIPRI);
1168 			splx(s);
1169 			goto loop;
1170 		}
1171 		splx(s);
1172  		while (!error && tp->t_rawq.c_cc && uio->uio_resid)
1173  			error = ureadc(getc(&tp->t_rawq), uio);
1174 		goto checktandem;
1175 	}
1176 
1177 	/*
1178 	 * In cbreak mode use the rawq, otherwise
1179 	 * take characters from the canonicalized q.
1180 	 */
1181 	qp = t_flags&CBREAK ? &tp->t_rawq : &tp->t_canq;
1182 
1183 	/*
1184 	 * No input, sleep on rawq awaiting hardware
1185 	 * receipt and notification.
1186 	 */
1187 	s = spltty();
1188 	if (qp->c_cc <= 0) {
1189 		if ((tp->t_state&TS_CARR_ON) == 0 ||
1190 		    (tp->t_state&TS_NBIO)) {
1191 			splx(s);
1192 			return (EWOULDBLOCK);
1193 		}
1194 		sleep((caddr_t)&tp->t_rawq, TTIPRI);
1195 		splx(s);
1196 		goto loop;
1197 	}
1198 	splx(s);
1199 
1200 	/*
1201 	 * Input present, perform input mapping
1202 	 * and processing (we're not in raw mode).
1203 	 */
1204 	first = 1;
1205 	while ((c = getc(qp)) >= 0) {
1206 		if (t_flags&CRMOD && c == '\r')
1207 			c = '\n';
1208 		/*
1209 		 * Check for delayed suspend character.
1210 		 */
1211 		if (tp->t_line == NTTYDISC && c == tp->t_dsuspc) {
1212 			gsignal(tp->t_pgrp, SIGTSTP);
1213 			if (first) {
1214 				sleep((caddr_t)&lbolt, TTIPRI);
1215 				goto loop;
1216 			}
1217 			break;
1218 		}
1219 		/*
1220 		 * Interpret EOF only in cooked mode.
1221 		 */
1222 		if (c == tp->t_eofc && (t_flags&CBREAK) == 0)
1223 			break;
1224 		/*
1225 		 * Give user character.
1226 		 */
1227  		error = ureadc(t_flags&PASS8 ? c : c & 0177, uio);
1228 		if (error)
1229 			break;
1230  		if (uio->uio_resid == 0)
1231 			break;
1232 		/*
1233 		 * In cooked mode check for a "break character"
1234 		 * marking the end of a "line of input".
1235 		 */
1236 		if ((t_flags&CBREAK) == 0 && ttbreakc(c, tp))
1237 			break;
1238 		first = 0;
1239 	}
1240 
1241 checktandem:
1242 	/*
1243 	 * Look to unblock output now that (presumably)
1244 	 * the input queue has gone down.
1245 	 */
1246 	if (tp->t_state&TS_TBLOCK && tp->t_rawq.c_cc < TTYHOG/5)
1247 		if (putc(tp->t_startc, &tp->t_outq) == 0) {
1248 			tp->t_state &= ~TS_TBLOCK;
1249 			ttstart(tp);
1250 		}
1251 	return (error);
1252 }
1253 
1254 /*
1255  * Check the output queue on tp for space for a kernel message
1256  * (from uprintf/tprintf).  Allow some space over the normal
1257  * hiwater mark so we don't lose messages due to normal flow
1258  * control, but don't let the tty run amok.
1259  */
1260 ttycheckoutq(tp, wait)
1261 	register struct tty *tp;
1262 	int wait;
1263 {
1264 	int hiwat, s;
1265 
1266 	hiwat = TTHIWAT(tp);
1267 	s = spltty();
1268 	if (tp->t_outq.c_cc > hiwat + 200)
1269 		while (tp->t_outq.c_cc > hiwat) {
1270 			ttstart(tp);
1271 			if (wait == 0) {
1272 				splx(s);
1273 				return (0);
1274 			}
1275 			tp->t_state |= TS_ASLEEP;
1276 			sleep((caddr_t)&tp->t_outq, TTOPRI);
1277 		}
1278 	splx(s);
1279 	return (1);
1280 }
1281 
1282 /*
1283  * Called from the device's write routine after it has
1284  * calculated the tty-structure given as argument.
1285  */
1286 ttwrite(tp, uio)
1287 	register struct tty *tp;
1288 	register struct uio *uio;
1289 {
1290 	register char *cp;
1291 	register int cc, ce, c;
1292 	int i, hiwat, cnt, error, s;
1293 	char obuf[OBUFSIZ];
1294 
1295 	hiwat = TTHIWAT(tp);
1296 	cnt = uio->uio_resid;
1297 	error = 0;
1298 loop:
1299 	if ((tp->t_state&TS_CARR_ON) == 0)
1300 		return (EIO);
1301 	/*
1302 	 * Hang the process if it's in the background.
