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 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)fifo_vnops.c 8.10 (Berkeley) 5/27/95 30 * $FreeBSD$ 31 */ 32 33 #include <sys/param.h> 34 #include <sys/event.h> 35 #include <sys/filio.h> 36 #include <sys/fcntl.h> 37 #include <sys/file.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.h> 41 #include <sys/malloc.h> 42 #include <sys/poll.h> 43 #include <sys/proc.h> /* XXXKSE */ 44 #include <sys/signalvar.h> 45 #include <sys/socket.h> 46 #include <sys/socketvar.h> 47 #include <sys/sx.h> 48 #include <sys/systm.h> 49 #include <sys/un.h> 50 #include <sys/unistd.h> 51 #include <sys/vnode.h> 52 #include <fs/fifofs/fifo.h> 53 54 /* 55 * This structure is associated with the FIFO vnode and stores 56 * the state associated with the FIFO. 57 */ 58 struct fifoinfo { 59 struct socket *fi_readsock; 60 struct socket *fi_writesock; 61 long fi_readers; 62 long fi_writers; 63 }; 64 65 static int fifo_print(struct vop_print_args *); 66 static int fifo_lookup(struct vop_lookup_args *); 67 static int fifo_open(struct vop_open_args *); 68 static int fifo_close(struct vop_close_args *); 69 static int fifo_read(struct vop_read_args *); 70 static int fifo_write(struct vop_write_args *); 71 static int fifo_ioctl(struct vop_ioctl_args *); 72 static int fifo_poll(struct vop_poll_args *); 73 static int fifo_kqfilter(struct vop_kqfilter_args *); 74 static int fifo_pathconf(struct vop_pathconf_args *); 75 static int fifo_advlock(struct vop_advlock_args *); 76 77 static void filt_fifordetach(struct knote *kn); 78 static int filt_fiforead(struct knote *kn, long hint); 79 static void filt_fifowdetach(struct knote *kn); 80 static int filt_fifowrite(struct knote *kn, long hint); 81 82 static struct filterops fiforead_filtops = 83 { 1, NULL, filt_fifordetach, filt_fiforead }; 84 static struct filterops fifowrite_filtops = 85 { 1, NULL, filt_fifowdetach, filt_fifowrite }; 86 87 vop_t **fifo_vnodeop_p; 88 static struct vnodeopv_entry_desc fifo_vnodeop_entries[] = { 89 { &vop_default_desc, (vop_t *) vop_defaultop }, 90 { &vop_access_desc, (vop_t *) vop_ebadf }, 91 { &vop_advlock_desc, (vop_t *) fifo_advlock }, 92 { &vop_close_desc, (vop_t *) fifo_close }, 93 { &vop_create_desc, (vop_t *) vop_panic }, 94 { &vop_getattr_desc, (vop_t *) vop_ebadf }, 95 { &vop_getwritemount_desc, (vop_t *) vop_stdgetwritemount }, 96 { &vop_ioctl_desc, (vop_t *) fifo_ioctl }, 97 { &vop_kqfilter_desc, (vop_t *) fifo_kqfilter }, 98 { &vop_lease_desc, (vop_t *) vop_null }, 99 { &vop_link_desc, (vop_t *) vop_panic }, 100 { &vop_lookup_desc, (vop_t *) fifo_lookup }, 101 { &vop_mkdir_desc, (vop_t *) vop_panic }, 102 { &vop_mknod_desc, (vop_t *) vop_panic }, 103 { &vop_open_desc, (vop_t *) fifo_open }, 104 { &vop_pathconf_desc, (vop_t *) fifo_pathconf }, 105 { &vop_poll_desc, (vop_t *) fifo_poll }, 106 { &vop_print_desc, (vop_t *) fifo_print }, 107 { &vop_read_desc, (vop_t *) fifo_read }, 108 { &vop_readdir_desc, (vop_t *) vop_panic }, 109 { &vop_readlink_desc, (vop_t *) vop_panic }, 110 { &vop_reallocblks_desc, (vop_t *) vop_panic }, 111 { &vop_reclaim_desc, (vop_t *) vop_null }, 112 { &vop_remove_desc, (vop_t *) vop_panic }, 113 { &vop_rename_desc, (vop_t *) vop_panic }, 114 { &vop_rmdir_desc, (vop_t *) vop_panic }, 115 { &vop_setattr_desc, (vop_t *) vop_ebadf }, 116 { &vop_symlink_desc, (vop_t *) vop_panic }, 117 { &vop_write_desc, (vop_t *) fifo_write }, 118 { NULL, NULL } 119 }; 120 static struct vnodeopv_desc fifo_vnodeop_opv_desc = 121 { &fifo_vnodeop_p, fifo_vnodeop_entries }; 122 123 VNODEOP_SET(fifo_vnodeop_opv_desc); 124 125 struct mtx fifo_mtx; 126 MTX_SYSINIT(fifo, &fifo_mtx, "fifo mutex", MTX_DEF); 127 128 int 129 fifo_vnoperate(ap) 130 struct vop_generic_args /* { 131 struct vnodeop_desc *a_desc; 132 <other random data follows, presumably> 133 } */ *ap; 134 { 135 return (VOCALL(fifo_vnodeop_p, ap->a_desc->vdesc_offset, ap)); 136 } 137 138 /* 139 * Trivial lookup routine that always fails. 