sys/dev/misc/nmdm/nmdm.c

   1 /*
   2  * (MPSAFE)
   3  *
   4  * Copyright (c) 1982, 1986, 1989, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by the University of
  18  *      California, Berkeley and its contributors.
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * $FreeBSD: src/sys/dev/nmdm/nmdm.c,v 1.5.2.1 2001/08/11 00:54:14 mp Exp $
  36  */
  37
  38 /*
  39  * MPSAFE NOTE: This file acquires the tty_token mainly for linesw access and
  40  *              tp (struct tty) access.
  41  */
  42
  43 /*
  44  * Pseudo-nulmodem Driver
  45  */
  46 #include "opt_compat.h"
  47 #include <sys/param.h>
  48 #include <sys/systm.h>
  49 #if defined(COMPAT_43)
  50 #include <sys/ioctl_compat.h>
  51 #endif
  52 #include <sys/proc.h>
  53 #include <sys/priv.h>
  54 #include <sys/thread2.h>
  55 #include <sys/tty.h>
  56 #include <sys/conf.h>
  57 #include <sys/fcntl.h>
  58 #include <sys/kernel.h>
  59 #include <sys/vnode.h>
  60 #include <sys/signalvar.h>
  61 #include <sys/malloc.h>
  62
  63 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
  64
  65 static void nmdmstart (struct tty *tp);
  66 static void nmdmstop (struct tty *tp, int rw);
  67 static void wakeup_other (struct tty *tp, int flag);
  68 static void nmdminit (int n);
  69
  70 static  d_open_t        nmdmopen;
  71 static  d_close_t       nmdmclose;
  72 static  d_read_t        nmdmread;
  73 static  d_write_t       nmdmwrite;
  74 static  d_ioctl_t       nmdmioctl;
  75
  76 #define CDEV_MAJOR      18
  77 static struct dev_ops nmdm_ops = {
  78         { "pts", 0, D_TTY },
  79         .d_open =       nmdmopen,
  80         .d_close =      nmdmclose,
  81         .d_read =       nmdmread,
  82         .d_write =      nmdmwrite,
  83         .d_ioctl =      nmdmioctl,
  84         .d_kqfilter =   ttykqfilter,
  85         .d_revoke =     ttyrevoke
  86 };
  87
  88 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
  89
  90 struct softpart {
  91         struct tty nm_tty;
  92         cdev_t  dev;
  93         int     modemsignals;   /* bits defined in sys/ttycom.h */
  94         int     gotbreak;
  95 };
  96
  97 struct  nm_softc {
  98         int     pt_flags;
  99         struct softpart part1, part2;
 100         struct  prison *pt_prison;
 101 };
 102
 103 #define PF_STOPPED      0x10            /* user told stopped */
 104
 105 static void
 106 nmdm_crossover(struct nm_softc *pti,
 107                 struct softpart *ourpart,
 108                 struct softpart *otherpart);
 109
 110 #define GETPARTS(tp, ourpart, otherpart) \
 111 do {    \
 112         struct nm_softc *pti = tp->t_dev->si_drv1; \
 113         if (tp == &pti->part1.nm_tty) { \
 114                 ourpart = &pti->part1; \
 115                 otherpart = &pti->part2; \
 116         } else { \
 117                 ourpart = &pti->part2; \
 118                 otherpart = &pti->part1; \
 119         }  \
 120 } while (0)
 121
 122 /*
 123  * This function creates and initializes a pair of ttys.
