kernel - Fix pty registration, memory leak
[dragonfly.git] / sys / kern / tty.c
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.
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7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
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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.
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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/kernel.h>
90 #include <sys/vnode.h>
91 #include <sys/signalvar.h>
92 #include <sys/signal2.h>
93 #include <sys/resourcevar.h>
94 #include <sys/malloc.h>
95 #include <sys/filedesc.h>
96 #include <sys/sysctl.h>
97 #include <sys/thread2.h>
98
99 #include <vm/vm.h>
100 #include <sys/lock.h>
101 #include <vm/pmap.h>
102 #include <vm/vm_map.h>
103
104 MALLOC_DEFINE(M_TTYS, "ttys", "tty data structures");
105
106 static int      proc_compare (struct proc *p1, struct proc *p2);
107 static int      ttnread (struct tty *tp);
108 static void     ttyecho (int c, struct tty *tp);
109 static int      ttyoutput (int c, struct tty *tp);
110 static void     ttypend (struct tty *tp);
111 static void     ttyretype (struct tty *tp);
112 static void     ttyrub (int c, struct tty *tp);
113 static void     ttyrubo (struct tty *tp, int cnt);
114 static void     ttyunblock (struct tty *tp);
115 static int      ttywflush (struct tty *tp);
116 static int      filt_ttyread (struct knote *kn, long hint);
117 static void     filt_ttyrdetach (struct knote *kn);
118 static int      filt_ttywrite (struct knote *kn, long hint);
119 static void     filt_ttywdetach (struct knote *kn);
120
121 /*
122  * Table with character classes and parity. The 8th bit indicates parity,
123  * the 7th bit indicates the character is an alphameric or underscore (for
124  * ALTWERASE), and the low 6 bits indicate delay type.  If the low 6 bits
125  * are 0 then the character needs no special processing on output; classes
126  * other than 0 might be translated or (not currently) require delays.
127  */
128 #define E       0x00    /* Even parity. */
129 #define O       0x80    /* Odd parity. */
130 #define PARITY(c)       (char_type[c] & O)
131
132 #define ALPHA   0x40    /* Alpha or underscore. */
133 #define ISALPHA(c)      (char_type[(c) & TTY_CHARMASK] & ALPHA)
134
135 #define CCLASSMASK      0x3f
136 #define CCLASS(c)       (char_type[c] & CCLASSMASK)
137
138 #define BS      BACKSPACE
139 #define CC      CONTROL
140 #define CR      RETURN
141 #define NA      ORDINARY | ALPHA
142 #define NL      NEWLINE
143 #define NO      ORDINARY
144 #define TB      TAB
145 #define VT      VTAB
146
147 static u_char const char_type[] = {
148         E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* nul - bel */
149         O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC, /* bs - si */
150         O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC, /* dle - etb */
151         E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* can - us */
152         O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* sp - ' */
153         E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO, /* ( - / */
154         E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* 0 - 7 */
155         O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* 8 - ? */
156         O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* @ - G */
157         E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* H - O */
158         E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* P - W */
159         O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA, /* X - _ */
160         E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* ` - g */
161         O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* h - o */
162         O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* p - w */
163         E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC, /* x - del */
164         /*
165          * Meta chars; should be settable per character set;
166          * for now, treat them all as normal characters.
167          */
168         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
169         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
170         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
171         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
172         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
173         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
174         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
175         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
176         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
177         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
178         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
179         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
180         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
181         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
182         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
183         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
184 };
185 #undef  BS
186 #undef  CC
187 #undef  CR
188 #undef  NA
189 #undef  NL
190 #undef  NO
191 #undef  TB
192 #undef  VT
193
194 /* Macros to clear/set/test flags. */
195 #define SET(t, f)       (t) |= (f)
196 #define CLR(t, f)       (t) &= ~(f)
197 #define ISSET(t, f)     ((t) & (f))
198
199 #undef MAX_INPUT                /* XXX wrong in <sys/syslimits.h> */
200 #define MAX_INPUT       TTYHOG  /* XXX limit is usually larger for !ICANON */
201
202 uint64_t tk_nin;
203 SYSCTL_OPAQUE(_kern, OID_AUTO, tk_nin, CTLFLAG_RD, &tk_nin, sizeof(tk_nin),
204     "LU", "TTY input statistic");
205 uint64_t tk_nout;
206 SYSCTL_OPAQUE(_kern, OID_AUTO, tk_nout, CTLFLAG_RD, &tk_nout, sizeof(tk_nout),
207     "LU", "TTY output statistic");
208 uint64_t tk_rawcc;
209
210 /*
211  * list of struct tty where pstat(8) can pick it up with sysctl
212  */
213 static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
214
215 /*
216  * Initial open of tty, or (re)entry to standard tty line discipline.
217  */
218 int
219 ttyopen(cdev_t device, struct tty *tp)
220 {
221         crit_enter();
222         tp->t_dev = device;
223         if (!ISSET(tp->t_state, TS_ISOPEN)) {
224                 SET(tp->t_state, TS_ISOPEN);
225                 if (ISSET(tp->t_cflag, CLOCAL)) {
226                         SET(tp->t_state, TS_CONNECTED);
227                 }
228                 bzero(&tp->t_winsize, sizeof(tp->t_winsize));
229         }
230         ttsetwater(tp);
231         crit_exit();
232         return (0);
233 }
234
235 /*
236  * Handle close() on a tty line: flush and set to initial state,
237  * bumping generation number so that pending read/write calls
238  * can detect recycling of the tty.
239  *
240  * XXX our caller should have done `spltty(); l_close(); ttyclose();'
241  * and l_close() should have flushed, but we repeat the spltty() and
242  * the flush in case there are buggy callers.
243  */
244 int
245 ttyclose(struct tty *tp)
246 {
247         funsetown(tp->t_sigio);
248         crit_enter();
249         if (constty == tp)
250                 constty = NULL;
251
252         ttyflush(tp, FREAD | FWRITE);
253         clist_free_cblocks(&tp->t_canq);
254         clist_free_cblocks(&tp->t_outq);
255         clist_free_cblocks(&tp->t_rawq);
256
257         tp->t_gen++;
258         tp->t_line = TTYDISC;
259         ttyclearsession(tp);
260         tp->t_state &= TS_REGISTERED;   /* clear all bits except */
261         crit_exit();
262         return (0);
263 }
264
265 /*
266  * Disassociate the tty from its session.  Traditionally this has only been
267  * a half-close, meaning that the session was still allowed to point at the
268  * tty (resulting in the tty in the ps command showing something like 'p0-'),
269  * even though the tty is no longer pointing at the session.
270  *
271  * The half close seems to be useful only for 'ps' output but there is as
272  * yet no reason to remove the feature.  The full-close code is currently
273  * #if 0'd out.  See also sess_rele() in kern/kern_proc.c.
274  */
275 void
276 ttyclearsession(struct tty *tp)
277 {
278         struct session *sp;
279
280         tp->t_pgrp = NULL;
281         if ((sp = tp->t_session) != NULL) {
282                 tp->t_session = NULL;
283 #ifdef TTY_DO_FULL_CLOSE
284                 /* FULL CLOSE (not yet) */
285                 if (sp->s_ttyp == tp) {
286                         sp->s_ttyp = NULL;
287                 } else {
288                         kprintf("ttyclearsession: warning: sp->s_ttyp != tp "
289                                 "%p/%p\n", sp->s_ttyp, tp);
290                 }
291 #endif
292         }
293 }
294
295 /*
296  * Release the tty vnode association for a session.  This is the 
297  * 'other half' of the close.  Because multiple opens of /dev/tty
298  * only generate a single open to the actual tty, the file modes
299  * are locked to FREAD|FWRITE.
300  *
301  * If dorevoke is non-zero, the session is also revoked.  We have to
302  * close the vnode if VCTTYISOPEN is set.
303  */
304 void
305 ttyclosesession(struct session *sp, int dorevoke)
306 {
307         struct vnode *vp;
308
309 retry:
310         /*
311          * There may not be a controlling terminal or it may have been closed
312          * out from under us.
313          */
314         if ((vp = sp->s_ttyvp) == NULL)
315                 return;
316
317         /*
318          * We need a lock if we have to close or revoke.
319          */
320         if ((vp->v_flag & VCTTYISOPEN) || dorevoke) {
321                 vhold(vp);
322                 if (vn_lock(vp, LK_EXCLUSIVE|LK_RETRY)) {
323                         vdrop(vp);
324                         goto retry;
325                 }
326
327                 /*
328                  * Retry if the vnode was ripped out from under us
329                  */
330                 if (vp != sp->s_ttyvp) {
331                         vn_unlock(vp);
332                         vdrop(vp);
333                         goto retry;
334                 }
335
336                 /*
337                  * Close and revoke as needed
338                  */
339                 sp->s_ttyvp = NULL;
340                 if (vp->v_flag & VCTTYISOPEN) {
341                         vclrflags(vp, VCTTYISOPEN);
342                         VOP_CLOSE(vp, FREAD|FWRITE);
343                 }
344                 vn_unlock(vp);
345                 if (dorevoke)
346                         vrevoke(vp, proc0.p_ucred);
347                 vdrop(vp);
348         } else {
349                 sp->s_ttyvp = NULL;
350         }
351         vrele(vp);
352 }
353
354 #define FLUSHQ(q) {                                                     \
355         if ((q)->c_cc)                                                  \
356                 ndflush(q, (q)->c_cc);                                  \
357 }
358
359 /* Is 'c' a line delimiter ("break" character)? */
360 #define TTBREAKC(c, lflag)                                                      \
361         ((c) == '\n' || (((c) == cc[VEOF] ||                            \
362           (c) == cc[VEOL] || ((c) == cc[VEOL2] && lflag & IEXTEN)) &&   \
363          (c) != _POSIX_VDISABLE))
364
365 /*
366  * Process input of a single character received on a tty.
367  */
368 int
369 ttyinput(int c, struct tty *tp)
370 {
371         tcflag_t iflag, lflag;
372         cc_t *cc;
373         int i, err;
374
375         /*
376          * If input is pending take it first.
377          */
378         lflag = tp->t_lflag;
379         if (ISSET(lflag, PENDIN))
380                 ttypend(tp);
381         /*
382          * Gather stats.
383          */
384         if (ISSET(lflag, ICANON))
385                 ++tp->t_cancc;
386         else
387                 ++tp->t_rawcc;
388         ++tk_nin;
389
390         /*
391          * Block further input iff:
392          * current input > threshold AND input is available to user program
393          * AND input flow control is enabled and not yet invoked.
394          * The 3 is slop for PARMRK.
