sys/kern/tty.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause
   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 #include "opt_capsicum.h"
  34 #include "opt_printf.h"
  35
  36 #include <sys/param.h>
  37 #include <sys/capsicum.h>
  38 #include <sys/conf.h>
  39 #include <sys/cons.h>
  40 #include <sys/fcntl.h>
  41 #include <sys/file.h>
  42 #include <sys/filedesc.h>
  43 #include <sys/filio.h>
  44 #ifdef COMPAT_43TTY
  45 #include <sys/ioctl_compat.h>
  46 #endif /* COMPAT_43TTY */
  47 #include <sys/jail.h>
  48 #include <sys/kernel.h>
  49 #include <sys/limits.h>
  50 #include <sys/malloc.h>
  51 #include <sys/mount.h>
  52 #include <sys/poll.h>
  53 #include <sys/priv.h>
  54 #include <sys/proc.h>
  55 #include <sys/serial.h>
  56 #include <sys/signal.h>
  57 #include <sys/stat.h>
  58 #include <sys/sx.h>
  59 #include <sys/sysctl.h>
  60 #include <sys/systm.h>
  61 #include <sys/tty.h>
  62 #include <sys/ttycom.h>
  63 #define TTYDEFCHARS
  64 #include <sys/ttydefaults.h>
  65 #undef TTYDEFCHARS
  66 #include <sys/ucred.h>
  67 #include <sys/vnode.h>
  68
  69 #include <fs/devfs/devfs.h>
  70
  71 #include <machine/stdarg.h>
  72
  73 static MALLOC_DEFINE(M_TTY, "tty", "tty device");
  74
  75 static void tty_rel_free(struct tty *tp);
  76
  77 static TAILQ_HEAD(, tty) tty_list = TAILQ_HEAD_INITIALIZER(tty_list);
  78 static struct sx tty_list_sx;
  79 SX_SYSINIT(tty_list, &tty_list_sx, "tty list");
  80 static unsigned int tty_list_count = 0;
  81
  82 /* Character device of /dev/console. */
  83 static struct cdev      *dev_console;
  84 static const char       *dev_console_filename;
  85
  86 /*
  87  * Flags that are supported and stored by this implementation.
  88  */
  89 #define TTYSUP_IFLAG    (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK|ISTRIP|INLCR|\
  90                         IGNCR|ICRNL|IXON|IXOFF|IXANY|IMAXBEL|IUTF8)
  91 #define TTYSUP_OFLAG    (OPOST|ONLCR|TAB3|ONOEOT|OCRNL|ONOCR|ONLRET)
  92 #define TTYSUP_LFLAG    (ECHOKE|ECHOE|ECHOK|ECHO|ECHONL|ECHOPRT|\
  93                         ECHOCTL|ISIG|ICANON|ALTWERASE|IEXTEN|TOSTOP|\
  94                         FLUSHO|NOKERNINFO|NOFLSH)
  95 #define TTYSUP_CFLAG    (CIGNORE|CSIZE|CSTOPB|CREAD|PARENB|PARODD|\
  96                         HUPCL|CLOCAL|CCTS_OFLOW|CRTS_IFLOW|CDTR_IFLOW|\
  97                         CDSR_OFLOW|CCAR_OFLOW|CNO_RTSDTR)
  98
  99 #define TTY_CALLOUT(tp,d) (dev2unit(d) & TTYUNIT_CALLOUT)
 100
 101 static int  tty_drainwait = 5 * 60;
 102 SYSCTL_INT(_kern, OID_AUTO, tty_drainwait, CTLFLAG_RWTUN,
 103     &tty_drainwait, 0, "Default output drain timeout in seconds");
 104
 105 /*
 106  * Set TTY buffer sizes.
 107  */
 108
 109 #define TTYBUF_MAX      65536
 110
 111 #ifdef PRINTF_BUFR_SIZE
 112 #define TTY_PRBUF_SIZE  PRINTF_BUFR_SIZE
 113 #else
 114 #define TTY_PRBUF_SIZE  256
 115 #endif
 116
 117 /*
 118  * Allocate buffer space if necessary, and set low watermarks, based on speed.
 119  * Note that the ttyxxxq_setsize() functions may drop and then reacquire the tty
 120  * lock during memory allocation.  They will return ENXIO if the tty disappears
 121  * while unlocked.
 122  */
 123 static int
 124 tty_watermarks(struct tty *tp)
 125 {
 126         size_t bs = 0;
 127         int error;
 128
 129         /* Provide an input buffer for 2 seconds of data. */
 130         if (tp->t_termios.c_cflag & CREAD)
 131                 bs = MIN(tp->t_termios.c_ispeed / 5, TTYBUF_MAX);
 132         error = ttyinq_setsize(&tp->t_inq, tp, bs);
 133         if (error != 0)
 134                 return (error);
 135
 136         /* Set low watermark at 10% (when 90% is available). */
 137         tp->t_inlow = (ttyinq_getallocatedsize(&tp->t_inq) * 9) / 10;
 138
 139         /* Provide an output buffer for 2 seconds of data. */
 140         bs = MIN(tp->t_termios.c_ospeed / 5, TTYBUF_MAX);
 141         error = ttyoutq_setsize(&tp->t_outq, tp, bs);
 142         if (error != 0)
 143                 return (error);
 144
 145         /* Set low watermark at 10% (when 90% is available). */
 146         tp->t_outlow = (ttyoutq_getallocatedsize(&tp->t_outq) * 9) / 10;
 147
 148         return (0);
 149 }
 150
 151 static int
 152 tty_drain(struct tty *tp, int leaving)
 153 {
 154         sbintime_t timeout_at;
 155         size_t bytes;
 156         int error;
 157
 158         if (ttyhook_hashook(tp, getc_inject))
 159                 /* buffer is inaccessible */
 160                 return (0);
 161
 162         /*
 163          * For close(), use the recent historic timeout of "1 second without
 164          * making progress".  For tcdrain(), use t_drainwait as the timeout,
 165          * with zero meaning "no timeout" which gives POSIX behavior.
 166          */
 167         if (leaving)
 168                 timeout_at = getsbinuptime() + SBT_1S;
 169         else if (tp->t_drainwait != 0)
 170                 timeout_at = getsbinuptime() + SBT_1S * tp->t_drainwait;
 171         else
 172                 timeout_at = 0;
 173
 174         /*
 175          * Poll the output buffer and the hardware for completion, at 10 Hz.
 176          * Polling is required for devices which are not able to signal an
 177          * interrupt when the transmitter becomes idle (most USB serial devs).
 178          * The unusual structure of this loop ensures we check for busy one more
 179          * time after tty_timedwait() returns EWOULDBLOCK, so that success has
 180          * higher priority than timeout if the IO completed in the last 100mS.
 181          */
 182         error = 0;
 183         bytes = ttyoutq_bytesused(&tp->t_outq);
 184         for (;;) {
 185                 if (ttyoutq_bytesused(&tp->t_outq) == 0 && !ttydevsw_busy(tp))
 186                         return (0);
 187                 if (error != 0)
 188                         return (error);
 189                 ttydevsw_outwakeup(tp);
 190                 error = tty_timedwait(tp, &tp->t_outwait, hz / 10);
 191                 if (error != 0 && error != EWOULDBLOCK)
 192                         return (error);
 193                 else if (timeout_at == 0 || getsbinuptime() < timeout_at)
 194                         error = 0;
 195                 else if (leaving && ttyoutq_bytesused(&tp->t_outq) < bytes) {
 196                         /* In close, making progress, grant an extra second. */
 197                         error = 0;
 198                         timeout_at += SBT_1S;
 199                         bytes = ttyoutq_bytesused(&tp->t_outq);
 200                 }
 201         }
 202 }
 203
 204 /*
 205  * Though ttydev_enter() and ttydev_leave() seem to be related, they
 206  * don't have to be used together. ttydev_enter() is used by the cdev
 207  * operations to prevent an actual operation from being processed when
 208  * the TTY has been abandoned. ttydev_leave() is used by ttydev_open()
 209  * and ttydev_close() to determine whether per-TTY data should be
 210  * deallocated.
 211  */
 212
 213 static __inline int
 214 ttydev_enter(struct tty *tp)
 215 {
 216
 217         tty_lock(tp);
 218
 219         if (tty_gone(tp) || !tty_opened(tp)) {
 220                 /* Device is already gone. */
 221                 tty_unlock(tp);
 222                 return (ENXIO);
 223         }
 224
 225         return (0);
 226 }
 227
 228 static void
 229 ttydev_leave(struct tty *tp)
 230 {
 231
 232         tty_assert_locked(tp);
 233
 234         if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
 235                 /* Device is still opened somewhere. */
 236                 tty_unlock(tp);
 237                 return;
 238         }
 239
 240         tp->t_flags |= TF_OPENCLOSE;
 241
 242         /* Remove console TTY. */
 243         constty_clear(tp);
 244
 245         /* Drain any output. */
 246         if (!tty_gone(tp))
 247                 tty_drain(tp, 1);
 248
 249         ttydisc_close(tp);
 250
 251         /* Free i/o queues now since they might be large. */
 252         ttyinq_free(&tp->t_inq);
 253         tp->t_inlow = 0;
 254         ttyoutq_free(&tp->t_outq);
 255         tp->t_outlow = 0;
 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                 if ((tp->t_termios.c_cflag & CNO_RTSDTR) == 0)
 330                         ttydevsw_modem(tp, SER_DTR|SER_RTS, 0);
 331
 332                 error = ttydevsw_open(tp);
 333                 if (error != 0)
 334                         goto done;
 335
 336                 ttydisc_open(tp);
 337                 error = tty_watermarks(tp);
 338                 if (error != 0)
 339                         goto done;
 340         }
 341
 342         /* Wait for Carrier Detect. */
 343         if ((oflags & O_NONBLOCK) == 0 &&
 344             (tp->t_termios.c_cflag & CLOCAL) == 0) {
 345                 while ((ttydevsw_modem(tp, 0, 0) & SER_DCD) == 0) {
 346                         error = tty_wait(tp, &tp->t_dcdwait);
 347                         if (error != 0)
 348                                 goto done;
 349                 }
 350         }
 351
 352         if (dev == dev_console)
 353                 tp->t_flags |= TF_OPENED_CONS;
 354         else if (TTY_CALLOUT(tp, dev))
 355                 tp->t_flags |= TF_OPENED_OUT;
 356         else
 357                 tp->t_flags |= TF_OPENED_IN;
 358         MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
 359             (tp->t_flags & TF_OPENED_OUT) == 0);
 360
 361 done:   tp->t_flags &= ~TF_OPENCLOSE;
 362         cv_broadcast(&tp->t_dcdwait);
 363         ttydev_leave(tp);
 364
 365         return (error);
 366 }
 367
 368 static int
 369 ttydev_close(struct cdev *dev, int fflag, int devtype __unused,
 370     struct thread *td)
 371 {
 372         struct tty *tp = dev->si_drv1;
 373
 374         tty_lock(tp);
 375
 376         /*
 377          * Don't actually close the device if it is being used as the
 378          * console.
