sys/vfs/fifofs/fifo_vnops.c

   1 /*
   2  * Copyright (c) 1990, 1993, 1995
   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  *      @(#)fifo_vnops.c        8.10 (Berkeley) 5/27/95
  34  * $FreeBSD: src/sys/miscfs/fifofs/fifo_vnops.c,v 1.45.2.4 2003/04/22 10:11:24 bde Exp $
  35  * $DragonFly: src/sys/vfs/fifofs/fifo_vnops.c,v 1.40 2007/08/13 17:31:56 dillon Exp $
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/systm.h>
  40 #include <sys/unistd.h>
  41 #include <sys/kernel.h>
  42 #include <sys/lock.h>
  43 #include <sys/malloc.h>
  44 #include <sys/thread2.h>
  45 #include <sys/vnode.h>
  46 #include <sys/socket.h>
  47 #include <sys/socketvar.h>
  48 #include <sys/filio.h>
  49 #include <sys/fcntl.h>
  50 #include <sys/file.h>
  51 #include <sys/event.h>
  52 #include <sys/poll.h>
  53 #include <sys/un.h>
  54
  55 #include <sys/thread2.h>
  56
  57 #include "fifo.h"
  58
  59 /*
  60  * This structure is associated with the FIFO vnode and stores
  61  * the state associated with the FIFO.
  62  */
  63 struct fifoinfo {
  64         struct socket   *fi_readsock;
  65         struct socket   *fi_writesock;
  66         long            fi_readers;
  67         long            fi_writers;
  68 };
  69
  70 static int      fifo_badop (void);
  71 static int      fifo_print (struct vop_print_args *);
  72 static int      fifo_lookup (struct vop_old_lookup_args *);
  73 static int      fifo_open (struct vop_open_args *);
  74 static int      fifo_close (struct vop_close_args *);
  75 static int      fifo_read (struct vop_read_args *);
  76 static int      fifo_write (struct vop_write_args *);
  77 static int      fifo_ioctl (struct vop_ioctl_args *);
  78 static int      fifo_poll (struct vop_poll_args *);
  79 static int      fifo_kqfilter (struct vop_kqfilter_args *);
  80 static int      fifo_inactive (struct  vop_inactive_args *);
  81 static int      fifo_bmap (struct vop_bmap_args *);
  82 static int      fifo_pathconf (struct vop_pathconf_args *);
  83 static int      fifo_advlock (struct vop_advlock_args *);
  84
  85 static void     filt_fifordetach(struct knote *kn);
  86 static int      filt_fiforead(struct knote *kn, long hint);
  87 static void     filt_fifowdetach(struct knote *kn);
  88 static int      filt_fifowrite(struct knote *kn, long hint);
  89
  90 static struct filterops fiforead_filtops =
  91         { 1, NULL, filt_fifordetach, filt_fiforead };
  92 static struct filterops fifowrite_filtops =
  93         { 1, NULL, filt_fifowdetach, filt_fifowrite };
  94
  95 struct vop_ops fifo_vnode_vops = {
  96         .vop_default =          vop_defaultop,
  97         .vop_access =           (void *)vop_ebadf,
  98         .vop_advlock =          fifo_advlock,
  99         .vop_bmap =             fifo_bmap,
 100         .vop_close =            fifo_close,
 101         .vop_old_create =       (void *)fifo_badop,
 102         .vop_getattr =          (void *)vop_ebadf,
 103         .vop_inactive =         fifo_inactive,
 104         .vop_ioctl =            fifo_ioctl,
 105         .vop_kqfilter =         fifo_kqfilter,
 106         .vop_old_link =         (void *)fifo_badop,
 107         .vop_old_lookup =       fifo_lookup,
 108         .vop_old_mkdir =        (void *)fifo_badop,
 109         .vop_old_mknod =        (void *)fifo_badop,
 110         .vop_open =             fifo_open,
 111         .vop_pathconf =         fifo_pathconf,
 112         .vop_poll =             fifo_poll,
 113         .vop_print =            fifo_print,
 114         .vop_read =             fifo_read,
 115         .vop_readdir =          (void *)fifo_badop,
 116         .vop_readlink =         (void *)fifo_badop,
 117         .vop_reallocblks =      (void *)fifo_badop,
 118         .vop_reclaim =          (void *)vop_null,
 119         .vop_old_remove =       (void *)fifo_badop,
 120         .vop_old_rename =       (void *)fifo_badop,
 121         .vop_old_rmdir =        (void *)fifo_badop,
 122         .vop_setattr =          (void *)vop_ebadf,
 123         .vop_old_symlink =      (void *)fifo_badop,
 124         .vop_write =            fifo_write
 125 };
 126
 127 VNODEOP_SET(fifo_vnode_vops);
 128
 129 static MALLOC_DEFINE(M_FIFOINFO, "Fifo info", "Fifo info entries");
 130
 131 /*
 132  * fifo_vnoperate()
 133  */
 134 int
 135 fifo_vnoperate(struct vop_generic_args *ap)
 136 {
 137         return (VOCALL(&fifo_vnode_vops, ap));
 138 }
 139
 140 /*
 141  * Trivial lookup routine that always fails.
