xref: /csrg-svn/sys/kern/tty.c (revision 49594)
1 /*-
2  * Copyright (c) 1982, 1986, 1990 The Regents of the University of California.
3  * Copyright (c) 1991 The Regents of the University of California.
4  * All rights reserved.
5  *
6  * %sccs.include.redist.c%
7  *
8  *	@(#)tty.c	7.42 (Berkeley) 05/09/91
9  */
10 
11 #include "param.h"
12 #include "systm.h"
13 #include "ioctl.h"
14 #define TTYDEFCHARS
15 #include "tty.h"
16 #undef TTYDEFCHARS
17 #include "proc.h"
18 #include "file.h"
19 #include "conf.h"
20 #include "dkstat.h"
21 #include "uio.h"
22 #include "kernel.h"
23 #include "vnode.h"
24 #include "syslog.h"
25 
26 #include "vm/vm.h"
27 
28 /* symbolic sleep message strings */
29 char ttyin[] = "ttyin";
30 char ttyout[] = "ttyout";
31 char ttopen[] = "ttyopn";
32 char ttclos[] = "ttycls";
33 char ttybg[] = "ttybg";
34 char ttybuf[] = "ttybuf";
35 
36 /*
37  * Table giving parity for characters and indicating
38  * character classes to tty driver. The 8th bit
39  * indicates parity, the 7th bit indicates the character
40  * is an alphameric or underscore (for ALTWERASE), and the
41  * low 6 bits indicate delay type.  If the low 6 bits are 0
42  * then the character needs no special processing on output;
43  * classes other than 0 might be translated or (not currently)
44  * require delays.
45  */
46 #define	PARITY(c)	(partab[c] & 0x80)
47 #define	ISALPHA(c)	(partab[(c)&TTY_CHARMASK] & 0x40)
48 #define	CCLASSMASK	0x3f
49 #define	CCLASS(c)	(partab[c] & CCLASSMASK)
50 
51 #define	E	0x00	/* even parity */
52 #define	O	0x80	/* odd parity */
53 #define	ALPHA	0x40	/* alpha or underscore */
54 
55 #define	NO	ORDINARY
56 #define	NA	ORDINARY|ALPHA
57 #define	CC	CONTROL
58 #define	BS	BACKSPACE
59 #define	NL	NEWLINE
60 #define	TB	TAB
61 #define	VT	VTAB
62 #define	CR	RETURN
63 
64 char partab[] = {
65 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* nul - bel */
66 	O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC, /* bs - si */
67 	O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC, /* dle - etb */
68 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* can - us */
69 	O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* sp - ' */
70 	E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO, /* ( - / */
71 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* 0 - 7 */
72 	O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* 8 - ? */
73 	O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* @ - G */
74 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* H - O */
75 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* P - W */
76 	O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA, /* X - _ */
77 	E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* ` - g */
78 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* h - o */
79 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* p - w */
80 	E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC, /* x - del */
81 	/*
82 	 * "meta" chars; should be settable per charset.
83 	 * For now, treat all as normal characters.
84 	 */
85 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
86 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
87 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
88 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
89 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
90 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
91 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
92 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
93 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
94 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
95 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
96 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
97 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
98 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
99 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
100 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
101 };
102 #undef	NO
103 #undef	NA
104 #undef	CC
105 #undef	BS
106 #undef	NL
107 #undef	TB
108 #undef	VT
109 #undef	CR
110 
111 extern struct tty *constty;		/* temporary virtual console */
112 
113 /*
114  * Is 'c' a line delimiter ("break" character)?
115  */
116 #define ttbreakc(c) ((c) == '\n' || ((c) == cc[VEOF] || \
117 	(c) == cc[VEOL] || (c) == cc[VEOL2]) && (c) != _POSIX_VDISABLE)
118 
119 ttychars(tp)
120 	struct tty *tp;
121 {
122 
123 	bcopy(ttydefchars, tp->t_cc, sizeof(ttydefchars));
124 }
125 
126 /*
127  * Flush tty after output has drained.
128  */
129 ttywflush(tp)
130 	struct tty *tp;
131 {
132 	int error;
133 
134 	if ((error = ttywait(tp)) == 0)
135 		ttyflush(tp, FREAD);
136 	return (error);
137 }
138 
139 /*
140  * Wait for output to drain.
141  */
142 ttywait(tp)
143 	register struct tty *tp;
144 {
145 	int error = 0, s = spltty();
146 
147 	while ((tp->t_outq.c_cc || tp->t_state&TS_BUSY) &&
148 	    (tp->t_state&TS_CARR_ON || tp->t_cflag&CLOCAL) &&
149 	    tp->t_oproc) {
150 		(*tp->t_oproc)(tp);
151 		tp->t_state |= TS_ASLEEP;
152 		if (error = ttysleep(tp, (caddr_t)&tp->t_outq,
153 		    TTOPRI | PCATCH, ttyout, 0))
154 			break;
155 	}
156 	splx(s);
157 	return (error);
158 }
159 
160 #define	flushq(qq) { \
161 	register struct clist *q = qq; \
162 	if (q->c_cc) \
163 		ndflush(q, q->c_cc); \
164 }
165 
166 /*
167  * Flush TTY read and/or write queues,
168  * notifying anyone waiting.
169  */
170 ttyflush(tp, rw)
171 	register struct tty *tp;
172 {
173 	register s;
174 
175 	s = spltty();
176 	if (rw & FREAD) {
177 		flushq(&tp->t_canq);
178 		flushq(&tp->t_rawq);
179 		tp->t_rocount = 0;
180 		tp->t_rocol = 0;
181 		tp->t_state &= ~TS_LOCAL;
182 		ttwakeup(tp);
183 	}
184 	if (rw & FWRITE) {
185 		tp->t_state &= ~TS_TTSTOP;
186 		(*cdevsw[major(tp->t_dev)].d_stop)(tp, rw);
187 		flushq(&tp->t_outq);
188 		wakeup((caddr_t)&tp->t_outq);
189 		if (tp->t_wsel) {
190 			selwakeup(tp->t_wsel, tp->t_state & TS_WCOLL);
191 			tp->t_wsel = 0;
192 			tp->t_state &= ~TS_WCOLL;
193 		}
194 	}
195 	splx(s);
196 }
197 
198 /*
199  * Send stop character on input overflow.
200  */
201 ttyblock(tp)
202 	register struct tty *tp;
203 {
204 	register x;
205 
206 	x = tp->t_rawq.c_cc + tp->t_canq.c_cc;
207 	if (tp->t_rawq.c_cc > TTYHOG) {
208 		ttyflush(tp, FREAD|FWRITE);
209 		tp->t_state &= ~TS_TBLOCK;
210 	}
211 	/*
212 	 * Block further input iff:
213 	 * Current input > threshold AND input is available to user program
214 	 */
215 	if (x >= TTYHOG/2 && (tp->t_state & TS_TBLOCK) == 0 &&
216 	    ((tp->t_lflag&ICANON) == 0) || (tp->t_canq.c_cc > 0) &&
217 	    tp->t_cc[VSTOP] != _POSIX_VDISABLE) {
218 		if (putc(tp->t_cc[VSTOP], &tp->t_outq) == 0) {
219 			tp->t_state |= TS_TBLOCK;
220 			ttstart(tp);
221 		}
222 	}
223 }
224 
225 ttstart(tp)
226 	struct tty *tp;
227 {
228 
229 	if (tp->t_oproc)		/* kludge for pty */
230 		(*tp->t_oproc)(tp);
231 }
232 
233 ttrstrt(tp)				/* XXX */
234 	struct tty *tp;
235 {
236 
237 #ifdef DIAGNOSTIC
238 	if (tp == 0)
239 		panic("ttrstrt");
240 #endif
241 	tp->t_state &= ~TS_TIMEOUT;
242 	ttstart(tp);
243 }
244 
245 
246 /*
247  * Common code for ioctls on tty devices.
248  * Called after line-discipline-specific ioctl
249  * has been called to do discipline-specific functions
250  * and/or reject any of these ioctl commands.
251  */
252 /*ARGSUSED*/
253 ttioctl(tp, com, data, flag)
254 	register struct tty *tp;
255 	caddr_t data;
256 {
257 	register struct proc *p = curproc;		/* XXX */
258 	extern int nldisp;
259 	int s, error;
260 
261 	/*
262 	 * If the ioctl involves modification,
263 	 * hang if in the background.
