Line data Source code
1 : /* $OpenBSD: fifo_vnops.c,v 1.68 2018/07/30 12:22:14 mpi Exp $ */
2 : /* $NetBSD: fifo_vnops.c,v 1.18 1996/03/16 23:52:42 christos Exp $ */
3 :
4 : /*
5 : * Copyright (c) 1990, 1993
6 : * The Regents of the University of California. All rights reserved.
7 : *
8 : * Redistribution and use in source and binary forms, with or without
9 : * modification, are permitted provided that the following conditions
10 : * are met:
11 : * 1. Redistributions of source code must retain the above copyright
12 : * notice, this list of conditions and the following disclaimer.
13 : * 2. Redistributions in binary form must reproduce the above copyright
14 : * notice, this list of conditions and the following disclaimer in the
15 : * documentation and/or other materials provided with the distribution.
16 : * 3. Neither the name of the University nor the names of its contributors
17 : * may be used to endorse or promote products derived from this software
18 : * without specific prior written permission.
19 : *
20 : * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 : * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 : * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 : * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 : * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 : * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 : * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 : * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 : * SUCH DAMAGE.
31 : *
32 : * @(#)fifo_vnops.c 8.4 (Berkeley) 8/10/94
33 : */
34 :
35 : #include <sys/param.h>
36 : #include <sys/systm.h>
37 : #include <sys/time.h>
38 : #include <sys/namei.h>
39 : #include <sys/vnode.h>
40 : #include <sys/lock.h>
41 : #include <sys/protosw.h>
42 : #include <sys/socket.h>
43 : #include <sys/socketvar.h>
44 : #include <sys/stat.h>
45 : #include <sys/ioctl.h>
46 : #include <sys/fcntl.h>
47 : #include <sys/file.h>
48 : #include <sys/event.h>
49 : #include <sys/errno.h>
50 : #include <sys/malloc.h>
51 : #include <sys/poll.h>
52 : #include <sys/unistd.h>
53 :
54 : #include <miscfs/fifofs/fifo.h>
55 :
56 : /*
57 : * This structure is associated with the FIFO vnode and stores
58 : * the state associated with the FIFO.
59 : */
60 : struct fifoinfo {
61 : struct socket *fi_readsock;
62 : struct socket *fi_writesock;
63 : long fi_readers;
64 : long fi_writers;
65 : };
66 :
67 : struct vops fifo_vops = {
68 : .vop_lookup = vop_generic_lookup,
69 : .vop_create = fifo_badop,
70 : .vop_mknod = fifo_badop,
71 : .vop_open = fifo_open,
72 : .vop_close = fifo_close,
73 : .vop_access = fifo_ebadf,
74 : .vop_getattr = fifo_ebadf,
75 : .vop_setattr = fifo_ebadf,
76 : .vop_read = fifo_read,
77 : .vop_write = fifo_write,
78 : .vop_ioctl = fifo_ioctl,
79 : .vop_poll = fifo_poll,
80 : .vop_kqfilter = fifo_kqfilter,
81 : .vop_revoke = vop_generic_revoke,
82 : .vop_fsync = nullop,
83 : .vop_remove = fifo_badop,
84 : .vop_link = fifo_badop,
85 : .vop_rename = fifo_badop,
86 : .vop_mkdir = fifo_badop,
87 : .vop_rmdir = fifo_badop,
88 : .vop_symlink = fifo_badop,
89 : .vop_readdir = fifo_badop,
90 : .vop_readlink = fifo_badop,
91 : .vop_abortop = fifo_badop,
92 : .vop_inactive = fifo_inactive,
93 : .vop_reclaim = fifo_reclaim,
94 : .vop_lock = vop_generic_lock,
95 : .vop_unlock = vop_generic_unlock,
96 : .vop_bmap = vop_generic_bmap,
97 : .vop_strategy = fifo_badop,
98 : .vop_print = fifo_print,
99 : .vop_islocked = vop_generic_islocked,
100 : .vop_pathconf = fifo_pathconf,
101 : .vop_advlock = fifo_advlock,
102 : .vop_bwrite = nullop
103 : };
104 :
105 : void filt_fifordetach(struct knote *kn);
106 : int filt_fiforead(struct knote *kn, long hint);
107 : void filt_fifowdetach(struct knote *kn);
108 : int filt_fifowrite(struct knote *kn, long hint);
109 :
110 : struct filterops fiforead_filtops =
111 : { 1, NULL, filt_fifordetach, filt_fiforead };
112 : struct filterops fifowrite_filtops =
113 : { 1, NULL, filt_fifowdetach, filt_fifowrite };
114 :
115 : /*
116 : * Open called to set up a new instance of a fifo or
117 : * to find an active instance of a fifo.
