1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 2007-2009 Google Inc. 5 * 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 are 9 * met: 10 * 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 16 * distribution. 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. 20 * 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. 32 * 33 * Copyright (C) 2005 Csaba Henk. 34 * All rights reserved. 35 * 36 * Copyright (c) 2019 The FreeBSD Foundation 37 * 38 * Portions of this software were developed by BFF Storage Systems, LLC under 39 * sponsorship from the FreeBSD Foundation. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 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. 49 * 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 60 * SUCH DAMAGE. 61 */ 62 63 #include <sys/cdefs.h> 64 __FBSDID("$FreeBSD$"); 65 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> 72 #include <sys/conf.h> 73 #include <sys/uio.h> 74 #include <sys/malloc.h> 75 #include <sys/queue.h> 76 #include <sys/lock.h> 77 #include <sys/sx.h> 78 #include <sys/mutex.h> 79 #include <sys/proc.h> 80 #include <sys/mount.h> 81 #include <sys/sdt.h> 82 #include <sys/stat.h> 83 #include <sys/fcntl.h> 84 #include <sys/sysctl.h> 85 #include <sys/poll.h> 86 #include <sys/selinfo.h> 87 88 #include "fuse.h" 89 #include "fuse_internal.h" 90 #include "fuse_ipc.h" 91 92 #include <compat/linux/linux_errno.h> 93 #include <compat/linux/linux_errno.inc> 94 95 SDT_PROVIDER_DECLARE(fusefs); 96 /* 97 * Fuse trace probe: 98 * arg0: verbosity. Higher numbers give more verbose messages 99 * arg1: Textual message 100 */ 101 SDT_PROBE_DEFINE2(fusefs, , device, trace, "int", "char*"); 102 103 static struct cdev *fuse_dev; 104 105 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; 110 111 static struct cdevsw fuse_device_cdevsw = { 112 .d_kqfilter = fuse_device_filter, 113 .d_open = fuse_device_open, 114 .d_name = "fuse", 115 .d_poll = fuse_device_poll, 116 .d_read = fuse_device_read, 117 .d_write = fuse_device_write, 118 .d_version = D_VERSION, 119 }; 120 121 static int fuse_device_filt_read(struct knote *kn, long hint); 122 static int fuse_device_filt_write(struct knote *kn, long hint); 123 static void fuse_device_filt_detach(struct knote *kn); 124 125 struct filterops fuse_device_rfiltops = { 126 .f_isfd = 1, 127 .f_detach = fuse_device_filt_detach, 128 .f_event = fuse_device_filt_read, 129 }; 130 131 struct filterops fuse_device_wfiltops = { 132 .f_isfd = 1, 133 .f_event = fuse_device_filt_write, 134 }; 135 136 /**************************** 137 * 138 * >>> Fuse device op defs 139 * 140 ****************************/ 141 142 static void 143 fdata_dtor(void *arg) 144 { 145 struct fuse_data *fdata; 146 struct fuse_ticket *tick; 147 148 fdata = arg; 149 if (fdata == NULL) 150 return; 151 152 fdata_set_dead(fdata); 153 154 FUSE_LOCK(); 155 fuse_lck_mtx_lock(fdata->aw_mtx); 156 /* wakup poll()ers */ 157 selwakeuppri(&fdata->ks_rsel, PZERO + 1); 158 /* Don't let syscall handlers wait in vain */ 159 while ((tick = fuse_aw_pop(fdata))) { 160 fuse_lck_mtx_lock(tick->tk_aw_mtx); 161 fticket_set_answered(tick); 162 tick->tk_aw_errno = ENOTCONN; 163 wakeup(tick); 164 fuse_lck_mtx_unlock(tick->tk_aw_mtx); 165 FUSE_ASSERT_AW_DONE(tick); 166 fuse_ticket_drop(tick); 167 } 168 fuse_lck_mtx_unlock(fdata->aw_mtx); 169 170 /* Cleanup unsent operations */ 171 fuse_lck_mtx_lock(fdata->ms_mtx); 172 while ((tick = fuse_ms_pop(fdata))) { 173 fuse_ticket_drop(tick); 174 } 175 fuse_lck_mtx_unlock(fdata->ms_mtx); 176 FUSE_UNLOCK(); 177 178 fdata_trydestroy(fdata); 179 } 180 181 static int 182 fuse_device_filter(struct cdev *dev, struct knote *kn) 183 { 184 struct fuse_data *data; 185 int error; 186 187 error = devfs_get_cdevpriv((void **)&data); 188 189 if (error == 0 && kn->kn_filter == EVFILT_READ) { 190 kn->kn_fop = &fuse_device_rfiltops; 191 kn->kn_hook = data; 192 knlist_add(&data->ks_rsel.si_note, kn, 