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 1.7 2003/07/26 14:25:23 rob 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         /* name */      "pts",
  72         /* maj */       CDEV_MAJOR,
  73         /* flags */     D_TTY,
  74         /* port */      NULL,
  75         /* autoq */     0,
  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         /* For now we only map the lower 8 bits of the minor */
 134         if (n & ~0xff)
 135                 return;
 136
 137         pt = malloc(sizeof(*pt), M_NLMDM, M_WAITOK);
 138         bzero(pt, sizeof(*pt));
 139         pt->part1.dev = dev1 = make_dev(&nmdm_cdevsw, n+n,
 140             0, 0, 0666, "nmdm%dA", n);
 141         pt->part2.dev = dev2 = make_dev(&nmdm_cdevsw, n+n+1,
 142             0, 0, 0666, "nmdm%dB", n);
 143
 144         dev1->si_drv1 = dev2->si_drv1 = pt;
 145         dev1->si_tty = &pt->part1.nm_tty;
 146         dev2->si_tty = &pt->part2.nm_tty;
 147         ttyregister(&pt->part1.nm_tty);
 148         ttyregister(&pt->part2.nm_tty);
 149         pt->part1.nm_tty.t_oproc = nmdmstart;
 150         pt->part2.nm_tty.t_oproc = nmdmstart;
 151         pt->part1.nm_tty.t_stop = nmdmstop;
 152         pt->part2.nm_tty.t_dev = dev1;
 153         pt->part1.nm_tty.t_dev = dev2;
 154         pt->part2.nm_tty.t_stop = nmdmstop;
 155 }
 156
 157 /*ARGSUSED*/
 158 static  int
 159 nmdmopen(dev_t dev, int flag, int devtype, struct thread *td)
 160 {
 161         struct proc *p = td->td_proc;
 162         struct tty *tp, *tp2;
 163         int error;
 164         int minr;
 165         dev_t nextdev;
 166         struct nm_softc *pti;
 167         int is_b;
 168         int     pair;
 169         struct  softpart *ourpart, *otherpart;
 170
 171         KKASSERT(p != NULL);
 172
 173         /*
 174          * XXX: Gross hack for DEVFS:
 175          * If we openned this device, ensure we have the
 176          * next one too, so people can open it.
 177          */
 178         minr = lminor(dev);
 179         pair = minr >> 1;
 180         is_b = minr & 1;
 181
 182         if (pair < 127) {
 183                 nextdev = makedev(major(dev), (pair+pair) + 1);
 184                 if (!nextdev->si_drv1) {
 185                         nmdminit(pair + 1);
 186                 }
 187         }
 188         if (!dev->si_drv1)
 189                 nmdminit(pair);
 190
 191         if (!dev->si_drv1)
 192                 return(ENXIO);
 193
 194         pti = dev->si_drv1;
 195         if (is_b)
 196                 tp = &pti->part2.nm_tty;
 197         else
 198                 tp = &pti->part1.nm_tty;
 199         GETPARTS(tp, ourpart, otherpart);
 200         tp2 = &otherpart->nm_tty;
 201         ourpart->modemsignals |= TIOCM_LE;
 202
 203         if ((tp->t_state & TS_ISOPEN) == 0) {
 204                 ttychars(tp);           /* Set up default chars */
 205                 tp->t_iflag = TTYDEF_IFLAG;
 206                 tp->t_oflag = TTYDEF_OFLAG;
 207                 tp->t_lflag = TTYDEF_LFLAG;
 208                 tp->t_cflag = TTYDEF_CFLAG;
 209                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 210         } else if (tp->t_state & TS_XCLUDE && suser(td)) {
 211                 return (EBUSY);
 212         } else if (pti->pt_prison != p->p_ucred->cr_prison) {
 213                 return (EBUSY);
 214         }
 215
 216         /*
 217          * If the other side is open we have carrier
 218          */
 219         if (tp2->t_state & TS_ISOPEN) {
 220                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 221         }
 222
 223         /*
 224          * And the other side gets carrier as we are now open.
