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 1.16 2008/01/05 14:02:37 swildner 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/priv.h>
  48 #include <sys/thread2.h>
  49 #include <sys/tty.h>
  50 #include <sys/conf.h>
  51 #include <sys/fcntl.h>
  52 #include <sys/poll.h>
  53 #include <sys/kernel.h>
  54 #include <sys/vnode.h>
  55 #include <sys/signalvar.h>
  56 #include <sys/malloc.h>
  57
  58 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
  59
  60 static void nmdmstart (struct tty *tp);
  61 static void nmdmstop (struct tty *tp, int rw);
  62 static void wakeup_other (struct tty *tp, int flag);
  63 static void nmdminit (int n);
  64
  65 static  d_open_t        nmdmopen;
  66 static  d_close_t       nmdmclose;
  67 static  d_read_t        nmdmread;
  68 static  d_write_t       nmdmwrite;
  69 static  d_ioctl_t       nmdmioctl;
  70
  71 #define CDEV_MAJOR      18
  72 static struct dev_ops nmdm_ops = {
  73         { "pts", CDEV_MAJOR, D_TTY },
  74         .d_open =       nmdmopen,
  75         .d_close =      nmdmclose,
  76         .d_read =       nmdmread,
  77         .d_write =      nmdmwrite,
  78         .d_ioctl =      nmdmioctl,
  79         .d_poll =       ttypoll,
  80 };
  81
  82 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
  83
  84 struct softpart {
  85         struct tty nm_tty;
  86         cdev_t  dev;
  87         int     modemsignals;   /* bits defined in sys/ttycom.h */
  88         int     gotbreak;
  89 };
  90
  91 struct  nm_softc {
  92         int     pt_flags;
  93         struct softpart part1, part2;
  94         struct  prison *pt_prison;
  95 };
  96
  97 #define PF_STOPPED      0x10            /* user told stopped */
  98
  99 static void
 100 nmdm_crossover(struct nm_softc *pti,
 101                 struct softpart *ourpart,
 102                 struct softpart *otherpart);
 103
 104 #define GETPARTS(tp, ourpart, otherpart) \
 105 do {    \
 106         struct nm_softc *pti = tp->t_dev->si_drv1; \
 107         if (tp == &pti->part1.nm_tty) { \
 108                 ourpart = &pti->part1; \
 109                 otherpart = &pti->part2; \
 110         } else { \
 111                 ourpart = &pti->part2; \
 112                 otherpart = &pti->part1; \
 113         }  \
 114 } while (0)
 115
 116 /*
 117  * This function creates and initializes a pair of ttys.
 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         pt = kmalloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
 133         dev_ops_add(&nmdm_ops, ~1, n << 1);
 134         pt->part1.dev = dev1 = make_dev(&nmdm_ops, n << 1,
 135             0, 0, 0666, "nmdm%dA", n);
 136         pt->part2.dev = dev2 = make_dev(&nmdm_ops, (n << 1) + 1,
 137             0, 0, 0666, "nmdm%dB", n);
 138
 139         dev1->si_drv1 = dev2->si_drv1 = pt;
 140         dev1->si_tty = &pt->part1.nm_tty;
 141         dev2->si_tty = &pt->part2.nm_tty;
 142         ttyregister(&pt->part1.nm_tty);
 143         ttyregister(&pt->part2.nm_tty);
 144         pt->part1.nm_tty.t_oproc = nmdmstart;
 145         pt->part2.nm_tty.t_oproc = nmdmstart;
 146         pt->part1.nm_tty.t_stop = nmdmstop;
 147         pt->part2.nm_tty.t_dev = dev1;
 148         pt->part1.nm_tty.t_dev = dev2;
 149         pt->part2.nm_tty.t_stop = nmdmstop;
 150 }
 151
 152 /*ARGSUSED*/
 153 static  int
 154 nmdmopen(struct dev_open_args *ap)
 155 {
 156         cdev_t dev = ap->a_head.a_dev;
 157         struct tty *tp, *tp2;
 158         int error;
 159         int minr;
 160 #if 0
 161         cdev_t nextdev;
 162 #endif
 163         struct nm_softc *pti;
 164         int is_b;
 165         int     pair;
 166         struct  softpart *ourpart, *otherpart;
 167
 168         minr = lminor(dev);
 169         pair = minr >> 1;
 170         is_b = minr & 1;
 171
 172 #if 0
 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         if (pair < 127) {
 179                 nextdev = makedev(major(dev), (pair+pair) + 1);
