1/* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include <stdio.h> 18#include <stdlib.h> 19#include <string.h> 20#include <unistd.h> 21#include <errno.h> 22#include <fcntl.h> 23#include <sys/mount.h> 24#include <sys/stat.h> 25#include <sys/statfs.h> 26#include <sys/uio.h> 27#include <dirent.h> 28#include <limits.h> 29#include <ctype.h> 30#include <pthread.h> 31 32#include <private/android_filesystem_config.h> 33 34#include "fuse.h" 35 36/* README 37 * 38 * What is this? 39 * 40 * sdcard is a program that uses FUSE to emulate FAT-on-sdcard style 41 * directory permissions (all files are given fixed owner, group, and 42 * permissions at creation, owner, group, and permissions are not 43 * changeable, symlinks and hardlinks are not createable, etc. 44 * 45 * See usage() for command line options. 46 * 47 * It must be run as root, but will drop to requested UID/GID as soon as it 48 * mounts a filesystem. It will refuse to run if requested UID/GID are zero. 49 * 50 * Things I believe to be true: 51 * 52 * - ops that return a fuse_entry (LOOKUP, MKNOD, MKDIR, LINK, SYMLINK, 53 * CREAT) must bump that node's refcount 54 * - don't forget that FORGET can forget multiple references (req->nlookup) 55 * - if an op that returns a fuse_entry fails writing the reply to the 56 * kernel, you must rollback the refcount to reflect the reference the 57 * kernel did not actually acquire 58 */ 59 60#define FUSE_TRACE 0 61 62#if FUSE_TRACE 63#define TRACE(x...) fprintf(stderr,x) 64#else 65#define TRACE(x...) do {} while (0) 66#endif 67 68#define ERROR(x...) fprintf(stderr,x) 69 70#define FUSE_UNKNOWN_INO 0xffffffff 71 72/* Maximum number of bytes to write in one request. */ 73#define MAX_WRITE (256 * 1024) 74 75/* Maximum number of bytes to read in one request. */ 76#define MAX_READ (128 * 1024) 77 78/* Largest possible request. 79 * The request size is bounded by the maximum size of a FUSE_WRITE request because it has 80 * the largest possible data payload. */ 81#define MAX_REQUEST_SIZE (sizeof(struct fuse_in_header) + sizeof(struct fuse_write_in) + MAX_WRITE) 82 83/* Default number of threads. */ 84#define DEFAULT_NUM_THREADS 2 85 86/* Pseudo-error constant used to indicate that no fuse status is needed 87 * or that a reply has already been written. */ 88#define NO_STATUS 1 89 90struct handle { 91 int fd; 92}; 93 94struct dirhandle { 95 DIR *d; 96}; 97 98struct node { 99 __u32 refcount; 100 __u64 nid; 101 __u64 gen; 102 103 struct node *next; /* per-dir sibling list */ 104 struct node *child; /* first contained file by this dir */ 105 struct node *parent; /* containing directory */ 106 107 size_t namelen; 108 char *name; 109 /* If non-null, this is the real name of the file in the underlying storage. 110 * This may differ from the field "name" only by case. 111 * strlen(actual_name) will always equal strlen(name), so it is safe to use 112 * namelen for both fields. 113 */ 114 char *actual_name; 115}; 116 117/* Global data structure shared by all fuse handlers. */ 118struct fuse { 119 pthread_mutex_t lock; 120 121 __u64 next_generation; 122 int fd; 123 struct node root; 124 char rootpath[PATH_MAX]; 125}; 126 127/* Private data used by a single fuse handler. */ 128struct fuse_handler { 129 struct fuse* fuse; 130 int token; 131 132 /* To save memory, we never use the contents of the request buffer and the read 133 * buffer at the same time. This allows us to share the underlying storage. */ 134 union { 135 __u8 request_buffer[MAX_REQUEST_SIZE]; 136 __u8 read_buffer[MAX_READ]; 137 }; 138}; 139 140static inline void *id_to_ptr(__u64 nid) 141{ 142 return (void *) (uintptr_t) nid; 143} 144 145static inline __u64 ptr_to_id(void *ptr) 146{ 147 return (__u64) (uintptr_t) ptr; 148} 149 150static void acquire_node_locked(struct node* node) 151{ 152 node->refcount++; 153 TRACE("ACQUIRE %p (%s) rc=%d\n", node, node->name, node->refcount); 154} 155 156static void remove_node_from_parent_locked(struct node* node); 157 158static void release_node_locked(struct node* node) 159{ 160 TRACE("RELEASE %p (%s) rc=%d\n", node, node->name, node->refcount); 161 if (node->refcount > 0) { 162 node->refcount--; 163 if (!node->refcount) { 164 TRACE("DESTROY %p (%s)\n", node, node->name); 165 remove_node_from_parent_locked(node); 166 167 /* TODO: remove debugging - poison memory */ 168 memset(node->name, 0xef, node->namelen); 169 free(node->name); 170 free(node->actual_name); 171 memset(node, 0xfc, sizeof(*node)); 172 free(node); 173 } 174 } else { 175 ERROR("Zero refcnt %p\n", node); 176 } 177} 178 179static void add_node_to_parent_locked(struct node *node, struct node *parent) { 180 node->parent = parent; 181 node->next = parent->child; 182 parent->child = node; 183 acquire_node_locked(parent); 184} 185 186static void remove_node_from_parent_locked(struct node* node) 187{ 188 if (node->parent) { 189 if (node->parent->child == node) { 190 node->parent->child = node->parent->child->next; 191 } else { 192 struct node *node2; 193 node2 = node->parent->child; 194 while (node2->next != node) 195 node2 = node2->next; 196 node2->next = node->next; 197 } 198 release_node_locked(node->parent); 199 node->parent = NULL; 200 node->next = NULL; 201 } 202} 203 204/* Gets the absolute path to a node into the provided buffer. 