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/types.h> 64 #include <sys/param.h> 65 #include <sys/module.h> 66 #include <sys/systm.h> 67 #include <sys/errno.h> 68 #include <sys/param.h> 69 #include <sys/kernel.h> 70 #include <sys/conf.h> 71 #include <sys/uio.h> 72 #include <sys/malloc.h> 73 #include <sys/queue.h> 74 #include <sys/lock.h> 75 #include <sys/sx.h> 76 #include <sys/mutex.h> 77 #include <sys/proc.h> 78 #include <sys/mount.h> 79 #include <sys/sdt.h> 80 #include <sys/stat.h> 81 #include <sys/fcntl.h> 82 #include <sys/sysctl.h> 83 #include <sys/poll.h> 84 #include <sys/selinfo.h> 85 #define EXTERR_CATEGORY EXTERR_CAT_FUSE 86 #include <sys/exterrvar.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 static const 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 static const 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); 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 = EXTERROR(EINVAL, "Unsupported kevent filter"); 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 (EXTERROR(ENODEV, "This FUSE session is about to be closed")); 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 if (fdata_get_dead(data)) 337 err = EXTERROR(ENODEV, 338 "This FUSE session is about to be closed"); 339 return (err); 340 } 341 tick = fuse_ms_pop(data); 342 } 343 } 344 if (!tick) { 345 /* 346 * We can get here if fuse daemon suddenly terminates, 347 * eg, by being hit by a SIGKILL 348 * -- and some other cases, too, tho not totally clear, when 349 * (cv_signal/wakeup_one signals the whole process ?) 350 */ 351 SDT_PROBE2(fusefs, , device, trace, 1, "no message on thread"); 352 goto again; 353 } 354 fuse_lck_mtx_unlock(data->ms_mtx); 355 356 if (fdata_get_dead(data)) { 357 /* 358 * somebody somewhere -- eg., umount routine -- 359 * wants this liaison finished off 360 */ 361 SDT_PROBE2(fusefs, , device, trace, 2, 362 "reader is to be sacked"); 363 if (tick) { 364 SDT_PROBE2(fusefs, , device, trace, 2, "weird -- " 365 "\"kick\" is set tho there is message"); 366 FUSE_ASSERT_MS_DONE(tick); 367 fuse_ticket_drop(tick); 368 } 369 /* This should make the daemon get off of us */ 370 return (EXTERROR(ENODEV, "This FUSE session is about to be closed")); 371 } 372 SDT_PROBE2(fusefs, , device, trace, 1, 373 "fuse device read message successfully"); 374 375 buf = tick->tk_ms_fiov.base; 376 buflen = tick->tk_ms_fiov.len; 377 378 /* 379 * Why not ban mercilessly stupid daemons who can't keep up 380 * with us? (There is no much use of a partial read here...) 381 */ 382 /* 383 * XXX note that in such cases Linux FUSE throws EIO at the 384 * syscall invoker and stands back to the message queue. The 385 * rationale should be made clear (and possibly adopt that 386 * behaviour). Keeping the current scheme at least makes 387 * fallacy as loud as possible... 388 */ 389 if (uio->uio_resid < buflen) { 390 fdata_set_dead(data); 391 SDT_PROBE2(fusefs, , device, trace, 2, 392 "daemon is stupid, kick it off..."); 393 err = EXTERROR(ENODEV, "Partial read attempted"); 394 } else { 395 err = uiomove(buf, buflen, uio); 396 } 397 398 FUSE_ASSERT_MS_DONE(tick); 399 fuse_ticket_drop(tick); 400 401 return (err); 402 } 403 404 static inline int 405 fuse_ohead_audit(struct fuse_out_header *ohead, struct uio *uio) 406 { 407 if (uio->uio_resid + sizeof(struct fuse_out_header) != ohead->len) { 408 SDT_PROBE2(fusefs, , device, trace, 1, 