Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/miscfs/fifofs/fifo_vnops.c
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1 /* $NetBSD: fifo_vnops.c,v 1.57 2006/11/16 01:33:38 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1990, 1993, 1995 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)fifo_vnops.c 8.10 (Berkeley) 5/27/95 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: fifo_vnops.c,v 1.57 2006/11/16 01:33:38 christos Exp $"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/proc.h> 40 #include <sys/time.h> 41 #include <sys/namei.h> 42 #include <sys/vnode.h> 43 #include <sys/socket.h> 44 #include <sys/protosw.h> 45 #include <sys/socketvar.h> 46 #include <sys/stat.h> 47 #include <sys/ioctl.h> 48 #include <sys/file.h> 49 #include <sys/errno.h> 50 #include <sys/malloc.h> 51 #include <sys/un.h> 52 #include <sys/poll.h> 53 #include <sys/event.h> 54 55 #include <miscfs/fifofs/fifo.h> 56 #include <miscfs/genfs/genfs.h> 57 58 /* 59 * This structure is associated with the FIFO vnode and stores 60 * the state associated with the FIFO. 61 */ 62 struct fifoinfo { 63 struct socket *fi_readsock; 64 struct socket *fi_writesock; 65 long fi_readers; 66 long fi_writers; 67 }; 68 69 int (**fifo_vnodeop_p)(void *); 70 const struct vnodeopv_entry_desc fifo_vnodeop_entries[] = { 71 { &vop_default_desc, vn_default_error }, 72 { &vop_lookup_desc, fifo_lookup }, /* lookup */ 73 { &vop_create_desc, fifo_create }, /* create */ 74 { &vop_mknod_desc, fifo_mknod }, /* mknod */ 75 { &vop_open_desc, fifo_open }, /* open */ 76 { &vop_close_desc, fifo_close }, /* close */ 77 { &vop_access_desc, fifo_access }, /* access */ 78 { &vop_getattr_desc, fifo_getattr }, /* getattr */ 79 { &vop_setattr_desc, fifo_setattr }, /* setattr */ 80 { &vop_read_desc, fifo_read }, /* read */ 81 { &vop_write_desc, fifo_write }, /* write */ 82 { &vop_lease_desc, fifo_lease_check }, /* lease */ 83 { &vop_ioctl_desc, fifo_ioctl }, /* ioctl */ 84 { &vop_poll_desc, fifo_poll }, /* poll */ 85 { &vop_kqfilter_desc, fifo_kqfilter }, /* kqfilter */ 86 { &vop_revoke_desc, fifo_revoke }, /* revoke */ 87 { &vop_mmap_desc, fifo_mmap }, /* mmap */ 88 { &vop_fsync_desc, fifo_fsync }, /* fsync */ 89 { &vop_seek_desc, fifo_seek }, /* seek */ 90 { &vop_remove_desc, fifo_remove }, /* remove */ 91 { &vop_link_desc, fifo_link }, /* link */ 92 { &vop_rename_desc, fifo_rename }, /* rename */ 93 { &vop_mkdir_desc, fifo_mkdir }, /* mkdir */ 94 { &vop_rmdir_desc, fifo_rmdir }, /* rmdir */ 95 { &vop_symlink_desc, fifo_symlink }, /* symlink */ 96 { &vop_readdir_desc, fifo_readdir }, /* readdir */ 97 { &vop_readlink_desc, fifo_readlink }, /* readlink */ 98 { &vop_abortop_desc, fifo_abortop }, /* abortop */ 99 { &vop_inactive_desc, fifo_inactive }, /* inactive */ 100 { &vop_reclaim_desc, fifo_reclaim }, /* reclaim */ 101 { &vop_lock_desc, fifo_lock }, /* lock */ 102 { &vop_unlock_desc, fifo_unlock }, /* unlock */ 103 { &vop_bmap_desc, fifo_bmap }, /* bmap */ 104 { &vop_strategy_desc, fifo_strategy }, /* strategy */ 105 { &vop_print_desc, fifo_print }, /* print */ 106 { &vop_islocked_desc, fifo_islocked }, /* islocked */ 107 { &vop_pathconf_desc, fifo_pathconf }, /* pathconf */ 108 { &vop_advlock_desc, fifo_advlock }, /* advlock */ 109 { &vop_bwrite_desc, fifo_bwrite }, /* bwrite */ 110 { &vop_putpages_desc, fifo_putpages }, /* putpages */ 111 { (struct vnodeop_desc*)NULL, (int(*)(void *))NULL } 112 }; 113 const struct vnodeopv_desc fifo_vnodeop_opv_desc = 114 { &fifo_vnodeop_p, fifo_vnodeop_entries }; 115 116 /* 117 * Trivial lookup routine that always fails. 118 */ 119 /* ARGSUSED */ 120 int 121 fifo_lookup(void *v) 122 { 123 struct vop_lookup_args /* { 124 struct vnode *a_dvp; 125 struct vnode **a_vpp; 126 struct componentname *a_cnp; 127 } */ *ap = v; 128 129 *ap->a_vpp = NULL; 130 return (ENOTDIR); 131 } 132 133 /* 134 * Open called to set up a new instance of a fifo or 135 * to find an active instance of a fifo. 136 */ 137 /* ARGSUSED */ 138 int 139 fifo_open(void *v) 140 { 141 struct vop_open_args /* { 142 struct vnode *a_vp; 143 int a_mode; 144 kauth_cred_t a_cred; 145 struct lwp *a_l; 146 } */ *ap = v; 147 struct vnode *vp; 148 struct fifoinfo *fip; 149 struct lwp *l = ap->a_l; 150 struct proc *p; 151 struct socket *rso, *wso; 152 int error; 153 154 vp = ap->a_vp; 155 p = ap->a_l->l_proc; 156 157 if ((fip = vp->v_fifoinfo) == NULL) { 158 MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK); 159 vp->v_fifoinfo = fip; 160 error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0, l); 161 if (error != 0) { 162 free(fip, M_VNODE); 163 vp->v_fifoinfo = NULL; 164 return (error); 165 } 166 fip->fi_readsock = rso; 167 error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0, l); 168 if (error != 0) { 169 (void)soclose(rso); 170 free(fip, M_VNODE); 171 vp->v_fifoinfo = NULL; 172 return (error); 173 } 174 fip->fi_writesock = wso; 175 if ((error = unp_connect2(wso, rso, PRU_CONNECT2)) != 0) { 176 (void)soclose(wso); 177 (void)soclose(rso); 178 free(fip, M_VNODE); 179 vp->v_fifoinfo = NULL; 180 return (error); 181 } 182 fip->fi_readers = fip->fi_writers = 0; 183 wso->so_state |= SS_CANTRCVMORE; 184 rso->so_state |= SS_CANTSENDMORE; 185 } 186 if (ap->a_mode & FREAD) { 187 if (fip->fi_readers++ == 0) { 188 fip->fi_writesock->so_state &= ~SS_CANTSENDMORE; 189 if (fip->fi_writers > 0) 190 wakeup(&fip->fi_writers); 191 } 192 } 193 if (ap->a_mode & FWRITE) { 194 if (fip->fi_writers++ == 0) { 195 fip->fi_readsock->so_state &= ~SS_CANTRCVMORE; 196 if (fip->fi_readers > 0) 197 wakeup(&fip->fi_readers); 198 } 199 } 200 if (ap->a_mode & FREAD) { 201 if (ap->a_mode & O_NONBLOCK) { 202 } else { 203 while (!soreadable(fip->fi_readsock) && fip->fi_writers == 0) { 204 VOP_UNLOCK(vp, 0); 205 error = tsleep(&fip->fi_readers, 206 PCATCH | PSOCK, "fifor", 0); 207 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 208 if (error) 209 goto bad; 210 } 211 } 212 } 213 if (ap->a_mode & FWRITE) { 214 if (ap->a_mode & O_NONBLOCK) { 215 if (fip->fi_readers == 0) { 216 error = ENXIO; 217 goto bad; 218 } 219 } else { 220 while (fip->fi_readers == 0) { 221 VOP_UNLOCK(vp, 0); 222 error = tsleep(&fip->fi_writers, 223 PCATCH | PSOCK, "fifow", 0); 224 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 225 if (error) 226 goto bad; 227 } 228 } 229 } 230 return (0); 231 bad: 232 VOP_CLOSE(vp, ap->a_mode, ap->a_cred, ap->a_l); 233 return (error); 234 } 235 236 /* 237 * Vnode op for read 238 */ 239 /* ARGSUSED */ 240 int 241 fifo_read(void *v) 242 { 243 struct vop_read_args /* { 244 struct vnode *a_vp; 245 struct uio *a_uio; 246 int a_ioflag; 247 kauth_cred_t a_cred; 248 } */ *ap = v; 249 struct uio *uio; 250 struct socket *rso; 251 int error; 252 size_t startresid; 253 254 uio = ap->a_uio; 255 rso = ap->a_vp->v_fifoinfo->fi_readsock; 256 #ifdef DIAGNOSTIC 257 if (uio->uio_rw != UIO_READ) 258 panic("fifo_read mode"); 259 #endif 260 if (uio->uio_resid == 0) 261 return (0); 262 if (ap->a_ioflag & IO_NDELAY) 263 rso->so_state |= SS_NBIO; 264 startresid = uio->uio_resid; 265 VOP_UNLOCK(ap->a_vp, 0); 266 error = (*rso->so_receive)(rso, (struct mbuf **)0, uio, 267 (struct mbuf **)0, (struct mbuf **)0, (int *)0); 268 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); 269 /* 270 * Clear EOF indication after first such return. 271 */ 272 if (uio->uio_resid == startresid) 273 rso->so_state &= ~SS_CANTRCVMORE; 274 if (ap->a_ioflag & IO_NDELAY) { 275 rso->so_state &= ~SS_NBIO; 276 if (error == EWOULDBLOCK && 277 ap->a_vp->v_fifoinfo->fi_writers == 0) 278 error = 0; 279 } 280 return (error); 281 } 282 283 /* 284 * Vnode op for write 285 */ 286 /* ARGSUSED */ 287 int 288 fifo_write(void *v) 289 { 290 struct vop_write_args /* { 291 struct vnode *a_vp; 292 struct uio *a_uio; 293 int a_ioflag; 294 kauth_cred_t a_cred; 295 } */ *ap = v; 296 struct socket *wso; 297 int error; 298 299 wso = ap->a_vp->v_fifoinfo->fi_writesock; 300 #ifdef DIAGNOSTIC 301 if (ap->a_uio->uio_rw != UIO_WRITE) 302 panic("fifo_write mode"); 303 #endif 304 if (ap->a_ioflag & IO_NDELAY) 305 wso->so_state |= SS_NBIO; 306 VOP_UNLOCK(ap->a_vp, 0); 307 error = (*wso->so_send)(wso, (struct mbuf *)0, ap->a_uio, 0, 308 (struct mbuf *)0, 0, curlwp /*XXX*/); 309 vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY); 310 if (ap->a_ioflag & IO_NDELAY) 311 wso->so_state &= ~SS_NBIO; 312 return (error); 313 } 314 315 /* 316 * Device ioctl operation. 317 */ 318 /* ARGSUSED */ 319 int 320 fifo_ioctl(void *v) 321 { 322 struct vop_ioctl_args /* { 323 struct vnode *a_vp; 324 u_long a_command; 325 void *a_data; 326 int a_fflag; 327 kauth_cred_t a_cred; 328 struct lwp *a_l; 329 } */ *ap = v; 330 struct file filetmp; 331 int error; 332 333 if (ap->a_command == FIONBIO) 334 return (0); 335 if (ap->a_fflag & FREAD) { 336 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 337 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_l); 338 if (error) 339 return (error); 340 } 341 if (ap->a_fflag & FWRITE) { 342 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 343 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_l); 