 225          */
 226         (void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
 227
 228         /* External processing makes no sense here */
 229         tp->t_lflag &= ~EXTPROC;
 230
 231         /*
 232          * Wait here if we don't have carrier.
 233          */
 234 #if 0
 235         while ((tp->t_state & TS_CARR_ON) == 0) {
 236                 if (flag & FNONBLOCK)
 237                         break;
 238                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
 239                 if (error)
 240                         return (error);
 241         }
 242 #endif
 243
 244         /*
 245          * Give the line disciplin a chance to set this end up.
 246          */
 247         error = (*linesw[tp->t_line].l_open)(dev, tp);
 248
 249         /*
 250          * Wake up the other side.
 251          * Theoretically not needed.
 252          */
 253         ourpart->modemsignals |= TIOCM_DTR;
 254         nmdm_crossover(pti, ourpart, otherpart);
 255         if (error == 0)
 256                 wakeup_other(tp, FREAD|FWRITE); /* XXX */
 257         return (error);
 258 }
 259
 260 static  int
 261 nmdmclose(dev_t dev, int flag, int mode, struct thread *td)
 262 {
 263         struct tty *tp, *tp2;
 264         int err;
 265         struct softpart *ourpart, *otherpart;
 266
 267         /*
 268          * let the other end know that the game is up
 269          */
 270         tp = dev->si_tty;
 271         GETPARTS(tp, ourpart, otherpart);
 272         tp2 = &otherpart->nm_tty;
 273         (void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
 274
 275         /*
 276          * XXX MDMBUF makes no sense for nmdms but would inhibit the above
 277          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 278          * l_modem()s that ignore carrier drop make no sense for nmdms but
 279          * may be in use because other parts of the line discipline make
 280          * sense for nmdms.  Recover by doing everything that a normal
 281          * ttymodem() would have done except for sending a SIGHUP.
 282          */
 283         if (tp2->t_state & TS_ISOPEN) {
 284                 tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 285                 tp2->t_state |= TS_ZOMBIE;
 286                 ttyflush(tp2, FREAD | FWRITE);
 287         }
 288
 289         err = (*linesw[tp->t_line].l_close)(tp, flag);
 290         ourpart->modemsignals &= ~TIOCM_DTR;
 291         nmdm_crossover(dev->si_drv1, ourpart, otherpart);
 292         nmdmstop(tp, FREAD|FWRITE);
 293         (void) ttyclose(tp);
 294         return (err);
 295 }
 296
 297 static  int
 298 nmdmread(dev, uio, flag)
 299         dev_t dev;
 300         struct uio *uio;
 301         int flag;
 302 {
 303         int error = 0;
 304         struct tty *tp, *tp2;
 305         struct softpart *ourpart, *otherpart;
 306
 307         tp = dev->si_tty;
 308         GETPARTS(tp, ourpart, otherpart);
 309         tp2 = &otherpart->nm_tty;
 310
 311 #if 0
 312         if (tp2->t_state & TS_ISOPEN) {
 313                 error = (*linesw[tp->t_line].l_read)(tp, uio, flag);
 314                 wakeup_other(tp, FWRITE);
 315         } else {
 316                 if (flag & IO_NDELAY) {
 317                         return (EWOULDBLOCK);
 318                 }
 319                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 320                 }
 321         }
 322 #else
 323         if ((error = (*linesw[tp->t_line].l_read)(tp, uio, flag)) == 0)
 324                 wakeup_other(tp, FWRITE);
 325 #endif
 326         return (error);
 327 }
 328
 329 /*
 330  * Write to pseudo-tty.
 331  * Wakeups of controlling tty will happen
 332  * indirectly, when tty driver calls nmdmstart.