 180                 if (!nextdev->si_drv1) {
 181                         nmdminit(pair + 1);
 182                 }
 183         }
 184 #endif
 185         if (!dev->si_drv1)
 186                 nmdminit(pair);
 187
 188         if (!dev->si_drv1)
 189                 return(ENXIO);
 190
 191         pti = dev->si_drv1;
 192         if (is_b)
 193                 tp = &pti->part2.nm_tty;
 194         else
 195                 tp = &pti->part1.nm_tty;
 196         GETPARTS(tp, ourpart, otherpart);
 197         tp2 = &otherpart->nm_tty;
 198         ourpart->modemsignals |= TIOCM_LE;
 199
 200         if ((tp->t_state & TS_ISOPEN) == 0) {
 201                 ttychars(tp);           /* Set up default chars */
 202                 tp->t_iflag = TTYDEF_IFLAG;
 203                 tp->t_oflag = TTYDEF_OFLAG;
 204                 tp->t_lflag = TTYDEF_LFLAG;
 205                 tp->t_cflag = TTYDEF_CFLAG;
 206                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 207         } else if (tp->t_state & TS_XCLUDE && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
 208                 return (EBUSY);
 209         } else if (pti->pt_prison != ap->a_cred->cr_prison) {
 210                 return (EBUSY);
 211         }
 212
 213         /*
 214          * If the other side is open we have carrier
 215          */
 216         if (tp2->t_state & TS_ISOPEN) {
 217                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 218         }
 219
 220         /*
 221          * And the other side gets carrier as we are now open.
 222          */
 223         (void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
 224
 225         /* External processing makes no sense here */
 226         tp->t_lflag &= ~EXTPROC;
 227
 228         /*
 229          * Wait here if we don't have carrier.
 230          */
 231 #if 0
 232         while ((tp->t_state & TS_CARR_ON) == 0) {
 233                 if (flag & FNONBLOCK)
 234                         break;
 235                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
 236                 if (error)
 237                         return (error);
 238         }
 239 #endif
 240
 241         /*
 242          * Give the line disciplin a chance to set this end up.
 243          */
 244         error = (*linesw[tp->t_line].l_open)(dev, tp);
 245
 246         /*
 247          * Wake up the other side.
 248          * Theoretically not needed.
 249          */
 250         ourpart->modemsignals |= TIOCM_DTR;
 251         nmdm_crossover(pti, ourpart, otherpart);
 252         if (error == 0)
 253                 wakeup_other(tp, FREAD|FWRITE); /* XXX */
 254         return (error);
 255 }
 256
 257 static int
 258 nmdmclose(struct dev_close_args *ap)
 259 {
 260         cdev_t dev = ap->a_head.a_dev;
 261         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, ap->a_fflag);
 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(struct dev_read_args *ap)
 297 {
 298         cdev_t dev = ap->a_head.a_dev;
 299         int error = 0;
 300         struct tty *tp, *tp2;
 301         struct softpart *ourpart, *otherpart;
 302
 303         tp = dev->si_tty;
 304         GETPARTS(tp, ourpart, otherpart);
 305         tp2 = &otherpart->nm_tty;
 306
 307 #if 0
 308         if (tp2->t_state & TS_ISOPEN) {
 309                 error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
 310                 wakeup_other(tp, FWRITE);
 311         } else {
 312                 if (flag & IO_NDELAY) {
 313                         return (EWOULDBLOCK);
 314                 }
 315                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 316                 }
 317         }
 318 #else
 319         if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
 320                 wakeup_other(tp, FWRITE);
 321 #endif
 322         return (error);
 323 }
 324
 325 /*
 326  * Write to pseudo-tty.
