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 1.26 2006/04/14 01:07:38 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/vnode.h> 45 #include <sys/socket.h> 46 #include <sys/socketvar.h> 47 #include <sys/filio.h> 48 #include <sys/fcntl.h> 49 #include <sys/file.h> 50 #include <sys/event.h> 51 #include <sys/poll.h> 52 #include <sys/un.h> 53 #include "fifo.h" 54 55 /* 56 * This structure is associated with the FIFO vnode and stores 57 * the state associated with the FIFO. 58 */ 59 struct fifoinfo { 60 struct socket *fi_readsock; 61 struct socket *fi_writesock; 62 long fi_readers; 63 long fi_writers; 64 }; 65 66 static int fifo_badop (void); 67 static int fifo_print (struct vop_print_args *); 68 static int fifo_lookup (struct vop_old_lookup_args *); 69 static int fifo_open (struct vop_open_args *); 70 static int fifo_close (struct vop_close_args *); 71 static int fifo_read (struct vop_read_args *); 72 static int fifo_write (struct vop_write_args *); 73 static int fifo_ioctl (struct vop_ioctl_args *); 74 static int fifo_poll (struct vop_poll_args *); 75 static int fifo_kqfilter (struct vop_kqfilter_args *); 76 static int fifo_inactive (struct vop_inactive_args *); 77 static int fifo_bmap (struct vop_bmap_args *); 78 static int fifo_pathconf (struct vop_pathconf_args *); 79 static int fifo_advlock (struct vop_advlock_args *); 80 81 static void filt_fifordetach(struct knote *kn); 82 static int filt_fiforead(struct knote *kn, long hint); 83 static void filt_fifowdetach(struct knote *kn); 84 static int filt_fifowrite(struct knote *kn, long hint); 85 86 static struct filterops fiforead_filtops = 87 { 1, NULL, filt_fifordetach, filt_fiforead }; 88 static struct filterops fifowrite_filtops = 89 { 1, NULL, filt_fifowdetach, filt_fifowrite }; 90 91 struct vop_ops *fifo_vnode_vops; 92 static struct vnodeopv_entry_desc fifo_vnodeop_entries[] = { 93 { &vop_default_desc, (vnodeopv_entry_t) vop_defaultop }, 94 { &vop_access_desc, (vnodeopv_entry_t) vop_ebadf }, 95 { &vop_advlock_desc, (vnodeopv_entry_t) fifo_advlock }, 96 { &vop_bmap_desc, (vnodeopv_entry_t) fifo_bmap }, 97 { &vop_close_desc, (vnodeopv_entry_t) fifo_close }, 98 { &vop_old_create_desc, (vnodeopv_entry_t) fifo_badop }, 99 { &vop_getattr_desc, (vnodeopv_entry_t) vop_ebadf }, 100 { &vop_inactive_desc, (vnodeopv_entry_t) fifo_inactive }, 101 { &vop_ioctl_desc, (vnodeopv_entry_t) fifo_ioctl }, 102 { &vop_kqfilter_desc, (vnodeopv_entry_t) fifo_kqfilter }, 103 { &vop_old_link_desc, (vnodeopv_entry_t) fifo_badop }, 104 { &vop_old_lookup_desc, (vnodeopv_entry_t) fifo_lookup }, 105 { &vop_old_mkdir_desc, (vnodeopv_entry_t) fifo_badop }, 106 { &vop_old_mknod_desc, (vnodeopv_entry_t) fifo_badop }, 107 { &vop_open_desc, (vnodeopv_entry_t) fifo_open }, 108 { &vop_pathconf_desc, (vnodeopv_entry_t) fifo_pathconf }, 109 { &vop_poll_desc, (vnodeopv_entry_t) fifo_poll }, 110 { &vop_print_desc, (vnodeopv_entry_t) fifo_print }, 111 { &vop_read_desc, (vnodeopv_entry_t) fifo_read }, 112 { &vop_readdir_desc, (vnodeopv_entry_t) fifo_badop }, 113 { &vop_readlink_desc, (vnodeopv_entry_t) fifo_badop }, 114 { &vop_reallocblks_desc, (vnodeopv_entry_t) fifo_badop }, 115 { &vop_reclaim_desc, (vnodeopv_entry_t) vop_null }, 116 { &vop_old_remove_desc, (vnodeopv_entry_t) fifo_badop }, 117 { &vop_old_rename_desc, (vnodeopv_entry_t) fifo_badop }, 118 { &vop_old_rmdir_desc, (vnodeopv_entry_t) fifo_badop }, 119 { &vop_setattr_desc, (vnodeopv_entry_t) vop_ebadf }, 120 { &vop_old_symlink_desc, (vnodeopv_entry_t) fifo_badop }, 121 { &vop_write_desc, (vnodeopv_entry_t) fifo_write }, 122 { NULL, NULL } 123 }; 124 static struct vnodeopv_desc fifo_vnodeop_opv_desc = 125 { &fifo_vnode_vops, fifo_vnodeop_entries, 0 }; 126 127 VNODEOP_SET(fifo_vnodeop_opv_desc); 128 129 static MALLOC_DEFINE(M_FIFOINFO, "Fifo info", "Fifo info entries"); 130 131 /* 132 * fifo_vnoperate(struct vnodeop_desc *a_desc, ...) 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 thread *a_td) 160 */ 161 /* ARGSUSED */ 162 static int 163 fifo_open(struct vop_open_args *ap) 164 { 165 struct vnode *vp = ap->a_vp; 166 struct fifoinfo *fip; 167 struct socket *rso, *wso; 168 int error; 169 170 if ((fip = vp->v_fifoinfo) == NULL) { 171 MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_FIFOINFO, M_WAITOK); 172 vp->v_fifoinfo = fip; 173 error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0, ap->a_td); 174 if (error) { 175 free(fip, M_FIFOINFO); 176 vp->v_fifoinfo = NULL; 177 return (error); 178 } 179 fip->fi_readsock = rso; 180 error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0, ap->a_td); 181 if (error) { 182 soclose(rso); 183 free(fip, M_FIFOINFO); 184 vp->v_fifoinfo = NULL; 185 return (error); 186 } 187 fip->fi_writesock = wso; 188 error = unp_connect2(wso, rso); 189 if (error) { 190 soclose(wso); 191 soclose(rso); 192 free(fip, M_FIFOINFO); 193 vp->v_fifoinfo = NULL; 194 return (error); 195 } 196 fip->fi_readers = fip->fi_writers = 0; 197 wso->so_snd.sb_lowat = PIPE_BUF; 198 rso->so_state |= SS_CANTRCVMORE; 199 } 200 if (ap->a_mode & FREAD) { 201 fip->fi_readers++; 202 if (fip->fi_readers == 1) { 203 fip->fi_writesock->so_state &= ~SS_CANTSENDMORE; 204 if (fip->fi_writers > 0) { 205 wakeup((caddr_t)&fip->fi_writers); 206 sowwakeup(fip->fi_writesock); 207 } 208 } 209 } 210 if (ap->a_mode & FWRITE) { 211 fip->fi_writers++; 212 if (fip->fi_writers == 1) { 213 fip->fi_readsock->so_state &= ~SS_CANTRCVMORE; 214 if (fip->fi_readers > 0) { 215 wakeup((caddr_t)&fip->fi_readers); 216 sorwakeup(fip->fi_writesock); 217 } 218 } 219 } 220 if ((ap->a_mode & FREAD) && (ap->a_mode & O_NONBLOCK) == 0) { 221 if (fip->fi_writers == 0) { 222 VOP_UNLOCK(vp, 0, ap->a_td); 223 error = tsleep((caddr_t)&fip->fi_readers, 224 PCATCH, "fifoor", 0); 225 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, ap->a_td); 226 if (error) 227 goto bad; 228 /* 229 * We must have got woken up because we had a writer. 