sys/kern/tty.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
   5  * All rights reserved.
   6  *
   7  * Portions of this software were developed under sponsorship from Snow
   8  * B.V., the Netherlands.
   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  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include "opt_capsicum.h"
  36 #include "opt_compat.h"
  37
  38 #include <sys/param.h>
  39 #include <sys/capsicum.h>
  40 #include <sys/conf.h>
  41 #include <sys/cons.h>
  42 #include <sys/fcntl.h>
  43 #include <sys/file.h>
  44 #include <sys/filedesc.h>
  45 #include <sys/filio.h>
  46 #ifdef COMPAT_43TTY
  47 #include <sys/ioctl_compat.h>
  48 #endif /* COMPAT_43TTY */
  49 #include <sys/kernel.h>
  50 #include <sys/limits.h>
  51 #include <sys/malloc.h>
  52 #include <sys/mount.h>
  53 #include <sys/poll.h>
  54 #include <sys/priv.h>
  55 #include <sys/proc.h>
  56 #include <sys/serial.h>
  57 #include <sys/signal.h>
  58 #include <sys/stat.h>
  59 #include <sys/sx.h>
  60 #include <sys/sysctl.h>
  61 #include <sys/systm.h>
  62 #include <sys/tty.h>
  63 #include <sys/ttycom.h>
  64 #define TTYDEFCHARS
  65 #include <sys/ttydefaults.h>
  66 #undef TTYDEFCHARS
  67 #include <sys/ucred.h>
  68 #include <sys/vnode.h>
  69
  70 #include <machine/stdarg.h>
  71
  72 static MALLOC_DEFINE(M_TTY, "tty", "tty device");
  73
  74 static void tty_rel_free(struct tty *tp);
  75
  76 static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
  77 static struct sx tty_list_sx;
  78 SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
  79 static unsigned int tty_list_count = 0;
  80
  81 /* Character device of /dev/console. */
  82 static struct cdev      *dev_console;
  83 static const char       *dev_console_filename;
  84
  85 /*
  86  * Flags that are supported and stored by this implementation.
  87  */
  88 #define TTYSUP_IFLAG    (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|\
  89                         INLCR|IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL)
  90 #define TTYSUP_OFLAG    (OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
  91 #define TTYSUP_LFLAG    (ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
  92                         ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
  93                         FLUSHO|NOKERNINFO|NOFLSH)
  94 #define TTYSUP_CFLAG    (CIGNORE|CSIZE|CSTOPB|CREAD|PARENB|PARODD|\
  95                         HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
  96                         CDSR_OFLOW|CCAR_OFLOW)
  97
  98 #define TTY_CALLOUT(tp,d) (dev2unit(d) & TTYUNIT_CALLOUT)
  99
 100 static int  tty_drainwait = 5 * 60;
 101 SYSCTL_INT(_kern, OID_AUTO, tty_drainwait, CTLFLAG_RWTUN,
 102     &tty_drainwait, 0, "Default output drain timeout in seconds");
 103
 104 /*
 105  * Set TTY buffer sizes.
 106  */
 107
 108 #define TTYBUF_MAX      65536
 109
 110 /*
 111  * Allocate buffer space if necessary, and set low watermarks, based on speed.
 112  * Note that the ttyxxxq_setsize() functions may drop and then reacquire the tty
 113  * lock during memory allocation.  They will return ENXIO if the tty disappears
 114  * while unlocked.
 115  */
 116 static int
 117 tty_watermarks(struct tty *tp)
 118 {
 119         size_t bs = 0;
 120         int error;
 121
 122         /* Provide an input buffer for 2 seconds of data. */
 123         if (tp->t_termios.c_cflag & CREAD)
 124                 bs = MIN(tp->t_termios.c_ispeed / 5, TTYBUF_MAX);
 125         error = ttyinq_setsize(&tp->t_inq, tp, bs);
 126         if (error != 0)
 127                 return (error);
 128
 129         /* Set low watermark at 10% (when 90% is available). */
 130         tp->t_inlow = (ttyinq_getallocatedsize(&tp->t_inq) * 9) / 10;
 131
 132         /* Provide an output buffer for 2 seconds of data. */
 133         bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
 134         error = ttyoutq_setsize(&tp->t_outq, tp, bs);
 135         if (error != 0)
 136                 return (error);
 137
 138         /* Set low watermark at 10% (when 90% is available). */
 139         tp->t_outlow = (ttyoutq_getallocatedsize(&tp->t_outq) * 9) / 10;
 140
 141         return (0);
 142 }
 143
 144 static int
 145 tty_drain(struct tty *tp, int leaving)
 146 {
 147         sbintime_t timeout_at;
 148         size_t bytes;
 149         int error;
 150
 151         if (ttyhook_hashook(tp, getc_inject))
 152                 /* buffer is inaccessible */
 153                 return (0);
 154
 155         /*
 156          * For close(), use the recent historic timeout of "1 second without
 157          * making progress".  For tcdrain(), use t_drainwait as the timeout,
 158          * with zero meaning "no timeout" which gives POSIX behavior.
 159          */
 160         if (leaving)
 161                 timeout_at = getsbinuptime() + SBT_1S;
 162         else if (tp->t_drainwait != 0)
 163                 timeout_at = getsbinuptime() + SBT_1S * tp->t_drainwait;
 164         else
 165                 timeout_at = 0;
 166
 167         /*
 168          * Poll the output buffer and the hardware for completion, at 10 Hz.
 169          * Polling is required for devices which are not able to signal an
 170          * interrupt when the transmitter becomes idle (most USB serial devs).
 171          * The unusual structure of this loop ensures we check for busy one more
 172          * time after tty_timedwait() returns EWOULDBLOCK, so that success has
 173          * higher priority than timeout if the IO completed in the last 100mS.
 174          */
 175         error = 0;
 176         bytes = ttyoutq_bytesused(&tp->t_outq);
 177         for (;;) {
 178                 if (ttyoutq_bytesused(&tp->t_outq) == 0 && !ttydevsw_busy(tp))
 179                         return (0);
 180                 if (error != 0)
 181                         return (error);
 182                 ttydevsw_outwakeup(tp);
 183                 error = tty_timedwait(tp, &tp->t_outwait, hz / 10);
 184                 if (error != 0 && error != EWOULDBLOCK)
 185                         return (error);
 186                 else if (timeout_at == 0 || getsbinuptime() < timeout_at)
 187                         error = 0;
 188                 else if (leaving && ttyoutq_bytesused(&tp->t_outq) < bytes) {
 189                         /* In close, making progress, grant an extra second. */
 190                         error = 0;
 191                         timeout_at += SBT_1S;
 192                         bytes = ttyoutq_bytesused(&tp->t_outq);
 193                 }
 194         }
 195 }
 196
 197 /*
 198  * Though ttydev_enter() and ttydev_leave() seem to be related, they
 199  * don't have to be used together. ttydev_enter() is used by the cdev
 200  * operations to prevent an actual operation from being processed when
 201  * the TTY has been abandoned. ttydev_leave() is used by ttydev_open()
 202  * and ttydev_close() to determine whether per-TTY data should be
 203  * deallocated.
 204  */
 205
 206 static __inline int
 207 ttydev_enter(struct tty *tp)
 208 {
 209
 210         tty_lock(tp);
 211
 212         if (tty_gone(tp) || !tty_opened(tp)) {
 213                 /* Device is already gone. */
 214                 tty_unlock(tp);
 215                 return (ENXIO);
 216         }
 217
 218         return (0);
 219 }
 220
 221 static void
 222 ttydev_leave(struct tty *tp)
 223 {
 224
 225         tty_lock_assert(tp, MA_OWNED);
 226
 227         if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
 228                 /* Device is still opened somewhere. */
 229                 tty_unlock(tp);
 230                 return;
 231         }
 232
 233         tp->t_flags |= TF_OPENCLOSE;
 234
 235         /* Stop asynchronous I/O. */
 236         funsetown(&tp->t_sigio);
 237
 238         /* Remove console TTY. */
 239         if (constty == tp)
 240                 constty_clear();
 241
 242         /* Drain any output. */
 243         if (!tty_gone(tp))
 244                 tty_drain(tp, 1);
 245
 246         ttydisc_close(tp);
 247
 248         /* Free i/o queues now since they might be large. */
 249         ttyinq_free(&tp->t_inq);
 250         tp->t_inlow = 0;
 251         ttyoutq_free(&tp->t_outq);
 252         tp->t_outlow = 0;
 253
 254         knlist_clear(&tp->t_inpoll.si_note, 1);
 255         knlist_clear(&tp->t_outpoll.si_note, 1);
 256
 257         if (!tty_gone(tp))
 258                 ttydevsw_close(tp);
 259
 260         tp->t_flags &= ~TF_OPENCLOSE;
 261         cv_broadcast(&tp->t_dcdwait);
 262         tty_rel_free(tp);
 263 }
 264
 265 /*
 266  * Operations that are exposed through the character device in /dev.
 267  */
 268 static int
 269 ttydev_open(struct cdev *dev, int oflags, int devtype __unused,
 270     struct thread *td)
 271 {
 272         struct tty *tp;
 273         int error;
 274
 275         tp = dev->si_drv1;
 276         error = 0;
 277         tty_lock(tp);
 278         if (tty_gone(tp)) {
 279                 /* Device is already gone. */
 280                 tty_unlock(tp);
 281                 return (ENXIO);
 282         }
 283
 284         /*
 285          * Block when other processes are currently opening or closing
 286          * the TTY.
 287          */
 288         while (tp->t_flags & TF_OPENCLOSE) {
 289                 error = tty_wait(tp, &tp->t_dcdwait);
 290                 if (error != 0) {
 291                         tty_unlock(tp);
 292                         return (error);
 293                 }
 294         }
 295         tp->t_flags |= TF_OPENCLOSE;
 296
 297         /*
 298          * Make sure the "tty" and "cua" device cannot be opened at the
 299          * same time.  The console is a "tty" device.