 142  *
 143  * fifo_lookup(struct vnode *a_dvp, struct vnode **a_vpp,
 144  *             struct componentname *a_cnp)
 145  */
 146 /* ARGSUSED */
 147 static int
 148 fifo_lookup(struct vop_old_lookup_args *ap)
 149 {
 150         *ap->a_vpp = NULL;
 151         return (ENOTDIR);
 152 }
 153
 154 /*
 155  * Open called to set up a new instance of a fifo or
 156  * to find an active instance of a fifo.
 157  *
 158  * fifo_open(struct vnode *a_vp, int a_mode, struct ucred *a_cred,
 159  *           struct file *a_fp)
 160  */
 161 /* ARGSUSED */
 162 static int
 163 fifo_open(struct vop_open_args *ap)
 164 {
 165         struct thread *td = curthread;
 166         struct vnode *vp = ap->a_vp;
 167         struct fifoinfo *fip;
 168         struct socket *rso, *wso;
 169         int error;
 170
 171         if ((fip = vp->v_fifoinfo) == NULL) {
 172                 MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_FIFOINFO, M_WAITOK);
 173                 vp->v_fifoinfo = fip;
 174                 error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0, td);
 175                 if (error) {
 176                         kfree(fip, M_FIFOINFO);
 177                         vp->v_fifoinfo = NULL;
 178                         return (error);
 179                 }
 180                 fip->fi_readsock = rso;
 181                 error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0, td);
 182                 if (error) {
 183                         soclose(rso, FNONBLOCK);
 184                         kfree(fip, M_FIFOINFO);
 185                         vp->v_fifoinfo = NULL;
 186                         return (error);
 187                 }
 188                 fip->fi_writesock = wso;
 189                 error = unp_connect2(wso, rso);
 190                 if (error) {
 191                         soclose(wso, FNONBLOCK);
 192                         soclose(rso, FNONBLOCK);
 193                         kfree(fip, M_FIFOINFO);
 194                         vp->v_fifoinfo = NULL;
 195                         return (error);
 196                 }
 197                 fip->fi_readers = fip->fi_writers = 0;
 198                 wso->so_snd.ssb_lowat = PIPE_BUF;
 199                 rso->so_state |= SS_CANTRCVMORE;
 200         }
 201         if (ap->a_mode & FREAD) {
 202                 fip->fi_readers++;
 203                 if (fip->fi_readers == 1) {
 204                         fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
 205                         if (fip->fi_writers > 0) {
 206                                 wakeup((caddr_t)&fip->fi_writers);
 207                                 sowwakeup(fip->fi_writesock);
 208                         }
 209                 }
 210         }
 211         if (ap->a_mode & FWRITE) {
 212                 fip->fi_writers++;
 213                 if (fip->fi_writers == 1) {
 214                         fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
 215                         if (fip->fi_readers > 0) {
 216                                 wakeup((caddr_t)&fip->fi_readers);
 217                                 sorwakeup(fip->fi_writesock);
 218                         }
 219                 }
 220         }
 221         if ((ap->a_mode & FREAD) && (ap->a_mode & O_NONBLOCK) == 0) {
 222                 if (fip->fi_writers == 0) {
 223                         vn_unlock(vp);
 224                         error = tsleep((caddr_t)&fip->fi_readers,
 225                             PCATCH, "fifoor", 0);
 226                         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 227                         if (error)
 228                                 goto bad;
 229                         /*
 230                          * We must have got woken up because we had a writer.