409 "Format error: body size " 410 "differs from size claimed by header"); 411 return (EXTERROR(EINVAL, "Format error: body size " 412 "differs from size claimed by header")); 413 } 414 if (uio->uio_resid && ohead->unique != 0 && ohead->error) { 415 SDT_PROBE2(fusefs, , device, trace, 1, 416 "Format error: non zero error but message had a body"); 417 return (EXTERROR(EINVAL, "Format error: non zero error, " 418 "but message had a body")); 419 } 420 421 return (0); 422 } 423 424 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_notify, 425 "struct fuse_out_header*"); 426 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_missing_ticket, 427 "uint64_t"); 428 SDT_PROBE_DEFINE1(fusefs, , device, fuse_device_write_found, 429 "struct fuse_ticket*"); 430 /* 431 * fuse_device_write first reads the header sent by the daemon. 432 * If that's OK, looks up ticket/callback node by the unique id seen in header. 433 * If the callback node contains a handler function, the uio is passed over 434 * that. 435 */ 436 static int 437 fuse_device_write(struct cdev *dev, struct uio *uio, int ioflag) 438 { 439 struct fuse_out_header ohead; 440 int err = 0; 441 struct fuse_data *data; 442 struct mount *mp; 443 struct fuse_ticket *tick, *itick, *x_tick; 444 int found = 0; 445 446 err = devfs_get_cdevpriv((void **)&data); 447 if (err != 0) 448 return (err); 449 450 if (uio->uio_resid < sizeof(struct fuse_out_header)) { 451 SDT_PROBE2(fusefs, , device, trace, 1, 452 "fuse_device_write got less than a header!"); 453 fdata_set_dead(data); 454 return (EXTERROR(EINVAL, "fuse_device_write got less than a header!")); 455 } 456 if ((err = uiomove(&ohead, sizeof(struct fuse_out_header), uio)) != 0) 457 return (err); 458 459 if (data->linux_errnos != 0 && ohead.error != 0) { 460 err = -ohead.error; 461 if (err < 0 || err >= nitems(linux_to_bsd_errtbl)) 462 return (EXTERROR(EINVAL, "Unknown Linux errno", err)); 463 464 /* '-', because it will get flipped again below */ 465 ohead.error = -linux_to_bsd_errtbl[err]; 466 } 467 468 /* 469 * We check header information (which is redundant) and compare it 470 * with what we see. If we see some inconsistency we discard the 471 * whole answer and proceed on as if it had never existed. In 472 * particular, no pretender will be woken up, regardless the 473 * "unique" value in the header. 474 */ 475 if ((err = fuse_ohead_audit(&ohead, uio))) { 476 fdata_set_dead(data); 477 return (err); 478 } 479 /* Pass stuff over to callback if there is one installed */ 480 481 /* Looking for ticket with the unique id of header */ 482 fuse_lck_mtx_lock(data->aw_mtx); 483 TAILQ_FOREACH_SAFE(tick, &data->aw_head, tk_aw_link, 484 x_tick) { 485 if (tick->tk_unique == ohead.unique) { 486 SDT_PROBE1(fusefs, , device, fuse_device_write_found, 487 tick); 488 found = 1; 489 fuse_aw_remove(tick); 490 break; 491 } 492 } 493 if (found && tick->irq_unique > 0) { 494 /* 495 * Discard the FUSE_INTERRUPT ticket that tried to interrupt 496 * this operation 497 */ 498 TAILQ_FOREACH_SAFE(itick, &data->aw_head, tk_aw_link, 499 x_tick) { 500 if (itick->tk_unique == tick->irq_unique) { 501 fuse_aw_remove(itick); 502 fuse_ticket_drop(itick); 503 break; 504 } 505 } 506 tick->irq_unique = 0; 507 } 508 fuse_lck_mtx_unlock(data->aw_mtx); 509 510 if (found) { 511 if (tick->tk_aw_handler) { 512 /* 513 * We found a callback with proper handler. In this 514 * case the out header will be 0wnd by the callback, 515 * so the fun of freeing that is left for her. 516 * (Then, by all chance, she'll just get that's done 517 * via ticket_drop(), so no manual mucking 518 * around...) 