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
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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,
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29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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31 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 * Copyright (C) 2005 Csaba Henk.
34 * All rights reserved.
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
39 * 1. Redistributions of source code must retain the above copyright
40 * notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 * notice, this list of conditions and the following disclaimer in the
43 * documentation and/or other materials provided with the distribution.
45 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
48 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
49 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
50 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
51 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
52 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
53 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
54 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 #include <sys/cdefs.h>
59 __FBSDID("$FreeBSD$");
61 #include <sys/types.h>
62 #include <sys/module.h>
63 #include <sys/systm.h>
64 #include <sys/errno.h>
65 #include <sys/param.h>
66 #include <sys/kernel.h>
69 #include <sys/malloc.h>
70 #include <sys/queue.h>
73 #include <sys/mutex.h>
75 #include <sys/mount.h>
78 #include <sys/fcntl.h>
79 #include <sys/sysctl.h>
81 #include <sys/selinfo.h>
86 SDT_PROVIDER_DECLARE(fuse);
89 * arg0: verbosity. Higher numbers give more verbose messages
90 * arg1: Textual message
92 SDT_PROBE_DEFINE2(fuse, , device, trace, "int", "char*");
94 static struct cdev *fuse_dev;
96 static d_open_t fuse_device_open;
97 static d_close_t fuse_device_close;
98 static d_poll_t fuse_device_poll;
99 static d_read_t fuse_device_read;
100 static d_write_t fuse_device_write;
102 static struct cdevsw fuse_device_cdevsw = {
103 .d_open = fuse_device_open,
104 .d_close = fuse_device_close,
106 .d_poll = fuse_device_poll,
107 .d_read = fuse_device_read,
108 .d_write = fuse_device_write,
109 .d_version = D_VERSION,
112 /****************************
114 * >>> Fuse device op defs
116 ****************************/
119 fdata_dtor(void *arg)
121 struct fuse_data *fdata;
124 fdata_trydestroy(fdata);
128 * Resources are set up on a per-open basis
131 fuse_device_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
133 struct fuse_data *fdata;
136 SDT_PROBE2(fuse, , device, trace, 1, "device open");
138 fdata = fdata_alloc(dev, td->td_ucred);
139 error = devfs_set_cdevpriv(fdata, fdata_dtor);
141 fdata_trydestroy(fdata);
143 SDT_PROBE2(fuse, , device, trace, 1, "device open success");
148 fuse_device_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
150 struct fuse_data *data;
151 struct fuse_ticket *tick;
154 error = devfs_get_cdevpriv((void **)&data);
158 panic("no fuse data upon fuse device close");
159 fdata_set_dead(data);
162 fuse_lck_mtx_lock(data->aw_mtx);
163 /* wakup poll()ers */
164 selwakeuppri(&data->ks_rsel, PZERO + 1);
165 /* Don't let syscall handlers wait in vain */
166 while ((tick = fuse_aw_pop(data))) {
167 fuse_lck_mtx_lock(tick->tk_aw_mtx);
168 fticket_set_answered(tick);
169 tick->tk_aw_errno = ENOTCONN;
171 fuse_lck_mtx_unlock(tick->tk_aw_mtx);
172 FUSE_ASSERT_AW_DONE(tick);
173 fuse_ticket_drop(tick);
175 fuse_lck_mtx_unlock(data->aw_mtx);
178 SDT_PROBE2(fuse, , device, trace, 1, "device close");
183 fuse_device_poll(struct cdev *dev, int events, struct thread *td)
185 struct fuse_data *data;
186 int error, revents = 0;
188 error = devfs_get_cdevpriv((void **)&data);
191 (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM));
193 if (events & (POLLIN | POLLRDNORM)) {
194 fuse_lck_mtx_lock(data->ms_mtx);
195 if (fdata_get_dead(data) || STAILQ_FIRST(&data->ms_head))
196 revents |= events & (POLLIN | POLLRDNORM);
198 selrecord(td, &data->ks_rsel);
199 fuse_lck_mtx_unlock(data->ms_mtx);
201 if (events & (POLLOUT | POLLWRNORM)) {
202 revents |= events & (POLLOUT | POLLWRNORM);
208 * fuse_device_read hangs on the queue of VFS messages.
