sys/kern/tty_pty.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)tty_pty.c   8.4 (Berkeley) 2/20/95
  34  * $FreeBSD: src/sys/kern/tty_pty.c,v 1.74.2.4 2002/02/20 19:58:13 dillon Exp $
  35  * $DragonFly: src/sys/kern/tty_pty.c,v 1.21 2008/08/13 10:29:38 swildner Exp $
  36  */
  37
  38 /*
  39  * Pseudo-teletype Driver
  40  * (Actually two drivers, requiring two dev_ops structures)
  41  */
  42 #include "use_pty.h"            /* XXX */
  43 #include "opt_compat.h"
  44
  45 #include <sys/param.h>
  46 #include <sys/systm.h>
  47 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
  48 #include <sys/ioctl_compat.h>
  49 #endif
  50 #include <sys/proc.h>
  51 #include <sys/priv.h>
  52 #include <sys/tty.h>
  53 #include <sys/conf.h>
  54 #include <sys/fcntl.h>
  55 #include <sys/kernel.h>
  56 #include <sys/vnode.h>
  57 #include <sys/signalvar.h>
  58 #include <sys/malloc.h>
  59 #include <sys/device.h>
  60 #include <sys/thread2.h>
  61 #include <sys/devfs.h>
  62 #include <sys/stat.h>
  63 #include <sys/sysctl.h>
  64
  65 #define UNIX98_PTYS     1
  66
  67 MALLOC_DEFINE(M_PTY, "ptys", "pty data structures");
  68
  69 static void ptsstart (struct tty *tp);
  70 static void ptsstop (struct tty *tp, int rw);
  71 static void ptcwakeup (struct tty *tp, int flag);
  72 static void ptyinit (int n);
  73 static int  filt_ptcread (struct knote *kn, long hint);
  74 static void filt_ptcrdetach (struct knote *kn);
  75 static int  filt_ptcwrite (struct knote *kn, long hint);
  76 static void filt_ptcwdetach (struct knote *kn);
  77
  78 static  d_open_t        ptsopen;
  79 static  d_close_t       ptsclose;
  80 static  d_read_t        ptsread;
  81 static  d_write_t       ptswrite;
  82 static  d_ioctl_t       ptyioctl;
  83 static  d_open_t        ptcopen;
  84 static  d_close_t       ptcclose;
  85 static  d_read_t        ptcread;
  86 static  d_write_t       ptcwrite;
  87 static  d_kqfilter_t    ptckqfilter;
  88
  89 #ifdef UNIX98_PTYS
  90 DEVFS_DECLARE_CLONE_BITMAP(pty);
  91
  92 static  d_clone_t       ptyclone;
  93
  94 static int      pty_debug_level = 0;
  95
  96 static struct dev_ops pts98_ops = {
  97         { "pts98", 0, D_TTY | D_KQFILTER },
  98         .d_open =       ptsopen,
  99         .d_close =      ptsclose,
 100         .d_read =       ptsread,
 101         .d_write =      ptswrite,
 102         .d_ioctl =      ptyioctl,
 103         .d_kqfilter =   ttykqfilter,
 104         .d_revoke =     ttyrevoke
 105 };
 106
 107 static struct dev_ops ptc98_ops = {
 108         { "ptc98", 0, D_TTY | D_KQFILTER | D_MASTER },
 109         .d_open =       ptcopen,
 110         .d_close =      ptcclose,
 111         .d_read =       ptcread,
 112         .d_write =      ptcwrite,
 113         .d_ioctl =      ptyioctl,
 114         .d_kqfilter =   ptckqfilter,
 115         .d_revoke =     ttyrevoke
 116 };
 117 #endif
 118
 119 #define CDEV_MAJOR_S    5
 120 static struct dev_ops pts_ops = {
 121         { "pts", CDEV_MAJOR_S, D_TTY | D_KQFILTER },
 122         .d_open =       ptsopen,
 123         .d_close =      ptsclose,
 124         .d_read =       ptsread,
 125         .d_write =      ptswrite,
 126         .d_ioctl =      ptyioctl,
 127         .d_kqfilter =   ttykqfilter,
 128         .d_revoke =     ttyrevoke
 129 };
 130
 131 #define CDEV_MAJOR_C    6
 132 static struct dev_ops ptc_ops = {
 133         { "ptc", CDEV_MAJOR_C, D_TTY | D_KQFILTER | D_MASTER },
 134         .d_open =       ptcopen,
 135         .d_close =      ptcclose,
 136         .d_read =       ptcread,
 137         .d_write =      ptcwrite,
 138         .d_ioctl =      ptyioctl,
 139         .d_kqfilter =   ptckqfilter,
 140         .d_revoke =     ttyrevoke
 141 };
 142
 143 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
 144
 145 struct  pt_ioctl {
 146         int     pt_flags;
 147         int     pt_flags2;
 148         struct  selinfo pt_selr, pt_selw;
 149         u_char  pt_send;
 150         u_char  pt_ucntl;
 151         struct tty pt_tty;
 152         cdev_t  devs, devc;
 153         struct  prison *pt_prison;
 154 };
 155
 156 #define PF_PKT          0x08            /* packet mode */
 157 #define PF_STOPPED      0x10            /* user told stopped */
 158 #define PF_REMOTE       0x20            /* remote and flow controlled input */
 159 #define PF_NOSTOP       0x40
 160 #define PF_UCNTL        0x80            /* user control mode */
 161
 162 #define PF_UNIX98       0x01
 163 #define PF_SOPEN        0x02
 164 #define PF_MOPEN        0x04
 165
 166 static int
 167 ptydebug(int level, char *fmt, ...)
