xref: /netbsd-src/sys/kern/tty.c (revision cac8e449158efc7261bebc8657cbb0125a2cfdde)
1 /*	$NetBSD: tty.c,v 1.226 2008/07/31 01:46:40 uebayasi Exp $	*/
2 
3 /*-
4  * Copyright (c) 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  * POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /*-
30  * Copyright (c) 1982, 1986, 1990, 1991, 1993
31  *	The Regents of the University of California.  All rights reserved.
32  * (c) UNIX System Laboratories, Inc.
33  * All or some portions of this file are derived from material licensed
34  * to the University of California by American Telephone and Telegraph
35  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
36  * the permission of UNIX System Laboratories, Inc.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. Neither the name of the University nor the names of its contributors
47  *    may be used to endorse or promote products derived from this software
48  *    without specific prior written permission.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  *
62  *	@(#)tty.c	8.13 (Berkeley) 1/9/95
63  */
64 
65 #include <sys/cdefs.h>
66 __KERNEL_RCSID(0, "$NetBSD: tty.c,v 1.226 2008/07/31 01:46:40 uebayasi Exp $");
67 
68 #include <sys/param.h>
69 #include <sys/systm.h>
70 #include <sys/ioctl.h>
71 #include <sys/proc.h>
72 #define	TTYDEFCHARS
73 #include <sys/tty.h>
74 #undef	TTYDEFCHARS
75 #include <sys/file.h>
76 #include <sys/conf.h>
77 #include <sys/dkstat.h>
78 #include <sys/uio.h>
79 #include <sys/kernel.h>
80 #include <sys/vnode.h>
81 #include <sys/syslog.h>
82 #include <sys/malloc.h>
83 #include <sys/kmem.h>
84 #include <sys/signalvar.h>
85 #include <sys/resourcevar.h>
86 #include <sys/poll.h>
87 #include <sys/kprintf.h>
88 #include <sys/namei.h>
89 #include <sys/sysctl.h>
90 #include <sys/kauth.h>
91 #include <sys/intr.h>
92 
93 #include <machine/stdarg.h>
94 
95 static int	ttnread(struct tty *);
96 static void	ttyblock(struct tty *);
97 static void	ttyecho(int, struct tty *);
98 static void	ttyrubo(struct tty *, int);
99 static void	ttyprintf_nolock(struct tty *, const char *fmt, ...)
100     __attribute__((__format__(__printf__,2,3)));
101 static int	proc_compare(struct proc *, struct proc *);
102 static void	ttysigintr(void *);
103 
104 /* Symbolic sleep message strings. */
105 const char	ttclos[] = "ttycls";
106 const char	ttopen[] = "ttyopn";
107 const char	ttybg[] = "ttybg";
108 const char	ttyin[] = "ttyin";
109 const char	ttyout[] = "ttyout";
110 
111 /*
112  * Used to determine whether we still have a connection.  This is true in
113  * one of 3 cases:
114  * 1) We have carrier.
115  * 2) It's a locally attached terminal, and we are therefore ignoring carrier.
116  * 3) We're using a flow control mechanism that overloads the carrier signal.
117  */
118 #define	CONNECTED(tp)	(ISSET(tp->t_state, TS_CARR_ON) ||	\
119 			 ISSET(tp->t_cflag, CLOCAL | MDMBUF))
120 
121 /*
122  * Table with character classes and parity. The 8th bit indicates parity,
123  * the 7th bit indicates the character is an alphameric or underscore (for
124  * ALTWERASE), and the low 6 bits indicate delay type.  If the low 6 bits
125  * are 0 then the character needs no special processing on output; classes
126  * other than 0 might be translated or (not currently) require delays.
127  */
128 #define	E	0x00	/* Even parity. */
129 #define	O	0x80	/* Odd parity. */
130 #define	PARITY(c)	(char_type[c] & O)
131 
132 #define	ALPHA	0x40	/* Alpha or underscore. */
133 #define	ISALPHA(c)	(char_type[(c) & TTY_CHARMASK] & ALPHA)
134 
135 #define	CCLASSMASK	0x3f
136 #define	CCLASS(c)	(char_type[c] & CCLASSMASK)
137 
138 #define	BS	BACKSPACE
139 #define	CC	CONTROL
140 #define	CR	RETURN
141 #define	NA	ORDINARY | ALPHA
142 #define	NL	NEWLINE
143 #define	NO	ORDINARY
144 #define	TB	TAB
145 #define	VT	VTAB
146 
147 unsigned char const char_type[] = {
148 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* nul - bel */
149 	O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC,	/* bs - si */
150 	O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC,	/* dle - etb */
151 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* can - us */
152 	O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO,	/* sp - ' */
153 	E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO,	/* ( - / */
154 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* 0 - 7 */
155 	O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO,	/* 8 - ? */
156 	O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* @ - G */
157 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* H - O */
158 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* P - W */
159 	O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA,	/* X - _ */
160 	E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* ` - g */
161 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* h - o */
162 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* p - w */
163 	E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC,	/* x - del */
164 	/*
165 	 * Meta chars; should be settable per character set;
166 	 * for now, treat them all as normal characters.
167 	 */
168 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
169 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
170 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
171 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
172 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
173 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
174 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
175 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
176 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
177 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
178 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
179 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
180 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
181 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
182 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
183 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
184 };
185 #undef	BS
186 #undef	CC
187 #undef	CR
188 #undef	NA
189 #undef	NL
190 #undef	NO
191 #undef	TB
192 #undef	VT
193 
194 static struct ttylist_head tty_sigqueue = TAILQ_HEAD_INITIALIZER(tty_sigqueue);
195 static void *tty_sigsih;
196 
197 struct ttylist_head ttylist = TAILQ_HEAD_INITIALIZER(ttylist);
198 int tty_count;
199 kmutex_t tty_lock;
200 
201 uint64_t tk_cancc;
202 uint64_t tk_nin;
203 uint64_t tk_nout;
204 uint64_t tk_rawcc;
205 
206 SYSCTL_SETUP(sysctl_kern_tkstat_setup, "sysctl kern.tkstat subtree setup")
207 {
208 
209 	sysctl_createv(clog, 0, NULL, NULL,
210 		       CTLFLAG_PERMANENT,
211 		       CTLTYPE_NODE, "kern", NULL,
212 		       NULL, 0, NULL, 0,
213 		       CTL_KERN, CTL_EOL);
214 	sysctl_createv(clog, 0, NULL, NULL,
215 		       CTLFLAG_PERMANENT,
216 		       CTLTYPE_NODE, "tkstat",
217 		       SYSCTL_DESCR("Number of characters sent and and "
218 				    "received on ttys"),
219 		       NULL, 0, NULL, 0,
220 		       CTL_KERN, KERN_TKSTAT, CTL_EOL);
221 
222 	sysctl_createv(clog, 0, NULL, NULL,
223 		       CTLFLAG_PERMANENT,
224 		       CTLTYPE_QUAD, "nin",
225 		       SYSCTL_DESCR("Total number of tty input characters"),
226 		       NULL, 0, &tk_nin, 0,
227 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_NIN, CTL_EOL);
228 	sysctl_createv(clog, 0, NULL, NULL,
229 		       CTLFLAG_PERMANENT,
230 		       CTLTYPE_QUAD, "nout",
231 		       SYSCTL_DESCR("Total number of tty output characters"),
232 		       NULL, 0, &tk_nout, 0,
233 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_NOUT, CTL_EOL);
234 	sysctl_createv(clog, 0, NULL, NULL,
235 		       CTLFLAG_PERMANENT,
236 		       CTLTYPE_QUAD, "cancc",
237 		       SYSCTL_DESCR("Number of canonical tty input characters"),
238 		       NULL, 0, &tk_cancc, 0,
239 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_CANCC, CTL_EOL);
240 	sysctl_createv(clog, 0, NULL, NULL,
241 		       CTLFLAG_PERMANENT,
242 		       CTLTYPE_QUAD, "rawcc",
243 		       SYSCTL_DESCR("Number of raw tty input characters"),
244 		       NULL, 0, &tk_rawcc, 0,
245 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_RAWCC, CTL_EOL);
246 }
247 
248 int
249 ttyopen(struct tty *tp, int dialout, int nonblock)
250 {
251 	int	error;
252 
253 	error = 0;
254 
255 	mutex_spin_enter(&tty_lock);
256 
257 	if (dialout) {
258 		/*
259 		 * If the device is already open for non-dialout, fail.
260 		 * Otherwise, set TS_DIALOUT to block any pending non-dialout
261 		 * opens.
262 		 */
263 		if (ISSET(tp->t_state, TS_ISOPEN) &&
264 		    !ISSET(tp->t_state, TS_DIALOUT)) {
265 			error = EBUSY;
266 			goto out;
267 		}
268 		SET(tp->t_state, TS_DIALOUT);
269 	} else {
270 		if (!nonblock) {
271 			/*
272 			 * Wait for carrier.  Also wait for any dialout
273 			 * processes to close the tty first.
274 			 */
275 			while (ISSET(tp->t_state, TS_DIALOUT) ||
276 			       !CONNECTED(tp)) {
277 				tp->t_wopen++;
278 				error = ttysleep(tp, &tp->t_rawcv, true, 0);
279 				tp->t_wopen--;
280 				if (error)
281 					goto out;
282 			}
283 		} else {
284 			/*
285 			 * Don't allow a non-blocking non-dialout open if the
286 			 * device is already open for dialout.
287 			 */
288 			if (ISSET(tp->t_state, TS_DIALOUT)) {
289 				error = EBUSY;
290 				goto out;
291 			}
292 		}
293 	}
294 
295 out:
296 	mutex_spin_exit(&tty_lock);
297 	return (error);
298 }
299 
300 /*
301  * Initial open of tty, or (re)entry to standard tty line discipline.
302  */
303 int
304 ttylopen(dev_t device, struct tty *tp)
305 {
306 
307 	mutex_spin_enter(&tty_lock);
308 	tp->t_dev = device;
309 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
310 		SET(tp->t_state, TS_ISOPEN);
311 		memset(&tp->t_winsize, 0, sizeof(tp->t_winsize));
312 #ifdef COMPAT_OLDTTY
313 		tp->t_flags = 0;
314 #endif
315 	}
316 	mutex_spin_exit(&tty_lock);
317 	return (0);
318 }
319 
320 /*
321  * Handle close() on a tty line: flush and set to initial state,
322  * bumping generation number so that pending read/write calls
323  * can detect recycling of the tty.
324  */
325 int
326 ttyclose(struct tty *tp)
327 {
328 	extern struct tty *constty;	/* Temporary virtual console. */
329 	struct session *sess;
330 
331 	mutex_spin_enter(&tty_lock);
332 
333 	if (constty == tp)
334 		constty = NULL;
335 
336 	ttyflush(tp, FREAD | FWRITE);
337 
338 	tp->t_gen++;
339 	tp->t_pgrp = NULL;
340 	tp->t_state = 0;
341 	sess = tp->t_session;
342 	tp->t_session = NULL;
343 
344 	mutex_spin_exit(&tty_lock);
345 
346 	mutex_enter(proc_lock);
347 	if (sess != NULL)
348 		SESSRELE(sess);
349 	mutex_exit(proc_lock);
350 
351 	return (0);
352 }
353 
354 #define	FLUSHQ(q) {							\
355 	if ((q)->c_cc)							\
356 		ndflush(q, (q)->c_cc);					\
357 }
358 
359 /*
360  * This macro is used in canonical mode input processing, where a read
361  * request shall not return unless a 'line delimiter' ('\n') or 'break'
362  * (EOF, EOL, EOL2) character (or a signal) has been received. As EOL2
363  * is an extension to the POSIX.1 defined set of special characters,
364  * recognize it only if IEXTEN is set in the set of local flags.
365  */
366 #define	TTBREAKC(c, lflg)						\
367 	((c) == '\n' || (((c) == cc[VEOF] || (c) == cc[VEOL] ||		\
368 	((c) == cc[VEOL2] && ISSET(lflg, IEXTEN))) && (c) != _POSIX_VDISABLE))
369 
370 
371 
372 /*
373  * ttyinput() helper.
374  * Call with the tty lock held.
375  */
376 static int
377 ttyinput_wlock(int c, struct tty *tp)
378 {
379 	int	iflag, lflag, i, error;
380 	u_char	*cc;
381 
382 	KASSERT(mutex_owned(&tty_lock));
383 
384 	/*
385 	 * If input is pending take it first.
386 	 */
387 	lflag = tp->t_lflag;
388 	if (ISSET(lflag, PENDIN))
389 		ttypend(tp);
390 	/*
391 	 * Gather stats.
392 	 */
393 	if (ISSET(lflag, ICANON)) {
394 		++tk_cancc;
395 		++tp->t_cancc;
396 	} else {
397 		++tk_rawcc;
398 		++tp->t_rawcc;
399 	}
400 	++tk_nin;
401 
402 	cc = tp->t_cc;
403 
404 	/*
405 	 * Handle exceptional conditions (break, parity, framing).