395          */
396         iflag = tp->t_iflag;
397         if (tp->t_rawq.c_cc + tp->t_canq.c_cc > tp->t_ihiwat - 3 &&
398             (!ISSET(lflag, ICANON) || tp->t_canq.c_cc != 0) &&
399             (ISSET(tp->t_cflag, CRTS_IFLOW) || ISSET(iflag, IXOFF)) &&
400             !ISSET(tp->t_state, TS_TBLOCK))
401                 ttyblock(tp);
402
403         /* Handle exceptional conditions (break, parity, framing). */
404         cc = tp->t_cc;
405         err = (ISSET(c, TTY_ERRORMASK));
406         if (err) {
407                 CLR(c, TTY_ERRORMASK);
408                 if (ISSET(err, TTY_BI)) {
409                         if (ISSET(iflag, IGNBRK))
410                                 return (0);
411                         if (ISSET(iflag, BRKINT)) {
412                                 ttyflush(tp, FREAD | FWRITE);
413                                 pgsignal(tp->t_pgrp, SIGINT, 1);
414                                 goto endcase;
415                         }
416                         if (ISSET(iflag, PARMRK))
417                                 goto parmrk;
418                 } else if ((ISSET(err, TTY_PE) && ISSET(iflag, INPCK))
419                         || ISSET(err, TTY_FE)) {
420                         if (ISSET(iflag, IGNPAR))
421                                 return (0);
422                         else if (ISSET(iflag, PARMRK)) {
423 parmrk:
424                                 if (tp->t_rawq.c_cc + tp->t_canq.c_cc >
425                                     MAX_INPUT - 3)
426                                         goto input_overflow;
427                                 clist_putc(0377 | TTY_QUOTE, &tp->t_rawq);
428                                 clist_putc(0 | TTY_QUOTE, &tp->t_rawq);
429                                 clist_putc(c | TTY_QUOTE, &tp->t_rawq);
430                                 goto endcase;
431                         } else
432                                 c = 0;
433                 }
434         }
435
436         if (!ISSET(tp->t_state, TS_TYPEN) && ISSET(iflag, ISTRIP))
437                 CLR(c, 0x80);
438         if (!ISSET(lflag, EXTPROC)) {
439                 /*
440                  * Check for literal nexting very first
441                  */
442                 if (ISSET(tp->t_state, TS_LNCH)) {
443                         SET(c, TTY_QUOTE);
444                         CLR(tp->t_state, TS_LNCH);
445                 }
446                 /*
447                  * Scan for special characters.  This code
448                  * is really just a big case statement with
449                  * non-constant cases.  The bottom of the
450                  * case statement is labeled ``endcase'', so goto
451                  * it after a case match, or similar.
452                  */
453
454                 /*
455                  * Control chars which aren't controlled
456                  * by ICANON, ISIG, or IXON.
457                  */
458                 if (ISSET(lflag, IEXTEN)) {
459                         if (CCEQ(cc[VLNEXT], c)) {
460                                 if (ISSET(lflag, ECHO)) {
461                                         if (ISSET(lflag, ECHOE)) {
462                                                 (void)ttyoutput('^', tp);
463                                                 (void)ttyoutput('\b', tp);
464                                         } else
465                                                 ttyecho(c, tp);
466                                 }
467                                 SET(tp->t_state, TS_LNCH);
468                                 goto endcase;
469                         }
470                         if (CCEQ(cc[VDISCARD], c)) {
471                                 if (ISSET(lflag, FLUSHO))
472                                         CLR(tp->t_lflag, FLUSHO);
473                                 else {
474                                         ttyflush(tp, FWRITE);
475                                         ttyecho(c, tp);
476                                         if (tp->t_rawq.c_cc + tp->t_canq.c_cc)
477                                                 ttyretype(tp);
478                                         SET(tp->t_lflag, FLUSHO);
479                                 }
480                                 goto startoutput;
481                         }
482                 }
483                 /*
484                  * Signals.
485                  */
486                 if (ISSET(lflag, ISIG)) {
487                         if (CCEQ(cc[VINTR], c) || CCEQ(cc[VQUIT], c)) {
488                                 if (!ISSET(lflag, NOFLSH))
489                                         ttyflush(tp, FREAD | FWRITE);
490                                 ttyecho(c, tp);
491                                 pgsignal(tp->t_pgrp,
492                                     CCEQ(cc[VINTR], c) ? SIGINT : SIGQUIT, 1);
493                                 goto endcase;
494                         }
495                         if (CCEQ(cc[VSUSP], c)) {
496                                 if (!ISSET(lflag, NOFLSH))
497                                         ttyflush(tp, FREAD);
498                                 ttyecho(c, tp);
499                                 pgsignal(tp->t_pgrp, SIGTSTP, 1);
500                                 goto endcase;
501                         }
502                 }
503                 /*
504                  * Handle start/stop characters.
505                  */
506                 if (ISSET(iflag, IXON)) {
507                         if (CCEQ(cc[VSTOP], c)) {
508                                 if (!ISSET(tp->t_state, TS_TTSTOP)) {
509                                         SET(tp->t_state, TS_TTSTOP);
510                                         (*tp->t_stop)(tp, 0);
511                                         return (0);
512                                 }
513                                 if (!CCEQ(cc[VSTART], c))
514                                         return (0);
515                                 /*
516                                  * if VSTART == VSTOP then toggle
517                                  */
518                                 goto endcase;
519                         }
520                         if (CCEQ(cc[VSTART], c))
521                                 goto restartoutput;
522                 }
523                 /*
524                  * IGNCR, ICRNL, & INLCR
525                  */
526                 if (c == '\r') {
527                         if (ISSET(iflag, IGNCR))
528                                 return (0);
529                         else if (ISSET(iflag, ICRNL))
530                                 c = '\n';
531                 } else if (c == '\n' && ISSET(iflag, INLCR))
532                         c = '\r';
533         }
534         if (!ISSET(tp->t_lflag, EXTPROC) && ISSET(lflag, ICANON)) {
535                 /*
536                  * From here on down canonical mode character
537                  * processing takes place.
538                  */
539                 /*
540                  * erase or erase2 (^H / ^?)
541                  */
542                 if (CCEQ(cc[VERASE], c) || CCEQ(cc[VERASE2], c) ) {
543                         if (tp->t_rawq.c_cc)
544                                 ttyrub(clist_unputc(&tp->t_rawq), tp);
545                         goto endcase;
546                 }
547                 /*
548                  * kill (^U)
549                  */
550                 if (CCEQ(cc[VKILL], c)) {
551                         if (ISSET(lflag, ECHOKE) &&
552                             tp->t_rawq.c_cc == tp->t_rocount &&
553                             !ISSET(lflag, ECHOPRT))
554                                 while (tp->t_rawq.c_cc)
555                                         ttyrub(clist_unputc(&tp->t_rawq), tp);
556                         else {
557                                 ttyecho(c, tp);
558                                 if (ISSET(lflag, ECHOK) ||
559                                     ISSET(lflag, ECHOKE))
560                                         ttyecho('\n', tp);
561                                 FLUSHQ(&tp->t_rawq);
562                                 tp->t_rocount = 0;
563                         }
564                         CLR(tp->t_state, TS_LOCAL);
565                         goto endcase;
566                 }
567                 /*
568                  * word erase (^W)
569                  */
570                 if (CCEQ(cc[VWERASE], c) && ISSET(lflag, IEXTEN)) {
571                         int ctype;
572
573                         /*
574                          * erase whitespace
575                          */
576                         while ((c = clist_unputc(&tp->t_rawq)) == ' ' || c == '\t')
577                                 ttyrub(c, tp);
578                         if (c == -1)
579                                 goto endcase;
580                         /*
581                          * erase last char of word and remember the
582                          * next chars type (for ALTWERASE)
583                          */
584                         ttyrub(c, tp);
585                         c = clist_unputc(&tp->t_rawq);
586                         if (c == -1)
587                                 goto endcase;
588                         if (c == ' ' || c == '\t') {
589                                 clist_putc(c, &tp->t_rawq);
590                                 goto endcase;
591                         }
592                         ctype = ISALPHA(c);
593                         /*
594                          * erase rest of word
595                          */
596                         do {
597                                 ttyrub(c, tp);
598                                 c = clist_unputc(&tp->t_rawq);
599                                 if (c == -1)
600                                         goto endcase;
601                         } while (c != ' ' && c != '\t' &&
602                             (!ISSET(lflag, ALTWERASE) || ISALPHA(c) == ctype));
603                         clist_putc(c, &tp->t_rawq);
604                         goto endcase;
605                 }
606                 /*
607                  * reprint line (^R)
608                  */
609                 if (CCEQ(cc[VREPRINT], c) && ISSET(lflag, IEXTEN)) {
610                         ttyretype(tp);
611                         goto endcase;
612                 }
613                 /*
614                  * ^T - kernel info and generate SIGINFO
615                  */
616                 if (CCEQ(cc[VSTATUS], c) && ISSET(lflag, IEXTEN)) {
617                         if (ISSET(lflag, ISIG))
618                                 pgsignal(tp->t_pgrp, SIGINFO, 1);
619                         if (!ISSET(lflag, NOKERNINFO))
620                                 ttyinfo(tp);
621                         goto endcase;
622                 }
623                 if (CCEQ(cc[VCHECKPT], c) && ISSET(lflag, IEXTEN)) {
624                         if (ISSET(lflag, ISIG))
625                                 pgsignal(tp->t_pgrp, SIGCKPT, 1);
626                         goto endcase;
627                 }
628         }
629         /*
630          * Check for input buffer overflow
631          */
632         if (tp->t_rawq.c_cc + tp->t_canq.c_cc >= MAX_INPUT) {
633 input_overflow:
634                 if (ISSET(iflag, IMAXBEL)) {
635                         if (tp->t_outq.c_cc < tp->t_ohiwat)
636                                 (void)ttyoutput(CTRL('g'), tp);
637                 }
638                 goto endcase;
639         }
640
641         if (   c == 0377 && ISSET(iflag, PARMRK) && !ISSET(iflag, ISTRIP)
642              && ISSET(iflag, IGNBRK|IGNPAR) != (IGNBRK|IGNPAR))
643                 clist_putc(0377 | TTY_QUOTE, &tp->t_rawq);
644
645         /*
646          * Put data char in q for user and
647          * wakeup on seeing a line delimiter.
648          */
649         if (clist_putc(c, &tp->t_rawq) >= 0) {
650                 if (!ISSET(lflag, ICANON)) {
651                         ttwakeup(tp);
652                         ttyecho(c, tp);
653                         goto endcase;
654                 }
655                 if (TTBREAKC(c, lflag)) {
656                         tp->t_rocount = 0;
657                         catq(&tp->t_rawq, &tp->t_canq);
658                         ttwakeup(tp);
659                 } else if (tp->t_rocount++ == 0)
660                         tp->t_rocol = tp->t_column;
661                 if (ISSET(tp->t_state, TS_ERASE)) {
662                         /*
663                          * end of prterase \.../
664                          */
665                         CLR(tp->t_state, TS_ERASE);
666                         (void)ttyoutput('/', tp);
667                 }
668                 i = tp->t_column;
669                 ttyecho(c, tp);
670                 if (CCEQ(cc[VEOF], c) && ISSET(lflag, ECHO)) {
671                         /*
672                          * Place the cursor over the '^' of the ^D.
673                          */
674                         i = imin(2, tp->t_column - i);
675                         while (i > 0) {
676                                 (void)ttyoutput('\b', tp);
677                                 i--;
678                         }
679                 }
680         }
681 endcase:
682         /*
683          * IXANY means allow any character to restart output.
684          */
685         if (ISSET(tp->t_state, TS_TTSTOP) &&
686             !ISSET(iflag, IXANY) && cc[VSTART] != cc[VSTOP])
687                 return (0);
688 restartoutput:
689         CLR(tp->t_lflag, FLUSHO);
690         CLR(tp->t_state, TS_TTSTOP);
691 startoutput:
692         return (ttstart(tp));
693 }
694
695 /*
696  * Output a single character on a tty, doing output processing
697  * as needed (expanding tabs, newline processing, etc.).
698  * Returns < 0 if succeeds, otherwise returns char to resend.
699  * Must be recursive.
700  */
701 static int
702 ttyoutput(int c, struct tty *tp)
703 {
704         tcflag_t oflag;
705         int col;
706
707         oflag = tp->t_oflag;
708         if (!ISSET(oflag, OPOST)) {
709                 if (ISSET(tp->t_lflag, FLUSHO))
710                         return (-1);
711                 if (clist_putc(c, &tp->t_outq))
712                         return (c);
713                 tk_nout++;
714                 tp->t_outcc++;
715                 return (-1);
716         }
717         /*
718          * Do tab expansion if OXTABS is set.  Special case if we external
719          * processing, we don't do the tab expansion because we'll probably
720          * get it wrong.  If tab expansion needs to be done, let it happen
721          * externally.
