xref: /netbsd-src/sys/kern/tty.c (revision 53d1339bf7f9c7367b35a9e1ebe693f9b047a47b)
1 /*	$NetBSD: tty.c,v 1.295 2020/12/11 03:00:09 thorpej Exp $	*/
2 
3 /*-
4  * Copyright (c) 2008, 2020 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 1.295 2020/12/11 03:00:09 thorpej Exp $");
67 
68 #ifdef _KERNEL_OPT
69 #include "opt_compat_netbsd.h"
70 #endif
71 
72 #define TTY_ALLOW_PRIVATE
73 
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/ioctl.h>
77 #include <sys/proc.h>
78 #define	TTYDEFCHARS
79 #include <sys/tty.h>
80 #undef	TTYDEFCHARS
81 #include <sys/file.h>
82 #include <sys/conf.h>
83 #include <sys/cpu.h>
84 #include <sys/dkstat.h>
85 #include <sys/uio.h>
86 #include <sys/kernel.h>
87 #include <sys/vnode.h>
88 #include <sys/syslog.h>
89 #include <sys/kmem.h>
90 #include <sys/signalvar.h>
91 #include <sys/resourcevar.h>
92 #include <sys/poll.h>
93 #include <sys/kprintf.h>
94 #include <sys/namei.h>
95 #include <sys/sysctl.h>
96 #include <sys/kauth.h>
97 #include <sys/intr.h>
98 #include <sys/ioctl_compat.h>
99 #include <sys/module.h>
100 #include <sys/bitops.h>
101 #include <sys/compat_stub.h>
102 
103 #ifdef COMPAT_60
104 #include <compat/sys/ttycom.h>
105 #endif /* COMPAT_60 */
106 
107 static int	ttnread(struct tty *);
108 static void	ttyblock(struct tty *);
109 static void	ttyecho(int, struct tty *);
110 static void	ttyrubo(struct tty *, int);
111 static void	ttyprintf_nolock(struct tty *, const char *fmt, ...)
112     __printflike(2, 3);
113 static int	proc_compare_wrapper(struct proc *, struct proc *);
114 static void	ttysigintr(void *);
115 
116 /* Symbolic sleep message strings. */
117 const char	ttclos[] = "ttycls";
118 const char	ttopen[] = "ttyopn";
119 const char	ttybg[] = "ttybg";
120 const char	ttyin[] = "ttyin";
121 const char	ttyout[] = "ttyout";
122 
123 /*
124  * Used to determine whether we still have a connection.  This is true in
125  * one of 3 cases:
126  * 1) We have carrier.
127  * 2) It's a locally attached terminal, and we are therefore ignoring carrier.
128  * 3) We're using a flow control mechanism that overloads the carrier signal.
129  */
130 #define	CONNECTED(tp)	(ISSET(tp->t_state, TS_CARR_ON) ||	\
131 			 ISSET(tp->t_cflag, CLOCAL | MDMBUF))
132 
133 /*
134  * Table with character classes and parity. The 8th bit indicates parity,
135  * the 7th bit indicates the character is an alphameric or underscore (for
136  * ALTWERASE), and the low 6 bits indicate delay type.  If the low 6 bits
137  * are 0 then the character needs no special processing on output; classes
138  * other than 0 might be translated or (not currently) require delays.
139  */
140 #define	E	0x00	/* Even parity. */
141 #define	O	0x80	/* Odd parity. */
142 #define	PARITY(c)	(char_type[c] & O)
143 
144 #define	ALPHA	0x40	/* Alpha or underscore. */
145 #define	ISALPHA(c)	(char_type[(c) & TTY_CHARMASK] & ALPHA)
146 
147 #define	CCLASSMASK	0x3f
148 #define	CCLASS(c)	(char_type[c] & CCLASSMASK)
149 
150 #define	BS	BACKSPACE
151 #define	CC	CONTROL
152 #define	CR	RETURN
153 #define	NA	ORDINARY | ALPHA
154 #define	NL	NEWLINE
155 #define	NO	ORDINARY
156 #define	TB	TAB
157 #define	VT	VTAB
158 
159 unsigned char const char_type[] = {
160 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* nul - bel */
161 	O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC,	/* bs - si */
162 	O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC,	/* dle - etb */
163 	E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC,	/* can - us */
164 	O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO,	/* sp - ' */
165 	E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO,	/* ( - / */
166 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* 0 - 7 */
167 	O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO,	/* 8 - ? */
168 	O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* @ - G */
169 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* H - O */
170 	E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* P - W */
171 	O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA,	/* X - _ */
172 	E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA,	/* ` - g */
173 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* h - o */
174 	O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA,	/* p - w */
175 	E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC,	/* x - del */
176 	/*
177 	 * Meta chars; should be settable per character set;
178 	 * for now, treat them all as normal characters.
179 	 */
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 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
185 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
186 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
187 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
188 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
189 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
190 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
191 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
192 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
193 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
194 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
195 	NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
196 };
197 #undef	BS
198 #undef	CC
199 #undef	CR
200 #undef	NA
201 #undef	NL
202 #undef	NO
203 #undef	TB
204 #undef	VT
205 
206 static struct ttylist_head tty_sigqueue = TAILQ_HEAD_INITIALIZER(tty_sigqueue);
207 static void *tty_sigsih;
208 
209 struct ttylist_head ttylist = TAILQ_HEAD_INITIALIZER(ttylist);
210 int tty_count;
211 kmutex_t tty_lock;
212 
213 struct ptm_pty *ptm = NULL;
214 
215 uint64_t tk_cancc;
216 uint64_t tk_nin;
217 uint64_t tk_nout;
218 uint64_t tk_rawcc;
219 
220 static kauth_listener_t tty_listener;
221 
222 #define	TTY_MINQSIZE	0x00400
223 #define	TTY_MAXQSIZE	0x10000
224 int tty_qsize = TTY_MINQSIZE;
225 
226 static int
227 tty_get_qsize(int *qsize, int newsize)
228 {
229 	if (newsize <= 0)
230 		return EINVAL;
231 
232 	newsize = 1 << ilog2(newsize);	/* Make it a power of two */
233 
234 	if (newsize < TTY_MINQSIZE || newsize > TTY_MAXQSIZE)
235 		return EINVAL;
236 
237 	*qsize = newsize;
238 	return 0;
239 }
240 
241 static int
242 tty_set_qsize(struct tty *tp, int newsize)
243 {
244 	struct clist rawq, canq, outq;
245 	struct clist orawq, ocanq, ooutq;
246 
247 	clalloc(&rawq, newsize, 1);
248 	clalloc(&canq, newsize, 1);
249 	clalloc(&outq, newsize, 0);
250 
251 	mutex_spin_enter(&tty_lock);
252 
253 	if (tp->t_outq.c_cc != 0) {
254 		mutex_spin_exit(&tty_lock);
255 		clfree(&rawq);
256 		clfree(&canq);
257 		clfree(&outq);
258 		return EBUSY;
259 	}
260 
261 	orawq = tp->t_rawq;
262 	ocanq = tp->t_canq;
263 	ooutq = tp->t_outq;
264 
265 	tp->t_qsize = newsize;
266 	tp->t_rawq = rawq;
267 	tp->t_canq = canq;
268 	tp->t_outq = outq;
269 
270 	ttsetwater(tp);
271 
272 	mutex_spin_exit(&tty_lock);
273 
274 	clfree(&orawq);
275 	clfree(&ocanq);
276 	clfree(&ooutq);
277 
278 	return 0;
279 }
280 
281 static int
282 sysctl_kern_tty_qsize(SYSCTLFN_ARGS)
283 {
284 	int newsize;
285 	int error;
286 	struct sysctlnode node;
287 	node = *rnode;
288 	node.sysctl_data = &newsize;
289 
290 	newsize = tty_qsize;
291 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
292 	if (error || newp == NULL)
293 		return error;
294 
295 
296 	return tty_get_qsize(&tty_qsize, newsize);
297 }
298 
299 static void
300 sysctl_kern_tty_setup(void)
301 {
302 	const struct sysctlnode *rnode, *cnode;
303 
304 	sysctl_createv(NULL, 0, NULL, NULL,
305 		       CTLFLAG_PERMANENT,
306 		       CTLTYPE_NODE, "tkstat",
307 		       SYSCTL_DESCR("Number of characters sent and received "
308 				    "on ttys"),
309 		       NULL, 0, NULL, 0,
310 		       CTL_KERN, KERN_TKSTAT, CTL_EOL);
311 
312 	sysctl_createv(NULL, 0, NULL, NULL,
313 		       CTLFLAG_PERMANENT,
314 		       CTLTYPE_QUAD, "nin",
315 		       SYSCTL_DESCR("Total number of tty input characters"),
316 		       NULL, 0, &tk_nin, 0,
317 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_NIN, CTL_EOL);
318 	sysctl_createv(NULL, 0, NULL, NULL,
319 		       CTLFLAG_PERMANENT,
320 		       CTLTYPE_QUAD, "nout",
321 		       SYSCTL_DESCR("Total number of tty output characters"),
322 		       NULL, 0, &tk_nout, 0,
323 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_NOUT, CTL_EOL);
324 	sysctl_createv(NULL, 0, NULL, NULL,
325 		       CTLFLAG_PERMANENT,
326 		       CTLTYPE_QUAD, "cancc",
327 		       SYSCTL_DESCR("Number of canonical tty input characters"),
328 		       NULL, 0, &tk_cancc, 0,
329 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_CANCC, CTL_EOL);
330 	sysctl_createv(NULL, 0, NULL, NULL,
331 		       CTLFLAG_PERMANENT,
332 		       CTLTYPE_QUAD, "rawcc",
333 		       SYSCTL_DESCR("Number of raw tty input characters"),
334 		       NULL, 0, &tk_rawcc, 0,
335 		       CTL_KERN, KERN_TKSTAT, KERN_TKSTAT_RAWCC, CTL_EOL);
336 
337 	sysctl_createv(NULL, 0, NULL, &rnode,
338 		       CTLFLAG_PERMANENT,
339 		       CTLTYPE_NODE, "tty", NULL,
340 		       NULL, 0, NULL, 0,
341 		       CTL_KERN, CTL_CREATE, CTL_EOL);
342 	sysctl_createv(NULL, 0, &rnode, &cnode,
343 		       CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
344 		       CTLTYPE_INT, "qsize",
345 		       SYSCTL_DESCR("TTY input and output queue size"),
346 		       sysctl_kern_tty_qsize, 0, &tty_qsize, 0,
347 		       CTL_CREATE, CTL_EOL);
348 }
349 
350 int
351 ttyopen(struct tty *tp, int dialout, int nonblock)
352 {
353 	int	error;
354 
355 	error = 0;
356 
357 	mutex_spin_enter(&tty_lock);
358 
359 	if (dialout) {
360 		/*
361 		 * If the device is already open for non-dialout, fail.
362 		 * Otherwise, set TS_DIALOUT to block any pending non-dialout
363 		 * opens.
364 		 */
365 		if (ISSET(tp->t_state, TS_ISOPEN) &&
366 		    !ISSET(tp->t_state, TS_DIALOUT)) {
367 			error = EBUSY;
368 			goto out;
369 		}
370 		SET(tp->t_state, TS_DIALOUT);
371 	} else {
372 		if (!nonblock) {
373 			/*
374 			 * Wait for carrier.  Also wait for any dialout
375 			 * processes to close the tty first.
376 			 */
377 			while (ISSET(tp->t_state, TS_DIALOUT) ||
378 			       !CONNECTED(tp)) {
379 				tp->t_wopen++;
380 				error = ttysleep(tp, &tp->t_rawcv, true, 0);
381 				tp->t_wopen--;
382 				if (error)
383 					goto out;
384 			}
385 		} else {
386 			/*
387 			 * Don't allow a non-blocking non-dialout open if the
388 			 * device is already open for dialout.
389 			 */
390 			if (ISSET(tp->t_state, TS_DIALOUT)) {
391 				error = EBUSY;
392 				goto out;
393 			}
394 		}
395 	}
396 
397 out:
398 	mutex_spin_exit(&tty_lock);
399 	return (error);
400 }
401 
402 /*
403  * Initial open of tty, or (re)entry to standard tty line discipline.
404  */
405 int
406 ttylopen(dev_t device, struct tty *tp)
407 {
408 
409 	mutex_spin_enter(&tty_lock);
410 	tp->t_dev = device;
411 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
412 		SET(tp->t_state, TS_ISOPEN);
413 		memset(&tp->t_winsize, 0, sizeof(tp->t_winsize));
414 		tp->t_flags = 0;
415 	}
416 	mutex_spin_exit(&tty_lock);
417 	if (tp->t_qsize != tty_qsize)
418 		tty_set_qsize(tp, tty_qsize);
419 	return (0);
420 }
421 
422 /*
423  * Handle close() on a tty line: flush and set to initial state,
424  * bumping generation number so that pending read/write calls
425  * can detect recycling of the tty.
426  */
427 int
428 ttyclose(struct tty *tp)
429 {
430 	extern struct tty *constty;	/* Temporary virtual console. */
431 	struct session *sess;
432 
433 	mutex_spin_enter(&tty_lock);
434 
435 	if (constty == tp)
436 		constty = NULL;
437 
438 	ttyflush(tp, FREAD | FWRITE);
439 
440 	tp->t_gen++;
441 	tp->t_pgrp = NULL;
442 	tp->t_state = 0;
443 	sess = tp->t_session;
444 	tp->t_session = NULL;
445 
446 	mutex_spin_exit(&tty_lock);
447 
448 	if (sess != NULL) {
449 		mutex_enter(&proc_lock);
450 		/* Releases proc_lock. */
451 		proc_sessrele(sess);
452 	}
453 	return (0);
454 }
455 
456 #define	FLUSHQ(q) {							\
457 	if ((q)->c_cc)							\
458 		ndflush(q, (q)->c_cc);					\
459 }
460 
461 /*
462  * This macro is used in canonical mode input processing, where a read
463  * request shall not return unless a 'line delimiter' ('\n') or 'break'
464  * (EOF, EOL, EOL2) character (or a signal) has been received. As EOL2
465  * is an extension to the POSIX.1 defined set of special characters,
466  * recognize it only if IEXTEN is set in the set of local flags.
