xref: /csrg-svn/sys/kern/tty.c (revision 43092)
1 /*
2  * Copyright (c) 1982, 1986, 1990 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	7.29 (Berkeley) 06/14/90
7  */
8 
9 #include "param.h"
10 #include "systm.h"
11 #include "user.h"
12 #include "ioctl.h"
13 #define TTYDEFCHARS
14 #include "tty.h"
15 #undef TTYDEFCHARS
16 #include "proc.h"
17 #include "file.h"
18 #include "conf.h"
19 #include "dkstat.h"
20 #include "uio.h"
21 #include "kernel.h"
22 #include "vnode.h"
23 #include "syslog.h"
24 
25 #include "machine/reg.h"
26 
27 /* symbolic sleep message strings */
28 char ttyin[] = "ttyin";
29 char ttyout[] = "ttyout";
30 char ttopen[] = "ttyopn";
31 char ttclos[] = "ttycls";
32 char ttybg[] = "ttybg";
33 char ttybuf[] = "ttybuf";
34 
35 /*
36  * Table giving parity for characters and indicating
37  * character classes to tty driver. The 8th bit
38  * indicates parity, the 7th bit indicates the character
39  * is an alphameric or underscore (for ALTWERASE), and the
40  * low 6 bits indicate delay type.  If the low 6 bits are 0
41  * then the character needs no special processing on output.
42  */
43 
44 char partab[] = {
45 	0001,0201,0201,0001,0201,0001,0001,0201,	/* nul - bel */
46 	0202,0004,0003,0201,0005,0206,0201,0001,	/* bs - si */
47 	0201,0001,0001,0201,0001,0201,0201,0001,	/* dle - etb */
48 	0001,0201,0201,0001,0201,0001,0001,0201,	/* can - us */
49 	0200,0000,0000,0200,0000,0200,0200,0000,	/* sp - ' */
50 	0000,0200,0200,0000,0200,0000,0000,0200,	/* ( - / */
51 	0100,0300,0300,0100,0300,0100,0100,0300,	/* 0 - 7 */
52 	0300,0100,0000,0200,0000,0200,0200,0000,	/* 8 - ? */
53 	0200,0100,0100,0300,0100,0300,0300,0100,	/* @ - G */
54 	0100,0300,0300,0100,0300,0100,0100,0300,	/* H - O */
55 	0100,0300,0300,0100,0300,0100,0100,0300,	/* P - W */
56 	0300,0100,0100,0200,0000,0200,0200,0300,	/* X - _ */
57 	0000,0300,0300,0100,0300,0100,0100,0300,	/* ` - g */
58 	0300,0100,0100,0300,0100,0300,0300,0100,	/* h - o */
59 	0300,0100,0100,0300,0100,0300,0300,0100,	/* p - w */
60 	0100,0300,0300,0000,0200,0000,0000,0201,	/* x - del */
61 	/*
62 	 * meta chars
63 	 */
64 	0001,0201,0201,0001,0201,0001,0001,0201,	/* nul - bel */
65 	0202,0004,0003,0201,0005,0206,0201,0001,	/* bs - si */
66 	0201,0001,0001,0201,0001,0201,0201,0001,	/* dle - etb */
67 	0001,0201,0201,0001,0201,0001,0001,0201,	/* can - us */
68 	0200,0000,0000,0200,0000,0200,0200,0000,	/* sp - ' */
69 	0000,0200,0200,0000,0200,0000,0000,0200,	/* ( - / */
70 	0100,0300,0300,0100,0300,0100,0100,0300,	/* 0 - 7 */
71 	0300,0100,0000,0200,0000,0200,0200,0000,	/* 8 - ? */
72 	0200,0100,0100,0300,0100,0300,0300,0100,	/* @ - G */
73 	0100,0300,0300,0100,0300,0100,0100,0300,	/* H - O */
74 	0100,0300,0300,0100,0300,0100,0100,0300,	/* P - W */
75 	0300,0100,0100,0200,0000,0200,0200,0300,	/* X - _ */
76 	0000,0300,0300,0100,0300,0100,0100,0300,	/* ` - g */
77 	0300,0100,0100,0300,0100,0300,0300,0100,	/* h - o */
78 	0300,0100,0100,0300,0100,0300,0300,0100,	/* p - w */
79 	0100,0300,0300,0000,0200,0000,0000,0201,	/* x - del */
80 };
81 
82 extern struct tty *constty;		/* temporary virtual console */
83 extern char partab[], maptab[];
84 
85 /*
86  * Is 'c' a line delimiter ("break" character)?
87  */
88 #define ttbreakc(c) ((c) == '\n' || ((c) == cc[VEOF] || \
89 	(c) == cc[VEOL] || (c) == cc[VEOL2]) && (c) != _POSIX_VDISABLE)
90 
91 ttychars(tp)
92 	struct tty *tp;
93 {
94 	bcopy(ttydefchars, tp->t_cc, sizeof(ttydefchars));
95 }
96 
97 /*
98  * Wait for output to drain, then flush input waiting.
99  */
100 ttywflush(tp)
101 	struct tty *tp;
102 {
103 	int error;
104 
105 	if ((error = ttywait(tp)) == 0)
106 		ttyflush(tp, FREAD);
107 	return (error);
108 }
109 
110 /*
111  * Wait for output to drain.
112  */
113 ttywait(tp)
114 	register struct tty *tp;
115 {
116 	int error = 0, s = spltty();
117 
118 	while ((tp->t_outq.c_cc || tp->t_state&TS_BUSY) &&
119 	    (tp->t_state&TS_CARR_ON || tp->t_cflag&CLOCAL) &&
120 	    tp->t_oproc) {
121 		(*tp->t_oproc)(tp);
122 		tp->t_state |= TS_ASLEEP;
123 		if ((error = tsleep((caddr_t)&tp->t_outq, TTOPRI | PCATCH,
124 				    ttyout, 0)) ||
125 		    (error = ttclosed(tp)))
126 			break;
127 	}
128 	splx(s);
129 	return (error);
130 }
131 
132 /*
133  * Flush all TTY queues
134  */
135 ttyflush(tp, rw)
136 	register struct tty *tp;
137 {
138 	register s;
139 
140 	s = spltty();
141 	if (rw & FREAD) {
142 		while (getc(&tp->t_canq) >= 0)
143 			;
144 		ttwakeup(tp);
145 	}
146 	if (rw & FWRITE) {
147 		wakeup((caddr_t)&tp->t_outq); /* XXX? what about selwakeup? */
148 		tp->t_state &= ~TS_TTSTOP;
149 		(*cdevsw[major(tp->t_dev)].d_stop)(tp, rw);
150 		while (getc(&tp->t_outq) >= 0)
151 			;
152 	}
153 	if (rw & FREAD) {
154 		while (getc(&tp->t_rawq) >= 0)
155 			;
156 		tp->t_rocount = 0;
157 		tp->t_rocol = 0;
158 		tp->t_state &= ~TS_LOCAL;
159 	}
160 	splx(s);
161 }
162 
163 /*
164  * Send stop character on input overflow.
165  */
166 ttyblock(tp)
167 	register struct tty *tp;
168 {
169 	register x;
170 
171 	x = tp->t_rawq.c_cc + tp->t_canq.c_cc;
172 	if (tp->t_rawq.c_cc > TTYHOG) {
173 		ttyflush(tp, FREAD|FWRITE);
174 		tp->t_state &= ~TS_TBLOCK;
175 	}
176 	/*
177 	 * Block further input iff:
178 	 * Current input > threshold AND input is available to user program
179 	 */
180 	if (x >= TTYHOG/2 && (tp->t_state & TS_TBLOCK) == 0 &&
181 	    ((tp->t_lflag&ICANON) == 0) || (tp->t_canq.c_cc > 0) &&
182 	    tp->t_cc[VSTOP] != _POSIX_VDISABLE) {
183 		if (putc(tp->t_cc[VSTOP], &tp->t_outq) == 0) {
184 			tp->t_state |= TS_TBLOCK;
185 			ttstart(tp);
186 		}
187 	}
188 }
189 
190 /*
191  * Restart typewriter output following a delay
192  * timeout.
193  * The name of the routine is passed to the timeout
194  * subroutine and it is called during a clock interrupt.
195  */
196 ttrstrt(tp)
197 	struct tty *tp;
198 {
199 
200 #ifdef DIAGNOSTIC
201 	if (tp == 0)
202 		panic("ttrstrt");
203 #endif
204 	tp->t_state &= ~TS_TIMEOUT;
205 	ttstart(tp);
206 }
207 
208 /*
209  * Start output on the typewriter. It is used from the top half
210  * after some characters have been put on the output queue,
211  * from the interrupt routine to transmit the next
212  * character, and after a timeout has finished.
