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