344 if (error) 345 return (error); 346 } 347 return (0); 348 } 349 350 /* ARGSUSED */ 351 int 352 fifo_poll(void *v) 353 { 354 struct vop_poll_args /* { 355 struct vnode *a_vp; 356 int a_events; 357 struct lwp *a_l; 358 } */ *ap = v; 359 struct file filetmp; 360 int revents; 361 362 revents = 0; 363 if (ap->a_events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) { 364 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; 365 if (filetmp.f_data) 366 revents |= soo_poll(&filetmp, ap->a_events, ap->a_l); 367 } 368 if (ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND)) { 369 filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock; 370 if (filetmp.f_data) 371 revents |= soo_poll(&filetmp, ap->a_events, ap->a_l); 372 } 373 374 return (revents); 375 } 376 377 int 378 fifo_inactive(void *v) 379 { 380 struct vop_inactive_args /* { 381 struct vnode *a_vp; 382 struct lwp *a_l; 383 } */ *ap = v; 384 385 VOP_UNLOCK(ap->a_vp, 0); 386 return (0); 387 } 388 389 /* 390 * This is a noop, simply returning what one has been given. 391 */ 392 int 393 fifo_bmap(void *v) 394 { 395 struct vop_bmap_args /* { 396 struct vnode *a_vp; 397 daddr_t a_bn; 398 struct vnode **a_vpp; 399 daddr_t *a_bnp; 400 int *a_runp; 401 } */ *ap = v; 402 403 if (ap->a_vpp != NULL) 404 *ap->a_vpp = ap->a_vp; 405 if (ap->a_bnp != NULL) 406 *ap->a_bnp = ap->a_bn; 407 if (ap->a_runp != NULL) 408 *ap->a_runp = 0; 409 return (0); 410 } 411 412 /* 413 * Device close routine 414 */ 415 /* ARGSUSED */ 416 int 417 fifo_close(void *v) 418 { 419 struct vop_close_args /* { 420 struct vnode *a_vp; 421 int a_fflag; 422 kauth_cred_t a_cred; 423 struct lwp *a_l; 424 } */ *ap = v; 425 struct vnode *vp; 426 struct fifoinfo *fip; 427 int isrevoke; 428 429 vp = ap->a_vp; 430 fip = vp->v_fifoinfo; 431 isrevoke = (ap->a_fflag & (FREAD | FWRITE | FNONBLOCK)) == FNONBLOCK; 432 if (isrevoke) { 433 if (fip->fi_readers != 0) { 434 fip->fi_readers = 0; 435 socantsendmore(fip->fi_writesock); 436 } 437 if (fip->fi_writers != 0) { 438 fip->fi_writers = 0; 439 socantrcvmore(fip->fi_readsock); 440 } 441 } else { 442 if ((ap->a_fflag & FREAD) && --fip->fi_readers == 0) 443 socantsendmore(fip->fi_writesock); 444 if ((ap->a_fflag & FWRITE) && --fip->fi_writers == 0) 445 socantrcvmore(fip->fi_readsock); 446 } 447 /* Shut down if all readers and writers are gone. */ 448 if ((fip->fi_readers + fip->fi_writers) == 0) { 449 (void) soclose(fip->fi_readsock); 450 (void) soclose(fip->fi_writesock); 451 FREE(fip, M_VNODE); 452 vp->v_fifoinfo = NULL; 453 } 454 return (0); 455 } 456 457 /* 458 * Print out the contents of a fifo vnode. 459 */ 460 int 461 fifo_print(void *v) 462 { 463 struct vop_print_args /* { 464 struct vnode *a_vp; 465 } */ *ap = v; 466 467 printf("tag VT_NON"); 468 fifo_printinfo(ap->a_vp); 469 printf("\n"); 470 return 0; 471 } 472 473 /* 474 * Print out internal contents of a fifo vnode. 