213  */
214 ttstart(tp)
215 	struct tty *tp;
216 {
217 
218 	if (tp->t_oproc)		/* kludge for pty */
219 		(*tp->t_oproc)(tp);
220 }
221 
222 /*
223  * Common code for tty ioctls.
224  */
225 /*ARGSUSED*/
226 ttioctl(tp, com, data, flag)
227 	register struct tty *tp;
228 	caddr_t data;
229 {
230 	extern int nldisp;
231 	int s, error;
232 
233 	/*
234 	 * If the ioctl involves modification,
235 	 * hang if in the background.
236 	 */
237 	switch (com) {
238 
239 	case TIOCSETD:
240 	case TIOCFLUSH:
241 	/*case TIOCSPGRP:*/
242 	case TIOCSTI:
243 	case TIOCSWINSZ:
244 	case TIOCSETA:
245 	case TIOCSETAW:
246 	case TIOCSETAF:
247 /**** these get removed ****
248 	case TIOCSETAS:
249 	case TIOCSETAWS:
250 	case TIOCSETAFS:
251 /***************************/
252 #ifdef COMPAT_43
253 	case TIOCSETP:
254 	case TIOCSETN:
255 	case TIOCSETC:
256 	case TIOCSLTC:
257 	case TIOCLBIS:
258 	case TIOCLBIC:
259 	case TIOCLSET:
260 	case OTIOCSETD:
261 #endif
262 		while (isbackground(u.u_procp, tp) &&
263 		   u.u_procp->p_pgrp->pg_jobc &&
264 		   (u.u_procp->p_flag&SVFORK) == 0 &&
265 		   (u.u_procp->p_sigignore & sigmask(SIGTTOU)) == 0 &&
266 		   (u.u_procp->p_sigmask & sigmask(SIGTTOU)) == 0) {
267 			pgsignal(u.u_procp->p_pgrp, SIGTTOU, 1);
268 			if ((error = tsleep((caddr_t)&lbolt, TTOPRI | PCATCH,
269 					    ttybg, 0)) ||
270 			    (error = ttclosed(tp)))
271 				return (error);
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 		dev_t dev = tp->t_dev;
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 	case TIOCHPCL:
318 		tp->t_cflag |= HUPCL;
319 		break;
320 
321 	case TIOCFLUSH: {
322 		register int flags = *(int *)data;
323 
324 		if (flags == 0)
325 			flags = FREAD|FWRITE;
326 		else
327 			flags &= FREAD|FWRITE;
328 		ttyflush(tp, flags);
329 		break;
330 	}
331 
332 	case FIOASYNC:
333 		if (*(int *)data)
334 			tp->t_state |= TS_ASYNC;
335 		else
336 			tp->t_state &= ~TS_ASYNC;
337 		break;
338 
339 	case FIONBIO:
340 		break;	/* XXX remove */
341 
342 	/* return number of characters immediately available */
343 	case FIONREAD:
344 		*(off_t *)data = ttnread(tp);
345 		break;
346 
347 	case TIOCOUTQ:
348 		*(int *)data = tp->t_outq.c_cc;
349 		break;
350 
351 	case TIOCSTOP:
352 		s = spltty();
353 		if ((tp->t_state&TS_TTSTOP) == 0) {
354 			tp->t_state |= TS_TTSTOP;
355 			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
356 		}
357 		splx(s);
358 		break;
359 
360 	case TIOCSTART:
361 		s = spltty();
362 		if ((tp->t_state&TS_TTSTOP) || (tp->t_lflag&FLUSHO)) {
363 			tp->t_state &= ~TS_TTSTOP;
364 			tp->t_lflag &= ~FLUSHO;
365 			ttstart(tp);
366 		}
367 		splx(s);
368 		break;
369 
370 	/*
371 	 * Simulate typing of a character at the terminal.
372 	 */
373 	case TIOCSTI:
374 		if (u.u_uid && (flag & FREAD) == 0)
375 			return (EPERM);
376 		if (u.u_uid && !isctty(u.u_procp, tp))
377 			return (EACCES);
378 		(*linesw[tp->t_line].l_rint)(*(char *)data, tp);
379 		break;
380 
381 	case TIOCGETA: {
382 		struct termios *t = (struct termios *)data;
383 
384 		bcopy(&tp->t_termios, t, sizeof(struct termios));
385 		break;
386 	}
387 
388 	/*** THIS ALL GETS REMOVED ***/
389 	case JUNK_TIOCSETAS:
390 	case JUNK_TIOCSETAWS:
391 	case JUNK_TIOCSETAFS:
392 		((struct termios *)data)->c_cflag |= CIGNORE;
393 		switch(com) {
394 		case JUNK_TIOCSETAS:
395 			com = TIOCSETA;
396 			break;
397 		case JUNK_TIOCSETAWS:
398 			com = TIOCSETAW;
399 			break;
400 		case JUNK_TIOCSETAFS:
401 			com = TIOCSETAF;
402 			break;
403 		}
404 	/*******************************/
405 		/*FALLTHROGH*/
406 	case TIOCSETA:
407 	case TIOCSETAW:
408 	case TIOCSETAF: {
409 		register struct termios *t = (struct termios *)data;
410 
411 		s = spltty();
412 		if (com == TIOCSETAW || com == TIOCSETAF) {
413 			if (error = ttywait(tp)) {
414 				splx(s);
415 				return (error);
416 			}
417 			if (com == TIOCSETAF);
418 				ttyflush(tp, FREAD);
419 		}
420 		if ((t->c_cflag&CIGNORE) == 0) {
421 			/*
422 			 * set device hardware
423 			 */
424 			if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
425 				splx(s);
426 				return (error);
427 			} else {
428 				if ((tp->t_state&TS_CARR_ON) == 0 &&
429 				    (tp->t_cflag&CLOCAL) &&
430 				    (t->c_cflag&CLOCAL) == 0) {
431 					tp->t_state &= ~TS_ISOPEN;
432 					tp->t_state |= TS_WOPEN;
433 					ttwakeup(tp);
434 				}
435 				tp->t_cflag = t->c_cflag;
436 				tp->t_ispeed = t->c_ispeed;
437 				tp->t_ospeed = t->c_ospeed;
438 			}
439 			ttsetwater(tp);
440 		}
441 		if (com != TIOCSETAF) {
442 			if ((t->c_lflag&ICANON) != (tp->t_lflag&ICANON))
443 				if (t->c_lflag&ICANON) {
444 					tp->t_lflag |= PENDIN;
445 					ttwakeup(tp);
446 				}
447 				else {
448 					struct clist tq;
449 
450 					catq(&tp->t_rawq, &tp->t_canq);
451 					tq = tp->t_rawq;
452 					tp->t_rawq = tp->t_canq;
453 					tp->t_canq = tq;
454 				}
455 		}
456 		tp->t_iflag = t->c_iflag;
457 		tp->t_oflag = t->c_oflag;
458 		/*
459 		 * Make the EXTPROC bit read only.
460 		 */
461 		if (tp->t_lflag&EXTPROC)
462 			t->c_lflag |= EXTPROC;
463 		else
464 			t->c_lflag &= ~EXTPROC;
465 		tp->t_lflag = t->c_lflag;
466 		bcopy(t->c_cc, tp->t_cc, sizeof(t->c_cc));
467 		splx(s);
468 		break;
469 	}
470 
471 	/*
472 	 * Set controlling terminal.
473 	 * Session ctty vnode pointer set in vnode layer.
474 	 */
475 	case TIOCSCTTY: {
476 		register struct proc *p = u.u_procp;
477 
478 		if (!SESS_LEADER(p) ||
479 		   (p->p_session->s_ttyvp || tp->t_session) &&
480 		   (tp->t_session != p->p_session))
481 			return (EPERM);
482 		tp->t_session = p->p_session;
483 		tp->t_pgrp = p->p_pgrp;
484 		p->p_session->s_ttyp = tp;
485 		p->p_flag |= SCTTY;
486 		break;
487 	}
488 
489 	/*
490 	 * Set terminal process group.
