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.
   5  * All or some portions of this file are derived from material licensed
   6  * to the University of California by American Telephone and Telegraph
   7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   8  * the permission of UNIX System Laboratories, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)tty.c       8.8 (Berkeley) 1/21/94
  39  * $FreeBSD: src/sys/kern/tty.c,v 1.129.2.5 2002/03/11 01:32:31 dd Exp $
  40  * $DragonFly: src/sys/kern/tty.c,v 1.46 2008/09/10 09:50:09 y0netan1 Exp $
  41  */
  42
  43 /*-
  44  * TODO:
  45  *      o Fix races for sending the start char in ttyflush().
  46  *      o Handle inter-byte timeout for "MIN > 0, TIME > 0" in ttyselect().
  47  *        With luck, there will be MIN chars before select() returns().
  48  *      o Handle CLOCAL consistently for ptys.  Perhaps disallow setting it.
  49  *      o Don't allow input in TS_ZOMBIE case.  It would be visible through
  50  *        FIONREAD.
  51  *      o Do the new sio locking stuff here and use it to avoid special
  52  *        case for EXTPROC?
  53  *      o Lock PENDIN too?
  54  *      o Move EXTPROC and/or PENDIN to t_state?
  55  *      o Wrap most of ttioctl in spltty/splx.
  56  *      o Implement TIOCNOTTY or remove it from <sys/ioctl.h>.
  57  *      o Send STOP if IXOFF is toggled off while TS_TBLOCK is set.
  58  *      o Don't allow certain termios flags to affect disciplines other
  59  *        than TTYDISC.  Cancel their effects before switch disciplines
  60  *        and ignore them if they are set while we are in another
  61  *        discipline.
  62  *      o Now that historical speed conversions are handled here, don't
  63  *        do them in drivers.
  64  *      o Check for TS_CARR_ON being set while everything is closed and not
  65  *        waiting for carrier.  TS_CARR_ON isn't cleared if nothing is open,
  66  *        so it would live until the next open even if carrier drops.
  67  *      o Restore TS_WOPEN since it is useful in pstat.  It must be cleared
  68  *        only when _all_ openers leave open().
  69  */
  70
  71 #include "opt_compat.h"
  72 #include "opt_uconsole.h"
  73
  74 #include <sys/param.h>
  75 #include <sys/systm.h>
  76 #include <sys/filio.h>
  77 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
  78 #include <sys/ioctl_compat.h>
  79 #endif
  80 #include <sys/proc.h>
  81 #include <sys/priv.h>
  82 #define TTYDEFCHARS
  83 #include <sys/tty.h>
  84 #include <sys/clist.h>
  85 #undef  TTYDEFCHARS
  86 #include <sys/fcntl.h>
  87 #include <sys/conf.h>
  88 #include <sys/dkstat.h>
  89 #include <sys/poll.h>
  90 #include <sys/kernel.h>
  91 #include <sys/vnode.h>
  92 #include <sys/signalvar.h>
  93 #include <sys/signal2.h>
  94 #include <sys/resourcevar.h>
  95 #include <sys/malloc.h>
  96 #include <sys/filedesc.h>
  97 #include <sys/sysctl.h>
  98 #include <sys/thread2.h>
  99
 100 #include <vm/vm.h>
 101 #include <sys/lock.h>
 102 #include <vm/pmap.h>
 103 #include <vm/vm_map.h>
 104
 105 MALLOC_DEFINE(M_TTYS, "ttys", "tty data structures");
 106
 107 static int      proc_compare (struct proc *p1, struct proc *p2);
 108 static int      ttnread (struct tty *tp);
 109 static void     ttyecho (int c, struct tty *tp);
 110 static int      ttyoutput (int c, struct tty *tp);
 111 static void     ttypend (struct tty *tp);
 112 static void     ttyretype (struct tty *tp);
 113 static void     ttyrub (int c, struct tty *tp);
 114 static void     ttyrubo (struct tty *tp, int cnt);
 115 static void     ttyunblock (struct tty *tp);
 116 static int      ttywflush (struct tty *tp);
 117 static int      filt_ttyread (struct knote *kn, long hint);
 118 static void     filt_ttyrdetach (struct knote *kn);
 119 static int      filt_ttywrite (struct knote *kn, long hint);
 120 static void     filt_ttywdetach (struct knote *kn);
 121
 122 /*
 123  * Table with character classes and parity. The 8th bit indicates parity,
 124  * the 7th bit indicates the character is an alphameric or underscore (for
 125  * ALTWERASE), and the low 6 bits indicate delay type.  If the low 6 bits
 126  * are 0 then the character needs no special processing on output; classes
 127  * other than 0 might be translated or (not currently) require delays.
 128  */
 129 #define E       0x00    /* Even parity. */
 130 #define O       0x80    /* Odd parity. */
 131 #define PARITY(c)       (char_type[c] & O)
 132
 133 #define ALPHA   0x40    /* Alpha or underscore. */
 134 #define ISALPHA(c)      (char_type[(c) & TTY_CHARMASK] & ALPHA)
 135
 136 #define CCLASSMASK      0x3f
 137 #define CCLASS(c)       (char_type[c] & CCLASSMASK)
 138
 139 #define BS      BACKSPACE
 140 #define CC      CONTROL
 141 #define CR      RETURN
 142 #define NA      ORDINARY | ALPHA
 143 #define NL      NEWLINE
 144 #define NO      ORDINARY
 145 #define TB      TAB
 146 #define VT      VTAB
 147
 148 static u_char const char_type[] = {
 149         E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* nul - bel */
 150         O|BS, E|TB, E|NL, O|CC, E|VT, O|CR, O|CC, E|CC, /* bs - si */
 151         O|CC, E|CC, E|CC, O|CC, E|CC, O|CC, O|CC, E|CC, /* dle - etb */
 152         E|CC, O|CC, O|CC, E|CC, O|CC, E|CC, E|CC, O|CC, /* can - us */
 153         O|NO, E|NO, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* sp - ' */
 154         E|NO, O|NO, O|NO, E|NO, O|NO, E|NO, E|NO, O|NO, /* ( - / */
 155         E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* 0 - 7 */
 156         O|NA, E|NA, E|NO, O|NO, E|NO, O|NO, O|NO, E|NO, /* 8 - ? */
 157         O|NO, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* @ - G */
 158         E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* H - O */
 159         E|NA, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* P - W */
 160         O|NA, E|NA, E|NA, O|NO, E|NO, O|NO, O|NO, O|NA, /* X - _ */
 161         E|NO, O|NA, O|NA, E|NA, O|NA, E|NA, E|NA, O|NA, /* ` - g */
 162         O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* h - o */
 163         O|NA, E|NA, E|NA, O|NA, E|NA, O|NA, O|NA, E|NA, /* p - w */
 164         E|NA, O|NA, O|NA, E|NO, O|NO, E|NO, E|NO, O|CC, /* x - del */
 165         /*
 166          * Meta chars; should be settable per character set;
 167          * for now, treat them all as normal characters.
 168          */
 169         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 170         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 171         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 172         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 173         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 174         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 175         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 176         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 177         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 178         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 179         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 180         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 181         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 182         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 183         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 184         NA,   NA,   NA,   NA,   NA,   NA,   NA,   NA,
 185 };
 186 #undef  BS
 187 #undef  CC
 188 #undef  CR
 189 #undef  NA
 190 #undef  NL
 191 #undef  NO
 192 #undef  TB
 193 #undef  VT
 194
 195 /* Macros to clear/set/test flags. */
 196 #define SET(t, f)       (t) |= (f)
 197 #define CLR(t, f)       (t) &= ~(f)
 198 #define ISSET(t, f)     ((t) & (f))
 199
 200 #undef MAX_INPUT                /* XXX wrong in <sys/syslimits.h> */
 201 #define MAX_INPUT       TTYHOG  /* XXX limit is usually larger for !ICANON */
 202
 203 uint64_t tk_nin;
 204 SYSCTL_OPAQUE(_kern, OID_AUTO, tk_nin, CTLFLAG_RD, &tk_nin, sizeof(tk_nin),
 205     "LU", "TTY input statistic");
 206 uint64_t tk_nout;
 207 SYSCTL_OPAQUE(_kern, OID_AUTO, tk_nout, CTLFLAG_RD, &tk_nout, sizeof(tk_nout),
 208     "LU", "TTY output statistic");
 209 uint64_t tk_rawcc;
 210
 211 /*
 212  * list of struct tty where pstat(8) can pick it up with sysctl
 213  */
 214 static SLIST_HEAD(, tty) tty_list;
 215
 216 /*
 217  * Initial open of tty, or (re)entry to standard tty line discipline.
