xref: /netbsd-src/sys/kern/tty.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
1 /*	$NetBSD: tty.c,v 1.208 2007/12/08 19:29:49 pooka Exp $	*/
2 
3 /*-
4  * Copyright (c) 1982, 1986, 1990, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)tty.c	8.13 (Berkeley) 1/9/95
37  */
38 
39 #include <sys/cdefs.h>
40 __KERNEL_RCSID(0, "$NetBSD: tty.c,v 1.208 2007/12/08 19:29:49 pooka Exp $");
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/ioctl.h>
45 #include <sys/proc.h>
46 #define	TTYDEFCHARS
47 #include <sys/tty.h>
48 #undef	TTYDEFCHARS
49 #include <sys/file.h>
50 #include <sys/conf.h>
51 #include <sys/dkstat.h>
52 #include <sys/uio.h>
53 #include <sys/kernel.h>
54 #include <sys/vnode.h>
55 #include <sys/syslog.h>
56 #include <sys/malloc.h>
57 #include <sys/pool.h>
58 #include <sys/signalvar.h>
59 #include <sys/resourcevar.h>
60 #include <sys/poll.h>
61 #include <sys/kprintf.h>
62 #include <sys/namei.h>
63 #include <sys/sysctl.h>
64 #include <sys/kauth.h>
65 #include <sys/intr.h>
66 
67 #include <machine/stdarg.h>
68 
69 static int	ttnread(struct tty *);
70 static void	ttyblock(struct tty *);
71 static void	ttyecho(int, struct tty *);
72 static void	ttyrubo(struct tty *, int);
73 static void	ttyprintf_nolock(struct tty *, const char *fmt, ...)
74     __attribute__((__format__(__printf__,2,3)));
75 static int	proc_compare(struct proc *, struct proc *);
76 static void	ttysigintr(void *);
77 
78 /* Symbolic sleep message strings. */
79 const char	ttclos[] = "ttycls";
80 const char	ttopen[] = "ttyopn";
81 const char	ttybg[] = "ttybg";
82 const char	ttyin[] = "ttyin";
83 const char	ttyout[] = "ttyout";
84 
85 /*
86  * Used to determine whether we still have a connection.  This is true in
87  * one of 3 cases:
88  * 1) We have carrier.
89  * 2) It's a locally attached terminal, and we are therefore ignoring carrier.
90  * 3) We're using a flow control mechanism that overloads the carrier signal.
91  */
92 #define	CONNECTED(tp)	(ISSET(tp->t_state, TS_CARR_ON) ||	\
93 			 ISSET(tp->t_cflag, CLOCAL | MDMBUF))
94 
95 /*
96  * Table with character classes and parity. The 8th bit indicates parity,
97  * the 7th bit indicates the character is an alphameric or underscore (for
98  * ALTWERASE), and the low 6 bits indicate delay type.  If the low 6 bits
99  * are 0 then the character needs no special processing on output; classes
100  * other than 0 might be translated or (not currently) require delays.
101  */
102 #define	E	0x00	/* Even parity. */
103 #define	O	0x80	/* Odd parity. */
104 #define	PARITY(c)	(char_type[c] & O)
105 
106 #define	ALPHA	0x40	/* Alpha or underscore. */
107 #define	ISALPHA(c)	(char_type[(c) & TTY_CHARMASK] & ALPHA)
108 
109 #define	CCLASSMASK	0x3f
110 #define	CCLASS(c)	(char_type[c] & CCLASSMASK)
111 
112 #define	BS	BACKSPACE
113 #define	CC	CONTROL
114 #define	CR	RETURN
115 #define	NA	ORDINARY | ALPHA
116 #define	NL	NEWLINE
117 #define	NO	ORDINARY
118 #define	TB	TAB
119 #define	VT	VTAB
120 
121 unsigned char const char_type[] = {
122 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* nul - bel */
123 	O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC,	/* bs - si */
124 	O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC,	/* dle - etb */
125 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* can - us */
126 	O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO,	/* sp - ' */
127 	E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO,	/* ( - / */
128 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* 0 - 7 */
129 	O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO,	/* 8 - ? */
130 	O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* @ - G */
131 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* H - O */
132 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* P - W */
133 	O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA,	/* X - _ */
134 	E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* ` - g */
135 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* h - o */
136 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* p - w */
137 	E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC,	/* x - del */
138 	/*
139 	 * Meta chars; should be settable per character set;
140 	 * for now, treat them all as normal characters.
141 	 */
142 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
143 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
144 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
145 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
146 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
147 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
148 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
149 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
150 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
151 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
152 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
153 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
154 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
155 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
156 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
157 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
158 };
159 #undef	BS
160 #undef	CC
161 #undef	CR
162 #undef	NA
163 #undef	NL
164 #undef	NO
165 #undef	TB
166 #undef	VT
167 
168 static struct ttylist_head tty_sigqueue = TAILQ_HEAD_INITIALIZER(tty_sigqueue);
169 static void *tty_sigsih;
170 
171 struct ttylist_head ttylist = TAILQ_HEAD_INITIALIZER(ttylist);
172 int tty_count;
173 kmutex_t tty_lock;
174 
175 POOL_INIT(tty_pool, sizeof(struct tty), 0, 0, 0, "ttypl",
176     &pool_allocator_nointr, IPL_NONE);
177 
178 uint64_t tk_cancc;
179 uint64_t tk_nin;
180 uint64_t tk_nout;
181 uint64_t tk_rawcc;
182 
183 SYSCTL_SETUP(sysctl_kern_tkstat_setup, "sysctl kern.tkstat subtree setup")
184 {
185 
186 	sysctl_createv(clog, 0, NULL, NULL,
187 		       CTLFLAG_PERMANENT,
188 		       CTLTYPE_NODE, "kern", NULL,
189 		       NULL, 0, NULL, 0,
190 		       CTL_KERN, CTL_EOL);
191 	sysctl_createv(clog, 0, NULL, NULL,
192 		       CTLFLAG_PERMANENT,
193 		       CTLTYPE_NODE, "tkstat",
194 		       SYSCTL_DESCR("Number of characters sent and and "
195 				    "received on ttys"),
196 		       NULL, 0, NULL, 0,
197 		       CTL_KERN, KERN_TKSTAT, CTL_EOL);
198 
199 	sysctl_createv(clog, 0, NULL, NULL,
200 		       CTLFLAG_PERMANENT,
201 		       CTLTYPE_QUAD, "nin",
202 		       SYSCTL_DESCR("Total number of tty input characters"),
203 		       NULL, 0, &tk_nin, 0,
204 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_NIN, CTL_EOL);
205 	sysctl_createv(clog, 0, NULL, NULL,
206 		       CTLFLAG_PERMANENT,
207 		       CTLTYPE_QUAD, "nout",
208 		       SYSCTL_DESCR("Total number of tty output characters"),
209 		       NULL, 0, &tk_nout, 0,
210 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_NOUT, CTL_EOL);
211 	sysctl_createv(clog, 0, NULL, NULL,
212 		       CTLFLAG_PERMANENT,
213 		       CTLTYPE_QUAD, "cancc",
214 		       SYSCTL_DESCR("Number of canonical tty input characters"),
215 		       NULL, 0, &tk_cancc, 0,
216 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_CANCC, CTL_EOL);
217 	sysctl_createv(clog, 0, NULL, NULL,
218 		       CTLFLAG_PERMANENT,
219 		       CTLTYPE_QUAD, "rawcc",
220 		       SYSCTL_DESCR("Number of raw tty input characters"),
221 		       NULL, 0, &tk_rawcc, 0,
222 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_RAWCC, CTL_EOL);
223 }
224 
225 int
226 ttyopen(struct tty *tp, int dialout, int nonblock)
227 {
228 	int	error;
229 
230 	error = 0;
231 
232 	mutex_spin_enter(&tty_lock);
233 
234 	if (dialout) {
235 		/*
236 		 * If the device is already open for non-dialout, fail.
237 		 * Otherwise, set TS_DIALOUT to block any pending non-dialout
238 		 * opens.
239 		 */
240 		if (ISSET(tp->t_state, TS_ISOPEN) &&
241 		    !ISSET(tp->t_state, TS_DIALOUT)) {
242 			error = EBUSY;
243 			goto out;
244 		}
245 		SET(tp->t_state, TS_DIALOUT);
246 	} else {
247 		if (!nonblock) {
248 			/*
249 			 * Wait for carrier.  Also wait for any dialout
250 			 * processes to close the tty first.
251 			 */
252 			while (ISSET(tp->t_state, TS_DIALOUT) ||
253 			       !CONNECTED(tp)) {
254 				tp->t_wopen++;
255 				error = ttysleep(tp, &tp->t_rawq.c_cv, true, 0);
256 				tp->t_wopen--;
257 				if (error)
258 					goto out;
259 			}
260 		} else {
261 			/*
262 			 * Don't allow a non-blocking non-dialout open if the
263 			 * device is already open for dialout.
264 			 */
265 			if (ISSET(tp->t_state, TS_DIALOUT)) {
266 				error = EBUSY;
267 				goto out;
268 			}
269 		}
270 	}
271 
272 out:
273 	mutex_spin_exit(&tty_lock);
274 	return (error);
275 }
276 
277 /*
278  * Initial open of tty, or (re)entry to standard tty line discipline.
279  */
280 int
281 ttylopen(dev_t device, struct tty *tp)
282 {
283 
284 	mutex_spin_enter(&tty_lock);
285 	tp->t_dev = device;
286 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
287 		SET(tp->t_state, TS_ISOPEN);
288 		memset(&tp->t_winsize, 0, sizeof(tp->t_winsize));
289 #ifdef COMPAT_OLDTTY
290 		tp->t_flags = 0;
291 #endif
292 	}
293 	mutex_spin_exit(&tty_lock);
294 	return (0);
295 }
296 
297 /*
298  * Handle close() on a tty line: flush and set to initial state,
299  * bumping generation number so that pending read/write calls
300  * can detect recycling of the tty.
301  */
302 int
303 ttyclose(struct tty *tp)
304 {
305 	extern struct tty *constty;	/* Temporary virtual console. */
306 	struct session *sess;
307 
308 	mutex_spin_enter(&tty_lock);
309 
310 	if (constty == tp)
311 		constty = NULL;
312 
313 	ttyflush(tp, FREAD | FWRITE);
314 
315 	tp->t_gen++;
316 	tp->t_pgrp = NULL;
317 	tp->t_state = 0;
318 
319 	mutex_spin_exit(&tty_lock);
320 
321 	mutex_enter(&proclist_lock);
322 	if ((sess = tp->t_session) != NULL) {
323 		SESSRELE(tp->t_session);
324 		tp->t_session = NULL;
325 	}
326 	mutex_exit(&proclist_lock);
327 
328 	return (0);
329 }
330 
331 #define	FLUSHQ(q) {							\
332 	if ((q)->c_cc)							\
333 		ndflush(q, (q)->c_cc);					\
334 }
335 
336 /*
337  * This macro is used in canonical mode input processing, where a read
338  * request shall not return unless a 'line delimiter' ('\n') or 'break'
339  * (EOF, EOL, EOL2) character (or a signal) has been received. As EOL2
340  * is an extension to the POSIX.1 defined set of special characters,
341  * recognize it only if IEXTEN is set in the set of local flags.
342  */
343 #define	TTBREAKC(c, lflg)						\
344 	((c) == '\n' || (((c) == cc[VEOF] || (c) == cc[VEOL] ||		\
345 	((c) == cc[VEOL2] && ISSET(lflg, IEXTEN))) && (c) != _POSIX_VDISABLE))
346 
347 
348 
349 /*
350  * ttyinput() helper.
351  * Call with the tty lock held.
352  */
353 static int
354 ttyinput_wlock(int c, struct tty *tp)
355 {
356 	int	iflag, lflag, i, error;
357 	u_char	*cc;
358 
359 	KASSERT(mutex_owned(&tty_lock));
360 
361 	/*
362 	 * If input is pending take it first.
363 	 */
364 	lflag = tp->t_lflag;
365 	if (ISSET(lflag, PENDIN))
366 		ttypend(tp);
367 	/*
368 	 * Gather stats.
369 	 */
370 	if (ISSET(lflag, ICANON)) {
371 		++tk_cancc;
372 		++tp->t_cancc;
373 	} else {
374 		++tk_rawcc;
375 		++tp->t_rawcc;
376 	}
377 	++tk_nin;
378 
379 	cc = tp->t_cc;
380 
381 	/*
382 	 * Handle exceptional conditions (break, parity, framing).