 300          */
 301         if (TTY_CALLOUT(tp, dev)) {
 302                 if (tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) {
 303                         error = EBUSY;
 304                         goto done;
 305                 }
 306         } else {
 307                 if (tp->t_flags & TF_OPENED_OUT) {
 308                         error = EBUSY;
 309                         goto done;
 310                 }
 311         }
 312
 313         if (tp->t_flags & TF_EXCLUDE && priv_check(td, PRIV_TTY_EXCLUSIVE)) {
 314                 error = EBUSY;
 315                 goto done;
 316         }
 317
 318         if (!tty_opened(tp)) {
 319                 /* Set proper termios flags. */
 320                 if (TTY_CALLOUT(tp, dev))
 321                         tp->t_termios = tp->t_termios_init_out;
 322                 else
 323                         tp->t_termios = tp->t_termios_init_in;
 324                 ttydevsw_param(tp, &tp->t_termios);
 325                 /* Prevent modem control on callout devices and /dev/console. */
 326                 if (TTY_CALLOUT(tp, dev) || dev == dev_console)
 327                         tp->t_termios.c_cflag |= CLOCAL;
 328
 329                 ttydevsw_modem(tp, SER_DTR|SER_RTS, 0);
 330
 331                 error = ttydevsw_open(tp);
 332                 if (error != 0)
 333                         goto done;
 334
 335                 ttydisc_open(tp);
 336                 error = tty_watermarks(tp);
 337                 if (error != 0)
 338                         goto done;
 339         }
 340
 341         /* Wait for Carrier Detect. */
 342         if ((oflags & O_NONBLOCK) == 0 &&
 343             (tp->t_termios.c_cflag & CLOCAL) == 0) {
 344                 while ((ttydevsw_modem(tp, 0, 0) & SER_DCD) == 0) {
 345                         error = tty_wait(tp, &tp->t_dcdwait);
 346                         if (error != 0)
 347                                 goto done;
 348                 }
 349         }
 350
 351         if (dev == dev_console)
 352                 tp->t_flags |= TF_OPENED_CONS;
 353         else if (TTY_CALLOUT(tp, dev))
 354                 tp->t_flags |= TF_OPENED_OUT;
 355         else
 356                 tp->t_flags |= TF_OPENED_IN;
 357         MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
 358             (tp->t_flags & TF_OPENED_OUT) == 0);
 359
 360 done:   tp->t_flags &= ~TF_OPENCLOSE;
 361         cv_broadcast(&tp->t_dcdwait);
 362         ttydev_leave(tp);
 363
 364         return (error);
 365 }
 366
 367 static int
 368 ttydev_close(struct cdev *dev, int fflag, int devtype __unused,
 369     struct thread *td __unused)
 370 {
 371         struct tty *tp = dev->si_drv1;
 372
 373         tty_lock(tp);
 374
 375         /*
 376          * Don't actually close the device if it is being used as the
 377          * console.
 378          */
 379         MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
 380             (tp->t_flags & TF_OPENED_OUT) == 0);
 381         if (dev == dev_console)
 382                 tp->t_flags &= ~TF_OPENED_CONS;
 383         else
 384                 tp->t_flags &= ~(TF_OPENED_IN|TF_OPENED_OUT);
 385
 386         if (tp->t_flags & TF_OPENED) {
 387                 tty_unlock(tp);
 388                 return (0);
 389         }
 390
 391         /* If revoking, flush output now to avoid draining it later. */
 392         if (fflag & FREVOKE)
 393                 tty_flush(tp, FWRITE);
 394
 395         tp->t_flags &= ~TF_EXCLUDE;
 396
 397         /* Properly wake up threads that are stuck - revoke(). */
 398         tp->t_revokecnt++;
 399         tty_wakeup(tp, FREAD|FWRITE);
 400         cv_broadcast(&tp->t_bgwait);
 401         cv_broadcast(&tp->t_dcdwait);
 402
 403         ttydev_leave(tp);
 404
 405         return (0);
 406 }
 407
 408 static __inline int
 409 tty_is_ctty(struct tty *tp, struct proc *p)
 410 {
 411
 412         tty_lock_assert(tp, MA_OWNED);
 413
 414         return (p->p_session == tp->t_session && p->p_flag & P_CONTROLT);
 415 }
 416
 417 int
 418 tty_wait_background(struct tty *tp, struct thread *td, int sig)
 419 {
 420         struct proc *p = td->td_proc;
 421         struct pgrp *pg;
 422         ksiginfo_t ksi;
 423         int error;
 424
 425         MPASS(sig == SIGTTIN || sig == SIGTTOU);
 426         tty_lock_assert(tp, MA_OWNED);
 427
 428         for (;;) {
 429                 PROC_LOCK(p);
 430                 /*
 431                  * The process should only sleep, when:
 432                  * - This terminal is the controlling terminal
 433                  * - Its process group is not the foreground process
 434                  *   group
 435                  * - The parent process isn't waiting for the child to
 436                  *   exit
 437                  * - the signal to send to the process isn't masked
 438                  */
 439                 if (!tty_is_ctty(tp, p) || p->p_pgrp == tp->t_pgrp) {
 440                         /* Allow the action to happen. */
 441                         PROC_UNLOCK(p);
 442                         return (0);
 443                 }
 444
 445                 if (SIGISMEMBER(p->p_sigacts->ps_sigignore, sig) ||
 446                     SIGISMEMBER(td->td_sigmask, sig)) {
 447                         /* Only allow them in write()/ioctl(). */
 448                         PROC_UNLOCK(p);
 449                         return (sig == SIGTTOU ? 0 : EIO);
 450                 }
 451
 452                 pg = p->p_pgrp;
 453                 if (p->p_flag & P_PPWAIT || pg->pg_jobc == 0) {
 454                         /* Don't allow the action to happen. */
 455                         PROC_UNLOCK(p);
 456                         return (EIO);
 457                 }
 458                 PROC_UNLOCK(p);
 459
 460                 /*
 461                  * Send the signal and sleep until we're the new
 462                  * foreground process group.
 463                  */
 464                 if (sig != 0) {
 465                         ksiginfo_init(&ksi);
 466                         ksi.ksi_code = SI_KERNEL;
 467                         ksi.ksi_signo = sig;
 468                         sig = 0;
 469                 }
 470                 PGRP_LOCK(pg);
 471                 pgsignal(pg, ksi.ksi_signo, 1, &ksi);
 472                 PGRP_UNLOCK(pg);
 473
 474                 error = tty_wait(tp, &tp->t_bgwait);
 475                 if (error)
 476                         return (error);
 477         }
 478 }
 479
 480 static int
 481 ttydev_read(struct cdev *dev, struct uio *uio, int ioflag)
 482 {
 483         struct tty *tp = dev->si_drv1;
 484         int error;
 485
 486         error = ttydev_enter(tp);
 487         if (error)
 488                 goto done;
 489         error = ttydisc_read(tp, uio, ioflag);
 490         tty_unlock(tp);
 491
 492         /*
 493          * The read() call should not throw an error when the device is
 494          * being destroyed. Silently convert it to an EOF.
 495          */
 496 done:   if (error == ENXIO)
 497                 error = 0;
 498         return (error);
 499 }
 500
 501 static int
 502 ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
 503 {
 504         struct tty *tp = dev->si_drv1;
 505         int error;
 506
 507         error = ttydev_enter(tp);
 508         if (error)
 509                 return (error);
 510
 511         if (tp->t_termios.c_lflag & TOSTOP) {
 512                 error = tty_wait_background(tp, curthread, SIGTTOU);
 513                 if (error)
 514                         goto done;
 515         }
 516
 517         if (ioflag & IO_NDELAY && tp->t_flags & TF_BUSY_OUT) {
 518                 /* Allow non-blocking writes to bypass serialization. */
 519                 error = ttydisc_write(tp, uio, ioflag);
 520         } else {
 521                 /* Serialize write() calls. */
 522                 while (tp->t_flags & TF_BUSY_OUT) {
 523                         error = tty_wait(tp, &tp->t_outserwait);
 524                         if (error)
 525                                 goto done;
 526                 }
 527
 528                 tp->t_flags |= TF_BUSY_OUT;
 529                 error = ttydisc_write(tp, uio, ioflag);
 530                 tp->t_flags &= ~TF_BUSY_OUT;
 531                 cv_signal(&tp->t_outserwait);
 532         }
 533
 534 done:   tty_unlock(tp);
 535         return (error);
 536 }
 537
 538 static int
 539 ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
 540     struct thread *td)
 541 {
 542         struct tty *tp = dev->si_drv1;
 543         int error;
 544
 545         error = ttydev_enter(tp);
 546         if (error)
 547                 return (error);
 548
 549         switch (cmd) {
 550         case TIOCCBRK:
 551         case TIOCCONS:
 552         case TIOCDRAIN:
 553         case TIOCEXCL:
 554         case TIOCFLUSH:
 555         case TIOCNXCL:
 556         case TIOCSBRK:
 557         case TIOCSCTTY:
 558         case TIOCSETA:
 559         case TIOCSETAF:
 560         case TIOCSETAW:
 561         case TIOCSPGRP:
 562         case TIOCSTART:
 563         case TIOCSTAT:
 564         case TIOCSTI:
 565         case TIOCSTOP:
 566         case TIOCSWINSZ:
 567 #if 0
 568         case TIOCSDRAINWAIT:
 569         case TIOCSETD:
 570 #endif
 571 #ifdef COMPAT_43TTY
 572         case  TIOCLBIC:
 573         case  TIOCLBIS:
 574         case  TIOCLSET:
 575         case  TIOCSETC:
 576         case OTIOCSETD:
 577         case  TIOCSETN:
 578         case  TIOCSETP:
 579         case  TIOCSLTC:
 580 #endif /* COMPAT_43TTY */
 581                 /*
 582                  * If the ioctl() causes the TTY to be modified, let it
 583                  * wait in the background.