 379          */
 380         MPASS((tp->t_flags & (TF_OPENED_CONS | TF_OPENED_IN)) == 0 ||
 381             (tp->t_flags & TF_OPENED_OUT) == 0);
 382         if (dev == dev_console)
 383                 tp->t_flags &= ~TF_OPENED_CONS;
 384         else
 385                 tp->t_flags &= ~(TF_OPENED_IN|TF_OPENED_OUT);
 386
 387         if (tp->t_flags & TF_OPENED) {
 388                 tty_unlock(tp);
 389                 return (0);
 390         }
 391
 392         /* If revoking, flush output now to avoid draining it later. */
 393         if ((fflag & FREVOKE) != 0) {
 394                 tty_flush(tp, FWRITE);
 395                 knlist_delete(&tp->t_inpoll.si_note, td, 1);
 396                 knlist_delete(&tp->t_outpoll.si_note, td, 1);
 397         }
 398
 399         tp->t_flags &= ~TF_EXCLUDE;
 400
 401         /* Properly wake up threads that are stuck - revoke(). */
 402         tp->t_revokecnt++;
 403         tty_wakeup(tp, FREAD|FWRITE);
 404         cv_broadcast(&tp->t_bgwait);
 405         cv_broadcast(&tp->t_dcdwait);
 406
 407         ttydev_leave(tp);
 408
 409         return (0);
 410 }
 411
 412 static __inline int
 413 tty_is_ctty(struct tty *tp, struct proc *p)
 414 {
 415
 416         tty_assert_locked(tp);
 417
 418         return (p->p_session == tp->t_session && p->p_flag & P_CONTROLT);
 419 }
 420
 421 int
 422 tty_wait_background(struct tty *tp, struct thread *td, int sig)
 423 {
 424         struct proc *p;
 425         struct pgrp *pg;
 426         ksiginfo_t ksi;
 427         int error;
 428
 429         MPASS(sig == SIGTTIN || sig == SIGTTOU);
 430         tty_assert_locked(tp);
 431
 432         p = td->td_proc;
 433         for (;;) {
 434                 pg = p->p_pgrp;
 435                 PGRP_LOCK(pg);
 436                 PROC_LOCK(p);
 437
 438                 /*
 439                  * pg may no longer be our process group.
 440                  * Re-check after locking.
 441                  */
 442                 if (p->p_pgrp != pg) {
 443                         PROC_UNLOCK(p);
 444                         PGRP_UNLOCK(pg);
 445                         continue;
 446                 }
 447
 448                 /*
 449                  * The process should only sleep, when:
 450                  * - This terminal is the controlling terminal
 451                  * - Its process group is not the foreground process
 452                  *   group
 453                  * - The parent process isn't waiting for the child to
 454                  *   exit
 455                  * - the signal to send to the process isn't masked
 456                  */
 457                 if (!tty_is_ctty(tp, p) || p->p_pgrp == tp->t_pgrp) {
 458                         /* Allow the action to happen. */
 459                         PROC_UNLOCK(p);
 460                         PGRP_UNLOCK(pg);
 461                         return (0);
 462                 }
 463
 464                 if (SIGISMEMBER(p->p_sigacts->ps_sigignore, sig) ||
 465                     SIGISMEMBER(td->td_sigmask, sig)) {
 466                         /* Only allow them in write()/ioctl(). */
 467                         PROC_UNLOCK(p);
 468                         PGRP_UNLOCK(pg);
 469                         return (sig == SIGTTOU ? 0 : EIO);
 470                 }
 471
 472                 if ((p->p_flag & P_PPWAIT) != 0 ||
 473                     (pg->pg_flags & PGRP_ORPHANED) != 0) {
 474                         /* Don't allow the action to happen. */
 475                         PROC_UNLOCK(p);
 476                         PGRP_UNLOCK(pg);
 477                         return (EIO);
 478                 }
 479                 PROC_UNLOCK(p);
 480
 481                 /*
 482                  * Send the signal and sleep until we're the new
 483                  * foreground process group.
 484                  */
 485                 if (sig != 0) {
 486                         ksiginfo_init(&ksi);
 487                         ksi.ksi_code = SI_KERNEL;
 488                         ksi.ksi_signo = sig;
 489                         sig = 0;
 490                 }
 491
 492                 pgsignal(pg, ksi.ksi_signo, 1, &ksi);
 493                 PGRP_UNLOCK(pg);
 494
 495                 error = tty_wait(tp, &tp->t_bgwait);
 496                 if (error)
 497                         return (error);
 498         }
 499 }
 500
 501 static int
 502 ttydev_read(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                 goto done;
 510         error = ttydisc_read(tp, uio, ioflag);
 511         tty_unlock(tp);
 512
 513         /*
 514          * The read() call should not throw an error when the device is
 515          * being destroyed. Silently convert it to an EOF.
 516          */
 517 done:   if (error == ENXIO)
 518                 error = 0;
 519         return (error);
 520 }
 521
 522 static int
 523 ttydev_write(struct cdev *dev, struct uio *uio, int ioflag)
 524 {
 525         struct tty *tp = dev->si_drv1;
 526         int defer, error;
 527
 528         error = ttydev_enter(tp);
 529         if (error)
 530                 return (error);
 531
 532         if (tp->t_termios.c_lflag & TOSTOP) {
 533                 error = tty_wait_background(tp, curthread, SIGTTOU);
 534                 if (error)
 535                         goto done;
 536         }
 537
 538         if (ioflag & IO_NDELAY && tp->t_flags & TF_BUSY_OUT) {
 539                 /* Allow non-blocking writes to bypass serialization. */
 540                 error = ttydisc_write(tp, uio, ioflag);
 541         } else {
 542                 /* Serialize write() calls. */
 543                 while (tp->t_flags & TF_BUSY_OUT) {
 544                         error = tty_wait(tp, &tp->t_outserwait);
 545                         if (error)
 546                                 goto done;
 547                 }
 548
 549                 tp->t_flags |= TF_BUSY_OUT;
 550                 defer = sigdeferstop(SIGDEFERSTOP_ERESTART);
 551                 error = ttydisc_write(tp, uio, ioflag);
 552                 sigallowstop(defer);
 553                 tp->t_flags &= ~TF_BUSY_OUT;
 554                 cv_signal(&tp->t_outserwait);
 555         }
 556
 557 done:   tty_unlock(tp);
 558         return (error);
 559 }
 560
 561 static int
 562 ttydev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
 563     struct thread *td)
 564 {
 565         struct tty *tp = dev->si_drv1;
 566         int error;
 567
 568         error = ttydev_enter(tp);
 569         if (error)
 570                 return (error);
 571
 572         switch (cmd) {
 573         case TIOCCBRK:
 574         case TIOCCONS:
 575         case TIOCDRAIN:
 576         case TIOCEXCL:
 577         case TIOCFLUSH:
 578         case TIOCNXCL:
 579         case TIOCSBRK:
 580         case TIOCSCTTY:
 581         case TIOCSETA:
 582         case TIOCSETAF:
 583         case TIOCSETAW:
 584         case TIOCSPGRP:
 585         case TIOCSTART:
 586         case TIOCSTAT:
 587         case TIOCSTI:
 588         case TIOCSTOP:
 589         case TIOCSWINSZ:
 590 #if 0
 591         case TIOCSDRAINWAIT:
 592         case TIOCSETD:
 593 #endif
 594 #ifdef COMPAT_43TTY
 595         case  TIOCLBIC:
 596         case  TIOCLBIS:
 597         case  TIOCLSET:
 598         case  TIOCSETC:
 599         case OTIOCSETD:
 600         case  TIOCSETN:
 601         case  TIOCSETP:
 602         case  TIOCSLTC:
 603 #endif /* COMPAT_43TTY */
 604                 /*
 605                  * If the ioctl() causes the TTY to be modified, let it
 606                  * wait in the background.
 607                  */
 608                 error = tty_wait_background(tp, curthread, SIGTTOU);
 609                 if (error)
 610                         goto done;
 611         }
 612
 613         if (cmd == TIOCSETA || cmd == TIOCSETAW || cmd == TIOCSETAF) {
 614                 struct termios *old = &tp->t_termios;
 615                 struct termios *new = (struct termios *)data;
 616                 struct termios *lock = TTY_CALLOUT(tp, dev) ?
 617                     &tp->t_termios_lock_out : &tp->t_termios_lock_in;
 618                 int cc;
 619
 620                 /*
 621                  * Lock state devices.  Just overwrite the values of the
 622                  * commands that are currently in use.
 623                  */
 624                 new->c_iflag = (old->c_iflag & lock->c_iflag) |
 625                     (new->c_iflag & ~lock->c_iflag);
 626                 new->c_oflag = (old->c_oflag & lock->c_oflag) |
 627                     (new->c_oflag & ~lock->c_oflag);
 628                 new->c_cflag = (old->c_cflag & lock->c_cflag) |
 629                     (new->c_cflag & ~lock->c_cflag);
 630                 new->c_lflag = (old->c_lflag & lock->c_lflag) |
 631                     (new->c_lflag & ~lock->c_lflag);
 632                 for (cc = 0; cc < NCCS; ++cc)
 633                         if (lock->c_cc[cc])
 634                                 new->c_cc[cc] = old->c_cc[cc];
 635                 if (lock->c_ispeed)
 636                         new->c_ispeed = old->c_ispeed;
 637                 if (lock->c_ospeed)
 638                         new->c_ospeed = old->c_ospeed;
 639         }
 640
 641         error = tty_ioctl(tp, cmd, data, fflag, td);
 642 done:   tty_unlock(tp);
 643
 644         return (error);
 645 }
 646
 647 static int
 648 ttydev_poll(struct cdev *dev, int events, struct thread *td)
 649 {
 650         struct tty *tp = dev->si_drv1;
 651         int error, revents = 0;
 652
 653         error = ttydev_enter(tp);
 654         if (error)
 655                 return ((events & (POLLIN|POLLRDNORM)) | POLLHUP);
 656
 657         if (events & (POLLIN|POLLRDNORM)) {
 658                 /* See if we can read something. */
 659                 if (ttydisc_read_poll(tp) > 0)
 660                         revents |= events & (POLLIN|POLLRDNORM);
 661         }
 662
 663         if (tp->t_flags & TF_ZOMBIE) {
 664                 /* Hangup flag on zombie state. */
 665                 revents |= POLLHUP;
 666         } else if (events & (POLLOUT|POLLWRNORM)) {
 667                 /* See if we can write something. */
 668                 if (ttydisc_write_poll(tp) > 0)
 669                         revents |= events & (POLLOUT|POLLWRNORM);
 670         }
 671
 672         if (revents == 0) {
 673                 if (events & (POLLIN|POLLRDNORM))
 674                         selrecord(td, &tp->t_inpoll);
 675                 if (events & (POLLOUT|POLLWRNORM))
 676                         selrecord(td, &tp->t_outpoll);
 677         }
 678
 679         tty_unlock(tp);
 680
 681         return (revents);
 682 }
 683
 684 static int
 685 ttydev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
 686     int nprot, vm_memattr_t *memattr)
 687 {
 688         struct tty *tp = dev->si_drv1;
 689         int error;
 690
 691         /* Handle mmap() through the driver. */
 692
 693         error = ttydev_enter(tp);
 694         if (error)
 695                 return (-1);
 696         error = ttydevsw_mmap(tp, offset, paddr, nprot, memattr);
 697         tty_unlock(tp);
 698
 699         return (error);
 700 }
 701
 702 /*
 703  * kqueue support.