 124  *
 125  * NOTE: Must be called with tty_token held
 126  */
 127 static void
 128 nmdminit(int n)
 129 {
 130         cdev_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         ASSERT_LWKT_TOKEN_HELD(&tty_token);
 141
 142         pt = kmalloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
 143         pt->part1.dev = dev1 = make_dev(&nmdm_ops, n << 1,
 144                                         0, 0, 0666, "nmdm%dA", n);
 145         pt->part2.dev = dev2 = make_dev(&nmdm_ops, (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(struct dev_open_args *ap)
 164 {
 165         cdev_t dev = ap->a_head.a_dev;
 166         struct tty *tp, *tp2;
 167         int error;
 168         int minr;
 169 #if 0
 170         cdev_t nextdev;
 171 #endif
 172         struct nm_softc *pti;
 173         int is_b;
 174         int     pair;
 175         struct  softpart *ourpart, *otherpart;
 176
 177         minr = lminor(dev);
 178         pair = minr >> 1;
 179         is_b = minr & 1;
 180
 181 #if 0
 182         /*
 183          * XXX: Gross hack for DEVFS:
 184          * If we openned this device, ensure we have the
 185          * next one too, so people can open it.
 186          */
 187         if (pair < 127) {
 188                 nextdev = makedev(major(dev), (pair+pair) + 1);
 189                 if (!nextdev->si_drv1) {
 190                         nmdminit(pair + 1);
 191                 }
 192         }
 193 #endif
 194         if (!dev->si_drv1)
 195                 nmdminit(pair);
 196
 197         if (!dev->si_drv1)
 198                 return(ENXIO);
 199
 200         lwkt_gettoken(&tty_token);
 201         pti = dev->si_drv1;
 202         if (is_b)
 203                 tp = &pti->part2.nm_tty;
 204         else
 205                 tp = &pti->part1.nm_tty;
 206         GETPARTS(tp, ourpart, otherpart);
 207         tp2 = &otherpart->nm_tty;
 208         ourpart->modemsignals |= TIOCM_LE;
 209
 210         if ((tp->t_state & TS_ISOPEN) == 0) {
 211                 ttychars(tp);           /* Set up default chars */
 212                 tp->t_iflag = TTYDEF_IFLAG;
 213                 tp->t_oflag = TTYDEF_OFLAG;
 214                 tp->t_lflag = TTYDEF_LFLAG;
 215                 tp->t_cflag = TTYDEF_CFLAG;
 216                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 217         } else if (tp->t_state & TS_XCLUDE && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
 218                 lwkt_reltoken(&tty_token);
 219                 return (EBUSY);
 220         } else if (pti->pt_prison != ap->a_cred->cr_prison) {
 221                 lwkt_reltoken(&tty_token);
 222                 return (EBUSY);
 223         }
 224
 225         /*
 226          * If the other side is open we have carrier
 227          */
 228         if (tp2->t_state & TS_ISOPEN) {
 229                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 230         }
 231
 232         /*
 233          * And the other side gets carrier as we are now open.
 234          */
 235         (void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
 236
 237         /* External processing makes no sense here */
 238         tp->t_lflag &= ~EXTPROC;
 239
 240         /*
 241          * Wait here if we don't have carrier.
 242          */
 243 #if 0
 244         while ((tp->t_state & TS_CARR_ON) == 0) {
 245                 if (flag & FNONBLOCK)
 246                         break;
 247                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
 248                 if (error) {
 249                         lwkt_reltoken(&tty_token);
 250                         return (error);
 251                 }
 252         }
 253 #endif
 254
 255         /*
 256          * Give the line disciplin a chance to set this end up.
 257          */
 258         error = (*linesw[tp->t_line].l_open)(dev, tp);
 259
 260         /*
 261          * Wake up the other side.
 262          * Theoretically not needed.