 218  */
 219 int
 220 ttyopen(cdev_t device, struct tty *tp)
 221 {
 222         crit_enter();
 223         tp->t_dev = device;
 224         if (!ISSET(tp->t_state, TS_ISOPEN)) {
 225                 SET(tp->t_state, TS_ISOPEN);
 226                 if (ISSET(tp->t_cflag, CLOCAL))
 227                         SET(tp->t_state, TS_CONNECTED);
 228                 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 = 0;
 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                 if (dorevoke)
 345                         VOP_REVOKE(vp, REVOKEALL);
 346                 vn_unlock(vp);
 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 #ifdef TIOCHPCL
 936         case TIOCHPCL:                  /* hang up on last close */
 937                 crit_enter();
 938                 SET(tp->t_cflag, HUPCL);
 939                 crit_exit();
 940                 break;
 941 #endif
 942         case TIOCNXCL:                  /* reset exclusive use of tty */
 943                 crit_enter();
 944                 CLR(tp->t_state, TS_XCLUDE);
 945                 crit_exit();
 946                 break;
 947         case TIOCOUTQ:                  /* output queue size */
 948                 *(int *)data = tp->t_outq.c_cc;
 949                 break;
 950         case TIOCSETA:                  /* set termios struct */
 951         case TIOCSETAW:                 /* drain output, set */
 952         case TIOCSETAF: {               /* drn out, fls in, set */
 953                 struct termios *t = (struct termios *)data;
 954
 955                 if (t->c_ispeed == 0)
 956                         t->c_ispeed = t->c_ospeed;
 957                 if (t->c_ispeed == 0)
 958                         t->c_ispeed = tp->t_ospeed;
 959                 if (t->c_ispeed == 0)
 960                         return (EINVAL);
 961                 crit_enter();
 962                 if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
 963                         error = ttywait(tp);
 964                         if (error) {
 965                                 crit_exit();
 966                                 return (error);
 967                         }
 968                         if (cmd == TIOCSETAF)
 969                                 ttyflush(tp, FREAD);
 970                 }
 971                 if (!ISSET(t->c_cflag, CIGNORE)) {
 972                         /*
 973                          * Set device hardware.
 974                          */
 975                         if (tp->t_param && (error = (*tp->t_param)(tp, t))) {
 976                                 crit_exit();
 977                                 return (error);
 978                         }
 979                         if (ISSET(t->c_cflag, CLOCAL) &&
 980                             !ISSET(tp->t_cflag, CLOCAL)) {
 981                                 /*
 982                                  * XXX disconnections would be too hard to
 983                                  * get rid of without this kludge.  The only
 984                                  * way to get rid of controlling terminals
 985                                  * is to exit from the session leader.
 986                                  */
 987                                 CLR(tp->t_state, TS_ZOMBIE);
 988
 989                                 wakeup(TSA_CARR_ON(tp));
 990                                 ttwakeup(tp);
 991                                 ttwwakeup(tp);
 992                         }
 993                         if ((ISSET(tp->t_state, TS_CARR_ON) ||
 994                              ISSET(t->c_cflag, CLOCAL)) &&
 995                             !ISSET(tp->t_state, TS_ZOMBIE))
 996                                 SET(tp->t_state, TS_CONNECTED);
 997                         else
 998                                 CLR(tp->t_state, TS_CONNECTED);
 999                         tp->t_cflag = t->c_cflag;
1000                         tp->t_ispeed = t->c_ispeed;
1001                         if (t->c_ospeed != 0)
1002                                 tp->t_ospeed = t->c_ospeed;
1003                         ttsetwater(tp);
1004                 }
1005                 if (ISSET(t->c_lflag, ICANON) != ISSET(tp->t_lflag, ICANON) &&
1006                     cmd != TIOCSETAF) {
1007                         if (ISSET(t->c_lflag, ICANON))
1008                                 SET(tp->t_lflag, PENDIN);
1009                         else {
1010                                 /*
1011                                  * XXX we really shouldn't allow toggling
1012                                  * ICANON while we're in a non-termios line
1013                                  * discipline.  Now we have to worry about
1014                                  * panicing for a null queue.
1015                                  */
1016                                 if (tp->t_canq.c_cbreserved > 0 &&
1017                                     tp->t_rawq.c_cbreserved > 0) {
1018                                         catq(&tp->t_rawq, &tp->t_canq);
1019                                         /*
1020                                          * XXX the queue limits may be
1021                                          * different, so the old queue
1022                                          * swapping method no longer works.
1023                                          */
1024                                         catq(&tp->t_canq, &tp->t_rawq);
1025                                 }
1026                                 CLR(tp->t_lflag, PENDIN);
1027                         }
1028                         ttwakeup(tp);
1029                 }
1030                 tp->t_iflag = t->c_iflag;
1031                 tp->t_oflag = t->c_oflag;
1032                 /*
1033                  * Make the EXTPROC bit read only.
1034                  */
1035                 if (ISSET(tp->t_lflag, EXTPROC))
1036                         SET(t->c_lflag, EXTPROC);
1037                 else
1038                         CLR(t->c_lflag, EXTPROC);
1039                 tp->t_lflag = t->c_lflag | ISSET(tp->t_lflag, PENDIN);
1040                 if (t->c_cc[VMIN] != tp->t_cc[VMIN] ||
1041                     t->c_cc[VTIME] != tp->t_cc[VTIME])
1042                         ttwakeup(tp);
1043                 bcopy(t->c_cc, tp->t_cc, sizeof(t->c_cc));
1044                 crit_exit();
1045                 break;
1046         }
1047         case TIOCSETD: {                /* set line discipline */
1048                 int t = *(int *)data;
1049                 cdev_t device = tp->t_dev;
1050
1051                 if ((u_int)t >= nlinesw)
1052                         return (ENXIO);
1053                 if (t != tp->t_line) {
1054                         crit_enter();
1055                         (*linesw[tp->t_line].l_close)(tp, flag);
1056                         error = (*linesw[t].l_open)(device, tp);
1057                         if (error) {
1058                                 (void)(*linesw[tp->t_line].l_open)(device, tp);
1059                                 crit_exit();
1060                                 return (error);
1061                         }
1062                         tp->t_line = t;
1063                         crit_exit();
1064                 }
1065                 break;
1066         }
1067         case TIOCSTART:                 /* start output, like ^Q */
1068                 crit_enter();
1069                 if (ISSET(tp->t_state, TS_TTSTOP) ||
1070                     ISSET(tp->t_lflag, FLUSHO)) {
1071                         CLR(tp->t_lflag, FLUSHO);
1072                         CLR(tp->t_state, TS_TTSTOP);
1073                         ttstart(tp);
1074                 }
1075                 crit_exit();
1076                 break;
1077         case TIOCSTI:                   /* simulate terminal input */
1078                 if ((flag & FREAD) == 0 && priv_check(td, PRIV_ROOT))
1079                         return (EPERM);
1080                 if (!isctty(p, tp) && priv_check(td, PRIV_ROOT))
1081                         return (EACCES);
1082                 crit_enter();
1083                 (*linesw[tp->t_line].l_rint)(*(u_char *)data, tp);
1084                 crit_exit();
1085                 break;
1086         case TIOCSTOP:                  /* stop output, like ^S */
1087                 crit_enter();
1088                 if (!ISSET(tp->t_state, TS_TTSTOP)) {
1089                         SET(tp->t_state, TS_TTSTOP);
1090                         (*tp->t_stop)(tp, 0);
1091                 }
1092                 crit_exit();
1093                 break;
1094         case TIOCSCTTY:                 /* become controlling tty */
1095                 /* Session ctty vnode pointer set in vnode layer. */
1096                 if (!SESS_LEADER(p) ||
1097                     ((p->p_session->s_ttyvp || tp->t_session) &&
1098                     (tp->t_session != p->p_session)))
1099                         return (EPERM);
1100                 tp->t_session = p->p_session;
1101                 tp->t_pgrp = p->p_pgrp;
1102                 p->p_session->s_ttyp = tp;
1103                 p->p_flag |= P_CONTROLT;
1104                 break;
1105         case TIOCSPGRP: {               /* set pgrp of tty */
1106                 struct pgrp *pgrp = pgfind(*(int *)data);
1107
1108                 if (!isctty(p, tp))
1109                         return (ENOTTY);
1110                 else if (pgrp == NULL || pgrp->pg_session != p->p_session)
1111                         return (EPERM);
1112                 tp->t_pgrp = pgrp;
1113                 break;
1114         }
1115         case TIOCSTAT:                  /* simulate control-T */
1116                 crit_enter();
1117                 ttyinfo(tp);
1118                 crit_exit();
1119                 break;
1120         case TIOCSWINSZ:                /* set window size */
1121                 if (bcmp((caddr_t)&tp->t_winsize, data,
1122                     sizeof (struct winsize))) {
1123                         tp->t_winsize = *(struct winsize *)data;
1124                         pgsignal(tp->t_pgrp, SIGWINCH, 1);