 704  */
 705
 706 static void
 707 tty_kqops_read_detach(struct knote *kn)
 708 {
 709         struct tty *tp = kn->kn_hook;
 710
 711         knlist_remove(&tp->t_inpoll.si_note, kn, 0);
 712 }
 713
 714 static int
 715 tty_kqops_read_event(struct knote *kn, long hint __unused)
 716 {
 717         struct tty *tp = kn->kn_hook;
 718
 719         tty_assert_locked(tp);
 720
 721         if (tty_gone(tp) || tp->t_flags & TF_ZOMBIE) {
 722                 kn->kn_flags |= EV_EOF;
 723                 return (1);
 724         } else {
 725                 kn->kn_data = ttydisc_read_poll(tp);
 726                 return (kn->kn_data > 0);
 727         }
 728 }
 729
 730 static void
 731 tty_kqops_write_detach(struct knote *kn)
 732 {
 733         struct tty *tp = kn->kn_hook;
 734
 735         knlist_remove(&tp->t_outpoll.si_note, kn, 0);
 736 }
 737
 738 static int
 739 tty_kqops_write_event(struct knote *kn, long hint __unused)
 740 {
 741         struct tty *tp = kn->kn_hook;
 742
 743         tty_assert_locked(tp);
 744
 745         if (tty_gone(tp)) {
 746                 kn->kn_flags |= EV_EOF;
 747                 return (1);
 748         } else {
 749                 kn->kn_data = ttydisc_write_poll(tp);
 750                 return (kn->kn_data > 0);
 751         }
 752 }
 753
 754 static struct filterops tty_kqops_read = {
 755         .f_isfd = 1,
 756         .f_detach = tty_kqops_read_detach,
 757         .f_event = tty_kqops_read_event,
 758 };
 759
 760 static struct filterops tty_kqops_write = {
 761         .f_isfd = 1,
 762         .f_detach = tty_kqops_write_detach,
 763         .f_event = tty_kqops_write_event,
 764 };
 765
 766 static int
 767 ttydev_kqfilter(struct cdev *dev, struct knote *kn)
 768 {
 769         struct tty *tp = dev->si_drv1;
 770         int error;
 771
 772         error = ttydev_enter(tp);
 773         if (error)
 774                 return (error);
 775
 776         switch (kn->kn_filter) {
 777         case EVFILT_READ:
 778                 kn->kn_hook = tp;
 779                 kn->kn_fop = &tty_kqops_read;
 780                 knlist_add(&tp->t_inpoll.si_note, kn, 1);
 781                 break;
 782         case EVFILT_WRITE:
 783                 kn->kn_hook = tp;
 784                 kn->kn_fop = &tty_kqops_write;
 785                 knlist_add(&tp->t_outpoll.si_note, kn, 1);
 786                 break;
 787         default:
 788                 error = EINVAL;
 789                 break;
 790         }
 791
 792         tty_unlock(tp);
 793         return (error);
 794 }
 795
 796 static struct cdevsw ttydev_cdevsw = {
 797         .d_version      = D_VERSION,
 798         .d_open         = ttydev_open,
 799         .d_close        = ttydev_close,
 800         .d_read         = ttydev_read,
 801         .d_write        = ttydev_write,
 802         .d_ioctl        = ttydev_ioctl,
 803         .d_kqfilter     = ttydev_kqfilter,
 804         .d_poll         = ttydev_poll,
 805         .d_mmap         = ttydev_mmap,
 806         .d_name         = "ttydev",
 807         .d_flags        = D_TTY,
 808 };
 809
 810 /*
 811  * Init/lock-state devices
 812  */
 813
 814 static int
 815 ttyil_open(struct cdev *dev, int oflags __unused, int devtype __unused,
 816     struct thread *td)
 817 {
 818         struct tty *tp;
 819         int error;
 820
 821         tp = dev->si_drv1;
 822         error = 0;
 823         tty_lock(tp);
 824         if (tty_gone(tp))
 825                 error = ENODEV;
 826         tty_unlock(tp);
 827
 828         return (error);
 829 }
 830
 831 static int
 832 ttyil_close(struct cdev *dev __unused, int flag __unused, int mode __unused,
 833     struct thread *td __unused)
 834 {
 835
 836         return (0);
 837 }
 838
 839 static int
 840 ttyil_rdwr(struct cdev *dev __unused, struct uio *uio __unused,
 841     int ioflag __unused)
 842 {
 843
 844         return (ENODEV);
 845 }
 846
 847 static int
 848 ttyil_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
 849     struct thread *td)
 850 {
 851         struct tty *tp = dev->si_drv1;
 852         int error;
 853
 854         tty_lock(tp);
 855         if (tty_gone(tp)) {
 856                 error = ENODEV;
 857                 goto done;
 858         }
 859
 860         error = ttydevsw_cioctl(tp, dev2unit(dev), cmd, data, td);
 861         if (error != ENOIOCTL)
 862                 goto done;
 863         error = 0;
 864
 865         switch (cmd) {
 866         case TIOCGETA:
 867                 /* Obtain terminal flags through tcgetattr(). */
 868                 *(struct termios*)data = *(struct termios*)dev->si_drv2;
 869                 break;
 870         case TIOCSETA:
 871                 /* Set terminal flags through tcsetattr(). */
 872                 error = priv_check(td, PRIV_TTY_SETA);
 873                 if (error)
 874                         break;
 875                 *(struct termios*)dev->si_drv2 = *(struct termios*)data;
 876                 break;
 877         case TIOCGETD:
 878                 *(int *)data = TTYDISC;
 879                 break;
 880         case TIOCGWINSZ:
 881                 bzero(data, sizeof(struct winsize));
 882                 break;
 883         default:
 884                 error = ENOTTY;
 885         }
 886
 887 done:   tty_unlock(tp);
 888         return (error);
 889 }
 890
 891 static struct cdevsw ttyil_cdevsw = {
 892         .d_version      = D_VERSION,
 893         .d_open         = ttyil_open,
 894         .d_close        = ttyil_close,
 895         .d_read         = ttyil_rdwr,
 896         .d_write        = ttyil_rdwr,
 897         .d_ioctl        = ttyil_ioctl,
 898         .d_name         = "ttyil",
 899         .d_flags        = D_TTY,
 900 };
 901
 902 static void
 903 tty_init_termios(struct tty *tp)
 904 {
 905         struct termios *t = &tp->t_termios_init_in;
 906
 907         t->c_cflag = TTYDEF_CFLAG;
 908         t->c_iflag = TTYDEF_IFLAG;
 909         t->c_lflag = TTYDEF_LFLAG;
 910         t->c_oflag = TTYDEF_OFLAG;
 911         t->c_ispeed = TTYDEF_SPEED;
 912         t->c_ospeed = TTYDEF_SPEED;
 913         memcpy(&t->c_cc, ttydefchars, sizeof ttydefchars);
 914
 915         tp->t_termios_init_out = *t;
 916 }
 917
 918 void
 919 tty_init_console(struct tty *tp, speed_t s)
 920 {
 921         struct termios *ti = &tp->t_termios_init_in;
 922         struct termios *to = &tp->t_termios_init_out;
 923
 924         if (s != 0) {
 925                 ti->c_ispeed = ti->c_ospeed = s;
 926                 to->c_ispeed = to->c_ospeed = s;
 927         }
 928
 929         ti->c_cflag |= CLOCAL;
 930         to->c_cflag |= CLOCAL;
 931 }
 932
 933 /*
 934  * Standard device routine implementations, mostly meant for
 935  * pseudo-terminal device drivers. When a driver creates a new terminal
 936  * device class, missing routines are patched.
 937  */
 938
 939 static int
 940 ttydevsw_defopen(struct tty *tp __unused)
 941 {
 942
 943         return (0);
 944 }
 945
 946 static void
 947 ttydevsw_defclose(struct tty *tp __unused)
 948 {
 949
 950 }
 951
 952 static void
 953 ttydevsw_defoutwakeup(struct tty *tp __unused)
 954 {
 955
 956         panic("Terminal device has output, while not implemented");
 957 }
 958
 959 static void
 960 ttydevsw_definwakeup(struct tty *tp __unused)
 961 {
 962
 963 }
 964
 965 static int
 966 ttydevsw_defioctl(struct tty *tp __unused, u_long cmd __unused,
 967     caddr_t data __unused, struct thread *td __unused)
 968 {
 969
 970         return (ENOIOCTL);
 971 }
 972
 973 static int
 974 ttydevsw_defcioctl(struct tty *tp __unused, int unit __unused,
 975     u_long cmd __unused, caddr_t data __unused, struct thread *td __unused)
 976 {
 977
 978         return (ENOIOCTL);
 979 }
 980
 981 static int
 982 ttydevsw_defparam(struct tty *tp __unused, struct termios *t)
 983 {
 984
 985         /*
 986          * Allow the baud rate to be adjusted for pseudo-devices, but at
 987          * least restrict it to 115200 to prevent excessive buffer
 988          * usage.  Also disallow 0, to prevent foot shooting.
 989          */
 990         if (t->c_ispeed < B50)
 991                 t->c_ispeed = B50;
 992         else if (t->c_ispeed > B115200)
 993                 t->c_ispeed = B115200;
 994         if (t->c_ospeed < B50)
 995                 t->c_ospeed = B50;
 996         else if (t->c_ospeed > B115200)
 997                 t->c_ospeed = B115200;
 998         t->c_cflag |= CREAD;
 999
1000         return (0);
1001 }
1002
1003 static int
1004 ttydevsw_defmodem(struct tty *tp __unused, int sigon __unused,
1005     int sigoff __unused)
1006 {
1007
1008         /* Simulate a carrier to make the TTY layer happy. */
1009         return (SER_DCD);
1010 }
1011
1012 static int
1013 ttydevsw_defmmap(struct tty *tp __unused, vm_ooffset_t offset __unused,
1014     vm_paddr_t *paddr __unused, int nprot __unused,
1015     vm_memattr_t *memattr __unused)
1016 {
1017
1018         return (-1);
1019 }
1020
1021 static void
1022 ttydevsw_defpktnotify(struct tty *tp __unused, char event __unused)
1023 {
1024
1025 }
1026
1027 static void
1028 ttydevsw_deffree(void *softc __unused)
1029 {
1030
1031         panic("Terminal device freed without a free-handler");
1032 }
1033
1034 static bool
1035 ttydevsw_defbusy(struct tty *tp __unused)
1036 {
1037
1038         return (FALSE);
1039 }
1040
1041 /*
1042  * TTY allocation and deallocation. TTY devices can be deallocated when
1043  * the driver doesn't use it anymore, when the TTY isn't a session's
1044  * controlling TTY and when the device node isn't opened through devfs.