406 	 */
407 	iflag = tp->t_iflag;
408 	if ((error = (ISSET(c, TTY_ERRORMASK))) != 0) {
409 		CLR(c, TTY_ERRORMASK);
410 		if (ISSET(error, TTY_FE) && c == 0) {		/* Break. */
411 			if (ISSET(iflag, IGNBRK))
412 				return (0);
413 			else if (ISSET(iflag, BRKINT)) {
414 				ttyflush(tp, FREAD | FWRITE);
415 				ttysig(tp, TTYSIG_PG1, SIGINT);
416 				return (0);
417 			} else if (ISSET(iflag, PARMRK))
418 				goto parmrk;
419 		} else if ((ISSET(error, TTY_PE) && ISSET(iflag, INPCK)) ||
420 		    ISSET(error, TTY_FE)) {
421 			if (ISSET(iflag, IGNPAR))
422 				return (0);
423 			else if (ISSET(iflag, PARMRK)) {
424  parmrk:			(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
425 				(void)putc(0    | TTY_QUOTE, &tp->t_rawq);
426 				(void)putc(c    | TTY_QUOTE, &tp->t_rawq);
427 				return (0);
428 			} else
429 				c = 0;
430 		}
431 	} else if (c == 0377 &&
432 	    ISSET(iflag, ISTRIP|IGNPAR|INPCK|PARMRK) == (INPCK|PARMRK)) {
433 		/* "Escape" a valid character of '\377'. */
434 		(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
435 		(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
436 		goto endcase;
437 	}
438 
439 	/*
440 	 * In tandem mode, check high water mark.
441 	 */
442 	if (ISSET(iflag, IXOFF) || ISSET(tp->t_cflag, CHWFLOW))
443 		ttyblock(tp);
444 	if (!ISSET(tp->t_state, TS_TYPEN) && ISSET(iflag, ISTRIP))
445 		CLR(c, 0x80);
446 	if (!ISSET(lflag, EXTPROC)) {
447 		/*
448 		 * Check for literal nexting very first
449 		 */
450 		if (ISSET(tp->t_state, TS_LNCH)) {
451 			SET(c, TTY_QUOTE);
452 			CLR(tp->t_state, TS_LNCH);
453 		}
454 		/*
455 		 * Scan for special characters.  This code
456 		 * is really just a big case statement with
457 		 * non-constant cases.  The bottom of the
458 		 * case statement is labeled ``endcase'', so goto
459 		 * it after a case match, or similar.
460 		 */
461 
462 		/*
463 		 * Control chars which aren't controlled
464 		 * by ICANON, ISIG, or IXON.
465 		 */
466 		if (ISSET(lflag, IEXTEN)) {
467 			if (CCEQ(cc[VLNEXT], c)) {
468 				if (ISSET(lflag, ECHO)) {
469 					if (ISSET(lflag, ECHOE)) {
470 						(void)ttyoutput('^', tp);
471 						(void)ttyoutput('\b', tp);
472 					} else
473 						ttyecho(c, tp);
474 				}
475 				SET(tp->t_state, TS_LNCH);
476 				goto endcase;
477 			}
478 			if (CCEQ(cc[VDISCARD], c)) {
479 				if (ISSET(lflag, FLUSHO))
480 					CLR(tp->t_lflag, FLUSHO);
481 				else {
482 					ttyflush(tp, FWRITE);
483 					ttyecho(c, tp);
484 					if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
485 						ttyretype(tp);
486 					SET(tp->t_lflag, FLUSHO);
487 				}
488 				goto startoutput;
489 			}
490 		}
491 		/*
492 		 * Signals.
493 		 */
494 		if (ISSET(lflag, ISIG)) {
495 			if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
496 				if (!ISSET(lflag, NOFLSH))
497 					ttyflush(tp, FREAD | FWRITE);
498 				ttyecho(c, tp);
499 				ttysig(tp, TTYSIG_PG1, CCEQ(cc[VINTR], c) ?
500 				    SIGINT : SIGQUIT);
501 				goto endcase;
502 			}
503 			if (CCEQ(cc[VSUSP], c)) {
504 				if (!ISSET(lflag, NOFLSH))
505 					ttyflush(tp, FREAD);
506 				ttyecho(c, tp);
507 				ttysig(tp, TTYSIG_PG1, SIGTSTP);
508 				goto endcase;
509 			}
510 		}
511 		/*
512 		 * Handle start/stop characters.
513 		 */
514 		if (ISSET(iflag, IXON)) {
515 			if (CCEQ(cc[VSTOP], c)) {
516 				if (!ISSET(tp->t_state, TS_TTSTOP)) {
517 					SET(tp->t_state, TS_TTSTOP);
518 					cdev_stop(tp, 0);
519 					return (0);
520 				}
521 				if (!CCEQ(cc[VSTART], c))
522 					return (0);
523 				/*
524 				 * if VSTART == VSTOP then toggle
525 				 */
526 				goto endcase;
527 			}
528 			if (CCEQ(cc[VSTART], c))
529 				goto restartoutput;
530 		}
531 		/*
532 		 * IGNCR, ICRNL, & INLCR
533 		 */
534 		if (c == '\r') {
535 			if (ISSET(iflag, IGNCR))
536 				goto endcase;
537 			else if (ISSET(iflag, ICRNL))
538 				c = '\n';
539 		} else if (c == '\n' && ISSET(iflag, INLCR))
540 			c = '\r';
541 	}
542 	if (!ISSET(lflag, EXTPROC) && ISSET(lflag, ICANON)) {
543 		/*
544 		 * From here on down canonical mode character
545 		 * processing takes place.
546 		 */
547 		/*
548 		 * erase (^H / ^?)
549 		 */
550 		if (CCEQ(cc[VERASE], c)) {
551 			if (tp->t_rawq.c_cc)
552 				ttyrub(unputc(&tp->t_rawq), tp);
553 			goto endcase;
554 		}
555 		/*
556 		 * kill (^U)
557 		 */
558 		if (CCEQ(cc[VKILL], c)) {
559 			if (ISSET(lflag, ECHOKE) &&
560 			    tp->t_rawq.c_cc == tp->t_rocount &&
561 			    !ISSET(lflag, ECHOPRT))
562 				while (tp->t_rawq.c_cc)
563 					ttyrub(unputc(&tp->t_rawq), tp);
564 			else {
565 				ttyecho(c, tp);
566 				if (ISSET(lflag, ECHOK) ||
567 				    ISSET(lflag, ECHOKE))
568 					ttyecho('\n', tp);
569 				FLUSHQ(&tp->t_rawq);
570 				tp->t_rocount = 0;
571 			}
572 			CLR(tp->t_state, TS_LOCAL);
573 			goto endcase;
574 		}
575 		/*
576 		 * Extensions to the POSIX.1 GTI set of functions.
577 		 */
578 		if (ISSET(lflag, IEXTEN)) {
579 			/*
580 			 * word erase (^W)
581 			 */
582 			if (CCEQ(cc[VWERASE], c)) {
583 				int alt = ISSET(lflag, ALTWERASE);
584 				int ctype;
585 
586 				/*
587 				 * erase whitespace
588 				 */
589 				while ((c = unputc(&tp->t_rawq)) == ' ' ||
590 				    c == '\t')
591 					ttyrub(c, tp);
592 				if (c == -1)
593 					goto endcase;
594 				/*
595 				 * erase last char of word and remember the
596 				 * next chars type (for ALTWERASE)
597 				 */
598 				ttyrub(c, tp);
599 				c = unputc(&tp->t_rawq);
600 				if (c == -1)
601 					goto endcase;
602 				if (c == ' ' || c == '\t') {
603 					(void)putc(c, &tp->t_rawq);
604 					goto endcase;
605 				}
606 				ctype = ISALPHA(c);
607 				/*
608 				 * erase rest of word
609 				 */
610 				do {
611 					ttyrub(c, tp);
612 					c = unputc(&tp->t_rawq);
613 					if (c == -1)
614 						goto endcase;
615 				} while (c != ' ' && c != '\t' &&
616 				    (alt == 0 || ISALPHA(c) == ctype));
617 				(void)putc(c, &tp->t_rawq);
618 				goto endcase;
619 			}
620 			/*
621 			 * reprint line (^R)
622 			 */
623 			if (CCEQ(cc[VREPRINT], c)) {
624 				ttyretype(tp);
625 				goto endcase;
626 			}
627 			/*
628 			 * ^T - kernel info and generate SIGINFO
629 			 */
630 			if (CCEQ(cc[VSTATUS], c)) {
631 				ttysig(tp, TTYSIG_PG1, SIGINFO);
632 				goto endcase;
633 			}
634 		}
635 	}
636 	/*
637 	 * Check for input buffer overflow
638 	 */
639 	if (tp->t_rawq.c_cc + tp->t_canq.c_cc >= TTYHOG) {
640 		if (ISSET(iflag, IMAXBEL)) {
641 			if (tp->t_outq.c_cc < tp->t_hiwat)
642 				(void)ttyoutput(CTRL('g'), tp);
643 		} else
644 			ttyflush(tp, FREAD | FWRITE);
645 		goto endcase;
646 	}
647 	/*
648 	 * Put data char in q for user and
649 	 * wakeup on seeing a line delimiter.
650 	 */
651 	if (putc(c, &tp->t_rawq) >= 0) {
652 		if (!ISSET(lflag, ICANON)) {
653 			ttwakeup(tp);
654 			ttyecho(c, tp);
655 			goto endcase;
656 		}
657 		if (TTBREAKC(c, lflag)) {
658 			tp->t_rocount = 0;
659 			catq(&tp->t_rawq, &tp->t_canq);
660 			ttwakeup(tp);
661 		} else if (tp->t_rocount++ == 0)
662 			tp->t_rocol = tp->t_column;
663 		if (ISSET(tp->t_state, TS_ERASE)) {
664 			/*
665 			 * end of prterase \.../
666 			 */
667 			CLR(tp->t_state, TS_ERASE);
668 			(void)ttyoutput('/', tp);
669 		}
670 		i = tp->t_column;
671 		ttyecho(c, tp);
672 		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ECHO)) {
673 			/*
674 			 * Place the cursor over the '^' of the ^D.
675 			 */
676 			i = min(2, tp->t_column - i);
677 			while (i > 0) {
678 				(void)ttyoutput('\b', tp);
679 				i--;
680 			}
681 		}
682 	}
683  endcase:
684 	/*
685 	 * IXANY means allow any character to restart output.
686 	 */
687 	if (ISSET(tp->t_state, TS_TTSTOP) &&
688 	    !ISSET(iflag, IXANY) && cc[VSTART] != cc[VSTOP]) {
689 		return (0);
690 	}
691  restartoutput:
692 	CLR(tp->t_lflag, FLUSHO);
693 	CLR(tp->t_state, TS_TTSTOP);
694  startoutput:
695 	return (ttstart(tp));
696 }
697 
698 /*
699  * Process input of a single character received on a tty.
700  *
701  * XXX - this is a hack, all drivers must changed to acquire the
702  *	 lock before calling linesw->l_rint()
703  */
704 int
705 ttyinput(int c, struct tty *tp)
706 {
707 	int error;
708 
709 	/*
710 	 * Unless the receiver is enabled, drop incoming data.
711 	 */
712 	if (!ISSET(tp->t_cflag, CREAD))
713 		return (0);
714 
715 	mutex_spin_enter(&tty_lock);
716 	error = ttyinput_wlock(c, tp);
717 	mutex_spin_exit(&tty_lock);
718 
719 	return (error);
720 }
721 
722 /*
723  * Output a single character on a tty, doing output processing
724  * as needed (expanding tabs, newline processing, etc.).
725  * Returns < 0 if succeeds, otherwise returns char to resend.
726  * Must be recursive.
727  *
728  * Call with tty lock held.
729  */
730 int
731 ttyoutput(int c, struct tty *tp)
732 {
733 	long	oflag;
734 	int	col, notout;
735 
736 	KASSERT(mutex_owned(&tty_lock));
737 
738 	oflag = tp->t_oflag;
739 	if (!ISSET(oflag, OPOST)) {
740 		tk_nout++;
741 		tp->t_outcc++;
742 		if (!ISSET(tp->t_lflag, FLUSHO) && putc(c, &tp->t_outq))
743 			return (c);
744 		return (-1);
745 	}
746 	/*
747 	 * Do tab expansion if OXTABS is set.  Special case if we do external
748 	 * processing, we don't do the tab expansion because we'll probably
749 	 * get it wrong.  If tab expansion needs to be done, let it happen
750 	 * externally.
751 	 */
752 	CLR(c, ~TTY_CHARMASK);
753 	if (c == '\t' &&
754 	    ISSET(oflag, OXTABS) && !ISSET(tp->t_lflag, EXTPROC)) {
755 		c = 8 - (tp->t_column & 7);
756 		if (ISSET(tp->t_lflag, FLUSHO)) {
757 			notout = 0;
758 		} else {
759 			notout = b_to_q("        ", c, &tp->t_outq);
760 			c -= notout;
761 			tk_nout += c;
762 			tp->t_outcc += c;
763 		}
764 		tp->t_column += c;
765 		return (notout ? '\t' : -1);
766 	}
767 	if (c == CEOT && ISSET(oflag, ONOEOT))
768 		return (-1);
769 
770 	/*
771 	 * Newline translation: if ONLCR is set,
772 	 * translate newline into "\r\n".