230 * That (and not still having one) is the condition 231 * that we must wait for. 232 */ 233 } 234 } 235 if (ap->a_mode & FWRITE) { 236 if (ap->a_mode & O_NONBLOCK) { 237 if (fip->fi_readers == 0) { 238 error = ENXIO; 239 goto bad; 240 } 241 } else { 242 if (fip->fi_readers == 0) { 243 VOP_UNLOCK(vp, 0, ap->a_td); 244 error = tsleep((caddr_t)&fip->fi_writers, 245 PCATCH, "fifoow", 0); 246 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, ap->a_td); 247 if (error) 248 goto bad; 249 /* 250 * We must have got woken up because we had 251 * a reader. That (and not still having one) 252 * is the condition that we must wait for. 253 */ 254 } 255 } 256 } 257 return (vop_stdopen(ap)); 258 bad: 259 vop_stdopen(ap); /* bump opencount/writecount as appropriate */ 260 VOP_CLOSE(vp, ap->a_mode, ap->a_td); 261 return (error); 262 } 263 264 /* 265 * Vnode op for read 266 * 267 * fifo_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag, 268 * struct ucred *a_cred) 269 */ 270 /* ARGSUSED */ 271 static int 272 fifo_read(struct vop_read_args *ap) 273 { 274 struct uio *uio = ap->a_uio; 275 struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock; 276 struct thread *td = uio->uio_td; 277 int error, startresid; 278 279 #ifdef DIAGNOSTIC 280 if (uio->uio_rw != UIO_READ) 281 panic("fifo_read mode"); 282 #endif 283 if (uio->uio_resid == 0) 284 return (0); 285 if (ap->a_ioflag & IO_NDELAY) 286 rso->so_state |= SS_NBIO; 287 startresid = uio->uio_resid; 288 VOP_UNLOCK(ap->a_vp, 0, td); 289 error = soreceive(rso, (struct sockaddr **)0, uio, (struct mbuf **)0, 290 (struct mbuf **)0, (int *)0); 291 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, td); 292 if (ap->a_ioflag & IO_NDELAY) 293 rso->so_state &= ~SS_NBIO; 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; 310 311 #ifdef DIAGNOSTIC 312 if (ap->a_uio->uio_rw != UIO_WRITE) 313 panic("fifo_write mode"); 314 #endif 315 if (ap->a_ioflag & IO_NDELAY) 316 wso->so_state |= SS_NBIO; 317 VOP_UNLOCK(ap->a_vp, 0, td); 318 error = sosend(wso, (struct sockaddr *)0, ap->a_uio, 0, 319 (struct mbuf *)0, 0, td); 320 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY, td); 321 if (ap->a_ioflag & IO_NDELAY) 322 wso->so_state &= ~SS_NBIO; 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, struct thread *a_td) 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_command == FIONBIO) 340 return (0); 341 if (ap->a_fflag & FREAD) { 342 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 343 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_td); 344 if (error) 345 return (error); 346 } 347 if (ap->a_fflag & FWRITE) { 348 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 349 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_td); 350 if (error) 351 return (error); 352 } 353 return (0); 354 } 355 356 /* 357 * fifo_kqfilter(struct vnode *a_vp, struct knote *a_kn) 358 */ 359 /* ARGSUSED */ 360 static int 361 fifo_kqfilter(struct vop_kqfilter_args *ap) 362 { 363 struct fifoinfo *fi = ap->a_vp->v_fifoinfo; 364 struct socket *so; 365 struct sockbuf *sb; 366 367 switch (ap->a_kn->kn_filter) { 368 case EVFILT_READ: 369 ap->a_kn->kn_fop = &fiforead_filtops; 370 so = fi->fi_readsock; 371 sb = &so->so_rcv; 372 break; 373 case EVFILT_WRITE: 374 ap->a_kn->kn_fop = &fifowrite_filtops; 375 so = fi->fi_writesock; 376 sb = &so->so_snd; 377 break; 378 default: 379 return (1); 380 } 381 382 ap->a_kn->kn_hook = (caddr_t)so; 383 384 SLIST_INSERT_HEAD(&sb->sb_sel.si_note, ap->a_kn, kn_selnext); 385 sb->sb_flags |= SB_KNOTE; 386 387 return (0); 388 } 389 390 static void 391 filt_fifordetach(struct knote *kn) 392 { 393 struct socket *so = (struct socket *)kn->kn_hook; 394 395 SLIST_REMOVE(&so->so_rcv.sb_sel.si_note, kn, knote, kn_selnext); 396 if (SLIST_EMPTY(&so->so_rcv.sb_sel.si_note)) 397 so->so_rcv.sb_flags &= ~SB_KNOTE; 398 } 399 400 static int 401 filt_fiforead(struct knote *kn, long hint) 402 { 403 struct socket *so = (struct socket *)kn->kn_hook; 404 405 kn->kn_data = so->so_rcv.sb_cc; 406 if (so->so_state & SS_CANTRCVMORE) { 407 kn->kn_flags |= EV_EOF; 408 return (1); 409 } 410 kn->kn_flags &= ~EV_EOF; 411 return (kn->kn_data > 0); 412 } 413 414 static void 415 filt_fifowdetach(struct knote *kn) 416 { 417 struct socket *so = (struct socket *)kn->kn_hook; 418 419 SLIST_REMOVE(&so->so_snd.sb_sel.si_note, kn, knote, kn_selnext); 420 if (SLIST_EMPTY(&so->so_snd.sb_sel.si_note)) 421 so->so_snd.sb_flags &= ~SB_KNOTE; 422 } 423 424 static int 425 filt_fifowrite(struct knote *kn, long hint) 426 { 427 struct socket *so = (struct socket *)kn->kn_hook; 428 429 kn->kn_data = sbspace(&so->so_snd); 430 if (so->so_state & SS_CANTSENDMORE) { 431 kn->kn_flags |= EV_EOF; 432 return (1); 433 } 434 kn->kn_flags &= ~EV_EOF; 435 return (kn->kn_data >= so->so_snd.sb_lowat); 436 } 437 438 /* 439 * fifo_poll(struct vnode *a_vp, int a_events, struct ucred *a_cred, 440 * struct thread *a_td) 441 */ 442 /* ARGSUSED */ 443 static int 444 fifo_poll(struct vop_poll_args *ap) 445 { 446 struct file filetmp; 447 int events, revents = 0; 448 449 events = ap->a_events & 450 (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND); 451 if (events) { 452 /* 453 * If POLLIN or POLLRDNORM is requested and POLLINIGNEOF is 454 * not, then convert the first two to the last one. This 455 * tells the socket poll function to ignore EOF so that we 456 * block if there is no writer (and no data). Callers can 457 * set POLLINIGNEOF to get non-blocking behavior. 458 */ 459 if (events & (POLLIN | POLLRDNORM) && 460 !(events & POLLINIGNEOF)) { 461 events &= ~(POLLIN | POLLRDNORM); 462 events |= POLLINIGNEOF; 463 } 464 465 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 466 if (filetmp.f_data) 467 revents |= soo_poll(&filetmp, events, ap->a_cred, 468 ap->a_td); 469 470 /* Reverse the above conversion. */ 471 if ((revents & POLLINIGNEOF) && 472 !(ap->a_events & POLLINIGNEOF)) { 473 revents |= (ap->a_events & (POLLIN | POLLRDNORM)); 474 revents &= ~POLLINIGNEOF; 475 } 476 } 477 events = ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND); 478 if (events) { 479 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 480 if (filetmp.f_data) 481 revents |= soo_poll(&filetmp, events, ap->a_cred, 482 ap->a_td); 483 } 484 return (revents); 485 } 486 487 /* 488 * fifo_inactive(struct vnode *a_vp, struct thread *a_td) 489 */ 490 static int 491 fifo_inactive(struct vop_inactive_args *ap) 492 { 493 return (0); 494 } 495 496 /* 497 * This is a noop, simply returning what one has been given. 