1045  */
1046
1047 struct tty *
1048 tty_alloc(struct ttydevsw *tsw, void *sc)
1049 {
1050
1051         return (tty_alloc_mutex(tsw, sc, NULL));
1052 }
1053
1054 struct tty *
1055 tty_alloc_mutex(struct ttydevsw *tsw, void *sc, struct mtx *mutex)
1056 {
1057         struct tty *tp;
1058
1059         /* Make sure the driver defines all routines. */
1060 #define PATCH_FUNC(x) do {                              \
1061         if (tsw->tsw_ ## x == NULL)                     \
1062                 tsw->tsw_ ## x = ttydevsw_def ## x;     \
1063 } while (0)
1064         PATCH_FUNC(open);
1065         PATCH_FUNC(close);
1066         PATCH_FUNC(outwakeup);
1067         PATCH_FUNC(inwakeup);
1068         PATCH_FUNC(ioctl);
1069         PATCH_FUNC(cioctl);
1070         PATCH_FUNC(param);
1071         PATCH_FUNC(modem);
1072         PATCH_FUNC(mmap);
1073         PATCH_FUNC(pktnotify);
1074         PATCH_FUNC(free);
1075         PATCH_FUNC(busy);
1076 #undef PATCH_FUNC
1077
1078         tp = malloc(sizeof(struct tty) + TTY_PRBUF_SIZE, M_TTY,
1079             M_WAITOK | M_ZERO);
1080         tp->t_prbufsz = TTY_PRBUF_SIZE;
1081         tp->t_devsw = tsw;
1082         tp->t_devswsoftc = sc;
1083         tp->t_flags = tsw->tsw_flags;
1084         tp->t_drainwait = tty_drainwait;
1085
1086         tty_init_termios(tp);
1087
1088         cv_init(&tp->t_inwait, "ttyin");
1089         cv_init(&tp->t_outwait, "ttyout");
1090         cv_init(&tp->t_outserwait, "ttyosr");
1091         cv_init(&tp->t_bgwait, "ttybg");
1092         cv_init(&tp->t_dcdwait, "ttydcd");
1093
1094         /* Allow drivers to use a custom mutex to lock the TTY. */
1095         if (mutex != NULL) {
1096                 tp->t_mtx = mutex;
1097         } else {
1098                 tp->t_mtx = &tp->t_mtxobj;
1099                 mtx_init(&tp->t_mtxobj, "ttymtx", NULL, MTX_DEF);
1100         }
1101
1102         knlist_init_mtx(&tp->t_inpoll.si_note, tp->t_mtx);
1103         knlist_init_mtx(&tp->t_outpoll.si_note, tp->t_mtx);
1104
1105         return (tp);
1106 }
1107
1108 static void
1109 tty_dealloc(void *arg)
1110 {
1111         struct tty *tp = arg;
1112
1113         /*
1114          * ttyydev_leave() usually frees the i/o queues earlier, but it is
1115          * not always called between queue allocation and here.  The queues
1116          * may be allocated by ioctls on a pty control device without the
1117          * corresponding pty slave device ever being open, or after it is
1118          * closed.
1119          */
1120         ttyinq_free(&tp->t_inq);
1121         ttyoutq_free(&tp->t_outq);
1122         seldrain(&tp->t_inpoll);
1123         seldrain(&tp->t_outpoll);
1124         knlist_clear(&tp->t_inpoll.si_note, 0);
1125         knlist_clear(&tp->t_outpoll.si_note, 0);
1126         knlist_destroy(&tp->t_inpoll.si_note);
1127         knlist_destroy(&tp->t_outpoll.si_note);
1128
1129         cv_destroy(&tp->t_inwait);
1130         cv_destroy(&tp->t_outwait);
1131         cv_destroy(&tp->t_bgwait);
1132         cv_destroy(&tp->t_dcdwait);
1133         cv_destroy(&tp->t_outserwait);
1134
1135         if (tp->t_mtx == &tp->t_mtxobj)
1136                 mtx_destroy(&tp->t_mtxobj);
1137         ttydevsw_free(tp);
1138         free(tp, M_TTY);
1139 }
1140
1141 static void
1142 tty_rel_free(struct tty *tp)
1143 {
1144         struct cdev *dev;
1145
1146         tty_assert_locked(tp);
1147
1148 #define TF_ACTIVITY     (TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
1149         if (tp->t_sessioncnt != 0 || (tp->t_flags & TF_ACTIVITY) != TF_GONE) {
1150                 /* TTY is still in use. */
1151                 tty_unlock(tp);
1152                 return;
1153         }
1154
1155         /* Stop asynchronous I/O. */
1156         funsetown(&tp->t_sigio);
1157
1158         /* TTY can be deallocated. */
1159         dev = tp->t_dev;
1160         tp->t_dev = NULL;
1161         tty_unlock(tp);
1162
1163         if (dev != NULL) {
1164                 sx_xlock(&tty_list_sx);
1165                 TAILQ_REMOVE(&tty_list, tp, t_list);
1166                 tty_list_count--;
1167                 sx_xunlock(&tty_list_sx);
1168                 destroy_dev_sched_cb(dev, tty_dealloc, tp);
1169         }
1170 }
1171
1172 void
1173 tty_rel_pgrp(struct tty *tp, struct pgrp *pg)
1174 {
1175
1176         MPASS(tp->t_sessioncnt > 0);
1177         tty_assert_locked(tp);
1178
1179         if (tp->t_pgrp == pg)
1180                 tp->t_pgrp = NULL;
1181
1182         tty_unlock(tp);
1183 }
1184
1185 void
1186 tty_rel_sess(struct tty *tp, struct session *sess)
1187 {
1188
1189         MPASS(tp->t_sessioncnt > 0);
1190
1191         /* Current session has left. */
1192         if (tp->t_session == sess) {
1193                 tp->t_session = NULL;
1194                 MPASS(tp->t_pgrp == NULL);
1195         }
1196         tp->t_sessioncnt--;
1197         tty_rel_free(tp);
1198 }
1199
1200 void
1201 tty_rel_gone(struct tty *tp)
1202 {
1203
1204         tty_assert_locked(tp);
1205         MPASS(!tty_gone(tp));
1206
1207         /* Simulate carrier removal. */
1208         ttydisc_modem(tp, 0);
1209
1210         /* Wake up all blocked threads. */
1211         tty_wakeup(tp, FREAD|FWRITE);
1212         cv_broadcast(&tp->t_bgwait);
1213         cv_broadcast(&tp->t_dcdwait);
1214
1215         tp->t_flags |= TF_GONE;
1216         tty_rel_free(tp);
1217 }
1218
1219 static int
1220 tty_drop_ctty(struct tty *tp, struct proc *p)
1221 {
1222         struct session *session;
1223         struct vnode *vp;
1224
1225         /*
1226          * This looks terrible, but it's generally safe as long as the tty
1227          * hasn't gone away while we had the lock dropped.  All of our sanity
1228          * checking that this operation is OK happens after we've picked it back
1229          * up, so other state changes are generally not fatal and the potential
1230          * for this particular operation to happen out-of-order in a
1231          * multithreaded scenario is likely a non-issue.
1232          */
1233         tty_unlock(tp);
1234         sx_xlock(&proctree_lock);
1235         tty_lock(tp);
1236         if (tty_gone(tp)) {
1237                 sx_xunlock(&proctree_lock);
1238                 return (ENODEV);
1239         }
1240
1241         /*
1242          * If the session doesn't have a controlling TTY, or if we weren't
1243          * invoked on the controlling TTY, we'll return ENOIOCTL as we've
1244          * historically done.
1245          */
1246         session = p->p_session;
1247         if (session->s_ttyp == NULL || session->s_ttyp != tp) {
1248                 sx_xunlock(&proctree_lock);
1249                 return (ENOTTY);
1250         }
1251
1252         if (!SESS_LEADER(p)) {
1253                 sx_xunlock(&proctree_lock);
1254                 return (EPERM);
1255         }
1256
1257         PROC_LOCK(p);
1258         SESS_LOCK(session);
1259         vp = session->s_ttyvp;
1260         session->s_ttyp = NULL;
1261         session->s_ttyvp = NULL;
1262         session->s_ttydp = NULL;
1263         SESS_UNLOCK(session);
1264
1265         tp->t_sessioncnt--;
1266         p->p_flag &= ~P_CONTROLT;
1267         PROC_UNLOCK(p);
1268         sx_xunlock(&proctree_lock);
1269
1270         /*
1271          * If we did have a vnode, release our reference.  Ordinarily we manage
1272          * these at the devfs layer, but we can't necessarily know that we were
1273          * invoked on the vnode referenced in the session (i.e. the vnode we
1274          * hold a reference to).  We explicitly don't check VBAD/VIRF_DOOMED here
1275          * to avoid a vnode leak -- in circumstances elsewhere where we'd hit a
1276          * VIRF_DOOMED vnode, release has been deferred until the controlling TTY
1277          * is either changed or released.
1278          */
1279         if (vp != NULL)
1280                 devfs_ctty_unref(vp);
1281         return (0);
1282 }
1283
1284 /*
1285  * Exposing information about current TTY's through sysctl
1286  */
1287
1288 static void
1289 tty_to_xtty(struct tty *tp, struct xtty *xt)
1290 {
1291
1292         tty_assert_locked(tp);
1293
1294         memset(xt, 0, sizeof(*xt));
1295         xt->xt_size = sizeof(struct xtty);
1296         xt->xt_insize = ttyinq_getsize(&tp->t_inq);
1297         xt->xt_incc = ttyinq_bytescanonicalized(&tp->t_inq);
1298         xt->xt_inlc = ttyinq_bytesline(&tp->t_inq);
1299         xt->xt_inlow = tp->t_inlow;
1300         xt->xt_outsize = ttyoutq_getsize(&tp->t_outq);
1301         xt->xt_outcc = ttyoutq_bytesused(&tp->t_outq);
1302         xt->xt_outlow = tp->t_outlow;
1303         xt->xt_column = tp->t_column;
1304         xt->xt_pgid = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
1305         xt->xt_sid = tp->t_session ? tp->t_session->s_sid : 0;
1306         xt->xt_flags = tp->t_flags;
1307         xt->xt_dev = tp->t_dev ? dev2udev(tp->t_dev) : (uint32_t)NODEV;
1308 }
1309
1310 static int
1311 sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
1312 {
1313         unsigned long lsize;
1314         struct thread *td = curthread;
1315         struct xtty *xtlist, *xt;
1316         struct tty *tp;
1317         struct proc *p;
1318         int error;
1319         bool cansee;
1320
1321         sx_slock(&tty_list_sx);
1322         lsize = tty_list_count * sizeof(struct xtty);
1323         if (lsize == 0) {
1324                 sx_sunlock(&tty_list_sx);
1325                 return (0);
1326         }
1327
1328         xtlist = xt = malloc(lsize, M_TTY, M_WAITOK);
1329
1330         TAILQ_FOREACH(tp, &tty_list, t_list) {
1331                 tty_lock(tp);
1332                 if (tp->t_session != NULL &&
1333                     (p = atomic_load_ptr(&tp->t_session->s_leader)) != NULL) {
1334                         PROC_LOCK(p);
1335                         cansee = (p_cansee(td, p) == 0);
1336                         PROC_UNLOCK(p);
1337                 } else {
1338                         cansee = !jailed(td->td_ucred);
1339                 }
1340                 if (cansee) {
1341                         tty_to_xtty(tp, xt);
1342                         xt++;
1343                 }
1344                 tty_unlock(tp);
1345         }
1346         sx_sunlock(&tty_list_sx);
1347
1348         lsize = (xt - xtlist) * sizeof(struct xtty);
1349         if (lsize > 0) {
1350                 error = SYSCTL_OUT(req, xtlist, lsize);
1351         } else {
1352                 error = 0;
1353         }
1354         free(xtlist, M_TTY);
1355         return (error);
1356 }
1357
1358 SYSCTL_PROC(_kern, OID_AUTO, ttys, CTLTYPE_OPAQUE|CTLFLAG_RD|CTLFLAG_MPSAFE,
1359         0, 0, sysctl_kern_ttys, "S,xtty", "List of TTYs");
1360
1361 /*
1362  * Device node creation. Device has been set up, now we can expose it to
1363  * the user.
