bsd/miscfs/fifofs/fifo_vnops.c

   1 /*
   2  * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  29 /*
  30  * Copyright (c) 1990, 1993, 1995
  31  *      The Regents of the University of California.  All rights reserved.
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 3. All advertising materials mentioning features or use of this software
  42  *    must display the following acknowledgement:
  43  *      This product includes software developed by the University of
  44  *      California, Berkeley and its contributors.
  45  * 4. Neither the name of the University nor the names of its contributors
  46  *    may be used to endorse or promote products derived from this software
  47  *    without specific prior written permission.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  59  * SUCH DAMAGE.
  60  *
  61  *      @(#)fifo_vnops.c        8.4 (Berkeley) 8/10/94
  62  */
  63
  64 #include <sys/param.h>
  65 #include <sys/proc.h>
  66 #include <sys/time.h>
  67 #include <sys/namei.h>
  68 #include <sys/vnode_internal.h>
  69 #include <sys/socket.h>
  70 #include <sys/socketvar.h>
  71 #include <sys/stat.h>
  72 #include <sys/systm.h>
  73 #include <sys/ioctl.h>
  74 #include <sys/file_internal.h>
  75 #include <sys/errno.h>
  76 #include <sys/malloc.h>
  77 #include <miscfs/fifofs/fifo.h>
  78 #include <vfs/vfs_support.h>
  79
  80 #define VOPFUNC int (*)(void *)
  81
  82 int(**fifo_vnodeop_p)(void *);
  83 const struct vnodeopv_entry_desc fifo_vnodeop_entries[] = {
  84         { .opve_op = &vnop_default_desc, .opve_impl = (VOPFUNC)vn_default_error },
  85         { .opve_op = &vnop_lookup_desc, .opve_impl = (VOPFUNC)fifo_lookup },            /* lookup */
  86         { .opve_op = &vnop_create_desc, .opve_impl = (VOPFUNC)err_create },             /* create */
  87         { .opve_op = &vnop_mknod_desc, .opve_impl = (VOPFUNC)err_mknod },               /* mknod */
  88         { .opve_op = &vnop_open_desc, .opve_impl = (VOPFUNC)fifo_open },                        /* open */
  89         { .opve_op = &vnop_close_desc, .opve_impl = (VOPFUNC)fifo_close },              /* close */
  90         { .opve_op = &vnop_access_desc, .opve_impl = (VOPFUNC)fifo_access },            /* access */
  91         { .opve_op = &vnop_getattr_desc, .opve_impl = (VOPFUNC)fifo_getattr },          /* getattr */
  92         { .opve_op = &vnop_setattr_desc, .opve_impl = (VOPFUNC)fifo_setattr },          /* setattr */
  93         { .opve_op = &vnop_read_desc, .opve_impl = (VOPFUNC)fifo_read },                        /* read */
  94         { .opve_op = &vnop_write_desc, .opve_impl = (VOPFUNC)fifo_write },              /* write */
  95         { .opve_op = &vnop_ioctl_desc, .opve_impl = (VOPFUNC)fifo_ioctl },              /* ioctl */
  96         { .opve_op = &vnop_select_desc, .opve_impl = (VOPFUNC)fifo_select },            /* select */
  97         { .opve_op = &vnop_revoke_desc, .opve_impl = (VOPFUNC)fifo_revoke },            /* revoke */
  98         { .opve_op = &vnop_mmap_desc, .opve_impl = (VOPFUNC)err_mmap },                 /* mmap */
  99         { .opve_op = &vnop_fsync_desc, .opve_impl = (VOPFUNC)fifo_fsync },              /* fsync */
 100         { .opve_op = &vnop_remove_desc, .opve_impl = (VOPFUNC)err_remove },             /* remove */
 101         { .opve_op = &vnop_link_desc, .opve_impl = (VOPFUNC)err_link },                 /* link */
 102         { .opve_op = &vnop_rename_desc, .opve_impl = (VOPFUNC)err_rename },             /* rename */
 103         { .opve_op = &vnop_mkdir_desc, .opve_impl = (VOPFUNC)err_mkdir },               /* mkdir */
 104         { .opve_op = &vnop_rmdir_desc, .opve_impl = (VOPFUNC)err_rmdir },               /* rmdir */
 105         { .opve_op = &vnop_symlink_desc, .opve_impl = (VOPFUNC)err_symlink },           /* symlink */
 106         { .opve_op = &vnop_readdir_desc, .opve_impl = (VOPFUNC)err_readdir },           /* readdir */
 107         { .opve_op = &vnop_readlink_desc, .opve_impl = (VOPFUNC)err_readlink },         /* readlink */
 108         { .opve_op = &vnop_inactive_desc, .opve_impl = (VOPFUNC)fifo_inactive },                /* inactive */
 109         { .opve_op = &vnop_reclaim_desc, .opve_impl = (VOPFUNC)fifo_reclaim },          /* reclaim */
 110         { .opve_op = &vnop_strategy_desc, .opve_impl = (VOPFUNC)err_strategy },         /* strategy */
 111         { .opve_op = &vnop_pathconf_desc, .opve_impl = (VOPFUNC)fifo_pathconf },                /* pathconf */