 584                  */
 585                 error = tty_wait_background(tp, curthread, SIGTTOU);
 586                 if (error)
 587                         goto done;
 588         }
 589
 590         if (cmd == TIOCSETA || cmd == TIOCSETAW || cmd == TIOCSETAF) {
 591                 struct termios *old = &tp->t_termios;
 592                 struct termios *new = (struct termios *)data;
 593                 struct termios *lock = TTY_CALLOUT(tp, dev) ?
 594                     &tp->t_termios_lock_out : &tp->t_termios_lock_in;
 595                 int cc;
 596
 597                 /*
 598                  * Lock state devices.  Just overwrite the values of the
 599                  * commands that are currently in use.
 600                  */
 601                 new->c_iflag = (old->c_iflag & lock->c_iflag) |
 602                     (new->c_iflag & ~lock->c_iflag);
 603                 new->c_oflag = (old->c_oflag & lock->c_oflag) |
 604                     (new->c_oflag & ~lock->c_oflag);
 605                 new->c_cflag = (old->c_cflag & lock->c_cflag) |
 606                     (new->c_cflag & ~lock->c_cflag);
 607                 new->c_lflag = (old->c_lflag & lock->c_lflag) |
 608                     (new->c_lflag & ~lock->c_lflag);
 609                 for (cc = 0; cc < NCCS; ++cc)
 610                         if (lock->c_cc[cc])
 611                                 new->c_cc[cc] = old->c_cc[cc];
 612                 if (lock->c_ispeed)
 613                         new->c_ispeed = old->c_ispeed;
 614                 if (lock->c_ospeed)
 615                         new->c_ospeed = old->c_ospeed;
 616         }
 617
 618         error = tty_ioctl(tp, cmd, data, fflag, td);
 619 done:   tty_unlock(tp);
 620
 621         return (error);
 622 }
 623
 624 static int
 625 ttydev_poll(struct cdev *dev, int events, struct thread *td)
 626 {
 627         struct tty *tp = dev->si_drv1;
 628         int error, revents = 0;
 629
 630         error = ttydev_enter(tp);
 631         if (error)
 632                 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
 633
 634         if (events & (POLLIN|POLLRDNORM)) {
 635                 /* See if we can read something. */
 636                 if (ttydisc_read_poll(tp) > 0)
 637                         revents |= events & (POLLIN|POLLRDNORM);
 638         }
 639
 640         if (tp->t_flags & TF_ZOMBIE) {
 641                 /* Hangup flag on zombie state. */
 642                 revents |= POLLHUP;
 643         } else if (events & (POLLOUT|POLLWRNORM)) {
 644                 /* See if we can write something. */
 645                 if (ttydisc_write_poll(tp) > 0)
 646                         revents |= events & (POLLOUT|POLLWRNORM);
 647         }
 648
 649         if (revents == 0) {
 650                 if (events & (POLLIN|POLLRDNORM))
 651                         selrecord(td, &tp->t_inpoll);
 652                 if (events & (POLLOUT|POLLWRNORM))
 653                         selrecord(td, &tp->t_outpoll);
 654         }
 655
 656         tty_unlock(tp);
 657
 658         return (revents);
 659 }
 660
 661 static int
 662 ttydev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
 663     int nprot, vm_memattr_t *memattr)
 664 {
 665         struct tty *tp = dev->si_drv1;
 666         int error;
 667
 668         /* Handle mmap() through the driver. */
 669
 670         error = ttydev_enter(tp);
 671         if (error)
 672                 return (-1);
 673         error = ttydevsw_mmap(tp, offset, paddr, nprot, memattr);
 674         tty_unlock(tp);
 675
 676         return (error);
 677 }
 678
 679 /*
 680  * kqueue support.
 681  */
 682
 683 static void
 684 tty_kqops_read_detach(struct knote *kn)
 685 {
 686         struct tty *tp = kn->kn_hook;
 687
 688         knlist_remove(&tp->t_inpoll.si_note, kn, 0);
 689 }
 690
 691 static int
 692 tty_kqops_read_event(struct knote *kn, long hint __unused)
 693 {
 694         struct tty *tp = kn->kn_hook;
 695
 696         tty_lock_assert(tp, MA_OWNED);
 697
 698         if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
 699                 kn->kn_flags |= EV_EOF;
 700                 return (1);
 701         } else {
 702                 kn->kn_data = ttydisc_read_poll(tp);
 703                 return (kn->kn_data > 0);
 704         }
 705 }
 706
 707 static void
 708 tty_kqops_write_detach(struct knote *kn)
 709 {
 710         struct tty *tp = kn->kn_hook;
 711
 712         knlist_remove(&tp->t_outpoll.si_note, kn, 0);
 713 }
 714
 715 static int
 716 tty_kqops_write_event(struct knote *kn, long hint __unused)
 717 {
 718         struct tty *tp = kn->kn_hook;
 719
 720         tty_lock_assert(tp, MA_OWNED);
 721
 722         if (tty_gone(tp)) {
 723                 kn->kn_flags |= EV_EOF;
 724                 return (1);
 725         } else {
 726                 kn->kn_data = ttydisc_write_poll(tp);
 727                 return (kn->kn_data > 0);
 728         }
 729 }
 730
 731 static struct filterops tty_kqops_read = {
 732         .f_isfd = 1,
 733         .f_detach = tty_kqops_read_detach,
 734         .f_event = tty_kqops_read_event,
 735 };
 736
 737 static struct filterops tty_kqops_write = {
 738         .f_isfd = 1,
 739         .f_detach = tty_kqops_write_detach,
 740         .f_event = tty_kqops_write_event,
 741 };
 742
 743 static int
 744 ttydev_kqfilter(struct cdev *dev, struct knote *kn)
 745 {
 746         struct tty *tp = dev->si_drv1;
 747         int error;
 748
 749         error = ttydev_enter(tp);
 750         if (error)
 751                 return (error);
 752
 753         switch (kn->kn_filter) {
 754         case EVFILT_READ:
 755                 kn->kn_hook = tp;
 756                 kn->kn_fop = &tty_kqops_read;
 757                 knlist_add(&tp->t_inpoll.si_note, kn, 1);
 758                 break;
 759         case EVFILT_WRITE:
 760                 kn->kn_hook = tp;
 761                 kn->kn_fop = &tty_kqops_write;
 762                 knlist_add(&tp->t_outpoll.si_note, kn, 1);
 763                 break;
 764         default:
 765                 error = EINVAL;
 766                 break;
 767         }
 768
 769         tty_unlock(tp);
 770         return (error);
 771 }
 772
 773 static struct cdevsw ttydev_cdevsw = {
 774         .d_version      = D_VERSION,
 775         .d_open         = ttydev_open,
 776         .d_close        = ttydev_close,
 777         .d_read         = ttydev_read,
 778         .d_write        = ttydev_write,
 779         .d_ioctl        = ttydev_ioctl,
 780         .d_kqfilter     = ttydev_kqfilter,
 781         .d_poll         = ttydev_poll,
 782         .d_mmap         = ttydev_mmap,
 783         .d_name         = "ttydev",
 784         .d_flags        = D_TTY,
 785 };
 786
 787 /*
 788  * Init/lock-state devices
 789  */
 790
 791 static int
 792 ttyil_open(struct cdev *dev, int oflags __unused, int devtype __unused,
 793     struct thread *td)
 794 {
 795         struct tty *tp;
 796         int error;
 797
 798         tp = dev->si_drv1;
 799         error = 0;
 800         tty_lock(tp);
 801         if (tty_gone(tp))
 802                 error = ENODEV;
 803         tty_unlock(tp);
 804
 805         return (error);
 806 }
 807
 808 static int
 809 ttyil_close(struct cdev *dev __unused, int flag __unused, int mode __unused,
 810     struct thread *td __unused)
 811 {
 812
 813         return (0);
 814 }
 815
 816 static int
 817 ttyil_rdwr(struct cdev *dev __unused, struct uio *uio __unused,
 818     int ioflag __unused)
 819 {
 820
 821         return (ENODEV);
 822 }
 823
 824 static int
 825 ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
 826     struct thread *td)
 827 {
 828         struct tty *tp = dev->si_drv1;
 829         int error;
 830
 831         tty_lock(tp);
 832         if (tty_gone(tp)) {
 833                 error = ENODEV;
 834                 goto done;
 835         }
 836
 837         error = ttydevsw_cioctl(tp, dev2unit(dev), cmd, data, td);
 838         if (error != ENOIOCTL)
 839                 goto done;
 840         error = 0;
 841
 842         switch (cmd) {
 843         case TIOCGETA:
 844                 /* Obtain terminal flags through tcgetattr(). */
 845                 *(struct termios*)data = *(struct termios*)dev->si_drv2;
 846                 break;
 847         case TIOCSETA:
 848                 /* Set terminal flags through tcsetattr(). */
 849                 error = priv_check(td, PRIV_TTY_SETA);
 850                 if (error)
 851                         break;
 852                 *(struct termios*)dev->si_drv2 = *(struct termios*)data;
 853                 break;
 854         case TIOCGETD:
 855                 *(int *)data = TTYDISC;
 856                 break;
 857         case TIOCGWINSZ:
 858                 bzero(data, sizeof(struct winsize));
 859                 break;
 860         default:
 861                 error = ENOTTY;
 862         }
 863
 864 done:   tty_unlock(tp);
 865         return (error);
 866 }
 867
 868 static struct cdevsw ttyil_cdevsw = {
 869         .d_version      = D_VERSION,
 870         .d_open         = ttyil_open,
 871         .d_close        = ttyil_close,
 872         .d_read         = ttyil_rdwr,
 873         .d_write        = ttyil_rdwr,
 874         .d_ioctl        = ttyil_ioctl,
 875         .d_name         = "ttyil",
 876         .d_flags        = D_TTY,
 877 };
 878
 879 static void
 880 tty_init_termios(struct tty *tp)
 881 {
 882         struct termios *t = &tp->t_termios_init_in;
 883
 884         t->c_cflag = TTYDEF_CFLAG;
 885         t->c_iflag = TTYDEF_IFLAG;
 886         t->c_lflag = TTYDEF_LFLAG;
 887         t->c_oflag = TTYDEF_OFLAG;
 888         t->c_ispeed = TTYDEF_SPEED;
 889         t->c_ospeed = TTYDEF_SPEED;
 890         memcpy(&t->c_cc, ttydefchars, sizeof ttydefchars);
 891
 892         tp->t_termios_init_out = *t;
 893 }
 894
 895 void
 896 tty_init_console(struct tty *tp, speed_t s)
 897 {
 898         struct termios *ti = &tp->t_termios_init_in;
 899         struct termios *to = &tp->t_termios_init_out;
 900
 901         if (s != 0) {
 902                 ti->c_ispeed = ti->c_ospeed = s;
 903                 to->c_ispeed = to->c_ospeed = s;
 904         }
 905
 906         ti->c_cflag |= CLOCAL;
 907         to->c_cflag |= CLOCAL;
 908 }
 909
 910 /*
 911  * Standard device routine implementations, mostly meant for
 912  * pseudo-terminal device drivers. When a driver creates a new terminal
 913  * device class, missing routines are patched.