1125                 }
1126                 break;
1127         case TIOCSDRAINWAIT:
1128                 error = priv_check(td, PRIV_ROOT);
1129                 if (error)
1130                         return (error);
1131                 tp->t_timeout = *(int *)data * hz;
1132                 wakeup(TSA_OCOMPLETE(tp));
1133                 wakeup(TSA_OLOWAT(tp));
1134                 break;
1135         case TIOCGDRAINWAIT:
1136                 *(int *)data = tp->t_timeout / hz;
1137                 break;
1138         default:
1139 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
1140                 return (ttcompat(tp, cmd, data, flag));
1141 #else
1142                 return (ENOIOCTL);
1143 #endif
1144         }
1145         return (0);
1146 }
1147
1148 int
1149 ttypoll(struct dev_poll_args *ap)
1150 {
1151         cdev_t dev = ap->a_head.a_dev;
1152         int events = ap->a_events;
1153         int revents = 0;
1154         struct tty *tp;
1155
1156         tp = dev->si_tty;
1157         /* XXX used to return ENXIO, but that means true! */
1158         if (tp == NULL) {
1159                 ap->a_events = (events & (POLLIN | POLLOUT | POLLRDNORM |
1160                                 POLLWRNORM)) | POLLHUP;
1161                 return(0);
1162         }
1163
1164         crit_enter();
1165         if (events & (POLLIN | POLLRDNORM)) {
1166                 if (ttnread(tp) > 0 || ISSET(tp->t_state, TS_ZOMBIE))
1167                         revents |= events & (POLLIN | POLLRDNORM);
1168                 else
1169                         selrecord(curthread, &tp->t_rsel);
1170         }
1171         if (events & (POLLOUT | POLLWRNORM)) {
1172                 if ((tp->t_outq.c_cc <= tp->t_olowat &&
1173                      ISSET(tp->t_state, TS_CONNECTED))
1174                     || ISSET(tp->t_state, TS_ZOMBIE))
1175                         revents |= events & (POLLOUT | POLLWRNORM);
1176                 else
1177                         selrecord(curthread, &tp->t_wsel);
1178         }
1179         crit_exit();
1180         ap->a_events = revents;
1181         return (0);
1182 }
1183
1184 static struct filterops ttyread_filtops =
1185         { 1, NULL, filt_ttyrdetach, filt_ttyread };
1186 static struct filterops ttywrite_filtops =
1187         { 1, NULL, filt_ttywdetach, filt_ttywrite };
1188
1189 int
1190 ttykqfilter(struct dev_kqfilter_args *ap)
1191 {
1192         cdev_t dev = ap->a_head.a_dev;
1193         struct knote *kn = ap->a_kn;
1194         struct tty *tp = dev->si_tty;
1195         struct klist *klist;
1196
1197         ap->a_result = 0;
1198         switch (kn->kn_filter) {
1199         case EVFILT_READ:
1200                 klist = &tp->t_rsel.si_note;
1201                 kn->kn_fop = &ttyread_filtops;
1202                 break;
1203         case EVFILT_WRITE:
1204                 klist = &tp->t_wsel.si_note;
1205                 kn->kn_fop = &ttywrite_filtops;
1206                 break;
1207         default:
1208                 ap->a_result = 1;
1209                 return (0);
1210         }
1211
1212         kn->kn_hook = (caddr_t)dev;
1213
1214         crit_enter();
1215         SLIST_INSERT_HEAD(klist, kn, kn_selnext);
1216         crit_exit();
1217
1218         return (0);
1219 }
1220
1221 static void
1222 filt_ttyrdetach(struct knote *kn)
1223 {
1224         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1225
1226         crit_enter();
1227         SLIST_REMOVE(&tp->t_rsel.si_note, kn, knote, kn_selnext);
1228         crit_exit();
1229 }
1230
1231 static int
1232 filt_ttyread(struct knote *kn, long hint)
1233 {
1234         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1235
1236         kn->kn_data = ttnread(tp);
1237         if (ISSET(tp->t_state, TS_ZOMBIE)) {
1238                 kn->kn_flags |= EV_EOF;
1239                 return (1);
1240         }
1241         return (kn->kn_data > 0);
1242 }
1243
1244 static void
1245 filt_ttywdetach(struct knote *kn)
1246 {
1247         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1248
1249         crit_enter();
1250         SLIST_REMOVE(&tp->t_wsel.si_note, kn, knote, kn_selnext);
1251         crit_exit();
1252 }
1253
1254 static int
1255 filt_ttywrite(struct knote *kn, long hint)
1256 {
1257         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
1258
1259         kn->kn_data = tp->t_outq.c_cc;
1260         if (ISSET(tp->t_state, TS_ZOMBIE))
1261                 return (1);
1262         return (kn->kn_data <= tp->t_olowat &&
1263             ISSET(tp->t_state, TS_CONNECTED));
1264 }
1265
1266 /*
1267  * Must be called while in a critical section.
1268  */
1269 static int
1270 ttnread(struct tty *tp)
1271 {
1272         int nread;
1273
1274         if (ISSET(tp->t_lflag, PENDIN))
1275                 ttypend(tp);
1276         nread = tp->t_canq.c_cc;
1277         if (!ISSET(tp->t_lflag, ICANON)) {
1278                 nread += tp->t_rawq.c_cc;
1279                 if (nread < tp->t_cc[VMIN] && tp->t_cc[VTIME] == 0)
1280                         nread = 0;
1281         }
1282         return (nread);
1283 }
1284
1285 /*
1286  * Wait for output to drain.
1287  */
1288 int
1289 ttywait(struct tty *tp)
1290 {
1291         int error;
1292
1293         error = 0;
1294         crit_enter();
1295         while ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1296                ISSET(tp->t_state, TS_CONNECTED) && tp->t_oproc) {
1297                 (*tp->t_oproc)(tp);
1298                 if ((tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)) &&
1299                     ISSET(tp->t_state, TS_CONNECTED)) {
1300                         SET(tp->t_state, TS_SO_OCOMPLETE);
1301                         error = ttysleep(tp, TSA_OCOMPLETE(tp),
1302                                          PCATCH, "ttywai",
1303                                          tp->t_timeout);
1304                         if (error) {
1305                                 if (error == EWOULDBLOCK)
1306                                         error = EIO;
1307                                 break;
1308                         }
1309                 } else
1310                         break;
1311         }
1312         if (!error && (tp->t_outq.c_cc || ISSET(tp->t_state, TS_BUSY)))
1313                 error = EIO;
1314         crit_exit();
1315         return (error);
1316 }
1317
1318 /*
1319  * Flush if successfully wait.
1320  */
1321 static int
1322 ttywflush(struct tty *tp)
1323 {
1324         int error;
1325
1326         if ((error = ttywait(tp)) == 0)
1327                 ttyflush(tp, FREAD);
1328         return (error);
1329 }
1330
1331 /*
1332  * Flush tty read and/or write queues, notifying anyone waiting.
1333  */
1334 void
1335 ttyflush(struct tty *tp, int rw)
1336 {
1337         crit_enter();
1338 #if 0
1339 again:
1340 #endif
1341         if (rw & FWRITE) {
1342                 FLUSHQ(&tp->t_outq);
1343                 CLR(tp->t_state, TS_TTSTOP);
1344         }
1345         (*tp->t_stop)(tp, rw);
1346         if (rw & FREAD) {
1347                 FLUSHQ(&tp->t_canq);
1348                 FLUSHQ(&tp->t_rawq);
1349                 CLR(tp->t_lflag, PENDIN);
1350                 tp->t_rocount = 0;
1351                 tp->t_rocol = 0;
1352                 CLR(tp->t_state, TS_LOCAL);
1353                 ttwakeup(tp);
1354                 if (ISSET(tp->t_state, TS_TBLOCK)) {
1355                         if (rw & FWRITE)
1356                                 FLUSHQ(&tp->t_outq);
1357                         ttyunblock(tp);
1358
1359                         /*
1360                          * Don't let leave any state that might clobber the
1361                          * next line discipline (although we should do more
1362                          * to send the START char).  Not clearing the state
1363                          * may have caused the "putc to a clist with no
1364                          * reserved cblocks" panic/kprintf.
1365                          */
1366                         CLR(tp->t_state, TS_TBLOCK);
1367
1368 #if 0 /* forget it, sleeping isn't always safe and we don't know when it is */
1369                         if (ISSET(tp->t_iflag, IXOFF)) {
1370                                 /*
1371                                  * XXX wait a bit in the hope that the stop
1372                                  * character (if any) will go out.  Waiting
1373                                  * isn't good since it allows races.  This
1374                                  * will be fixed when the stop character is
1375                                  * put in a special queue.  Don't bother with
1376                                  * the checks in ttywait() since the timeout
1377                                  * will save us.
1378                                  */
1379                                 SET(tp->t_state, TS_SO_OCOMPLETE);
1380                                 ttysleep(tp, TSA_OCOMPLETE(tp), 0,
1381                                          "ttyfls", hz / 10);
1382                                 /*
1383                                  * Don't try sending the stop character again.
1384                                  */
1385                                 CLR(tp->t_state, TS_TBLOCK);
1386                                 goto again;
1387                         }
1388 #endif
1389                 }
1390         }
1391         if (rw & FWRITE) {
1392                 FLUSHQ(&tp->t_outq);
1393                 ttwwakeup(tp);
1394         }
1395         crit_exit();
1396 }
1397
1398 /*
1399  * Copy in the default termios characters.
1400  */
1401 void
1402 termioschars(struct termios *t)
1403 {
1404
1405         bcopy(ttydefchars, t->c_cc, sizeof t->c_cc);
1406 }
1407
1408 /*
1409  * Old interface.
1410  */
1411 void
1412 ttychars(struct tty *tp)
1413 {
1414
1415         termioschars(&tp->t_termios);
1416 }
1417
1418 /*
1419  * Handle input high water.  Send stop character for the IXOFF case.  Turn
1420  * on our input flow control bit and propagate the changes to the driver.
1421  * XXX the stop character should be put in a special high priority queue.