205 * 206 * Populates 'buf' with the path and returns the length of the path on success, 207 * or returns -1 if the path is too long for the provided buffer. 208 */ 209static ssize_t get_node_path_locked(struct node* node, char* buf, size_t bufsize) 210{ 211 size_t namelen = node->namelen; 212 if (bufsize < namelen + 1) { 213 return -1; 214 } 215 216 ssize_t pathlen = 0; 217 if (node->parent) { 218 pathlen = get_node_path_locked(node->parent, buf, bufsize - namelen - 2); 219 if (pathlen < 0) { 220 return -1; 221 } 222 buf[pathlen++] = '/'; 223 } 224 225 const char* name = node->actual_name ? node->actual_name : node->name; 226 memcpy(buf + pathlen, name, namelen + 1); /* include trailing \0 */ 227 return pathlen + namelen; 228} 229 230/* Finds the absolute path of a file within a given directory. 231 * Performs a case-insensitive search for the file and sets the buffer to the path 232 * of the first matching file. If 'search' is zero or if no match is found, sets 233 * the buffer to the path that the file would have, assuming the name were case-sensitive. 234 * 235 * Populates 'buf' with the path and returns the actual name (within 'buf') on success, 236 * or returns NULL if the path is too long for the provided buffer. 237 */ 238static char* find_file_within(const char* path, const char* name, 239 char* buf, size_t bufsize, int search) 240{ 241 size_t pathlen = strlen(path); 242 size_t namelen = strlen(name); 243 size_t childlen = pathlen + namelen + 1; 244 char* actual; 245 246 if (bufsize <= childlen) { 247 return NULL; 248 } 249 250 memcpy(buf, path, pathlen); 251 buf[pathlen] = '/'; 252 actual = buf + pathlen + 1; 253 memcpy(actual, name, namelen + 1); 254 255 if (search && access(buf, F_OK)) { 256 struct dirent* entry; 257 DIR* dir = opendir(path); 258 if (!dir) { 259 ERROR("opendir %s failed: %s", path, strerror(errno)); 260 return actual; 261 } 262 while ((entry = readdir(dir))) { 263 if (!strcasecmp(entry->d_name, name)) { 264 /* we have a match - replace the name, don't need to copy the null again */ 265 memcpy(actual, entry->d_name, namelen); 266 break; 267 } 268 } 269 closedir(dir); 270 } 271 return actual; 272} 273 274static void attr_from_stat(struct fuse_attr *attr, const struct stat *s, __u64 nid) 275{ 276 attr->ino = nid; 277 attr->size = s->st_size; 278 attr->blocks = s->st_blocks; 279 attr->atime = s->st_atime; 280 attr->mtime = s->st_mtime; 281 attr->ctime = s->st_ctime; 282 attr->atimensec = s->st_atime_nsec; 283 attr->mtimensec = s->st_mtime_nsec; 284 attr->ctimensec = s->st_ctime_nsec; 285 attr->mode = s->st_mode; 286 attr->nlink = s->st_nlink; 287 288 /* force permissions to something reasonable: 289 * world readable 290 * writable by the sdcard group 291 */ 292 if (attr->mode & 0100) { 293 attr->mode = (attr->mode & (~0777)) | 0775; 294 } else { 295 attr->mode = (attr->mode & (~0777)) | 0664; 296 } 297 298 /* all files owned by root.sdcard */ 299 attr->uid = 0; 300 attr->gid = AID_SDCARD_RW; 301} 302 303struct node *create_node_locked(struct fuse* fuse, 304 struct node *parent, const char *name, const char* actual_name) 305{ 306 struct node *node; 307 size_t namelen = strlen(name); 308 309 node = calloc(1, sizeof(struct node)); 310 if (!node) { 311 return NULL; 312 } 313 node->name = malloc(namelen + 1); 314 if (!node->name) { 315 free(node); 316 return NULL; 317 } 318 memcpy(node->name, name, namelen + 1); 319 if (strcmp(name, actual_name)) { 320 node->actual_name = malloc(namelen + 1); 321 if (!node->actual_name) { 322 free(node->name); 323 free(node); 324 return NULL; 325 } 326 memcpy(node->actual_name, actual_name, namelen + 1); 327 } 328 node->namelen = namelen; 329 node->nid = ptr_to_id(node); 330 node->gen = fuse->next_generation++; 331 acquire_node_locked(node); 332 add_node_to_parent_locked(node, parent); 333 return node; 334} 335 336static int rename_node_locked(struct node *node, const char *name, 337 const char* actual_name) 338{ 339 size_t namelen = strlen(name); 340 int need_actual_name = strcmp(name, actual_name); 341 342 /* make the storage bigger without actually changing the name 343 * in case an error occurs part way */ 344 if (namelen > node->namelen) { 345 char* new_name = realloc(node->name, namelen + 1); 346 if (!new_name) { 347 return -ENOMEM; 348 } 349 node->name = new_name; 350 if (need_actual_name && node->actual_name) { 351 char* new_actual_name = realloc(node->actual_name, namelen + 1); 352 if (!new_actual_name) { 353 return -ENOMEM; 354 } 355 node->actual_name = new_actual_name; 356 } 357 } 358 359 /* update the name, taking care to allocate storage before overwriting the old name */ 360 if (need_actual_name) { 361 if (!node->actual_name) { 362 node->actual_name = malloc(namelen + 1); 363 if (!node->actual_name) { 364 return -ENOMEM; 365 } 366 } 367 