2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 2007-2009 Google Inc.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following disclaimer
15 * in the documentation and/or other materials provided with the
17 * * Neither the name of Google Inc. nor the names of its
18 * contributors may be used to endorse or promote products derived from
19 * this software without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 * Copyright (C) 2005 Csaba Henk.
34 * All rights reserved.
36 * Copyright (c) 2019 The FreeBSD Foundation
38 * Portions of this software were developed by BFF Storage Systems, LLC under
39 * sponsorship from the FreeBSD Foundation.
41 * Redistribution and use in source and binary forms, with or without
42 * modification, are permitted provided that the following conditions
44 * 1. Redistributions of source code must retain the above copyright
45 * notice, this list of conditions and the following disclaimer.
46 * 2. Redistributions in binary form must reproduce the above copyright
47 * notice, this list of conditions and the following disclaimer in the
48 * documentation and/or other materials provided with the distribution.
50 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
66 #include <sys/types.h>
67 #include <sys/module.h>
68 #include <sys/systm.h>
69 #include <sys/errno.h>
70 #include <sys/param.h>
71 #include <sys/kernel.h>
74 #include <sys/malloc.h>
75 #include <sys/queue.h>
78 #include <sys/mutex.h>
80 #include <sys/mount.h>
83 #include <sys/fcntl.h>
84 #include <sys/sysctl.h>
86 #include <sys/selinfo.h>
89 #include "fuse_internal.h"
92 #include <compat/linux/linux_errno.h>
93 #include <compat/linux/linux_errno.inc>
95 SDT_PROVIDER_DECLARE(fusefs);
98 * arg0: verbosity. Higher numbers give more verbose messages
99 * arg1: Textual message
101 SDT_PROBE_DEFINE2(fusefs, , device, trace, "int", "char*");
103 static struct cdev *fuse_dev;
105 static d_kqfilter_t fuse_device_filter;
106 static d_open_t fuse_device_open;
107 static d_poll_t fuse_device_poll;
108 static d_read_t fuse_device_read;
109 static d_write_t fuse_device_write;
111 static struct cdevsw fuse_device_cdevsw = {
112 .d_kqfilter = fuse_device_filter,
113 .d_open = fuse_device_open,
115 .d_poll = fuse_device_poll,
116 .d_read = fuse_device_read,
117 .d_write = fuse_device_write,
118 .d_version = D_VERSION,
121 static int fuse_device_filt_read(struct knote *kn, long hint);
122 static void fuse_device_filt_detach(struct knote *kn);
124 struct filterops fuse_device_rfiltops = {
126 .f_detach = fuse_device_filt_detach,
127 .f_event = fuse_device_filt_read,
130 /****************************
132 * >>> Fuse device op defs
134 ****************************/
137 fdata_dtor(void *arg)
139 struct fuse_data *fdata;
140 struct fuse_ticket *tick;
146 fdata_set_dead(fdata);
149 fuse_lck_mtx_lock(fdata->aw_mtx);
150 /* wakup poll()ers */
151 selwakeuppri(&fdata->ks_rsel, PZERO + 1);
152 /* Don't let syscall handlers wait in vain */
153 while ((tick = fuse_aw_pop(fdata))) {
154 fuse_lck_mtx_lock(tick->tk_aw_mtx);
155 fticket_set_answered(tick);
156 tick->tk_aw_errno = ENOTCONN;
158 fuse_lck_mtx_unlock(tick->tk_aw_mtx);
159 FUSE_ASSERT_AW_DONE(tick);
160 fuse_ticket_drop(tick);
162 fuse_lck_mtx_unlock(fdata->aw_mtx);
164 /* Cleanup unsent operations */
