sys/dev/misc/nmdm/nmdm.c

   1 /*
   2  * (MPSAFE)
   3  *
   4  * Copyright (c) 1982, 1986, 1989, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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  * $FreeBSD: src/sys/dev/nmdm/nmdm.c,v 1.5.2.1 2001/08/11 00:54:14 mp Exp $
  32  */
  33
  34 /*
  35  * MPSAFE NOTE: This file acquires the tty_token mainly for linesw access and
  36  *              tp (struct tty) access.
  37  */
  38
  39 /*
  40  * Pseudo-nulmodem Driver
  41  */
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/proc.h>
  45 #include <sys/priv.h>
  46 #include <sys/thread2.h>
  47 #include <sys/tty.h>
  48 #include <sys/conf.h>
  49 #include <sys/fcntl.h>
  50 #include <sys/kernel.h>
  51 #include <sys/vnode.h>
  52 #include <sys/signalvar.h>
  53 #include <sys/malloc.h>
  54
  55 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
  56
  57 static void nmdmstart (struct tty *tp);
  58 static void nmdmstop (struct tty *tp, int rw);
  59 static void wakeup_other (struct tty *tp, int flag);
  60 static void nmdminit (int n);
  61
  62 static  d_open_t        nmdmopen;
  63 static  d_close_t       nmdmclose;
  64 static  d_read_t        nmdmread;
  65 static  d_write_t       nmdmwrite;
  66 static  d_ioctl_t       nmdmioctl;
  67
  68 #define CDEV_MAJOR      18
  69 static struct dev_ops nmdm_ops = {
  70         { "pts", 0, D_TTY },
  71         .d_open =       nmdmopen,
  72         .d_close =      nmdmclose,
  73         .d_read =       nmdmread,
  74         .d_write =      nmdmwrite,
  75         .d_ioctl =      nmdmioctl,
  76         .d_kqfilter =   ttykqfilter,
  77         .d_revoke =     ttyrevoke
  78 };
  79
  80 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
  81
  82 struct softpart {
  83         struct tty nm_tty;
  84         cdev_t  dev;
  85         int     modemsignals;   /* bits defined in sys/ttycom.h */
  86         int     gotbreak;
  87 };
  88
  89 struct  nm_softc {
  90         int     pt_flags;
  91         struct softpart part1, part2;
  92         struct  prison *pt_prison;
  93 };
  94
  95 #define PF_STOPPED      0x10            /* user told stopped */
  96
  97 static void
  98 nmdm_crossover(struct nm_softc *pti,
  99                 struct softpart *ourpart,
 100                 struct softpart *otherpart);
 101
 102 #define GETPARTS(tp, ourpart, otherpart) \
 103 do {    \
 104         struct nm_softc *pti = tp->t_dev->si_drv1; \
 105         if (tp == &pti->part1.nm_tty) { \
 106                 ourpart = &pti->part1; \
 107                 otherpart = &pti->part2; \
 108         } else { \
 109                 ourpart = &pti->part2; \
 110                 otherpart = &pti->part1; \
 111         }  \
 112 } while (0)
 113
 114 /*
 115  * This function creates and initializes a pair of ttys.
 116  *
 117  * NOTE: Must be called with tty_token held
 118  */
 119 static void
 120 nmdminit(int n)
 121 {
 122         cdev_t dev1, dev2;
 123         struct nm_softc *pt;
 124
 125         /*
 126          * Simplified unit number, use low 8 bits of minor number
 127          * (remember, the minor number mask is 0xffff00ff).