memcpy(node->actual_name, actual_name, namelen + 1); 368 } else { 369 free(node->actual_name); 370 node->actual_name = NULL; 371 } 372 memcpy(node->name, name, namelen + 1); 373 node->namelen = namelen; 374 return 0; 375} 376 377static struct node *lookup_node_by_id_locked(struct fuse *fuse, __u64 nid) 378{ 379 if (nid == FUSE_ROOT_ID) { 380 return &fuse->root; 381 } else { 382 return id_to_ptr(nid); 383 } 384} 385 386static struct node* lookup_node_and_path_by_id_locked(struct fuse* fuse, __u64 nid, 387 char* buf, size_t bufsize) 388{ 389 struct node* node = lookup_node_by_id_locked(fuse, nid); 390 if (node && get_node_path_locked(node, buf, bufsize) < 0) { 391 node = NULL; 392 } 393 return node; 394} 395 396static struct node *lookup_child_by_name_locked(struct node *node, const char *name) 397{ 398 for (node = node->child; node; node = node->next) { 399 /* use exact string comparison, nodes that differ by case 400 * must be considered distinct even if they refer to the same 401 * underlying file as otherwise operations such as "mv x x" 402 * will not work because the source and target nodes are the same. */ 403 if (!strcmp(name, node->name)) { 404 return node; 405 } 406 } 407 return 0; 408} 409 410static struct node* acquire_or_create_child_locked( 411 struct fuse* fuse, struct node* parent, 412 const char* name, const char* actual_name) 413{ 414 struct node* child = lookup_child_by_name_locked(parent, name); 415 if (child) { 416 acquire_node_locked(child); 417 } else { 418 child = create_node_locked(fuse, parent, name, actual_name); 419 } 420 return child; 421} 422 423static void fuse_init(struct fuse *fuse, int fd, const char *source_path) 424{ 425 pthread_mutex_init(&fuse->lock, NULL); 426 427 fuse->fd = fd; 428 fuse->next_generation = 0; 429 430 memset(&fuse->root, 0, sizeof(fuse->root)); 431 fuse->root.nid = FUSE_ROOT_ID; /* 1 */ 432 fuse->root.refcount = 2; 433 fuse->root.namelen = strlen(source_path); 434 fuse->root.name = strdup(source_path); 435} 436 437static void fuse_status(struct fuse *fuse, __u64 unique, int err) 438{ 439 struct fuse_out_header hdr; 440 hdr.len = sizeof(hdr); 441 hdr.error = err; 442 hdr.unique = unique; 443 write(fuse->fd, &hdr, sizeof(hdr)); 444} 445 446static void fuse_reply(struct fuse *fuse, __u64 unique, void *data, int len) 447{ 448 struct fuse_out_header hdr; 449 struct iovec vec[2]; 450 int res; 451 452 hdr.len = len + sizeof(hdr); 453 hdr.error = 0; 454 hdr.unique = unique; 455 456 vec[0].iov_base = &hdr; 457 vec[0].iov_len = sizeof(hdr); 458 vec[1].iov_base = data; 459 vec[1].iov_len = len; 460 461 res = writev(fuse->fd, vec, 2); 462 if (res < 0) { 463 ERROR("*** REPLY FAILED *** %d\n", errno); 464 } 465} 466 467static int fuse_reply_entry(struct fuse* fuse, __u64 unique, 468 struct node* parent, const char* name, const char* actual_name, 469 const char* path) 470{ 471 struct node* node; 472 struct fuse_entry_out out; 473 struct stat s; 474 475 if (lstat(path, &s) < 0) { 476 return -errno; 477 } 478 479 pthread_mutex_lock(&fuse->lock); 480 node = acquire_or_create_child_locked(fuse, parent, name, actual_name); 481 if (!node) { 482 pthread_mutex_unlock(&fuse->lock); 483 return -ENOMEM; 484 } 485 memset(&out, 0, sizeof(out)); 486 attr_from_stat(&out.attr, &s, node->nid); 487 out.attr_valid = 10; 488 out.entry_valid = 10; 489 out.nodeid = node->nid; 490 out.generation = node->gen; 491 pthread_mutex_unlock(&fuse->lock); 492 fuse_reply(fuse, unique, &out, sizeof(out)); 493 return NO_STATUS; 494} 495 496static int fuse_reply_attr(struct fuse* fuse, __u64 unique, __u64 nid, 497 const char* path) 498{ 499 struct fuse_attr_out out; 500 struct stat s; 501 502 if (lstat(path, &s) < 0) { 503 return -errno; 504 } 505 memset(&out, 0, sizeof(out)); 506 attr_from_stat(&out.attr, &s, nid); 507 out.attr_valid = 10; 508 fuse_reply(fuse, unique, &out, sizeof(out)); 509 return NO_STATUS; 510} 511 512static int handle_lookup(struct fuse* fuse, struct fuse_handler* handler, 513 const struct fuse_in_header *hdr, const char* name) 514{ 515 struct node* parent_node; 516 char parent_path[PATH_MAX]; 517 char child_path[PATH_MAX]; 518 const char* actual_name; 519 520 pthread_mutex_lock(&fuse->lock); 521 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 522 parent_path, sizeof(parent_path)); 523 TRACE("[%d] LOOKUP %s @ %llx (%s)\n", handler->token, name, hdr->nodeid, 524 parent_node ? parent_node->name : "?"); 525 pthread_mutex_unlock(&fuse->lock); 526 527 if (!parent_node || !