722          */
723         CLR(c, ~TTY_CHARMASK);
724         if (c == '\t' &&
725             ISSET(oflag, OXTABS) && !ISSET(tp->t_lflag, EXTPROC)) {
726                 c = 8 - (tp->t_column & 7);
727                 if (!ISSET(tp->t_lflag, FLUSHO)) {
728                         crit_enter();           /* Don't interrupt tabs. */
729                         c -= b_to_q("        ", c, &tp->t_outq);
730                         tk_nout += c;
731                         tp->t_outcc += c;
732                         crit_exit();
733                 }
734                 tp->t_column += c;
735                 return (c ? -1 : '\t');
736         }
737         if (c == CEOT && ISSET(oflag, ONOEOT))
738                 return (-1);
739
740         /*
741          * Newline translation: if ONLCR is set,
742          * translate newline into "\r\n".
743          */
744         if (c == '\n' && ISSET(tp->t_oflag, ONLCR)) {
745                 tk_nout++;
746                 tp->t_outcc++;
747                 if (!ISSET(tp->t_lflag, FLUSHO) && clist_putc('\r', &tp->t_outq))
748                         return (c);
749         }
750         /* If OCRNL is set, translate "\r" into "\n". */
751         else if (c == '\r' && ISSET(tp->t_oflag, OCRNL))
752                 c = '\n';
753         /* If ONOCR is set, don't transmit CRs when on column 0. */
754         else if (c == '\r' && ISSET(tp->t_oflag, ONOCR) && tp->t_column == 0)
755                 return (-1);
756
757         tk_nout++;
758         tp->t_outcc++;
759         if (!ISSET(tp->t_lflag, FLUSHO) && clist_putc(c, &tp->t_outq))
760                 return (c);
761
762         col = tp->t_column;
763         switch (CCLASS(c)) {
764         case BACKSPACE:
765                 if (col > 0)
766                         --col;
767                 break;
768         case CONTROL:
769                 break;
770         case NEWLINE:
771                 if (ISSET(tp->t_oflag, ONLCR | ONLRET))
772                         col = 0;
773                 break;
774         case RETURN:
775                 col = 0;
776                 break;
777         case ORDINARY:
778                 ++col;
779                 break;
780         case TAB:
781                 col = (col + 8) & ~7;
782                 break;
783         }
784         tp->t_column = col;
785         return (-1);
786 }
787
788 /*
789  * Ioctls for all tty devices.  Called after line-discipline specific ioctl
790  * has been called to do discipline-specific functions and/or reject any
791  * of these ioctl commands.
792  */
793 /* ARGSUSED */
794 int
795 ttioctl(struct tty *tp, u_long cmd, void *data, int flag)
796 {
797         struct thread *td = curthread;
798         struct lwp *lp = td->td_lwp;
799         struct proc *p = td->td_proc;
800         int error;
801
802         KKASSERT(p);
803
804         /* If the ioctl involves modification, hang if in the background. */
805         switch (cmd) {
806         case  TIOCCBRK:
807         case  TIOCCONS:
808         case  TIOCDRAIN:
809         case  TIOCEXCL:
810         case  TIOCFLUSH:
811 #ifdef TIOCHPCL
812         case  TIOCHPCL:
813 #endif
814         case  TIOCNXCL:
815         case  TIOCSBRK:
816         case  TIOCSCTTY:
817         case  TIOCSDRAINWAIT:
818         case  TIOCSETA:
819         case  TIOCSETAF:
820         case  TIOCSETAW:
821         case  TIOCSETD:
822         case  TIOCSPGRP:
823         case  TIOCSTART:
824         case  TIOCSTAT:
825         case  TIOCSTI:
826         case  TIOCSTOP:
827         case  TIOCSWINSZ:
828 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
829         case  TIOCLBIC:
830         case  TIOCLBIS:
831         case  TIOCLSET:
832         case  TIOCSETC:
833         case OTIOCSETD:
834         case  TIOCSETN:
835         case  TIOCSETP:
836         case  TIOCSLTC:
837 #endif
838                 while (isbackground(p, tp) && !(p->p_flag & P_PPWAIT) &&
839                     !SIGISMEMBER(p->p_sigignore, SIGTTOU) &&
840                     !SIGISMEMBER(lp->lwp_sigmask, SIGTTOU)) {
841                         if (p->p_pgrp->pg_jobc == 0)
842                                 return (EIO);
843                         pgsignal(p->p_pgrp, SIGTTOU, 1);
844                         error = ttysleep(tp, &lbolt, PCATCH, "ttybg1",
845                                          0);
846                         if (error)
847                                 return (error);
848                 }
849                 break;
850         }
851
852         switch (cmd) {                  /* Process the ioctl. */
853         case FIOASYNC:                  /* set/clear async i/o */
854                 crit_enter();
855                 if (*(int *)data)
856                         SET(tp->t_state, TS_ASYNC);
857                 else
858                         CLR(tp->t_state, TS_ASYNC);
859                 crit_exit();
860                 break;
861         case FIONREAD:                  /* get # bytes to read */
862                 crit_enter();
863                 *(int *)data = ttnread(tp);
864                 crit_exit();
865                 break;
866
867         case FIOSETOWN:
868                 /*
869                  * Policy -- Don't allow FIOSETOWN on someone else's 
870                  *           controlling tty
871                  */
872                 if (tp->t_session != NULL && !isctty(p, tp))
873                         return (ENOTTY);
874
875                 error = fsetown(*(int *)data, &tp->t_sigio);
876                 if (error)
877                         return (error);
878                 break;
879         case FIOGETOWN:
880                 if (tp->t_session != NULL && !isctty(p, tp))
881                         return (ENOTTY);
882                 *(int *)data = fgetown(tp->t_sigio);
883                 break;
884
885         case TIOCEXCL:                  /* set exclusive use of tty */
886                 crit_enter();
887                 SET(tp->t_state, TS_XCLUDE);
888                 crit_exit();
889                 break;
890         case TIOCFLUSH: {               /* flush buffers */
891                 int flags = *(int *)data;
892
893                 if (flags == 0)
894                         flags = FREAD | FWRITE;
895                 else
896                         flags &= FREAD | FWRITE;
897                 ttyflush(tp, flags);
898                 break;
899         }
900         case TIOCCONS:                  /* become virtual console */
901                 if (*(int *)data) {
902                         if (constty && constty != tp &&
903                             ISSET(constty->t_state, TS_CONNECTED))
904                                 return (EBUSY);
905 #ifndef UCONSOLE
906                         if ((error = priv_check(td, PRIV_ROOT)) != 0)
907                                 return (error);
908 #endif
909                         constty = tp;
910                 } else if (tp == constty)
911                         constty = NULL;
912                 break;
913         case TIOCDRAIN:                 /* wait till output drained */
914                 error = ttywait(tp);
915                 if (error)
916                         return (error);
917                 break;
918         case TIOCGETA: {                /* get termios struct */
919                 struct termios *t = (struct termios *)data;
920
921                 bcopy(&tp->t_termios, t, sizeof(struct termios));
922                 break;
923         }
924         case TIOCGETD:                  /* get line discipline */
925                 *(int *)data = tp->t_line;
926                 break;
927         case TIOCGWINSZ:                /* get window size */
928                 *(struct winsize *)data = tp->t_winsize;
929                 break;
930         case TIOCGPGRP:                 /* get pgrp of tty */
931                 if (!isctty(p, tp))
932                         return (ENOTTY);
933                 *(int *)data = tp->t_pgrp ? tp->t_pgrp->pg_id : NO_PID;
934                 break;
935         case TIOCGSID:                  /* get sid of tty */
936                 if (!isctty(p, tp))
937                         return (ENOTTY);
938                 *(int *)data = tp->t_session->s_sid;
939                 break;
940 #ifdef TIOCHPCL
941         case TIOCHPCL:                  /* hang up on last close */
942                 crit_enter();
943                 SET(tp->t_cflag, HUPCL);
944                 crit_exit();
945                 break;
946 #endif
947         case TIOCNXCL:                  /* reset exclusive use of tty */
948                 crit_enter();
949                 CLR(tp->t_state, TS_XCLUDE);
950                 crit_exit();
951                 break;
952         case TIOCOUTQ:                  /* output queue size */
953                 *(int *)data = tp->t_outq.c_cc;
954                 break;
955         case TIOCSETA:                  /* set termios struct */
956         case TIOCSETAW:                 /* drain output, set */
957         case TIOCSETAF: {               /* drn out, fls in, set */
958                 struct termios *t = (struct termios *)data;
959
960                 if (t->c_ispeed == 0)
961                         t->c_ispeed = t->c_ospeed;
962                 if (t->c_ispeed == 0)
963                         t->c_ispeed = tp->t_ospeed;
964                 if (t->c_ispeed == 0)
965                         return (EINVAL);
966                 crit_enter();
967                 if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
968                         error = ttywait(tp);
969                         if (error) {
970                                 crit_exit();
971                                 return (error);
972                         }
973                         if (cmd == TIOCSETAF)
974                                 ttyflush(tp, FREAD);
975                 }
976                 if (!ISSET(t->c_cflag, CIGNORE)) {
977                         /*
978                          * Set device hardware.
979                          */
980                         if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
981                                 crit_exit();
982                                 return (error);
983                         }
984                         if (ISSET(t->c_cflag, CLOCAL) &&
985                             !ISSET(tp->t_cflag, CLOCAL)) {
986                                 /*
987                                  * XXX disconnections would be too hard to
988                                  * get rid of without this kludge.  The only
989                                  * way to get rid of controlling terminals
990                                  * is to exit from the session leader.
991                                  */
992                                 CLR(tp->t_state, TS_ZOMBIE);
993
994                                 wakeup(TSA_CARR_ON(tp));
995                                 ttwakeup(tp);
996                                 ttwwakeup(tp);
997                         }
998                         if ((ISSET(tp->t_state, TS_CARR_ON) ||
999                              ISSET(t->c_cflag, CLOCAL)) &&
1000                             !ISSET(tp->t_state, TS_ZOMBIE))
1001                                 SET(tp->t_state, TS_CONNECTED);
1002                         else
1003                                 CLR(tp->t_state, TS_CONNECTED);
1004                         tp->t_cflag = t->c_cflag;
1005                         tp->t_ispeed = t->c_ispeed;
1006                         if (t->c_ospeed != 0)
1007                                 tp->t_ospeed = t->c_ospeed;
1008                         ttsetwater(tp);
1009                 }
1010                 if (ISSET(t->c_lflag, ICANON) != ISSET(tp->t_lflag, ICANON) &&
1011                     cmd != TIOCSETAF) {
1012                         if (ISSET(t->c_lflag, ICANON))
1013                                 SET(tp->t_lflag, PENDIN);
1014                         else {
1015                                 /*
1016                                  * XXX we really shouldn't allow toggling
1017                                  * ICANON while we're in a non-termios line
1018                                  * discipline.  Now we have to worry about
1019                                  * panicing for a null queue.
1020                                  */
1021                                 if (tp->t_canq.c_cbreserved > 0 &&
1022                                     tp->t_rawq.c_cbreserved > 0) {
1023                                         catq(&tp->t_rawq, &tp->t_canq);
1024                                         /*
1025                                          * XXX the queue limits may be
1026                                          * different, so the old queue
1027                                          * swapping method no longer works.
1028                                          */
1029                                         catq(&tp->t_canq, &tp->t_rawq);
1030                                 }
1031                                 CLR(tp->t_lflag, PENDIN);
1032                         }
1033                         ttwakeup(tp);
1034                 }
1035                 tp->t_iflag = t->c_iflag;
1036                 tp->t_oflag = t->c_oflag;
1037                 /*
1038                  * Make the EXTPROC bit read only.