264 	 */
265 	switch (com) {
266 
267 	case TIOCSETD:
268 	case TIOCFLUSH:
269 	/*case TIOCSPGRP:*/
270 	case TIOCSTI:
271 	case TIOCSWINSZ:
272 	case TIOCSETA:
273 	case TIOCSETAW:
274 	case TIOCSETAF:
275 #ifdef COMPAT_43
276 	case TIOCSETP:
277 	case TIOCSETN:
278 	case TIOCSETC:
279 	case TIOCSLTC:
280 	case TIOCLBIS:
281 	case TIOCLBIC:
282 	case TIOCLSET:
283 	case OTIOCSETD:
284 #endif
285 		while (isbackground(curproc, tp) &&
286 		   p->p_pgrp->pg_jobc && (p->p_flag&SPPWAIT) == 0 &&
287 		   (p->p_sigignore & sigmask(SIGTTOU)) == 0 &&
288 		   (p->p_sigmask & sigmask(SIGTTOU)) == 0) {
289 			pgsignal(p->p_pgrp, SIGTTOU, 1);
290 			if (error = ttysleep(tp, (caddr_t)&lbolt,
291 			    TTOPRI | PCATCH, ttybg, 0))
292 				return (error);
293 		}
294 		break;
295 	}
296 
297 	/*
298 	 * Process the ioctl.
299 	 */
300 	switch (com) {
301 
302 	/* get discipline number */
303 	case TIOCGETD:
304 		*(int *)data = tp->t_line;
305 		break;
306 
307 	/* set line discipline */
308 	case TIOCSETD: {
309 		register int t = *(int *)data;
310 		dev_t dev = tp->t_dev;
311 
312 		if ((unsigned)t >= nldisp)
313 			return (ENXIO);
314 		if (t != tp->t_line) {
315 			s = spltty();
316 			(*linesw[tp->t_line].l_close)(tp);
317 			error = (*linesw[t].l_open)(dev, tp);
318 			if (error) {
319 				(void)(*linesw[tp->t_line].l_open)(dev, tp);
320 				splx(s);
321 				return (error);
322 			}
323 			tp->t_line = t;
324 			splx(s);
325 		}
326 		break;
327 	}
328 
329 	/* prevent more opens on channel */
330 	case TIOCEXCL:
331 		tp->t_state |= TS_XCLUDE;
332 		break;
333 
334 	case TIOCNXCL:
335 		tp->t_state &= ~TS_XCLUDE;
336 		break;
337 
338 	case TIOCHPCL:
339 		tp->t_cflag |= HUPCL;
340 		break;
341 
342 	case TIOCFLUSH: {
343 		register int flags = *(int *)data;
344 
345 		if (flags == 0)
346 			flags = FREAD|FWRITE;
347 		else
348 			flags &= FREAD|FWRITE;
349 		ttyflush(tp, flags);
350 		break;
351 	}
352 
353 	case FIOASYNC:
354 		if (*(int *)data)
355 			tp->t_state |= TS_ASYNC;
356 		else
357 			tp->t_state &= ~TS_ASYNC;
358 		break;
359 
360 	case FIONBIO:
361 		break;	/* XXX remove */
362 
363 	/* return number of characters immediately available */
364 	case FIONREAD:
365 		*(off_t *)data = ttnread(tp);
366 		break;
367 
368 	case TIOCOUTQ:
369 		*(int *)data = tp->t_outq.c_cc;
370 		break;
371 
372 	case TIOCSTOP:
373 		s = spltty();
374 		if ((tp->t_state&TS_TTSTOP) == 0) {
375 			tp->t_state |= TS_TTSTOP;
376 			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
377 		}
378 		splx(s);
379 		break;
380 
381 	case TIOCSTART:
382 		s = spltty();
383 		if ((tp->t_state&TS_TTSTOP) || (tp->t_lflag&FLUSHO)) {
384 			tp->t_state &= ~TS_TTSTOP;
385 			tp->t_lflag &= ~FLUSHO;
386 			ttstart(tp);
387 		}
388 		splx(s);
389 		break;
390 
391 	/*
392 	 * Simulate typing of a character at the terminal.
393 	 */
394 	case TIOCSTI:
395 		if (p->p_ucred->cr_uid && (flag & FREAD) == 0)
396 			return (EPERM);
397 		if (p->p_ucred->cr_uid && !isctty(p, tp))
398 			return (EACCES);
399 		(*linesw[tp->t_line].l_rint)(*(char *)data, tp);
400 		break;
401 
402 	case TIOCGETA: {
403 		struct termios *t = (struct termios *)data;
404 
405 		bcopy(&tp->t_termios, t, sizeof(struct termios));
406 		break;
407 	}
408 
409 	case TIOCSETA:
410 	case TIOCSETAW:
411 	case TIOCSETAF: {
412 		register struct termios *t = (struct termios *)data;
413 
414 		s = spltty();
415 		if (com == TIOCSETAW || com == TIOCSETAF) {
416 			if (error = ttywait(tp)) {
417 				splx(s);
418 				return (error);
419 			}
420 			if (com == TIOCSETAF)
421 				ttyflush(tp, FREAD);
422 		}
423 		if ((t->c_cflag&CIGNORE) == 0) {
424 			/*
425 			 * set device hardware
426 			 */
427 			if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
428 				splx(s);
429 				return (error);
430 			} else {
431 				if ((tp->t_state&TS_CARR_ON) == 0 &&
432 				    (tp->t_cflag&CLOCAL) &&
433 				    (t->c_cflag&CLOCAL) == 0) {
434 					tp->t_state &= ~TS_ISOPEN;
435 					tp->t_state |= TS_WOPEN;
436 					ttwakeup(tp);
437 				}
438 				tp->t_cflag = t->c_cflag;
439 				tp->t_ispeed = t->c_ispeed;
440 				tp->t_ospeed = t->c_ospeed;
441 			}
442 			ttsetwater(tp);
443 		}
444 		if (com != TIOCSETAF) {
445 			if ((t->c_lflag&ICANON) != (tp->t_lflag&ICANON))
446 				if (t->c_lflag&ICANON) {
447 					tp->t_lflag |= PENDIN;
448 					ttwakeup(tp);
449 				}
450 				else {
451 					struct clist tq;
452 
453 					catq(&tp->t_rawq, &tp->t_canq);
454 					tq = tp->t_rawq;
455 					tp->t_rawq = tp->t_canq;
456 					tp->t_canq = tq;
457 				}
458 		}
459 		tp->t_iflag = t->c_iflag;
460 		tp->t_oflag = t->c_oflag;
461 		/*
462 		 * Make the EXTPROC bit read only.
463 		 */
464 		if (tp->t_lflag&EXTPROC)
465 			t->c_lflag |= EXTPROC;
466 		else
467 			t->c_lflag &= ~EXTPROC;
468 		tp->t_lflag = t->c_lflag;
469 		bcopy(t->c_cc, tp->t_cc, sizeof(t->c_cc));
470 		splx(s);
471 		break;
472 	}
473 
474 	/*
475 	 * Set controlling terminal.
476 	 * Session ctty vnode pointer set in vnode layer.
477 	 */
478 	case TIOCSCTTY:
479 		if (!SESS_LEADER(p) ||
480 		   (p->p_session->s_ttyvp || tp->t_session) &&
481 		   (tp->t_session != p->p_session))
482 			return (EPERM);
483 		tp->t_session = p->p_session;
484 		tp->t_pgrp = p->p_pgrp;
485 		p->p_session->s_ttyp = tp;
486 		p->p_flag |= SCTTY;
487 		break;
488 
489 	/*
490 	 * Set terminal process group.