140 */ 141 /* ARGSUSED */ 142 static int 143 fifo_lookup(ap) 144 struct vop_lookup_args /* { 145 struct vnode * a_dvp; 146 struct vnode ** a_vpp; 147 struct componentname * a_cnp; 148 } */ *ap; 149 { 150 151 *ap->a_vpp = NULL; 152 return (ENOTDIR); 153 } 154 155 /* 156 * Dispose of fifo resources. 157 */ 158 static void 159 fifo_cleanup(struct vnode *vp) 160 { 161 struct fifoinfo *fip = vp->v_fifoinfo; 162 163 ASSERT_VOP_LOCKED(vp, "fifo_cleanup"); 164 if (fip->fi_readers == 0 && fip->fi_writers == 0) { 165 vp->v_fifoinfo = NULL; 166 (void)soclose(fip->fi_readsock); 167 (void)soclose(fip->fi_writesock); 168 FREE(fip, M_VNODE); 169 } 170 } 171 172 /* 173 * Open called to set up a new instance of a fifo or 174 * to find an active instance of a fifo. 175 */ 176 /* ARGSUSED */ 177 static int 178 fifo_open(ap) 179 struct vop_open_args /* { 180 struct vnode *a_vp; 181 int a_mode; 182 struct ucred *a_cred; 183 struct thread *a_td; 184 } */ *ap; 185 { 186 struct vnode *vp = ap->a_vp; 187 struct fifoinfo *fip; 188 struct thread *td = ap->a_td; 189 struct ucred *cred = ap->a_cred; 190 struct socket *rso, *wso; 191 int error; 192 193 if ((fip = vp->v_fifoinfo) == NULL) { 194 MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK); 195 error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0, cred, td); 196 if (error) 197 goto fail1; 198 fip->fi_readsock = rso; 199 error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0, cred, td); 200 if (error) 201 goto fail2; 202 fip->fi_writesock = wso; 203 error = uipc_connect2(wso, rso); 204 if (error) { 205 (void)soclose(wso); 206 fail2: 207 (void)soclose(rso); 208 fail1: 209 free(fip, M_VNODE); 210 return (error); 211 } 212 fip->fi_readers = fip->fi_writers = 0; 213 wso->so_snd.sb_lowat = PIPE_BUF; 214 SOCKBUF_LOCK(&rso->so_rcv); 215 rso->so_rcv.sb_state |= SBS_CANTRCVMORE; 216 SOCKBUF_UNLOCK(&rso->so_rcv); 217 vp->v_fifoinfo = fip; 218 } 219 220 /* 221 * General access to fi_readers and fi_writers is protected using 222 * the vnode lock. 223 * 224 * Protect the increment of fi_readers and fi_writers and the 225 * associated calls to wakeup() with the fifo mutex in addition 226 * to the vnode lock. This allows the vnode lock to be dropped 227 * for the msleep() calls below, and using the fifo mutex with 228 * msleep() prevents the wakeup from being missed. 229 */ 230 mtx_lock(&fifo_mtx); 231 if (ap->a_mode & FREAD) { 232 fip->fi_readers++; 233 if (fip->fi_readers == 1) { 234 SOCKBUF_LOCK(&fip->fi_writesock->so_snd); 235 fip->fi_writesock->so_snd.sb_state &= ~SBS_CANTSENDMORE; 236 SOCKBUF_UNLOCK(&fip->fi_writesock->so_snd); 237 if (fip->fi_writers > 0) { 238 wakeup(&fip->fi_writers); 239 sowwakeup(fip->fi_writesock); 240 } 241 } 242 } 243 if (ap->a_mode & FWRITE) { 244 if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) { 245 mtx_unlock(&fifo_mtx); 246 return (ENXIO); 247 } 248 fip->fi_writers++; 249 if (fip->fi_writers == 1) { 250 