773 	 */
774 	if (c == '\n' && ISSET(tp->t_oflag, ONLCR)) {
775 		tk_nout++;
776 		tp->t_outcc++;
777 		if (!ISSET(tp->t_lflag, FLUSHO) && putc('\r', &tp->t_outq))
778 			return (c);
779 	}
780 	/* If OCRNL is set, translate "\r" into "\n". */
781 	else if (c == '\r' && ISSET(tp->t_oflag, OCRNL))
782 		c = '\n';
783 	/* If ONOCR is set, don't transmit CRs when on column 0. */
784 	else if (c == '\r' && ISSET(tp->t_oflag, ONOCR) && tp->t_column == 0)
785 		return (-1);
786 
787 	tk_nout++;
788 	tp->t_outcc++;
789 	if (!ISSET(tp->t_lflag, FLUSHO) && putc(c, &tp->t_outq))
790 		return (c);
791 
792 	col = tp->t_column;
793 	switch (CCLASS(c)) {
794 	case BACKSPACE:
795 		if (col > 0)
796 			--col;
797 		break;
798 	case CONTROL:
799 		break;
800 	case NEWLINE:
801 		if (ISSET(tp->t_oflag, ONLCR | ONLRET))
802 			col = 0;
803 		break;
804 	case RETURN:
805 		col = 0;
806 		break;
807 	case ORDINARY:
808 		++col;
809 		break;
810 	case TAB:
811 		col = (col + 8) & ~7;
812 		break;
813 	}
814 	tp->t_column = col;
815 	return (-1);
816 }
817 
818 /*
819  * Ioctls for all tty devices.  Called after line-discipline specific ioctl
820  * has been called to do discipline-specific functions and/or reject any
821  * of these ioctl commands.
822  */
823 /* ARGSUSED */
824 int
825 ttioctl(struct tty *tp, u_long cmd, void *data, int flag, struct lwp *l)
826 {
827 	extern struct tty *constty;	/* Temporary virtual console. */
828 	struct proc *p = l ? l->l_proc : NULL;
829 	struct linesw	*lp;
830 	int		s, error;
831 	struct nameidata nd;
832 	char		infobuf[200];
833 
834 	/* If the ioctl involves modification, hang if in the background. */
835 	switch (cmd) {
836 	case  TIOCFLUSH:
837 	case  TIOCDRAIN:
838 	case  TIOCSBRK:
839 	case  TIOCCBRK:
840 	case  TIOCSTART:
841 	case  TIOCSETA:
842 	case  TIOCSETD:
843 	case  TIOCSLINED:
844 	case  TIOCSETAF:
845 	case  TIOCSETAW:
846 #ifdef notdef
847 	case  TIOCSPGRP:
848 	case  FIOSETOWN:
849 #endif
850 	case  TIOCSTAT:
851 	case  TIOCSTI:
852 	case  TIOCSWINSZ:
853 #ifdef COMPAT_OLDTTY
854 	case  TIOCLBIC:
855 	case  TIOCLBIS:
856 	case  TIOCLSET:
857 	case  TIOCSETC:
858 	case OTIOCSETD:
859 	case  TIOCSETN:
860 	case  TIOCSETP:
861 	case  TIOCSLTC:
862 #endif
863 		mutex_spin_enter(&tty_lock);
864 		while (isbackground(curproc, tp) &&
865 		    p->p_pgrp->pg_jobc && (p->p_lflag & PL_PPWAIT) == 0 &&
866 		    !sigismasked(l, SIGTTOU)) {
867 			mutex_spin_exit(&tty_lock);
868 
869 			mutex_enter(proc_lock);
870 			pgsignal(p->p_pgrp, SIGTTOU, 1);
871 			mutex_exit(proc_lock);
872 
873 			mutex_spin_enter(&tty_lock);
874 			error = ttysleep(tp, &lbolt, true, 0);
875 			if (error) {
876 				mutex_spin_exit(&tty_lock);
877 				return (error);
878 			}
879 		}
880 		mutex_spin_exit(&tty_lock);
881 		break;
882 	}
883 
884 	switch (cmd) {			/* Process the ioctl. */
885 	case FIOASYNC:			/* set/clear async i/o */
886 		mutex_spin_enter(&tty_lock);
887 		if (*(int *)data)
888 			SET(tp->t_state, TS_ASYNC);
889 		else
890 			CLR(tp->t_state, TS_ASYNC);
891 		mutex_spin_exit(&tty_lock);
892 		break;
893 	case FIONBIO:			/* set/clear non-blocking i/o */
894 		break;			/* XXX: delete. */
895 	case FIONREAD:			/* get # bytes to read */
896 		mutex_spin_enter(&tty_lock);
897 		*(int *)data = ttnread(tp);
898 		mutex_spin_exit(&tty_lock);
899 		break;
900 	case FIONWRITE:			/* get # bytes to written & unsent */
901 		mutex_spin_enter(&tty_lock);
902 		*(int *)data = tp->t_outq.c_cc;
903 		mutex_spin_exit(&tty_lock);
904 		break;
905 	case FIONSPACE:			/* get # bytes to written & unsent */
906 		mutex_spin_enter(&tty_lock);
907 		*(int *)data = tp->t_outq.c_cn - tp->t_outq.c_cc;
908 		mutex_spin_exit(&tty_lock);
909 		break;
910 	case TIOCEXCL:			/* set exclusive use of tty */
911 		mutex_spin_enter(&tty_lock);
912 		SET(tp->t_state, TS_XCLUDE);
913 		mutex_spin_exit(&tty_lock);
914 		break;
915 	case TIOCFLUSH: {		/* flush buffers */
916 		int flags = *(int *)data;
917 
918 		if (flags == 0)
919 			flags = FREAD | FWRITE;
920 		else
921 			flags &= FREAD | FWRITE;
922 		mutex_spin_enter(&tty_lock);
923 		ttyflush(tp, flags);
924 		mutex_spin_exit(&tty_lock);
925 		break;
926 	}
927 	case TIOCCONS:			/* become virtual console */
928 		if (*(int *)data) {
929 			if (constty && constty != tp &&
930 			    ISSET(constty->t_state, TS_CARR_ON | TS_ISOPEN) ==
931 			    (TS_CARR_ON | TS_ISOPEN))
932 				return EBUSY;
933 
934 			NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
935 			    "/dev/console");
936 			if ((error = namei(&nd)) != 0)
937 				return error;
938 			error = VOP_ACCESS(nd.ni_vp, VREAD, l->l_cred);
939 			vput(nd.ni_vp);
940 			if (error)
941 				return error;
942 
943 			constty = tp;
944 		} else if (tp == constty)
945 			constty = NULL;
946 		break;
947 	case TIOCDRAIN:			/* wait till output drained */
948 		if ((error = ttywait(tp)) != 0)
949 			return (error);
950 		break;
951 	case TIOCGETA: {		/* get termios struct */
952 		struct termios *t = (struct termios *)data;
953 
954 		memcpy(t, &tp->t_termios, sizeof(struct termios));
955 		break;
956 	}
957 	case TIOCGETD:			/* get line discipline (old) */
958 		*(int *)data = tp->t_linesw->l_no;
959 		break;
960 	case TIOCGLINED:		/* get line discipline (new) */
961 		(void)strncpy((char *)data, tp->t_linesw->l_name,
962 		    TTLINEDNAMELEN - 1);
963 		break;
964 	case TIOCGWINSZ:		/* get window size */
965 		*(struct winsize *)data = tp->t_winsize;
966 		break;
967 	case FIOGETOWN:
968 		mutex_enter(proc_lock);
969 		if (tp->t_session != NULL && !isctty(p, tp)) {
970 			mutex_exit(proc_lock);
971 			return (ENOTTY);
972 		}
973 		*(int *)data = tp->t_pgrp ? -tp->t_pgrp->pg_id : 0;
974 		mutex_exit(proc_lock);
975 		break;
976 	case TIOCGPGRP:			/* get pgrp of tty */
977 		mutex_enter(proc_lock);
978 		if (!isctty(p, tp)) {
979 			mutex_exit(proc_lock);
980 			return (ENOTTY);
981 		}
982 		*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PGID;
983 		mutex_exit(proc_lock);
984 		break;
985 	case TIOCGSID:			/* get sid of tty */
986 		mutex_enter(proc_lock);
987 		if (!isctty(p, tp)) {
988 			mutex_exit(proc_lock);
989 			return (ENOTTY);
990 		}
991 		*(int *)data = tp->t_session->s_sid;
992 		mutex_exit(proc_lock);
993 		break;
994 #ifdef TIOCHPCL
995 	case TIOCHPCL:			/* hang up on last close */
996 		mutex_spin_enter(&tty_lock);
997 		SET(tp->t_cflag, HUPCL);
998 		mutex_spin_exit(&tty_lock);
999 		break;
1000 #endif
1001 	case TIOCNXCL:			/* reset exclusive use of tty */
1002 		mutex_spin_enter(&tty_lock);
1003 		CLR(tp->t_state, TS_XCLUDE);
1004 		mutex_spin_exit(&tty_lock);
1005 		break;
1006 	case TIOCOUTQ:			/* output queue size */
1007 		*(int *)data = tp->t_outq.c_cc;
1008 		break;
1009 	case TIOCSETA:			/* set termios struct */
1010 	case TIOCSETAW:			/* drain output, set */
1011 	case TIOCSETAF: {		/* drn out, fls in, set */
1012 		struct termios *t = (struct termios *)data;
1013 
1014 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1015 			if ((error = ttywait(tp)) != 0)
1016 				return (error);
1017 
1018 			if (cmd == TIOCSETAF) {
1019 				mutex_spin_enter(&tty_lock);
1020 				ttyflush(tp, FREAD);
1021 				mutex_spin_exit(&tty_lock);
1022 			}
1023 		}
1024 
1025 		s = spltty();
1026 		/*
1027 		 * XXXSMP - some drivers call back on us from t_param(), so
1028 		 *	    don't take the tty spin lock here.
1029 		 *	    require t_param() to unlock upon callback?
1030 		 */
1031 		/* wanted here: mutex_spin_enter(&tty_lock); */
1032 		if (!ISSET(t->c_cflag, CIGNORE)) {
1033 			/*
1034 			 * Set device hardware.
1035 			 */
1036 			if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
1037 				/* wanted here: mutex_spin_exit(&tty_lock); */
1038 				splx(s);
1039 				return (error);
1040 			} else {
1041 				tp->t_cflag = t->c_cflag;
1042 				tp->t_ispeed = t->c_ispeed;
1043 				tp->t_ospeed = t->c_ospeed;
1044 				if (t->c_ospeed == 0)
1045 					ttysig(tp, TTYSIG_LEADER, SIGHUP);
1046 			}
1047 			ttsetwater(tp);
1048 		}
1049 
1050 		/* delayed lock acquiring */
1051 		mutex_spin_enter(&tty_lock);
1052 		if (cmd != TIOCSETAF) {
1053 			if (ISSET(t->c_lflag, ICANON) !=
1054 			    ISSET(tp->t_lflag, ICANON)) {
1055 				if (ISSET(t->c_lflag, ICANON)) {
1056 					SET(tp->t_lflag, PENDIN);
1057 					ttwakeup(tp);
1058 				} else {
1059 					struct clist tq;
1060 
1061 					catq(&tp->t_rawq, &tp->t_canq);
1062 					tq = tp->t_rawq;
1063 					tp->t_rawq = tp->t_canq;
1064 					tp->t_canq = tq;
1065 					CLR(tp->t_lflag, PENDIN);
1066 				}
1067 			}
1068 		}
1069 		tp->t_iflag = t->c_iflag;
1070 		tp->t_oflag = t->c_oflag;
1071 		/*
1072 		 * Make the EXTPROC bit read only.