1303 	 */
1304 	if (u.u_procp->p_pgrp != tp->t_pgrp && tp == u.u_ttyp &&
1305 	    (tp->t_flags&TOSTOP) && (u.u_procp->p_flag&SVFORK)==0 &&
1306 	    !(u.u_procp->p_sigignore & sigmask(SIGTTOU)) &&
1307 	    !(u.u_procp->p_sigmask & sigmask(SIGTTOU))) {
1308 		gsignal(u.u_procp->p_pgrp, SIGTTOU);
1309 		sleep((caddr_t)&lbolt, TTIPRI);
1310 		goto loop;
1311 	}
1312 
1313 	/*
1314 	 * Process the user's data in at most OBUFSIZ
1315 	 * chunks.  Perform lower case simulation and
1316 	 * similar hacks.  Keep track of high water
1317 	 * mark, sleep on overflow awaiting device aid
1318 	 * in acquiring new space.
1319 	 */
1320 	while (uio->uio_resid > 0) {
1321 		/*
1322 		 * Grab a hunk of data from the user.
1323 		 */
1324 		cc = uio->uio_iov->iov_len;
1325 		if (cc == 0) {
1326 			uio->uio_iovcnt--;
1327 			uio->uio_iov++;
1328 			if (uio->uio_iovcnt <= 0)
1329 				panic("ttwrite");
1330 			continue;
1331 		}
1332 		if (cc > OBUFSIZ)
1333 			cc = OBUFSIZ;
1334 		cp = obuf;
1335 		error = uiomove(cp, cc, UIO_WRITE, uio);
1336 		if (error)
1337 			break;
1338 		if (tp->t_outq.c_cc > hiwat)
1339 			goto ovhiwat;
1340 		if (tp->t_flags&FLUSHO)
1341 			continue;
1342 		/*
1343 		 * If we're mapping lower case or kludging tildes,
1344 		 * then we've got to look at each character, so
1345 		 * just feed the stuff to ttyoutput...
1346 		 */
1347 		if (tp->t_flags & (LCASE|TILDE)) {
1348 			while (cc > 0) {
1349 				c = *cp++;
1350 				tp->t_rocount = 0;
1351 				while ((c = ttyoutput(c, tp)) >= 0) {
1352 					/* out of clists, wait a bit */
1353 					ttstart(tp);
1354 					sleep((caddr_t)&lbolt, TTOPRI);
1355 					tp->t_rocount = 0;
1356 					if (cc != 0) {
1357 						uio->uio_iov->iov_base -= cc;
1358 						uio->uio_iov->iov_len += cc;
1359 						uio->uio_resid += cc;
1360 						uio->uio_offset -= cc;
1361 					}
1362 					goto loop;
1363 				}
1364 				--cc;
1365 				if (tp->t_outq.c_cc > hiwat)
1366 					goto ovhiwat;
1367 			}
1368 			continue;
1369 		}
1370 		/*
1371 		 * If nothing fancy need be done, grab those characters we
1372 		 * can handle without any of ttyoutput's processing and
1373 		 * just transfer them to the output q.  For those chars
1374 		 * which require special processing (as indicated by the
1375 		 * bits in partab), call ttyoutput.  After processing
1376 		 * a hunk of data, look for FLUSHO so ^O's will take effect
1377 		 * immediately.
1378 		 */
1379 		while (cc > 0) {
1380 			if (tp->t_flags & (RAW|LITOUT))
1381 				ce = cc;
1382 			else {
1383 				ce = cc - scanc((unsigned)cc, (caddr_t)cp,
1384 				   (caddr_t)partab, 077);
1385 				/*
1386 				 * If ce is zero, then we're processing
1387 				 * a special character through ttyoutput.
1388 				 */
1389 				if (ce == 0) {
1390 					tp->t_rocount = 0;
1391 					if (ttyoutput(*cp, tp) >= 0) {
1392 					    /* no c-lists, wait a bit */
1393 					    ttstart(tp);
1394 					    sleep((caddr_t)&lbolt, TTOPRI);
1395 					    if (cc != 0) {
1396 					        uio->uio_iov->iov_base -= cc;
1397 					        uio->uio_iov->iov_len += cc;
1398 					        uio->uio_resid += cc;
1399 						uio->uio_offset -= cc;
1400 					    }
1401 					    goto loop;
1402 					}
1403 					cp++, cc--;
1404 					if (tp->t_flags&FLUSHO ||
1405 					    tp->t_outq.c_cc > hiwat)
1406 						goto ovhiwat;
1407 					continue;
1408 				}
1409 			}
1410 			/*
1411 			 * A bunch of normal characters have been found,
1412 			 * transfer them en masse to the output queue and
1413 			 * continue processing at the top of the loop.