 914  */
 915
 916 static int
 917 ttydevsw_defopen(struct tty *tp __unused)
 918 {
 919
 920         return (0);
 921 }
 922
 923 static void
 924 ttydevsw_defclose(struct tty *tp __unused)
 925 {
 926
 927 }
 928
 929 static void
 930 ttydevsw_defoutwakeup(struct tty *tp __unused)
 931 {
 932
 933         panic("Terminal device has output, while not implemented");
 934 }
 935
 936 static void
 937 ttydevsw_definwakeup(struct tty *tp __unused)
 938 {
 939
 940 }
 941
 942 static int
 943 ttydevsw_defioctl(struct tty *tp __unused, u_long cmd __unused,
 944     caddr_t data __unused, struct thread *td __unused)
 945 {
 946
 947         return (ENOIOCTL);
 948 }
 949
 950 static int
 951 ttydevsw_defcioctl(struct tty *tp __unused, int unit __unused,
 952     u_long cmd __unused, caddr_t data __unused, struct thread *td __unused)
 953 {
 954
 955         return (ENOIOCTL);
 956 }
 957
 958 static int
 959 ttydevsw_defparam(struct tty *tp __unused, struct termios *t)
 960 {
 961
 962         /*
 963          * Allow the baud rate to be adjusted for pseudo-devices, but at
 964          * least restrict it to 115200 to prevent excessive buffer
 965          * usage.  Also disallow 0, to prevent foot shooting.
 966          */
 967         if (t->c_ispeed < B50)
 968                 t->c_ispeed = B50;
 969         else if (t->c_ispeed > B115200)
 970                 t->c_ispeed = B115200;
 971         if (t->c_ospeed < B50)
 972                 t->c_ospeed = B50;
 973         else if (t->c_ospeed > B115200)
 974                 t->c_ospeed = B115200;
 975         t->c_cflag |= CREAD;
 976
 977         return (0);
 978 }
 979
 980 static int
 981 ttydevsw_defmodem(struct tty *tp __unused, int sigon __unused,
 982     int sigoff __unused)
 983 {
 984
 985         /* Simulate a carrier to make the TTY layer happy. */
 986         return (SER_DCD);
 987 }
 988
 989 static int
 990 ttydevsw_defmmap(struct tty *tp __unused, vm_ooffset_t offset __unused,
 991     vm_paddr_t *paddr __unused, int nprot __unused,
 992     vm_memattr_t *memattr __unused)
 993 {
 994
 995         return (-1);
 996 }
 997
 998 static void
 999 ttydevsw_defpktnotify(struct tty *tp __unused, char event __unused)
1000 {
1001
1002 }
1003
1004 static void
1005 ttydevsw_deffree(void *softc __unused)
1006 {
1007
1008         panic("Terminal device freed without a free-handler");
1009 }
1010
1011 static bool
1012 ttydevsw_defbusy(struct tty *tp __unused)
1013 {
1014
1015         return (FALSE);
1016 }
1017
1018 /*
1019  * TTY allocation and deallocation. TTY devices can be deallocated when
1020  * the driver doesn't use it anymore, when the TTY isn't a session's
1021  * controlling TTY and when the device node isn't opened through devfs.
1022  */
1023
1024 struct tty *
1025 tty_alloc(struct ttydevsw *tsw, void *sc)
1026 {
1027
1028         return (tty_alloc_mutex(tsw, sc, NULL));
1029 }
1030
1031 struct tty *
1032 tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
1033 {
1034         struct tty *tp;
1035
1036         /* Make sure the driver defines all routines. */
1037 #define PATCH_FUNC(x) do {                              \
1038         if (tsw->tsw_ ## x == NULL)                     \
1039                 tsw->tsw_ ## x = ttydevsw_def ## x;     \
1040 } while (0)
1041         PATCH_FUNC(open);
1042         PATCH_FUNC(close);
1043         PATCH_FUNC(outwakeup);
1044         PATCH_FUNC(inwakeup);
1045         PATCH_FUNC(ioctl);
1046         PATCH_FUNC(cioctl);
1047         PATCH_FUNC(param);
1048         PATCH_FUNC(modem);
1049         PATCH_FUNC(mmap);
1050         PATCH_FUNC(pktnotify);
1051         PATCH_FUNC(free);
1052         PATCH_FUNC(busy);
1053 #undef PATCH_FUNC
1054
1055         tp = malloc(sizeof(struct tty), M_TTY, M_WAITOK|M_ZERO);
1056         tp->t_devsw = tsw;
1057         tp->t_devswsoftc = sc;
1058         tp->t_flags = tsw->tsw_flags;
1059         tp->t_drainwait = tty_drainwait;
1060
1061         tty_init_termios(tp);
1062
1063         cv_init(&tp->t_inwait, "ttyin");
1064         cv_init(&tp->t_outwait, "ttyout");
1065         cv_init(&tp->t_outserwait, "ttyosr");
1066         cv_init(&tp->t_bgwait, "ttybg");
1067         cv_init(&tp->t_dcdwait, "ttydcd");
1068
1069         /* Allow drivers to use a custom mutex to lock the TTY. */
1070         if (mutex != NULL) {
1071                 tp->t_mtx = mutex;
1072         } else {
1073                 tp->t_mtx = &tp->t_mtxobj;
1074                 mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
1075         }
1076
1077         knlist_init_mtx(&tp->t_inpoll.si_note, tp->t_mtx);
1078         knlist_init_mtx(&tp->t_outpoll.si_note, tp->t_mtx);
1079
1080         return (tp);
1081 }
1082
1083 static void
1084 tty_dealloc(void *arg)
1085 {
1086         struct tty *tp = arg;
1087
1088         /*
1089          * ttyydev_leave() usually frees the i/o queues earlier, but it is
1090          * not always called between queue allocation and here.  The queues
1091          * may be allocated by ioctls on a pty control device without the
1092          * corresponding pty slave device ever being open, or after it is
1093          * closed.
1094          */
1095         ttyinq_free(&tp->t_inq);
1096         ttyoutq_free(&tp->t_outq);
1097         seldrain(&tp->t_inpoll);
1098         seldrain(&tp->t_outpoll);
1099         knlist_destroy(&tp->t_inpoll.si_note);
1100         knlist_destroy(&tp->t_outpoll.si_note);
1101
1102         cv_destroy(&tp->t_inwait);
1103         cv_destroy(&tp->t_outwait);
1104         cv_destroy(&tp->t_bgwait);
1105         cv_destroy(&tp->t_dcdwait);
1106         cv_destroy(&tp->t_outserwait);
1107
1108         if (tp->t_mtx == &tp->t_mtxobj)
1109                 mtx_destroy(&tp->t_mtxobj);
1110         ttydevsw_free(tp);
1111         free(tp, M_TTY);
1112 }
1113
1114 static void
1115 tty_rel_free(struct tty *tp)
1116 {
1117         struct cdev *dev;
1118
1119         tty_lock_assert(tp, MA_OWNED);
1120
1121 #define TF_ACTIVITY     (TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
1122         if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
1123                 /* TTY is still in use. */
1124                 tty_unlock(tp);
1125                 return;
1126         }
1127
1128         /* TTY can be deallocated. */
1129         dev = tp->t_dev;
1130         tp->t_dev = NULL;
1131         tty_unlock(tp);
1132
1133         if (dev != NULL) {
1134                 sx_xlock(&tty_list_sx);
1135                 TAILQ_REMOVE(&tty_list, tp, t_list);
1136                 tty_list_count--;
1137                 sx_xunlock(&tty_list_sx);
1138                 destroy_dev_sched_cb(dev, tty_dealloc, tp);
1139         }
1140 }
1141
1142 void
1143 tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
1144 {
1145
1146         MPASS(tp->t_sessioncnt > 0);
1147         tty_lock_assert(tp, MA_OWNED);
1148
1149         if (tp->t_pgrp == pg)
1150                 tp->t_pgrp = NULL;
1151
1152         tty_unlock(tp);
1153 }
1154
1155 void
1156 tty_rel_sess(struct tty *tp, struct session *sess)
1157 {
1158
1159         MPASS(tp->t_sessioncnt > 0);
1160
1161         /* Current session has left. */
1162         if (tp->t_session == sess) {
1163                 tp->t_session = NULL;
1164                 MPASS(tp->t_pgrp == NULL);
1165         }
1166         tp->t_sessioncnt--;
1167         tty_rel_free(tp);
1168 }
1169
1170 void
1171 tty_rel_gone(struct tty *tp)
1172 {
1173
1174         MPASS(!tty_gone(tp));
1175
1176         /* Simulate carrier removal. */
1177         ttydisc_modem(tp, 0);
1178
1179         /* Wake up all blocked threads. */
1180         tty_wakeup(tp, FREAD|FWRITE);
1181         cv_broadcast(&tp->t_bgwait);
1182         cv_broadcast(&tp->t_dcdwait);
1183
1184         tp->t_flags |= TF_GONE;
1185         tty_rel_free(tp);
1186 }
1187
1188 /*
1189  * Exposing information about current TTY's through sysctl
1190  */
1191
1192 static void
1193 tty_to_xtty(struct tty *tp, struct xtty *xt)
1194 {
1195
1196         tty_lock_assert(tp, MA_OWNED);
1197
1198         xt->xt_size = sizeof(struct xtty);
1199         xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1200         xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1201         xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1202         xt->xt_inlow = tp->t_inlow;
1203         xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1204         xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1205         xt->xt_outlow = tp->t_outlow;
1206         xt->xt_column = tp->t_column;
1207         xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1208         xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1209         xt->xt_flags = tp->t_flags;
1210         xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : (uint32_t)NODEV;
1211 }
1212
1213 static int
1214 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1215 {
1216         unsigned long lsize;
1217         struct xtty *xtlist, *xt;
1218         struct tty *tp;
1219         int error;
1220
1221         sx_slock(&tty_list_sx);
1222         lsize = tty_list_count * sizeof(struct xtty);
1223         if (lsize == 0) {
1224                 sx_sunlock(&tty_list_sx);
1225                 return (0);
1226         }
1227
1228         xtlist = xt = malloc(lsize, M_TTY, M_WAITOK);
1229
1230         TAILQ_FOREACH(tp, &tty_list, t_list) {
1231                 tty_lock(tp);
1232                 tty_to_xtty(tp, xt);
1233                 tty_unlock(tp);
1234                 xt++;
1235         }
1236         sx_sunlock(&tty_list_sx);
1237
1238         error = SYSCTL_OUT(req, xtlist, lsize);
1239         free(xtlist, M_TTY);
1240         return (error);
1241 }
1242
1243 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1244         0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1245
1246 /*
1247  * Device node creation. Device has been set up, now we can expose it to
1248  * the user.