491 	 */
492 	case TIOCSPGRP: {
493 		register struct pgrp *pgrp = pgfind(*(int *)data);
494 
495 		if (!isctty(p, tp))
496 			return (ENOTTY);
497 		else if (pgrp == NULL || pgrp->pg_session != p->p_session)
498 			return (EPERM);
499 		tp->t_pgrp = pgrp;
500 		break;
501 	}
502 
503 	case TIOCGPGRP:
504 		if (!isctty(p, tp))
505 			return (ENOTTY);
506 		*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PID;
507 		break;
508 
509 	case TIOCSWINSZ:
510 		if (bcmp((caddr_t)&tp->t_winsize, data,
511 		    sizeof (struct winsize))) {
512 			tp->t_winsize = *(struct winsize *)data;
513 			pgsignal(tp->t_pgrp, SIGWINCH, 1);
514 		}
515 		break;
516 
517 	case TIOCGWINSZ:
518 		*(struct winsize *)data = tp->t_winsize;
519 		break;
520 
521 	case TIOCCONS:
522 		if (*(int *)data) {
523 			if (constty && constty != tp &&
524 			    (constty->t_state & (TS_CARR_ON|TS_ISOPEN)) ==
525 			    (TS_CARR_ON|TS_ISOPEN))
526 				return (EBUSY);
527 #ifndef	UCONSOLE
528 			if (error = suser(p->p_ucred, &p->p_acflag))
529 				return (error);
530 #endif
531 			constty = tp;
532 		} else if (tp == constty)
533 			constty = NULL;
534 		break;
535 
536 	case TIOCDRAIN:
537 		if (error = ttywait(tp))
538 			return (error);
539 		break;
540 
541 	default:
542 #ifdef COMPAT_43
543 		return (ttcompat(tp, com, data, flag));
544 #else
545 		return (-1);
546 #endif
547 	}
548 	return (0);
549 }
550 
551 ttnread(tp)
552 	struct tty *tp;
553 {
554 	int nread = 0;
555 
556 	if (tp->t_lflag & PENDIN)
557 		ttypend(tp);
558 	nread = tp->t_canq.c_cc;
559 	if ((tp->t_lflag & ICANON) == 0)
560 		nread += tp->t_rawq.c_cc;
561 	return (nread);
562 }
563 
564 ttselect(dev, rw)
565 	dev_t dev;
566 	int rw;
567 {
568 	register struct tty *tp = &cdevsw[major(dev)].d_ttys[minor(dev)];
569 	int nread;
570 	int s = spltty();
571 
572 	switch (rw) {
573 
574 	case FREAD:
575 		nread = ttnread(tp);
576 		if (nread > 0 ||
577 		   ((tp->t_cflag&CLOCAL) == 0 && (tp->t_state&TS_CARR_ON) == 0))
578 			goto win;
579 		if (tp->t_rsel && tp->t_rsel->p_wchan == (caddr_t)&selwait)
580 			tp->t_state |= TS_RCOLL;
581 		else
582 			tp->t_rsel = curproc;
583 		break;
584 
585 	case FWRITE:
586 		if (tp->t_outq.c_cc <= tp->t_lowat)
587 			goto win;
588 		if (tp->t_wsel && tp->t_wsel->p_wchan == (caddr_t)&selwait)
589 			tp->t_state |= TS_WCOLL;
590 		else
591 			tp->t_wsel = curproc;
592 		break;
593 	}
594 	splx(s);
595 	return (0);
596 win:
597 	splx(s);
598 	return (1);
599 }
600 
601 /*
602  * Initial open of tty, or (re)entry to standard tty line discipline.
603  */
604 ttyopen(dev, tp)
605 	dev_t dev;
606 	register struct tty *tp;
607 {
608 
609 	tp->t_dev = dev;
610 
611 	tp->t_state &= ~TS_WOPEN;
612 	if ((tp->t_state & TS_ISOPEN) == 0) {
613 		tp->t_state |= TS_ISOPEN;
614 		bzero((caddr_t)&tp->t_winsize, sizeof(tp->t_winsize));
615 	}
616 	return (0);
617 }
618 
619 /*
620  * "close" a line discipline
621  */
622 ttylclose(tp)
623 	register struct tty *tp;
624 {
625 
626 	ttywflush(tp);
627 }
628 
629 /*
630  * Handle close() on a tty line: flush and set to initial state,
631  * bumping generation number so that pending read/write calls
632  * can detect recycling of the tty.
633  */
634 ttyclose(tp)
635 	register struct tty *tp;
636 {
637 	if (constty == tp)
638 		constty = NULL;
639 	ttyflush(tp, FREAD|FWRITE);
640 	tp->t_session = NULL;
641 	tp->t_pgrp = NULL;
642 	tp->t_state = 0;
643 	tp->t_gen++;
644 	return (0);
645 }
646 
647 /*
648  * Handle modem control transition on a tty.
649  * Flag indicates new state of carrier.
650  * Returns 0 if the line should be turned off, otherwise 1.
651  */
652 ttymodem(tp, flag)
653 	register struct tty *tp;
654 {
655 
656 	if ((tp->t_state&TS_WOPEN) == 0 && (tp->t_lflag&MDMBUF)) {
657 		/*
658 		 * MDMBUF: do flow control according to carrier flag
659 		 */
660 		if (flag) {
661 			tp->t_state &= ~TS_TTSTOP;
662 			ttstart(tp);
663 		} else if ((tp->t_state&TS_TTSTOP) == 0) {
664 			tp->t_state |= TS_TTSTOP;
665 			(*cdevsw[major(tp->t_dev)].d_stop)(tp, 0);
666 		}
667 	} else if (flag == 0) {
668 		/*
669 		 * Lost carrier.
670 		 */
671 		tp->t_state &= ~TS_CARR_ON;
672 		if (tp->t_state&TS_ISOPEN && (tp->t_cflag&CLOCAL) == 0) {
673 			if (tp->t_session && tp->t_session->s_leader)
674 				psignal(tp->t_session->s_leader, SIGHUP);
675 			ttyflush(tp, FREAD|FWRITE);
676 			return (0);
677 		}
678 	} else {
679 		/*
680 		 * Carrier now on.
681 		 */
682 		tp->t_state |= TS_CARR_ON;
683 		ttwakeup(tp);
684 	}
685 	return (1);
686 }
687 
688 /*
689  * Default modem control routine (for other line disciplines).
690  * Return argument flag, to turn off device on carrier drop.
691  */
692 nullmodem(tp, flag)
693 	register struct tty *tp;
694 	int flag;
695 {
696 
697 	if (flag)
698 		tp->t_state |= TS_CARR_ON;
699 	else {
700 		tp->t_state &= ~TS_CARR_ON;
701 		if ((tp->t_cflag&CLOCAL) == 0) {
702 			if (tp->t_session && tp->t_session->s_leader)
703 				psignal(tp->t_session->s_leader, SIGHUP);
704 			return (0);
705 		}
706 	}
707 	return (1);
708 }
709 
710 /*
711  * reinput pending characters after state switch
712  * call at spltty().
713  */
714 ttypend(tp)
715 	register struct tty *tp;
716 {
717 	struct clist tq;
718 	register c;
719 
720 	tp->t_lflag &= ~PENDIN;
721 	tp->t_state |= TS_TYPEN;
722 	tq = tp->t_rawq;
723 	tp->t_rawq.c_cc = 0;
724 	tp->t_rawq.c_cf = tp->t_rawq.c_cl = 0;
725 	while ((c = getc(&tq)) >= 0)
726 		ttyinput(c, tp);
727 	tp->t_state &= ~TS_TYPEN;
728 }
729 
730 /*
731  * Process input of a single character received on a tty.
732  */
733 ttyinput(c, tp)
734 	register c;
735 	register struct tty *tp;
736 {
737 	register int iflag = tp->t_iflag;
738 	register int lflag = tp->t_lflag;
739 	register u_char *cc = tp->t_cc;
740 	int i, err;
741 
742 	/*
743 	 * If input is pending take it first.
744 	 */
745 	if (lflag&PENDIN)
746 		ttypend(tp);
747 	/*
748 	 * Gather stats.
749 	 */
750 	tk_nin++;
751 	if (lflag&ICANON) {
752 		tk_cancc++;
753 		tp->t_cancc++;
754 	} else {
755 		tk_rawcc++;
756 		tp->t_rawcc++;
757 	}
758 	/*
759 	 * Handle exceptional conditions (break, parity, framing).