118 : */
119 : /* ARGSUSED */
120 : int
121 0 : fifo_open(void *v)
122 : {
123 0 : struct vop_open_args *ap = v;
124 0 : struct vnode *vp = ap->a_vp;
125 : struct fifoinfo *fip;
126 0 : struct socket *rso, *wso;
127 : int s, error;
128 :
129 0 : if ((fip = vp->v_fifoinfo) == NULL) {
130 0 : fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK);
131 0 : vp->v_fifoinfo = fip;
132 0 : if ((error = socreate(AF_UNIX, &rso, SOCK_STREAM, 0)) != 0) {
133 0 : free(fip, M_VNODE, sizeof *fip);
134 0 : vp->v_fifoinfo = NULL;
135 0 : return (error);
136 : }
137 0 : fip->fi_readsock = rso;
138 0 : if ((error = socreate(AF_UNIX, &wso, SOCK_STREAM, 0)) != 0) {
139 0 : (void)soclose(rso, 0);
140 0 : free(fip, M_VNODE, sizeof *fip);
141 0 : vp->v_fifoinfo = NULL;
142 0 : return (error);
143 : }
144 0 : fip->fi_writesock = wso;
145 0 : if ((error = soconnect2(wso, rso)) != 0) {
146 0 : (void)soclose(wso, 0);
147 0 : (void)soclose(rso, 0);
148 0 : free(fip, M_VNODE, sizeof *fip);
149 0 : vp->v_fifoinfo = NULL;
150 0 : return (error);
151 : }
152 0 : fip->fi_readers = fip->fi_writers = 0;
153 0 : s = solock(wso);
154 0 : wso->so_state |= SS_CANTSENDMORE;
155 0 : wso->so_snd.sb_lowat = PIPE_BUF;
156 0 : } else {
157 0 : rso = fip->fi_readsock;
158 0 : wso = fip->fi_writesock;
159 0 : s = solock(wso);
160 : }
161 0 : if (ap->a_mode & FREAD) {
162 0 : fip->fi_readers++;
163 0 : if (fip->fi_readers == 1) {
164 0 : wso->so_state &= ~SS_CANTSENDMORE;
165 0 : if (fip->fi_writers > 0)
166 0 : wakeup(&fip->fi_writers);
167 : }
168 : }
169 0 : if (ap->a_mode & FWRITE) {
170 0 : fip->fi_writers++;
171 0 : if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
172 : error = ENXIO;
173 0 : sounlock(wso, s);
174 0 : goto bad;
175 : }
176 0 : if (fip->fi_writers == 1) {
177 0 : rso->so_state &= ~(SS_CANTRCVMORE|SS_ISDISCONNECTED);
178 0 : if (fip->fi_readers > 0)
179 0 : wakeup(&fip->fi_readers);
180 : }
181 : }
182 0 : sounlock(wso, s);
183 0 : if ((ap->a_mode & O_NONBLOCK) == 0) {
184 0 : if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
185 0 : VOP_UNLOCK(vp);
186 0 : error = tsleep(&fip->fi_readers,
187 : PCATCH | PSOCK, "fifor", 0);
188 0 : vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
189 0 : if (error)
190 : goto bad;
191 : }
192 0 : if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
193 0 : VOP_UNLOCK(vp);
194 0 : error = tsleep(&fip->fi_writers,
195 : PCATCH | PSOCK, "fifow", 0);
196 0 : vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
197 0 : if (error)
198 : goto bad;
199 : }
200 : }
201 0 : return (0);
202 : bad:
203 0 : VOP_CLOSE(vp, ap->a_mode, ap->a_cred, ap->a_p);
204 0 : return (error);
205 0 : }
206 :
207 : /*
208 : * Vnode op for read
209 : */
210 : /* ARGSUSED */
211 : int
212 0 : fifo_read(void *v)
213 : {
214 0 : struct vop_read_args *ap = v;
215 0 : struct uio *uio = ap->a_uio;
216 0 : struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
217 0 : int error, flags = 0;
218 :
219 : #ifdef DIAGNOSTIC
220 0 : if (uio->uio_rw != UIO_READ)
221 0 : panic("fifo_read mode");
222 : #endif
223 0 : if (uio->uio_resid == 0)
224 0 : return (0);
225 0 : if (ap->a_ioflag & IO_NDELAY)
226 0 : flags |= MSG_DONTWAIT;
227 0 : VOP_UNLOCK(ap->a_vp);
