Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/fs/fuse/fuse_vfsops.c
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1 /* 2 * Copyright (c) 2007-2009 Google Inc. and Amit Singh 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: 8 * 9 * * Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * * Redistributions in binary form must reproduce the above 12 * copyright notice, this list of conditions and the following disclaimer 13 * in the documentation and/or other materials provided with the 14 * distribution. 15 * * Neither the name of Google Inc. nor the names of its 16 * contributors may be used to endorse or promote products derived from 17 * this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 * 31 * Copyright (C) 2005 Csaba Henk. 32 * All rights reserved. 33 * 34 * Redistribution and use in source and binary forms, with or without 35 * modification, are permitted provided that the following conditions 36 * are met: 37 * 1. Redistributions of source code must retain the above copyright 38 * notice, this list of conditions and the following disclaimer. 39 * 2. Redistributions in binary form must reproduce the above copyright 40 * notice, this list of conditions and the following disclaimer in the 41 * documentation and/or other materials provided with the distribution. 42 * 43 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 44 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 45 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 46 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 47 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 48 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 49 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 50 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 51 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 52 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 53 * SUCH DAMAGE. 54 */ 55 56 #include <sys/cdefs.h> 57 __FBSDID("$FreeBSD: releng/10.4/sys/fs/fuse/fuse_vfsops.c 282270 2015-04-30 12:39:24Z rmacklem $"); 58 59 #include <sys/types.h> 60 #include <sys/module.h> 61 #include <sys/systm.h> 62 #include <sys/errno.h> 63 #include <sys/param.h> 64 #include <sys/kernel.h> 65 #include <sys/capsicum.h> 66 #include <sys/conf.h> 67 #include <sys/filedesc.h> 68 #include <sys/uio.h> 69 #include <sys/malloc.h> 70 #include <sys/queue.h> 71 #include <sys/lock.h> 72 #include <sys/sx.h> 73 #include <sys/mutex.h> 74 #include <sys/proc.h> 75 #include <sys/vnode.h> 76 #include <sys/namei.h> 77 #include <sys/mount.h> 78 #include <sys/sysctl.h> 79 #include <sys/fcntl.h> 80 81 #include "fuse.h" 82 #include "fuse_param.h" 83 #include "fuse_node.h" 84 #include "fuse_ipc.h" 85 #include "fuse_internal.h" 86 87 #include <sys/priv.h> 88 #include <security/mac/mac_framework.h> 89 90 #define FUSE_DEBUG_MODULE VFSOPS 91 #include "fuse_debug.h" 92 93 /* This will do for privilege types for now */ 94 #ifndef PRIV_VFS_FUSE_ALLOWOTHER 95 #define PRIV_VFS_FUSE_ALLOWOTHER