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  * $DragonFly: src/sys/dev/misc/nmdm/nmdm.c,v 1.16 2008/01/05 14:02:37 swildner Exp $
  37  */
  38
  39 /*
  40  * MPSAFE NOTE: This file acquires the tty_token mainly for linesw access and
  41  *              tp (struct tty) access.
  42  */
  43
  44 /*
  45  * Pseudo-nulmodem Driver
  46  */
  47 #include "opt_compat.h"
  48 #include <sys/param.h>
  49 #include <sys/systm.h>
  50 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
  51 #include <sys/ioctl_compat.h>
  52 #endif
  53 #include <sys/proc.h>
  54 #include <sys/priv.h>
  55 #include <sys/thread2.h>
  56 #include <sys/tty.h>
  57 #include <sys/conf.h>
  58 #include <sys/fcntl.h>
  59 #include <sys/kernel.h>
  60 #include <sys/vnode.h>
  61 #include <sys/signalvar.h>
  62 #include <sys/malloc.h>
  63
  64 MALLOC_DEFINE(M_NLMDM, "nullmodem", "nullmodem data structures");
  65
  66 static void nmdmstart (struct tty *tp);
  67 static void nmdmstop (struct tty *tp, int rw);
  68 static void wakeup_other (struct tty *tp, int flag);
  69 static void nmdminit (int n);
  70
  71 static  d_open_t        nmdmopen;
  72 static  d_close_t       nmdmclose;
  73 static  d_read_t        nmdmread;
  74 static  d_write_t       nmdmwrite;
  75 static  d_ioctl_t       nmdmioctl;
  76
  77 #define CDEV_MAJOR      18
  78 static struct dev_ops nmdm_ops = {
  79         { "pts", CDEV_MAJOR, D_TTY },
  80         .d_open =       nmdmopen,
  81         .d_close =      nmdmclose,
  82         .d_read =       nmdmread,
  83         .d_write =      nmdmwrite,
  84         .d_ioctl =      nmdmioctl,
  85         .d_kqfilter =   ttykqfilter,
  86         .d_revoke =     ttyrevoke
  87 };
  88
  89 #define BUFSIZ 100              /* Chunk size iomoved to/from user */
  90
  91 struct softpart {
  92         struct tty nm_tty;
  93         cdev_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  * NOTE: Must be called with tty_token held
 127  */
 128 static void
 129 nmdminit(int n)
 130 {
 131         cdev_t dev1, dev2;
 132         struct nm_softc *pt;
 133
 134         /*
 135          * Simplified unit number, use low 8 bits of minor number
 136          * (remember, the minor number mask is 0xffff00ff).
 137          */
 138         if (n & ~0x7f)
 139                 return;
 140
 141         ASSERT_LWKT_TOKEN_HELD(&tty_token);
 142
 143         pt = kmalloc(sizeof(*pt), M_NLMDM, M_WAITOK | M_ZERO);
 144         pt->part1.dev = dev1 = make_dev(&nmdm_ops, n << 1,
 145                                         0, 0, 0666, "nmdm%dA", n);
 146         pt->part2.dev = dev2 = make_dev(&nmdm_ops, (n << 1) + 1,
 147                                         0, 0, 0666, "nmdm%dB", n);
 148
 149         dev1->si_drv1 = dev2->si_drv1 = pt;
 150         dev1->si_tty = &pt->part1.nm_tty;
 151         dev2->si_tty = &pt->part2.nm_tty;
 152         ttyregister(&pt->part1.nm_tty);
 153         ttyregister(&pt->part2.nm_tty);
 154         pt->part1.nm_tty.t_oproc = nmdmstart;
 155         pt->part2.nm_tty.t_oproc = nmdmstart;
 156         pt->part1.nm_tty.t_stop = nmdmstop;
 157         pt->part2.nm_tty.t_dev = dev1;
 158         pt->part1.nm_tty.t_dev = dev2;
 159         pt->part2.nm_tty.t_stop = nmdmstop;
 160 }
 161
 162 /*ARGSUSED*/
 163 static  int
 164 nmdmopen(struct dev_open_args *ap)
 165 {
 166         cdev_t dev = ap->a_head.a_dev;
 167         struct tty *tp, *tp2;
 168         int error;
 169         int minr;
 170 #if 0
 171         cdev_t nextdev;
 172 #endif
 173         struct nm_softc *pti;
 174         int is_b;
 175         int     pair;
 176         struct  softpart *ourpart, *otherpart;
 177
 178         minr = lminor(dev);
 179         pair = minr >> 1;
 180         is_b = minr & 1;
 181
 182 #if 0
 183         /*
 184          * XXX: Gross hack for DEVFS:
 185          * If we openned this device, ensure we have the
 186          * next one too, so people can open it.