165 fuse_lck_mtx_lock(fdata->ms_mtx);
166 while ((tick = fuse_ms_pop(fdata))) {
167 fuse_ticket_drop(tick);
169 fuse_lck_mtx_unlock(fdata->ms_mtx);
172 fdata_trydestroy(fdata);
176 fuse_device_filter(struct cdev *dev, struct knote *kn)
178 struct fuse_data *data;
181 error = devfs_get_cdevpriv((void **)&data);
183 /* EVFILT_WRITE is not supported; the device is always ready to write */
184 if (error == 0 && kn->kn_filter == EVFILT_READ) {
185 kn->kn_fop = &fuse_device_rfiltops;
187 knlist_add(&data->ks_rsel.si_note, kn, 0);
189 } else if (error == 0) {
198 fuse_device_filt_detach(struct knote *kn)
200 struct fuse_data *data;
202 data = (struct fuse_data*)kn->kn_hook;
204 knlist_remove(&data->ks_rsel.si_note, kn, 0);
209 fuse_device_filt_read(struct knote *kn, long hint)
211 struct fuse_data *data;
214 data = (struct fuse_data*)kn->kn_hook;
217 mtx_assert(&data->ms_mtx, MA_OWNED);
218 if (fdata_get_dead(data)) {
219 kn->kn_flags |= EV_EOF;
220 kn->kn_fflags = ENODEV;
223 } else if (STAILQ_FIRST(&data->ms_head)) {
224 MPASS(data->ms_count >= 1);
225 kn->kn_data = data->ms_count;
235 * Resources are set up on a per-open basis
238 fuse_device_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
240 struct fuse_data *fdata;
243 SDT_PROBE2(fusefs, , device, trace, 1, "device open");
245 fdata = fdata_alloc(dev, td->td_ucred);
246 error = devfs_set_cdevpriv(fdata, fdata_dtor);
248 fdata_trydestroy(fdata);
250 SDT_PROBE2(fusefs, , device, trace, 1, "device open success");
255 fuse_device_poll(struct cdev *dev, int events, struct thread *td)
257 struct fuse_data *data;
258 int error, revents = 0;
260 error = devfs_get_cdevpriv((void **)&data);
263 (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
265 if (events & (POLLIN | POLLRDNORM)) {
266 fuse_lck_mtx_lock(data->ms_mtx);
267 if (fdata_get_dead(data) || STAILQ_FIRST(&data->ms_head))
268 revents |= events & (POLLIN | POLLRDNORM);
270 selrecord(td, &data->ks_rsel);
271 fuse_lck_mtx_unlock(data->ms_mtx);
273 if (events & (POLLOUT | POLLWRNORM)) {
274 revents |= events & (POLLOUT | POLLWRNORM);
280 * fuse_device_read hangs on the queue of VFS messages.
281 * When it's notified that there is a new one, it picks that and
282 * passes up to the daemon
285 fuse_device_read(struct cdev *dev, struct uio *uio, int ioflag)
288 struct fuse_data *data;
289 struct fuse_ticket *tick;
290 void *buf[] = {NULL, NULL, NULL};
294 SDT_PROBE2(fusefs, , device, trace, 1, "fuse device read");
296 err = devfs_get_cdevpriv((void **)&data);
300 fuse_lck_mtx_lock(data->ms_mtx);
302 if (fdata_get_dead(data)) {
303 SDT_PROBE2(fusefs, , device, trace, 2,
304 "we know early on that reader should be kicked so we "
305 "don't wait for news");
306 fuse_lck_mtx_unlock(data->ms_mtx);
309 if (!(tick = fuse_ms_pop(data))) {
310 /* check if we may block */
311 if (ioflag & O_NONBLOCK) {
312 /* get outa here soon */
313 fuse_lck_mtx_unlock(data->ms_mtx);
316 err = msleep(data, &data->ms_mtx, PCATCH, "fu_msg", 0);
318 fuse_lck_mtx_unlock(data->ms_mtx);
319 return (fdata_get_dead(data) ? ENODEV : err);
321 tick = fuse_ms_pop(data);
326 * We can get here if fuse daemon suddenly terminates,
327 * eg, by being hit by a SIGKILL
328 * -- and some other cases, too, tho not totally clear, when
329 * (cv_signal/wakeup_one signals the whole process ?)