0); 193 error = 0; 194 } else if (error == 0 && kn->kn_filter == EVFILT_WRITE) { 195 kn->kn_fop = &fuse_device_wfiltops; 196 error = 0; 197 } else if (error == 0) { 198 error = EINVAL; 199 kn->kn_data = error; 200 } 201 202 return (error); 203 } 204 205 static void 206 fuse_device_filt_detach(struct knote *kn) 207 { 208 struct fuse_data *data; 209 210 data = (struct fuse_data*)kn->kn_hook; 211 MPASS(data != NULL); 212 knlist_remove(&data->ks_rsel.si_note, kn, 0); 213 kn->kn_hook = NULL; 214 } 215 216 static int 217 fuse_device_filt_read(struct knote *kn, long hint) 218 { 219 struct fuse_data *data; 220 int ready; 221 222 data = (struct fuse_data*)kn->kn_hook; 223 MPASS(data != NULL); 224 225 mtx_assert(&data->ms_mtx, MA_OWNED); 226 if (fdata_get_dead(data)) { 227 kn->kn_flags |= EV_EOF; 228 kn->kn_fflags = ENODEV; 229 kn->kn_data = 1; 230 ready = 1; 231 } else if (STAILQ_FIRST(&data->ms_head)) { 232 MPASS(data->ms_count >= 1); 233 kn->kn_data = data->ms_count; 234 ready = 1; 235 } else { 236 ready = 0; 237 } 238 239 return (ready); 240 } 241 242 static int 243 fuse_device_filt_write(struct knote *kn, long hint) 244 { 245 246 kn->kn_data = 0; 247 248 /* The device is always ready to write, so we return 1*/ 249 return (1); 250 } 251 252 /* 253 * Resources are set up on a per-open basis 254 */ 255 static int 256 fuse_device_open(struct cdev *dev, int oflags, int devtype, struct thread *td) 257 { 258 struct fuse_data *fdata; 259 int error; 260 261 SDT_PROBE2(fusefs, , device, trace, 1, "device open"); 262 263 fdata = fdata_alloc(dev, td->td_ucred); 264 error = devfs_set_cdevpriv(fdata, fdata_dtor); 265 if (error != 0) 266 fdata_trydestroy(fdata); 267 else 268 SDT_PROBE2(fusefs, , device, trace, 1, "device open success"); 269 return (error); 270 } 271 272 int 273 fuse_device_poll(struct cdev *dev, int events, struct thread *td) 274 { 275 struct fuse_data *data; 276 int error, revents = 0; 277 278 error = devfs_get_cdevpriv((void **)&data); 279 if (error != 0) 280 return (events & 281 (POLLHUP|POLLIN|POLLRDNORM|POLLOUT|POLLWRNORM)); 282 283 if (events & (POLLIN | POLLRDNORM)) { 284 fuse_lck_mtx_lock(data->ms_mtx); 285 if (fdata_get_dead(data) || STAILQ_FIRST(&data->ms_head)) 286 revents |= events & (POLLIN | POLLRDNORM); 287 else 288 selrecord(td, &data->ks_rsel); 289 fuse_lck_mtx_unlock(data->ms_mtx); 290 } 291 if (events & (POLLOUT | POLLWRNORM)) { 292 revents |= events & (POLLOUT | POLLWRNORM); 293 } 294 return (revents); 295 } 296 297 /* 298 * fuse_device_read hangs on the queue of VFS messages. 299 * When it's notified that there is a new one, it picks that and 300 * passes up to the daemon 301 */ 302 int 303 fuse_device_read(struct cdev *dev, struct uio *uio, int ioflag) 304 { 305 int err; 306 struct fuse_data *data; 307 struct fuse_ticket *tick; 308 void *buf; 309 int buflen; 310 311 SDT_PROBE2(fusefs, , device, trace, 1, "fuse device read"); 312 313 err = devfs_get_cdevpriv((void **)&data); 314 if (err != 0) 315 return (err); 316 317 fuse_lck_mtx_lock(data->ms_mtx); 318 again: 319 if (fdata_get_dead(data)) { 320 SDT_PROBE2(fusefs, , device, trace, 2, 321 "we know early on that reader should be kicked so we " 322 "don't wait for news"); 323 fuse_lck_mtx_unlock(data->ms_mtx); 324 return (ENODEV); 325 } 326 if (!(tick = fuse_ms_pop(data))) { 327 /* check if we may block */ 328 if (ioflag & O_NONBLOCK) { 329 /* get outa here soon */ 330 fuse_lck_mtx_unlock(data->ms_mtx); 331 return (EAGAIN); 332 } else { 333 err = msleep(data, &data->ms_mtx, PCATCH, "fu_msg", 0); 334 if (err != 0) { 335 fuse_lck_mtx_unlock(data->ms_mtx); 336 return (fdata_get_dead(data) ? ENODEV : err); 337 } 338 tick = fuse_ms_pop(data); 339 } 340 } 341 if (!tick) { 342 /* 343 * We can get here if fuse daemon suddenly terminates, 344 * eg, by being hit by a SIGKILL 345 * -- and some other cases, too, tho not totally clear, when 346 * (cv_signal/wakeup_one signals the whole process ?) 