SOCKBUF_LOCK(&fip->fi_writesock->so_rcv); 251 fip->fi_readsock->so_rcv.sb_state &= ~SBS_CANTRCVMORE; 252 SOCKBUF_UNLOCK(&fip->fi_writesock->so_rcv); 253 if (fip->fi_readers > 0) { 254 wakeup(&fip->fi_readers); 255 sorwakeup(fip->fi_writesock); 256 } 257 } 258 } 259 if ((ap->a_mode & O_NONBLOCK) == 0) { 260 if ((ap->a_mode & FREAD) && fip->fi_writers == 0) { 261 VOP_UNLOCK(vp, 0, td); 262 error = msleep(&fip->fi_readers, &fifo_mtx, 263 PDROP | PCATCH | PSOCK, "fifoor", 0); 264 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 265 if (error) { 266 fip->fi_readers--; 267 if (fip->fi_readers == 0) { 268 socantsendmore(fip->fi_writesock); 269 fifo_cleanup(vp); 270 } 271 return (error); 272 } 273 mtx_lock(&fifo_mtx); 274 /* 275 * We must have got woken up because we had a writer. 276 * That (and not still having one) is the condition 277 * that we must wait for. 278 */ 279 } 280 if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) { 281 VOP_UNLOCK(vp, 0, td); 282 error = msleep(&fip->fi_writers, &fifo_mtx, 283 PDROP | PCATCH | PSOCK, "fifoow", 0); 284 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 285 if (error) { 286 fip->fi_writers--; 287 if (fip->fi_writers == 0) { 288 socantrcvmore(fip->fi_readsock); 289 fifo_cleanup(vp); 290 } 291 return (error); 292 } 293 /* 294 * We must have got woken up because we had 295 * a reader. That (and not still having one) 296 * is the condition that we must wait for. 297 */ 298 return (0); 299 } 300 } 301 mtx_unlock(&fifo_mtx); 302 return (0); 303 } 304 305 /* 306 * Vnode op for read 307 */ 308 /* ARGSUSED */ 309 static int 310 fifo_read(ap) 311 struct vop_read_args /* { 312 struct vnode *a_vp; 313 struct uio *a_uio; 314 int a_ioflag; 315 struct ucred *a_cred; 316 } */ *ap; 317 { 318 struct uio *uio = ap->a_uio; 319 struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock; 320 struct thread *td = uio->uio_td; 321 int error, flags; 322 323 #ifdef DIAGNOSTIC 324 if (uio->uio_rw != UIO_READ) 325 panic("fifo_read mode"); 326 #endif 327 if (uio->uio_resid == 0) 328 return (0); 329 VOP_UNLOCK(ap->a_vp, 0, td); 330 flags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0; 331 error = soreceive(rso, (struct sockaddr **)0, uio, (struct mbuf **)0, 332 (struct mbuf **)0, &flags); 333 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, td); 334 return (error); 335 } 336 337 /* 338 * Vnode op for write 339 */ 340 /* ARGSUSED */ 341 static int 342 fifo_write(ap) 343 struct vop_write_args /* { 344 struct vnode *a_vp; 345 struct uio *a_uio; 346 int a_ioflag; 347 struct ucred *a_cred; 348 } */ *ap; 349 { 350 struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock; 351 struct thread *td = ap->a_uio->uio_td; 352 int error, flags; 353 354 #ifdef DIAGNOSTIC 355 if (ap->a_uio->uio_rw != UIO_WRITE) 356 panic("fifo_write mode"); 357 #endif 358 VOP_UNLOCK(ap->a_vp, 0, td); 359 flags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0; 360 error = sosend(wso, (struct sockaddr *)0, ap->a_uio, 0, 361 (struct mbuf *)0, flags, td); 362 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, td); 363 return (error); 364 } 365 366 /* 367 * Device ioctl operation. 