331 SDT_PROBE2(fusefs, , device, trace, 1, "no message on thread");
334 fuse_lck_mtx_unlock(data->ms_mtx);
336 if (fdata_get_dead(data)) {
338 * somebody somewhere -- eg., umount routine --
339 * wants this liaison finished off
341 SDT_PROBE2(fusefs, , device, trace, 2,
342 "reader is to be sacked");
344 SDT_PROBE2(fusefs, , device, trace, 2, "weird -- "
345 "\"kick\" is set tho there is message");
346 FUSE_ASSERT_MS_DONE(tick);
347 fuse_ticket_drop(tick);
349 return (ENODEV); /* This should make the daemon get off
352 SDT_PROBE2(fusefs, , device, trace, 1,
353 "fuse device read message successfully");
355 KASSERT(tick->tk_ms_bufdata || tick->tk_ms_bufsize == 0,
356 ("non-null buf pointer with positive size"));
358 switch (tick->tk_ms_type) {
360 buf[0] = tick->tk_ms_fiov.base;
361 buflen[0] = tick->tk_ms_fiov.len;
364 buf[0] = tick->tk_ms_fiov.base;
365 buflen[0] = tick->tk_ms_fiov.len;
366 buf[1] = tick->tk_ms_bufdata;
367 buflen[1] = tick->tk_ms_bufsize;
370 panic("unknown message type for fuse_ticket %p", tick);
373 for (i = 0; buf[i]; i++) {
375 * Why not ban mercilessly stupid daemons who can't keep up
376 * with us? (There is no much use of a partial read here...)
379 * XXX note that in such cases Linux FUSE throws EIO at the
380 * syscall invoker and stands back to the message queue. The
381 * rationale should be made clear (and possibly adopt that
382 * behaviour). Keeping the current scheme at least makes
383 * fallacy as loud as possible...
385 if (uio->uio_resid < buflen[i]) {
386 fdata_set_dead(data);
387 SDT_PROBE2(fusefs, , device, trace, 2,
388 "daemon is stupid, kick it off...");
392 err = uiomove(buf[i], buflen[i], uio);
397 FUSE_ASSERT_MS_DONE(tick);
398 fuse_ticket_drop(tick);
404 fuse_ohead_audit(struct fuse_out_header *ohead, struct uio *uio)
406 if (uio->uio_resid + sizeof(struct fuse_out_header) != ohead->len) {
407 SDT_PROBE2(fusefs, , device, trace, 1,
408 "Format error: body size "
409 "differs from size claimed by header");
412 if (uio->uio_resid && ohead->unique != 0 && ohead->error) {
413 SDT_PROBE2(fusefs, , device, trace, 1,
414 "Format error: non zero error but message had a body");
421 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_notify,
422 "struct fuse_out_header*");
423 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_missing_ticket,
425 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_found,
426 "struct fuse_ticket*");
428 * fuse_device_write first reads the header sent by the daemon.
429 * If that's OK, looks up ticket/callback node by the unique id seen in header.
430 * If the callback node contains a handler function, the uio is passed over
434 fuse_device_write(struct cdev *dev, struct uio *uio, int ioflag)
436 struct fuse_out_header ohead;
438 struct fuse_data *data;
440 struct fuse_ticket *tick, *itick, *x_tick;
443 err = devfs_get_cdevpriv((void **)&data);
448 if (uio->uio_resid < sizeof(struct fuse_out_header)) {
449 SDT_PROBE2(fusefs, , device, trace, 1,
450 "fuse_device_write got less than a header!");
451 fdata_set_dead(data);
454 if ((err = uiomove(&ohead, sizeof(struct fuse_out_header), uio)) != 0)
457 if (data->linux_errnos != 0 && ohead.error != 0) {
459 if (err < 0 || err >= nitems(linux_to_bsd_errtbl))
462 /* '-', because it will get flipped again below */
463 ohead.error = -linux_to_bsd_errtbl[err];
467 * We check header information (which is redundant) and compare it
468 * with what we see. If we see some inconsistency we discard the
469 * whole answer and proceed on as if it had never existed. In
470 * particular, no pretender will be woken up, regardless the
471 * "unique" value in the header.