760 	 */
761 	if (err = (c&TTY_ERRORMASK)) {
762 		c &= ~TTY_ERRORMASK;
763 		if (err&TTY_FE && !c) {		/* break */
764 			if (iflag&IGNBRK)
765 				goto endcase;
766 			else if (iflag&BRKINT && lflag&ISIG &&
767 				(cc[VINTR] != _POSIX_VDISABLE))
768 				c = cc[VINTR];
769 			else if (iflag&PARMRK)
770 				goto parmrk;
771 		} else if ((err&TTY_PE && iflag&INPCK) || err&TTY_FE) {
772 			if (iflag&IGNPAR)
773 				goto endcase;
774 			else if (iflag&PARMRK) {
775 parmrk:
776 				putc(0377|TTY_QUOTE, &tp->t_rawq);
777 				putc(0|TTY_QUOTE, &tp->t_rawq);
778 				putc(c|TTY_QUOTE, &tp->t_rawq);
779 				goto endcase;
780 			} else
781 				c = 0;
782 		}
783 	}
784 	/*
785 	 * In tandem mode, check high water mark.
786 	 */
787 	if (iflag&IXOFF)
788 		ttyblock(tp);
789 	if ((tp->t_state&TS_TYPEN) == 0 && (iflag&ISTRIP))
790 		c &= ~0x80;
791 	if ((tp->t_lflag&EXTPROC) == 0) {
792 		/*
793 		 * Check for literal nexting very first
794 		 */
795 		if (tp->t_state&TS_LNCH) {
796 			c |= TTY_QUOTE;
797 			tp->t_state &= ~TS_LNCH;
798 		}
799 		/*
800 		 * Scan for special characters.  This code
801 		 * is really just a big case statement with
802 		 * non-constant cases.  The bottom of the
803 		 * case statement is labeled ``endcase'', so goto
804 		 * it after a case match, or similar.
805 		 */
806 
807 		/*
808 		 * Control chars which aren't controlled
809 		 * by ICANON, ISIG, or IXON.
810 		 */
811 		if (lflag&IEXTEN) {
812 			if (CCEQ(cc[VLNEXT], c)) {
813 				if (lflag&ECHO) {
814 					if (lflag&ECHOE)
815 						ttyoutstr("^\b", tp);
816 					else
817 						ttyecho(c, tp);
818 				}
819 				tp->t_state |= TS_LNCH;
820 				goto endcase;
821 			}
822 			if (CCEQ(cc[VDISCARD], c)) {
823 				if (lflag&FLUSHO)
824 					tp->t_lflag &= ~FLUSHO;
825 				else {
826 					ttyflush(tp, FWRITE);
827 					ttyecho(c, tp);
828 					if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
829 						ttyretype(tp);
830 					tp->t_lflag |= FLUSHO;
831 				}
832 				goto startoutput;
833 			}
834 		}
835 		/*
836 		 * Signals.
837 		 */
838 		if (lflag&ISIG) {
839 			if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
840 				if ((lflag&NOFLSH) == 0)
841 					ttyflush(tp, FREAD|FWRITE);
842 				ttyecho(c, tp);
843 				pgsignal(tp->t_pgrp,
844 				    CCEQ(cc[VINTR], c) ? SIGINT : SIGQUIT, 1);
845 				goto endcase;
846 			}
847 			if (CCEQ(cc[VSUSP], c)) {
848 				if ((lflag&NOFLSH) == 0)
849 					ttyflush(tp, FREAD);
850 				ttyecho(c, tp);
851 				pgsignal(tp->t_pgrp, SIGTSTP, 1);
852 				goto endcase;
853 			}
854 		}
855 		/*
856 		 * Handle start/stop characters.
857 		 */
858 		if (iflag&IXON) {
859 			if (CCEQ(cc[VSTOP], c)) {
860 				if ((tp->t_state&TS_TTSTOP) == 0) {
861 					tp->t_state |= TS_TTSTOP;
862 					(*cdevsw[major(tp->t_dev)].d_stop)(tp,
863 					   0);
864 					return;
865 				}
866 				if (!CCEQ(cc[VSTART], c))
867 					return;
868 				/*
869 				 * if VSTART == VSTOP then toggle
870 				 */
871 				goto endcase;
872 			}
873 			if (CCEQ(cc[VSTART], c))
874 				goto restartoutput;
875 		}
876 		/*
877 		 * IGNCR, ICRNL, & INLCR
878 		 */
879 		if (c == '\r') {
880 			if (iflag&IGNCR)
881 				goto endcase;
882 			else if (iflag&ICRNL)
883 				c = '\n';
884 		} else if (c == '\n' && iflag&INLCR)
885 			c = '\r';
886 	}
887 	if ((tp->t_lflag&EXTPROC) == 0 && lflag&ICANON) {
888 		/*
889 		 * From here on down canonical mode character
890 		 * processing takes place.
891 		 */
892 		/*
893 		 * erase (^H / ^?)
894 		 */
895 		if (CCEQ(cc[VERASE], c)) {
896 			if (tp->t_rawq.c_cc)
897 				ttyrub(unputc(&tp->t_rawq), tp);
898 			goto endcase;
899 		}
900 		/*
901 		 * kill (^U)
902 		 */
903 		if (CCEQ(cc[VKILL], c)) {
904 			if (lflag&ECHOKE && tp->t_rawq.c_cc == tp->t_rocount &&
905 			    (lflag&ECHOPRT) == 0) {
906 				while (tp->t_rawq.c_cc)
907 					ttyrub(unputc(&tp->t_rawq), tp);
908 			} else {
909 				ttyecho(c, tp);
910 				if (lflag&ECHOK || lflag&ECHOKE)
911 					ttyecho('\n', tp);
912 				while (getc(&tp->t_rawq) > 0)
913 					;
914 				tp->t_rocount = 0;
915 			}
916 			tp->t_state &= ~TS_LOCAL;
917 			goto endcase;
918 		}
919 		/*
920 		 * word erase (^W)
921 		 */
922 		if (CCEQ(cc[VWERASE], c)) {
923 			int ctype;
924 			int alt = lflag&ALTWERASE;
925 
926 			/*
927 			 * erase whitespace
928 			 */
929 			while ((c = unputc(&tp->t_rawq)) == ' ' || c == '\t')
930 				ttyrub(c, tp);
931 			if (c == -1)
932 				goto endcase;
933 			/*
934 			 * erase last char of word and remember the
935 			 * next chars type (for ALTWERASE)
936 			 */
937 			ttyrub(c, tp);
938 			c = unputc(&tp->t_rawq);
939 			if (c == -1)
940 				goto endcase;
941 			ctype = ISALPHA(c);
942 			/*
943 			 * erase rest of word
944 			 */
945 			do {
946 				ttyrub(c, tp);
947 				c = unputc(&tp->t_rawq);
948 				if (c == -1)
949 					goto endcase;
950 			} while (c != ' ' && c != '\t' &&
951 				(alt == 0 || ISALPHA(c) == ctype));
952 			(void) putc(c, &tp->t_rawq);
953 			goto endcase;
954 		}
955 		/*
956 		 * reprint line (^R)
957 		 */
958 		if (CCEQ(cc[VREPRINT], c)) {
959 			ttyretype(tp);
960 			goto endcase;
961 		}
962 		/*
963 		 * ^T - kernel info and generate SIGINFO
964 		 */
965 		if (CCEQ(cc[VSTATUS], c)) {
966 			pgsignal(tp->t_pgrp, SIGINFO, 1);
967 			if ((lflag&NOKERNINFO) == 0)
968 				ttyinfo(tp);
969 			goto endcase;
970 		}
971 	}
972 	/*
973 	 * Check for input buffer overflow
974 	 */
975 	if (tp->t_rawq.c_cc + tp->t_canq.c_cc >= TTYHOG) {
976 		if (iflag&IMAXBEL) {
977 			if (tp->t_outq.c_cc < tp->t_hiwat)
978 				(void) ttyoutput(CTRL('g'), tp);
979 		} else
980 			ttyflush(tp, FREAD | FWRITE);
981 		goto endcase;
982 	}
983 	/*
984 	 * Put data char in q for user and
985 	 * wakeup on seeing a line delimiter.