347 */ 348 SDT_PROBE2(fusefs, , device, trace, 1, "no message on thread"); 349 goto again; 350 } 351 fuse_lck_mtx_unlock(data->ms_mtx); 352 353 if (fdata_get_dead(data)) { 354 /* 355 * somebody somewhere -- eg., umount routine -- 356 * wants this liaison finished off 357 */ 358 SDT_PROBE2(fusefs, , device, trace, 2, 359 "reader is to be sacked"); 360 if (tick) { 361 SDT_PROBE2(fusefs, , device, trace, 2, "weird -- " 362 "\"kick\" is set tho there is message"); 363 FUSE_ASSERT_MS_DONE(tick); 364 fuse_ticket_drop(tick); 365 } 366 return (ENODEV); /* This should make the daemon get off 367 * of us */ 368 } 369 SDT_PROBE2(fusefs, , device, trace, 1, 370 "fuse device read message successfully"); 371 372 buf = tick->tk_ms_fiov.base; 373 buflen = tick->tk_ms_fiov.len; 374 375 /* 376 * Why not ban mercilessly stupid daemons who can't keep up 377 * with us? (There is no much use of a partial read here...) 378 */ 379 /* 380 * XXX note that in such cases Linux FUSE throws EIO at the 381 * syscall invoker and stands back to the message queue. The 382 * rationale should be made clear (and possibly adopt that 383 * behaviour). Keeping the current scheme at least makes 384 * fallacy as loud as possible... 385 */ 386 if (uio->uio_resid < buflen) { 387 fdata_set_dead(data); 388 SDT_PROBE2(fusefs, , device, trace, 2, 389 "daemon is stupid, kick it off..."); 390 err = ENODEV; 391 } else { 392 err = uiomove(buf, buflen, uio); 393 } 394 395 FUSE_ASSERT_MS_DONE(tick); 396 fuse_ticket_drop(tick); 397 398 return (err); 399 } 400 401 static inline int 402 fuse_ohead_audit(struct fuse_out_header *ohead, struct uio *uio) 403 { 404 if (uio->uio_resid + sizeof(struct fuse_out_header) != ohead->len) { 405 SDT_PROBE2(fusefs, , device, trace, 1, 406 "Format error: body size " 407 "differs from size claimed by header"); 408 return (EINVAL); 409 } 410 if (uio->uio_resid && ohead->unique != 0 && ohead->error) { 411 SDT_PROBE2(fusefs, , device, trace, 1, 412 "Format error: non zero error but message had a body"); 413 return (EINVAL); 414 } 415 416 return (0); 417 } 418 419 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_notify, 420 "struct fuse_out_header*"); 421 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_missing_ticket, 422 "uint64_t"); 423 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_found, 424 "struct fuse_ticket*"); 425 /* 426 * fuse_device_write first reads the header sent by the daemon. 427 * If that's OK, looks up ticket/callback node by the unique id seen in header. 428 * If the callback node contains a handler function, the uio is passed over 429 * that. 430 */ 431 static int 432 fuse_device_write(struct cdev *dev, struct uio *uio, int ioflag) 433 { 434 struct fuse_out_header ohead; 435 int err = 0; 436 struct fuse_data *data; 437 struct mount *mp; 438 struct fuse_ticket *tick, *itick, *x_tick; 439 int found = 0; 440 441 err = devfs_get_cdevpriv((void **)&data); 442 if (err != 0) 443 return (err); 444 mp = data->mp; 445 446 if (uio->uio_resid < sizeof(struct fuse_out_header)) { 447 SDT_PROBE2(fusefs, , device, trace, 1, 448 "fuse_device_write got less than a header!"); 449 fdata_set_dead(data); 450 return (EINVAL); 451 } 452 if ((err = uiomove(&ohead, sizeof(struct fuse_out_header), uio)) != 0) 453 return (err); 454 455 if (data->linux_errnos != 0 && ohead.error != 0) { 456 err = -ohead.error; 457 if (err < 0 || err >= nitems(linux_to_bsd_errtbl)) 458 return (EINVAL); 459 460 /* '-', because it will get flipped again below */ 461 ohead.error = -linux_to_bsd_errtbl[err]; 462 } 463 464 /* 465 * We check header information (which is redundant) and compare it 466 * with what we see. If we see some inconsistency we discard the 467 * whole answer and proceed on as if it had never existed. In 468 * particular, no pretender will be woken up, regardless the 469 * "unique" value in the header. 