475 */ 476 void 477 fifo_printinfo(struct vnode *vp) 478 { 479 struct fifoinfo *fip; 480 481 fip = vp->v_fifoinfo; 482 printf(", fifo with %ld readers and %ld writers", 483 fip->fi_readers, fip->fi_writers); 484 } 485 486 /* 487 * Return POSIX pathconf information applicable to fifo's. 488 */ 489 int 490 fifo_pathconf(void *v) 491 { 492 struct vop_pathconf_args /* { 493 struct vnode *a_vp; 494 int a_name; 495 register_t *a_retval; 496 } */ *ap = v; 497 498 switch (ap->a_name) { 499 case _PC_LINK_MAX: 500 *ap->a_retval = LINK_MAX; 501 return (0); 502 case _PC_PIPE_BUF: 503 *ap->a_retval = PIPE_BUF; 504 return (0); 505 case _PC_CHOWN_RESTRICTED: 506 *ap->a_retval = 1; 507 return (0); 508 case _PC_SYNC_IO: 509 *ap->a_retval = 1; 510 return (0); 511 default: 512 return (EINVAL); 513 } 514 /* NOTREACHED */ 515 } 516 517 static void 518 filt_fifordetach(struct knote *kn) 519 { 520 struct socket *so; 521 522 so = (struct socket *)kn->kn_hook; 523 SLIST_REMOVE(&so->so_rcv.sb_sel.sel_klist, kn, knote, kn_selnext); 524 if (SLIST_EMPTY(&so->so_rcv.sb_sel.sel_klist)) 525 so->so_rcv.sb_flags &= ~SB_KNOTE; 526 } 527 528 static int 529 filt_fiforead(struct knote *kn, long hint) 530 { 531 struct socket *so; 532 533 so = (struct socket *)kn->kn_hook; 534 kn->kn_data = so->so_rcv.sb_cc; 535 if (so->so_state & SS_CANTRCVMORE) { 536 kn->kn_flags |= EV_EOF; 537 return (1); 538 } 539 kn->kn_flags &= ~EV_EOF; 540 return (kn->kn_data > 0); 541 } 542 543 static void 544 filt_fifowdetach(struct knote *kn) 545 { 546 struct socket *so; 547 548 so = (struct socket *)kn->kn_hook; 549 SLIST_REMOVE(&so->so_snd.sb_sel.sel_klist, kn, knote, kn_selnext); 550 if (SLIST_EMPTY(&so->so_snd.sb_sel.sel_klist)) 551 so->so_snd.sb_flags &= ~SB_KNOTE; 552 } 553 554 static int 555 filt_fifowrite(struct knote *kn, long hint) 556 { 557 struct socket *so; 558 559 so = (struct socket *)kn->kn_hook; 560 kn->kn_data = sbspace(&so->so_snd); 561 if (so->so_state & SS_CANTSENDMORE) { 562 kn->kn_flags |= EV_EOF; 563 return (1); 564 } 565 kn->kn_flags &= ~EV_EOF; 566 return (kn->kn_data >= so->so_snd.sb_lowat); 567 } 568 569 static const struct filterops fiforead_filtops = 570 { 1, NULL, filt_fifordetach, filt_fiforead }; 571 static const struct filterops fifowrite_filtops = 572 { 1, NULL, filt_fifowdetach, filt_fifowrite }; 573 574 /* ARGSUSED */ 575 int 576 fifo_kqfilter(void *v) 577 { 578 struct vop_kqfilter_args /* { 579 struct vnode *a_vp; 580 struct knote *a_kn; 581 } */ *ap = v; 582 struct socket *so; 583 struct sockbuf *sb; 584 585 so = (struct socket *)ap->a_vp->v_fifoinfo->fi_readsock; 586 switch (ap->a_kn->kn_filter) { 587 case EVFILT_READ: 588 ap->a_kn->kn_fop = &fiforead_filtops; 589 sb = &so->so_rcv; 590 break; 591 case EVFILT_WRITE: 592 ap->a_kn->kn_fop = &fifowrite_filtops; 593 sb = &so->so_snd; 594 break; 595 default: 596 return (1); 597 } 598 599 ap->a_kn->kn_hook = so; 600 601 SLIST_INSERT_HEAD(&sb->sb_sel.sel_klist, ap->a_kn, kn_selnext); 602 sb->sb_flags |= SB_KNOTE; 603 return (0); 604 }
Cache object: 8fcf56e095ddca9375d8fdb793ec8590
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