 187          */
 188         if (pair < 127) {
 189                 nextdev = makedev(major(dev), (pair+pair) + 1);
 190                 if (!nextdev->si_drv1) {
 191                         nmdminit(pair + 1);
 192                 }
 193         }
 194 #endif
 195         if (!dev->si_drv1)
 196                 nmdminit(pair);
 197
 198         if (!dev->si_drv1)
 199                 return(ENXIO);
 200
 201         lwkt_gettoken(&tty_token);
 202         pti = dev->si_drv1;
 203         if (is_b)
 204                 tp = &pti->part2.nm_tty;
 205         else
 206                 tp = &pti->part1.nm_tty;
 207         GETPARTS(tp, ourpart, otherpart);
 208         tp2 = &otherpart->nm_tty;
 209         ourpart->modemsignals |= TIOCM_LE;
 210
 211         if ((tp->t_state & TS_ISOPEN) == 0) {
 212                 ttychars(tp);           /* Set up default chars */
 213                 tp->t_iflag = TTYDEF_IFLAG;
 214                 tp->t_oflag = TTYDEF_OFLAG;
 215                 tp->t_lflag = TTYDEF_LFLAG;
 216                 tp->t_cflag = TTYDEF_CFLAG;
 217                 tp->t_ispeed = tp->t_ospeed = TTYDEF_SPEED;
 218         } else if (tp->t_state & TS_XCLUDE && priv_check_cred(ap->a_cred, PRIV_ROOT, 0)) {
 219                 lwkt_reltoken(&tty_token);
 220                 return (EBUSY);
 221         } else if (pti->pt_prison != ap->a_cred->cr_prison) {
 222                 lwkt_reltoken(&tty_token);
 223                 return (EBUSY);
 224         }
 225
 226         /*
 227          * If the other side is open we have carrier
 228          */
 229         if (tp2->t_state & TS_ISOPEN) {
 230                 (void)(*linesw[tp->t_line].l_modem)(tp, 1);
 231         }
 232
 233         /*
 234          * And the other side gets carrier as we are now open.
 235          */
 236         (void)(*linesw[tp2->t_line].l_modem)(tp2, 1);
 237
 238         /* External processing makes no sense here */
 239         tp->t_lflag &= ~EXTPROC;
 240
 241         /*
 242          * Wait here if we don't have carrier.
 243          */
 244 #if 0
 245         while ((tp->t_state & TS_CARR_ON) == 0) {
 246                 if (flag & FNONBLOCK)
 247                         break;
 248                 error = ttysleep(tp, TSA_CARR_ON(tp), PCATCH, "nmdopn", 0);
 249                 if (error) {
 250                         lwkt_reltoken(&tty_token);
 251                         return (error);
 252                 }
 253         }
 254 #endif
 255
 256         /*
 257          * Give the line disciplin a chance to set this end up.
 258          */
 259         error = (*linesw[tp->t_line].l_open)(dev, tp);
 260
 261         /*
 262          * Wake up the other side.
 263          * Theoretically not needed.
 264          */
 265         ourpart->modemsignals |= TIOCM_DTR;
 266         nmdm_crossover(pti, ourpart, otherpart);
 267         if (error == 0)
 268                 wakeup_other(tp, FREAD|FWRITE); /* XXX */
 269         lwkt_reltoken(&tty_token);
 270         return (error);
 271 }
 272
 273 static int
 274 nmdmclose(struct dev_close_args *ap)
 275 {
 276         cdev_t dev = ap->a_head.a_dev;
 277         struct tty *tp, *tp2;
 278         int err;
 279         struct softpart *ourpart, *otherpart;
 280
 281         lwkt_gettoken(&tty_token);
 282         /*
 283          * let the other end know that the game is up
 284          */
 285         tp = dev->si_tty;
 286         GETPARTS(tp, ourpart, otherpart);
 287         tp2 = &otherpart->nm_tty;
 288         (void)(*linesw[tp2->t_line].l_modem)(tp2, 0);
 289
 290         /*
 291          * XXX MDMBUF makes no sense for nmdms but would inhibit the above
 292          * l_modem().  CLOCAL makes sense but isn't supported.   Special
 293          * l_modem()s that ignore carrier drop make no sense for nmdms but
 294          * may be in use because other parts of the line discipline make
 295          * sense for nmdms.  Recover by doing everything that a normal
 296          * ttymodem() would have done except for sending a SIGHUP.