 128          */
 129         if (n & ~0x7f)
 130                 return;
 131
 132         ASSERT_LWKT_TOKEN_HELD(&tty_token);
 133
 134         pt = kmalloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
 135         pt->part1.dev = dev1 = make_dev(&nmdm_ops, n << 1,
 136                                         0, 0, 0666, "nmdm%dA", n);
 137         pt->part2.dev = dev2 = make_dev(&nmdm_ops, (n << 1) + 1,
 138                                         0, 0, 0666, "nmdm%dB", n);
 139
 140         dev1->si_drv1 = dev2->si_drv1 = pt;
 141         dev1->si_tty = &pt->part1.nm_tty;
 142         dev2->si_tty = &pt->part2.nm_tty;
 143         ttyregister(&pt->part1.nm_tty);
 144         ttyregister(&pt->part2.nm_tty);
 145         pt->part1.nm_tty.t_oproc = nmdmstart;
 146         pt->part2.nm_tty.t_oproc = nmdmstart;
 147         pt->part1.nm_tty.t_stop = nmdmstop;
 148         pt->part2.nm_tty.t_dev = dev1;
 149         pt->part1.nm_tty.t_dev = dev2;
 150         pt->part2.nm_tty.t_stop = nmdmstop;
 151 }
 152
 153 /*ARGSUSED*/
 154 static  int
 155 nmdmopen(struct dev_open_args *ap)
 156 {
 157         cdev_t dev = ap->a_head.a_dev;
 158         struct tty *tp, *tp2;
 159         int error;
 160         int minr;
 161 #if 0
 162         cdev_t nextdev;
 163 #endif
 164         struct nm_softc *pti;
 165         int is_b;
 166         int     pair;
 167         struct  softpart *ourpart, *otherpart;
 168
 169         minr = lminor(dev);
 170         pair = minr >> 1;
 171         is_b = minr & 1;
 172
 173 #if 0
 174         /*
 175          * XXX: Gross hack for DEVFS:
 176          * If we openned this device, ensure we have the
 177          * next one too, so people can open it.
 178          */
 179         if (pair < 127) {
 180                 nextdev = makedev(major(dev), (pair+pair) + 1);
 181                 if (!nextdev->si_drv1) {
 182                         nmdminit(pair + 1);
 183                 }
 184         }
 185 #endif
 186         if (!dev->si_drv1)
 187                 nmdminit(pair);
 188
 189         if (!dev->si_drv1)
 190                 return(ENXIO);
 191
 192         lwkt_gettoken(&tty_token);
 193         pti = dev->si_drv1;
 194         if (is_b)
 195                 tp = &pti->part2.nm_tty;
 196         else
 197                 tp = &pti->part1.nm_tty;
 198         GETPARTS(tp, ourpart, otherpart);
 199         tp2 = &otherpart->nm_tty;
 200         ourpart->modemsignals |= TIOCM_LE;
 201
 202         if ((tp->t_state & TS_ISOPEN) == 0) {
 203                 ttychars(tp);           /* Set up default chars */
 204                 tp->t_iflag = TTYDEF_IFLAG;
 205                 tp->t_oflag = TTYDEF_OFLAG;
 206                 tp->t_lflag = TTYDEF_LFLAG;
 207                 tp->t_cflag = TTYDEF_CFLAG;
 208                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 209         } else if (tp->t_state & TS_XCLUDE && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
 210                 lwkt_reltoken(&tty_token);
 211                 return (EBUSY);
 212         } else if (pti->pt_prison != ap->a_cred->cr_prison) {
 213                 lwkt_reltoken(&tty_token);
 214                 return (EBUSY);
 215         }
 216
 217         /*
 218          * If the other side is open we have carrier
 219          */
 220         if (tp2->t_state & TS_ISOPEN) {
 221                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 222         }
 223
 224         /*
 225          * And the other side gets carrier as we are now open.
 226          */
 227         (void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
 228
 229         /* External processing makes no sense here */
 230         tp->t_lflag &= ~EXTPROC;
 231
 232         /*
 233          * Wait here if we don't have carrier.
 234          */
 235 #if 0
 236         while ((tp->t_state & TS_CARR_ON) == 0) {
 237                 if (flag & FNONBLOCK)
 238                         break;
 239                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
 240                 if (error) {
 241                         lwkt_reltoken(&tty_token);
 242                         return (error);
 243                 }
 244         }
 245 #endif
 246
 247         /*
 248          * Give the line disciplin a chance to set this end up.
 249          */
 250         error = (*linesw[tp->t_line].l_open)(dev, tp);
 251
 252         /*
 253          * Wake up the other side.
 254          * Theoretically not needed.