1422  */
1423 void
1424 ttyblock(struct tty *tp)
1425 {
1426
1427         SET(tp->t_state, TS_TBLOCK);
1428         if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTOP] != _POSIX_VDISABLE &&
1429             clist_putc(tp->t_cc[VSTOP], &tp->t_outq) != 0)
1430                 CLR(tp->t_state, TS_TBLOCK);    /* try again later */
1431         ttstart(tp);
1432 }
1433
1434 /*
1435  * Handle input low water.  Send start character for the IXOFF case.  Turn
1436  * off our input flow control bit and propagate the changes to the driver.
1437  * XXX the start character should be put in a special high priority queue.
1438  */
1439 static void
1440 ttyunblock(struct tty *tp)
1441 {
1442
1443         CLR(tp->t_state, TS_TBLOCK);
1444         if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTART] != _POSIX_VDISABLE &&
1445             clist_putc(tp->t_cc[VSTART], &tp->t_outq) != 0)
1446                 SET(tp->t_state, TS_TBLOCK);    /* try again later */
1447         ttstart(tp);
1448 }
1449
1450 #ifdef notyet
1451 /* Not used by any current (i386) drivers. */
1452 /*
1453  * Restart after an inter-char delay.
1454  */
1455 void
1456 ttrstrt(void *tp_arg)
1457 {
1458         struct tty *tp;
1459
1460         KASSERT(tp_arg != NULL, ("ttrstrt"));
1461
1462         tp = tp_arg;
1463         crit_enter();
1464         CLR(tp->t_state, TS_TIMEOUT);
1465         ttstart(tp);
1466         crit_exit();
1467 }
1468 #endif
1469
1470 int
1471 ttstart(struct tty *tp)
1472 {
1473
1474         if (tp->t_oproc != NULL)        /* XXX: Kludge for pty. */
1475                 (*tp->t_oproc)(tp);
1476         return (0);
1477 }
1478
1479 /*
1480  * "close" a line discipline
1481  */
1482 int
1483 ttylclose(struct tty *tp, int flag)
1484 {
1485
1486         if (flag & FNONBLOCK || ttywflush(tp))
1487                 ttyflush(tp, FREAD | FWRITE);
1488         return (0);
1489 }
1490
1491 /*
1492  * Handle modem control transition on a tty.
1493  * Flag indicates new state of carrier.
1494  * Returns 0 if the line should be turned off, otherwise 1.
1495  */
1496 int
1497 ttymodem(struct tty *tp, int flag)
1498 {
1499
1500         if (ISSET(tp->t_state, TS_CARR_ON) && ISSET(tp->t_cflag, MDMBUF)) {
1501                 /*
1502                  * MDMBUF: do flow control according to carrier flag
1503                  * XXX TS_CAR_OFLOW doesn't do anything yet.  TS_TTSTOP
1504                  * works if IXON and IXANY are clear.
1505                  */
1506                 if (flag) {
1507                         CLR(tp->t_state, TS_CAR_OFLOW);
1508                         CLR(tp->t_state, TS_TTSTOP);
1509                         ttstart(tp);
1510                 } else if (!ISSET(tp->t_state, TS_CAR_OFLOW)) {
1511                         SET(tp->t_state, TS_CAR_OFLOW);
1512                         SET(tp->t_state, TS_TTSTOP);
1513                         (*tp->t_stop)(tp, 0);
1514                 }
1515         } else if (flag == 0) {
1516                 /*
1517                  * Lost carrier.
1518                  */
1519                 CLR(tp->t_state, TS_CARR_ON);
1520                 if (ISSET(tp->t_state, TS_ISOPEN) &&
1521                     !ISSET(tp->t_cflag, CLOCAL)) {
1522                         SET(tp->t_state, TS_ZOMBIE);
1523                         CLR(tp->t_state, TS_CONNECTED);
1524                         if (tp->t_session && tp->t_session->s_leader)
1525                                 ksignal(tp->t_session->s_leader, SIGHUP);
1526                         ttyflush(tp, FREAD | FWRITE);
1527                         return (0);
1528                 }
1529         } else {
1530                 /*
1531                  * Carrier now on.
1532                  */
1533                 SET(tp->t_state, TS_CARR_ON);
1534                 if (!ISSET(tp->t_state, TS_ZOMBIE))
1535                         SET(tp->t_state, TS_CONNECTED);
1536                 wakeup(TSA_CARR_ON(tp));
1537                 ttwakeup(tp);
1538                 ttwwakeup(tp);
1539         }
1540         return (1);
1541 }
1542
1543 /*
1544  * Reinput pending characters after state switch
1545  * call from a critical section.
1546  */
1547 static void
1548 ttypend(struct tty *tp)
1549 {
1550         struct clist tq;
1551         int c;
1552
1553         CLR(tp->t_lflag, PENDIN);
1554         SET(tp->t_state, TS_TYPEN);
1555         /*
1556          * XXX this assumes too much about clist internals.  It may even
1557          * fail if the cblock slush pool is empty.  We can't allocate more
1558          * cblocks here because we are called from an interrupt handler
1559          * and clist_alloc_cblocks() can wait.
1560          */
1561         tq = tp->t_rawq;
1562         bzero(&tp->t_rawq, sizeof tp->t_rawq);
1563         tp->t_rawq.c_cbmax = tq.c_cbmax;
1564         tp->t_rawq.c_cbreserved = tq.c_cbreserved;
1565         while ((c = clist_getc(&tq)) >= 0)
1566                 ttyinput(c, tp);
1567         CLR(tp->t_state, TS_TYPEN);
1568 }
1569
1570 /*
1571  * Process a read call on a tty device.
1572  */
1573 int
1574 ttread(struct tty *tp, struct uio *uio, int flag)
1575 {
1576         struct clist *qp;
1577         int c;
1578         tcflag_t lflag;
1579         cc_t *cc = tp->t_cc;
1580         struct proc *pp;
1581         struct lwp *lp;
1582         int first, error = 0;
1583         int has_stime = 0, last_cc = 0;
1584         long slp = 0;           /* XXX this should be renamed `timo'. */
1585         struct timeval stime;
1586
1587         lp = curthread->td_lwp;
1588
1589 loop:
1590         crit_enter();
1591         lflag = tp->t_lflag;
1592         /*
1593          * take pending input first
1594          */
1595         if (ISSET(lflag, PENDIN)) {
1596                 ttypend(tp);
1597                 splz();         /* reduce latency */
1598                 lflag = tp->t_lflag;    /* XXX ttypend() clobbers it */
1599         }
1600
1601         /*
1602          * Hang process if it's in the background.
1603          */
1604         if ((pp = curproc) && isbackground(pp, tp)) {
1605                 crit_exit();
1606                 if (SIGISMEMBER(pp->p_sigignore, SIGTTIN) ||
1607                     SIGISMEMBER(lp->lwp_sigmask, SIGTTIN) ||
1608                     (pp->p_flag & P_PPWAIT) || pp->p_pgrp->pg_jobc == 0)
1609                         return (EIO);
1610                 pgsignal(pp->p_pgrp, SIGTTIN, 1);
1611                 error = ttysleep(tp, &lbolt, PCATCH, "ttybg2", 0);
1612                 if (error)
1613                         return (error);
1614                 goto loop;
1615         }
1616
1617         if (ISSET(tp->t_state, TS_ZOMBIE)) {
1618                 crit_exit();
1619                 return (0);     /* EOF */
1620         }
1621
1622         /*
1623          * If canonical, use the canonical queue,
1624          * else use the raw queue.
1625          *
1626          * (should get rid of clists...)
1627          */
1628         qp = ISSET(lflag, ICANON) ? &tp->t_canq : &tp->t_rawq;
1629
1630         if (flag & IO_NDELAY) {
1631                 if (qp->c_cc > 0)
1632                         goto read;
1633                 if (!ISSET(lflag, ICANON) && cc[VMIN] == 0) {
1634                         crit_exit();
1635                         return (0);
1636                 }
1637                 crit_exit();
1638                 return (EWOULDBLOCK);
1639         }
1640         if (!ISSET(lflag, ICANON)) {
1641                 int m = cc[VMIN];
1642                 long t = cc[VTIME];
1643                 struct timeval timecopy;
1644
1645                 /*
1646                  * Check each of the four combinations.
1647                  * (m > 0 && t == 0) is the normal read case.
1648                  * It should be fairly efficient, so we check that and its
1649                  * companion case (m == 0 && t == 0) first.
1650                  * For the other two cases, we compute the target sleep time
1651                  * into slp.
