bsd/miscfs/fifofs/fifo_vnops.c

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  24 /*
  25  * Copyright (c) 1990, 1993, 1995
  26  *      The Regents of the University of California.  All rights reserved.
  27  *
  28  * Redistribution and use in source and binary forms, with or without
  29  * modification, are permitted provided that the following conditions
  30  * are met:
  31  * 1. Redistributions of source code must retain the above copyright
  32  *    notice, this list of conditions and the following disclaimer.
  33  * 2. Redistributions in binary form must reproduce the above copyright
  34  *    notice, this list of conditions and the following disclaimer in the
  35  *    documentation and/or other materials provided with the distribution.
  36  * 3. All advertising materials mentioning features or use of this software
  37  *    must display the following acknowledgement:
  38  *      This product includes software developed by the University of
  39  *      California, Berkeley and its contributors.
  40  * 4. Neither the name of the University nor the names of its contributors
  41  *    may be used to endorse or promote products derived from this software
  42  *    without specific prior written permission.
  43  *
  44  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  45  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  46  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  47  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  48  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  49  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  50  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  51  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  52  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  53  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  54  * SUCH DAMAGE.
  55  *
  56  *      @(#)fifo_vnops.c        8.4 (Berkeley) 8/10/94
  57  */
  58
  59 #include <sys/param.h>
  60 #include <sys/proc.h>
  61 #include <sys/time.h>
  62 #include <sys/namei.h>
  63 #include <sys/vnode_internal.h>
  64 #include <sys/socket.h>
  65 #include <sys/socketvar.h>
  66 #include <sys/stat.h>
  67 #include <sys/systm.h>
  68 #include <sys/ioctl.h>
  69 #include <sys/file_internal.h>
  70 #include <sys/errno.h>
  71 #include <sys/malloc.h>
  72 #include <miscfs/fifofs/fifo.h>
  73 #include <vfs/vfs_support.h>
  74
  75 #define VOPFUNC int (*)(void *)
  76
  77 extern int      soo_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, struct proc *p);
  78 extern int      soo_select(struct fileproc *fp, int which, void * wql, struct proc *p);
  79
  80 int (**fifo_vnodeop_p)(void *);
  81 struct vnodeopv_entry_desc fifo_vnodeop_entries[] = {
  82         { &vnop_default_desc, (VOPFUNC)vn_default_error },
  83         { &vnop_lookup_desc, (VOPFUNC)fifo_lookup },            /* lookup */
  84         { &vnop_create_desc, (VOPFUNC)err_create },             /* create */
  85         { &vnop_mknod_desc, (VOPFUNC)err_mknod },               /* mknod */
  86         { &vnop_open_desc, (VOPFUNC)fifo_open },                        /* open */
  87         { &vnop_close_desc, (VOPFUNC)fifo_close },              /* close */
  88         { &vnop_access_desc, (VOPFUNC)fifo_access },            /* access */
  89         { &vnop_getattr_desc, (VOPFUNC)fifo_getattr },          /* getattr */
  90         { &vnop_setattr_desc, (VOPFUNC)fifo_setattr },          /* setattr */
  91         { &vnop_read_desc, (VOPFUNC)fifo_read },                        /* read */
  92         { &vnop_write_desc, (VOPFUNC)fifo_write },              /* write */
  93         { &vnop_ioctl_desc, (VOPFUNC)fifo_ioctl },              /* ioctl */
  94         { &vnop_select_desc, (VOPFUNC)fifo_select },            /* select */
  95         { &vnop_revoke_desc, (VOPFUNC)fifo_revoke },            /* revoke */
  96         { &vnop_mmap_desc, (VOPFUNC)err_mmap },                 /* mmap */
  97         { &vnop_fsync_desc, (VOPFUNC)fifo_fsync },              /* fsync */
  98         { &vnop_remove_desc, (VOPFUNC)err_remove },             /* remove */
  99         { &vnop_link_desc, (VOPFUNC)err_link },                 /* link */
 100         { &vnop_rename_desc, (VOPFUNC)err_rename },             /* rename */
 101         { &vnop_mkdir_desc, (VOPFUNC)err_mkdir },               /* mkdir */
 102         { &vnop_rmdir_desc, (VOPFUNC)err_rmdir },               /* rmdir */
 103         { &vnop_symlink_desc, (VOPFUNC)err_symlink },           /* symlink */
 104         { &vnop_readdir_desc, (VOPFUNC)err_readdir },           /* readdir */