 255          */
 256         ourpart->modemsignals |= TIOCM_DTR;
 257         nmdm_crossover(pti, ourpart, otherpart);
 258         if (error == 0)
 259                 wakeup_other(tp, FREAD|FWRITE); /* XXX */
 260         lwkt_reltoken(&tty_token);
 261         return (error);
 262 }
 263
 264 static int
 265 nmdmclose(struct dev_close_args *ap)
 266 {
 267         cdev_t dev = ap->a_head.a_dev;
 268         struct tty *tp, *tp2;
 269         int err;
 270         struct softpart *ourpart, *otherpart;
 271
 272         lwkt_gettoken(&tty_token);
 273         /*
 274          * let the other end know that the game is up
 275          */
 276         tp = dev->si_tty;
 277         GETPARTS(tp, ourpart, otherpart);
 278         tp2 = &otherpart->nm_tty;
 279         (void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
 280
 281         /*
 282          * XXX MDMBUF makes no sense for nmdms but would inhibit the above
 283          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 284          * l_modem()s that ignore carrier drop make no sense for nmdms but
 285          * may be in use because other parts of the line discipline make
 286          * sense for nmdms.  Recover by doing everything that a normal
 287          * ttymodem() would have done except for sending a SIGHUP.
 288          */
 289         if (tp2->t_state & TS_ISOPEN) {
 290                 tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 291                 tp2->t_state |= TS_ZOMBIE;
 292                 ttyflush(tp2, FREAD | FWRITE);
 293         }
 294
 295         err = (*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
 296         ourpart->modemsignals &= ~TIOCM_DTR;
 297         nmdm_crossover(dev->si_drv1, ourpart, otherpart);
 298         nmdmstop(tp, FREAD|FWRITE);
 299         (void) ttyclose(tp);
 300         lwkt_reltoken(&tty_token);
 301         return (err);
 302 }
 303
 304 static int
 305 nmdmread(struct dev_read_args *ap)
 306 {
 307         cdev_t dev = ap->a_head.a_dev;
 308         int error = 0;
 309         struct tty *tp;
 310 #if 0
 311         struct tty *tp2;
 312         struct softpart *ourpart, *otherpart;
 313 #endif
 314
 315         lwkt_gettoken(&tty_token);
 316         tp = dev->si_tty;
 317 #if 0
 318         GETPARTS(tp, ourpart, otherpart);
 319         tp2 = &otherpart->nm_tty;
 320
 321         if (tp2->t_state & TS_ISOPEN) {
 322                 error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
 323                 wakeup_other(tp, FWRITE);
 324         } else {
 325                 if (flag & IO_NDELAY) {
 326                         lwkt_reltoken(&tty_token);
 327                         return (EWOULDBLOCK);
 328                 }
 329                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 330                 }
 331         }
 332 #else
 333         if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
 334                 wakeup_other(tp, FWRITE);
 335 #endif
 336         lwkt_reltoken(&tty_token);
 337         return (error);
 338 }
 339
 340 /*
 341  * Write to pseudo-tty.
 342  * Wakeups of controlling tty will happen
 343  * indirectly, when tty driver calls nmdmstart.
 344  */
 345 static  int
 346 nmdmwrite(struct dev_write_args *ap)
 347 {
 348         cdev_t dev = ap->a_head.a_dev;
 349         struct uio *uio = ap->a_uio;
 350         u_char *cp = NULL;
 351         size_t cc = 0;
 352         u_char locbuf[BUFSIZ];
 353         int cnt = 0;
 354         int error = 0;
 355         struct tty *tp1, *tp;
 356         struct softpart *ourpart, *otherpart;
 357
 358         lwkt_gettoken(&tty_token);
 359         tp1 = dev->si_tty;
 360         /*
 361          * Get the other tty struct.
 362          * basically we are writing into the INPUT side of the other device.