 297          */
 298         if (tp2->t_state & TS_ISOPEN) {
 299                 tp2->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
 300                 tp2->t_state |= TS_ZOMBIE;
 301                 ttyflush(tp2, FREAD | FWRITE);
 302         }
 303
 304         err = (*linesw[tp->t_line].l_close)(tp, ap->a_fflag);
 305         ourpart->modemsignals &= ~TIOCM_DTR;
 306         nmdm_crossover(dev->si_drv1, ourpart, otherpart);
 307         nmdmstop(tp, FREAD|FWRITE);
 308         (void) ttyclose(tp);
 309         lwkt_reltoken(&tty_token);
 310         return (err);
 311 }
 312
 313 static int
 314 nmdmread(struct dev_read_args *ap)
 315 {
 316         cdev_t dev = ap->a_head.a_dev;
 317         int error = 0;
 318         struct tty *tp, *tp2;
 319         struct softpart *ourpart, *otherpart;
 320
 321         lwkt_gettoken(&tty_token);
 322         tp = dev->si_tty;
 323         GETPARTS(tp, ourpart, otherpart);
 324         tp2 = &otherpart->nm_tty;
 325
 326 #if 0
 327         if (tp2->t_state & TS_ISOPEN) {
 328                 error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, flag);
 329                 wakeup_other(tp, FWRITE);
 330         } else {
 331                 if (flag & IO_NDELAY) {
 332                         lwkt_reltoken(&tty_token);
 333                         return (EWOULDBLOCK);
 334                 }
 335                 error = tsleep(TSA_PTC_READ(tp), PCATCH, "nmdout", 0);
 336                 }
 337         }
 338 #else
 339         if ((error = (*linesw[tp->t_line].l_read)(tp, ap->a_uio, ap->a_ioflag)) == 0)
 340                 wakeup_other(tp, FWRITE);
 341 #endif
 342         lwkt_reltoken(&tty_token);
 343         return (error);
 344 }
 345
 346 /*
 347  * Write to pseudo-tty.
 348  * Wakeups of controlling tty will happen
 349  * indirectly, when tty driver calls nmdmstart.
 350  */
 351 static  int
 352 nmdmwrite(struct dev_write_args *ap)
 353 {
 354         cdev_t dev = ap->a_head.a_dev;
 355         struct uio *uio = ap->a_uio;
 356         u_char *cp = 0;
 357         size_t cc = 0;
 358         u_char locbuf[BUFSIZ];
 359         int cnt = 0;
 360         int error = 0;
 361         struct tty *tp1, *tp;
 362         struct softpart *ourpart, *otherpart;
 363
 364         lwkt_gettoken(&tty_token);
 365         tp1 = dev->si_tty;
 366         /*
 367          * Get the other tty struct.
 368          * basically we are writing into the INPUT side of the other device.
 369          */
 370         GETPARTS(tp1, ourpart, otherpart);
 371         tp = &otherpart->nm_tty;
 372
 373 again:
 374         if ((tp->t_state & TS_ISOPEN) == 0) {
 375                 lwkt_reltoken(&tty_token);
 376                 return (EIO);
 377         }
 378         while (uio->uio_resid > 0 || cc > 0) {
 379                 /*
 380                  * Fill up the buffer if it's empty
 381                  */
 382                 if (cc == 0) {
 383                         cc = szmin(uio->uio_resid, BUFSIZ);
 384                         cp = locbuf;
 385                         error = uiomove((caddr_t)cp, cc, uio);
 386                         if (error) {
 387                                 lwkt_reltoken(&tty_token);
 388                                 return (error);
 389                         }
 390                         /* check again for safety */
 391                         if ((tp->t_state & TS_ISOPEN) == 0) {
 392                                 /* adjust for data copied in but not written */
 393                                 uio->uio_resid += cc;
 394                                 lwkt_reltoken(&tty_token);
 395                                 return (EIO);
 396                         }
 397                 }
 398                 while (cc > 0) {
 399                         if (((tp->t_rawq.c_cc + tp->t_canq.c_cc) >= (TTYHOG-2))
 400                         && ((tp->t_canq.c_cc > 0) || !(tp->t_iflag&ICANON))) {
 401                                 /*
 402                                  * Come here to wait for space in outq,
 403                                  * or space in rawq, or an empty canq.
 404                                  */
 405                                 wakeup(TSA_HUP_OR_INPUT(tp));
 406                                 if ((tp->t_state & TS_CONNECTED) == 0) {
 407                                         /*
 408                                          * Data piled up because not connected.
