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) || defined(COMPAT_SUNOS)
  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, *tp2;
 318         struct softpart *ourpart, *otherpart;
 319
 320         lwkt_gettoken(&tty_token);
 321         tp = dev->si_tty;
 322         GETPARTS(tp, ourpart, otherpart);
 323         tp2 = &otherpart->nm_tty;
 324
 325 #if 0
 326         if (tp2->t_state & TS_ISOPEN) {
 327                 error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
 328                 wakeup_other(tp, FWRITE);
 329         } else {
 330                 if (flag & IO_NDELAY) {
 331                         lwkt_reltoken(&tty_token);
 332                         return (EWOULDBLOCK);
 333                 }
 334                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 335                 }
 336         }
 337 #else
 338         if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
 339                 wakeup_other(tp, FWRITE);
 340 #endif
 341         lwkt_reltoken(&tty_token);
 342         return (error);
 343 }
 344
 345 /*
 346  * Write to pseudo-tty.
 347  * Wakeups of controlling tty will happen
 348  * indirectly, when tty driver calls nmdmstart.
 349  */
 350 static  int
 351 nmdmwrite(struct dev_write_args *ap)
 352 {
 353         cdev_t dev = ap->a_head.a_dev;
 354         struct uio *uio = ap->a_uio;
 355         u_char *cp = NULL;
 356         size_t cc = 0;
 357         u_char locbuf[BUFSIZ];
 358         int cnt = 0;
 359         int error = 0;
 360         struct tty *tp1, *tp;
 361         struct softpart *ourpart, *otherpart;
 362
 363         lwkt_gettoken(&tty_token);
 364         tp1 = dev->si_tty;
 365         /*
 366          * Get the other tty struct.
 367          * basically we are writing into the INPUT side of the other device.
 368          */
 369         GETPARTS(tp1, ourpart, otherpart);
 370         tp = &otherpart->nm_tty;
 371
 372 again:
 373         if ((tp->t_state & TS_ISOPEN) == 0) {
 374                 lwkt_reltoken(&tty_token);
 375                 return (EIO);
 376         }
 377         while (uio->uio_resid > 0 || cc > 0) {
 378                 /*
 379                  * Fill up the buffer if it's empty
 380                  */
 381                 if (cc == 0) {
 382                         cc = szmin(uio->uio_resid, BUFSIZ);
 383                         cp = locbuf;
 384                         error = uiomove((caddr_t)cp, cc, uio);
 385                         if (error) {
 386                                 lwkt_reltoken(&tty_token);
 387                                 return (error);
 388                         }
 389                         /* check again for safety */
 390                         if ((tp->t_state & TS_ISOPEN) == 0) {
 391                                 /* adjust for data copied in but not written */
 392                                 uio->uio_resid += cc;
 393                                 lwkt_reltoken(&tty_token);
 394                                 return (EIO);
 395                         }
 396                 }
 397                 while (cc > 0) {
 398                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 399                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 400                                 /*
 401                                  * Come here to wait for space in outq,
 402                                  * or space in rawq, or an empty canq.
 403                                  */
 404                                 wakeup(TSA_HUP_OR_INPUT(tp));
 405                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 406                                         /*
 407                                          * Data piled up because not connected.
 408                                          * Adjust for data copied in but
 409                                          * not written.
 410                                          */
 411                                         uio->uio_resid += cc;
 412                                         lwkt_reltoken(&tty_token);
 413                                         return (EIO);
 414                                 }
 415                                 if (ap->a_ioflag & IO_NDELAY) {
 416                                         /*
 417                                          * Don't wait if asked not to.
 418                                          * Adjust for data copied in but
 419                                          * not written.
 420                                          */
 421                                         uio->uio_resid += cc;
 422                                         if (cnt == 0) {
 423                                                 lwkt_reltoken(&tty_token);
 424                                                 return (EWOULDBLOCK);
 425                                         }
 426                                         lwkt_reltoken(&tty_token);
 427                                         return (0);
 428                                 }
 429                                 error = tsleep(TSA_PTC_WRITE(tp),
 430                                                 PCATCH, "nmdout", 0);
 431                                 if (error) {
 432                                         /*
 433                                          * Tsleep returned (signal?).
 434                                          * Go find out what the user wants.
 435                                          * adjust for data copied in but
 436                                          * not written
 437                                          */
 438                                         uio->uio_resid += cc;
 439                                         lwkt_reltoken(&tty_token);
 440                                         return (error);
 441                                 }
 442                                 goto again;
 443                         }
 444                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 445                         cnt++;
 446                         cc--;
 447                 }
 448                 cc = 0;
 449         }
 450         lwkt_reltoken(&tty_token);
 451         return (0);
 452 }
 453
 454 /*
 455  * Start output on pseudo-tty.
 456  * Wake up process selecting or sleeping for input from controlling tty.