(actual_name = find_file_within(parent_path, name, 528 child_path, sizeof(child_path), 1))) { 529 return -ENOENT; 530 } 531 return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path); 532} 533 534static int handle_forget(struct fuse* fuse, struct fuse_handler* handler, 535 const struct fuse_in_header *hdr, const struct fuse_forget_in *req) 536{ 537 struct node* node; 538 539 pthread_mutex_lock(&fuse->lock); 540 node = lookup_node_by_id_locked(fuse, hdr->nodeid); 541 TRACE("[%d] FORGET #%lld @ %llx (%s)\n", handler->token, req->nlookup, 542 hdr->nodeid, node ? node->name : "?"); 543 if (node) { 544 __u64 n = req->nlookup; 545 while (n--) { 546 release_node_locked(node); 547 } 548 } 549 pthread_mutex_unlock(&fuse->lock); 550 return NO_STATUS; /* no reply */ 551} 552 553static int handle_getattr(struct fuse* fuse, struct fuse_handler* handler, 554 const struct fuse_in_header *hdr, const struct fuse_getattr_in *req) 555{ 556 struct node* node; 557 char path[PATH_MAX]; 558 559 pthread_mutex_lock(&fuse->lock); 560 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 561 TRACE("[%d] GETATTR flags=%x fh=%llx @ %llx (%s)\n", handler->token, 562 req->getattr_flags, req->fh, hdr->nodeid, node ? node->name : "?"); 563 pthread_mutex_unlock(&fuse->lock); 564 565 if (!node) { 566 return -ENOENT; 567 } 568 return fuse_reply_attr(fuse, hdr->unique, hdr->nodeid, path); 569} 570 571static int handle_setattr(struct fuse* fuse, struct fuse_handler* handler, 572 const struct fuse_in_header *hdr, const struct fuse_setattr_in *req) 573{ 574 struct node* node; 575 char path[PATH_MAX]; 576 struct timespec times[2]; 577 578 pthread_mutex_lock(&fuse->lock); 579 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 580 TRACE("[%d] SETATTR fh=%llx valid=%x @ %llx (%s)\n", handler->token, 581 req->fh, req->valid, hdr->nodeid, node ? node->name : "?"); 582 pthread_mutex_unlock(&fuse->lock); 583 584 if (!node) { 585 return -ENOENT; 586 } 587 588 /* XXX: incomplete implementation on purpose. 589 * chmod/chown should NEVER be implemented.*/ 590 591 if ((req->valid & FATTR_SIZE) && truncate(path, req->size) < 0) { 592 return -errno; 593 } 594 595 /* Handle changing atime and mtime. If FATTR_ATIME_and FATTR_ATIME_NOW 596 * are both set, then set it to the current time. Else, set it to the 597 * time specified in the request. Same goes for mtime. Use utimensat(2) 598 * as it allows ATIME and MTIME to be changed independently, and has 599 * nanosecond resolution which fuse also has. 600 */ 601 if (req->valid & (FATTR_ATIME | FATTR_MTIME)) { 602 times[0].tv_nsec = UTIME_OMIT; 603 times[1].tv_nsec = UTIME_OMIT; 604 if (req->valid & FATTR_ATIME) { 605 if (req->valid & FATTR_ATIME_NOW) { 606 times[0].tv_nsec = UTIME_NOW; 607 } else { 608 times[0].tv_sec = req->atime; 609 times[0].tv_nsec = req->atimensec; 610 } 611 } 612 if (req->valid & FATTR_MTIME) { 613 if (req->valid & FATTR_MTIME_NOW) { 614 times[1].tv_nsec = UTIME_NOW; 615 } else { 616 times[1].tv_sec = req->mtime; 617 times[1].tv_nsec = req->mtimensec; 618 } 619 } 620 TRACE("[%d] Calling utimensat on %s with atime %ld, mtime=%ld\n", 621 handler->token, path, times[0].tv_sec, times[1].tv_sec); 622 if (utimensat(-1, path, times, 0) < 0) { 623 return -errno; 624 } 625 } 626 return fuse_reply_attr(fuse, hdr->unique, hdr->nodeid, path); 627} 628 629static int handle_mknod(struct fuse* fuse, struct fuse_handler* handler, 630 const struct fuse_in_header* hdr, const struct fuse_mknod_in* req, const char* name) 631{ 632 struct node* parent_node; 633 char parent_path[PATH_MAX]; 634 char child_path[PATH_MAX]; 635 const char* actual_name; 636 637 pthread_mutex_lock(&fuse->lock); 638 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 639 parent_path, sizeof(parent_path)); 640 TRACE("[%d] MKNOD %s 0%o @ %llx (%s)\n", handler->token, 641 name, req->mode, hdr->nodeid, parent_node ? parent_node->name : "?"); 642 pthread_mutex_unlock(&fuse->lock); 643 644 if (!parent_node || !(actual_name = find_file_within(parent_path, name, 645 child_path, sizeof(child_path), 1))) { 646 return -ENOENT; 647 } 648 __u32 mode = (req->mode & (~0777)) | 0664; 649 if (mknod(child_path, mode, req->rdev) < 0) { 650 return -errno; 651 } 652 return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path); 653} 654 655static int handle_mkdir(struct fuse* fuse, struct fuse_handler* handler, 656 const struct fuse_in_header* hdr, const struct fuse_mkdir_in* req, const char* name) 657{ 658 struct node* parent_node; 659 char parent_path[PATH_MAX]; 660 char child_path[PATH_MAX]; 661 const char* actual_name; 662 663 pthread_mutex_lock(&fuse->lock); 664 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 665 parent_path, sizeof(parent_path)); 666 TRACE("[%d] MKDIR %s 0%o @ %llx (%s)\n", handler->token, 667 name, req->mode, hdr->nodeid, parent_node ? parent_node->name : "?"); 668 pthread_mutex_unlock(&fuse->lock); 669 670 if (!parent_node || !