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/param.h>
68 #include <sys/module.h>
69 #include <sys/systm.h>
70 #include <sys/errno.h>
71 #include <sys/param.h>
72 #include <sys/kernel.h>
75 #include <sys/malloc.h>
76 #include <sys/queue.h>
79 #include <sys/mutex.h>
81 #include <sys/mount.h>
84 #include <sys/fcntl.h>
85 #include <sys/sysctl.h>
87 #include <sys/selinfo.h>
90 #include "fuse_internal.h"
93 #include <compat/linux/linux_errno.h>
94 #include <compat/linux/linux_errno.inc>
96 SDT_PROVIDER_DECLARE(fusefs);
99 * arg0: verbosity. Higher numbers give more verbose messages
100 * arg1: Textual message
102 SDT_PROBE_DEFINE2(fusefs, , device, trace, "int", "char*");
104 static struct cdev *fuse_dev;
106 static d_kqfilter_t fuse_device_filter;
107 static d_open_t fuse_device_open;
108 static d_poll_t fuse_device_poll;
109 static d_read_t fuse_device_read;
110 static d_write_t fuse_device_write;
112 static struct cdevsw fuse_device_cdevsw = {
113 .d_kqfilter = fuse_device_filter,
114 .d_open = fuse_device_open,
116 .d_poll = fuse_device_poll,
117 .d_read = fuse_device_read,
118 .d_write = fuse_device_write,
119 .d_version = D_VERSION,
122 static int fuse_device_filt_read(struct knote *kn, long hint);
123 static int fuse_device_filt_write(struct knote *kn, long hint);
124 static void fuse_device_filt_detach(struct knote *kn);
126 struct filterops fuse_device_rfiltops = {
128 .f_detach = fuse_device_filt_detach,
129 .f_event = fuse_device_filt_read,
132 struct filterops fuse_device_wfiltops = {
134 .f_event = fuse_device_filt_write,
137 /****************************
139 * >>> Fuse device op defs
141 ****************************/
144 fdata_dtor(void *arg)
146 struct fuse_data *fdata;
147 struct fuse_ticket *tick;
153 fdata_set_dead(fdata);
156 fuse_lck_mtx_lock(fdata->aw_mtx);
157 /* wakup poll()ers */
158 selwakeuppri(&fdata->ks_rsel, PZERO + 1);
159 /* Don't let syscall handlers wait in vain */
160 while ((tick = fuse_aw_pop(fdata))) {
161 fuse_lck_mtx_lock(tick->tk_aw_mtx);
162 fticket_set_answered(tick);
163 tick->tk_aw_errno = ENOTCONN;
165 fuse_lck_mtx_unlock(tick->tk_aw_mtx);
166 FUSE_ASSERT_AW_DONE(tick);
167 fuse_ticket_drop(tick);
169 fuse_lck_mtx_unlock(fdata->aw_mtx);
171 /* Cleanup unsent operations */
172 fuse_lck_mtx_lock(fdata->ms_mtx);
173 while ((tick = fuse_ms_pop(fdata))) {
174 fuse_ticket_drop(tick);
176 fuse_lck_mtx_unlock(fdata->ms_mtx);
179 fdata_trydestroy(fdata);
183 fuse_device_filter(struct cdev *dev, struct knote *kn)
185 struct fuse_data *data;
188 error = devfs_get_cdevpriv((void **)&data);
190 if (error == 0 && kn->kn_filter == EVFILT_READ) {
191 kn->kn_fop = &fuse_device_rfiltops;
193 knlist_add(&data->ks_rsel.si_note, kn, 0);
195 } else if (error == 0 && kn->kn_filter == EVFILT_WRITE) {
196 kn->kn_fop = &fuse_device_wfiltops;
198 } else if (error == 0) {
207 fuse_device_filt_detach(struct knote *kn)
209 struct fuse_data *data;
211 data = (struct fuse_data*)kn->kn_hook;
213 knlist_remove(&data->ks_rsel.si_note, kn, 0);
218 fuse_device_filt_read(struct knote *kn, long hint)
220 struct fuse_data *data;
223 data = (struct fuse_data*)kn->kn_hook;
226 mtx_assert(&data->ms_mtx, MA_OWNED);
227 if (fdata_get_dead(data)) {
228 kn->kn_flags |= EV_EOF;
229 kn->kn_fflags = ENODEV;
232 } else if (STAILQ_FIRST(&data->ms_head)) {
233 MPASS(data->ms_count >= 1);
234 kn->kn_data = data->ms_count;
244 fuse_device_filt_write(struct knote *kn, long hint)
249 /* The device is always ready to write, so we return 1*/
254 * Resources are set up on a per-open basis
257 fuse_device_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
259 struct fuse_data *fdata;
262 SDT_PROBE2(fusefs, , device, trace, 1, "device open");
264 fdata = fdata_alloc(dev, td->td_ucred);
265 error = devfs_set_cdevpriv(fdata, fdata_dtor);
267 fdata_trydestroy(fdata);
269 SDT_PROBE2(fusefs, , device, trace, 1, "device open success");
274 fuse_device_poll(struct cdev *dev, int events, struct thread *td)
276 struct fuse_data *data;
277 int error, revents = 0;
279 error = devfs_get_cdevpriv((void **)&data);
282 (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
284 if (events & (POLLIN | POLLRDNORM)) {
285 fuse_lck_mtx_lock(data->ms_mtx);
286 if (fdata_get_dead(data) || STAILQ_FIRST(&data->ms_head))
287 revents |= events & (POLLIN | POLLRDNORM);
289 selrecord(td, &data->ks_rsel);
290 fuse_lck_mtx_unlock(data->ms_mtx);
292 if (events & (POLLOUT | POLLWRNORM)) {
293 revents |= events & (POLLOUT | POLLWRNORM);
299 * fuse_device_read hangs on the queue of VFS messages.