228 0 : error = soreceive(rso, NULL, uio, NULL, NULL, &flags, 0);
229 0 : vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
230 0 : if (ap->a_ioflag & IO_NDELAY) {
231 0 : if (error == EWOULDBLOCK &&
232 0 : ap->a_vp->v_fifoinfo->fi_writers == 0)
233 0 : error = 0;
234 : }
235 0 : return (error);
236 0 : }
237 :
238 : /*
239 : * Vnode op for write
240 : */
241 : /* ARGSUSED */
242 : int
243 0 : fifo_write(void *v)
244 : {
245 0 : struct vop_write_args *ap = v;
246 0 : struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
247 : int error, flags = 0;
248 :
249 : #ifdef DIAGNOSTIC
250 0 : if (ap->a_uio->uio_rw != UIO_WRITE)
251 0 : panic("fifo_write mode");
252 : #endif
253 0 : if (ap->a_ioflag & IO_NDELAY)
254 0 : flags |= MSG_DONTWAIT;
255 0 : VOP_UNLOCK(ap->a_vp);
256 0 : error = sosend(wso, NULL, ap->a_uio, NULL, NULL, flags);
257 0 : vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
258 0 : return (error);
259 : }
260 :
261 : /*
262 : * Device ioctl operation.
263 : */
264 : /* ARGSUSED */
265 : int
266 0 : fifo_ioctl(void *v)
267 : {
268 0 : struct vop_ioctl_args *ap = v;
269 0 : struct file filetmp;
270 : int error;
271 :
272 0 : if (ap->a_command == FIONBIO)
273 0 : return (0);
274 0 : if (ap->a_fflag & FREAD) {
275 0 : filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock;
276 0 : error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_p);
277 0 : if (error)
278 0 : return (error);
279 : }
280 0 : if (ap->a_fflag & FWRITE) {
281 0 : filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock;
282 0 : error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_p);
283 0 : if (error)
284 0 : return (error);
285 : }
286 0 : return (0);
287 0 : }
288 :
289 : /* ARGSUSED */
290 : int
291 0 : fifo_poll(void *v)
292 : {
293 0 : struct vop_poll_args *ap = v;
294 0 : struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
295 0 : struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
296 : int events = 0;
297 : int revents = 0;
298 : int s;
299 :
300 : /*
301 : * FIFOs don't support out-of-band or high priority data.
302 : */
303 0 : s = solock(rso);
304 0 : if (ap->a_fflag & FREAD)
305 0 : events |= ap->a_events & (POLLIN | POLLRDNORM);
306 0 : if (ap->a_fflag & FWRITE)
307 0 : events |= ap->a_events & (POLLOUT | POLLWRNORM);
308 :
309 0 : if (events & (POLLIN | POLLRDNORM)) {
310 0 : if (soreadable(rso))
311 0 : revents |= events & (POLLIN | POLLRDNORM);
312 : }
313 : /* NOTE: POLLHUP and POLLOUT/POLLWRNORM are mutually exclusive */
314 0 : if ((rso->so_state & SS_ISDISCONNECTED) && !(ap->a_events & POLL_NOHUP)) {
315 0 : revents |= POLLHUP;
316 0 : } else if (events & (POLLOUT | POLLWRNORM)) {
317 0 : if (sowriteable(wso))
318 0 : revents |= events & (POLLOUT | POLLWRNORM);
319 : }
320 0 : if (revents == 0) {
321 : /* We want to return POLLHUP even if no valid events set. */
322 0 : if (events == 0 && !(ap->a_events & POLL_NOHUP))
323 0 : events = POLLIN;
324 0 : if (events & (POLLIN | POLLRDNORM)) {
325 0 : selrecord(ap->a_p, &rso->so_rcv.sb_sel);
326 0 : rso->so_rcv.sb_flags |= SB_SEL;
327 0 : }
328 0 : if (events & (POLLOUT | POLLWRNORM)) {
329 0 : selrecord(ap->a_p, &wso->so_snd.sb_sel);
330 0 : wso->so_snd.sb_flags |= SB_SEL;
