sdcard.c revision 2fd72cc22171cc23e67206db795fc5025d4f7ac6
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#include <sys/time.h> 32#include <sys/resource.h> 33 34#include <private/android_filesystem_config.h> 35 36#include "fuse.h" 37 38/* README 39 * 40 * What is this? 41 * 42 * sdcard is a program that uses FUSE to emulate FAT-on-sdcard style 43 * directory permissions (all files are given fixed owner, group, and 44 * permissions at creation, owner, group, and permissions are not 45 * changeable, symlinks and hardlinks are not createable, etc. 46 * 47 * See usage() for command line options. 48 * 49 * It must be run as root, but will drop to requested UID/GID as soon as it 50 * mounts a filesystem. It will refuse to run if requested UID/GID are zero. 51 * 52 * Things I believe to be true: 53 * 54 * - ops that return a fuse_entry (LOOKUP, MKNOD, MKDIR, LINK, SYMLINK, 55 * CREAT) must bump that node's refcount 56 * - don't forget that FORGET can forget multiple references (req->nlookup) 57 * - if an op that returns a fuse_entry fails writing the reply to the 58 * kernel, you must rollback the refcount to reflect the reference the 59 * kernel did not actually acquire 60 */ 61 62#define FUSE_TRACE 0 63 64#if FUSE_TRACE 65#define TRACE(x...) fprintf(stderr,x) 66#else 67#define TRACE(x...) do {} while (0) 68#endif 69 70#define ERROR(x...) fprintf(stderr,x) 71 72#define FUSE_UNKNOWN_INO 0xffffffff 73 74/* Maximum number of bytes to write in one request. */ 75#define MAX_WRITE (256 * 1024) 76 77/* Maximum number of bytes to read in one request. */ 78#define MAX_READ (128 * 1024) 79 80/* Largest possible request. 81 * The request size is bounded by the maximum size of a FUSE_WRITE request because it has 82 * the largest possible data payload. */ 83#define MAX_REQUEST_SIZE (sizeof(struct fuse_in_header) + sizeof(struct fuse_write_in) + MAX_WRITE) 84 85/* Default number of threads. */ 86#define DEFAULT_NUM_THREADS 2 87 88/* Pseudo-error constant used to indicate that no fuse status is needed 89 * or that a reply has already been written. */ 90#define NO_STATUS 1 91 92struct handle { 93 int fd; 94}; 95 96struct dirhandle { 97 DIR *d; 98}; 99 100struct node { 101 __u32 refcount; 102 __u64 nid; 103 __u64 gen; 104 105 struct node *next; /* per-dir sibling list */ 106 struct node *child; /* first contained file by this dir */ 107 struct node *parent; /* containing directory */ 108 109 size_t namelen; 110 char *name; 111 /* If non-null, this is the real name of the file in the underlying storage. 112 * This may differ from the field "name" only by case. 113 * strlen(actual_name) will always equal strlen(name), so it is safe to use 114 * namelen for both fields. 115 */ 116 char *actual_name; 117}; 118 119/* Global data structure shared by all fuse handlers. */ 120struct fuse { 121 pthread_mutex_t lock; 122 123 __u64 next_generation; 124 int fd; 125 struct node root; 126 char rootpath[PATH_MAX]; 127}; 128 129/* Private data used by a single fuse handler. */ 130struct fuse_handler { 131 struct fuse* fuse; 132 int token; 133 134 /* To save memory, we never use the contents of the request buffer and the read 135 * buffer at the same time. This allows us to share the underlying storage. */ 136 union { 137 __u8 request_buffer[MAX_REQUEST_SIZE]; 138 __u8 read_buffer[MAX_READ]; 139 }; 140}; 141 142static inline void *id_to_ptr(__u64 nid) 143{ 144 return (void *) (uintptr_t) nid; 145} 146 147static inline __u64 ptr_to_id(void *ptr) 148{ 149 return (__u64) (uintptr_t) ptr; 150} 151 152static void acquire_node_locked(struct node* node) 153{ 154 node->refcount++; 155 TRACE("ACQUIRE %p (%s) rc=%d\n", node, node->name, node->refcount); 156} 157 158static void remove_node_from_parent_locked(struct node* node); 