sys/dev/misc/nmdm/nmdm.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  * $FreeBSD: src/sys/dev/nmdm/nmdm.c,v 1.5.2.1 2001/08/11 00:54:14 mp Exp $
  34  * $DragonFly: src/sys/dev/misc/nmdm/nmdm.c,v 1.5 2003/07/19 21:14:25 dillon Exp $
  35  */
  36
  37 /*
  38  * Pseudo-nulmodem Driver
  39  */
  40 #include "opt_compat.h"
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
  44 #include <sys/ioctl_compat.h>
  45 #endif
  46 #include <sys/proc.h>
  47 #include <sys/tty.h>
  48 #include <sys/conf.h>
  49 #include <sys/fcntl.h>
  50 #include <sys/poll.h>
  51 #include <sys/kernel.h>
  52 #include <sys/vnode.h>
  53 #include <sys/signalvar.h>
  54 #include <sys/malloc.h>
  55
  56 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
  57
  58 static void nmdmstart __P((struct tty *tp));
  59 static void nmdmstop __P((struct tty *tp, int rw));
  60 static void wakeup_other __P((struct tty *tp, int flag));
  61 static void nmdminit __P((int n));
  62
  63 static  d_open_t        nmdmopen;
  64 static  d_close_t       nmdmclose;
  65 static  d_read_t        nmdmread;
  66 static  d_write_t       nmdmwrite;
  67 static  d_ioctl_t       nmdmioctl;
  68
  69 #define CDEV_MAJOR      18
  70 static struct cdevsw nmdm_cdevsw = {
  71         /* open */      nmdmopen,
  72         /* close */     nmdmclose,
  73         /* read */      nmdmread,
  74         /* write */     nmdmwrite,
  75         /* ioctl */     nmdmioctl,
  76         /* poll */      ttypoll,
  77         /* mmap */      nommap,
  78         /* strategy */  nostrategy,
  79         /* name */      "pts",
  80         /* maj */       CDEV_MAJOR,
  81         /* dump */      nodump,
  82         /* psize */     nopsize,
  83         /* flags */     D_TTY,
  84         /* bmaj */      -1
  85 };
  86
  87 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
  88
  89 struct softpart {
  90         struct tty nm_tty;
  91         dev_t   dev;
  92         int     modemsignals;   /* bits defined in sys/ttycom.h */
  93         int     gotbreak;
  94 };
  95
  96 struct  nm_softc {
  97         int     pt_flags;
  98         struct softpart part1, part2;
  99         struct  prison *pt_prison;
 100 };
 101
 102 #define PF_STOPPED      0x10            /* user told stopped */
 103
 104 static void
 105 nmdm_crossover(struct nm_softc *pti,
 106                 struct softpart *ourpart,
 107                 struct softpart *otherpart);
 108
 109 #define GETPARTS(tp, ourpart, otherpart) \
 110 do {    \
 111         struct nm_softc *pti = tp->t_dev->si_drv1; \
 112         if (tp == &pti->part1.nm_tty) { \
 113                 ourpart = &pti->part1; \
 114                 otherpart = &pti->part2; \
 115         } else { \
 116                 ourpart = &pti->part2; \
 117                 otherpart = &pti->part1; \
 118         }  \
 119 } while (0)
 120
 121 /*
 122  * This function creates and initializes a pair of ttys.
 123  */
 124 static void
 125 nmdminit(n)
 126         int n;
 127 {
 128         dev_t dev1, dev2;
 129         struct nm_softc *pt;
 130
 131         /* For now we only map the lower 8 bits of the minor */
 132         if (n & ~0xff)
 133                 return;
 134
 135         pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
 136         bzero(pt, sizeof(*pt));
 137         pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n+n,
 138             0, 0, 0666, "nmdm%dA", n);
 139         pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, n+n+1,
 140             0, 0, 0666, "nmdm%dB", n);
 141
 142         dev1->si_drv1 = dev2->si_drv1 = pt;
 143         dev1->si_tty = &pt->part1.nm_tty;
 144         dev2->si_tty = &pt->part2.nm_tty;
 145         ttyregister(&pt->part1.nm_tty);
 146         ttyregister(&pt->part2.nm_tty);
 147         pt->part1.nm_tty.t_oproc = nmdmstart;
 148         pt->part2.nm_tty.t_oproc = nmdmstart;
 149         pt->part1.nm_tty.t_stop = nmdmstop;
 150         pt->part2.nm_tty.t_dev = dev1;
 151         pt->part1.nm_tty.t_dev = dev2;
 152         pt->part2.nm_tty.t_stop = nmdmstop;
 153 }
 154
 155 /*ARGSUSED*/
 156 static  int
 157 nmdmopen(dev_t dev, int flag, int devtype, struct thread *td)
 158 {
 159         struct proc *p = td->td_proc;
 160         struct tty *tp, *tp2;
 161         int error;
 162         int minr;
 163         dev_t nextdev;
 164         struct nm_softc *pti;
 165         int is_b;
 166         int     pair;
 167         struct  softpart *ourpart, *otherpart;
 168
 169         KKASSERT(p != NULL);
 170
 171         /*
 172          * XXX: Gross hack for DEVFS:
 173          * If we openned this device, ensure we have the
 174          * next one too, so people can open it.
