xref: /netbsd/sys/miscfs/fifofs/fifo_vnops.c (revision c4a72b64) 
1 /*	$NetBSD: fifo_vnops.c,v 1.37 2002/11/26 19:01:55 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. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)fifo_vnops.c	8.10 (Berkeley) 5/27/95
36  */
37 
38 #include <sys/cdefs.h>
39 __KERNEL_RCSID(0, "$NetBSD: fifo_vnops.c,v 1.37 2002/11/26 19:01:55 christos Exp $");
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/proc.h>
44 #include <sys/time.h>
45 #include <sys/namei.h>
46 #include <sys/vnode.h>
47 #include <sys/socket.h>
48 #include <sys/socketvar.h>
49 #include <sys/stat.h>
50 #include <sys/ioctl.h>
51 #include <sys/file.h>
52 #include <sys/errno.h>
53 #include <sys/malloc.h>
54 #include <sys/un.h>
55 #include <sys/poll.h>
56 #include <sys/event.h>
57 
58 #include <miscfs/fifofs/fifo.h>
59 #include <miscfs/genfs/genfs.h>
60 
61 /*
62  * This structure is associated with the FIFO vnode and stores
63  * the state associated with the FIFO.
64  */
65 struct fifoinfo {
66 	struct socket	*fi_readsock;
67 	struct socket	*fi_writesock;
68 	long		fi_opencount;
69 	long		fi_readers;
70 	long		fi_writers;
71 };
72 
73 int (**fifo_vnodeop_p) __P((void *));
74 const struct vnodeopv_entry_desc fifo_vnodeop_entries[] = {
75 	{ &vop_default_desc, vn_default_error },
76 	{ &vop_lookup_desc, fifo_lookup },		/* lookup */
77 	{ &vop_create_desc, fifo_create },		/* create */
78 	{ &vop_mknod_desc, fifo_mknod },		/* mknod */
79 	{ &vop_open_desc, fifo_open },			/* open */
80 	{ &vop_close_desc, fifo_close },		/* close */
81 	{ &vop_access_desc, fifo_access },		/* access */
82 	{ &vop_getattr_desc, fifo_getattr },		/* getattr */
83 	{ &vop_setattr_desc, fifo_setattr },		/* setattr */
84 	{ &vop_read_desc, fifo_read },			/* read */
85 	{ &vop_write_desc, fifo_write },		/* write */
86 	{ &vop_lease_desc, fifo_lease_check },		/* lease */
87 	{ &vop_ioctl_desc, fifo_ioctl },		/* ioctl */
88 	{ &vop_poll_desc, fifo_poll },			/* poll */
89 	{ &vop_kqfilter_desc, fifo_kqfilter },		/* kqfilter */
90 	{ &vop_revoke_desc, fifo_revoke },		/* revoke */
91 	{ &vop_mmap_desc, fifo_mmap },			/* mmap */
92 	{ &vop_fsync_desc, fifo_fsync },		/* fsync */
93 	{ &vop_seek_desc, fifo_seek },			/* seek */
94 	{ &vop_remove_desc, fifo_remove },		/* remove */
95 	{ &vop_link_desc, fifo_link },			/* link */
96 	{ &vop_rename_desc, fifo_rename },		/* rename */
97 	{ &vop_mkdir_desc, fifo_mkdir },		/* mkdir */
98 	{ &vop_rmdir_desc, fifo_rmdir },		/* rmdir */
99 	{ &vop_symlink_desc, fifo_symlink },		/* symlink */
100 	{ &vop_readdir_desc, fifo_readdir },		/* readdir */
101 	{ &vop_readlink_desc, fifo_readlink },		/* readlink */
102 	{ &vop_abortop_desc, fifo_abortop },		/* abortop */
103 	{ &vop_inactive_desc, fifo_inactive },		/* inactive */
104 	{ &vop_reclaim_desc, fifo_reclaim },		/* reclaim */
105 	{ &vop_lock_desc, fifo_lock },			/* lock */
106 	{ &vop_unlock_desc, fifo_unlock },		/* unlock */
107 	{ &vop_bmap_desc, fifo_bmap },			/* bmap */
108 	{ &vop_strategy_desc, fifo_strategy },		/* strategy */
109 	{ &vop_print_desc, fifo_print },		/* print */
110 	{ &vop_islocked_desc, fifo_islocked },		/* islocked */
111 	{ &vop_pathconf_desc, fifo_pathconf },		/* pathconf */
112 	{ &vop_advlock_desc, fifo_advlock },		/* advlock */
113 	{ &vop_blkatoff_desc, fifo_blkatoff },		/* blkatoff */
114 	{ &vop_valloc_desc, fifo_valloc },		/* valloc */
115 	{ &vop_vfree_desc, fifo_vfree },		/* vfree */
116 	{ &vop_truncate_desc, fifo_truncate },		/* truncate */
117 	{ &vop_update_desc, fifo_update },		/* update */
118 	{ &vop_bwrite_desc, fifo_bwrite },		/* bwrite */
119 	{ &vop_putpages_desc, fifo_putpages }, 		/* putpages */
120 	{ (struct vnodeop_desc*)NULL, (int(*) __P((void *)))NULL }
121 };
122 const struct vnodeopv_desc fifo_vnodeop_opv_desc =
123 	{ &fifo_vnodeop_p, fifo_vnodeop_entries };
124 
125 /*
126  * Trivial lookup routine that always fails.