1039                  */
1040                 if (ISSET(tp->t_lflag, EXTPROC))
1041                         SET(t->c_lflag, EXTPROC);
1042                 else
1043                         CLR(t->c_lflag, EXTPROC);
1044                 tp->t_lflag = t->c_lflag | ISSET(tp->t_lflag, PENDIN);
1045                 if (t->c_cc[VMIN] != tp->t_cc[VMIN] ||
1046                     t->c_cc[VTIME] != tp->t_cc[VTIME])
1047                         ttwakeup(tp);
1048                 bcopy(t->c_cc, tp->t_cc, sizeof(t->c_cc));
1049                 crit_exit();
1050                 break;
1051         }
1052         case TIOCSETD: {                /* set line discipline */
1053                 int t = *(int *)data;
1054                 cdev_t device = tp->t_dev;
1055
1056                 if ((u_int)t >= nlinesw)
1057                         return (ENXIO);
1058                 if (t != tp->t_line) {
1059                         crit_enter();
1060                         (*linesw[tp->t_line].l_close)(tp, flag);
1061                         error = (*linesw[t].l_open)(device, tp);
1062                         if (error) {
1063                                 (void)(*linesw[tp->t_line].l_open)(device, tp);
1064                                 crit_exit();
1065                                 return (error);
1066                         }
1067                         tp->t_line = t;
1068                         crit_exit();
1069                 }
1070                 break;
1071         }
1072         case TIOCSTART:                 /* start output, like ^Q */
1073                 crit_enter();
1074                 if (ISSET(tp->t_state, TS_TTSTOP) ||
1075                     ISSET(tp->t_lflag, FLUSHO)) {
1076                         CLR(tp->t_lflag, FLUSHO);
1077                         CLR(tp->t_state, TS_TTSTOP);
1078                         ttstart(tp);
1079                 }
1080                 crit_exit();
1081                 break;
1082         case TIOCSTI:                   /* simulate terminal input */
1083                 if ((flag & FREAD) == 0 && priv_check(td, PRIV_ROOT))
1084                         return (EPERM);
1085                 if (!isctty(p, tp) && priv_check(td, PRIV_ROOT))
1086                         return (EACCES);
1087                 crit_enter();
1088                 (*linesw[tp->t_line].l_rint)(*(u_char *)data, tp);
1089                 crit_exit();
1090                 break;
1091         case TIOCSTOP:                  /* stop output, like ^S */
1092                 crit_enter();
1093                 if (!ISSET(tp->t_state, TS_TTSTOP)) {
1094                         SET(tp->t_state, TS_TTSTOP);
1095                         (*tp->t_stop)(tp, 0);
1096                 }
1097                 crit_exit();
1098                 break;
1099         case TIOCSCTTY:                 /* become controlling tty */
1100                 /* Session ctty vnode pointer set in vnode layer. */
1101                 if (!SESS_LEADER(p) ||
1102                     ((p->p_session->s_ttyvp || tp->t_session) &&
1103                     (tp->t_session != p->p_session)))
1104                         return (EPERM);
1105                 tp->t_session = p->p_session;
1106                 tp->t_pgrp = p->p_pgrp;
1107                 p->p_session->s_ttyp = tp;
1108                 p->p_flag |= P_CONTROLT;
1109                 break;
1110         case TIOCSPGRP: {               /* set pgrp of tty */
1111                 pid_t pgid = *(int *)data;
1112
1113                 if (!isctty(p, tp))
1114                         return (ENOTTY);
1115                 else if (pgid < 1 || pgid > PID_MAX)
1116                         return (EINVAL);
1117                 else {
1118                         struct pgrp *pgrp = pgfind(pgid);
1119                         if (pgrp == NULL || pgrp->pg_session != p->p_session)
1120                                 return (EPERM);
1121
1122                         tp->t_pgrp = pgrp;
1123                 }
1124                 break;
1125         }
1126         case TIOCSTAT:                  /* simulate control-T */
1127                 crit_enter();
1128                 ttyinfo(tp);
1129                 crit_exit();
1130                 break;
1131         case TIOCSWINSZ:                /* set window size */
1132                 if (bcmp((caddr_t)&tp->t_winsize, data,
1133                     sizeof (struct winsize))) {
1134                         tp->t_winsize = *(struct winsize *)data;
1135                         pgsignal(tp->t_pgrp, SIGWINCH, 1);
1136                 }
1137                 break;
1138         case TIOCSDRAINWAIT:
1139                 error = priv_check(td, PRIV_ROOT);
1140                 if (error)
1141                         return (error);
1142                 tp->t_timeout = *(int *)data * hz;
1143                 wakeup(TSA_OCOMPLETE(tp));
1144                 wakeup(TSA_OLOWAT(tp));
1145                 break;
1146         case TIOCGDRAINWAIT:
1147                 *(int *)data = tp->t_timeout / hz;
1148                 break;
1149         default:
1150 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
1151                 return (ttcompat(tp, cmd, data, flag));
1152 #else
1153                 return (ENOIOCTL);
1154 #endif
1155         }
1156         return (0);
1157 }
1158
1159 static struct filterops ttyread_filtops =
1160         { FILTEROP_ISFD, NULL, filt_ttyrdetach, filt_ttyread };
1161 static struct filterops ttywrite_filtops =
1162         { FILTEROP_ISFD, NULL, filt_ttywdetach, filt_ttywrite };
1163
1164 int
1165 ttykqfilter(struct dev_kqfilter_args *ap)
1166 {
1167         cdev_t dev = ap->a_head.a_dev;
1168         struct knote *kn = ap->a_kn;
1169         struct tty *tp = dev->si_tty;
1170         struct klist *klist;
1171
1172         ap->a_result = 0;
1173         switch (kn->kn_filter) {
1174         case EVFILT_READ:
1175                 klist = &tp->t_rkq.ki_note;
1176                 kn->kn_fop = &ttyread_filtops;
1177                 break;
1178         case EVFILT_WRITE:
1179                 klist = &tp->t_wkq.ki_note;
1180                 kn->kn_fop = &ttywrite_filtops;
1181                 break;
1182         default:
1183                 ap->a_result = EOPNOTSUPP;
1184                 return (0);
1185         }
1186
1187         kn->kn_hook = (caddr_t)dev;
1188         knote_insert(klist, kn);
1189
1190         return (0);
1191 }
1192
1193 static void
1194 filt_ttyrdetach(struct knote *kn)
1195 {
1196         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1197
1198         knote_remove(&tp->t_rkq.ki_note, kn);
1199 }
1200
1201 static int
1202 filt_ttyread(struct knote *kn, long hint)
1203 {
1204         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1205
1206         kn->kn_data = ttnread(tp);
1207         if (ISSET(tp->t_state, TS_ZOMBIE)) {
1208                 kn->kn_flags |= EV_EOF;
1209                 return (1);
1210         }
1211         return (kn->kn_data > 0);
1212 }
1213
1214 static void
1215 filt_ttywdetach(struct knote *kn)
1216 {
1217         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1218
1219         knote_remove(&tp->t_wkq.ki_note, kn);
1220 }
1221
1222 static int
1223 filt_ttywrite(struct knote *kn, long hint)
1224 {
1225         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1226
1227         kn->kn_data = tp->t_outq.c_cc;
1228         if (ISSET(tp->t_state, TS_ZOMBIE))
1229                 return (1);
1230         return (kn->kn_data <= tp->t_olowat &&
1231             ISSET(tp->t_state, TS_CONNECTED));
1232 }
1233
1234 /*
1235  * Must be called while in a critical section.
1236  */
1237 static int
1238 ttnread(struct tty *tp)
1239 {
1240         int nread;
1241
1242         if (ISSET(tp->t_lflag, PENDIN))
1243                 ttypend(tp);
1244         nread = tp->t_canq.c_cc;
1245         if (!ISSET(tp->t_lflag, ICANON)) {
1246                 nread += tp->t_rawq.c_cc;
1247                 if (nread < tp->t_cc[VMIN] && tp->t_cc[VTIME] == 0)
1248                         nread = 0;
1249         }
1250         return (nread);
1251 }
1252
1253 /*
1254  * Wait for output to drain.
1255  */
1256 int
1257 ttywait(struct tty *tp)
1258 {
1259         int error;
1260
1261         error = 0;
1262         crit_enter();
1263         while ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1264                ISSET(tp->t_state, TS_CONNECTED) && tp->t_oproc) {
1265                 (*tp->t_oproc)(tp);
1266                 if ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1267                     ISSET(tp->t_state, TS_CONNECTED)) {
1268                         SET(tp->t_state, TS_SO_OCOMPLETE);
1269                         error = ttysleep(tp, TSA_OCOMPLETE(tp),
1270                                          PCATCH, "ttywai",
1271                                          tp->t_timeout);
1272                         if (error) {
1273                                 if (error == EWOULDBLOCK)
1274                                         error = EIO;
1275                                 break;
1276                         }
1277                 } else
1278                         break;
1279         }
1280         if (!error && (tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)))
1281                 error = EIO;
1282         crit_exit();
1283         return (error);
1284 }
1285
1286 /*
1287  * Flush if successfully wait.
1288  */
1289 static int
1290 ttywflush(struct tty *tp)
1291 {
1292         int error;
1293
1294         if ((error = ttywait(tp)) == 0)
1295                 ttyflush(tp, FREAD);
1296         return (error);
1297 }
1298
1299 /*
1300  * Flush tty read and/or write queues, notifying anyone waiting.
1301  */
1302 void
1303 ttyflush(struct tty *tp, int rw)
1304 {
1305         crit_enter();
1306 #if 0
1307 again:
1308 #endif
1309         if (rw & FWRITE) {
1310                 FLUSHQ(&tp->t_outq);
1311                 CLR(tp->t_state, TS_TTSTOP);
1312         }
1313         (*tp->t_stop)(tp, rw);
1314         if (rw & FREAD) {
1315                 FLUSHQ(&tp->t_canq);
1316                 FLUSHQ(&tp->t_rawq);
1317                 CLR(tp->t_lflag, PENDIN);
1318                 tp->t_rocount = 0;
1319                 tp->t_rocol = 0;
1320                 CLR(tp->t_state, TS_LOCAL);
1321                 ttwakeup(tp);
1322                 if (ISSET(tp->t_state, TS_TBLOCK)) {
1323                         if (rw & FWRITE)
1324                                 FLUSHQ(&tp->t_outq);
1325                         ttyunblock(tp);
1326
1327                         /*
1328                          * Don't let leave any state that might clobber the
1329                          * next line discipline (although we should do more
1330                          * to send the START char).  Not clearing the state
1331                          * may have caused the "putc to a clist with no
1332                          * reserved cblocks" panic/kprintf.
1333                          */
1334                         CLR(tp->t_state, TS_TBLOCK);
1335
1336 #if 0 /* forget it, sleeping isn't always safe and we don't know when it is */
1337                         if (ISSET(tp->t_iflag, IXOFF)) {
1338                                 /*
1339                                  * XXX wait a bit in the hope that the stop
1340                                  * character (if any) will go out.  Waiting
1341                                  * isn't good since it allows races.  This
1342                                  * will be fixed when the stop character is
1343                                  * put in a special queue.  Don't bother with
1344                                  * the checks in ttywait() since the timeout
1345                                  * will save us.
1346                                  */
1347                                 SET(tp->t_state, TS_SO_OCOMPLETE);
1348                                 ttysleep(tp, TSA_OCOMPLETE(tp), 0,
1349                                          "ttyfls", hz / 10);
1350                                 /*
1351                                  * Don't try sending the stop character again.
1352                                  */
1353                                 CLR(tp->t_state, TS_TBLOCK);
1354                                 goto again;
1355                         }
1356 #endif
1357                 }
1358         }
1359         if (rw & FWRITE) {
1360                 FLUSHQ(&tp->t_outq);
1361                 ttwwakeup(tp);
1362         }
1363         crit_exit();
1364 }
1365
1366 /*
1367  * Copy in the default termios characters.
1368  */
1369 void
1370 termioschars(struct termios *t)
1371 {
1372
1373         bcopy(ttydefchars, t->c_cc, sizeof t->c_cc);
1374 }
1375
1376 /*
1377  * Old interface.