 175          */
 176         minr = lminor(dev);
 177         pair = minr >> 1;
 178         is_b = minr & 1;
 179
 180         if (pair < 127) {
 181                 nextdev = makedev(major(dev), (pair+pair) + 1);
 182                 if (!nextdev->si_drv1) {
 183                         nmdminit(pair + 1);
 184                 }
 185         }
 186         if (!dev->si_drv1)
 187                 nmdminit(pair);
 188
 189         if (!dev->si_drv1)
 190                 return(ENXIO);
 191
 192         pti = dev->si_drv1;
 193         if (is_b)
 194                 tp = &pti->part2.nm_tty;
 195         else
 196                 tp = &pti->part1.nm_tty;
 197         GETPARTS(tp, ourpart, otherpart);
 198         tp2 = &otherpart->nm_tty;
 199         ourpart->modemsignals |= TIOCM_LE;
 200
 201         if ((tp->t_state & TS_ISOPEN) == 0) {
 202                 ttychars(tp);           /* Set up default chars */
 203                 tp->t_iflag = TTYDEF_IFLAG;
 204                 tp->t_oflag = TTYDEF_OFLAG;
 205                 tp->t_lflag = TTYDEF_LFLAG;
 206                 tp->t_cflag = TTYDEF_CFLAG;
 207                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 208         } else if (tp->t_state & TS_XCLUDE && suser(td)) {
 209                 return (EBUSY);
 210         } else if (pti->pt_prison != p->p_ucred->cr_prison) {
 211                 return (EBUSY);
 212         }
 213
 214         /*
 215          * If the other side is open we have carrier
 216          */
 217         if (tp2->t_state & TS_ISOPEN) {
 218                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 219         }
 220
 221         /*
 222          * And the other side gets carrier as we are now open.
 223          */
 224         (void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
 225
 226         /* External processing makes no sense here */
 227         tp->t_lflag &= ~EXTPROC;
 228
 229         /*
 230          * Wait here if we don't have carrier.
 231          */
 232 #if 0
 233         while ((tp->t_state & TS_CARR_ON) == 0) {
 234                 if (flag & FNONBLOCK)
 235                         break;
 236                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
 237                 if (error)
 238                         return (error);
 239         }
 240 #endif
 241
 242         /*
 243          * Give the line disciplin a chance to set this end up.
 244          */
 245         error = (*linesw[tp->t_line].l_open)(dev, tp);
 246
 247         /*
 248          * Wake up the other side.
 249          * Theoretically not needed.
 250          */
 251         ourpart->modemsignals |= TIOCM_DTR;
 252         nmdm_crossover(pti, ourpart, otherpart);
 253         if (error == 0)
 254                 wakeup_other(tp, FREAD|FWRITE); /* XXX */
 255         return (error);
 256 }
 257
 258 static  int
 259 nmdmclose(dev_t dev, int flag, int mode, struct thread *td)
 260 {
 261         register struct tty *tp, *tp2;
 262         int err;
 263         struct softpart *ourpart, *otherpart;
 264
 265         /*
 266          * let the other end know that the game is up
 267          */
 268         tp = dev->si_tty;
 269         GETPARTS(tp, ourpart, otherpart);
 270         tp2 = &otherpart->nm_tty;
 271         (void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
 272
 273         /*
 274          * XXX MDMBUF makes no sense for nmdms but would inhibit the above
 275          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 276          * l_modem()s that ignore carrier drop make no sense for nmdms but
 277          * may be in use because other parts of the line discipline make
 278          * sense for nmdms.  Recover by doing everything that a normal
 279          * ttymodem() would have done except for sending a SIGHUP.