127  */
128 /* ARGSUSED */
129 int
130 fifo_lookup(void *v)
131 {
132 	struct vop_lookup_args /* {
133 		struct vnode		*a_dvp;
134 		struct vnode		**a_vpp;
135 		struct componentname	*a_cnp;
136 	} */ *ap = v;
137 
138 	*ap->a_vpp = NULL;
139 	return (ENOTDIR);
140 }
141 
142 /*
143  * Open called to set up a new instance of a fifo or
144  * to find an active instance of a fifo.
145  */
146 /* ARGSUSED */
147 int
148 fifo_open(void *v)
149 {
150 	struct vop_open_args /* {
151 		struct vnode	*a_vp;
152 		int		a_mode;
153 		struct ucred	*a_cred;
154 		struct proc	*a_p;
155 	} */ *ap = v;
156 	struct vnode	*vp;
157 	struct fifoinfo	*fip;
158 	struct proc	*p;
159 	struct socket	*rso, *wso;
160 	int		error;
161 	static const char openstr[] = "fifo";
162 
163 	vp = ap->a_vp;
164 	p = ap->a_p;
165 
166 	if ((fip = vp->v_fifoinfo) == NULL) {
167 		MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK);
168 		vp->v_fifoinfo = fip;
169 		if ((error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0)) != 0) {
170 			free(fip, M_VNODE);
171 			vp->v_fifoinfo = NULL;
172 			return (error);
173 		}
174 		fip->fi_readsock = rso;
175 		if ((error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0)) != 0) {
176 			(void)soclose(rso);
177 			free(fip, M_VNODE);
178 			vp->v_fifoinfo = NULL;
179 			return (error);
180 		}
181 		fip->fi_writesock = wso;
182 		if ((error = unp_connect2(wso, rso)) != 0) {
183 			(void)soclose(wso);
184 			(void)soclose(rso);
185 			free(fip, M_VNODE);
186 			vp->v_fifoinfo = NULL;
187 			return (error);
188 		}
189 		fip->fi_readers = fip->fi_writers = 0;
190 		fip->fi_opencount = 0;
191 		wso->so_state |= SS_CANTRCVMORE;
192 		rso->so_state |= SS_CANTSENDMORE;
193 	}
194 	fip->fi_opencount++;
195 	if (ap->a_mode & FREAD) {
196 		if (fip->fi_readers++ == 0) {
197 			fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
198 			if (fip->fi_writers > 0)
199 				wakeup((caddr_t)&fip->fi_writers);
200 		}
201 	}
202 	if (ap->a_mode & FWRITE) {
203 		if (fip->fi_writers++ == 0) {
204 			fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
205 			if (fip->fi_readers > 0)
206 				wakeup((caddr_t)&fip->fi_readers);
207 		}
208 	}
209 	if (ap->a_mode & FREAD) {
210 		if (ap->a_mode & O_NONBLOCK) {
211 		} else {
212 			while (fip->fi_writers == 0) {
213 				VOP_UNLOCK(vp, 0);
214 				error = tsleep((caddr_t)&fip->fi_readers,
215 				    PCATCH | PSOCK, openstr, 0);
216 				vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
217 				if (error)
218 					goto bad;
219 			}
220 		}
221 	}
222 	if (ap->a_mode & FWRITE) {