467  */
468 #define	TTBREAKC(c, lflg)						\
469 	((c) == '\n' || (((c) == cc[VEOF] || (c) == cc[VEOL] ||		\
470 	((c) == cc[VEOL2] && ISSET(lflg, IEXTEN))) && (c) != _POSIX_VDISABLE))
471 
472 
473 
474 /*
475  * ttyinput() helper.
476  * Call with the tty lock held.
477  */
478 /* XXX static */ int
479 ttyinput_wlock(int c, struct tty *tp)
480 {
481 	int	iflag, lflag, i, error;
482 	u_char	*cc;
483 
484 	KASSERT(mutex_owned(&tty_lock));
485 
486 	/*
487 	 * If input is pending take it first.
488 	 */
489 	lflag = tp->t_lflag;
490 	if (ISSET(lflag, PENDIN))
491 		ttypend(tp);
492 	/*
493 	 * Gather stats.
494 	 */
495 	if (ISSET(lflag, ICANON)) {
496 		++tk_cancc;
497 		++tp->t_cancc;
498 	} else {
499 		++tk_rawcc;
500 		++tp->t_rawcc;
501 	}
502 	++tk_nin;
503 
504 	cc = tp->t_cc;
505 
506 	/*
507 	 * Handle exceptional conditions (break, parity, framing).
508 	 */
509 	iflag = tp->t_iflag;
510 	if ((error = (ISSET(c, TTY_ERRORMASK))) != 0) {
511 		CLR(c, TTY_ERRORMASK);
512 		if (ISSET(error, TTY_FE) && c == 0) {		/* Break. */
513 			if (ISSET(iflag, IGNBRK))
514 				return (0);
515 			else if (ISSET(iflag, BRKINT)) {
516 				ttyflush(tp, FREAD | FWRITE);
517 				ttysig(tp, TTYSIG_PG1, SIGINT);
518 				return (0);
519 			} else if (ISSET(iflag, PARMRK))
520 				goto parmrk;
521 		} else if ((ISSET(error, TTY_PE) && ISSET(iflag, INPCK)) ||
522 		    ISSET(error, TTY_FE)) {
523 			if (ISSET(iflag, IGNPAR))
524 				return (0);
525 			else if (ISSET(iflag, PARMRK)) {
526  parmrk:			(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
527 				(void)putc(0    | TTY_QUOTE, &tp->t_rawq);
528 				(void)putc(c    | TTY_QUOTE, &tp->t_rawq);
529 				return (0);
530 			} else
531 				c = 0;
532 		}
533 	} else if (c == 0377 &&
534 	    ISSET(iflag, ISTRIP|IGNPAR|INPCK|PARMRK) == (INPCK|PARMRK)) {
535 		/* "Escape" a valid character of '\377'. */
536 		(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
537 		(void)putc(0377 | TTY_QUOTE, &tp->t_rawq);
538 		goto endcase;
539 	}
540 
541 	/*
542 	 * In tandem mode, check high water mark.
543 	 */
544 	if (ISSET(iflag, IXOFF) || ISSET(tp->t_cflag, CHWFLOW))
545 		ttyblock(tp);
546 	if (!ISSET(tp->t_state, TS_TYPEN) && ISSET(iflag, ISTRIP))
547 		CLR(c, 0x80);
548 	if (!ISSET(lflag, EXTPROC)) {
549 		/*
550 		 * Check for literal nexting very first
551 		 */
552 		if (ISSET(tp->t_state, TS_LNCH)) {
553 			SET(c, TTY_QUOTE);
554 			CLR(tp->t_state, TS_LNCH);
555 		}
556 		/*
557 		 * Scan for special characters.  This code
558 		 * is really just a big case statement with
559 		 * non-constant cases.  The bottom of the
560 		 * case statement is labeled ``endcase'', so goto
561 		 * it after a case match, or similar.
562 		 */
563 
564 		/*
565 		 * Control chars which aren't controlled
566 		 * by ICANON, ISIG, or IXON.
567 		 */
568 		if (ISSET(lflag, IEXTEN)) {
569 			if (CCEQ(cc[VLNEXT], c)) {
570 				if (ISSET(lflag, ECHO)) {
571 					if (ISSET(lflag, ECHOE)) {
572 						(void)ttyoutput('^', tp);
573 						(void)ttyoutput('\b', tp);
574 					} else
575 						ttyecho(c, tp);
576 				}
577 				SET(tp->t_state, TS_LNCH);
578 				goto endcase;
579 			}
580 			if (CCEQ(cc[VDISCARD], c)) {
581 				if (ISSET(lflag, FLUSHO))
582 					CLR(tp->t_lflag, FLUSHO);
583 				else {
584 					ttyflush(tp, FWRITE);
585 					ttyecho(c, tp);
586 					if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
587 						ttyretype(tp);
588 					SET(tp->t_lflag, FLUSHO);
589 				}
590 				goto startoutput;
591 			}
592 		}
593 		/*
594 		 * Signals.
595 		 */
596 		if (ISSET(lflag, ISIG)) {
597 			if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
598 				if (!ISSET(lflag, NOFLSH))
599 					ttyflush(tp, FREAD | FWRITE);
600 				ttyecho(c, tp);
601 				ttysig(tp, TTYSIG_PG1, CCEQ(cc[VINTR], c) ?
602 				    SIGINT : SIGQUIT);
603 				goto endcase;
604 			}
605 			if (CCEQ(cc[VSUSP], c)) {
606 				if (!ISSET(lflag, NOFLSH))
607 					ttyflush(tp, FREAD);
608 				ttyecho(c, tp);
609 				ttysig(tp, TTYSIG_PG1, SIGTSTP);
610 				goto endcase;
611 			}
612 		}
613 		/*
614 		 * Handle start/stop characters.
615 		 */
616 		if (ISSET(iflag, IXON)) {
617 			if (CCEQ(cc[VSTOP], c)) {
618 				if (!ISSET(tp->t_state, TS_TTSTOP)) {
619 					SET(tp->t_state, TS_TTSTOP);
620 					cdev_stop(tp, 0);
621 					return (0);
622 				}
623 				if (!CCEQ(cc[VSTART], c))
624 					return (0);
625 				/*
626 				 * if VSTART == VSTOP then toggle
627 				 */
628 				goto endcase;
629 			}
630 			if (CCEQ(cc[VSTART], c))
631 				goto restartoutput;
632 		}
633 		/*
634 		 * IGNCR, ICRNL, & INLCR
635 		 */
636 		if (c == '\r') {
637 			if (ISSET(iflag, IGNCR))
638 				goto endcase;
639 			else if (ISSET(iflag, ICRNL))
640 				c = '\n';
641 		} else if (c == '\n' && ISSET(iflag, INLCR))
642 			c = '\r';
643 	}
644 	if (!ISSET(lflag, EXTPROC) && ISSET(lflag, ICANON)) {
645 		/*
646 		 * From here on down canonical mode character
647 		 * processing takes place.
648 		 */
649 		/*
650 		 * erase (^H / ^?)
651 		 */
652 		if (CCEQ(cc[VERASE], c)) {
653 			if (tp->t_rawq.c_cc)
654 				ttyrub(unputc(&tp->t_rawq), tp);
655 			goto endcase;
656 		}
657 		/*
658 		 * kill (^U)
659 		 */
660 		if (CCEQ(cc[VKILL], c)) {
661 			if (ISSET(lflag, ECHOKE) &&
662 			    tp->t_rawq.c_cc == tp->t_rocount &&
663 			    !ISSET(lflag, ECHOPRT))
664 				while (tp->t_rawq.c_cc)
665 					ttyrub(unputc(&tp->t_rawq), tp);
666 			else {
667 				ttyecho(c, tp);
668 				if (ISSET(lflag, ECHOK) ||
669 				    ISSET(lflag, ECHOKE))
670 					ttyecho('\n', tp);
671 				FLUSHQ(&tp->t_rawq);
672 				tp->t_rocount = 0;
673 			}
674 			CLR(tp->t_state, TS_LOCAL);
675 			goto endcase;
676 		}
677 		/*
678 		 * Extensions to the POSIX.1 GTI set of functions.
679 		 */
680 		if (ISSET(lflag, IEXTEN)) {
681 			/*
682 			 * word erase (^W)
683 			 */
684 			if (CCEQ(cc[VWERASE], c)) {
685 				int alt = ISSET(lflag, ALTWERASE);
686 				int ctype;
687 
688 				/*
689 				 * erase whitespace
690 				 */
691 				while ((c = unputc(&tp->t_rawq)) == ' ' ||
692 				    c == '\t')
693 					ttyrub(c, tp);
694 				if (c == -1)
695 					goto endcase;
696 				/*
697 				 * erase last char of word and remember the
698 				 * next chars type (for ALTWERASE)
699 				 */
700 				ttyrub(c, tp);
701 				c = unputc(&tp->t_rawq);
702 				if (c == -1)
703 					goto endcase;
704 				if (c == ' ' || c == '\t') {
705 					(void)putc(c, &tp->t_rawq);
706 					goto endcase;
707 				}
708 				ctype = ISALPHA(c);
709 				/*
710 				 * erase rest of word
711 				 */
712 				do {
713 					ttyrub(c, tp);
714 					c = unputc(&tp->t_rawq);
715 					if (c == -1)
716 						goto endcase;
717 				} while (c != ' ' && c != '\t' &&
718 				    (alt == 0 || ISALPHA(c) == ctype));
719 				(void)putc(c, &tp->t_rawq);
720 				goto endcase;
721 			}
722 			/*
723 			 * reprint line (^R)
724 			 */
725 			if (CCEQ(cc[VREPRINT], c)) {
726 				ttyretype(tp);
727 				goto endcase;
728 			}
729 			/*
730 			 * ^T - kernel info and generate SIGINFO
731 			 */
732 			if (CCEQ(cc[VSTATUS], c)) {
733 				ttysig(tp, TTYSIG_PG1, SIGINFO);
734 				goto endcase;
735 			}
736 		}
737 	}
738 	/*
739 	 * Check for input buffer overflow
740 	 */
741 	if (tp->t_rawq.c_cc + tp->t_canq.c_cc >= TTYHOG) {
742 		if (ISSET(iflag, IMAXBEL)) {
743 			if (tp->t_outq.c_cc < tp->t_hiwat)
744 				(void)ttyoutput(CTRL('g'), tp);
745 		} else
746 			ttyflush(tp, FREAD | FWRITE);
747 		goto endcase;
748 	}
749 	/*
750 	 * Put data char in q for user and
751 	 * wakeup on seeing a line delimiter.
752 	 */
753 	if (putc(c, &tp->t_rawq) >= 0) {
754 		if (!ISSET(lflag, ICANON)) {
755 			ttwakeup(tp);
756 			ttyecho(c, tp);
757 			goto endcase;
758 		}
759 		if (TTBREAKC(c, lflag)) {
760 			tp->t_rocount = 0;
761 			catq(&tp->t_rawq, &tp->t_canq);
762 			ttwakeup(tp);
763 		} else if (tp->t_rocount++ == 0)
764 			tp->t_rocol = tp->t_column;
765 		if (ISSET(tp->t_state, TS_ERASE)) {
766 			/*
767 			 * end of prterase \.../
768 			 */
769 			CLR(tp->t_state, TS_ERASE);
770 			(void)ttyoutput('/', tp);
771 		}
772 		i = tp->t_column;
773 		ttyecho(c, tp);
774 		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ECHO)) {
775 			/*
776 			 * Place the cursor over the '^' of the ^D.
777 			 */
778 			i = uimin(2, tp->t_column - i);
779 			while (i > 0) {
780 				(void)ttyoutput('\b', tp);
781 				i--;
782 			}
783 		}
784 	}
785  endcase:
786 	/*
787 	 * IXANY means allow any character to restart output.
788 	 */
789 	if (ISSET(tp->t_state, TS_TTSTOP) &&
790 	    !ISSET(iflag, IXANY) && cc[VSTART] != cc[VSTOP]) {
791 		return (0);
792 	}
793  restartoutput:
794 	CLR(tp->t_lflag, FLUSHO);
795 	CLR(tp->t_state, TS_TTSTOP);
796  startoutput:
797 	return (ttstart(tp));
798 }
799 
800 /*
801  * Process input of a single character received on a tty.
802  *
803  * XXX - this is a hack, all drivers must changed to acquire the
804  *	 lock before calling linesw->l_rint()
805  */
806 int
807 ttyinput(int c, struct tty *tp)
808 {
809 	int error;
810 
811 	/*
812 	 * Unless the receiver is enabled, drop incoming data.
813 	 */
814 	if (!ISSET(tp->t_cflag, CREAD))
815 		return (0);
816 
817 	mutex_spin_enter(&tty_lock);
818 	error = ttyinput_wlock(c, tp);
819 	mutex_spin_exit(&tty_lock);
820 
821 	return (error);
822 }
823 
824 /*
825  * Output a single character on a tty, doing output processing
826  * as needed (expanding tabs, newline processing, etc.).
827  * Returns < 0 if succeeds, otherwise returns char to resend.
828  * Must be recursive.
829  *
830  * Call with tty lock held.
831  */
832 int
833 ttyoutput(int c, struct tty *tp)
834 {
835 	long	oflag;
836 	int	col, notout;
837 
838 	KASSERT(mutex_owned(&tty_lock));
839 
840 	oflag = tp->t_oflag;
841 	if (!ISSET(oflag, OPOST)) {
842 		tk_nout++;
843 		tp->t_outcc++;
844 		if (!ISSET(tp->t_lflag, FLUSHO) && putc(c, &tp->t_outq))
845 			return (c);
846 		return (-1);
847 	}
848 	/*
849 	 * Do tab expansion if OXTABS is set.  Special case if we do external
850 	 * processing, we don't do the tab expansion because we'll probably
851 	 * get it wrong.  If tab expansion needs to be done, let it happen
852 	 * externally.
