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kernel - kqueue - refactor kqueue_scan(), rename tick to ustick
[dragonfly.git] / sys / kern / tty.c
blob197928934d6f2667b0245c84fc43686a3206857a
1 /*-
2 * Copyright (c) 1982, 1986, 1990, 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)tty.c 8.8 (Berkeley) 1/21/94
39 * $FreeBSD: src/sys/kern/tty.c,v 1.129.2.5 2002/03/11 01:32:31 dd Exp $
40 * $DragonFly: src/sys/kern/tty.c,v 1.46 2008/09/10 09:50:09 y0netan1 Exp $
41 */
42
43 /*-
44 * TODO:
45 * o Fix races for sending the start char in ttyflush().
46 * o Handle inter-byte timeout for "MIN > 0, TIME > 0" in ttyselect().
47 * With luck, there will be MIN chars before select() returns().
48 * o Handle CLOCAL consistently for ptys. Perhaps disallow setting it.
49 * o Don't allow input in TS_ZOMBIE case. It would be visible through
50 * FIONREAD.
51 * o Do the new sio locking stuff here and use it to avoid special
52 * case for EXTPROC?
53 * o Lock PENDIN too?
54 * o Move EXTPROC and/or PENDIN to t_state?
55 * o Wrap most of ttioctl in spltty/splx.
56 * o Implement TIOCNOTTY or remove it from <sys/ioctl.h>.
57 * o Send STOP if IXOFF is toggled off while TS_TBLOCK is set.
58 * o Don't allow certain termios flags to affect disciplines other
59 * than TTYDISC. Cancel their effects before switch disciplines
60 * and ignore them if they are set while we are in another
61 * discipline.
62 * o Now that historical speed conversions are handled here, don't
63 * do them in drivers.
64 * o Check for TS_CARR_ON being set while everything is closed and not
65 * waiting for carrier. TS_CARR_ON isn't cleared if nothing is open,
66 * so it would live until the next open even if carrier drops.
67 * o Restore TS_WOPEN since it is useful in pstat. It must be cleared
68 * only when _all_ openers leave open().
69 */
70
71 #include "opt_compat.h"
72 #include "opt_uconsole.h"
73
74 #include <sys/param.h>
75 #include <sys/systm.h>
76 #include <sys/filio.h>
77 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
78 #include <sys/ioctl_compat.h>
79 #endif
80 #include <sys/proc.h>
81 #include <sys/priv.h>
82 #define TTYDEFCHARS
83 #include <sys/tty.h>
84 #include <sys/clist.h>
85 #undef TTYDEFCHARS
86 #include <sys/fcntl.h>
87 #include <sys/conf.h>
88 #include <sys/dkstat.h>
89 #include <sys/poll.h>
90 #include <sys/kernel.h>
91 #include <sys/vnode.h>
92 #include <sys/signalvar.h>
93 #include <sys/signal2.h>
94 #include <sys/resourcevar.h>
95 #include <sys/malloc.h>
96 #include <sys/filedesc.h>
97 #include <sys/sysctl.h>
98 #include <sys/thread2.h>
99
100 #include <vm/vm.h>
101 #include <sys/lock.h>
102 #include <vm/pmap.h>
103 #include <vm/vm_map.h>
104
105 MALLOC_DEFINE(M_TTYS, "ttys", "tty data structures");
106
107 static int proc_compare (struct proc *p1, struct proc *p2);
108 static int ttnread (struct tty *tp);
109 static void ttyecho (int c, struct tty *tp);
110 static int ttyoutput (int c, struct tty *tp);
111 static void ttypend (struct tty *tp);
112 static void ttyretype (struct tty *tp);
113 static void ttyrub (int c, struct tty *tp);
114 static void ttyrubo (struct tty *tp, int cnt);
115 static void ttyunblock (struct tty *tp);
116 static int ttywflush (struct tty *tp);
117 static int filt_ttyread (struct knote *kn, long hint);
118 static void filt_ttyrdetach (struct knote *kn);
119 static int filt_ttywrite (struct knote *kn, long hint);
120 static void filt_ttywdetach (struct knote *kn);
121
122 /*
123 * Table with character classes and parity. The 8th bit indicates parity,
124 * the 7th bit indicates the character is an alphameric or underscore (for
125 * ALTWERASE), and the low 6 bits indicate delay type. If the low 6 bits
126 * are 0 then the character needs no special processing on output; classes
127 * other than 0 might be translated or (not currently) require delays.
128 */
129 #define E 0x00 /* Even parity. */
130 #define O 0x80 /* Odd parity. */
131 #define PARITY(c) (char_type[c] & O)
132
133 #define ALPHA 0x40 /* Alpha or underscore. */
134 #define ISALPHA(c) (char_type[(c) & TTY_CHARMASK] & ALPHA)
135
136 #define CCLASSMASK 0x3f
137 #define CCLASS(c) (char_type[c] & CCLASSMASK)
138
139 #define BS BACKSPACE
140 #define CC CONTROL
141 #define CR RETURN
142 #define NA ORDINARY | ALPHA
143 #define NL NEWLINE
144 #define NO ORDINARY
145 #define TB TAB
146 #define VT VTAB
147
148 static u_char const char_type[] = {
149 E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* nul - bel */
150 O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC, /* bs - si */
151 O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC, /* dle - etb */
152 E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* can - us */
153 O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* sp - ' */
154 E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO, /* ( - / */
155 E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* 0 - 7 */
156 O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* 8 - ? */
157 O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* @ - G */
158 E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* H - O */
159 E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* P - W */
160 O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA, /* X - _ */
161 E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* ` - g */
162 O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* h - o */
163 O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* p - w */
164 E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC, /* x - del */
165 /*
166 * Meta chars; should be settable per character set;
167 * for now, treat them all as normal characters.
168 */
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 NA, NA, NA, NA, NA, NA, NA, NA,
185 };
186 #undef BS
187 #undef CC
188 #undef CR
189 #undef NA
190 #undef NL
191 #undef NO
192 #undef TB
193 #undef VT
194
195 /* Macros to clear/set/test flags. */
196 #define SET(t, f) (t) |= (f)
197 #define CLR(t, f) (t) &= ~(f)
198 #define ISSET(t, f) ((t) & (f))
199
200 #undef MAX_INPUT /* XXX wrong in <sys/syslimits.h> */
201 #define MAX_INPUT TTYHOG /* XXX limit is usually larger for !ICANON */
202
203 uint64_t tk_nin;
204 SYSCTL_OPAQUE(_kern, OID_AUTO, tk_nin, CTLFLAG_RD, &tk_nin, sizeof(tk_nin),
205 "LU", "TTY input statistic");
206 uint64_t tk_nout;
207 SYSCTL_OPAQUE(_kern, OID_AUTO, tk_nout, CTLFLAG_RD, &tk_nout, sizeof(tk_nout),
208 "LU", "TTY output statistic");
209 uint64_t tk_rawcc;
210
211 /*
212 * list of struct tty where pstat(8) can pick it up with sysctl
213 */
214 static SLIST_HEAD(, tty) tty_list;
215
216 /*
217 * Initial open of tty, or (re)entry to standard tty line discipline.
218 */
219 int
220 ttyopen(cdev_t device, struct tty *tp)
221 {
222 crit_enter();
223 tp->t_dev = device;
224 if (!ISSET(tp->t_state, TS_ISOPEN)) {
225 SET(tp->t_state, TS_ISOPEN);
226 if (ISSET(tp->t_cflag, CLOCAL)) {
227 SET(tp->t_state, TS_CONNECTED);
228 }
229 bzero(&tp->t_winsize, sizeof(tp->t_winsize));
230 }
231 ttsetwater(tp);
232 crit_exit();
233 return (0);
234 }
235
236 /*
237 * Handle close() on a tty line: flush and set to initial state,
238 * bumping generation number so that pending read/write calls
239 * can detect recycling of the tty.
240 *
241 * XXX our caller should have done `spltty(); l_close(); ttyclose();'
242 * and l_close() should have flushed, but we repeat the spltty() and
243 * the flush in case there are buggy callers.
244 */
245 int
246 ttyclose(struct tty *tp)
247 {
248 funsetown(tp->t_sigio);
249 crit_enter();
250 if (constty == tp)
251 constty = NULL;
252
253 ttyflush(tp, FREAD | FWRITE);
254 clist_free_cblocks(&tp->t_canq);
255 clist_free_cblocks(&tp->t_outq);
256 clist_free_cblocks(&tp->t_rawq);
257
258 tp->t_gen++;
259 tp->t_line = TTYDISC;
260 ttyclearsession(tp);
261 tp->t_state = 0;
262 crit_exit();
263 return (0);
264 }
265
266 /*
267 * Disassociate the tty from its session. Traditionally this has only been
268 * a half-close, meaning that the session was still allowed to point at the
269 * tty (resulting in the tty in the ps command showing something like 'p0-'),
270 * even though the tty is no longer pointing at the session.
271 *
272 * The half close seems to be useful only for 'ps' output but there is as
273 * yet no reason to remove the feature. The full-close code is currently
274 * #if 0'd out. See also sess_rele() in kern/kern_proc.c.
275 */
276 void
277 ttyclearsession(struct tty *tp)
278 {
279 struct session *sp;
280
281 tp->t_pgrp = NULL;
282 if ((sp = tp->t_session) != NULL) {
283 tp->t_session = NULL;
284 #ifdef TTY_DO_FULL_CLOSE
285 /* FULL CLOSE (not yet) */
286 if (sp->s_ttyp == tp) {
287 sp->s_ttyp = NULL;
288 } else {
289 kprintf("ttyclearsession: warning: sp->s_ttyp != tp "
290 "%p/%p\n", sp->s_ttyp, tp);
291 }
292 #endif
293 }
294 }
295
296 /*
297 * Release the tty vnode association for a session. This is the
298 * 'other half' of the close. Because multiple opens of /dev/tty
299 * only generate a single open to the actual tty, the file modes
300 * are locked to FREAD|FWRITE.
301 *
302 * If dorevoke is non-zero, the session is also revoked. We have to
303 * close the vnode if VCTTYISOPEN is set.
304 */
305 void
306 ttyclosesession(struct session *sp, int dorevoke)
307 {
308 struct vnode *vp;
309
310 retry:
311 /*
312 * There may not be a controlling terminal or it may have been closed
313 * out from under us.
314 */
315 if ((vp = sp->s_ttyvp) == NULL)
316 return;
317
318 /*
319 * We need a lock if we have to close or revoke.
320 */
321 if ((vp->v_flag & VCTTYISOPEN) || dorevoke) {
322 vhold(vp);
323 if (vn_lock(vp, LK_EXCLUSIVE|LK_RETRY)) {
324 vdrop(vp);
325 goto retry;
326 }
327
328 /*
329 * Retry if the vnode was ripped out from under us
330 */
331 if (vp != sp->s_ttyvp) {
332 vn_unlock(vp);
333 vdrop(vp);
334 goto retry;
335 }
336
337 /*
338 * Close and revoke as needed
339 */
340 sp->s_ttyvp = NULL;
341 if (vp->v_flag & VCTTYISOPEN) {
342 vclrflags(vp, VCTTYISOPEN);
343 VOP_CLOSE(vp, FREAD|FWRITE);
344 }
345 vn_unlock(vp);
346 if (dorevoke)
347 vrevoke(vp, proc0.p_ucred);
348 vdrop(vp);
349 } else {
350 sp->s_ttyvp = NULL;
351 }
352 vrele(vp);
353 }
354
355 #define FLUSHQ(q) { \
356 if ((q)->c_cc) \
357 ndflush(q, (q)->c_cc); \
358 }
359
360 /* Is 'c' a line delimiter ("break" character)? */
361 #define TTBREAKC(c, lflag) \
362 ((c) == '\n' || (((c) == cc[VEOF] || \
363 (c) == cc[VEOL] || ((c) == cc[VEOL2] && lflag & IEXTEN)) && \
364 (c) != _POSIX_VDISABLE))
365
366 /*
367 * Process input of a single character received on a tty.