368 */ 369 /* ARGSUSED */ 370 static int 371 fifo_ioctl(ap) 372 struct vop_ioctl_args /* { 373 struct vnode *a_vp; 374 u_long a_command; 375 caddr_t a_data; 376 int a_fflag; 377 struct ucred *a_cred; 378 struct thread *a_td; 379 } */ *ap; 380 { 381 struct file filetmp; /* Local, so need not be locked. */ 382 int error; 383 384 if (ap->a_command == FIONBIO) 385 return (0); 386 if (ap->a_fflag & FREAD) { 387 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 388 filetmp.f_cred = ap->a_cred; 389 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, 390 ap->a_td->td_ucred, ap->a_td); 391 if (error) 392 return (error); 393 } 394 if (ap->a_fflag & FWRITE) { 395 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 396 filetmp.f_cred = ap->a_cred; 397 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, 398 ap->a_td->td_ucred, ap->a_td); 399 if (error) 400 return (error); 401 } 402 return (0); 403 } 404 405 /* ARGSUSED */ 406 static int 407 fifo_kqfilter(ap) 408 struct vop_kqfilter_args /* { 409 struct vnode *a_vp; 410 struct knote *a_kn; 411 } */ *ap; 412 { 413 struct fifoinfo *fi = ap->a_vp->v_fifoinfo; 414 struct socket *so; 415 struct sockbuf *sb; 416 417 switch (ap->a_kn->kn_filter) { 418 case EVFILT_READ: 419 ap->a_kn->kn_fop = &fiforead_filtops; 420 so = fi->fi_readsock; 421 sb = &so->so_rcv; 422 break; 423 case EVFILT_WRITE: 424 ap->a_kn->kn_fop = &fifowrite_filtops; 425 so = fi->fi_writesock; 426 sb = &so->so_snd; 427 break; 428 default: 429 return (1); 430 } 431 432 ap->a_kn->kn_hook = (caddr_t)so; 433 434 SOCKBUF_LOCK(sb); 435 SLIST_INSERT_HEAD(&sb->sb_sel.si_note, ap->a_kn, kn_selnext); 436 sb->sb_flags |= SB_KNOTE; 437 SOCKBUF_UNLOCK(sb); 438 439 return (0); 440 } 441 442 static void 443 filt_fifordetach(struct knote *kn) 444 { 445 struct socket *so = (struct socket *)kn->kn_hook; 446 447 SOCKBUF_LOCK(&so->so_rcv); 448 SLIST_REMOVE(&so->so_rcv.sb_sel.si_note, kn, knote, kn_selnext); 449 if (SLIST_EMPTY(&so->so_rcv.sb_sel.si_note)) 450 so->so_rcv.sb_flags &= ~SB_KNOTE; 451 SOCKBUF_UNLOCK(&so->so_rcv); 452 } 453 454 static int 455 filt_fiforead(struct knote *kn, long hint) 456 { 457 struct socket *so = (struct socket *)kn->kn_hook; 458 int need_lock, result; 459 460 need_lock = !SOCKBUF_OWNED(&so->so_rcv); 461 if (need_lock) 462 SOCKBUF_LOCK(&so->so_rcv); 463 kn->kn_data = so->so_rcv.sb_cc; 464 if (so->so_rcv.sb_state & SBS_CANTRCVMORE) { 465 kn->kn_flags |= EV_EOF; 466 result = 1; 467 } else { 468 kn->kn_flags &= ~EV_EOF; 469 result = (kn->kn_data > 0); 470 } 471 if (need_lock) 472 SOCKBUF_UNLOCK(&so->so_rcv); 473 return (result); 474 } 475 476 static void 477 filt_fifowdetach(struct knote *kn) 478 { 479 struct socket *so = (struct socket *)kn->kn_hook; 480 481 SOCKBUF_LOCK(&so->so_snd); 482 SLIST_REMOVE(&so->so_snd.sb_sel.si_note, kn, knote, kn_selnext); 483 if (SLIST_EMPTY(&so->so_snd.sb_sel.si_note)) 484 so->so_snd.sb_flags &= ~SB_KNOTE; 485 SOCKBUF_UNLOCK(&so->so_snd); 486 } 487 488 static int 489 filt_fifowrite(struct knote *kn, long hint) 490 { 491 struct socket *so = (struct socket *)kn->kn_hook; 492 int need_lock, result; 493 494 need_lock = !SOCKBUF_OWNED(&so->so_snd); 495 if (need_lock) 496 SOCKBUF_LOCK(&so->so_snd); 497 kn->kn_data = sbspace(&so->so_snd); 498 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 499 kn->kn_flags |= EV_EOF; 500 result = 1; 501 } else { 502 kn->kn_flags &= ~EV_EOF; 503 result = (kn->kn_data >= so->so_snd.sb_lowat); 504 } 505 if (need_lock) 506 SOCKBUF_UNLOCK(&so->so_snd); 507 return (result); 508 } 509 510 /* ARGSUSED */ 511 static int 512 fifo_poll(ap) 513 struct vop_poll_args /* { 514 struct vnode *a_vp; 515 int a_events; 516 struct ucred *a_cred; 517 struct thread *a_td; 518 } */ *ap; 519 { 520 struct file filetmp; 521 int events, revents = 0; 522 523 events = ap->a_events & 524 (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND); 525 if (events) { 526 /* 527 * If POLLIN or POLLRDNORM is requested and POLLINIGNEOF is 528 * not, then convert the first two to the last one. This 529 * tells the socket poll function to ignore EOF so that we 530 * block if there is no writer (and no data). Callers can 531 * set POLLINIGNEOF to get non-blocking behavior. 