853 	 */
854 	CLR(c, ~TTY_CHARMASK);
855 	if (c == '\t' &&
856 	    ISSET(oflag, OXTABS) && !ISSET(tp->t_lflag, EXTPROC)) {
857 		c = 8 - (tp->t_column & 7);
858 		if (ISSET(tp->t_lflag, FLUSHO)) {
859 			notout = 0;
860 		} else {
861 			notout = b_to_q("        ", c, &tp->t_outq);
862 			c -= notout;
863 			tk_nout += c;
864 			tp->t_outcc += c;
865 		}
866 		tp->t_column += c;
867 		return (notout ? '\t' : -1);
868 	}
869 	if (c == CEOT && ISSET(oflag, ONOEOT))
870 		return (-1);
871 
872 	/*
873 	 * Newline translation: if ONLCR is set,
874 	 * translate newline into "\r\n".
875 	 */
876 	if (c == '\n' && ISSET(tp->t_oflag, ONLCR)) {
877 		tk_nout++;
878 		tp->t_outcc++;
879 		if (!ISSET(tp->t_lflag, FLUSHO) && putc('\r', &tp->t_outq))
880 			return (c);
881 	}
882 	/* If OCRNL is set, translate "\r" into "\n". */
883 	else if (c == '\r' && ISSET(tp->t_oflag, OCRNL))
884 		c = '\n';
885 	/* If ONOCR is set, don't transmit CRs when on column 0. */
886 	else if (c == '\r' && ISSET(tp->t_oflag, ONOCR) && tp->t_column == 0)
887 		return (-1);
888 
889 	tk_nout++;
890 	tp->t_outcc++;
891 	if (!ISSET(tp->t_lflag, FLUSHO) && putc(c, &tp->t_outq))
892 		return (c);
893 
894 	col = tp->t_column;
895 	switch (CCLASS(c)) {
896 	case BACKSPACE:
897 		if (col > 0)
898 			--col;
899 		break;
900 	case CONTROL:
901 		break;
902 	case NEWLINE:
903 		if (ISSET(tp->t_oflag, ONLCR | ONLRET))
904 			col = 0;
905 		break;
906 	case RETURN:
907 		col = 0;
908 		break;
909 	case ORDINARY:
910 		++col;
911 		break;
912 	case TAB:
913 		col = (col + 8) & ~7;
914 		break;
915 	}
916 	tp->t_column = col;
917 	return (-1);
918 }
919 
920 /*
921  * Ioctls for all tty devices.  Called after line-discipline specific ioctl
922  * has been called to do discipline-specific functions and/or reject any
923  * of these ioctl commands.
924  */
925 /* ARGSUSED */
926 int
927 ttioctl(struct tty *tp, u_long cmd, void *data, int flag, struct lwp *l)
928 {
929 	extern struct tty *constty;	/* Temporary virtual console. */
930 	struct proc *p;
931 	struct linesw	*lp;
932 	int		s, error;
933 	struct pathbuf *pb;
934 	struct nameidata nd;
935 	char		infobuf[200];
936 
937 	KASSERT(l != NULL);
938 	p = l->l_proc;
939 
940 	/* If the ioctl involves modification, hang if in the background. */
941 	switch (cmd) {
942 	case  TIOCFLUSH:
943 	case  TIOCDRAIN:
944 	case  TIOCSBRK:
945 	case  TIOCCBRK:
946 	case  TIOCSTART:
947 	case  TIOCSETA:
948 	case  TIOCSETD:
949 	case  TIOCSLINED:
950 	case  TIOCSETAF:
951 	case  TIOCSETAW:
952 #ifdef notdef
953 	case  TIOCSPGRP:
954 	case  FIOSETOWN:
955 #endif
956 	case  TIOCSTAT:
957 	case  TIOCSTI:
958 	case  TIOCSWINSZ:
959 	case  TIOCSQSIZE:
960 	case  TIOCLBIC:
961 	case  TIOCLBIS:
962 	case  TIOCLSET:
963 	case  TIOCSETC:
964 	case OTIOCSETD:
965 	case  TIOCSETN:
966 	case  TIOCSETP:
967 	case  TIOCSLTC:
968 		mutex_spin_enter(&tty_lock);
969 		while (isbackground(curproc, tp) &&
970 		    p->p_pgrp->pg_jobc && (p->p_lflag & PL_PPWAIT) == 0 &&
971 		    !sigismasked(l, SIGTTOU)) {
972 			mutex_spin_exit(&tty_lock);
973 
974 			mutex_enter(&proc_lock);
975 			pgsignal(p->p_pgrp, SIGTTOU, 1);
976 			mutex_exit(&proc_lock);
977 
978 			mutex_spin_enter(&tty_lock);
979 			error = ttypause(tp, hz);
980 			if (error) {
981 				mutex_spin_exit(&tty_lock);
982 				return (error);
983 			}
984 		}
985 		mutex_spin_exit(&tty_lock);
986 		break;
987 	}
988 
989 	switch (cmd) {			/* Process the ioctl. */
990 	case FIOASYNC:			/* set/clear async i/o */
991 		mutex_spin_enter(&tty_lock);
992 		if (*(int *)data)
993 			SET(tp->t_state, TS_ASYNC);
994 		else
995 			CLR(tp->t_state, TS_ASYNC);
996 		mutex_spin_exit(&tty_lock);
997 		break;
998 	case FIONBIO:			/* set/clear non-blocking i/o */
999 		break;			/* XXX: delete. */
1000 	case FIONREAD:			/* get # bytes to read */
1001 		mutex_spin_enter(&tty_lock);
1002 		*(int *)data = ttnread(tp);
1003 		mutex_spin_exit(&tty_lock);
1004 		break;
1005 	case FIONWRITE:			/* get # bytes to written & unsent */
1006 		mutex_spin_enter(&tty_lock);
1007 		*(int *)data = tp->t_outq.c_cc;
1008 		mutex_spin_exit(&tty_lock);
1009 		break;
1010 	case FIONSPACE:			/* get # bytes to written & unsent */
1011 		mutex_spin_enter(&tty_lock);
1012 		*(int *)data = tp->t_outq.c_cn - tp->t_outq.c_cc;
1013 		mutex_spin_exit(&tty_lock);
1014 		break;
1015 	case TIOCEXCL:			/* set exclusive use of tty */
1016 		mutex_spin_enter(&tty_lock);
1017 		SET(tp->t_state, TS_XCLUDE);
1018 		mutex_spin_exit(&tty_lock);
1019 		break;
1020 	case TIOCFLUSH: {		/* flush buffers */
1021 		int flags = *(int *)data;
1022 
1023 		if (flags == 0)
1024 			flags = FREAD | FWRITE;
1025 		else
1026 			flags &= FREAD | FWRITE;
1027 		mutex_spin_enter(&tty_lock);
1028 		ttyflush(tp, flags);
1029 		mutex_spin_exit(&tty_lock);
1030 		break;
1031 	}
1032 	case TIOCCONS:			/* become virtual console */
1033 		if (*(int *)data) {
1034 			if (constty && constty != tp &&
1035 			    ISSET(constty->t_state, TS_CARR_ON | TS_ISOPEN) ==
1036 			    (TS_CARR_ON | TS_ISOPEN))
1037 				return EBUSY;
1038 
1039 			pb = pathbuf_create("/dev/console");
1040 			if (pb == NULL) {
1041 				return ENOMEM;
1042 			}
1043 			NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, pb);
1044 			if ((error = namei(&nd)) != 0) {
1045 				pathbuf_destroy(pb);
1046 				return error;
1047 			}
1048 			error = VOP_ACCESS(nd.ni_vp, VREAD, l->l_cred);
1049 			vput(nd.ni_vp);
1050 			pathbuf_destroy(pb);
1051 			if (error)
1052 				return error;
1053 
1054 			constty = tp;
1055 		} else if (tp == constty)
1056 			constty = NULL;
1057 		break;
1058 	case TIOCDRAIN:			/* wait till output drained */
1059 		if ((error = ttywait(tp)) != 0)
1060 			return (error);
1061 		break;
1062 	case TIOCGETA: {		/* get termios struct */
1063 		struct termios *t = (struct termios *)data;
1064 
1065 		memcpy(t, &tp->t_termios, sizeof(struct termios));
1066 		break;
1067 	}
1068 	case TIOCGETD:			/* get line discipline (old) */
1069 		*(int *)data = tp->t_linesw->l_no;
1070 		break;
1071 	case TIOCGLINED:		/* get line discipline (new) */
1072 		(void)strncpy((char *)data, tp->t_linesw->l_name,
1073 		    TTLINEDNAMELEN - 1);
1074 		break;
1075 	case TIOCGWINSZ:		/* get window size */
1076 		*(struct winsize *)data = tp->t_winsize;
1077 		break;
1078 	case TIOCGQSIZE:
1079 		*(int *)data = tp->t_qsize;
1080 		break;
1081 	case FIOGETOWN:
1082 		mutex_enter(&proc_lock);
1083 		if (tp->t_session != NULL && !isctty(p, tp)) {
1084 			mutex_exit(&proc_lock);
1085 			return (ENOTTY);
1086 		}
1087 		*(int *)data = tp->t_pgrp ? -tp->t_pgrp->pg_id : 0;
1088 		mutex_exit(&proc_lock);
1089 		break;
1090 	case TIOCGPGRP:			/* get pgrp of tty */
1091 		mutex_enter(&proc_lock);
1092 		if (!isctty(p, tp)) {
1093 			mutex_exit(&proc_lock);
1094 			return (ENOTTY);
1095 		}
1096 		*(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PGID;
1097 		mutex_exit(&proc_lock);
1098 		break;
1099 	case TIOCGSID:			/* get sid of tty */
1100 		mutex_enter(&proc_lock);
1101 		if (!isctty(p, tp)) {
1102 			mutex_exit(&proc_lock);
1103 			return (ENOTTY);
1104 		}
1105 		*(int *)data = tp->t_session->s_sid;
1106 		mutex_exit(&proc_lock);
1107 		break;
1108 #ifdef TIOCHPCL
1109 	case TIOCHPCL:			/* hang up on last close */
1110 		mutex_spin_enter(&tty_lock);
1111 		SET(tp->t_cflag, HUPCL);
1112 		mutex_spin_exit(&tty_lock);
1113 		break;
1114 #endif
1115 	case TIOCNXCL:			/* reset exclusive use of tty */
1116 		mutex_spin_enter(&tty_lock);
1117 		CLR(tp->t_state, TS_XCLUDE);
1118 		mutex_spin_exit(&tty_lock);
1119 		break;
1120 	case TIOCOUTQ:			/* output queue size */
1121 		*(int *)data = tp->t_outq.c_cc;
1122 		break;
1123 	case TIOCSETA:			/* set termios struct */
1124 	case TIOCSETAW:			/* drain output, set */
1125 	case TIOCSETAF: {		/* drn out, fls in, set */
1126 		struct termios *t = (struct termios *)data;
1127 
1128 		if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1129 			if ((error = ttywait(tp)) != 0)
1130 				return (error);
1131 
1132 			if (cmd == TIOCSETAF) {
1133 				mutex_spin_enter(&tty_lock);
1134 				ttyflush(tp, FREAD);
1135 				mutex_spin_exit(&tty_lock);
1136 			}
1137 		}
1138 
1139 		s = spltty();
1140 		/*
1141 		 * XXXSMP - some drivers call back on us from t_param(), so
1142 		 *	    don't take the tty spin lock here.
1143 		 *	    require t_param() to unlock upon callback?
1144 		 */
1145 		/* wanted here: mutex_spin_enter(&tty_lock); */
1146 		if (!ISSET(t->c_cflag, CIGNORE)) {
1147 			/*
1148 			 * Set device hardware.
1149 			 */
1150 			if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
1151 				/* wanted here: mutex_spin_exit(&tty_lock); */
1152 				splx(s);
1153 				return (error);
1154 			} else {
1155 				tp->t_cflag = t->c_cflag;
1156 				tp->t_ispeed = t->c_ispeed;
1157 				tp->t_ospeed = t->c_ospeed;
1158 				if (t->c_ospeed == 0)
1159 					ttysig(tp, TTYSIG_LEADER, SIGHUP);
1160 			}
1161 			ttsetwater(tp);
1162 		}
1163 
1164 		/* delayed lock acquiring */
1165 		mutex_spin_enter(&tty_lock);
1166 		if (cmd != TIOCSETAF) {
1167 			if (ISSET(t->c_lflag, ICANON) !=
1168 			    ISSET(tp->t_lflag, ICANON)) {
1169 				if (ISSET(t->c_lflag, ICANON)) {
1170 					SET(tp->t_lflag, PENDIN);
1171 					ttwakeup(tp);
1172 				} else {
1173 					struct clist tq;
1174 
1175 					catq(&tp->t_rawq, &tp->t_canq);
1176 					tq = tp->t_rawq;
1177 					tp->t_rawq = tp->t_canq;
1178 					tp->t_canq = tq;
1179 					CLR(tp->t_lflag, PENDIN);
1180 				}
1181 			}
1182 		}
1183 		tp->t_iflag = t->c_iflag;
1184 		tp->t_oflag = t->c_oflag;
1185 		/*
1186 		 * Make the EXTPROC bit read only.