368 */
369 int
370 ttyinput(int c, struct tty *tp)
371 {
372 tcflag_t iflag, lflag;
373 cc_t *cc;
374 int i, err;
375
376 /*
377 * If input is pending take it first.
378 */
379 lflag = tp->t_lflag;
380 if (ISSET(lflag, PENDIN))
381 ttypend(tp);
382 /*
383 * Gather stats.
384 */
385 if (ISSET(lflag, ICANON))
386 ++tp->t_cancc;
387 else
388 ++tp->t_rawcc;
389 ++tk_nin;
390
391 /*
392 * Block further input iff:
393 * current input > threshold AND input is available to user program
394 * AND input flow control is enabled and not yet invoked.
395 * The 3 is slop for PARMRK.
396 */
397 iflag = tp->t_iflag;
398 if (tp->t_rawq.c_cc + tp->t_canq.c_cc > tp->t_ihiwat - 3 &&
399 (!ISSET(lflag, ICANON) || tp->t_canq.c_cc != 0) &&
400 (ISSET(tp->t_cflag, CRTS_IFLOW) || ISSET(iflag, IXOFF)) &&
401 !ISSET(tp->t_state, TS_TBLOCK))
402 ttyblock(tp);
403
404 /* Handle exceptional conditions (break, parity, framing). */
405 cc = tp->t_cc;
406 err = (ISSET(c, TTY_ERRORMASK));
407 if (err) {
408 CLR(c, TTY_ERRORMASK);
409 if (ISSET(err, TTY_BI)) {
410 if (ISSET(iflag, IGNBRK))
411 return (0);
412 if (ISSET(iflag, BRKINT)) {
413 ttyflush(tp, FREAD | FWRITE);
414 pgsignal(tp->t_pgrp, SIGINT, 1);
415 goto endcase;
416 }
417 if (ISSET(iflag, PARMRK))
418 goto parmrk;
419 } else if ((ISSET(err, TTY_PE) && ISSET(iflag, INPCK))
420 || ISSET(err, TTY_FE)) {
421 if (ISSET(iflag, IGNPAR))
422 return (0);
423 else if (ISSET(iflag, PARMRK)) {
424 parmrk:
425 if (tp->t_rawq.c_cc + tp->t_canq.c_cc >
426 MAX_INPUT - 3)
427 goto input_overflow;
428 clist_putc(0377 | TTY_QUOTE, &tp->t_rawq);
429 clist_putc(0 | TTY_QUOTE, &tp->t_rawq);
430 clist_putc(c | TTY_QUOTE, &tp->t_rawq);
431 goto endcase;
432 } else
433 c = 0;
434 }
435 }
436
437 if (!ISSET(tp->t_state, TS_TYPEN) && ISSET(iflag, ISTRIP))
438 CLR(c, 0x80);
439 if (!ISSET(lflag, EXTPROC)) {
440 /*
441 * Check for literal nexting very first
442 */
443 if (ISSET(tp->t_state, TS_LNCH)) {
444 SET(c, TTY_QUOTE);
445 CLR(tp->t_state, TS_LNCH);
446 }
447 /*
448 * Scan for special characters. This code
449 * is really just a big case statement with
450 * non-constant cases. The bottom of the
451 * case statement is labeled ``endcase'', so goto
452 * it after a case match, or similar.
453 */
454
455 /*
456 * Control chars which aren't controlled
457 * by ICANON, ISIG, or IXON.
458 */
459 if (ISSET(lflag, IEXTEN)) {
460 if (CCEQ(cc[VLNEXT], c)) {
461 if (ISSET(lflag, ECHO)) {
462 if (ISSET(lflag, ECHOE)) {
463 (void)ttyoutput('^', tp);
464 (void)ttyoutput('\b', tp);
465 } else
466 ttyecho(c, tp);
467 }
468 SET(tp->t_state, TS_LNCH);
469 goto endcase;
470 }
471 if (CCEQ(cc[VDISCARD], c)) {
472 if (ISSET(lflag, FLUSHO))
473 CLR(tp->t_lflag, FLUSHO);
474 else {
475 ttyflush(tp, FWRITE);
476 ttyecho(c, tp);
477 if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
478 ttyretype(tp);
479 SET(tp->t_lflag, FLUSHO);
480 }
481 goto startoutput;
482 }
483 }
484 /*
485 * Signals.
486 */
487 if (ISSET(lflag, ISIG)) {
488 if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
489 if (!ISSET(lflag, NOFLSH))
490 ttyflush(tp, FREAD | FWRITE);
491 ttyecho(c, tp);
492 pgsignal(tp->t_pgrp,
493 CCEQ(cc[VINTR], c) ? SIGINT : SIGQUIT, 1);
494 goto endcase;
495 }
496 if (CCEQ(cc[VSUSP], c)) {
497 if (!ISSET(lflag, NOFLSH))
498 ttyflush(tp, FREAD);
499 ttyecho(c, tp);
500 pgsignal(tp->t_pgrp, SIGTSTP, 1);
501 goto endcase;
502 }
503 }
504 /*
505 * Handle start/stop characters.
506 */
507 if (ISSET(iflag, IXON)) {
508 if (CCEQ(cc[VSTOP], c)) {
509 if (!ISSET(tp->t_state, TS_TTSTOP)) {
510 SET(tp->t_state, TS_TTSTOP);
511 (*tp->t_stop)(tp, 0);
512 return (0);
513 }
514 if (!CCEQ(cc[VSTART], c))
515 return (0);
516 /*
517 * if VSTART == VSTOP then toggle
518 */
519 goto endcase;
520 }
521 if (CCEQ(cc[VSTART], c))
522 goto restartoutput;
523 }
524 /*
525 * IGNCR, ICRNL, & INLCR
526 */
527 if (c == '\r') {
528 if (ISSET(iflag, IGNCR))
529 return (0);
530 else if (ISSET(iflag, ICRNL))
531 c = '\n';
532 } else if (c == '\n' && ISSET(iflag, INLCR))
533 c = '\r';
534 }
535 if (!ISSET(tp->t_lflag, EXTPROC) && ISSET(lflag, ICANON)) {
536 /*
537 * From here on down canonical mode character
538 * processing takes place.
539 */
540 /*
541 * erase or erase2 (^H / ^?)
542 */
543 if (CCEQ(cc[VERASE], c) || CCEQ(cc[VERASE2], c) ) {
544 if (tp->t_rawq.c_cc)
545 ttyrub(clist_unputc(&tp->t_rawq), tp);
546 goto endcase;
547 }
548 /*
549 * kill (^U)
550 */
551 if (CCEQ(cc[VKILL], c)) {
552 if (ISSET(lflag, ECHOKE) &&
553 tp->t_rawq.c_cc == tp->t_rocount &&
554 !ISSET(lflag, ECHOPRT))
555 while (tp->t_rawq.c_cc)
556 ttyrub(clist_unputc(&tp->t_rawq), tp);
557 else {
558 ttyecho(c, tp);
559 if (ISSET(lflag, ECHOK) ||
560 ISSET(lflag, ECHOKE))
561 ttyecho('\n', tp);
562 FLUSHQ(&tp->t_rawq);
563 tp->t_rocount = 0;
564 }
565 CLR(tp->t_state, TS_LOCAL);
566 goto endcase;
567 }
568 /*
569 * word erase (^W)
570 */
571 if (CCEQ(cc[VWERASE], c) && ISSET(lflag, IEXTEN)) {
572 int ctype;
573
574 /*
575 * erase whitespace
576 */
577 while ((c = clist_unputc(&tp->t_rawq)) == ' ' || c == '\t')
578 ttyrub(c, tp);
579 if (c == -1)
580 goto endcase;
581 /*
582 * erase last char of word and remember the
583 * next chars type (for ALTWERASE)
584 */
585 ttyrub(c, tp);
586 c = clist_unputc(&tp->t_rawq);
587 if (c == -1)
588 goto endcase;
589 if (c == ' ' || c == '\t') {
590 clist_putc(c, &tp->t_rawq);
591 goto endcase;
592 }
593 ctype = ISALPHA(c);
594 /*
595 * erase rest of word
596 */
597 do {
598 ttyrub(c, tp);
599 c = clist_unputc(&tp->t_rawq);
600 if (c == -1)
601 goto endcase;
602 } while (c != ' ' && c != '\t' &&
603 (!ISSET(lflag, ALTWERASE) || ISALPHA(c) == ctype));
604 clist_putc(c, &tp->t_rawq);
605 goto endcase;
606 }
607 /*
608 * reprint line (^R)
609 */
610 if (CCEQ(cc[VREPRINT], c) && ISSET(lflag, IEXTEN)) {
611 ttyretype(tp);
612 goto endcase;
613 }
614 /*
615 * ^T - kernel info and generate SIGINFO
616 */
617 if (CCEQ(cc[VSTATUS], c) && ISSET(lflag, IEXTEN)) {
618 if (ISSET(lflag, ISIG))
619 pgsignal(tp->t_pgrp, SIGINFO, 1);
620 if (!ISSET(lflag, NOKERNINFO))
621 ttyinfo(tp);
622 goto endcase;
623 }
624 if (CCEQ(cc[VCHECKPT], c) && ISSET(lflag, IEXTEN)) {
625 if (ISSET(lflag, ISIG))
626 pgsignal(tp->t_pgrp, SIGCKPT, 1);
627 goto endcase;
628 }
629 }
630 /*
631 * Check for input buffer overflow
632 */
633 if (tp->t_rawq.c_cc + tp->t_canq.c_cc >= MAX_INPUT) {
634 input_overflow:
635 if (ISSET(iflag, IMAXBEL)) {
636 if (tp->t_outq.c_cc < tp->t_ohiwat)
637 (void)ttyoutput(CTRL('g'), tp);
638 }
639 goto endcase;
640 }
641
642 if ( c == 0377 && ISSET(iflag, PARMRK) && !ISSET(iflag, ISTRIP)
643 && ISSET(iflag, IGNBRK|IGNPAR) != (IGNBRK|IGNPAR))
644 clist_putc(0377 | TTY_QUOTE, &tp->t_rawq);
645
646 /*
647 * Put data char in q for user and
648 * wakeup on seeing a line delimiter.
649 */
650 if (clist_putc(c, &tp->t_rawq) >= 0) {
651 if (!ISSET(lflag, ICANON)) {
652 ttwakeup(tp);
653 ttyecho(c, tp);
654 goto endcase;
655 }
656 if (TTBREAKC(c, lflag)) {
657 tp->t_rocount = 0;
658 catq(&tp->t_rawq, &tp->t_canq);
659 ttwakeup(tp);
660 } else if (tp->t_rocount++ == 0)
661 tp->t_rocol = tp->t_column;
662 if (ISSET(tp->t_state, TS_ERASE)) {
663 /*
664 * end of prterase \.../
665 */
666 CLR(tp->t_state, TS_ERASE);
667 (void)ttyoutput('/', tp);
668 }
669 i = tp->t_column;
670 ttyecho(c, tp);
671 if (CCEQ(cc[VEOF], c) && ISSET(lflag, ECHO)) {
672 /*
673 * Place the cursor over the '^' of the ^D.
674 */
675 i = imin(2, tp->t_column - i);
676 while (i > 0) {
677 (void)ttyoutput('\b', tp);
678 i--;
679 }
680 }
681 }
682 endcase:
683 /*
684 * IXANY means allow any character to restart output.