 363          */
 364         GETPARTS(tp1, ourpart, otherpart);
 365         tp = &otherpart->nm_tty;
 366
 367 again:
 368         if ((tp->t_state & TS_ISOPEN) == 0) {
 369                 lwkt_reltoken(&tty_token);
 370                 return (EIO);
 371         }
 372         while (uio->uio_resid > 0 || cc > 0) {
 373                 /*
 374                  * Fill up the buffer if it's empty
 375                  */
 376                 if (cc == 0) {
 377                         cc = szmin(uio->uio_resid, BUFSIZ);
 378                         cp = locbuf;
 379                         error = uiomove((caddr_t)cp, cc, uio);
 380                         if (error) {
 381                                 lwkt_reltoken(&tty_token);
 382                                 return (error);
 383                         }
 384                         /* check again for safety */
 385                         if ((tp->t_state & TS_ISOPEN) == 0) {
 386                                 /* adjust for data copied in but not written */
 387                                 uio->uio_resid += cc;
 388                                 lwkt_reltoken(&tty_token);
 389                                 return (EIO);
 390                         }
 391                 }
 392                 while (cc > 0) {
 393                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 394                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 395                                 /*
 396                                  * Come here to wait for space in outq,
 397                                  * or space in rawq, or an empty canq.
 398                                  */
 399                                 wakeup(TSA_HUP_OR_INPUT(tp));
 400                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 401                                         /*
 402                                          * Data piled up because not connected.
 403                                          * Adjust for data copied in but
 404                                          * not written.
 405                                          */
 406                                         uio->uio_resid += cc;
 407                                         lwkt_reltoken(&tty_token);
 408                                         return (EIO);
 409                                 }
 410                                 if (ap->a_ioflag & IO_NDELAY) {
 411                                         /*
 412                                          * Don't wait if asked not to.
 413                                          * Adjust for data copied in but
 414                                          * not written.
 415                                          */
 416                                         uio->uio_resid += cc;
 417                                         if (cnt == 0) {
 418                                                 lwkt_reltoken(&tty_token);
 419                                                 return (EWOULDBLOCK);
 420                                         }
 421                                         lwkt_reltoken(&tty_token);
 422                                         return (0);
 423                                 }
 424                                 error = tsleep(TSA_PTC_WRITE(tp),
 425                                                 PCATCH, "nmdout", 0);
 426                                 if (error) {
 427                                         /*
 428                                          * Tsleep returned (signal?).
 429                                          * Go find out what the user wants.
 430                                          * adjust for data copied in but
 431                                          * not written
 432                                          */
 433                                         uio->uio_resid += cc;
 434                                         lwkt_reltoken(&tty_token);
 435                                         return (error);
 436                                 }
 437                                 goto again;
 438                         }
 439                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 440                         cnt++;
 441                         cc--;
 442                 }
 443                 cc = 0;
 444         }
 445         lwkt_reltoken(&tty_token);
 446         return (0);
 447 }
 448
 449 /*
 450  * Start output on pseudo-tty.
 451  * Wake up process selecting or sleeping for input from controlling tty.
 452  */
 453 static void
 454 nmdmstart(struct tty *tp)
 455 {
 456         struct nm_softc *pti = tp->t_dev->si_drv1;
 457
 458         lwkt_gettoken(&tty_token);
 459         if (tp->t_state & TS_TTSTOP) {
 460                 lwkt_reltoken(&tty_token);
 461                 return;
 462         }
 463         pti->pt_flags &= ~PF_STOPPED;
 464         wakeup_other(tp, FREAD);
 465         lwkt_reltoken(&tty_token);
 466 }
 467
 468 /* Wakes up the OTHER tty;*/