 231                          * That (and not still having one) is the condition
 232                          * that we must wait for.
 233                          */
 234                 }
 235         }
 236         if (ap->a_mode & FWRITE) {
 237                 if (ap->a_mode & O_NONBLOCK) {
 238                         if (fip->fi_readers == 0) {
 239                                 error = ENXIO;
 240                                 goto bad;
 241                         }
 242                 } else {
 243                         if (fip->fi_readers == 0) {
 244                                 vn_unlock(vp);
 245                                 error = tsleep((caddr_t)&fip->fi_writers,
 246                                     PCATCH, "fifoow", 0);
 247                                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 248                                 if (error)
 249                                         goto bad;
 250                                 /*
 251                                  * We must have got woken up because we had
 252                                  * a reader.  That (and not still having one)
 253                                  * is the condition that we must wait for.
 254                                  */
 255                         }
 256                 }
 257         }
 258         return (vop_stdopen(ap));
 259 bad:
 260         vop_stdopen(ap);        /* bump opencount/writecount as appropriate */
 261         VOP_CLOSE(vp, ap->a_mode);
 262         return (error);
 263 }
 264
 265 /*
 266  * Vnode op for read
 267  *
 268  * fifo_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
 269  *           struct ucred *a_cred)
 270  */
 271 /* ARGSUSED */
 272 static int
 273 fifo_read(struct vop_read_args *ap)
 274 {
 275         struct uio *uio = ap->a_uio;
 276         struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
 277         int error, startresid;
 278         int flags;
 279
 280 #ifdef DIAGNOSTIC
 281         if (uio->uio_rw != UIO_READ)
 282                 panic("fifo_read mode");
 283 #endif
 284         if (uio->uio_resid == 0)
 285                 return (0);
 286         if (ap->a_ioflag & IO_NDELAY)
 287                 flags = MSG_FNONBLOCKING;
 288         else
 289                 flags = 0;
 290         startresid = uio->uio_resid;
 291         vn_unlock(ap->a_vp);
 292         error = soreceive(rso, NULL, uio, NULL, NULL, &flags);
 293         vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
 294         return (error);
 295 }
 296
 297 /*
 298  * Vnode op for write
 299  *
 300  * fifo_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
 301  *            struct ucred *a_cred)
 302  */
 303 /* ARGSUSED */
 304 static int
 305 fifo_write(struct vop_write_args *ap)
 306 {
 307         struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
 308         struct thread *td = ap->a_uio->uio_td;
 309         int error;
 310         int flags;
 311
 312 #ifdef DIAGNOSTIC
 313         if (ap->a_uio->uio_rw != UIO_WRITE)
 314                 panic("fifo_write mode");
 315 #endif
 316         if (ap->a_ioflag & IO_NDELAY)
 317                 flags = MSG_FNONBLOCKING;
 318         else
 319                 flags = 0;
 320         vn_unlock(ap->a_vp);
 321         error = sosend(wso, NULL, ap->a_uio, 0, NULL, flags, td);
 322         vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
 323         return (error);
 324 }
 325
 326 /*
 327  * Device ioctl operation.