685 */
686 if (ISSET(tp->t_state, TS_TTSTOP) &&
687 !ISSET(iflag, IXANY) && cc[VSTART] != cc[VSTOP])
688 return (0);
689 restartoutput:
690 CLR(tp->t_lflag, FLUSHO);
691 CLR(tp->t_state, TS_TTSTOP);
692 startoutput:
693 return (ttstart(tp));
694 }
695
696 /*
697 * Output a single character on a tty, doing output processing
698 * as needed (expanding tabs, newline processing, etc.).
699 * Returns < 0 if succeeds, otherwise returns char to resend.
700 * Must be recursive.
701 */
702 static int
703 ttyoutput(int c, struct tty *tp)
704 {
705 tcflag_t oflag;
706 int col;
707
708 oflag = tp->t_oflag;
709 if (!ISSET(oflag, OPOST)) {
710 if (ISSET(tp->t_lflag, FLUSHO))
711 return (-1);
712 if (clist_putc(c, &tp->t_outq))
713 return (c);
714 tk_nout++;
715 tp->t_outcc++;
716 return (-1);
717 }
718 /*
719 * Do tab expansion if OXTABS is set. Special case if we external
720 * processing, we don't do the tab expansion because we'll probably
721 * get it wrong. If tab expansion needs to be done, let it happen
722 * externally.
723 */
724 CLR(c, ~TTY_CHARMASK);
725 if (c == '\t' &&
726 ISSET(oflag, OXTABS) && !ISSET(tp->t_lflag, EXTPROC)) {
727 c = 8 - (tp->t_column & 7);
728 if (!ISSET(tp->t_lflag, FLUSHO)) {
729 crit_enter(); /* Don't interrupt tabs. */
730 c -= b_to_q(" ", c, &tp->t_outq);
731 tk_nout += c;
732 tp->t_outcc += c;
733 crit_exit();
734 }
735 tp->t_column += c;
736 return (c ? -1 : '\t');
737 }
738 if (c == CEOT && ISSET(oflag, ONOEOT))
739 return (-1);
740
741 /*
742 * Newline translation: if ONLCR is set,
743 * translate newline into "\r\n".
744 */
745 if (c == '\n' && ISSET(tp->t_oflag, ONLCR)) {
746 tk_nout++;
747 tp->t_outcc++;
748 if (!ISSET(tp->t_lflag, FLUSHO) && clist_putc('\r', &tp->t_outq))
749 return (c);
750 }
751 /* If OCRNL is set, translate "\r" into "\n". */
752 else if (c == '\r' && ISSET(tp->t_oflag, OCRNL))
753 c = '\n';
754 /* If ONOCR is set, don't transmit CRs when on column 0. */
755 else if (c == '\r' && ISSET(tp->t_oflag, ONOCR) && tp->t_column == 0)
756 return (-1);
757
758 tk_nout++;
759 tp->t_outcc++;
760 if (!ISSET(tp->t_lflag, FLUSHO) && clist_putc(c, &tp->t_outq))
761 return (c);
762
763 col = tp->t_column;
764 switch (CCLASS(c)) {
765 case BACKSPACE:
766 if (col > 0)
767 --col;
768 break;
769 case CONTROL:
770 break;
771 case NEWLINE:
772 if (ISSET(tp->t_oflag, ONLCR | ONLRET))
773 col = 0;
774 break;
775 case RETURN:
776 col = 0;
777 break;
778 case ORDINARY:
779 ++col;
780 break;
781 case TAB:
782 col = (col + 8) & ~7;
783 break;
784 }
785 tp->t_column = col;
786 return (-1);
787 }
788
789 /*
790 * Ioctls for all tty devices. Called after line-discipline specific ioctl
791 * has been called to do discipline-specific functions and/or reject any
792 * of these ioctl commands.
793 */
794 /* ARGSUSED */
795 int
796 ttioctl(struct tty *tp, u_long cmd, void *data, int flag)
797 {
798 struct thread *td = curthread;
799 struct lwp *lp = td->td_lwp;
800 struct proc *p = td->td_proc;
801 int error;
802
803 KKASSERT(p);
804
805 /* If the ioctl involves modification, hang if in the background. */
806 switch (cmd) {
807 case TIOCCBRK:
808 case TIOCCONS:
809 case TIOCDRAIN:
810 case TIOCEXCL:
811 case TIOCFLUSH:
812 #ifdef TIOCHPCL
813 case TIOCHPCL:
814 #endif
815 case TIOCNXCL:
816 case TIOCSBRK:
817 case TIOCSCTTY:
818 case TIOCSDRAINWAIT:
819 case TIOCSETA:
820 case TIOCSETAF:
821 case TIOCSETAW:
822 case TIOCSETD:
823 case TIOCSPGRP:
824 case TIOCSTART:
825 case TIOCSTAT:
826 case TIOCSTI:
827 case TIOCSTOP:
828 case TIOCSWINSZ:
829 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
830 case TIOCLBIC:
831 case TIOCLBIS:
832 case TIOCLSET:
833 case TIOCSETC:
834 case OTIOCSETD:
835 case TIOCSETN:
836 case TIOCSETP:
837 case TIOCSLTC:
838 #endif
839 while (isbackground(p, tp) && !(p->p_flag & P_PPWAIT) &&
840 !SIGISMEMBER(p->p_sigignore, SIGTTOU) &&
841 !SIGISMEMBER(lp->lwp_sigmask, SIGTTOU)) {
842 if (p->p_pgrp->pg_jobc == 0)
843 return (EIO);
844 pgsignal(p->p_pgrp, SIGTTOU, 1);
845 error = ttysleep(tp, &lbolt, PCATCH, "ttybg1",
846 0);
847 if (error)
848 return (error);
849 }
850 break;
851 }
852
853 switch (cmd) { /* Process the ioctl. */
854 case FIOASYNC: /* set/clear async i/o */
855 crit_enter();
856 if (*(int *)data)
857 SET(tp->t_state, TS_ASYNC);
858 else
859 CLR(tp->t_state, TS_ASYNC);
860 crit_exit();
861 break;
862 case FIONREAD: /* get # bytes to read */
863 crit_enter();
864 *(int *)data = ttnread(tp);
865 crit_exit();
866 break;
867
868 case FIOSETOWN:
869 /*
870 * Policy -- Don't allow FIOSETOWN on someone else's
871 * controlling tty
872 */
873 if (tp->t_session != NULL && !isctty(p, tp))
874 return (ENOTTY);
875
876 error = fsetown(*(int *)data, &tp->t_sigio);
877 if (error)
878 return (error);
879 break;
880 case FIOGETOWN:
881 if (tp->t_session != NULL && !isctty(p, tp))
882 return (ENOTTY);
883 *(int *)data = fgetown(tp->t_sigio);
884 break;
885
886 case TIOCEXCL: /* set exclusive use of tty */
887 crit_enter();
888 SET(tp->t_state, TS_XCLUDE);
889 crit_exit();
890 break;
891 case TIOCFLUSH: { /* flush buffers */
892 int flags = *(int *)data;
893
894 if (flags == 0)
895 flags = FREAD | FWRITE;
896 else
897 flags &= FREAD | FWRITE;
898 ttyflush(tp, flags);
899 break;
900 }
901 case TIOCCONS: /* become virtual console */
902 if (*(int *)data) {
903 if (constty && constty != tp &&
904 ISSET(constty->t_state, TS_CONNECTED))
905 return (EBUSY);
906 #ifndef UCONSOLE
907 if ((error = priv_check(td, PRIV_ROOT)) != 0)
908 return (error);
909 #endif
910 constty = tp;
911 } else if (tp == constty)
912 constty = NULL;
913 break;
914 case TIOCDRAIN: /* wait till output drained */
915 error = ttywait(tp);
916 if (error)
917 return (error);
918 break;
919 case TIOCGETA: { /* get termios struct */
920 struct termios *t = (struct termios *)data;
921
922 bcopy(&tp->t_termios, t, sizeof(struct termios));
923 break;
924 }
925 case TIOCGETD: /* get line discipline */
926 *(int *)data = tp->t_line;
927 break;
928 case TIOCGWINSZ: /* get window size */
929 *(struct winsize *)data = tp->t_winsize;
930 break;
931 case TIOCGPGRP: /* get pgrp of tty */
932 if (!isctty(p, tp))
933 return (ENOTTY);
934 *(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PID;
935 break;
936 case TIOCGSID: /* get sid of tty */
937 if (!isctty(p, tp))
938 return (ENOTTY);
939 *(int *)data = tp->t_session->s_sid;
940 break;
941 #ifdef TIOCHPCL
942 case TIOCHPCL: /* hang up on last close */
943 crit_enter();
944 SET(tp->t_cflag, HUPCL);
945 crit_exit();
946 break;
947 #endif
948 case TIOCNXCL: /* reset exclusive use of tty */
949 crit_enter();
950 CLR(tp->t_state, TS_XCLUDE);
951 crit_exit();
952 break;
953 case TIOCOUTQ: /* output queue size */
954 *(int *)data = tp->t_outq.c_cc;
955 break;
956 case TIOCSETA: /* set termios struct */
957 case TIOCSETAW: /* drain output, set */
958 case TIOCSETAF: { /* drn out, fls in, set */
959 struct termios *t = (struct termios *)data;
960
961 if (t->c_ispeed == 0)
962 t->c_ispeed = t->c_ospeed;
963 if (t->c_ispeed == 0)
964 t->c_ispeed = tp->t_ospeed;
965 if (t->c_ispeed == 0)
966 return (EINVAL);
967 crit_enter();
968 if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
969 error = ttywait(tp);
970 if (error) {
971 crit_exit();
972 return (error);
973 }
974 if (cmd == TIOCSETAF)
975 ttyflush(tp, FREAD);
976 }
977 if (!ISSET(t->c_cflag, CIGNORE)) {
978 /*
979 * Set device hardware.
980 */
981 if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
982 crit_exit();
983 return (error);
984 }
985 if (ISSET(t->c_cflag, CLOCAL) &&
986 !ISSET(tp->t_cflag, CLOCAL)) {
987 /*
988 * XXX disconnections would be too hard to
989 * get rid of without this kludge. The only
990 * way to get rid of controlling terminals
991 * is to exit from the session leader.
992 */
993 CLR(tp->t_state, TS_ZOMBIE);
994
995 wakeup(TSA_CARR_ON(tp));
996 ttwakeup(tp);
997 ttwwakeup(tp);
998 }
999 if ((ISSET(tp->t_state, TS_CARR_ON) ||
1000 ISSET(t->c_cflag, CLOCAL)) &&
1001 !ISSET(tp->t_state, TS_ZOMBIE))
1002 SET(tp->t_state, TS_CONNECTED);
1003 else
1004 CLR(tp->t_state, TS_CONNECTED);
1005 tp->t_cflag = t->c_cflag;
1006 tp->t_ispeed = t->c_ispeed;
1007 if (t->c_ospeed != 0)
1008 tp->t_ospeed = t->c_ospeed;
1009 ttsetwater(tp);
1010 }
1011 if (ISSET(t->c_lflag, ICANON) != ISSET(tp->t_lflag, ICANON) &&
1012 cmd != TIOCSETAF) {
1013 if (ISSET(t->c_lflag, ICANON))
1014 SET(tp->t_lflag, PENDIN);
1015 else {
1016 /*
1017 * XXX we really shouldn't allow toggling
1018 * ICANON while we're in a non-termios line
1019 * discipline. Now we have to worry about
1020 * panicing for a null queue.
1021 */
1022 if (tp->t_canq.c_cbreserved > 0 &&
1023 tp->t_rawq.c_cbreserved > 0) {
1024 catq(&tp->t_rawq, &tp->t_canq);
1025 /*
1026 * XXX the queue limits may be
1027 * different, so the old queue
1028 * swapping method no longer works.