1073 		 */
1074 		if (ISSET(tp->t_lflag, EXTPROC))
1075 			SET(t->c_lflag, EXTPROC);
1076 		else
1077 			CLR(t->c_lflag, EXTPROC);
1078 		tp->t_lflag = t->c_lflag | ISSET(tp->t_lflag, PENDIN);
1079 		memcpy(tp->t_cc, t->c_cc, sizeof(t->c_cc));
1080 		mutex_spin_exit(&tty_lock);
1081 		splx(s);
1082 		break;
1083 	}
1084 	case TIOCSETD:			/* set line discipline (old) */
1085 		lp = ttyldisc_lookup_bynum(*(int *)data);
1086 		goto setldisc;
1087 
1088 	case TIOCSLINED: {		/* set line discipline (new) */
1089 		char *name = (char *)data;
1090 		dev_t device;
1091 
1092 		/* Null terminate to prevent buffer overflow */
1093 		name[TTLINEDNAMELEN - 1] = '\0';
1094 		lp = ttyldisc_lookup(name);
1095  setldisc:
1096 		if (lp == NULL)
1097 			return (ENXIO);
1098 
1099 		if (lp != tp->t_linesw) {
1100 			device = tp->t_dev;
1101 			s = spltty();
1102 			(*tp->t_linesw->l_close)(tp, flag);
1103 			error = (*lp->l_open)(device, tp);
1104 			if (error) {
1105 				(void)(*tp->t_linesw->l_open)(device, tp);
1106 				splx(s);
1107 				ttyldisc_release(lp);
1108 				return (error);
1109 			}
1110 			ttyldisc_release(tp->t_linesw);
1111 			tp->t_linesw = lp;
1112 			splx(s);
1113 		} else {
1114 			/* Drop extra reference. */
1115 			ttyldisc_release(lp);
1116 		}
1117 		break;
1118 	}
1119 	case TIOCSTART:			/* start output, like ^Q */
1120 		mutex_spin_enter(&tty_lock);
1121 		if (ISSET(tp->t_state, TS_TTSTOP) ||
1122 		    ISSET(tp->t_lflag, FLUSHO)) {
1123 			CLR(tp->t_lflag, FLUSHO);
1124 			CLR(tp->t_state, TS_TTSTOP);
1125 			ttstart(tp);
1126 		}
1127 		mutex_spin_exit(&tty_lock);
1128 		break;
1129 	case TIOCSTI:			/* simulate terminal input */
1130 		if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_STI,
1131 		    tp) != 0) {
1132 			if (!ISSET(flag, FREAD))
1133 				return (EPERM);
1134 			if (!isctty(p, tp))
1135 				return (EACCES);
1136 		}
1137 		(*tp->t_linesw->l_rint)(*(u_char *)data, tp);
1138 		break;
1139 	case TIOCSTOP:			/* stop output, like ^S */
1140 	{
1141 		mutex_spin_enter(&tty_lock);
1142 		if (!ISSET(tp->t_state, TS_TTSTOP)) {
1143 			SET(tp->t_state, TS_TTSTOP);
1144 			cdev_stop(tp, 0);
1145 		}
1146 		mutex_spin_exit(&tty_lock);
1147 		break;
1148 	}
1149 	case TIOCSCTTY:			/* become controlling tty */
1150 		mutex_enter(proc_lock);
1151 		mutex_spin_enter(&tty_lock);
1152 
1153 		/* Session ctty vnode pointer set in vnode layer. */
1154 		if (!SESS_LEADER(p) ||
1155 		    ((p->p_session->s_ttyvp || tp->t_session) &&
1156 		    (tp->t_session != p->p_session))) {
1157 			mutex_spin_exit(&tty_lock);
1158 			mutex_exit(proc_lock);
1159 			return (EPERM);
1160 		}
1161 
1162 		/*
1163 		 * `p_session' acquires a reference.
1164 		 * But note that if `t_session' is set at this point,
1165 		 * it must equal `p_session', in which case the session
1166 		 * already has the correct reference count.
1167 		 */
1168 		if (tp->t_session == NULL)
1169 			SESSHOLD(p->p_session);
1170 
1171 		tp->t_session = p->p_session;
1172 		tp->t_pgrp = p->p_pgrp;
1173 		p->p_session->s_ttyp = tp;
1174 		p->p_lflag |= PL_CONTROLT;
1175 		mutex_spin_exit(&tty_lock);
1176 		mutex_exit(proc_lock);
1177 		break;
1178 	case FIOSETOWN: {		/* set pgrp of tty */
1179 		pid_t pgid = *(int *)data;
1180 		struct pgrp *pgrp;
1181 
1182 		mutex_enter(proc_lock);
1183 		if (tp->t_session != NULL && !isctty(p, tp)) {
1184 			mutex_exit(proc_lock);
1185 			return (ENOTTY);
1186 		}
1187 
1188 		if (pgid < 0) {
1189 			pgrp = pg_find(-pgid, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
1190 			if (pgrp == NULL)
1191 				return (EINVAL);
1192 		} else {
1193 			struct proc *p1;
1194 			p1 = p_find(pgid, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
1195 			if (!p1)
1196 				return (ESRCH);
1197 			pgrp = p1->p_pgrp;
1198 		}
1199 
1200 		if (pgrp->pg_session != p->p_session) {
1201 			mutex_exit(proc_lock);
1202 			return (EPERM);
1203 		}
1204 		mutex_spin_enter(&tty_lock);
1205 		tp->t_pgrp = pgrp;
1206 		mutex_spin_exit(&tty_lock);
1207 		mutex_exit(proc_lock);
1208 		break;
1209 	}
1210 	case TIOCSPGRP: {		/* set pgrp of tty */
1211 		struct pgrp *pgrp;
1212 
1213 		mutex_enter(proc_lock);
1214 		if (!isctty(p, tp)) {
1215 			mutex_exit(proc_lock);
1216 			return (ENOTTY);
1217 		}
1218 		pgrp = pg_find(*(int *)data, PFIND_LOCKED | PFIND_UNLOCK_FAIL);
1219 		if (pgrp == NULL)
1220 			return (EINVAL);
1221 		if (pgrp->pg_session != p->p_session) {
1222 			mutex_exit(proc_lock);
1223 			return (EPERM);
1224 		}
1225 		mutex_spin_enter(&tty_lock);
1226 		tp->t_pgrp = pgrp;
1227 		mutex_spin_exit(&tty_lock);
1228 		mutex_exit(proc_lock);
1229 		break;
1230 	}
1231 	case TIOCSTAT:			/* get load avg stats */
1232 		mutex_enter(proc_lock);
1233 		ttygetinfo(tp, 0, infobuf, sizeof(infobuf));
1234 		mutex_exit(proc_lock);
1235 
1236 		mutex_spin_enter(&tty_lock);
1237 		ttyputinfo(tp, infobuf);
1238 		mutex_spin_exit(&tty_lock);
1239 		break;
1240 	case TIOCSWINSZ:		/* set window size */
1241 		mutex_spin_enter(&tty_lock);
1242 		if (memcmp((void *)&tp->t_winsize, data,
1243 		    sizeof(struct winsize))) {
1244 			tp->t_winsize = *(struct winsize *)data;
1245 			ttysig(tp, TTYSIG_PG1, SIGWINCH);
1246 		}
1247 		mutex_spin_exit(&tty_lock);
1248 		break;
1249 	default:
1250 #ifdef COMPAT_OLDTTY
1251 		return (ttcompat(tp, cmd, data, flag, l));
1252 #else
1253 		return (EPASSTHROUGH);
1254 #endif
1255 	}
1256 	return (0);
1257 }
1258 
1259 int
1260 ttpoll(struct tty *tp, int events, struct lwp *l)
1261 {
1262 	int	revents;
1263 
1264 	revents = 0;
1265 	mutex_spin_enter(&tty_lock);
1266 	if (events & (POLLIN | POLLRDNORM))
1267 		if (ttnread(tp) > 0)
1268 			revents |= events & (POLLIN | POLLRDNORM);
1269 
1270 	if (events & (POLLOUT | POLLWRNORM))
1271 		if (tp->t_outq.c_cc <= tp->t_lowat)
1272 			revents |= events & (POLLOUT | POLLWRNORM);
1273 
1274 	if (events & POLLHUP)
1275 		if (!CONNECTED(tp))
1276 			revents |= POLLHUP;
1277 
1278 	if (revents == 0) {
1279 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
1280 			selrecord(l, &tp->t_rsel);
1281 
1282 		if (events & (POLLOUT | POLLWRNORM))
1283 			selrecord(l, &tp->t_wsel);
1284 	}
1285 
1286 	mutex_spin_exit(&tty_lock);
1287 
1288 	return (revents);
1289 }
1290 
1291 static void
1292 filt_ttyrdetach(struct knote *kn)
1293 {
1294 	struct tty	*tp;
1295 
1296 	tp = kn->kn_hook;
1297 	mutex_spin_enter(&tty_lock);
1298 	SLIST_REMOVE(&tp->t_rsel.sel_klist, kn, knote, kn_selnext);
1299 	mutex_spin_exit(&tty_lock);
1300 }
1301 
1302 static int
1303 filt_ttyread(struct knote *kn, long hint)
1304 {
1305 	struct tty	*tp;
1306 
1307 	tp = kn->kn_hook;
1308 	if ((hint & NOTE_SUBMIT) == 0)
1309 		mutex_spin_enter(&tty_lock);
1310 	kn->kn_data = ttnread(tp);
1311 	if ((hint & NOTE_SUBMIT) == 0)
1312 		mutex_spin_exit(&tty_lock);
1313 	return (kn->kn_data > 0);
1314 }
1315 
1316 static void
1317 filt_ttywdetach(struct knote *kn)
1318 {
1319 	struct tty	*tp;
1320 
1321 	tp = kn->kn_hook;
1322 	mutex_spin_enter(&tty_lock);
1323 	SLIST_REMOVE(&tp->t_wsel.sel_klist, kn, knote, kn_selnext);
1324 	mutex_spin_exit(&tty_lock);
1325 }
1326 
1327 static int
1328 filt_ttywrite(struct knote *kn, long hint)
1329 {
1330 	struct tty	*tp;
1331 	int		canwrite;
1332 
1333 	tp = kn->kn_hook;
1334 	if ((hint & NOTE_SUBMIT) == 0)
1335 		mutex_spin_enter(&tty_lock);
1336 	kn->kn_data = tp->t_outq.c_cn - tp->t_outq.c_cc;
1337 	canwrite = (tp->t_outq.c_cc <= tp->t_lowat) && CONNECTED(tp);
1338 	if ((hint & NOTE_SUBMIT) == 0)
1339 		mutex_spin_exit(&tty_lock);
1340 	return (canwrite);
1341 }
1342 
1343 static const struct filterops ttyread_filtops =
1344 	{ 1, NULL, filt_ttyrdetach, filt_ttyread };
1345 static const struct filterops ttywrite_filtops =
1346 	{ 1, NULL, filt_ttywdetach, filt_ttywrite };
1347 
1348 int
1349 ttykqfilter(dev_t dev, struct knote *kn)
1350 {
1351 	struct tty	*tp;
1352 	struct klist	*klist;
1353 
1354 	if ((tp = cdev_tty(dev)) == NULL)
1355 		return (ENXIO);
1356 
1357 	switch (kn->kn_filter) {
1358 	case EVFILT_READ:
1359 		klist = &tp->t_rsel.sel_klist;
1360 		kn->kn_fop = &ttyread_filtops;
1361 		break;
1362 	case EVFILT_WRITE:
1363 		klist = &tp->t_wsel.sel_klist;
1364 		kn->kn_fop = &ttywrite_filtops;
1365 		break;
1366 	default:
1367 		return EINVAL;
1368 	}
1369 
1370 	kn->kn_hook = tp;
1371 
1372 	mutex_spin_enter(&tty_lock);
1373 	SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1374 	mutex_spin_exit(&tty_lock);
1375 
1376 	return (0);
1377 }
1378 
1379 /*
1380  * Find the number of chars ready to be read from this tty.
1381  * Call with the tty lock held.
1382  */
1383 static int
1384 ttnread(struct tty *tp)
1385 {
1386 	int	nread;
1387 
1388 	KASSERT(mutex_owned(&tty_lock));
1389 
1390 	if (ISSET(tp->t_lflag, PENDIN))
1391 		ttypend(tp);
1392 	nread = tp->t_canq.c_cc;
1393 	if (!ISSET(tp->t_lflag, ICANON)) {
1394 		nread += tp->t_rawq.c_cc;
1395 		if (nread < tp->t_cc[VMIN] && !tp->t_cc[VTIME])
1396 			nread = 0;
1397 	}
1398 	return (nread);
1399 }
1400 
1401 /*
1402  * Wait for output to drain.
1403  */
1404 int
1405 ttywait(struct tty *tp)
1406 {
1407 	int	error;
1408 
1409 	error = 0;
1410 
1411 	mutex_spin_enter(&tty_lock);
1412 	while ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1413 	    CONNECTED(tp) && tp->t_oproc) {
1414 		(*tp->t_oproc)(tp);
1415 		error = ttysleep(tp, &tp->t_outcv, true, 0);
1416 		if (error)
1417 			break;
1418 	}
1419 	mutex_spin_exit(&tty_lock);
1420 
1421 	return (error);
1422 }
1423 
1424 /*
1425  * Flush if successfully wait.
1426  */
1427 int
1428 ttywflush(struct tty *tp)
1429 {
1430 	int	error;
1431 
1432 	if ((error = ttywait(tp)) == 0) {
1433 		mutex_spin_enter(&tty_lock);
1434 		ttyflush(tp, FREAD);
1435 		mutex_spin_exit(&tty_lock);
1436 	}
1437 	return (error);
1438 }
1439 
1440 /*
1441  * Flush tty read and/or write queues, notifying anyone waiting.
1442  * Call with the tty lock held.