986 	 */
987 	if (putc(c, &tp->t_rawq) >= 0) {
988 		if ((lflag&ICANON) == 0) {
989 			ttwakeup(tp);
990 			ttyecho(c, tp);
991 			goto endcase;
992 		}
993 		if (ttbreakc(c)) {
994 			tp->t_rocount = 0;
995 			catq(&tp->t_rawq, &tp->t_canq);
996 			ttwakeup(tp);
997 		} else if (tp->t_rocount++ == 0)
998 			tp->t_rocol = tp->t_col;
999 		if (tp->t_state&TS_ERASE) {
1000 			/*
1001 			 * end of prterase \.../
1002 			 */
1003 			tp->t_state &= ~TS_ERASE;
1004 			(void) ttyoutput('/', tp);
1005 		}
1006 		i = tp->t_col;
1007 		ttyecho(c, tp);
1008 		if (CCEQ(cc[VEOF], c) && lflag&ECHO) {
1009 			/*
1010 			 * Place the cursor over the '^' of the ^D.
1011 			 */
1012 			i = MIN(2, tp->t_col - i);
1013 			while (i > 0) {
1014 				(void) ttyoutput('\b', tp);
1015 				i--;
1016 			}
1017 		}
1018 	}
1019 endcase:
1020 	/*
1021 	 * IXANY means allow any character to restart output.
1022 	 */
1023 	if ((tp->t_state&TS_TTSTOP) && (iflag&IXANY) == 0 &&
1024 	    cc[VSTART] != cc[VSTOP])
1025 		return;
1026 restartoutput:
1027 	tp->t_state &= ~TS_TTSTOP;
1028 	tp->t_lflag &= ~FLUSHO;
1029 startoutput:
1030 	ttstart(tp);
1031 }
1032 
1033 /*
1034  * Output a single character on a tty, doing output processing
1035  * as needed (expanding tabs, newline processing, etc.).
1036  * Returns < 0 if putc succeeds, otherwise returns char to resend.
1037  * Must be recursive.
1038  */
1039 ttyoutput(c, tp)
1040 	register c;
1041 	register struct tty *tp;
1042 {
1043 	register int col;
1044 	register long oflag = tp->t_oflag;
1045 
1046 	if ((oflag&OPOST) == 0) {
1047 		if (tp->t_lflag&FLUSHO)
1048 			return (-1);
1049 		if (putc(c, &tp->t_outq))
1050 			return (c);
1051 		tk_nout++;
1052 		tp->t_outcc++;
1053 		return (-1);
1054 	}
1055 	c &= TTY_CHARMASK;
1056 	/*
1057 	 * Do tab expansion if OXTABS is set.
1058 	 * Special case if we have external processing, we don't
1059 	 * do the tab expansion because we'll probably get it
1060 	 * wrong.  If tab expansion needs to be done, let it
1061 	 * happen externally.
1062 	 */
1063 	if (c == '\t' && oflag&OXTABS && (tp->t_lflag&EXTPROC) == 0) {
1064 		register int s;
1065 
1066 		c = 8 - (tp->t_col&7);
1067 		if ((tp->t_lflag&FLUSHO) == 0) {
1068 			s = spltty();		/* don't interrupt tabs */
1069 			c -= b_to_q("        ", c, &tp->t_outq);
1070 			tk_nout += c;
1071 			tp->t_outcc += c;
1072 			splx(s);
1073 		}
1074 		tp->t_col += c;
1075 		return (c ? -1 : '\t');
1076 	}
1077 	if (c == CEOT && oflag&ONOEOT)
1078 		return (-1);
1079 	tk_nout++;
1080 	tp->t_outcc++;
1081 	/*
1082 	 * Newline translation: if ONLCR is set,
1083 	 * translate newline into "\r\n".
1084 	 */
1085 	if (c == '\n' && (tp->t_oflag&ONLCR) && ttyoutput('\r', tp) >= 0)
1086 		return (c);
1087 	if ((tp->t_lflag&FLUSHO) == 0 && putc(c, &tp->t_outq))
1088 		return (c);
1089 
1090 	col = tp->t_col;
1091 	switch (CCLASS(c)) {
1092 
1093 	case ORDINARY:
1094 		col++;
1095 
1096 	case CONTROL:
1097 		break;
1098 
1099 	case BACKSPACE:
1100 		if (col > 0)
1101 			col--;
1102 		break;
1103 
1104 	case NEWLINE:
1105 		col = 0;
1106 		break;
1107 
1108 	case TAB:
1109 		col = (col + 8) &~ 0x7;
1110 		break;
1111 
1112 	case RETURN:
1113 		col = 0;
1114 	}
1115 	tp->t_col = col;
1116 	return (-1);
1117 }
1118 
1119 /*
1120  * Process a read call on a tty device.
1121  */
1122 ttread(tp, uio, flag)
1123 	register struct tty *tp;
1124 	struct uio *uio;
1125 {
1126 	register struct clist *qp;
1127 	register int c;
1128 	register long lflag;
1129 	register u_char *cc = tp->t_cc;
1130 	register struct proc *p = curproc;
1131 	int s, first, error = 0;
1132 
1133 loop:
1134 	lflag = tp->t_lflag;
1135 	s = spltty();
1136 	/*
1137 	 * take pending input first
1138 	 */
1139 	if (lflag&PENDIN)
1140 		ttypend(tp);
1141 	splx(s);
1142 
1143 	/*
1144 	 * Hang process if it's in the background.
1145 	 */
1146 	if (isbackground(p, tp)) {
1147 		if ((p->p_sigignore & sigmask(SIGTTIN)) ||
1148 		   (p->p_sigmask & sigmask(SIGTTIN)) ||
1149 		    p->p_flag&SPPWAIT || p->p_pgrp->pg_jobc == 0)
1150 			return (EIO);
1151 		pgsignal(p->p_pgrp, SIGTTIN, 1);
1152 		if (error = ttysleep(tp, (caddr_t)&lbolt, TTIPRI | PCATCH,
1153 		    ttybg, 0))
1154 			return (error);
1155 		goto loop;
1156 	}
1157 
1158 	/*
1159 	 * If canonical, use the canonical queue,
1160 	 * else use the raw queue.
1161 	 *
1162 	 * (should get rid of clists...)
1163 	 */
1164 	qp = lflag&ICANON ? &tp->t_canq : &tp->t_rawq;
1165 
1166 	/*
1167 	 * If there is no input, sleep on rawq
1168 	 * awaiting hardware receipt and notification.
1169 	 * If we have data, we don't need to check for carrier.
1170 	 */
1171 	s = spltty();
1172 	if (qp->c_cc <= 0) {
1173 		int carrier;
1174 
1175 		carrier = (tp->t_state&TS_CARR_ON) || (tp->t_cflag&CLOCAL);
1176 		if (!carrier && tp->t_state&TS_ISOPEN) {
1177 			splx(s);
1178 			return (0);	/* EOF */
1179 		}
1180 		if (flag & IO_NDELAY) {
1181 			splx(s);
1182 			return (EWOULDBLOCK);
1183 		}
1184 		error = ttysleep(tp, (caddr_t)&tp->t_rawq, TTIPRI | PCATCH,
1185 		    carrier ? ttyin : ttopen, 0);
1186 		splx(s);
1187 		if (error)
1188 			return (error);
1189 		goto loop;
1190 	}
1191 	splx(s);
1192 
1193 	/*
1194 	 * Input present, check for input mapping and processing.
1195 	 */
1196 	first = 1;
1197 	while ((c = getc(qp)) >= 0) {
1198 		/*
1199 		 * delayed suspend (^Y)
1200 		 */
1201 		if (CCEQ(cc[VDSUSP], c) && lflag&ISIG) {
1202 			pgsignal(tp->t_pgrp, SIGTSTP, 1);
1203 			if (first) {
1204 				if (error = ttysleep(tp, (caddr_t)&lbolt,
1205 				    TTIPRI | PCATCH, ttybg, 0))
1206 					break;
1207 				goto loop;
1208 			}
1209 			break;
1210 		}
1211 		/*
1212 		 * Interpret EOF only in canonical mode.
1213 		 */
1214 		if (CCEQ(cc[VEOF], c) && lflag&ICANON)
1215 			break;
1216 		/*
1217 		 * Give user character.
1218 		 */
1219  		error = ureadc(c, uio);
1220 		if (error)
1221 			break;
1222  		if (uio->uio_resid == 0)
1223 			break;
1224 		/*
1225 		 * In canonical mode check for a "break character"
1226 		 * marking the end of a "line of input".
1227 		 */
1228 		if (lflag&ICANON && ttbreakc(c))
1229 			break;
1230 		first = 0;
1231 	}
1232 	/*
1233 	 * Look to unblock output now that (presumably)
1234 	 * the input queue has gone down.