 168 {
 169         __va_list ap;
 170
 171         __va_start(ap, fmt);
 172         if (level <= pty_debug_level)
 173                 kvprintf(fmt, ap);
 174         __va_end(ap);
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * This function creates and initializes a pts/ptc pair
 181  *
 182  * pts == /dev/tty[pqrsPQRS][0123456789abcdefghijklmnopqrstuv]
 183  * ptc == /dev/pty[pqrsPQRS][0123456789abcdefghijklmnopqrstuv]
 184  *
 185  * XXX: define and add mapping of upper minor bits to allow more
 186  *      than 256 ptys.
 187  */
 188 static void
 189 ptyinit(int n)
 190 {
 191         cdev_t devs, devc;
 192         char *names = "pqrsPQRS";
 193         struct pt_ioctl *pt;
 194
 195         /* For now we only map the lower 8 bits of the minor */
 196         if (n & ~0xff)
 197                 return;
 198
 199         pt = kmalloc(sizeof(*pt), M_PTY, M_WAITOK | M_ZERO);
 200         pt->devs = devs = make_dev(&pts_ops, n,
 201             0, 0, 0666, "tty%c%r", names[n / 32], n % 32);
 202         pt->devc = devc = make_dev(&ptc_ops, n,
 203             0, 0, 0666, "pty%c%r", names[n / 32], n % 32);
 204
 205         devs->si_drv1 = devc->si_drv1 = pt;
 206         devs->si_tty = devc->si_tty = &pt->pt_tty;
 207         devs->si_flags |= SI_OVERRIDE;  /* uid, gid, perms from dev */
 208         devc->si_flags |= SI_OVERRIDE;  /* uid, gid, perms from dev */
 209         pt->pt_tty.t_dev = devs;
 210         ttyregister(&pt->pt_tty);
 211 }
 212
 213 #ifdef UNIX98_PTYS
 214 static int
 215 ptyclone(struct dev_clone_args *ap)
 216 {
 217         int unit;
 218         struct pt_ioctl *pt;
 219
 220         /*
 221          * Limit the number of unix98 pty (slave) devices to 1000, as
 222          * the utmp(5) format only allows for 8 bytes for the tty,
 223          * "pts/XXX".
 224          * If this limit is reached, we don't clone and return error
 225          * to devfs.
 226          */
 227         unit = devfs_clone_bitmap_get(&DEVFS_CLONE_BITMAP(pty), 1000);
 228
 229         if (unit < 0) {
 230                 ap->a_dev = NULL;
 231                 return 1;
 232         }
 233
 234         pt = kmalloc(sizeof(*pt), M_PTY, M_WAITOK | M_ZERO);
 235
 236         pt->devc = ap->a_dev = make_only_dev(&ptc98_ops, unit, ap->a_cred->cr_ruid,
 237             0, 0600, "ptm/%d", unit);
 238         pt->devs = make_dev(&pts98_ops, unit, ap->a_cred->cr_ruid, GID_TTY, 0620,
 239             "pts/%d", unit);
 240
 241         pt->devs->si_flags |= SI_OVERRIDE;      /* uid, gid, perms from dev */
 242         pt->devc->si_flags |= SI_OVERRIDE;      /* uid, gid, perms from dev */
 243
 244         pt->devs->si_drv1 = pt->devc->si_drv1 = pt;
 245         pt->devs->si_tty = pt->devc->si_tty = &pt->pt_tty;
 246         pt->pt_tty.t_dev = pt->devs;
 247         pt->pt_flags2 |= PF_UNIX98;
 248
 249         ttyregister(&pt->pt_tty);
 250
 251         return 0;
 252 }
 253 #endif
 254
 255 /*ARGSUSED*/
 256 static  int
 257 ptsopen(struct dev_open_args *ap)
 258 {
 259         cdev_t dev = ap->a_head.a_dev;
 260         struct tty *tp;
 261         int error;
 262         struct pt_ioctl *pti;
 263
 264         if (!dev->si_drv1)
 265                 ptyinit(minor(dev));
 266         if (!dev->si_drv1)
 267                 return(ENXIO);
 268         pti = dev->si_drv1;
 269         tp = dev->si_tty;
 270         if ((tp->t_state & TS_ISOPEN) == 0) {
 271                 ttychars(tp);           /* Set up default chars */
 272                 tp->t_iflag = TTYDEF_IFLAG;
 273                 tp->t_oflag = TTYDEF_OFLAG;
 274                 tp->t_lflag = TTYDEF_LFLAG;
 275                 tp->t_cflag = TTYDEF_CFLAG;
 276                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 277         } else if ((tp->t_state & TS_XCLUDE) && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
 278                 return (EBUSY);
 279         } else if (pti->pt_prison != ap->a_cred->cr_prison) {
 280                 return (EBUSY);
 281         }
 282         if (tp->t_oproc)                        /* Ctrlr still around. */
 283                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 284         while ((tp->t_state & TS_CARR_ON) == 0) {
 285                 if (ap->a_oflags & FNONBLOCK)
 286                         break;
 287                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "ptsopn", 0);
 288                 if (error)
 289                         return (error);
 290         }
 291         error = (*linesw[tp->t_line].l_open)(dev, tp);
 292         if (error == 0)
 293                 ptcwakeup(tp, FREAD|FWRITE);
 294
 295 #ifdef UNIX98_PTYS
 296         /*
 297          * Unix98 pty stuff.