PRIV_VFS_MOUNT_NONUSER 96 #endif 97 #ifndef PRIV_VFS_FUSE_MOUNT_NONUSER 98 #define PRIV_VFS_FUSE_MOUNT_NONUSER PRIV_VFS_MOUNT_NONUSER 99 #endif 100 #ifndef PRIV_VFS_FUSE_SYNC_UNMOUNT 101 #define PRIV_VFS_FUSE_SYNC_UNMOUNT PRIV_VFS_MOUNT_NONUSER 102 #endif 103 104 static vfs_mount_t fuse_vfsop_mount; 105 static vfs_unmount_t fuse_vfsop_unmount; 106 static vfs_root_t fuse_vfsop_root; 107 static vfs_statfs_t fuse_vfsop_statfs; 108 109 struct vfsops fuse_vfsops = { 110 .vfs_mount = fuse_vfsop_mount, 111 .vfs_unmount = fuse_vfsop_unmount, 112 .vfs_root = fuse_vfsop_root, 113 .vfs_statfs = fuse_vfsop_statfs, 114 }; 115 116 SYSCTL_INT(_vfs_fuse, OID_AUTO, init_backgrounded, CTLFLAG_RD, 117 SYSCTL_NULL_INT_PTR, 1, "indicate async handshake"); 118 static int fuse_enforce_dev_perms = 0; 119 120 SYSCTL_INT(_vfs_fuse, OID_AUTO, enforce_dev_perms, CTLFLAG_RW, 121 &fuse_enforce_dev_perms, 0, 122 "enforce fuse device permissions for secondary mounts"); 123 static unsigned sync_unmount = 1; 124 125 SYSCTL_UINT(_vfs_fuse, OID_AUTO, sync_unmount, CTLFLAG_RW, 126 &sync_unmount, 0, "specify when to use synchronous unmount"); 127 128 MALLOC_DEFINE(M_FUSEVFS, "fuse_filesystem", "buffer for fuse vfs layer"); 129 130 static int 131 fuse_getdevice(const char *fspec, struct thread *td, struct cdev **fdevp) 132 { 133 struct nameidata nd, *ndp = &nd; 134 struct vnode *devvp; 135 struct cdev *fdev; 136 int err; 137 138 /* 139 * Not an update, or updating the name: look up the name 140 * and verify that it refers to a sensible disk device. 141 */ 142 143 NDINIT(ndp, LOOKUP, FOLLOW, UIO_SYSSPACE, fspec, td); 144 if ((err = namei(ndp)) != 0) 145 return err; 146 NDFREE(ndp, NDF_ONLY_PNBUF); 147 devvp = ndp->ni_vp; 148 149 if (devvp->v_type != VCHR) { 150 vrele(devvp); 151 return ENXIO; 152 } 153 fdev = devvp->v_rdev; 154 dev_ref(fdev); 155 156 if (fuse_enforce_dev_perms) { 157 /* 158 * Check if mounter can open the fuse device. 159 * 160 * This has significance only if we are doing a secondary mount 161 * which doesn't involve actually opening fuse devices, but we 162 * still want to enforce the permissions of the device (in 163 * order to keep control over the circle of fuse users). 164 * 165 * (In case of primary mounts, we are either the superuser so 166 * we can do anything anyway, or we can mount only if the 167 * device is already opened by us, ie. we are permitted to open 168 * the device.) 169 */ 170 #if 0 171 #ifdef MAC 172 err = mac_check_vnode_open(td->td_ucred, devvp, VREAD | VWRITE); 173 if (!err) 174 #endif 175 #endif /* 0 */ 176 err = VOP_ACCESS(devvp, VREAD | VWRITE, td->td_ucred, td); 177 if (err) { 178 vrele(devvp); 179 dev_rel(fdev); 180 return err; 181 } 182 } 183 /* 184 * according to coda code, no extra lock is needed -- 185 * although in sys/vnode.h this field is marked "v" 186 */ 187 vrele(devvp); 188 189 if (!fdev->si_devsw || 190 strcmp("fuse", fdev->si_devsw->d_name)) { 191 dev_rel(fdev); 192 return ENXIO; 193 } 194 *fdevp = fdev; 195 196 return 0; 197 } 198 199 #define FUSE_FLAGOPT(fnam, fval) do { \ 200 vfs_flagopt(opts, #fnam, &mntopts, fval); \ 201 vfs_flagopt(opts, "__" #fnam, &__mntopts, fval); \ 202 } while (0) 203 204 static int 205 fuse_vfsop_mount(struct mount *mp) 206 { 207 int err; 208 209 uint64_t mntopts, __mntopts; 210 int max_read_set; 211 uint32_t max_read; 212 int daemon_timeout; 213 int fd; 214 215 size_t len; 216 217 struct cdev *fdev; 218 struct fuse_data *data; 219 struct thread *td; 220 struct file *fp, *fptmp; 221 char *fspec, *subtype; 222 struct vfsoptlist *opts; 223 cap_rights_t rights; 224 225 subtype = NULL; 226 max_read_set = 0; 227 max_read = ~0; 228 err = 0; 229 mntopts = 0; 230 __mntopts = 0; 231 td = curthread; 232 233 fuse_trace_printf_vfsop(); 234 235 if (mp->mnt_flag & MNT_UPDATE) 236 return EOPNOTSUPP; 237 238 MNT_ILOCK(mp); 239 mp->mnt_flag |= MNT_SYNCHRONOUS; 240 mp->mnt_data = NULL; 241 MNT_IUNLOCK(mp); 242 /* Get the new options passed to mount */ 243 opts = mp->mnt_optnew; 244 245 if (!opts) 246 return EINVAL; 247 248 /* `fspath' contains the mount point (eg. /mnt/fuse/sshfs); REQUIRED */ 249 if (!vfs_getopts(opts, "fspath", &err)) 250 return err; 251 252 /* `from' contains the device name (eg. /dev/fuse0); REQUIRED */ 253 fspec = vfs_getopts(opts, "from", &err); 254 if (!fspec) 255 return err; 256 257 /* `fd' contains the filedescriptor for this session; REQUIRED */ 258 if (vfs_scanopt(opts, "fd", "%d", &fd) != 1) 259 return EINVAL; 260 261 err = fuse_getdevice(fspec, td, &fdev); 262 if (err != 0) 263 return err; 264 265 /* 266 * With the help of underscored options the mount program 267 * can inform us from the flags it sets by default 268 */ 269 FUSE_FLAGOPT(allow_other, FSESS_DAEMON_CAN_SPY); 270 FUSE_FLAGOPT(push_symlinks_in, FSESS_PUSH_SYMLINKS_IN); 271 FUSE_FLAGOPT(default_permissions, FSESS_DEFAULT_PERMISSIONS); 272 FUSE_FLAGOPT(no_attrcache, FSESS_NO_ATTRCACHE); 273 FUSE_FLAGOPT(no_readahed, FSESS_NO_READAHEAD); 274 FUSE_FLAGOPT(no_datacache, FSESS_NO_DATACACHE); 275 FUSE_FLAGOPT(no_namecache, FSESS_NO_NAMECACHE); 276 FUSE_FLAGOPT(no_mmap, FSESS_NO_MMAP); 277 FUSE_FLAGOPT(brokenio, FSESS_BROKENIO); 278 279 if (vfs_scanopt(opts, "max_read=", "%u", &max_read) == 1) 280 max_read_set = 1; 281 if (vfs_scanopt(opts, "timeout=", "%u", &daemon_timeout) == 1) { 282 if (daemon_timeout < FUSE_MIN_DAEMON_TIMEOUT) 283 daemon_timeout = FUSE_MIN_DAEMON_TIMEOUT; 284 else if (daemon_timeout > FUSE_MAX_DAEMON_TIMEOUT) 285 daemon_timeout = FUSE_MAX_DAEMON_TIMEOUT; 286 } else { 287 daemon_timeout = FUSE_DEFAULT_DAEMON_TIMEOUT; 288 } 289 subtype = vfs_getopts(opts, "subtype=", &err); 290 291 FS_DEBUG2G("mntopts 0x%jx\n", (uintmax_t)mntopts); 292 293 err = fget(td, fd, cap_rights_init(&rights, CAP_READ), &fp); 294 if (err != 0) { 295 FS_DEBUG("invalid or not opened device: data=%p\n", data); 296 goto out; 297 } 298 fptmp = td->td_fpop; 299 td->td_fpop = fp; 300 err = devfs_get_cdevpriv((void **)&data); 301 td->td_fpop = fptmp; 302 fdrop(fp, td); 303 FUSE_LOCK(); 