470 */ 471 if ((err = fuse_ohead_audit(&ohead, uio))) { 472 fdata_set_dead(data); 473 return (err); 474 } 475 /* Pass stuff over to callback if there is one installed */ 476 477 /* Looking for ticket with the unique id of header */ 478 fuse_lck_mtx_lock(data->aw_mtx); 479 TAILQ_FOREACH_SAFE(tick, &data->aw_head, tk_aw_link, 480 x_tick) { 481 if (tick->tk_unique == ohead.unique) { 482 SDT_PROBE1(fusefs, , device, fuse_device_write_found, 483 tick); 484 found = 1; 485 fuse_aw_remove(tick); 486 break; 487 } 488 } 489 if (found && tick->irq_unique > 0) { 490 /* 491 * Discard the FUSE_INTERRUPT ticket that tried to interrupt 492 * this operation 493 */ 494 TAILQ_FOREACH_SAFE(itick, &data->aw_head, tk_aw_link, 495 x_tick) { 496 if (itick->tk_unique == tick->irq_unique) { 497 fuse_aw_remove(itick); 498 fuse_ticket_drop(itick); 499 break; 500 } 501 } 502 tick->irq_unique = 0; 503 } 504 fuse_lck_mtx_unlock(data->aw_mtx); 505 506 if (found) { 507 if (tick->tk_aw_handler) { 508 /* 509 * We found a callback with proper handler. In this 510 * case the out header will be 0wnd by the callback, 511 * so the fun of freeing that is left for her. 512 * (Then, by all chance, she'll just get that's done 513 * via ticket_drop(), so no manual mucking 514 * around...) 515 */ 516 SDT_PROBE2(fusefs, , device, trace, 1, 517 "pass ticket to a callback"); 518 /* Sanitize the linuxism of negative errnos */ 519 ohead.error *= -1; 520 memcpy(&tick->tk_aw_ohead, &ohead, sizeof(ohead)); 521 err = tick->tk_aw_handler(tick, uio); 522 } else { 523 /* pretender doesn't wanna do anything with answer */ 524 SDT_PROBE2(fusefs, , device, trace, 1, 525 "stuff devalidated, so we drop it"); 526 } 527 528 /* 529 * As aw_mtx was not held during the callback execution the 530 * ticket may have been inserted again. However, this is safe 531 * because fuse_ticket_drop() will deal with refcount anyway. 532 */ 533 fuse_ticket_drop(tick); 534 } else if (ohead.unique == 0){ 535 /* unique == 0 means asynchronous notification */ 536 SDT_PROBE1(fusefs, , device, fuse_device_write_notify, &ohead); 537 switch (ohead.error) { 538 case FUSE_NOTIFY_INVAL_ENTRY: 539 err = fuse_internal_invalidate_entry(mp, uio); 540 break; 541 case FUSE_NOTIFY_INVAL_INODE: 542 err = fuse_internal_invalidate_inode(mp, uio); 543 break; 544 case FUSE_NOTIFY_RETRIEVE: 545 case FUSE_NOTIFY_STORE: 546 /* 547 * Unimplemented. I don't know of any file systems 548 * that use them, and the protocol isn't sound anyway, 549 * since the notification messages don't include the 550 * inode's generation number. Without that, it's 551 * possible to manipulate the cache of the wrong vnode. 552 * Finally, it's not defined what this message should 553 * do for a file with dirty cache. 554 */ 555 case FUSE_NOTIFY_POLL: 556 /* Unimplemented. See comments in fuse_vnops */ 557 default: 558 /* Not implemented */ 559 err = ENOSYS; 560 } 561 } else { 562 /* no callback at all! */ 563 SDT_PROBE1(fusefs, , device, fuse_device_write_missing_ticket, 564 ohead.unique); 565 if (ohead.error == -EAGAIN) { 566 /* 567 * This was probably a response to a FUSE_INTERRUPT 568 * operation whose original operation is already 569 * complete. We can't store FUSE_INTERRUPT tickets 570 * indefinitely because their responses are optional. 571 * So we delete them when the original operation 572 * completes. And sadly the fuse_header_out doesn't 573 * identify the opcode, so we have to guess. 574 */ 575 err = 0; 576 } else { 577 err = EINVAL; 578 } 579 } 580 581 return (err); 582 } 583 584 int 585 fuse_device_init(void) 586 { 587 588 fuse_dev = make_dev(&fuse_device_cdevsw, 0, UID_ROOT, GID_OPERATOR, 589 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH, "fuse"); 590 if (fuse_dev == NULL) 591 return (ENOMEM); 592 return (0); 593 } 594 595 void 596 fuse_device_destroy(void) 597 { 598 599 MPASS(fuse_dev != NULL); 600 destroy_dev(fuse_dev); 601 } 602