1378  */
1379 void
1380 ttychars(struct tty *tp)
1381 {
1382
1383         termioschars(&tp->t_termios);
1384 }
1385
1386 /*
1387  * Handle input high water.  Send stop character for the IXOFF case.  Turn
1388  * on our input flow control bit and propagate the changes to the driver.
1389  * XXX the stop character should be put in a special high priority queue.
1390  */
1391 void
1392 ttyblock(struct tty *tp)
1393 {
1394
1395         SET(tp->t_state, TS_TBLOCK);
1396         if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTOP] != _POSIX_VDISABLE &&
1397             clist_putc(tp->t_cc[VSTOP], &tp->t_outq) != 0)
1398                 CLR(tp->t_state, TS_TBLOCK);    /* try again later */
1399         ttstart(tp);
1400 }
1401
1402 /*
1403  * Handle input low water.  Send start character for the IXOFF case.  Turn
1404  * off our input flow control bit and propagate the changes to the driver.
1405  * XXX the start character should be put in a special high priority queue.
1406  */
1407 static void
1408 ttyunblock(struct tty *tp)
1409 {
1410
1411         CLR(tp->t_state, TS_TBLOCK);
1412         if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTART] != _POSIX_VDISABLE &&
1413             clist_putc(tp->t_cc[VSTART], &tp->t_outq) != 0)
1414                 SET(tp->t_state, TS_TBLOCK);    /* try again later */
1415         ttstart(tp);
1416 }
1417
1418 #ifdef notyet
1419 /* Not used by any current (i386) drivers. */
1420 /*
1421  * Restart after an inter-char delay.
1422  */
1423 void
1424 ttrstrt(void *tp_arg)
1425 {
1426         struct tty *tp;
1427
1428         KASSERT(tp_arg != NULL, ("ttrstrt"));
1429
1430         tp = tp_arg;
1431         crit_enter();
1432         CLR(tp->t_state, TS_TIMEOUT);
1433         ttstart(tp);
1434         crit_exit();
1435 }
1436 #endif
1437
1438 int
1439 ttstart(struct tty *tp)
1440 {
1441
1442         if (tp->t_oproc != NULL)        /* XXX: Kludge for pty. */
1443                 (*tp->t_oproc)(tp);
1444         return (0);
1445 }
1446
1447 /*
1448  * "close" a line discipline
1449  */
1450 int
1451 ttylclose(struct tty *tp, int flag)
1452 {
1453
1454         if (flag & FNONBLOCK || ttywflush(tp))
1455                 ttyflush(tp, FREAD | FWRITE);
1456         return (0);
1457 }
1458
1459 /*
1460  * Handle modem control transition on a tty.
1461  * Flag indicates new state of carrier.
1462  * Returns 0 if the line should be turned off, otherwise 1.
1463  */
1464 int
1465 ttymodem(struct tty *tp, int flag)
1466 {
1467
1468         if (ISSET(tp->t_state, TS_CARR_ON) && ISSET(tp->t_cflag, MDMBUF)) {
1469                 /*
1470                  * MDMBUF: do flow control according to carrier flag
1471                  * XXX TS_CAR_OFLOW doesn't do anything yet.  TS_TTSTOP
1472                  * works if IXON and IXANY are clear.
1473                  */
1474                 if (flag) {
1475                         CLR(tp->t_state, TS_CAR_OFLOW);
1476                         CLR(tp->t_state, TS_TTSTOP);
1477                         ttstart(tp);
1478                 } else if (!ISSET(tp->t_state, TS_CAR_OFLOW)) {
1479                         SET(tp->t_state, TS_CAR_OFLOW);
1480                         SET(tp->t_state, TS_TTSTOP);
1481                         (*tp->t_stop)(tp, 0);
1482                 }
1483         } else if (flag == 0) {
1484                 /*
1485                  * Lost carrier.
1486                  */
1487                 CLR(tp->t_state, TS_CARR_ON);
1488                 if (ISSET(tp->t_state, TS_ISOPEN) &&
1489                     !ISSET(tp->t_cflag, CLOCAL)) {
1490                         SET(tp->t_state, TS_ZOMBIE);
1491                         CLR(tp->t_state, TS_CONNECTED);
1492                         if (tp->t_session && tp->t_session->s_leader)
1493                                 ksignal(tp->t_session->s_leader, SIGHUP);
1494                         ttyflush(tp, FREAD | FWRITE);
1495                         return (0);
1496                 }
1497         } else {
1498                 /*
1499                  * Carrier now on.
1500                  */
1501                 SET(tp->t_state, TS_CARR_ON);
1502                 if (!ISSET(tp->t_state, TS_ZOMBIE))
1503                         SET(tp->t_state, TS_CONNECTED);
1504                 wakeup(TSA_CARR_ON(tp));
1505                 ttwakeup(tp);
1506                 ttwwakeup(tp);
1507         }
1508         return (1);
1509 }
1510
1511 /*
1512  * Reinput pending characters after state switch
1513  * call from a critical section.
1514  */
1515 static void
1516 ttypend(struct tty *tp)
1517 {
1518         struct clist tq;
1519         int c;
1520
1521         CLR(tp->t_lflag, PENDIN);
1522         SET(tp->t_state, TS_TYPEN);
1523         /*
1524          * XXX this assumes too much about clist internals.  It may even
1525          * fail if the cblock slush pool is empty.  We can't allocate more
1526          * cblocks here because we are called from an interrupt handler
1527          * and clist_alloc_cblocks() can wait.
1528          */
1529         tq = tp->t_rawq;
1530         bzero(&tp->t_rawq, sizeof tp->t_rawq);
1531         tp->t_rawq.c_cbmax = tq.c_cbmax;
1532         tp->t_rawq.c_cbreserved = tq.c_cbreserved;
1533         while ((c = clist_getc(&tq)) >= 0)
1534                 ttyinput(c, tp);
1535         CLR(tp->t_state, TS_TYPEN);
1536 }
1537
1538 /*
1539  * Process a read call on a tty device.
1540  */
1541 int
1542 ttread(struct tty *tp, struct uio *uio, int flag)
1543 {
1544         struct clist *qp;
1545         int c;
1546         tcflag_t lflag;
1547         cc_t *cc = tp->t_cc;
1548         struct proc *pp;
1549         struct lwp *lp;
1550         int first, error = 0;
1551         int has_stime = 0, last_cc = 0;
1552         long slp = 0;           /* XXX this should be renamed `timo'. */
1553         struct timeval stime;
1554
1555         lp = curthread->td_lwp;
1556         stime.tv_sec = 0;       /* fix compiler warnings */
1557         stime.tv_usec = 0;
1558
1559 loop:
1560         crit_enter();
1561         lflag = tp->t_lflag;
1562         /*
1563          * take pending input first
1564          */
1565         if (ISSET(lflag, PENDIN)) {
1566                 ttypend(tp);
1567                 splz();         /* reduce latency */
1568                 lflag = tp->t_lflag;    /* XXX ttypend() clobbers it */
1569         }
1570
1571         /*
1572          * Hang process if it's in the background.
1573          */
1574         if ((pp = curproc) && isbackground(pp, tp)) {
1575                 crit_exit();
1576                 if (SIGISMEMBER(pp->p_sigignore, SIGTTIN) ||
1577                     SIGISMEMBER(lp->lwp_sigmask, SIGTTIN) ||
1578                     (pp->p_flag & P_PPWAIT) || pp->p_pgrp->pg_jobc == 0)
1579                         return (EIO);
1580                 pgsignal(pp->p_pgrp, SIGTTIN, 1);
1581                 error = ttysleep(tp, &lbolt, PCATCH, "ttybg2", 0);
1582                 if (error)
1583                         return (error);
1584                 goto loop;
1585         }
1586
1587         if (ISSET(tp->t_state, TS_ZOMBIE)) {
1588                 crit_exit();
1589                 return (0);     /* EOF */
1590         }
1591
1592         /*
1593          * If canonical, use the canonical queue,
1594          * else use the raw queue.
1595          *
1596          * (should get rid of clists...)
1597          */
1598         qp = ISSET(lflag, ICANON) ? &tp->t_canq : &tp->t_rawq;
1599
1600         if (flag & IO_NDELAY) {
1601                 if (qp->c_cc > 0)
1602                         goto read;
1603                 if (!ISSET(lflag, ICANON) && cc[VMIN] == 0) {
1604                         crit_exit();
1605                         return (0);
1606                 }
1607                 crit_exit();
1608                 return (EWOULDBLOCK);
1609         }
1610         if (!ISSET(lflag, ICANON)) {
1611                 int m = cc[VMIN];
1612                 long t = cc[VTIME];
1613                 struct timeval timecopy;
1614
1615                 /*
1616                  * Check each of the four combinations.
1617                  * (m > 0 && t == 0) is the normal read case.
1618                  * It should be fairly efficient, so we check that and its
1619                  * companion case (m == 0 && t == 0) first.
1620                  * For the other two cases, we compute the target sleep time
1621                  * into slp.
1622                  */
1623                 if (t == 0) {
1624                         if (qp->c_cc < m)
1625                                 goto sleep;
1626                         if (qp->c_cc > 0)
1627                                 goto read;
1628
1629                         /* m, t and qp->c_cc are all 0.  0 is enough input. */
1630                         crit_exit();
1631                         return (0);
1632                 }
1633                 t *= 100000;            /* time in us */
1634 #define diff(t1, t2) (((t1).tv_sec - (t2).tv_sec) * 1000000 + \
1635                          ((t1).tv_usec - (t2).tv_usec))
1636                 if (m > 0) {
1637                         if (qp->c_cc <= 0)
1638                                 goto sleep;
1639                         if (qp->c_cc >= m)
1640                                 goto read;
1641                         getmicrotime(&timecopy);
1642                         if (has_stime == 0) {
1643                                 /* first character, start timer */
1644                                 has_stime = 1;
1645                                 stime = timecopy;
1646                                 slp = t;
1647                         } else if (qp->c_cc > last_cc) {
1648                                 /* got a character, restart timer */
1649                                 stime = timecopy;
1650                                 slp = t;
1651                         } else {
1652                                 /* nothing, check expiration */
1653                                 slp = t - diff(timecopy, stime);
1654                                 if (slp <= 0)
1655                                         goto read;
1656                         }
1657                         last_cc = qp->c_cc;
1658                 } else {        /* m == 0 */
1659                         if (qp->c_cc > 0)
1660                                 goto read;
1661                         getmicrotime(&timecopy);
1662                         if (has_stime == 0) {
1663                                 has_stime = 1;
1664                                 stime = timecopy;
1665                                 slp = t;
1666                         } else {
1667                                 slp = t - diff(timecopy, stime);
1668                                 if (slp <= 0) {
1669                                         /* Timed out, but 0 is enough input. */
1670                                         crit_exit();
1671                                         return (0);
1672                                 }
1673                         }
1674                 }
1675 #undef diff
1676                 /*
1677                  * Rounding down may make us wake up just short
1678                  * of the target, so we round up.
1679                  * The formula is ceiling(slp * hz/1000000).
1680                  * 32-bit arithmetic is enough for hz < 169.
1681                  * XXX see tvtohz() for how to avoid overflow if hz
1682                  * is large (divide by `tick' and/or arrange to
1683                  * use tvtohz() if hz is large).
1684                  */
1685                 slp = (long) (((u_long)slp * hz) + 999999) / 1000000;
1686                 goto sleep;
1687         }
1688         if (qp->c_cc <= 0) {
1689 sleep:
1690                 /*
1691                  * There is no input, or not enough input and we can block.