 263          */
 264         ourpart->modemsignals |= TIOCM_DTR;
 265         nmdm_crossover(pti, ourpart, otherpart);
 266         if (error == 0)
 267                 wakeup_other(tp, FREAD|FWRITE); /* XXX */
 268         lwkt_reltoken(&tty_token);
 269         return (error);
 270 }
 271
 272 static int
 273 nmdmclose(struct dev_close_args *ap)
 274 {
 275         cdev_t dev = ap->a_head.a_dev;
 276         struct tty *tp, *tp2;
 277         int err;
 278         struct softpart *ourpart, *otherpart;
 279
 280         lwkt_gettoken(&tty_token);
 281         /*
 282          * let the other end know that the game is up
 283          */
 284         tp = dev->si_tty;
 285         GETPARTS(tp, ourpart, otherpart);
 286         tp2 = &otherpart->nm_tty;
 287         (void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
 288
 289         /*
 290          * XXX MDMBUF makes no sense for nmdms but would inhibit the above
 291          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 292          * l_modem()s that ignore carrier drop make no sense for nmdms but
 293          * may be in use because other parts of the line discipline make
 294          * sense for nmdms.  Recover by doing everything that a normal
 295          * ttymodem() would have done except for sending a SIGHUP.
 296          */
 297         if (tp2->t_state & TS_ISOPEN) {
 298                 tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 299                 tp2->t_state |= TS_ZOMBIE;
 300                 ttyflush(tp2, FREAD | FWRITE);
 301         }
 302
 303         err = (*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
 304         ourpart->modemsignals &= ~TIOCM_DTR;
 305         nmdm_crossover(dev->si_drv1, ourpart, otherpart);
 306         nmdmstop(tp, FREAD|FWRITE);
 307         (void) ttyclose(tp);
 308         lwkt_reltoken(&tty_token);
 309         return (err);
 310 }
 311
 312 static int
 313 nmdmread(struct dev_read_args *ap)
 314 {
 315         cdev_t dev = ap->a_head.a_dev;
 316         int error = 0;
 317         struct tty *tp;
 318 #if 0
 319         struct tty *tp2;
 320         struct softpart *ourpart, *otherpart;
 321 #endif
 322
 323         lwkt_gettoken(&tty_token);
 324         tp = dev->si_tty;
 325 #if 0
 326         GETPARTS(tp, ourpart, otherpart);
 327         tp2 = &otherpart->nm_tty;
 328
 329         if (tp2->t_state & TS_ISOPEN) {
 330                 error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
 331                 wakeup_other(tp, FWRITE);
 332         } else {
 333                 if (flag & IO_NDELAY) {
 334                         lwkt_reltoken(&tty_token);
 335                         return (EWOULDBLOCK);
 336                 }
 337                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 338                 }
 339         }
 340 #else
 341         if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
 342                 wakeup_other(tp, FWRITE);
 343 #endif
 344         lwkt_reltoken(&tty_token);
 345         return (error);
 346 }
 347
 348 /*
 349  * Write to pseudo-tty.
 350  * Wakeups of controlling tty will happen
 351  * indirectly, when tty driver calls nmdmstart.
 352  */
 353 static  int
 354 nmdmwrite(struct dev_write_args *ap)
 355 {
 356         cdev_t dev = ap->a_head.a_dev;
 357         struct uio *uio = ap->a_uio;
 358         u_char *cp = NULL;
 359         size_t cc = 0;
 360         u_char locbuf[BUFSIZ];
 361         int cnt = 0;
 362         int error = 0;
 363         struct tty *tp1, *tp;
 364         struct softpart *ourpart, *otherpart;
 365
 366         lwkt_gettoken(&tty_token);
 367         tp1 = dev->si_tty;
 368         /*
 369          * Get the other tty struct.
 370          * basically we are writing into the INPUT side of the other device.
 371          */
 372         GETPARTS(tp1, ourpart, otherpart);
 373         tp = &otherpart->nm_tty;
 374
 375 again:
 376         if ((tp->t_state & TS_ISOPEN) == 0) {
 377                 lwkt_reltoken(&tty_token);
 378                 return (EIO);
 379         }
 380         while (uio->uio_resid > 0 || cc > 0) {
 381                 /*
 382                  * Fill up the buffer if it's empty
 383                  */
 384                 if (cc == 0) {
 385                         cc = szmin(uio->uio_resid, BUFSIZ);
 386                         cp = locbuf;
 387                         error = uiomove((caddr_t)cp, cc, uio);
 388                         if (error) {
 389                                 lwkt_reltoken(&tty_token);
 390                                 return (error);
 391                         }
 392                         /* check again for safety */
 393                         if ((tp->t_state & TS_ISOPEN) == 0) {
 394                                 /* adjust for data copied in but not written */
 395                                 uio->uio_resid += cc;
 396                                 lwkt_reltoken(&tty_token);
 397                                 return (EIO);
 398                         }
 399                 }
 400                 while (cc > 0) {
 401                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 402                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 403                                 /*
 404                                  * Come here to wait for space in outq,
 405                                  * or space in rawq, or an empty canq.