304 if (err != 0 || data == NULL || data->mp != NULL) { 305 FS_DEBUG("invalid or not opened device: data=%p data.mp=%p\n", 306 data, data != NULL ? data->mp : NULL); 307 err = ENXIO; 308 FUSE_UNLOCK(); 309 goto out; 310 } 311 if (fdata_get_dead(data)) { 312 FS_DEBUG("device is dead during mount: data=%p\n", data); 313 err = ENOTCONN; 314 FUSE_UNLOCK(); 315 goto out; 316 } 317 /* Sanity + permission checks */ 318 if (!data->daemoncred) 319 panic("fuse daemon found, but identity unknown"); 320 if (mntopts & FSESS_DAEMON_CAN_SPY) 321 err = priv_check(td, PRIV_VFS_FUSE_ALLOWOTHER); 322 if (err == 0 && td->td_ucred->cr_uid != data->daemoncred->cr_uid) 323 /* are we allowed to do the first mount? */ 324 err = priv_check(td, PRIV_VFS_FUSE_MOUNT_NONUSER); 325 if (err) { 326 FUSE_UNLOCK(); 327 goto out; 328 } 329 data->ref++; 330 data->mp = mp; 331 data->dataflags |= mntopts; 332 data->max_read = max_read; 333 data->daemon_timeout = daemon_timeout; 334 FUSE_UNLOCK(); 335 336 vfs_getnewfsid(mp); 337 MNT_ILOCK(mp); 338 mp->mnt_data = data; 339 mp->mnt_flag |= MNT_LOCAL; 340 mp->mnt_kern_flag |= MNTK_USES_BCACHE; 341 MNT_IUNLOCK(mp); 342 /* We need this here as this slot is used by getnewvnode() */ 343 mp->mnt_stat.f_iosize = PAGE_SIZE; 344 if (subtype) { 345 strlcat(mp->mnt_stat.f_fstypename, ".", MFSNAMELEN); 346 strlcat(mp->mnt_stat.f_fstypename, subtype, MFSNAMELEN); 347 } 348 copystr(fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &len); 349 bzero(mp->mnt_stat.f_mntfromname + len, MNAMELEN - len); 350 FS_DEBUG2G("mp %p: %s\n", mp, mp->mnt_stat.f_mntfromname); 351 352 /* Now handshaking with daemon */ 353 fuse_internal_send_init(data, td); 354 355 out: 356 if (err) { 357 FUSE_LOCK(); 358 if (data->mp == mp) { 359 /* 360 * Destroy device only if we acquired reference to 361 * it 362 */ 363 FS_DEBUG("mount failed, destroy device: data=%p mp=%p" 364 " err=%d\n", 365 data, mp, err); 366 data->mp = NULL; 367 fdata_trydestroy(data); 368 } 369 FUSE_UNLOCK(); 370 dev_rel(fdev); 371 } 372 return err; 373 } 374 375 static int 376 fuse_vfsop_unmount(struct mount *mp, int mntflags) 377 { 378 int err = 0; 379 int flags = 0; 380 381 struct cdev *fdev; 382 struct fuse_data *data; 383 struct fuse_dispatcher fdi; 384 struct thread *td = curthread; 385 386 fuse_trace_printf_vfsop(); 387 388 if (mntflags & MNT_FORCE) { 389 flags |= FORCECLOSE; 390 } 391 data = fuse_get_mpdata(mp); 392 if (!data) { 393 panic("no private data for mount point?"); 394 } 395 /* There is 1 extra root vnode reference (mp->mnt_data). */ 396 FUSE_LOCK(); 397 if (data->vroot != NULL) { 398 struct vnode *vroot = data->vroot; 399 400 data->vroot = NULL; 401 FUSE_UNLOCK(); 402 vrele(vroot); 403 } else 404 FUSE_UNLOCK(); 405 err = vflush(mp, 0, flags, td); 406 if (err) { 407 debug_printf("vflush failed"); 408 return err; 409 } 410 if (fdata_get_dead(data)) { 411 goto alreadydead; 412 } 413 fdisp_init(&fdi, 0); 414 fdisp_make(&fdi, FUSE_DESTROY, mp, 0, td, NULL); 415 416 err = fdisp_wait_answ(&fdi); 417 fdisp_destroy(&fdi); 418 419 fdata_set_dead(data); 420 421 alreadydead: 422 FUSE_LOCK(); 423 data->mp = NULL; 424 fdev = data->fdev; 425 fdata_trydestroy(data); 426 FUSE_UNLOCK(); 427 428 MNT_ILOCK(mp); 429 mp->mnt_data = NULL; 430 mp->mnt_flag &= ~MNT_LOCAL; 431 MNT_IUNLOCK(mp); 432 433 dev_rel(fdev); 434 435 return 0; 436 } 437 438 static int 439 fuse_vfsop_root(struct mount *mp, int lkflags, struct vnode **vpp) 440 { 441 struct fuse_data *data = fuse_get_mpdata(mp); 442 int err = 0; 443 444 if (data->vroot != NULL) { 445 err = vget(data->vroot, lkflags, curthread); 446 if (err == 0) 447 *vpp = data->vroot; 448 } else { 449 err = fuse_vnode_get(mp, FUSE_ROOT_ID, NULL, vpp, NULL, VDIR); 450 if (err == 0) { 451 FUSE_LOCK(); 452 MPASS(data->vroot == NULL || data->vroot == *vpp); 453 if (data->vroot == NULL) { 454 FS_DEBUG("new root vnode\n"); 455 data->vroot = *vpp; 456 FUSE_UNLOCK(); 457 vref(*vpp); 458 } else if (data->vroot != *vpp) { 459 FS_DEBUG("root vnode race\n"); 460 FUSE_UNLOCK(); 461 VOP_UNLOCK(*vpp, 0); 462 vrele(*vpp); 463 vrecycle(*vpp); 464 *vpp = data->vroot; 465 } else 466 FUSE_UNLOCK(); 467 } 468 } 469 return err; 470 } 471 472 static int 473 fuse_vfsop_statfs(struct mount *mp, struct statfs *sbp) 474 { 475 struct fuse_dispatcher fdi; 476 int err = 0; 477 478 struct fuse_statfs_out *fsfo; 479 struct fuse_data *data; 480 481 FS_DEBUG2G("mp %p: %s\n", mp, mp->mnt_stat.f_mntfromname); 482 data = fuse_get_mpdata(mp); 483 484 if (!(data->dataflags & FSESS_INITED)) 485 goto fake; 486 487 fdisp_init(&fdi, 0); 488 fdisp_make(&fdi, FUSE_STATFS, mp, FUSE_ROOT_ID, NULL, NULL); 489 err = fdisp_wait_answ(&fdi); 490 if (err) { 491 fdisp_destroy(&fdi); 492 if (err == ENOTCONN) { 493 /* 494 * We want to seem a legitimate fs even if the daemon 495 * is stiff dead... (so that, eg., we can still do path 496 * based unmounting after the daemon dies). 497 */ 498 goto fake; 499 } 500 return err; 501 } 502 fsfo = fdi.answ; 503 504 sbp->f_blocks = fsfo->st.blocks; 505 sbp->f_bfree = fsfo->st.bfree; 506 sbp->f_bavail = fsfo->st.bavail; 507 sbp->f_files = fsfo->st.files; 508 sbp->f_ffree = fsfo->st.ffree; /* cast from uint64_t to int64_t */ 509 sbp->f_namemax = fsfo->st.namelen; 510 sbp->f_bsize = fsfo->st.frsize; /* cast from uint32_t to uint64_t */ 511 512 FS_DEBUG("fuse_statfs_out -- blocks: %llu, bfree: %llu, bavail: %llu, " 513 "fil es: %llu, ffree: %llu, bsize: %i, namelen: %i\n", 514 (unsigned long long)fsfo->st.blocks, 515 (unsigned long long)fsfo->st.bfree, 516 (unsigned long long)fsfo->st.bavail, 517 (unsigned long long)fsfo->st.files, 518 (unsigned long long)fsfo->st.ffree, fsfo->st.bsize, 519 fsfo->st.namelen); 520 521 fdisp_destroy(&fdi); 522 return 0; 523 524 fake: 525 sbp->f_blocks = 0; 526 sbp->f_bfree = 0; 527 sbp->f_bavail = 0; 528 sbp->f_files = 0; 529 sbp->f_ffree = 0; 530 sbp->f_namemax = 0; 531 sbp->f_bsize = FUSE_DEFAULT_BLOCKSIZE; 532 533 return 0; 534 }
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