1029 */
1030 catq(&tp->t_canq, &tp->t_rawq);
1031 }
1032 CLR(tp->t_lflag, PENDIN);
1033 }
1034 ttwakeup(tp);
1035 }
1036 tp->t_iflag = t->c_iflag;
1037 tp->t_oflag = t->c_oflag;
1038 /*
1039 * Make the EXTPROC bit read only.
1040 */
1041 if (ISSET(tp->t_lflag, EXTPROC))
1042 SET(t->c_lflag, EXTPROC);
1043 else
1044 CLR(t->c_lflag, EXTPROC);
1045 tp->t_lflag = t->c_lflag | ISSET(tp->t_lflag, PENDIN);
1046 if (t->c_cc[VMIN] != tp->t_cc[VMIN] ||
1047 t->c_cc[VTIME] != tp->t_cc[VTIME])
1048 ttwakeup(tp);
1049 bcopy(t->c_cc, tp->t_cc, sizeof(t->c_cc));
1050 crit_exit();
1051 break;
1052 }
1053 case TIOCSETD: { /* set line discipline */
1054 int t = *(int *)data;
1055 cdev_t device = tp->t_dev;
1056
1057 if ((u_int)t >= nlinesw)
1058 return (ENXIO);
1059 if (t != tp->t_line) {
1060 crit_enter();
1061 (*linesw[tp->t_line].l_close)(tp, flag);
1062 error = (*linesw[t].l_open)(device, tp);
1063 if (error) {
1064 (void)(*linesw[tp->t_line].l_open)(device, tp);
1065 crit_exit();
1066 return (error);
1067 }
1068 tp->t_line = t;
1069 crit_exit();
1070 }
1071 break;
1072 }
1073 case TIOCSTART: /* start output, like ^Q */
1074 crit_enter();
1075 if (ISSET(tp->t_state, TS_TTSTOP) ||
1076 ISSET(tp->t_lflag, FLUSHO)) {
1077 CLR(tp->t_lflag, FLUSHO);
1078 CLR(tp->t_state, TS_TTSTOP);
1079 ttstart(tp);
1080 }
1081 crit_exit();
1082 break;
1083 case TIOCSTI: /* simulate terminal input */
1084 if ((flag & FREAD) == 0 && priv_check(td, PRIV_ROOT))
1085 return (EPERM);
1086 if (!isctty(p, tp) && priv_check(td, PRIV_ROOT))
1087 return (EACCES);
1088 crit_enter();
1089 (*linesw[tp->t_line].l_rint)(*(u_char *)data, tp);
1090 crit_exit();
1091 break;
1092 case TIOCSTOP: /* stop output, like ^S */
1093 crit_enter();
1094 if (!ISSET(tp->t_state, TS_TTSTOP)) {
1095 SET(tp->t_state, TS_TTSTOP);
1096 (*tp->t_stop)(tp, 0);
1097 }
1098 crit_exit();
1099 break;
1100 case TIOCSCTTY: /* become controlling tty */
1101 /* Session ctty vnode pointer set in vnode layer. */
1102 if (!SESS_LEADER(p) ||
1103 ((p->p_session->s_ttyvp || tp->t_session) &&
1104 (tp->t_session != p->p_session)))
1105 return (EPERM);
1106 tp->t_session = p->p_session;
1107 tp->t_pgrp = p->p_pgrp;
1108 p->p_session->s_ttyp = tp;
1109 p->p_flag |= P_CONTROLT;
1110 break;
1111 case TIOCSPGRP: { /* set pgrp of tty */
1112 pid_t pgid = *(int *)data;
1113
1114 if (!isctty(p, tp))
1115 return (ENOTTY);
1116 else if (pgid < 1 || pgid > PID_MAX)
1117 return (EINVAL);
1118 else {
1119 struct pgrp *pgrp = pgfind(pgid);
1120 if (pgrp == NULL || pgrp->pg_session != p->p_session)
1121 return (EPERM);
1122
1123 tp->t_pgrp = pgrp;
1124 }
1125 break;
1126 }
1127 case TIOCSTAT: /* simulate control-T */
1128 crit_enter();
1129 ttyinfo(tp);
1130 crit_exit();
1131 break;
1132 case TIOCSWINSZ: /* set window size */
1133 if (bcmp((caddr_t)&tp->t_winsize, data,
1134 sizeof (struct winsize))) {
1135 tp->t_winsize = *(struct winsize *)data;
1136 pgsignal(tp->t_pgrp, SIGWINCH, 1);
1137 }
1138 break;
1139 case TIOCSDRAINWAIT:
1140 error = priv_check(td, PRIV_ROOT);
1141 if (error)
1142 return (error);
1143 tp->t_timeout = *(int *)data * hz;
1144 wakeup(TSA_OCOMPLETE(tp));
1145 wakeup(TSA_OLOWAT(tp));
1146 break;
1147 case TIOCGDRAINWAIT:
1148 *(int *)data = tp->t_timeout / hz;
1149 break;
1150 default:
1151 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
1152 return (ttcompat(tp, cmd, data, flag));
1153 #else
1154 return (ENOIOCTL);
1155 #endif
1156 }
1157 return (0);
1158 }
1159
1160 int
1161 ttypoll(struct dev_poll_args *ap)
1162 {
1163 cdev_t dev = ap->a_head.a_dev;
1164 int events = ap->a_events;
1165 int revents = 0;
1166 struct tty *tp;
1167
1168 tp = dev->si_tty;
1169 /* XXX used to return ENXIO, but that means true! */
1170 if (tp == NULL) {
1171 ap->a_events = (events & (POLLIN | POLLOUT | POLLRDNORM |
1172 POLLWRNORM)) | POLLHUP;
1173 return(0);
1174 }
1175
1176 crit_enter();
1177 if (events & (POLLIN | POLLRDNORM)) {
1178 if (ttnread(tp) > 0 || ISSET(tp->t_state, TS_ZOMBIE))
1179 revents |= events & (POLLIN | POLLRDNORM);
1180 else
1181 selrecord(curthread, &tp->t_rsel);
1182 }
1183 if (events & (POLLOUT | POLLWRNORM)) {
1184 if ((tp->t_outq.c_cc <= tp->t_olowat &&
1185 ISSET(tp->t_state, TS_CONNECTED))
1186 || ISSET(tp->t_state, TS_ZOMBIE))
1187 revents |= events & (POLLOUT | POLLWRNORM);
1188 else
1189 selrecord(curthread, &tp->t_wsel);
1190 }
1191 crit_exit();
1192 ap->a_events = revents;
1193 return (0);
1194 }
1195
1196 static struct filterops ttyread_filtops =
1197 { 1, NULL, filt_ttyrdetach, filt_ttyread };
1198 static struct filterops ttywrite_filtops =
1199 { 1, NULL, filt_ttywdetach, filt_ttywrite };
1200
1201 int
1202 ttykqfilter(struct dev_kqfilter_args *ap)
1203 {
1204 cdev_t dev = ap->a_head.a_dev;
1205 struct knote *kn = ap->a_kn;
1206 struct tty *tp = dev->si_tty;
1207 struct klist *klist;
1208
1209 ap->a_result = 0;
1210 switch (kn->kn_filter) {
1211 case EVFILT_READ:
1212 klist = &tp->t_rsel.si_note;
1213 kn->kn_fop = &ttyread_filtops;
1214 break;
1215 case EVFILT_WRITE:
1216 klist = &tp->t_wsel.si_note;
1217 kn->kn_fop = &ttywrite_filtops;
1218 break;
1219 default:
1220 ap->a_result = 1;
1221 return (0);
1222 }
1223
1224 kn->kn_hook = (caddr_t)dev;
1225
1226 crit_enter();
1227 SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1228 crit_exit();
1229
1230 return (0);
1231 }
1232
1233 static void
1234 filt_ttyrdetach(struct knote *kn)
1235 {
1236 struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1237
1238 crit_enter();
1239 SLIST_REMOVE(&tp->t_rsel.si_note, kn, knote, kn_selnext);
1240 crit_exit();
1241 }
1242
1243 static int
1244 filt_ttyread(struct knote *kn, long hint)
1245 {
1246 struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1247
1248 kn->kn_data = ttnread(tp);
1249 if (ISSET(tp->t_state, TS_ZOMBIE)) {
1250 kn->kn_flags |= EV_EOF;
1251 return (1);
1252 }
1253 return (kn->kn_data > 0);
1254 }
1255
1256 static void
1257 filt_ttywdetach(struct knote *kn)
1258 {
1259 struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1260
1261 crit_enter();
1262 SLIST_REMOVE(&tp->t_wsel.si_note, kn, knote, kn_selnext);
1263 crit_exit();
1264 }
1265
1266 static int
1267 filt_ttywrite(struct knote *kn, long hint)
1268 {
1269 struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1270
1271 kn->kn_data = tp->t_outq.c_cc;
1272 if (ISSET(tp->t_state, TS_ZOMBIE))
1273 return (1);
1274 return (kn->kn_data <= tp->t_olowat &&
1275 ISSET(tp->t_state, TS_CONNECTED));
1276 }
1277
1278 /*
1279 * Must be called while in a critical section.
1280 */
1281 static int
1282 ttnread(struct tty *tp)
1283 {
1284 int nread;
1285
1286 if (ISSET(tp->t_lflag, PENDIN))
1287 ttypend(tp);
1288 nread = tp->t_canq.c_cc;
1289 if (!ISSET(tp->t_lflag, ICANON)) {
1290 nread += tp->t_rawq.c_cc;
1291 if (nread < tp->t_cc[VMIN] && tp->t_cc[VTIME] == 0)
1292 nread = 0;
1293 }
1294 return (nread);
1295 }
1296
1297 /*
1298 * Wait for output to drain.
1299 */
1300 int
1301 ttywait(struct tty *tp)
1302 {
1303 int error;
1304
1305 error = 0;
1306 crit_enter();
1307 while ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1308 ISSET(tp->t_state, TS_CONNECTED) && tp->t_oproc) {
1309 (*tp->t_oproc)(tp);
1310 if ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1311 ISSET(tp->t_state, TS_CONNECTED)) {
1312 SET(tp->t_state, TS_SO_OCOMPLETE);
1313 error = ttysleep(tp, TSA_OCOMPLETE(tp),
1314 PCATCH, "ttywai",
1315 tp->t_timeout);
1316 if (error) {
1317 if (error == EWOULDBLOCK)
1318 error = EIO;
1319 break;
1320 }
1321 } else
1322 break;
1323 }
1324 if (!error && (tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)))
1325 error = EIO;
1326 crit_exit();
1327 return (error);
1328 }
1329
1330 /*
1331 * Flush if successfully wait.
1332 */
1333 static int
1334 ttywflush(struct tty *tp)
1335 {
1336 int error;
1337
1338 if ((error = ttywait(tp)) == 0)
1339 ttyflush(tp, FREAD);
1340 return (error);
1341 }
1342
1343 /*
1344 * Flush tty read and/or write queues, notifying anyone waiting.
1345 */
1346 void
1347 ttyflush(struct tty *tp, int rw)
1348 {
1349 crit_enter();
1350 #if 0
1351 again:
1352 #endif
1353 if (rw & FWRITE) {
1354 FLUSHQ(&tp->t_outq);
1355 CLR(tp->t_state, TS_TTSTOP);
1356 }
1357 (*tp->t_stop)(tp, rw);
1358 if (rw & FREAD) {
1359 FLUSHQ(&tp->t_canq);
1360 FLUSHQ(&tp->t_rawq);
1361 CLR(tp->t_lflag, PENDIN);
1362 tp->t_rocount = 0;
1363 tp->t_rocol = 0;
1364 CLR(tp->t_state, TS_LOCAL);
1365 ttwakeup(tp);
1366 if (ISSET(tp->t_state, TS_TBLOCK)) {
1367 if (rw & FWRITE)
1368 FLUSHQ(&tp->t_outq);
1369 ttyunblock(tp);
1370
1371 /*
1372 * Don't let leave any state that might clobber the
1373 * next line discipline (although we should do more
1374 * to send the START char). Not clearing the state
1375 * may have caused the "putc to a clist with no
1376 * reserved cblocks" panic/kprintf.