 298          * On open of the slave, we set the corresponding flag in the common
 299          * struct.
 300          */
 301         ptydebug(1, "ptsopen=%s | unix98? %s\n", dev->si_name,
 302             (pti->pt_flags2 & PF_UNIX98)?"yes":"no");
 303
 304         if ((!error) && (pti->pt_flags2 & PF_UNIX98)) {
 305                 pti->pt_flags2 |= PF_SOPEN;
 306         }
 307 #endif
 308
 309         return (error);
 310 }
 311
 312 static  int
 313 ptsclose(struct dev_close_args *ap)
 314 {
 315         cdev_t dev = ap->a_head.a_dev;
 316         struct tty *tp;
 317         struct pt_ioctl *pti = dev->si_drv1;
 318         int err;
 319
 320         tp = dev->si_tty;
 321         err = (*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
 322         ptsstop(tp, FREAD|FWRITE);
 323         (void) ttyclose(tp);
 324
 325 #ifdef UNIX98_PTYS
 326         /*
 327          * Unix98 pty stuff.
 328          * On close of the slave, we unset the corresponding flag, and if the master
 329          * isn't open anymore, we destroy the slave and unset the unit.
 330          */
 331         ptydebug(1, "ptsclose=%s | unix98? %s\n", dev->si_name,
 332             (pti->pt_flags2 & PF_UNIX98)?"yes":"no");
 333
 334         if (pti->pt_flags2 & PF_UNIX98) {
 335                 pti->pt_flags2 &= ~PF_SOPEN;
 336                 KKASSERT((pti->pt_flags2 & PF_SOPEN) == 0);
 337                 ptydebug(1, "master open? %s\n",
 338                     (pti->pt_flags2 & PF_MOPEN)?"yes":"no");
 339
 340                 if (!(pti->pt_flags2 & PF_SOPEN) && !(pti->pt_flags2 & PF_MOPEN)) {
 341                         devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(pty), dev->si_uminor);
 342                         destroy_dev(dev);
 343                 }
 344         }
 345 #endif
 346
 347         return (err);
 348 }
 349
 350 static  int
 351 ptsread(struct dev_read_args *ap)
 352 {
 353         cdev_t dev = ap->a_head.a_dev;
 354         struct proc *p = curproc;
 355         struct tty *tp = dev->si_tty;
 356         struct pt_ioctl *pti = dev->si_drv1;
 357         struct lwp *lp;
 358
 359         int error = 0;
 360
 361         lp = curthread->td_lwp;
 362
 363 again:
 364         if (pti->pt_flags & PF_REMOTE) {
 365                 while (isbackground(p, tp)) {
 366                         if (SIGISMEMBER(p->p_sigignore, SIGTTIN) ||
 367                             SIGISMEMBER(lp->lwp_sigmask, SIGTTIN) ||
 368                             p->p_pgrp->pg_jobc == 0 || p->p_flag & P_PPWAIT)
 369                                 return (EIO);
 370                         pgsignal(p->p_pgrp, SIGTTIN, 1);
 371                         error = ttysleep(tp, &lbolt, PCATCH, "ptsbg", 0);
 372                         if (error)
 373                                 return (error);
 374                 }
 375                 if (tp->t_canq.c_cc == 0) {
 376                         if (ap->a_ioflag & IO_NDELAY)
 377                                 return (EWOULDBLOCK);
 378                         error = ttysleep(tp, TSA_PTS_READ(tp), PCATCH,
 379                                          "ptsin", 0);
 380                         if (error)
 381                                 return (error);
 382                         goto again;
 383                 }
 384                 while (tp->t_canq.c_cc > 1 && ap->a_uio->uio_resid > 0)
 385                         if (ureadc(clist_getc(&tp->t_canq), ap->a_uio) < 0) {
 386                                 error = EFAULT;
 387                                 break;
 388                         }
 389                 if (tp->t_canq.c_cc == 1)
 390                         clist_getc(&tp->t_canq);
 391                 if (tp->t_canq.c_cc)
 392                         return (error);
 393         } else
 394                 if (tp->t_oproc)
 395                         error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag);
 396         ptcwakeup(tp, FWRITE);
 397         return (error);
 398 }
 399
 400 /*
 401  * Write to pseudo-tty.
 402  * Wakeups of controlling tty will happen
 403  * indirectly, when tty driver calls ptsstart.