1235 	 */
1236 	if (tp->t_state&TS_TBLOCK && tp->t_rawq.c_cc < TTYHOG/5) {
1237 		if (cc[VSTART] != _POSIX_VDISABLE &&
1238 		    putc(cc[VSTART], &tp->t_outq) == 0) {
1239 			tp->t_state &= ~TS_TBLOCK;
1240 			ttstart(tp);
1241 		}
1242 	}
1243 	return (error);
1244 }
1245 
1246 /*
1247  * Check the output queue on tp for space for a kernel message
1248  * (from uprintf/tprintf).  Allow some space over the normal
1249  * hiwater mark so we don't lose messages due to normal flow
1250  * control, but don't let the tty run amok.
1251  * Sleeps here are not interruptible, but we return prematurely
1252  * if new signals come in.
1253  */
1254 ttycheckoutq(tp, wait)
1255 	register struct tty *tp;
1256 	int wait;
1257 {
1258 	int hiwat, s, oldsig;
1259 	extern int wakeup();
1260 
1261 	hiwat = tp->t_hiwat;
1262 	s = spltty();
1263 	oldsig = curproc->p_sig;
1264 	if (tp->t_outq.c_cc > hiwat + 200)
1265 		while (tp->t_outq.c_cc > hiwat) {
1266 			ttstart(tp);
1267 			if (wait == 0 || curproc->p_sig != oldsig) {
1268 				splx(s);
1269 				return (0);
1270 			}
1271 			timeout(wakeup, (caddr_t)&tp->t_outq, hz);
1272 			tp->t_state |= TS_ASLEEP;
1273 			sleep((caddr_t)&tp->t_outq, PZERO - 1);
1274 		}
1275 	splx(s);
1276 	return (1);
1277 }
1278 
1279 /*
1280  * Process a write call on a tty device.
1281  */
1282 ttwrite(tp, uio, flag)
1283 	register struct tty *tp;
1284 	register struct uio *uio;
1285 {
1286 	register char *cp;
1287 	register int cc = 0, ce;
1288 	register struct proc *p = curproc;
1289 	int i, hiwat, cnt, error, s;
1290 	char obuf[OBUFSIZ];
1291 
1292 	hiwat = tp->t_hiwat;
1293 	cnt = uio->uio_resid;
1294 	error = 0;
1295 loop:
1296 	s = spltty();
1297 	if ((tp->t_state&TS_CARR_ON) == 0 && (tp->t_cflag&CLOCAL) == 0) {
1298 		if (tp->t_state&TS_ISOPEN) {
1299 			splx(s);
1300 			return (EIO);
1301 		} else if (flag & IO_NDELAY) {
1302 			splx(s);
1303 			error = EWOULDBLOCK;
1304 			goto out;
1305 		} else {
1306 			/*
1307 			 * sleep awaiting carrier
1308 			 */
1309 			error = ttysleep(tp, (caddr_t)&tp->t_rawq,
1310 					TTIPRI | PCATCH,ttopen, 0);
1311 			splx(s);
1312 			if (error)
1313 				goto out;
1314 			goto loop;
1315 		}
1316 	}
1317 	splx(s);
1318 	/*
1319 	 * Hang the process if it's in the background.
1320 	 */
1321 	if (isbackground(p, tp) &&
1322 	    tp->t_lflag&TOSTOP && (p->p_flag&SPPWAIT) == 0 &&
1323 	    (p->p_sigignore & sigmask(SIGTTOU)) == 0 &&
1324 	    (p->p_sigmask & sigmask(SIGTTOU)) == 0 &&
1325 	     p->p_pgrp->pg_jobc) {
1326 		pgsignal(p->p_pgrp, SIGTTOU, 1);
1327 		if (error = ttysleep(tp, (caddr_t)&lbolt, TTIPRI | PCATCH,
1328 		    ttybg, 0))
1329 			goto out;
1330 		goto loop;
1331 	}
1332 	/*
1333 	 * Process the user's data in at most OBUFSIZ
1334 	 * chunks.  Perform any output translation.
1335 	 * Keep track of high water mark, sleep on overflow
1336 	 * awaiting device aid in acquiring new space.
1337 	 */
1338 	while (uio->uio_resid > 0 || cc > 0) {
1339 		if (tp->t_lflag&FLUSHO) {
1340 			uio->uio_resid = 0;
1341 			return (0);
1342 		}
1343 		if (tp->t_outq.c_cc > hiwat)
1344 			goto ovhiwat;
1345 		/*
1346 		 * Grab a hunk of data from the user,
1347 		 * unless we have some leftover from last time.
1348 		 */
1349 		if (cc == 0) {
1350 			cc = min(uio->uio_resid, OBUFSIZ);
1351 			cp = obuf;
1352 			error = uiomove(cp, cc, uio);
1353 			if (error) {
1354 				cc = 0;
1355 				break;
1356 			}
1357 		}
1358 		/*
1359 		 * If nothing fancy need be done, grab those characters we
1360 		 * can handle without any of ttyoutput's processing and
1361 		 * just transfer them to the output q.  For those chars
1362 		 * which require special processing (as indicated by the
1363 		 * bits in partab), call ttyoutput.  After processing
1364 		 * a hunk of data, look for FLUSHO so ^O's will take effect
1365 		 * immediately.
1366 		 */
1367 		while (cc > 0) {
1368 			if ((tp->t_oflag&OPOST) == 0)
1369 				ce = cc;
1370 			else {
1371 				ce = cc - scanc((unsigned)cc, (u_char *)cp,
1372 				   (u_char *)partab, CCLASSMASK);
1373 				/*
1374 				 * If ce is zero, then we're processing
1375 				 * a special character through ttyoutput.
1376 				 */
1377 				if (ce == 0) {
1378 					tp->t_rocount = 0;
1379 					if (ttyoutput(*cp, tp) >= 0) {
1380 					    /* no c-lists, wait a bit */
1381 					    ttstart(tp);
1382 					    if (error = ttysleep(tp,
1383 						(caddr_t)&lbolt,
1384 						 TTOPRI | PCATCH, ttybuf, 0))
1385 						    break;
1386 					    goto loop;
1387 					}
1388 					cp++, cc--;
1389 					if ((tp->t_lflag&FLUSHO) ||
1390 					    tp->t_outq.c_cc > hiwat)
1391 						goto ovhiwat;
1392 					continue;
1393 				}
1394 			}
1395 			/*
1396 			 * A bunch of normal characters have been found,
1397 			 * transfer them en masse to the output queue and
1398 			 * continue processing at the top of the loop.
1399 			 * If there are any further characters in this
1400 			 * <= OBUFSIZ chunk, the first should be a character
1401 			 * requiring special handling by ttyoutput.
1402 			 */
1403 			tp->t_rocount = 0;
1404 			i = b_to_q(cp, ce, &tp->t_outq);
1405 			ce -= i;
1406 			tp->t_col += ce;
1407 			cp += ce, cc -= ce, tk_nout += ce;
1408 			tp->t_outcc += ce;
1409 			if (i > 0) {
1410 				/* out of c-lists, wait a bit */
1411 				ttstart(tp);
1412 				if (error = ttysleep(tp, (caddr_t)&lbolt,
1413 					    TTOPRI | PCATCH, ttybuf, 0))
1414 					break;
1415 				goto loop;
1416 			}
1417 			if (tp->t_lflag&FLUSHO || tp->t_outq.c_cc > hiwat)
1418 				break;
1419 		}
1420 		ttstart(tp);
1421 	}
1422 out:
1423 	/*
1424 	 * If cc is nonzero, we leave the uio structure inconsistent,
1425 	 * as the offset and iov pointers have moved forward,
1426 	 * but it doesn't matter (the call will either return short
1427 	 * or restart with a new uio).
1428 	 */
1429 	uio->uio_resid += cc;
1430 	return (error);
1431 
1432 ovhiwat:
1433 	ttstart(tp);
1434 	s = spltty();
1435 	/*
1436 	 * This can only occur if FLUSHO is set in t_lflag,
1437 	 * or if ttstart/oproc is synchronous (or very fast).