159 160static void release_node_locked(struct node* node) 161{ 162 TRACE("RELEASE %p (%s) rc=%d\n", node, node->name, node->refcount); 163 if (node->refcount > 0) { 164 node->refcount--; 165 if (!node->refcount) { 166 TRACE("DESTROY %p (%s)\n", node, node->name); 167 remove_node_from_parent_locked(node); 168 169 /* TODO: remove debugging - poison memory */ 170 memset(node->name, 0xef, node->namelen); 171 free(node->name); 172 free(node->actual_name); 173 memset(node, 0xfc, sizeof(*node)); 174 free(node); 175 } 176 } else { 177 ERROR("Zero refcnt %p\n", node); 178 } 179} 180 181static void add_node_to_parent_locked(struct node *node, struct node *parent) { 182 node->parent = parent; 183 node->next = parent->child; 184 parent->child = node; 185 acquire_node_locked(parent); 186} 187 188static void remove_node_from_parent_locked(struct node* node) 189{ 190 if (node->parent) { 191 if (node->parent->child == node) { 192 node->parent->child = node->parent->child->next; 193 } else { 194 struct node *node2; 195 node2 = node->parent->child; 196 while (node2->next != node) 197 node2 = node2->next; 198 node2->next = node->next; 199 } 200 release_node_locked(node->parent); 201 node->parent = NULL; 202 node->next = NULL; 203 } 204} 205 206/* Gets the absolute path to a node into the provided buffer. 207 * 208 * Populates 'buf' with the path and returns the length of the path on success, 209 * or returns -1 if the path is too long for the provided buffer. 210 */ 211static ssize_t get_node_path_locked(struct node* node, char* buf, size_t bufsize) 212{ 213 size_t namelen = node->namelen; 214 if (bufsize < namelen + 1) { 215 return -1; 216 } 217 218 ssize_t pathlen = 0; 219 if (node->parent) { 220 pathlen = get_node_path_locked(node->parent, buf, bufsize - namelen - 2); 221 if (pathlen < 0) { 222 return -1; 223 } 224 buf[pathlen++] = '/'; 225 } 226 227 const char* name = node->actual_name ? node->actual_name : node->name; 228 memcpy(buf + pathlen, name, namelen + 1); /* include trailing \0 */ 229 return pathlen + namelen; 230} 231 232/* Finds the absolute path of a file within a given directory. 233 * Performs a case-insensitive search for the file and sets the buffer to the path 234 * of the first matching file. If 'search' is zero or if no match is found, sets 235 * the buffer to the path that the file would have, assuming the name were case-sensitive. 236 * 237 * Populates 'buf' with the path and returns the actual name (within 'buf') on success, 238 * or returns NULL if the path is too long for the provided buffer. 239 */ 240static char* find_file_within(const char* path, const char* name, 241 char* buf, size_t bufsize, int search) 242{ 243 size_t pathlen = strlen(path); 244 size_t namelen = strlen(name); 245 size_t childlen = pathlen + namelen + 1; 246 char* actual; 247 248 if (bufsize <= childlen) { 249 return NULL; 250 } 251 252 memcpy(buf, path, pathlen); 253 buf[pathlen] = '/'; 254 actual = buf + pathlen + 1; 255 memcpy(actual, name, namelen + 1); 256 257 if (search && access(buf, F_OK)) { 258 struct dirent* entry; 259 DIR* dir = opendir(path); 260 if (!dir) { 261 ERROR("opendir %s failed: %s", path, strerror(errno)); 262 return actual; 263 } 264 while ((entry = readdir(dir))) { 265 if (!strcasecmp(entry->d_name, name)) { 266 /* we have a match - replace the name, don't need to copy the null again */ 267 memcpy(actual, entry->d_name, namelen); 268 break; 269 } 270 } 271 closedir(dir); 272 } 273 return actual; 274} 275 276static void attr_from_stat(struct fuse_attr *attr, const struct stat *s, __u64 nid) 277{ 278 attr->ino = nid; 279 attr->size = s->st_size; 280 attr->blocks = s->st_blocks; 281 attr->atime = s->st_atime; 282 attr->mtime = s->st_mtime; 283 attr->ctime = s->st_ctime; 