 328  *
 329  * fifo_ioctl(struct vnode *a_vp, int a_command, caddr_t a_data, int a_fflag,
 330  *            struct ucred *a_cred)
 331  */
 332 /* ARGSUSED */
 333 static int
 334 fifo_ioctl(struct vop_ioctl_args *ap)
 335 {
 336         struct file filetmp;    /* Local */
 337         int error;
 338
 339         if (ap->a_fflag & FREAD) {
 340                 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock;
 341                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_cred);
 342                 if (error)
 343                         return (error);
 344         }
 345         if (ap->a_fflag & FWRITE) {
 346                 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock;
 347                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_cred);
 348                 if (error)
 349                         return (error);
 350         }
 351         return (0);
 352 }
 353
 354 /*
 355  * fifo_kqfilter(struct vnode *a_vp, struct knote *a_kn)
 356  */
 357 /* ARGSUSED */
 358 static int
 359 fifo_kqfilter(struct vop_kqfilter_args *ap)
 360 {
 361         struct fifoinfo *fi = ap->a_vp->v_fifoinfo;
 362         struct socket *so;
 363         struct signalsockbuf *ssb;
 364
 365         switch (ap->a_kn->kn_filter) {
 366         case EVFILT_READ:
 367                 ap->a_kn->kn_fop = &fiforead_filtops;
 368                 so = fi->fi_readsock;
 369                 ssb = &so->so_rcv;
 370                 break;
 371         case EVFILT_WRITE:
 372                 ap->a_kn->kn_fop = &fifowrite_filtops;
 373                 so = fi->fi_writesock;
 374                 ssb = &so->so_snd;
 375                 break;
 376         default:
 377                 return (1);
 378         }
 379
 380         ap->a_kn->kn_hook = (caddr_t)so;
 381
 382         ssb_insert_knote(ssb, ap->a_kn);
 383
 384         return (0);
 385 }
 386
 387 static void
 388 filt_fifordetach(struct knote *kn)
 389 {
 390         struct socket *so = (struct socket *)kn->kn_hook;
 391
 392         ssb_remove_knote(&so->so_rcv, kn);
 393 }
 394
 395 static int
 396 filt_fiforead(struct knote *kn, long hint)
 397 {
 398         struct socket *so = (struct socket *)kn->kn_hook;
 399
 400         kn->kn_data = so->so_rcv.ssb_cc;
 401         if (so->so_state & SS_CANTRCVMORE) {
 402                 kn->kn_flags |= EV_EOF;
 403                 return (1);
 404         }
 405         kn->kn_flags &= ~EV_EOF;
 406         return (kn->kn_data > 0);
 407 }
 408
 409 static void
 410 filt_fifowdetach(struct knote *kn)
 411 {
 412         struct socket *so = (struct socket *)kn->kn_hook;
 413
 414         ssb_remove_knote(&so->so_snd, kn);
 415 }
 416
 417 static int
 418 filt_fifowrite(struct knote *kn, long hint)
 419 {
 420         struct socket *so = (struct socket *)kn->kn_hook;
 421
 422         kn->kn_data = ssb_space(&so->so_snd);
 423         if (so->so_state & SS_CANTSENDMORE) {
 424                 kn->kn_flags |= EV_EOF;
 425                 return (1);
 426         }
 427         kn->kn_flags &= ~EV_EOF;
 428         return (kn->kn_data >= so->so_snd.ssb_lowat);
 429 }
 430
 431 /*
 432  * fifo_poll(struct vnode *a_vp, int a_events, struct ucred *a_cred)
 433  */
 434 /* ARGSUSED */
 435 static int
 436 fifo_poll(struct vop_poll_args *ap)
 437 {
 438         struct file filetmp;
 439         int events, revents = 0;
 440
 441         events = ap->a_events &
 442                 (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND);
 443         if (events) {
 444                 /*
 445                  * If POLLIN or POLLRDNORM is requested and POLLINIGNEOF is
 446                  * not, then convert the first two to the last one.  This
 447                  * tells the socket poll function to ignore EOF so that we
 448                  * block if there is no writer (and no data).  Callers can
 449                  * set POLLINIGNEOF to get non-blocking behavior.
 450                  */
 451                 if (events & (POLLIN | POLLRDNORM) &&
 452                         !(events & POLLINIGNEOF)) {
 453                         events &= ~(POLLIN | POLLRDNORM);
 454                         events |= POLLINIGNEOF;
 455                 }
 456
 457                 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock;
 458                 if (filetmp.f_data)
 459                         revents |= soo_poll(&filetmp, events, ap->a_cred);
 460
 461                 /* Reverse the above conversion. */
 462                 if ((revents & POLLINIGNEOF) &&
 463                         !(ap->a_events & POLLINIGNEOF)) {
 464                         revents |= (ap->a_events & (POLLIN | POLLRDNORM));
 465                         revents &= ~POLLINIGNEOF;
 466                 }
 467         }
 468         events = ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND);
 469         if (events) {
 470                 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock;
 471                 if (filetmp.f_data)
 472                         revents |= soo_poll(&filetmp, events, ap->a_cred);
 473         }
 474         return (revents);
 475 }
 476
 477 /*
 478  * fifo_inactive(struct vnode *a_vp)
 479  */
 480 static int
 481 fifo_inactive(struct vop_inactive_args *ap)
 482 {
 483         return (0);
 484 }
 485
 486 /*
 487  * This is a noop, simply returning what one has been given.