383 	 */
384 	iflag = tp->t_iflag;
385 	if ((error = (ISSET(c, TTY_ERRORMASK))) != 0) {
386 		CLR(c, TTY_ERRORMASK);
387 		if (ISSET(error, TTY_FE) && c == 0) {		/* Break. */
388 			if (ISSET(iflag, IGNBRK))
389 				return (0);
390 			else if (ISSET(iflag, BRKINT)) {
391 				ttyflush(tp, FREAD | FWRITE);
392 				ttysig(tp, TTYSIG_PG1, SIGINT);
393 				return (0);
394 			} else if (ISSET(iflag, PARMRK))
395 				goto parmrk;
396 		} else if ((ISSET(error, TTY_PE) && ISSET(iflag, INPCK)) ||
397 		    ISSET(error, TTY_FE)) {
398 			if (ISSET(iflag, IGNPAR))
399 				return (0);
400 			else if (ISSET(iflag, PARMRK)) {
401  parmrk:			(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
402 				(void)putc(0    | TTY_QUOTE, &tp->t_rawq);
403 				(void)putc(c    | TTY_QUOTE, &tp->t_rawq);
404 				return (0);
405 			} else
406 				c = 0;
407 		}
408 	} else if (c == 0377 &&
409 	    ISSET(iflag, ISTRIP|IGNPAR|INPCK|PARMRK) == (INPCK|PARMRK)) {
410 		/* "Escape" a valid character of '\377'. */
411 		(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
412 		(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
413 		goto endcase;
414 	}
415 
416 	/*
417 	 * In tandem mode, check high water mark.
418 	 */
419 	if (ISSET(iflag, IXOFF) || ISSET(tp->t_cflag, CHWFLOW))
420 		ttyblock(tp);
421 	if (!ISSET(tp->t_state, TS_TYPEN) && ISSET(iflag, ISTRIP))
422 		CLR(c, 0x80);
423 	if (!ISSET(lflag, EXTPROC)) {
424 		/*
425 		 * Check for literal nexting very first
426 		 */
427 		if (ISSET(tp->t_state, TS_LNCH)) {
428 			SET(c, TTY_QUOTE);
429 			CLR(tp->t_state, TS_LNCH);
430 		}
431 		/*
432 		 * Scan for special characters.  This code
433 		 * is really just a big case statement with
434 		 * non-constant cases.  The bottom of the
435 		 * case statement is labeled ``endcase'', so goto
436 		 * it after a case match, or similar.
437 		 */
438 
439 		/*
440 		 * Control chars which aren't controlled
441 		 * by ICANON, ISIG, or IXON.
442 		 */
443 		if (ISSET(lflag, IEXTEN)) {
444 			if (CCEQ(cc[VLNEXT], c)) {
445 				if (ISSET(lflag, ECHO)) {
446 					if (ISSET(lflag, ECHOE)) {
447 						(void)ttyoutput('^', tp);
448 						(void)ttyoutput('\b', tp);
449 					} else
450 						ttyecho(c, tp);
451 				}
452 				SET(tp->t_state, TS_LNCH);
453 				goto endcase;
454 			}
455 			if (CCEQ(cc[VDISCARD], c)) {
456 				if (ISSET(lflag, FLUSHO))
457 					CLR(tp->t_lflag, FLUSHO);
458 				else {
459 					ttyflush(tp, FWRITE);
460 					ttyecho(c, tp);
461 					if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
462 						ttyretype(tp);
463 					SET(tp->t_lflag, FLUSHO);
464 				}
465 				goto startoutput;
466 			}
467 		}
468 		/*
469 		 * Signals.
470 		 */
471 		if (ISSET(lflag, ISIG)) {
472 			if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
473 				if (!ISSET(lflag, NOFLSH))
474 					ttyflush(tp, FREAD | FWRITE);
475 				ttyecho(c, tp);
476 				ttysig(tp, TTYSIG_PG1, CCEQ(cc[VINTR], c) ?
477 				    SIGINT : SIGQUIT);
478 				goto endcase;
479 			}
480 			if (CCEQ(cc[VSUSP], c)) {
481 				if (!ISSET(lflag, NOFLSH))
482 					ttyflush(tp, FREAD);
483 				ttyecho(c, tp);
484 				ttysig(tp, TTYSIG_PG1, SIGTSTP);
485 				goto endcase;
486 			}
487 		}
488 		/*
489 		 * Handle start/stop characters.
490 		 */
491 		if (ISSET(iflag, IXON)) {
492 			if (CCEQ(cc[VSTOP], c)) {
493 				if (!ISSET(tp->t_state, TS_TTSTOP)) {
494 					SET(tp->t_state, TS_TTSTOP);
495 					cdev_stop(tp, 0);
496 					return (0);
497 				}
498 				if (!CCEQ(cc[VSTART], c))
499 					return (0);
500 				/*
501 				 * if VSTART == VSTOP then toggle
502 				 */
503 				goto endcase;
504 			}
505 			if (CCEQ(cc[VSTART], c))
506 				goto restartoutput;
507 		}
508 		/*
509 		 * IGNCR, ICRNL, & INLCR
510 		 */
511 		if (c == '\r') {
512 			if (ISSET(iflag, IGNCR))
513 				goto endcase;
514 			else if (ISSET(iflag, ICRNL))
515 				c = '\n';
516 		} else if (c == '\n' && ISSET(iflag, INLCR))
517 			c = '\r';
518 	}
519 	if (!ISSET(lflag, EXTPROC) && ISSET(lflag, ICANON)) {
520 		/*
521 		 * From here on down canonical mode character
522 		 * processing takes place.
523 		 */
524 		/*
525 		 * erase (^H / ^?)
526 		 */
527 		if (CCEQ(cc[VERASE], c)) {
528 			if (tp->t_rawq.c_cc)
529 				ttyrub(unputc(&tp->t_rawq), tp);
530 			goto endcase;
531 		}
532 		/*
533 		 * kill (^U)
534 		 */
535 		if (CCEQ(cc[VKILL], c)) {
536 			if (ISSET(lflag, ECHOKE) &&
537 			    tp->t_rawq.c_cc == tp->t_rocount &&
538 			    !ISSET(lflag, ECHOPRT))
539 				while (tp->t_rawq.c_cc)
540 					ttyrub(unputc(&tp->t_rawq), tp);
541 			else {
542 				ttyecho(c, tp);
543 				if (ISSET(lflag, ECHOK) ||
544 				    ISSET(lflag, ECHOKE))
545 					ttyecho('\n', tp);
546 				FLUSHQ(&tp->t_rawq);
547 				tp->t_rocount = 0;
548 			}
549 			CLR(tp->t_state, TS_LOCAL);
550 			goto endcase;
551 		}
552 		/*
553 		 * Extensions to the POSIX.1 GTI set of functions.
554 		 */
555 		if (ISSET(lflag, IEXTEN)) {
556 			/*
557 			 * word erase (^W)
558 			 */
559 			if (CCEQ(cc[VWERASE], c)) {
560 				int alt = ISSET(lflag, ALTWERASE);
561 				int ctype;
562 
563 				/*
564 				 * erase whitespace
565 				 */
566 				while ((c = unputc(&tp->t_rawq)) == ' ' ||
567 				    c == '\t')
568 					ttyrub(c, tp);
569 				if (c == -1)
570 					goto endcase;
571 				/*
572 				 * erase last char of word and remember the
573 				 * next chars type (for ALTWERASE)
574 				 */
575 				ttyrub(c, tp);
576 				c = unputc(&tp->t_rawq);
577 				if (c == -1)
578 					goto endcase;
579 				if (c == ' ' || c == '\t') {
580 					(void)putc(c, &tp->t_rawq);
581 					goto endcase;
582 				}
583 				ctype = ISALPHA(c);
584 				/*
585 				 * erase rest of word
586 				 */
587 				do {
588 					ttyrub(c, tp);
589 					c = unputc(&tp->t_rawq);
590 					if (c == -1)
591 						goto endcase;
592 				} while (c != ' ' && c != '\t' &&
593 				    (alt == 0 || ISALPHA(c) == ctype));
594 				(void)putc(c, &tp->t_rawq);
595 				goto endcase;
596 			}
597 			/*
598 			 * reprint line (^R)
599 			 */
600 			if (CCEQ(cc[VREPRINT], c)) {
601 				ttyretype(tp);
602 				goto endcase;
603 			}
604 			/*
605 			 * ^T - kernel info and generate SIGINFO
606 			 */
607 			if (CCEQ(cc[VSTATUS], c)) {
608 				if (!ISSET(lflag, NOKERNINFO))
609 					ttyinfo(tp, 1);
610 				if (ISSET(lflag, ISIG))
611 					ttysig(tp, TTYSIG_PG1, SIGINFO);
612 				goto endcase;
613 			}
614 		}
615 	}
616 	/*
617 	 * Check for input buffer overflow
618 	 */
619 	if (tp->t_rawq.c_cc + tp->t_canq.c_cc >= TTYHOG) {
620 		if (ISSET(iflag, IMAXBEL)) {
621 			if (tp->t_outq.c_cc < tp->t_hiwat)
622 				(void)ttyoutput(CTRL('g'), tp);
623 		} else
624 			ttyflush(tp, FREAD | FWRITE);
625 		goto endcase;
626 	}
627 	/*
628 	 * Put data char in q for user and
629 	 * wakeup on seeing a line delimiter.
630 	 */
631 	if (putc(c, &tp->t_rawq) >= 0) {
632 		if (!ISSET(lflag, ICANON)) {
633 			ttwakeup(tp);
634 			ttyecho(c, tp);
635 			goto endcase;
636 		}
637 		if (TTBREAKC(c, lflag)) {
638 			tp->t_rocount = 0;
639 			catq(&tp->t_rawq, &tp->t_canq);
640 			ttwakeup(tp);
641 		} else if (tp->t_rocount++ == 0)
642 			tp->t_rocol = tp->t_column;
643 		if (ISSET(tp->t_state, TS_ERASE)) {
644 			/*
645 			 * end of prterase \.../
646 			 */
647 			CLR(tp->t_state, TS_ERASE);
648 			(void)ttyoutput('/', tp);
649 		}
650 		i = tp->t_column;
651 		ttyecho(c, tp);
652 		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ECHO)) {
653 			/*
654 			 * Place the cursor over the '^' of the ^D.
655 			 */
656 			i = min(2, tp->t_column - i);
657 			while (i > 0) {
658 				(void)ttyoutput('\b', tp);
659 				i--;
660 			}
661 		}
662 	}
663  endcase:
664 	/*
665 	 * IXANY means allow any character to restart output.
666 	 */
667 	if (ISSET(tp->t_state, TS_TTSTOP) &&
668 	    !ISSET(iflag, IXANY) && cc[VSTART] != cc[VSTOP]) {
669 		return (0);
670 	}
671  restartoutput:
672 	CLR(tp->t_lflag, FLUSHO);
673 	CLR(tp->t_state, TS_TTSTOP);
674  startoutput:
675 	return (ttstart(tp));
676 }
677 
678 /*
679  * Process input of a single character received on a tty.
680  *
681  * XXX - this is a hack, all drivers must changed to acquire the
682  *	 lock before calling linesw->l_rint()
683  */
684 int
685 ttyinput(int c, struct tty *tp)
686 {
687 	int error;
688 
689 	/*
690 	 * Unless the receiver is enabled, drop incoming data.
691 	 */
692 	if (!ISSET(tp->t_cflag, CREAD))
693 		return (0);
694 
695 	mutex_spin_enter(&tty_lock);
696 	error = ttyinput_wlock(c, tp);
697 	mutex_spin_exit(&tty_lock);
698 
699 	return (error);
700 }
701 
702 /*
703  * Output a single character on a tty, doing output processing
704  * as needed (expanding tabs, newline processing, etc.).
705  * Returns < 0 if succeeds, otherwise returns char to resend.
706  * Must be recursive.
707  *
708  * Call with tty lock held.
709  */
710 int
711 ttyoutput(int c, struct tty *tp)
712 {
713 	long	oflag;
714 	int	col, notout;
715 
716 	KASSERT(mutex_owned(&tty_lock));
717 
718 	oflag = tp->t_oflag;
719 	if (!ISSET(oflag, OPOST)) {
720 		tk_nout++;
721 		tp->t_outcc++;
722 		if (!ISSET(tp->t_lflag, FLUSHO) && putc(c, &tp->t_outq))
723 			return (c);
724 		return (-1);
725 	}
726 	/*
727 	 * Do tab expansion if OXTABS is set.  Special case if we do external
728 	 * processing, we don't do the tab expansion because we'll probably
729 	 * get it wrong.  If tab expansion needs to be done, let it happen
730 	 * externally.