1249  */
1250
1251 int
1252 tty_makedevf(struct tty *tp, struct ucred *cred, int flags,
1253     const char *fmt, ...)
1254 {
1255         va_list ap;
1256         struct make_dev_args args;
1257         struct cdev *dev, *init, *lock, *cua, *cinit, *clock;
1258         const char *prefix = "tty";
1259         char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1260         uid_t uid;
1261         gid_t gid;
1262         mode_t mode;
1263         int error;
1264
1265         /* Remove "tty" prefix from devices like PTY's. */
1266         if (tp->t_flags & TF_NOPREFIX)
1267                 prefix = "";
1268
1269         va_start(ap, fmt);
1270         vsnrprintf(name, sizeof name, 32, fmt, ap);
1271         va_end(ap);
1272
1273         if (cred == NULL) {
1274                 /* System device. */
1275                 uid = UID_ROOT;
1276                 gid = GID_WHEEL;
1277                 mode = S_IRUSR|S_IWUSR;
1278         } else {
1279                 /* User device. */
1280                 uid = cred->cr_ruid;
1281                 gid = GID_TTY;
1282                 mode = S_IRUSR|S_IWUSR|S_IWGRP;
1283         }
1284
1285         flags = flags & TTYMK_CLONING ? MAKEDEV_REF : 0;
1286         flags |= MAKEDEV_CHECKNAME;
1287
1288         /* Master call-in device. */
1289         make_dev_args_init(&args);
1290         args.mda_flags = flags;
1291         args.mda_devsw = &ttydev_cdevsw;
1292         args.mda_cr = cred;
1293         args.mda_uid = uid;
1294         args.mda_gid = gid;
1295         args.mda_mode = mode;
1296         args.mda_si_drv1 = tp;
1297         error = make_dev_s(&args, &dev, "%s%s", prefix, name);
1298         if (error != 0)
1299                 return (error);
1300         tp->t_dev = dev;
1301
1302         init = lock = cua = cinit = clock = NULL;
1303
1304         /* Slave call-in devices. */
1305         if (tp->t_flags & TF_INITLOCK) {
1306                 args.mda_devsw = &ttyil_cdevsw;
1307                 args.mda_unit = TTYUNIT_INIT;
1308                 args.mda_si_drv1 = tp;
1309                 args.mda_si_drv2 = &tp->t_termios_init_in;
1310                 error = make_dev_s(&args, &init, "%s%s.init", prefix, name);
1311                 if (error != 0)
1312                         goto fail;
1313                 dev_depends(dev, init);
1314
1315                 args.mda_unit = TTYUNIT_LOCK;
1316                 args.mda_si_drv2 = &tp->t_termios_lock_in;
1317                 error = make_dev_s(&args, &lock, "%s%s.lock", prefix, name);
1318                 if (error != 0)
1319                         goto fail;
1320                 dev_depends(dev, lock);
1321         }
1322
1323         /* Call-out devices. */
1324         if (tp->t_flags & TF_CALLOUT) {
1325                 make_dev_args_init(&args);
1326                 args.mda_flags = flags;
1327                 args.mda_devsw = &ttydev_cdevsw;
1328                 args.mda_cr = cred;
1329                 args.mda_uid = UID_UUCP;
1330                 args.mda_gid = GID_DIALER;
1331                 args.mda_mode = 0660;
1332                 args.mda_unit = TTYUNIT_CALLOUT;
1333                 args.mda_si_drv1 = tp;
1334                 error = make_dev_s(&args, &cua, "cua%s", name);
1335                 if (error != 0)
1336                         goto fail;
1337                 dev_depends(dev, cua);
1338
1339                 /* Slave call-out devices. */
1340                 if (tp->t_flags & TF_INITLOCK) {
1341                         args.mda_devsw = &ttyil_cdevsw;
1342                         args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_INIT;
1343                         args.mda_si_drv2 = &tp->t_termios_init_out;
1344                         error = make_dev_s(&args, &cinit, "cua%s.init", name);
1345                         if (error != 0)
1346                                 goto fail;
1347                         dev_depends(dev, cinit);
1348
1349                         args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_LOCK;
1350                         args.mda_si_drv2 = &tp->t_termios_lock_out;
1351                         error = make_dev_s(&args, &clock, "cua%s.lock", name);
1352                         if (error != 0)
1353                                 goto fail;
1354                         dev_depends(dev, clock);
1355                 }
1356         }
1357
1358         sx_xlock(&tty_list_sx);
1359         TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
1360         tty_list_count++;
1361         sx_xunlock(&tty_list_sx);
1362
1363         return (0);
1364
1365 fail:
1366         destroy_dev(dev);
1367         if (init)
1368                 destroy_dev(init);
1369         if (lock)
1370                 destroy_dev(lock);
1371         if (cinit)
1372                 destroy_dev(cinit);
1373         if (clock)
1374                 destroy_dev(clock);
1375
1376         return (error);
1377 }
1378
1379 /*
1380  * Signalling processes.
1381  */
1382
1383 void
1384 tty_signal_sessleader(struct tty *tp, int sig)
1385 {
1386         struct proc *p;
1387
1388         tty_lock_assert(tp, MA_OWNED);
1389         MPASS(sig >= 1 && sig < NSIG);
1390
1391         /* Make signals start output again. */
1392         tp->t_flags &= ~TF_STOPPED;
1393
1394         if (tp->t_session != NULL && tp->t_session->s_leader != NULL) {
1395                 p = tp->t_session->s_leader;
1396                 PROC_LOCK(p);
1397                 kern_psignal(p, sig);
1398                 PROC_UNLOCK(p);
1399         }
1400 }
1401
1402 void
1403 tty_signal_pgrp(struct tty *tp, int sig)
1404 {
1405         ksiginfo_t ksi;
1406
1407         tty_lock_assert(tp, MA_OWNED);
1408         MPASS(sig >= 1 && sig < NSIG);
1409
1410         /* Make signals start output again. */
1411         tp->t_flags &= ~TF_STOPPED;
1412
1413         if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1414                 tty_info(tp);
1415         if (tp->t_pgrp != NULL) {
1416                 ksiginfo_init(&ksi);
1417                 ksi.ksi_signo = sig;
1418                 ksi.ksi_code = SI_KERNEL;
1419                 PGRP_LOCK(tp->t_pgrp);
1420                 pgsignal(tp->t_pgrp, sig, 1, &ksi);
1421                 PGRP_UNLOCK(tp->t_pgrp);
1422         }
1423 }
1424
1425 void
1426 tty_wakeup(struct tty *tp, int flags)
1427 {
1428
1429         if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1430                 pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1431
1432         if (flags & FWRITE) {
1433                 cv_broadcast(&tp->t_outwait);
1434                 selwakeup(&tp->t_outpoll);
1435                 KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1436         }
1437         if (flags & FREAD) {
1438                 cv_broadcast(&tp->t_inwait);
1439                 selwakeup(&tp->t_inpoll);
1440                 KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1441         }
1442 }
1443
1444 int
1445 tty_wait(struct tty *tp, struct cv *cv)
1446 {
1447         int error;
1448         int revokecnt = tp->t_revokecnt;
1449
1450         tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1451         MPASS(!tty_gone(tp));
1452
1453         error = cv_wait_sig(cv, tp->t_mtx);
1454
1455         /* Bail out when the device slipped away. */
1456         if (tty_gone(tp))
1457                 return (ENXIO);
1458
1459         /* Restart the system call when we may have been revoked. */
1460         if (tp->t_revokecnt != revokecnt)
1461                 return (ERESTART);
1462
1463         return (error);
1464 }
1465
1466 int
1467 tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1468 {
1469         int error;
1470         int revokecnt = tp->t_revokecnt;
1471
1472         tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1473         MPASS(!tty_gone(tp));
1474
1475         error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1476
1477         /* Bail out when the device slipped away. */
1478         if (tty_gone(tp))
1479                 return (ENXIO);
1480
1481         /* Restart the system call when we may have been revoked. */
1482         if (tp->t_revokecnt != revokecnt)
1483                 return (ERESTART);
1484
1485         return (error);
1486 }
1487
1488 void
1489 tty_flush(struct tty *tp, int flags)
1490 {
1491
1492         if (flags & FWRITE) {
1493                 tp->t_flags &= ~TF_HIWAT_OUT;
1494                 ttyoutq_flush(&tp->t_outq);
1495                 tty_wakeup(tp, FWRITE);
1496                 if (!tty_gone(tp)) {
1497                         ttydevsw_outwakeup(tp);
1498                         ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1499                 }
1500         }
1501         if (flags & FREAD) {
1502                 tty_hiwat_in_unblock(tp);
1503                 ttyinq_flush(&tp->t_inq);
1504                 tty_wakeup(tp, FREAD);
1505                 if (!tty_gone(tp)) {
1506                         ttydevsw_inwakeup(tp);
1507                         ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1508                 }
1509         }
1510 }
1511
1512 void
1513 tty_set_winsize(struct tty *tp, const struct winsize *wsz)
1514 {
1515
1516         if (memcmp(&tp->t_winsize, wsz, sizeof(*wsz)) == 0)
1517                 return;
1518         tp->t_winsize = *wsz;
1519         tty_signal_pgrp(tp, SIGWINCH);
1520 }
1521
1522 static int
1523 tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
1524     struct thread *td)
1525 {
1526         int error;
1527
1528         switch (cmd) {
1529         /*
1530          * Modem commands.