 404  */
 405 static  int
 406 ptswrite(struct dev_write_args *ap)
 407 {
 408         cdev_t dev = ap->a_head.a_dev;
 409         struct tty *tp;
 410
 411         tp = dev->si_tty;
 412         if (tp->t_oproc == 0)
 413                 return (EIO);
 414         return ((*linesw[tp->t_line].l_write)(tp, ap->a_uio, ap->a_ioflag));
 415 }
 416
 417 /*
 418  * Start output on pseudo-tty.
 419  * Wake up process selecting or sleeping for input from controlling tty.
 420  */
 421 static void
 422 ptsstart(struct tty *tp)
 423 {
 424         struct pt_ioctl *pti = tp->t_dev->si_drv1;
 425
 426         if (tp->t_state & TS_TTSTOP)
 427                 return;
 428         if (pti->pt_flags & PF_STOPPED) {
 429                 pti->pt_flags &= ~PF_STOPPED;
 430                 pti->pt_send = TIOCPKT_START;
 431         }
 432         ptcwakeup(tp, FREAD);
 433 }
 434
 435 static void
 436 ptcwakeup(struct tty *tp, int flag)
 437 {
 438         struct pt_ioctl *pti = tp->t_dev->si_drv1;
 439
 440         if (flag & FREAD) {
 441                 selwakeup(&pti->pt_selr);
 442                 wakeup(TSA_PTC_READ(tp));
 443                 KNOTE(&tp->t_rsel.si_note, 0);
 444         }
 445         if (flag & FWRITE) {
 446                 selwakeup(&pti->pt_selw);
 447                 wakeup(TSA_PTC_WRITE(tp));
 448                 KNOTE(&tp->t_wsel.si_note, 0);
 449         }
 450 }
 451
 452 static  int
 453 ptcopen(struct dev_open_args *ap)
 454 {
 455         cdev_t dev = ap->a_head.a_dev;
 456         struct tty *tp;
 457         struct pt_ioctl *pti;
 458
 459         if (!dev->si_drv1)
 460                 ptyinit(minor(dev));
 461         if (!dev->si_drv1)
 462                 return(ENXIO);
 463         pti = dev->si_drv1;
 464         if (pti->pt_prison && pti->pt_prison != ap->a_cred->cr_prison)
 465                 return(EBUSY);
 466         tp = dev->si_tty;
 467         if (tp->t_oproc)
 468                 return (EIO);
 469         tp->t_oproc = ptsstart;
 470         tp->t_stop = ptsstop;
 471         (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 472         tp->t_lflag &= ~EXTPROC;
 473         pti->pt_prison = ap->a_cred->cr_prison;
 474         pti->pt_flags = 0;
 475         pti->pt_send = 0;
 476         pti->pt_ucntl = 0;
 477
 478         pti->devs->si_uid = ap->a_cred->cr_uid;
 479         pti->devs->si_gid = 0;
 480         pti->devs->si_perms = 0600;
 481         pti->devc->si_uid = ap->a_cred->cr_uid;
 482         pti->devc->si_gid = 0;
 483         pti->devc->si_perms = 0600;
 484
 485 #ifdef UNIX98_PTYS
 486         /*
 487          * Unix98 pty stuff.
 488          * On open of the master, we set the corresponding flag in the common
 489          * struct.
 490          */
 491         ptydebug(1, "ptcopen=%s (master) | unix98? %s\n", dev->si_name,
 492             (pti->pt_flags2 & PF_UNIX98)?"yes":"no");
 493
 494         if (pti->pt_flags2 & PF_UNIX98) {
 495                 pti->pt_flags2 |= PF_MOPEN;
 496         }
 497 #endif
 498
 499         return (0);
 500 }
 501
 502 static  int
 503 ptcclose(struct dev_close_args *ap)
 504 {
 505         cdev_t dev = ap->a_head.a_dev;
 506         struct tty *tp;
 507         struct pt_ioctl *pti = dev->si_drv1;
 508
 509         tp = dev->si_tty;
 510         (void)(*linesw[tp->t_line].l_modem)(tp, 0);
 511
 512 #ifdef UNIX98_PTYS
 513         /*
 514          * Unix98 pty stuff.
 515          * On close of the master, we unset the corresponding flag in the common
 516          * struct asap.
 517          */
 518         pti->pt_flags2 &= ~PF_MOPEN;
 519 #endif
 520
 521         /*
 522          * XXX MDMBUF makes no sense for ptys but would inhibit the above
 523          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 524          * l_modem()s that ignore carrier drop make no sense for ptys but
 525          * may be in use because other parts of the line discipline make
 526          * sense for ptys.  Recover by doing everything that a normal
 527          * ttymodem() would have done except for sending a SIGHUP.
 528          */
 529         if (tp->t_state & TS_ISOPEN) {
 530                 tp->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 531                 tp->t_state |= TS_ZOMBIE;
 532                 ttyflush(tp, FREAD | FWRITE);
 533         }
 534         tp->t_oproc = 0;                /* mark closed */
 535
 536         pti = dev->si_drv1;
 537         pti->pt_prison = NULL;
 538         pti->devs->si_uid = 0;
 539         pti->devs->si_gid = 0;
 540         pti->devs->si_perms = 0666;
 541         pti->devc->si_uid = 0;
 542         pti->devc->si_gid = 0;
 543         pti->devc->si_perms = 0666;
 544
 545 #ifdef UNIX98_PTYS
 546         /*
 547          * Unix98 pty stuff.