1692                  */
1693                 error = ttysleep(tp, TSA_HUP_OR_INPUT(tp), PCATCH,
1694                                  ISSET(tp->t_state, TS_CONNECTED) ?
1695                                  "ttyin" : "ttyhup", (int)slp);
1696                 crit_exit();
1697                 if (error == EWOULDBLOCK)
1698                         error = 0;
1699                 else if (error)
1700                         return (error);
1701                 /*
1702                  * XXX what happens if another process eats some input
1703                  * while we are asleep (not just here)?  It would be
1704                  * safest to detect changes and reset our state variables
1705                  * (has_stime and last_cc).
1706                  */
1707                 slp = 0;
1708                 goto loop;
1709         }
1710 read:
1711         crit_exit();
1712         /*
1713          * Input present, check for input mapping and processing.
1714          */
1715         first = 1;
1716         if (ISSET(lflag, ICANON | ISIG))
1717                 goto slowcase;
1718         for (;;) {
1719                 char ibuf[IBUFSIZ];
1720                 int icc;
1721
1722                 icc = (int)szmin(uio->uio_resid, IBUFSIZ);
1723                 icc = q_to_b(qp, ibuf, icc);
1724                 if (icc <= 0) {
1725                         if (first)
1726                                 goto loop;
1727                         break;
1728                 }
1729                 error = uiomove(ibuf, (size_t)icc, uio);
1730                 /*
1731                  * XXX if there was an error then we should ungetc() the
1732                  * unmoved chars and reduce icc here.
1733                  */
1734                 if (error)
1735                         break;
1736                 if (uio->uio_resid == 0)
1737                         break;
1738                 first = 0;
1739         }
1740         goto out;
1741 slowcase:
1742         for (;;) {
1743                 c = clist_getc(qp);
1744                 if (c < 0) {
1745                         if (first)
1746                                 goto loop;
1747                         break;
1748                 }
1749                 /*
1750                  * delayed suspend (^Y)
1751                  */
1752                 if (CCEQ(cc[VDSUSP], c) &&
1753                     ISSET(lflag, IEXTEN | ISIG) == (IEXTEN | ISIG)) {
1754                         pgsignal(tp->t_pgrp, SIGTSTP, 1);
1755                         if (first) {
1756                                 error = ttysleep(tp, &lbolt, PCATCH,
1757                                                  "ttybg3", 0);
1758                                 if (error)
1759                                         break;
1760                                 goto loop;
1761                         }
1762                         break;
1763                 }
1764                 /*
1765                  * Interpret EOF only in canonical mode.
1766                  */
1767                 if (CCEQ(cc[VEOF], c) && ISSET(lflag, ICANON))
1768                         break;
1769                 /*
1770                  * Give user character.
1771                  */
1772                 error = ureadc(c, uio);
1773                 if (error)
1774                         /* XXX should ungetc(c, qp). */
1775                         break;
1776                 if (uio->uio_resid == 0)
1777                         break;
1778                 /*
1779                  * In canonical mode check for a "break character"
1780                  * marking the end of a "line of input".
1781                  */
1782                 if (ISSET(lflag, ICANON) && TTBREAKC(c, lflag))
1783                         break;
1784                 first = 0;
1785         }
1786
1787 out:
1788         /*
1789          * Look to unblock input now that (presumably)
1790          * the input queue has gone down.
1791          */
1792         crit_enter();
1793         if (ISSET(tp->t_state, TS_TBLOCK) &&
1794             tp->t_rawq.c_cc + tp->t_canq.c_cc <= tp->t_ilowat)
1795                 ttyunblock(tp);
1796         crit_exit();
1797
1798         return (error);
1799 }
1800
1801 /*
1802  * Check the output queue on tp for space for a kernel message (from uprintf
1803  * or tprintf).  Allow some space over the normal hiwater mark so we don't
1804  * lose messages due to normal flow control, but don't let the tty run amok.
1805  * Sleeps here are not interruptible, but we return prematurely if new signals
1806  * arrive.
1807  */
1808 int
1809 ttycheckoutq(struct tty *tp, int wait)
1810 {
1811         struct lwp *lp = curthread->td_lwp;
1812         int hiwat;
1813         sigset_t oldset, newset;
1814
1815         hiwat = tp->t_ohiwat;
1816         SIGEMPTYSET(oldset);
1817         SIGEMPTYSET(newset);
1818         crit_enter();
1819         if (wait)
1820                 oldset = lwp_sigpend(lp);
1821         if (tp->t_outq.c_cc > hiwat + OBUFSIZ + 100) {
1822                 while (tp->t_outq.c_cc > hiwat) {
1823                         ttstart(tp);
1824                         if (tp->t_outq.c_cc <= hiwat)
1825                                 break;
1826                         if (wait)
1827                                 newset = lwp_sigpend(lp);
1828                         if (!wait || SIGSETNEQ(oldset, newset)) {
1829                                 crit_exit();
1830                                 return (0);
1831                         }
1832                         SET(tp->t_state, TS_SO_OLOWAT);
1833                         tsleep(TSA_OLOWAT(tp), 0, "ttoutq", hz);
1834                 }
1835         }
1836         crit_exit();
1837         return (1);
1838 }
1839
1840 /*
1841  * Process a write call on a tty device.
1842  */
1843 int
1844 ttwrite(struct tty *tp, struct uio *uio, int flag)
1845 {
1846         char *cp = NULL;
1847         int cc, ce;
1848         struct proc *pp;
1849         struct lwp *lp;
1850         int i, hiwat, error;
1851         size_t cnt;
1852
1853         char obuf[OBUFSIZ];
1854
1855         lp = curthread->td_lwp;
1856         hiwat = tp->t_ohiwat;
1857         cnt = uio->uio_resid;
1858         error = 0;
1859         cc = 0;
1860 loop:
1861         crit_enter();
1862         if (ISSET(tp->t_state, TS_ZOMBIE)) {
1863                 crit_exit();
1864                 if (uio->uio_resid == cnt)
1865                         error = EIO;
1866                 goto out;
1867         }
1868         if (!ISSET(tp->t_state, TS_CONNECTED)) {
1869                 if (flag & IO_NDELAY) {
1870                         crit_exit();
1871                         error = EWOULDBLOCK;
1872                         goto out;
1873                 }
1874                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "ttydcd", 0);
1875                 crit_exit();
1876                 if (error)
1877                         goto out;
1878                 goto loop;
1879         }
1880         crit_exit();
1881
1882         /*
1883          * Hang the process if it's in the background.
1884          */
1885         if ((pp = curproc) && isbackground(pp, tp) &&
1886             ISSET(tp->t_lflag, TOSTOP) && !(pp->p_flag & P_PPWAIT) &&
1887             !SIGISMEMBER(pp->p_sigignore, SIGTTOU) &&
1888             !SIGISMEMBER(lp->lwp_sigmask, SIGTTOU)) {
1889                 if (pp->p_pgrp->pg_jobc == 0) {
1890                         error = EIO;
1891                         goto out;
1892                 }
1893                 pgsignal(pp->p_pgrp, SIGTTOU, 1);
1894                 error = ttysleep(tp, &lbolt, PCATCH, "ttybg4", 0);
1895                 if (error)
1896                         goto out;
1897                 goto loop;
1898         }
1899         /*
1900          * Process the user's data in at most OBUFSIZ chunks.  Perform any
1901          * output translation.  Keep track of high water mark, sleep on
1902          * overflow awaiting device aid in acquiring new space.
1903          */
1904         while (uio->uio_resid > 0 || cc > 0) {
1905                 if (ISSET(tp->t_lflag, FLUSHO)) {
1906                         uio->uio_resid = 0;
1907                         return (0);
1908                 }
1909                 if (tp->t_outq.c_cc > hiwat)
1910                         goto ovhiwat;
1911                 /*
1912                  * Grab a hunk of data from the user, unless we have some
1913                  * leftover from last time.
1914                  */
1915                 if (cc == 0) {
1916                         cc = szmin(uio->uio_resid, OBUFSIZ);
1917                         cp = obuf;
1918                         error = uiomove(cp, (size_t)cc, uio);
1919                         if (error) {
1920                                 cc = 0;
1921                                 break;
1922                         }
1923                 }
1924                 /*
1925                  * If nothing fancy need be done, grab those characters we
1926                  * can handle without any of ttyoutput's processing and
1927                  * just transfer them to the output q.  For those chars
1928                  * which require special processing (as indicated by the
1929                  * bits in char_type), call ttyoutput.  After processing
1930                  * a hunk of data, look for FLUSHO so ^O's will take effect
1931                  * immediately.
1932                  */
1933                 while (cc > 0) {
1934                         if (!ISSET(tp->t_oflag, OPOST))
1935                                 ce = cc;
1936                         else {
1937                                 ce = cc - scanc((u_int)cc, (u_char *)cp,
1938                                                 char_type, CCLASSMASK);
1939                                 /*
1940                                  * If ce is zero, then we're processing
1941                                  * a special character through ttyoutput.
1942                                  */
1943                                 if (ce == 0) {
1944                                         tp->t_rocount = 0;
1945                                         if (ttyoutput(*cp, tp) >= 0) {
1946                                                 /* No Clists, wait a bit. */
1947                                                 ttstart(tp);
1948                                                 if (flag & IO_NDELAY) {
1949                                                         error = EWOULDBLOCK;
1950                                                         goto out;
1951                                                 }
1952                                                 error = ttysleep(tp, &lbolt,
1953                                                                  PCATCH,
1954                                                                  "ttybf1", 0);
1955                                                 if (error)
1956                                                         goto out;
1957                                                 goto loop;
1958                                         }
1959                                         cp++;
1960                                         cc--;
1961                                         if (ISSET(tp->t_lflag, FLUSHO) ||
1962                                             tp->t_outq.c_cc > hiwat)
1963                                                 goto ovhiwat;
1964                                         continue;
1965                                 }
1966                         }
1967                         /*
1968                          * A bunch of normal characters have been found.
1969                          * Transfer them en masse to the output queue and
1970                          * continue processing at the top of the loop.
1971                          * If there are any further characters in this
1972                          * <= OBUFSIZ chunk, the first should be a character
1973                          * requiring special handling by ttyoutput.
1974                          */
1975                         tp->t_rocount = 0;
1976                         i = b_to_q(cp, ce, &tp->t_outq);
1977                         ce -= i;
1978                         tp->t_column += ce;
1979                         cp += ce, cc -= ce, tk_nout += ce;
1980                         tp->t_outcc += ce;
1981                         if (i > 0) {
1982                                 /* No Clists, wait a bit. */
1983                                 ttstart(tp);
1984                                 if (flag & IO_NDELAY) {
1985                                         error = EWOULDBLOCK;
1986                                         goto out;
1987                                 }
1988                                 error = ttysleep(tp, &lbolt, PCATCH,
1989                                                  "ttybf2", 0);
1990                                 if (error)
1991                                         goto out;
1992                                 goto loop;
1993                         }
1994                         if (ISSET(tp->t_lflag, FLUSHO) ||
1995                             tp->t_outq.c_cc > hiwat)
1996                                 break;
1997                 }
1998                 ttstart(tp);
1999         }
2000 out:
2001         /*
2002          * If cc is nonzero, we leave the uio structure inconsistent, as the
2003          * offset and iov pointers have moved forward, but it doesn't matter
2004          * (the call will either return short or restart with a new uio).
2005          */
2006         uio->uio_resid += cc;
2007         return (error);
2008
2009 ovhiwat:
2010         ttstart(tp);
2011         crit_enter();
2012         /*
2013          * This can only occur if FLUSHO is set in t_lflag,
2014          * or if ttstart/oproc is synchronous (or very fast).
2015          */
2016         if (tp->t_outq.c_cc <= hiwat) {
2017                 crit_exit();
2018                 goto loop;
2019         }
2020         if (flag & IO_NDELAY) {
2021                 crit_exit();
2022                 uio->uio_resid += cc;
2023                 return (uio->uio_resid == cnt ? EWOULDBLOCK : 0);
2024         }
2025         SET(tp->t_state, TS_SO_OLOWAT);
2026         error = ttysleep(tp, TSA_OLOWAT(tp), PCATCH, "ttywri", tp->t_timeout);
2027         crit_exit();
2028         if (error == EWOULDBLOCK)
2029                 error = EIO;
2030         if (error)
2031                 goto out;
2032         goto loop;
2033 }
2034
2035 /*
2036  * Rubout one character from the rawq of tp
2037  * as cleanly as possible.