1531          * The SER_* and TIOCM_* flags are the same, but one bit
1532          * shifted. I don't know why.
1533          */
1534         case TIOCSDTR:
1535                 ttydevsw_modem(tp, SER_DTR, 0);
1536                 return (0);
1537         case TIOCCDTR:
1538                 ttydevsw_modem(tp, 0, SER_DTR);
1539                 return (0);
1540         case TIOCMSET: {
1541                 int bits = *(int *)data;
1542                 ttydevsw_modem(tp,
1543                     (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1544                     ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1545                 return (0);
1546         }
1547         case TIOCMBIS: {
1548                 int bits = *(int *)data;
1549                 ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1550                 return (0);
1551         }
1552         case TIOCMBIC: {
1553                 int bits = *(int *)data;
1554                 ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1555                 return (0);
1556         }
1557         case TIOCMGET:
1558                 *(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1559                 return (0);
1560
1561         case FIOASYNC:
1562                 if (*(int *)data)
1563                         tp->t_flags |= TF_ASYNC;
1564                 else
1565                         tp->t_flags &= ~TF_ASYNC;
1566                 return (0);
1567         case FIONBIO:
1568                 /* This device supports non-blocking operation. */
1569                 return (0);
1570         case FIONREAD:
1571                 *(int *)data = ttyinq_bytescanonicalized(&tp->t_inq);
1572                 return (0);
1573         case FIONWRITE:
1574         case TIOCOUTQ:
1575                 *(int *)data = ttyoutq_bytesused(&tp->t_outq);
1576                 return (0);
1577         case FIOSETOWN:
1578                 if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1579                         /* Not allowed to set ownership. */
1580                         return (ENOTTY);
1581
1582                 /* Temporarily unlock the TTY to set ownership. */
1583                 tty_unlock(tp);
1584                 error = fsetown(*(int *)data, &tp->t_sigio);
1585                 tty_lock(tp);
1586                 return (error);
1587         case FIOGETOWN:
1588                 if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1589                         /* Not allowed to set ownership. */
1590                         return (ENOTTY);
1591
1592                 /* Get ownership. */
1593                 *(int *)data = fgetown(&tp->t_sigio);
1594                 return (0);
1595         case TIOCGETA:
1596                 /* Obtain terminal flags through tcgetattr(). */
1597                 *(struct termios*)data = tp->t_termios;
1598                 return (0);
1599         case TIOCSETA:
1600         case TIOCSETAW:
1601         case TIOCSETAF: {
1602                 struct termios *t = data;
1603
1604                 /*
1605                  * Who makes up these funny rules? According to POSIX,
1606                  * input baud rate is set equal to the output baud rate
1607                  * when zero.
1608                  */
1609                 if (t->c_ispeed == 0)
1610                         t->c_ispeed = t->c_ospeed;
1611
1612                 /* Discard any unsupported bits. */
1613                 t->c_iflag &= TTYSUP_IFLAG;
1614                 t->c_oflag &= TTYSUP_OFLAG;
1615                 t->c_lflag &= TTYSUP_LFLAG;
1616                 t->c_cflag &= TTYSUP_CFLAG;
1617
1618                 /* Set terminal flags through tcsetattr(). */
1619                 if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1620                         error = tty_drain(tp, 0);
1621                         if (error)
1622                                 return (error);
1623                         if (cmd == TIOCSETAF)
1624                                 tty_flush(tp, FREAD);
1625                 }
1626
1627                 /*
1628                  * Only call param() when the flags really change.
1629                  */
1630                 if ((t->c_cflag & CIGNORE) == 0 &&
1631                     (tp->t_termios.c_cflag != t->c_cflag ||
1632                     ((tp->t_termios.c_iflag ^ t->c_iflag) &
1633                     (IXON|IXOFF|IXANY)) ||
1634                     tp->t_termios.c_ispeed != t->c_ispeed ||
1635                     tp->t_termios.c_ospeed != t->c_ospeed)) {
1636                         error = ttydevsw_param(tp, t);
1637                         if (error)
1638                                 return (error);
1639
1640                         /* XXX: CLOCAL? */
1641
1642                         tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1643                         tp->t_termios.c_ispeed = t->c_ispeed;
1644                         tp->t_termios.c_ospeed = t->c_ospeed;
1645
1646                         /* Baud rate has changed - update watermarks. */
1647                         error = tty_watermarks(tp);
1648                         if (error)
1649                                 return (error);
1650                 }
1651
1652                 /* Copy new non-device driver parameters. */
1653                 tp->t_termios.c_iflag = t->c_iflag;
1654                 tp->t_termios.c_oflag = t->c_oflag;
1655                 tp->t_termios.c_lflag = t->c_lflag;
1656                 memcpy(&tp->t_termios.c_cc, t->c_cc, sizeof t->c_cc);
1657
1658                 ttydisc_optimize(tp);
1659
1660                 if ((t->c_lflag & ICANON) == 0) {
1661                         /*
1662                          * When in non-canonical mode, wake up all
1663                          * readers. Canonicalize any partial input. VMIN
1664                          * and VTIME could also be adjusted.
1665                          */
1666                         ttyinq_canonicalize(&tp->t_inq);
1667                         tty_wakeup(tp, FREAD);
1668                 }
1669
1670                 /*
1671                  * For packet mode: notify the PTY consumer that VSTOP
1672                  * and VSTART may have been changed.
1673                  */
1674                 if (tp->t_termios.c_iflag & IXON &&
1675                     tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1676                     tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1677                         ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1678                 else
1679                         ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1680                 return (0);
1681         }
1682         case TIOCGETD:
1683                 /* For compatibility - we only support TTYDISC. */
1684                 *(int *)data = TTYDISC;
1685                 return (0);
1686         case TIOCGPGRP:
1687                 if (!tty_is_ctty(tp, td->td_proc))
1688                         return (ENOTTY);
1689
1690                 if (tp->t_pgrp != NULL)
1691                         *(int *)data = tp->t_pgrp->pg_id;
1692                 else
1693                         *(int *)data = NO_PID;
1694                 return (0);
1695         case TIOCGSID:
1696                 if (!tty_is_ctty(tp, td->td_proc))
1697                         return (ENOTTY);
1698
1699                 MPASS(tp->t_session);
1700                 *(int *)data = tp->t_session->s_sid;
1701                 return (0);
1702         case TIOCSCTTY: {
1703                 struct proc *p = td->td_proc;
1704
1705                 /* XXX: This looks awful. */
1706                 tty_unlock(tp);
1707                 sx_xlock(&proctree_lock);
1708                 tty_lock(tp);
1709
1710                 if (!SESS_LEADER(p)) {
1711                         /* Only the session leader may do this. */
1712                         sx_xunlock(&proctree_lock);
1713                         return (EPERM);
1714                 }
1715
1716                 if (tp->t_session != NULL && tp->t_session == p->p_session) {
1717                         /* This is already our controlling TTY. */
1718                         sx_xunlock(&proctree_lock);
1719                         return (0);
1720                 }
1721
1722                 if (p->p_session->s_ttyp != NULL ||
1723                     (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL &&
1724                     tp->t_session->s_ttyvp->v_type != VBAD)) {
1725                         /*
1726                          * There is already a relation between a TTY and
1727                          * a session, or the caller is not the session
1728                          * leader.
1729                          *
1730                          * Allow the TTY to be stolen when the vnode is
1731                          * invalid, but the reference to the TTY is
1732                          * still active.  This allows immediate reuse of
1733                          * TTYs of which the session leader has been
1734                          * killed or the TTY revoked.
1735                          */
1736                         sx_xunlock(&proctree_lock);
1737                         return (EPERM);
1738                 }
1739
1740                 /* Connect the session to the TTY. */
1741                 tp->t_session = p->p_session;
1742                 tp->t_session->s_ttyp = tp;
1743                 tp->t_sessioncnt++;
1744                 sx_xunlock(&proctree_lock);
1745
1746                 /* Assign foreground process group. */
1747                 tp->t_pgrp = p->p_pgrp;
1748                 PROC_LOCK(p);
1749                 p->p_flag |= P_CONTROLT;
1750                 PROC_UNLOCK(p);
1751
1752                 return (0);
1753         }
1754         case TIOCSPGRP: {
1755                 struct pgrp *pg;
1756
1757                 /*
1758                  * XXX: Temporarily unlock the TTY to locate the process
1759                  * group. This code would be lot nicer if we would ever
1760                  * decompose proctree_lock.
1761                  */
1762                 tty_unlock(tp);
1763                 sx_slock(&proctree_lock);
1764                 pg = pgfind(*(int *)data);
1765                 if (pg != NULL)
1766                         PGRP_UNLOCK(pg);
1767                 if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1768                         sx_sunlock(&proctree_lock);
1769                         tty_lock(tp);
1770                         return (EPERM);
1771                 }
1772                 tty_lock(tp);
1773
1774                 /*
1775                  * Determine if this TTY is the controlling TTY after
1776                  * relocking the TTY.
