Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/fifofs/fifo_vnops.c
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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: src/sys/fs/fifofs/fifo_vnops.c,v 1.101.2.10 2005/09/28 06:56:14 rwatson Exp $ 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 ASSERT_VOP_LOCKED(vp, "fifo_open"); 194 if ((fip = vp->v_fifoinfo) == NULL) { 195 MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK); 196 error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0, cred, td); 197 if (error) 198 goto fail1; 199 fip->fi_readsock = rso; 200 error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0, cred, td); 201 if (error) 202 goto fail2; 203 fip->fi_writesock = wso; 204 error = soconnect2(wso, rso); 205 if (error) { 206 (void)soclose(wso); 207 fail2: 208 (void)soclose(rso); 209 fail1: 210 free(fip, M_VNODE); 211 return (error); 212 } 213 fip->fi_readers = fip->fi_writers = 0; 214 wso->so_snd.sb_lowat = PIPE_BUF; 215 SOCKBUF_LOCK(&rso->so_rcv); 216 rso->so_rcv.sb_state |= SBS_CANTRCVMORE; 217 SOCKBUF_UNLOCK(&rso->so_rcv); 218 KASSERT(vp->v_fifoinfo == NULL, 219 ("fifo_open: v_fifoinfo race")); 220 vp->v_fifoinfo = fip; 221 } 222 223 /* 224 * General access to fi_readers and fi_writers is protected using 225 * the vnode lock. 226 * 227 * Protect the increment of fi_readers and fi_writers and the 228 * associated calls to wakeup() with the fifo mutex in addition 229 * to the vnode lock. This allows the vnode lock to be dropped 230 * for the msleep() calls below, and using the fifo mutex with 231 * msleep() prevents the wakeup from being missed. 232 */ 233 mtx_lock(&fifo_mtx); 234 if (ap->a_mode & FREAD) { 235 fip->fi_readers++; 236 if (fip->fi_readers == 1) { 237 SOCKBUF_LOCK(&fip->fi_writesock->so_snd); 238 fip->fi_writesock->so_snd.sb_state &= ~SBS_CANTSENDMORE; 239 SOCKBUF_UNLOCK(&fip->fi_writesock->so_snd); 240 if (fip->fi_writers > 0) { 241 wakeup(&fip->fi_writers); 242 sowwakeup(fip->fi_writesock); 243 } 244 } 245 } 246 if (ap->a_mode & FWRITE) { 247 if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) { 248 mtx_unlock(&fifo_mtx); 249 return (ENXIO); 250 } 251 fip->fi_writers++; 252 if (fip->fi_writers == 1) { 253 SOCKBUF_LOCK(&fip->fi_readsock->so_rcv); 254 fip->fi_readsock->so_rcv.sb_state &= ~SBS_CANTRCVMORE; 255 SOCKBUF_UNLOCK(&fip->fi_readsock->so_rcv); 256 if (fip->fi_readers > 0) { 257 wakeup(&fip->fi_readers); 258 sorwakeup(fip->fi_readsock); 259 } 260 } 261 } 262 if ((ap->a_mode & O_NONBLOCK) == 0) { 263 if ((ap->a_mode & FREAD) && fip->fi_writers == 0) { 264 VOP_UNLOCK(vp, 0, td); 265 error = msleep(&fip->fi_readers, &fifo_mtx, 266 PDROP | PCATCH | PSOCK, "fifoor", 0); 267 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 268 if (error) { 269 fip->fi_readers--; 270 if (fip->fi_readers == 0) { 271 socantsendmore(fip->fi_writesock); 272 fifo_cleanup(vp); 273 } 274 return (error); 275 } 276 mtx_lock(&fifo_mtx); 277 /* 278 * We must have got woken up because we had a writer. 279 * That (and not still having one) is the condition 280 * that we must wait for. 281 */ 282 } 283 if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) { 284 VOP_UNLOCK(vp, 0, td); 285 error = msleep(&fip->fi_writers, &fifo_mtx, 286 PDROP | PCATCH | PSOCK, "fifoow", 0); 287 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 288 if (error) { 289 fip->fi_writers--; 290 if (fip->fi_writers == 0) { 291 socantrcvmore(fip->fi_readsock); 292 fifo_cleanup(vp); 293 } 294 return (error); 295 } 296 /* 297 * We must have got woken up because we had 298 * a reader. That (and not still having one) 299 * is the condition that we must wait for. 300 */ 301 return (0); 302 } 303 } 304 mtx_unlock(&fifo_mtx); 305 return (0); 306 } 307 308 /* 309 * Vnode op for read 310 */ 311 /* ARGSUSED */ 312 static int 313 fifo_read(ap) 314 struct vop_read_args /* { 315 struct vnode *a_vp; 316 struct uio *a_uio; 317 int a_ioflag; 318 struct ucred *a_cred; 319 } */ *ap; 320 { 321 struct uio *uio = ap->a_uio; 322 struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock; 323 