(actual_name = find_file_within(parent_path, name, 671 child_path, sizeof(child_path), 1))) { 672 return -ENOENT; 673 } 674 __u32 mode = (req->mode & (~0777)) | 0775; 675 if (mkdir(child_path, mode) < 0) { 676 return -errno; 677 } 678 return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path); 679} 680 681static int handle_unlink(struct fuse* fuse, struct fuse_handler* handler, 682 const struct fuse_in_header* hdr, const char* name) 683{ 684 struct node* parent_node; 685 char parent_path[PATH_MAX]; 686 char child_path[PATH_MAX]; 687 688 pthread_mutex_lock(&fuse->lock); 689 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 690 parent_path, sizeof(parent_path)); 691 TRACE("[%d] UNLINK %s @ %llx (%s)\n", handler->token, 692 name, hdr->nodeid, parent_node ? parent_node->name : "?"); 693 pthread_mutex_unlock(&fuse->lock); 694 695 if (!parent_node || !find_file_within(parent_path, name, 696 child_path, sizeof(child_path), 1)) { 697 return -ENOENT; 698 } 699 if (unlink(child_path) < 0) { 700 return -errno; 701 } 702 return 0; 703} 704 705static int handle_rmdir(struct fuse* fuse, struct fuse_handler* handler, 706 const struct fuse_in_header* hdr, const char* name) 707{ 708 struct node* parent_node; 709 char parent_path[PATH_MAX]; 710 char child_path[PATH_MAX]; 711 712 pthread_mutex_lock(&fuse->lock); 713 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 714 parent_path, sizeof(parent_path)); 715 TRACE("[%d] RMDIR %s @ %llx (%s)\n", handler->token, 716 name, hdr->nodeid, parent_node ? parent_node->name : "?"); 717 pthread_mutex_unlock(&fuse->lock); 718 719 if (!parent_node || !find_file_within(parent_path, name, 720 child_path, sizeof(child_path), 1)) { 721 return -ENOENT; 722 } 723 if (rmdir(child_path) < 0) { 724 return -errno; 725 } 726 return 0; 727} 728 729static int handle_rename(struct fuse* fuse, struct fuse_handler* handler, 730 const struct fuse_in_header* hdr, const struct fuse_rename_in* req, 731 const char* old_name, const char* new_name) 732{ 733 struct node* old_parent_node; 734 struct node* new_parent_node; 735 struct node* child_node; 736 char old_parent_path[PATH_MAX]; 737 char new_parent_path[PATH_MAX]; 738 char old_child_path[PATH_MAX]; 739 char new_child_path[PATH_MAX]; 740 const char* new_actual_name; 741 int res; 742 743 pthread_mutex_lock(&fuse->lock); 744 old_parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 745 old_parent_path, sizeof(old_parent_path)); 746 new_parent_node = lookup_node_and_path_by_id_locked(fuse, req->newdir, 747 new_parent_path, sizeof(new_parent_path)); 748 TRACE("[%d] RENAME %s->%s @ %llx (%s) -> %llx (%s)\n", handler->token, 749 old_name, new_name, 750 hdr->nodeid, old_parent_node ? old_parent_node->name : "?", 751 req->newdir, new_parent_node ? new_parent_node->name : "?"); 752 if (!old_parent_node || !new_parent_node) { 753 res = -ENOENT; 754 goto lookup_error; 755 } 756 child_node = lookup_child_by_name_locked(old_parent_node, old_name); 757 if (!child_node || get_node_path_locked(child_node, 758 old_child_path, sizeof(old_child_path)) < 0) { 759 res = -ENOENT; 760 goto lookup_error; 761 } 762 acquire_node_locked(child_node); 763 pthread_mutex_unlock(&fuse->lock); 764 765 /* Special case for renaming a file where destination is same path 766 * differing only by case. In this case we don't want to look for a case 767 * insensitive match. This allows commands like "mv foo FOO" to work as expected. 768 */ 769 int search = old_parent_node != new_parent_node 770 || strcasecmp(old_name, new_name); 771 if (!(new_actual_name = find_file_within(new_parent_path, new_name, 772 new_child_path, sizeof(new_child_path), search))) { 773 res = -ENOENT; 774 goto io_error; 775 } 776 777 TRACE("[%d] RENAME %s->%s\n", handler->token, old_child_path, new_child_path); 778 res = rename(old_child_path, new_child_path); 779 if (res < 0) { 780 res = -errno; 781 goto io_error; 782 } 783 784 pthread_mutex_lock(&fuse->lock); 785 res = rename_node_locked(child_node, new_name, new_actual_name); 786 if (!res) { 787 remove_node_from_parent_locked(child_node); 788 add_node_to_parent_locked(child_node, new_parent_node); 789 } 790 goto done; 791 792io_error: 793 pthread_mutex_lock(&fuse->lock); 794done: 795 release_node_locked(child_node); 796lookup_error: 797 pthread_mutex_unlock(&fuse->lock); 798 return res; 799} 800 801static int handle_open(struct fuse* fuse, struct fuse_handler* handler, 802 const struct fuse_in_header* hdr, const struct fuse_open_in* req) 803{ 804 struct node* node; 805 char path[PATH_MAX]; 806 struct fuse_open_out out; 807 struct handle *h; 808 809 pthread_mutex_lock(&fuse->lock); 810 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 811 TRACE("[%d] OPEN 0%o @ %llx (%s)\n", handler->token, 812 req->flags, hdr->nodeid, node ? node->name : "?"); 813 pthread_mutex_unlock(&fuse->lock); 814 815 if (!node) { 816 return -ENOENT; 817 } 818 h = malloc(sizeof(*h)); 819 if (!h) { 820 return -ENOMEM; 821 } 822 TRACE("[%d] OPEN %s\n", handler->token, path); 823 h->fd = open(path, req->flags); 824 if (h->fd < 0) { 825 free(h); 826 return -errno; 827 } 828 out.fh = ptr_to_id(h); 829 out.open_flags = 0; 830 out.padding = 0; 831 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 832 return NO_STATUS; 833} 834 835static int handle_read(struct fuse* fuse, struct fuse_handler* handler, 836 const struct fuse_in_header* hdr, const struct fuse_read_in* req) 837{ 838 struct handle *h = id_to_ptr(req->fh); 839 __u64 unique = hdr->unique; 840 __u32 size = req->size; 841 __u64 offset = req->offset; 842 int res; 843 844 /* Don't access any other fields of hdr or req beyond this point, the read buffer 845 * overlaps the request buffer and will clobber data in the request. This 846 * saves us 128KB per request