209 * When it's notified that there is a new one, it picks that and
210 * passes up to the daemon
213 fuse_device_read(struct cdev *dev, struct uio *uio, int ioflag)
216 struct fuse_data *data;
217 struct fuse_ticket *tick;
218 void *buf[] = {NULL, NULL, NULL};
222 SDT_PROBE2(fuse, , device, trace, 1, "fuse device read");
224 err = devfs_get_cdevpriv((void **)&data);
228 fuse_lck_mtx_lock(data->ms_mtx);
230 if (fdata_get_dead(data)) {
231 SDT_PROBE2(fuse, , device, trace, 2,
232 "we know early on that reader should be kicked so we "
233 "don't wait for news");
234 fuse_lck_mtx_unlock(data->ms_mtx);
237 if (!(tick = fuse_ms_pop(data))) {
238 /* check if we may block */
239 if (ioflag & O_NONBLOCK) {
240 /* get outa here soon */
241 fuse_lck_mtx_unlock(data->ms_mtx);
244 err = msleep(data, &data->ms_mtx, PCATCH, "fu_msg", 0);
246 fuse_lck_mtx_unlock(data->ms_mtx);
247 return (fdata_get_dead(data) ? ENODEV : err);
249 tick = fuse_ms_pop(data);
254 * We can get here if fuse daemon suddenly terminates,
255 * eg, by being hit by a SIGKILL
256 * -- and some other cases, too, tho not totally clear, when
257 * (cv_signal/wakeup_one signals the whole process ?)
259 SDT_PROBE2(fuse, , device, trace, 1, "no message on thread");
262 fuse_lck_mtx_unlock(data->ms_mtx);
264 if (fdata_get_dead(data)) {
266 * somebody somewhere -- eg., umount routine --
267 * wants this liaison finished off
269 SDT_PROBE2(fuse, , device, trace, 2, "reader is to be sacked");
271 SDT_PROBE2(fuse, , device, trace, 2, "weird -- "
272 "\"kick\" is set tho there is message");
273 FUSE_ASSERT_MS_DONE(tick);
274 fuse_ticket_drop(tick);
276 return (ENODEV); /* This should make the daemon get off
279 SDT_PROBE2(fuse, , device, trace, 1,
280 "fuse device read message successfully");
282 KASSERT(tick->tk_ms_bufdata || tick->tk_ms_bufsize == 0,
283 ("non-null buf pointer with positive size"));
285 switch (tick->tk_ms_type) {
287 buf[0] = tick->tk_ms_fiov.base;
288 buflen[0] = tick->tk_ms_fiov.len;
291 buf[0] = tick->tk_ms_fiov.base;
292 buflen[0] = tick->tk_ms_fiov.len;
293 buf[1] = tick->tk_ms_bufdata;
294 buflen[1] = tick->tk_ms_bufsize;
297 panic("unknown message type for fuse_ticket %p", tick);
300 for (i = 0; buf[i]; i++) {
302 * Why not ban mercilessly stupid daemons who can't keep up
303 * with us? (There is no much use of a partial read here...)
306 * XXX note that in such cases Linux FUSE throws EIO at the
307 * syscall invoker and stands back to the message queue. The
308 * rationale should be made clear (and possibly adopt that
309 * behaviour). Keeping the current scheme at least makes
310 * fallacy as loud as possible...