1443  */
1444 void
1445 ttyflush(struct tty *tp, int rw)
1446 {
1447 
1448 	KASSERT(mutex_owned(&tty_lock));
1449 
1450 	if (rw & FREAD) {
1451 		FLUSHQ(&tp->t_canq);
1452 		FLUSHQ(&tp->t_rawq);
1453 		tp->t_rocount = 0;
1454 		tp->t_rocol = 0;
1455 		CLR(tp->t_state, TS_LOCAL);
1456 		ttwakeup(tp);
1457 	}
1458 	if (rw & FWRITE) {
1459 		CLR(tp->t_state, TS_TTSTOP);
1460 		cdev_stop(tp, rw);
1461 		FLUSHQ(&tp->t_outq);
1462 		cv_broadcast(&tp->t_outcv);
1463 		selnotify(&tp->t_wsel, 0, NOTE_SUBMIT);
1464 	}
1465 }
1466 
1467 /*
1468  * Copy in the default termios characters.
1469  */
1470 void
1471 ttychars(struct tty *tp)
1472 {
1473 
1474 	memcpy(tp->t_cc, ttydefchars, sizeof(ttydefchars));
1475 }
1476 
1477 /*
1478  * Send stop character on input overflow.
1479  * Call with the tty lock held.
1480  */
1481 static void
1482 ttyblock(struct tty *tp)
1483 {
1484 	int	total;
1485 
1486 	KASSERT(mutex_owned(&tty_lock));
1487 
1488 	total = tp->t_rawq.c_cc + tp->t_canq.c_cc;
1489 	if (tp->t_rawq.c_cc > TTYHOG) {
1490 		ttyflush(tp, FREAD | FWRITE);
1491 		CLR(tp->t_state, TS_TBLOCK);
1492 	}
1493 	/*
1494 	 * Block further input iff: current input > threshold
1495 	 * AND input is available to user program.
1496 	 */
1497 	if (total >= TTYHOG / 2 &&
1498 	    !ISSET(tp->t_state, TS_TBLOCK) &&
1499 	    (!ISSET(tp->t_lflag, ICANON) || tp->t_canq.c_cc > 0)) {
1500 		if (ISSET(tp->t_iflag, IXOFF) &&
1501 		    tp->t_cc[VSTOP] != _POSIX_VDISABLE &&
1502 		    putc(tp->t_cc[VSTOP], &tp->t_outq) == 0) {
1503 			SET(tp->t_state, TS_TBLOCK);
1504 			ttstart(tp);
1505 		}
1506 		/* Try to block remote output via hardware flow control. */
1507 		if (ISSET(tp->t_cflag, CHWFLOW) && tp->t_hwiflow &&
1508 		    (*tp->t_hwiflow)(tp, 1) != 0)
1509 			SET(tp->t_state, TS_TBLOCK);
1510 	}
1511 }
1512 
1513 /*
1514  * Delayed line discipline output
1515  */
1516 void
1517 ttrstrt(void *tp_arg)
1518 {
1519 	struct tty	*tp;
1520 
1521 #ifdef DIAGNOSTIC
1522 	if (tp_arg == NULL)
1523 		panic("ttrstrt");
1524 #endif
1525 	tp = tp_arg;
1526 	mutex_spin_enter(&tty_lock);
1527 
1528 	CLR(tp->t_state, TS_TIMEOUT);
1529 	ttstart(tp); /* XXX - Shouldn't this be tp->l_start(tp)? */
1530 
1531 	mutex_spin_exit(&tty_lock);
1532 }
1533 
1534 /*
1535  * start a line discipline
1536  * Always call with tty lock held?
1537  */
1538 int
1539 ttstart(struct tty *tp)
1540 {
1541 
1542 	if (tp->t_oproc != NULL)	/* XXX: Kludge for pty. */
1543 		(*tp->t_oproc)(tp);
1544 	return (0);
1545 }
1546 
1547 /*
1548  * "close" a line discipline
1549  */
1550 int
1551 ttylclose(struct tty *tp, int flag)
1552 {
1553 
1554 	if (flag & FNONBLOCK) {
1555 		mutex_spin_enter(&tty_lock);
1556 		ttyflush(tp, FREAD | FWRITE);
1557 		mutex_spin_exit(&tty_lock);
1558 	} else
1559 		ttywflush(tp);
1560 	return (0);
1561 }
1562 
1563 /*
1564  * Handle modem control transition on a tty.
1565  * Flag indicates new state of carrier.
1566  * Returns 0 if the line should be turned off, otherwise 1.
1567  */
1568 int
1569 ttymodem(struct tty *tp, int flag)
1570 {
1571 
1572 	mutex_spin_enter(&tty_lock);
1573 	if (flag == 0) {
1574 		if (ISSET(tp->t_state, TS_CARR_ON)) {
1575 			/*
1576 			 * Lost carrier.
1577 			 */
1578 			CLR(tp->t_state, TS_CARR_ON);
1579 			if (ISSET(tp->t_state, TS_ISOPEN) && !CONNECTED(tp)) {
1580 				ttysig(tp, TTYSIG_LEADER, SIGHUP);
1581 				ttyflush(tp, FREAD | FWRITE);
1582 				mutex_spin_exit(&tty_lock);
1583 				return (0);
1584 			}
1585 		}
1586 	} else {
1587 		if (!ISSET(tp->t_state, TS_CARR_ON)) {
1588 			/*
1589 			 * Carrier now on.
1590 			 */
1591 			SET(tp->t_state, TS_CARR_ON);
1592 			ttwakeup(tp);
1593 		}
1594 	}
1595 	mutex_spin_exit(&tty_lock);
1596 
1597 	return (1);
1598 }
1599 
1600 /*
1601  * Default modem control routine (for other line disciplines).
1602  * Return argument flag, to turn off device on carrier drop.
1603  */
1604 int
1605 nullmodem(struct tty *tp, int flag)
1606 {
1607 
1608 	mutex_spin_enter(&tty_lock);
1609 	if (flag)
1610 		SET(tp->t_state, TS_CARR_ON);
1611 	else {
1612 		CLR(tp->t_state, TS_CARR_ON);
1613 		if (!CONNECTED(tp)) {
1614 			ttysig(tp, TTYSIG_LEADER, SIGHUP);
1615 			mutex_spin_exit(&tty_lock);
1616 			return (0);
1617 		}
1618 	}
1619 	mutex_spin_exit(&tty_lock);
1620 
1621 	return (1);
1622 }
1623 
1624 /*
1625  * Reinput pending characters after state switch.
1626  */
1627 void
1628 ttypend(struct tty *tp)
1629 {
1630 	struct clist	tq;
1631 	int		c;
1632 
1633 	KASSERT(mutex_owned(&tty_lock));
1634 
1635 	CLR(tp->t_lflag, PENDIN);
1636 	SET(tp->t_state, TS_TYPEN);
1637 	tq = tp->t_rawq;
1638 	tp->t_rawq.c_cc = 0;
1639 	tp->t_rawq.c_cf = tp->t_rawq.c_cl = 0;
1640 	while ((c = getc(&tq)) >= 0)
1641 		ttyinput_wlock(c, tp);
1642 	CLR(tp->t_state, TS_TYPEN);
1643 }
1644 
1645 /*
1646  * Process a read call on a tty device.
1647  */
1648 int
1649 ttread(struct tty *tp, struct uio *uio, int flag)
1650 {
1651 	struct clist	*qp;
1652 	u_char		*cc;
1653 	struct proc	*p;
1654 	int		c, first, error, has_stime, last_cc;
1655 	long		lflag, slp;
1656 	struct timeval	now, stime;
1657 
1658 	stime.tv_usec = 0;	/* XXX gcc */
1659 	stime.tv_sec = 0;	/* XXX gcc */
1660 
1661 	cc = tp->t_cc;
1662 	p = curproc;
1663 	error = 0;
1664 	has_stime = 0;
1665 	last_cc = 0;
1666 	slp = 0;
1667 
1668  loop:
1669 	mutex_spin_enter(&tty_lock);
1670 	lflag = tp->t_lflag;
1671 	/*
1672 	 * take pending input first
1673 	 */
1674 	if (ISSET(lflag, PENDIN))
1675 		ttypend(tp);
1676 
1677 	/*
1678 	 * Hang process if it's in the background.
1679 	 */
1680 	if (isbackground(p, tp)) {
1681 		if (sigismasked(curlwp, SIGTTIN) ||
1682 		    p->p_lflag & PL_PPWAIT || p->p_pgrp->pg_jobc == 0) {
1683 			mutex_spin_exit(&tty_lock);
1684 			return (EIO);
1685 		}
1686 		mutex_spin_exit(&tty_lock);
1687 
1688 		mutex_enter(proc_lock);
1689 		pgsignal(p->p_pgrp, SIGTTIN, 1);
1690 		mutex_exit(proc_lock);
1691 
1692 		mutex_spin_enter(&tty_lock);
1693 		error = ttysleep(tp, &lbolt, true, 0);
1694 		mutex_spin_exit(&tty_lock);
1695 		if (error)
1696 			return (error);
1697 		goto loop;
1698 	}
1699 
1700 	if (!ISSET(lflag, ICANON)) {
1701 		int m = cc[VMIN];
1702 		long t = cc[VTIME];
1703 
1704 		qp = &tp->t_rawq;
1705 		/*
1706 		 * Check each of the four combinations.
1707 		 * (m > 0 && t == 0) is the normal read case.
1708 		 * It should be fairly efficient, so we check that and its
1709 		 * companion case (m == 0 && t == 0) first.
1710 		 * For the other two cases, we compute the target sleep time
1711 		 * into slp.
1712 		 */
1713 		if (t == 0) {
1714 			if (qp->c_cc < m)
1715 				goto sleep;
1716 			goto read;
1717 		}
1718 		t *= hz;		/* time in deca-ticks */
1719 /*
1720  * Time difference in deca-ticks, split division to avoid numeric overflow.
1721  * Ok for hz < ~200kHz
1722  */
1723 #define	diff(t1, t2) (((t1).tv_sec - (t2).tv_sec) * 10 * hz + \
1724 			 ((t1).tv_usec - (t2).tv_usec) / 100 * hz / 1000)
1725 		if (m > 0) {
1726 			if (qp->c_cc <= 0)
1727 				goto sleep;
1728 			if (qp->c_cc >= m)
1729 				goto read;
1730 			if (!has_stime) {
1731 				/* first character, start timer */
1732 				has_stime = 1;
1733 				getmicrotime(&stime);
1734 				slp = t;
1735 			} else if (qp->c_cc > last_cc) {
1736 				/* got a character, restart timer */
1737 				getmicrotime(&stime);
1738 				slp = t;
1739 			} else {
1740 				/* nothing, check expiration */
1741 				getmicrotime(&now);
1742 				slp = t - diff(now, stime);
1743 			}
1744 		} else {	/* m == 0 */
1745 			if (qp->c_cc > 0)
1746 				goto read;
1747 			if (!has_stime) {
1748 				has_stime = 1;
1749 				getmicrotime(&stime);
1750 				slp = t;
1751 			} else {
1752 				getmicrotime(&now);
1753 				slp = t - diff(now, stime);
1754 			}
1755 		}
1756 		last_cc = qp->c_cc;
1757 #undef diff
1758 		if (slp > 0) {
1759 			/*
1760 			 * Convert deca-ticks back to ticks.
1761 			 * Rounding down may make us wake up just short
1762 			 * of the target, so we round up.
1763 			 * Maybe we should do 'slp/10 + 1' because the
1764 			 * first tick maybe almost immediate.
1765 			 * However it is more useful for a program that sets
1766 			 * VTIME=10 to wakeup every second not every 1.01
1767 			 * seconds (if hz=100).
1768 			 */
1769 			slp = (slp + 9)/ 10;
1770 			goto sleep;
1771 		}
1772 	} else if ((qp = &tp->t_canq)->c_cc <= 0) {
1773 		int	carrier;
1774 
1775  sleep:
1776 		/*
1777 		 * If there is no input, sleep on rawq
1778 		 * awaiting hardware receipt and notification.
1779 		 * If we have data, we don't need to check for carrier.
1780 		 */
1781 		carrier = CONNECTED(tp);
1782 		if (!carrier && ISSET(tp->t_state, TS_ISOPEN)) {
1783 			mutex_spin_exit(&tty_lock);
1784 			return (0);	/* EOF */
1785 		}
1786 		if (flag & IO_NDELAY) {
1787 			mutex_spin_exit(&tty_lock);
1788 			return (EWOULDBLOCK);
1789 		}
1790 		error = ttysleep(tp, &tp->t_rawcv, true, slp);
1791 		mutex_spin_exit(&tty_lock);
1792 		/* VMIN == 0: any quantity read satisfies */
1793 		if (cc[VMIN] == 0 && error == EWOULDBLOCK)
1794 			return (0);
1795 		if (error && error != EWOULDBLOCK)
1796 			return (error);
1797 		goto loop;
1798 	}
1799  read:
1800 	mutex_spin_exit(&tty_lock);
1801 
1802 	/*
1803 	 * Input present, check for input mapping and processing.