491 	 */
492 	case TIOCSPGRP: {
493 		register struct proc *p = u.u_procp;
494 		register struct pgrp *pgrp = pgfind(*(int *)data);
495 
496 		if (!isctty(p, tp))
497 			return (ENOTTY);
498 		else if (pgrp == NULL || pgrp->pg_session != p->p_session)
499 			return (EPERM);
500 		tp->t_pgrp = pgrp;
501 		break;
502 	}
503 
504 	case TIOCGPGRP:
505 		if (!isctty(u.u_procp, tp))
506 			return (ENOTTY);
507 		*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
508 		break;
509 
510 	case TIOCSWINSZ:
511 		if (bcmp((caddr_t)&tp->t_winsize, data,
512 		    sizeof (struct winsize))) {
513 			tp->t_winsize = *(struct winsize *)data;
514 			pgsignal(tp->t_pgrp, SIGWINCH, 1);
515 		}
516 		break;
517 
518 	case TIOCGWINSZ:
519 		*(struct winsize *)data = tp->t_winsize;
520 		break;
521 
522 	case TIOCCONS:
523 		if (*(int *)data) {
524 			if (constty && constty != tp &&
525 			    (constty->t_state & (TS_CARR_ON|TS_ISOPEN)) ==
526 			    (TS_CARR_ON|TS_ISOPEN))
527 				return (EBUSY);
528 #ifndef	UCONSOLE
529 			if (error = suser(u.u_cred, &u.u_acflag))
530 				return (error);
531 #endif
532 			constty = tp;
533 		} else if (tp == constty)
534 			constty = NULL;
535 		break;
536 
537 #ifdef COMPAT_43
538 	case TIOCGETP:
539 	case TIOCSETP:
540 	case TIOCSETN:
541 	case TIOCGETC:
542 	case TIOCSETC:
543 	case TIOCSLTC:
544 	case TIOCGLTC:
545 	case TIOCLBIS:
546 	case TIOCLBIC:
547 	case TIOCLSET:
548 	case TIOCLGET:
549 	case OTIOCGETD:
550 	case OTIOCSETD:
551 		return(ttcompat(tp, com, data, flag));
552 #endif
553 
554 	default:
555 		return (-1);
556 	}
557 	return (0);
558 }
559 
560 ttnread(tp)
561 	struct tty *tp;
562 {
563 	int nread = 0;
564 
565 	if (tp->t_lflag & PENDIN)
566 		ttypend(tp);
567 	nread = tp->t_canq.c_cc;
568 	if ((tp->t_lflag & ICANON) == 0)
569 		nread += tp->t_rawq.c_cc;
570 	return (nread);
571 }
572 
573 ttselect(dev, rw)
574 	dev_t dev;
575 	int rw;
576 {
577 	register struct tty *tp = &cdevsw[major(dev)].d_ttys[minor(dev)];
578 	int nread;
579 	int s = spltty();
580 
581 	switch (rw) {
582 
583 	case FREAD:
584 		nread = ttnread(tp);
585 		if (nread > 0 ||
586 		   ((tp->t_cflag&CLOCAL) == 0 && (tp->t_state&TS_CARR_ON) == 0))
587 			goto win;
588 		if (tp->t_rsel && tp->t_rsel->p_wchan == (caddr_t)&selwait)
589 			tp->t_state |= TS_RCOLL;
590 		else
591 			tp->t_rsel = u.u_procp;
592 		break;
593 
594 	case FWRITE:
595 		if (tp->t_outq.c_cc <= tp->t_lowat)
596 			goto win;
597 		if (tp->t_wsel && tp->t_wsel->p_wchan == (caddr_t)&selwait)
598 			tp->t_state |= TS_WCOLL;
599 		else
600 			tp->t_wsel = u.u_procp;
601 		break;
602 	}
603 	splx(s);
604 	return (0);
605 win:
606 	splx(s);
607 	return (1);
608 }
609 
610 /*
611  * Initial open of tty, or (re)entry to line discipline.
612  */
613 ttyopen(dev, tp)
614 	dev_t dev;
615 	register struct tty *tp;
616 {
617 
618 	tp->t_dev = dev;
619 
620 	if (ttclosed(tp))	/* XXX is this still needed? (drivers do it) */
621 		return (ERESTART);
622 	tp->t_state &= ~TS_WOPEN;
623 	if ((tp->t_state & TS_ISOPEN) == 0) {
624 		tp->t_state |= TS_ISOPEN;
625 		bzero((caddr_t)&tp->t_winsize, sizeof(tp->t_winsize));
626 	}
627 	return (0);
628 }
629 
630 /*
631  * "close" a line discipline
632  */
633 ttylclose(tp)
634 	register struct tty *tp;
635 {
636 
637 	ttywflush(tp);
638 }
639 
640 /*
641  * clean tp on last close
642  */
643 ttyclose(tp)
644 	register struct tty *tp;
645 {
646 	if (constty == tp)
647 		constty = NULL;
648 	ttyflush(tp, FREAD|FWRITE);
649 	tp->t_session = NULL;
650 	tp->t_pgrp = NULL;
651 	tp->t_state = 0;
652 	return (0);
653 }
654 
655 /*
656  * Handle modem control transition on a tty.
657  * Flag indicates new state of carrier.
658  * Returns 0 if the line should be turned off, otherwise 1.
659  */
660 ttymodem(tp, flag)
661 	register struct tty *tp;
662 {
663 
664 	if ((tp->t_state&TS_WOPEN) == 0 && (tp->t_lflag&MDMBUF)) {
665 		/*
666 		 * MDMBUF: do flow control according to carrier flag
667 		 */
668 		if (flag) {
669 			tp->t_state &= ~TS_TTSTOP;
670 			ttstart(tp);
671 		} else if ((tp->t_state&TS_TTSTOP) == 0) {
672 			tp->t_state |= TS_TTSTOP;
673 			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
674 		}
675 	} else if (flag == 0) {
676 		/*
677 		 * Lost carrier.
678 		 */
679 		tp->t_state &= ~TS_CARR_ON;
680 		if (tp->t_state&TS_ISOPEN && (tp->t_cflag&CLOCAL) == 0) {
681 			if (tp->t_session && tp->t_session->s_leader)
682 				psignal(tp->t_session->s_leader, SIGHUP);
683 			ttyflush(tp, FREAD|FWRITE);
684 			return (0);
685 		}
686 	} else {
687 		/*
688 		 * Carrier now on.
689 		 */
690 		tp->t_state |= TS_CARR_ON;
691 		ttwakeup(tp);
692 	}
693 	return (1);
694 }
695 
696 /*
697  * Default modem control routine (for other line disciplines).
698  * Return argument flag, to turn off device on carrier drop.
699  */
700 nullmodem(tp, flag)
701 	register struct tty *tp;
702 	int flag;
703 {
704 
705 	if (flag)
706 		tp->t_state |= TS_CARR_ON;
707 	else {
708 		tp->t_state &= ~TS_CARR_ON;
709 		if ((tp->t_cflag&CLOCAL) == 0) {
710 			if (tp->t_session && tp->t_session->s_leader)
711 				psignal(tp->t_session->s_leader, SIGHUP);
712 			return (0);
713 		}
714 	}
715 	return (1);
716 }
717 
718 /*
719  * reinput pending characters after state switch
720  * call at spltty().
721  */
722 ttypend(tp)
723 	register struct tty *tp;
724 {
725 	struct clist tq;
726 	register c;
727 
728 	tp->t_lflag &= ~PENDIN;
729 	tp->t_state |= TS_TYPEN;
730 	tq = tp->t_rawq;
731 	tp->t_rawq.c_cc = 0;
732 	tp->t_rawq.c_cf = tp->t_rawq.c_cl = 0;
733 	while ((c = getc(&tq)) >= 0)
734 		ttyinput(c, tp);
735 	tp->t_state &= ~TS_TYPEN;
736 }
737 
738 /*
739  *
740  * Place a character on raw TTY input queue,
741  * putting in delimiters and waking up top
742  * half as needed.  Also echo if required.
743  * The arguments are the character and the
744  * appropriate tty structure.
745  */
746 ttyinput(c, tp)
747 	register c;
748 	register struct tty *tp;
749 {
750 	register int iflag = tp->t_iflag;
751 	register int lflag = tp->t_lflag;
752 	register u_char *cc = tp->t_cc;
753 	int i, err;
754 
755 	/*
756 	 * If input is pending take it first.
757 	 */
758 	if (lflag&PENDIN)
759 		ttypend(tp);
760 	/*
761 	 * Gather stats.
762 	 */
763 	tk_nin++;
764 	if (lflag&ICANON) {
765 		tk_cancc++;
766 		tp->t_cancc++;
767 	} else {
768 		tk_rawcc++;
769 		tp->t_rawcc++;
770 	}
771 	/*
772 	 * Handle exceptional conditions (break, parity, framing).
773 	 */
774 	if (err = (c&TTY_ERRORMASK)) {
775 		c &= ~TTY_ERRORMASK;
776 		if (err&TTY_FE && !c) {		/* break */
777 			if (iflag&IGNBRK)
778 				goto endcase;
779 			else if (iflag&BRKINT && lflag&ISIG &&
780 				(cc[VINTR] != _POSIX_VDISABLE))
781 				c = cc[VINTR];
782 			else {
783 				c = 0;
784 				if (iflag&PARMRK)
785 					goto parmrk;
786 			}
787 		} else if ((err&TTY_PE && iflag&INPCK) || err&TTY_FE) {
788 			if (iflag&IGNPAR)
789 				goto endcase;
790 			else if (iflag&PARMRK) {
791 parmrk:
792 				putc(0377|TTY_QUOTE, &tp->t_rawq);
793 				putc(0|TTY_QUOTE, &tp->t_rawq);
794 				putc(c|TTY_QUOTE, &tp->t_rawq);
795 				goto endcase;
796 			} else
797 				c = 0;
798 		}
799 	}
800 	/*
801 	 * In tandem mode, check high water mark.