 327  * Wakeups of controlling tty will happen
 328  * indirectly, when tty driver calls nmdmstart.
 329  */
 330 static  int
 331 nmdmwrite(struct dev_write_args *ap)
 332 {
 333         cdev_t dev = ap->a_head.a_dev;
 334         struct uio *uio = ap->a_uio;
 335         u_char *cp = 0;
 336         int cc = 0;
 337         u_char locbuf[BUFSIZ];
 338         int cnt = 0;
 339         int error = 0;
 340         struct tty *tp1, *tp;
 341         struct softpart *ourpart, *otherpart;
 342
 343         tp1 = dev->si_tty;
 344         /*
 345          * Get the other tty struct.
 346          * basically we are writing into the INPUT side of the other device.
 347          */
 348         GETPARTS(tp1, ourpart, otherpart);
 349         tp = &otherpart->nm_tty;
 350
 351 again:
 352         if ((tp->t_state & TS_ISOPEN) == 0)
 353                 return (EIO);
 354         while (uio->uio_resid > 0 || cc > 0) {
 355                 /*
 356                  * Fill up the buffer if it's empty
 357                  */
 358                 if (cc == 0) {
 359                         cc = min(uio->uio_resid, BUFSIZ);
 360                         cp = locbuf;
 361                         error = uiomove((caddr_t)cp, cc, uio);
 362                         if (error)
 363                                 return (error);
 364                         /* check again for safety */
 365                         if ((tp->t_state & TS_ISOPEN) == 0) {
 366                                 /* adjust for data copied in but not written */
 367                                 uio->uio_resid += cc;
 368                                 return (EIO);
 369                         }
 370                 }
 371                 while (cc > 0) {
 372                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 373                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 374                                 /*
 375                                  * Come here to wait for space in outq,
 376                                  * or space in rawq, or an empty canq.
 377                                  */
 378                                 wakeup(TSA_HUP_OR_INPUT(tp));
 379                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 380                                         /*
 381                                          * Data piled up because not connected.
 382                                          * Adjust for data copied in but
 383                                          * not written.
 384                                          */
 385                                         uio->uio_resid += cc;
 386                                         return (EIO);
 387                                 }
 388                                 if (ap->a_ioflag & IO_NDELAY) {
 389                                         /*
 390                                          * Don't wait if asked not to.
 391                                          * Adjust for data copied in but
 392                                          * not written.
 393                                          */
 394                                         uio->uio_resid += cc;
 395                                         if (cnt == 0)
 396                                                 return (EWOULDBLOCK);
 397                                         return (0);
 398                                 }
 399                                 error = tsleep(TSA_PTC_WRITE(tp),
 400                                                 PCATCH, "nmdout", 0);
 401                                 if (error) {
 402                                         /*
 403                                          * Tsleep returned (signal?).
 404                                          * Go find out what the user wants.
 405                                          * adjust for data copied in but
 406                                          * not written
 407                                          */
 408                                         uio->uio_resid += cc;
 409                                         return (error);
 410                                 }
 411                                 goto again;
 412                         }
 413                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 414                         cnt++;
 415                         cc--;
 416                 }
 417                 cc = 0;
 418         }
 419         return (0);
 420 }
 421
 422 /*
 423  * Start output on pseudo-tty.
 424  * Wake up process selecting or sleeping for input from controlling tty.