1804 	 */
1805 	first = 1;
1806 	while ((c = getc(qp)) >= 0) {
1807 		/*
1808 		 * delayed suspend (^Y)
1809 		 */
1810 		if (CCEQ(cc[VDSUSP], c) &&
1811 		    ISSET(lflag, IEXTEN|ISIG) == (IEXTEN|ISIG)) {
1812 			mutex_spin_enter(&tty_lock);
1813 			ttysig(tp, TTYSIG_PG1, SIGTSTP);
1814 			if (first) {
1815 				error = ttysleep(tp, &lbolt, true, 0);
1816 				mutex_spin_exit(&tty_lock);
1817 				if (error)
1818 					break;
1819 				goto loop;
1820 			} else
1821 				mutex_spin_exit(&tty_lock);
1822 			break;
1823 		}
1824 		/*
1825 		 * Interpret EOF only in canonical mode.
1826 		 */
1827 		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ICANON))
1828 			break;
1829 		/*
1830 		 * Give user character.
1831 		 */
1832  		error = ureadc(c, uio);
1833 		if (error)
1834 			break;
1835  		if (uio->uio_resid == 0)
1836 			break;
1837 		/*
1838 		 * In canonical mode check for a "break character"
1839 		 * marking the end of a "line of input".
1840 		 */
1841 		if (ISSET(lflag, ICANON) && TTBREAKC(c, lflag))
1842 			break;
1843 		first = 0;
1844 	}
1845 	/*
1846 	 * Look to unblock output now that (presumably)
1847 	 * the input queue has gone down.
1848 	 */
1849 	mutex_spin_enter(&tty_lock);
1850 	if (ISSET(tp->t_state, TS_TBLOCK) && tp->t_rawq.c_cc < TTYHOG / 5) {
1851 		if (ISSET(tp->t_iflag, IXOFF) &&
1852 		    cc[VSTART] != _POSIX_VDISABLE &&
1853 		    putc(cc[VSTART], &tp->t_outq) == 0) {
1854 			CLR(tp->t_state, TS_TBLOCK);
1855 			ttstart(tp);
1856 		}
1857 		/* Try to unblock remote output via hardware flow control. */
1858 		if (ISSET(tp->t_cflag, CHWFLOW) && tp->t_hwiflow &&
1859 		    (*tp->t_hwiflow)(tp, 0) != 0)
1860 			CLR(tp->t_state, TS_TBLOCK);
1861 	}
1862 	mutex_spin_exit(&tty_lock);
1863 
1864 	return (error);
1865 }
1866 
1867 /*
1868  * Check the output queue on tp for space for a kernel message (from uprintf
1869  * or tprintf).  Allow some space over the normal hiwater mark so we don't
1870  * lose messages due to normal flow control, but don't let the tty run amok.
1871  * Sleeps here are not interruptible, but we return prematurely if new signals
1872  * arrive.
1873  * Call with tty lock held.
1874  */
1875 static int
1876 ttycheckoutq_wlock(struct tty *tp, int wait)
1877 {
1878 	int	hiwat, error;
1879 
1880 	KASSERT(mutex_owned(&tty_lock));
1881 
1882 	hiwat = tp->t_hiwat;
1883 	if (tp->t_outq.c_cc > hiwat + 200)
1884 		while (tp->t_outq.c_cc > hiwat) {
1885 			ttstart(tp);
1886 			if (wait == 0)
1887 				return (0);
1888 			error = ttysleep(tp, &tp->t_outcv, true, hz);
1889 			if (error == EINTR)
1890 				wait = 0;
1891 		}
1892 
1893 	return (1);
1894 }
1895 
1896 int
1897 ttycheckoutq(struct tty *tp, int wait)
1898 {
1899 	int	r;
1900 
1901 	mutex_spin_enter(&tty_lock);
1902 	r = ttycheckoutq_wlock(tp, wait);
1903 	mutex_spin_exit(&tty_lock);
1904 
1905 	return (r);
1906 }
1907 
1908 /*
1909  * Process a write call on a tty device.
1910  */
1911 int
1912 ttwrite(struct tty *tp, struct uio *uio, int flag)
1913 {
1914 	u_char		*cp;
1915 	struct proc	*p;
1916 	int		cc, ce, i, hiwat, error;
1917 	size_t		cnt;
1918 	u_char		obuf[OBUFSIZ];
1919 
1920 	cp = NULL;
1921 	hiwat = tp->t_hiwat;
1922 	cnt = uio->uio_resid;
1923 	error = 0;
1924 	cc = 0;
1925  loop:
1926 	mutex_spin_enter(&tty_lock);
1927 	if (!CONNECTED(tp)) {
1928 		if (ISSET(tp->t_state, TS_ISOPEN)) {
1929 			mutex_spin_exit(&tty_lock);
1930 			return (EIO);
1931 		} else if (flag & IO_NDELAY) {
1932 			mutex_spin_exit(&tty_lock);
1933 			error = EWOULDBLOCK;
1934 			goto out;
1935 		} else {
1936 			/* Sleep awaiting carrier. */
1937 			error = ttysleep(tp, &tp->t_rawcv, true, 0);
1938 			mutex_spin_exit(&tty_lock);
1939 			if (error)
1940 				goto out;
1941 			goto loop;
1942 		}
1943 	}
1944 
1945 	/*
1946 	 * Hang the process if it's in the background.
1947 	 */
1948 	p = curproc;
1949 	if (isbackground(p, tp) &&
1950 	    ISSET(tp->t_lflag, TOSTOP) && (p->p_lflag & PL_PPWAIT) == 0 &&
1951 	    !sigismasked(curlwp, SIGTTOU)) {
1952 		if (p->p_pgrp->pg_jobc == 0) {
1953 			error = EIO;
1954 			mutex_spin_exit(&tty_lock);
1955 			goto out;
1956 		}
1957 		mutex_spin_exit(&tty_lock);
1958 
1959 		mutex_enter(proc_lock);
1960 		pgsignal(p->p_pgrp, SIGTTOU, 1);
1961 		mutex_exit(proc_lock);
1962 
1963 		mutex_spin_enter(&tty_lock);
1964 		error = ttysleep(tp, &lbolt, true, 0);
1965 		mutex_spin_exit(&tty_lock);
1966 		if (error)
1967 			goto out;
1968 		goto loop;
1969 	}
1970 	mutex_spin_exit(&tty_lock);
1971 
1972 	/*
1973 	 * Process the user's data in at most OBUFSIZ chunks.  Perform any
1974 	 * output translation.  Keep track of high water mark, sleep on
1975 	 * overflow awaiting device aid in acquiring new space.
1976 	 */
1977 	while (uio->uio_resid > 0 || cc > 0) {
1978 		if (ISSET(tp->t_lflag, FLUSHO)) {
1979 			uio->uio_resid = 0;
1980 			return (0);
1981 		}
1982 		if (tp->t_outq.c_cc > hiwat)
1983 			goto ovhiwat;
1984 		/*
1985 		 * Grab a hunk of data from the user, unless we have some
1986 		 * leftover from last time.
1987 		 */
1988 		if (cc == 0) {
1989 			cc = min(uio->uio_resid, OBUFSIZ);
1990 			cp = obuf;
1991 			error = uiomove(cp, cc, uio);
1992 			if (error) {
1993 				cc = 0;
1994 				goto out;
1995 			}
1996 		}
1997 		/*
1998 		 * If nothing fancy need be done, grab those characters we
1999 		 * can handle without any of ttyoutput's processing and
2000 		 * just transfer them to the output q.  For those chars
2001 		 * which require special processing (as indicated by the
2002 		 * bits in char_type), call ttyoutput.  After processing
2003 		 * a hunk of data, look for FLUSHO so ^O's will take effect
2004 		 * immediately.
2005 		 */
2006 		mutex_spin_enter(&tty_lock);
2007 		while (cc > 0) {
2008 			if (!ISSET(tp->t_oflag, OPOST))
2009 				ce = cc;
2010 			else {
2011 				ce = cc - scanc((u_int)cc, cp, char_type,
2012 				    CCLASSMASK);
2013 				/*
2014 				 * If ce is zero, then we're processing
2015 				 * a special character through ttyoutput.
2016 				 */
2017 				if (ce == 0) {
2018 					tp->t_rocount = 0;
2019 					if (ttyoutput(*cp, tp) >= 0) {
2020 						/* out of space */
2021 						mutex_spin_exit(&tty_lock);
2022 						goto overfull;
2023 					}
2024 					cp++;
2025 					cc--;
2026 					if (ISSET(tp->t_lflag, FLUSHO) ||
2027 					    tp->t_outq.c_cc > hiwat) {
2028 						mutex_spin_exit(&tty_lock);
2029 						goto ovhiwat;
2030 					}
2031 					continue;
2032 				}
2033 			}
2034 			/*
2035 			 * A bunch of normal characters have been found.
2036 			 * Transfer them en masse to the output queue and
2037 			 * continue processing at the top of the loop.
2038 			 * If there are any further characters in this
2039 			 * <= OBUFSIZ chunk, the first should be a character
2040 			 * requiring special handling by ttyoutput.
2041 			 */
2042 			tp->t_rocount = 0;
2043 			i = b_to_q(cp, ce, &tp->t_outq);
2044 			ce -= i;
2045 			tp->t_column += ce;
2046 			cp += ce, cc -= ce, tk_nout += ce;
2047 			tp->t_outcc += ce;
2048 			if (i > 0) {
2049 				/* out of space */
2050 				mutex_spin_exit(&tty_lock);
2051 				goto overfull;
2052 			}
2053 			if (ISSET(tp->t_lflag, FLUSHO) ||
2054 			    tp->t_outq.c_cc > hiwat)
2055 				break;
2056 		}
2057 		ttstart(tp);
2058 		mutex_spin_exit(&tty_lock);
2059 	}
2060 
2061  out:
2062 	/*
2063 	 * If cc is nonzero, we leave the uio structure inconsistent, as the
2064 	 * offset and iov pointers have moved forward, but it doesn't matter
2065 	 * (the call will either return short or restart with a new uio).
2066 	 */
2067 	uio->uio_resid += cc;
2068 	return (error);
2069 
2070  overfull:
2071 	/*
2072 	 * Since we are using ring buffers, if we can't insert any more into
2073 	 * the output queue, we can assume the ring is full and that someone
2074 	 * forgot to set the high water mark correctly.  We set it and then
2075 	 * proceed as normal.
2076 	 */
2077 	hiwat = tp->t_outq.c_cc - 1;
2078 
2079  ovhiwat:
2080 	mutex_spin_enter(&tty_lock);
2081 	ttstart(tp);
2082 	/*
2083 	 * This can only occur if FLUSHO is set in t_lflag,
2084 	 * or if ttstart/oproc is synchronous (or very fast).
2085 	 */
2086 	if (tp->t_outq.c_cc <= hiwat) {
2087 		mutex_spin_exit(&tty_lock);
2088 		goto loop;
2089 	}
2090 	if (flag & IO_NDELAY) {
2091 		mutex_spin_exit(&tty_lock);
2092 		error = EWOULDBLOCK;
2093 		goto out;
2094 	}
2095 	error = ttysleep(tp, &tp->t_outcv, true, 0);
2096 	mutex_spin_exit(&tty_lock);
2097 	if (error)
2098 		goto out;
2099 	goto loop;
2100 }
2101 
2102 /*
2103  * Try to pull more output from the producer.  Return non-zero if
2104  * there is output ready to be sent.
2105  */
2106 bool
2107 ttypull(struct tty *tp)
2108 {
2109 
2110 	/* XXXSMP not yet KASSERT(mutex_owned(&tty_lock)); */
2111 
2112 	if (tp->t_outq.c_cc <= tp->t_lowat) {
2113 		cv_broadcast(&tp->t_outcv);
2114 		selnotify(&tp->t_wsel, 0, NOTE_SUBMIT);
2115 	}
2116 	return tp->t_outq.c_cc != 0;
2117 }
2118 
2119 /*
2120  * Rubout one character from the rawq of tp
2121  * as cleanly as possible.
2122  * Called with tty lock held.
