fuse_vfsops.c revision 242875
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: head/sys/fs/fuse/fuse_vfsops.c 242875 2012-11-10 19:32:16Z attilio $"); 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/capability.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 104static vfs_mount_t fuse_vfsop_mount; 105static vfs_unmount_t fuse_vfsop_unmount; 106static vfs_root_t fuse_vfsop_root; 107static vfs_statfs_t fuse_vfsop_statfs; 108 109struct 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 116SYSCTL_INT(_vfs_fuse, OID_AUTO, init_backgrounded, CTLFLAG_RD, 117 0, 1, "indicate async handshake"); 118static int fuse_enforce_dev_perms = 0; 119 120SYSCTL_LONG(_vfs_fuse, OID_AUTO, enforce_dev_perms, CTLFLAG_RW, 121 &fuse_enforce_dev_perms, 0, 122 "enforce fuse device permissions for secondary mounts"); 123static unsigned sync_unmount = 1; 124 125SYSCTL_UINT(_vfs_fuse, OID_AUTO, sync_unmount, CTLFLAG_RW, 126 &sync_unmount, 0, "specify when to use synchronous unmount"); 127 128MALLOC_DEFINE(M_FUSEVFS, "fuse_filesystem", "buffer for fuse vfs layer"); 129 130static int 131fuse_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 204static int 205fuse_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; 223 224 subtype = NULL; 225 max_read_set = 0; 226 max_read = ~0; 227 err = 0; 228 mntopts = 0; 229 __mntopts = 0; 230 td = curthread; 231 232 fuse_trace_printf_vfsop(); 233 234 if (mp->mnt_flag & MNT_UPDATE) 235 return EOPNOTSUPP; 236 237 MNT_ILOCK(mp); 238 mp->mnt_flag |= MNT_SYNCHRONOUS; 239 mp->mnt_data = NULL; 240 MNT_IUNLOCK(mp); 241 /* Get the new options passed to mount */ 242 opts = mp->mnt_optnew; 243 244 if (!opts) 245 return EINVAL; 246 247 /* `fspath' contains the mount point (eg. /mnt/fuse/sshfs); REQUIRED */ 248 if (!vfs_getopts(opts, "fspath", &err)) 249 return err; 250 251 /* `from' contains the device name (eg. /dev/fuse0); REQUIRED */ 252 fspec = vfs_getopts(opts, "from", &err); 253 if (!fspec) 254 return err; 255 256 /* `fd' contains the filedescriptor for this session; REQUIRED */ 257 if (vfs_scanopt(opts, "fd", "%d", &fd) != 1) 258 return EINVAL; 259 260 err = fuse_getdevice(fspec, td, &fdev); 261 if (err != 0) 262 return err; 263 264 /* 265 * With the help of underscored options the mount program 266 * can inform us from the flags it sets by default 267 */ 268 FUSE_FLAGOPT(allow_other, FSESS_DAEMON_CAN_SPY); 269 FUSE_FLAGOPT(push_symlinks_in, FSESS_PUSH_SYMLINKS_IN); 270 FUSE_FLAGOPT(default_permissions, FSESS_DEFAULT_PERMISSIONS); 271 FUSE_FLAGOPT(no_attrcache, FSESS_NO_ATTRCACHE); 272 FUSE_FLAGOPT(no_readahed, FSESS_NO_READAHEAD); 273 FUSE_FLAGOPT(no_datacache, FSESS_NO_DATACACHE); 274 FUSE_FLAGOPT(no_namecache, FSESS_NO_NAMECACHE); 275 FUSE_FLAGOPT(no_mmap, FSESS_NO_MMAP); 276 FUSE_FLAGOPT(brokenio, FSESS_BROKENIO); 277 278 if (vfs_scanopt(opts, "max_read=", "%u", &max_read) == 1) 279 max_read_set = 1; 280 if (vfs_scanopt(opts, "timeout=", "%u", &daemon_timeout) == 1) { 281 if (daemon_timeout < FUSE_MIN_DAEMON_TIMEOUT) 282 daemon_timeout = FUSE_MIN_DAEMON_TIMEOUT; 283 else if (daemon_timeout > FUSE_MAX_DAEMON_TIMEOUT) 284 daemon_timeout = FUSE_MAX_DAEMON_TIMEOUT; 285 } else { 286 