 409                                          * Adjust for data copied in but
 410                                          * not written.
 411                                          */
 412                                         uio->uio_resid += cc;
 413                                         lwkt_reltoken(&tty_token);
 414                                         return (EIO);
 415                                 }
 416                                 if (ap->a_ioflag & IO_NDELAY) {
 417                                         /*
 418                                          * Don't wait if asked not to.
 419                                          * Adjust for data copied in but
 420                                          * not written.
 421                                          */
 422                                         uio->uio_resid += cc;
 423                                         if (cnt == 0) {
 424                                                 lwkt_reltoken(&tty_token);
 425                                                 return (EWOULDBLOCK);
 426                                         }
 427                                         lwkt_reltoken(&tty_token);
 428                                         return (0);
 429                                 }
 430                                 error = tsleep(TSA_PTC_WRITE(tp),
 431                                                 PCATCH, "nmdout", 0);
 432                                 if (error) {
 433                                         /*
 434                                          * Tsleep returned (signal?).
 435                                          * Go find out what the user wants.
 436                                          * adjust for data copied in but
 437                                          * not written
 438                                          */
 439                                         uio->uio_resid += cc;
 440                                         lwkt_reltoken(&tty_token);
 441                                         return (error);
 442                                 }
 443                                 goto again;
 444                         }
 445                         (*linesw[tp->t_line].l_rint)(*cp++, tp);
 446                         cnt++;
 447                         cc--;
 448                 }
 449                 cc = 0;
 450         }
 451         lwkt_reltoken(&tty_token);
 452         return (0);
 453 }
 454
 455 /*
 456  * Start output on pseudo-tty.
 457  * Wake up process selecting or sleeping for input from controlling tty.
 458  */
 459 static void
 460 nmdmstart(struct tty *tp)
 461 {
 462         struct nm_softc *pti = tp->t_dev->si_drv1;
 463
 464         lwkt_gettoken(&tty_token);
 465         if (tp->t_state & TS_TTSTOP) {
 466                 lwkt_reltoken(&tty_token);
 467                 return;
 468         }
 469         pti->pt_flags &= ~PF_STOPPED;
 470         wakeup_other(tp, FREAD);
 471         lwkt_reltoken(&tty_token);
 472 }
 473
 474 /* Wakes up the OTHER tty;*/
 475 static void
 476 wakeup_other(struct tty *tp, int flag)
 477 {
 478         struct softpart *ourpart, *otherpart;
 479
 480         lwkt_gettoken(&tty_token);
 481         GETPARTS(tp, ourpart, otherpart);
 482         if (flag & FREAD) {
 483                 wakeup(TSA_PTC_READ((&otherpart->nm_tty)));
 484                 KNOTE(&otherpart->nm_tty.t_rkq.ki_note, 0);
 485         }
 486         if (flag & FWRITE) {
 487                 wakeup(TSA_PTC_WRITE((&otherpart->nm_tty)));
 488                 KNOTE(&otherpart->nm_tty.t_wkq.ki_note, 0);
 489         }
 490         lwkt_reltoken(&tty_token);
 491 }
 492
 493 static  void
 494 nmdmstop(struct tty *tp, int flush)
 495 {
 496         struct nm_softc *pti = tp->t_dev->si_drv1;
 497         int flag;
 498
 499         lwkt_gettoken(&tty_token);
 500         /* note: FLUSHREAD and FLUSHWRITE already ok */
 501         if (flush == 0) {
 502                 flush = TIOCPKT_STOP;
 503                 pti->pt_flags |= PF_STOPPED;
 504         } else
 505                 pti->pt_flags &= ~PF_STOPPED;
 506         /* change of perspective */
 507         flag = 0;
 508         if (flush & FREAD)
 509                 flag |= FWRITE;
 510         if (flush & FWRITE)
 511                 flag |= FREAD;
 512         wakeup_other(tp, flag);
 513         lwkt_reltoken(&tty_token);
 514 }
 515
 516 /*ARGSUSED*/
 517 static  int
 518 nmdmioctl(struct dev_ioctl_args *ap)
 519 {
 520         cdev_t dev = ap->a_head.a_dev;
 521         struct tty *tp = dev->si_tty;
 522         struct nm_softc *pti = dev->si_drv1;
 523         int error;
 524         struct tty *tp2;
 525         struct softpart *ourpart, *otherpart;
 526
 527         crit_enter();
 528         lwkt_gettoken(&tty_token);
 529         GETPARTS(tp, ourpart, otherpart);
 530         tp2 = &otherpart->nm_tty;
 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)