1652                  */
1653                 if (t == 0) {
1654                         if (qp->c_cc < m)
1655                                 goto sleep;
1656                         if (qp->c_cc > 0)
1657                                 goto read;
1658
1659                         /* m, t and qp->c_cc are all 0.  0 is enough input. */
1660                         crit_exit();
1661                         return (0);
1662                 }
1663                 t *= 100000;            /* time in us */
1664 #define diff(t1, t2) (((t1).tv_sec - (t2).tv_sec) * 1000000 + \
1665                          ((t1).tv_usec - (t2).tv_usec))
1666                 if (m > 0) {
1667                         if (qp->c_cc <= 0)
1668                                 goto sleep;
1669                         if (qp->c_cc >= m)
1670                                 goto read;
1671                         getmicrotime(&timecopy);
1672                         if (!has_stime) {
1673                                 /* first character, start timer */
1674                                 has_stime = 1;
1675                                 stime = timecopy;
1676                                 slp = t;
1677                         } else if (qp->c_cc > last_cc) {
1678                                 /* got a character, restart timer */
1679                                 stime = timecopy;
1680                                 slp = t;
1681                         } else {
1682                                 /* nothing, check expiration */
1683                                 slp = t - diff(timecopy, stime);
1684                                 if (slp <= 0)
1685                                         goto read;
1686                         }
1687                         last_cc = qp->c_cc;
1688                 } else {        /* m == 0 */
1689                         if (qp->c_cc > 0)
1690                                 goto read;
1691                         getmicrotime(&timecopy);
1692                         if (!has_stime) {
1693                                 has_stime = 1;
1694                                 stime = timecopy;
1695                                 slp = t;
1696                         } else {
1697                                 slp = t - diff(timecopy, stime);
1698                                 if (slp <= 0) {
1699                                         /* Timed out, but 0 is enough input. */
1700                                         crit_exit();
1701                                         return (0);
1702                                 }
1703                         }
1704                 }
1705 #undef diff
1706                 /*
1707                  * Rounding down may make us wake up just short
1708                  * of the target, so we round up.
1709                  * The formula is ceiling(slp * hz/1000000).
1710                  * 32-bit arithmetic is enough for hz < 169.
1711                  * XXX see tvtohz() for how to avoid overflow if hz
1712                  * is large (divide by `tick' and/or arrange to
1713                  * use tvtohz() if hz is large).
1714                  */
1715                 slp = (long) (((u_long)slp * hz) + 999999) / 1000000;
1716                 goto sleep;
1717         }
1718         if (qp->c_cc <= 0) {
1719 sleep:
1720                 /*
1721                  * There is no input, or not enough input and we can block.
1722                  */
1723                 error = ttysleep(tp, TSA_HUP_OR_INPUT(tp), PCATCH,
1724                                  ISSET(tp->t_state, TS_CONNECTED) ?
1725                                  "ttyin" : "ttyhup", (int)slp);
1726                 crit_exit();
1727                 if (error == EWOULDBLOCK)
1728                         error = 0;
1729                 else if (error)
1730                         return (error);
1731                 /*
1732                  * XXX what happens if another process eats some input
1733                  * while we are asleep (not just here)?  It would be
1734                  * safest to detect changes and reset our state variables
1735                  * (has_stime and last_cc).
1736                  */
1737                 slp = 0;
1738                 goto loop;
1739         }
1740 read:
1741         crit_exit();
1742         /*
1743          * Input present, check for input mapping and processing.
1744          */
1745         first = 1;
1746         if (ISSET(lflag, ICANON | ISIG))
1747                 goto slowcase;
1748         for (;;) {
1749                 char ibuf[IBUFSIZ];
1750                 int icc;
1751
1752                 icc = imin(uio->uio_resid, IBUFSIZ);
1753                 icc = q_to_b(qp, ibuf, icc);
1754                 if (icc <= 0) {
1755                         if (first)
1756                                 goto loop;
1757                         break;
1758                 }
1759                 error = uiomove(ibuf, icc, uio);
1760                 /*
1761                  * XXX if there was an error then we should ungetc() the
1762                  * unmoved chars and reduce icc here.
1763                  */
1764                 if (error)
1765                         break;
1766                 if (uio->uio_resid == 0)
1767                         break;
1768                 first = 0;
1769         }
1770         goto out;
1771 slowcase:
1772         for (;;) {
1773                 c = clist_getc(qp);
1774                 if (c < 0) {
1775                         if (first)
1776                                 goto loop;
1777                         break;
1778                 }
1779                 /*
1780                  * delayed suspend (^Y)
1781                  */
1782                 if (CCEQ(cc[VDSUSP], c) &&
1783                     ISSET(lflag, IEXTEN | ISIG) == (IEXTEN | ISIG)) {
1784                         pgsignal(tp->t_pgrp, SIGTSTP, 1);
1785                         if (first) {
1786                                 error = ttysleep(tp, &lbolt, PCATCH,
1787                                                  "ttybg3", 0);
1788                                 if (error)
1789                                         break;
1790                                 goto loop;
1791                         }
1792                         break;
1793                 }
1794                 /*
1795                  * Interpret EOF only in canonical mode.
1796                  */
1797                 if (CCEQ(cc[VEOF], c) && ISSET(lflag, ICANON))
1798                         break;
1799                 /*
1800                  * Give user character.
1801                  */
1802                 error = ureadc(c, uio);
1803                 if (error)
1804                         /* XXX should ungetc(c, qp). */
1805                         break;
1806                 if (uio->uio_resid == 0)
1807                         break;
1808                 /*
1809                  * In canonical mode check for a "break character"
1810                  * marking the end of a "line of input".
1811                  */
1812                 if (ISSET(lflag, ICANON) && TTBREAKC(c, lflag))
1813                         break;
1814                 first = 0;
1815         }
1816
1817 out:
1818         /*
1819          * Look to unblock input now that (presumably)
1820          * the input queue has gone down.
1821          */
1822         crit_enter();
1823         if (ISSET(tp->t_state, TS_TBLOCK) &&
1824             tp->t_rawq.c_cc + tp->t_canq.c_cc <= tp->t_ilowat)
1825                 ttyunblock(tp);
1826         crit_exit();
1827
1828         return (error);
1829 }
1830
1831 /*
1832  * Check the output queue on tp for space for a kernel message (from uprintf
1833  * or tprintf).  Allow some space over the normal hiwater mark so we don't
1834  * lose messages due to normal flow control, but don't let the tty run amok.
1835  * Sleeps here are not interruptible, but we return prematurely if new signals
1836  * arrive.
1837  */
1838 int
1839 ttycheckoutq(struct tty *tp, int wait)
1840 {
1841         struct lwp *lp = curthread->td_lwp;
1842         int hiwat;
1843         sigset_t oldset, newset;
1844
1845         hiwat = tp->t_ohiwat;
1846         SIGEMPTYSET(oldset);
1847         SIGEMPTYSET(newset);
1848         crit_enter();
1849         if (wait)
1850                 oldset = lwp_sigpend(lp);
1851         if (tp->t_outq.c_cc > hiwat + OBUFSIZ + 100) {
1852                 while (tp->t_outq.c_cc > hiwat) {
1853                         ttstart(tp);
1854                         if (tp->t_outq.c_cc <= hiwat)
1855                                 break;
1856                         if (wait)
1857                                 newset = lwp_sigpend(lp);
1858                         if (!wait || SIGSETNEQ(oldset, newset)) {
1859                                 crit_exit();
1860                                 return (0);
1861                         }
1862                         SET(tp->t_state, TS_SO_OLOWAT);
1863                         tsleep(TSA_OLOWAT(tp), 0, "ttoutq", hz);
1864                 }
1865         }
1866         crit_exit();
1867         return (1);
1868 }
1869
1870 /*
1871  * Process a write call on a tty device.
1872  */
1873 int
1874 ttwrite(struct tty *tp, struct uio *uio, int flag)
1875 {
1876         char *cp = NULL;
1877         int cc, ce;
1878         struct proc *pp;
1879         struct lwp *lp;
1880         int i, hiwat, cnt, error;
1881         char obuf[OBUFSIZ];
1882
1883         lp = curthread->td_lwp;
1884         hiwat = tp->t_ohiwat;
1885         cnt = uio->uio_resid;
1886         error = 0;
1887         cc = 0;
1888 loop:
1889         crit_enter();
1890         if (ISSET(tp->t_state, TS_ZOMBIE)) {
1891                 crit_exit();
1892                 if (uio->uio_resid == cnt)
1893                         error = EIO;
1894                 goto out;
1895         }
1896         if (!ISSET(tp->t_state, TS_CONNECTED)) {
1897                 if (flag & IO_NDELAY) {
1898                         crit_exit();
1899                         error = EWOULDBLOCK;
1900                         goto out;
1901                 }
1902                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "ttydcd", 0);
1903                 crit_exit();
1904                 if (error)
1905                         goto out;
1906                 goto loop;
1907         }
1908         crit_exit();
1909
1910         /*
1911          * Hang the process if it's in the background.
1912          */
1913         if ((pp = curproc) && isbackground(pp, tp) &&
1914             ISSET(tp->t_lflag, TOSTOP) && !(pp->p_flag & P_PPWAIT) &&
1915             !SIGISMEMBER(pp->p_sigignore, SIGTTOU) &&
1916             !SIGISMEMBER(lp->lwp_sigmask, SIGTTOU)) {
1917                 if (pp->p_pgrp->pg_jobc == 0) {
1918                         error = EIO;
1919                         goto out;
1920                 }
1921                 pgsignal(pp->p_pgrp, SIGTTOU, 1);
1922                 error = ttysleep(tp, &lbolt, PCATCH, "ttybg4", 0);
1923                 if (error)
1924                         goto out;
1925                 goto loop;
1926         }
1927         /*
1928          * Process the user's data in at most OBUFSIZ chunks.  Perform any
1929          * output translation.  Keep track of high water mark, sleep on
1930          * overflow awaiting device aid in acquiring new space.