 280          */
 281         if (tp2->t_state & TS_ISOPEN) {
 282                 tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 283                 tp2->t_state |= TS_ZOMBIE;
 284                 ttyflush(tp2, FREAD | FWRITE);
 285         }
 286
 287         err = (*linesw[tp->t_line].l_close)(tp, flag);
 288         ourpart->modemsignals &= ~TIOCM_DTR;
 289         nmdm_crossover(dev->si_drv1, ourpart, otherpart);
 290         nmdmstop(tp, FREAD|FWRITE);
 291         (void) ttyclose(tp);
 292         return (err);
 293 }
 294
 295 static  int
 296 nmdmread(dev, uio, flag)
 297         dev_t dev;
 298         struct uio *uio;
 299         int flag;
 300 {
 301         int error = 0;
 302         struct tty *tp, *tp2;
 303         struct softpart *ourpart, *otherpart;
 304
 305         tp = dev->si_tty;
 306         GETPARTS(tp, ourpart, otherpart);
 307         tp2 = &otherpart->nm_tty;
 308
 309 #if 0
 310         if (tp2->t_state & TS_ISOPEN) {
 311                 error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
 312                 wakeup_other(tp, FWRITE);
 313         } else {
 314                 if (flag & IO_NDELAY) {
 315                         return (EWOULDBLOCK);
 316                 }
 317                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 318                 }
 319         }
 320 #else
 321         if ((error = (*linesw[tp->t_line].l_read)(tp, uio, flag)) == 0)
 322                 wakeup_other(tp, FWRITE);
 323 #endif
 324         return (error);
 325 }
 326
 327 /*
 328  * Write to pseudo-tty.
 329  * Wakeups of controlling tty will happen
 330  * indirectly, when tty driver calls nmdmstart.
 331  */
 332 static  int
 333 nmdmwrite(dev, uio, flag)
 334         dev_t dev;
 335         struct uio *uio;
 336         int flag;
 337 {
 338         register u_char *cp = 0;
 339         register int cc = 0;
 340         u_char locbuf[BUFSIZ];
 341         int cnt = 0;
 342         int error = 0;
 343         struct tty *tp1, *tp;
 344         struct softpart *ourpart, *otherpart;
 345
 346         tp1 = dev->si_tty;
 347         /*
 348          * Get the other tty struct.
 349          * basically we are writing into the INPUT side of the other device.
 350          */
 351         GETPARTS(tp1, ourpart, otherpart);
 352         tp = &otherpart->nm_tty;
 353
 354 again:
 355         if ((tp->t_state & TS_ISOPEN) == 0)
 356                 return (EIO);
 357         while (uio->uio_resid > 0 || cc > 0) {
 358                 /*
 359                  * Fill up the buffer if it's empty
 360                  */
 361                 if (cc == 0) {
 362                         cc = min(uio->uio_resid, BUFSIZ);
 363                         cp = locbuf;
 364                         error = uiomove((caddr_t)cp, cc, uio);
 365                         if (error)
 366                                 return (error);
 367                         /* check again for safety */
 368                         if ((tp->t_state & TS_ISOPEN) == 0) {
 369                                 /* adjust for data copied in but not written */
 370                                 uio->uio_resid += cc;
 371                                 return (EIO);
 372                         }
 373                 }
 374                 while (cc > 0) {
 375                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 376                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 377                                 /*
 378                                  * Come here to wait for space in outq,
 379                                  * or space in rawq, or an empty canq.
 380                                  */
 381                                 wakeup(TSA_HUP_OR_INPUT(tp));
 382                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 383                                         /*
 384                                          * Data piled up because not connected.
 385                                          * Adjust for data copied in but
 386                                          * not written.
 387                                          */
 388                                         uio->uio_resid += cc;
 389                                         return (EIO);
 390                                 }
 391                                 if (flag & IO_NDELAY) {
 392                                         /*
 393                                          * Don't wait if asked not to.
 394                                          * Adjust for data copied in but
 395                                          * not written.
 396                                          */
 397                                         uio->uio_resid += cc;
 398                                         if (cnt == 0)
 399                                                 return (EWOULDBLOCK);
 400                                         return (0);
 401                                 }
 402                                 error = tsleep(TSA_PTC_WRITE(tp),
 403                                                 PCATCH, "nmdout", 0);
 404                                 if (error) {
 405                                         /*
 406                                          * Tsleep returned (signal?).
 407                                          * Go find out what the user wants.
 408                                          * adjust for data copied in but
 409                                          * not written
 410                                          */
 411                                         uio->uio_resid += cc;
 412                                         return (error);
 413                                 }
 414                                 goto again;
 415                         }
 416                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 417                         cnt++;
 418                         cc--;
 419                 }
 420                 cc = 0;
 421         }
 422         return (0);
 423 }
 424
 425 /*
 426  * Start output on pseudo-tty.
 427  * Wake up process selecting or sleeping for input from controlling tty.