 105         { &vnop_readlink_desc, (VOPFUNC)err_readlink },         /* readlink */
 106         { &vnop_inactive_desc, (VOPFUNC)fifo_inactive },                /* inactive */
 107         { &vnop_reclaim_desc, (VOPFUNC)fifo_reclaim },          /* reclaim */
 108         { &vnop_strategy_desc, (VOPFUNC)err_strategy },         /* strategy */
 109         { &vnop_pathconf_desc, (VOPFUNC)fifo_pathconf },                /* pathconf */
 110         { &vnop_advlock_desc, (VOPFUNC)fifo_advlock },          /* advlock */
 111         { &vnop_bwrite_desc, (VOPFUNC)fifo_bwrite },            /* bwrite */
 112         { &vnop_pagein_desc, (VOPFUNC)err_pagein },             /* Pagein */
 113         { &vnop_pageout_desc, (VOPFUNC)err_pageout },           /* Pageout */
 114         { &vnop_copyfile_desc, (VOPFUNC)err_copyfile },         /* Copyfile */
 115         { &vnop_blktooff_desc, (VOPFUNC)err_blktooff },         /* blktooff */
 116         { &vnop_offtoblk_desc, (VOPFUNC)err_offtoblk },         /* offtoblk */
 117         { &vnop_blockmap_desc, (VOPFUNC)err_blockmap },                 /* blockmap */
 118         { (struct vnodeop_desc*)NULL, (int(*)())NULL }
 119 };
 120 struct vnodeopv_desc fifo_vnodeop_opv_desc =
 121         { &fifo_vnodeop_p, fifo_vnodeop_entries };
 122
 123 /*
 124  * Trivial lookup routine that always fails.
 125  */
 126 /* ARGSUSED */
 127 int
 128 fifo_lookup(ap)
 129         struct vnop_lookup_args /* {
 130                 struct vnode * a_dvp;
 131                 struct vnode ** a_vpp;
 132                 struct componentname * a_cnp;
 133                 vfs_context_t a_context;
 134         } */ *ap;
 135 {
 136
 137         *ap->a_vpp = NULL;
 138         return (ENOTDIR);
 139 }
 140
 141 /*
 142  * Open called to set up a new instance of a fifo or
 143  * to find an active instance of a fifo.
 144  */
 145 /* ARGSUSED */
 146 int
 147 fifo_open(ap)
 148         struct vnop_open_args /* {
 149                 struct vnode *a_vp;
 150                 int  a_mode;
 151                 vfs_context_t a_context;
 152         } */ *ap;
 153 {
 154         struct vnode *vp = ap->a_vp;
 155         struct fifoinfo *fip;
 156         struct socket *rso, *wso;
 157         int error;
 158
 159         vnode_lock(vp);
 160
 161 retry:
 162
 163         fip = vp->v_fifoinfo;
 164
 165         if (fip == (struct fifoinfo *)0)
 166                 panic("fifo_open with no fifoinfo");
 167
 168         if ((fip->fi_flags & FIFO_CREATED) == 0) {
 169                 if (fip->fi_flags & FIFO_INCREATE) {
 170                         fip->fi_flags |= FIFO_CREATEWAIT;
 171                         error = msleep(&fip->fi_flags, &vp->v_lock, PRIBIO | PCATCH, "fifocreatewait", 0);
 172                         if (error) {
 173                                 vnode_unlock(vp);
 174                                 return(error);
 175                         }
 176                         goto retry;
 177                 } else {
 178                         fip->fi_flags |= FIFO_INCREATE;
 179                         vnode_unlock(vp);
 180                         if ( (error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0)) ) {
 181                                 goto bad1;
 182                         }
 183                         fip->fi_readsock = rso;
 184
 185                         if ( (error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0)) ) {
 186                                 (void)soclose(rso);
 187                                 goto bad1;
 188                         }
 189                         fip->fi_writesock = wso;
 190
 191                         if ( (error = soconnect2(wso, rso)) ) {
 192                                 (void)soclose(wso);
 193                                 (void)soclose(rso);
 194                                 goto bad1;
 195                         }
 196                         fip->fi_readers = fip->fi_writers = 0;
 197
 198                 socket_lock(wso, 1);
 199                         wso->so_state |= SS_CANTRCVMORE;
 200                         wso->so_snd.sb_lowat = PIPE_BUF;
 201 #if 0
 202                         /* Because all the unp is protected by single mutex
 203                          * doing it in two step may actually cause problems
 204                          * as it opens up window between the drop and acquire
 205                          */
 206                 socket_unlock(wso, 1);
 207
 208                 socket_lock(rso, 1);
 209 #endif
 210                         rso->so_state |= SS_CANTSENDMORE;
 211                 socket_unlock(wso, 1);