 333  */
 334 static  int
 335 nmdmwrite(dev, uio, flag)
 336         dev_t dev;
 337         struct uio *uio;
 338         int flag;
 339 {
 340         u_char *cp = 0;
 341         int cc = 0;
 342         u_char locbuf[BUFSIZ];
 343         int cnt = 0;
 344         int error = 0;
 345         struct tty *tp1, *tp;
 346         struct softpart *ourpart, *otherpart;
 347
 348         tp1 = dev->si_tty;
 349         /*
 350          * Get the other tty struct.
 351          * basically we are writing into the INPUT side of the other device.
 352          */
 353         GETPARTS(tp1, ourpart, otherpart);
 354         tp = &otherpart->nm_tty;
 355
 356 again:
 357         if ((tp->t_state & TS_ISOPEN) == 0)
 358                 return (EIO);
 359         while (uio->uio_resid > 0 || cc > 0) {
 360                 /*
 361                  * Fill up the buffer if it's empty
 362                  */
 363                 if (cc == 0) {
 364                         cc = min(uio->uio_resid, BUFSIZ);
 365                         cp = locbuf;
 366                         error = uiomove((caddr_t)cp, cc, uio);
 367                         if (error)
 368                                 return (error);
 369                         /* check again for safety */
 370                         if ((tp->t_state & TS_ISOPEN) == 0) {
 371                                 /* adjust for data copied in but not written */
 372                                 uio->uio_resid += cc;
 373                                 return (EIO);
 374                         }
 375                 }
 376                 while (cc > 0) {
 377                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 378                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 379                                 /*
 380                                  * Come here to wait for space in outq,
 381                                  * or space in rawq, or an empty canq.
 382                                  */
 383                                 wakeup(TSA_HUP_OR_INPUT(tp));
 384                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 385                                         /*
 386                                          * Data piled up because not connected.
 387                                          * Adjust for data copied in but
 388                                          * not written.
 389                                          */
 390                                         uio->uio_resid += cc;
 391                                         return (EIO);
 392                                 }
 393                                 if (flag & IO_NDELAY) {
 394                                         /*
 395                                          * Don't wait if asked not to.
 396                                          * Adjust for data copied in but
 397                                          * not written.
 398                                          */
 399                                         uio->uio_resid += cc;
 400                                         if (cnt == 0)
 401                                                 return (EWOULDBLOCK);
 402                                         return (0);
 403                                 }
 404                                 error = tsleep(TSA_PTC_WRITE(tp),
 405                                                 PCATCH, "nmdout", 0);
 406                                 if (error) {
 407                                         /*
 408                                          * Tsleep returned (signal?).
 409                                          * Go find out what the user wants.
 410                                          * adjust for data copied in but
 411                                          * not written
 412                                          */
 413                                         uio->uio_resid += cc;
 414                                         return (error);
 415                                 }
 416                                 goto again;
 417                         }
 418                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 419                         cnt++;
 420                         cc--;
 421                 }
 422                 cc = 0;
 423         }
 424         return (0);
 425 }
 426
 427 /*
 428  * Start output on pseudo-tty.
 429  * Wake up process selecting or sleeping for input from controlling tty.