1777                  */
1778                 if (!tty_is_ctty(tp, td->td_proc)) {
1779                         sx_sunlock(&proctree_lock);
1780                         return (ENOTTY);
1781                 }
1782                 tp->t_pgrp = pg;
1783                 sx_sunlock(&proctree_lock);
1784
1785                 /* Wake up the background process groups. */
1786                 cv_broadcast(&tp->t_bgwait);
1787                 return (0);
1788         }
1789         case TIOCFLUSH: {
1790                 int flags = *(int *)data;
1791
1792                 if (flags == 0)
1793                         flags = (FREAD|FWRITE);
1794                 else
1795                         flags &= (FREAD|FWRITE);
1796                 tty_flush(tp, flags);
1797                 return (0);
1798         }
1799         case TIOCDRAIN:
1800                 /* Drain TTY output. */
1801                 return tty_drain(tp, 0);
1802         case TIOCGDRAINWAIT:
1803                 *(int *)data = tp->t_drainwait;
1804                 return (0);
1805         case TIOCSDRAINWAIT:
1806                 error = priv_check(td, PRIV_TTY_DRAINWAIT);
1807                 if (error == 0)
1808                         tp->t_drainwait = *(int *)data;
1809                 return (error);
1810         case TIOCCONS:
1811                 /* Set terminal as console TTY. */
1812                 if (*(int *)data) {
1813                         error = priv_check(td, PRIV_TTY_CONSOLE);
1814                         if (error)
1815                                 return (error);
1816
1817                         /*
1818                          * XXX: constty should really need to be locked!
1819                          * XXX: allow disconnected constty's to be stolen!
1820                          */
1821
1822                         if (constty == tp)
1823                                 return (0);
1824                         if (constty != NULL)
1825                                 return (EBUSY);
1826
1827                         tty_unlock(tp);
1828                         constty_set(tp);
1829                         tty_lock(tp);
1830                 } else if (constty == tp) {
1831                         constty_clear();
1832                 }
1833                 return (0);
1834         case TIOCGWINSZ:
1835                 /* Obtain window size. */
1836                 *(struct winsize*)data = tp->t_winsize;
1837                 return (0);
1838         case TIOCSWINSZ:
1839                 /* Set window size. */
1840                 tty_set_winsize(tp, data);
1841                 return (0);
1842         case TIOCEXCL:
1843                 tp->t_flags |= TF_EXCLUDE;
1844                 return (0);
1845         case TIOCNXCL:
1846                 tp->t_flags &= ~TF_EXCLUDE;
1847                 return (0);
1848         case TIOCSTOP:
1849                 tp->t_flags |= TF_STOPPED;
1850                 ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1851                 return (0);
1852         case TIOCSTART:
1853                 tp->t_flags &= ~TF_STOPPED;
1854                 ttydevsw_outwakeup(tp);
1855                 ttydevsw_pktnotify(tp, TIOCPKT_START);
1856                 return (0);
1857         case TIOCSTAT:
1858                 tty_info(tp);
1859                 return (0);
1860         case TIOCSTI:
1861                 if ((fflag & FREAD) == 0 && priv_check(td, PRIV_TTY_STI))
1862                         return (EPERM);
1863                 if (!tty_is_ctty(tp, td->td_proc) &&
1864                     priv_check(td, PRIV_TTY_STI))
1865                         return (EACCES);
1866                 ttydisc_rint(tp, *(char *)data, 0);
1867                 ttydisc_rint_done(tp);
1868                 return (0);
1869         }
1870
1871 #ifdef COMPAT_43TTY
1872         return tty_ioctl_compat(tp, cmd, data, fflag, td);
1873 #else /* !COMPAT_43TTY */
1874         return (ENOIOCTL);
1875 #endif /* COMPAT_43TTY */
1876 }
1877
1878 int
1879 tty_ioctl(struct tty *tp, u_long cmd, void *data, int fflag, struct thread *td)
1880 {
1881         int error;
1882
1883         tty_lock_assert(tp, MA_OWNED);
1884
1885         if (tty_gone(tp))
1886                 return (ENXIO);
1887
1888         error = ttydevsw_ioctl(tp, cmd, data, td);
1889         if (error == ENOIOCTL)
1890                 error = tty_generic_ioctl(tp, cmd, data, fflag, td);
1891
1892         return (error);
1893 }
1894
1895 dev_t
1896 tty_udev(struct tty *tp)
1897 {
1898
1899         if (tp->t_dev)
1900                 return (dev2udev(tp->t_dev));
1901         else
1902                 return (NODEV);
1903 }
1904
1905 int
1906 tty_checkoutq(struct tty *tp)
1907 {
1908
1909         /* 256 bytes should be enough to print a log message. */
1910         return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
1911 }
1912
1913 void
1914 tty_hiwat_in_block(struct tty *tp)
1915 {
1916
1917         if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
1918             tp->t_termios.c_iflag & IXOFF &&
1919             tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
1920                 /*
1921                  * Input flow control. Only enter the high watermark when we
1922                  * can successfully store the VSTOP character.
1923                  */
1924                 if (ttyoutq_write_nofrag(&tp->t_outq,
1925                     &tp->t_termios.c_cc[VSTOP], 1) == 0)
1926                         tp->t_flags |= TF_HIWAT_IN;
1927         } else {
1928                 /* No input flow control. */
1929                 tp->t_flags |= TF_HIWAT_IN;
1930         }
1931 }
1932
1933 void
1934 tty_hiwat_in_unblock(struct tty *tp)
1935 {
1936
1937         if (tp->t_flags & TF_HIWAT_IN &&
1938             tp->t_termios.c_iflag & IXOFF &&
1939             tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
1940                 /*
1941                  * Input flow control. Only leave the high watermark when we
1942                  * can successfully store the VSTART character.
1943                  */
1944                 if (ttyoutq_write_nofrag(&tp->t_outq,
1945                     &tp->t_termios.c_cc[VSTART], 1) == 0)
1946                         tp->t_flags &= ~TF_HIWAT_IN;
1947         } else {
1948                 /* No input flow control. */
1949                 tp->t_flags &= ~TF_HIWAT_IN;
1950         }
1951
1952         if (!tty_gone(tp))
1953                 ttydevsw_inwakeup(tp);
1954 }
1955
1956 /*
1957  * TTY hooks interface.
1958  */
1959
1960 static int
1961 ttyhook_defrint(struct tty *tp, char c, int flags)
1962 {
1963
1964         if (ttyhook_rint_bypass(tp, &c, 1) != 1)
1965                 return (-1);
1966
1967         return (0);
1968 }
1969
1970 int
1971 ttyhook_register(struct tty **rtp, struct proc *p, int fd, struct ttyhook *th,
1972     void *softc)
1973 {
1974         struct tty *tp;
1975         struct file *fp;
1976         struct cdev *dev;
1977         struct cdevsw *cdp;
1978         struct filedesc *fdp;
1979         cap_rights_t rights;
1980         int error, ref;
1981
1982         /* Validate the file descriptor. */
1983         fdp = p->p_fd;
1984         error = fget_unlocked(fdp, fd, cap_rights_init(&rights, CAP_TTYHOOK),
1985             &fp, NULL);
1986         if (error != 0)
1987                 return (error);
1988         if (fp->f_ops == &badfileops) {
1989                 error = EBADF;
1990                 goto done1;
1991         }
1992
1993         /*
1994          * Make sure the vnode is bound to a character device.
1995          * Unlocked check for the vnode type is ok there, because we
1996          * only shall prevent calling devvn_refthread on the file that
1997          * never has been opened over a character device.
1998          */
1999         if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR) {
2000                 error = EINVAL;
2001                 goto done1;
2002         }
2003
2004         /* Make sure it is a TTY. */
2005         cdp = devvn_refthread(fp->f_vnode, &dev, &ref);
2006         if (cdp == NULL) {
2007                 error = ENXIO;
2008                 goto done1;
2009         }
2010         if (dev != fp->f_data) {
2011                 error = ENXIO;
2012                 goto done2;
2013         }
2014         if (cdp != &ttydev_cdevsw) {
2015                 error = ENOTTY;
2016                 goto done2;
2017         }
2018         tp = dev->si_drv1;
2019
2020         /* Try to attach the hook to the TTY. */
2021         error = EBUSY;
2022         tty_lock(tp);
2023         MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
2024         if (tp->t_flags & TF_HOOK)
2025                 goto done3;
2026
2027         tp->t_flags |= TF_HOOK;
2028         tp->t_hook = th;
2029         tp->t_hooksoftc = softc;
2030         *rtp = tp;
2031         error = 0;
2032
2033         /* Maybe we can switch into bypass mode now. */
2034         ttydisc_optimize(tp);
2035
2036         /* Silently convert rint() calls to rint_bypass() when possible. */
2037         if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
2038                 th->th_rint = ttyhook_defrint;
2039
2040 done3:  tty_unlock(tp);
2041 done2:  dev_relthread(dev, ref);
2042 done1:  fdrop(fp, curthread);
2043         return (error);
2044 }
2045
2046 void
2047 ttyhook_unregister(struct tty *tp)
2048 {
2049
2050         tty_lock_assert(tp, MA_OWNED);
2051         MPASS(tp->t_flags & TF_HOOK);
2052
2053         /* Disconnect the hook. */
2054         tp->t_flags &= ~TF_HOOK;
2055         tp->t_hook = NULL;
2056
2057         /* Maybe we need to leave bypass mode. */
2058         ttydisc_optimize(tp);
2059
2060         /* Maybe deallocate the TTY as well. */
2061         tty_rel_free(tp);
2062 }
2063
2064 /*
2065  * /dev/console handling.