 406                                  */
 407                                 wakeup(TSA_HUP_OR_INPUT(tp));
 408                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 409                                         /*
 410                                          * Data piled up because not connected.
 411                                          * Adjust for data copied in but
 412                                          * not written.
 413                                          */
 414                                         uio->uio_resid += cc;
 415                                         lwkt_reltoken(&tty_token);
 416                                         return (EIO);
 417                                 }
 418                                 if (ap->a_ioflag & IO_NDELAY) {
 419                                         /*
 420                                          * Don't wait if asked not to.
 421                                          * Adjust for data copied in but
 422                                          * not written.
 423                                          */
 424                                         uio->uio_resid += cc;
 425                                         if (cnt == 0) {
 426                                                 lwkt_reltoken(&tty_token);
 427                                                 return (EWOULDBLOCK);
 428                                         }
 429                                         lwkt_reltoken(&tty_token);
 430                                         return (0);
 431                                 }
 432                                 error = tsleep(TSA_PTC_WRITE(tp),
 433                                                 PCATCH, "nmdout", 0);
 434                                 if (error) {
 435                                         /*
 436                                          * Tsleep returned (signal?).
 437                                          * Go find out what the user wants.
 438                                          * adjust for data copied in but
 439                                          * not written
 440                                          */
 441                                         uio->uio_resid += cc;
 442                                         lwkt_reltoken(&tty_token);
 443                                         return (error);
 444                                 }
 445                                 goto again;
 446                         }
 447                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 448                         cnt++;
 449                         cc--;
 450                 }
 451                 cc = 0;
 452         }
 453         lwkt_reltoken(&tty_token);
 454         return (0);
 455 }
 456
 457 /*
 458  * Start output on pseudo-tty.
 459  * Wake up process selecting or sleeping for input from controlling tty.
 460  */
 461 static void
 462 nmdmstart(struct tty *tp)
 463 {
 464         struct nm_softc *pti = tp->t_dev->si_drv1;
 465
 466         lwkt_gettoken(&tty_token);
 467         if (tp->t_state & TS_TTSTOP) {
 468                 lwkt_reltoken(&tty_token);
 469                 return;
 470         }
 471         pti->pt_flags &= ~PF_STOPPED;
 472         wakeup_other(tp, FREAD);
 473         lwkt_reltoken(&tty_token);
 474 }
 475
 476 /* Wakes up the OTHER tty;*/
 477 static void
 478 wakeup_other(struct tty *tp, int flag)
 479 {
 480         struct softpart *ourpart, *otherpart;
 481
 482         lwkt_gettoken(&tty_token);
 483         GETPARTS(tp, ourpart, otherpart);
 484         if (flag & FREAD) {
 485                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 486                 KNOTE(&otherpart->nm_tty.t_rkq.ki_note, 0);
 487         }
 488         if (flag & FWRITE) {
 489                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 490                 KNOTE(&otherpart->nm_tty.t_wkq.ki_note, 0);
 491         }
 492         lwkt_reltoken(&tty_token);
 493 }
 494
 495 static  void
 496 nmdmstop(struct tty *tp, int flush)
 497 {
 498         struct nm_softc *pti = tp->t_dev->si_drv1;
 499         int flag;
 500