802 	 */
803 	if (iflag&IXOFF)
804 		ttyblock(tp);
805 	if ((tp->t_state&TS_TYPEN) == 0 && (iflag&ISTRIP))
806 		c &= 0177;
807     if ((tp->t_lflag&EXTPROC) == 0) {
808 	/*
809 	 * Check for literal nexting very first
810 	 */
811 	if (tp->t_state&TS_LNCH) {
812 		c |= TTY_QUOTE;
813 		tp->t_state &= ~TS_LNCH;
814 	}
815 	/*
816 	 * Scan for special characters.  This code
817 	 * is really just a big case statement with
818 	 * non-constant cases.  The bottom of the
819 	 * case statement is labeled ``endcase'', so goto
820 	 * it after a case match, or similar.
821 	 */
822 	/*
823 	 * Control chars which aren't controlled
824 	 * by ICANON, ISIG, or IXON.
825 	 */
826 	if (lflag&IEXTEN) {
827 		if (CCEQ(cc[VLNEXT], c)) {
828 			if (lflag&ECHO) {
829 				if (lflag&ECHOE)
830 					ttyoutstr("^\b", tp);
831 				else
832 					ttyecho(c, tp);
833 			}
834 			tp->t_state |= TS_LNCH;
835 			goto endcase;
836 		}
837 		if (CCEQ(cc[VFLUSHO], c)) {
838 			if (lflag&FLUSHO)
839 				tp->t_lflag &= ~FLUSHO;
840 			else {
841 				ttyflush(tp, FWRITE);
842 				ttyecho(c, tp);
843 				if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
844 					ttyretype(tp);
845 				tp->t_lflag |= FLUSHO;
846 			}
847 			goto startoutput;
848 		}
849 	}
850 	/*
851 	 * Signals.
852 	 */
853 	if (lflag&ISIG) {
854 		if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
855 			if ((lflag&NOFLSH) == 0)
856 				ttyflush(tp, FREAD|FWRITE);
857 			ttyecho(c, tp);
858 			pgsignal(tp->t_pgrp,
859 			    CCEQ(cc[VINTR], c) ? SIGINT : SIGQUIT, 1);
860 			goto endcase;
861 		}
862 		if (CCEQ(cc[VSUSP], c)) {
863 			if ((lflag&NOFLSH) == 0)
864 				ttyflush(tp, FREAD);
865 			ttyecho(c, tp);
866 			pgsignal(tp->t_pgrp, SIGTSTP, 1);
867 			goto endcase;
868 		}
869 	}
870 	/*
871 	 * Handle start/stop characters.
872 	 */
873 	if (iflag&IXON) {
874 		if (CCEQ(cc[VSTOP], c)) {
875 			if ((tp->t_state&TS_TTSTOP) == 0) {
876 				tp->t_state |= TS_TTSTOP;
877 				(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
878 				return;
879 			}
880 			if (!CCEQ(cc[VSTART], c))
881 				return;
882 			/*
883 			 * if VSTART == VSTOP then toggle
884 			 */
885 			goto endcase;
886 		}
887 		if (CCEQ(cc[VSTART], c))
888 			goto restartoutput;
889 	}
890 	/*
891 	 * IGNCR, ICRNL, & INLCR
892 	 */
893 	if (c == '\r') {
894 		if (iflag&IGNCR)
895 			goto endcase;
896 		else if (iflag&ICRNL)
897 			c = '\n';
898 	}
899 	else if (c == '\n' && iflag&INLCR)
900 		c = '\r';
901     }
902 	/*
903 	 * Non canonical mode; don't process line editing
904 	 * characters; check high water mark for wakeup.
905 	 *
906 	 */
907 	if ((lflag&ICANON) == 0) {
908 		if (tp->t_rawq.c_cc > TTYHOG) {
909 			if (iflag&IMAXBEL) {
910 				if (tp->t_outq.c_cc < tp->t_hiwat)
911 					(void) ttyoutput(CTRL('g'), tp);
912 			} else
913 				ttyflush(tp, FREAD | FWRITE);
914 		} else {
915 			if (putc(c, &tp->t_rawq) >= 0) {
916 				ttwakeup(tp);
917 				ttyecho(c, tp);
918 			}
919 		}
920 		goto endcase;
921 	}
922     if ((tp->t_lflag&EXTPROC) == 0) {
923 	/*
924 	 * From here on down canonical mode character
925 	 * processing takes place.
926 	 */
927 	/*
928 	 * erase (^H / ^?)
929 	 */
930 	if (CCEQ(cc[VERASE], c)) {
931 		if (tp->t_rawq.c_cc)
932 			ttyrub(unputc(&tp->t_rawq), tp);
933 		goto endcase;
934 	}
935 	/*
936 	 * kill (^U)
937 	 */
938 	if (CCEQ(cc[VKILL], c)) {
939 		if (lflag&ECHOKE && tp->t_rawq.c_cc == tp->t_rocount &&
940 		    (lflag&ECHOPRT) == 0) {
941 			while (tp->t_rawq.c_cc)
942 				ttyrub(unputc(&tp->t_rawq), tp);
943 		} else {
944 			ttyecho(c, tp);
945 			if (lflag&ECHOK || lflag&ECHOKE)
946 				ttyecho('\n', tp);
947 			while (getc(&tp->t_rawq) > 0)
948 				;
949 			tp->t_rocount = 0;
950 		}
951 		tp->t_state &= ~TS_LOCAL;
952 		goto endcase;
953 	}
954 	/*
955 	 * word erase (^W)
956 	 */
957 	if (CCEQ(cc[VWERASE], c)) {
958 		int ctype;
959 
960 #define CTYPE(c) ((lflag&ALTWERASE) ? (partab[(c)&TTY_CHARMASK]&0100) : 0)
961 		/*
962 		 * erase whitespace
963 		 */
964 		while ((c = unputc(&tp->t_rawq)) == ' ' || c == '\t')
965 			ttyrub(c, tp);
966 		if (c == -1)
967 			goto endcase;
968 		/*
969 		 * special case last char of token
970 		 */
971 		ttyrub(c, tp);
972 		c = unputc(&tp->t_rawq);
973 		if (c == -1 || c == ' ' || c == '\t') {
974 			if (c != -1)
975 				(void) putc(c, &tp->t_rawq);
976 			goto endcase;
977 		}
978 		/*
979 		 * erase rest of token
980 		 */
981 		ctype = CTYPE(c);
982 		do {
983 			ttyrub(c, tp);
984 			c = unputc(&tp->t_rawq);
985 			if (c == -1)
986 				goto endcase;
987 		} while (c != ' ' && c != '\t' && CTYPE(c) == ctype);
988 		(void) putc(c, &tp->t_rawq);
989 		goto endcase;
990 #undef CTYPE
991 	}
992 	/*
993 	 * reprint line (^R)
994 	 */
995 	if (CCEQ(cc[VREPRINT], c)) {
996 		ttyretype(tp);
997 		goto endcase;
998 	}
999 	if (CCEQ(cc[VINFO], c)) {
1000 		pgsignal(tp->t_pgrp, SIGINFO, 1);
1001 		if ((lflag&NOKERNINFO) == 0)
1002 			ttyinfo(tp);
1003 		goto endcase;
1004 	}
1005     }
1006 	/*
1007 	 * Check for input buffer overflow
1008 	 */
1009 	if (tp->t_rawq.c_cc+tp->t_canq.c_cc >= TTYHOG) {
1010 		if (iflag&IMAXBEL) {
1011 			if (tp->t_outq.c_cc < tp->t_hiwat)
1012 				(void) ttyoutput(CTRL('g'), tp);
1013 		} else
1014 			ttyflush(tp, FREAD | FWRITE);
1015 		goto endcase;
1016 	}
1017 	/*
1018 	 * Put data char in q for user and
1019 	 * wakeup on seeing a line delimiter.