2038  */
2039 static void
2040 ttyrub(int c, struct tty *tp)
2041 {
2042         char *cp;
2043         int savecol;
2044         int tabc;
2045
2046         if (!ISSET(tp->t_lflag, ECHO) || ISSET(tp->t_lflag, EXTPROC))
2047                 return;
2048         CLR(tp->t_lflag, FLUSHO);
2049         if (ISSET(tp->t_lflag, ECHOE)) {
2050                 if (tp->t_rocount == 0) {
2051                         /*
2052                          * Screwed by ttwrite; retype
2053                          */
2054                         ttyretype(tp);
2055                         return;
2056                 }
2057                 if (c == ('\t' | TTY_QUOTE) || c == ('\n' | TTY_QUOTE))
2058                         ttyrubo(tp, 2);
2059                 else {
2060                         CLR(c, ~TTY_CHARMASK);
2061                         switch (CCLASS(c)) {
2062                         case ORDINARY:
2063                                 ttyrubo(tp, 1);
2064                                 break;
2065                         case BACKSPACE:
2066                         case CONTROL:
2067                         case NEWLINE:
2068                         case RETURN:
2069                         case VTAB:
2070                                 if (ISSET(tp->t_lflag, ECHOCTL))
2071                                         ttyrubo(tp, 2);
2072                                 break;
2073                         case TAB:
2074                                 if (tp->t_rocount < tp->t_rawq.c_cc) {
2075                                         ttyretype(tp);
2076                                         return;
2077                                 }
2078                                 crit_enter();
2079                                 savecol = tp->t_column;
2080                                 SET(tp->t_state, TS_CNTTB);
2081                                 SET(tp->t_lflag, FLUSHO);
2082                                 tp->t_column = tp->t_rocol;
2083                                 cp = tp->t_rawq.c_cf;
2084                                 if (cp)
2085                                         tabc = *cp;     /* XXX FIX NEXTC */
2086                                 for (; cp; cp = nextc(&tp->t_rawq, cp, &tabc))
2087                                         ttyecho(tabc, tp);
2088                                 CLR(tp->t_lflag, FLUSHO);
2089                                 CLR(tp->t_state, TS_CNTTB);
2090                                 crit_exit();
2091
2092                                 /* savecol will now be length of the tab. */
2093                                 savecol -= tp->t_column;
2094                                 tp->t_column += savecol;
2095                                 if (savecol > 8)
2096                                         savecol = 8;    /* overflow screw */
2097                                 while (--savecol >= 0)
2098                                         (void)ttyoutput('\b', tp);
2099                                 break;
2100                         default:                        /* XXX */
2101 #define PANICSTR        "ttyrub: would panic c = %d, val = %d\n"
2102                                 (void)kprintf(PANICSTR, c, CCLASS(c));
2103 #ifdef notdef
2104                                 panic(PANICSTR, c, CCLASS(c));
2105 #endif
2106                         }
2107                 }
2108         } else if (ISSET(tp->t_lflag, ECHOPRT)) {
2109                 if (!ISSET(tp->t_state, TS_ERASE)) {
2110                         SET(tp->t_state, TS_ERASE);
2111                         (void)ttyoutput('\\', tp);
2112                 }
2113                 ttyecho(c, tp);
2114         } else {
2115                 ttyecho(tp->t_cc[VERASE], tp);
2116                 /*
2117                  * This code may be executed not only when an ERASE key
2118                  * is pressed, but also when ^U (KILL) or ^W (WERASE) are.
2119                  * So, I didn't think it was worthwhile to pass the extra
2120                  * information (which would need an extra parameter,
2121                  * changing every call) needed to distinguish the ERASE2
2122                  * case from the ERASE.
2123                  */
2124         }
2125         --tp->t_rocount;
2126 }
2127
2128 /*
2129  * Back over cnt characters, erasing them.
2130  */
2131 static void
2132 ttyrubo(struct tty *tp, int cnt)
2133 {
2134
2135         while (cnt-- > 0) {
2136                 (void)ttyoutput('\b', tp);
2137                 (void)ttyoutput(' ', tp);
2138                 (void)ttyoutput('\b', tp);
2139         }
2140 }
2141
2142 /*
2143  * ttyretype --
2144  *      Reprint the rawq line.  Note, it is assumed that c_cc has already
2145  *      been checked.
2146  */
2147 static void
2148 ttyretype(struct tty *tp)
2149 {
2150         char *cp;
2151         int c;
2152
2153         /* Echo the reprint character. */
2154         if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
2155                 ttyecho(tp->t_cc[VREPRINT], tp);
2156
2157         (void)ttyoutput('\n', tp);
2158
2159         /*
2160          * XXX
2161          * FIX: NEXTC IS BROKEN - DOESN'T CHECK QUOTE
2162          * BIT OF FIRST CHAR.
2163          */
2164         crit_enter();
2165         for (cp = tp->t_canq.c_cf, c = (cp != NULL ? *cp : 0);
2166             cp != NULL; cp = nextc(&tp->t_canq, cp, &c))
2167                 ttyecho(c, tp);
2168         for (cp = tp->t_rawq.c_cf, c = (cp != NULL ? *cp : 0);
2169             cp != NULL; cp = nextc(&tp->t_rawq, cp, &c))
2170                 ttyecho(c, tp);
2171         CLR(tp->t_state, TS_ERASE);
2172         crit_exit();
2173
2174         tp->t_rocount = tp->t_rawq.c_cc;
2175         tp->t_rocol = 0;
2176 }
2177
2178 /*
2179  * Echo a typed character to the terminal.
2180  */
2181 static void
2182 ttyecho(int c, struct tty *tp)
2183 {
2184
2185         if (!ISSET(tp->t_state, TS_CNTTB))
2186                 CLR(tp->t_lflag, FLUSHO);
2187         if ((!ISSET(tp->t_lflag, ECHO) &&
2188              (c != '\n' || !ISSET(tp->t_lflag, ECHONL))) ||
2189             ISSET(tp->t_lflag, EXTPROC))
2190                 return;
2191         if (ISSET(tp->t_lflag, ECHOCTL) &&
2192             ((ISSET(c, TTY_CHARMASK) <= 037 && c != '\t' && c != '\n') ||
2193             ISSET(c, TTY_CHARMASK) == 0177)) {
2194                 (void)ttyoutput('^', tp);
2195                 CLR(c, ~TTY_CHARMASK);
2196                 if (c == 0177)
2197                         c = '?';
2198                 else
2199                         c += 'A' - 1;
2200         }
2201         (void)ttyoutput(c, tp);
2202 }
2203
2204 /*
2205  * Wake up any readers on a tty.
2206  */
2207 void
2208 ttwakeup(struct tty *tp)
2209 {
2210
2211         if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
2212                 pgsigio(tp->t_sigio, SIGIO, (tp->t_session != NULL));
2213         wakeup(TSA_HUP_OR_INPUT(tp));
2214         KNOTE(&tp->t_rkq.ki_note, 0);
2215 }
2216
2217 /*
2218  * Wake up any writers on a tty.
2219  */
2220 void
2221 ttwwakeup(struct tty *tp)
2222 {
2223
2224         if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
2225                 pgsigio(tp->t_sigio, SIGIO, (tp->t_session != NULL));
2226         if (ISSET(tp->t_state, TS_BUSY | TS_SO_OCOMPLETE) ==
2227             TS_SO_OCOMPLETE && tp->t_outq.c_cc == 0) {
2228                 CLR(tp->t_state, TS_SO_OCOMPLETE);
2229                 wakeup(TSA_OCOMPLETE(tp));
2230         }
2231         if (ISSET(tp->t_state, TS_SO_OLOWAT) &&
2232             tp->t_outq.c_cc <= tp->t_olowat) {
2233                 CLR(tp->t_state, TS_SO_OLOWAT);
2234                 wakeup(TSA_OLOWAT(tp));
2235         }
2236         KNOTE(&tp->t_wkq.ki_note, 0);
2237 }
2238
2239 /*
2240  * Look up a code for a specified speed in a conversion table;
2241  * used by drivers to map software speed values to hardware parameters.
2242  */
2243 int
2244 ttspeedtab(int speed, struct speedtab *table)
2245 {
2246
2247         for ( ; table->sp_speed != -1; table++)
2248                 if (table->sp_speed == speed)
2249                         return (table->sp_code);
2250         return (-1);
2251 }
2252
2253 /*
2254  * Set input and output watermarks and buffer sizes.  For input, the
2255  * high watermark is about one second's worth of input above empty, the
2256  * low watermark is slightly below high water, and the buffer size is a
2257  * driver-dependent amount above high water.  For output, the watermarks
2258  * are near the ends of the buffer, with about 1 second's worth of input
2259  * between them.  All this only applies to the standard line discipline.
2260  */
2261 void
2262 ttsetwater(struct tty *tp)
2263 {
2264         int cps, ttmaxhiwat, x;
2265
2266         /* Input. */
2267         clist_alloc_cblocks(&tp->t_canq, TTYHOG, 512);
2268         switch (tp->t_ispeedwat) {
2269         case (speed_t)-1:
2270                 cps = tp->t_ispeed / 10;
2271                 break;
2272         case 0:
2273                 /*
2274                  * This case is for old drivers that don't know about
2275                  * t_ispeedwat.  Arrange for them to get the old buffer
2276                  * sizes and watermarks.
2277                  */
2278                 cps = TTYHOG - 2 * 256;
2279                 tp->t_ififosize = 2 * 2048;
2280                 break;
2281         default:
2282                 cps = tp->t_ispeedwat / 10;
2283                 break;
2284         }
2285         tp->t_ihiwat = cps;
2286         tp->t_ilowat = 7 * cps / 8;
2287         x = cps + tp->t_ififosize;
2288         clist_alloc_cblocks(&tp->t_rawq, x, x);
2289
2290         /* Output. */
2291         switch (tp->t_ospeedwat) {
2292         case (speed_t)-1:
2293                 cps = tp->t_ospeed / 10;
2294                 ttmaxhiwat = 2 * TTMAXHIWAT;
2295                 break;
2296         case 0:
2297                 cps = tp->t_ospeed / 10;
2298                 ttmaxhiwat = TTMAXHIWAT;
2299                 break;
2300         default:
2301                 cps = tp->t_ospeedwat / 10;
2302                 ttmaxhiwat = 8 * TTMAXHIWAT;
2303                 break;
2304         }
2305 #define CLAMP(x, h, l)  ((x) > h ? h : ((x) < l) ? l : (x))
2306         tp->t_olowat = x = CLAMP(cps / 2, TTMAXLOWAT, TTMINLOWAT);
2307         x += cps;
2308         x = CLAMP(x, ttmaxhiwat, TTMINHIWAT);   /* XXX clamps are too magic */
2309         tp->t_ohiwat = roundup(x, CBSIZE);      /* XXX for compat */
2310         x = imax(tp->t_ohiwat, TTMAXHIWAT);     /* XXX for compat/safety */
2311         x += OBUFSIZ + 100;
2312         clist_alloc_cblocks(&tp->t_outq, x, x);
2313 #undef  CLAMP
2314 }
2315
2316 /*
2317  * Report on state of foreground process group.
2318  */
2319 void
2320 ttyinfo(struct tty *tp)
2321 {
2322         struct proc *p, *pick;
2323         struct lwp *lp;
2324         struct rusage ru;
2325         int tmp;
2326
2327         if (ttycheckoutq(tp,0) == 0)
2328                 return;
2329
2330         /*
2331          * We always print the load average, then figure out what else to
2332          * print based on the state of the current process group.