331 0 : }
332 : }
333 0 : sounlock(rso, s);
334 0 : return (revents);
335 : }
336 :
337 : int
338 0 : fifo_inactive(void *v)
339 : {
340 0 : struct vop_inactive_args *ap = v;
341 :
342 0 : VOP_UNLOCK(ap->a_vp);
343 0 : return (0);
344 : }
345 :
346 :
347 : /*
348 : * Device close routine
349 : */
350 : /* ARGSUSED */
351 : int
352 0 : fifo_close(void *v)
353 : {
354 0 : struct vop_close_args *ap = v;
355 0 : struct vnode *vp = ap->a_vp;
356 0 : struct fifoinfo *fip = vp->v_fifoinfo;
357 : int s, error1 = 0, error2 = 0;
358 :
359 0 : if (fip == NULL)
360 0 : return (0);
361 :
362 0 : if (ap->a_fflag & FREAD) {
363 0 : if (--fip->fi_readers == 0) {
364 0 : struct socket *wso = fip->fi_writesock;
365 :
366 0 : s = solock(wso);
367 0 : socantsendmore(wso);
368 0 : sounlock(wso, s);
369 0 : }
370 : }
371 0 : if (ap->a_fflag & FWRITE) {
372 0 : if (--fip->fi_writers == 0) {
373 0 : struct socket *rso = fip->fi_readsock;
374 :
375 0 : s = solock(rso);
376 : /* SS_ISDISCONNECTED will result in POLLHUP */
377 0 : rso->so_state |= SS_ISDISCONNECTED;
378 0 : socantrcvmore(rso);
379 0 : sounlock(rso, s);
380 0 : }
381 : }
382 0 : if (fip->fi_readers == 0 && fip->fi_writers == 0) {
383 0 : error1 = soclose(fip->fi_readsock, 0);
384 0 : error2 = soclose(fip->fi_writesock, 0);
385 0 : free(fip, M_VNODE, sizeof *fip);
386 0 : vp->v_fifoinfo = NULL;
387 0 : }
388 0 : return (error1 ? error1 : error2);
389 0 : }
390 :
391 : int
392 0 : fifo_reclaim(void *v)
393 : {
394 0 : struct vop_reclaim_args *ap = v;
395 0 : struct vnode *vp = ap->a_vp;
396 0 : struct fifoinfo *fip = vp->v_fifoinfo;
397 :
398 0 : if (fip == NULL)
399 0 : return (0);
400 :
401 0 : soclose(fip->fi_readsock, 0);
402 0 : soclose(fip->fi_writesock, 0);
403 0 : free(fip, M_VNODE, sizeof *fip);
404 0 : vp->v_fifoinfo = NULL;
405 :
406 0 : return (0);
407 0 : }
408 :
409 : /*
410 : * Print out the contents of a fifo vnode.
411 : */
412 : int
413 0 : fifo_print(void *v)
414 : {
415 0 : struct vop_print_args *ap = v;
416 :
417 0 : printf("tag VT_NON");
418 0 : fifo_printinfo(ap->a_vp);
419 0 : printf("\n");
420 0 : return 0;
421 : }
422 :
423 : /*
424 : * Print out internal contents of a fifo vnode.
425 : */
426 : void
427 0 : fifo_printinfo(struct vnode *vp)
428 : {
429 0 : struct fifoinfo *fip = vp->v_fifoinfo;
430 :
431 0 : printf(", fifo with %ld readers and %ld writers",
432 0 : fip->fi_readers, fip->fi_writers);
433 0 : }
434 :
435 : /*
436 : * Return POSIX pathconf information applicable to fifo's.
437 : */
438 : int
439 0 : fifo_pathconf(void *v)
440 : {
441 0 : struct vop_pathconf_args *ap = v;
442 : int error = 0;
443 :
444 0 : switch (ap->a_name) {
445 : case _PC_LINK_MAX:
446 0 : *ap->a_retval = LINK_MAX;
447 0 : break;
448 : case _PC_CHOWN_RESTRICTED:
449 0 : *ap->a_retval = 1;
450 0 : break;
451 : case _PC_TIMESTAMP_RESOLUTION:
452 0 : *ap->a_retval = 1;
453 0 : break;
454 : default:
455 : error = EINVAL;
456 0 : break;
457 : }
458 :
459 0 : return (error);
460 : }
461 :
462 : /*
463 : * Fifo failed operation
464 : */
465 : /*ARGSUSED*/
466 : int
467 0 : fifo_ebadf(void *v)
468 : {
469 :
470 0 : return (EBADF);
471 : }
472 :
473 : /*
474 : * Fifo advisory byte-level locks.