1187 		 */
1188 		if (ISSET(tp->t_lflag, EXTPROC))
1189 			SET(t->c_lflag, EXTPROC);
1190 		else
1191 			CLR(t->c_lflag, EXTPROC);
1192 		tp->t_lflag = t->c_lflag | ISSET(tp->t_lflag, PENDIN);
1193 		memcpy(tp->t_cc, t->c_cc, sizeof(t->c_cc));
1194 		mutex_spin_exit(&tty_lock);
1195 		splx(s);
1196 		break;
1197 	}
1198 	case TIOCSETD:			/* set line discipline (old) */
1199 		lp = ttyldisc_lookup_bynum(*(int *)data);
1200 		goto setldisc;
1201 
1202 	case TIOCSLINED: {		/* set line discipline (new) */
1203 		char *name = (char *)data;
1204 		dev_t device;
1205 
1206 		/* Null terminate to prevent buffer overflow */
1207 		name[TTLINEDNAMELEN - 1] = '\0';
1208 		lp = ttyldisc_lookup(name);
1209  setldisc:
1210 		if (lp == NULL)
1211 			return (ENXIO);
1212 
1213 		if (lp != tp->t_linesw) {
1214 			device = tp->t_dev;
1215 			s = spltty();
1216 			(*tp->t_linesw->l_close)(tp, flag);
1217 			error = (*lp->l_open)(device, tp);
1218 			if (error) {
1219 				(void)(*tp->t_linesw->l_open)(device, tp);
1220 				splx(s);
1221 				ttyldisc_release(lp);
1222 				return (error);
1223 			}
1224 			ttyldisc_release(tp->t_linesw);
1225 			tp->t_linesw = lp;
1226 			splx(s);
1227 		} else {
1228 			/* Drop extra reference. */
1229 			ttyldisc_release(lp);
1230 		}
1231 		break;
1232 	}
1233 	case TIOCSTART:			/* start output, like ^Q */
1234 		mutex_spin_enter(&tty_lock);
1235 		if (ISSET(tp->t_state, TS_TTSTOP) ||
1236 		    ISSET(tp->t_lflag, FLUSHO)) {
1237 			CLR(tp->t_lflag, FLUSHO);
1238 			CLR(tp->t_state, TS_TTSTOP);
1239 			ttstart(tp);
1240 		}
1241 		mutex_spin_exit(&tty_lock);
1242 		break;
1243 	case TIOCSTI:			/* simulate terminal input */
1244 		if ((error = kauth_authorize_device_tty(l->l_cred,
1245 		    KAUTH_DEVICE_TTY_STI, tp)) != 0) {
1246 			if (!ISSET(flag, FREAD))
1247 				return EPERM;
1248 			if (!isctty(p, tp))
1249 				return EACCES;
1250 			if (tp->t_session->s_leader->p_cred != p->p_cred)
1251 				return error;
1252 		}
1253 		(*tp->t_linesw->l_rint)(*(u_char *)data, tp);
1254 		break;
1255 	case TIOCSTOP:			/* stop output, like ^S */
1256 	{
1257 		mutex_spin_enter(&tty_lock);
1258 		if (!ISSET(tp->t_state, TS_TTSTOP)) {
1259 			SET(tp->t_state, TS_TTSTOP);
1260 			cdev_stop(tp, 0);
1261 		}
1262 		mutex_spin_exit(&tty_lock);
1263 		break;
1264 	}
1265 	case TIOCSCTTY:			/* become controlling tty */
1266 		mutex_enter(&proc_lock);
1267 		mutex_spin_enter(&tty_lock);
1268 
1269 		/* Session ctty vnode pointer set in vnode layer. */
1270 		if (!SESS_LEADER(p) ||
1271 		    ((p->p_session->s_ttyvp || tp->t_session) &&
1272 		    (tp->t_session != p->p_session))) {
1273 			mutex_spin_exit(&tty_lock);
1274 			mutex_exit(&proc_lock);
1275 			return (EPERM);
1276 		}
1277 
1278 		/*
1279 		 * `p_session' acquires a reference.
1280 		 * But note that if `t_session' is set at this point,
1281 		 * it must equal `p_session', in which case the session
1282 		 * already has the correct reference count.
1283 		 */
1284 		if (tp->t_session == NULL) {
1285 			proc_sesshold(p->p_session);
1286 		}
1287 		tp->t_session = p->p_session;
1288 		tp->t_pgrp = p->p_pgrp;
1289 		p->p_session->s_ttyp = tp;
1290 		p->p_lflag |= PL_CONTROLT;
1291 		mutex_spin_exit(&tty_lock);
1292 		mutex_exit(&proc_lock);
1293 		break;
1294 	case FIOSETOWN: {		/* set pgrp of tty */
1295 		pid_t pgid = *(pid_t *)data;
1296 		struct pgrp *pgrp;
1297 
1298 		mutex_enter(&proc_lock);
1299 		if (tp->t_session != NULL && !isctty(p, tp)) {
1300 			mutex_exit(&proc_lock);
1301 			return (ENOTTY);
1302 		}
1303 
1304 		if (pgid < 0) {
1305 			if (pgid == INT_MIN) {
1306 				mutex_exit(&proc_lock);
1307 				return (EINVAL);
1308 			}
1309 			pgrp = pgrp_find(-pgid);
1310 			if (pgrp == NULL) {
1311 				mutex_exit(&proc_lock);
1312 				return (EINVAL);
1313 			}
1314 		} else {
1315 			struct proc *p1;
1316 			p1 = proc_find(pgid);
1317 			if (!p1) {
1318 				mutex_exit(&proc_lock);
1319 				return (ESRCH);
1320 			}
1321 			pgrp = p1->p_pgrp;
1322 		}
1323 
1324 		if (pgrp->pg_session != p->p_session) {
1325 			mutex_exit(&proc_lock);
1326 			return (EPERM);
1327 		}
1328 		mutex_spin_enter(&tty_lock);
1329 		tp->t_pgrp = pgrp;
1330 		mutex_spin_exit(&tty_lock);
1331 		mutex_exit(&proc_lock);
1332 		break;
1333 	}
1334 	case TIOCSPGRP: {		/* set pgrp of tty */
1335 		struct pgrp *pgrp;
1336 		pid_t pgid = *(pid_t *)data;
1337 
1338 		if (pgid == NO_PGID)
1339 			return EINVAL;
1340 
1341 		mutex_enter(&proc_lock);
1342 		if (!isctty(p, tp)) {
1343 			mutex_exit(&proc_lock);
1344 			return (ENOTTY);
1345 		}
1346 		pgrp = pgrp_find(pgid);
1347 		if (pgrp == NULL || pgrp->pg_session != p->p_session) {
1348 			mutex_exit(&proc_lock);
1349 			return (EPERM);
1350 		}
1351 		mutex_spin_enter(&tty_lock);
1352 		tp->t_pgrp = pgrp;
1353 		mutex_spin_exit(&tty_lock);
1354 		mutex_exit(&proc_lock);
1355 		break;
1356 	}
1357 	case TIOCSTAT:			/* get load avg stats */
1358 		mutex_enter(&proc_lock);
1359 		ttygetinfo(tp, 0, infobuf, sizeof(infobuf));
1360 		mutex_exit(&proc_lock);
1361 
1362 		mutex_spin_enter(&tty_lock);
1363 		ttyputinfo(tp, infobuf);
1364 		mutex_spin_exit(&tty_lock);
1365 		break;
1366 	case TIOCSWINSZ:		/* set window size */
1367 		mutex_spin_enter(&tty_lock);
1368 		if (memcmp((void *)&tp->t_winsize, data,
1369 		    sizeof(struct winsize))) {
1370 			tp->t_winsize = *(struct winsize *)data;
1371 			ttysig(tp, TTYSIG_PG1, SIGWINCH);
1372 		}
1373 		mutex_spin_exit(&tty_lock);
1374 		break;
1375 	case TIOCSQSIZE:
1376 		if ((error = tty_get_qsize(&s, *(int *)data)) == 0 &&
1377 		    s != tp->t_qsize)
1378 			error = tty_set_qsize(tp, s);
1379 		return error;
1380 
1381 	case TIOCSBRK:
1382 	case TIOCCBRK:
1383 	case TIOCSDTR:
1384 	case TIOCCDTR:
1385 	case TIOCSFLAGS:
1386 	case TIOCGFLAGS:
1387 	case TIOCMSET:
1388 	case TIOCMGET:
1389 	case TIOCMBIS:
1390 	case TIOCMBIC:
1391 		/* Handled by the driver layer */
1392 		return EPASSTHROUGH;
1393 
1394 	case TIOCEXT:
1395 	case TIOCPTSNAME:
1396 	case TIOCGRANTPT:
1397 	case TIOCPKT:
1398 	case TIOCUCNTL:
1399 	case TIOCREMOTE:
1400 	case TIOCSIG:
1401 		/* for ptys */
1402 		return EPASSTHROUGH;
1403 
1404 	default:
1405 		/* Pass through various console ioctls */
1406 		switch (IOCGROUP(cmd)) {
1407 		case 'c':	/* syscons console */
1408 		case 'v':	/* usl console, video - where one letter */
1409 		case 'K':	/* usl console, keyboard - aint enough */
1410 		case 'V':	/* pcvt compat */
1411 		case 'W':	/* wscons console */
1412 			return EPASSTHROUGH;
1413 		default:
1414 			break;
1415 		}
1416 
1417 		/* We may have to load the compat_60 module for this. */
1418 		(void)module_autoload("compat_60", MODULE_CLASS_EXEC);
1419 		MODULE_HOOK_CALL(tty_ttioctl_60_hook,
1420 		    (tp, cmd, data, flag, l), enosys(), error);
1421 		if (error != EPASSTHROUGH)
1422 			return error;
1423 
1424 		/* We may have to load the compat_43 module for this. */
1425 		(void)module_autoload("compat_43", MODULE_CLASS_EXEC);
1426 		MODULE_HOOK_CALL(tty_ttioctl_43_hook,
1427 		    (tp, cmd, data, flag, l), enosys(), error);
1428 		return error;
1429 	}
1430 	return (0);
1431 }
1432 
1433 int
1434 ttpoll(struct tty *tp, int events, struct lwp *l)
1435 {
1436 	int	revents;
1437 
1438 	revents = 0;
1439 	mutex_spin_enter(&tty_lock);
1440 	if (events & (POLLIN | POLLRDNORM))
1441 		if (ttnread(tp) > 0)
1442 			revents |= events & (POLLIN | POLLRDNORM);
1443 
1444 	if (events & (POLLOUT | POLLWRNORM))
1445 		if (tp->t_outq.c_cc <= tp->t_lowat)
1446 			revents |= events & (POLLOUT | POLLWRNORM);
1447 
1448 	if (events & POLLHUP)
1449 		if (!CONNECTED(tp))
1450 			revents |= POLLHUP;
1451 
1452 	if (revents == 0) {
1453 		if (events & (POLLIN | POLLHUP | POLLRDNORM))
1454 			selrecord(l, &tp->t_rsel);
1455 
1456 		if (events & (POLLOUT | POLLWRNORM))
1457 			selrecord(l, &tp->t_wsel);
1458 	}
1459 
1460 	mutex_spin_exit(&tty_lock);
1461 
1462 	return (revents);
1463 }
1464 
1465 static void
1466 filt_ttyrdetach(struct knote *kn)
1467 {
1468 	struct tty	*tp;
1469 
1470 	tp = kn->kn_hook;
1471 	mutex_spin_enter(&tty_lock);
1472 	selremove_knote(&tp->t_rsel, kn);
1473 	mutex_spin_exit(&tty_lock);
1474 }
1475 
1476 static int
1477 filt_ttyread(struct knote *kn, long hint)
1478 {
1479 	struct tty	*tp;
1480 
1481 	tp = kn->kn_hook;
1482 	if ((hint & NOTE_SUBMIT) == 0)
1483 		mutex_spin_enter(&tty_lock);
1484 	kn->kn_data = ttnread(tp);
1485 	if ((hint & NOTE_SUBMIT) == 0)
1486 		mutex_spin_exit(&tty_lock);
1487 	return (kn->kn_data > 0);
1488 }
1489 
1490 static void
1491 filt_ttywdetach(struct knote *kn)
1492 {
1493 	struct tty	*tp;
1494 
1495 	tp = kn->kn_hook;
1496 	mutex_spin_enter(&tty_lock);
1497 	selremove_knote(&tp->t_wsel, kn);
1498 	mutex_spin_exit(&tty_lock);
1499 }
1500 
1501 static int
1502 filt_ttywrite(struct knote *kn, long hint)
1503 {
1504 	struct tty	*tp;
1505 	int		canwrite;
1506 
1507 	tp = kn->kn_hook;
1508 	if ((hint & NOTE_SUBMIT) == 0)
1509 		mutex_spin_enter(&tty_lock);
1510 	kn->kn_data = tp->t_outq.c_cn - tp->t_outq.c_cc;
1511 	canwrite = (tp->t_outq.c_cc <= tp->t_lowat) && CONNECTED(tp);
1512 	if ((hint & NOTE_SUBMIT) == 0)
1513 		mutex_spin_exit(&tty_lock);
1514 	return (canwrite);
1515 }
1516 
1517 static const struct filterops ttyread_filtops = {
1518 	.f_isfd = 1,
1519 	.f_attach = NULL,
1520 	.f_detach = filt_ttyrdetach,
1521 	.f_event = filt_ttyread,
1522 };
1523 
1524 static const struct filterops ttywrite_filtops = {
1525 	.f_isfd = 1,
1526 	.f_attach = NULL,
1527 	.f_detach = filt_ttywdetach,
1528 	.f_event = filt_ttywrite,
1529 };
1530 
1531 int
1532 ttykqfilter(dev_t dev, struct knote *kn)
1533 {
1534 	struct tty	*tp;
1535 	struct selinfo	*sip;
1536 
1537 	if ((tp = cdev_tty(dev)) == NULL)
1538 		return (ENXIO);
1539 
1540 	switch (kn->kn_filter) {
1541 	case EVFILT_READ:
1542 		sip = &tp->t_rsel;
1543 		kn->kn_fop = &ttyread_filtops;
1544 		break;
1545 	case EVFILT_WRITE:
1546 		sip = &tp->t_wsel;
1547 		kn->kn_fop = &ttywrite_filtops;
1548 		break;
1549 	default:
1550 		return EINVAL;
1551 	}
1552 
1553 	kn->kn_hook = tp;
1554 
1555 	mutex_spin_enter(&tty_lock);
1556 	selrecord_knote(sip, kn);
1557 	mutex_spin_exit(&tty_lock);
1558 
1559 	return (0);
1560 }
1561 
1562 /*
1563  * Find the number of chars ready to be read from this tty.
1564  * Call with the tty lock held.
1565  */
1566 static int
1567 ttnread(struct tty *tp)
1568 {
1569 	int	nread;
1570 
1571 	KASSERT(mutex_owned(&tty_lock));
1572 
1573 	if (ISSET(tp->t_lflag, PENDIN))
1574 		ttypend(tp);
1575 	nread = tp->t_canq.c_cc;
1576 	if (!ISSET(tp->t_lflag, ICANON)) {
1577 		nread += tp->t_rawq.c_cc;
1578 		if (nread < tp->t_cc[VMIN] && !tp->t_cc[VTIME])
1579 			nread = 0;
1580 	}
1581 	return (nread);
1582 }
1583 
1584 /*
1585  * Wait for output to drain, or if this times out, flush it.