 112         { .opve_op = &vnop_advlock_desc, .opve_impl = (VOPFUNC)fifo_advlock },          /* advlock */
 113         { .opve_op = &vnop_bwrite_desc, .opve_impl = (VOPFUNC)fifo_bwrite },            /* bwrite */
 114         { .opve_op = &vnop_pagein_desc, .opve_impl = (VOPFUNC)err_pagein },             /* Pagein */
 115         { .opve_op = &vnop_pageout_desc, .opve_impl = (VOPFUNC)err_pageout },           /* Pageout */
 116         { .opve_op = &vnop_copyfile_desc, .opve_impl = (VOPFUNC)err_copyfile },         /* Copyfile */
 117         { .opve_op = &vnop_blktooff_desc, .opve_impl = (VOPFUNC)err_blktooff },         /* blktooff */
 118         { .opve_op = &vnop_offtoblk_desc, .opve_impl = (VOPFUNC)err_offtoblk },         /* offtoblk */
 119         { .opve_op = &vnop_blockmap_desc, .opve_impl = (VOPFUNC)err_blockmap },                 /* blockmap */
 120         { .opve_op = (struct vnodeop_desc*)NULL, .opve_impl = (int (*)(void *))NULL }
 121 };
 122 const struct vnodeopv_desc fifo_vnodeop_opv_desc =
 123 { .opv_desc_vector_p = &fifo_vnodeop_p, .opv_desc_ops = fifo_vnodeop_entries };
 124
 125 /*
 126  * Trivial lookup routine that always fails.
 127  */
 128 /* ARGSUSED */
 129 int
 130 fifo_lookup(struct vnop_lookup_args *ap)
 131 {
 132         *ap->a_vpp = NULL;
 133         return ENOTDIR;
 134 }
 135
 136 /*
 137  * Open called to set up a new instance of a fifo or
 138  * to find an active instance of a fifo.
 139  */
 140 /* ARGSUSED */
 141 int
 142 fifo_open(struct vnop_open_args *ap)
 143 {
 144         struct vnode *vp = ap->a_vp;
 145         struct fifoinfo *fip;
 146         struct socket *rso, *wso;
 147         int error;
 148
 149         vnode_lock(vp);
 150
 151 retry:
 152
 153         fip = vp->v_fifoinfo;
 154
 155         if (fip == (struct fifoinfo *)0) {
 156                 panic("fifo_open with no fifoinfo");
 157         }
 158
 159         if ((fip->fi_flags & FIFO_CREATED) == 0) {
 160                 if (fip->fi_flags & FIFO_INCREATE) {
 161                         fip->fi_flags |= FIFO_CREATEWAIT;
 162                         error = msleep(&fip->fi_flags, &vp->v_lock, PRIBIO | PCATCH, "fifocreatewait", NULL);
 163                         if (error) {
 164                                 vnode_unlock(vp);
 165                                 return error;
 166                         }
 167                         goto retry;
 168                 } else {
 169                         fip->fi_flags |= FIFO_INCREATE;
 170                         vnode_unlock(vp);
 171                         if ((error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0))) {
 172                                 goto bad1;
 173                         }
 174
 175                         if ((error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0))) {
 176                                 (void)soclose(rso);
 177                                 goto bad1;
 178                         }
 179
 180                         if ((error = soconnect2(wso, rso))) {
 181                                 (void)soclose(wso);
 182                                 (void)soclose(rso);
 183                                 goto bad1;
 184                         }
 185                         fip->fi_readers = fip->fi_writers = 0;
 186
 187                         /* Lock ordering between wso and rso does not matter here
 188                          * because they are just created and no one has a reference to them
 189                          */
 190                         socket_lock(wso, 1);
 191                         wso->so_state |= SS_CANTRCVMORE;
 192                         wso->so_snd.sb_lowat = PIPE_BUF;
 193                         socket_unlock(wso, 1);
 194
 195                         socket_lock(rso, 1);
 196                         rso->so_state |= SS_CANTSENDMORE;
 197                         socket_unlock(rso, 1);
 198
 199                         vnode_lock(vp);
 200                         fip->fi_readsock = rso;
 201                         fip->fi_writesock = wso;
 202
 203                         fip->fi_flags |= FIFO_CREATED;
 204                         fip->fi_flags &= ~FIFO_INCREATE;
 205
 206                         if ((fip->fi_flags & FIFO_CREATEWAIT)) {
 207                                 fip->fi_flags &= ~FIFO_CREATEWAIT;
 208                                 wakeup(&fip->fi_flags);
 209                         }