 212
 213                         vnode_lock(vp);
 214                         fip->fi_flags |= FIFO_CREATED;
 215                         fip->fi_flags &= ~FIFO_INCREATE;
 216
 217                         if ((fip->fi_flags & FIFO_CREATEWAIT)) {
 218                                 fip->fi_flags &= ~FIFO_CREATEWAIT;
 219                                 wakeup(&fip->fi_flags);
 220                         }
 221                         /* vnode lock is held  to process further */
 222                 }
 223         }
 224
 225         /* vnode is locked at this point */
 226         /* fifo in created already */
 227         if (ap->a_mode & FREAD) {
 228                 fip->fi_readers++;
 229                 if (fip->fi_readers == 1) {
 230                         socket_lock(fip->fi_writesock, 1);
 231                         fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
 232                         socket_unlock(fip->fi_writesock, 1);
 233
 234                         if (fip->fi_writers > 0)
 235                                 wakeup((caddr_t)&fip->fi_writers);
 236                 }
 237         }
 238         if (ap->a_mode & FWRITE) {
 239                 fip->fi_writers++;
 240                 if (fip->fi_writers == 1) {
 241                         socket_lock(fip->fi_readsock, 1);
 242                         fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
 243                         socket_unlock(fip->fi_readsock, 1);
 244
 245                         if (fip->fi_readers > 0)
 246                                 wakeup((caddr_t)&fip->fi_readers);
 247                 }
 248         }
 249         if ((ap->a_mode & FREAD) && (ap->a_mode & O_NONBLOCK) == 0) {
 250                 if (fip->fi_writers == 0) {
 251                         error = msleep((caddr_t)&fip->fi_readers, &vp->v_lock,
 252                                         PCATCH | PSOCK, "fifoor", 0);
 253                         if (error)
 254                                 goto bad;
 255                         if (fip->fi_readers == 1) {
 256                                 if (fip->fi_writers > 0)
 257                                         wakeup((caddr_t)&fip->fi_writers);
 258                         }
 259                 }
 260         }
 261         if (ap->a_mode & FWRITE) {
 262                 if (ap->a_mode & O_NONBLOCK) {
 263                         if (fip->fi_readers == 0) {
 264                                         error = ENXIO;
 265                                         goto bad;
 266                         }
 267                 } else {
 268                         if (fip->fi_readers == 0) {
 269                                 error = msleep((caddr_t)&fip->fi_writers,&vp->v_lock,
 270                                                 PCATCH | PSOCK, "fifoow", 0);
 271                                 if (error)
 272                                         goto bad;
 273                                 if (fip->fi_writers == 1) {
 274                                         if (fip->fi_readers > 0)
 275                                                 wakeup((caddr_t)&fip->fi_readers);
 276                                 }
 277                         }
 278                 }
 279         }
 280
 281         vnode_unlock(vp);
 282         return (0);
 283 bad:
 284         fifo_close_internal(vp, ap->a_mode, ap->a_context, 1);
 285
 286         vnode_unlock(vp);
 287         return (error);
 288 bad1:
 289         vnode_lock(vp);
 290
 291         fip->fi_flags &= ~FIFO_INCREATE;
 292
 293         if ((fip->fi_flags & FIFO_CREATEWAIT)) {
 294                 fip->fi_flags &= ~FIFO_CREATEWAIT;
 295                 wakeup(&fip->fi_flags);
 296         }
 297         vnode_unlock(vp);
 298
 299         return (error);
 300 }
 301
 302 /*
 303  * Vnode op for read
 304  */
 305 int
 306 fifo_read(ap)
 307         struct vnop_read_args /* {
 308                 struct vnode *a_vp;
 309                 struct uio *a_uio;
 310                 int  a_ioflag;
 311                 vfs_context_t a_context;
 312         } */ *ap;
 313 {
 314         struct uio *uio = ap->a_uio;
 315         struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
 316         int error, startresid;
 317         int rflags;
 318
 319 #if DIAGNOSTIC
 320         if (uio->uio_rw != UIO_READ)
 321                 panic("fifo_read mode");
 322 #endif
 323         if (uio_resid(uio) == 0)
 324                 return (0);
 325
 326         rflags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0;
 327
 328         // LP64todo - fix this!