731 	 */
732 	CLR(c, ~TTY_CHARMASK);
733 	if (c == '\t' &&
734 	    ISSET(oflag, OXTABS) && !ISSET(tp->t_lflag, EXTPROC)) {
735 		c = 8 - (tp->t_column & 7);
736 		if (ISSET(tp->t_lflag, FLUSHO)) {
737 			notout = 0;
738 		} else {
739 			notout = b_to_q("        ", c, &tp->t_outq);
740 			c -= notout;
741 			tk_nout += c;
742 			tp->t_outcc += c;
743 		}
744 		tp->t_column += c;
745 		return (notout ? '\t' : -1);
746 	}
747 	if (c == CEOT && ISSET(oflag, ONOEOT))
748 		return (-1);
749 
750 	/*
751 	 * Newline translation: if ONLCR is set,
752 	 * translate newline into "\r\n".
753 	 */
754 	if (c == '\n' && ISSET(tp->t_oflag, ONLCR)) {
755 		tk_nout++;
756 		tp->t_outcc++;
757 		if (!ISSET(tp->t_lflag, FLUSHO) && putc('\r', &tp->t_outq))
758 			return (c);
759 	}
760 	/* If OCRNL is set, translate "\r" into "\n". */
761 	else if (c == '\r' && ISSET(tp->t_oflag, OCRNL))
762 		c = '\n';
763 	/* If ONOCR is set, don't transmit CRs when on column 0. */
764 	else if (c == '\r' && ISSET(tp->t_oflag, ONOCR) && tp->t_column == 0)
765 		return (-1);
766 
767 	tk_nout++;
768 	tp->t_outcc++;
769 	if (!ISSET(tp->t_lflag, FLUSHO) && putc(c, &tp->t_outq))
770 		return (c);
771 
772 	col = tp->t_column;
773 	switch (CCLASS(c)) {
774 	case BACKSPACE:
775 		if (col > 0)
776 			--col;
777 		break;
778 	case CONTROL:
779 		break;
780 	case NEWLINE:
781 		if (ISSET(tp->t_oflag, ONLCR | ONLRET))
782 			col = 0;
783 		break;
784 	case RETURN:
785 		col = 0;
786 		break;
787 	case ORDINARY:
788 		++col;
789 		break;
790 	case TAB:
791 		col = (col + 8) & ~7;
792 		break;
793 	}
794 	tp->t_column = col;
795 	return (-1);
796 }
797 
798 /*
799  * Ioctls for all tty devices.  Called after line-discipline specific ioctl
800  * has been called to do discipline-specific functions and/or reject any
801  * of these ioctl commands.
802  */
803 /* ARGSUSED */
804 int
805 ttioctl(struct tty *tp, u_long cmd, void *data, int flag, struct lwp *l)
806 {
807 	extern struct tty *constty;	/* Temporary virtual console. */
808 	struct proc *p = l ? l->l_proc : NULL;
809 	struct linesw	*lp;
810 	int		s, error;
811 	struct nameidata nd;
812 
813 	/* If the ioctl involves modification, hang if in the background. */
814 	switch (cmd) {
815 	case  TIOCFLUSH:
816 	case  TIOCDRAIN:
817 	case  TIOCSBRK:
818 	case  TIOCCBRK:
819 	case  TIOCSTART:
820 	case  TIOCSETA:
821 	case  TIOCSETD:
822 	case  TIOCSLINED:
823 	case  TIOCSETAF:
824 	case  TIOCSETAW:
825 #ifdef notdef
826 	case  TIOCSPGRP:
827 	case  FIOSETOWN:
828 #endif
829 	case  TIOCSTAT:
830 	case  TIOCSTI:
831 	case  TIOCSWINSZ:
832 #ifdef COMPAT_OLDTTY
833 	case  TIOCLBIC:
834 	case  TIOCLBIS:
835 	case  TIOCLSET:
836 	case  TIOCSETC:
837 	case OTIOCSETD:
838 	case  TIOCSETN:
839 	case  TIOCSETP:
840 	case  TIOCSLTC:
841 #endif
842 		/* XXXSMP */
843 		while (isbackground(curproc, tp) &&
844 		    p->p_pgrp->pg_jobc && (p->p_sflag & PS_PPWAIT) == 0 &&
845 		    !sigismasked(l, SIGTTOU)) {
846 			mutex_spin_enter(&tty_lock);
847 			ttysig(tp, TTYSIG_PG1, SIGTTOU);
848 			error = ttysleep(tp, &lbolt, true, 0);
849 			mutex_spin_exit(&tty_lock);
850 			if (error) {
851 				return (error);
852 			}
853 		}
854 		break;
855 	}
856 
857 	switch (cmd) {			/* Process the ioctl. */
858 	case FIOASYNC:			/* set/clear async i/o */
859 		mutex_spin_enter(&tty_lock);
860 		if (*(int *)data)
861 			SET(tp->t_state, TS_ASYNC);
862 		else
863 			CLR(tp->t_state, TS_ASYNC);
864 		mutex_spin_exit(&tty_lock);
865 		break;
866 	case FIONBIO:			/* set/clear non-blocking i/o */
867 		break;			/* XXX: delete. */
868 	case FIONREAD:			/* get # bytes to read */
869 		mutex_spin_enter(&tty_lock);
870 		*(int *)data = ttnread(tp);
871 		mutex_spin_exit(&tty_lock);
872 		break;
873 	case FIONWRITE:			/* get # bytes to written & unsent */
874 		mutex_spin_enter(&tty_lock);
875 		*(int *)data = tp->t_outq.c_cc;
876 		mutex_spin_exit(&tty_lock);
877 		break;
878 	case FIONSPACE:			/* get # bytes to written & unsent */
879 		mutex_spin_enter(&tty_lock);
880 		*(int *)data = tp->t_outq.c_cn - tp->t_outq.c_cc;
881 		mutex_spin_exit(&tty_lock);
882 		break;
883 	case TIOCEXCL:			/* set exclusive use of tty */
884 		mutex_spin_enter(&tty_lock);
885 		SET(tp->t_state, TS_XCLUDE);
886 		mutex_spin_exit(&tty_lock);
887 		break;
888 	case TIOCFLUSH: {		/* flush buffers */
889 		int flags = *(int *)data;
890 
891 		if (flags == 0)
892 			flags = FREAD | FWRITE;
893 		else
894 			flags &= FREAD | FWRITE;
895 		mutex_spin_enter(&tty_lock);
896 		ttyflush(tp, flags);
897 		mutex_spin_exit(&tty_lock);
898 		break;
899 	}
900 	case TIOCCONS:			/* become virtual console */
901 		if (*(int *)data) {
902 			if (constty && constty != tp &&
903 			    ISSET(constty->t_state, TS_CARR_ON | TS_ISOPEN) ==
904 			    (TS_CARR_ON | TS_ISOPEN))
905 				return EBUSY;
906 
907 			NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
908 			    "/dev/console");
909 			if ((error = namei(&nd)) != 0)
910 				return error;
911 			error = VOP_ACCESS(nd.ni_vp, VREAD, l->l_cred);
912 			vput(nd.ni_vp);
913 			if (error)
914 				return error;
915 
916 			constty = tp;
917 		} else if (tp == constty)
918 			constty = NULL;
919 		break;
920 	case TIOCDRAIN:			/* wait till output drained */
921 		if ((error = ttywait(tp)) != 0)
922 			return (error);
923 		break;
924 	case TIOCGETA: {		/* get termios struct */
925 		struct termios *t = (struct termios *)data;
926 
927 		memcpy(t, &tp->t_termios, sizeof(struct termios));
928 		break;
929 	}
930 	case TIOCGETD:			/* get line discipline (old) */
931 		*(int *)data = tp->t_linesw->l_no;
932 		break;
933 	case TIOCGLINED:		/* get line discipline (new) */
934 		(void)strncpy((char *)data, tp->t_linesw->l_name,
935 		    TTLINEDNAMELEN - 1);
936 		break;
937 	case TIOCGWINSZ:		/* get window size */
938 		*(struct winsize *)data = tp->t_winsize;
939 		break;
940 	case FIOGETOWN:
941 		if (tp->t_session != NULL && !isctty(p, tp))
942 			return (ENOTTY);
943 		*(int *)data = tp->t_pgrp ? -tp->t_pgrp->pg_id : 0;
944 		break;
945 	case TIOCGPGRP:			/* get pgrp of tty */
946 		if (!isctty(p, tp))
947 			return (ENOTTY);
948 		*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PGID;
949 		break;
950 	case TIOCGSID:			/* get sid of tty */
951 		if (!isctty(p, tp))
952 			return (ENOTTY);
953 		*(int *)data = tp->t_session->s_sid;
954 		break;
955 #ifdef TIOCHPCL
956 	case TIOCHPCL:			/* hang up on last close */
957 		mutex_spin_enter(&tty_lock);
958 		SET(tp->t_cflag, HUPCL);
959 		mutex_spin_exit(&tty_lock);
960 		break;
961 #endif
962 	case TIOCNXCL:			/* reset exclusive use of tty */
963 		mutex_spin_enter(&tty_lock);
964 		CLR(tp->t_state, TS_XCLUDE);
965 		mutex_spin_exit(&tty_lock);
966 		break;
967 	case TIOCOUTQ:			/* output queue size */
968 		*(int *)data = tp->t_outq.c_cc;
969 		break;
970 	case TIOCSETA:			/* set termios struct */
971 	case TIOCSETAW:			/* drain output, set */
972 	case TIOCSETAF: {		/* drn out, fls in, set */
973 		struct termios *t = (struct termios *)data;
974 
975 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
976 			if ((error = ttywait(tp)) != 0)
977 				return (error);
978 
979 			if (cmd == TIOCSETAF) {
980 				mutex_spin_enter(&tty_lock);
981 				ttyflush(tp, FREAD);
982 				mutex_spin_exit(&tty_lock);
983 			}
984 		}
985 
986 		s = spltty();
987 		/*
988 		 * XXXSMP - some drivers call back on us from t_param(), so
989 		 *	    don't take the tty spin lock here.
990 		 *	    require t_param() to unlock upon callback?
991 		 */
992 		/* wanted here: mutex_spin_enter(&tty_lock); */
993 		if (!ISSET(t->c_cflag, CIGNORE)) {
994 			/*
995 			 * Set device hardware.
996 			 */
997 			if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
998 				/* wanted here: mutex_spin_exit(&tty_lock); */
999 				splx(s);
1000 				return (error);
1001 			} else {
1002 				tp->t_cflag = t->c_cflag;
1003 				tp->t_ispeed = t->c_ispeed;
1004 				tp->t_ospeed = t->c_ospeed;
1005 				if (t->c_ospeed == 0)
1006 					ttysig(tp, TTYSIG_LEADER, SIGHUP);
1007 			}
1008 			ttsetwater(tp);
1009 		}
1010 
1011 		/* delayed lock acquiring */
1012 		mutex_spin_enter(&tty_lock);
1013 		if (cmd != TIOCSETAF) {
1014 			if (ISSET(t->c_lflag, ICANON) !=
1015 			    ISSET(tp->t_lflag, ICANON)) {
1016 				if (ISSET(t->c_lflag, ICANON)) {
1017 					SET(tp->t_lflag, PENDIN);
1018 					ttwakeup(tp);
1019 				} else {
1020 					struct clist tq;
1021 
1022 					catq(&tp->t_rawq, &tp->t_canq);
1023 					tq = tp->t_rawq;
1024 					tp->t_rawq = tp->t_canq;
1025 					tp->t_canq = tq;
1026 					CLR(tp->t_lflag, PENDIN);
1027 				}
1028 			}
1029 		}
1030 		tp->t_iflag = t->c_iflag;
1031 		tp->t_oflag = t->c_oflag;
1032 		/*
1033 		 * Make the EXTPROC bit read only.
