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 1.10 2004/05/19 22:52:43 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 (struct tty *tp);
  59 static void nmdmstop (struct tty *tp, int rw);
  60 static void wakeup_other (struct tty *tp, int flag);
  61 static void nmdminit (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         /* name */      "pts",
  72         /* maj */       CDEV_MAJOR,
  73         /* flags */     D_TTY,
  74         /* port */      NULL,
  75         /* clone */     NULL,
  76
  77         /* open */      nmdmopen,
  78         /* close */     nmdmclose,
  79         /* read */      nmdmread,
  80         /* write */     nmdmwrite,
  81         /* ioctl */     nmdmioctl,
  82         /* poll */      ttypoll,
  83         /* mmap */      nommap,
  84         /* strategy */  nostrategy,
  85         /* dump */      nodump,
  86         /* psize */     nopsize
  87 };
  88
  89 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
  90
  91 struct softpart {
  92         struct tty nm_tty;
  93         dev_t   dev;
  94         int     modemsignals;   /* bits defined in sys/ttycom.h */
  95         int     gotbreak;
  96 };
  97
  98 struct  nm_softc {
  99         int     pt_flags;
 100         struct softpart part1, part2;
 101         struct  prison *pt_prison;
 102 };
 103
 104 #define PF_STOPPED      0x10            /* user told stopped */
 105
 106 static void
 107 nmdm_crossover(struct nm_softc *pti,
 108                 struct softpart *ourpart,
 109                 struct softpart *otherpart);
 110
 111 #define GETPARTS(tp, ourpart, otherpart) \
 112 do {    \
 113         struct nm_softc *pti = tp->t_dev->si_drv1; \
 114         if (tp == &pti->part1.nm_tty) { \
 115                 ourpart = &pti->part1; \
 116                 otherpart = &pti->part2; \
 117         } else { \
 118                 ourpart = &pti->part2; \
 119                 otherpart = &pti->part1; \
 120         }  \
 121 } while (0)
 122
 123 /*
 124  * This function creates and initializes a pair of ttys.
 125  */
 126 static void
 127 nmdminit(n)
 128         int n;
 129 {
 130         dev_t dev1, dev2;
 131         struct nm_softc *pt;
 132
 133         /*
 134          * Simplified unit number, use low 8 bits of minor number
 135          * (remember, the minor number mask is 0xffff00ff).
 136          */
 137         if (n & ~0x7f)
 138                 return;
 139
 140         pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
 141         bzero(pt, sizeof(*pt));
 142         cdevsw_add(&nmdm_cdevsw, ~1, n << 1);
 143         pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n << 1,
 144             0, 0, 0666, "nmdm%dA", n);
 145         pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, (n << 1) + 1,
 146             0, 0, 0666, "nmdm%dB", n);
 147
 148         dev1->si_drv1 = dev2->si_drv1 = pt;
 149         dev1->si_tty = &pt->part1.nm_tty;
 150         dev2->si_tty = &pt->part2.nm_tty;
 151         ttyregister(&pt->part1.nm_tty);
 152         ttyregister(&pt->part2.nm_tty);
 153         pt->part1.nm_tty.t_oproc = nmdmstart;
 154         pt->part2.nm_tty.t_oproc = nmdmstart;
 155         pt->part1.nm_tty.t_stop = nmdmstop;
 156         pt->part2.nm_tty.t_dev = dev1;
 157         pt->part1.nm_tty.t_dev = dev2;
 158         pt->part2.nm_tty.t_stop = nmdmstop;
 159 }
 160
 161 /*ARGSUSED*/
 162 static  int
 163 nmdmopen(dev_t dev, int flag, int devtype, struct thread *td)
 164 {
 165         struct proc *p = td->td_proc;
 166         struct tty *tp, *tp2;
 167         int error;
 168         int minr;
 169 #if 0
 170         dev_t nextdev;
 171 #endif
 172         struct nm_softc *pti;
 173         int is_b;
 174         int     pair;
 175         struct  softpart *ourpart, *otherpart;
 176
 177         KKASSERT(p != NULL);
 178
 179         minr = lminor(dev);
 180         pair = minr >> 1;
 181         is_b = minr & 1;
 182
 183 #if 0
 184         /*
 185          * XXX: Gross hack for DEVFS:
 186          * If we openned this device, ensure we have the
 187          * next one too, so people can open it.