1931          */
1932         while (uio->uio_resid > 0 || cc > 0) {
1933                 if (ISSET(tp->t_lflag, FLUSHO)) {
1934                         uio->uio_resid = 0;
1935                         return (0);
1936                 }
1937                 if (tp->t_outq.c_cc > hiwat)
1938                         goto ovhiwat;
1939                 /*
1940                  * Grab a hunk of data from the user, unless we have some
1941                  * leftover from last time.
1942                  */
1943                 if (cc == 0) {
1944                         cc = imin(uio->uio_resid, OBUFSIZ);
1945                         cp = obuf;
1946                         error = uiomove(cp, cc, uio);
1947                         if (error) {
1948                                 cc = 0;
1949                                 break;
1950                         }
1951                 }
1952                 /*
1953                  * If nothing fancy need be done, grab those characters we
1954                  * can handle without any of ttyoutput's processing and
1955                  * just transfer them to the output q.  For those chars
1956                  * which require special processing (as indicated by the
1957                  * bits in char_type), call ttyoutput.  After processing
1958                  * a hunk of data, look for FLUSHO so ^O's will take effect
1959                  * immediately.
1960                  */
1961                 while (cc > 0) {
1962                         if (!ISSET(tp->t_oflag, OPOST))
1963                                 ce = cc;
1964                         else {
1965                                 ce = cc - scanc((u_int)cc, (u_char *)cp,
1966                                                 char_type, CCLASSMASK);
1967                                 /*
1968                                  * If ce is zero, then we're processing
1969                                  * a special character through ttyoutput.
1970                                  */
1971                                 if (ce == 0) {
1972                                         tp->t_rocount = 0;
1973                                         if (ttyoutput(*cp, tp) >= 0) {
1974                                                 /* No Clists, wait a bit. */
1975                                                 ttstart(tp);
1976                                                 if (flag & IO_NDELAY) {
1977                                                         error = EWOULDBLOCK;
1978                                                         goto out;
1979                                                 }
1980                                                 error = ttysleep(tp, &lbolt,
1981                                                                  PCATCH,
1982                                                                  "ttybf1", 0);
1983                                                 if (error)
1984                                                         goto out;
1985                                                 goto loop;
1986                                         }
1987                                         cp++;
1988                                         cc--;
1989                                         if (ISSET(tp->t_lflag, FLUSHO) ||
1990                                             tp->t_outq.c_cc > hiwat)
1991                                                 goto ovhiwat;
1992                                         continue;
1993                                 }
1994                         }
1995                         /*
1996                          * A bunch of normal characters have been found.
1997                          * Transfer them en masse to the output queue and
1998                          * continue processing at the top of the loop.
1999                          * If there are any further characters in this
2000                          * <= OBUFSIZ chunk, the first should be a character
2001                          * requiring special handling by ttyoutput.
2002                          */
2003                         tp->t_rocount = 0;
2004                         i = b_to_q(cp, ce, &tp->t_outq);
2005                         ce -= i;
2006                         tp->t_column += ce;
2007                         cp += ce, cc -= ce, tk_nout += ce;
2008                         tp->t_outcc += ce;
2009                         if (i > 0) {
2010                                 /* No Clists, wait a bit. */
2011                                 ttstart(tp);
2012                                 if (flag & IO_NDELAY) {
2013                                         error = EWOULDBLOCK;
2014                                         goto out;
2015                                 }
2016                                 error = ttysleep(tp, &lbolt, PCATCH,
2017                                                  "ttybf2", 0);
2018                                 if (error)
2019                                         goto out;
2020                                 goto loop;
2021                         }
2022                         if (ISSET(tp->t_lflag, FLUSHO) ||
2023                             tp->t_outq.c_cc > hiwat)
2024                                 break;
2025                 }
2026                 ttstart(tp);
2027         }
2028 out:
2029         /*
2030          * If cc is nonzero, we leave the uio structure inconsistent, as the
2031          * offset and iov pointers have moved forward, but it doesn't matter
2032          * (the call will either return short or restart with a new uio).
2033          */
2034         uio->uio_resid += cc;
2035         return (error);
2036
2037 ovhiwat:
2038         ttstart(tp);
2039         crit_enter();
2040         /*
2041          * This can only occur if FLUSHO is set in t_lflag,
2042          * or if ttstart/oproc is synchronous (or very fast).
2043          */
2044         if (tp->t_outq.c_cc <= hiwat) {
2045                 crit_exit();
2046                 goto loop;
2047         }
2048         if (flag & IO_NDELAY) {
2049                 crit_exit();
2050                 uio->uio_resid += cc;
2051                 return (uio->uio_resid == cnt ? EWOULDBLOCK : 0);
2052         }
2053         SET(tp->t_state, TS_SO_OLOWAT);
2054         error = ttysleep(tp, TSA_OLOWAT(tp), PCATCH, "ttywri", tp->t_timeout);
2055         crit_exit();
2056         if (error == EWOULDBLOCK)
2057                 error = EIO;
2058         if (error)
2059                 goto out;
2060         goto loop;
2061 }
2062
2063 /*
2064  * Rubout one character from the rawq of tp
2065  * as cleanly as possible.
2066  */
2067 static void
2068 ttyrub(int c, struct tty *tp)
2069 {
2070         char *cp;
2071         int savecol;
2072         int tabc;
2073
2074         if (!ISSET(tp->t_lflag, ECHO) || ISSET(tp->t_lflag, EXTPROC))
2075                 return;
2076         CLR(tp->t_lflag, FLUSHO);
2077         if (ISSET(tp->t_lflag, ECHOE)) {
2078                 if (tp->t_rocount == 0) {
2079                         /*
2080                          * Screwed by ttwrite; retype
2081                          */
2082                         ttyretype(tp);
2083                         return;
2084                 }
2085                 if (c == ('\t' | TTY_QUOTE) || c == ('\n' | TTY_QUOTE))
2086                         ttyrubo(tp, 2);
2087                 else {
2088                         CLR(c, ~TTY_CHARMASK);
2089                         switch (CCLASS(c)) {
2090                         case ORDINARY:
2091                                 ttyrubo(tp, 1);
2092                                 break;
2093                         case BACKSPACE:
2094                         case CONTROL:
2095                         case NEWLINE:
2096                         case RETURN:
2097                         case VTAB:
2098                                 if (ISSET(tp->t_lflag, ECHOCTL))
2099                                         ttyrubo(tp, 2);
2100                                 break;
2101                         case TAB:
2102                                 if (tp->t_rocount < tp->t_rawq.c_cc) {
2103                                         ttyretype(tp);
2104                                         return;
2105                                 }
2106                                 crit_enter();
2107                                 savecol = tp->t_column;
2108                                 SET(tp->t_state, TS_CNTTB);
2109                                 SET(tp->t_lflag, FLUSHO);
2110                                 tp->t_column = tp->t_rocol;
2111                                 cp = tp->t_rawq.c_cf;
2112                                 if (cp)
2113                                         tabc = *cp;     /* XXX FIX NEXTC */
2114                                 for (; cp; cp = nextc(&tp->t_rawq, cp, &tabc))
2115                                         ttyecho(tabc, tp);
2116                                 CLR(tp->t_lflag, FLUSHO);
2117                                 CLR(tp->t_state, TS_CNTTB);
2118                                 crit_exit();
2119
2120                                 /* savecol will now be length of the tab. */
2121                                 savecol -= tp->t_column;
2122                                 tp->t_column += savecol;
2123                                 if (savecol > 8)
2124                                         savecol = 8;    /* overflow screw */
2125                                 while (--savecol >= 0)
2126                                         (void)ttyoutput('\b', tp);
2127                                 break;
2128                         default:                        /* XXX */
2129 #define PANICSTR        "ttyrub: would panic c = %d, val = %d\n"
2130                                 (void)kprintf(PANICSTR, c, CCLASS(c));
2131 #ifdef notdef
2132                                 panic(PANICSTR, c, CCLASS(c));
2133 #endif
2134                         }
2135                 }
2136         } else if (ISSET(tp->t_lflag, ECHOPRT)) {
2137                 if (!ISSET(tp->t_state, TS_ERASE)) {
2138                         SET(tp->t_state, TS_ERASE);
2139                         (void)ttyoutput('\\', tp);
2140                 }
2141                 ttyecho(c, tp);
2142         } else {
2143                 ttyecho(tp->t_cc[VERASE], tp);
2144                 /*
2145                  * This code may be executed not only when an ERASE key
2146                  * is pressed, but also when ^U (KILL) or ^W (WERASE) are.
2147                  * So, I didn't think it was worthwhile to pass the extra
2148                  * information (which would need an extra parameter,
2149                  * changing every call) needed to distinguish the ERASE2
2150                  * case from the ERASE.
2151                  */
2152         }
2153         --tp->t_rocount;
2154 }
2155
2156 /*
2157  * Back over cnt characters, erasing them.
2158  */
2159 static void
2160 ttyrubo(struct tty *tp, int cnt)
2161 {
2162
2163         while (cnt-- > 0) {
2164                 (void)ttyoutput('\b', tp);
2165                 (void)ttyoutput(' ', tp);
2166                 (void)ttyoutput('\b', tp);
2167         }
2168 }
2169
2170 /*
2171  * ttyretype --
2172  *      Reprint the rawq line.  Note, it is assumed that c_cc has already
2173  *      been checked.