498 * 499 * fifo_bmap(struct vnode *a_vp, off_t a_loffset, struct vnode **a_vpp, 500 * off_t *a_doffsetp, int *a_runp, int *a_runb) 501 */ 502 static int 503 fifo_bmap(struct vop_bmap_args *ap) 504 { 505 if (ap->a_vpp != NULL) 506 *ap->a_vpp = ap->a_vp; 507 if (ap->a_doffsetp != NULL) 508 *ap->a_doffsetp = ap->a_loffset; 509 if (ap->a_runp != NULL) 510 *ap->a_runp = 0; 511 if (ap->a_runb != NULL) 512 *ap->a_runb = 0; 513 return (0); 514 } 515 516 /* 517 * Device close routine 518 * 519 * fifo_close(struct vnode *a_vp, int a_fflag, struct ucred *a_cred, 520 * struct thread *a_td) 521 */ 522 /* ARGSUSED */ 523 static int 524 fifo_close(struct vop_close_args *ap) 525 { 526 struct vnode *vp = ap->a_vp; 527 struct fifoinfo *fip = vp->v_fifoinfo; 528 int error1, error2; 529 530 if (ap->a_fflag & FREAD) { 531 fip->fi_readers--; 532 if (fip->fi_readers == 0) 533 socantsendmore(fip->fi_writesock); 534 } 535 if (ap->a_fflag & FWRITE) { 536 fip->fi_writers--; 537 if (fip->fi_writers == 0) 538 socantrcvmore(fip->fi_readsock); 539 } 540 if (vp->v_usecount > 1) { 541 vop_stdclose(ap); 542 return (0); 543 } 544 error1 = soclose(fip->fi_readsock); 545 error2 = soclose(fip->fi_writesock); 546 FREE(fip, M_FIFOINFO); 547 vp->v_fifoinfo = NULL; 548 if (error1) 549 return (error1); 550 vop_stdclose(ap); 551 return (error2); 552 } 553 554 555 /* 556 * Print out internal contents of a fifo vnode. 557 */ 558 int 559 fifo_printinfo(struct vnode *vp) 560 { 561 struct fifoinfo *fip = vp->v_fifoinfo; 562 563 printf(", fifo with %ld readers and %ld writers", 564 fip->fi_readers, fip->fi_writers); 565 return (0); 566 } 567 568 /* 569 * Print out the contents of a fifo vnode. 570 * 571 * fifo_print(struct vnode *a_vp) 572 */ 573 static int 574 fifo_print(struct vop_print_args *ap) 575 { 576 printf("tag VT_NON"); 577 fifo_printinfo(ap->a_vp); 578 printf("\n"); 579 return (0); 580 } 581 582 /* 583 * Return POSIX pathconf information applicable to fifo's. 584 * 585 * fifo_pathconf(struct vnode *a_vp, int a_name, int *a_retval) 586 */ 587 int 588 fifo_pathconf(struct vop_pathconf_args *ap) 589 { 590 switch (ap->a_name) { 591 case _PC_LINK_MAX: 592 *ap->a_retval = LINK_MAX; 593 return (0); 594 case _PC_PIPE_BUF: 595 *ap->a_retval = PIPE_BUF; 596 return (0); 597 case _PC_CHOWN_RESTRICTED: 598 *ap->a_retval = 1; 599 return (0); 600 default: 601 return (EINVAL); 602 } 603 /* NOTREACHED */ 604 } 605 606 /* 607 * Fifo advisory byte-level locks. 608 * 609 * fifo_advlock(struct vnode *a_vp, caddr_t a_id, int a_op, struct flock *a_fl, 610 * int a_flags) 611 */ 612 /* ARGSUSED */ 613 static int 614 fifo_advlock(struct vop_advlock_args *ap) 615 { 616 return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL); 617 } 618 619 /* 620 * Fifo bad operation 621 */ 622 static int 623 fifo_badop(void) 624 { 625 panic("fifo_badop called"); 626 /* NOTREACHED */ 627 } 628