223 		if (ap->a_mode & O_NONBLOCK) {
224 			if (fip->fi_readers == 0) {
225 				error = ENXIO;
226 				goto bad;
227 			}
228 		} else {
229 			while (fip->fi_readers == 0) {
230 				VOP_UNLOCK(vp, 0);
231 				error = tsleep((caddr_t)&fip->fi_writers,
232 				    PCATCH | PSOCK, openstr, 0);
233 				vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
234 				if (error)
235 					goto bad;
236 			}
237 		}
238 	}
239 	return (0);
240  bad:
241 	VOP_CLOSE(vp, ap->a_mode, ap->a_cred, p);
242 	return (error);
243 }
244 
245 /*
246  * Vnode op for read
247  */
248 /* ARGSUSED */
249 int
250 fifo_read(void *v)
251 {
252 	struct vop_read_args /* {
253 		struct vnode	*a_vp;
254 		struct uio	*a_uio;
255 		int		a_ioflag;
256 		struct ucred	*a_cred;
257 	} */ *ap = v;
258 	struct uio	*uio;
259 	struct socket	*rso;
260 	int		error;
261 	size_t		startresid;
262 
263 	uio = ap->a_uio;
264 	rso = ap->a_vp->v_fifoinfo->fi_readsock;
265 #ifdef DIAGNOSTIC
266 	if (uio->uio_rw != UIO_READ)
267 		panic("fifo_read mode");
268 #endif
269 	if (uio->uio_resid == 0)
270 		return (0);
271 	if (ap->a_ioflag & IO_NDELAY)
272 		rso->so_state |= SS_NBIO;
273 	startresid = uio->uio_resid;
274 	VOP_UNLOCK(ap->a_vp, 0);
275 	error = (*rso->so_receive)(rso, (struct mbuf **)0, uio,
276 	    (struct mbuf **)0, (struct mbuf **)0, (int *)0);
277 	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
278 	/*
279 	 * Clear EOF indication after first such return.
280 	 */
281 	if (uio->uio_resid == startresid)
282 		rso->so_state &= ~SS_CANTRCVMORE;
283 	if (ap->a_ioflag & IO_NDELAY) {
284 		rso->so_state &= ~SS_NBIO;
285 		if (error == EWOULDBLOCK &&
286 		    ap->a_vp->v_fifoinfo->fi_writers == 0)
287 			error = 0;
288 	}
289 	return (error);
290 }
291 
292 /*
293  * Vnode op for write
294  */
295 /* ARGSUSED */
296 int
297 fifo_write(void *v)
298 {
299 	struct vop_write_args /* {
300 		struct vnode	*a_vp;
301 		struct uio	*a_uio;
302 		int		a_ioflag;
303 		struct ucred	*a_cred;
304 	} */ *ap = v;
305 	struct socket	*wso;
306 	int		error;
307 
308 	wso = ap->a_vp->v_fifoinfo->fi_writesock;
309 #ifdef DIAGNOSTIC
310 	if (ap->a_uio->uio_rw != UIO_WRITE)
311 		panic("fifo_write mode");
312 #endif
313 	if (ap->a_ioflag & IO_NDELAY)
314 		wso->so_state |= SS_NBIO;
315 	VOP_UNLOCK(ap->a_vp, 0);
316 	error = (*wso->so_send)(wso, (struct mbuf *)0, ap->a_uio, 0,
317 	    (struct mbuf *)0, 0);
318 	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
319 	if (ap->a_ioflag & IO_NDELAY)
320 		wso->so_state &= ~SS_NBIO;
321 	return (error);
322 }
323 
324 /*
325  * Device ioctl operation.