daemon_timeout = FUSE_DEFAULT_DAEMON_TIMEOUT; 287 } 288 subtype = vfs_getopts(opts, "subtype=", &err); 289 290 FS_DEBUG2G("mntopts 0x%jx\n", (uintmax_t)mntopts); 291 292 err = fget(td, fd, CAP_READ, &fp); 293 if (err != 0) { 294 FS_DEBUG("invalid or not opened device: data=%p\n", data); 295 goto out; 296 } 297 fptmp = td->td_fpop; 298 td->td_fpop = fp; 299 err = devfs_get_cdevpriv((void **)&data); 300 td->td_fpop = fptmp; 301 fdrop(fp, td); 302 FUSE_LOCK(); 303 if (err != 0 || data == NULL || data->mp != NULL) { 304 FS_DEBUG("invalid or not opened device: data=%p data.mp=%p\n", 305 data, data != NULL ? data->mp : NULL); 306 err = ENXIO; 307 FUSE_UNLOCK(); 308 goto out; 309 } 310 if (fdata_get_dead(data)) { 311 FS_DEBUG("device is dead during mount: data=%p\n", data); 312 err = ENOTCONN; 313 FUSE_UNLOCK(); 314 goto out; 315 } 316 /* Sanity + permission checks */ 317 if (!data->daemoncred) 318 panic("fuse daemon found, but identity unknown"); 319 if (mntopts & FSESS_DAEMON_CAN_SPY) 320 err = priv_check(td, PRIV_VFS_FUSE_ALLOWOTHER); 321 if (err == 0 && td->td_ucred->cr_uid != data->daemoncred->cr_uid) 322 /* are we allowed to do the first mount? */ 323 err = priv_check(td, PRIV_VFS_FUSE_MOUNT_NONUSER); 324 if (err) { 325 FUSE_UNLOCK(); 326 goto out; 327 } 328 data->ref++; 329 data->mp = mp; 330 data->dataflags |= mntopts; 331 data->max_read = max_read; 332 data->daemon_timeout = daemon_timeout; 333 FUSE_UNLOCK(); 334 335 vfs_getnewfsid(mp); 336 MNT_ILOCK(mp); 337 mp->mnt_data = data; 338 mp->mnt_flag |= MNT_LOCAL; 339 MNT_IUNLOCK(mp); 340 /* We need this here as this slot is used by getnewvnode() */ 341 mp->mnt_stat.f_iosize = PAGE_SIZE; 342 if (subtype) { 343 strlcat(mp->mnt_stat.f_fstypename, ".", MFSNAMELEN); 344 strlcat(mp->mnt_stat.f_fstypename, subtype, MFSNAMELEN); 345 } 346 copystr(fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &len); 347 bzero(mp->mnt_stat.f_mntfromname + len, MNAMELEN - len); 348 FS_DEBUG2G("mp %p: %s\n", mp, mp->mnt_stat.f_mntfromname); 349 350 /* Now handshaking with daemon */ 351 fuse_internal_send_init(data, td); 352 353out: 354 if (err) { 355 FUSE_LOCK(); 356 if (data->mp == mp) { 357 /* 358 * Destroy device only if we acquired reference to 359 * it 360 */ 361 FS_DEBUG("mount failed, destroy device: data=%p mp=%p" 362 " err=%d\n", 363 data, mp, err); 364 data->mp = NULL; 365 fdata_trydestroy(data); 366 } 367 FUSE_UNLOCK(); 368 dev_rel(fdev); 369 } 370 return err; 371} 372 373static int 374fuse_vfsop_unmount(struct mount *mp, int mntflags) 375{ 376 int err = 0; 377 int flags = 0; 378 379 struct cdev *fdev; 380 struct fuse_data *data; 381 struct fuse_dispatcher fdi; 382 struct thread *td = curthread; 383 384 fuse_trace_printf_vfsop(); 385 386 if (mntflags & MNT_FORCE) { 387 flags |= FORCECLOSE; 388 } 389 data = fuse_get_mpdata(mp); 390 if (!data) { 391 panic("no private data for mount point?"); 392 } 393 /* There is 1 extra root vnode reference (mp->mnt_data). */ 394 FUSE_LOCK(); 395 if (data->vroot != NULL) { 396 struct vnode *vroot = data->vroot; 397 398 data->vroot = NULL; 399 FUSE_UNLOCK(); 400 vrele(vroot); 401 } else 402 FUSE_UNLOCK(); 403 err = vflush(mp, 0, flags, td); 