1414 			 * If there are any further characters in this
1415 			 * <= OBUFSIZ chunk, the first should be a character
1416 			 * requiring special handling by ttyoutput.
1417 			 */
1418 			tp->t_rocount = 0;
1419 			i = b_to_q(cp, ce, &tp->t_outq);
1420 			ce -= i;
1421 			tp->t_col += ce;
1422 			cp += ce, cc -= ce, tk_nout += ce;
1423 			if (i > 0) {
1424 				/* out of c-lists, wait a bit */
1425 				ttstart(tp);
1426 				sleep((caddr_t)&lbolt, TTOPRI);
1427 				uio->uio_iov->iov_base -= cc;
1428 				uio->uio_iov->iov_len += cc;
1429 				uio->uio_resid += cc;
1430 				uio->uio_offset -= cc;
1431 				goto loop;
1432 			}
1433 			if (tp->t_flags&FLUSHO || tp->t_outq.c_cc > hiwat)
1434 				goto ovhiwat;
1435 		}
1436 	}
1437 	ttstart(tp);
1438 	return (error);
1439 
1440 ovhiwat:
1441 	s = spltty();
1442 	if (cc != 0) {
1443 		uio->uio_iov->iov_base -= cc;
1444 		uio->uio_iov->iov_len += cc;
1445 		uio->uio_resid += cc;
1446 		uio->uio_offset -= cc;
1447 	}
1448 	/*
1449 	 * This can only occur if FLUSHO
1450 	 * is also set in t_flags.
1451 	 */
1452 	if (tp->t_outq.c_cc <= hiwat) {
1453 		splx(s);
1454 		goto loop;
1455 	}
1456 	ttstart(tp);
1457 	if (tp->t_state&TS_NBIO) {
1458 		splx(s);
1459 		if (uio->uio_resid == cnt)
1460 			return (EWOULDBLOCK);
1461 		return (0);
1462 	}
1463 	tp->t_state |= TS_ASLEEP;
1464 	sleep((caddr_t)&tp->t_outq, TTOPRI);
1465 	splx(s);
1466 	goto loop;
1467 }
1468 
1469 /*
1470  * Rubout one character from the rawq of tp
1471  * as cleanly as possible.
1472  */
1473 ttyrub(c, tp)
1474 	register c;
1475 	register struct tty *tp;
1476 {
1477 	register char *cp;
1478 	register int savecol;
1479 	int s;
1480 	char *nextc();
1481 
1482 	if ((tp->t_flags&ECHO) == 0)
1483 		return;
1484 	tp->t_flags &= ~FLUSHO;
1485 	c &= 0377;
1486 	if (tp->t_flags&CRTBS) {
1487 		if (tp->t_rocount == 0) {
1488 			/*
1489 			 * Screwed by ttwrite; retype
1490 			 */
1491 			ttyretype(tp);
1492 			return;
1493 		}
1494 		if (c == ('\t'|0200) || c == ('\n'|0200))
1495 			ttyrubo(tp, 2);
1496 		else switch (partab[c&=0177]&0177) {
1497 
1498 		case ORDINARY:
1499 			if (tp->t_flags&LCASE && c >= 'A' && c <= 'Z')
1500 				ttyrubo(tp, 2);
1501 			else
1502 				ttyrubo(tp, 1);
1503 			break;
1504 
1505 		case VTAB:
1506 		case BACKSPACE:
1507 		case CONTROL:
1508 		case RETURN:
1509 			if (tp->t_flags&CTLECH)
1510 				ttyrubo(tp, 2);
1511 			break;
1512 
1513 		case TAB:
1514 			if (tp->t_rocount < tp->t_rawq.c_cc) {
1515 				ttyretype(tp);
1516 				return;
1517 			}
1518 			s = spltty();
1519 			savecol = tp->t_col;
1520 			tp->t_state |= TS_CNTTB;
1521 			tp->t_flags |= FLUSHO;
1522 			tp->t_col = tp->t_rocol;
1523 			cp = tp->t_rawq.c_cf;
1524 			for (; cp; cp = nextc(&tp->t_rawq, cp))
1525 				ttyecho(*cp, tp);
1526 			tp->t_flags &= ~FLUSHO;
1527 			tp->t_state &= ~TS_CNTTB;
1528 			splx(s);
1529 			/*
1530 			 * savecol will now be length of the tab
1531 			 */
1532 			savecol -= tp->t_col;
1533 			tp->t_col += savecol;
1534 			if (savecol > 8)
1535 				savecol = 8;		/* overflow screw */
1536 			while (--savecol >= 0)
1537 				(void) ttyoutput('\b', tp);
1538 			break;
1539 
1540 		default:
1541 			panic("ttyrub");
1542 		}
1543 	} else if (tp->t_flags&PRTERA) {
1544 		if ((tp->t_state&TS_ERASE) == 0) {
1545 			(void) ttyoutput('\\', tp);
1546 			tp->t_state |= TS_ERASE;
1547 		}
1548 		ttyecho(c, tp);
1549 	} else
1550 		ttyecho(tp->t_erase, tp);
1551 	tp->t_rocount--;
1552 }
1553 
1554 /*
1555  * Crt back over cnt chars perhaps
1556  * erasing them.