 425  */
 426 static void
 427 nmdmstart(struct tty *tp)
 428 {
 429         struct nm_softc *pti = tp->t_dev->si_drv1;
 430
 431         if (tp->t_state & TS_TTSTOP)
 432                 return;
 433         pti->pt_flags &= ~PF_STOPPED;
 434         wakeup_other(tp, FREAD);
 435 }
 436
 437 /* Wakes up the OTHER tty;*/
 438 static void
 439 wakeup_other(struct tty *tp, int flag)
 440 {
 441         struct softpart *ourpart, *otherpart;
 442
 443         GETPARTS(tp, ourpart, otherpart);
 444         if (flag & FREAD) {
 445                 selwakeup(&otherpart->nm_tty.t_rsel);
 446                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 447         }
 448         if (flag & FWRITE) {
 449                 selwakeup(&otherpart->nm_tty.t_wsel);
 450                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 451         }
 452 }
 453
 454 static  void
 455 nmdmstop(struct tty *tp, int flush)
 456 {
 457         struct nm_softc *pti = tp->t_dev->si_drv1;
 458         int flag;
 459
 460         /* note: FLUSHREAD and FLUSHWRITE already ok */
 461         if (flush == 0) {
 462                 flush = TIOCPKT_STOP;
 463                 pti->pt_flags |= PF_STOPPED;
 464         } else
 465                 pti->pt_flags &= ~PF_STOPPED;
 466         /* change of perspective */
 467         flag = 0;
 468         if (flush & FREAD)
 469                 flag |= FWRITE;
 470         if (flush & FWRITE)
 471                 flag |= FREAD;
 472         wakeup_other(tp, flag);
 473 }
 474
 475 /*ARGSUSED*/
 476 static  int
 477 nmdmioctl(struct dev_ioctl_args *ap)
 478 {
 479         cdev_t dev = ap->a_head.a_dev;
 480         struct tty *tp = dev->si_tty;
 481         struct nm_softc *pti = dev->si_drv1;
 482         int error;
 483         struct tty *tp2;
 484         struct softpart *ourpart, *otherpart;
 485
 486         crit_enter();
 487         GETPARTS(tp, ourpart, otherpart);
 488         tp2 = &otherpart->nm_tty;
 489
 490         error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
 491                                               ap->a_fflag, ap->a_cred);
 492         if (error == ENOIOCTL)
 493                  error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
 494         if (error == ENOIOCTL) {
 495                 switch (ap->a_cmd) {
 496                 case TIOCSBRK:
 497                         otherpart->gotbreak = 1;
 498                         break;
 499                 case TIOCCBRK:
 500                         break;
 501                 case TIOCSDTR:
 502                         ourpart->modemsignals |= TIOCM_DTR;
 503                         break;
 504                 case TIOCCDTR:
 505                         ourpart->modemsignals &= TIOCM_DTR;
 506                         break;
 507                 case TIOCMSET:
 508                         ourpart->modemsignals = *(int *)ap->a_data;
 509                         otherpart->modemsignals = *(int *)ap->a_data;
 510                         break;
 511                 case TIOCMBIS:
 512                         ourpart->modemsignals |= *(int *)ap->a_data;
 513                         break;
 514                 case TIOCMBIC:
 515                         ourpart->modemsignals &= ~(*(int *)ap->a_data);
 516                         otherpart->modemsignals &= ~(*(int *)ap->a_data);
 517                         break;
 518                 case TIOCMGET:
 519                         *(int *)ap->a_data = ourpart->modemsignals;
 520                         break;
 521                 case TIOCMSDTRWAIT:
 522                         break;
 523                 case TIOCMGDTRWAIT:
 524                         *(int *)ap->a_data = 0;
 525                         break;
 526                 case TIOCTIMESTAMP:
 527                 case TIOCDCDTIMESTAMP:
 528                 default:
 529                         crit_exit();
 530                         error = ENOTTY;
 531                         return (error);
 532                 }
 533                 error = 0;
 534                 nmdm_crossover(pti, ourpart, otherpart);
 535         }
 536         crit_exit();
 537         return (error);
 538 }
 539
 540 static void
 541 nmdm_crossover(struct nm_softc *pti,
 542                 struct softpart *ourpart,
 543                 struct softpart *otherpart)
 544 {
 545         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 546         if (ourpart->modemsignals & TIOCM_RTS)
 547                 otherpart->modemsignals |= TIOCM_CTS;
 548         if (ourpart->modemsignals & TIOCM_DTR)
 549                 otherpart->modemsignals |= TIOCM_CAR;
 550 }
 551
 552
 553
 554 static void nmdm_drvinit (void *unused);
 555
 556 static void
 557 nmdm_drvinit(void *unused)
 558 {
 559         /* XXX: Gross hack for DEVFS */
 560         nmdminit(0);
 561 }
 562
 563 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)