284 attr->atimensec = s->st_atime_nsec; 285 attr->mtimensec = s->st_mtime_nsec; 286 attr->ctimensec = s->st_ctime_nsec; 287 attr->mode = s->st_mode; 288 attr->nlink = s->st_nlink; 289 290 /* force permissions to something reasonable: 291 * world readable 292 * writable by the sdcard group 293 */ 294 if (attr->mode & 0100) { 295 attr->mode = (attr->mode & (~0777)) | 0775; 296 } else { 297 attr->mode = (attr->mode & (~0777)) | 0664; 298 } 299 300 /* all files owned by root.sdcard */ 301 attr->uid = 0; 302 attr->gid = AID_SDCARD_RW; 303} 304 305struct node *create_node_locked(struct fuse* fuse, 306 struct node *parent, const char *name, const char* actual_name) 307{ 308 struct node *node; 309 size_t namelen = strlen(name); 310 311 node = calloc(1, sizeof(struct node)); 312 if (!node) { 313 return NULL; 314 } 315 node->name = malloc(namelen + 1); 316 if (!node->name) { 317 free(node); 318 return NULL; 319 } 320 memcpy(node->name, name, namelen + 1); 321 if (strcmp(name, actual_name)) { 322 node->actual_name = malloc(namelen + 1); 323 if (!node->actual_name) { 324 free(node->name); 325 free(node); 326 return NULL; 327 } 328 memcpy(node->actual_name, actual_name, namelen + 1); 329 } 330 node->namelen = namelen; 331 node->nid = ptr_to_id(node); 332 node->gen = fuse->next_generation++; 333 acquire_node_locked(node); 334 add_node_to_parent_locked(node, parent); 335 return node; 336} 337 338static int rename_node_locked(struct node *node, const char *name, 339 const char* actual_name) 340{ 341 size_t namelen = strlen(name); 342 int need_actual_name = strcmp(name, actual_name); 343 344 /* make the storage bigger without actually changing the name 345 * in case an error occurs part way */ 346 if (namelen > node->namelen) { 347 char* new_name = realloc(node->name, namelen + 1); 348 if (!new_name) { 349 return -ENOMEM; 350 } 351 node->name = new_name; 352 if (need_actual_name && node->actual_name) { 353 char* new_actual_name = realloc(node->actual_name, namelen + 1); 354 if (!new_actual_name) { 355 return -ENOMEM; 356 } 357 node->actual_name = new_actual_name; 358 } 359 } 360 361 /* update the name, taking care to allocate storage before overwriting the old name */ 362 if (need_actual_name) { 363 if (!node->actual_name) { 364 node->actual_name = malloc(namelen + 1); 365 if (!node->actual_name) { 366 return -ENOMEM; 367 } 368 } 369 memcpy(node->actual_name, actual_name, namelen + 1); 370 } else { 371 free(node->actual_name); 372 node->actual_name = NULL; 373 } 374 memcpy(node->name, name, namelen + 1); 375 node->namelen = namelen; 376 return 0; 377} 378 379static struct node *lookup_node_by_id_locked(struct fuse *fuse, __u64 nid) 380{ 381 if (nid == FUSE_ROOT_ID) { 382 return &fuse->root; 383 } else { 384 return id_to_ptr(nid); 385 } 386} 387 388static struct node* lookup_node_and_path_by_id_locked(struct fuse* fuse, __u64 nid, 389 char* buf, size_t bufsize) 390{ 391 struct node* node = lookup_node_by_id_locked(fuse, nid); 392 if (node && get_node_path_locked(node, buf, bufsize) < 0) { 393 node = NULL; 394 } 395 return node; 396} 397 398static struct node *lookup_child_by_name_locked(struct node *node, const char *name) 399{ 400 for (node = node->child; node; node = node->next) { 401 /* use exact string comparison, nodes that differ by case 402 * must be considered distinct even if they refer to the same 403 * underlying file as otherwise operations such as "mv x x" 404 * will not work because the source and target nodes are the same. */ 405 if (!strcmp(name, node->name)) { 406 return node; 407 } 408 } 409 return 0; 410} 411 412static struct node* acquire_or_create_child_locked( 413 struct fuse* fuse, struct node* parent, 414 const char* name, const char* actual_name) 415{ 416 struct node* child = lookup_child_by_name_locked(parent, name); 417 if (child) { 418 acquire_node_locked(child); 419 } else { 420 child = create_node_locked(fuse, parent, name, actual_name); 421 } 422 return child; 423} 424 425static void fuse_init(struct fuse *fuse, int fd, const char *source_path) 426{ 427 pthread_mutex_init(&fuse->lock, NULL); 428 429 fuse->fd = fd; 430 fuse->next_generation = 0; 431 432 memset(&fuse->root, 0, sizeof(fuse->root)); 433 fuse->root.nid = FUSE_ROOT_ID; /* 1 */ 434 fuse->root.refcount = 2; 435 fuse->root.namelen = strlen(source_path); 436 fuse->root.name = strdup(source_path); 437} 438 439static void fuse_status(struct fuse *fuse, __u64 unique, int err) 440{ 441 struct fuse_out_header hdr; 442 hdr.len = sizeof(hdr); 443 hdr.error = err; 444 hdr.unique = unique; 445 write(fuse->fd, &hdr, sizeof(hdr)); 446} 447 448static void fuse_reply(struct fuse *fuse, __u64 unique, void *data, int len) 449{ 450 struct fuse_out_header hdr; 451 struct iovec vec[2]; 452 int res; 453 454 hdr.len = len + sizeof(hdr); 455 hdr.error = 0; 456 hdr.unique = unique; 457 458 vec[0].iov_base = &hdr; 459 vec[0].iov_len = sizeof(hdr); 460 vec[1].iov_base = data; 461 vec[1].iov_len = len; 462 463 res = writev(fuse->fd, vec, 2); 464 if (res < 0) { 465 ERROR("*** REPLY FAILED *** %d\n", errno); 466 } 467} 468 469static int fuse_reply_entry(struct fuse* fuse, __u64 unique, 470 struct node* parent, const char* name, const char* actual_name, 471 const char* path) 472{ 473 struct node* node; 474 struct fuse_entry_out out; 475 struct stat s; 476 477 if (lstat(path, &s) < 0) { 478 return -errno; 479 } 480 481 pthread_mutex_lock(&fuse->lock); 482 node = acquire_or_create_child_locked(fuse, parent, name, actual_name); 483 if (!node) { 484 pthread_mutex_unlock(&fuse->lock); 485 return -ENOMEM; 486 } 487 memset(&out, 0, sizeof(out)); 488 attr_from_stat(&out.attr, &s, node->nid); 489 out.attr_valid = 10; 490 out.entry_valid = 10; 491 out.nodeid = node->nid; 492 out.generation = node->gen; 493 pthread_mutex_unlock(&fuse->lock); 494 fuse_reply(fuse, unique, &out, sizeof(out)); 495 return NO_STATUS; 496} 497 498static int fuse_reply_attr(struct fuse* fuse, __u64 unique, __u64 nid, 499 const char* path) 500{ 501 struct fuse_attr_out out; 502 struct stat s; 503 504 if (lstat(path, &s) < 0) { 505 return -errno; 506 } 507 memset(&out, 0, sizeof(out)); 508 attr_from_stat(&out.attr, &s, nid); 509 out.attr_valid = 10; 510 fuse_reply(fuse, unique, &out, sizeof(out)); 511 return NO_STATUS; 512} 513 514static int handle_lookup(struct fuse* fuse, struct fuse_handler* handler, 515 const struct fuse_in_header *hdr, const char* name) 516{ 517 struct node* parent_node; 518 char parent_path[PATH_MAX]; 519 char child_path[PATH_MAX]; 520 const char* actual_name; 521 522 pthread_mutex_lock(&fuse->lock); 523 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 524 parent_path, sizeof(parent_path)); 525 TRACE("[%d] LOOKUP %s @ %llx (%s)\n", handler->token, name, hdr->nodeid, 526 parent_node ? parent_node->name : "?"); 527 pthread_mutex_unlock(&fuse->lock); 528 529 if (!parent_node || !(actual_name = find_file_within(parent_path, name, 530 child_path, sizeof(child_path), 1))) { 531 return -ENOENT; 532 } 533 return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path); 534} 535 536static int handle_forget(struct fuse* fuse, struct fuse_handler* handler, 537 const struct fuse_in_header *hdr, const struct fuse_forget_in *req) 538{ 539 struct node* node; 540 541 pthread_mutex_lock(&fuse->lock); 542 node = lookup_node_by_id_locked(fuse, hdr->nodeid); 543 TRACE("[%d] FORGET #%lld @ %llx (%s)\n", handler->token, req->nlookup, 544 hdr->nodeid, node ? node->name : "?"); 545 if (node) { 546 __u64 n = req->nlookup; 547 while (n--) { 548 