1377 */
1378 CLR(tp->t_state, TS_TBLOCK);
1379
1380 #if 0 /* forget it, sleeping isn't always safe and we don't know when it is */
1381 if (ISSET(tp->t_iflag, IXOFF)) {
1382 /*
1383 * XXX wait a bit in the hope that the stop
1384 * character (if any) will go out. Waiting
1385 * isn't good since it allows races. This
1386 * will be fixed when the stop character is
1387 * put in a special queue. Don't bother with
1388 * the checks in ttywait() since the timeout
1389 * will save us.
1390 */
1391 SET(tp->t_state, TS_SO_OCOMPLETE);
1392 ttysleep(tp, TSA_OCOMPLETE(tp), 0,
1393 "ttyfls", hz / 10);
1394 /*
1395 * Don't try sending the stop character again.
1396 */
1397 CLR(tp->t_state, TS_TBLOCK);
1398 goto again;
1399 }
1400 #endif
1401 }
1402 }
1403 if (rw & FWRITE) {
1404 FLUSHQ(&tp->t_outq);
1405 ttwwakeup(tp);
1406 }
1407 crit_exit();
1408 }
1409
1410 /*
1411 * Copy in the default termios characters.
1412 */
1413 void
1414 termioschars(struct termios *t)
1415 {
1416
1417 bcopy(ttydefchars, t->c_cc, sizeof t->c_cc);
1418 }
1419
1420 /*
1421 * Old interface.
1422 */
1423 void
1424 ttychars(struct tty *tp)
1425 {
1426
1427 termioschars(&tp->t_termios);
1428 }
1429
1430 /*
1431 * Handle input high water. Send stop character for the IXOFF case. Turn
1432 * on our input flow control bit and propagate the changes to the driver.
1433 * XXX the stop character should be put in a special high priority queue.
1434 */
1435 void
1436 ttyblock(struct tty *tp)
1437 {
1438
1439 SET(tp->t_state, TS_TBLOCK);
1440 if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTOP] != _POSIX_VDISABLE &&
1441 clist_putc(tp->t_cc[VSTOP], &tp->t_outq) != 0)
1442 CLR(tp->t_state, TS_TBLOCK); /* try again later */
1443 ttstart(tp);
1444 }
1445
1446 /*
1447 * Handle input low water. Send start character for the IXOFF case. Turn
1448 * off our input flow control bit and propagate the changes to the driver.
1449 * XXX the start character should be put in a special high priority queue.
1450 */
1451 static void
1452 ttyunblock(struct tty *tp)
1453 {
1454
1455 CLR(tp->t_state, TS_TBLOCK);
1456 if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTART] != _POSIX_VDISABLE &&
1457 clist_putc(tp->t_cc[VSTART], &tp->t_outq) != 0)
1458 SET(tp->t_state, TS_TBLOCK); /* try again later */
1459 ttstart(tp);
1460 }
1461
1462 #ifdef notyet
1463 /* Not used by any current (i386) drivers. */
1464 /*
1465 * Restart after an inter-char delay.
1466 */
1467 void
1468 ttrstrt(void *tp_arg)
1469 {
1470 struct tty *tp;
1471
1472 KASSERT(tp_arg != NULL, ("ttrstrt"));
1473
1474 tp = tp_arg;
1475 crit_enter();
1476 CLR(tp->t_state, TS_TIMEOUT);
1477 ttstart(tp);
1478 crit_exit();
1479 }
1480 #endif
1481
1482 int
1483 ttstart(struct tty *tp)
1484 {
1485
1486 if (tp->t_oproc != NULL) /* XXX: Kludge for pty. */
1487 (*tp->t_oproc)(tp);
1488 return (0);
1489 }
1490
1491 /*
1492 * "close" a line discipline
1493 */
1494 int
1495 ttylclose(struct tty *tp, int flag)
1496 {
1497
1498 if (flag & FNONBLOCK || ttywflush(tp))
1499 ttyflush(tp, FREAD | FWRITE);
1500 return (0);
1501 }
1502
1503 /*
1504 * Handle modem control transition on a tty.
1505 * Flag indicates new state of carrier.
1506 * Returns 0 if the line should be turned off, otherwise 1.
1507 */
1508 int
1509 ttymodem(struct tty *tp, int flag)
1510 {
1511
1512 if (ISSET(tp->t_state, TS_CARR_ON) && ISSET(tp->t_cflag, MDMBUF)) {
1513 /*
1514 * MDMBUF: do flow control according to carrier flag
1515 * XXX TS_CAR_OFLOW doesn't do anything yet. TS_TTSTOP
1516 * works if IXON and IXANY are clear.
1517 */
1518 if (flag) {
1519 CLR(tp->t_state, TS_CAR_OFLOW);
1520 CLR(tp->t_state, TS_TTSTOP);
1521 ttstart(tp);
1522 } else if (!ISSET(tp->t_state, TS_CAR_OFLOW)) {
1523 SET(tp->t_state, TS_CAR_OFLOW);
1524 SET(tp->t_state, TS_TTSTOP);
1525 (*tp->t_stop)(tp, 0);
1526 }
1527 } else if (flag == 0) {
1528 /*
1529 * Lost carrier.
1530 */
1531 CLR(tp->t_state, TS_CARR_ON);
1532 if (ISSET(tp->t_state, TS_ISOPEN) &&
1533 !ISSET(tp->t_cflag, CLOCAL)) {
1534 SET(tp->t_state, TS_ZOMBIE);
1535 CLR(tp->t_state, TS_CONNECTED);
1536 if (tp->t_session && tp->t_session->s_leader)
1537 ksignal(tp->t_session->s_leader, SIGHUP);
1538 ttyflush(tp, FREAD | FWRITE);
1539 return (0);
1540 }
1541 } else {
1542 /*
1543 * Carrier now on.
1544 */
1545 SET(tp->t_state, TS_CARR_ON);
1546 if (!ISSET(tp->t_state, TS_ZOMBIE))
1547 SET(tp->t_state, TS_CONNECTED);
1548 wakeup(TSA_CARR_ON(tp));
1549 ttwakeup(tp);
1550 ttwwakeup(tp);
1551 }
1552 return (1);
1553 }
1554
1555 /*
1556 * Reinput pending characters after state switch
1557 * call from a critical section.
1558 */
1559 static void
1560 ttypend(struct tty *tp)
1561 {
1562 struct clist tq;
1563 int c;
1564
1565 CLR(tp->t_lflag, PENDIN);
1566 SET(tp->t_state, TS_TYPEN);
1567 /*
1568 * XXX this assumes too much about clist internals. It may even
1569 * fail if the cblock slush pool is empty. We can't allocate more
1570 * cblocks here because we are called from an interrupt handler
1571 * and clist_alloc_cblocks() can wait.
1572 */
1573 tq = tp->t_rawq;
1574 bzero(&tp->t_rawq, sizeof tp->t_rawq);
1575 tp->t_rawq.c_cbmax = tq.c_cbmax;
1576 tp->t_rawq.c_cbreserved = tq.c_cbreserved;
1577 while ((c = clist_getc(&tq)) >= 0)
1578 ttyinput(c, tp);
1579 CLR(tp->t_state, TS_TYPEN);
1580 }
1581
1582 /*
1583 * Process a read call on a tty device.
1584 */
1585 int
1586 ttread(struct tty *tp, struct uio *uio, int flag)
1587 {
1588 struct clist *qp;
1589 int c;
1590 tcflag_t lflag;
1591 cc_t *cc = tp->t_cc;
1592 struct proc *pp;
1593 struct lwp *lp;
1594 int first, error = 0;
1595 int has_stime = 0, last_cc = 0;
1596 long slp = 0; /* XXX this should be renamed `timo'. */
1597 struct timeval stime;
1598
1599 lp = curthread->td_lwp;
1600 stime.tv_sec = 0; /* fix compiler warnings */
1601 stime.tv_usec = 0;
1602
1603 loop:
1604 crit_enter();
1605 lflag = tp->t_lflag;
1606 /*
1607 * take pending input first
1608 */
1609 if (ISSET(lflag, PENDIN)) {
1610 ttypend(tp);
1611 splz(); /* reduce latency */
1612 lflag = tp->t_lflag; /* XXX ttypend() clobbers it */
1613 }
1614
1615 /*
1616 * Hang process if it's in the background.
1617 */
1618 if ((pp = curproc) && isbackground(pp, tp)) {
1619 crit_exit();
1620 if (SIGISMEMBER(pp->p_sigignore, SIGTTIN) ||
1621 SIGISMEMBER(lp->lwp_sigmask, SIGTTIN) ||
1622 (pp->p_flag & P_PPWAIT) || pp->p_pgrp->pg_jobc == 0)
1623 return (EIO);
1624 pgsignal(pp->p_pgrp, SIGTTIN, 1);
1625 error = ttysleep(tp, &lbolt, PCATCH, "ttybg2", 0);
1626 if (error)
1627 return (error);
1628 goto loop;
1629 }
1630
1631 if (ISSET(tp->t_state, TS_ZOMBIE)) {
1632 crit_exit();
1633 return (0); /* EOF */
1634 }
1635
1636 /*
1637 * If canonical, use the canonical queue,
1638 * else use the raw queue.
1639 *
1640 * (should get rid of clists...)
1641 */
1642 qp = ISSET(lflag, ICANON) ? &tp->t_canq : &tp->t_rawq;
1643
1644 if (flag & IO_NDELAY) {
1645 if (qp->c_cc > 0)
1646 goto read;
1647 if (!ISSET(lflag, ICANON) && cc[VMIN] == 0) {
1648 crit_exit();
1649 return (0);
1650 }
1651 crit_exit();
1652 return (EWOULDBLOCK);
1653 }
1654 if (!ISSET(lflag, ICANON)) {
1655 int m = cc[VMIN];
1656 long t = cc[VTIME];
1657 struct timeval timecopy;
1658
1659 /*
1660 * Check each of the four combinations.
1661 * (m > 0 && t == 0) is the normal read case.
1662 * It should be fairly efficient, so we check that and its
1663 * companion case (m == 0 && t == 0) first.
1664 * For the other two cases, we compute the target sleep time
1665 * into slp.
1666 */
1667 if (t == 0) {
1668 if (qp->c_cc < m)
1669 goto sleep;
1670 if (qp->c_cc > 0)
1671 goto read;
1672
1673 /* m, t and qp->c_cc are all 0. 0 is enough input. */
1674 crit_exit();
1675 return (0);
1676 }
1677 t *= 100000; /* time in us */
1678 #define diff(t1, t2) (((t1).tv_sec - (t2).tv_sec) * 1000000 + \
1679 ((t1).tv_usec - (t2).tv_usec))
1680 if (m > 0) {
1681 if (qp->c_cc <= 0)
1682 goto sleep;
1683 if (qp->c_cc >= m)
1684 goto read;
1685 getmicrotime(&timecopy);
1686 if (has_stime == 0) {
1687 /* first character, start timer */
1688 has_stime = 1;
1689 stime = timecopy;
1690 slp = t;
1691 } else if (qp->c_cc > last_cc) {
1692 /* got a character, restart timer */
1693 stime = timecopy;
1694 slp = t;
1695 } else {
1696 /* nothing, check expiration */
1697 slp = t - diff(timecopy, stime);
1698 if (slp <= 0)
1699 goto read;
1700 }
1701 last_cc = qp->c_cc;
1702 } else { /* m == 0 */
1703 if (qp->c_cc > 0)
1704 goto read;
1705 getmicrotime(&timecopy);
1706 if (has_stime == 0) {
1707 has_stime = 1;
1708 stime = timecopy;
1709 slp = t;
1710 } else {
1711 slp = t - diff(timecopy, stime);
1712 if (slp <= 0) {
1713 /* Timed out, but 0 is enough input. */
1714 crit_exit();
1715 return (0);
1716 }
1717 }
1718 }
1719 #undef diff
1720 /*
1721 * Rounding down may make us wake up just short
1722 * of the target, so we round up.