1586  */
1587 static int
1588 ttywait_timo(struct tty *tp, int timo)
1589 {
1590 	int	error;
1591 
1592 	error = 0;
1593 
1594 	mutex_spin_enter(&tty_lock);
1595 	while ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1596 	    CONNECTED(tp) && tp->t_oproc) {
1597 		(*tp->t_oproc)(tp);
1598 		error = ttysleep(tp, &tp->t_outcv, true, timo);
1599 		if (error == EWOULDBLOCK)
1600 			ttyflush(tp, FWRITE);
1601 		if (error)
1602 			break;
1603 	}
1604 	mutex_spin_exit(&tty_lock);
1605 
1606 	return (error);
1607 }
1608 
1609 /*
1610  * Wait for output to drain.
1611  */
1612 int
1613 ttywait(struct tty *tp)
1614 {
1615 	return ttywait_timo(tp, 0);
1616 }
1617 
1618 /*
1619  * Flush if successfully wait.
1620  */
1621 int
1622 ttywflush(struct tty *tp)
1623 {
1624 	int	error;
1625 
1626 	error = ttywait_timo(tp, 5 * hz);
1627 	if (error == 0 || error == EWOULDBLOCK) {
1628 		mutex_spin_enter(&tty_lock);
1629 		ttyflush(tp, FREAD);
1630 		mutex_spin_exit(&tty_lock);
1631 	}
1632 	return (error);
1633 }
1634 
1635 /*
1636  * Flush tty read and/or write queues, notifying anyone waiting.
1637  * Call with the tty lock held.
1638  */
1639 void
1640 ttyflush(struct tty *tp, int rw)
1641 {
1642 
1643 	KASSERT(mutex_owned(&tty_lock));
1644 
1645 	if (rw & FREAD) {
1646 		FLUSHQ(&tp->t_canq);
1647 		FLUSHQ(&tp->t_rawq);
1648 		tp->t_rocount = 0;
1649 		tp->t_rocol = 0;
1650 		CLR(tp->t_state, TS_LOCAL);
1651 		ttwakeup(tp);
1652 	}
1653 	if (rw & FWRITE) {
1654 		CLR(tp->t_state, TS_TTSTOP);
1655 		cdev_stop(tp, rw);
1656 		FLUSHQ(&tp->t_outq);
1657 		cv_broadcast(&tp->t_outcv);
1658 		selnotify(&tp->t_wsel, 0, NOTE_SUBMIT);
1659 	}
1660 }
1661 
1662 /*
1663  * Copy in the default termios characters.
1664  */
1665 void
1666 ttychars(struct tty *tp)
1667 {
1668 
1669 	memcpy(tp->t_cc, ttydefchars, sizeof(ttydefchars));
1670 }
1671 
1672 /*
1673  * Send stop character on input overflow.
1674  * Call with the tty lock held.
1675  */
1676 static void
1677 ttyblock(struct tty *tp)
1678 {
1679 	int	total;
1680 
1681 	KASSERT(mutex_owned(&tty_lock));
1682 
1683 	total = tp->t_rawq.c_cc + tp->t_canq.c_cc;
1684 	if (tp->t_rawq.c_cc > TTYHOG) {
1685 		ttyflush(tp, FREAD | FWRITE);
1686 		CLR(tp->t_state, TS_TBLOCK);
1687 	}
1688 	/*
1689 	 * Block further input iff: current input > threshold
1690 	 * AND input is available to user program.
1691 	 */
1692 	if (total >= TTYHOG / 2 &&
1693 	    !ISSET(tp->t_state, TS_TBLOCK) &&
1694 	    (!ISSET(tp->t_lflag, ICANON) || tp->t_canq.c_cc > 0)) {
1695 		if (ISSET(tp->t_iflag, IXOFF) &&
1696 		    tp->t_cc[VSTOP] != _POSIX_VDISABLE &&
1697 		    putc(tp->t_cc[VSTOP], &tp->t_outq) == 0) {
1698 			SET(tp->t_state, TS_TBLOCK);
1699 			ttstart(tp);
1700 		}
1701 		/* Try to block remote output via hardware flow control. */
1702 		if (ISSET(tp->t_cflag, CHWFLOW) && tp->t_hwiflow &&
1703 		    (*tp->t_hwiflow)(tp, 1) != 0)
1704 			SET(tp->t_state, TS_TBLOCK);
1705 	}
1706 }
1707 
1708 /*
1709  * Delayed line discipline output
1710  */
1711 void
1712 ttrstrt(void *tp_arg)
1713 {
1714 	struct tty	*tp;
1715 
1716 #ifdef DIAGNOSTIC
1717 	if (tp_arg == NULL)
1718 		panic("ttrstrt");
1719 #endif
1720 	tp = tp_arg;
1721 	mutex_spin_enter(&tty_lock);
1722 
1723 	CLR(tp->t_state, TS_TIMEOUT);
1724 	ttstart(tp); /* XXX - Shouldn't this be tp->l_start(tp)? */
1725 
1726 	mutex_spin_exit(&tty_lock);
1727 }
1728 
1729 /*
1730  * start a line discipline
1731  * Always call with tty lock held?
1732  */
1733 int
1734 ttstart(struct tty *tp)
1735 {
1736 
1737 	if (tp->t_oproc != NULL)	/* XXX: Kludge for pty. */
1738 		(*tp->t_oproc)(tp);
1739 	return (0);
1740 }
1741 
1742 /*
1743  * "close" a line discipline
1744  */
1745 int
1746 ttylclose(struct tty *tp, int flag)
1747 {
1748 
1749 	if (flag & FNONBLOCK) {
1750 		mutex_spin_enter(&tty_lock);
1751 		ttyflush(tp, FREAD | FWRITE);
1752 		mutex_spin_exit(&tty_lock);
1753 	} else
1754 		ttywflush(tp);
1755 	return (0);
1756 }
1757 
1758 /*
1759  * Handle modem control transition on a tty.
1760  * Flag indicates new state of carrier.
1761  * Returns 0 if the line should be turned off, otherwise 1.
1762  */
1763 int
1764 ttymodem(struct tty *tp, int flag)
1765 {
1766 
1767 	mutex_spin_enter(&tty_lock);
1768 	if (flag == 0) {
1769 		if (ISSET(tp->t_state, TS_CARR_ON)) {
1770 			/*
1771 			 * Lost carrier.
1772 			 */
1773 			CLR(tp->t_state, TS_CARR_ON);
1774 			if (ISSET(tp->t_state, TS_ISOPEN) && !CONNECTED(tp)) {
1775 				ttysig(tp, TTYSIG_LEADER, SIGHUP);
1776 				ttyflush(tp, FREAD | FWRITE);
1777 				mutex_spin_exit(&tty_lock);
1778 				return (0);
1779 			}
1780 		}
1781 	} else {
1782 		if (!ISSET(tp->t_state, TS_CARR_ON)) {
1783 			/*
1784 			 * Carrier now on.
1785 			 */
1786 			SET(tp->t_state, TS_CARR_ON);
1787 			ttwakeup(tp);
1788 		}
1789 	}
1790 	mutex_spin_exit(&tty_lock);
1791 
1792 	return (1);
1793 }
1794 
1795 /*
1796  * Default modem control routine (for other line disciplines).
1797  * Return argument flag, to turn off device on carrier drop.
1798  */
1799 int
1800 nullmodem(struct tty *tp, int flag)
1801 {
1802 
1803 	mutex_spin_enter(&tty_lock);
1804 	if (flag)
1805 		SET(tp->t_state, TS_CARR_ON);
1806 	else {
1807 		CLR(tp->t_state, TS_CARR_ON);
1808 		if (!CONNECTED(tp)) {
1809 			ttysig(tp, TTYSIG_LEADER, SIGHUP);
1810 			mutex_spin_exit(&tty_lock);
1811 			return (0);
1812 		}
1813 	}
1814 	mutex_spin_exit(&tty_lock);
1815 
1816 	return (1);
1817 }
1818 
1819 /*
1820  * Reinput pending characters after state switch.
1821  */
1822 void
1823 ttypend(struct tty *tp)
1824 {
1825 	struct clist	tq;
1826 	int		c;
1827 
1828 	KASSERT(mutex_owned(&tty_lock));
1829 
1830 	CLR(tp->t_lflag, PENDIN);
1831 	SET(tp->t_state, TS_TYPEN);
1832 	tq = tp->t_rawq;
1833 	tp->t_rawq.c_cc = 0;
1834 	tp->t_rawq.c_cf = tp->t_rawq.c_cl = 0;
1835 	while ((c = getc(&tq)) >= 0)
1836 		ttyinput_wlock(c, tp);
1837 	CLR(tp->t_state, TS_TYPEN);
1838 }
1839 
1840 /*
1841  * Process a read call on a tty device.
1842  */
1843 int
1844 ttread(struct tty *tp, struct uio *uio, int flag)
1845 {
1846 	struct clist	*qp;
1847 	u_char		*cc;
1848 	struct proc	*p;
1849 	int		c, first, error, has_stime, last_cc;
1850 	long		lflag, slp;
1851 	struct timeval	now, stime;
1852 
1853 	if (uio->uio_resid == 0)
1854 		return 0;
1855 
1856 	stime.tv_usec = 0;	/* XXX gcc */
1857 	stime.tv_sec = 0;	/* XXX gcc */
1858 
1859 	cc = tp->t_cc;
1860 	p = curproc;
1861 	error = 0;
1862 	has_stime = 0;
1863 	last_cc = 0;
1864 	slp = 0;
1865 
1866  loop:
1867 	mutex_spin_enter(&tty_lock);
1868 	lflag = tp->t_lflag;
1869 	/*
1870 	 * take pending input first
1871 	 */
1872 	if (ISSET(lflag, PENDIN))
1873 		ttypend(tp);
1874 
1875 	/*
1876 	 * Hang process if it's in the background.
1877 	 */
1878 	if (isbackground(p, tp)) {
1879 		if (sigismasked(curlwp, SIGTTIN) ||
1880 		    p->p_lflag & PL_PPWAIT || p->p_pgrp->pg_jobc == 0) {
1881 			mutex_spin_exit(&tty_lock);
1882 			return (EIO);
1883 		}
1884 		mutex_spin_exit(&tty_lock);
1885 
1886 		mutex_enter(&proc_lock);
1887 		pgsignal(p->p_pgrp, SIGTTIN, 1);
1888 		mutex_exit(&proc_lock);
1889 
1890 		mutex_spin_enter(&tty_lock);
1891 		error = ttypause(tp, hz);
1892 		mutex_spin_exit(&tty_lock);
1893 		if (error)
1894 			return (error);
1895 		goto loop;
1896 	}
1897 
1898 	if (!ISSET(lflag, ICANON)) {
1899 		int m = cc[VMIN];
1900 		long t = cc[VTIME];
1901 
1902 		qp = &tp->t_rawq;
1903 		/*
1904 		 * Check each of the four combinations.
1905 		 * (m > 0 && t == 0) is the normal read case.
1906 		 * It should be fairly efficient, so we check that and its
1907 		 * companion case (m == 0 && t == 0) first.
1908 		 * For the other two cases, we compute the target sleep time
1909 		 * into slp.
1910 		 */
1911 		if (t == 0) {
1912 			if (qp->c_cc < m)
1913 				goto sleep;
1914 			goto read;
1915 		}
1916 		t *= hz;		/* time in deca-ticks */
1917 /*
1918  * Time difference in deca-ticks, split division to avoid numeric overflow.
1919  * Ok for hz < ~200kHz
1920  */
1921 #define	diff(t1, t2) (((t1).tv_sec - (t2).tv_sec) * 10 * hz + \
1922 			 ((t1).tv_usec - (t2).tv_usec) / 100 * hz / 1000)
1923 		if (m > 0) {
1924 			if (qp->c_cc <= 0)
1925 				goto sleep;
1926 			if (qp->c_cc >= m)
1927 				goto read;
1928 			if (!has_stime) {
1929 				/* first character, start timer */
1930 				has_stime = 1;
1931 				getmicrotime(&stime);
1932 				slp = t;
1933 			} else if (qp->c_cc > last_cc) {
1934 				/* got a character, restart timer */
1935 				getmicrotime(&stime);
1936 				slp = t;
1937 			} else {
1938 				/* nothing, check expiration */
1939 				getmicrotime(&now);
1940 				slp = t - diff(now, stime);
1941 			}
1942 		} else {	/* m == 0 */
1943 			if (qp->c_cc > 0)
1944 				goto read;
1945 			if (!has_stime) {
1946 				has_stime = 1;
1947 				getmicrotime(&stime);
1948 				slp = t;
1949 			} else {
1950 				getmicrotime(&now);
1951 				slp = t - diff(now, stime);
1952 			}
1953 		}
1954 		last_cc = qp->c_cc;
1955 #undef diff
1956 		if (slp > 0) {
1957 			/*
1958 			 * Convert deca-ticks back to ticks.
1959 			 * Rounding down may make us wake up just short
1960 			 * of the target, so we round up.
1961 			 * Maybe we should do 'slp/10 + 1' because the
1962 			 * first tick maybe almost immediate.
1963 			 * However it is more useful for a program that sets
1964 			 * VTIME=10 to wakeup every second not every 1.01
1965 			 * seconds (if hz=100).
1966 			 */
1967 			slp = (slp + 9)/ 10;
1968 			goto sleep;
1969 		}
1970 	} else if ((qp = &tp->t_canq)->c_cc <= 0) {
1971 		int	carrier;
1972 
1973  sleep:
1974 		/*
1975 		 * If there is no input, sleep on rawq
1976 		 * awaiting hardware receipt and notification.
1977 		 * If we have data, we don't need to check for carrier.
