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         .d_revoke =     ttyrevoke
  81 };
  82
  83 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
  84
  85 struct softpart {
  86         struct tty nm_tty;
  87         cdev_t  dev;
  88         int     modemsignals;   /* bits defined in sys/ttycom.h */
  89         int     gotbreak;
  90 };
  91
  92 struct  nm_softc {
  93         int     pt_flags;
  94         struct softpart part1, part2;
  95         struct  prison *pt_prison;
  96 };
  97
  98 #define PF_STOPPED      0x10            /* user told stopped */
  99
 100 static void
 101 nmdm_crossover(struct nm_softc *pti,
 102                 struct softpart *ourpart,
 103                 struct softpart *otherpart);
 104
 105 #define GETPARTS(tp, ourpart, otherpart) \
 106 do {    \
 107         struct nm_softc *pti = tp->t_dev->si_drv1; \
 108         if (tp == &pti->part1.nm_tty) { \
 109                 ourpart = &pti->part1; \
 110                 otherpart = &pti->part2; \
 111         } else { \
 112                 ourpart = &pti->part2; \
 113                 otherpart = &pti->part1; \
 114         }  \
 115 } while (0)
 116
 117 /*
 118  * This function creates and initializes a pair of ttys.
 119  */
 120 static void
 121 nmdminit(int n)
 122 {
 123         cdev_t dev1, dev2;
 124         struct nm_softc *pt;
 125
 126         /*
 127          * Simplified unit number, use low 8 bits of minor number
 128          * (remember, the minor number mask is 0xffff00ff).
 129          */
 130         if (n & ~0x7f)
 131                 return;
 132
 133         pt = kmalloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
 134         dev_ops_add(&nmdm_ops, ~1, n << 1);
 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         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 && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
 209                 return (EBUSY);
 210         } else if (pti->pt_prison != ap->a_cred->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(struct dev_close_args *ap)
 260 {
 261         cdev_t dev = ap->a_head.a_dev;
 262         struct tty *tp, *tp2;
 263         int err;
 264         struct softpart *ourpart, *otherpart;
 265
 266         /*
 267          * let the other end know that the game is up
 268          */
 269         tp = dev->si_tty;
 270         GETPARTS(tp, ourpart, otherpart);
 271         tp2 = &otherpart->nm_tty;
 272         (void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
 273
 274         /*
 275          * XXX MDMBUF makes no sense for nmdms but would inhibit the above
 276          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 277          * l_modem()s that ignore carrier drop make no sense for nmdms but
 278          * may be in use because other parts of the line discipline make
 279          * sense for nmdms.  Recover by doing everything that a normal
 280          * ttymodem() would have done except for sending a SIGHUP.
 281          */
 282         if (tp2->t_state & TS_ISOPEN) {
 283                 tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 284                 tp2->t_state |= TS_ZOMBIE;
 285                 ttyflush(tp2, FREAD | FWRITE);
 286         }
 287
 288         err = (*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
 289         ourpart->modemsignals &= ~TIOCM_DTR;
 290         nmdm_crossover(dev->si_drv1, ourpart, otherpart);
 291         nmdmstop(tp, FREAD|FWRITE);
 292         (void) ttyclose(tp);
 293         return (err);
 294 }
 295
 296 static int
 297 nmdmread(struct dev_read_args *ap)
 298 {
 299         cdev_t dev = ap->a_head.a_dev;
 300         int error = 0;
 301         struct tty *tp, *tp2;
 302         struct softpart *ourpart, *otherpart;
 303
 304         tp = dev->si_tty;
 305         GETPARTS(tp, ourpart, otherpart);
 306         tp2 = &otherpart->nm_tty;
 307
 308 #if 0
 309         if (tp2->t_state & TS_ISOPEN) {
 310                 error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
 311                 wakeup_other(tp, FWRITE);
 312         } else {
 313                 if (flag & IO_NDELAY) {
 314                         return (EWOULDBLOCK);
 315                 }
 316                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 317                 }
 318         }
 319 #else
 320         if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
 321                 wakeup_other(tp, FWRITE);
 322 #endif
 323         return (error);
 324 }
 325
 326 /*
 327  * Write to pseudo-tty.