1364  */
1365
1366 int
1367 tty_makedevf(struct tty *tp, struct ucred *cred, int flags,
1368     const char *fmt, ...)
1369 {
1370         va_list ap;
1371         struct make_dev_args args;
1372         struct cdev *dev, *init, *lock, *cua, *cinit, *clock;
1373         const char *prefix = "tty";
1374         char name[SPECNAMELEN - 3]; /* for "tty" and "cua". */
1375         uid_t uid;
1376         gid_t gid;
1377         mode_t mode;
1378         int error;
1379
1380         /* Remove "tty" prefix from devices like PTY's. */
1381         if (tp->t_flags & TF_NOPREFIX)
1382                 prefix = "";
1383
1384         va_start(ap, fmt);
1385         vsnrprintf(name, sizeof name, 32, fmt, ap);
1386         va_end(ap);
1387
1388         if (cred == NULL) {
1389                 /* System device. */
1390                 uid = UID_ROOT;
1391                 gid = GID_WHEEL;
1392                 mode = S_IRUSR|S_IWUSR;
1393         } else {
1394                 /* User device. */
1395                 uid = cred->cr_ruid;
1396                 gid = GID_TTY;
1397                 mode = S_IRUSR|S_IWUSR|S_IWGRP;
1398         }
1399
1400         flags = flags & TTYMK_CLONING ? MAKEDEV_REF : 0;
1401         flags |= MAKEDEV_CHECKNAME;
1402
1403         /* Master call-in device. */
1404         make_dev_args_init(&args);
1405         args.mda_flags = flags;
1406         args.mda_devsw = &ttydev_cdevsw;
1407         args.mda_cr = cred;
1408         args.mda_uid = uid;
1409         args.mda_gid = gid;
1410         args.mda_mode = mode;
1411         args.mda_si_drv1 = tp;
1412         error = make_dev_s(&args, &dev, "%s%s", prefix, name);
1413         if (error != 0)
1414                 return (error);
1415         tp->t_dev = dev;
1416
1417         init = lock = cua = cinit = clock = NULL;
1418
1419         /* Slave call-in devices. */
1420         if (tp->t_flags & TF_INITLOCK) {
1421                 args.mda_devsw = &ttyil_cdevsw;
1422                 args.mda_unit = TTYUNIT_INIT;
1423                 args.mda_si_drv1 = tp;
1424                 args.mda_si_drv2 = &tp->t_termios_init_in;
1425                 error = make_dev_s(&args, &init, "%s%s.init", prefix, name);
1426                 if (error != 0)
1427                         goto fail;
1428                 dev_depends(dev, init);
1429
1430                 args.mda_unit = TTYUNIT_LOCK;
1431                 args.mda_si_drv2 = &tp->t_termios_lock_in;
1432                 error = make_dev_s(&args, &lock, "%s%s.lock", prefix, name);
1433                 if (error != 0)
1434                         goto fail;
1435                 dev_depends(dev, lock);
1436         }
1437
1438         /* Call-out devices. */
1439         if (tp->t_flags & TF_CALLOUT) {
1440                 make_dev_args_init(&args);
1441                 args.mda_flags = flags;
1442                 args.mda_devsw = &ttydev_cdevsw;
1443                 args.mda_cr = cred;
1444                 args.mda_uid = UID_UUCP;
1445                 args.mda_gid = GID_DIALER;
1446                 args.mda_mode = 0660;
1447                 args.mda_unit = TTYUNIT_CALLOUT;
1448                 args.mda_si_drv1 = tp;
1449                 error = make_dev_s(&args, &cua, "cua%s", name);
1450                 if (error != 0)
1451                         goto fail;
1452                 dev_depends(dev, cua);
1453
1454                 /* Slave call-out devices. */
1455                 if (tp->t_flags & TF_INITLOCK) {
1456                         args.mda_devsw = &ttyil_cdevsw;
1457                         args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_INIT;
1458                         args.mda_si_drv2 = &tp->t_termios_init_out;
1459                         error = make_dev_s(&args, &cinit, "cua%s.init", name);
1460                         if (error != 0)
1461                                 goto fail;
1462                         dev_depends(dev, cinit);
1463
1464                         args.mda_unit = TTYUNIT_CALLOUT | TTYUNIT_LOCK;
1465                         args.mda_si_drv2 = &tp->t_termios_lock_out;
1466                         error = make_dev_s(&args, &clock, "cua%s.lock", name);
1467                         if (error != 0)
1468                                 goto fail;
1469                         dev_depends(dev, clock);
1470                 }
1471         }
1472
1473         sx_xlock(&tty_list_sx);
1474         TAILQ_INSERT_TAIL(&tty_list, tp, t_list);
1475         tty_list_count++;
1476         sx_xunlock(&tty_list_sx);
1477
1478         return (0);
1479
1480 fail:
1481         destroy_dev(dev);
1482         if (init)
1483                 destroy_dev(init);
1484         if (lock)
1485                 destroy_dev(lock);
1486         if (cinit)
1487                 destroy_dev(cinit);
1488         if (clock)
1489                 destroy_dev(clock);
1490
1491         return (error);
1492 }
1493
1494 /*
1495  * Signalling processes.
1496  */
1497
1498 void
1499 tty_signal_sessleader(struct tty *tp, int sig)
1500 {
1501         struct proc *p;
1502         struct session *s;
1503
1504         tty_assert_locked(tp);
1505         MPASS(sig >= 1 && sig < NSIG);
1506
1507         /* Make signals start output again. */
1508         tp->t_flags &= ~TF_STOPPED;
1509         tp->t_termios.c_lflag &= ~FLUSHO;
1510
1511         /*
1512          * Load s_leader exactly once to avoid race where s_leader is
1513          * set to NULL by a concurrent invocation of killjobc() by the
1514          * session leader.  Note that we are not holding t_session's
1515          * lock for the read.
1516          */
1517         if ((s = tp->t_session) != NULL &&
1518             (p = atomic_load_ptr(&s->s_leader)) != NULL) {
1519                 PROC_LOCK(p);
1520                 kern_psignal(p, sig);
1521                 PROC_UNLOCK(p);
1522         }
1523 }
1524
1525 void
1526 tty_signal_pgrp(struct tty *tp, int sig)
1527 {
1528         ksiginfo_t ksi;
1529
1530         tty_assert_locked(tp);
1531         MPASS(sig >= 1 && sig < NSIG);
1532
1533         /* Make signals start output again. */
1534         tp->t_flags &= ~TF_STOPPED;
1535         tp->t_termios.c_lflag &= ~FLUSHO;
1536
1537         if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
1538                 tty_info(tp);
1539         if (tp->t_pgrp != NULL) {
1540                 ksiginfo_init(&ksi);
1541                 ksi.ksi_signo = sig;
1542                 ksi.ksi_code = SI_KERNEL;
1543                 PGRP_LOCK(tp->t_pgrp);
1544                 pgsignal(tp->t_pgrp, sig, 1, &ksi);
1545                 PGRP_UNLOCK(tp->t_pgrp);
1546         }
1547 }
1548
1549 void
1550 tty_wakeup(struct tty *tp, int flags)
1551 {
1552
1553         if (tp->t_flags & TF_ASYNC && tp->t_sigio != NULL)
1554                 pgsigio(&tp->t_sigio, SIGIO, (tp->t_session != NULL));
1555
1556         if (flags & FWRITE) {
1557                 cv_broadcast(&tp->t_outwait);
1558                 selwakeup(&tp->t_outpoll);
1559                 KNOTE_LOCKED(&tp->t_outpoll.si_note, 0);
1560         }
1561         if (flags & FREAD) {
1562                 cv_broadcast(&tp->t_inwait);
1563                 selwakeup(&tp->t_inpoll);
1564                 KNOTE_LOCKED(&tp->t_inpoll.si_note, 0);
1565         }
1566 }
1567
1568 int
1569 tty_wait(struct tty *tp, struct cv *cv)
1570 {
1571         int error;
1572         int revokecnt = tp->t_revokecnt;
1573
1574         tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1575         MPASS(!tty_gone(tp));
1576
1577         error = cv_wait_sig(cv, tp->t_mtx);
1578
1579         /* Bail out when the device slipped away. */
1580         if (tty_gone(tp))
1581                 return (ENXIO);
1582
1583         /* Restart the system call when we may have been revoked. */
1584         if (tp->t_revokecnt != revokecnt)
1585                 return (ERESTART);
1586
1587         return (error);
1588 }
1589
1590 int
1591 tty_timedwait(struct tty *tp, struct cv *cv, int hz)
1592 {
1593         int error;
1594         int revokecnt = tp->t_revokecnt;
1595
1596         tty_lock_assert(tp, MA_OWNED|MA_NOTRECURSED);
1597         MPASS(!tty_gone(tp));
1598
1599         error = cv_timedwait_sig(cv, tp->t_mtx, hz);
1600
1601         /* Bail out when the device slipped away. */
1602         if (tty_gone(tp))
1603                 return (ENXIO);
1604
1605         /* Restart the system call when we may have been revoked. */
1606         if (tp->t_revokecnt != revokecnt)
1607                 return (ERESTART);
1608
1609         return (error);
1610 }
1611
1612 void
1613 tty_flush(struct tty *tp, int flags)
1614 {
1615
1616         if (flags & FWRITE) {
1617                 tp->t_flags &= ~TF_HIWAT_OUT;
1618                 ttyoutq_flush(&tp->t_outq);
1619                 tty_wakeup(tp, FWRITE);
1620                 if (!tty_gone(tp)) {
1621                         ttydevsw_outwakeup(tp);
1622                         ttydevsw_pktnotify(tp, TIOCPKT_FLUSHWRITE);
1623                 }
1624         }
1625         if (flags & FREAD) {
1626                 tty_hiwat_in_unblock(tp);
1627                 ttyinq_flush(&tp->t_inq);
1628                 tty_wakeup(tp, FREAD);
1629                 if (!tty_gone(tp)) {
1630                         ttydevsw_inwakeup(tp);
1631                         ttydevsw_pktnotify(tp, TIOCPKT_FLUSHREAD);
1632                 }
1633         }
1634 }
1635
1636 void
1637 tty_set_winsize(struct tty *tp, const struct winsize *wsz)
1638 {
1639
1640         if (memcmp(&tp->t_winsize, wsz, sizeof(*wsz)) == 0)
1641                 return;
1642         tp->t_winsize = *wsz;
1643         tty_signal_pgrp(tp, SIGWINCH);
1644 }
1645
1646 static int
1647 tty_generic_ioctl(struct tty *tp, u_long cmd, void *data, int fflag,
1648     struct thread *td)
1649 {
1650         int error;
1651
1652         switch (cmd) {
1653         /*
1654          * Modem commands.