1034 		 */
1035 		if (ISSET(tp->t_lflag, EXTPROC))
1036 			SET(t->c_lflag, EXTPROC);
1037 		else
1038 			CLR(t->c_lflag, EXTPROC);
1039 		tp->t_lflag = t->c_lflag | ISSET(tp->t_lflag, PENDIN);
1040 		memcpy(tp->t_cc, t->c_cc, sizeof(t->c_cc));
1041 		mutex_spin_exit(&tty_lock);
1042 		splx(s);
1043 		break;
1044 	}
1045 	case TIOCSETD:			/* set line discipline (old) */
1046 		lp = ttyldisc_lookup_bynum(*(int *)data);
1047 		goto setldisc;
1048 
1049 	case TIOCSLINED: {		/* set line discipline (new) */
1050 		char *name = (char *)data;
1051 		dev_t device;
1052 
1053 		/* Null terminate to prevent buffer overflow */
1054 		name[TTLINEDNAMELEN - 1] = '\0';
1055 		lp = ttyldisc_lookup(name);
1056  setldisc:
1057 		if (lp == NULL)
1058 			return (ENXIO);
1059 
1060 		if (lp != tp->t_linesw) {
1061 			device = tp->t_dev;
1062 			s = spltty();
1063 			(*tp->t_linesw->l_close)(tp, flag);
1064 			error = (*lp->l_open)(device, tp);
1065 			if (error) {
1066 				(void)(*tp->t_linesw->l_open)(device, tp);
1067 				splx(s);
1068 				ttyldisc_release(lp);
1069 				return (error);
1070 			}
1071 			ttyldisc_release(tp->t_linesw);
1072 			tp->t_linesw = lp;
1073 			splx(s);
1074 		} else {
1075 			/* Drop extra reference. */
1076 			ttyldisc_release(lp);
1077 		}
1078 		break;
1079 	}
1080 	case TIOCSTART:			/* start output, like ^Q */
1081 		mutex_spin_enter(&tty_lock);
1082 		if (ISSET(tp->t_state, TS_TTSTOP) ||
1083 		    ISSET(tp->t_lflag, FLUSHO)) {
1084 			CLR(tp->t_lflag, FLUSHO);
1085 			CLR(tp->t_state, TS_TTSTOP);
1086 			ttstart(tp);
1087 		}
1088 		mutex_spin_exit(&tty_lock);
1089 		break;
1090 	case TIOCSTI:			/* simulate terminal input */
1091 		if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
1092 		    NULL) != 0) {
1093 			if (!ISSET(flag, FREAD))
1094 				return (EPERM);
1095 			if (!isctty(p, tp))
1096 				return (EACCES);
1097 		}
1098 		(*tp->t_linesw->l_rint)(*(u_char *)data, tp);
1099 		break;
1100 	case TIOCSTOP:			/* stop output, like ^S */
1101 	{
1102 		mutex_spin_enter(&tty_lock);
1103 		if (!ISSET(tp->t_state, TS_TTSTOP)) {
1104 			SET(tp->t_state, TS_TTSTOP);
1105 			cdev_stop(tp, 0);
1106 		}
1107 		mutex_spin_exit(&tty_lock);
1108 		break;
1109 	}
1110 	case TIOCSCTTY:			/* become controlling tty */
1111 		mutex_enter(&proclist_lock);
1112 
1113 		/* Session ctty vnode pointer set in vnode layer. */
1114 		if (!SESS_LEADER(p) ||
1115 		    ((p->p_session->s_ttyvp || tp->t_session) &&
1116 		    (tp->t_session != p->p_session))) {
1117 			mutex_exit(&proclist_lock);
1118 			return (EPERM);
1119 		}
1120 
1121 		/*
1122 		 * `p_session' acquires a reference.
1123 		 * But note that if `t_session' is set at this point,
1124 		 * it must equal `p_session', in which case the session
1125 		 * already has the correct reference count.
1126 		 */
1127 		if (tp->t_session == NULL)
1128 			SESSHOLD(p->p_session);
1129 
1130 		tp->t_session = p->p_session;
1131 		tp->t_pgrp = p->p_pgrp;
1132 		p->p_session->s_ttyp = tp;
1133 		p->p_lflag |= PL_CONTROLT;
1134 		mutex_exit(&proclist_lock);
1135 		break;
1136 	case FIOSETOWN: {		/* set pgrp of tty */
1137 		pid_t pgid = *(int *)data;
1138 		struct pgrp *pgrp;
1139 
1140 		if (tp->t_session != NULL && !isctty(p, tp))
1141 			return (ENOTTY);
1142 
1143 		mutex_enter(&proclist_lock);
1144 
1145 		if (pgid < 0) {
1146 			pgrp = pg_find(-pgid, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
1147 			if (pgrp == NULL)
1148 				return (EINVAL);
1149 		} else {
1150 			struct proc *p1;
1151 			p1 = p_find(pgid, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
1152 			if (!p1)
1153 				return (ESRCH);
1154 			pgrp = p1->p_pgrp;
1155 		}
1156 
1157 		if (pgrp->pg_session != p->p_session) {
1158 			mutex_exit(&proclist_lock);
1159 			return (EPERM);
1160 		}
1161 		tp->t_pgrp = pgrp;
1162 		mutex_exit(&proclist_lock);
1163 		break;
1164 	}
1165 	case TIOCSPGRP: {		/* set pgrp of tty */
1166 		struct pgrp *pgrp;
1167 
1168 		if (!isctty(p, tp))
1169 			return (ENOTTY);
1170 		mutex_enter(&proclist_lock);
1171 		pgrp = pg_find(*(int *)data, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
1172 		if (pgrp == NULL)
1173 			return (EINVAL);
1174 		if (pgrp->pg_session != p->p_session) {
1175 			mutex_exit(&proclist_lock);
1176 			return (EPERM);
1177 		}
1178 		tp->t_pgrp = pgrp;
1179 		mutex_exit(&proclist_lock);
1180 		break;
1181 	}
1182 	case TIOCSTAT:			/* get load avg stats */
1183 		mutex_spin_enter(&tty_lock);
1184 		ttyinfo(tp, 0);
1185 		mutex_spin_exit(&tty_lock);
1186 		break;
1187 	case TIOCSWINSZ:		/* set window size */
1188 		mutex_spin_enter(&tty_lock);
1189 		if (memcmp((void *)&tp->t_winsize, data,
1190 		    sizeof(struct winsize))) {
1191 			tp->t_winsize = *(struct winsize *)data;
1192 			ttysig(tp, TTYSIG_PG1, SIGWINCH);
1193 		}
1194 		mutex_spin_exit(&tty_lock);
1195 		break;
1196 	default:
1197 #ifdef COMPAT_OLDTTY
1198 		return (ttcompat(tp, cmd, data, flag, l));
1199 #else
1200 		return (EPASSTHROUGH);
1201 #endif
1202 	}
1203 	return (0);
1204 }
1205 
1206 int
1207 ttpoll(struct tty *tp, int events, struct lwp *l)
1208 {
1209 	int	revents;
1210 
1211 	revents = 0;
1212 	mutex_spin_enter(&tty_lock);
1213 	if (events & (POLLIN | POLLRDNORM))
1214 		if (ttnread(tp) > 0)
1215 			revents |= events & (POLLIN | POLLRDNORM);
1216 
1217 	if (events & (POLLOUT | POLLWRNORM))
1218 		if (tp->t_outq.c_cc <= tp->t_lowat)
1219 			revents |= events & (POLLOUT | POLLWRNORM);
1220 
1221 	if (events & POLLHUP)
1222 		if (!CONNECTED(tp))
1223 			revents |= POLLHUP;
1224 
1225 	if (revents == 0) {
1226 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
1227 			selrecord(l, &tp->t_rsel);
1228 
1229 		if (events & (POLLOUT | POLLWRNORM))
1230 			selrecord(l, &tp->t_wsel);
1231 	}
1232 
1233 	mutex_spin_exit(&tty_lock);
1234 
1235 	return (revents);
1236 }
1237 
1238 static void
1239 filt_ttyrdetach(struct knote *kn)
1240 {
1241 	struct tty	*tp;
1242 
1243 	tp = kn->kn_hook;
1244 	mutex_spin_enter(&tty_lock);
1245 	SLIST_REMOVE(&tp->t_rsel.sel_klist, kn, knote, kn_selnext);
1246 	mutex_spin_exit(&tty_lock);
1247 }
1248 
1249 static int
1250 filt_ttyread(struct knote *kn, long hint)
1251 {
1252 	struct tty	*tp;
1253 
1254 	tp = kn->kn_hook;
1255 	if ((hint & NOTE_SUBMIT) == 0)
1256 		mutex_spin_enter(&tty_lock);
1257 	kn->kn_data = ttnread(tp);
1258 	if ((hint & NOTE_SUBMIT) == 0)
1259 		mutex_spin_exit(&tty_lock);
1260 	return (kn->kn_data > 0);
1261 }
1262 
1263 static void
1264 filt_ttywdetach(struct knote *kn)
1265 {
1266 	struct tty	*tp;
1267 
1268 	tp = kn->kn_hook;
1269 	mutex_spin_enter(&tty_lock);
1270 	SLIST_REMOVE(&tp->t_wsel.sel_klist, kn, knote, kn_selnext);
1271 	mutex_spin_exit(&tty_lock);
1272 }
1273 
1274 static int
1275 filt_ttywrite(struct knote *kn, long hint)
1276 {
1277 	struct tty	*tp;
1278 	int		canwrite;
1279 
1280 	tp = kn->kn_hook;
1281 	if ((hint & NOTE_SUBMIT) == 0)
1282 		mutex_spin_enter(&tty_lock);
1283 	kn->kn_data = tp->t_outq.c_cn - tp->t_outq.c_cc;
1284 	canwrite = (tp->t_outq.c_cc <= tp->t_lowat) && CONNECTED(tp);
1285 	if ((hint & NOTE_SUBMIT) == 0)
1286 		mutex_spin_exit(&tty_lock);
1287 	return (canwrite);
1288 }
1289 
1290 static const struct filterops ttyread_filtops =
1291 	{ 1, NULL, filt_ttyrdetach, filt_ttyread };
1292 static const struct filterops ttywrite_filtops =
1293 	{ 1, NULL, filt_ttywdetach, filt_ttywrite };
1294 
1295 int
1296 ttykqfilter(dev_t dev, struct knote *kn)
1297 {
1298 	struct tty	*tp;
1299 	struct klist	*klist;
1300 
1301 	if ((tp = cdev_tty(dev)) == NULL)
1302 		return (ENXIO);
1303 
1304 	switch (kn->kn_filter) {
1305 	case EVFILT_READ:
1306 		klist = &tp->t_rsel.sel_klist;
1307 		kn->kn_fop = &ttyread_filtops;
1308 		break;
1309 	case EVFILT_WRITE:
1310 		klist = &tp->t_wsel.sel_klist;
1311 		kn->kn_fop = &ttywrite_filtops;
1312 		break;
1313 	default:
1314 		return EINVAL;
1315 	}
1316 
1317 	kn->kn_hook = tp;
1318 
1319 	mutex_spin_enter(&tty_lock);
1320 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1321 	mutex_spin_exit(&tty_lock);
1322 
1323 	return (0);
1324 }
1325 
1326 /*
1327  * Find the number of chars ready to be read from this tty.
1328  * Call with the tty lock held.
1329  */
1330 static int
1331 ttnread(struct tty *tp)
1332 {
1333 	int	nread;
1334 
1335 	KASSERT(mutex_owned(&tty_lock));
1336 
1337 	if (ISSET(tp->t_lflag, PENDIN))
1338 		ttypend(tp);
1339 	nread = tp->t_canq.c_cc;
1340 	if (!ISSET(tp->t_lflag, ICANON)) {
1341 		nread += tp->t_rawq.c_cc;
1342 		if (nread < tp->t_cc[VMIN] && !tp->t_cc[VTIME])
1343 			nread = 0;
1344 	}
1345 	return (nread);
1346 }
1347 
1348 /*
1349  * Wait for output to drain.
1350  */
1351 int
1352 ttywait(struct tty *tp)
1353 {
1354 	int	error;
1355 
1356 	error = 0;
1357 
1358 	mutex_spin_enter(&tty_lock);
1359 	while ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1360 	    CONNECTED(tp) && tp->t_oproc) {
1361 		(*tp->t_oproc)(tp);
1362 		error = ttysleep(tp, &tp->t_outq.c_cv, true, 0);
1363 		if (error)
1364 			break;
1365 	}
1366 	mutex_spin_exit(&tty_lock);
1367 
1368 	return (error);
1369 }
1370 
1371 /*
1372  * Flush if successfully wait.
1373  */
1374 int
1375 ttywflush(struct tty *tp)
1376 {
1377 	int	error;
1378 
1379 	if ((error = ttywait(tp)) == 0) {
1380 		mutex_spin_enter(&tty_lock);
1381 		ttyflush(tp, FREAD);
1382 		mutex_spin_exit(&tty_lock);
1383 	}
1384 	return (error);
1385 }
1386 
1387 /*
1388  * Flush tty read and/or write queues, notifying anyone waiting.