326  */
327 /* ARGSUSED */
328 int
329 fifo_ioctl(void *v)
330 {
331 	struct vop_ioctl_args /* {
332 		struct vnode	*a_vp;
333 		u_long		a_command;
334 		caddr_t		a_data;
335 		int		a_fflag;
336 		struct ucred	*a_cred;
337 		struct proc	*a_p;
338 	} */ *ap = v;
339 	struct file	filetmp;
340 	int		error;
341 
342 	if (ap->a_command == FIONBIO)
343 		return (0);
344 	if (ap->a_fflag & FREAD) {
345 		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
346 		error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_p);
347 		if (error)
348 			return (error);
349 	}
350 	if (ap->a_fflag & FWRITE) {
351 		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
352 		error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_p);
353 		if (error)
354 			return (error);
355 	}
356 	return (0);
357 }
358 
359 /* ARGSUSED */
360 int
361 fifo_poll(void *v)
362 {
363 	struct vop_poll_args /* {
364 		struct vnode	*a_vp;
365 		int		a_events;
366 		struct proc	*a_p;
367 	} */ *ap = v;
368 	struct file	filetmp;
369 	int		revents;
370 
371 	revents = 0;
372 	if (ap->a_events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) {
373 		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
374 		if (filetmp.f_data)
375 			revents |= soo_poll(&filetmp, ap->a_events, ap->a_p);
376 	}
377 	if (ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
378 		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
379 		if (filetmp.f_data)
380 			revents |= soo_poll(&filetmp, ap->a_events, ap->a_p);
381 	}
382 
383 	return (revents);
384 }
385 
386 int
387 fifo_inactive(void *v)
388 {
389 	struct vop_inactive_args /* {
390 		struct vnode	*a_vp;
391 		struct proc	*a_p;
392 	} */ *ap = v;
393 
394 	VOP_UNLOCK(ap->a_vp, 0);
395 	return (0);
396 }
397 
398 /*
399  * This is a noop, simply returning what one has been given.
400  */
401 int
402 fifo_bmap(void *v)
403 {
404 	struct vop_bmap_args /* {
405 		struct vnode	*a_vp;
406 		daddr_t		a_bn;
407 		struct vnode	**a_vpp;
408 		daddr_t		*a_bnp;
409 		int		*a_runp;
410 	} */ *ap = v;
411 
412 	if (ap->a_vpp != NULL)
413 		*ap->a_vpp = ap->a_vp;
414 	if (ap->a_bnp != NULL)
415 		*ap->a_bnp = ap->a_bn;
416 	if (ap->a_runp != NULL)
417 		*ap->a_runp = 0;
418 	return (0);
419 }
420 
421 /*
422  * Device close routine
423  */
424 /* ARGSUSED */
425 int
426 fifo_close(void *v)
427 {
428 	struct vop_close_args /* {
429 		struct vnode	*a_vp;
430 		int		a_fflag;
431 		struct ucred	*a_cred;
432 		struct proc	*a_p;
433 	} */ *ap = v;
434 	struct vnode	*vp;
435 	struct fifoinfo	*fip;
436 
437 	vp = ap->a_vp;
438 	fip = vp->v_fifoinfo;
439 	if (ap->a_fflag & FREAD) {
440 		if (--fip->fi_readers == 0)
441 			socantsendmore(fip->fi_writesock);
442 	}
443 	if (ap->a_fflag & FWRITE) {
444 		if (--fip->fi_writers == 0)
445 			socantrcvmore(fip->fi_readsock);
446 	}
447 	if (--fip->fi_opencount == 0) {
448 		(void) soclose(fip->fi_readsock);
449 		(void) soclose(fip->fi_writesock);
450 		FREE(fip, M_VNODE);
451 		vp->v_fifoinfo = NULL;
452 	}
453 	return (0);
454 }
455 
456 /*
457  * Print out the contents of a fifo vnode.
458  */
459 int
460 fifo_print(void *v)
461 {
462 	struct vop_print_args /* {
463 		struct vnode	*a_vp;
464 	} */ *ap = v;
465 
466 	printf("tag VT_NON");
467 	fifo_printinfo(ap->a_vp);
468 	printf("\n");
469 	return 0;
470 }
471 
472 /*
473  * Print out internal contents of a fifo vnode.
474  */
475 void
476 fifo_printinfo(struct vnode *vp)
477 {
478 	struct fifoinfo	*fip;
479 
480 	fip = vp->v_fifoinfo;
481 	printf(", fifo with %ld readers and %ld writers",
482 	    fip->fi_readers, fip->fi_writers);
483 }
484 
485 /*
486  * Return POSIX pathconf information applicable to fifo's.