 188          */
 189         if (pair < 127) {
 190                 nextdev = makedev(major(dev), (pair+pair) + 1);
 191                 if (!nextdev->si_drv1) {
 192                         nmdminit(pair + 1);
 193                 }
 194         }
 195 #endif
 196         if (!dev->si_drv1)
 197                 nmdminit(pair);
 198
 199         if (!dev->si_drv1)
 200                 return(ENXIO);
 201
 202         pti = dev->si_drv1;
 203         if (is_b)
 204                 tp = &pti->part2.nm_tty;
 205         else
 206                 tp = &pti->part1.nm_tty;
 207         GETPARTS(tp, ourpart, otherpart);
 208         tp2 = &otherpart->nm_tty;
 209         ourpart->modemsignals |= TIOCM_LE;
 210
 211         if ((tp->t_state & TS_ISOPEN) == 0) {
 212                 ttychars(tp);           /* Set up default chars */
 213                 tp->t_iflag = TTYDEF_IFLAG;
 214                 tp->t_oflag = TTYDEF_OFLAG;
 215                 tp->t_lflag = TTYDEF_LFLAG;
 216                 tp->t_cflag = TTYDEF_CFLAG;
 217                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 218         } else if (tp->t_state & TS_XCLUDE && suser(td)) {
 219                 return (EBUSY);
 220         } else if (pti->pt_prison != p->p_ucred->cr_prison) {
 221                 return (EBUSY);
 222         }
 223
 224         /*
 225          * If the other side is open we have carrier
 226          */
 227         if (tp2->t_state & TS_ISOPEN) {
 228                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 229         }
 230
 231         /*
 232          * And the other side gets carrier as we are now open.
 233          */
 234         (void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
 235
 236         /* External processing makes no sense here */
 237         tp->t_lflag &= ~EXTPROC;
 238
 239         /*
 240          * Wait here if we don't have carrier.
 241          */
 242 #if 0
 243         while ((tp->t_state & TS_CARR_ON) == 0) {
 244                 if (flag & FNONBLOCK)
 245                         break;
 246                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
 247                 if (error)
 248                         return (error);
 249         }
 250 #endif
 251
 252         /*
 253          * Give the line disciplin a chance to set this end up.
 254          */
 255         error = (*linesw[tp->t_line].l_open)(dev, tp);
 256
 257         /*
 258          * Wake up the other side.
 259          * Theoretically not needed.
 260          */
 261         ourpart->modemsignals |= TIOCM_DTR;
 262         nmdm_crossover(pti, ourpart, otherpart);
 263         if (error == 0)
 264                 wakeup_other(tp, FREAD|FWRITE); /* XXX */
 265         return (error);
 266 }
 267
 268 static  int
 269 nmdmclose(dev_t dev, int flag, int mode, struct thread *td)
 270 {
 271         struct tty *tp, *tp2;
 272         int err;
 273         struct softpart *ourpart, *otherpart;
 274
 275         /*
 276          * let the other end know that the game is up
 277          */
 278         tp = dev->si_tty;
 279         GETPARTS(tp, ourpart, otherpart);
 280         tp2 = &otherpart->nm_tty;
 281         (void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
 282
 283         /*
 284          * XXX MDMBUF makes no sense for nmdms but would inhibit the above
 285          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 286          * l_modem()s that ignore carrier drop make no sense for nmdms but
 287          * may be in use because other parts of the line discipline make
 288          * sense for nmdms.  Recover by doing everything that a normal
 289          * ttymodem() would have done except for sending a SIGHUP.
 290          */
 291         if (tp2->t_state & TS_ISOPEN) {
 292                 tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 293                 tp2->t_state |= TS_ZOMBIE;
 294                 ttyflush(tp2, FREAD | FWRITE);
 295         }
 296
 297         err = (*linesw[tp->t_line].l_close)(tp, flag);
 298         ourpart->modemsignals &= ~TIOCM_DTR;
 299         nmdm_crossover(dev->si_drv1, ourpart, otherpart);
 300         nmdmstop(tp, FREAD|FWRITE);
 301         (void) ttyclose(tp);
 302         return (err);
 303 }
 304
 305 static  int
 306 nmdmread(dev, uio, flag)
 307         dev_t dev;
 308         struct uio *uio;
 309         int flag;
 310 {
 311         int error = 0;
 312         struct tty *tp, *tp2;
 313         struct softpart *ourpart, *otherpart;
 314
 315         tp = dev->si_tty;
 316         GETPARTS(tp, ourpart, otherpart);
 317         tp2 = &otherpart->nm_tty;
 318
 319 #if 0
 320         if (tp2->t_state & TS_ISOPEN) {
 321                 error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
 322                 wakeup_other(tp, FWRITE);
 323         } else {
 324                 if (flag & IO_NDELAY) {
 325                         return (EWOULDBLOCK);
 326                 }
 327                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 328                 }
 329         }
 330 #else
 331         if ((error = (*linesw[tp->t_line].l_read)(tp, uio, flag)) == 0)
 332                 wakeup_other(tp, FWRITE);
 333 #endif
 334         return (error);
 335 }
 336
 337 /*
 338  * Write to pseudo-tty.