 457  */
 458 static void
 459 nmdmstart(struct tty *tp)
 460 {
 461         struct nm_softc *pti = tp->t_dev->si_drv1;
 462
 463         lwkt_gettoken(&tty_token);
 464         if (tp->t_state & TS_TTSTOP) {
 465                 lwkt_reltoken(&tty_token);
 466                 return;
 467         }
 468         pti->pt_flags &= ~PF_STOPPED;
 469         wakeup_other(tp, FREAD);
 470         lwkt_reltoken(&tty_token);
 471 }
 472
 473 /* Wakes up the OTHER tty;*/
 474 static void
 475 wakeup_other(struct tty *tp, int flag)
 476 {
 477         struct softpart *ourpart, *otherpart;
 478
 479         lwkt_gettoken(&tty_token);
 480         GETPARTS(tp, ourpart, otherpart);
 481         if (flag & FREAD) {
 482                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 483                 KNOTE(&otherpart->nm_tty.t_rkq.ki_note, 0);
 484         }
 485         if (flag & FWRITE) {
 486                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 487                 KNOTE(&otherpart->nm_tty.t_wkq.ki_note, 0);
 488         }
 489         lwkt_reltoken(&tty_token);
 490 }
 491
 492 static  void
 493 nmdmstop(struct tty *tp, int flush)
 494 {
 495         struct nm_softc *pti = tp->t_dev->si_drv1;
 496         int flag;
 497
 498         lwkt_gettoken(&tty_token);
 499         /* note: FLUSHREAD and FLUSHWRITE already ok */
 500         if (flush == 0) {
 501                 flush = TIOCPKT_STOP;
 502                 pti->pt_flags |= PF_STOPPED;
 503         } else
 504                 pti->pt_flags &= ~PF_STOPPED;
 505         /* change of perspective */
 506         flag = 0;
 507         if (flush & FREAD)
 508                 flag |= FWRITE;
 509         if (flush & FWRITE)
 510                 flag |= FREAD;
 511         wakeup_other(tp, flag);
 512         lwkt_reltoken(&tty_token);
 513 }
 514
 515 /*ARGSUSED*/
 516 static  int
 517 nmdmioctl(struct dev_ioctl_args *ap)
 518 {
 519         cdev_t dev = ap->a_head.a_dev;
 520         struct tty *tp = dev->si_tty;
 521         struct nm_softc *pti = dev->si_drv1;
 522         int error;
 523         struct tty *tp2;
 524         struct softpart *ourpart, *otherpart;
 525
 526         crit_enter();
 527         lwkt_gettoken(&tty_token);
 528         GETPARTS(tp, ourpart, otherpart);
 529         tp2 = &otherpart->nm_tty;
 530
 531         error = (*linesw[tp->t_line].l_ioctl)(tp, ap->a_cmd, ap->a_data,
 532                                               ap->a_fflag, ap->a_cred);
 533         if (error == ENOIOCTL)
 534                  error = ttioctl(tp, ap->a_cmd, ap->a_data, ap->a_fflag);
 535         if (error == ENOIOCTL) {
 536                 switch (ap->a_cmd) {
 537                 case TIOCSBRK:
 538                         otherpart->gotbreak = 1;
 539                         break;
 540                 case TIOCCBRK:
 541                         break;
 542                 case TIOCSDTR:
 543                         ourpart->modemsignals |= TIOCM_DTR;
 544                         break;
 545                 case TIOCCDTR:
 546                         ourpart->modemsignals &= TIOCM_DTR;
 547                         break;
 548                 case TIOCMSET:
 549                         ourpart->modemsignals = *(int *)ap->a_data;
 550                         otherpart->modemsignals = *(int *)ap->a_data;
 551                         break;
 552                 case TIOCMBIS:
 553                         ourpart->modemsignals |= *(int *)ap->a_data;
 554                         break;
 555                 case TIOCMBIC:
 556                         ourpart->modemsignals &= ~(*(int *)ap->a_data);
 557                         otherpart->modemsignals &= ~(*(int *)ap->a_data);
 558                         break;
 559                 case TIOCMGET:
 560                         *(int *)ap->a_data = ourpart->modemsignals;
 561                         break;
 562                 case TIOCMSDTRWAIT:
 563                         break;
 564                 case TIOCMGDTRWAIT:
 565                         *(int *)ap->a_data = 0;
 566                         break;
 567                 case TIOCTIMESTAMP:
 568                 case TIOCDCDTIMESTAMP:
 569                 default:
 570                         lwkt_reltoken(&tty_token);
 571                         crit_exit();
 572                         error = ENOTTY;
 573                         return (error);
 574                 }
 575                 error = 0;
 576                 nmdm_crossover(pti, ourpart, otherpart);
 577         }
 578         lwkt_reltoken(&tty_token);
 579         crit_exit();
 580         return (error);
 581 }
 582
 583 static void
 584 nmdm_crossover(struct nm_softc *pti,
 585                 struct softpart *ourpart,
 586                 struct softpart *otherpart)
 587 {
 588         lwkt_gettoken(&tty_token);
 589         otherpart->modemsignals &= ~(TIOCM_CTS|TIOCM_CAR);
 590         if (ourpart->modemsignals & TIOCM_RTS)
 591                 otherpart->modemsignals |= TIOCM_CTS;
 592         if (ourpart->modemsignals & TIOCM_DTR)
 593                 otherpart->modemsignals |= TIOCM_CAR;
 594         lwkt_reltoken(&tty_token);
 595 }
 596
 597
 598
 599 static void nmdm_drvinit (void *unused);
 600
 601 static void
 602 nmdm_drvinit(void *unused)
 603 {
 604         /* XXX: Gross hack for DEVFS */
 605         lwkt_gettoken(&tty_token);
 606         nmdminit(0);
 607         lwkt_reltoken(&tty_token);
 608 }
 609
 610 SYSINIT(nmdmdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,nmdm_drvinit,NULL)