487  */
488 int
489 fifo_pathconf(void *v)
490 {
491 	struct vop_pathconf_args /* {
492 		struct vnode	*a_vp;
493 		int		a_name;
494 		register_t	*a_retval;
495 	} */ *ap = v;
496 
497 	switch (ap->a_name) {
498 	case _PC_LINK_MAX:
499 		*ap->a_retval = LINK_MAX;
500 		return (0);
501 	case _PC_PIPE_BUF:
502 		*ap->a_retval = PIPE_BUF;
503 		return (0);
504 	case _PC_CHOWN_RESTRICTED:
505 		*ap->a_retval = 1;
506 		return (0);
507 	case _PC_SYNC_IO:
508 		*ap->a_retval = 1;
509 		return (0);
510 	default:
511 		return (EINVAL);
512 	}
513 	/* NOTREACHED */
514 }
515 
516 static void
517 filt_fifordetach(struct knote *kn)
518 {
519 	struct socket *so;
520 
521 	so = (struct socket *)kn->kn_hook;
522 	SLIST_REMOVE(&so->so_rcv.sb_sel.sel_klist, kn, knote, kn_selnext);
523 	if (SLIST_EMPTY(&so->so_rcv.sb_sel.sel_klist))
524 		so->so_rcv.sb_flags &= ~SB_KNOTE;
525 }
526 
527 static int
528 filt_fiforead(struct knote *kn, long hint)
529 {
530 	struct socket *so;
531 
532 	so = (struct socket *)kn->kn_hook;
533 	kn->kn_data = so->so_rcv.sb_cc;
534 	if (so->so_state & SS_CANTRCVMORE) {
535 		kn->kn_flags |= EV_EOF;
536 		return (1);
537 	}
538 	kn->kn_flags &= ~EV_EOF;
539 	return (kn->kn_data > 0);
540 }
541 
542 static void
543 filt_fifowdetach(struct knote *kn)
544 {
545 	struct socket *so;
546 
547 	so = (struct socket *)kn->kn_hook;
548 	SLIST_REMOVE(&so->so_snd.sb_sel.sel_klist, kn, knote, kn_selnext);
549 	if (SLIST_EMPTY(&so->so_snd.sb_sel.sel_klist))
550 		so->so_snd.sb_flags &= ~SB_KNOTE;
551 }
552 
553 static int
554 filt_fifowrite(struct knote *kn, long hint)
555 {
556 	struct socket *so;
557 
558 	so = (struct socket *)kn->kn_hook;
559 	kn->kn_data = sbspace(&so->so_snd);
560 	if (so->so_state & SS_CANTSENDMORE) {
561 		kn->kn_flags |= EV_EOF;
562 		return (1);
563 	}
564 	kn->kn_flags &= ~EV_EOF;
565 	return (kn->kn_data >= so->so_snd.sb_lowat);
566 }
567 
568 static const struct filterops fiforead_filtops =
569 	{ 1, NULL, filt_fifordetach, filt_fiforead };
570 static const struct filterops fifowrite_filtops =
571 	{ 1, NULL, filt_fifowdetach, filt_fifowrite };
572 
573 /* ARGSUSED */
574 int
575 fifo_kqfilter(void *v)
576 {
577 	struct vop_kqfilter_args /* {
578 		struct vnode *a_vp;
579 		struct knote *a_kn;
580 	} */ *ap = v;
581 	struct socket	*so;
582 	struct sockbuf	*sb;
583 
584 	so = (struct socket *)ap->a_vp->v_fifoinfo->fi_readsock;
585 	switch (ap->a_kn->kn_filter) {
586 	case EVFILT_READ:
587 		ap->a_kn->kn_fop = &fiforead_filtops;
588 		sb = &so->so_rcv;
589 		break;
590 	case EVFILT_WRITE:
591 		ap->a_kn->kn_fop = &fifowrite_filtops;
592 		sb = &so->so_snd;
593 		break;
594 	default:
595 		return (1);
596 	}
597 
598 	ap->a_kn->kn_hook = so;
599 
600 	SLIST_INSERT_HEAD(&sb->sb_sel.sel_klist, ap->a_kn, kn_selnext);
601 	sb->sb_flags |= SB_KNOTE;
602 	return (0);
603 }
604