 339  * Wakeups of controlling tty will happen
 340  * indirectly, when tty driver calls nmdmstart.
 341  */
 342 static  int
 343 nmdmwrite(dev, uio, flag)
 344         dev_t dev;
 345         struct uio *uio;
 346         int flag;
 347 {
 348         u_char *cp = 0;
 349         int cc = 0;
 350         u_char locbuf[BUFSIZ];
 351         int cnt = 0;
 352         int error = 0;
 353         struct tty *tp1, *tp;
 354         struct softpart *ourpart, *otherpart;
 355
 356         tp1 = dev->si_tty;
 357         /*
 358          * Get the other tty struct.
 359          * basically we are writing into the INPUT side of the other device.
 360          */
 361         GETPARTS(tp1, ourpart, otherpart);
 362         tp = &otherpart->nm_tty;
 363
 364 again:
 365         if ((tp->t_state & TS_ISOPEN) == 0)
 366                 return (EIO);
 367         while (uio->uio_resid > 0 || cc > 0) {
 368                 /*
 369                  * Fill up the buffer if it's empty
 370                  */
 371                 if (cc == 0) {
 372                         cc = min(uio->uio_resid, BUFSIZ);
 373                         cp = locbuf;
 374                         error = uiomove((caddr_t)cp, cc, uio);
 375                         if (error)
 376                                 return (error);
 377                         /* check again for safety */
 378                         if ((tp->t_state & TS_ISOPEN) == 0) {
 379                                 /* adjust for data copied in but not written */
 380                                 uio->uio_resid += cc;
 381                                 return (EIO);
 382                         }
 383                 }
 384                 while (cc > 0) {
 385                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 386                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 387                                 /*
 388                                  * Come here to wait for space in outq,
 389                                  * or space in rawq, or an empty canq.
 390                                  */
 391                                 wakeup(TSA_HUP_OR_INPUT(tp));
 392                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 393                                         /*
 394                                          * Data piled up because not connected.
 395                                          * Adjust for data copied in but
 396                                          * not written.
 397                                          */
 398                                         uio->uio_resid += cc;
 399                                         return (EIO);
 400                                 }
 401                                 if (flag & IO_NDELAY) {
 402                                         /*
 403                                          * Don't wait if asked not to.
 404                                          * Adjust for data copied in but
 405                                          * not written.
 406                                          */
 407                                         uio->uio_resid += cc;
 408                                         if (cnt == 0)
 409                                                 return (EWOULDBLOCK);
 410                                         return (0);
 411                                 }
 412                                 error = tsleep(TSA_PTC_WRITE(tp),
 413                                                 PCATCH, "nmdout", 0);
 414                                 if (error) {
 415                                         /*
 416                                          * Tsleep returned (signal?).
 417                                          * Go find out what the user wants.
 418                                          * adjust for data copied in but
 419                                          * not written
 420                                          */
 421                                         uio->uio_resid += cc;
 422                                         return (error);
 423                                 }
 424                                 goto again;
 425                         }
 426                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 427                         cnt++;
 428                         cc--;
 429                 }
 430                 cc = 0;
 431         }
 432         return (0);
 433 }
 434
 435 /*
 436  * Start output on pseudo-tty.
 437  * Wake up process selecting or sleeping for input from controlling tty.