1389  * Call with the tty lock held.
1390  */
1391 void
1392 ttyflush(struct tty *tp, int rw)
1393 {
1394 
1395 	KASSERT(mutex_owned(&tty_lock));
1396 
1397 	if (rw & FREAD) {
1398 		FLUSHQ(&tp->t_canq);
1399 		FLUSHQ(&tp->t_rawq);
1400 		tp->t_rocount = 0;
1401 		tp->t_rocol = 0;
1402 		CLR(tp->t_state, TS_LOCAL);
1403 		ttwakeup(tp);
1404 	}
1405 	if (rw & FWRITE) {
1406 		CLR(tp->t_state, TS_TTSTOP);
1407 		cdev_stop(tp, rw);
1408 		FLUSHQ(&tp->t_outq);
1409 		clwakeup(&tp->t_outq);
1410 		selnotify(&tp->t_wsel, NOTE_SUBMIT);
1411 	}
1412 }
1413 
1414 /*
1415  * Copy in the default termios characters.
1416  */
1417 void
1418 ttychars(struct tty *tp)
1419 {
1420 
1421 	memcpy(tp->t_cc, ttydefchars, sizeof(ttydefchars));
1422 }
1423 
1424 /*
1425  * Send stop character on input overflow.
1426  * Call with the tty lock held.
1427  */
1428 static void
1429 ttyblock(struct tty *tp)
1430 {
1431 	int	total;
1432 
1433 	KASSERT(mutex_owned(&tty_lock));
1434 
1435 	total = tp->t_rawq.c_cc + tp->t_canq.c_cc;
1436 	if (tp->t_rawq.c_cc > TTYHOG) {
1437 		ttyflush(tp, FREAD | FWRITE);
1438 		CLR(tp->t_state, TS_TBLOCK);
1439 	}
1440 	/*
1441 	 * Block further input iff: current input > threshold
1442 	 * AND input is available to user program.
1443 	 */
1444 	if (total >= TTYHOG / 2 &&
1445 	    !ISSET(tp->t_state, TS_TBLOCK) &&
1446 	    (!ISSET(tp->t_lflag, ICANON) || tp->t_canq.c_cc > 0)) {
1447 		if (ISSET(tp->t_iflag, IXOFF) &&
1448 		    tp->t_cc[VSTOP] != _POSIX_VDISABLE &&
1449 		    putc(tp->t_cc[VSTOP], &tp->t_outq) == 0) {
1450 			SET(tp->t_state, TS_TBLOCK);
1451 			ttstart(tp);
1452 		}
1453 		/* Try to block remote output via hardware flow control. */
1454 		if (ISSET(tp->t_cflag, CHWFLOW) && tp->t_hwiflow &&
1455 		    (*tp->t_hwiflow)(tp, 1) != 0)
1456 			SET(tp->t_state, TS_TBLOCK);
1457 	}
1458 }
1459 
1460 /*
1461  * Delayed line discipline output
1462  */
1463 void
1464 ttrstrt(void *tp_arg)
1465 {
1466 	struct tty	*tp;
1467 
1468 #ifdef DIAGNOSTIC
1469 	if (tp_arg == NULL)
1470 		panic("ttrstrt");
1471 #endif
1472 	tp = tp_arg;
1473 	mutex_spin_enter(&tty_lock);
1474 
1475 	CLR(tp->t_state, TS_TIMEOUT);
1476 	ttstart(tp); /* XXX - Shouldn't this be tp->l_start(tp)? */
1477 
1478 	mutex_spin_exit(&tty_lock);
1479 }
1480 
1481 /*
1482  * start a line discipline
1483  * Always call with tty lock held?
1484  */
1485 int
1486 ttstart(struct tty *tp)
1487 {
1488 
1489 	if (tp->t_oproc != NULL)	/* XXX: Kludge for pty. */
1490 		(*tp->t_oproc)(tp);
1491 	return (0);
1492 }
1493 
1494 /*
1495  * "close" a line discipline
1496  */
1497 int
1498 ttylclose(struct tty *tp, int flag)
1499 {
1500 
1501 	if (flag & FNONBLOCK) {
1502 		mutex_spin_enter(&tty_lock);
1503 		ttyflush(tp, FREAD | FWRITE);
1504 		mutex_spin_exit(&tty_lock);
1505 	} else
1506 		ttywflush(tp);
1507 	return (0);
1508 }
1509 
1510 /*
1511  * Handle modem control transition on a tty.
1512  * Flag indicates new state of carrier.
1513  * Returns 0 if the line should be turned off, otherwise 1.
1514  */
1515 int
1516 ttymodem(struct tty *tp, int flag)
1517 {
1518 
1519 	mutex_spin_enter(&tty_lock);
1520 	if (flag == 0) {
1521 		if (ISSET(tp->t_state, TS_CARR_ON)) {
1522 			/*
1523 			 * Lost carrier.
1524 			 */
1525 			CLR(tp->t_state, TS_CARR_ON);
1526 			if (ISSET(tp->t_state, TS_ISOPEN) && !CONNECTED(tp)) {
1527 				ttysig(tp, TTYSIG_LEADER, SIGHUP);
1528 				ttyflush(tp, FREAD | FWRITE);
1529 				mutex_spin_exit(&tty_lock);
1530 				return (0);
1531 			}
1532 		}
1533 	} else {
1534 		if (!ISSET(tp->t_state, TS_CARR_ON)) {
1535 			/*
1536 			 * Carrier now on.
1537 			 */
1538 			SET(tp->t_state, TS_CARR_ON);
1539 			ttwakeup(tp);
1540 		}
1541 	}
1542 	mutex_spin_exit(&tty_lock);
1543 
1544 	return (1);
1545 }
1546 
1547 /*
1548  * Default modem control routine (for other line disciplines).
1549  * Return argument flag, to turn off device on carrier drop.
1550  */
1551 int
1552 nullmodem(struct tty *tp, int flag)
1553 {
1554 
1555 	mutex_spin_enter(&tty_lock);
1556 	if (flag)
1557 		SET(tp->t_state, TS_CARR_ON);
1558 	else {
1559 		CLR(tp->t_state, TS_CARR_ON);
1560 		if (!CONNECTED(tp)) {
1561 			ttysig(tp, TTYSIG_LEADER, SIGHUP);
1562 			mutex_spin_exit(&tty_lock);
1563 			return (0);
1564 		}
1565 	}
1566 	mutex_spin_exit(&tty_lock);
1567 
1568 	return (1);
1569 }
1570 
1571 /*
1572  * Reinput pending characters after state switch.
1573  */
1574 void
1575 ttypend(struct tty *tp)
1576 {
1577 	struct clist	tq;
1578 	int		c;
1579 
1580 	KASSERT(mutex_owned(&tty_lock));
1581 
1582 	CLR(tp->t_lflag, PENDIN);
1583 	SET(tp->t_state, TS_TYPEN);
1584 	tq = tp->t_rawq;
1585 	tp->t_rawq.c_cc = 0;
1586 	tp->t_rawq.c_cf = tp->t_rawq.c_cl = 0;
1587 	while ((c = getc(&tq)) >= 0)
1588 		ttyinput_wlock(c, tp);
1589 	CLR(tp->t_state, TS_TYPEN);
1590 }
1591 
1592 /*
1593  * Process a read call on a tty device.
1594  */
1595 int
1596 ttread(struct tty *tp, struct uio *uio, int flag)
1597 {
1598 	struct clist	*qp;
1599 	u_char		*cc;
1600 	struct proc	*p;
1601 	int		c, first, error, has_stime, last_cc;
1602 	long		lflag, slp;
1603 	struct timeval	now, stime;
1604 
1605 	stime.tv_usec = 0;	/* XXX gcc */
1606 	stime.tv_sec = 0;	/* XXX gcc */
1607 
1608 	cc = tp->t_cc;
1609 	p = curproc;
1610 	error = 0;
1611 	has_stime = 0;
1612 	last_cc = 0;
1613 	slp = 0;
1614 
1615  loop:
1616 	mutex_spin_enter(&tty_lock);
1617 	lflag = tp->t_lflag;
1618 	/*
1619 	 * take pending input first
1620 	 */
1621 	if (ISSET(lflag, PENDIN))
1622 		ttypend(tp);
1623 
1624 	/*
1625 	 * Hang process if it's in the background. XXXSMP
1626 	 */
1627 	if (isbackground(p, tp)) {
1628 		if (sigismember(&p->p_sigctx.ps_sigignore, SIGTTIN) ||
1629 		    sigismember(&curlwp->l_sigmask, SIGTTIN) ||
1630 		    p->p_sflag & PS_PPWAIT || p->p_pgrp->pg_jobc == 0) {
1631 			mutex_spin_exit(&tty_lock);
1632 			return (EIO);
1633 		}
1634 		ttysig(tp, TTYSIG_PG1, SIGTTIN);
1635 		error = ttysleep(tp, &lbolt, true, 0);
1636 		mutex_spin_exit(&tty_lock);
1637 		if (error)
1638 			return (error);
1639 		goto loop;
1640 	}
1641 
1642 	if (!ISSET(lflag, ICANON)) {
1643 		int m = cc[VMIN];
1644 		long t = cc[VTIME];
1645 
1646 		qp = &tp->t_rawq;
1647 		/*
1648 		 * Check each of the four combinations.
1649 		 * (m > 0 && t == 0) is the normal read case.
1650 		 * It should be fairly efficient, so we check that and its
1651 		 * companion case (m == 0 && t == 0) first.
1652 		 * For the other two cases, we compute the target sleep time
1653 		 * into slp.
1654 		 */
1655 		if (t == 0) {
1656 			if (qp->c_cc < m)
1657 				goto sleep;
1658 			goto read;
1659 		}
1660 		t *= hz;		/* time in deca-ticks */
1661 /*
1662  * Time difference in deca-ticks, split division to avoid numeric overflow.
1663  * Ok for hz < ~200kHz
1664  */
1665 #define	diff(t1, t2) (((t1).tv_sec - (t2).tv_sec) * 10 * hz + \
1666 			 ((t1).tv_usec - (t2).tv_usec) / 100 * hz / 1000)
1667 		if (m > 0) {
1668 			if (qp->c_cc <= 0)
1669 				goto sleep;
1670 			if (qp->c_cc >= m)
1671 				goto read;
1672 			if (!has_stime) {
1673 				/* first character, start timer */
1674 				has_stime = 1;
1675 				getmicrotime(&stime);
1676 				slp = t;
1677 			} else if (qp->c_cc > last_cc) {
1678 				/* got a character, restart timer */
1679 				getmicrotime(&stime);
1680 				slp = t;
1681 			} else {
1682 				/* nothing, check expiration */
1683 				getmicrotime(&now);
1684 				slp = t - diff(now, stime);
1685 			}
1686 		} else {	/* m == 0 */
1687 			if (qp->c_cc > 0)
1688 				goto read;
1689 			if (!has_stime) {
1690 				has_stime = 1;
1691 				getmicrotime(&stime);
1692 				slp = t;
1693 			} else {
1694 				getmicrotime(&now);
1695 				slp = t - diff(now, stime);
1696 			}
1697 		}
1698 		last_cc = qp->c_cc;
1699 #undef diff
1700 		if (slp > 0) {
1701 			/*
1702 			 * Convert deca-ticks back to ticks.
1703 			 * Rounding down may make us wake up just short
1704 			 * of the target, so we round up.
1705 			 * Maybe we should do 'slp/10 + 1' because the
1706 			 * first tick maybe almost immediate.
1707 			 * However it is more useful for a program that sets
1708 			 * VTIME=10 to wakeup every second not every 1.01
1709 			 * seconds (if hz=100).
1710 			 */
1711 			slp = (slp + 9)/ 10;
1712 			goto sleep;
1713 		}
1714 	} else if ((qp = &tp->t_canq)->c_cc <= 0) {
1715 		int	carrier;
1716 
1717  sleep:
1718 		/*
1719 		 * If there is no input, sleep on rawq
1720 		 * awaiting hardware receipt and notification.
1721 		 * If we have data, we don't need to check for carrier.