 328  * Wakeups of controlling tty will happen
 329  * indirectly, when tty driver calls nmdmstart.
 330  */
 331 static  int
 332 nmdmwrite(struct dev_write_args *ap)
 333 {
 334         cdev_t dev = ap->a_head.a_dev;
 335         struct uio *uio = ap->a_uio;
 336         u_char *cp = 0;
 337         int cc = 0;
 338         u_char locbuf[BUFSIZ];
 339         int cnt = 0;
 340         int error = 0;
 341         struct tty *tp1, *tp;
 342         struct softpart *ourpart, *otherpart;
 343
 344         tp1 = dev->si_tty;
 345         /*
 346          * Get the other tty struct.
 347          * basically we are writing into the INPUT side of the other device.
 348          */
 349         GETPARTS(tp1, ourpart, otherpart);
 350         tp = &otherpart->nm_tty;
 351
 352 again:
 353         if ((tp->t_state & TS_ISOPEN) == 0)
 354                 return (EIO);
 355         while (uio->uio_resid > 0 || cc > 0) {
 356                 /*
 357                  * Fill up the buffer if it's empty
 358                  */
 359                 if (cc == 0) {
 360                         cc = min(uio->uio_resid, BUFSIZ);
 361                         cp = locbuf;
 362                         error = uiomove((caddr_t)cp, cc, uio);
 363                         if (error)
 364                                 return (error);
 365                         /* check again for safety */
 366                         if ((tp->t_state & TS_ISOPEN) == 0) {
 367                                 /* adjust for data copied in but not written */
 368                                 uio->uio_resid += cc;
 369                                 return (EIO);
 370                         }
 371                 }
 372                 while (cc > 0) {
 373                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 374                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 375                                 /*
 376                                  * Come here to wait for space in outq,
 377                                  * or space in rawq, or an empty canq.
 378                                  */
 379                                 wakeup(TSA_HUP_OR_INPUT(tp));
 380                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 381                                         /*
 382                                          * Data piled up because not connected.
 383                                          * Adjust for data copied in but
 384                                          * not written.
 385                                          */
 386                                         uio->uio_resid += cc;
 387                                         return (EIO);
 388                                 }
 389                                 if (ap->a_ioflag & IO_NDELAY) {
 390                                         /*
 391                                          * Don't wait if asked not to.
 392                                          * Adjust for data copied in but
 393                                          * not written.
 394                                          */
 395                                         uio->uio_resid += cc;
 396                                         if (cnt == 0)
 397                                                 return (EWOULDBLOCK);
 398                                         return (0);
 399                                 }
 400                                 error = tsleep(TSA_PTC_WRITE(tp),
 401                                                 PCATCH, "nmdout", 0);
 402                                 if (error) {
 403                                         /*
 404                                          * Tsleep returned (signal?).
 405                                          * Go find out what the user wants.
 406                                          * adjust for data copied in but
 407                                          * not written
 408                                          */
 409                                         uio->uio_resid += cc;
 410                                         return (error);
 411                                 }
 412                                 goto again;
 413                         }
 414                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 415                         cnt++;
 416                         cc--;
 417                 }
 418                 cc = 0;
 419         }
 420         return (0);
 421 }
 422
 423 /*
 424  * Start output on pseudo-tty.
 425  * Wake up process selecting or sleeping for input from controlling tty.