 548          * On close of the master, we destroy the master and, if no slaves are open,
 549          * we destroy the slave device and unset the unit.
 550          */
 551         ptydebug(1, "ptcclose=%s (master) | unix98? %s\n", dev->si_name,
 552             (pti->pt_flags2 & PF_UNIX98)?"yes":"no");
 553         if (pti->pt_flags2 & PF_UNIX98) {
 554                 KKASSERT((pti->pt_flags2 & PF_MOPEN) == 0);
 555                 destroy_dev(dev);
 556                 pti->devc = NULL;
 557
 558                 if (!(pti->pt_flags2 & PF_SOPEN)) {
 559                         ptydebug(1, "ptcclose: slaves are not open\n");
 560                         destroy_dev(pti->devs);
 561                         devfs_clone_bitmap_put(&DEVFS_CLONE_BITMAP(pty), dev->si_uminor);
 562                 }
 563         }
 564 #endif
 565
 566         return (0);
 567 }
 568
 569 static  int
 570 ptcread(struct dev_read_args *ap)
 571 {
 572         cdev_t dev = ap->a_head.a_dev;
 573         struct tty *tp = dev->si_tty;
 574         struct pt_ioctl *pti = dev->si_drv1;
 575         char buf[BUFSIZ];
 576         int error = 0, cc;
 577
 578         /*
 579          * We want to block until the slave
 580          * is open, and there's something to read;
 581          * but if we lost the slave or we're NBIO,
 582          * then return the appropriate error instead.
 583          */
 584         for (;;) {
 585                 if (tp->t_state&TS_ISOPEN) {
 586                         if (pti->pt_flags&PF_PKT && pti->pt_send) {
 587                                 error = ureadc((int)pti->pt_send, ap->a_uio);
 588                                 if (error)
 589                                         return (error);
 590                                 if (pti->pt_send & TIOCPKT_IOCTL) {
 591                                         cc = (int)szmin(ap->a_uio->uio_resid,
 592                                                         sizeof(tp->t_termios));
 593                                         uiomove((caddr_t)&tp->t_termios, cc,
 594                                                 ap->a_uio);
 595                                 }
 596                                 pti->pt_send = 0;
 597                                 return (0);
 598                         }
 599                         if (pti->pt_flags&PF_UCNTL && pti->pt_ucntl) {
 600                                 error = ureadc((int)pti->pt_ucntl, ap->a_uio);
 601                                 if (error)
 602                                         return (error);
 603                                 pti->pt_ucntl = 0;
 604                                 return (0);
 605                         }
 606                         if (tp->t_outq.c_cc && (tp->t_state&TS_TTSTOP) == 0)
 607                                 break;
 608                 }
 609                 if ((tp->t_state & TS_CONNECTED) == 0)
 610                         return (0);     /* EOF */
 611                 if (ap->a_ioflag & IO_NDELAY)
 612                         return (EWOULDBLOCK);
 613                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "ptcin", 0);
 614                 if (error)
 615                         return (error);
 616         }
 617         if (pti->pt_flags & (PF_PKT|PF_UCNTL))
 618                 error = ureadc(0, ap->a_uio);
 619         while (ap->a_uio->uio_resid > 0 && error == 0) {
 620                 cc = q_to_b(&tp->t_outq, buf,
 621                             (int)szmin(ap->a_uio->uio_resid, BUFSIZ));
 622                 if (cc <= 0)
 623                         break;
 624                 error = uiomove(buf, (size_t)cc, ap->a_uio);
 625         }
 626         ttwwakeup(tp);
 627         return (error);
 628 }
 629
 630 static  void
 631 ptsstop(struct tty *tp, int flush)
 632 {
 633         struct pt_ioctl *pti = tp->t_dev->si_drv1;
 634         int flag;
 635
 636         /* note: FLUSHREAD and FLUSHWRITE already ok */
 637         if (flush == 0) {
 638                 flush = TIOCPKT_STOP;
 639                 pti->pt_flags |= PF_STOPPED;
 640         } else
 641                 pti->pt_flags &= ~PF_STOPPED;
 642         pti->pt_send |= flush;
 643         /* change of perspective */
 644         flag = 0;
 645         if (flush & FREAD)
 646                 flag |= FWRITE;
 647         if (flush & FWRITE)
 648                 flag |= FREAD;
 649         ptcwakeup(tp, flag);
 650 }
 651
 652 /*
 653  * kqueue ops for pseudo-terminals.