1978 		 */
1979 		carrier = CONNECTED(tp);
1980 		if (!carrier && ISSET(tp->t_state, TS_ISOPEN)) {
1981 			mutex_spin_exit(&tty_lock);
1982 			return (0);	/* EOF */
1983 		}
1984 		if (!has_stime || slp <= 0) {
1985 			if (flag & IO_NDELAY) {
1986 				mutex_spin_exit(&tty_lock);
1987 				return (EWOULDBLOCK);
1988 			}
1989 		}
1990 		error = ttysleep(tp, &tp->t_rawcv, true, slp);
1991 		mutex_spin_exit(&tty_lock);
1992 		/* VMIN == 0: any quantity read satisfies */
1993 		if (cc[VMIN] == 0 && error == EWOULDBLOCK)
1994 			return (0);
1995 		if (error && error != EWOULDBLOCK)
1996 			return (error);
1997 		goto loop;
1998 	}
1999  read:
2000 
2001 	/*
2002 	 * Input present, check for input mapping and processing.
2003 	 */
2004 	first = 1;
2005 	while ((c = getc(qp)) >= 0) {
2006 		/*
2007 		 * delayed suspend (^Y)
2008 		 */
2009 		if (CCEQ(cc[VDSUSP], c) &&
2010 		    ISSET(lflag, IEXTEN|ISIG) == (IEXTEN|ISIG)) {
2011 			ttysig(tp, TTYSIG_PG1, SIGTSTP);
2012 			if (first) {
2013 				error = ttypause(tp, hz);
2014 				if (error)
2015 					break;
2016 				mutex_spin_exit(&tty_lock);
2017 				goto loop;
2018 			}
2019 			break;
2020 		}
2021 		/*
2022 		 * Interpret EOF only in canonical mode.
2023 		 */
2024 		if (CCEQ(cc[VEOF], c) && ISSET(lflag, ICANON))
2025 			break;
2026 		/*
2027 		 * Give user character.
2028 		 */
2029 		mutex_spin_exit(&tty_lock);
2030  		error = ureadc(c, uio);
2031 		mutex_spin_enter(&tty_lock);
2032 		if (error)
2033 			break;
2034  		if (uio->uio_resid == 0)
2035 			break;
2036 		/*
2037 		 * In canonical mode check for a "break character"
2038 		 * marking the end of a "line of input".
2039 		 */
2040 		if (ISSET(lflag, ICANON) && TTBREAKC(c, lflag))
2041 			break;
2042 		first = 0;
2043 	}
2044 
2045 	/*
2046 	 * Look to unblock output now that (presumably)
2047 	 * the input queue has gone down.
2048 	 */
2049 	if (ISSET(tp->t_state, TS_TBLOCK) && tp->t_rawq.c_cc < TTYHOG / 5) {
2050 		if (ISSET(tp->t_iflag, IXOFF) &&
2051 		    cc[VSTART] != _POSIX_VDISABLE &&
2052 		    putc(cc[VSTART], &tp->t_outq) == 0) {
2053 			CLR(tp->t_state, TS_TBLOCK);
2054 			ttstart(tp);
2055 		}
2056 		/* Try to unblock remote output via hardware flow control. */
2057 		if (ISSET(tp->t_cflag, CHWFLOW) && tp->t_hwiflow &&
2058 		    (*tp->t_hwiflow)(tp, 0) != 0)
2059 			CLR(tp->t_state, TS_TBLOCK);
2060 	}
2061 	mutex_spin_exit(&tty_lock);
2062 
2063 	return (error);
2064 }
2065 
2066 /*
2067  * Check the output queue on tp for space for a kernel message (from uprintf
2068  * or tprintf).  Allow some space over the normal hiwater mark so we don't
2069  * lose messages due to normal flow control, but don't let the tty run amok.
2070  * Sleeps here are not interruptible, but we return prematurely if new signals
2071  * arrive.
2072  * Call with tty lock held.
2073  */
2074 static int
2075 ttycheckoutq_wlock(struct tty *tp, int wait)
2076 {
2077 	int	hiwat, error;
2078 
2079 	KASSERT(mutex_owned(&tty_lock));
2080 
2081 	hiwat = tp->t_hiwat;
2082 	if (tp->t_outq.c_cc > hiwat + 200)
2083 		while (tp->t_outq.c_cc > hiwat) {
2084 			ttstart(tp);
2085 			if (wait == 0)
2086 				return (0);
2087 			error = ttysleep(tp, &tp->t_outcv, true, hz);
2088 			if (error == EINTR)
2089 				wait = 0;
2090 		}
2091 
2092 	return (1);
2093 }
2094 
2095 int
2096 ttycheckoutq(struct tty *tp, int wait)
2097 {
2098 	int	r;
2099 
2100 	mutex_spin_enter(&tty_lock);
2101 	r = ttycheckoutq_wlock(tp, wait);
2102 	mutex_spin_exit(&tty_lock);
2103 
2104 	return (r);
2105 }
2106 
2107 /*
2108  * Process a write call on a tty device.
2109  */
2110 int
2111 ttwrite(struct tty *tp, struct uio *uio, int flag)
2112 {
2113 	u_char		*cp;
2114 	struct proc	*p;
2115 	int		cc, ce, i, hiwat, error;
2116 	u_char		obuf[OBUFSIZ];
2117 
2118 	cp = NULL;
2119 	hiwat = tp->t_hiwat;
2120 	error = 0;
2121 	cc = 0;
2122  loop:
2123 	mutex_spin_enter(&tty_lock);
2124 	if (!CONNECTED(tp)) {
2125 		if (ISSET(tp->t_state, TS_ISOPEN)) {
2126 			mutex_spin_exit(&tty_lock);
2127 			return (EIO);
2128 		} else if (flag & IO_NDELAY) {
2129 			mutex_spin_exit(&tty_lock);
2130 			error = EWOULDBLOCK;
2131 			goto out;
2132 		} else {
2133 			/* Sleep awaiting carrier. */
2134 			error = ttysleep(tp, &tp->t_rawcv, true, 0);
2135 			mutex_spin_exit(&tty_lock);
2136 			if (error)
2137 				goto out;
2138 			goto loop;
2139 		}
2140 	}
2141 
2142 	/*
2143 	 * Hang the process if it's in the background.
2144 	 */
2145 	p = curproc;
2146 	if (isbackground(p, tp) &&
2147 	    ISSET(tp->t_lflag, TOSTOP) && (p->p_lflag & PL_PPWAIT) == 0 &&
2148 	    !sigismasked(curlwp, SIGTTOU)) {
2149 		if (p->p_pgrp->pg_jobc == 0) {
2150 			error = EIO;
2151 			mutex_spin_exit(&tty_lock);
2152 			goto out;
2153 		}
2154 		mutex_spin_exit(&tty_lock);
2155 
2156 		mutex_enter(&proc_lock);
2157 		pgsignal(p->p_pgrp, SIGTTOU, 1);
2158 		mutex_exit(&proc_lock);
2159 
2160 		mutex_spin_enter(&tty_lock);
2161 		error = ttypause(tp, hz);
2162 		mutex_spin_exit(&tty_lock);
2163 		if (error)
2164 			goto out;
2165 		goto loop;
2166 	}
2167 	mutex_spin_exit(&tty_lock);
2168 
2169 	/*
2170 	 * Process the user's data in at most OBUFSIZ chunks.  Perform any
2171 	 * output translation.  Keep track of high water mark, sleep on
2172 	 * overflow awaiting device aid in acquiring new space.
2173 	 */
2174 	while (uio->uio_resid > 0 || cc > 0) {
2175 		if (ISSET(tp->t_lflag, FLUSHO)) {
2176 			uio->uio_resid = 0;
2177 			return (0);
2178 		}
2179 		if (tp->t_outq.c_cc > hiwat)
2180 			goto ovhiwat;
2181 		/*
2182 		 * Grab a hunk of data from the user, unless we have some
2183 		 * leftover from last time.
2184 		 */
2185 		if (cc == 0) {
2186 			cc = uimin(uio->uio_resid, OBUFSIZ);
2187 			cp = obuf;
2188 			error = uiomove(cp, cc, uio);
2189 			if (error) {
2190 				cc = 0;
2191 				goto out;
2192 			}
2193 		}
2194 		/*
2195 		 * If nothing fancy need be done, grab those characters we
2196 		 * can handle without any of ttyoutput's processing and
2197 		 * just transfer them to the output q.  For those chars
2198 		 * which require special processing (as indicated by the
2199 		 * bits in char_type), call ttyoutput.  After processing
2200 		 * a hunk of data, look for FLUSHO so ^O's will take effect
2201 		 * immediately.
2202 		 */
2203 		mutex_spin_enter(&tty_lock);
2204 		while (cc > 0) {
2205 			if (!ISSET(tp->t_oflag, OPOST))
2206 				ce = cc;
2207 			else {
2208 				ce = cc - scanc((u_int)cc, cp, char_type,
2209 				    CCLASSMASK);
2210 				/*
2211 				 * If ce is zero, then we're processing
2212 				 * a special character through ttyoutput.
2213 				 */
2214 				if (ce == 0) {
2215 					tp->t_rocount = 0;
2216 					if (ttyoutput(*cp, tp) >= 0) {
2217 						/* out of space */
2218 						mutex_spin_exit(&tty_lock);
2219 						goto overfull;
2220 					}
2221 					cp++;
2222 					cc--;
2223 					if (ISSET(tp->t_lflag, FLUSHO) ||
2224 					    tp->t_outq.c_cc > hiwat) {
2225 						mutex_spin_exit(&tty_lock);
2226 						goto ovhiwat;
2227 					}
2228 					continue;
2229 				}
2230 			}
2231 			/*
2232 			 * A bunch of normal characters have been found.
2233 			 * Transfer them en masse to the output queue and
2234 			 * continue processing at the top of the loop.
2235 			 * If there are any further characters in this
2236 			 * <= OBUFSIZ chunk, the first should be a character
2237 			 * requiring special handling by ttyoutput.
2238 			 */
2239 			tp->t_rocount = 0;
2240 			i = b_to_q(cp, ce, &tp->t_outq);
2241 			ce -= i;
2242 			tp->t_column += ce;
2243 			cp += ce, cc -= ce, tk_nout += ce;
2244 			tp->t_outcc += ce;
2245 			if (i > 0) {
2246 				/* out of space */
2247 				mutex_spin_exit(&tty_lock);
2248 				goto overfull;
2249 			}
2250 			if (ISSET(tp->t_lflag, FLUSHO) ||
2251 			    tp->t_outq.c_cc > hiwat)
2252 				break;
2253 		}
2254 		ttstart(tp);
2255 		mutex_spin_exit(&tty_lock);
2256 	}
2257 
2258  out:
2259 	/*
2260 	 * If cc is nonzero, we leave the uio structure inconsistent, as the
2261 	 * offset and iov pointers have moved forward, but it doesn't matter
2262 	 * (the call will either return short or restart with a new uio).
2263 	 */
2264 	uio->uio_resid += cc;
2265 	return (error);
2266 
2267  overfull:
2268 	/*
2269 	 * Since we are using ring buffers, if we can't insert any more into
2270 	 * the output queue, we can assume the ring is full and that someone
2271 	 * forgot to set the high water mark correctly.  We set it and then
2272 	 * proceed as normal.
2273 	 */
2274 	hiwat = tp->t_outq.c_cc - 1;
2275 
2276  ovhiwat:
2277 	mutex_spin_enter(&tty_lock);
2278 	ttstart(tp);
2279 	/*
2280 	 * This can only occur if FLUSHO is set in t_lflag,
2281 	 * or if ttstart/oproc is synchronous (or very fast).
2282 	 */
2283 	if (tp->t_outq.c_cc <= hiwat) {
2284 		mutex_spin_exit(&tty_lock);
2285 		goto loop;
2286 	}
2287 	if (flag & IO_NDELAY) {
2288 		mutex_spin_exit(&tty_lock);
2289 		error = EWOULDBLOCK;
2290 		goto out;
2291 	}
2292 	error = ttysleep(tp, &tp->t_outcv, true, 0);
2293 	mutex_spin_exit(&tty_lock);
2294 	if (error)
2295 		goto out;
2296 	goto loop;
2297 }
2298 
2299 /*
2300  * Try to pull more output from the producer.  Return non-zero if
2301  * there is output ready to be sent.
2302  */
2303 bool
2304 ttypull(struct tty *tp)
2305 {
2306 
2307 	/* XXXSMP not yet KASSERT(mutex_owned(&tty_lock)); */
2308 
2309 	if (tp->t_outq.c_cc <= tp->t_lowat) {
2310 		cv_broadcast(&tp->t_outcv);
2311 		selnotify(&tp->t_wsel, 0, NOTE_SUBMIT);
2312 	}
2313 	return tp->t_outq.c_cc != 0;
2314 }
2315 
2316 /*
2317  * Rubout one character from the rawq of tp
2318  * as cleanly as possible.
2319  * Called with tty lock held.