1655          * The SER_* and TIOCM_* flags are the same, but one bit
1656          * shifted. I don't know why.
1657          */
1658         case TIOCSDTR:
1659                 ttydevsw_modem(tp, SER_DTR, 0);
1660                 return (0);
1661         case TIOCCDTR:
1662                 ttydevsw_modem(tp, 0, SER_DTR);
1663                 return (0);
1664         case TIOCMSET: {
1665                 int bits = *(int *)data;
1666                 ttydevsw_modem(tp,
1667                     (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1,
1668                     ((~bits) & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1669                 return (0);
1670         }
1671         case TIOCMBIS: {
1672                 int bits = *(int *)data;
1673                 ttydevsw_modem(tp, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1, 0);
1674                 return (0);
1675         }
1676         case TIOCMBIC: {
1677                 int bits = *(int *)data;
1678                 ttydevsw_modem(tp, 0, (bits & (TIOCM_DTR | TIOCM_RTS)) >> 1);
1679                 return (0);
1680         }
1681         case TIOCMGET:
1682                 *(int *)data = TIOCM_LE + (ttydevsw_modem(tp, 0, 0) << 1);
1683                 return (0);
1684
1685         case FIOASYNC:
1686                 if (*(int *)data)
1687                         tp->t_flags |= TF_ASYNC;
1688                 else
1689                         tp->t_flags &= ~TF_ASYNC;
1690                 return (0);
1691         case FIONBIO:
1692                 /* This device supports non-blocking operation. */
1693                 return (0);
1694         case FIONREAD:
1695                 *(int *)data = ttydisc_bytesavail(tp);
1696                 return (0);
1697         case FIONWRITE:
1698         case TIOCOUTQ:
1699                 *(int *)data = ttyoutq_bytesused(&tp->t_outq);
1700                 return (0);
1701         case FIOSETOWN:
1702                 if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1703                         /* Not allowed to set ownership. */
1704                         return (ENOTTY);
1705
1706                 /* Temporarily unlock the TTY to set ownership. */
1707                 tty_unlock(tp);
1708                 error = fsetown(*(int *)data, &tp->t_sigio);
1709                 tty_lock(tp);
1710                 return (error);
1711         case FIOGETOWN:
1712                 if (tp->t_session != NULL && !tty_is_ctty(tp, td->td_proc))
1713                         /* Not allowed to set ownership. */
1714                         return (ENOTTY);
1715
1716                 /* Get ownership. */
1717                 *(int *)data = fgetown(&tp->t_sigio);
1718                 return (0);
1719         case TIOCGETA:
1720                 /* Obtain terminal flags through tcgetattr(). */
1721                 *(struct termios*)data = tp->t_termios;
1722                 return (0);
1723         case TIOCSETA:
1724         case TIOCSETAW:
1725         case TIOCSETAF: {
1726                 struct termios *t = data;
1727                 bool canonicalize = false;
1728
1729                 /*
1730                  * Who makes up these funny rules? According to POSIX,
1731                  * input baud rate is set equal to the output baud rate
1732                  * when zero.
1733                  */
1734                 if (t->c_ispeed == 0)
1735                         t->c_ispeed = t->c_ospeed;
1736
1737                 /* Discard any unsupported bits. */
1738                 t->c_iflag &= TTYSUP_IFLAG;
1739                 t->c_oflag &= TTYSUP_OFLAG;
1740                 t->c_lflag &= TTYSUP_LFLAG;
1741                 t->c_cflag &= TTYSUP_CFLAG;
1742
1743                 /* Set terminal flags through tcsetattr(). */
1744                 if (cmd == TIOCSETAW || cmd == TIOCSETAF) {
1745                         error = tty_drain(tp, 0);
1746                         if (error)
1747                                 return (error);
1748                         if (cmd == TIOCSETAF)
1749                                 tty_flush(tp, FREAD);
1750                 }
1751
1752                 /*
1753                  * Only call param() when the flags really change.
1754                  */
1755                 if ((t->c_cflag & CIGNORE) == 0 &&
1756                     (tp->t_termios.c_cflag != t->c_cflag ||
1757                     ((tp->t_termios.c_iflag ^ t->c_iflag) &
1758                     (IXON|IXOFF|IXANY)) ||
1759                     tp->t_termios.c_ispeed != t->c_ispeed ||
1760                     tp->t_termios.c_ospeed != t->c_ospeed)) {
1761                         error = ttydevsw_param(tp, t);
1762                         if (error)
1763                                 return (error);
1764
1765                         /* XXX: CLOCAL? */
1766
1767                         tp->t_termios.c_cflag = t->c_cflag & ~CIGNORE;
1768                         tp->t_termios.c_ispeed = t->c_ispeed;
1769                         tp->t_termios.c_ospeed = t->c_ospeed;
1770
1771                         /* Baud rate has changed - update watermarks. */
1772                         error = tty_watermarks(tp);
1773                         if (error)
1774                                 return (error);
1775                 }
1776
1777                 /*
1778                  * We'll canonicalize any partial input if we're transitioning
1779                  * ICANON one way or the other.  If we're going from -ICANON ->
1780                  * ICANON, then in the worst case scenario we're in the middle
1781                  * of a line but both ttydisc_read() and FIONREAD will search
1782                  * for one of our line terminals.
1783                  */
1784                 if ((t->c_lflag & ICANON) != (tp->t_termios.c_lflag & ICANON))
1785                         canonicalize = true;
1786                 else if (tp->t_termios.c_cc[VEOF] != t->c_cc[VEOF] ||
1787                     tp->t_termios.c_cc[VEOL] != t->c_cc[VEOL])
1788                         canonicalize = true;
1789
1790                 /* Copy new non-device driver parameters. */
1791                 tp->t_termios.c_iflag = t->c_iflag;
1792                 tp->t_termios.c_oflag = t->c_oflag;
1793                 tp->t_termios.c_lflag = t->c_lflag;
1794                 memcpy(&tp->t_termios.c_cc, t->c_cc, sizeof t->c_cc);
1795
1796                 ttydisc_optimize(tp);
1797
1798                 if (canonicalize)
1799                         ttydisc_canonicalize(tp);
1800                 if ((t->c_lflag & ICANON) == 0) {
1801                         /*
1802                          * When in non-canonical mode, wake up all
1803                          * readers. Any partial input has already been
1804                          * canonicalized above if we were in canonical mode.
1805                          * VMIN and VTIME could also be adjusted.
1806                          */
1807                         tty_wakeup(tp, FREAD);
1808                 }
1809
1810                 /*
1811                  * For packet mode: notify the PTY consumer that VSTOP
1812                  * and VSTART may have been changed.
1813                  */
1814                 if (tp->t_termios.c_iflag & IXON &&
1815                     tp->t_termios.c_cc[VSTOP] == CTRL('S') &&
1816                     tp->t_termios.c_cc[VSTART] == CTRL('Q'))
1817                         ttydevsw_pktnotify(tp, TIOCPKT_DOSTOP);
1818                 else
1819                         ttydevsw_pktnotify(tp, TIOCPKT_NOSTOP);
1820                 return (0);
1821         }
1822         case TIOCGETD:
1823                 /* For compatibility - we only support TTYDISC. */
1824                 *(int *)data = TTYDISC;
1825                 return (0);
1826         case TIOCGPGRP:
1827                 if (!tty_is_ctty(tp, td->td_proc))
1828                         return (ENOTTY);
1829
1830                 if (tp->t_pgrp != NULL)
1831                         *(int *)data = tp->t_pgrp->pg_id;
1832                 else
1833                         *(int *)data = NO_PID;
1834                 return (0);
1835         case TIOCGSID:
1836                 if (!tty_is_ctty(tp, td->td_proc))
1837                         return (ENOTTY);
1838
1839                 MPASS(tp->t_session);
1840                 *(int *)data = tp->t_session->s_sid;
1841                 return (0);
1842         case TIOCNOTTY:
1843                 return (tty_drop_ctty(tp, td->td_proc));
1844         case TIOCSCTTY: {
1845                 struct proc *p = td->td_proc;
1846
1847                 /* XXX: This looks awful. */
1848                 tty_unlock(tp);
1849                 sx_xlock(&proctree_lock);
1850                 tty_lock(tp);
1851
1852                 if (!SESS_LEADER(p)) {
1853                         /* Only the session leader may do this. */
1854                         sx_xunlock(&proctree_lock);
1855                         return (EPERM);
1856                 }
1857
1858                 if (tp->t_session != NULL && tp->t_session == p->p_session) {
1859                         /* This is already our controlling TTY. */
1860                         sx_xunlock(&proctree_lock);
1861                         return (0);
1862                 }
1863
1864                 if (p->p_session->s_ttyp != NULL ||
1865                     (tp->t_session != NULL && tp->t_session->s_ttyvp != NULL &&
1866                     tp->t_session->s_ttyvp->v_type != VBAD)) {
1867                         /*
1868                          * There is already a relation between a TTY and
1869                          * a session, or the caller is not the session
1870                          * leader.
1871                          *
1872                          * Allow the TTY to be stolen when the vnode is
1873                          * invalid, but the reference to the TTY is
1874                          * still active.  This allows immediate reuse of
1875                          * TTYs of which the session leader has been
1876                          * killed or the TTY revoked.
1877                          */
1878                         sx_xunlock(&proctree_lock);
1879                         return (EPERM);
1880                 }
1881
1882                 /* Connect the session to the TTY. */
1883                 tp->t_session = p->p_session;
1884                 tp->t_session->s_ttyp = tp;
1885                 tp->t_sessioncnt++;
1886
1887                 /* Assign foreground process group. */
1888                 tp->t_pgrp = p->p_pgrp;
1889                 PROC_LOCK(p);
1890                 p->p_flag |= P_CONTROLT;
1891                 PROC_UNLOCK(p);
1892
1893                 sx_xunlock(&proctree_lock);
1894                 return (0);
1895         }
1896         case TIOCSPGRP: {
1897                 struct pgrp *pg;
1898
1899                 /*
1900                  * XXX: Temporarily unlock the TTY to locate the process
1901                  * group. This code would be lot nicer if we would ever
1902                  * decompose proctree_lock.
1903                  */
1904                 tty_unlock(tp);
1905                 sx_slock(&proctree_lock);
1906                 pg = pgfind(*(int *)data);
1907                 if (pg != NULL)
1908                         PGRP_UNLOCK(pg);
1909                 if (pg == NULL || pg->pg_session != td->td_proc->p_session) {
1910                         sx_sunlock(&proctree_lock);
1911                         tty_lock(tp);
1912                         return (EPERM);
1913                 }
1914                 tty_lock(tp);
1915
1916                 /*
1917                  * Determine if this TTY is the controlling TTY after
1918                  * relocking the TTY.