struct thread *td = uio->uio_td; 324 int error, flags; 325 326 #ifdef DIAGNOSTIC 327 if (uio->uio_rw != UIO_READ) 328 panic("fifo_read mode"); 329 #endif 330 if (uio->uio_resid == 0) 331 return (0); 332 VOP_UNLOCK(ap->a_vp, 0, td); 333 flags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0; 334 error = soreceive(rso, (struct sockaddr **)0, uio, (struct mbuf **)0, 335 (struct mbuf **)0, &flags); 336 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, td); 337 return (error); 338 } 339 340 /* 341 * Vnode op for write 342 */ 343 /* ARGSUSED */ 344 static int 345 fifo_write(ap) 346 struct vop_write_args /* { 347 struct vnode *a_vp; 348 struct uio *a_uio; 349 int a_ioflag; 350 struct ucred *a_cred; 351 } */ *ap; 352 { 353 struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock; 354 struct thread *td = ap->a_uio->uio_td; 355 int error, flags; 356 357 #ifdef DIAGNOSTIC 358 if (ap->a_uio->uio_rw != UIO_WRITE) 359 panic("fifo_write mode"); 360 #endif 361 VOP_UNLOCK(ap->a_vp, 0, td); 362 flags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0; 363 error = sosend(wso, (struct sockaddr *)0, ap->a_uio, 0, 364 (struct mbuf *)0, flags, td); 365 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, td); 366 return (error); 367 } 368 369 /* 370 * Device ioctl operation. 371 */ 372 /* ARGSUSED */ 373 static int 374 fifo_ioctl(ap) 375 struct vop_ioctl_args /* { 376 struct vnode *a_vp; 377 u_long a_command; 378 caddr_t a_data; 379 int a_fflag; 380 struct ucred *a_cred; 381 struct thread *a_td; 382 } */ *ap; 383 { 384 struct file filetmp; /* Local, so need not be locked. */ 385 int error; 386 387 if (ap->a_command == FIONBIO) 388 return (0); 389 if (ap->a_fflag & FREAD) { 390 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 391 filetmp.f_cred = ap->a_cred; 392 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, 393 ap->a_td->td_ucred, ap->a_td); 394 if (error) 395 return (error); 396 } 397 if (ap->a_fflag & FWRITE) { 398 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 399 filetmp.f_cred = ap->a_cred; 400 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, 401 ap->a_td->td_ucred, ap->a_td); 402 if (error) 403 return (error); 404 } 405 return (0); 406 } 407 408 /* ARGSUSED */ 409 static int 410 fifo_kqfilter(ap) 411 struct vop_kqfilter_args /* { 412 struct vnode *a_vp; 413 struct knote *a_kn; 414 } */ *ap; 415 { 416 struct fifoinfo *fi = ap->a_vp->v_fifoinfo; 417 struct socket *so; 418 struct sockbuf *sb; 419 420 switch (ap->a_kn->kn_filter) { 421 case EVFILT_READ: 422 ap->a_kn->kn_fop = &fiforead_filtops; 423 so = fi->fi_readsock; 424 sb = &so->so_rcv; 425 break; 426 case EVFILT_WRITE: 427 ap->a_kn->kn_fop = &fifowrite_filtops; 428 so = fi->fi_writesock; 429 sb = &so->so_snd; 430 break; 431 default: 432 return (EINVAL); 433 } 434 435 ap->a_kn->kn_hook = (caddr_t)so; 436 437 SOCKBUF_LOCK(sb); 438 knlist_add(&sb->sb_sel.si_note, ap->a_kn, 1); 439 sb->sb_flags |= SB_KNOTE; 440 SOCKBUF_UNLOCK(sb); 441 442 return (0); 443 } 444 445 static void 446 filt_fifordetach(struct knote *kn) 447 { 448 struct socket *so = (struct socket *)kn->kn_hook; 449 450 SOCKBUF_LOCK(&so->so_rcv); 451 knlist_remove(&so->so_rcv.sb_sel.si_note, kn, 1); 452 if (knlist_empty(&so->so_rcv.sb_sel.si_note)) 453 so->so_rcv.sb_flags &= ~SB_KNOTE; 454 SOCKBUF_UNLOCK(&so->so_rcv); 455 } 456 457 static int 458 filt_fiforead(struct knote *kn, long hint) 459 { 460 struct socket *so = (struct socket *)kn->kn_hook; 461 462 SOCKBUF_LOCK_ASSERT(&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 return (1); 467 } else { 468 kn->kn_flags &= ~EV_EOF; 469 return (kn->kn_data > 0); 470 } 471 } 472 473 static void 474 filt_fifowdetach(struct knote *kn) 475 { 476 struct socket *so = (struct socket *)kn->kn_hook; 477 478 SOCKBUF_LOCK(&so->so_snd); 479 knlist_remove(&so->so_snd.sb_sel.si_note, kn, 1); 480 if (knlist_empty(&so->so_snd.sb_sel.si_note)) 481 so->so_snd.sb_flags &= ~SB_KNOTE; 482 SOCKBUF_UNLOCK(&so->so_snd); 483 } 484 485 static int 486 filt_fifowrite(struct knote *kn, long hint) 487 { 488 struct socket *so = (struct