519 */ 520 SDT_PROBE2(fusefs, , device, trace, 1, 521 "pass ticket to a callback"); 522 /* Sanitize the linuxism of negative errnos */ 523 ohead.error *= -1; 524 if (ohead.error < 0 || ohead.error > ELAST) { 525 /* Illegal error code */ 526 ohead.error = EIO; 527 memcpy(&tick->tk_aw_ohead, &ohead, 528 sizeof(ohead)); 529 tick->tk_aw_handler(tick, uio); 530 err = EXTERROR(EINVAL, "Unknown errno", ohead.error); 531 } else { 532 memcpy(&tick->tk_aw_ohead, &ohead, 533 sizeof(ohead)); 534 err = tick->tk_aw_handler(tick, uio); 535 } 536 } else { 537 /* pretender doesn't wanna do anything with answer */ 538 SDT_PROBE2(fusefs, , device, trace, 1, 539 "stuff devalidated, so we drop it"); 540 } 541 542 /* 543 * As aw_mtx was not held during the callback execution the 544 * ticket may have been inserted again. However, this is safe 545 * because fuse_ticket_drop() will deal with refcount anyway. 546 */ 547 fuse_ticket_drop(tick); 548 } else if (ohead.unique == 0){ 549 /* unique == 0 means asynchronous notification */ 550 SDT_PROBE1(fusefs, , device, fuse_device_write_notify, &ohead); 551 mp = data->mp; 552 vfs_ref(mp); 553 err = vfs_busy(mp, 0); 554 vfs_rel(mp); 555 if (err) 556 return (err); 557 558 switch (ohead.error) { 559 case FUSE_NOTIFY_INVAL_ENTRY: 560 err = fuse_internal_invalidate_entry(mp, uio); 561 break; 562 case FUSE_NOTIFY_INVAL_INODE: 563 err = fuse_internal_invalidate_inode(mp, uio); 564 break; 565 case FUSE_NOTIFY_RETRIEVE: 566 case FUSE_NOTIFY_STORE: 567 /* 568 * Unimplemented. I don't know of any file systems 569 * that use them, and the protocol isn't sound anyway, 570 * since the notification messages don't include the 571 * inode's generation number. Without that, it's 572 * possible to manipulate the cache of the wrong vnode. 573 * Finally, it's not defined what this message should 574 * do for a file with dirty cache. 575 */ 576 case FUSE_NOTIFY_POLL: 577 /* Unimplemented. See comments in fuse_vnops */ 578 default: 579 /* Not implemented */ 580 err = EXTERROR(ENOSYS, "Unimplemented FUSE notification code", 581 ohead.error); 582 } 583 vfs_unbusy(mp); 584 } else { 585 /* no callback at all! */ 586 SDT_PROBE1(fusefs, , device, fuse_device_write_missing_ticket, 587 ohead.unique); 588 if (ohead.error == -EAGAIN) { 589 /* 590 * This was probably a response to a FUSE_INTERRUPT 591 * operation whose original operation is already 592 * complete. We can't store FUSE_INTERRUPT tickets 593 * indefinitely because their responses are optional. 594 * So we delete them when the original operation 595 * completes. And sadly the fuse_header_out doesn't 596 * identify the opcode, so we have to guess. 597 */ 598 err = 0; 599 } else { 600 err = EXTERROR(EINVAL, "FUSE ticket is missing"); 601 } 602 } 603 604 return (err); 605 } 606 607 int 608 fuse_device_init(void) 609 { 610 611 fuse_dev = make_dev(&fuse_device_cdevsw, 0, UID_ROOT, GID_OPERATOR, 612 S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH, "fuse"); 613 if (fuse_dev == NULL) 614 return (ENOMEM); 615 return (0); 616 } 617 618 void 619 fuse_device_destroy(void) 620 { 621 622 MPASS(fuse_dev != NULL); 623 destroy_dev(fuse_dev); 624 } 625