2320  */
2321 void
2322 ttyrub(int c, struct tty *tp)
2323 {
2324 	u_char	*cp;
2325 	int	savecol, tabc;
2326 
2327 	KASSERT(mutex_owned(&tty_lock));
2328 
2329 	if (!ISSET(tp->t_lflag, ECHO) || ISSET(tp->t_lflag, EXTPROC))
2330 		return;
2331 	CLR(tp->t_lflag, FLUSHO);
2332 	if (ISSET(tp->t_lflag, ECHOE)) {
2333 		if (tp->t_rocount == 0) {
2334 			/*
2335 			 * Screwed by ttwrite; retype
2336 			 */
2337 			ttyretype(tp);
2338 			return;
2339 		}
2340 		if (c == ('\t' | TTY_QUOTE) || c == ('\n' | TTY_QUOTE))
2341 			ttyrubo(tp, 2);
2342 		else {
2343 			CLR(c, ~TTY_CHARMASK);
2344 			switch (CCLASS(c)) {
2345 			case ORDINARY:
2346 				ttyrubo(tp, 1);
2347 				break;
2348 			case BACKSPACE:
2349 			case CONTROL:
2350 			case NEWLINE:
2351 			case RETURN:
2352 			case VTAB:
2353 				if (ISSET(tp->t_lflag, ECHOCTL))
2354 					ttyrubo(tp, 2);
2355 				break;
2356 			case TAB:
2357 				if (tp->t_rocount < tp->t_rawq.c_cc) {
2358 					ttyretype(tp);
2359 					return;
2360 				}
2361 				savecol = tp->t_column;
2362 				SET(tp->t_state, TS_CNTTB);
2363 				SET(tp->t_lflag, FLUSHO);
2364 				tp->t_column = tp->t_rocol;
2365 				for (cp = firstc(&tp->t_rawq, &tabc); cp;
2366 				    cp = nextc(&tp->t_rawq, cp, &tabc))
2367 					ttyecho(tabc, tp);
2368 				CLR(tp->t_lflag, FLUSHO);
2369 				CLR(tp->t_state, TS_CNTTB);
2370 
2371 				/* savecol will now be length of the tab. */
2372 				savecol -= tp->t_column;
2373 				tp->t_column += savecol;
2374 				if (savecol > 8)
2375 					savecol = 8;	/* overflow screw */
2376 				while (--savecol >= 0)
2377 					(void)ttyoutput('\b', tp);
2378 				break;
2379 			default:			/* XXX */
2380 				(void)printf("ttyrub: would panic c = %d, "
2381 				    "val = %d\n", c, CCLASS(c));
2382 			}
2383 		}
2384 	} else if (ISSET(tp->t_lflag, ECHOPRT)) {
2385 		if (!ISSET(tp->t_state, TS_ERASE)) {
2386 			SET(tp->t_state, TS_ERASE);
2387 			(void)ttyoutput('\\', tp);
2388 		}
2389 		ttyecho(c, tp);
2390 	} else
2391 		ttyecho(tp->t_cc[VERASE], tp);
2392 	--tp->t_rocount;
2393 }
2394 
2395 /*
2396  * Back over cnt characters, erasing them.
2397  * Called with tty lock held.
2398  */
2399 static void
2400 ttyrubo(struct tty *tp, int cnt)
2401 {
2402 
2403 	KASSERT(mutex_owned(&tty_lock));
2404 
2405 	while (cnt-- > 0) {
2406 		(void)ttyoutput('\b', tp);
2407 		(void)ttyoutput(' ', tp);
2408 		(void)ttyoutput('\b', tp);
2409 	}
2410 }
2411 
2412 /*
2413  * ttyretype --
2414  *	Reprint the rawq line.  Note, it is assumed that c_cc has already
2415  *	been checked.
2416  *
2417  * Called with tty lock held.
2418  */
2419 void
2420 ttyretype(struct tty *tp)
2421 {
2422 	u_char	*cp;
2423 	int	c;
2424 
2425 	KASSERT(mutex_owned(&tty_lock));
2426 
2427 	/* Echo the reprint character. */
2428 	if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
2429 		ttyecho(tp->t_cc[VREPRINT], tp);
2430 
2431 	(void)ttyoutput('\n', tp);
2432 
2433 	for (cp = firstc(&tp->t_canq, &c); cp; cp = nextc(&tp->t_canq, cp, &c))
2434 		ttyecho(c, tp);
2435 	for (cp = firstc(&tp->t_rawq, &c); cp; cp = nextc(&tp->t_rawq, cp, &c))
2436 		ttyecho(c, tp);
2437 	CLR(tp->t_state, TS_ERASE);
2438 
2439 	tp->t_rocount = tp->t_rawq.c_cc;
2440 	tp->t_rocol = 0;
2441 }
2442 
2443 /*
2444  * Echo a typed character to the terminal.
2445  * Called with tty lock held.
2446  */
2447 static void
2448 ttyecho(int c, struct tty *tp)
2449 {
2450 
2451 	KASSERT(mutex_owned(&tty_lock));
2452 
2453 	if (!ISSET(tp->t_state, TS_CNTTB))
2454 		CLR(tp->t_lflag, FLUSHO);
2455 	if ((!ISSET(tp->t_lflag, ECHO) &&
2456 	    (!ISSET(tp->t_lflag, ECHONL) || c != '\n')) ||
2457 	    ISSET(tp->t_lflag, EXTPROC))
2458 		return;
2459 	if (((ISSET(tp->t_lflag, ECHOCTL) &&
2460 	    (ISSET(c, TTY_CHARMASK) <= 037 && c != '\t' && c != '\n')) ||
2461 	    ISSET(c, TTY_CHARMASK) == 0177)) {
2462 		(void)ttyoutput('^', tp);
2463 		CLR(c, ~TTY_CHARMASK);
2464 		if (c == 0177)
2465 			c = '?';
2466 		else
2467 			c += 'A' - 1;
2468 	}
2469 	(void)ttyoutput(c, tp);
2470 }
2471 
2472 /*
2473  * Wake up any readers on a tty.
2474  * Called with tty lock held.
2475  */
2476 void
2477 ttwakeup(struct tty *tp)
2478 {
2479 
2480 	KASSERT(mutex_owned(&tty_lock));
2481 
2482 	selnotify(&tp->t_rsel, 0, NOTE_SUBMIT);
2483 	if (ISSET(tp->t_state, TS_ASYNC))
2484 		ttysig(tp, TTYSIG_PG2, SIGIO);
2485 	cv_broadcast(&tp->t_rawcv);
2486 }
2487 
2488 /*
2489  * Look up a code for a specified speed in a conversion table;
2490  * used by drivers to map software speed values to hardware parameters.
2491  */
2492 int
2493 ttspeedtab(int speed, const struct speedtab *table)
2494 {
2495 
2496 	for (; table->sp_speed != -1; table++)
2497 		if (table->sp_speed == speed)
2498 			return (table->sp_code);
2499 	return (-1);
2500 }
2501 
2502 /*
2503  * Set tty hi and low water marks.
2504  *
2505  * Try to arrange the dynamics so there's about one second
2506  * from hi to low water.
2507  */
2508 void
2509 ttsetwater(struct tty *tp)
2510 {
2511 	int	cps, x;
2512 
2513 	/* XXX not yet KASSERT(mutex_owned(&tty_lock)); */
2514 
2515 #define	CLAMP(x, h, l)	((x) > h ? h : ((x) < l) ? l : (x))
2516 
2517 	cps = tp->t_ospeed / 10;
2518 	tp->t_lowat = x = CLAMP(cps / 2, TTMAXLOWAT, TTMINLOWAT);
2519 	x += cps;
2520 	x = CLAMP(x, TTMAXHIWAT, TTMINHIWAT);
2521 	tp->t_hiwat = roundup(x, TTROUND);
2522 #undef	CLAMP
2523 }
2524 
2525 /*
2526  * Prepare report on state of foreground process group.
2527  * Call with &proc_lock held.
2528  */
2529 void
2530 ttygetinfo(struct tty *tp, int fromsig, char *buf, size_t bufsz)
2531 {
2532 	struct lwp	*l;
2533 	struct proc	*p, *pick = NULL;
2534 	struct timeval	utime, stime;
2535 	int		tmp;
2536 	fixpt_t		pctcpu = 0;
2537 	const char	*msg = NULL;
2538 	char		lmsg[100];
2539 	long		rss;
2540 	bool		again = false;
2541 
2542 	KASSERT(mutex_owned(&proc_lock));
2543 
2544 	*buf = '\0';
2545 
2546  retry:
2547 	if (tp->t_session == NULL)
2548 		msg = "not a controlling terminal\n";
2549 	else if (tp->t_pgrp == NULL)
2550 		msg = "no foreground process group\n";
2551 	else if ((p = LIST_FIRST(&tp->t_pgrp->pg_members)) == NULL)
2552 		msg = "empty foreground process group\n";
2553 	else {
2554 		/* Pick interesting process. */
2555 		for (; p != NULL; p = LIST_NEXT(p, p_pglist)) {
2556 			struct proc *oldpick;
2557 
2558 			if (pick == NULL) {
2559 				pick = p;
2560 				continue;
2561 			}
2562 			if (pick->p_lock < p->p_lock) {
2563 				mutex_enter(pick->p_lock);
2564 				mutex_enter(p->p_lock);
2565 			} else if (pick->p_lock > p->p_lock) {
2566 				mutex_enter(p->p_lock);
2567 				mutex_enter(pick->p_lock);
2568 			} else
2569 				mutex_enter(p->p_lock);
2570 			oldpick = pick;
2571 			if (proc_compare_wrapper(pick, p))
2572 				pick = p;
2573 			mutex_exit(p->p_lock);
2574 			if (p->p_lock != oldpick->p_lock)
2575 				mutex_exit(oldpick->p_lock);
2576 		}
2577 
2578 		if (pick != NULL) {
2579 			mutex_enter(pick->p_lock);
2580 			if (P_ZOMBIE(pick)) {
2581 				mutex_exit(pick->p_lock);
2582 				pick = NULL;
2583 				if (!again) {
2584 					again = true;
2585 					goto retry;
2586 				}
2587 				msg = "found only zombie processes\n";
2588 			}
2589 			if (pick && fromsig &&
2590 			    (SIGACTION_PS(pick->p_sigacts, SIGINFO).sa_flags &
2591 			    SA_NOKERNINFO)) {
2592 				mutex_exit(pick->p_lock);
2593 				return;
2594 			}
2595 		}
2596 	}
2597 
2598 	/* Print load average. */
2599 	tmp = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
2600 	snprintf(lmsg, sizeof(lmsg), "load: %d.%02d ", tmp / 100, tmp % 100);
2601 	strlcat(buf, lmsg, bufsz);
2602 
2603 	if (pick == NULL) {
2604 		strlcat(buf, msg, bufsz);
2605 		return;
2606 	}
2607 
2608 	snprintf(lmsg, sizeof(lmsg), " cmd: %s %d [", pick->p_comm,
2609 	    pick->p_pid);
2610 	strlcat(buf, lmsg, bufsz);
2611 
2612 	KASSERT(mutex_owned(pick->p_lock));
2613 	LIST_FOREACH(l, &pick->p_lwps, l_sibling) {
2614 		const char *lp;
2615 		lwp_lock(l);
2616 #ifdef LWP_PC
2617 #define FMT_RUN "%#"PRIxVADDR
2618 #define VAL_RUNNING (vaddr_t)LWP_PC(l)
2619 #define VAL_RUNABLE (vaddr_t)LWP_PC(l)
2620 #else
2621 #define FMT_RUN "%s"
2622 #define VAL_RUNNING "running"
2623 #define VAL_RUNABLE "runnable"
2624 #endif
2625 		switch (l->l_stat) {
2626 		case LSONPROC:
2627 			snprintf(lmsg, sizeof(lmsg), FMT_RUN"/%d", VAL_RUNNING,
2628 			    cpu_index(l->l_cpu));
2629 			lp = lmsg;
2630 			break;
2631 		case LSRUN:
2632 			snprintf(lmsg, sizeof(lmsg), FMT_RUN, VAL_RUNABLE);
2633 			lp = lmsg;
2634 			break;
2635 		default:
2636 			lp = l->l_wchan ? l->l_wmesg : "iowait";
2637 			break;
2638 		}
2639 		strlcat(buf, lp, bufsz);
2640 		strlcat(buf, LIST_NEXT(l, l_sibling) != NULL ? " " : "] ",
2641 		    bufsz);
2642 		pctcpu += l->l_pctcpu;
2643 		lwp_unlock(l);
2644 	}
2645 	pctcpu += pick->p_pctcpu;
2646 	calcru(pick, &utime, &stime, NULL, NULL);
2647 	mutex_exit(pick->p_lock);
2648 
2649 	/* Round up and print user+system time, %CPU and RSS. */
2650 	utime.tv_usec += 5000;
2651 	if (utime.tv_usec >= 1000000) {
2652 		utime.tv_sec += 1;
2653 		utime.tv_usec -= 1000000;
2654 	}
2655 	stime.tv_usec += 5000;
2656 	if (stime.tv_usec >= 1000000) {
2657 		stime.tv_sec += 1;
2658 		stime.tv_usec -= 1000000;
2659 	}
2660 #define	pgtok(a)	(((u_long) ((a) * PAGE_SIZE) / 1024))
2661 	tmp = (pctcpu * 10000 + FSCALE / 2) >> FSHIFT;
2662 	if (pick->p_stat == SIDL || P_ZOMBIE(pick))
2663 		rss = 0;
2664 	else
2665 		rss = pgtok(vm_resident_count(pick->p_vmspace));
2666 
2667 	snprintf(lmsg, sizeof(lmsg), "%ld.%02ldu %ld.%02lds %d%% %ldk",
2668 	    (long)utime.tv_sec, (long)utime.tv_usec / 10000,
2669 	    (long)stime.tv_sec, (long)stime.tv_usec / 10000,
2670 	    tmp / 100, rss);
2671 	strlcat(buf, lmsg, bufsz);
2672 }
2673 
2674 /*
2675  * Print report on state of foreground process group.
2676  * Call with tty_lock held.
2677  */
2678 void
2679 ttyputinfo(struct tty *tp, char *buf)
2680 {
2681 
2682 	KASSERT(mutex_owned(&tty_lock));
2683 
2684 	if (ttycheckoutq_wlock(tp, 0) == 0)
2685 		return;
2686 	ttyprintf_nolock(tp, "%s\n", buf);
2687 	tp->t_rocount = 0;	/* so pending input will be retyped if BS */
2688 }
2689 
2690 /*
2691  * Returns 1 if p2 has a better chance being the active foreground process
2692  * in a terminal instead of p1.
2693  */
2694 static int
2695 proc_compare_wrapper(struct proc *p1, struct proc *p2)
2696 {
2697 	lwp_t *l1, *l2;
2698 
2699 	KASSERT(mutex_owned(p1->p_lock));
2700 	KASSERT(mutex_owned(p2->p_lock));
2701 
2702 	l1 = LIST_FIRST(&p1->p_lwps);
2703 	l2 = LIST_FIRST(&p2->p_lwps);
2704 
2705 	return proc_compare(p1, l1, p2, l2);
2706 }
2707 
2708 /*
2709  * Output char to tty; console putchar style.
2710  * Can be called with tty lock held through kprintf() machinery..