 488  *
 489  * fifo_bmap(struct vnode *a_vp, off_t a_loffset,
 490  *           off_t *a_doffsetp, int *a_runp, int *a_runb)
 491  */
 492 static int
 493 fifo_bmap(struct vop_bmap_args *ap)
 494 {
 495         if (ap->a_doffsetp != NULL)
 496                 *ap->a_doffsetp = ap->a_loffset;
 497         if (ap->a_runp != NULL)
 498                 *ap->a_runp = 0;
 499         if (ap->a_runb != NULL)
 500                 *ap->a_runb = 0;
 501         return (0);
 502 }
 503
 504 /*
 505  * Device close routine
 506  *
 507  * fifo_close(struct vnode *a_vp, int a_fflag)
 508  */
 509 /* ARGSUSED */
 510 static int
 511 fifo_close(struct vop_close_args *ap)
 512 {
 513         struct vnode *vp = ap->a_vp;
 514         struct fifoinfo *fip = vp->v_fifoinfo;
 515         int error1, error2;
 516
 517         if (ap->a_fflag & FREAD) {
 518                 fip->fi_readers--;
 519                 if (fip->fi_readers == 0)
 520                         socantsendmore(fip->fi_writesock);
 521         }
 522         if (ap->a_fflag & FWRITE) {
 523                 fip->fi_writers--;
 524                 if (fip->fi_writers == 0)
 525                         socantrcvmore(fip->fi_readsock);
 526         }
 527         if (vp->v_sysref.refcnt > 1) {
 528                 vop_stdclose(ap);
 529                 return (0);
 530         }
 531         error1 = soclose(fip->fi_readsock, FNONBLOCK);
 532         error2 = soclose(fip->fi_writesock, FNONBLOCK);
 533         FREE(fip, M_FIFOINFO);
 534         vp->v_fifoinfo = NULL;
 535         if (error1)
 536                 return (error1);
 537         vop_stdclose(ap);
 538         return (error2);
 539 }
 540
 541
 542 /*
 543  * Print out internal contents of a fifo vnode.
 544  */
 545 int
 546 fifo_printinfo(struct vnode *vp)
 547 {
 548         struct fifoinfo *fip = vp->v_fifoinfo;
 549
 550         kprintf(", fifo with %ld readers and %ld writers",
 551                 fip->fi_readers, fip->fi_writers);
 552         return (0);
 553 }
 554
 555 /*
 556  * Print out the contents of a fifo vnode.
 557  *
 558  * fifo_print(struct vnode *a_vp)
 559  */
 560 static int
 561 fifo_print(struct vop_print_args *ap)
 562 {
 563         kprintf("tag VT_NON");
 564         fifo_printinfo(ap->a_vp);
 565         kprintf("\n");
 566         return (0);
 567 }
 568
 569 /*
 570  * Return POSIX pathconf information applicable to fifo's.
 571  *
 572  * fifo_pathconf(struct vnode *a_vp, int a_name, int *a_retval)
 573  */
 574 int
 575 fifo_pathconf(struct vop_pathconf_args *ap)
 576 {
 577         switch (ap->a_name) {
 578         case _PC_LINK_MAX:
 579                 *ap->a_retval = LINK_MAX;
 580                 return (0);
 581         case _PC_PIPE_BUF:
 582                 *ap->a_retval = PIPE_BUF;
 583                 return (0);
 584         case _PC_CHOWN_RESTRICTED:
 585                 *ap->a_retval = 1;
 586                 return (0);
 587         default:
 588                 return (EINVAL);
 589         }
 590         /* NOTREACHED */
 591 }
 592
 593 /*
 594  * Fifo advisory byte-level locks.
 595  *
 596  * fifo_advlock(struct vnode *a_vp, caddr_t a_id, int a_op, struct flock *a_fl,
 597  *              int a_flags)
 598  */
 599 /* ARGSUSED */
 600 static int
 601 fifo_advlock(struct vop_advlock_args *ap)
 602 {
 603         return ((ap->a_flags & F_POSIX) ? EINVAL : EOPNOTSUPP);
 604 }
 605
 606 /*
 607  * Fifo bad operation
 608  */
 609 static int
 610 fifo_badop(void)
 611 {
 612         panic("fifo_badop called");
 613         /* NOTREACHED */
 614 }