1557  */
1558 ttyrubo(tp, cnt)
1559 	register struct tty *tp;
1560 	int cnt;
1561 {
1562 	register char *rubostring = tp->t_flags&CRTERA ? "\b \b" : "\b";
1563 
1564 	while (--cnt >= 0)
1565 		ttyout(rubostring, tp);
1566 }
1567 
1568 /*
1569  * Reprint the rawq line.
1570  * We assume c_cc has already been checked.
1571  */
1572 ttyretype(tp)
1573 	register struct tty *tp;
1574 {
1575 	register char *cp;
1576 	char *nextc();
1577 	int s;
1578 
1579 	if (tp->t_rprntc != 0377)
1580 		ttyecho(tp->t_rprntc, tp);
1581 	(void) ttyoutput('\n', tp);
1582 	s = spltty();
1583 	for (cp = tp->t_canq.c_cf; cp; cp = nextc(&tp->t_canq, cp))
1584 		ttyecho(*cp, tp);
1585 	for (cp = tp->t_rawq.c_cf; cp; cp = nextc(&tp->t_rawq, cp))
1586 		ttyecho(*cp, tp);
1587 	tp->t_state &= ~TS_ERASE;
1588 	splx(s);
1589 	tp->t_rocount = tp->t_rawq.c_cc;
1590 	tp->t_rocol = 0;
1591 }
1592 
1593 /*
1594  * Echo a typed character to the terminal
1595  */
1596 ttyecho(c, tp)
1597 	register c;
1598 	register struct tty *tp;
1599 {
1600 
1601 	if ((tp->t_state&TS_CNTTB) == 0)
1602 		tp->t_flags &= ~FLUSHO;
1603 	if ((tp->t_flags&ECHO) == 0)
1604 		return;
1605 	c &= 0377;
1606 	if (tp->t_flags&RAW) {
1607 		(void) ttyoutput(c, tp);
1608 		return;
1609 	}
1610 	if (c == '\r' && tp->t_flags&CRMOD)
1611 		c = '\n';
1612 	if (tp->t_flags&CTLECH) {
1613 		if ((c&0177) <= 037 && c!='\t' && c!='\n' || (c&0177)==0177) {
1614 			(void) ttyoutput('^', tp);
1615 			c &= 0177;
1616 			if (c == 0177)
1617 				c = '?';
1618 			else if (tp->t_flags&LCASE)
1619 				c += 'a' - 1;
1620 			else
1621 				c += 'A' - 1;
1622 		}
1623 	}
1624 	(void) ttyoutput(c&0177, tp);
1625 }
1626 
1627 /*
1628  * Is c a break char for tp?
1629  */
1630 ttbreakc(c, tp)
1631 	register c;
1632 	register struct tty *tp;
1633 {
1634 	return (c == '\n' || c == tp->t_eofc || c == tp->t_brkc ||
1635 		c == '\r' && (tp->t_flags&CRMOD));
1636 }
1637 
1638 /*
1639  * send string cp to tp
1640  */
1641 ttyout(cp, tp)
1642 	register char *cp;
1643 	register struct tty *tp;
1644 {
1645 	register char c;
1646 
1647 	while (c = *cp++)
1648 		(void) ttyoutput(c, tp);
1649 }
1650 
1651 ttwakeup(tp)
1652 	struct tty *tp;
1653 {
1654 
1655 	if (tp->t_rsel) {
1656 		selwakeup(tp->t_rsel, tp->t_state&TS_RCOLL);
1657 		tp->t_state &= ~TS_RCOLL;
1658 		tp->t_rsel = 0;
1659 	}
1660 	if (tp->t_state & TS_ASYNC)
1661 		gsignal(tp->t_pgrp, SIGIO);
1662 	wakeup((caddr_t)&tp->t_rawq);
1663 }
1664