 654  */
 655 static struct filterops ptcread_filtops =
 656         { 1, NULL, filt_ptcrdetach, filt_ptcread };
 657 static struct filterops ptcwrite_filtops =
 658         { 1, NULL, filt_ptcwdetach, filt_ptcwrite };
 659
 660 static  int
 661 ptckqfilter(struct dev_kqfilter_args *ap)
 662 {
 663         cdev_t dev = ap->a_head.a_dev;
 664         struct knote *kn = ap->a_kn;
 665         struct tty *tp = dev->si_tty;
 666         struct klist *klist;
 667
 668         ap->a_result = 0;
 669         switch (kn->kn_filter) {
 670         case EVFILT_READ:
 671                 klist = &tp->t_rsel.si_note;
 672                 kn->kn_fop = &ptcread_filtops;
 673                 break;
 674         case EVFILT_WRITE:
 675                 klist = &tp->t_wsel.si_note;
 676                 kn->kn_fop = &ptcwrite_filtops;
 677                 break;
 678         default:
 679                 ap->a_result = EOPNOTSUPP;
 680                 return (0);
 681         }
 682
 683         kn->kn_hook = (caddr_t)dev;
 684
 685         crit_enter();
 686         SLIST_INSERT_HEAD(klist, kn, kn_selnext);
 687         crit_exit();
 688
 689         return (0);
 690 }
 691
 692 static int
 693 filt_ptcread (struct knote *kn, long hint)
 694 {
 695         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
 696         struct pt_ioctl *pti = ((cdev_t)kn->kn_hook)->si_drv1;
 697
 698         if ((tp->t_state & TS_ISOPEN) &&
 699             ((tp->t_outq.c_cc && (tp->t_state & TS_TTSTOP) == 0) ||
 700              ((pti->pt_flags & PF_PKT) && pti->pt_send) ||
 701              ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))) {
 702                 kn->kn_data = tp->t_outq.c_cc;
 703                 return(1);
 704         } else {
 705                 return(0);
 706         }
 707 }
 708
 709 static int
 710 filt_ptcwrite (struct knote *kn, long hint)
 711 {
 712         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
 713         struct pt_ioctl *pti = ((cdev_t)kn->kn_hook)->si_drv1;
 714
 715         if (tp->t_state & TS_ISOPEN &&
 716             ((pti->pt_flags & PF_REMOTE) ?
 717              (tp->t_canq.c_cc == 0) :
 718              ((tp->t_rawq.c_cc + tp->t_canq.c_cc < TTYHOG - 2) ||
 719               (tp->t_canq.c_cc == 0 && (tp->t_lflag & ICANON))))) {
 720                 kn->kn_data = tp->t_canq.c_cc + tp->t_rawq.c_cc;
 721                 return(1);
 722         } else {
 723                 return(0);
 724         }
 725 }
 726
 727 static void
 728 filt_ptcrdetach (struct knote *kn)
 729 {
 730         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
 731
 732         crit_enter();
 733         SLIST_REMOVE(&tp->t_rsel.si_note, kn, knote, kn_selnext);
 734         crit_exit();
 735 }
 736
 737 static void
 738 filt_ptcwdetach (struct knote *kn)
 739 {
 740         struct tty *tp = ((cdev_t)kn->kn_hook)->si_tty;
 741
 742         crit_enter();
 743         SLIST_REMOVE(&tp->t_wsel.si_note, kn, knote, kn_selnext);
 744         crit_exit();
 745 }
 746
 747 /*
 748  * I/O ops
 749  */
 750 static  int
 751 ptcwrite(struct dev_write_args *ap)
 752 {
 753         cdev_t dev = ap->a_head.a_dev;
 754         struct tty *tp = dev->si_tty;
 755         u_char *cp = 0;
 756         int cc = 0;
 757         u_char locbuf[BUFSIZ];
 758         int cnt = 0;
 759         struct pt_ioctl *pti = dev->si_drv1;
 760         int error = 0;
 761
 762 again:
 763         if ((tp->t_state&TS_ISOPEN) == 0)
 764                 goto block;
 765         if (pti->pt_flags & PF_REMOTE) {
 766                 if (tp->t_canq.c_cc)
 767                         goto block;
 768                 while ((ap->a_uio->uio_resid > 0 || cc > 0) &&
 769                        tp->t_canq.c_cc < TTYHOG - 1) {
 770                         if (cc == 0) {
 771                                 cc = (int)szmin(ap->a_uio->uio_resid, BUFSIZ);
 772                                 cc = imin(cc, TTYHOG - 1 - tp->t_canq.c_cc);
 773                                 cp = locbuf;
 774                                 error = uiomove(cp, (size_t)cc, ap->a_uio);
 775                                 if (error)
 776                                         return (error);
 777                                 /* check again for safety */
 778                                 if ((tp->t_state & TS_ISOPEN) == 0) {
 779                                         /* adjust as usual */
 780                                         ap->a_uio->uio_resid += cc;
 781                                         return (EIO);
 782                                 }
 783                         }
 784                         if (cc > 0) {
 785                                 cc = b_to_q((char *)cp, cc, &tp->t_canq);
 786                                 /*
 787                                  * XXX we don't guarantee that the canq size
 788                                  * is >= TTYHOG, so the above b_to_q() may
 789                                  * leave some bytes uncopied.  However, space
 790                                  * is guaranteed for the null terminator if
 791                                  * we don't fail here since (TTYHOG - 1) is
 792                                  * not a multiple of CBSIZE.