1020 	 */
1021 	if (putc(c, &tp->t_rawq) >= 0) {
1022 		if (ttbreakc(c)) {
1023 			tp->t_rocount = 0;
1024 			catq(&tp->t_rawq, &tp->t_canq);
1025 			ttwakeup(tp);
1026 		} else if (tp->t_rocount++ == 0)
1027 			tp->t_rocol = tp->t_col;
1028 		if (tp->t_state&TS_ERASE) {
1029 			/*
1030 			 * end of prterase \.../
1031 			 */
1032 			tp->t_state &= ~TS_ERASE;
1033 			(void) ttyoutput('/', tp);
1034 		}
1035 		i = tp->t_col;
1036 		ttyecho(c, tp);
1037 		if (CCEQ(cc[VEOF], c) && lflag&ECHO) {
1038 			/*
1039 			 * Place the cursor over the '^' of the ^D.
1040 			 */
1041 			i = MIN(2, tp->t_col - i);
1042 			while (i > 0) {
1043 				(void) ttyoutput('\b', tp);
1044 				i--;
1045 			}
1046 		}
1047 	}
1048 endcase:
1049 	/*
1050 	 * IXANY means allow any character to restart output.
1051 	 */
1052 	if ((tp->t_state&TS_TTSTOP) && (iflag&IXANY) == 0 &&
1053 	    cc[VSTART] != cc[VSTOP])
1054 		return;
1055 restartoutput:
1056 	tp->t_state &= ~TS_TTSTOP;
1057 	tp->t_lflag &= ~FLUSHO;
1058 startoutput:
1059 	ttstart(tp);
1060 }
1061 
1062 /*
1063  * Put character on TTY output queue, adding delays,
1064  * expanding tabs, and handling the CR/NL bit.
1065  * This is called both from the top half for output,
1066  * and from interrupt level for echoing.
1067  * The arguments are the character and the tty structure.
1068  * Returns < 0 if putc succeeds, otherwise returns char to resend
1069  * Must be recursive.
1070  */
1071 ttyoutput(c, tp)
1072 	register c;
1073 	register struct tty *tp;
1074 {
1075 	register char *colp;
1076 	register ctype;
1077 	register long oflag = tp->t_oflag;
1078 
1079 	if ((oflag&OPOST) == 0) {
1080 		if (tp->t_lflag&FLUSHO)
1081 			return (-1);
1082 		if (putc(c, &tp->t_outq))
1083 			return (c);
1084 		tk_nout++;
1085 		tp->t_outcc++;
1086 		return (-1);
1087 	}
1088 	c &= TTY_CHARMASK;
1089 	/*
1090 	 * Turn tabs to spaces as required
1091 	 *
1092 	 * Special case if we have external processing, we don't
1093 	 * do the tab expansion because we'll probably get it
1094 	 * wrong.  If tab expansion needs to be done, let it
1095 	 * happen externally.
1096 	 */
1097 	if ((tp->t_lflag&EXTPROC) == 0 &&
1098 	    c == '\t' && oflag&OXTABS ) {
1099 		register int s;
1100 
1101 		c = 8 - (tp->t_col&7);
1102 		if ((tp->t_lflag&FLUSHO) == 0) {
1103 			s = spltty();		/* don't interrupt tabs */
1104 			c -= b_to_q("        ", c, &tp->t_outq);
1105 			tk_nout += c;
1106 			tp->t_outcc += c;
1107 			splx(s);
1108 		}
1109 		tp->t_col += c;
1110 		return (c ? -1 : '\t');
1111 	}
1112 	if (c == CEOT && oflag&ONOEOT)
1113 		return(-1);
1114 	tk_nout++;
1115 	tp->t_outcc++;
1116 	/*
1117 	 * turn <nl> to <cr><lf> if desired.
1118 	 */
1119 	if (c == '\n' && (tp->t_oflag&ONLCR) && ttyoutput('\r', tp) >= 0)
1120 		return (c);
1121 	if ((tp->t_lflag&FLUSHO) == 0 && putc(c, &tp->t_outq))
1122 		return (c);
1123 	/*
1124 	 * Calculate delays.
1125 	 * The numbers here represent clock ticks
1126 	 * and are not necessarily optimal for all terminals.
1127 	 *
1128 	 * SHOULD JUST ALLOW USER TO SPECIFY DELAYS
1129 	 *
1130 	 * (actually, should THROW AWAY terminals which need delays)
1131 	 */
1132 	colp = &tp->t_col;
1133 	ctype = partab[c];
1134 	c = 0;
1135 	switch (ctype&077) {
1136 
1137 	case ORDINARY:
1138 		(*colp)++;
1139 
1140 	case CONTROL:
1141 		break;
1142 
1143 	case BACKSPACE:
1144 		if (*colp)
1145 			(*colp)--;
1146 		break;
1147 
1148 	/*
1149 	 * This macro is close enough to the correct thing;
1150 	 * it should be replaced by real user settable delays
1151 	 * in any event...
1152 	 */
1153 #define	mstohz(ms)	(((ms) * hz) >> 10)
1154 	case NEWLINE:
1155 		ctype = (tp->t_flags >> 8) & 03;
1156 		if (ctype == 1) { /* tty 37 */
1157 			if (*colp > 0) {
1158 				c = (((unsigned)*colp) >> 4) + 3;
1159 				if ((unsigned)c > 6)
1160 					c = 6;
1161 			}
1162 		} else if (ctype == 2) /* vt05 */
1163 			c = mstohz(100);
1164 		*colp = 0;
1165 		break;
1166 
1167 	case TAB:
1168 		ctype = (tp->t_flags >> 10) & 03;
1169 		if (ctype == 1) { /* tty 37 */
1170 			c = 1 - (*colp | ~07);
1171 			if (c < 5)
1172 				c = 0;
1173 		}
1174 		*colp |= 07;
1175 		(*colp)++;
1176 		break;
1177 
1178 	case VTAB:
1179 		if (tp->t_flags&VTDELAY) /* tty 37 */
1180 			c = 0177;
1181 		break;
1182 
1183 	case RETURN:
1184 		ctype = (tp->t_flags >> 12) & 03;
1185 		if (ctype == 1) /* tn 300 */
1186 			c = mstohz(83);
1187 		else if (ctype == 2) /* ti 700 */
1188 			c = mstohz(166);
1189 		else if (ctype == 3) { /* concept 100 */
1190 			int i;
1191 
1192 			if ((i = *colp) >= 0)
1193 				for (; i < 9; i++)
1194 					(void) putc(0177, &tp->t_outq);
1195 		}
1196 		*colp = 0;
1197 	}
1198 	if (c && (tp->t_lflag&FLUSHO) == 0)
1199 		(void) putc(c|TTY_QUOTE, &tp->t_outq);
1200 	return (-1);
1201 }
1202 #undef mstohz
1203 
1204 /*
1205  * Called from device's read routine after it has
1206  * calculated the tty-structure given as argument.
1207  */
1208 ttread(tp, uio, flag)
1209 	register struct tty *tp;
1210 	struct uio *uio;
1211 {
1212 	register struct clist *qp;
1213 	register int c;
1214 	register long lflag;
1215 	register u_char *cc = tp->t_cc;
1216 	int s, first, error = 0;
1217 
1218 loop:
1219 	lflag = tp->t_lflag;
1220 	s = spltty();
1221 	/*
1222 	 * take pending input first
1223 	 */
1224 	if (lflag&PENDIN)
1225 		ttypend(tp);
1226 	splx(s);
1227 
1228 	/*
1229 	 * Hang process if it's in the background.
1230 	 */
1231 	if (isbackground(u.u_procp, tp)) {
1232 		if ((u.u_procp->p_sigignore & sigmask(SIGTTIN)) ||
1233 		   (u.u_procp->p_sigmask & sigmask(SIGTTIN)) ||
1234 		    u.u_procp->p_flag&SVFORK || u.u_procp->p_pgrp->pg_jobc == 0)
1235 			return (EIO);
1236 		pgsignal(u.u_procp->p_pgrp, SIGTTIN, 1);
1237 		if ((error = tsleep((caddr_t)&lbolt, TTIPRI | PCATCH,
1238 				    ttybg, 0)) ||
1239 		    (error = ttclosed(tp)))
1240 			return (error);
1241 		goto loop;
1242 	}
1243 
1244 	/*
1245 	 * If canonical, use the canonical queue,
1246 	 * else use the raw queue.
1247 	 *
1248 	 * XXX - should get rid of canonical queue.
1249 	 * (actually, should get rid of clists...)
1250 	 */
1251 	qp = lflag&ICANON ? &tp->t_canq : &tp->t_rawq;
1252 
1253 	/*
1254 	 * If there is no input, sleep on rawq
1255 	 * awaiting hardware receipt and notification.
1256 	 * If we have data, we don't need to check for carrier.