handler thread at the cost of this scary comment. */ 847 848 TRACE("[%d] READ %p(%d) %u@%llu\n", handler->token, 849 h, h->fd, size, offset); 850 if (size > sizeof(handler->read_buffer)) { 851 return -EINVAL; 852 } 853 res = pread64(h->fd, handler->read_buffer, size, offset); 854 if (res < 0) { 855 return -errno; 856 } 857 fuse_reply(fuse, unique, handler->read_buffer, res); 858 return NO_STATUS; 859} 860 861static int handle_write(struct fuse* fuse, struct fuse_handler* handler, 862 const struct fuse_in_header* hdr, const struct fuse_write_in* req, 863 const void* buffer) 864{ 865 struct fuse_write_out out; 866 struct handle *h = id_to_ptr(req->fh); 867 int res; 868 869 TRACE("[%d] WRITE %p(%d) %u@%llu\n", handler->token, 870 h, h->fd, req->size, req->offset); 871 res = pwrite64(h->fd, buffer, req->size, req->offset); 872 if (res < 0) { 873 return -errno; 874 } 875 out.size = res; 876 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 877 return NO_STATUS; 878} 879 880static int handle_statfs(struct fuse* fuse, struct fuse_handler* handler, 881 const struct fuse_in_header* hdr) 882{ 883 char path[PATH_MAX]; 884 struct statfs stat; 885 struct fuse_statfs_out out; 886 int res; 887 888 pthread_mutex_lock(&fuse->lock); 889 TRACE("[%d] STATFS\n", handler->token); 890 res = get_node_path_locked(&fuse->root, path, sizeof(path)); 891 pthread_mutex_unlock(&fuse->lock); 892 if (res < 0) { 893 return -ENOENT; 894 } 895 if (statfs(fuse->root.name, &stat) < 0) { 896 return -errno; 897 } 898 memset(&out, 0, sizeof(out)); 899 out.st.blocks = stat.f_blocks; 900 out.st.bfree = stat.f_bfree; 901 out.st.bavail = stat.f_bavail; 902 out.st.files = stat.f_files; 903 out.st.ffree = stat.f_ffree; 904 out.st.bsize = stat.f_bsize; 905 out.st.namelen = stat.f_namelen; 906 out.st.frsize = stat.f_frsize; 907 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 908 return NO_STATUS; 909} 910 911static int handle_release(struct fuse* fuse, struct fuse_handler* handler, 912 const struct fuse_in_header* hdr, const struct fuse_release_in* req) 913{ 914 struct handle *h = id_to_ptr(req->fh); 915 916 TRACE("[%d] RELEASE %p(%d)\n", handler->token, h, h->fd); 917 close(h->fd); 918 free(h); 919 return 0; 920} 921 922static int handle_fsync(struct fuse* fuse, struct fuse_handler* handler, 923 const struct fuse_in_header* hdr, const struct fuse_fsync_in* req) 924{ 925 int is_data_sync = req->fsync_flags & 1; 926 struct handle *h = id_to_ptr(req->fh); 927 int res; 928 929 TRACE("[%d] FSYNC %p(%d) is_data_sync=%d\n", handler->token, 930 h, h->fd, is_data_sync); 931 res = is_data_sync ? fdatasync(h->fd) : fsync(h->fd); 932 if (res < 0) { 933 return -errno; 934 } 935 return 0; 936} 937 938static int handle_flush(struct fuse* fuse, struct fuse_handler* handler, 939 const struct fuse_in_header* hdr) 940{ 941 TRACE("[%d] FLUSH\n", handler->token); 942 return 0; 943} 944 945static int handle_opendir(struct fuse* fuse, struct fuse_handler* handler, 946 const struct fuse_in_header* hdr, const struct fuse_open_in* req) 947{ 948 struct node* node; 949 char path[PATH_MAX]; 950 struct fuse_open_out out; 951 struct dirhandle *h; 952 953 pthread_mutex_lock(&fuse->lock); 954 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 955 TRACE("[%d] OPENDIR @ %llx (%s)\n", handler->token, 956 hdr->nodeid, node ? node->name : "?"); 957 pthread_mutex_unlock(&fuse->lock); 958 959 if (!node) { 960 return -ENOENT; 961 } 962 h = malloc(sizeof(*h)); 963 if (!h) { 964 return -ENOMEM; 965 } 966 TRACE("[%d] OPENDIR %s\n", handler->token, path); 967 h->d = opendir(path); 968 if (!h->d) { 969 free(h); 970 return -errno; 971 } 972 out.fh = ptr_to_id(h); 973 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 974 return NO_STATUS; 975} 976 977static int handle_readdir(struct fuse* fuse, struct fuse_handler* handler, 978 const struct fuse_in_header* hdr, const struct fuse_read_in* req) 979{ 980 char buffer[8192]; 981 struct fuse_dirent *fde = (struct fuse_dirent*) buffer; 982 struct dirent *de; 983 struct dirhandle *h = id_to_ptr(req->fh); 984 985 TRACE("[%d] READDIR %p\n", handler->token, h); 986 if (req->offset == 0) { 987 /* rewinddir() might have been called above us, so rewind here too */ 988 TRACE("[%d] calling rewinddir()\n", handler->token); 989 rewinddir(h->d); 990 } 991 de = readdir(h->d); 992 if (!de) { 993 return 0; 994 } 995 fde->ino = FUSE_UNKNOWN_INO; 996 /* increment the offset so we can detect when rewinddir() seeks back to the beginning */ 997 fde->off = req->offset + 1; 998 fde->type = de->d_type; 999 fde->namelen = strlen(de->d_name); 1000 memcpy(fde->name, de->d_name, fde->namelen + 1); 1001 fuse_reply(fuse, hdr->unique, fde, 1002 FUSE_DIRENT_ALIGN(sizeof(struct fuse_dirent) + fde->namelen)); 1003 return NO_STATUS; 1004} 1005 1006static int handle_releasedir(struct fuse* fuse, struct fuse_handler* handler, 1007 const struct fuse_in_header* hdr, const struct fuse_release_in* req) 1008{ 1009 struct dirhandle *h = id_to_ptr(req->fh); 1010 1011 TRACE("[%d] RELEASEDIR %p\n", handler->token, h); 1012 closedir(h->d); 1013 free(h); 1014 return 0; 1015} 1016 1017static int handle_init(struct fuse* fuse, struct fuse_handler* handler, 1018 const struct fuse_in_header* hdr, const struct fuse_init_in* req) 1019{ 1020 struct fuse_init_out out; 1021 1022 TRACE("[%d] INIT ver=%d.