 501         lwkt_gettoken(&tty_token);
 502         /* note: FLUSHREAD and FLUSHWRITE already ok */
 503         if (flush == 0) {
 504                 flush = TIOCPKT_STOP;
 505                 pti->pt_flags |= PF_STOPPED;
 506         } else
 507                 pti->pt_flags &= ~PF_STOPPED;
 508         /* change of perspective */
 509         flag = 0;
 510         if (flush & FREAD)
 511                 flag |= FWRITE;
 512         if (flush & FWRITE)
 513                 flag |= FREAD;
 514         wakeup_other(tp, flag);
 515         lwkt_reltoken(&tty_token);
 516 }
 517
 518 /*ARGSUSED*/
 519 static  int
 520 nmdmioctl(struct dev_ioctl_args *ap)
 521 {
 522         cdev_t dev = ap->a_head.a_dev;
 523         struct tty *tp = dev->si_tty;
 524         struct nm_softc *pti = dev->si_drv1;
 525         int error;
 526         struct softpart *ourpart, *otherpart;
 527
 528         crit_enter();
 529         lwkt_gettoken(&tty_token);
 530         GETPARTS(tp, ourpart, otherpart);
 531
 532         error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
 533                                               ap->a_fflag, ap->a_cred);
 534         if (error == ENOIOCTL)
 535                  error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
 536         if (error == ENOIOCTL) {
 537                 switch (ap->a_cmd) {
 538                 case TIOCSBRK:
 539                         otherpart->gotbreak = 1;
 540                         break;
 541                 case TIOCCBRK:
 542                         break;
 543                 case TIOCSDTR:
 544                         ourpart->modemsignals |= TIOCM_DTR;
 545                         break;
 546                 case TIOCCDTR:
 547                         ourpart->modemsignals &= TIOCM_DTR;
 548                         break;
 549                 case TIOCMSET:
 550                         ourpart->modemsignals = *(int *)ap->a_data;
 551                         otherpart->modemsignals = *(int *)ap->a_data;
 552                         break;
 553                 case TIOCMBIS:
 554                         ourpart->modemsignals |= *(int *)ap->a_data;
 555                         break;
 556                 case TIOCMBIC:
 557                         ourpart->modemsignals &= ~(*(int *)ap->a_data);
 558                         otherpart->modemsignals &= ~(*(int *)ap->a_data);
 559                         break;
 560                 case TIOCMGET:
 561                         *(int *)ap->a_data = ourpart->modemsignals;
 562                         break;
 563                 case TIOCMSDTRWAIT:
 564                         break;
 565                 case TIOCMGDTRWAIT:
 566                         *(int *)ap->a_data = 0;
 567                         break;
 568                 case TIOCTIMESTAMP:
 569                 case TIOCDCDTIMESTAMP:
 570                 default:
 571                         lwkt_reltoken(&tty_token);
 572                         crit_exit();
 573                         error = ENOTTY;
 574                         return (error);
 575                 }
 576                 error = 0;
 577                 nmdm_crossover(pti, ourpart, otherpart);
 578         }
 579         lwkt_reltoken(&tty_token);
 580         crit_exit();
 581         return (error);
 582 }
 583
 584 static void
 585 nmdm_crossover(struct nm_softc *pti,
 586                 struct softpart *ourpart,
 587                 struct softpart *otherpart)
 588 {
 589         lwkt_gettoken(&tty_token);
 590         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 591         if (ourpart->modemsignals & TIOCM_RTS)
 592                 otherpart->modemsignals |= TIOCM_CTS;
 593         if (ourpart->modemsignals & TIOCM_DTR)
 594                 otherpart->modemsignals |= TIOCM_CAR;
 595         lwkt_reltoken(&tty_token);
 596 }
 597
 598
 599
 600 static void nmdm_drvinit (void *unused);
 601
 602 static void
 603 nmdm_drvinit(void *unused)
 604 {
 605         /* XXX: Gross hack for DEVFS */
 606         lwkt_gettoken(&tty_token);
 607         nmdminit(0);
 608         lwkt_reltoken(&tty_token);
 609 }
 610
 611 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)