1257 	 */
1258 	s = spltty();
1259 	if (qp->c_cc <= 0) {
1260 		int carrier;
1261 
1262 		carrier = (tp->t_state&TS_CARR_ON) || (tp->t_cflag&CLOCAL);
1263 		if (!carrier && tp->t_state&TS_ISOPEN) {
1264 			splx(s);
1265 			return (0);	/* EOF */
1266 		}
1267 		if (flag & IO_NDELAY) {
1268 			splx(s);
1269 			return (EWOULDBLOCK);
1270 		}
1271 		error = tsleep((caddr_t)&tp->t_rawq, TTIPRI | PCATCH,
1272 		    carrier ? ttyin : ttopen, 0);
1273 		splx(s);
1274 		if (error || (error = ttclosed(tp)))
1275 			return (error);
1276 		goto loop;
1277 	}
1278 	splx(s);
1279 
1280 	/*
1281 	 * Input present, check for input mapping and processing.
1282 	 */
1283 	first = 1;
1284 	while ((c = getc(qp)) >= 0) {
1285 		/*
1286 		 * delayed suspend (^Y)
1287 		 */
1288 		if (CCEQ(cc[VDSUSP], c) && lflag&ISIG) {
1289 			pgsignal(tp->t_pgrp, SIGTSTP, 1);
1290 			if (first) {
1291 				if ((error = tsleep((caddr_t)&lbolt,
1292 					    TTIPRI | PCATCH, ttybg, 0)) ||
1293 				    (error = ttclosed(tp)))
1294 					break;
1295 				goto loop;
1296 			}
1297 			break;
1298 		}
1299 		/*
1300 		 * Interpret EOF only in canonical mode.
1301 		 */
1302 		if (CCEQ(cc[VEOF], c) && lflag&ICANON)
1303 			break;
1304 		/*
1305 		 * Give user character.
1306 		 */
1307  		error = ureadc(c, uio);
1308 		if (error)
1309 			break;
1310  		if (uio->uio_resid == 0)
1311 			break;
1312 		/*
1313 		 * In canonical mode check for a "break character"
1314 		 * marking the end of a "line of input".
1315 		 */
1316 		if (lflag&ICANON && ttbreakc(c))
1317 			break;
1318 		first = 0;
1319 	}
1320 	/*
1321 	 * Look to unblock output now that (presumably)
1322 	 * the input queue has gone down.
1323 	 */
1324 	if (tp->t_state&TS_TBLOCK && tp->t_rawq.c_cc < TTYHOG/5) {
1325 		if (cc[VSTART] != _POSIX_VDISABLE
1326 		   && putc(cc[VSTART], &tp->t_outq) == 0) {
1327 			tp->t_state &= ~TS_TBLOCK;
1328 			ttstart(tp);
1329 		}
1330 	}
1331 	return (error);
1332 }
1333 
1334 /*
1335  * Check the output queue on tp for space for a kernel message
1336  * (from uprintf/tprintf).  Allow some space over the normal
1337  * hiwater mark so we don't lose messages due to normal flow
1338  * control, but don't let the tty run amok.
1339  * Sleeps here are not interruptible, but we return prematurely
1340  * if new signals come in.
1341  */
1342 ttycheckoutq(tp, wait)
1343 	register struct tty *tp;
1344 	int wait;
1345 {
1346 	int hiwat, s, oldsig;
1347 
1348 	hiwat = tp->t_hiwat;
1349 	s = spltty();
1350 	oldsig = u.u_procp->p_sig;
1351 	if (tp->t_outq.c_cc > hiwat + 200)
1352 		while (tp->t_outq.c_cc > hiwat) {
1353 			ttstart(tp);
1354 			if (wait == 0 || u.u_procp->p_sig != oldsig) {
1355 				splx(s);
1356 				return (0);
1357 			}
1358 			timeout(wakeup, (caddr_t)&tp->t_outq, hz);
1359 			tp->t_state |= TS_ASLEEP;
1360 			sleep((caddr_t)&tp->t_outq, PZERO - 1);
1361 		}
1362 	splx(s);
1363 	return (1);
1364 }
1365 
1366 /*
1367  * Called from the device's write routine after it has
1368  * calculated the tty-structure given as argument.
1369  */
1370 ttwrite(tp, uio, flag)
1371 	register struct tty *tp;
1372 	register struct uio *uio;
1373 {
1374 	register char *cp;
1375 	register int cc = 0, ce;
1376 	int i, hiwat, cnt, error, s;
1377 	char obuf[OBUFSIZ];
1378 
1379 	hiwat = tp->t_hiwat;
1380 	cnt = uio->uio_resid;
1381 	error = 0;
1382 loop:
1383 	s = spltty();
1384 	if ((tp->t_state&TS_CARR_ON) == 0 && (tp->t_cflag&CLOCAL) == 0) {
1385 		if (tp->t_state&TS_ISOPEN) {
1386 			splx(s);
1387 			return (EIO);
1388 		} else if (flag & IO_NDELAY) {
1389 			splx(s);
1390 			error = EWOULDBLOCK;
1391 			goto out;
1392 		} else {
1393 			/*
1394 			 * sleep awaiting carrier
1395 			 */
1396 			error = tsleep((caddr_t)&tp->t_rawq, TTIPRI | PCATCH,
1397 			    ttopen, 0);
1398 			splx(s);
1399 			if (error || (error = ttclosed(tp)))
1400 				goto out;
1401 			goto loop;
1402 		}
1403 	}
1404 	splx(s);
1405 	/*
1406 	 * Hang the process if it's in the background.
1407 	 */
1408 	if (isbackground(u.u_procp, tp) &&
1409 	    (tp->t_lflag&TOSTOP) && (u.u_procp->p_flag&SVFORK)==0 &&
1410 	    (u.u_procp->p_sigignore & sigmask(SIGTTOU)) == 0 &&
1411 	    (u.u_procp->p_sigmask & sigmask(SIGTTOU)) == 0 &&
1412 	     u.u_procp->p_pgrp->pg_jobc) {
1413 		pgsignal(u.u_procp->p_pgrp, SIGTTOU, 1);
1414 		if ((error = tsleep((caddr_t)&lbolt, TTIPRI | PCATCH,
1415 				     ttybg, 0)) ||
1416 		    (error = ttclosed(tp)))
1417 			goto out;
1418 		goto loop;
1419 	}
1420 	/*
1421 	 * Process the user's data in at most OBUFSIZ
1422 	 * chunks.  Perform any output translation.
1423 	 * Keep track of high water mark, sleep on overflow
1424 	 * awaiting device aid in acquiring new space.
1425 	 */
1426 	while (uio->uio_resid > 0 || cc > 0) {
1427 		if (tp->t_lflag&FLUSHO) {
1428 			uio->uio_resid = 0;
1429 			return (0);
1430 		}
1431 		if (tp->t_outq.c_cc > hiwat)
1432 			goto ovhiwat;
1433 		/*
1434 		 * Grab a hunk of data from the user,
1435 		 * unless we have some leftover from last time.
1436 		 */
1437 		if (cc == 0) {
1438 			cc = min(uio->uio_resid, OBUFSIZ);
1439 			cp = obuf;
1440 			error = uiomove(cp, cc, uio);
1441 			if (error) {
1442 				cc = 0;
1443 				break;
1444 			}
1445 		}
1446 		/*
1447 		 * If nothing fancy need be done, grab those characters we
1448 		 * can handle without any of ttyoutput's processing and
1449 		 * just transfer them to the output q.  For those chars
1450 		 * which require special processing (as indicated by the
1451 		 * bits in partab), call ttyoutput.  After processing
1452 		 * a hunk of data, look for FLUSHO so ^O's will take effect
1453 		 * immediately.
1454 		 */
1455 		while (cc > 0) {
1456 			if ((tp->t_oflag&OPOST) == 0)
1457 				ce = cc;
1458 			else {
1459 				ce = cc - scanc((unsigned)cc, (u_char *)cp,
1460 				   (u_char *)partab, 077);
1461 				/*
1462 				 * If ce is zero, then we're processing
1463 				 * a special character through ttyoutput.
1464 				 */
1465 				if (ce == 0) {
1466 					tp->t_rocount = 0;
1467 					if (ttyoutput(*cp, tp) >= 0) {
1468 					    /* no c-lists, wait a bit */
1469 					    ttstart(tp);
1470 					    if ((error = tsleep((caddr_t)&lbolt,
1471 						TTOPRI | PCATCH, ttybuf, 0)) ||
1472 						(error = ttclosed(tp)))
1473 						    break;
1474 					    goto loop;
1475 					}
1476 					cp++, cc--;
1477 					if ((tp->t_lflag&FLUSHO) ||
1478 					    tp->t_outq.c_cc > hiwat)
1479 						goto ovhiwat;
1480 					continue;
1481 				}
1482 			}
1483 			/*
1484 			 * A bunch of normal characters have been found,
1485 			 * transfer them en masse to the output queue and
1486 			 * continue processing at the top of the loop.