1438 	 */
1439 	if (tp->t_outq.c_cc <= hiwat) {
1440 		splx(s);
1441 		goto loop;
1442 	}
1443 	if (flag & IO_NDELAY) {
1444 		splx(s);
1445 		uio->uio_resid += cc;
1446 		if (uio->uio_resid == cnt)
1447 			return (EWOULDBLOCK);
1448 		return (0);
1449 	}
1450 	tp->t_state |= TS_ASLEEP;
1451 	error = ttysleep(tp, (caddr_t)&tp->t_outq, TTOPRI | PCATCH, ttyout, 0);
1452 	splx(s);
1453 	if (error)
1454 		goto out;
1455 	goto loop;
1456 }
1457 
1458 /*
1459  * Rubout one character from the rawq of tp
1460  * as cleanly as possible.
1461  */
1462 ttyrub(c, tp)
1463 	register c;
1464 	register struct tty *tp;
1465 {
1466 	register char *cp;
1467 	register int savecol;
1468 	int s;
1469 	char *nextc();
1470 
1471 	if ((tp->t_lflag&ECHO) == 0 || (tp->t_lflag&EXTPROC))
1472 		return;
1473 	tp->t_lflag &= ~FLUSHO;
1474 	if (tp->t_lflag&ECHOE) {
1475 		if (tp->t_rocount == 0) {
1476 			/*
1477 			 * Screwed by ttwrite; retype
1478 			 */
1479 			ttyretype(tp);
1480 			return;
1481 		}
1482 		if (c == ('\t'|TTY_QUOTE) || c == ('\n'|TTY_QUOTE))
1483 			ttyrubo(tp, 2);
1484 		else switch (CCLASS(c &= TTY_CHARMASK)) {
1485 
1486 		case ORDINARY:
1487 			ttyrubo(tp, 1);
1488 			break;
1489 
1490 		case VTAB:
1491 		case BACKSPACE:
1492 		case CONTROL:
1493 		case RETURN:
1494 		case NEWLINE:
1495 			if (tp->t_lflag&ECHOCTL)
1496 				ttyrubo(tp, 2);
1497 			break;
1498 
1499 		case TAB: {
1500 			int c;
1501 
1502 			if (tp->t_rocount < tp->t_rawq.c_cc) {
1503 				ttyretype(tp);
1504 				return;
1505 			}
1506 			s = spltty();
1507 			savecol = tp->t_col;
1508 			tp->t_state |= TS_CNTTB;
1509 			tp->t_lflag |= FLUSHO;
1510 			tp->t_col = tp->t_rocol;
1511 			cp = tp->t_rawq.c_cf;
1512 			if (cp)
1513 				c = *cp;	/* XXX FIX NEXTC */
1514 			for (; cp; cp = nextc(&tp->t_rawq, cp, &c))
1515 				ttyecho(c, tp);
1516 			tp->t_lflag &= ~FLUSHO;
1517 			tp->t_state &= ~TS_CNTTB;
1518 			splx(s);
1519 			/*
1520 			 * savecol will now be length of the tab
1521 			 */
1522 			savecol -= tp->t_col;
1523 			tp->t_col += savecol;
1524 			if (savecol > 8)
1525 				savecol = 8;		/* overflow screw */
1526 			while (--savecol >= 0)
1527 				(void) ttyoutput('\b', tp);
1528 			break;
1529 		}
1530 
1531 		default:
1532 			/* XXX */
1533 			printf("ttyrub: would panic c = %d, val = %d\n",
1534 				c, CCLASS(c));
1535 			/*panic("ttyrub");*/
1536 		}
1537 	} else if (tp->t_lflag&ECHOPRT) {
1538 		if ((tp->t_state&TS_ERASE) == 0) {
1539 			(void) ttyoutput('\\', tp);
1540 			tp->t_state |= TS_ERASE;
1541 		}
1542 		ttyecho(c, tp);
1543 	} else
1544 		ttyecho(tp->t_cc[VERASE], tp);
1545 	tp->t_rocount--;
1546 }
1547 
1548 /*
1549  * Crt back over cnt chars perhaps
1550  * erasing them.
1551  */
1552 ttyrubo(tp, cnt)
1553 	register struct tty *tp;
1554 	int cnt;
1555 {
1556 
1557 	while (--cnt >= 0)
1558 		ttyoutstr("\b \b", tp);
1559 }
1560 
1561 /*
1562  * Reprint the rawq line.
1563  * We assume c_cc has already been checked.
1564  */
1565 ttyretype(tp)
1566 	register struct tty *tp;
1567 {
1568 	register char *cp;
1569 	char *nextc();
1570 	int s, c;
1571 
1572 	if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
1573 		ttyecho(tp->t_cc[VREPRINT], tp);
1574 	(void) ttyoutput('\n', tp);
1575 	s = spltty();
1576 	/*** XXX *** FIX *** NEXTC IS BROKEN - DOESN'T CHECK QUOTE
1577 	  BIT OF FIRST CHAR ****/
1578 	for (cp = tp->t_canq.c_cf, c=(cp?*cp:0); cp; cp = nextc(&tp->t_canq, cp, &c)) {
1579 		ttyecho(c, tp);
1580 	}
1581 	for (cp = tp->t_rawq.c_cf, c=(cp?*cp:0); cp; cp = nextc(&tp->t_rawq, cp, &c)) {
1582 		ttyecho(c, tp);
1583 	}
1584 	tp->t_state &= ~TS_ERASE;
1585 	splx(s);
1586 	tp->t_rocount = tp->t_rawq.c_cc;
1587 	tp->t_rocol = 0;
1588 }
1589 
1590 /*
1591  * Echo a typed character to the terminal.
1592  */
1593 ttyecho(c, tp)
1594 	register c;
1595 	register struct tty *tp;
1596 {
1597 	if ((tp->t_state&TS_CNTTB) == 0)
1598 		tp->t_lflag &= ~FLUSHO;
1599 	if (((tp->t_lflag&ECHO) == 0 &&
1600 	    ((tp->t_lflag&ECHONL) == 0 || c == '\n')) || (tp->t_lflag&EXTPROC))
1601 		return;
1602 	if (tp->t_lflag&ECHOCTL) {
1603 		if ((c&TTY_CHARMASK) <= 037 && c != '\t' && c != '\n' ||
1604 		    c == 0177) {
1605 			(void) ttyoutput('^', tp);
1606 			c &= TTY_CHARMASK;
1607 			if (c == 0177)
1608 				c = '?';
1609 			else
1610 				c += 'A' - 1;
1611 		}
1612 	}
1613 	(void) ttyoutput(c, tp);
1614 }
1615 
1616 /*
1617  * send string cp to tp
1618  */
1619 ttyoutstr(cp, tp)
1620 	register char *cp;
1621 	register struct tty *tp;
1622 {
1623 	register char c;
1624 
1625 	while (c = *cp++)
1626 		(void) ttyoutput(c, tp);
1627 }
1628 
1629 /*
1630  * Wake up any readers on a tty.
1631  */
1632 ttwakeup(tp)
1633 	register struct tty *tp;
1634 {
1635 
1636 	if (tp->t_rsel) {
1637 		selwakeup(tp->t_rsel, tp->t_state&TS_RCOLL);
1638 		tp->t_state &= ~TS_RCOLL;
1639 		tp->t_rsel = 0;
1640 	}
1641 	if (tp->t_state & TS_ASYNC)
1642 		pgsignal(tp->t_pgrp, SIGIO, 1);
1643 	wakeup((caddr_t)&tp->t_rawq);
1644 }
1645 
1646 /*
1647  * Look up a code for a specified speed in a conversion table;
1648  * used by drivers to map software speed values to hardware parameters.
1649  */
1650 ttspeedtab(speed, table)
1651 	register struct speedtab *table;
1652 {
1653 
1654 	for ( ; table->sp_speed != -1; table++)
1655 		if (table->sp_speed == speed)
1656 			return (table->sp_code);
1657 	return (-1);
1658 }
1659 
1660 /*
1661  * set tty hi and low water marks
1662  *
1663  * Try to arrange the dynamics so there's about one second
1664  * from hi to low water.