 210                         /* vnode lock is held  to process further */
 211                 }
 212         }
 213
 214         /* vnode is locked at this point */
 215         /* fifo in created already */
 216         if (ap->a_mode & FREAD) {
 217                 fip->fi_readers++;
 218                 if (fip->fi_readers == 1) {
 219                         socket_lock(fip->fi_writesock, 1);
 220                         fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
 221                         socket_unlock(fip->fi_writesock, 1);
 222
 223                         if (fip->fi_writers > 0) {
 224                                 wakeup((caddr_t)&fip->fi_writers);
 225                         }
 226                 }
 227         }
 228         if (ap->a_mode & FWRITE) {
 229                 fip->fi_writers++;
 230                 if (fip->fi_writers == 1) {
 231                         socket_lock(fip->fi_readsock, 1);
 232                         fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
 233                         socket_unlock(fip->fi_readsock, 1);
 234
 235                         if (fip->fi_readers > 0) {
 236                                 wakeup((caddr_t)&fip->fi_readers);
 237                         }
 238                 }
 239         }
 240         if ((ap->a_mode & FREAD) && (ap->a_mode & O_NONBLOCK) == 0) {
 241                 if (fip->fi_writers == 0) {
 242                         error = msleep((caddr_t)&fip->fi_readers, &vp->v_lock,
 243                             PCATCH | PSOCK, "fifoor", NULL);
 244                         if (error) {
 245                                 goto bad;
 246                         }
 247                         if (fip->fi_readers == 1) {
 248                                 if (fip->fi_writers > 0) {
 249                                         wakeup((caddr_t)&fip->fi_writers);
 250                                 }
 251                         }
 252                 }
 253         }
 254         if (ap->a_mode & FWRITE) {
 255                 if (ap->a_mode & O_NONBLOCK) {
 256                         if (fip->fi_readers == 0) {
 257                                 error = ENXIO;
 258                                 goto bad;
 259                         }
 260                 } else {
 261                         if (fip->fi_readers == 0) {
 262                                 error = msleep((caddr_t)&fip->fi_writers, &vp->v_lock,
 263                                     PCATCH | PSOCK, "fifoow", NULL);
 264                                 if (error) {
 265                                         goto bad;
 266                                 }
 267                                 if (fip->fi_writers == 1) {
 268                                         if (fip->fi_readers > 0) {
 269                                                 wakeup((caddr_t)&fip->fi_readers);
 270                                         }
 271                                 }
 272                         }
 273                 }
 274         }
 275
 276         vnode_unlock(vp);
 277         return 0;
 278 bad:
 279         fifo_close_internal(vp, ap->a_mode, ap->a_context, 1);
 280
 281         vnode_unlock(vp);
 282         return error;
 283 bad1:
 284         vnode_lock(vp);
 285
 286         fip->fi_flags &= ~FIFO_INCREATE;
 287
 288         if ((fip->fi_flags & FIFO_CREATEWAIT)) {
 289                 fip->fi_flags &= ~FIFO_CREATEWAIT;
 290                 wakeup(&fip->fi_flags);
 291         }
 292         vnode_unlock(vp);
 293
 294         return error;
 295 }
 296
 297 /*
 298  * Vnode op for read
 299  */
 300 int
 301 fifo_read(struct vnop_read_args *ap)
 302 {
 303         struct uio *uio = ap->a_uio;
 304         struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
 305         user_ssize_t startresid;
 306         int error;
 307         int rflags;
 308
 309 #if DIAGNOSTIC
 310         if (uio->uio_rw != UIO_READ) {
 311                 panic("fifo_read mode");
 312         }
 313 #endif
 314         if (uio_resid(uio) == 0) {
 315                 return 0;
 316         }
 317
 318         rflags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0;
 319
 320         startresid = uio_resid(uio);
 321
 322         /* fifo conformance - if we have a reader open on the fifo but no
 323          * writers then we need to make sure we do not block.  We do that by
 324          * checking the receive buffer and if empty set error to EWOULDBLOCK.