473 if ((err = fuse_ohead_audit(&ohead, uio))) {
474 fdata_set_dead(data);
477 /* Pass stuff over to callback if there is one installed */
479 /* Looking for ticket with the unique id of header */
480 fuse_lck_mtx_lock(data->aw_mtx);
481 TAILQ_FOREACH_SAFE(tick, &data->aw_head, tk_aw_link,
483 if (tick->tk_unique == ohead.unique) {
484 SDT_PROBE1(fusefs, , device, fuse_device_write_found,
487 fuse_aw_remove(tick);
491 if (found && tick->irq_unique > 0) {
493 * Discard the FUSE_INTERRUPT ticket that tried to interrupt
496 TAILQ_FOREACH_SAFE(itick, &data->aw_head, tk_aw_link,
498 if (itick->tk_unique == tick->irq_unique) {
499 fuse_aw_remove(itick);
500 fuse_ticket_drop(itick);
504 tick->irq_unique = 0;
506 fuse_lck_mtx_unlock(data->aw_mtx);
509 if (tick->tk_aw_handler) {
511 * We found a callback with proper handler. In this
512 * case the out header will be 0wnd by the callback,
513 * so the fun of freeing that is left for her.
514 * (Then, by all chance, she'll just get that's done
515 * via ticket_drop(), so no manual mucking
518 SDT_PROBE2(fusefs, , device, trace, 1,
519 "pass ticket to a callback");
520 /* Sanitize the linuxism of negative errnos */
522 memcpy(&tick->tk_aw_ohead, &ohead, sizeof(ohead));
523 err = tick->tk_aw_handler(tick, uio);
525 /* pretender doesn't wanna do anything with answer */
526 SDT_PROBE2(fusefs, , device, trace, 1,
527 "stuff devalidated, so we drop it");
531 * As aw_mtx was not held during the callback execution the
532 * ticket may have been inserted again. However, this is safe
533 * because fuse_ticket_drop() will deal with refcount anyway.
535 fuse_ticket_drop(tick);
536 } else if (ohead.unique == 0){
537 /* unique == 0 means asynchronous notification */
538 SDT_PROBE1(fusefs, , device, fuse_device_write_notify, &ohead);
539 switch (ohead.error) {
540 case FUSE_NOTIFY_INVAL_ENTRY:
541 err = fuse_internal_invalidate_entry(mp, uio);
543 case FUSE_NOTIFY_INVAL_INODE:
544 err = fuse_internal_invalidate_inode(mp, uio);
546 case FUSE_NOTIFY_RETRIEVE:
547 case FUSE_NOTIFY_STORE:
549 * Unimplemented. I don't know of any file systems
550 * that use them, and the protocol isn't sound anyway,
551 * since the notification messages don't include the
552 * inode's generation number. Without that, it's
553 * possible to manipulate the cache of the wrong vnode.
554 * Finally, it's not defined what this message should
555 * do for a file with dirty cache.
557 case FUSE_NOTIFY_POLL:
558 /* Unimplemented. See comments in fuse_vnops */
560 /* Not implemented */
564 /* no callback at all! */
565 SDT_PROBE1(fusefs, , device, fuse_device_write_missing_ticket,
567 if (ohead.error == -EAGAIN) {
569 * This was probably a response to a FUSE_INTERRUPT
570 * operation whose original operation is already
571 * complete. We can't store FUSE_INTERRUPT tickets
572 * indefinitely because their responses are optional.
573 * So we delete them when the original operation
574 * completes. And sadly the fuse_header_out doesn't
575 * identify the opcode, so we have to guess.
587 fuse_device_init(void)
590 fuse_dev = make_dev(&fuse_device_cdevsw, 0, UID_ROOT, GID_OPERATOR,
591 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH, "fuse");
592 if (fuse_dev == NULL)
598 fuse_device_destroy(void)
601 MPASS(fuse_dev != NULL);
602 destroy_dev(fuse_dev);