1723 * The formula is ceiling(slp * hz/1000000).
1724 * 32-bit arithmetic is enough for hz < 169.
1725 * XXX see tvtohz() for how to avoid overflow if hz
1726 * is large (divide by `tick' and/or arrange to
1727 * use tvtohz() if hz is large).
1728 */
1729 slp = (long) (((u_long)slp * hz) + 999999) / 1000000;
1730 goto sleep;
1731 }
1732 if (qp->c_cc <= 0) {
1733 sleep:
1734 /*
1735 * There is no input, or not enough input and we can block.
1736 */
1737 error = ttysleep(tp, TSA_HUP_OR_INPUT(tp), PCATCH,
1738 ISSET(tp->t_state, TS_CONNECTED) ?
1739 "ttyin" : "ttyhup", (int)slp);
1740 crit_exit();
1741 if (error == EWOULDBLOCK)
1742 error = 0;
1743 else if (error)
1744 return (error);
1745 /*
1746 * XXX what happens if another process eats some input
1747 * while we are asleep (not just here)? It would be
1748 * safest to detect changes and reset our state variables
1749 * (has_stime and last_cc).
1750 */
1751 slp = 0;
1752 goto loop;
1753 }
1754 read:
1755 crit_exit();
1756 /*
1757 * Input present, check for input mapping and processing.
1758 */
1759 first = 1;
1760 if (ISSET(lflag, ICANON | ISIG))
1761 goto slowcase;
1762 for (;;) {
1763 char ibuf[IBUFSIZ];
1764 int icc;
1765
1766 icc = (int)szmin(uio->uio_resid, IBUFSIZ);
1767 icc = q_to_b(qp, ibuf, icc);
1768 if (icc <= 0) {
1769 if (first)
1770 goto loop;
1771 break;
1772 }
1773 error = uiomove(ibuf, (size_t)icc, uio);
1774 /*
1775 * XXX if there was an error then we should ungetc() the
1776 * unmoved chars and reduce icc here.
1777 */
1778 if (error)
1779 break;
1780 if (uio->uio_resid == 0)
1781 break;
1782 first = 0;
1783 }
1784 goto out;
1785 slowcase:
1786 for (;;) {
1787 c = clist_getc(qp);
1788 if (c < 0) {
1789 if (first)
1790 goto loop;
1791 break;
1792 }
1793 /*
1794 * delayed suspend (^Y)
1795 */
1796 if (CCEQ(cc[VDSUSP], c) &&
1797 ISSET(lflag, IEXTEN | ISIG) == (IEXTEN | ISIG)) {
1798 pgsignal(tp->t_pgrp, SIGTSTP, 1);
1799 if (first) {
1800 error = ttysleep(tp, &lbolt, PCATCH,
1801 "ttybg3", 0);
1802 if (error)
1803 break;
1804 goto loop;
1805 }
1806 break;
1807 }
1808 /*
1809 * Interpret EOF only in canonical mode.
1810 */
1811 if (CCEQ(cc[VEOF], c) && ISSET(lflag, ICANON))
1812 break;
1813 /*
1814 * Give user character.
1815 */
1816 error = ureadc(c, uio);
1817 if (error)
1818 /* XXX should ungetc(c, qp). */
1819 break;
1820 if (uio->uio_resid == 0)
1821 break;
1822 /*
1823 * In canonical mode check for a "break character"
1824 * marking the end of a "line of input".
1825 */
1826 if (ISSET(lflag, ICANON) && TTBREAKC(c, lflag))
1827 break;
1828 first = 0;
1829 }
1830
1831 out:
1832 /*
1833 * Look to unblock input now that (presumably)
1834 * the input queue has gone down.
1835 */
1836 crit_enter();
1837 if (ISSET(tp->t_state, TS_TBLOCK) &&
1838 tp->t_rawq.c_cc + tp->t_canq.c_cc <= tp->t_ilowat)
1839 ttyunblock(tp);
1840 crit_exit();
1841
1842 return (error);
1843 }
1844
1845 /*
1846 * Check the output queue on tp for space for a kernel message (from uprintf
1847 * or tprintf). Allow some space over the normal hiwater mark so we don't
1848 * lose messages due to normal flow control, but don't let the tty run amok.
1849 * Sleeps here are not interruptible, but we return prematurely if new signals
1850 * arrive.
1851 */
1852 int
1853 ttycheckoutq(struct tty *tp, int wait)
1854 {
1855 struct lwp *lp = curthread->td_lwp;
1856 int hiwat;
1857 sigset_t oldset, newset;
1858
1859 hiwat = tp->t_ohiwat;
1860 SIGEMPTYSET(oldset);
1861 SIGEMPTYSET(newset);
1862 crit_enter();
1863 if (wait)
1864 oldset = lwp_sigpend(lp);
1865 if (tp->t_outq.c_cc > hiwat + OBUFSIZ + 100) {
1866 while (tp->t_outq.c_cc > hiwat) {
1867 ttstart(tp);
1868 if (tp->t_outq.c_cc <= hiwat)
1869 break;
1870 if (wait)
1871 newset = lwp_sigpend(lp);
1872 if (!wait || SIGSETNEQ(oldset, newset)) {
1873 crit_exit();
1874 return (0);
1875 }
1876 SET(tp->t_state, TS_SO_OLOWAT);
1877 tsleep(TSA_OLOWAT(tp), 0, "ttoutq", hz);
1878 }
1879 }
1880 crit_exit();
1881 return (1);
1882 }
1883
1884 /*
1885 * Process a write call on a tty device.
1886 */
1887 int
1888 ttwrite(struct tty *tp, struct uio *uio, int flag)
1889 {
1890 char *cp = NULL;
1891 int cc, ce;
1892 struct proc *pp;
1893 struct lwp *lp;
1894 int i, hiwat, error;
1895 size_t cnt;
1896
1897 char obuf[OBUFSIZ];
1898
1899 lp = curthread->td_lwp;
1900 hiwat = tp->t_ohiwat;
1901 cnt = uio->uio_resid;
1902 error = 0;
1903 cc = 0;
1904 loop:
1905 crit_enter();
1906 if (ISSET(tp->t_state, TS_ZOMBIE)) {
1907 crit_exit();
1908 if (uio->uio_resid == cnt)
1909 error = EIO;
1910 goto out;
1911 }
1912 if (!ISSET(tp->t_state, TS_CONNECTED)) {
1913 if (flag & IO_NDELAY) {
1914 crit_exit();
1915 error = EWOULDBLOCK;
1916 goto out;
1917 }
1918 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "ttydcd", 0);
1919 crit_exit();
1920 if (error)
1921 goto out;
1922 goto loop;
1923 }
1924 crit_exit();
1925
1926 /*
1927 * Hang the process if it's in the background.
1928 */
1929 if ((pp = curproc) && isbackground(pp, tp) &&
1930 ISSET(tp->t_lflag, TOSTOP) && !(pp->p_flag & P_PPWAIT) &&
1931 !SIGISMEMBER(pp->p_sigignore, SIGTTOU) &&
1932 !SIGISMEMBER(lp->lwp_sigmask, SIGTTOU)) {
1933 if (pp->p_pgrp->pg_jobc == 0) {
1934 error = EIO;
1935 goto out;
1936 }
1937 pgsignal(pp->p_pgrp, SIGTTOU, 1);
1938 error = ttysleep(tp, &lbolt, PCATCH, "ttybg4", 0);
1939 if (error)
1940 goto out;
1941 goto loop;
1942 }
1943 /*
1944 * Process the user's data in at most OBUFSIZ chunks. Perform any
1945 * output translation. Keep track of high water mark, sleep on
1946 * overflow awaiting device aid in acquiring new space.
1947 */
1948 while (uio->uio_resid > 0 || cc > 0) {
1949 if (ISSET(tp->t_lflag, FLUSHO)) {
1950 uio->uio_resid = 0;
1951 return (0);
1952 }
1953 if (tp->t_outq.c_cc > hiwat)
1954 goto ovhiwat;
1955 /*
1956 * Grab a hunk of data from the user, unless we have some
1957 * leftover from last time.
1958 */
1959 if (cc == 0) {
1960 cc = szmin(uio->uio_resid, OBUFSIZ);
1961 cp = obuf;
1962 error = uiomove(cp, (size_t)cc, uio);
1963 if (error) {
1964 cc = 0;
1965 break;
1966 }
1967 }
1968 /*
1969 * If nothing fancy need be done, grab those characters we
1970 * can handle without any of ttyoutput's processing and
1971 * just transfer them to the output q. For those chars
1972 * which require special processing (as indicated by the
1973 * bits in char_type), call ttyoutput. After processing
1974 * a hunk of data, look for FLUSHO so ^O's will take effect
1975 * immediately.
1976 */
1977 while (cc > 0) {
1978 if (!ISSET(tp->t_oflag, OPOST))
1979 ce = cc;
1980 else {
1981 ce = cc - scanc((u_int)cc, (u_char *)cp,
1982 char_type, CCLASSMASK);
1983 /*
1984 * If ce is zero, then we're processing
1985 * a special character through ttyoutput.
1986 */
1987 if (ce == 0) {
1988 tp->t_rocount = 0;
1989 if (ttyoutput(*cp, tp) >= 0) {
1990 /* No Clists, wait a bit. */
1991 ttstart(tp);
1992 if (flag & IO_NDELAY) {
1993 error = EWOULDBLOCK;
1994 goto out;
1995 }
1996 error = ttysleep(tp, &lbolt,
1997 PCATCH,
1998 "ttybf1", 0);
1999 if (error)
2000 goto out;
2001 goto loop;
2002 }
2003 cp++;
2004 cc--;
2005 if (ISSET(tp->t_lflag, FLUSHO) ||
2006 tp->t_outq.c_cc > hiwat)
2007 goto ovhiwat;
2008 continue;
2009 }
2010 }
2011 /*
2012 * A bunch of normal characters have been found.
2013 * Transfer them en masse to the output queue and
2014 * continue processing at the top of the loop.
2015 * If there are any further characters in this
2016 * <= OBUFSIZ chunk, the first should be a character
2017 * requiring special handling by ttyoutput.
2018 */
2019 tp->t_rocount = 0;
2020 i = b_to_q(cp, ce, &tp->t_outq);
2021 ce -= i;
2022 tp->t_column += ce;
2023 cp += ce, cc -= ce, tk_nout += ce;
2024 tp->t_outcc += ce;
2025 if (i > 0) {
2026 /* No Clists, wait a bit. */
2027 ttstart(tp);
2028 if (flag & IO_NDELAY) {
2029 error = EWOULDBLOCK;
2030 goto out;
2031 }
2032 error = ttysleep(tp, &lbolt, PCATCH,
2033 "ttybf2", 0);
2034 if (error)
2035 goto out;
2036 goto loop;
2037 }
2038 if (ISSET(tp->t_lflag, FLUSHO) ||
2039 tp->t_outq.c_cc > hiwat)
2040 break;
2041 }
2042 ttstart(tp);
2043 }
2044 out:
2045 /*
2046 * If cc is nonzero, we leave the uio structure inconsistent, as the
2047 * offset and iov pointers have moved forward, but it doesn't matter
2048 * (the call will either return short or restart with a new uio).