1722 		 */
1723 		carrier = CONNECTED(tp);
1724 		if (!carrier && ISSET(tp->t_state, TS_ISOPEN)) {
1725 			mutex_spin_exit(&tty_lock);
1726 			return (0);	/* EOF */
1727 		}
1728 		if (flag & IO_NDELAY) {
1729 			mutex_spin_exit(&tty_lock);
1730 			return (EWOULDBLOCK);
1731 		}
1732 		error = ttysleep(tp, &tp->t_rawq.c_cv, true, slp);
1733 		mutex_spin_exit(&tty_lock);
1734 		/* VMIN == 0: any quantity read satisfies */
1735 		if (cc[VMIN] == 0 && error == EWOULDBLOCK)
1736 			return (0);
1737 		if (error && error != EWOULDBLOCK)
1738 			return (error);
1739 		goto loop;
1740 	}
1741  read:
1742 	mutex_spin_exit(&tty_lock);
1743 
1744 	/*
1745 	 * Input present, check for input mapping and processing.
1746 	 */
1747 	first = 1;
1748 	while ((c = getc(qp)) >= 0) {
1749 		/*
1750 		 * delayed suspend (^Y)
1751 		 */
1752 		if (CCEQ(cc[VDSUSP], c) &&
1753 		    ISSET(lflag, IEXTEN|ISIG) == (IEXTEN|ISIG)) {
1754 			mutex_spin_enter(&tty_lock);
1755 			ttysig(tp, TTYSIG_PG1, SIGTSTP);
1756 			if (first) {
1757 				error = ttysleep(tp, &lbolt, true, 0);
1758 				mutex_spin_exit(&tty_lock);
1759 				if (error)
1760 					break;
1761 				goto loop;
1762 			} else
1763 				mutex_spin_exit(&tty_lock);
1764 			break;
1765 		}
1766 		/*
1767 		 * Interpret EOF only in canonical mode.
1768 		 */
1769 		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ICANON))
1770 			break;
1771 		/*
1772 		 * Give user character.
1773 		 */
1774  		error = ureadc(c, uio);
1775 		if (error)
1776 			break;
1777  		if (uio->uio_resid == 0)
1778 			break;
1779 		/*
1780 		 * In canonical mode check for a "break character"
1781 		 * marking the end of a "line of input".
1782 		 */
1783 		if (ISSET(lflag, ICANON) && TTBREAKC(c, lflag))
1784 			break;
1785 		first = 0;
1786 	}
1787 	/*
1788 	 * Look to unblock output now that (presumably)
1789 	 * the input queue has gone down.
1790 	 */
1791 	mutex_spin_enter(&tty_lock);
1792 	if (ISSET(tp->t_state, TS_TBLOCK) && tp->t_rawq.c_cc < TTYHOG / 5) {
1793 		if (ISSET(tp->t_iflag, IXOFF) &&
1794 		    cc[VSTART] != _POSIX_VDISABLE &&
1795 		    putc(cc[VSTART], &tp->t_outq) == 0) {
1796 			CLR(tp->t_state, TS_TBLOCK);
1797 			ttstart(tp);
1798 		}
1799 		/* Try to unblock remote output via hardware flow control. */
1800 		if (ISSET(tp->t_cflag, CHWFLOW) && tp->t_hwiflow &&
1801 		    (*tp->t_hwiflow)(tp, 0) != 0)
1802 			CLR(tp->t_state, TS_TBLOCK);
1803 	}
1804 	mutex_spin_exit(&tty_lock);
1805 
1806 	return (error);
1807 }
1808 
1809 /*
1810  * Check the output queue on tp for space for a kernel message (from uprintf
1811  * or tprintf).  Allow some space over the normal hiwater mark so we don't
1812  * lose messages due to normal flow control, but don't let the tty run amok.
1813  * Sleeps here are not interruptible, but we return prematurely if new signals
1814  * arrive.
1815  * Call with tty lock held.
1816  */
1817 static int
1818 ttycheckoutq_wlock(struct tty *tp, int wait)
1819 {
1820 	int	hiwat, error;
1821 
1822 	KASSERT(mutex_owned(&tty_lock));
1823 
1824 	hiwat = tp->t_hiwat;
1825 	if (tp->t_outq.c_cc > hiwat + 200)
1826 		while (tp->t_outq.c_cc > hiwat) {
1827 			ttstart(tp);
1828 			if (wait == 0)
1829 				return (0);
1830 			error = ttysleep(tp, &tp->t_outq.c_cv, true, hz);
1831 			if (error == EINTR)
1832 				wait = 0;
1833 		}
1834 
1835 	return (1);
1836 }
1837 
1838 int
1839 ttycheckoutq(struct tty *tp, int wait)
1840 {
1841 	int	r;
1842 
1843 	mutex_spin_enter(&tty_lock);
1844 	r = ttycheckoutq_wlock(tp, wait);
1845 	mutex_spin_exit(&tty_lock);
1846 
1847 	return (r);
1848 }
1849 
1850 /*
1851  * Process a write call on a tty device.
1852  */
1853 int
1854 ttwrite(struct tty *tp, struct uio *uio, int flag)
1855 {
1856 	u_char		*cp;
1857 	struct proc	*p;
1858 	int		cc, ce, i, hiwat, error;
1859 	size_t		cnt;
1860 	u_char		obuf[OBUFSIZ];
1861 
1862 	cp = NULL;
1863 	hiwat = tp->t_hiwat;
1864 	cnt = uio->uio_resid;
1865 	error = 0;
1866 	cc = 0;
1867  loop:
1868 	mutex_spin_enter(&tty_lock);
1869 	if (!CONNECTED(tp)) {
1870 		if (ISSET(tp->t_state, TS_ISOPEN)) {
1871 			mutex_spin_exit(&tty_lock);
1872 			return (EIO);
1873 		} else if (flag & IO_NDELAY) {
1874 			mutex_spin_exit(&tty_lock);
1875 			error = EWOULDBLOCK;
1876 			goto out;
1877 		} else {
1878 			/* Sleep awaiting carrier. */
1879 			error = ttysleep(tp, &tp->t_rawq.c_cv, true, 0);
1880 			mutex_spin_exit(&tty_lock);
1881 			if (error)
1882 				goto out;
1883 			goto loop;
1884 		}
1885 	}
1886 	mutex_spin_exit(&tty_lock);
1887 	/*
1888 	 * Hang the process if it's in the background. XXXSMP
1889 	 */
1890 	p = curproc;
1891 	if (isbackground(p, tp) &&
1892 	    ISSET(tp->t_lflag, TOSTOP) && (p->p_sflag & PS_PPWAIT) == 0 &&
1893 	    !sigismember(&p->p_sigctx.ps_sigignore, SIGTTOU) &&
1894 	    !sigismember(&curlwp->l_sigmask, SIGTTOU)) {
1895 		if (p->p_pgrp->pg_jobc == 0) {
1896 			error = EIO;
1897 			goto out;
1898 		}
1899 		mutex_spin_enter(&tty_lock);
1900 		ttysig(tp, TTYSIG_PG1, SIGTTOU);
1901 		error = ttysleep(tp, &lbolt, true, 0);
1902 		mutex_spin_exit(&tty_lock);
1903 		if (error)
1904 			goto out;
1905 		goto loop;
1906 	}
1907 	/*
1908 	 * Process the user's data in at most OBUFSIZ chunks.  Perform any
1909 	 * output translation.  Keep track of high water mark, sleep on
1910 	 * overflow awaiting device aid in acquiring new space.
1911 	 */
1912 	while (uio->uio_resid > 0 || cc > 0) {
1913 		if (ISSET(tp->t_lflag, FLUSHO)) {
1914 			uio->uio_resid = 0;
1915 			return (0);
1916 		}
1917 		if (tp->t_outq.c_cc > hiwat)
1918 			goto ovhiwat;
1919 		/*
1920 		 * Grab a hunk of data from the user, unless we have some
1921 		 * leftover from last time.
1922 		 */
1923 		if (cc == 0) {
1924 			cc = min(uio->uio_resid, OBUFSIZ);
1925 			cp = obuf;
1926 			error = uiomove(cp, cc, uio);
1927 			if (error) {
1928 				cc = 0;
1929 				goto out;
1930 			}
1931 		}
1932 		/*
1933 		 * If nothing fancy need be done, grab those characters we
1934 		 * can handle without any of ttyoutput's processing and
1935 		 * just transfer them to the output q.  For those chars
1936 		 * which require special processing (as indicated by the
1937 		 * bits in char_type), call ttyoutput.  After processing
1938 		 * a hunk of data, look for FLUSHO so ^O's will take effect
1939 		 * immediately.
1940 		 */
1941 		mutex_spin_enter(&tty_lock);
1942 		while (cc > 0) {
1943 			if (!ISSET(tp->t_oflag, OPOST))
1944 				ce = cc;
1945 			else {
1946 				ce = cc - scanc((u_int)cc, cp, char_type,
1947 				    CCLASSMASK);
1948 				/*
1949 				 * If ce is zero, then we're processing
1950 				 * a special character through ttyoutput.
1951 				 */
1952 				if (ce == 0) {
1953 					tp->t_rocount = 0;
1954 					if (ttyoutput(*cp, tp) >= 0) {
1955 						/* out of space */
1956 						mutex_spin_exit(&tty_lock);
1957 						goto overfull;
1958 					}
1959 					cp++;
1960 					cc--;
1961 					if (ISSET(tp->t_lflag, FLUSHO) ||
1962 					    tp->t_outq.c_cc > hiwat) {
1963 						mutex_spin_exit(&tty_lock);
1964 						goto ovhiwat;
1965 					}
1966 					continue;
1967 				}
1968 			}
1969 			/*
1970 			 * A bunch of normal characters have been found.
1971 			 * Transfer them en masse to the output queue and
1972 			 * continue processing at the top of the loop.
1973 			 * If there are any further characters in this
1974 			 * <= OBUFSIZ chunk, the first should be a character
1975 			 * requiring special handling by ttyoutput.
1976 			 */
1977 			tp->t_rocount = 0;
1978 			i = b_to_q(cp, ce, &tp->t_outq);
1979 			ce -= i;
1980 			tp->t_column += ce;
1981 			cp += ce, cc -= ce, tk_nout += ce;
1982 			tp->t_outcc += ce;
1983 			if (i > 0) {
1984 				/* out of space */
1985 				mutex_spin_exit(&tty_lock);
1986 				goto overfull;
1987 			}
1988 			if (ISSET(tp->t_lflag, FLUSHO) ||
1989 			    tp->t_outq.c_cc > hiwat)
1990 				break;
1991 		}
1992 		ttstart(tp);
1993 		mutex_spin_exit(&tty_lock);
1994 	}
1995 
1996  out:
1997 	/*
1998 	 * If cc is nonzero, we leave the uio structure inconsistent, as the
1999 	 * offset and iov pointers have moved forward, but it doesn't matter
2000 	 * (the call will either return short or restart with a new uio).
2001 	 */
2002 	uio->uio_resid += cc;
2003 	return (error);
2004 
2005  overfull:
2006 	/*
2007 	 * Since we are using ring buffers, if we can't insert any more into
2008 	 * the output queue, we can assume the ring is full and that someone
2009 	 * forgot to set the high water mark correctly.  We set it and then
2010 	 * proceed as normal.
2011 	 */
2012 	hiwat = tp->t_outq.c_cc - 1;
2013 
2014  ovhiwat:
2015 	mutex_spin_enter(&tty_lock);
2016 	ttstart(tp);
2017 	/*
2018 	 * This can only occur if FLUSHO is set in t_lflag,
2019 	 * or if ttstart/oproc is synchronous (or very fast).
2020 	 */
2021 	if (tp->t_outq.c_cc <= hiwat) {
2022 		mutex_spin_exit(&tty_lock);
2023 		goto loop;
2024 	}
2025 	if (flag & IO_NDELAY) {
2026 		mutex_spin_exit(&tty_lock);
2027 		error = EWOULDBLOCK;
2028 		goto out;
2029 	}
2030 	error = ttysleep(tp, &tp->t_outq.c_cv, true, 0);
2031 	mutex_spin_exit(&tty_lock);
2032 	if (error)
2033 		goto out;
2034 	goto loop;
2035 }
2036 
2037 /*
2038  * Try to pull more output from the producer.  Return non-zero if
2039  * there is output ready to be sent.
2040  */
2041 bool
2042 ttypull(struct tty *tp)
2043 {
2044 
2045 	/* XXXSMP not yet KASSERT(mutex_owned(&tty_lock)); */
2046 
2047 	if (tp->t_outq.c_cc <= tp->t_lowat) {
2048 		clwakeup(&tp->t_outq);
2049 		selnotify(&tp->t_wsel, NOTE_SUBMIT);
2050 	}
2051 	return tp->t_outq.c_cc != 0;
2052 }
2053 
2054 /*
2055  * Rubout one character from the rawq of tp
2056  * as cleanly as possible.