 325          * If error is set to EWOULDBLOCK we skip the call into soreceive
 326          */
 327         error = 0;
 328         if (ap->a_vp->v_fifoinfo->fi_writers < 1) {
 329                 socket_lock(rso, 1);
 330                 error = (rso->so_rcv.sb_cc == 0) ? EWOULDBLOCK : 0;
 331                 socket_unlock(rso, 1);
 332         }
 333
 334         /* skip soreceive to avoid blocking when we have no writers */
 335         if (error != EWOULDBLOCK) {
 336                 error = soreceive(rso, (struct sockaddr **)0, uio, (struct mbuf **)0,
 337                     (struct mbuf **)0, &rflags);
 338                 if (error == 0) {
 339                         lock_vnode_and_post(ap->a_vp, 0);
 340                 }
 341         } else {
 342                 /* clear EWOULDBLOCK and return EOF (zero) */
 343                 error = 0;
 344         }
 345         /*
 346          * Clear EOF indication after first such return.
 347          */
 348         if (uio_resid(uio) == startresid) {
 349                 socket_lock(rso, 1);
 350                 rso->so_state &= ~SS_CANTRCVMORE;
 351                 socket_unlock(rso, 1);
 352         }
 353         return error;
 354 }
 355
 356 /*
 357  * Vnode op for write
 358  */
 359 int
 360 fifo_write(struct vnop_write_args *ap)
 361 {
 362         struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
 363         int error;
 364
 365 #if DIAGNOSTIC
 366         if (ap->a_uio->uio_rw != UIO_WRITE) {
 367                 panic("fifo_write mode");
 368         }
 369 #endif
 370         error = sosend(wso, (struct sockaddr *)0, ap->a_uio, NULL,
 371             (struct mbuf *)0, (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0);
 372         if (error == 0) {
 373                 lock_vnode_and_post(ap->a_vp, 0);
 374         }
 375
 376         return error;
 377 }
 378
 379 /*
 380  * Device ioctl operation.
 381  */
 382 int
 383 fifo_ioctl(struct vnop_ioctl_args *ap)
 384 {
 385         struct fileproc filetmp;
 386         struct fileglob filefg;
 387         int error;
 388
 389         if (ap->a_command == FIONBIO) {
 390                 return 0;
 391         }
 392         bzero(&filetmp, sizeof(struct fileproc));
 393         filetmp.f_fglob = &filefg;
 394         if (ap->a_fflag & FREAD) {
 395                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
 396                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_context);
 397                 if (error) {
 398                         return error;
 399                 }
 400         }
 401         if (ap->a_fflag & FWRITE) {
 402                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
 403                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_context);
 404                 if (error) {
 405                         return error;
 406                 }
 407         }
 408         return 0;
 409 }
 410
 411 int
 412 fifo_select(struct vnop_select_args *ap)
 413 {
 414         struct fileproc filetmp;
 415         struct fileglob filefg;
 416         int ready;
 417
 418         bzero(&filetmp, sizeof(struct fileproc));
 419         filetmp.f_fglob = &filefg;
 420         if (ap->a_which & FREAD) {
 421                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
 422                 ready = soo_select(&filetmp, ap->a_which, ap->a_wql, ap->a_context);
 423                 if (ready) {
 424                         return ready;
 425                 }
 426         }
 427         if (ap->a_which & FWRITE) {
 428                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
 429                 ready = soo_select(&filetmp, ap->a_which, ap->a_wql, ap->a_context);
 430                 if (ready) {
 431                         return ready;
 432                 }
 433         }
 434         return 0;
 435 }
 436
 437 int
 438 fifo_inactive(__unused struct vnop_inactive_args *ap)
 439 {
 440         return 0;
 441 }
 442
 443
 444 /*
 445  * Device close routine
 446  */
 447 int
 448 fifo_close(struct vnop_close_args *ap)
 449 {
 450         return fifo_close_internal(ap->a_vp, ap->a_fflag, ap->a_context, 0);