404 if (err) { 405 debug_printf("vflush failed"); 406 return err; 407 } 408 if (fdata_get_dead(data)) { 409 goto alreadydead; 410 } 411 fdisp_init(&fdi, 0); 412 fdisp_make(&fdi, FUSE_DESTROY, mp, 0, td, NULL); 413 414 err = fdisp_wait_answ(&fdi); 415 fdisp_destroy(&fdi); 416 417 fdata_set_dead(data); 418 419alreadydead: 420 FUSE_LOCK(); 421 data->mp = NULL; 422 fdev = data->fdev; 423 fdata_trydestroy(data); 424 FUSE_UNLOCK(); 425 426 MNT_ILOCK(mp); 427 mp->mnt_data = NULL; 428 mp->mnt_flag &= ~MNT_LOCAL; 429 MNT_IUNLOCK(mp); 430 431 dev_rel(fdev); 432 433 return 0; 434} 435 436static int 437fuse_vfsop_root(struct mount *mp, int lkflags, struct vnode **vpp) 438{ 439 struct fuse_data *data = fuse_get_mpdata(mp); 440 int err = 0; 441 442 if (data->vroot != NULL) { 443 err = vget(data->vroot, lkflags, curthread); 444 if (err == 0) 445 *vpp = data->vroot; 446 } else { 447 err = fuse_vnode_get(mp, FUSE_ROOT_ID, NULL, vpp, NULL, VDIR); 448 if (err == 0) { 449 FUSE_LOCK(); 450 MPASS(data->vroot == NULL || data->vroot == *vpp); 451 if (data->vroot == NULL) { 452 FS_DEBUG("new root vnode\n"); 453 data->vroot = *vpp; 454 FUSE_UNLOCK(); 455 vref(*vpp); 456 } else if (data->vroot != *vpp) { 457 FS_DEBUG("root vnode race\n"); 458 FUSE_UNLOCK(); 459 VOP_UNLOCK(*vpp, 0); 460 vrele(*vpp); 461 vrecycle(*vpp); 462 *vpp = data->vroot; 463 } else 464 FUSE_UNLOCK(); 465 } 466 } 467 return err; 468} 469 470static int 471fuse_vfsop_statfs(struct mount *mp, struct statfs *sbp) 472{ 473 struct fuse_dispatcher fdi; 474 int err = 0; 475 476 struct fuse_statfs_out *fsfo; 477 struct fuse_data *data; 478 479 FS_DEBUG2G("mp %p: %s\n", mp, mp->mnt_stat.f_mntfromname); 480 data = fuse_get_mpdata(mp); 481 482 if (!(data->dataflags & FSESS_INITED)) 483 goto fake; 484 485 fdisp_init(&fdi, 0); 486 fdisp_make(&fdi, FUSE_STATFS, mp, FUSE_ROOT_ID, NULL, NULL); 487 err = fdisp_wait_answ(&fdi); 488 if (err) { 489 fdisp_destroy(&fdi); 490 if (err == ENOTCONN) { 491 /* 492 * We want to seem a legitimate fs even if the daemon 493 * is stiff dead... (so that, eg., we can still do path 494 * based unmounting after the daemon dies). 495 */ 496 goto fake; 497 } 498 return err; 499 } 500 fsfo = fdi.answ; 501 502 sbp->f_blocks = fsfo->st.blocks; 503 sbp->f_bfree = fsfo->st.bfree; 504 sbp->f_bavail = fsfo->st.bavail; 505 sbp->f_files = fsfo->st.files; 506 sbp->f_ffree = fsfo->st.ffree; /* cast from uint64_t to int64_t */ 507 sbp->f_namemax = fsfo->st.namelen; 508 sbp->f_bsize = fsfo->st.frsize; /* cast from uint32_t to uint64_t */ 509 510 FS_DEBUG("fuse_statfs_out -- blocks: %llu, bfree: %llu, bavail: %llu, " 511 "fil es: %llu, ffree: %llu, bsize: %i, namelen: %i\n", 512 (unsigned long long)fsfo->st.blocks, 513 (unsigned long long)fsfo->st.bfree, 514 (unsigned long long)fsfo->st.bavail, 515 (unsigned long long)fsfo->st.files, 516 (unsigned long long)fsfo->st.ffree, fsfo->st.bsize, 517 fsfo->st.namelen); 518 519 fdisp_destroy(&fdi); 520 return 0; 521 522fake: 523 sbp->f_blocks = 0; 524 sbp->f_bfree = 0; 525 sbp->f_bavail = 0; 526 sbp->f_files = 0; 527 sbp->f_ffree = 0; 528 sbp->f_namemax = 0; 529 sbp->f_bsize = FUSE_DEFAULT_BLOCKSIZE; 530 531 return 0; 532} 533