532 */ 533 if (events & (POLLIN | POLLRDNORM) && 534 !(events & POLLINIGNEOF)) { 535 events &= ~(POLLIN | POLLRDNORM); 536 events |= POLLINIGNEOF; 537 } 538 539 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 540 filetmp.f_cred = ap->a_cred; 541 if (filetmp.f_data) 542 revents |= soo_poll(&filetmp, events, 543 ap->a_td->td_ucred, ap->a_td); 544 545 /* Reverse the above conversion. */ 546 if ((revents & POLLINIGNEOF) && 547 !(ap->a_events & POLLINIGNEOF)) { 548 revents |= (ap->a_events & (POLLIN | POLLRDNORM)); 549 revents &= ~POLLINIGNEOF; 550 } 551 } 552 events = ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND); 553 if (events) { 554 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 555 filetmp.f_cred = ap->a_cred; 556 if (filetmp.f_data) { 557 revents |= soo_poll(&filetmp, events, 558 ap->a_td->td_ucred, ap->a_td); 559 } 560 } 561 return (revents); 562 } 563 564 /* 565 * Device close routine 566 */ 567 /* ARGSUSED */ 568 static int 569 fifo_close(ap) 570 struct vop_close_args /* { 571 struct vnode *a_vp; 572 int a_fflag; 573 struct ucred *a_cred; 574 struct thread *a_td; 575 } */ *ap; 576 { 577 struct vnode *vp = ap->a_vp; 578 struct thread *td = ap->a_td; 579 struct fifoinfo *fip = vp->v_fifoinfo; 580 581 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 582 583 if (ap->a_fflag & FREAD) { 584 fip->fi_readers--; 585 if (fip->fi_readers == 0) 586 socantsendmore(fip->fi_writesock); 587 } 588 if (ap->a_fflag & FWRITE) { 589 fip->fi_writers--; 590 if (fip->fi_writers == 0) 591 socantrcvmore(fip->fi_readsock); 592 } 593 fifo_cleanup(vp); 594 VOP_UNLOCK(vp, 0, td); 595 return (0); 596 } 597 598 /* 599 * Print out internal contents of a fifo vnode. 600 */ 601 int 602 fifo_printinfo(vp) 603 struct vnode *vp; 604 { 605 register struct fifoinfo *fip = vp->v_fifoinfo; 606 607 printf(", fifo with %ld readers and %ld writers", 608 fip->fi_readers, fip->fi_writers); 609 return (0); 610 } 611 612 /* 613 * Print out the contents of a fifo vnode. 614 */ 615 static int 616 fifo_print(ap) 617 struct vop_print_args /* { 618 struct vnode *a_vp; 619 } */ *ap; 620 { 621 fifo_printinfo(ap->a_vp); 622 printf("\n"); 623 return (0); 624 } 625 626 /* 627 * Return POSIX pathconf information applicable to fifo's. 628 */ 629 static int 630 fifo_pathconf(ap) 631 struct vop_pathconf_args /* { 632 struct vnode *a_vp; 633 int a_name; 634 int *a_retval; 635 } */ *ap; 636 { 637 638 switch (ap->a_name) { 639 case _PC_LINK_MAX: 640 *ap->a_retval = LINK_MAX; 641 return (0); 642 case _PC_PIPE_BUF: 643 *ap->a_retval = PIPE_BUF; 644 return (0); 645 case _PC_CHOWN_RESTRICTED: 646 *ap->a_retval = 1; 647 return (0); 648 default: 649 return (EINVAL); 650 } 651 /* NOTREACHED */ 652 } 653 654 /* 655 * Fifo advisory byte-level locks. 656 */ 657 /* ARGSUSED */ 658 static int 659 fifo_advlock(ap) 660 struct vop_advlock_args /* { 661 struct vnode *a_vp; 662 caddr_t a_id; 663 int a_op; 664 struct flock *a_fl; 665 int a_flags; 666 } */ *ap; 667 { 668 669 return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL); 670 } 671