 793                                  */
 794                                 if (cc > 0)
 795                                         break;
 796                         }
 797                 }
 798                 /* adjust for data copied in but not written */
 799                 ap->a_uio->uio_resid += cc;
 800                 clist_putc(0, &tp->t_canq);
 801                 ttwakeup(tp);
 802                 wakeup(TSA_PTS_READ(tp));
 803                 return (0);
 804         }
 805         while (ap->a_uio->uio_resid > 0 || cc > 0) {
 806                 if (cc == 0) {
 807                         cc = (int)szmin(ap->a_uio->uio_resid, BUFSIZ);
 808                         cp = locbuf;
 809                         error = uiomove(cp, (size_t)cc, ap->a_uio);
 810                         if (error)
 811                                 return (error);
 812                         /* check again for safety */
 813                         if ((tp->t_state & TS_ISOPEN) == 0) {
 814                                 /* adjust for data copied in but not written */
 815                                 ap->a_uio->uio_resid += cc;
 816                                 return (EIO);
 817                         }
 818                 }
 819                 while (cc > 0) {
 820                         if ((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= TTYHOG - 2 &&
 821                            (tp->t_canq.c_cc > 0 || !(tp->t_lflag&ICANON))) {
 822                                 wakeup(TSA_HUP_OR_INPUT(tp));
 823                                 goto block;
 824                         }
 825                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 826                         cnt++;
 827                         cc--;
 828                 }
 829                 cc = 0;
 830         }
 831         return (0);
 832 block:
 833         /*
 834          * Come here to wait for slave to open, for space
 835          * in outq, or space in rawq, or an empty canq.
 836          */
 837         if ((tp->t_state & TS_CONNECTED) == 0) {
 838                 /* adjust for data copied in but not written */
 839                 ap->a_uio->uio_resid += cc;
 840                 return (EIO);
 841         }
 842         if (ap->a_ioflag & IO_NDELAY) {
 843                 /* adjust for data copied in but not written */
 844                 ap->a_uio->uio_resid += cc;
 845                 if (cnt == 0)
 846                         return (EWOULDBLOCK);
 847                 return (0);
 848         }
 849         error = tsleep(TSA_PTC_WRITE(tp), PCATCH, "ptcout", 0);
 850         if (error) {
 851                 /* adjust for data copied in but not written */
 852                 ap->a_uio->uio_resid += cc;
 853                 return (error);
 854         }
 855         goto again;
 856 }
 857
 858 /*ARGSUSED*/
 859 static  int
 860 ptyioctl(struct dev_ioctl_args *ap)
 861 {
 862         cdev_t dev = ap->a_head.a_dev;
 863         struct tty *tp = dev->si_tty;
 864         struct pt_ioctl *pti = dev->si_drv1;
 865         u_char *cc = tp->t_cc;
 866         int stop, error;
 867
 868         if (dev_dflags(dev) & D_MASTER) {
 869                 switch (ap->a_cmd) {
 870
 871                 case TIOCGPGRP:
 872                         /*
 873                          * We avoid calling ttioctl on the controller since,
 874                          * in that case, tp must be the controlling terminal.
 875                          */
 876                         *(int *)ap->a_data = tp->t_pgrp ? tp->t_pgrp->pg_id : 0;
 877                         return (0);
 878
 879                 case TIOCPKT:
 880                         if (*(int *)ap->a_data) {
 881                                 if (pti->pt_flags & PF_UCNTL)
 882                                         return (EINVAL);
 883                                 pti->pt_flags |= PF_PKT;
 884                         } else
 885                                 pti->pt_flags &= ~PF_PKT;
 886                         return (0);
 887
 888                 case TIOCUCNTL:
 889                         if (*(int *)ap->a_data) {
 890                                 if (pti->pt_flags & PF_PKT)
 891                                         return (EINVAL);
 892                                 pti->pt_flags |= PF_UCNTL;
 893                         } else
 894                                 pti->pt_flags &= ~PF_UCNTL;
 895                         return (0);
 896
 897                 case TIOCREMOTE:
 898                         if (*(int *)ap->a_data)
 899                                 pti->pt_flags |= PF_REMOTE;
 900                         else
 901                                 pti->pt_flags &= ~PF_REMOTE;
 902                         ttyflush(tp, FREAD|FWRITE);
 903                         return (0);
 904
 905                 case TIOCISPTMASTER:
 906                         if ((pti->pt_flags2 & PF_UNIX98) && (pti->devc == dev))
 907                                 return (0);
 908                         else
 909                                 return (EINVAL);
 910                 }
 911
 912                 /*
 913                  * The rest of the ioctls shouldn't be called until
 914                  * the slave is open.
 915                  */
 916                 if ((tp->t_state & TS_ISOPEN) == 0)
 917                         return (EAGAIN);
 918
 919                 switch (ap->a_cmd) {
 920 #ifdef COMPAT_43
 921                 case TIOCSETP:
 922                 case TIOCSETN:
 923 #endif
 924                 case TIOCSETD:
 925                 case TIOCSETA:
 926                 case TIOCSETAW:
 927                 case TIOCSETAF:
 928                         /*
 929                          * IF CONTROLLER STTY THEN MUST FLUSH TO PREVENT A HANG.
 930                          * ttywflush(tp) will hang if there are characters in
 931                          * the outq.