1487 			 * If there are any further characters in this
1488 			 * <= OBUFSIZ chunk, the first should be a character
1489 			 * requiring special handling by ttyoutput.
1490 			 */
1491 			tp->t_rocount = 0;
1492 			i = b_to_q(cp, ce, &tp->t_outq);
1493 			ce -= i;
1494 			tp->t_col += ce;
1495 			cp += ce, cc -= ce, tk_nout += ce;
1496 			tp->t_outcc += ce;
1497 			if (i > 0) {
1498 				/* out of c-lists, wait a bit */
1499 				ttstart(tp);
1500 				if ((error = tsleep((caddr_t)&lbolt,
1501 					    TTOPRI | PCATCH, ttybuf, 0)) ||
1502 				    (error = ttclosed(tp)))
1503 					break;
1504 				goto loop;
1505 			}
1506 			if (tp->t_lflag&FLUSHO || tp->t_outq.c_cc > hiwat)
1507 				break;
1508 		}
1509 		ttstart(tp);
1510 	}
1511 out:
1512 	/*
1513 	 * If cc is nonzero, we leave the uio structure inconsistent,
1514 	 * as the offset and iov pointers have moved forward,
1515 	 * but it doesn't matter (the call will either return short
1516 	 * or restart with a new uio).
1517 	 */
1518 	uio->uio_resid += cc;
1519 	return (error);
1520 
1521 ovhiwat:
1522 	ttstart(tp);
1523 	s = spltty();
1524 	/*
1525 	 * This can only occur if FLUSHO is set in t_lflag,
1526 	 * or if ttstart/oproc is synchronous (or very fast).
1527 	 */
1528 	if (tp->t_outq.c_cc <= hiwat) {
1529 		splx(s);
1530 		goto loop;
1531 	}
1532 	if (flag & IO_NDELAY) {
1533 		splx(s);
1534 		uio->uio_resid += cc;
1535 		if (uio->uio_resid == cnt)
1536 			return (EWOULDBLOCK);
1537 		return (0);
1538 	}
1539 	tp->t_state |= TS_ASLEEP;
1540 	error = tsleep((caddr_t)&tp->t_outq, TTOPRI | PCATCH, ttyout, 0);
1541 	splx(s);
1542 	if (error || (error = ttclosed(tp)))
1543 		goto out;
1544 	goto loop;
1545 }
1546 
1547 /*
1548  * Rubout one character from the rawq of tp
1549  * as cleanly as possible.
1550  */
1551 ttyrub(c, tp)
1552 	register c;
1553 	register struct tty *tp;
1554 {
1555 	register char *cp;
1556 	register int savecol;
1557 	int s;
1558 	char *nextc();
1559 
1560 	if ((tp->t_lflag&ECHO) == 0 || (tp->t_lflag&EXTPROC))
1561 		return;
1562 	tp->t_lflag &= ~FLUSHO;
1563 	if (tp->t_lflag&ECHOE) {
1564 		if (tp->t_rocount == 0) {
1565 			/*
1566 			 * Screwed by ttwrite; retype
1567 			 */
1568 			ttyretype(tp);
1569 			return;
1570 		}
1571 		if (c == ('\t'|TTY_QUOTE) || c == ('\n'|TTY_QUOTE))
1572 			ttyrubo(tp, 2);
1573 		else switch (partab[c&=0377]&077) {
1574 
1575 		case ORDINARY:
1576 			ttyrubo(tp, 1);
1577 			break;
1578 
1579 		case VTAB:
1580 		case BACKSPACE:
1581 		case CONTROL:
1582 		case RETURN:
1583 			if (tp->t_lflag&ECHOCTL)
1584 				ttyrubo(tp, 2);
1585 			break;
1586 
1587 		case TAB: {
1588 			int c;
1589 
1590 			if (tp->t_rocount < tp->t_rawq.c_cc) {
1591 				ttyretype(tp);
1592 				return;
1593 			}
1594 			s = spltty();
1595 			savecol = tp->t_col;
1596 			tp->t_state |= TS_CNTTB;
1597 			tp->t_lflag |= FLUSHO;
1598 			tp->t_col = tp->t_rocol;
1599 			cp = tp->t_rawq.c_cf;
1600 			if (cp)
1601 				c = *cp;	/* XXX FIX NEXTC */
1602 			for (; cp; cp = nextc(&tp->t_rawq, cp, &c))
1603 				ttyecho(c, tp);
1604 			tp->t_lflag &= ~FLUSHO;
1605 			tp->t_state &= ~TS_CNTTB;
1606 			splx(s);
1607 			/*
1608 			 * savecol will now be length of the tab
1609 			 */
1610 			savecol -= tp->t_col;
1611 			tp->t_col += savecol;
1612 			if (savecol > 8)
1613 				savecol = 8;		/* overflow screw */
1614 			while (--savecol >= 0)
1615 				(void) ttyoutput('\b', tp);
1616 			break;
1617 		}
1618 
1619 		default:
1620 			/* XXX */
1621 			printf("ttyrub: would panic c = %d, val = %d\n",
1622 				c, partab[c&=0377]&077);
1623 			/*panic("ttyrub");*/
1624 		}
1625 	} else if (tp->t_lflag&ECHOPRT) {
1626 		if ((tp->t_state&TS_ERASE) == 0) {
1627 			(void) ttyoutput('\\', tp);
1628 			tp->t_state |= TS_ERASE;
1629 		}
1630 		ttyecho(c, tp);
1631 	} else
1632 		ttyecho(tp->t_cc[VERASE], tp);
1633 	tp->t_rocount--;
1634 }
1635 
1636 /*
1637  * Crt back over cnt chars perhaps
1638  * erasing them.
1639  */
1640 ttyrubo(tp, cnt)
1641 	register struct tty *tp;
1642 	int cnt;
1643 {
1644 
1645 	while (--cnt >= 0)
1646 		ttyoutstr("\b \b", tp);
1647 }
1648 
1649 /*
1650  * Reprint the rawq line.
1651  * We assume c_cc has already been checked.
1652  */
1653 ttyretype(tp)
1654 	register struct tty *tp;
1655 {
1656 	register char *cp;
1657 	char *nextc();
1658 	int s, c;
1659 
1660 	if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
1661 		ttyecho(tp->t_cc[VREPRINT], tp);
1662 	(void) ttyoutput('\n', tp);
1663 	s = spltty();
1664 	/*** XXX *** FIX *** NEXTC IS BROKEN - DOESN'T CHECK QUOTE
1665 	  BIT OF FIRST CHAR ****/
1666 	for (cp = tp->t_canq.c_cf, c=(cp?*cp:0); cp; cp = nextc(&tp->t_canq, cp, &c)) {
1667 		ttyecho(c, tp);
1668 	}
1669 	for (cp = tp->t_rawq.c_cf, c=(cp?*cp:0); cp; cp = nextc(&tp->t_rawq, cp, &c)) {
1670 		ttyecho(c, tp);
1671 	}
1672 	tp->t_state &= ~TS_ERASE;
1673 	splx(s);
1674 	tp->t_rocount = tp->t_rawq.c_cc;
1675 	tp->t_rocol = 0;
1676 }
1677 
1678 /*
1679  * Echo a typed character to the terminal.
1680  */
1681 ttyecho(c, tp)
1682 	register c;
1683 	register struct tty *tp;
1684 {
1685 	if ((tp->t_state&TS_CNTTB) == 0)
1686 		tp->t_lflag &= ~FLUSHO;
1687 	if (((tp->t_lflag&ECHO) == 0 && ((tp->t_lflag&ECHONL) == 0 ||
1688 					  c == '\n')) || (tp->t_lflag&EXTPROC))
1689 		return;
1690 	if (tp->t_lflag&ECHOCTL) {
1691 		if ((c&TTY_CHARMASK) <= 037 && c != '\t' && c != '\n' ||
1692 		    c == 0177) {
1693 			(void) ttyoutput('^', tp);
1694 			c &= TTY_CHARMASK;
1695 			if (c == 0177)
1696 				c = '?';
1697 			else
1698 				c += 'A' - 1;
1699 		}
1700 	}
1701 	(void) ttyoutput(c, tp);
1702 }
1703 
1704 /*
1705  * send string cp to tp
1706  */
1707 ttyoutstr(cp, tp)
1708 	register char *cp;
1709 	register struct tty *tp;
1710 {
1711 	register char c;
1712 
1713 	while (c = *cp++)
1714 		(void) ttyoutput(c, tp);
1715 }
1716 
1717 ttwakeup(tp)
1718 	struct tty *tp;
1719 {
1720 
1721 	if (tp->t_rsel) {
1722 		selwakeup(tp->t_rsel, tp->t_state&TS_RCOLL);
1723 		tp->t_state &= ~TS_RCOLL;
1724 		tp->t_rsel = 0;
1725 	}
1726 	if (tp->t_state & TS_ASYNC)
1727 		pgsignal(tp->t_pgrp, SIGIO, 1);
1728 	wakeup((caddr_t)&tp->t_rawq);
1729 }
1730 
1731 /*
1732  * set tty hi and low water marks
1733  *
1734  * Try to arrange the dynamics so there's about one second
1735  * from hi to low water.