2123  */
2124 void
2125 ttyrub(int c, struct tty *tp)
2126 {
2127 	u_char	*cp;
2128 	int	savecol, tabc;
2129 
2130 	KASSERT(mutex_owned(&tty_lock));
2131 
2132 	if (!ISSET(tp->t_lflag, ECHO) || ISSET(tp->t_lflag, EXTPROC))
2133 		return;
2134 	CLR(tp->t_lflag, FLUSHO);
2135 	if (ISSET(tp->t_lflag, ECHOE)) {
2136 		if (tp->t_rocount == 0) {
2137 			/*
2138 			 * Screwed by ttwrite; retype
2139 			 */
2140 			ttyretype(tp);
2141 			return;
2142 		}
2143 		if (c == ('\t' | TTY_QUOTE) || c == ('\n' | TTY_QUOTE))
2144 			ttyrubo(tp, 2);
2145 		else {
2146 			CLR(c, ~TTY_CHARMASK);
2147 			switch (CCLASS(c)) {
2148 			case ORDINARY:
2149 				ttyrubo(tp, 1);
2150 				break;
2151 			case BACKSPACE:
2152 			case CONTROL:
2153 			case NEWLINE:
2154 			case RETURN:
2155 			case VTAB:
2156 				if (ISSET(tp->t_lflag, ECHOCTL))
2157 					ttyrubo(tp, 2);
2158 				break;
2159 			case TAB:
2160 				if (tp->t_rocount < tp->t_rawq.c_cc) {
2161 					ttyretype(tp);
2162 					return;
2163 				}
2164 				savecol = tp->t_column;
2165 				SET(tp->t_state, TS_CNTTB);
2166 				SET(tp->t_lflag, FLUSHO);
2167 				tp->t_column = tp->t_rocol;
2168 				for (cp = firstc(&tp->t_rawq, &tabc); cp;
2169 				    cp = nextc(&tp->t_rawq, cp, &tabc))
2170 					ttyecho(tabc, tp);
2171 				CLR(tp->t_lflag, FLUSHO);
2172 				CLR(tp->t_state, TS_CNTTB);
2173 
2174 				/* savecol will now be length of the tab. */
2175 				savecol -= tp->t_column;
2176 				tp->t_column += savecol;
2177 				if (savecol > 8)
2178 					savecol = 8;	/* overflow screw */
2179 				while (--savecol >= 0)
2180 					(void)ttyoutput('\b', tp);
2181 				break;
2182 			default:			/* XXX */
2183 				(void)printf("ttyrub: would panic c = %d, "
2184 				    "val = %d\n", c, CCLASS(c));
2185 			}
2186 		}
2187 	} else if (ISSET(tp->t_lflag, ECHOPRT)) {
2188 		if (!ISSET(tp->t_state, TS_ERASE)) {
2189 			SET(tp->t_state, TS_ERASE);
2190 			(void)ttyoutput('\\', tp);
2191 		}
2192 		ttyecho(c, tp);
2193 	} else
2194 		ttyecho(tp->t_cc[VERASE], tp);
2195 	--tp->t_rocount;
2196 }
2197 
2198 /*
2199  * Back over cnt characters, erasing them.
2200  * Called with tty lock held.
2201  */
2202 static void
2203 ttyrubo(struct tty *tp, int cnt)
2204 {
2205 
2206 	KASSERT(mutex_owned(&tty_lock));
2207 
2208 	while (cnt-- > 0) {
2209 		(void)ttyoutput('\b', tp);
2210 		(void)ttyoutput(' ', tp);
2211 		(void)ttyoutput('\b', tp);
2212 	}
2213 }
2214 
2215 /*
2216  * ttyretype --
2217  *	Reprint the rawq line.  Note, it is assumed that c_cc has already
2218  *	been checked.
2219  *
2220  * Called with tty lock held.
2221  */
2222 void
2223 ttyretype(struct tty *tp)
2224 {
2225 	u_char	*cp;
2226 	int	c;
2227 
2228 	KASSERT(mutex_owned(&tty_lock));
2229 
2230 	/* Echo the reprint character. */
2231 	if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
2232 		ttyecho(tp->t_cc[VREPRINT], tp);
2233 
2234 	(void)ttyoutput('\n', tp);
2235 
2236 	for (cp = firstc(&tp->t_canq, &c); cp; cp = nextc(&tp->t_canq, cp, &c))
2237 		ttyecho(c, tp);
2238 	for (cp = firstc(&tp->t_rawq, &c); cp; cp = nextc(&tp->t_rawq, cp, &c))
2239 		ttyecho(c, tp);
2240 	CLR(tp->t_state, TS_ERASE);
2241 
2242 	tp->t_rocount = tp->t_rawq.c_cc;
2243 	tp->t_rocol = 0;
2244 }
2245 
2246 /*
2247  * Echo a typed character to the terminal.
2248  * Called with tty lock held.
2249  */
2250 static void
2251 ttyecho(int c, struct tty *tp)
2252 {
2253 
2254 	KASSERT(mutex_owned(&tty_lock));
2255 
2256 	if (!ISSET(tp->t_state, TS_CNTTB))
2257 		CLR(tp->t_lflag, FLUSHO);
2258 	if ((!ISSET(tp->t_lflag, ECHO) &&
2259 	    (!ISSET(tp->t_lflag, ECHONL) || c != '\n')) ||
2260 	    ISSET(tp->t_lflag, EXTPROC))
2261 		return;
2262 	if (((ISSET(tp->t_lflag, ECHOCTL) &&
2263 	    (ISSET(c, TTY_CHARMASK) <= 037 && c != '\t' && c != '\n')) ||
2264 	    ISSET(c, TTY_CHARMASK) == 0177)) {
2265 		(void)ttyoutput('^', tp);
2266 		CLR(c, ~TTY_CHARMASK);
2267 		if (c == 0177)
2268 			c = '?';
2269 		else
2270 			c += 'A' - 1;
2271 	}
2272 	(void)ttyoutput(c, tp);
2273 }
2274 
2275 /*
2276  * Wake up any readers on a tty.
2277  * Called with tty lock held.
2278  */
2279 void
2280 ttwakeup(struct tty *tp)
2281 {
2282 
2283 	KASSERT(mutex_owned(&tty_lock));
2284 
2285 	selnotify(&tp->t_rsel, 0, NOTE_SUBMIT);
2286 	if (ISSET(tp->t_state, TS_ASYNC))
2287 		ttysig(tp, TTYSIG_PG2, SIGIO);
2288 	cv_broadcast(&tp->t_rawcv);
2289 }
2290 
2291 /*
2292  * Look up a code for a specified speed in a conversion table;
2293  * used by drivers to map software speed values to hardware parameters.
2294  */
2295 int
2296 ttspeedtab(int speed, const struct speedtab *table)
2297 {
2298 
2299 	for (; table->sp_speed != -1; table++)
2300 		if (table->sp_speed == speed)
2301 			return (table->sp_code);
2302 	return (-1);
2303 }
2304 
2305 /*
2306  * Set tty hi and low water marks.
2307  *
2308  * Try to arrange the dynamics so there's about one second
2309  * from hi to low water.
2310  */
2311 void
2312 ttsetwater(struct tty *tp)
2313 {
2314 	int	cps, x;
2315 
2316 	/* XXX not yet KASSERT(mutex_owned(&tty_lock)); */
2317 
2318 #define	CLAMP(x, h, l)	((x) > h ? h : ((x) < l) ? l : (x))
2319 
2320 	cps = tp->t_ospeed / 10;
2321 	tp->t_lowat = x = CLAMP(cps / 2, TTMAXLOWAT, TTMINLOWAT);
2322 	x += cps;
2323 	x = CLAMP(x, TTMAXHIWAT, TTMINHIWAT);
2324 	tp->t_hiwat = roundup(x, CBSIZE);
2325 #undef	CLAMP
2326 }
2327 
2328 /*
2329  * Prepare report on state of foreground process group.
2330  * Call with proc_lock held.
2331  */
2332 void
2333 ttygetinfo(struct tty *tp, int fromsig, char *buf, size_t bufsz)
2334 {
2335 	struct lwp	*l;
2336 	struct proc	*p, *pick = NULL;
2337 	struct timeval	utime, stime;
2338 	int		tmp;
2339 	fixpt_t		pctcpu = 0;
2340 	const char	*msg;
2341 	char		lmsg[100];
2342 	long		rss;
2343 
2344 	KASSERT(mutex_owned(proc_lock));
2345 
2346 	*buf = '\0';
2347 
2348 	if (tp->t_session == NULL)
2349 		msg = "not a controlling terminal\n";
2350 	else if (tp->t_pgrp == NULL)
2351 		msg = "no foreground process group\n";
2352 	else if ((p = LIST_FIRST(&tp->t_pgrp->pg_members)) == NULL)
2353 		msg = "empty foreground process group\n";
2354 	else {
2355 		/* Pick interesting process. */
2356 		for (; p != NULL; p = LIST_NEXT(p, p_pglist)) {
2357 			struct proc *oldpick;
2358 
2359 			if (pick == NULL) {
2360 				pick = p;
2361 				continue;
2362 			}
2363 			if (pick->p_lock < p->p_lock) {
2364 				mutex_enter(pick->p_lock);
2365 				mutex_enter(p->p_lock);
2366 			} else if (pick->p_lock > p->p_lock) {
2367 				mutex_enter(p->p_lock);
2368 				mutex_enter(pick->p_lock);
2369 			} else
2370 				mutex_enter(p->p_lock);
2371 			oldpick = pick;
2372 			if (proc_compare(pick, p))
2373 				pick = p;
2374 			mutex_exit(p->p_lock);
2375 			if (p->p_lock != oldpick->p_lock)
2376 				mutex_exit(oldpick->p_lock);
2377 		}
2378 		if (fromsig &&
2379 		    (SIGACTION_PS(pick->p_sigacts, SIGINFO).sa_flags &
2380 		    SA_NOKERNINFO))
2381 			return;
2382 		msg = NULL;
2383 	}
2384 
2385 	/* Print load average. */
2386 	tmp = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
2387 	snprintf(lmsg, sizeof(lmsg), "load: %d.%02d ", tmp / 100, tmp % 100);
2388 	strlcat(buf, lmsg, bufsz);
2389 
2390 	if (pick == NULL) {
2391 		strlcat(buf, msg, bufsz);
2392 		return;
2393 	}
2394 
2395 	snprintf(lmsg, sizeof(lmsg), " cmd: %s %d [", pick->p_comm,
2396 	    pick->p_pid);
2397 	strlcat(buf, lmsg, bufsz);
2398 
2399 	mutex_enter(pick->p_lock);
2400 	LIST_FOREACH(l, &pick->p_lwps, l_sibling) {
2401 		lwp_lock(l);
2402 		snprintf(lmsg, sizeof(lmsg), "%s%s",
2403 		    l->l_stat == LSONPROC ? "running" :
2404 		    l->l_stat == LSRUN ? "runnable" :
2405 		    l->l_wchan ? l->l_wmesg : "iowait",
2406 		    (LIST_NEXT(l, l_sibling) != NULL) ? " " : "] ");
2407 		lwp_unlock(l);
2408 		strlcat(buf, lmsg, bufsz);
2409 		pctcpu += l->l_pctcpu;
2410 	}
2411 	pctcpu += pick->p_pctcpu;
2412 	calcru(pick, &utime, &stime, NULL, NULL);
2413 	mutex_exit(pick->p_lock);
2414 
2415 	/* Round up and print user+system time, %CPU and RSS. */
2416 	utime.tv_usec += 5000;
2417 	if (utime.tv_usec >= 1000000) {
2418 		utime.tv_sec += 1;
2419 		utime.tv_usec -= 1000000;
2420 	}
2421 	stime.tv_usec += 5000;
2422 	if (stime.tv_usec >= 1000000) {
2423 		stime.tv_sec += 1;
2424 		stime.tv_usec -= 1000000;
2425 	}
2426 #define	pgtok(a)	(((u_long) ((a) * PAGE_SIZE) / 1024))
2427 	tmp = (pctcpu * 10000 + FSCALE / 2) >> FSHIFT;
2428 	if (pick->p_stat == SIDL || P_ZOMBIE(pick))
2429 		rss = 0;
2430 	else
2431 		rss = pgtok(vm_resident_count(pick->p_vmspace));
2432 
2433 	snprintf(lmsg, sizeof(lmsg), "%ld.%02ldu %ld.%02lds %d%% %ldk",
2434 	    (long)utime.tv_sec, (long)utime.tv_usec / 10000,
2435 	    (long)stime.tv_sec, (long)stime.tv_usec / 10000,
2436 	    tmp / 100, rss);
2437 	strlcat(buf, lmsg, bufsz);
2438 }
2439 
2440 /*
2441  * Print report on state of foreground process group.
2442  * Call with tty_lock held.
2443  */
2444 void
2445 ttyputinfo(struct tty *tp, char *buf)
2446 {
2447 
2448 	KASSERT(mutex_owned(&tty_lock));
2449 
2450 	if (ttycheckoutq_wlock(tp, 0) == 0)
2451 		return;
2452 	ttyprintf_nolock(tp, "%s\n", buf);
2453 	tp->t_rocount = 0;	/* so pending input will be retyped if BS */
2454 }
2455 
2456 /*
2457  * Returns 1 if p2 is "better" than p1
2458  *
2459  * The algorithm for picking the "interesting" process is thus:
2460  *
2461  *	1) Only foreground processes are eligible - implied.
2462  *	2) Runnable processes are favored over anything else.  The runner
2463  *	   with the highest CPU utilization is picked (l_pctcpu).  Ties are
2464  *	   broken by picking the highest pid.
2465  *	3) The sleeper with the shortest sleep time is next.  With ties,
2466  *	   we pick out just "short-term" sleepers (P_SINTR == 0).
2467  *	4) Further ties are broken by picking the highest pid.