312 if (uio->uio_resid < buflen[i]) {
313 fdata_set_dead(data);
314 SDT_PROBE2(fuse, , device, trace, 2,
315 "daemon is stupid, kick it off...");
319 err = uiomove(buf[i], buflen[i], uio);
324 FUSE_ASSERT_MS_DONE(tick);
325 fuse_ticket_drop(tick);
331 fuse_ohead_audit(struct fuse_out_header *ohead, struct uio *uio)
333 if (uio->uio_resid + sizeof(struct fuse_out_header) != ohead->len) {
334 SDT_PROBE2(fuse, , device, trace, 1, "Format error: body size "
335 "differs from size claimed by header");
338 if (uio->uio_resid && ohead->error) {
339 SDT_PROBE2(fuse, , device, trace, 1,
340 "Format error: non zero error but message had a body");
343 /* Sanitize the linuxism of negative errnos */
344 ohead->error = -(ohead->error);
349 SDT_PROBE_DEFINE1(fuse, , device, fuse_device_write_bumped_into_callback,
352 * fuse_device_write first reads the header sent by the daemon.
353 * If that's OK, looks up ticket/callback node by the unique id seen in header.
354 * If the callback node contains a handler function, the uio is passed over
358 fuse_device_write(struct cdev *dev, struct uio *uio, int ioflag)
360 struct fuse_out_header ohead;
362 struct fuse_data *data;
363 struct fuse_ticket *tick, *x_tick;
366 err = devfs_get_cdevpriv((void **)&data);
370 if (uio->uio_resid < sizeof(struct fuse_out_header)) {
371 SDT_PROBE2(fuse, , device, trace, 1,
372 "fuse_device_write got less than a header!");
373 fdata_set_dead(data);
376 if ((err = uiomove(&ohead, sizeof(struct fuse_out_header), uio)) != 0)
380 * We check header information (which is redundant) and compare it
381 * with what we see. If we see some inconsistency we discard the
382 * whole answer and proceed on as if it had never existed. In
383 * particular, no pretender will be woken up, regardless the
384 * "unique" value in the header.
386 if ((err = fuse_ohead_audit(&ohead, uio))) {
387 fdata_set_dead(data);
390 /* Pass stuff over to callback if there is one installed */
392 /* Looking for ticket with the unique id of header */
393 fuse_lck_mtx_lock(data->aw_mtx);
394 TAILQ_FOREACH_SAFE(tick, &data->aw_head, tk_aw_link,
396 SDT_PROBE1(fuse, , device,
397 fuse_device_write_bumped_into_callback,
399 if (tick->tk_unique == ohead.unique) {
401 fuse_aw_remove(tick);
405 fuse_lck_mtx_unlock(data->aw_mtx);
408 if (tick->tk_aw_handler) {
410 * We found a callback with proper handler. In this
411 * case the out header will be 0wnd by the callback,
412 * so the fun of freeing that is left for her.
413 * (Then, by all chance, she'll just get that's done
414 * via ticket_drop(), so no manual mucking
417 SDT_PROBE2(fuse, , device, trace, 1,
418 "pass ticket to a callback");
419 memcpy(&tick->tk_aw_ohead, &ohead, sizeof(ohead));
420 err = tick->tk_aw_handler(tick, uio);
422 /* pretender doesn't wanna do anything with answer */
423 SDT_PROBE2(fuse, , device, trace, 1,
424 "stuff devalidated, so we drop it");
428 * As aw_mtx was not held during the callback execution the
429 * ticket may have been inserted again. However, this is safe
430 * because fuse_ticket_drop() will deal with refcount anyway.
432 fuse_ticket_drop(tick);
434 /* no callback at all! */
435 SDT_PROBE2(fuse, , device, trace, 1,
436 "erhm, no handler for this response");
444 fuse_device_init(void)
447 fuse_dev = make_dev(&fuse_device_cdevsw, 0, UID_ROOT, GID_OPERATOR,
448 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP, "fuse");
449 if (fuse_dev == NULL)
455 fuse_device_destroy(void)
458 MPASS(fuse_dev != NULL);
459 destroy_dev(fuse_dev);