socket *)kn->kn_hook; 489 490 SOCKBUF_LOCK_ASSERT(&so->so_snd); 491 kn->kn_data = sbspace(&so->so_snd); 492 if (so->so_snd.sb_state & SBS_CANTSENDMORE) { 493 kn->kn_flags |= EV_EOF; 494 return (1); 495 } else { 496 kn->kn_flags &= ~EV_EOF; 497 return (kn->kn_data >= so->so_snd.sb_lowat); 498 } 499 } 500 501 /* ARGSUSED */ 502 static int 503 fifo_poll(ap) 504 struct vop_poll_args /* { 505 struct vnode *a_vp; 506 int a_events; 507 struct ucred *a_cred; 508 struct thread *a_td; 509 } */ *ap; 510 { 511 struct file filetmp; 512 int events, revents = 0; 513 514 events = ap->a_events & 515 (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND); 516 if (events) { 517 /* 518 * If POLLIN or POLLRDNORM is requested and POLLINIGNEOF is 519 * not, then convert the first two to the last one. This 520 * tells the socket poll function to ignore EOF so that we 521 * block if there is no writer (and no data). Callers can 522 * set POLLINIGNEOF to get non-blocking behavior. 523 */ 524 if (events & (POLLIN | POLLRDNORM) && 525 !(events & POLLINIGNEOF)) { 526 events &= ~(POLLIN | POLLRDNORM); 527 events |= POLLINIGNEOF; 528 } 529 530 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 531 filetmp.f_cred = ap->a_cred; 532 revents |= soo_poll(&filetmp, events, ap->a_td->td_ucred, 533 ap->a_td); 534 535 /* Reverse the above conversion. */ 536 if ((revents & POLLINIGNEOF) && 537 !(ap->a_events & POLLINIGNEOF)) { 538 revents |= (ap->a_events & (POLLIN | POLLRDNORM)); 539 revents &= ~POLLINIGNEOF; 540 } 541 } 542 events = ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND); 543 if (events) { 544 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 545 filetmp.f_cred = ap->a_cred; 546 revents |= soo_poll(&filetmp, events, ap->a_td->td_ucred, 547 ap->a_td); 548 } 549 return (revents); 550 } 551 552 /* 553 * Device close routine 554 */ 555 /* ARGSUSED */ 556 static int 557 fifo_close(ap) 558 struct vop_close_args /* { 559 struct vnode *a_vp; 560 int a_fflag; 561 struct ucred *a_cred; 562 struct thread *a_td; 563 } */ *ap; 564 { 565 struct vnode *vp = ap->a_vp; 566 struct thread *td = ap->a_td; 567 struct fifoinfo *fip = vp->v_fifoinfo; 568 569 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 570 571 ASSERT_VOP_LOCKED(vp, "fifo_close"); 572 if (ap->a_fflag & FREAD) { 573 fip->fi_readers--; 574 if (fip->fi_readers == 0) 575 socantsendmore(fip->fi_writesock); 576 } 577 if (ap->a_fflag & FWRITE) { 578 fip->fi_writers--; 579 if (fip->fi_writers == 0) 580 socantrcvmore(fip->fi_readsock); 581 } 582 fifo_cleanup(vp); 583 VOP_UNLOCK(vp, 0, td); 584 return (0); 585 } 586 587 /* 588 * Print out internal contents of a fifo vnode. 589 */ 590 int 591 fifo_printinfo(vp) 592 struct vnode *vp; 593 { 594 register struct fifoinfo *fip = vp->v_fifoinfo; 595 596 printf(", fifo with %ld readers and %ld writers", 597 fip->fi_readers, fip->fi_writers); 598 return (0); 599 } 600 601 /* 602 * Print out the contents of a fifo vnode. 603 */ 604 static int 605 fifo_print(ap) 606 struct vop_print_args /* { 607 struct vnode *a_vp; 608 } */ *ap; 609 { 610 fifo_printinfo(ap->a_vp); 611 printf("\n"); 612 return (0); 613 } 614 615 /* 616 * Return POSIX pathconf information applicable to fifo's. 617 */ 618 static int 619 fifo_pathconf(ap) 620 struct vop_pathconf_args /* { 621 struct vnode *a_vp; 622 int a_name; 623 int *a_retval; 624 } */ *ap; 625 { 626 627 switch (ap->a_name) { 628 case _PC_LINK_MAX: 629 *ap->a_retval = LINK_MAX; 630 return (0); 631 case _PC_PIPE_BUF: 632 *ap->a_retval = PIPE_BUF; 633 return (0); 634 case _PC_CHOWN_RESTRICTED: 635 *ap->a_retval = 1; 636 return (0); 637 default: 638 return (EINVAL); 639 } 640 /* NOTREACHED */ 641 } 642 643 /* 644 * Fifo advisory byte-level locks. 645 */ 646 /* ARGSUSED */ 647 static int 648 fifo_advlock(ap) 649 struct vop_advlock_args /* { 650 struct vnode *a_vp; 651 caddr_t a_id; 652 int a_op; 653 struct flock *a_fl; 654 int a_flags; 655 } */ *ap; 656 { 657 658 return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL); 659 }
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