%d maxread=%d flags=%x\n", 1023 handler->token, req->major, req->minor, req->max_readahead, req->flags); 1024 out.major = FUSE_KERNEL_VERSION; 1025 out.minor = FUSE_KERNEL_MINOR_VERSION; 1026 out.max_readahead = req->max_readahead; 1027 out.flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES; 1028 out.max_background = 32; 1029 out.congestion_threshold = 32; 1030 out.max_write = MAX_WRITE; 1031 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 1032 return NO_STATUS; 1033} 1034 1035static int handle_fuse_request(struct fuse *fuse, struct fuse_handler* handler, 1036 const struct fuse_in_header *hdr, const void *data, size_t data_len) 1037{ 1038 switch (hdr->opcode) { 1039 case FUSE_LOOKUP: { /* bytez[] -> entry_out */ 1040 const char* name = data; 1041 return handle_lookup(fuse, handler, hdr, name); 1042 } 1043 1044 case FUSE_FORGET: { 1045 const struct fuse_forget_in *req = data; 1046 return handle_forget(fuse, handler, hdr, req); 1047 } 1048 1049 case FUSE_GETATTR: { /* getattr_in -> attr_out */ 1050 const struct fuse_getattr_in *req = data; 1051 return handle_getattr(fuse, handler, hdr, req); 1052 } 1053 1054 case FUSE_SETATTR: { /* setattr_in -> attr_out */ 1055 const struct fuse_setattr_in *req = data; 1056 return handle_setattr(fuse, handler, hdr, req); 1057 } 1058 1059// case FUSE_READLINK: 1060// case FUSE_SYMLINK: 1061 case FUSE_MKNOD: { /* mknod_in, bytez[] -> entry_out */ 1062 const struct fuse_mknod_in *req = data; 1063 const char *name = ((const char*) data) + sizeof(*req); 1064 return handle_mknod(fuse, handler, hdr, req, name); 1065 } 1066 1067 case FUSE_MKDIR: { /* mkdir_in, bytez[] -> entry_out */ 1068 const struct fuse_mkdir_in *req = data; 1069 const char *name = ((const char*) data) + sizeof(*req); 1070 return handle_mkdir(fuse, handler, hdr, req, name); 1071 } 1072 1073 case FUSE_UNLINK: { /* bytez[] -> */ 1074 const char* name = data; 1075 return handle_unlink(fuse, handler, hdr, name); 1076 } 1077 1078 case FUSE_RMDIR: { /* bytez[] -> */ 1079 const char* name = data; 1080 return handle_rmdir(fuse, handler, hdr, name); 1081 } 1082 1083 case FUSE_RENAME: { /* rename_in, oldname, newname -> */ 1084 const struct fuse_rename_in *req = data; 1085 const char *old_name = ((const char*) data) + sizeof(*req); 1086 const char *new_name = old_name + strlen(old_name) + 1; 1087 return handle_rename(fuse, handler, hdr, req, old_name, new_name); 1088 } 1089 1090// case FUSE_LINK: 1091 case FUSE_OPEN: { /* open_in -> open_out */ 1092 const struct fuse_open_in *req = data; 1093 return handle_open(fuse, handler, hdr, req); 1094 } 1095 1096 case FUSE_READ: { /* read_in -> byte[] */ 1097 const struct fuse_read_in *req = data; 1098 return handle_read(fuse, handler, hdr, req); 1099 } 1100 1101 case FUSE_WRITE: { /* write_in, byte[write_in.size] -> write_out */ 1102 const struct fuse_write_in *req = data; 1103 const void* buffer = (const __u8*)data + sizeof(*req); 1104 return handle_write(fuse, handler, hdr, req, buffer); 1105 } 1106 1107 case FUSE_STATFS: { /* getattr_in -> attr_out */ 1108 return handle_statfs(fuse, handler, hdr); 1109 } 1110 1111 case FUSE_RELEASE: { /* release_in -> */ 1112 const struct fuse_release_in *req = data; 1113 return handle_release(fuse, handler, hdr, req); 1114 } 1115 1116 case FUSE_FSYNC: { 1117 const struct fuse_fsync_in *req = data; 1118 return handle_fsync(fuse, handler, hdr, req); 1119 } 1120 1121// case FUSE_SETXATTR: 1122// case FUSE_GETXATTR: 1123// case FUSE_LISTXATTR: 1124// case FUSE_REMOVEXATTR: 1125 case FUSE_FLUSH: { 1126 return handle_flush(fuse, handler, hdr); 1127 } 1128 1129 case FUSE_OPENDIR: { /* open_in -> open_out */ 1130 const struct fuse_open_in *req = data; 1131 return handle_opendir(fuse, handler, hdr, req); 1132 } 1133 1134 case FUSE_READDIR: { 1135 const struct fuse_read_in *req = data; 1136 return handle_readdir(fuse, handler, hdr, req); 1137 } 1138 1139 case FUSE_RELEASEDIR: { /* release_in -> */ 1140 const struct fuse_release_in *req = data; 1141 return handle_releasedir(fuse, handler, hdr, req); 1142 } 1143 1144// case FUSE_FSYNCDIR: 1145 case FUSE_INIT: { /* init_in -> init_out */ 1146 const struct fuse_init_in *req = data; 1147 return handle_init(fuse, handler, hdr, req); 1148 } 1149 1150 default: { 1151 TRACE("[%d] NOTIMPL op=%d uniq=%llx nid=%llx\n", 1152 handler->token, hdr->opcode, hdr->unique, hdr->nodeid); 1153 return -ENOSYS; 1154 } 1155 } 1156} 1157 1158static void handle_fuse_requests(struct fuse_handler* handler) 1159{ 1160 struct fuse* fuse = handler->fuse; 1161 for (;;) { 1162 ssize_t len = read(fuse->fd, 1163 handler->request_buffer, sizeof(handler->request_buffer)); 1164 if (len < 0) { 1165 if (errno != EINTR) { 1166 ERROR("[%d] handle_fuse_requests: errno=%d\n", handler->token, errno); 