 428  */
 429 static void
 430 nmdmstart(tp)
 431         struct tty *tp;
 432 {
 433         register struct nm_softc *pti = tp->t_dev->si_drv1;
 434
 435         if (tp->t_state & TS_TTSTOP)
 436                 return;
 437         pti->pt_flags &= ~PF_STOPPED;
 438         wakeup_other(tp, FREAD);
 439 }
 440
 441 /* Wakes up the OTHER tty;*/
 442 static void
 443 wakeup_other(tp, flag)
 444         struct tty *tp;
 445         int flag;
 446 {
 447         struct softpart *ourpart, *otherpart;
 448
 449         GETPARTS(tp, ourpart, otherpart);
 450         if (flag & FREAD) {
 451                 selwakeup(&otherpart->nm_tty.t_rsel);
 452                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 453         }
 454         if (flag & FWRITE) {
 455                 selwakeup(&otherpart->nm_tty.t_wsel);
 456                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 457         }
 458 }
 459
 460 static  void
 461 nmdmstop(tp, flush)
 462         register struct tty *tp;
 463         int flush;
 464 {
 465         struct nm_softc *pti = tp->t_dev->si_drv1;
 466         int flag;
 467
 468         /* note: FLUSHREAD and FLUSHWRITE already ok */
 469         if (flush == 0) {
 470                 flush = TIOCPKT_STOP;
 471                 pti->pt_flags |= PF_STOPPED;
 472         } else
 473                 pti->pt_flags &= ~PF_STOPPED;
 474         /* change of perspective */
 475         flag = 0;
 476         if (flush & FREAD)
 477                 flag |= FWRITE;
 478         if (flush & FWRITE)
 479                 flag |= FREAD;
 480         wakeup_other(tp, flag);
 481 }
 482
 483 /*ARGSUSED*/
 484 static  int
 485 nmdmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
 486 {
 487         register struct tty *tp = dev->si_tty;
 488         struct nm_softc *pti = dev->si_drv1;
 489         int error, s;
 490         register struct tty *tp2;
 491         struct softpart *ourpart, *otherpart;
 492
 493         s = spltty();
 494         GETPARTS(tp, ourpart, otherpart);
 495         tp2 = &otherpart->nm_tty;
 496
 497         error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, td);
 498         if (error == ENOIOCTL)
 499                  error = ttioctl(tp, cmd, data, flag);
 500         if (error == ENOIOCTL) {
 501                 switch (cmd) {
 502                 case TIOCSBRK:
 503                         otherpart->gotbreak = 1;
 504                         break;
 505                 case TIOCCBRK:
 506                         break;
 507                 case TIOCSDTR:
 508                         ourpart->modemsignals |= TIOCM_DTR;
 509                         break;
 510                 case TIOCCDTR:
 511                         ourpart->modemsignals &= TIOCM_DTR;
 512                         break;
 513                 case TIOCMSET:
 514                         ourpart->modemsignals = *(int *)data;
 515                         otherpart->modemsignals = *(int *)data;
 516                         break;
 517                 case TIOCMBIS:
 518                         ourpart->modemsignals |= *(int *)data;
 519                         break;
 520                 case TIOCMBIC:
 521                         ourpart->modemsignals &= ~(*(int *)data);
 522                         otherpart->modemsignals &= ~(*(int *)data);
 523                         break;
 524                 case TIOCMGET:
 525                         *(int *)data = ourpart->modemsignals;
 526                         break;
 527                 case TIOCMSDTRWAIT:
 528                         break;
 529                 case TIOCMGDTRWAIT:
 530                         *(int *)data = 0;
 531                         break;
 532                 case TIOCTIMESTAMP:
 533                 case TIOCDCDTIMESTAMP:
 534                 default:
 535                         splx(s);
 536                         error = ENOTTY;
 537                         return (error);
 538                 }
 539                 error = 0;
 540                 nmdm_crossover(pti, ourpart, otherpart);
 541         }
 542         splx(s);
 543         return (error);
 544 }
 545
 546 static void
 547 nmdm_crossover(struct nm_softc *pti,
 548                 struct softpart *ourpart,
 549                 struct softpart *otherpart)
 550 {
 551         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 552         if (ourpart->modemsignals & TIOCM_RTS)
 553                 otherpart->modemsignals |= TIOCM_CTS;
 554         if (ourpart->modemsignals & TIOCM_DTR)
 555                 otherpart->modemsignals |= TIOCM_CAR;
 556 }
 557
 558
 559
 560 static void nmdm_drvinit __P((void *unused));
 561
 562 static void
 563 nmdm_drvinit(unused)
 564         void *unused;
 565 {
 566         cdevsw_add(&nmdm_cdevsw);
 567         /* XXX: Gross hack for DEVFS */
 568         nmdminit(0);
 569 }
 570
 571 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)