2468  */
2469 #define	ISRUN(p)	((p)->p_nrlwps > 0)
2470 #define	TESTAB(a, b)	((a)<<1 | (b))
2471 #define	ONLYA	2
2472 #define	ONLYB	1
2473 #define	BOTH	3
2474 
2475 static int
2476 proc_compare(struct proc *p1, struct proc *p2)
2477 {
2478 	lwp_t *l1, *l2;
2479 
2480 	KASSERT(mutex_owned(p1->p_lock));
2481 	KASSERT(mutex_owned(p2->p_lock));
2482 
2483 	if ((l1 = LIST_FIRST(&p1->p_lwps)) == NULL)
2484 		return (1);
2485 	if ((l2 = LIST_FIRST(&p2->p_lwps)) == NULL)
2486 		return (0);
2487 	/*
2488 	 * see if at least one of them is runnable
2489 	 */
2490 	switch (TESTAB(ISRUN(p1), ISRUN(p2))) {
2491 	case ONLYA:
2492 		return (0);
2493 	case ONLYB:
2494 		return (1);
2495 	case BOTH:
2496 		/*
2497 		 * tie - favor one with highest recent CPU utilization
2498 		 */
2499 		if (l2->l_pctcpu > l1->l_pctcpu)
2500 			return (1);
2501 		return (p2->p_pid > p1->p_pid);	/* tie - return highest pid */
2502 	}
2503 	/*
2504  	 * weed out zombies
2505 	 */
2506 	switch (TESTAB(P_ZOMBIE(p1), P_ZOMBIE(p2))) {
2507 	case ONLYA:
2508 		return (1);
2509 	case ONLYB:
2510 		return (0);
2511 	case BOTH:
2512 		return (p2->p_pid > p1->p_pid);	/* tie - return highest pid */
2513 	}
2514 	/*
2515 	 * pick the one with the smallest sleep time
2516 	 */
2517 	if (l2->l_slptime > l2->l_slptime)
2518 		return (0);
2519 	if (l2->l_slptime > l2->l_slptime)
2520 		return (1);
2521 	/*
2522 	 * favor one sleeping in a non-interruptible sleep
2523 	 */
2524 	if (l2->l_flag & LW_SINTR && (l2->l_flag & LW_SINTR) == 0)
2525 		return (1);
2526 	if (l2->l_flag & LW_SINTR && (l2->l_flag & LW_SINTR) == 0)
2527 		return (0);
2528 	return (p2->p_pid > p1->p_pid);		/* tie - return highest pid */
2529 }
2530 
2531 /*
2532  * Output char to tty; console putchar style.
2533  * Can be called with tty lock held through kprintf() machinery..
2534  */
2535 int
2536 tputchar(int c, int flags, struct tty *tp)
2537 {
2538 	int r = 0;
2539 
2540 	if ((flags & NOLOCK) == 0)
2541 		mutex_spin_enter(&tty_lock);
2542 	if (!CONNECTED(tp)) {
2543 		r = -1;
2544 		goto out;
2545 	}
2546 	if (c == '\n')
2547 		(void)ttyoutput('\r', tp);
2548 	(void)ttyoutput(c, tp);
2549 	ttstart(tp);
2550 out:
2551 	if ((flags & NOLOCK) == 0)
2552 		mutex_spin_exit(&tty_lock);
2553 	return (r);
2554 }
2555 
2556 /*
2557  * Sleep on chan, returning ERESTART if tty changed while we napped and
2558  * returning any errors (e.g. EINTR/ETIMEDOUT) reported by tsleep.  If
2559  * the tty is revoked, restarting a pending call will redo validation done
2560  * at the start of the call.
2561  *
2562  * Must be called with the tty lock held.
2563  */
2564 int
2565 ttysleep(struct tty *tp, kcondvar_t *cv, bool catch, int timo)
2566 {
2567 	int	error;
2568 	short	gen;
2569 
2570 	KASSERT(mutex_owned(&tty_lock));
2571 
2572 	gen = tp->t_gen;
2573 	if (catch)
2574 		error = cv_timedwait_sig(cv, &tty_lock, timo);
2575 	else
2576 		error = cv_timedwait(cv, &tty_lock, timo);
2577 	if (error != 0)
2578 		return (error);
2579 	return (tp->t_gen == gen ? 0 : ERESTART);
2580 }
2581 
2582 /*
2583  * Attach a tty to the tty list.
2584  *
2585  * This should be called ONLY once per real tty (including pty's).
2586  * eg, on the sparc, the keyboard and mouse have struct tty's that are
2587  * distinctly NOT usable as tty's, and thus should not be attached to
2588  * the ttylist.  This is why this call is not done from ttymalloc().
2589  *
2590  * Device drivers should attach tty's at a similar time that they are
2591  * ttymalloc()'ed, or, for the case of statically allocated struct tty's
2592  * either in the attach or (first) open routine.
2593  */
2594 void
2595 tty_attach(struct tty *tp)
2596 {
2597 
2598 	mutex_spin_enter(&tty_lock);
2599 	TAILQ_INSERT_TAIL(&ttylist, tp, tty_link);
2600 	++tty_count;
2601 	mutex_spin_exit(&tty_lock);
2602 }
2603 
2604 /*
2605  * Remove a tty from the tty list.
2606  */
2607 void
2608 tty_detach(struct tty *tp)
2609 {
2610 
2611 	mutex_spin_enter(&tty_lock);
2612 	--tty_count;
2613 #ifdef DIAGNOSTIC
2614 	if (tty_count < 0)
2615 		panic("tty_detach: tty_count < 0");
2616 #endif
2617 	TAILQ_REMOVE(&ttylist, tp, tty_link);
2618 	mutex_spin_exit(&tty_lock);
2619 }
2620 
2621 /*
2622  * Allocate a tty structure and its associated buffers.
2623  */
2624 struct tty *
2625 ttymalloc(void)
2626 {
2627 	struct tty	*tp;
2628 	int i;
2629 
2630 	tp = kmem_zalloc(sizeof(*tp), KM_SLEEP);
2631 	callout_init(&tp->t_rstrt_ch, 0);
2632 	callout_setfunc(&tp->t_rstrt_ch, ttrstrt, tp);
2633 	/* XXX: default to 1024 chars for now */
2634 	clalloc(&tp->t_rawq, 1024, 1);
2635 	cv_init(&tp->t_rawcv, "ttyraw");
2636 	cv_init(&tp->t_rawcvf, "ttyrawf");
2637 	clalloc(&tp->t_canq, 1024, 1);
2638 	cv_init(&tp->t_cancv, "ttycan");
2639 	cv_init(&tp->t_cancvf, "ttycanf");
2640 	/* output queue doesn't need quoting */
2641 	clalloc(&tp->t_outq, 1024, 0);
2642 	cv_init(&tp->t_outcv, "ttyout");
2643 	cv_init(&tp->t_outcvf, "ttyoutf");
2644 	/* Set default line discipline. */
2645 	tp->t_linesw = ttyldisc_default();
2646 	selinit(&tp->t_rsel);
2647 	selinit(&tp->t_wsel);
2648 	for (i = 0; i < TTYSIG_COUNT; i++)
2649 		sigemptyset(&tp->t_sigs[i]);
2650 	return (tp);
2651 }
2652 
2653 /*
2654  * Free a tty structure and its buffers.
2655  *
2656  * Be sure to call tty_detach() for any tty that has been
2657  * tty_attach()ed.
2658  */
2659 void
2660 ttyfree(struct tty *tp)
2661 {
2662 	int i;
2663 
2664 	mutex_enter(proc_lock);
2665 	mutex_enter(&tty_lock);
2666 	for (i = 0; i < TTYSIG_COUNT; i++)
2667 		sigemptyset(&tp->t_sigs[i]);
2668 	if (tp->t_sigcount != 0)
2669 		TAILQ_REMOVE(&tty_sigqueue, tp, t_sigqueue);
2670 	mutex_exit(&tty_lock);
2671 	mutex_exit(proc_lock);
2672 
2673 	callout_halt(&tp->t_rstrt_ch, NULL);
2674 	callout_destroy(&tp->t_rstrt_ch);
2675 	ttyldisc_release(tp->t_linesw);
2676 	clfree(&tp->t_rawq);
2677 	clfree(&tp->t_canq);
2678 	clfree(&tp->t_outq);
2679 	cv_destroy(&tp->t_rawcv);
2680 	cv_destroy(&tp->t_rawcvf);
2681 	cv_destroy(&tp->t_cancv);
2682 	cv_destroy(&tp->t_cancvf);
2683 	cv_destroy(&tp->t_outcv);
2684 	cv_destroy(&tp->t_outcvf);
2685 	seldestroy(&tp->t_rsel);
2686 	seldestroy(&tp->t_wsel);
2687 	kmem_free(tp, sizeof(*tp));
2688 }
2689 
2690 /*
2691  * ttyprintf_nolock: send a message to a specific tty, without locking.
2692  *
2693  * => should be used only by tty driver or anything that knows the
2694  *    underlying tty will not be revoked(2)'d away.  [otherwise,
2695  *    use tprintf]
2696  */
2697 static void
2698 ttyprintf_nolock(struct tty *tp, const char *fmt, ...)
2699 {
2700 	va_list ap;
2701 
2702 	/* No mutex needed; going to process TTY. */
2703 	va_start(ap, fmt);
2704 	kprintf(fmt, TOTTY|NOLOCK, tp, NULL, ap);
2705 	va_end(ap);
2706 }
2707 
2708 /*
2709  * Initialize the tty subsystem.
2710  */
2711 void
2712 tty_init(void)
2713 {
2714 
2715 	mutex_init(&tty_lock, MUTEX_DEFAULT, IPL_VM);
2716 	tty_sigsih = softint_establish(SOFTINT_CLOCK, ttysigintr, NULL);
2717 	KASSERT(tty_sigsih != NULL);
2718 }
2719 
2720 /*
2721  * Send a signal from a tty to its process group or session leader.
2722  * Handoff to the target is deferred to a soft interrupt.
2723  */
2724 void
2725 ttysig(struct tty *tp, enum ttysigtype st, int sig)
2726 {
2727 	sigset_t *sp;
2728 
2729 	/* XXXSMP not yet KASSERT(mutex_owned(&tty_lock)); */
2730 
2731 	sp = &tp->t_sigs[st];
2732 	if (sigismember(sp, sig))
2733 		return;
2734 	sigaddset(sp, sig);
2735 	if (tp->t_sigcount++ == 0)
2736 		TAILQ_INSERT_TAIL(&tty_sigqueue, tp, t_sigqueue);
2737 	softint_schedule(tty_sigsih);
2738 }
2739 
2740 /*
2741  * Deliver deferred signals from ttys.  Note that the process groups
2742  * and sessions associated with the ttys may have changed from when
2743  * the signal was originally sent, but in practice it should not matter.
2744  * For signals produced as a result of a syscall, the soft interrupt
2745  * will fire before the syscall returns to the user.
2746  */
2747 static void
2748 ttysigintr(void *cookie)
2749 {
2750 	struct tty *tp;
2751 	enum ttysigtype st;
2752 	struct pgrp *pgrp;
2753 	struct session *sess;
2754 	int sig, lflag;
2755 	char infobuf[200];
2756 
2757 	mutex_enter(proc_lock);
2758 	mutex_spin_enter(&tty_lock);
2759 	while ((tp = TAILQ_FIRST(&tty_sigqueue)) != NULL) {
2760 		KASSERT(tp->t_sigcount > 0);
2761 		for (st = 0; st < TTYSIG_COUNT; st++) {
2762 			if ((sig = firstsig(&tp->t_sigs[st])) != 0)
2763 				break;
2764 		}
2765 		KASSERT(st < TTYSIG_COUNT);
2766 		sigdelset(&tp->t_sigs[st], sig);
2767 		if (--tp->t_sigcount == 0)
2768 			TAILQ_REMOVE(&tty_sigqueue, tp, t_sigqueue);
2769 		pgrp = tp->t_pgrp;
2770 		sess = tp->t_session;
2771 		lflag = tp->t_lflag;
2772 		if  (sig == SIGINFO) {
2773 			if (ISSET(tp->t_state, TS_SIGINFO)) {
2774 				/* Via ioctl: ignore tty option. */
2775 				tp->t_state &= ~TS_SIGINFO;
2776 				lflag |= ISIG;
2777 			}
2778 			if (!ISSET(lflag, NOKERNINFO)) {
2779 				mutex_spin_exit(&tty_lock);
2780 				ttygetinfo(tp, 1, infobuf, sizeof(infobuf));
2781 				mutex_spin_enter(&tty_lock);
2782 				ttyputinfo(tp, infobuf);
2783 			}
2784 			if (!ISSET(lflag, ISIG))
2785 				continue;
2786 		}
2787 		mutex_spin_exit(&tty_lock);
2788 		KASSERT(sig != 0);
2789 		switch (st) {
2790 		case TTYSIG_PG1:
2791 			if (pgrp != NULL)
2792 				pgsignal(pgrp, sig, 1);
2793 			break;
2794 		case TTYSIG_PG2:
2795 			if (pgrp != NULL)
2796 				pgsignal(pgrp, sig, sess != NULL);
2797 			break;
2798 		case TTYSIG_LEADER:
2799 			if (sess != NULL && sess->s_leader != NULL)
2800 				psignal(sess->s_leader, sig);
2801 			break;
2802 		default:
2803 			/* NOTREACHED */
2804 			break;
2805 		}
2806 		mutex_spin_enter(&tty_lock);
2807 	}
2808 	mutex_spin_exit(&tty_lock);
2809 	mutex_exit(proc_lock);
2810 }
2811