300 * When it's notified that there is a new one, it picks that and
301 * passes up to the daemon
304 fuse_device_read(struct cdev *dev, struct uio *uio, int ioflag)
307 struct fuse_data *data;
308 struct fuse_ticket *tick;
312 SDT_PROBE2(fusefs, , device, trace, 1, "fuse device read");
314 err = devfs_get_cdevpriv((void **)&data);
318 fuse_lck_mtx_lock(data->ms_mtx);
320 if (fdata_get_dead(data)) {
321 SDT_PROBE2(fusefs, , device, trace, 2,
322 "we know early on that reader should be kicked so we "
323 "don't wait for news");
324 fuse_lck_mtx_unlock(data->ms_mtx);
327 if (!(tick = fuse_ms_pop(data))) {
328 /* check if we may block */
329 if (ioflag & O_NONBLOCK) {
330 /* get outa here soon */
331 fuse_lck_mtx_unlock(data->ms_mtx);
334 err = msleep(data, &data->ms_mtx, PCATCH, "fu_msg", 0);
336 fuse_lck_mtx_unlock(data->ms_mtx);
337 return (fdata_get_dead(data) ? ENODEV : err);
339 tick = fuse_ms_pop(data);
344 * We can get here if fuse daemon suddenly terminates,
345 * eg, by being hit by a SIGKILL
346 * -- and some other cases, too, tho not totally clear, when
347 * (cv_signal/wakeup_one signals the whole process ?)
349 SDT_PROBE2(fusefs, , device, trace, 1, "no message on thread");
352 fuse_lck_mtx_unlock(data->ms_mtx);
354 if (fdata_get_dead(data)) {
356 * somebody somewhere -- eg., umount routine --
357 * wants this liaison finished off
359 SDT_PROBE2(fusefs, , device, trace, 2,
360 "reader is to be sacked");
362 SDT_PROBE2(fusefs, , device, trace, 2, "weird -- "
363 "\"kick\" is set tho there is message");
364 FUSE_ASSERT_MS_DONE(tick);
365 fuse_ticket_drop(tick);
367 return (ENODEV); /* This should make the daemon get off
370 SDT_PROBE2(fusefs, , device, trace, 1,
371 "fuse device read message successfully");
373 buf = tick->tk_ms_fiov.base;
374 buflen = tick->tk_ms_fiov.len;
377 * Why not ban mercilessly stupid daemons who can't keep up
378 * with us? (There is no much use of a partial read here...)
381 * XXX note that in such cases Linux FUSE throws EIO at the
382 * syscall invoker and stands back to the message queue. The
383 * rationale should be made clear (and possibly adopt that
384 * behaviour). Keeping the current scheme at least makes
385 * fallacy as loud as possible...
387 if (uio->uio_resid < buflen) {
388 fdata_set_dead(data);
389 SDT_PROBE2(fusefs, , device, trace, 2,
390 "daemon is stupid, kick it off...");
393 err = uiomove(buf, buflen, uio);
396 FUSE_ASSERT_MS_DONE(tick);
397 fuse_ticket_drop(tick);
403 fuse_ohead_audit(struct fuse_out_header *ohead, struct uio *uio)
405 if (uio->uio_resid + sizeof(struct fuse_out_header) != ohead->len) {
406 SDT_PROBE2(fusefs, , device, trace, 1,
407 "Format error: body size "
408 "differs from size claimed by header");
411 if (uio->uio_resid && ohead->unique != 0 && ohead->error) {
412 SDT_PROBE2(fusefs, , device, trace, 1,
413 "Format error: non zero error but message had a body");
420 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_notify,
421 "struct fuse_out_header*");
422 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_missing_ticket,
424 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_found,
425 "struct fuse_ticket*");
427 * fuse_device_write first reads the header sent by the daemon.
428 * If that's OK, looks up ticket/callback node by the unique id seen in header.