 329         startresid = uio_resid(uio);
 330
 331         /* fifo conformance - if we have a reader open on the fifo but no
 332          * writers then we need to make sure we do not block.  We do that by
 333          * checking the receive buffer and if empty set error to EWOULDBLOCK.
 334          * If error is set to EWOULDBLOCK we skip the call into soreceive
 335          */
 336         error = 0;
 337         if (ap->a_vp->v_fifoinfo->fi_writers < 1) {
 338                 socket_lock(rso, 1);
 339                 error = (rso->so_rcv.sb_cc == 0) ? EWOULDBLOCK : 0;
 340                 socket_unlock(rso, 1);
 341         }
 342
 343         /* skip soreceive to avoid blocking when we have no writers */
 344         if (error != EWOULDBLOCK) {
 345                 error = soreceive(rso, (struct sockaddr **)0, uio, (struct mbuf **)0,
 346                                                 (struct mbuf **)0, &rflags);
 347         }
 348         else {
 349                 /* clear EWOULDBLOCK and return EOF (zero) */
 350                 error = 0;
 351         }
 352         /*
 353          * Clear EOF indication after first such return.
 354          */
 355         if (uio_resid(uio) == startresid) {
 356                 socket_lock(rso, 1);
 357                 rso->so_state &= ~SS_CANTRCVMORE;
 358                 socket_unlock(rso, 1);
 359         }
 360         return (error);
 361 }
 362
 363 /*
 364  * Vnode op for write
 365  */
 366 int
 367 fifo_write(ap)
 368         struct vnop_write_args /* {
 369                 struct vnode *a_vp;
 370                 struct uio *a_uio;
 371                 int  a_ioflag;
 372                 vfs_context_t a_context;
 373         } */ *ap;
 374 {
 375         struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
 376         int error;
 377
 378 #if DIAGNOSTIC
 379         if (ap->a_uio->uio_rw != UIO_WRITE)
 380                 panic("fifo_write mode");
 381 #endif
 382         error = sosend(wso, (struct sockaddr *)0, ap->a_uio, 0,
 383                        (struct mbuf *)0, (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0);
 384
 385         return (error);
 386 }
 387
 388 /*
 389  * Device ioctl operation.
 390  */
 391 int
 392 fifo_ioctl(ap)
 393         struct vnop_ioctl_args /* {
 394                 struct vnode *a_vp;
 395                 int  a_command;
 396                 caddr_t  a_data;
 397                 int  a_fflag;
 398                 vfs_context_t a_context;
 399         } */ *ap;
 400 {
 401         struct proc *p = vfs_context_proc(ap->a_context);
 402         struct fileproc filetmp;
 403         struct fileglob filefg;
 404         int error;
 405
 406         if (ap->a_command == FIONBIO)
 407                 return (0);
 408         bzero(&filetmp, sizeof(struct fileproc));
 409         filetmp.f_fglob = &filefg;
 410         if (ap->a_fflag & FREAD) {
 411                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
 412                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, p);
 413                 if (error)
 414                         return (error);
 415         }
 416         if (ap->a_fflag & FWRITE) {
 417                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
 418                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, p);
 419                 if (error)
 420                         return (error);
 421         }
 422         return (0);
 423 }
 424
 425 int
 426 fifo_select(ap)
 427         struct vnop_select_args /* {
 428                 struct vnode *a_vp;
 429                 int  a_which;
 430                 int  a_fflags;
 431                 void * a_wql;
 432                 vfs_context_t a_context;
 433         } */ *ap;
 434 {
 435         struct proc *p = vfs_context_proc(ap->a_context);
 436         struct fileproc filetmp;
 437         struct fileglob filefg;
 438         int ready;
 439
 440         bzero(&filetmp, sizeof(struct fileproc));
 441         filetmp.f_fglob = &filefg;
 442         if (ap->a_which & FREAD) {
 443                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
 444                 ready = soo_select(&filetmp, ap->a_which, ap->a_wql, p);
 445                 if (ready)
 446                         return (ready);
 447         }
 448         if (ap->a_which & FWRITE) {