2057  * Called with tty lock held.
2058  */
2059 void
2060 ttyrub(int c, struct tty *tp)
2061 {
2062 	u_char	*cp;
2063 	int	savecol, tabc;
2064 
2065 	KASSERT(mutex_owned(&tty_lock));
2066 
2067 	if (!ISSET(tp->t_lflag, ECHO) || ISSET(tp->t_lflag, EXTPROC))
2068 		return;
2069 	CLR(tp->t_lflag, FLUSHO);
2070 	if (ISSET(tp->t_lflag, ECHOE)) {
2071 		if (tp->t_rocount == 0) {
2072 			/*
2073 			 * Screwed by ttwrite; retype
2074 			 */
2075 			ttyretype(tp);
2076 			return;
2077 		}
2078 		if (c == ('\t' | TTY_QUOTE) || c == ('\n' | TTY_QUOTE))
2079 			ttyrubo(tp, 2);
2080 		else {
2081 			CLR(c, ~TTY_CHARMASK);
2082 			switch (CCLASS(c)) {
2083 			case ORDINARY:
2084 				ttyrubo(tp, 1);
2085 				break;
2086 			case BACKSPACE:
2087 			case CONTROL:
2088 			case NEWLINE:
2089 			case RETURN:
2090 			case VTAB:
2091 				if (ISSET(tp->t_lflag, ECHOCTL))
2092 					ttyrubo(tp, 2);
2093 				break;
2094 			case TAB:
2095 				if (tp->t_rocount < tp->t_rawq.c_cc) {
2096 					ttyretype(tp);
2097 					return;
2098 				}
2099 				savecol = tp->t_column;
2100 				SET(tp->t_state, TS_CNTTB);
2101 				SET(tp->t_lflag, FLUSHO);
2102 				tp->t_column = tp->t_rocol;
2103 				for (cp = firstc(&tp->t_rawq, &tabc); cp;
2104 				    cp = nextc(&tp->t_rawq, cp, &tabc))
2105 					ttyecho(tabc, tp);
2106 				CLR(tp->t_lflag, FLUSHO);
2107 				CLR(tp->t_state, TS_CNTTB);
2108 
2109 				/* savecol will now be length of the tab. */
2110 				savecol -= tp->t_column;
2111 				tp->t_column += savecol;
2112 				if (savecol > 8)
2113 					savecol = 8;	/* overflow screw */
2114 				while (--savecol >= 0)
2115 					(void)ttyoutput('\b', tp);
2116 				break;
2117 			default:			/* XXX */
2118 				(void)printf("ttyrub: would panic c = %d, "
2119 				    "val = %d\n", c, CCLASS(c));
2120 			}
2121 		}
2122 	} else if (ISSET(tp->t_lflag, ECHOPRT)) {
2123 		if (!ISSET(tp->t_state, TS_ERASE)) {
2124 			SET(tp->t_state, TS_ERASE);
2125 			(void)ttyoutput('\\', tp);
2126 		}
2127 		ttyecho(c, tp);
2128 	} else
2129 		ttyecho(tp->t_cc[VERASE], tp);
2130 	--tp->t_rocount;
2131 }
2132 
2133 /*
2134  * Back over cnt characters, erasing them.
2135  * Called with tty lock held.
2136  */
2137 static void
2138 ttyrubo(struct tty *tp, int cnt)
2139 {
2140 
2141 	KASSERT(mutex_owned(&tty_lock));
2142 
2143 	while (cnt-- > 0) {
2144 		(void)ttyoutput('\b', tp);
2145 		(void)ttyoutput(' ', tp);
2146 		(void)ttyoutput('\b', tp);
2147 	}
2148 }
2149 
2150 /*
2151  * ttyretype --
2152  *	Reprint the rawq line.  Note, it is assumed that c_cc has already
2153  *	been checked.
2154  *
2155  * Called with tty lock held.
2156  */
2157 void
2158 ttyretype(struct tty *tp)
2159 {
2160 	u_char	*cp;
2161 	int	c;
2162 
2163 	KASSERT(mutex_owned(&tty_lock));
2164 
2165 	/* Echo the reprint character. */
2166 	if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
2167 		ttyecho(tp->t_cc[VREPRINT], tp);
2168 
2169 	(void)ttyoutput('\n', tp);
2170 
2171 	for (cp = firstc(&tp->t_canq, &c); cp; cp = nextc(&tp->t_canq, cp, &c))
2172 		ttyecho(c, tp);
2173 	for (cp = firstc(&tp->t_rawq, &c); cp; cp = nextc(&tp->t_rawq, cp, &c))
2174 		ttyecho(c, tp);
2175 	CLR(tp->t_state, TS_ERASE);
2176 
2177 	tp->t_rocount = tp->t_rawq.c_cc;
2178 	tp->t_rocol = 0;
2179 }
2180 
2181 /*
2182  * Echo a typed character to the terminal.
2183  * Called with tty lock held.
2184  */
2185 static void
2186 ttyecho(int c, struct tty *tp)
2187 {
2188 
2189 	KASSERT(mutex_owned(&tty_lock));
2190 
2191 	if (!ISSET(tp->t_state, TS_CNTTB))
2192 		CLR(tp->t_lflag, FLUSHO);
2193 	if ((!ISSET(tp->t_lflag, ECHO) &&
2194 	    (!ISSET(tp->t_lflag, ECHONL) || c != '\n')) ||
2195 	    ISSET(tp->t_lflag, EXTPROC))
2196 		return;
2197 	if (((ISSET(tp->t_lflag, ECHOCTL) &&
2198 	    (ISSET(c, TTY_CHARMASK) <= 037 && c != '\t' && c != '\n')) ||
2199 	    ISSET(c, TTY_CHARMASK) == 0177)) {
2200 		(void)ttyoutput('^', tp);
2201 		CLR(c, ~TTY_CHARMASK);
2202 		if (c == 0177)
2203 			c = '?';
2204 		else
2205 			c += 'A' - 1;
2206 	}
2207 	(void)ttyoutput(c, tp);
2208 }
2209 
2210 /*
2211  * Wake up any readers on a tty.
2212  * Called with tty lock held.
2213  */
2214 void
2215 ttwakeup(struct tty *tp)
2216 {
2217 
2218 	KASSERT(mutex_owned(&tty_lock));
2219 
2220 	selnotify(&tp->t_rsel, NOTE_SUBMIT);
2221 	if (ISSET(tp->t_state, TS_ASYNC))
2222 		ttysig(tp, TTYSIG_PG2, SIGIO);
2223 #if 0
2224 	/* XXX tp->t_rawq.c_cv.cv_waiters dropping to zero early!? */
2225 	clwakeup(&tp->t_rawq);
2226 #else
2227 	cv_wakeup(&tp->t_rawq.c_cv);
2228 #endif
2229 }
2230 
2231 /*
2232  * Look up a code for a specified speed in a conversion table;
2233  * used by drivers to map software speed values to hardware parameters.
2234  */
2235 int
2236 ttspeedtab(int speed, const struct speedtab *table)
2237 {
2238 
2239 	for (; table->sp_speed != -1; table++)
2240 		if (table->sp_speed == speed)
2241 			return (table->sp_code);
2242 	return (-1);
2243 }
2244 
2245 /*
2246  * Set tty hi and low water marks.
2247  *
2248  * Try to arrange the dynamics so there's about one second
2249  * from hi to low water.
2250  */
2251 void
2252 ttsetwater(struct tty *tp)
2253 {
2254 	int	cps, x;
2255 
2256 	/* XXX not yet KASSERT(mutex_owned(&tty_lock)); */
2257 
2258 #define	CLAMP(x, h, l)	((x) > h ? h : ((x) < l) ? l : (x))
2259 
2260 	cps = tp->t_ospeed / 10;
2261 	tp->t_lowat = x = CLAMP(cps / 2, TTMAXLOWAT, TTMINLOWAT);
2262 	x += cps;
2263 	x = CLAMP(x, TTMAXHIWAT, TTMINHIWAT);
2264 	tp->t_hiwat = roundup(x, CBSIZE);
2265 #undef	CLAMP
2266 }
2267 
2268 /*
2269  * Report on state of foreground process group.
2270  * Call with tty lock held.
2271  * XXXSMP locking.
2272  */
2273 void
2274 ttyinfo(struct tty *tp, int fromsig)
2275 {
2276 	struct lwp	*l;
2277 	struct proc	*p, *pick = NULL;
2278 	struct timeval	utime, stime;
2279 	int		tmp;
2280 	fixpt_t		pctcpu = 0;
2281 	const char	*msg;
2282 
2283 	if (ttycheckoutq_wlock(tp, 0) == 0)
2284 		return;
2285 
2286 	if (tp->t_session == NULL)
2287 		msg = "not a controlling terminal\n";
2288 	else if (tp->t_pgrp == NULL)
2289 		msg = "no foreground process group\n";
2290 	else if ((p = LIST_FIRST(&tp->t_pgrp->pg_members)) == NULL)
2291 		msg = "empty foreground process group\n";
2292 	else {
2293 		/* Pick interesting process. */
2294 		for (; p != NULL; p = LIST_NEXT(p, p_pglist))
2295 			if (proc_compare(pick, p))
2296 				pick = p;
2297 		if (fromsig &&
2298 		    (SIGACTION_PS(pick->p_sigacts, SIGINFO).sa_flags &
2299 		    SA_NOKERNINFO))
2300 			return;
2301 		msg = NULL;
2302 	}
2303 
2304 	/* Print load average. */
2305 	tmp = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
2306 	ttyprintf_nolock(tp, "load: %d.%02d ", tmp / 100, tmp % 100);
2307 
2308 	if (pick == NULL) {
2309 		ttyprintf_nolock(tp, msg);
2310 		tp->t_rocount = 0; /* so pending input will be retyped if BS */
2311 		return;
2312 	}
2313 
2314 	ttyprintf_nolock(tp, " cmd: %s %d [", pick->p_comm, pick->p_pid);
2315 	LIST_FOREACH(l, &pick->p_lwps, l_sibling) {
2316 	    ttyprintf_nolock(tp, "%s%s",
2317 	    l->l_stat == LSONPROC ? "running" :
2318 	    l->l_stat == LSRUN ? "runnable" :
2319 	    l->l_wmesg ? l->l_wmesg : "iowait",
2320 		(LIST_NEXT(l, l_sibling) != NULL) ? " " : "] ");
2321 	    pctcpu += l->l_pctcpu;
2322 	}
2323 	pctcpu += pick->p_pctcpu;
2324 
2325 	mutex_enter(&pick->p_smutex);
2326 	calcru(pick, &utime, &stime, NULL, NULL);
2327 	mutex_exit(&pick->p_smutex);
2328 
2329 	/* Round up and print user time. */
2330 	utime.tv_usec += 5000;
2331 	if (utime.tv_usec >= 1000000) {
2332 		utime.tv_sec += 1;
2333 		utime.tv_usec -= 1000000;
2334 	}
2335 	ttyprintf_nolock(tp, "%ld.%02ldu ", (long int)utime.tv_sec,
2336 	    (long int)utime.tv_usec / 10000);
2337 
2338 	/* Round up and print system time. */
2339 	stime.tv_usec += 5000;
2340 	if (stime.tv_usec >= 1000000) {
2341 		stime.tv_sec += 1;
2342 		stime.tv_usec -= 1000000;
2343 	}
2344 	ttyprintf_nolock(tp, "%ld.%02lds ", (long int)stime.tv_sec,
2345 	    (long int)stime.tv_usec / 10000);
2346 
2347 #define	pgtok(a)	(((u_long) ((a) * PAGE_SIZE) / 1024))
2348 	/* Print percentage CPU. */
2349 	tmp = (pctcpu * 10000 + FSCALE / 2) >> FSHIFT;
2350 	ttyprintf_nolock(tp, "%d%% ", tmp / 100);
2351 
2352 	/* Print resident set size. */
2353 	if (pick->p_stat == SIDL || P_ZOMBIE(pick))
2354 		tmp = 0;
2355 	else {
2356 		struct vmspace *vm = pick->p_vmspace;
2357 		tmp = pgtok(vm_resident_count(vm));
2358 	}
2359 	ttyprintf_nolock(tp, "%dk\n", tmp);
2360 	tp->t_rocount = 0;	/* so pending input will be retyped if BS */
2361 }
2362 
2363 /*
2364  * Returns 1 if p2 is "better" than p1
2365  *
2366  * The algorithm for picking the "interesting" process is thus:
2367  *
2368  *	1) Only foreground processes are eligible - implied.