429 * If the callback node contains a handler function, the uio is passed over
433 fuse_device_write(struct cdev *dev, struct uio *uio, int ioflag)
435 struct fuse_out_header ohead;
437 struct fuse_data *data;
439 struct fuse_ticket *tick, *itick, *x_tick;
442 err = devfs_get_cdevpriv((void **)&data);
447 if (uio->uio_resid < sizeof(struct fuse_out_header)) {
448 SDT_PROBE2(fusefs, , device, trace, 1,
449 "fuse_device_write got less than a header!");
450 fdata_set_dead(data);
453 if ((err = uiomove(&ohead, sizeof(struct fuse_out_header), uio)) != 0)
456 if (data->linux_errnos != 0 && ohead.error != 0) {
458 if (err < 0 || err >= nitems(linux_to_bsd_errtbl))
461 /* '-', because it will get flipped again below */
462 ohead.error = -linux_to_bsd_errtbl[err];
466 * We check header information (which is redundant) and compare it
467 * with what we see. If we see some inconsistency we discard the
468 * whole answer and proceed on as if it had never existed. In
469 * particular, no pretender will be woken up, regardless the
470 * "unique" value in the header.
472 if ((err = fuse_ohead_audit(&ohead, uio))) {
473 fdata_set_dead(data);
476 /* Pass stuff over to callback if there is one installed */
478 /* Looking for ticket with the unique id of header */
479 fuse_lck_mtx_lock(data->aw_mtx);
480 TAILQ_FOREACH_SAFE(tick, &data->aw_head, tk_aw_link,
482 if (tick->tk_unique == ohead.unique) {
483 SDT_PROBE1(fusefs, , device, fuse_device_write_found,
486 fuse_aw_remove(tick);
490 if (found && tick->irq_unique > 0) {
492 * Discard the FUSE_INTERRUPT ticket that tried to interrupt
495 TAILQ_FOREACH_SAFE(itick, &data->aw_head, tk_aw_link,
497 if (itick->tk_unique == tick->irq_unique) {
498 fuse_aw_remove(itick);
499 fuse_ticket_drop(itick);
503 tick->irq_unique = 0;
505 fuse_lck_mtx_unlock(data->aw_mtx);
508 if (tick->tk_aw_handler) {
510 * We found a callback with proper handler. In this
511 * case the out header will be 0wnd by the callback,
512 * so the fun of freeing that is left for her.
513 * (Then, by all chance, she'll just get that's done
514 * via ticket_drop(), so no manual mucking
517 SDT_PROBE2(fusefs, , device, trace, 1,
518 "pass ticket to a callback");
519 /* Sanitize the linuxism of negative errnos */
521 memcpy(&tick->tk_aw_ohead, &ohead, sizeof(ohead));
522 err = tick->tk_aw_handler(tick, uio);
524 /* pretender doesn't wanna do anything with answer */
525 SDT_PROBE2(fusefs, , device, trace, 1,
526 "stuff devalidated, so we drop it");
530 * As aw_mtx was not held during the callback execution the
531 * ticket may have been inserted again. However, this is safe
532 * because fuse_ticket_drop() will deal with refcount anyway.
534 fuse_ticket_drop(tick);
535 } else if (ohead.unique == 0){
536 /* unique == 0 means asynchronous notification */
537 SDT_PROBE1(fusefs, , device, fuse_device_write_notify, &ohead);
538 switch (ohead.error) {
539 case FUSE_NOTIFY_INVAL_ENTRY:
540 err = fuse_internal_invalidate_entry(mp, uio);
542 case FUSE_NOTIFY_INVAL_INODE:
543 err = fuse_internal_invalidate_inode(mp, uio);
545 case FUSE_NOTIFY_RETRIEVE:
546 case FUSE_NOTIFY_STORE:
548 * Unimplemented. I don't know of any file systems
549 * that use them, and the protocol isn't sound anyway,
550 * since the notification messages don't include the
551 * inode's generation number. Without that, it's
552 * possible to manipulate the cache of the wrong vnode.
553 * Finally, it's not defined what this message should
554 * do for a file with dirty cache.
556 case FUSE_NOTIFY_POLL:
557 /* Unimplemented. See comments in fuse_vnops */
559 /* Not implemented */
563 /* no callback at all! */
564 SDT_PROBE1(fusefs, , device, fuse_device_write_missing_ticket,
566 if (ohead.error == -EAGAIN) {
568 * This was probably a response to a FUSE_INTERRUPT
569 * operation whose original operation is already
570 * complete. We can't store FUSE_INTERRUPT tickets
571 * indefinitely because their responses are optional.
572 * So we delete them when the original operation
573 * completes. And sadly the fuse_header_out doesn't
574 * identify the opcode, so we have to guess.
586 fuse_device_init(void)
589 fuse_dev = make_dev(&fuse_device_cdevsw, 0, UID_ROOT, GID_OPERATOR,
590 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH, "fuse");
591 if (fuse_dev == NULL)
597 fuse_device_destroy(void)
600 MPASS(fuse_dev != NULL);
601 destroy_dev(fuse_dev);