2711  */
2712 int
2713 tputchar(int c, int flags, struct tty *tp)
2714 {
2715 	int r = 0;
2716 
2717 	if ((flags & NOLOCK) == 0)
2718 		mutex_spin_enter(&tty_lock);
2719 	if (!CONNECTED(tp)) {
2720 		r = -1;
2721 		goto out;
2722 	}
2723 	if (c == '\n')
2724 		(void)ttyoutput('\r', tp);
2725 	(void)ttyoutput(c, tp);
2726 	ttstart(tp);
2727 out:
2728 	if ((flags & NOLOCK) == 0)
2729 		mutex_spin_exit(&tty_lock);
2730 	return (r);
2731 }
2732 
2733 /*
2734  * Sleep on chan, returning ERESTART if tty changed while we napped and
2735  * returning any errors (e.g. EINTR/EWOULDBLOCK) reported by
2736  * cv_timedwait(_sig).
2737  * If the tty is revoked, restarting a pending call will redo validation done
2738  * at the start of the call.
2739  *
2740  * Must be called with the tty lock held.
2741  */
2742 int
2743 ttysleep(struct tty *tp, kcondvar_t *cv, bool catch_p, int timo)
2744 {
2745 	int	error;
2746 	short	gen;
2747 
2748 	KASSERT(mutex_owned(&tty_lock));
2749 
2750 	gen = tp->t_gen;
2751 	if (cv == NULL)
2752 		error = kpause("ttypause", catch_p, timo, &tty_lock);
2753 	else if (catch_p)
2754 		error = cv_timedwait_sig(cv, &tty_lock, timo);
2755 	else
2756 		error = cv_timedwait(cv, &tty_lock, timo);
2757 	if (error != 0)
2758 		return (error);
2759 	return (tp->t_gen == gen ? 0 : ERESTART);
2760 }
2761 
2762 int
2763 ttypause(struct tty *tp, int timo)
2764 {
2765 	int error;
2766 
2767 	error = ttysleep(tp, NULL, true, timo);
2768 	if (error == EWOULDBLOCK)
2769 		error = 0;
2770 	return error;
2771 }
2772 
2773 /*
2774  * Attach a tty to the tty list.
2775  *
2776  * This should be called ONLY once per real tty (including pty's).
2777  * eg, on the sparc, the keyboard and mouse have struct tty's that are
2778  * distinctly NOT usable as tty's, and thus should not be attached to
2779  * the ttylist.  This is why this call is not done from tty_alloc().
2780  *
2781  * Device drivers should attach tty's at a similar time that they are
2782  * allocated, or, for the case of statically allocated struct tty's
2783  * either in the attach or (first) open routine.
2784  */
2785 void
2786 tty_attach(struct tty *tp)
2787 {
2788 
2789 	mutex_spin_enter(&tty_lock);
2790 	TAILQ_INSERT_TAIL(&ttylist, tp, tty_link);
2791 	++tty_count;
2792 	mutex_spin_exit(&tty_lock);
2793 }
2794 
2795 /*
2796  * Remove a tty from the tty list.
2797  */
2798 void
2799 tty_detach(struct tty *tp)
2800 {
2801 
2802 	mutex_spin_enter(&tty_lock);
2803 	--tty_count;
2804 #ifdef DIAGNOSTIC
2805 	if (tty_count < 0)
2806 		panic("tty_detach: tty_count < 0");
2807 #endif
2808 	TAILQ_REMOVE(&ttylist, tp, tty_link);
2809 	mutex_spin_exit(&tty_lock);
2810 }
2811 
2812 /*
2813  * Allocate a tty structure and its associated buffers.
2814  */
2815 struct tty *
2816 tty_alloc(void)
2817 {
2818 	struct tty *tp;
2819 	int i;
2820 
2821 	tp = kmem_zalloc(sizeof(*tp), KM_SLEEP);
2822 	callout_init(&tp->t_rstrt_ch, 0);
2823 	callout_setfunc(&tp->t_rstrt_ch, ttrstrt, tp);
2824 	tp->t_qsize = tty_qsize;
2825 	clalloc(&tp->t_rawq, tp->t_qsize, 1);
2826 	cv_init(&tp->t_rawcv, "ttyraw");
2827 	cv_init(&tp->t_rawcvf, "ttyrawf");
2828 	clalloc(&tp->t_canq, tp->t_qsize, 1);
2829 	cv_init(&tp->t_cancv, "ttycan");
2830 	cv_init(&tp->t_cancvf, "ttycanf");
2831 	/* output queue doesn't need quoting */
2832 	clalloc(&tp->t_outq, tp->t_qsize, 0);
2833 	cv_init(&tp->t_outcv, "ttyout");
2834 	cv_init(&tp->t_outcvf, "ttyoutf");
2835 	/* Set default line discipline. */
2836 	tp->t_linesw = ttyldisc_default();
2837 	tp->t_dev = NODEV;
2838 	selinit(&tp->t_rsel);
2839 	selinit(&tp->t_wsel);
2840 	for (i = 0; i < TTYSIG_COUNT; i++)  {
2841 		sigemptyset(&tp->t_sigs[i]);
2842 	}
2843 
2844 	return tp;
2845 }
2846 
2847 /*
2848  * Free a tty structure and its buffers.
2849  *
2850  * Be sure to call tty_detach() for any tty that has been
2851  * tty_attach()ed.
2852  */
2853 void
2854 tty_free(struct tty *tp)
2855 {
2856 	int i;
2857 
2858 	mutex_enter(&proc_lock);
2859 	mutex_enter(&tty_lock);
2860 	for (i = 0; i < TTYSIG_COUNT; i++)
2861 		sigemptyset(&tp->t_sigs[i]);
2862 	if (tp->t_sigcount != 0)
2863 		TAILQ_REMOVE(&tty_sigqueue, tp, t_sigqueue);
2864 	mutex_exit(&tty_lock);
2865 	mutex_exit(&proc_lock);
2866 
2867 	callout_halt(&tp->t_rstrt_ch, NULL);
2868 	callout_destroy(&tp->t_rstrt_ch);
2869 	ttyldisc_release(tp->t_linesw);
2870 	clfree(&tp->t_rawq);
2871 	clfree(&tp->t_canq);
2872 	clfree(&tp->t_outq);
2873 	cv_destroy(&tp->t_rawcv);
2874 	cv_destroy(&tp->t_rawcvf);
2875 	cv_destroy(&tp->t_cancv);
2876 	cv_destroy(&tp->t_cancvf);
2877 	cv_destroy(&tp->t_outcv);
2878 	cv_destroy(&tp->t_outcvf);
2879 	seldestroy(&tp->t_rsel);
2880 	seldestroy(&tp->t_wsel);
2881 	kmem_free(tp, sizeof(*tp));
2882 }
2883 
2884 /*
2885  * ttyprintf_nolock: send a message to a specific tty, without locking.
2886  *
2887  * => should be used only by tty driver or anything that knows the
2888  *    underlying tty will not be revoked(2)'d away.  [otherwise,
2889  *    use tprintf]
2890  */
2891 static void
2892 ttyprintf_nolock(struct tty *tp, const char *fmt, ...)
2893 {
2894 	va_list ap;
2895 
2896 	/* No mutex needed; going to process TTY. */
2897 	va_start(ap, fmt);
2898 	kprintf(fmt, TOTTY|NOLOCK, tp, NULL, ap);
2899 	va_end(ap);
2900 }
2901 
2902 static int
2903 tty_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
2904     void *arg0, void *arg1, void *arg2, void *arg3)
2905 {
2906 	struct tty *tty;
2907 	int result;
2908 
2909 	result = KAUTH_RESULT_DEFER;
2910 
2911 	if (action != KAUTH_DEVICE_TTY_OPEN)
2912 		return result;
2913 
2914 	tty = arg0;
2915 
2916 	/* If it's not opened, we allow. */
2917 	if ((tty->t_state & TS_ISOPEN) == 0)
2918 		result = KAUTH_RESULT_ALLOW;
2919 	else {
2920 		/*
2921 		 * If it's opened, we can only allow if it's not exclusively
2922 		 * opened; otherwise, that's a privileged operation and we
2923 		 * let the secmodel handle it.
2924 		 */
2925 		if ((tty->t_state & TS_XCLUDE) == 0)
2926 			result = KAUTH_RESULT_ALLOW;
2927 	}
2928 
2929 	return result;
2930 }
2931 
2932 /*
2933  * Initialize the tty subsystem.
2934  */
2935 void
2936 tty_init(void)
2937 {
2938 
2939 	mutex_init(&tty_lock, MUTEX_DEFAULT, IPL_VM);
2940 	tty_sigsih = softint_establish(SOFTINT_CLOCK, ttysigintr, NULL);
2941 	KASSERT(tty_sigsih != NULL);
2942 
2943 	tty_listener = kauth_listen_scope(KAUTH_SCOPE_DEVICE,
2944 	    tty_listener_cb, NULL);
2945 
2946 	sysctl_kern_tty_setup();
2947 }
2948 
2949 /*
2950  * Send a signal from a tty to its process group or session leader.
2951  * Handoff to the target is deferred to a soft interrupt.
2952  */
2953 void
2954 ttysig(struct tty *tp, enum ttysigtype st, int sig)
2955 {
2956 	sigset_t *sp;
2957 
2958 	/* XXXSMP not yet KASSERT(mutex_owned(&tty_lock)); */
2959 
2960 	sp = &tp->t_sigs[st];
2961 	if (sigismember(sp, sig))
2962 		return;
2963 	sigaddset(sp, sig);
2964 	if (tp->t_sigcount++ == 0)
2965 		TAILQ_INSERT_TAIL(&tty_sigqueue, tp, t_sigqueue);
2966 	softint_schedule(tty_sigsih);
2967 }
2968 
2969 /*
2970  * Deliver deferred signals from ttys.  Note that the process groups
2971  * and sessions associated with the ttys may have changed from when
2972  * the signal was originally sent, but in practice it should not matter.
2973  * For signals produced as a result of a syscall, the soft interrupt
2974  * will fire before the syscall returns to the user.
2975  */
2976 static void
2977 ttysigintr(void *cookie)
2978 {
2979 	struct tty *tp;
2980 	enum ttysigtype st;
2981 	struct pgrp *pgrp;
2982 	struct session *sess;
2983 	int sig, lflag;
2984 	char infobuf[200];
2985 
2986 	mutex_enter(&proc_lock);
2987 	mutex_spin_enter(&tty_lock);
2988 	while ((tp = TAILQ_FIRST(&tty_sigqueue)) != NULL) {
2989 		KASSERT(tp->t_sigcount > 0);
2990 		for (st = TTYSIG_PG1; st < TTYSIG_COUNT; st++) {
2991 			if ((sig = firstsig(&tp->t_sigs[st])) != 0)
2992 				break;
2993 		}
2994 		KASSERT(st < TTYSIG_COUNT);
2995 		sigdelset(&tp->t_sigs[st], sig);
2996 		if (--tp->t_sigcount == 0)
2997 			TAILQ_REMOVE(&tty_sigqueue, tp, t_sigqueue);
2998 		pgrp = tp->t_pgrp;
2999 		sess = tp->t_session;
3000 		lflag = tp->t_lflag;
3001 		if (sig == SIGINFO) {
3002 			if (ISSET(tp->t_state, TS_SIGINFO)) {
3003 				/* Via ioctl: ignore tty option. */
3004 				tp->t_state &= ~TS_SIGINFO;
3005 				lflag |= ISIG;
3006 			}
3007 			if (!ISSET(lflag, NOKERNINFO)) {
3008 				mutex_spin_exit(&tty_lock);
3009 				ttygetinfo(tp, 1, infobuf, sizeof(infobuf));
3010 				mutex_spin_enter(&tty_lock);
3011 				ttyputinfo(tp, infobuf);
3012 			}
3013 			if (!ISSET(lflag, ISIG))
3014 				continue;
3015 		}
3016 		mutex_spin_exit(&tty_lock);
3017 		KASSERT(sig != 0);
3018 		switch (st) {
3019 		case TTYSIG_PG1:
3020 			if (pgrp != NULL)
3021 				pgsignal(pgrp, sig, 1);
3022 			break;
3023 		case TTYSIG_PG2:
3024 			if (pgrp != NULL)
3025 				pgsignal(pgrp, sig, sess != NULL);
3026 			break;
3027 		case TTYSIG_LEADER:
3028 			if (sess != NULL && sess->s_leader != NULL)
3029 				psignal(sess->s_leader, sig);
3030 			break;
3031 		default:
3032 			/* NOTREACHED */
3033 			break;
3034 		}
3035 		mutex_spin_enter(&tty_lock);
3036 	}
3037 	mutex_spin_exit(&tty_lock);
3038 	mutex_exit(&proc_lock);
3039 }
3040 
3041 unsigned char
3042 tty_getctrlchar(struct tty *tp, unsigned which)
3043 {
3044 	KASSERT(which < NCCS);
3045 	return tp->t_cc[which];
3046 }
3047 
3048 void
3049 tty_setctrlchar(struct tty *tp, unsigned which, unsigned char val)
3050 {
3051 	KASSERT(which < NCCS);
3052 	tp->t_cc[which] = val;
3053 }
3054 
3055 int
3056 tty_try_xonxoff(struct tty *tp, unsigned char c)
3057 {
3058     const struct cdevsw *cdev;
3059 
3060     if (tp->t_iflag & IXON) {
3061 	if (c == tp->t_cc[VSTOP] && tp->t_cc[VSTOP] != _POSIX_VDISABLE) {
3062 	    if ((tp->t_state & TS_TTSTOP) == 0) {
3063 		tp->t_state |= TS_TTSTOP;
3064 		cdev = cdevsw_lookup(tp->t_dev);
3065 		if (cdev != NULL)
3066 			(*cdev->d_stop)(tp, 0);
3067 	    }
3068 	    return 0;
3069 	}
3070 	if (c == tp->t_cc[VSTART] && tp->t_cc[VSTART] != _POSIX_VDISABLE) {
3071 	    tp->t_state &= ~TS_TTSTOP;
3072 	    if (tp->t_oproc != NULL) {
3073 	        mutex_spin_enter(&tty_lock);	/* XXX */
3074 		(*tp->t_oproc)(tp);
3075 	        mutex_spin_exit(&tty_lock);	/* XXX */
3076 	    }
3077 	    return 0;
3078 	}
3079     }
3080     return EAGAIN;
3081 }
3082