 449                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
 450                 ready = soo_select(&filetmp, ap->a_which, ap->a_wql, p);
 451                 if (ready)
 452                         return (ready);
 453         }
 454         return (0);
 455 }
 456
 457 int
 458 fifo_inactive(__unused struct vnop_inactive_args *ap)
 459 {
 460         return (0);
 461 }
 462
 463
 464 /*
 465  * Device close routine
 466  */
 467 int
 468 fifo_close(ap)
 469         struct vnop_close_args /* {
 470                 struct vnode *a_vp;
 471                 int  a_fflag;
 472                 vfs_context_t a_context;
 473         } */ *ap;
 474 {
 475         return fifo_close_internal(ap->a_vp, ap->a_fflag, ap->a_context, 0);
 476 }
 477
 478 int
 479 fifo_close_internal(vnode_t vp, int fflag, __unused vfs_context_t context, int locked)
 480 {
 481         register struct fifoinfo *fip = vp->v_fifoinfo;
 482         int error1, error2;
 483         struct socket *rso;
 484         struct socket *wso;
 485
 486         if (!locked)
 487                 vnode_lock(vp);
 488
 489         if ((fip->fi_flags & FIFO_CREATED) == 0) {
 490                 if (!locked)
 491                         vnode_unlock(vp);
 492                 return(0);
 493
 494         }
 495
 496         if (fflag & FREAD) {
 497                 fip->fi_readers--;
 498                 if (fip->fi_readers == 0){
 499                         socket_lock(fip->fi_writesock, 1);
 500                         socantsendmore(fip->fi_writesock);
 501                         socket_unlock(fip->fi_writesock, 1);
 502                 }
 503         }
 504
 505         if (fflag & FWRITE) {
 506                 fip->fi_writers--;
 507                 if (fip->fi_writers == 0) {
 508                         socket_lock(fip->fi_readsock, 1);
 509                         socantrcvmore(fip->fi_readsock);
 510                         socket_unlock(fip->fi_readsock, 1);
 511                 }
 512         }
 513 #if 0
 514         if (vnode_isinuse_locked(vp, 0, 1)) {
 515                 if (!locked)
 516                         vnode_unlock(vp);
 517                 return (0);
 518         }
 519 #endif
 520
 521         if (fip->fi_writers || fip->fi_readers) {
 522                 if (!locked)
 523                         vnode_unlock(vp);
 524                 return (0);
 525         }
 526
 527         wso = fip->fi_writesock;
 528         rso = fip->fi_readsock;
 529         fip->fi_readsock = 0;
 530         fip->fi_writesock = 0;
 531         fip->fi_flags &= ~FIFO_CREATED;
 532         if (!locked)
 533                 vnode_unlock(vp);
 534         error1 = soclose(rso);
 535         error2 = soclose(wso);
 536
 537         if (error1)
 538                 return (error1);
 539         return (error2);
 540 }
 541
 542
 543 /*
 544  * Print out internal contents of a fifo vnode.
 545  */
 546 void
 547 fifo_printinfo(vp)
 548         struct vnode *vp;
 549 {
 550         register struct fifoinfo *fip = vp->v_fifoinfo;
 551
 552         printf(", fifo with %d readers and %d writers",
 553                 fip->fi_readers, fip->fi_writers);
 554 }
 555
 556 /*
 557  * Return POSIX pathconf information applicable to fifo's.
 558  */
 559 int
 560 fifo_pathconf(ap)
 561         struct vnop_pathconf_args /* {
 562                 struct vnode *a_vp;
 563                 int a_name;
 564                 int *a_retval;
 565                 vfs_context_t a_context;
 566         } */ *ap;
 567 {
 568
 569         switch (ap->a_name) {
 570         case _PC_LINK_MAX:
 571                 *ap->a_retval = LINK_MAX;
 572                 return (0);
 573         case _PC_PIPE_BUF:
 574                 *ap->a_retval = PIPE_BUF;
 575                 return (0);
 576         case _PC_CHOWN_RESTRICTED:
 577                 *ap->a_retval = 1;
 578                 return (0);
 579         default:
 580                 return (EINVAL);
 581         }
 582         /* NOTREACHED */
 583 }
 584
 585 /*
 586  * Fifo failed operation
 587  */
 588 int
 589 fifo_ebadf(__unused void *dummy)
 590 {
 591
 592         return (EBADF);
 593 }
 594
 595 /*
 596  * Fifo advisory byte-level locks.
 597  */
 598 int
 599 fifo_advlock(__unused struct vnop_advlock_args *ap)
 600 {
 601
 602         return (ENOTSUP);
 603 }
 604