1736  *
1737  */
1738 ttsetwater(tp)
1739 	struct tty *tp;
1740 {
1741 	register cps = tp->t_ospeed / 10;
1742 	register x;
1743 
1744 #define clamp(x, h, l) ((x)>h ? h : ((x)<l) ? l : (x))
1745 	tp->t_lowat = x = clamp(cps/2, TTMAXLOWAT, TTMINLOWAT);
1746 	x += cps;
1747 	x = clamp(x, TTMAXHIWAT, TTMINHIWAT);
1748 	tp->t_hiwat = roundup(x, CBSIZE);
1749 #undef clamp
1750 }
1751 
1752 ttspeedtab(speed, table)
1753 	struct speedtab table[];
1754 {
1755 	register int i;
1756 
1757 	for (i = 0; table[i].sp_speed != -1; i++)
1758 		if (table[i].sp_speed == speed)
1759 			return(table[i].sp_code);
1760 	return(-1);
1761 }
1762 
1763 int ttyhostname = 0;
1764 /*
1765  * (^T)
1766  * Report on state of foreground process group.
1767  */
1768 ttyinfo(tp)
1769 	struct tty *tp;
1770 {
1771 	register struct proc *p, *pick = NULL;
1772 	register char *cp = hostname;
1773 	int x, s;
1774 	struct timeval utime, stime;
1775 #define	pgtok(a)	(((a)*NBPG)/1024)
1776 
1777 	if (ttycheckoutq(tp,0) == 0)
1778 		return;
1779 	/*
1780 	 * hostname
1781 	 */
1782 	if (ttyhostname) {
1783 		if (*cp == '\0')
1784 			ttyprintf(tp, "amnesia");
1785 		else
1786 			while (*cp && *cp != '.')
1787 				tputchar(*cp++, tp);
1788 		tputchar(' ');
1789 	}
1790 	/*
1791 	 * load average
1792 	 */
1793 	x = (averunnable[0] * 100 + FSCALE/2) >> FSHIFT;
1794 	ttyprintf(tp, "load: %d.", x/100);
1795 	ttyoutint(x%100, 10, 2, tp);
1796 	if (tp->t_session == NULL)
1797 		ttyprintf(tp, " not a controlling terminal\n");
1798 	else if (tp->t_pgrp == NULL)
1799 		ttyprintf(tp, " no foreground process group\n");
1800 	else if ((p = tp->t_pgrp->pg_mem) == NULL)
1801 		ttyprintf(tp, " empty foreground process group\n");
1802 	else {
1803 		/* pick interesting process */
1804 		for (; p != NULL; p = p->p_pgrpnxt) {
1805 			if (proc_compare(pick, p))
1806 				pick = p;
1807 		}
1808 		ttyprintf(tp, "  cmd: %s %d [%s] ",
1809 			pick->p_comm, pick->p_pid,
1810 			pick->p_wmesg ? pick->p_wmesg : "running");
1811 		/*
1812 		 * cpu time
1813 		 */
1814 		if (u.u_procp == pick)
1815 			s = splclock();
1816 		utime = pick->p_utime;
1817 		stime = pick->p_stime;
1818 		if (u.u_procp == pick)
1819 			splx(s);
1820 		/* user time */
1821 		x = (utime.tv_usec + 5000) / 10000; /* scale to 100's */
1822 		ttyoutint(utime.tv_sec, 10, 1, tp);
1823 		tputchar('.', tp);
1824 		ttyoutint(x, 10, 2, tp);
1825 		tputchar('u', tp);
1826 		tputchar(' ', tp);
1827 		/* system time */
1828 		x = (stime.tv_usec + 5000) / 10000; /* scale to 100's */
1829 		ttyoutint(stime.tv_sec, 10, 1, tp);
1830 		tputchar('.', tp);
1831 		ttyoutint(x, 10, 2, tp);
1832 		tputchar('s', tp);
1833 		tputchar(' ', tp);
1834 		/*
1835 		 * pctcpu
1836 		 */
1837 		x = pick->p_pctcpu * 10000 + FSCALE/2 >> FSHIFT;
1838 		ttyoutint(x/100, 10, 1, tp);
1839 #ifdef notdef	/* do we really want this ??? */
1840 		tputchar('.', tp);
1841 		ttyoutint(x%100, 10, 2, tp);
1842 #endif
1843 		ttyprintf(tp, "%% %dk\n", pgtok(pick->p_ssize + pick->p_dsize));
1844 	}
1845 	tp->t_rocount = 0;	/* so pending input will be retyped if BS */
1846 }
1847 
1848 ttyoutint(n, base, min, tp)
1849 	register int n, base, min;
1850 	register struct tty *tp;
1851 {
1852 	char info[16];
1853 	register char *p = info;
1854 
1855 	while (--min >= 0 || n) {
1856 		*p++ = "0123456789abcdef"[n%base];
1857 		n /= base;
1858 	}
1859 	while (p > info)
1860 		ttyoutput(*--p, tp);
1861 }
1862 
1863 /*
1864  * Returns 1 if p2 is "better" than p1
1865  *
1866  * The algorithm for picking the "interesting" process is thus:
1867  *
1868  *	1) (Only foreground processes are eligable - implied)
1869  *	2) Runnable processes are favored over anything
1870  *	   else.  The runner with the highest cpu
1871  *	   utilization is picked (p_cpu).  Ties are
1872  *	   broken by picking the highest pid.
1873  *	3  Next, the sleeper with the shortest sleep
1874  *	   time is favored.  With ties, we pick out
1875  *	   just "short-term" sleepers (SSINTR == 0).
1876  *	   Further ties are broken by picking the highest
1877  *	   pid.
1878  *
1879  */
1880 #define isrun(p)	(((p)->p_stat == SRUN) || ((p)->p_stat == SIDL))
1881 proc_compare(p1, p2)
1882 	register struct proc *p1, *p2;
1883 {
1884 
1885 	if (p1 == NULL)
1886 		return (1);
1887 	/*
1888 	 * see if at least one of them is runnable
1889 	 */
1890 	switch (isrun(p1)<<1 | isrun(p2)) {
1891 	case 0x01:
1892 		return (1);
1893 	case 0x10:
1894 		return (0);
1895 	case 0x11:
1896 		/*
1897 		 * tie - favor one with highest recent cpu utilization
1898 		 */
1899 		if (p2->p_cpu > p1->p_cpu)
1900 			return (1);
1901 		if (p1->p_cpu > p2->p_cpu)
1902 			return (0);
1903 		return (p2->p_pid > p1->p_pid);	/* tie - return highest pid */
1904 	}
1905 	/*
1906 	 * pick the one with the smallest sleep time
1907 	 */
1908 	if (p2->p_slptime > p1->p_slptime)
1909 		return (0);
1910 	if (p1->p_slptime > p2->p_slptime)
1911 		return (1);
1912 	/*
1913 	 * favor one sleeping in a non-interruptible sleep
1914 	 */
1915 	if (p1->p_flag&SSINTR && (p2->p_flag&SSINTR) == 0)
1916 		return (1);
1917 	if (p2->p_flag&SSINTR && (p1->p_flag&SSINTR) == 0)
1918 		return (0);
1919 	return(p2->p_pid > p1->p_pid);		/* tie - return highest pid */
1920 }
1921 #define TOTTY	0x2	/* XXX should be in header */
1922 /*VARARGS2*/
1923 ttyprintf(tp, fmt, x1)
1924 	struct tty *tp;
1925 	char *fmt;
1926 	unsigned x1;
1927 {
1928 	prf(fmt, &x1, TOTTY, (caddr_t)tp);
1929 }
1930 
1931 /*
1932  * Output char to tty; console putchar style.
1933  */
1934 tputchar(c, tp)
1935 	int c;
1936 	struct tty *tp;
1937 {
1938 	register s = spltty();
1939 
1940 	if ((tp->t_state & (TS_CARR_ON | TS_ISOPEN))
1941 	    == (TS_CARR_ON | TS_ISOPEN)) {
1942 		if (c == '\n')
1943 			(void) ttyoutput('\r', tp);
1944 		(void) ttyoutput(c, tp);
1945 		ttstart(tp);
1946 		splx(s);
1947 		return (0);
1948 	}
1949 	splx(s);
1950 	return (-1);
1951 }
1952