2049 */
2050 uio->uio_resid += cc;
2051 return (error);
2052
2053 ovhiwat:
2054 ttstart(tp);
2055 crit_enter();
2056 /*
2057 * This can only occur if FLUSHO is set in t_lflag,
2058 * or if ttstart/oproc is synchronous (or very fast).
2059 */
2060 if (tp->t_outq.c_cc <= hiwat) {
2061 crit_exit();
2062 goto loop;
2063 }
2064 if (flag & IO_NDELAY) {
2065 crit_exit();
2066 uio->uio_resid += cc;
2067 return (uio->uio_resid == cnt ? EWOULDBLOCK : 0);
2068 }
2069 SET(tp->t_state, TS_SO_OLOWAT);
2070 error = ttysleep(tp, TSA_OLOWAT(tp), PCATCH, "ttywri", tp->t_timeout);
2071 crit_exit();
2072 if (error == EWOULDBLOCK)
2073 error = EIO;
2074 if (error)
2075 goto out;
2076 goto loop;
2077 }
2078
2079 /*
2080 * Rubout one character from the rawq of tp
2081 * as cleanly as possible.
2082 */
2083 static void
2084 ttyrub(int c, struct tty *tp)
2085 {
2086 char *cp;
2087 int savecol;
2088 int tabc;
2089
2090 if (!ISSET(tp->t_lflag, ECHO) || ISSET(tp->t_lflag, EXTPROC))
2091 return;
2092 CLR(tp->t_lflag, FLUSHO);
2093 if (ISSET(tp->t_lflag, ECHOE)) {
2094 if (tp->t_rocount == 0) {
2095 /*
2096 * Screwed by ttwrite; retype
2097 */
2098 ttyretype(tp);
2099 return;
2100 }
2101 if (c == ('\t' | TTY_QUOTE) || c == ('\n' | TTY_QUOTE))
2102 ttyrubo(tp, 2);
2103 else {
2104 CLR(c, ~TTY_CHARMASK);
2105 switch (CCLASS(c)) {
2106 case ORDINARY:
2107 ttyrubo(tp, 1);
2108 break;
2109 case BACKSPACE:
2110 case CONTROL:
2111 case NEWLINE:
2112 case RETURN:
2113 case VTAB:
2114 if (ISSET(tp->t_lflag, ECHOCTL))
2115 ttyrubo(tp, 2);
2116 break;
2117 case TAB:
2118 if (tp->t_rocount < tp->t_rawq.c_cc) {
2119 ttyretype(tp);
2120 return;
2121 }
2122 crit_enter();
2123 savecol = tp->t_column;
2124 SET(tp->t_state, TS_CNTTB);
2125 SET(tp->t_lflag, FLUSHO);
2126 tp->t_column = tp->t_rocol;
2127 cp = tp->t_rawq.c_cf;
2128 if (cp)
2129 tabc = *cp; /* XXX FIX NEXTC */
2130 for (; cp; cp = nextc(&tp->t_rawq, cp, &tabc))
2131 ttyecho(tabc, tp);
2132 CLR(tp->t_lflag, FLUSHO);
2133 CLR(tp->t_state, TS_CNTTB);
2134 crit_exit();
2135
2136 /* savecol will now be length of the tab. */
2137 savecol -= tp->t_column;
2138 tp->t_column += savecol;
2139 if (savecol > 8)
2140 savecol = 8; /* overflow screw */
2141 while (--savecol >= 0)
2142 (void)ttyoutput('\b', tp);
2143 break;
2144 default: /* XXX */
2145 #define PANICSTR "ttyrub: would panic c = %d, val = %d\n"
2146 (void)kprintf(PANICSTR, c, CCLASS(c));
2147 #ifdef notdef
2148 panic(PANICSTR, c, CCLASS(c));
2149 #endif
2150 }
2151 }
2152 } else if (ISSET(tp->t_lflag, ECHOPRT)) {
2153 if (!ISSET(tp->t_state, TS_ERASE)) {
2154 SET(tp->t_state, TS_ERASE);
2155 (void)ttyoutput('\\', tp);
2156 }
2157 ttyecho(c, tp);
2158 } else {
2159 ttyecho(tp->t_cc[VERASE], tp);
2160 /*
2161 * This code may be executed not only when an ERASE key
2162 * is pressed, but also when ^U (KILL) or ^W (WERASE) are.
2163 * So, I didn't think it was worthwhile to pass the extra
2164 * information (which would need an extra parameter,
2165 * changing every call) needed to distinguish the ERASE2
2166 * case from the ERASE.
2167 */
2168 }
2169 --tp->t_rocount;
2170 }
2171
2172 /*
2173 * Back over cnt characters, erasing them.
2174 */
2175 static void
2176 ttyrubo(struct tty *tp, int cnt)
2177 {
2178
2179 while (cnt-- > 0) {
2180 (void)ttyoutput('\b', tp);
2181 (void)ttyoutput(' ', tp);
2182 (void)ttyoutput('\b', tp);
2183 }
2184 }
2185
2186 /*
2187 * ttyretype --
2188 * Reprint the rawq line. Note, it is assumed that c_cc has already
2189 * been checked.
2190 */
2191 static void
2192 ttyretype(struct tty *tp)
2193 {
2194 char *cp;
2195 int c;
2196
2197 /* Echo the reprint character. */
2198 if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
2199 ttyecho(tp->t_cc[VREPRINT], tp);
2200
2201 (void)ttyoutput('\n', tp);
2202
2203 /*
2204 * XXX
2205 * FIX: NEXTC IS BROKEN - DOESN'T CHECK QUOTE
2206 * BIT OF FIRST CHAR.
2207 */
2208 crit_enter();
2209 for (cp = tp->t_canq.c_cf, c = (cp != NULL ? *cp : 0);
2210 cp != NULL; cp = nextc(&tp->t_canq, cp, &c))
2211 ttyecho(c, tp);
2212 for (cp = tp->t_rawq.c_cf, c = (cp != NULL ? *cp : 0);
2213 cp != NULL; cp = nextc(&tp->t_rawq, cp, &c))
2214 ttyecho(c, tp);
2215 CLR(tp->t_state, TS_ERASE);
2216 crit_exit();
2217
2218 tp->t_rocount = tp->t_rawq.c_cc;
2219 tp->t_rocol = 0;
2220 }
2221
2222 /*
2223 * Echo a typed character to the terminal.
2224 */
2225 static void
2226 ttyecho(int c, struct tty *tp)
2227 {
2228
2229 if (!ISSET(tp->t_state, TS_CNTTB))
2230 CLR(tp->t_lflag, FLUSHO);
2231 if ((!ISSET(tp->t_lflag, ECHO) &&
2232 (c != '\n' || !ISSET(tp->t_lflag, ECHONL))) ||
2233 ISSET(tp->t_lflag, EXTPROC))
2234 return;
2235 if (ISSET(tp->t_lflag, ECHOCTL) &&
2236 ((ISSET(c, TTY_CHARMASK) <= 037 && c != '\t' && c != '\n') ||
2237 ISSET(c, TTY_CHARMASK) == 0177)) {
2238 (void)ttyoutput('^', tp);
2239 CLR(c, ~TTY_CHARMASK);
2240 if (c == 0177)
2241 c = '?';
2242 else
2243 c += 'A' - 1;
2244 }
2245 (void)ttyoutput(c, tp);
2246 }
2247
2248 /*
2249 * Wake up any readers on a tty.
2250 */
2251 void
2252 ttwakeup(struct tty *tp)
2253 {
2254
2255 if (tp->t_rsel.si_pid != 0)
2256 selwakeup(&tp->t_rsel);
2257 if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
2258 pgsigio(tp->t_sigio, SIGIO, (tp->t_session != NULL));
2259 wakeup(TSA_HUP_OR_INPUT(tp));
2260 KNOTE(&tp->t_rsel.si_note, 0);
2261 }
2262
2263 /*
2264 * Wake up any writers on a tty.
2265 */
2266 void
2267 ttwwakeup(struct tty *tp)
2268 {
2269
2270 if (tp->t_wsel.si_pid != 0 && tp->t_outq.c_cc <= tp->t_olowat)
2271 selwakeup(&tp->t_wsel);
2272 if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
2273 pgsigio(tp->t_sigio, SIGIO, (tp->t_session != NULL));
2274 if (ISSET(tp->t_state, TS_BUSY | TS_SO_OCOMPLETE) ==
2275 TS_SO_OCOMPLETE && tp->t_outq.c_cc == 0) {
2276 CLR(tp->t_state, TS_SO_OCOMPLETE);
2277 wakeup(TSA_OCOMPLETE(tp));
2278 }
2279 if (ISSET(tp->t_state, TS_SO_OLOWAT) &&
2280 tp->t_outq.c_cc <= tp->t_olowat) {
2281 CLR(tp->t_state, TS_SO_OLOWAT);
2282 wakeup(TSA_OLOWAT(tp));
2283 }
2284 KNOTE(&tp->t_wsel.si_note, 0);
2285 }
2286
2287 /*
2288 * Look up a code for a specified speed in a conversion table;
2289 * used by drivers to map software speed values to hardware parameters.
2290 */
2291 int
2292 ttspeedtab(int speed, struct speedtab *table)
2293 {
2294
2295 for ( ; table->sp_speed != -1; table++)
2296 if (table->sp_speed == speed)
2297 return (table->sp_code);
2298 return (-1);
2299 }
2300
2301 /*
2302 * Set input and output watermarks and buffer sizes. For input, the
2303 * high watermark is about one second's worth of input above empty, the
2304 * low watermark is slightly below high water, and the buffer size is a
2305 * driver-dependent amount above high water. For output, the watermarks
2306 * are near the ends of the buffer, with about 1 second's worth of input
2307 * between them. All this only applies to the standard line discipline.
2308 */
2309 void
2310 ttsetwater(struct tty *tp)
2311 {
2312 int cps, ttmaxhiwat, x;
2313
2314 /* Input. */
2315 clist_alloc_cblocks(&tp->t_canq, TTYHOG, 512);
2316 switch (tp->t_ispeedwat) {
2317 case (speed_t)-1:
2318 cps = tp->t_ispeed / 10;
2319 break;
2320 case 0:
2321 /*
2322 * This case is for old drivers that don't know about
2323 * t_ispeedwat. Arrange for them to get the old buffer
2324 * sizes and watermarks.
2325 */
2326 cps = TTYHOG - 2 * 256;
2327 tp->t_ififosize = 2 * 2048;
2328 break;
2329 default:
2330 cps = tp->t_ispeedwat / 10;
2331 break;
2332 }
2333 tp->t_ihiwat = cps;
2334 tp->t_ilowat = 7 * cps / 8;
2335 x = cps + tp->t_ififosize;
2336 clist_alloc_cblocks(&tp->t_rawq, x, x);
2337
2338 /* Output. */
2339 switch (tp->t_ospeedwat) {
2340 case (speed_t)-1:
2341 cps = tp->t_ospeed / 10;
2342 ttmaxhiwat = 2 * TTMAXHIWAT;
2343 break;
2344 case 0:
2345 cps = tp->t_ospeed / 10;
2346 ttmaxhiwat = TTMAXHIWAT;
2347 break;
2348 default:
2349 cps = tp->t_ospeedwat / 10;
2350 ttmaxhiwat = 8 * TTMAXHIWAT;
2351 break;
2352 }
2353 #define CLAMP(x, h, l) ((x) > h ? h : ((x) < l) ? l : (x))
2354 tp->t_olowat = x = CLAMP(cps / 2, TTMAXLOWAT, TTMINLOWAT);
2355 x += cps;
2356 x = CLAMP(x, ttmaxhiwat, TTMINHIWAT); /* XXX clamps are too magic */
2357 tp->t_ohiwat = roundup(x, CBSIZE); /* XXX for compat */
2358 x = imax(tp->t_ohiwat, TTMAXHIWAT); /* XXX for compat/safety */
2359 x += OBUFSIZ + 100;
2360 clist_alloc_cblocks(&tp->t_outq, x, x);
2361 #undef CLAMP
2362 }
2363
2364 /*
2365 * Report on state of foreground process group.