 932                          */
 933                         ndflush(&tp->t_outq, tp->t_outq.c_cc);
 934                         break;
 935
 936                 case TIOCSIG:
 937                         if (*(unsigned int *)ap->a_data >= NSIG ||
 938                             *(unsigned int *)ap->a_data == 0)
 939                                 return(EINVAL);
 940                         if ((tp->t_lflag&NOFLSH) == 0)
 941                                 ttyflush(tp, FREAD|FWRITE);
 942                         pgsignal(tp->t_pgrp, *(unsigned int *)ap->a_data, 1);
 943                         if ((*(unsigned int *)ap->a_data == SIGINFO) &&
 944                             ((tp->t_lflag&NOKERNINFO) == 0))
 945                                 ttyinfo(tp);
 946                         return(0);
 947                 }
 948         }
 949         if (ap->a_cmd == TIOCEXT) {
 950                 /*
 951                  * When the EXTPROC bit is being toggled, we need
 952                  * to send an TIOCPKT_IOCTL if the packet driver
 953                  * is turned on.
 954                  */
 955                 if (*(int *)ap->a_data) {
 956                         if (pti->pt_flags & PF_PKT) {
 957                                 pti->pt_send |= TIOCPKT_IOCTL;
 958                                 ptcwakeup(tp, FREAD);
 959                         }
 960                         tp->t_lflag |= EXTPROC;
 961                 } else {
 962                         if ((tp->t_lflag & EXTPROC) &&
 963                             (pti->pt_flags & PF_PKT)) {
 964                                 pti->pt_send |= TIOCPKT_IOCTL;
 965                                 ptcwakeup(tp, FREAD);
 966                         }
 967                         tp->t_lflag &= ~EXTPROC;
 968                 }
 969                 return(0);
 970         }
 971         error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
 972                                               ap->a_fflag, ap->a_cred);
 973         if (error == ENOIOCTL)
 974                  error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
 975         if (error == ENOIOCTL) {
 976                 if (pti->pt_flags & PF_UCNTL &&
 977                     (ap->a_cmd & ~0xff) == UIOCCMD(0)) {
 978                         if (ap->a_cmd & 0xff) {
 979                                 pti->pt_ucntl = (u_char)ap->a_cmd;
 980                                 ptcwakeup(tp, FREAD);
 981                         }
 982                         return (0);
 983                 }
 984                 error = ENOTTY;
 985         }
 986         /*
 987          * If external processing and packet mode send ioctl packet.
 988          */
 989         if ((tp->t_lflag&EXTPROC) && (pti->pt_flags & PF_PKT)) {
 990                 switch(ap->a_cmd) {
 991                 case TIOCSETA:
 992                 case TIOCSETAW:
 993                 case TIOCSETAF:
 994 #ifdef COMPAT_43
 995                 case TIOCSETP:
 996                 case TIOCSETN:
 997 #endif
 998 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
 999                 case TIOCSETC:
1000                 case TIOCSLTC:
1001                 case TIOCLBIS:
1002                 case TIOCLBIC:
1003                 case TIOCLSET:
1004 #endif
1005                         pti->pt_send |= TIOCPKT_IOCTL;
1006                         ptcwakeup(tp, FREAD);
1007                 default:
1008                         break;
1009                 }
1010         }
1011         stop = (tp->t_iflag & IXON) && CCEQ(cc[VSTOP], CTRL('s'))
1012                 && CCEQ(cc[VSTART], CTRL('q'));
1013         if (pti->pt_flags & PF_NOSTOP) {
1014                 if (stop) {
1015                         pti->pt_send &= ~TIOCPKT_NOSTOP;
1016                         pti->pt_send |= TIOCPKT_DOSTOP;
1017                         pti->pt_flags &= ~PF_NOSTOP;
1018                         ptcwakeup(tp, FREAD);
1019                 }
1020         } else {
1021                 if (!stop) {
1022                         pti->pt_send &= ~TIOCPKT_DOSTOP;
1023                         pti->pt_send |= TIOCPKT_NOSTOP;
1024                         pti->pt_flags |= PF_NOSTOP;
1025                         ptcwakeup(tp, FREAD);
1026                 }
1027         }
1028         return (error);
1029 }
1030
1031
1032 static void ptc_drvinit (void *unused);
1033
1034 #ifdef UNIX98_PTYS
1035 SYSCTL_INT(_kern, OID_AUTO, pty_debug, CTLFLAG_RW, &pty_debug_level,
1036                 0, "Change pty debug level");
1037 #endif
1038
1039 static void
1040 ptc_drvinit(void *unused)
1041 {
1042         int i;
1043
1044 #ifdef UNIX98_PTYS
1045         /*
1046          * Unix98 pty stuff.
1047          * Create the clonable base device.
1048          */
1049         make_autoclone_dev(&ptc_ops, &DEVFS_CLONE_BITMAP(pty), ptyclone,
1050             0, 0, 0666, "ptmx");
1051 #endif
1052
1053         for (i = 0; i < 256; i++) {
1054                 ptyinit(i);
1055         }
1056 }
1057
1058 SYSINIT(ptcdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR_C,ptc_drvinit,NULL)