1665  *
1666  */
1667 ttsetwater(tp)
1668 	struct tty *tp;
1669 {
1670 	register cps = tp->t_ospeed / 10;
1671 	register x;
1672 
1673 #define clamp(x, h, l) ((x)>h ? h : ((x)<l) ? l : (x))
1674 	tp->t_lowat = x = clamp(cps/2, TTMAXLOWAT, TTMINLOWAT);
1675 	x += cps;
1676 	x = clamp(x, TTMAXHIWAT, TTMINHIWAT);
1677 	tp->t_hiwat = roundup(x, CBSIZE);
1678 #undef clamp
1679 }
1680 
1681 /*
1682  * (^T)
1683  * Report on state of foreground process group.
1684  */
1685 ttyinfo(tp)
1686 	struct tty *tp;
1687 {
1688 	register struct proc *p, *pick = NULL;
1689 	int x, s;
1690 	struct timeval utime, stime;
1691 #define	pgtok(a)	(((a)*NBPG)/1024)
1692 
1693 	if (ttycheckoutq(tp,0) == 0)
1694 		return;
1695 	/*
1696 	 * load average
1697 	 */
1698 	x = (averunnable[0] * 100 + FSCALE/2) >> FSHIFT;
1699 	ttyprintf(tp, "load: %d.", x/100);
1700 	ttyoutint(x%100, 10, 2, tp);
1701 	if (tp->t_session == NULL)
1702 		ttyprintf(tp, " not a controlling terminal\n");
1703 	else if (tp->t_pgrp == NULL)
1704 		ttyprintf(tp, " no foreground process group\n");
1705 	else if ((p = tp->t_pgrp->pg_mem) == NULL)
1706 		ttyprintf(tp, " empty foreground process group\n");
1707 	else {
1708 		/* pick interesting process */
1709 		for (; p != NULL; p = p->p_pgrpnxt) {
1710 			if (proc_compare(pick, p))
1711 				pick = p;
1712 		}
1713 		ttyprintf(tp, "  cmd: %s %d [%s] ",
1714 			pick->p_comm, pick->p_pid,
1715 			pick->p_stat == SRUN ? "running" :
1716 			pick->p_wmesg ? pick->p_wmesg : "iowait");
1717 		/*
1718 		 * cpu time
1719 		 */
1720 		if (curproc == pick)
1721 			s = splclock();
1722 		utime = pick->p_utime;
1723 		stime = pick->p_stime;
1724 		if (curproc == pick)
1725 			splx(s);
1726 		/* user time */
1727 		x = (utime.tv_usec + 5000) / 10000; /* scale to 100's */
1728 		ttyoutint(utime.tv_sec, 10, 1, tp);
1729 		tputchar('.', tp);
1730 		ttyoutint(x, 10, 2, tp);
1731 		tputchar('u', tp);
1732 		tputchar(' ', tp);
1733 		/* system time */
1734 		x = (stime.tv_usec + 5000) / 10000; /* scale to 100's */
1735 		ttyoutint(stime.tv_sec, 10, 1, tp);
1736 		tputchar('.', tp);
1737 		ttyoutint(x, 10, 2, tp);
1738 		tputchar('s', tp);
1739 		tputchar(' ', tp);
1740 		/*
1741 		 * pctcpu
1742 		 */
1743 		x = pick->p_pctcpu * 10000 + FSCALE/2 >> FSHIFT;
1744 		ttyoutint(x/100, 10, 1, tp);
1745 #ifdef notdef	/* do we really want this ??? */
1746 		tputchar('.', tp);
1747 		ttyoutint(x%100, 10, 2, tp);
1748 #endif
1749 		ttyprintf(tp, "%% %dk\n", pgtok(pick->p_vmspace->vm_rssize));
1750 	}
1751 	tp->t_rocount = 0;	/* so pending input will be retyped if BS */
1752 }
1753 
1754 ttyoutint(n, base, min, tp)
1755 	register int n, base, min;
1756 	register struct tty *tp;
1757 {
1758 	char info[16];
1759 	register char *p = info;
1760 
1761 	while (--min >= 0 || n) {
1762 		*p++ = "0123456789abcdef"[n%base];
1763 		n /= base;
1764 	}
1765 	while (p > info)
1766 		ttyoutput(*--p, tp);
1767 }
1768 
1769 /*
1770  * Returns 1 if p2 is "better" than p1
1771  *
1772  * The algorithm for picking the "interesting" process is thus:
1773  *
1774  *	1) (Only foreground processes are eligable - implied)
1775  *	2) Runnable processes are favored over anything
1776  *	   else.  The runner with the highest cpu
1777  *	   utilization is picked (p_cpu).  Ties are
1778  *	   broken by picking the highest pid.
1779  *	3  Next, the sleeper with the shortest sleep
1780  *	   time is favored.  With ties, we pick out
1781  *	   just "short-term" sleepers (SSINTR == 0).
1782  *	   Further ties are broken by picking the highest
1783  *	   pid.
1784  *
1785  */
1786 #define isrun(p)	(((p)->p_stat == SRUN) || ((p)->p_stat == SIDL))
1787 #define TESTAB(a, b)    ((a)<<1 | (b))
1788 #define ONLYA   2
1789 #define ONLYB   1
1790 #define BOTH    3
1791 
1792 proc_compare(p1, p2)
1793 	register struct proc *p1, *p2;
1794 {
1795 
1796 	if (p1 == NULL)
1797 		return (1);
1798 	/*
1799 	 * see if at least one of them is runnable
1800 	 */
1801 	switch (TESTAB(isrun(p1), isrun(p2))) {
1802 	case ONLYA:
1803 		return (0);
1804 	case ONLYB:
1805 		return (1);
1806 	case BOTH:
1807 		/*
1808 		 * tie - favor one with highest recent cpu utilization
1809 		 */
1810 		if (p2->p_cpu > p1->p_cpu)
1811 			return (1);
1812 		if (p1->p_cpu > p2->p_cpu)
1813 			return (0);
1814 		return (p2->p_pid > p1->p_pid);	/* tie - return highest pid */
1815 	}
1816 	/*
1817  	 * weed out zombies
1818 	 */
1819 	switch (TESTAB(p1->p_stat == SZOMB, p2->p_stat == SZOMB)) {
1820 	case ONLYA:
1821 		return (1);
1822 	case ONLYB:
1823 		return (0);
1824 	case BOTH:
1825 		return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
1826 	}
1827 	/*
1828 	 * pick the one with the smallest sleep time
1829 	 */
1830 	if (p2->p_slptime > p1->p_slptime)
1831 		return (0);
1832 	if (p1->p_slptime > p2->p_slptime)
1833 		return (1);
1834 	/*
1835 	 * favor one sleeping in a non-interruptible sleep
1836 	 */
1837 	if (p1->p_flag&SSINTR && (p2->p_flag&SSINTR) == 0)
1838 		return (1);
1839 	if (p2->p_flag&SSINTR && (p1->p_flag&SSINTR) == 0)
1840 		return (0);
1841 	return (p2->p_pid > p1->p_pid);		/* tie - return highest pid */
1842 }
1843 
1844 /*
1845  * Output char to tty; console putchar style.
1846  */
1847 tputchar(c, tp)
1848 	int c;
1849 	struct tty *tp;
1850 {
1851 	register s = spltty();
1852 
1853 	if ((tp->t_state & (TS_CARR_ON|TS_ISOPEN)) == (TS_CARR_ON|TS_ISOPEN)) {
1854 		if (c == '\n')
1855 			(void) ttyoutput('\r', tp);
1856 		(void) ttyoutput(c, tp);
1857 		ttstart(tp);
1858 		splx(s);
1859 		return (0);
1860 	}
1861 	splx(s);
1862 	return (-1);
1863 }
1864 
1865 /*
1866  * Sleep on chan, returning ERESTART if tty changed
1867  * while we napped and returning any errors (e.g. EINTR/ETIMEDOUT)
1868  * reported by tsleep.  If the tty is revoked, restarting a pending
1869  * call will redo validation done at the start of the call.
1870  */
1871 ttysleep(tp, chan, pri, wmesg, timo)
1872 	struct tty *tp;
1873 	caddr_t chan;
1874 	int pri;
1875 	char *wmesg;
1876 	int timo;
1877 {
1878 	int error;
1879 	short gen = tp->t_gen;
1880 
1881 	if (error = tsleep(chan, pri, wmesg, timo))
1882 		return (error);
1883 	if (tp->t_gen != gen)
1884 		return (ERESTART);
1885 	return (0);
1886 }
1887