2366 */
2367 void
2368 ttyinfo(struct tty *tp)
2369 {
2370 struct proc *p, *pick;
2371 struct lwp *lp;
2372 struct rusage ru;
2373 int tmp;
2374
2375 if (ttycheckoutq(tp,0) == 0)
2376 return;
2377
2378 /*
2379 * We always print the load average, then figure out what else to
2380 * print based on the state of the current process group.
2381 */
2382 tmp = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
2383 ttyprintf(tp, "load: %d.%02d ", tmp / 100, tmp % 100);
2384
2385 if (tp->t_session == NULL) {
2386 ttyprintf(tp, "not a controlling terminal\n");
2387 } else if (tp->t_pgrp == NULL) {
2388 ttyprintf(tp, "no foreground process group\n");
2389 } else if ((p = LIST_FIRST(&tp->t_pgrp->pg_members)) == 0) {
2390 ttyprintf(tp, "empty foreground process group\n");
2391 } else {
2392 /*
2393 * Pick an interesting process. Note that certain elements,
2394 * in particular the wmesg, require a critical section for
2395 * safe access (YYY and we are still not MP safe).
2396 *
2397 * NOTE: lwp_wmesg is lwp_thread->td_wmesg.
2398 */
2399 char buf[64];
2400 const char *str;
2401 long vmsz;
2402 int pctcpu;
2403
2404 crit_enter();
2405
2406 /* XXX lwp should compare lwps */
2407
2408 for (pick = NULL; p != 0; p = LIST_NEXT(p, p_pglist)) {
2409 if (proc_compare(pick, p))
2410 pick = p;
2411 }
2412
2413 /* XXX lwp */
2414 lp = FIRST_LWP_IN_PROC(pick);
2415 if (lp == NULL) {
2416 ttyprintf(tp, "foreground process without lwp\n");
2417 tp->t_rocount = 0;
2418 crit_exit();
2419 return;
2420 }
2421
2422 /*
2423 * Figure out what wait/process-state message, and command
2424 * buffer to present
2425 */
2426 /*
2427 * XXX lwp This is a horrible mixture. We need to rework this
2428 * as soon as lwps have their own runnable status.
2429 */
2430 if (pick->p_flag & P_WEXIT)
2431 str = "exiting";
2432 else if (lp->lwp_stat == LSRUN)
2433 str = "running";
2434 else if (pick->p_stat == SIDL)
2435 str = "spawning";
2436 else if (lp->lwp_wmesg) /* lwp_thread must not be NULL */
2437 str = lp->lwp_wmesg;
2438 else
2439 str = "iowait";
2440
2441 ksnprintf(buf, sizeof(buf), "cmd: %s %d [%s]",
2442 pick->p_comm, pick->p_pid, str);
2443
2444 /*
2445 * Calculate cpu usage, percent cpu, and cmsz. Note that
2446 * 'pick' becomes invalid the moment we exit the critical
2447 * section.
2448 */
2449 if (lp->lwp_thread && (pick->p_flag & P_SWAPPEDOUT) == 0)
2450 calcru_proc(pick, &ru);
2451
2452 pctcpu = (lp->lwp_pctcpu * 10000 + FSCALE / 2) >> FSHIFT;
2453
2454 if (pick->p_stat == SIDL || pick->p_stat == SZOMB)
2455 vmsz = 0;
2456 else
2457 vmsz = pgtok(vmspace_resident_count(pick->p_vmspace));
2458
2459 crit_exit();
2460
2461 /*
2462 * Dump the output
2463 */
2464 ttyprintf(tp, " %s ", buf);
2465 ttyprintf(tp, "%ld.%02ldu ",
2466 ru.ru_utime.tv_sec, ru.ru_utime.tv_usec / 10000);
2467 ttyprintf(tp, "%ld.%02lds ",
2468 ru.ru_stime.tv_sec, ru.ru_stime.tv_usec / 10000);
2469 ttyprintf(tp, "%d%% %ldk\n", pctcpu / 100, vmsz);
2470 }
2471 tp->t_rocount = 0; /* so pending input will be retyped if BS */
2472 }
2473
2474 /*
2475 * Returns 1 if p2 is "better" than p1
2476 *
2477 * The algorithm for picking the "interesting" process is thus:
2478 *
2479 * 1) Only foreground processes are eligible - implied.
2480 * 2) Runnable processes are favored over anything else. The runner
2481 * with the highest cpu utilization is picked (p_cpticks). Ties are
2482 * broken by picking the highest pid.
2483 * 3) The sleeper with the shortest sleep time is next. With ties,
2484 * we pick out just "short-term" sleepers (LWP_SINTR == 0).
2485 * 4) Further ties are broken by picking the highest pid.
2486 */
2487 #define ISRUN(lp) ((lp)->lwp_stat == LSRUN)
2488 #define TESTAB(a, b) ((a)<<1 | (b))
2489 #define ONLYA 2
2490 #define ONLYB 1
2491 #define BOTH 3
2492
2493 static int
2494 proc_compare(struct proc *p1, struct proc *p2)
2495 {
2496 struct lwp *lp1, *lp2;
2497 if (p1 == NULL)
2498 return (1);
2499
2500 /*
2501 * weed out zombies
2502 */
2503 switch (TESTAB(p1->p_stat == SZOMB, p2->p_stat == SZOMB)) {
2504 case ONLYA:
2505 return (1);
2506 case ONLYB:
2507 return (0);
2508 case BOTH:
2509 return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
2510 }
2511
2512 /* XXX lwp */
2513 lp1 = FIRST_LWP_IN_PROC(p1);
2514 lp2 = FIRST_LWP_IN_PROC(p2);
2515
2516 /*
2517 * see if at least one of them is runnable
2518 */
2519 switch (TESTAB(ISRUN(lp1), ISRUN(lp2))) {
2520 case ONLYA:
2521 return (0);
2522 case ONLYB:
2523 return (1);
2524 case BOTH:
2525 /*
2526 * tie - favor one with highest recent cpu utilization
2527 */
2528 if (lp2->lwp_cpticks > lp1->lwp_cpticks)
2529 return (1);
2530 if (lp1->lwp_cpticks > lp2->lwp_cpticks)
2531 return (0);
2532 return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
2533 }
2534 /*
2535 * pick the one with the smallest sleep time
2536 */
2537 if (lp2->lwp_slptime > lp1->lwp_slptime)
2538 return (0);
2539 if (lp1->lwp_slptime > lp2->lwp_slptime)
2540 return (1);
2541 /*
2542 * favor one sleeping in a non-interruptible sleep
2543 */
2544 if (lp1->lwp_flag & LWP_SINTR && (lp2->lwp_flag & LWP_SINTR) == 0)
2545 return (1);
2546 if (lp2->lwp_flag & LWP_SINTR && (lp1->lwp_flag & LWP_SINTR) == 0)
2547 return (0);
2548 return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
2549 }
2550
2551 /*
2552 * Output char to tty; console putchar style.
2553 */
2554 int
2555 tputchar(int c, struct tty *tp)
2556 {
2557 crit_enter();
2558 if (!ISSET(tp->t_state, TS_CONNECTED)) {
2559 crit_exit();
2560 return (-1);
2561 }
2562 if (c == '\n')
2563 (void)ttyoutput('\r', tp);
2564 (void)ttyoutput(c, tp);
2565 ttstart(tp);
2566 crit_exit();
2567 return (0);
2568 }
2569
2570 /*
2571 * Sleep on chan, returning ERESTART if tty changed while we napped and
2572 * returning any errors (e.g. EINTR/EWOULDBLOCK) reported by tsleep. If
2573 * the tty is revoked, restarting a pending call will redo validation done
2574 * at the start of the call.
2575 */
2576 int
2577 ttysleep(struct tty *tp, void *chan, int slpflags, char *wmesg, int timo)
2578 {
2579 int error;
2580 int gen;
2581
2582 gen = tp->t_gen;
2583 error = tsleep(chan, slpflags, wmesg, timo);
2584 if (error)
2585 return (error);
2586 return (tp->t_gen == gen ? 0 : ERESTART);
2587 }
2588
2589 /*
2590 * Revoke a tty.
2591 *
2592 * We bump the gen to force any ttysleep()'s to return with ERESTART
2593 * and flush the tty. The related fp's should already have been
2594 * replaced so the tty will close when the last references on the
2595 * original fp's go away.
2596 */
2597 int
2598 ttyrevoke(struct dev_revoke_args *ap)
2599 {
2600 struct tty *tp;
2601
2602 tp = ap->a_head.a_dev->si_tty;
2603 tp->t_gen++;
2604 ttyflush(tp, FREAD | FWRITE);
2605 wakeup(TSA_CARR_ON(tp));
2606 ttwakeup(tp);
2607 ttwwakeup(tp);
2608 return (0);
2609 }
2610
2611 /*
2612 * Allocate a tty struct. Clists in the struct will be allocated by
2613 * ttyopen().
2614 */
2615 struct tty *
2616 ttymalloc(struct tty *tp)
2617 {
2618
2619 if (tp) {
2620 return(tp);
2621 }
2622 tp = kmalloc(sizeof *tp, M_TTYS, M_WAITOK|M_ZERO);
2623 ttyregister(tp);
2624 return (tp);
2625 }
2626
2627 #if 0
2628 /*
2629 * Free a tty struct. Clists in the struct should have been freed by
2630 * ttyclose().
2631 *
2632 * XXX not yet usable: since we support a half-closed state and do not
2633 * ref count the tty reference from the session, it is possible for a
2634 * session to hold a ref on the tty. See TTY_DO_FULL_CLOSE.
2635 */
2636 void
2637 ttyfree(struct tty *tp)
2638 {
2639 kfree(tp, M_TTYS);
2640 }
2641 #endif /* 0 */
2642
2643 void
2644 ttyregister(struct tty *tp)
2645 {
2646 SLIST_INSERT_HEAD(&tty_list, tp, t_list);
2647 }
2648
2649 static int
2650 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
2651 {
2652 int error;
2653 struct tty *tp, t;
2654 SLIST_FOREACH(tp, &tty_list, t_list) {
2655 t = *tp;
2656 if (t.t_dev)
2657 t.t_dev = (cdev_t)(uintptr_t)dev2udev(t.t_dev);
2658 error = SYSCTL_OUT(req, (caddr_t)&t, sizeof(t));
2659 if (error)
2660 return (error);
2661 }
2662 return (0);
2663 }
2664
2665 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD,
2666 0, 0, sysctl_kern_ttys, "S,tty", "All struct ttys");
2667
2668 void
2669 nottystop(struct tty *tp, int rw)
2670 {
2671
2672 return;
2673 }
2674
2675 int
2676 ttyread(struct dev_read_args *ap)
2677 {
2678 struct tty *tp;
2679
2680 tp = ap->a_head.a_dev->si_tty;
2681 if (tp == NULL)
2682 return (ENODEV);
2683 return ((*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag));
2684 }
2685
2686 int
2687 ttywrite(struct dev_write_args *ap)
2688 {
2689 struct tty *tp;
2690
2691 tp = ap->a_head.a_dev->si_tty;
2692 if (tp == NULL)
2693 return (ENODEV);
2694 return ((*linesw[tp->t_line].l_write)(tp, ap->a_uio, ap->a_ioflag));
2695 }
DragonFly BSD