 451 }
 452
 453 int
 454 fifo_close_internal(vnode_t vp, int fflag, __unused vfs_context_t context, int locked)
 455 {
 456         struct fifoinfo *fip = vp->v_fifoinfo;
 457         int error1, error2;
 458         struct socket *rso;
 459         struct socket *wso;
 460
 461         if (!locked) {
 462                 vnode_lock(vp);
 463         }
 464
 465         if ((fip->fi_flags & FIFO_CREATED) == 0) {
 466                 if (!locked) {
 467                         vnode_unlock(vp);
 468                 }
 469                 return 0;
 470         }
 471
 472         if (fflag & FREAD) {
 473                 fip->fi_readers--;
 474                 if (fip->fi_readers == 0) {
 475                         socket_lock(fip->fi_writesock, 1);
 476                         socantsendmore(fip->fi_writesock);
 477                         socket_unlock(fip->fi_writesock, 1);
 478                 }
 479         }
 480
 481         if (fflag & FWRITE) {
 482                 fip->fi_writers--;
 483                 if (fip->fi_writers == 0) {
 484                         socket_lock(fip->fi_readsock, 1);
 485                         socantrcvmore(fip->fi_readsock);
 486                         socket_unlock(fip->fi_readsock, 1);
 487                 }
 488         }
 489 #if 0
 490         if (vnode_isinuse_locked(vp, 0, 1)) {
 491                 if (!locked) {
 492                         vnode_unlock(vp);
 493                 }
 494                 return 0;
 495         }
 496 #endif
 497
 498         if (fip->fi_writers || fip->fi_readers) {
 499                 if (!locked) {
 500                         vnode_unlock(vp);
 501                 }
 502                 return 0;
 503         }
 504
 505         wso = fip->fi_writesock;
 506         rso = fip->fi_readsock;
 507         fip->fi_readsock = NULL;
 508         fip->fi_writesock = NULL;
 509         fip->fi_flags &= ~FIFO_CREATED;
 510         if (!locked) {
 511                 vnode_unlock(vp);
 512         }
 513         error1 = soclose(rso);
 514         error2 = soclose(wso);
 515
 516         if (error1) {
 517                 return error1;
 518         }
 519         return error2;
 520 }
 521
 522 /*
 523  * Print out internal contents of a fifo vnode.
 524  */
 525 void
 526 fifo_printinfo(struct vnode *vp)
 527 {
 528         struct fifoinfo *fip = vp->v_fifoinfo;
 529
 530         printf(", fifo with %ld readers and %ld writers",
 531             fip->fi_readers, fip->fi_writers);
 532 }
 533
 534 /*
 535  * Return POSIX pathconf information applicable to fifo's.
 536  */
 537 int
 538 fifo_pathconf(struct vnop_pathconf_args *ap)
 539 {
 540         switch (ap->a_name) {
 541         case _PC_LINK_MAX:
 542                 *ap->a_retval = LINK_MAX;
 543                 return 0;
 544         case _PC_PIPE_BUF:
 545                 *ap->a_retval = PIPE_BUF;
 546                 return 0;
 547         case _PC_CHOWN_RESTRICTED:
 548                 *ap->a_retval = 200112;         /* _POSIX_CHOWN_RESTRICTED */
 549                 return 0;
 550         default:
 551                 return EINVAL;
 552         }
 553         /* NOTREACHED */
 554 }
 555
 556 /*
 557  * Fifo failed operation
 558  */
 559 int
 560 fifo_ebadf(__unused void *dummy)
 561 {
 562         return EBADF;
 563 }
 564
 565 /*
 566  * Fifo advisory byte-level locks.
 567  */
 568 int
 569 fifo_advlock(__unused struct vnop_advlock_args *ap)
 570 {
 571         return ENOTSUP;
 572 }
 573
 574
 575 /* You'd certainly better have an iocount on the vnode! */
 576 int
 577 fifo_freespace(struct vnode *vp, long *count)
 578 {
 579         struct socket *rsock;
 580         rsock = vp->v_fifoinfo->fi_readsock;
 581         socket_lock(rsock, 1);
 582         *count = sbspace(&rsock->so_rcv);
 583         socket_unlock(rsock, 1);
 584         return 0;
 585 }
 586
 587 int
 588 fifo_charcount(struct vnode *vp, int *count)
 589 {
 590         int mcount;
 591         int err = sock_ioctl(vp->v_fifoinfo->fi_readsock, FIONREAD, (void*)&mcount);
 592         if (err == 0) {
 593                 *count = mcount;
 594         }
 595         return err;
 596 }