 438  */
 439 static void
 440 nmdmstart(tp)
 441         struct tty *tp;
 442 {
 443         struct nm_softc *pti = tp->t_dev->si_drv1;
 444
 445         if (tp->t_state & TS_TTSTOP)
 446                 return;
 447         pti->pt_flags &= ~PF_STOPPED;
 448         wakeup_other(tp, FREAD);
 449 }
 450
 451 /* Wakes up the OTHER tty;*/
 452 static void
 453 wakeup_other(tp, flag)
 454         struct tty *tp;
 455         int flag;
 456 {
 457         struct softpart *ourpart, *otherpart;
 458
 459         GETPARTS(tp, ourpart, otherpart);
 460         if (flag & FREAD) {
 461                 selwakeup(&otherpart->nm_tty.t_rsel);
 462                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 463         }
 464         if (flag & FWRITE) {
 465                 selwakeup(&otherpart->nm_tty.t_wsel);
 466                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 467         }
 468 }
 469
 470 static  void
 471 nmdmstop(tp, flush)
 472         struct tty *tp;
 473         int flush;
 474 {
 475         struct nm_softc *pti = tp->t_dev->si_drv1;
 476         int flag;
 477
 478         /* note: FLUSHREAD and FLUSHWRITE already ok */
 479         if (flush == 0) {
 480                 flush = TIOCPKT_STOP;
 481                 pti->pt_flags |= PF_STOPPED;
 482         } else
 483                 pti->pt_flags &= ~PF_STOPPED;
 484         /* change of perspective */
 485         flag = 0;
 486         if (flush & FREAD)
 487                 flag |= FWRITE;
 488         if (flush & FWRITE)
 489                 flag |= FREAD;
 490         wakeup_other(tp, flag);
 491 }
 492
 493 /*ARGSUSED*/
 494 static  int
 495 nmdmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
 496 {
 497         struct tty *tp = dev->si_tty;
 498         struct nm_softc *pti = dev->si_drv1;
 499         int error, s;
 500         struct tty *tp2;
 501         struct softpart *ourpart, *otherpart;
 502
 503         s = spltty();
 504         GETPARTS(tp, ourpart, otherpart);
 505         tp2 = &otherpart->nm_tty;
 506
 507         error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, td);
 508         if (error == ENOIOCTL)
 509                  error = ttioctl(tp, cmd, data, flag);
 510         if (error == ENOIOCTL) {
 511                 switch (cmd) {
 512                 case TIOCSBRK:
 513                         otherpart->gotbreak = 1;
 514                         break;
 515                 case TIOCCBRK:
 516                         break;
 517                 case TIOCSDTR:
 518                         ourpart->modemsignals |= TIOCM_DTR;
 519                         break;
 520                 case TIOCCDTR:
 521                         ourpart->modemsignals &= TIOCM_DTR;
 522                         break;
 523                 case TIOCMSET:
 524                         ourpart->modemsignals = *(int *)data;
 525                         otherpart->modemsignals = *(int *)data;
 526                         break;
 527                 case TIOCMBIS:
 528                         ourpart->modemsignals |= *(int *)data;
 529                         break;
 530                 case TIOCMBIC:
 531                         ourpart->modemsignals &= ~(*(int *)data);
 532                         otherpart->modemsignals &= ~(*(int *)data);
 533                         break;
 534                 case TIOCMGET:
 535                         *(int *)data = ourpart->modemsignals;
 536                         break;
 537                 case TIOCMSDTRWAIT:
 538                         break;
 539                 case TIOCMGDTRWAIT:
 540                         *(int *)data = 0;
 541                         break;
 542                 case TIOCTIMESTAMP:
 543                 case TIOCDCDTIMESTAMP:
 544                 default:
 545                         splx(s);
 546                         error = ENOTTY;
 547                         return (error);
 548                 }
 549                 error = 0;
 550                 nmdm_crossover(pti, ourpart, otherpart);
 551         }
 552         splx(s);
 553         return (error);
 554 }
 555
 556 static void
 557 nmdm_crossover(struct nm_softc *pti,
 558                 struct softpart *ourpart,
 559                 struct softpart *otherpart)
 560 {
 561         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 562         if (ourpart->modemsignals & TIOCM_RTS)
 563                 otherpart->modemsignals |= TIOCM_CTS;
 564         if (ourpart->modemsignals & TIOCM_DTR)
 565                 otherpart->modemsignals |= TIOCM_CAR;
 566 }
 567
 568
 569
 570 static void nmdm_drvinit (void *unused);
 571
 572 static void
 573 nmdm_drvinit(unused)
 574         void *unused;
 575 {
 576         /* XXX: Gross hack for DEVFS */
 577         nmdminit(0);
 578 }
 579
 580 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)