475 : */
476 : /* ARGSUSED */
477 : int
478 0 : fifo_advlock(void *v)
479 : {
480 0 : return (EOPNOTSUPP);
481 : }
482 :
483 : /*
484 : * Fifo bad operation
485 : */
486 : /*ARGSUSED*/
487 : int
488 0 : fifo_badop(void *v)
489 : {
490 :
491 0 : panic("fifo_badop called");
492 : /* NOTREACHED */
493 : return(0);
494 : }
495 :
496 :
497 : int
498 0 : fifo_kqfilter(void *v)
499 : {
500 0 : struct vop_kqfilter_args *ap = v;
501 0 : struct socket *so = (struct socket *)ap->a_vp->v_fifoinfo->fi_readsock;
502 : struct sockbuf *sb;
503 :
504 0 : switch (ap->a_kn->kn_filter) {
505 : case EVFILT_READ:
506 0 : ap->a_kn->kn_fop = &fiforead_filtops;
507 0 : sb = &so->so_rcv;
508 0 : break;
509 : case EVFILT_WRITE:
510 0 : ap->a_kn->kn_fop = &fifowrite_filtops;
511 0 : sb = &so->so_snd;
512 0 : break;
513 : default:
514 0 : return (EINVAL);
515 : }
516 :
517 0 : ap->a_kn->kn_hook = so;
518 :
519 0 : SLIST_INSERT_HEAD(&sb->sb_sel.si_note, ap->a_kn, kn_selnext);
520 0 : sb->sb_flagsintr |= SB_KNOTE;
521 :
522 0 : return (0);
523 0 : }
524 :
525 : void
526 0 : filt_fifordetach(struct knote *kn)
527 : {
528 0 : struct socket *so = (struct socket *)kn->kn_hook;
529 :
530 0 : SLIST_REMOVE(&so->so_rcv.sb_sel.si_note, kn, knote, kn_selnext);
531 0 : if (SLIST_EMPTY(&so->so_rcv.sb_sel.si_note))
532 0 : so->so_rcv.sb_flagsintr &= ~SB_KNOTE;
533 0 : }
534 :
535 : int
536 0 : filt_fiforead(struct knote *kn, long hint)
537 : {
538 0 : struct socket *so = (struct socket *)kn->kn_hook;
539 : int rv;
540 :
541 0 : kn->kn_data = so->so_rcv.sb_cc;
542 0 : if (so->so_state & SS_CANTRCVMORE) {
543 0 : kn->kn_flags |= EV_EOF;
544 : rv = 1;
545 0 : } else {
546 0 : kn->kn_flags &= ~EV_EOF;
547 0 : rv = (kn->kn_data > 0);
548 : }
549 :
550 0 : return (rv);
551 : }
552 :
553 : void
554 0 : filt_fifowdetach(struct knote *kn)
555 : {
556 0 : struct socket *so = (struct socket *)kn->kn_hook;
557 :
558 0 : SLIST_REMOVE(&so->so_snd.sb_sel.si_note, kn, knote, kn_selnext);
559 0 : if (SLIST_EMPTY(&so->so_snd.sb_sel.si_note))
560 0 : so->so_snd.sb_flagsintr &= ~SB_KNOTE;
561 0 : }
562 :
563 : int
564 0 : filt_fifowrite(struct knote *kn, long hint)
565 : {
566 0 : struct socket *so = (struct socket *)kn->kn_hook;
567 : int rv;
568 :
569 0 : kn->kn_data = sbspace(so, &so->so_snd);
570 0 : if (so->so_state & SS_CANTSENDMORE) {
571 0 : kn->kn_flags |= EV_EOF;
572 : rv = 1;
573 0 : } else {
574 0 : kn->kn_flags &= ~EV_EOF;
575 0 : rv = (kn->kn_data >= so->so_snd.sb_lowat);
576 : }
577 :
578 0 : return (rv);
579 : }
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