2066  */
2067
2068 static int
2069 ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
2070 {
2071         struct tty *tp;
2072
2073         /* System has no console device. */
2074         if (dev_console_filename == NULL)
2075                 return (ENXIO);
2076
2077         /* Look up corresponding TTY by device name. */
2078         sx_slock(&tty_list_sx);
2079         TAILQ_FOREACH(tp, &tty_list, t_list) {
2080                 if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
2081                         dev_console->si_drv1 = tp;
2082                         break;
2083                 }
2084         }
2085         sx_sunlock(&tty_list_sx);
2086
2087         /* System console has no TTY associated. */
2088         if (dev_console->si_drv1 == NULL)
2089                 return (ENXIO);
2090
2091         return (ttydev_open(dev, oflags, devtype, td));
2092 }
2093
2094 static int
2095 ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
2096 {
2097
2098         log_console(uio);
2099
2100         return (ttydev_write(dev, uio, ioflag));
2101 }
2102
2103 /*
2104  * /dev/console is a little different than normal TTY's.  When opened,
2105  * it determines which TTY to use.  When data gets written to it, it
2106  * will be logged in the kernel message buffer.
2107  */
2108 static struct cdevsw ttyconsdev_cdevsw = {
2109         .d_version      = D_VERSION,
2110         .d_open         = ttyconsdev_open,
2111         .d_close        = ttydev_close,
2112         .d_read         = ttydev_read,
2113         .d_write        = ttyconsdev_write,
2114         .d_ioctl        = ttydev_ioctl,
2115         .d_kqfilter     = ttydev_kqfilter,
2116         .d_poll         = ttydev_poll,
2117         .d_mmap         = ttydev_mmap,
2118         .d_name         = "ttyconsdev",
2119         .d_flags        = D_TTY,
2120 };
2121
2122 static void
2123 ttyconsdev_init(void *unused __unused)
2124 {
2125
2126         dev_console = make_dev_credf(MAKEDEV_ETERNAL, &ttyconsdev_cdevsw, 0,
2127             NULL, UID_ROOT, GID_WHEEL, 0600, "console");
2128 }
2129
2130 SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
2131
2132 void
2133 ttyconsdev_select(const char *name)
2134 {
2135
2136         dev_console_filename = name;
2137 }
2138
2139 /*
2140  * Debugging routines.
2141  */
2142
2143 #include "opt_ddb.h"
2144 #ifdef DDB
2145 #include <ddb/ddb.h>
2146 #include <ddb/db_sym.h>
2147
2148 static const struct {
2149         int flag;
2150         char val;
2151 } ttystates[] = {
2152 #if 0
2153         { TF_NOPREFIX,          'N' },
2154 #endif
2155         { TF_INITLOCK,          'I' },
2156         { TF_CALLOUT,           'C' },
2157
2158         /* Keep these together -> 'Oi' and 'Oo'. */
2159         { TF_OPENED,            'O' },
2160         { TF_OPENED_IN,         'i' },
2161         { TF_OPENED_OUT,        'o' },
2162         { TF_OPENED_CONS,       'c' },
2163
2164         { TF_GONE,              'G' },
2165         { TF_OPENCLOSE,         'B' },
2166         { TF_ASYNC,             'Y' },
2167         { TF_LITERAL,           'L' },
2168
2169         /* Keep these together -> 'Hi' and 'Ho'. */
2170         { TF_HIWAT,             'H' },
2171         { TF_HIWAT_IN,          'i' },
2172         { TF_HIWAT_OUT,         'o' },
2173
2174         { TF_STOPPED,           'S' },
2175         { TF_EXCLUDE,           'X' },
2176         { TF_BYPASS,            'l' },
2177         { TF_ZOMBIE,            'Z' },
2178         { TF_HOOK,              's' },
2179
2180         /* Keep these together -> 'bi' and 'bo'. */
2181         { TF_BUSY,              'b' },
2182         { TF_BUSY_IN,           'i' },
2183         { TF_BUSY_OUT,          'o' },
2184
2185         { 0,                    '\0'},
2186 };
2187
2188 #define TTY_FLAG_BITS \
2189         "\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN" \
2190         "\5OPENED_OUT\6OPENED_CONS\7GONE\10OPENCLOSE" \
2191         "\11ASYNC\12LITERAL\13HIWAT_IN\14HIWAT_OUT" \
2192         "\15STOPPED\16EXCLUDE\17BYPASS\20ZOMBIE" \
2193         "\21HOOK\22BUSY_IN\23BUSY_OUT"
2194
2195 #define DB_PRINTSYM(name, addr) \
2196         db_printf("%s  " #name ": ", sep); \
2197         db_printsym((db_addr_t) addr, DB_STGY_ANY); \
2198         db_printf("\n");
2199
2200 static void
2201 _db_show_devsw(const char *sep, const struct ttydevsw *tsw)
2202 {
2203
2204         db_printf("%sdevsw: ", sep);
2205         db_printsym((db_addr_t)tsw, DB_STGY_ANY);
2206         db_printf(" (%p)\n", tsw);
2207         DB_PRINTSYM(open, tsw->tsw_open);
2208         DB_PRINTSYM(close, tsw->tsw_close);
2209         DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
2210         DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
2211         DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
2212         DB_PRINTSYM(param, tsw->tsw_param);
2213         DB_PRINTSYM(modem, tsw->tsw_modem);
2214         DB_PRINTSYM(mmap, tsw->tsw_mmap);
2215         DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
2216         DB_PRINTSYM(free, tsw->tsw_free);
2217 }
2218
2219 static void
2220 _db_show_hooks(const char *sep, const struct ttyhook *th)
2221 {
2222
2223         db_printf("%shook: ", sep);
2224         db_printsym((db_addr_t)th, DB_STGY_ANY);
2225         db_printf(" (%p)\n", th);
2226         if (th == NULL)
2227                 return;
2228         DB_PRINTSYM(rint, th->th_rint);
2229         DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
2230         DB_PRINTSYM(rint_done, th->th_rint_done);
2231         DB_PRINTSYM(rint_poll, th->th_rint_poll);
2232         DB_PRINTSYM(getc_inject, th->th_getc_inject);
2233         DB_PRINTSYM(getc_capture, th->th_getc_capture);
2234         DB_PRINTSYM(getc_poll, th->th_getc_poll);
2235         DB_PRINTSYM(close, th->th_close);
2236 }
2237
2238 static void
2239 _db_show_termios(const char *name, const struct termios *t)
2240 {
2241
2242         db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
2243             "lflag 0x%x ispeed %u ospeed %u\n", name,
2244             t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
2245             t->c_ispeed, t->c_ospeed);
2246 }
2247
2248 /* DDB command to show TTY statistics. */
2249 DB_SHOW_COMMAND(tty, db_show_tty)
2250 {
2251         struct tty *tp;
2252
2253         if (!have_addr) {
2254                 db_printf("usage: show tty <addr>\n");
2255                 return;
2256         }
2257         tp = (struct tty *)addr;
2258
2259         db_printf("%p: %s\n", tp, tty_devname(tp));
2260         db_printf("\tmtx: %p\n", tp->t_mtx);
2261         db_printf("\tflags: 0x%b\n", tp->t_flags, TTY_FLAG_BITS);
2262         db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
2263
2264         /* Buffering mechanisms. */
2265         db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
2266             "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
2267             tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
2268             tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
2269         db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
2270             &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
2271             tp->t_outq.to_nblocks, tp->t_outq.to_quota);
2272         db_printf("\tinlow: %zu\n", tp->t_inlow);
2273         db_printf("\toutlow: %zu\n", tp->t_outlow);
2274         _db_show_termios("\ttermios", &tp->t_termios);
2275         db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
2276             tp->t_winsize.ws_row, tp->t_winsize.ws_col,
2277             tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
2278         db_printf("\tcolumn: %u\n", tp->t_column);
2279         db_printf("\twritepos: %u\n", tp->t_writepos);
2280         db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
2281
2282         /* Init/lock-state devices. */
2283         _db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
2284         _db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
2285         _db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
2286         _db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
2287
2288         /* Hooks */
2289         _db_show_devsw("\t", tp->t_devsw);
2290         _db_show_hooks("\t", tp->t_hook);
2291
2292         /* Process info. */
2293         db_printf("\tpgrp: %p gid %d jobc %d\n", tp->t_pgrp,
2294             tp->t_pgrp ? tp->t_pgrp->pg_id : 0,
2295             tp->t_pgrp ? tp->t_pgrp->pg_jobc : 0);
2296         db_printf("\tsession: %p", tp->t_session);
2297         if (tp->t_session != NULL)
2298             db_printf(" count %u leader %p tty %p sid %d login %s",
2299                 tp->t_session->s_count, tp->t_session->s_leader,
2300                 tp->t_session->s_ttyp, tp->t_session->s_sid,
2301                 tp->t_session->s_login);
2302         db_printf("\n");
2303         db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
2304         db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
2305         db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
2306         db_printf("\tdev: %p\n", tp->t_dev);
2307 }
2308
2309 /* DDB command to list TTYs. */
2310 DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
2311 {
2312         struct tty *tp;
2313         size_t isiz, osiz;
2314         int i, j;
2315
2316         /* Make the output look like `pstat -t'. */
2317         db_printf("PTR        ");
2318 #if defined(__LP64__)
2319         db_printf("        ");
2320 #endif
2321         db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2322             "COL  SESS  PGID STATE\n");
2323
2324         TAILQ_FOREACH(tp, &tty_list, t_list) {
2325                 isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2326                 osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2327
2328                 db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d "
2329                     "%5d ", tp, tty_devname(tp), isiz,
2330                     tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2331                     tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2332                     isiz - tp->t_inlow, osiz,
2333                     tp->t_outq.to_end - tp->t_outq.to_begin,
2334                     osiz - tp->t_outlow, MIN(tp->t_column, 99999),
2335                     tp->t_session ? tp->t_session->s_sid : 0,
2336                     tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2337
2338                 /* Flag bits. */
2339                 for (i = j = 0; ttystates[i].flag; i++)
2340                         if (tp->t_flags & ttystates[i].flag) {
2341                                 db_printf("%c", ttystates[i].val);
2342                                 j++;
2343                         }
2344                 if (j == 0)
2345                         db_printf("-");
2346                 db_printf("\n");
2347         }
2348 }
2349 #endif /* DDB */