2369  *	2) Runnable processes are favored over anything else.  The runner
2370  *	   with the highest CPU utilization is picked (l_pctcpu).  Ties are
2371  *	   broken by picking the highest pid.
2372  *	3) The sleeper with the shortest sleep time is next.  With ties,
2373  *	   we pick out just "short-term" sleepers (P_SINTR == 0).
2374  *	4) Further ties are broken by picking the highest pid.
2375  *
2376  * XXXSMP
2377  */
2378 #define	ISRUN(p)	((p)->p_nrlwps > 0)
2379 #define	TESTAB(a, b)	((a)<<1 | (b))
2380 #define	ONLYA	2
2381 #define	ONLYB	1
2382 #define	BOTH	3
2383 
2384 static int
2385 proc_compare(struct proc *p1, struct proc *p2)
2386 {
2387 	lwp_t *l1, *l2;
2388 
2389 	if (p1 == NULL)
2390 		return (1);
2391 	/*
2392 	 * see if at least one of them is runnable
2393 	 */
2394 	switch (TESTAB(ISRUN(p1), ISRUN(p2))) {
2395 	case ONLYA:
2396 		return (0);
2397 	case ONLYB:
2398 		return (1);
2399 	case BOTH:
2400 		/*
2401 		 * tie - favor one with highest recent CPU utilization
2402 		 */
2403 		l1 = LIST_FIRST(&p1->p_lwps);
2404 		l2 = LIST_FIRST(&p2->p_lwps);
2405 		if (l2->l_pctcpu > l1->l_pctcpu)
2406 			return (1);
2407 		return (p2->p_pid > p1->p_pid);	/* tie - return highest pid */
2408 	}
2409 	/*
2410  	 * weed out zombies
2411 	 */
2412 	switch (TESTAB(P_ZOMBIE(p1), P_ZOMBIE(p2))) {
2413 	case ONLYA:
2414 		return (1);
2415 	case ONLYB:
2416 		return (0);
2417 	case BOTH:
2418 		return (p2->p_pid > p1->p_pid);	/* tie - return highest pid */
2419 	}
2420 #if 0 /* XXX NJWLWP */
2421 	/*
2422 	 * pick the one with the smallest sleep time
2423 	 */
2424 	if (p2->p_slptime > p1->p_slptime)
2425 		return (0);
2426 	if (p1->p_slptime > p2->p_slptime)
2427 		return (1);
2428 	/*
2429 	 * favor one sleeping in a non-interruptible sleep
2430 	 */
2431 	if (p1->p_flag & P_SINTR && (p2->p_flag & P_SINTR) == 0)
2432 		return (1);
2433 	if (p2->p_flag & P_SINTR && (p1->p_flag & P_SINTR) == 0)
2434 		return (0);
2435 #endif
2436 	return (p2->p_pid > p1->p_pid);		/* tie - return highest pid */
2437 }
2438 
2439 /*
2440  * Output char to tty; console putchar style.
2441  * Can be called with tty lock held through kprintf() machinery..
2442  */
2443 int
2444 tputchar(int c, int flags, struct tty *tp)
2445 {
2446 	int r = 0;
2447 
2448 	if ((flags & NOLOCK) == 0)
2449 		mutex_spin_enter(&tty_lock);
2450 	if (!CONNECTED(tp)) {
2451 		r = -1;
2452 		goto out;
2453 	}
2454 	if (c == '\n')
2455 		(void)ttyoutput('\r', tp);
2456 	(void)ttyoutput(c, tp);
2457 	ttstart(tp);
2458 out:
2459 	if ((flags & NOLOCK) == 0)
2460 		mutex_spin_exit(&tty_lock);
2461 	return (r);
2462 }
2463 
2464 /*
2465  * Sleep on chan, returning ERESTART if tty changed while we napped and
2466  * returning any errors (e.g. EINTR/ETIMEDOUT) reported by tsleep.  If
2467  * the tty is revoked, restarting a pending call will redo validation done
2468  * at the start of the call.
2469  *
2470  * Must be called with the tty lock held.
2471  */
2472 int
2473 ttysleep(struct tty *tp, kcondvar_t *cv, bool catch, int timo)
2474 {
2475 	int	error;
2476 	short	gen;
2477 
2478 	KASSERT(mutex_owned(&tty_lock));
2479 
2480 	gen = tp->t_gen;
2481 	if (catch)
2482 		error = cv_timedwait_sig(cv, &tty_lock, timo);
2483 	else
2484 		error = cv_timedwait(cv, &tty_lock, timo);
2485 	if (error != 0)
2486 		return (error);
2487 	return (tp->t_gen == gen ? 0 : ERESTART);
2488 }
2489 
2490 /*
2491  * Attach a tty to the tty list.
2492  *
2493  * This should be called ONLY once per real tty (including pty's).
2494  * eg, on the sparc, the keyboard and mouse have struct tty's that are
2495  * distinctly NOT usable as tty's, and thus should not be attached to
2496  * the ttylist.  This is why this call is not done from ttymalloc().
2497  *
2498  * Device drivers should attach tty's at a similar time that they are
2499  * ttymalloc()'ed, or, for the case of statically allocated struct tty's
2500  * either in the attach or (first) open routine.
2501  */
2502 void
2503 tty_attach(struct tty *tp)
2504 {
2505 
2506 	mutex_spin_enter(&tty_lock);
2507 	TAILQ_INSERT_TAIL(&ttylist, tp, tty_link);
2508 	++tty_count;
2509 	mutex_spin_exit(&tty_lock);
2510 }
2511 
2512 /*
2513  * Remove a tty from the tty list.
2514  */
2515 void
2516 tty_detach(struct tty *tp)
2517 {
2518 
2519 	mutex_spin_enter(&tty_lock);
2520 	--tty_count;
2521 #ifdef DIAGNOSTIC
2522 	if (tty_count < 0)
2523 		panic("tty_detach: tty_count < 0");
2524 #endif
2525 	TAILQ_REMOVE(&ttylist, tp, tty_link);
2526 	mutex_spin_exit(&tty_lock);
2527 }
2528 
2529 /*
2530  * Allocate a tty structure and its associated buffers.
2531  */
2532 struct tty *
2533 ttymalloc(void)
2534 {
2535 	struct tty	*tp;
2536 	int i;
2537 
2538 	tp = pool_get(&tty_pool, PR_WAITOK);
2539 	memset(tp, 0, sizeof(*tp));
2540 	callout_init(&tp->t_rstrt_ch, 0);
2541 	callout_setfunc(&tp->t_rstrt_ch, ttrstrt, tp);
2542 	/* XXX: default to 1024 chars for now */
2543 	clalloc(&tp->t_rawq, 1024, 1);
2544 	clalloc(&tp->t_canq, 1024, 1);
2545 	/* output queue doesn't need quoting */
2546 	clalloc(&tp->t_outq, 1024, 0);
2547 	/* Set default line discipline. */
2548 	tp->t_linesw = ttyldisc_default();
2549 	selinit(&tp->t_rsel);
2550 	selinit(&tp->t_wsel);
2551 	for (i = 0; i < TTYSIG_COUNT; i++)
2552 		sigemptyset(&tp->t_sigs[i]);
2553 	return (tp);
2554 }
2555 
2556 /*
2557  * Free a tty structure and its buffers.
2558  *
2559  * Be sure to call tty_detach() for any tty that has been
2560  * tty_attach()ed.
2561  */
2562 void
2563 ttyfree(struct tty *tp)
2564 {
2565 	int i;
2566 
2567 	mutex_enter(&tty_lock);
2568 	for (i = 0; i < TTYSIG_COUNT; i++)
2569 		sigemptyset(&tp->t_sigs[i]);
2570 	if (tp->t_sigcount != 0)
2571 		TAILQ_REMOVE(&tty_sigqueue, tp, t_sigqueue);
2572 	mutex_exit(&tty_lock);
2573 
2574 	callout_stop(&tp->t_rstrt_ch);
2575 	ttyldisc_release(tp->t_linesw);
2576 	clfree(&tp->t_rawq);
2577 	clfree(&tp->t_canq);
2578 	clfree(&tp->t_outq);
2579 	callout_destroy(&tp->t_rstrt_ch);
2580 	seldestroy(&tp->t_rsel);
2581 	seldestroy(&tp->t_wsel);
2582 	pool_put(&tty_pool, tp);
2583 }
2584 
2585 /*
2586  * ttyprintf_nolock: send a message to a specific tty, without locking.
2587  *
2588  * => should be used only by tty driver or anything that knows the
2589  *    underlying tty will not be revoked(2)'d away.  [otherwise,
2590  *    use tprintf]
2591  */
2592 static void
2593 ttyprintf_nolock(struct tty *tp, const char *fmt, ...)
2594 {
2595 	va_list ap;
2596 
2597 	/* No mutex needed; going to process TTY. */
2598 	va_start(ap, fmt);
2599 	kprintf(fmt, TOTTY|NOLOCK, tp, NULL, ap);
2600 	va_end(ap);
2601 }
2602 
2603 /*
2604  * Initialize the tty subsystem.
2605  */
2606 void
2607 tty_init(void)
2608 {
2609 
2610 	mutex_init(&tty_lock, MUTEX_DEFAULT, IPL_VM);
2611 	tty_sigsih = softint_establish(SOFTINT_CLOCK, ttysigintr, NULL);
2612 	KASSERT(tty_sigsih != NULL);
2613 }
2614 
2615 /*
2616  * Send a signal from a tty to its process group or session leader.
2617  * Handoff to the target is deferred to a soft interrupt.
2618  */
2619 void
2620 ttysig(struct tty *tp, enum ttysigtype st, int sig)
2621 {
2622 	sigset_t *sp;
2623 
2624 	/* XXXSMP not yet KASSERT(mutex_owned(&tty_lock)); */
2625 
2626 	sp = &tp->t_sigs[st];
2627 	if (sigismember(sp, sig))
2628 		return;
2629 	sigaddset(sp, sig);
2630 	if (tp->t_sigcount++ == 0)
2631 		TAILQ_INSERT_TAIL(&tty_sigqueue, tp, t_sigqueue);
2632 	softint_schedule(tty_sigsih);
2633 }
2634 
2635 /*
2636  * Deliver deferred signals from ttys.  Note that the process groups
2637  * and sessions associated with the ttys may have changed from when
2638  * the signal was originally sent, but in practice it should not matter.
2639  * For signals produced as a result of a syscall, the soft interrupt
2640  * will fire before the syscall returns to the user.
2641  */
2642 static void
2643 ttysigintr(void *cookie)
2644 {
2645 	struct tty *tp;
2646 	enum ttysigtype st;
2647 	struct pgrp *pgrp;
2648 	struct session *sess;
2649 	int sig;
2650 
2651 	mutex_enter(&proclist_lock);
2652 	for (;;) {
2653 		mutex_spin_enter(&tty_lock);
2654 		if ((tp = TAILQ_FIRST(&tty_sigqueue)) == NULL) {
2655 			mutex_spin_exit(&tty_lock);
2656 			break;
2657 		}
2658 		KASSERT(tp->t_sigcount > 0);
2659 		for (st = 0; st < TTYSIG_COUNT; st++) {
2660 			if ((sig = firstsig(&tp->t_sigs[st])) != 0)
2661 				break;
2662 		}
2663 		KASSERT(st < TTYSIG_COUNT);
2664 		sigdelset(&tp->t_sigs[st], sig);
2665 		if (--tp->t_sigcount == 0)
2666 			TAILQ_REMOVE(&tty_sigqueue, tp, t_sigqueue);
2667 		pgrp = tp->t_pgrp;
2668 		sess = tp->t_session;
2669 		mutex_spin_exit(&tty_lock);
2670 		if (sig == 0)
2671 			panic("ttysigintr");
2672 		mutex_enter(&proclist_mutex);
2673 		switch (st) {
2674 		case TTYSIG_PG1:
2675 			if (pgrp != NULL)
2676 				pgsignal(pgrp, sig, 1);
2677 			break;
2678 		case TTYSIG_PG2:
2679 			if (pgrp != NULL)
2680 				pgsignal(pgrp, sig, sess != NULL);
2681 			break;
2682 		case TTYSIG_LEADER:
2683 			if (sess != NULL && sess->s_leader != NULL)
2684 				psignal(sess->s_leader, sig);
2685 			break;
2686 		default:
2687 			/* NOTREACHED */
2688 			break;
2689 		}
2690 		mutex_exit(&proclist_mutex);
2691 	}
2692 	mutex_exit(&proclist_lock);
2693 }
2694