 426  */
 427 static void
 428 nmdmstart(struct tty *tp)
 429 {
 430         struct nm_softc *pti = tp->t_dev->si_drv1;
 431
 432         if (tp->t_state & TS_TTSTOP)
 433                 return;
 434         pti->pt_flags &= ~PF_STOPPED;
 435         wakeup_other(tp, FREAD);
 436 }
 437
 438 /* Wakes up the OTHER tty;*/
 439 static void
 440 wakeup_other(struct tty *tp, int flag)
 441 {
 442         struct softpart *ourpart, *otherpart;
 443
 444         GETPARTS(tp, ourpart, otherpart);
 445         if (flag & FREAD) {
 446                 selwakeup(&otherpart->nm_tty.t_rsel);
 447                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 448         }
 449         if (flag & FWRITE) {
 450                 selwakeup(&otherpart->nm_tty.t_wsel);
 451                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 452         }
 453 }
 454
 455 static  void
 456 nmdmstop(struct tty *tp, int flush)
 457 {
 458         struct nm_softc *pti = tp->t_dev->si_drv1;
 459         int flag;
 460
 461         /* note: FLUSHREAD and FLUSHWRITE already ok */
 462         if (flush == 0) {
 463                 flush = TIOCPKT_STOP;
 464                 pti->pt_flags |= PF_STOPPED;
 465         } else
 466                 pti->pt_flags &= ~PF_STOPPED;
 467         /* change of perspective */
 468         flag = 0;
 469         if (flush & FREAD)
 470                 flag |= FWRITE;
 471         if (flush & FWRITE)
 472                 flag |= FREAD;
 473         wakeup_other(tp, flag);
 474 }
 475
 476 /*ARGSUSED*/
 477 static  int
 478 nmdmioctl(struct dev_ioctl_args *ap)
 479 {
 480         cdev_t dev = ap->a_head.a_dev;
 481         struct tty *tp = dev->si_tty;
 482         struct nm_softc *pti = dev->si_drv1;
 483         int error;
 484         struct tty *tp2;
 485         struct softpart *ourpart, *otherpart;
 486
 487         crit_enter();
 488         GETPARTS(tp, ourpart, otherpart);
 489         tp2 = &otherpart->nm_tty;
 490
 491         error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
 492                                               ap->a_fflag, ap->a_cred);
 493         if (error == ENOIOCTL)
 494                  error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
 495         if (error == ENOIOCTL) {
 496                 switch (ap->a_cmd) {
 497                 case TIOCSBRK:
 498                         otherpart->gotbreak = 1;
 499                         break;
 500                 case TIOCCBRK:
 501                         break;
 502                 case TIOCSDTR:
 503                         ourpart->modemsignals |= TIOCM_DTR;
 504                         break;
 505                 case TIOCCDTR:
 506                         ourpart->modemsignals &= TIOCM_DTR;
 507                         break;
 508                 case TIOCMSET:
 509                         ourpart->modemsignals = *(int *)ap->a_data;
 510                         otherpart->modemsignals = *(int *)ap->a_data;
 511                         break;
 512                 case TIOCMBIS:
 513                         ourpart->modemsignals |= *(int *)ap->a_data;
 514                         break;
 515                 case TIOCMBIC:
 516                         ourpart->modemsignals &= ~(*(int *)ap->a_data);
 517                         otherpart->modemsignals &= ~(*(int *)ap->a_data);
 518                         break;
 519                 case TIOCMGET:
 520                         *(int *)ap->a_data = ourpart->modemsignals;
 521                         break;
 522                 case TIOCMSDTRWAIT:
 523                         break;
 524                 case TIOCMGDTRWAIT:
 525                         *(int *)ap->a_data = 0;
 526                         break;
 527                 case TIOCTIMESTAMP:
 528                 case TIOCDCDTIMESTAMP:
 529                 default:
 530                         crit_exit();
 531                         error = ENOTTY;
 532                         return (error);
 533                 }
 534                 error = 0;
 535                 nmdm_crossover(pti, ourpart, otherpart);
 536         }
 537         crit_exit();
 538         return (error);
 539 }
 540
 541 static void
 542 nmdm_crossover(struct nm_softc *pti,
 543                 struct softpart *ourpart,
 544                 struct softpart *otherpart)
 545 {
 546         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 547         if (ourpart->modemsignals & TIOCM_RTS)
 548                 otherpart->modemsignals |= TIOCM_CTS;
 549         if (ourpart->modemsignals & TIOCM_DTR)
 550                 otherpart->modemsignals |= TIOCM_CAR;
 551 }
 552
 553
 554
 555 static void nmdm_drvinit (void *unused);
 556
 557 static void
 558 nmdm_drvinit(void *unused)
 559 {
 560         /* XXX: Gross hack for DEVFS */
 561         nmdminit(0);
 562 }
 563
 564 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)