 469 static void
 470 wakeup_other(struct tty *tp, int flag)
 471 {
 472         struct softpart *ourpart, *otherpart;
 473
 474         lwkt_gettoken(&tty_token);
 475         GETPARTS(tp, ourpart, otherpart);
 476         if (flag & FREAD) {
 477                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 478                 KNOTE(&otherpart->nm_tty.t_rkq.ki_note, 0);
 479         }
 480         if (flag & FWRITE) {
 481                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 482                 KNOTE(&otherpart->nm_tty.t_wkq.ki_note, 0);
 483         }
 484         lwkt_reltoken(&tty_token);
 485 }
 486
 487 static  void
 488 nmdmstop(struct tty *tp, int flush)
 489 {
 490         struct nm_softc *pti = tp->t_dev->si_drv1;
 491         int flag;
 492
 493         lwkt_gettoken(&tty_token);
 494         /* note: FLUSHREAD and FLUSHWRITE already ok */
 495         if (flush == 0) {
 496                 flush = TIOCPKT_STOP;
 497                 pti->pt_flags |= PF_STOPPED;
 498         } else
 499                 pti->pt_flags &= ~PF_STOPPED;
 500         /* change of perspective */
 501         flag = 0;
 502         if (flush & FREAD)
 503                 flag |= FWRITE;
 504         if (flush & FWRITE)
 505                 flag |= FREAD;
 506         wakeup_other(tp, flag);
 507         lwkt_reltoken(&tty_token);
 508 }
 509
 510 /*ARGSUSED*/
 511 static  int
 512 nmdmioctl(struct dev_ioctl_args *ap)
 513 {
 514         cdev_t dev = ap->a_head.a_dev;
 515         struct tty *tp = dev->si_tty;
 516         struct nm_softc *pti = dev->si_drv1;
 517         int error;
 518         struct softpart *ourpart, *otherpart;
 519
 520         crit_enter();
 521         lwkt_gettoken(&tty_token);
 522         GETPARTS(tp, ourpart, otherpart);
 523
 524         error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
 525                                               ap->a_fflag, ap->a_cred);
 526         if (error == ENOIOCTL)
 527                  error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
 528         if (error == ENOIOCTL) {
 529                 switch (ap->a_cmd) {
 530                 case TIOCSBRK:
 531                         otherpart->gotbreak = 1;
 532                         break;
 533                 case TIOCCBRK:
 534                         break;
 535                 case TIOCSDTR:
 536                         ourpart->modemsignals |= TIOCM_DTR;
 537                         break;
 538                 case TIOCCDTR:
 539                         ourpart->modemsignals &= TIOCM_DTR;
 540                         break;
 541                 case TIOCMSET:
 542                         ourpart->modemsignals = *(int *)ap->a_data;
 543                         otherpart->modemsignals = *(int *)ap->a_data;
 544                         break;
 545                 case TIOCMBIS:
 546                         ourpart->modemsignals |= *(int *)ap->a_data;
 547                         break;
 548                 case TIOCMBIC:
 549                         ourpart->modemsignals &= ~(*(int *)ap->a_data);
 550                         otherpart->modemsignals &= ~(*(int *)ap->a_data);
 551                         break;
 552                 case TIOCMGET:
 553                         *(int *)ap->a_data = ourpart->modemsignals;
 554                         break;
 555                 case TIOCMSDTRWAIT:
 556                         break;
 557                 case TIOCMGDTRWAIT:
 558                         *(int *)ap->a_data = 0;
 559                         break;
 560                 case TIOCTIMESTAMP:
 561                 case TIOCDCDTIMESTAMP:
 562                 default:
 563                         lwkt_reltoken(&tty_token);
 564                         crit_exit();
 565                         error = ENOTTY;
 566                         return (error);
 567                 }
 568                 error = 0;
 569                 nmdm_crossover(pti, ourpart, otherpart);
 570         }
 571         lwkt_reltoken(&tty_token);
 572         crit_exit();
 573         return (error);
 574 }
 575
 576 static void
 577 nmdm_crossover(struct nm_softc *pti,
 578                 struct softpart *ourpart,
 579                 struct softpart *otherpart)
 580 {
 581         lwkt_gettoken(&tty_token);
 582         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 583         if (ourpart->modemsignals & TIOCM_RTS)
 584                 otherpart->modemsignals |= TIOCM_CTS;
 585         if (ourpart->modemsignals & TIOCM_DTR)
 586                 otherpart->modemsignals |= TIOCM_CAR;
 587         lwkt_reltoken(&tty_token);
 588 }
 589
 590
 591
 592 static void nmdm_drvinit (void *unused);
 593
 594 static void
 595 nmdm_drvinit(void *unused)
 596 {
 597         /* XXX: Gross hack for DEVFS */
 598         lwkt_gettoken(&tty_token);
 599         nmdminit(0);
 600         lwkt_reltoken(&tty_token);
 601 }
 602
 603 SYSINIT(nmdmdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE + CDEV_MAJOR, nmdm_drvinit,
 604     NULL);