1167 } 1168 continue; 1169 } 1170 1171 if ((size_t)len < sizeof(struct fuse_in_header)) { 1172 ERROR("[%d] request too short: len=%zu\n", handler->token, (size_t)len); 1173 continue; 1174 } 1175 1176 const struct fuse_in_header *hdr = (void*)handler->request_buffer; 1177 if (hdr->len != (size_t)len) { 1178 ERROR("[%d] malformed header: len=%zu, hdr->len=%u\n", 1179 handler->token, (size_t)len, hdr->len); 1180 continue; 1181 } 1182 1183 const void *data = handler->request_buffer + sizeof(struct fuse_in_header); 1184 size_t data_len = len - sizeof(struct fuse_in_header); 1185 __u64 unique = hdr->unique; 1186 int res = handle_fuse_request(fuse, handler, hdr, data, data_len); 1187 1188 /* We do not access the request again after this point because the underlying 1189 * buffer storage may have been reused while processing the request. */ 1190 1191 if (res != NO_STATUS) { 1192 if (res) { 1193 TRACE("[%d] ERROR %d\n", handler->token, res); 1194 } 1195 fuse_status(fuse, unique, res); 1196 } 1197 } 1198} 1199 1200static void* start_handler(void* data) 1201{ 1202 struct fuse_handler* handler = data; 1203 handle_fuse_requests(handler); 1204 return NULL; 1205} 1206 1207static int ignite_fuse(struct fuse* fuse, int num_threads) 1208{ 1209 struct fuse_handler* handlers; 1210 int i; 1211 1212 handlers = malloc(num_threads * sizeof(struct fuse_handler)); 1213 if (!handlers) { 1214 ERROR("cannot allocate storage for threads"); 1215 return -ENOMEM; 1216 } 1217 1218 for (i = 0; i < num_threads; i++) { 1219 handlers[i].fuse = fuse; 1220 handlers[i].token = i; 1221 } 1222 1223 for (i = 1; i < num_threads; i++) { 1224 pthread_t thread; 1225 int res = pthread_create(&thread, NULL, start_handler, &handlers[i]); 1226 if (res) { 1227 ERROR("failed to start thread #%d, error=%d", i, res); 1228 goto quit; 1229 } 1230 } 1231 handle_fuse_requests(&handlers[0]); 1232 ERROR("terminated prematurely"); 1233 1234 /* don't bother killing all of the other threads or freeing anything, 1235 * should never get here anyhow */ 1236quit: 1237 exit(1); 1238} 1239 1240static int usage() 1241{ 1242 ERROR("usage: sdcard [-t<threads>] <source_path> <dest_path> <uid> <gid>\n" 1243 " -t<threads>: specify number of threads to use, default -t%d\n" 1244 "\n", DEFAULT_NUM_THREADS); 1245 return 1; 1246} 1247 1248static int run(const char* source_path, const char* dest_path, uid_t uid, gid_t gid, 1249 int num_threads) { 1250 int fd; 1251 char opts[256]; 1252 int res; 1253 struct fuse fuse; 1254 1255 /* cleanup from previous instance, if necessary */ 1256 umount2(dest_path, 2); 1257 1258 fd = open("/dev/fuse", O_RDWR); 1259 if (fd < 0){ 1260 ERROR("cannot open fuse device (error %d)\n", errno); 1261 return -1; 1262 } 1263 1264 snprintf(opts, sizeof(opts), 1265 "fd=%i,rootmode=40000,default_permissions,allow_other,user_id=%d,group_id=%d", 1266 fd, uid, gid); 1267 1268 res = mount("/dev/fuse", dest_path, "fuse", MS_NOSUID | MS_NODEV, opts); 1269 if (res < 0) { 1270 ERROR("cannot mount fuse filesystem (error %d)\n", errno); 1271 goto error; 1272 } 1273 1274 res = setgid(gid); 1275 if (res < 0) { 1276 ERROR("cannot setgid (error %d)\n", errno); 1277 goto error; 1278 } 1279 1280 res = setuid(uid); 1281 if (res < 0) { 1282 ERROR("cannot setuid (error %d)\n", errno); 1283 goto error; 1284 } 1285 1286 fuse_init(&fuse, fd, source_path); 1287 1288 umask(0); 1289 res = ignite_fuse(&fuse, num_threads); 1290 1291 /* we do not attempt to umount the file system here because we are no longer 1292 * running as the root user */ 1293 1294error: 1295 close(fd); 1296 return res; 1297} 1298 1299int main(int argc, char **argv) 1300{ 1301 int res; 1302 const char *source_path = NULL; 1303 const char *dest_path = NULL; 1304 uid_t uid = 0; 1305 gid_t gid = 0; 1306 int num_threads = DEFAULT_NUM_THREADS; 1307 int i; 1308 1309 for (i = 1; i < argc; i++) { 1310 char* arg = argv[i]; 1311 if (!strncmp(arg, "-t", 2)) 1312 num_threads = strtoul(arg + 2, 0, 10); 1313 else if (!source_path) 1314 source_path = arg; 1315 else if (!dest_path) 1316 dest_path = arg; 1317 else if (!uid) { 1318 char* endptr = NULL; 1319 errno = 0; 1320 uid = strtoul(arg, &endptr, 10); 1321 if (*endptr != '\0' || errno != 0) { 1322 ERROR("Invalid uid"); 1323 return usage(); 1324 } 1325 } else if (!gid) { 1326 char* endptr = NULL; 1327 errno = 0; 1328 gid = strtoul(arg, &endptr, 10); 1329 if (*endptr != '\0' || errno != 0) { 1330 ERROR("Invalid gid"); 1331 return usage(); 1332 } 1333 } else { 1334 ERROR("too many arguments\n"); 1335 return usage(); 1336 } 1337 } 1338 1339 if (!source_path) { 1340 ERROR("no source path specified\n"); 1341 return usage(); 1342 } 1343 if (!dest_path) { 1344 ERROR("no dest path specified\n"); 1345 return usage(); 1346 } 1347 if (!uid || !gid) { 1348 ERROR("uid and gid must be nonzero\n"); 1349 return usage(); 1350 } 1351 if (num_threads < 1) { 1352 ERROR("number of threads must be at least 1\n"); 1353 return usage(); 1354 } 1355 1356 res = run(source_path, dest_path, uid, gid, num_threads); 1357 return res < 0 ? 1 : 0; 1358} 1359