 430  */
 431 static void
 432 nmdmstart(tp)
 433         struct tty *tp;
 434 {
 435         struct nm_softc *pti = tp->t_dev->si_drv1;
 436
 437         if (tp->t_state & TS_TTSTOP)
 438                 return;
 439         pti->pt_flags &= ~PF_STOPPED;
 440         wakeup_other(tp, FREAD);
 441 }
 442
 443 /* Wakes up the OTHER tty;*/
 444 static void
 445 wakeup_other(tp, flag)
 446         struct tty *tp;
 447         int flag;
 448 {
 449         struct softpart *ourpart, *otherpart;
 450
 451         GETPARTS(tp, ourpart, otherpart);
 452         if (flag & FREAD) {
 453                 selwakeup(&otherpart->nm_tty.t_rsel);
 454                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 455         }
 456         if (flag & FWRITE) {
 457                 selwakeup(&otherpart->nm_tty.t_wsel);
 458                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 459         }
 460 }
 461
 462 static  void
 463 nmdmstop(tp, flush)
 464         struct tty *tp;
 465         int flush;
 466 {
 467         struct nm_softc *pti = tp->t_dev->si_drv1;
 468         int flag;
 469
 470         /* note: FLUSHREAD and FLUSHWRITE already ok */
 471         if (flush == 0) {
 472                 flush = TIOCPKT_STOP;
 473                 pti->pt_flags |= PF_STOPPED;
 474         } else
 475                 pti->pt_flags &= ~PF_STOPPED;
 476         /* change of perspective */
 477         flag = 0;
 478         if (flush & FREAD)
 479                 flag |= FWRITE;
 480         if (flush & FWRITE)
 481                 flag |= FREAD;
 482         wakeup_other(tp, flag);
 483 }
 484
 485 /*ARGSUSED*/
 486 static  int
 487 nmdmioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
 488 {
 489         struct tty *tp = dev->si_tty;
 490         struct nm_softc *pti = dev->si_drv1;
 491         int error, s;
 492         struct tty *tp2;
 493         struct softpart *ourpart, *otherpart;
 494
 495         s = spltty();
 496         GETPARTS(tp, ourpart, otherpart);
 497         tp2 = &otherpart->nm_tty;
 498
 499         error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, td);
 500         if (error == ENOIOCTL)
 501                  error = ttioctl(tp, cmd, data, flag);
 502         if (error == ENOIOCTL) {
 503                 switch (cmd) {
 504                 case TIOCSBRK:
 505                         otherpart->gotbreak = 1;
 506                         break;
 507                 case TIOCCBRK:
 508                         break;
 509                 case TIOCSDTR:
 510                         ourpart->modemsignals |= TIOCM_DTR;
 511                         break;
 512                 case TIOCCDTR:
 513                         ourpart->modemsignals &= TIOCM_DTR;
 514                         break;
 515                 case TIOCMSET:
 516                         ourpart->modemsignals = *(int *)data;
 517                         otherpart->modemsignals = *(int *)data;
 518                         break;
 519                 case TIOCMBIS:
 520                         ourpart->modemsignals |= *(int *)data;
 521                         break;
 522                 case TIOCMBIC:
 523                         ourpart->modemsignals &= ~(*(int *)data);
 524                         otherpart->modemsignals &= ~(*(int *)data);
 525                         break;
 526                 case TIOCMGET:
 527                         *(int *)data = ourpart->modemsignals;
 528                         break;
 529                 case TIOCMSDTRWAIT:
 530                         break;
 531                 case TIOCMGDTRWAIT:
 532                         *(int *)data = 0;
 533                         break;
 534                 case TIOCTIMESTAMP:
 535                 case TIOCDCDTIMESTAMP:
 536                 default:
 537                         splx(s);
 538                         error = ENOTTY;
 539                         return (error);
 540                 }
 541                 error = 0;
 542                 nmdm_crossover(pti, ourpart, otherpart);
 543         }
 544         splx(s);
 545         return (error);
 546 }
 547
 548 static void
 549 nmdm_crossover(struct nm_softc *pti,
 550                 struct softpart *ourpart,
 551                 struct softpart *otherpart)
 552 {
 553         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 554         if (ourpart->modemsignals & TIOCM_RTS)
 555                 otherpart->modemsignals |= TIOCM_CTS;
 556         if (ourpart->modemsignals & TIOCM_DTR)
 557                 otherpart->modemsignals |= TIOCM_CAR;
 558 }
 559
 560
 561
 562 static void nmdm_drvinit __P((void *unused));
 563
 564 static void
 565 nmdm_drvinit(unused)
 566         void *unused;
 567 {
 568         cdevsw_add(&nmdm_cdevsw);
 569         /* XXX: Gross hack for DEVFS */
 570         nmdminit(0);
 571 }
 572
 573 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)