1919                  */
1920                 if (!tty_is_ctty(tp, td->td_proc)) {
1921                         sx_sunlock(&proctree_lock);
1922                         return (ENOTTY);
1923                 }
1924                 tp->t_pgrp = pg;
1925                 sx_sunlock(&proctree_lock);
1926
1927                 /* Wake up the background process groups. */
1928                 cv_broadcast(&tp->t_bgwait);
1929                 return (0);
1930         }
1931         case TIOCFLUSH: {
1932                 int flags = *(int *)data;
1933
1934                 if (flags == 0)
1935                         flags = (FREAD|FWRITE);
1936                 else
1937                         flags &= (FREAD|FWRITE);
1938                 tty_flush(tp, flags);
1939                 return (0);
1940         }
1941         case TIOCDRAIN:
1942                 /* Drain TTY output. */
1943                 return tty_drain(tp, 0);
1944         case TIOCGDRAINWAIT:
1945                 *(int *)data = tp->t_drainwait;
1946                 return (0);
1947         case TIOCSDRAINWAIT:
1948                 error = priv_check(td, PRIV_TTY_DRAINWAIT);
1949                 if (error == 0)
1950                         tp->t_drainwait = *(int *)data;
1951                 return (error);
1952         case TIOCCONS:
1953                 /* Set terminal as console TTY. */
1954                 if (*(int *)data) {
1955                         error = priv_check(td, PRIV_TTY_CONSOLE);
1956                         if (error)
1957                                 return (error);
1958                         error = constty_set(tp);
1959                 } else {
1960                         error = constty_clear(tp);
1961                 }
1962                 return (error);
1963         case TIOCGWINSZ:
1964                 /* Obtain window size. */
1965                 *(struct winsize*)data = tp->t_winsize;
1966                 return (0);
1967         case TIOCSWINSZ:
1968                 /* Set window size. */
1969                 tty_set_winsize(tp, data);
1970                 return (0);
1971         case TIOCEXCL:
1972                 tp->t_flags |= TF_EXCLUDE;
1973                 return (0);
1974         case TIOCNXCL:
1975                 tp->t_flags &= ~TF_EXCLUDE;
1976                 return (0);
1977         case TIOCSTOP:
1978                 tp->t_flags |= TF_STOPPED;
1979                 ttydevsw_pktnotify(tp, TIOCPKT_STOP);
1980                 return (0);
1981         case TIOCSTART:
1982                 tp->t_flags &= ~TF_STOPPED;
1983                 tp->t_termios.c_lflag &= ~FLUSHO;
1984                 ttydevsw_outwakeup(tp);
1985                 ttydevsw_pktnotify(tp, TIOCPKT_START);
1986                 return (0);
1987         case TIOCSTAT:
1988                 tty_info(tp);
1989                 return (0);
1990         case TIOCSTI:
1991                 if ((fflag & FREAD) == 0 && priv_check(td, PRIV_TTY_STI))
1992                         return (EPERM);
1993                 if (!tty_is_ctty(tp, td->td_proc) &&
1994                     priv_check(td, PRIV_TTY_STI))
1995                         return (EACCES);
1996                 ttydisc_rint(tp, *(char *)data, 0);
1997                 ttydisc_rint_done(tp);
1998                 return (0);
1999         }
2000
2001 #ifdef COMPAT_43TTY
2002         return tty_ioctl_compat(tp, cmd, data, fflag, td);
2003 #else /* !COMPAT_43TTY */
2004         return (ENOIOCTL);
2005 #endif /* COMPAT_43TTY */
2006 }
2007
2008 int
2009 tty_ioctl(struct tty *tp, u_long cmd, void *data, int fflag, struct thread *td)
2010 {
2011         int error;
2012
2013         tty_assert_locked(tp);
2014
2015         if (tty_gone(tp))
2016                 return (ENXIO);
2017
2018         error = ttydevsw_ioctl(tp, cmd, data, td);
2019         if (error == ENOIOCTL)
2020                 error = tty_generic_ioctl(tp, cmd, data, fflag, td);
2021
2022         return (error);
2023 }
2024
2025 dev_t
2026 tty_udev(struct tty *tp)
2027 {
2028
2029         if (tp->t_dev)
2030                 return (dev2udev(tp->t_dev));
2031         else
2032                 return (NODEV);
2033 }
2034
2035 int
2036 tty_checkoutq(struct tty *tp)
2037 {
2038
2039         /* 256 bytes should be enough to print a log message. */
2040         return (ttyoutq_bytesleft(&tp->t_outq) >= 256);
2041 }
2042
2043 void
2044 tty_hiwat_in_block(struct tty *tp)
2045 {
2046
2047         if ((tp->t_flags & TF_HIWAT_IN) == 0 &&
2048             tp->t_termios.c_iflag & IXOFF &&
2049             tp->t_termios.c_cc[VSTOP] != _POSIX_VDISABLE) {
2050                 /*
2051                  * Input flow control. Only enter the high watermark when we
2052                  * can successfully store the VSTOP character.
2053                  */
2054                 if (ttyoutq_write_nofrag(&tp->t_outq,
2055                     &tp->t_termios.c_cc[VSTOP], 1) == 0)
2056                         tp->t_flags |= TF_HIWAT_IN;
2057         } else {
2058                 /* No input flow control. */
2059                 tp->t_flags |= TF_HIWAT_IN;
2060         }
2061 }
2062
2063 void
2064 tty_hiwat_in_unblock(struct tty *tp)
2065 {
2066
2067         if (tp->t_flags & TF_HIWAT_IN &&
2068             tp->t_termios.c_iflag & IXOFF &&
2069             tp->t_termios.c_cc[VSTART] != _POSIX_VDISABLE) {
2070                 /*
2071                  * Input flow control. Only leave the high watermark when we
2072                  * can successfully store the VSTART character.
2073                  */
2074                 if (ttyoutq_write_nofrag(&tp->t_outq,
2075                     &tp->t_termios.c_cc[VSTART], 1) == 0)
2076                         tp->t_flags &= ~TF_HIWAT_IN;
2077         } else {
2078                 /* No input flow control. */
2079                 tp->t_flags &= ~TF_HIWAT_IN;
2080         }
2081
2082         if (!tty_gone(tp))
2083                 ttydevsw_inwakeup(tp);
2084 }
2085
2086 /*
2087  * TTY hooks interface.
2088  */
2089
2090 static int
2091 ttyhook_defrint(struct tty *tp, char c, int flags)
2092 {
2093
2094         if (ttyhook_rint_bypass(tp, &c, 1) != 1)
2095                 return (-1);
2096
2097         return (0);
2098 }
2099
2100 int
2101 ttyhook_register(struct tty **rtp, struct proc *p, int fd, struct ttyhook *th,
2102     void *softc)
2103 {
2104         struct tty *tp;
2105         struct file *fp;
2106         struct cdev *dev;
2107         struct cdevsw *cdp;
2108         struct filedesc *fdp;
2109         cap_rights_t rights;
2110         int error, ref;
2111
2112         /* Validate the file descriptor. */
2113         /*
2114          * XXX this code inspects a file descriptor from a different process,
2115          * but there is no dedicated routine to do it in fd code, making the
2116          * ordeal highly questionable.
2117          */
2118         fdp = p->p_fd;
2119         FILEDESC_SLOCK(fdp);
2120         error = fget_cap_noref(fdp, fd, cap_rights_init_one(&rights, CAP_TTYHOOK),
2121             &fp, NULL);
2122         if (error == 0 && !fhold(fp))
2123                 error = EBADF;
2124         FILEDESC_SUNLOCK(fdp);
2125         if (error != 0)
2126                 return (error);
2127         if (fp->f_ops == &badfileops) {
2128                 error = EBADF;
2129                 goto done1;
2130         }
2131
2132         /*
2133          * Make sure the vnode is bound to a character device.
2134          * Unlocked check for the vnode type is ok there, because we
2135          * only shall prevent calling devvn_refthread on the file that
2136          * never has been opened over a character device.
2137          */
2138         if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VCHR) {
2139                 error = EINVAL;
2140                 goto done1;
2141         }
2142
2143         /* Make sure it is a TTY. */
2144         cdp = devvn_refthread(fp->f_vnode, &dev, &ref);
2145         if (cdp == NULL) {
2146                 error = ENXIO;
2147                 goto done1;
2148         }
2149         if (dev != fp->f_data) {
2150                 error = ENXIO;
2151                 goto done2;
2152         }
2153         if (cdp != &ttydev_cdevsw) {
2154                 error = ENOTTY;
2155                 goto done2;
2156         }
2157         tp = dev->si_drv1;
2158
2159         /* Try to attach the hook to the TTY. */
2160         error = EBUSY;
2161         tty_lock(tp);
2162         MPASS((tp->t_hook == NULL) == ((tp->t_flags & TF_HOOK) == 0));
2163         if (tp->t_flags & TF_HOOK)
2164                 goto done3;
2165
2166         tp->t_flags |= TF_HOOK;
2167         tp->t_hook = th;
2168         tp->t_hooksoftc = softc;
2169         *rtp = tp;
2170         error = 0;
2171
2172         /* Maybe we can switch into bypass mode now. */
2173         ttydisc_optimize(tp);
2174
2175         /* Silently convert rint() calls to rint_bypass() when possible. */
2176         if (!ttyhook_hashook(tp, rint) && ttyhook_hashook(tp, rint_bypass))
2177                 th->th_rint = ttyhook_defrint;
2178
2179 done3:  tty_unlock(tp);
2180 done2:  dev_relthread(dev, ref);
2181 done1:  fdrop(fp, curthread);
2182         return (error);
2183 }
2184
2185 void
2186 ttyhook_unregister(struct tty *tp)
2187 {
2188
2189         tty_assert_locked(tp);
2190         MPASS(tp->t_flags & TF_HOOK);
2191
2192         /* Disconnect the hook. */
2193         tp->t_flags &= ~TF_HOOK;
2194         tp->t_hook = NULL;
2195
2196         /* Maybe we need to leave bypass mode. */
2197         ttydisc_optimize(tp);
2198
2199         /* Maybe deallocate the TTY as well. */
2200         tty_rel_free(tp);
2201 }
2202
2203 /*
2204  * /dev/console handling.
2205  */
2206
2207 static int
2208 ttyconsdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
2209 {
2210         struct tty *tp;
2211
2212         /* System has no console device. */
2213         if (dev_console_filename == NULL)
2214                 return (ENXIO);
2215
2216         /* Look up corresponding TTY by device name. */
2217         sx_slock(&tty_list_sx);
2218         TAILQ_FOREACH(tp, &tty_list, t_list) {
2219                 if (strcmp(dev_console_filename, tty_devname(tp)) == 0) {
2220                         dev_console->si_drv1 = tp;
2221                         break;
2222                 }
2223         }
2224         sx_sunlock(&tty_list_sx);
2225
2226         /* System console has no TTY associated. */
2227         if (dev_console->si_drv1 == NULL)
2228                 return (ENXIO);
2229
2230         return (ttydev_open(dev, oflags, devtype, td));
2231 }
2232
2233 static int
2234 ttyconsdev_write(struct cdev *dev, struct uio *uio, int ioflag)
2235 {
2236
2237         log_console(uio);
2238
2239         return (ttydev_write(dev, uio, ioflag));
2240 }
2241
2242 /*
2243  * /dev/console is a little different than normal TTY's.  When opened,
2244  * it determines which TTY to use.  When data gets written to it, it
2245  * will be logged in the kernel message buffer.