2174  */
2175 static void
2176 ttyretype(struct tty *tp)
2177 {
2178         char *cp;
2179         int c;
2180
2181         /* Echo the reprint character. */
2182         if (tp->t_cc[VREPRINT] != _POSIX_VDISABLE)
2183                 ttyecho(tp->t_cc[VREPRINT], tp);
2184
2185         (void)ttyoutput('\n', tp);
2186
2187         /*
2188          * XXX
2189          * FIX: NEXTC IS BROKEN - DOESN'T CHECK QUOTE
2190          * BIT OF FIRST CHAR.
2191          */
2192         crit_enter();
2193         for (cp = tp->t_canq.c_cf, c = (cp != NULL ? *cp : 0);
2194             cp != NULL; cp = nextc(&tp->t_canq, cp, &c))
2195                 ttyecho(c, tp);
2196         for (cp = tp->t_rawq.c_cf, c = (cp != NULL ? *cp : 0);
2197             cp != NULL; cp = nextc(&tp->t_rawq, cp, &c))
2198                 ttyecho(c, tp);
2199         CLR(tp->t_state, TS_ERASE);
2200         crit_exit();
2201
2202         tp->t_rocount = tp->t_rawq.c_cc;
2203         tp->t_rocol = 0;
2204 }
2205
2206 /*
2207  * Echo a typed character to the terminal.
2208  */
2209 static void
2210 ttyecho(int c, struct tty *tp)
2211 {
2212
2213         if (!ISSET(tp->t_state, TS_CNTTB))
2214                 CLR(tp->t_lflag, FLUSHO);
2215         if ((!ISSET(tp->t_lflag, ECHO) &&
2216              (c != '\n' || !ISSET(tp->t_lflag, ECHONL))) ||
2217             ISSET(tp->t_lflag, EXTPROC))
2218                 return;
2219         if (ISSET(tp->t_lflag, ECHOCTL) &&
2220             ((ISSET(c, TTY_CHARMASK) <= 037 && c != '\t' && c != '\n') ||
2221             ISSET(c, TTY_CHARMASK) == 0177)) {
2222                 (void)ttyoutput('^', tp);
2223                 CLR(c, ~TTY_CHARMASK);
2224                 if (c == 0177)
2225                         c = '?';
2226                 else
2227                         c += 'A' - 1;
2228         }
2229         (void)ttyoutput(c, tp);
2230 }
2231
2232 /*
2233  * Wake up any readers on a tty.
2234  */
2235 void
2236 ttwakeup(struct tty *tp)
2237 {
2238
2239         if (tp->t_rsel.si_pid != 0)
2240                 selwakeup(&tp->t_rsel);
2241         if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
2242                 pgsigio(tp->t_sigio, SIGIO, (tp->t_session != NULL));
2243         wakeup(TSA_HUP_OR_INPUT(tp));
2244         KNOTE(&tp->t_rsel.si_note, 0);
2245 }
2246
2247 /*
2248  * Wake up any writers on a tty.
2249  */
2250 void
2251 ttwwakeup(struct tty *tp)
2252 {
2253
2254         if (tp->t_wsel.si_pid != 0 && tp->t_outq.c_cc <= tp->t_olowat)
2255                 selwakeup(&tp->t_wsel);
2256         if (ISSET(tp->t_state, TS_ASYNC) && tp->t_sigio != NULL)
2257                 pgsigio(tp->t_sigio, SIGIO, (tp->t_session != NULL));
2258         if (ISSET(tp->t_state, TS_BUSY | TS_SO_OCOMPLETE) ==
2259             TS_SO_OCOMPLETE && tp->t_outq.c_cc == 0) {
2260                 CLR(tp->t_state, TS_SO_OCOMPLETE);
2261                 wakeup(TSA_OCOMPLETE(tp));
2262         }
2263         if (ISSET(tp->t_state, TS_SO_OLOWAT) &&
2264             tp->t_outq.c_cc <= tp->t_olowat) {
2265                 CLR(tp->t_state, TS_SO_OLOWAT);
2266                 wakeup(TSA_OLOWAT(tp));
2267         }
2268         KNOTE(&tp->t_wsel.si_note, 0);
2269 }
2270
2271 /*
2272  * Look up a code for a specified speed in a conversion table;
2273  * used by drivers to map software speed values to hardware parameters.
2274  */
2275 int
2276 ttspeedtab(int speed, struct speedtab *table)
2277 {
2278
2279         for ( ; table->sp_speed != -1; table++)
2280                 if (table->sp_speed == speed)
2281                         return (table->sp_code);
2282         return (-1);
2283 }
2284
2285 /*
2286  * Set input and output watermarks and buffer sizes.  For input, the
2287  * high watermark is about one second's worth of input above empty, the
2288  * low watermark is slightly below high water, and the buffer size is a
2289  * driver-dependent amount above high water.  For output, the watermarks
2290  * are near the ends of the buffer, with about 1 second's worth of input
2291  * between them.  All this only applies to the standard line discipline.
2292  */
2293 void
2294 ttsetwater(struct tty *tp)
2295 {
2296         int cps, ttmaxhiwat, x;
2297
2298         /* Input. */
2299         clist_alloc_cblocks(&tp->t_canq, TTYHOG, 512);
2300         switch (tp->t_ispeedwat) {
2301         case (speed_t)-1:
2302                 cps = tp->t_ispeed / 10;
2303                 break;
2304         case 0:
2305                 /*
2306                  * This case is for old drivers that don't know about
2307                  * t_ispeedwat.  Arrange for them to get the old buffer
2308                  * sizes and watermarks.
2309                  */
2310                 cps = TTYHOG - 2 * 256;
2311                 tp->t_ififosize = 2 * 2048;
2312                 break;
2313         default:
2314                 cps = tp->t_ispeedwat / 10;
2315                 break;
2316         }
2317         tp->t_ihiwat = cps;
2318         tp->t_ilowat = 7 * cps / 8;
2319         x = cps + tp->t_ififosize;
2320         clist_alloc_cblocks(&tp->t_rawq, x, x);
2321
2322         /* Output. */
2323         switch (tp->t_ospeedwat) {
2324         case (speed_t)-1:
2325                 cps = tp->t_ospeed / 10;
2326                 ttmaxhiwat = 2 * TTMAXHIWAT;
2327                 break;
2328         case 0:
2329                 cps = tp->t_ospeed / 10;
2330                 ttmaxhiwat = TTMAXHIWAT;
2331                 break;
2332         default:
2333                 cps = tp->t_ospeedwat / 10;
2334                 ttmaxhiwat = 8 * TTMAXHIWAT;
2335                 break;
2336         }
2337 #define CLAMP(x, h, l)  ((x) > h ? h : ((x) < l) ? l : (x))
2338         tp->t_olowat = x = CLAMP(cps / 2, TTMAXLOWAT, TTMINLOWAT);
2339         x += cps;
2340         x = CLAMP(x, ttmaxhiwat, TTMINHIWAT);   /* XXX clamps are too magic */
2341         tp->t_ohiwat = roundup(x, CBSIZE);      /* XXX for compat */
2342         x = imax(tp->t_ohiwat, TTMAXHIWAT);     /* XXX for compat/safety */
2343         x += OBUFSIZ + 100;
2344         clist_alloc_cblocks(&tp->t_outq, x, x);
2345 #undef  CLAMP
2346 }
2347
2348 /*
2349  * Report on state of foreground process group.
2350  */
2351 void
2352 ttyinfo(struct tty *tp)
2353 {
2354         struct proc *p, *pick;
2355         struct lwp *lp;
2356         struct rusage ru;
2357         int tmp;
2358
2359         if (ttycheckoutq(tp,0) == 0)
2360                 return;
2361
2362         /*
2363          * We always print the load average, then figure out what else to
2364          * print based on the state of the current process group.
2365          */
2366         tmp = (averunnable.ldavg[0] * 100 + FSCALE / 2) >> FSHIFT;
2367         ttyprintf(tp, "load: %d.%02d ", tmp / 100, tmp % 100);
2368
2369         if (tp->t_session == NULL) {
2370                 ttyprintf(tp, "not a controlling terminal\n");
2371         } else if (tp->t_pgrp == NULL) {
2372                 ttyprintf(tp, "no foreground process group\n");
2373         } else if ((p = LIST_FIRST(&tp->t_pgrp->pg_members)) == 0) {
2374                 ttyprintf(tp, "empty foreground process group\n");
2375         } else {
2376                 /*
2377                  * Pick an interesting process.  Note that certain elements,
2378                  * in particular the wmesg, require a critical section for
2379                  * safe access (YYY and we are still not MP safe).
2380                  *
2381                  * NOTE: lwp_wmesg is lwp_thread->td_wmesg.
2382                  */
2383                 char buf[64];
2384                 const char *str;
2385                 long vmsz;
2386                 int pctcpu;
2387
2388                 crit_enter();
2389
2390                 /* XXX lwp should compare lwps */
2391
2392                 for (pick = NULL; p != 0; p = LIST_NEXT(p, p_pglist)) {
2393                         if (proc_compare(pick, p))
2394                                 pick = p;
2395                 }
2396
2397                 /* XXX lwp */
2398                 lp = FIRST_LWP_IN_PROC(pick);
2399                 if (lp == NULL) {
2400                         ttyprintf(tp, "foreground process without lwp\n");
2401                         tp->t_rocount = 0;
2402                         crit_exit();
2403                         return;
2404                 }
2405
2406                 /*
2407                  * Figure out what wait/process-state message, and command
2408                  * buffer to present
2409                  */
2410                 /*
2411                  * XXX lwp This is a horrible mixture.  We need to rework this
2412                  * as soon as lwps have their own runnable status.