2333          */
2334         tmp = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
2335         ttyprintf(tp, "load: %d.%02d ", tmp / 100, tmp % 100);
2336
2337         if (tp->t_session == NULL) {
2338                 ttyprintf(tp, "not a controlling terminal\n");
2339         } else if (tp->t_pgrp == NULL) {
2340                 ttyprintf(tp, "no foreground process group\n");
2341         } else if ((p = LIST_FIRST(&tp->t_pgrp->pg_members)) == 0) {
2342                 ttyprintf(tp, "empty foreground process group\n");
2343         } else {
2344                 /*
2345                  * Pick an interesting process.  Note that certain elements,
2346                  * in particular the wmesg, require a critical section for
2347                  * safe access (YYY and we are still not MP safe).
2348                  *
2349                  * NOTE: lwp_wmesg is lwp_thread->td_wmesg.
2350                  */
2351                 char buf[64];
2352                 const char *str;
2353                 long vmsz;
2354                 int pctcpu;
2355
2356                 crit_enter();
2357
2358                 /* XXX lwp should compare lwps */
2359
2360                 for (pick = NULL; p != 0; p = LIST_NEXT(p, p_pglist)) {
2361                         if (proc_compare(pick, p))
2362                                 pick = p;
2363                 }
2364
2365                 /* XXX lwp */
2366                 lp = FIRST_LWP_IN_PROC(pick);
2367                 if (lp == NULL) {
2368                         ttyprintf(tp, "foreground process without lwp\n");
2369                         tp->t_rocount = 0;
2370                         crit_exit();
2371                         return;
2372                 }
2373
2374                 /*
2375                  * Figure out what wait/process-state message, and command
2376                  * buffer to present
2377                  */
2378                 /*
2379                  * XXX lwp This is a horrible mixture.  We need to rework this
2380                  * as soon as lwps have their own runnable status.
2381                  */
2382                 if (pick->p_flag & P_WEXIT)
2383                         str = "exiting";
2384                 else if (lp->lwp_stat == LSRUN)
2385                         str = "running";
2386                 else if (pick->p_stat == SIDL)
2387                         str = "spawning";
2388                 else if (lp->lwp_wmesg) /* lwp_thread must not be NULL */
2389                         str = lp->lwp_wmesg;
2390                 else
2391                         str = "iowait";
2392
2393                 ksnprintf(buf, sizeof(buf), "cmd: %s %d [%s]",
2394                         pick->p_comm, pick->p_pid, str);
2395
2396                 /*
2397                  * Calculate cpu usage, percent cpu, and cmsz.  Note that
2398                  * 'pick' becomes invalid the moment we exit the critical
2399                  * section.
2400                  */
2401                 if (lp->lwp_thread && (pick->p_flag & P_SWAPPEDOUT) == 0)
2402                         calcru_proc(pick, &ru);
2403
2404                 pctcpu = (lp->lwp_pctcpu * 10000 + FSCALE / 2) >> FSHIFT;
2405
2406                 if (pick->p_stat == SIDL || pick->p_stat == SZOMB)
2407                     vmsz = 0;
2408                 else
2409                     vmsz = pgtok(vmspace_resident_count(pick->p_vmspace));
2410
2411                 crit_exit();
2412
2413                 /*
2414                  * Dump the output
2415                  */
2416                 ttyprintf(tp, " %s ", buf);
2417                 ttyprintf(tp, "%ld.%02ldu ",
2418                         ru.ru_utime.tv_sec, ru.ru_utime.tv_usec / 10000);
2419                 ttyprintf(tp, "%ld.%02lds ",
2420                         ru.ru_stime.tv_sec, ru.ru_stime.tv_usec / 10000);
2421                 ttyprintf(tp, "%d%% %ldk\n", pctcpu / 100, vmsz);
2422         }
2423         tp->t_rocount = 0;      /* so pending input will be retyped if BS */
2424 }
2425
2426 /*
2427  * Returns 1 if p2 is "better" than p1
2428  *
2429  * The algorithm for picking the "interesting" process is thus:
2430  *
2431  *      1) Only foreground processes are eligible - implied.
2432  *      2) Runnable processes are favored over anything else.  The runner
2433  *         with the highest cpu utilization is picked (p_cpticks).  Ties are
2434  *         broken by picking the highest pid.
2435  *      3) The sleeper with the shortest sleep time is next.  With ties,
2436  *         we pick out just "short-term" sleepers (LWP_SINTR == 0).
2437  *      4) Further ties are broken by picking the highest pid.
2438  */
2439 #define ISRUN(lp)       ((lp)->lwp_stat == LSRUN)
2440 #define TESTAB(a, b)    ((a)<<1 | (b))
2441 #define ONLYA   2
2442 #define ONLYB   1
2443 #define BOTH    3
2444
2445 static int
2446 proc_compare(struct proc *p1, struct proc *p2)
2447 {
2448         struct lwp *lp1, *lp2;
2449         if (p1 == NULL)
2450                 return (1);
2451
2452         /*
2453          * weed out zombies
2454          */
2455         switch (TESTAB(p1->p_stat == SZOMB, p2->p_stat == SZOMB)) {
2456         case ONLYA:
2457                 return (1);
2458         case ONLYB:
2459                 return (0);
2460         case BOTH:
2461                 return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
2462         }
2463
2464         /* XXX lwp */
2465         lp1 = FIRST_LWP_IN_PROC(p1);
2466         lp2 = FIRST_LWP_IN_PROC(p2);
2467
2468         /*
2469          * see if at least one of them is runnable
2470          */
2471         switch (TESTAB(ISRUN(lp1), ISRUN(lp2))) {
2472         case ONLYA:
2473                 return (0);
2474         case ONLYB:
2475                 return (1);
2476         case BOTH:
2477                 /*
2478                  * tie - favor one with highest recent cpu utilization
2479                  */
2480                 if (lp2->lwp_cpticks > lp1->lwp_cpticks)
2481                         return (1);
2482                 if (lp1->lwp_cpticks > lp2->lwp_cpticks)
2483                         return (0);
2484                 return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
2485         }
2486         /*
2487          * pick the one with the smallest sleep time
2488          */
2489         if (lp2->lwp_slptime > lp1->lwp_slptime)
2490                 return (0);
2491         if (lp1->lwp_slptime > lp2->lwp_slptime)
2492                 return (1);
2493         /*
2494          * favor one sleeping in a non-interruptible sleep
2495          */
2496         if (lp1->lwp_flag & LWP_SINTR && (lp2->lwp_flag & LWP_SINTR) == 0)
2497                 return (1);
2498         if (lp2->lwp_flag & LWP_SINTR && (lp1->lwp_flag & LWP_SINTR) == 0)
2499                 return (0);
2500         return (p2->p_pid > p1->p_pid);         /* tie - return highest pid */
2501 }
2502
2503 /*
2504  * Output char to tty; console putchar style.
2505  */
2506 int
2507 tputchar(int c, struct tty *tp)
2508 {
2509         crit_enter();
2510         if (!ISSET(tp->t_state, TS_CONNECTED)) {
2511                 crit_exit();
2512                 return (-1);
2513         }
2514         if (c == '\n')
2515                 (void)ttyoutput('\r', tp);
2516         (void)ttyoutput(c, tp);
2517         ttstart(tp);
2518         crit_exit();
2519         return (0);
2520 }
2521
2522 /*
2523  * Sleep on chan, returning ERESTART if tty changed while we napped and
2524  * returning any errors (e.g. EINTR/EWOULDBLOCK) reported by tsleep.  If
2525  * the tty is revoked, restarting a pending call will redo validation done
2526  * at the start of the call.
2527  */
2528 int
2529 ttysleep(struct tty *tp, void *chan, int slpflags, char *wmesg, int timo)
2530 {
2531         int error;
2532         int gen;
2533
2534         gen = tp->t_gen;
2535         error = tsleep(chan, slpflags, wmesg, timo);
2536         if (error)
2537                 return (error);
2538         return (tp->t_gen == gen ? 0 : ERESTART);
2539 }
2540
2541 /*
2542  * Revoke a tty.
2543  *
2544  * We bump the gen to force any ttysleep()'s to return with ERESTART
2545  * and flush the tty.  The related fp's should already have been
2546  * replaced so the tty will close when the last references on the
2547  * original fp's go away.
2548  */
2549 int
2550 ttyrevoke(struct dev_revoke_args *ap)
2551 {
2552         struct tty *tp;
2553
2554         tp = ap->a_head.a_dev->si_tty;
2555         tp->t_gen++;
2556         ttyflush(tp, FREAD | FWRITE);
2557         wakeup(TSA_CARR_ON(tp));
2558         ttwakeup(tp);
2559         ttwwakeup(tp);
2560         return (0);
2561 }
2562
2563 /*
2564  * Allocate a tty struct.  Clists in the struct will be allocated by
2565  * ttyopen().
2566  */
2567 struct tty *
2568 ttymalloc(struct tty *tp)
2569 {
2570
2571         if (tp) {
2572                 return(tp);
2573         }
2574         tp = kmalloc(sizeof *tp, M_TTYS, M_WAITOK|M_ZERO);
2575         ttyregister(tp);
2576         return (tp);
2577 }
2578
2579 void
2580 ttyunregister(struct tty *tp)
2581 {
2582         KKASSERT(ISSET(tp->t_state, TS_REGISTERED));
2583         CLR(tp->t_state, TS_REGISTERED);
2584         TAILQ_REMOVE(&tty_list, tp, t_list);
2585 }
2586
2587 void
2588 ttyregister(struct tty *tp)
2589 {
2590         KKASSERT(!ISSET(tp->t_state, TS_REGISTERED));
2591         SET(tp->t_state, TS_REGISTERED);
2592         TAILQ_INSERT_HEAD(&tty_list, tp, t_list);
2593 }
2594
2595 static int
2596 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
2597 {
2598         int error;
2599         struct tty *tp;
2600         struct tty t;
2601         struct tty marker;
2602
2603         bzero(&marker, sizeof(marker));
2604         marker.t_state = TS_MARKER;
2605         error = 0;
2606
2607         TAILQ_INSERT_HEAD(&tty_list, &marker, t_list);
2608         while ((tp = TAILQ_NEXT(&marker, t_list)) != NULL) {
2609                 TAILQ_REMOVE(&tty_list, &marker, t_list);
2610                 TAILQ_INSERT_AFTER(&tty_list, tp, &marker, t_list);
2611                 if (tp->t_state & TS_MARKER)
2612                         continue;
2613                 t = *tp;
2614                 if (t.t_dev)
2615                         t.t_dev = (cdev_t)(uintptr_t)dev2udev(t.t_dev);
2616                 error = SYSCTL_OUT(req, (caddr_t)&t, sizeof(t));
2617                 if (error)
2618                         break;
2619         }
2620         TAILQ_REMOVE(&tty_list, &marker, t_list);
2621         return (error);
2622 }
2623
2624 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD,
2625         0, 0, sysctl_kern_ttys, "S,tty", "All struct ttys");
2626
2627 void
2628 nottystop(struct tty *tp, int rw)
2629 {
2630
2631         return;
2632 }
2633
2634 int
2635 ttyread(struct dev_read_args *ap)
2636 {
2637         struct tty *tp;
2638
2639         tp = ap->a_head.a_dev->si_tty;
2640         if (tp == NULL)
2641                 return (ENODEV);
2642         return ((*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag));
2643 }
2644
2645 int
2646 ttywrite(struct dev_write_args *ap)
2647 {
2648         struct tty *tp;
2649
2650         tp = ap->a_head.a_dev->si_tty;
2651         if (tp == NULL)
2652                 return (ENODEV);
2653         return ((*linesw[tp->t_line].l_write)(tp, ap->a_uio, ap->a_ioflag));
2654 }