2246  */
2247 static struct cdevsw ttyconsdev_cdevsw = {
2248         .d_version      = D_VERSION,
2249         .d_open         = ttyconsdev_open,
2250         .d_close        = ttydev_close,
2251         .d_read         = ttydev_read,
2252         .d_write        = ttyconsdev_write,
2253         .d_ioctl        = ttydev_ioctl,
2254         .d_kqfilter     = ttydev_kqfilter,
2255         .d_poll         = ttydev_poll,
2256         .d_mmap         = ttydev_mmap,
2257         .d_name         = "ttyconsdev",
2258         .d_flags        = D_TTY,
2259 };
2260
2261 static void
2262 ttyconsdev_init(void *unused __unused)
2263 {
2264
2265         dev_console = make_dev_credf(MAKEDEV_ETERNAL, &ttyconsdev_cdevsw, 0,
2266             NULL, UID_ROOT, GID_WHEEL, 0600, "console");
2267 }
2268
2269 SYSINIT(tty, SI_SUB_DRIVERS, SI_ORDER_FIRST, ttyconsdev_init, NULL);
2270
2271 void
2272 ttyconsdev_select(const char *name)
2273 {
2274
2275         dev_console_filename = name;
2276 }
2277
2278 /*
2279  * Debugging routines.
2280  */
2281
2282 #include "opt_ddb.h"
2283 #ifdef DDB
2284 #include <ddb/ddb.h>
2285 #include <ddb/db_sym.h>
2286
2287 static const struct {
2288         int flag;
2289         char val;
2290 } ttystates[] = {
2291 #if 0
2292         { TF_NOPREFIX,          'N' },
2293 #endif
2294         { TF_INITLOCK,          'I' },
2295         { TF_CALLOUT,           'C' },
2296
2297         /* Keep these together -> 'Oi' and 'Oo'. */
2298         { TF_OPENED,            'O' },
2299         { TF_OPENED_IN,         'i' },
2300         { TF_OPENED_OUT,        'o' },
2301         { TF_OPENED_CONS,       'c' },
2302
2303         { TF_GONE,              'G' },
2304         { TF_OPENCLOSE,         'B' },
2305         { TF_ASYNC,             'Y' },
2306         { TF_LITERAL,           'L' },
2307
2308         /* Keep these together -> 'Hi' and 'Ho'. */
2309         { TF_HIWAT,             'H' },
2310         { TF_HIWAT_IN,          'i' },
2311         { TF_HIWAT_OUT,         'o' },
2312
2313         { TF_STOPPED,           'S' },
2314         { TF_EXCLUDE,           'X' },
2315         { TF_BYPASS,            'l' },
2316         { TF_ZOMBIE,            'Z' },
2317         { TF_HOOK,              's' },
2318
2319         /* Keep these together -> 'bi' and 'bo'. */
2320         { TF_BUSY,              'b' },
2321         { TF_BUSY_IN,           'i' },
2322         { TF_BUSY_OUT,          'o' },
2323
2324         { 0,                    '\0'},
2325 };
2326
2327 #define TTY_FLAG_BITS \
2328         "\20\1NOPREFIX\2INITLOCK\3CALLOUT\4OPENED_IN" \
2329         "\5OPENED_OUT\6OPENED_CONS\7GONE\10OPENCLOSE" \
2330         "\11ASYNC\12LITERAL\13HIWAT_IN\14HIWAT_OUT" \
2331         "\15STOPPED\16EXCLUDE\17BYPASS\20ZOMBIE" \
2332         "\21HOOK\22BUSY_IN\23BUSY_OUT"
2333
2334 #define DB_PRINTSYM(name, addr) \
2335         db_printf("%s  " #name ": ", sep); \
2336         db_printsym((db_addr_t) addr, DB_STGY_ANY); \
2337         db_printf("\n");
2338
2339 static void
2340 _db_show_devsw(const char *sep, const struct ttydevsw *tsw)
2341 {
2342
2343         db_printf("%sdevsw: ", sep);
2344         db_printsym((db_addr_t)tsw, DB_STGY_ANY);
2345         db_printf(" (%p)\n", tsw);
2346         DB_PRINTSYM(open, tsw->tsw_open);
2347         DB_PRINTSYM(close, tsw->tsw_close);
2348         DB_PRINTSYM(outwakeup, tsw->tsw_outwakeup);
2349         DB_PRINTSYM(inwakeup, tsw->tsw_inwakeup);
2350         DB_PRINTSYM(ioctl, tsw->tsw_ioctl);
2351         DB_PRINTSYM(param, tsw->tsw_param);
2352         DB_PRINTSYM(modem, tsw->tsw_modem);
2353         DB_PRINTSYM(mmap, tsw->tsw_mmap);
2354         DB_PRINTSYM(pktnotify, tsw->tsw_pktnotify);
2355         DB_PRINTSYM(free, tsw->tsw_free);
2356 }
2357
2358 static void
2359 _db_show_hooks(const char *sep, const struct ttyhook *th)
2360 {
2361
2362         db_printf("%shook: ", sep);
2363         db_printsym((db_addr_t)th, DB_STGY_ANY);
2364         db_printf(" (%p)\n", th);
2365         if (th == NULL)
2366                 return;
2367         DB_PRINTSYM(rint, th->th_rint);
2368         DB_PRINTSYM(rint_bypass, th->th_rint_bypass);
2369         DB_PRINTSYM(rint_done, th->th_rint_done);
2370         DB_PRINTSYM(rint_poll, th->th_rint_poll);
2371         DB_PRINTSYM(getc_inject, th->th_getc_inject);
2372         DB_PRINTSYM(getc_capture, th->th_getc_capture);
2373         DB_PRINTSYM(getc_poll, th->th_getc_poll);
2374         DB_PRINTSYM(close, th->th_close);
2375 }
2376
2377 static void
2378 _db_show_termios(const char *name, const struct termios *t)
2379 {
2380
2381         db_printf("%s: iflag 0x%x oflag 0x%x cflag 0x%x "
2382             "lflag 0x%x ispeed %u ospeed %u\n", name,
2383             t->c_iflag, t->c_oflag, t->c_cflag, t->c_lflag,
2384             t->c_ispeed, t->c_ospeed);
2385 }
2386
2387 /* DDB command to show TTY statistics. */
2388 DB_SHOW_COMMAND(tty, db_show_tty)
2389 {
2390         struct tty *tp;
2391
2392         if (!have_addr) {
2393                 db_printf("usage: show tty <addr>\n");
2394                 return;
2395         }
2396         tp = (struct tty *)addr;
2397
2398         db_printf("%p: %s\n", tp, tty_devname(tp));
2399         db_printf("\tmtx: %p\n", tp->t_mtx);
2400         db_printf("\tflags: 0x%b\n", tp->t_flags, TTY_FLAG_BITS);
2401         db_printf("\trevokecnt: %u\n", tp->t_revokecnt);
2402
2403         /* Buffering mechanisms. */
2404         db_printf("\tinq: %p begin %u linestart %u reprint %u end %u "
2405             "nblocks %u quota %u\n", &tp->t_inq, tp->t_inq.ti_begin,
2406             tp->t_inq.ti_linestart, tp->t_inq.ti_reprint, tp->t_inq.ti_end,
2407             tp->t_inq.ti_nblocks, tp->t_inq.ti_quota);
2408         db_printf("\toutq: %p begin %u end %u nblocks %u quota %u\n",
2409             &tp->t_outq, tp->t_outq.to_begin, tp->t_outq.to_end,
2410             tp->t_outq.to_nblocks, tp->t_outq.to_quota);
2411         db_printf("\tinlow: %zu\n", tp->t_inlow);
2412         db_printf("\toutlow: %zu\n", tp->t_outlow);
2413         _db_show_termios("\ttermios", &tp->t_termios);
2414         db_printf("\twinsize: row %u col %u xpixel %u ypixel %u\n",
2415             tp->t_winsize.ws_row, tp->t_winsize.ws_col,
2416             tp->t_winsize.ws_xpixel, tp->t_winsize.ws_ypixel);
2417         db_printf("\tcolumn: %u\n", tp->t_column);
2418         db_printf("\twritepos: %u\n", tp->t_writepos);
2419         db_printf("\tcompatflags: 0x%x\n", tp->t_compatflags);
2420
2421         /* Init/lock-state devices. */
2422         _db_show_termios("\ttermios_init_in", &tp->t_termios_init_in);
2423         _db_show_termios("\ttermios_init_out", &tp->t_termios_init_out);
2424         _db_show_termios("\ttermios_lock_in", &tp->t_termios_lock_in);
2425         _db_show_termios("\ttermios_lock_out", &tp->t_termios_lock_out);
2426
2427         /* Hooks */
2428         _db_show_devsw("\t", tp->t_devsw);
2429         _db_show_hooks("\t", tp->t_hook);
2430
2431         /* Process info. */
2432         db_printf("\tpgrp: %p gid %d\n", tp->t_pgrp,
2433             tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2434         db_printf("\tsession: %p", tp->t_session);
2435         if (tp->t_session != NULL)
2436             db_printf(" count %u leader %p tty %p sid %d login %s",
2437                 tp->t_session->s_count, tp->t_session->s_leader,
2438                 tp->t_session->s_ttyp, tp->t_session->s_sid,
2439                 tp->t_session->s_login);
2440         db_printf("\n");
2441         db_printf("\tsessioncnt: %u\n", tp->t_sessioncnt);
2442         db_printf("\tdevswsoftc: %p\n", tp->t_devswsoftc);
2443         db_printf("\thooksoftc: %p\n", tp->t_hooksoftc);
2444         db_printf("\tdev: %p\n", tp->t_dev);
2445 }
2446
2447 /* DDB command to list TTYs. */
2448 DB_SHOW_ALL_COMMAND(ttys, db_show_all_ttys)
2449 {
2450         struct tty *tp;
2451         size_t isiz, osiz;
2452         int i, j;
2453
2454         /* Make the output look like `pstat -t'. */
2455         db_printf("PTR        ");
2456 #if defined(__LP64__)
2457         db_printf("        ");
2458 #endif
2459         db_printf("      LINE   INQ  CAN  LIN  LOW  OUTQ  USE  LOW   "
2460             "COL  SESS  PGID STATE\n");
2461
2462         TAILQ_FOREACH(tp, &tty_list, t_list) {
2463                 isiz = tp->t_inq.ti_nblocks * TTYINQ_DATASIZE;
2464                 osiz = tp->t_outq.to_nblocks * TTYOUTQ_DATASIZE;
2465
2466                 db_printf("%p %10s %5zu %4u %4u %4zu %5zu %4u %4zu %5u %5d "
2467                     "%5d ", tp, tty_devname(tp), isiz,
2468                     tp->t_inq.ti_linestart - tp->t_inq.ti_begin,
2469                     tp->t_inq.ti_end - tp->t_inq.ti_linestart,
2470                     isiz - tp->t_inlow, osiz,
2471                     tp->t_outq.to_end - tp->t_outq.to_begin,
2472                     osiz - tp->t_outlow, MIN(tp->t_column, 99999),
2473                     tp->t_session ? tp->t_session->s_sid : 0,
2474                     tp->t_pgrp ? tp->t_pgrp->pg_id : 0);
2475
2476                 /* Flag bits. */
2477                 for (i = j = 0; ttystates[i].flag; i++)
2478                         if (tp->t_flags & ttystates[i].flag) {
2479                                 db_printf("%c", ttystates[i].val);
2480                                 j++;
2481                         }
2482                 if (j == 0)
2483                         db_printf("-");
2484                 db_printf("\n");
2485         }
2486 }
2487 #endif /* DDB */