2413                  */
2414                 if (pick->p_flag & P_WEXIT)
2415                         str = "exiting";
2416                 else if (lp->lwp_stat == LSRUN)
2417                         str = "running";
2418                 else if (pick->p_stat == SIDL)
2419                         str = "spawning";
2420                 else if (lp->lwp_wmesg) /* lwp_thread must not be NULL */
2421                         str = lp->lwp_wmesg;
2422                 else
2423                         str = "iowait";
2424
2425                 ksnprintf(buf, sizeof(buf), "cmd: %s %d [%s]",
2426                         pick->p_comm, pick->p_pid, str);
2427
2428                 /*
2429                  * Calculate cpu usage, percent cpu, and cmsz.  Note that
2430                  * 'pick' becomes invalid the moment we exit the critical
2431                  * section.
2432                  */
2433                 if (lp->lwp_thread && (pick->p_flag & P_SWAPPEDOUT) == 0)
2434                         calcru_proc(pick, &ru);
2435
2436                 pctcpu = (lp->lwp_pctcpu * 10000 + FSCALE / 2) >> FSHIFT;
2437
2438                 if (pick->p_stat == SIDL || pick->p_stat == SZOMB)
2439                     vmsz = 0;
2440                 else
2441                     vmsz = pgtok(vmspace_resident_count(pick->p_vmspace));
2442
2443                 crit_exit();
2444
2445                 /*
2446                  * Dump the output
2447                  */
2448                 ttyprintf(tp, " %s ", buf);
2449                 ttyprintf(tp, "%ld.%02ldu ",
2450                         ru.ru_utime.tv_sec, ru.ru_utime.tv_usec / 10000);
2451                 ttyprintf(tp, "%ld.%02lds ",
2452                         ru.ru_stime.tv_sec, ru.ru_stime.tv_usec / 10000);
2453                 ttyprintf(tp, "%d%% %ldk\n", pctcpu / 100, vmsz);
2454         }
2455         tp->t_rocount = 0;      /* so pending input will be retyped if BS */
2456 }
2457
2458 /*
2459  * Returns 1 if p2 is "better" than p1
2460  *
2461  * The algorithm for picking the "interesting" process is thus:
2462  *
2463  *      1) Only foreground processes are eligible - implied.
2464  *      2) Runnable processes are favored over anything else.  The runner
2465  *         with the highest cpu utilization is picked (p_cpticks).  Ties are
2466  *         broken by picking the highest pid.
2467  *      3) The sleeper with the shortest sleep time is next.  With ties,
2468  *         we pick out just "short-term" sleepers (LWP_SINTR == 0).
2469  *      4) Further ties are broken by picking the highest pid.
2470  */
2471 #define ISRUN(lp)       ((lp)->lwp_stat == LSRUN)
2472 #define TESTAB(a, b)    ((a)<<1 | (b))
2473 #define ONLYA   2
2474 #define ONLYB   1
2475 #define BOTH    3
2476
2477 static int
2478 proc_compare(struct proc *p1, struct proc *p2)
2479 {
2480         struct lwp *lp1, *lp2;
2481         if (p1 == NULL)
2482                 return (1);
2483
2484         /*
2485          * weed out zombies
2486          */
2487         switch (TESTAB(p1->p_stat == SZOMB, p2->p_stat == SZOMB)) {
2488         case ONLYA:
2489                 return (1);
2490         case ONLYB:
2491                 return (0);
2492         case BOTH:
2493                 return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
2494         }
2495
2496         /* XXX lwp */
2497         lp1 = FIRST_LWP_IN_PROC(p1);
2498         lp2 = FIRST_LWP_IN_PROC(p2);
2499
2500         /*
2501          * see if at least one of them is runnable
2502          */
2503         switch (TESTAB(ISRUN(lp1), ISRUN(lp2))) {
2504         case ONLYA:
2505                 return (0);
2506         case ONLYB:
2507                 return (1);
2508         case BOTH:
2509                 /*
2510                  * tie - favor one with highest recent cpu utilization
2511                  */
2512                 if (lp2->lwp_cpticks > lp1->lwp_cpticks)
2513                         return (1);
2514                 if (lp1->lwp_cpticks > lp2->lwp_cpticks)
2515                         return (0);
2516                 return (p2->p_pid > p1->p_pid); /* tie - return highest pid */
2517         }
2518         /*
2519          * pick the one with the smallest sleep time
2520          */
2521         if (lp2->lwp_slptime > lp1->lwp_slptime)
2522                 return (0);
2523         if (lp1->lwp_slptime > lp2->lwp_slptime)
2524                 return (1);
2525         /*
2526          * favor one sleeping in a non-interruptible sleep
2527          */
2528         if (lp1->lwp_flag & LWP_SINTR && (lp2->lwp_flag & LWP_SINTR) == 0)
2529                 return (1);
2530         if (lp2->lwp_flag & LWP_SINTR && (lp1->lwp_flag & LWP_SINTR) == 0)
2531                 return (0);
2532         return (p2->p_pid > p1->p_pid);         /* tie - return highest pid */
2533 }
2534
2535 /*
2536  * Output char to tty; console putchar style.
2537  */
2538 int
2539 tputchar(int c, struct tty *tp)
2540 {
2541         crit_enter();
2542         if (!ISSET(tp->t_state, TS_CONNECTED)) {
2543                 crit_exit();
2544                 return (-1);
2545         }
2546         if (c == '\n')
2547                 (void)ttyoutput('\r', tp);
2548         (void)ttyoutput(c, tp);
2549         ttstart(tp);
2550         crit_exit();
2551         return (0);
2552 }
2553
2554 /*
2555  * Sleep on chan, returning ERESTART if tty changed while we napped and
2556  * returning any errors (e.g. EINTR/EWOULDBLOCK) reported by tsleep.  If
2557  * the tty is revoked, restarting a pending call will redo validation done
2558  * at the start of the call.
2559  */
2560 int
2561 ttysleep(struct tty *tp, void *chan, int slpflags, char *wmesg, int timo)
2562 {
2563         int error;
2564         int gen;
2565
2566         gen = tp->t_gen;
2567         error = tsleep(chan, slpflags, wmesg, timo);
2568         if (error)
2569                 return (error);
2570         return (tp->t_gen == gen ? 0 : ERESTART);
2571 }
2572
2573 /*
2574  * Allocate a tty struct.  Clists in the struct will be allocated by
2575  * ttyopen().
2576  */
2577 struct tty *
2578 ttymalloc(struct tty *tp)
2579 {
2580
2581         if (tp)
2582                 return(tp);
2583         tp = kmalloc(sizeof *tp, M_TTYS, M_WAITOK|M_ZERO);
2584         ttyregister(tp);
2585         return (tp);
2586 }
2587
2588 #if 0
2589 /*
2590  * Free a tty struct.  Clists in the struct should have been freed by
2591  * ttyclose().
2592  *
2593  * XXX not yet usable: since we support a half-closed state and do not
2594  * ref count the tty reference from the session, it is possible for a
2595  * session to hold a ref on the tty.  See TTY_DO_FULL_CLOSE.
2596  */
2597 void
2598 ttyfree(struct tty *tp)
2599 {
2600         kfree(tp, M_TTYS);
2601 }
2602 #endif /* 0 */
2603
2604 void
2605 ttyregister(struct tty *tp)
2606 {
2607         SLIST_INSERT_HEAD(&tty_list, tp, t_list);
2608 }
2609
2610 static int
2611 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
2612 {
2613         int error;
2614         struct tty *tp, t;
2615         SLIST_FOREACH(tp, &tty_list, t_list) {
2616                 t = *tp;
2617                 if (t.t_dev)
2618                         t.t_dev = (cdev_t)dev2udev(t.t_dev);
2619                 error = SYSCTL_OUT(req, (caddr_t)&t, sizeof(t));
2620                 if (error)
2621                         return (error);
2622         }
2623         return (0);
2624 }
2625
2626 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD,
2627         0, 0, sysctl_kern_ttys, "S,tty", "All struct ttys");
2628
2629 void
2630 nottystop(struct tty *tp, int rw)
2631 {
2632
2633         return;
2634 }
2635
2636 int
2637 ttyread(struct dev_read_args *ap)
2638 {
2639         struct tty *tp;
2640
2641         tp = ap->a_head.a_dev->si_tty;
2642         if (tp == NULL)
2643                 return (ENODEV);
2644         return ((*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag));
2645 }
2646
2647 int
2648 ttywrite(struct dev_write_args *ap)
2649 {
2650         struct tty *tp;
2651
2652         tp = ap->a_head.a_dev->si_tty;
2653         if (tp == NULL)
2654                 return (ENODEV);
2655         return ((*linesw[tp->t_line].l_write)(tp, ap->a_uio, ap->a_ioflag));
2656 }