release_node_locked(node); 549 } 550 } 551 pthread_mutex_unlock(&fuse->lock); 552 return NO_STATUS; /* no reply */ 553} 554 555static int handle_getattr(struct fuse* fuse, struct fuse_handler* handler, 556 const struct fuse_in_header *hdr, const struct fuse_getattr_in *req) 557{ 558 struct node* node; 559 char path[PATH_MAX]; 560 561 pthread_mutex_lock(&fuse->lock); 562 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 563 TRACE("[%d] GETATTR flags=%x fh=%llx @ %llx (%s)\n", handler->token, 564 req->getattr_flags, req->fh, hdr->nodeid, node ? node->name : "?"); 565 pthread_mutex_unlock(&fuse->lock); 566 567 if (!node) { 568 return -ENOENT; 569 } 570 return fuse_reply_attr(fuse, hdr->unique, hdr->nodeid, path); 571} 572 573static int handle_setattr(struct fuse* fuse, struct fuse_handler* handler, 574 const struct fuse_in_header *hdr, const struct fuse_setattr_in *req) 575{ 576 struct node* node; 577 char path[PATH_MAX]; 578 struct timespec times[2]; 579 580 pthread_mutex_lock(&fuse->lock); 581 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 582 TRACE("[%d] SETATTR fh=%llx valid=%x @ %llx (%s)\n", handler->token, 583 req->fh, req->valid, hdr->nodeid, node ? node->name : "?"); 584 pthread_mutex_unlock(&fuse->lock); 585 586 if (!node) { 587 return -ENOENT; 588 } 589 590 /* XXX: incomplete implementation on purpose. 591 * chmod/chown should NEVER be implemented.*/ 592 593 if ((req->valid & FATTR_SIZE) && truncate(path, req->size) < 0) { 594 return -errno; 595 } 596 597 /* Handle changing atime and mtime. If FATTR_ATIME_and FATTR_ATIME_NOW 598 * are both set, then set it to the current time. Else, set it to the 599 * time specified in the request. Same goes for mtime. Use utimensat(2) 600 * as it allows ATIME and MTIME to be changed independently, and has 601 * nanosecond resolution which fuse also has. 602 */ 603 if (req->valid & (FATTR_ATIME | FATTR_MTIME)) { 604 times[0].tv_nsec = UTIME_OMIT; 605 times[1].tv_nsec = UTIME_OMIT; 606 if (req->valid & FATTR_ATIME) { 607 if (req->valid & FATTR_ATIME_NOW) { 608 times[0].tv_nsec = UTIME_NOW; 609 } else { 610 times[0].tv_sec = req->atime; 611 times[0].tv_nsec = req->atimensec; 612 } 613 } 614 if (req->valid & FATTR_MTIME) { 615 if (req->valid & FATTR_MTIME_NOW) { 616 times[1].tv_nsec = UTIME_NOW; 617 } else { 618 times[1].tv_sec = req->mtime; 619 times[1].tv_nsec = req->mtimensec; 620 } 621 } 622 TRACE("[%d] Calling utimensat on %s with atime %ld, mtime=%ld\n", 623 handler->token, path, times[0].tv_sec, times[1].tv_sec); 624 if (utimensat(-1, path, times, 0) < 0) { 625 return -errno; 626 } 627 } 628 return fuse_reply_attr(fuse, hdr->unique, hdr->nodeid, path); 629} 630 631static int handle_mknod(struct fuse* fuse, struct fuse_handler* handler, 632 const struct fuse_in_header* hdr, const struct fuse_mknod_in* req, const char* name) 633{ 634 struct node* parent_node; 635 char parent_path[PATH_MAX]; 636 char child_path[PATH_MAX]; 637 const char* actual_name; 638 639 pthread_mutex_lock(&fuse->lock); 640 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 641 parent_path, sizeof(parent_path)); 642 TRACE("[%d] MKNOD %s 0%o @ %llx (%s)\n", handler->token, 643 name, req->mode, hdr->nodeid, parent_node ? parent_node->name : "?"); 644 pthread_mutex_unlock(&fuse->lock); 645 646 if (!parent_node || !(actual_name = find_file_within(parent_path, name, 647 child_path, sizeof(child_path), 1))) { 648 return -ENOENT; 649 } 650 __u32 mode = (req->mode & (~0777)) | 0664; 651 if (mknod(child_path, mode, req->rdev) < 0) { 652 return -errno; 653 } 654 return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path); 655} 656 657static int handle_mkdir(struct fuse* fuse, struct fuse_handler* handler, 658 const struct fuse_in_header* hdr, const struct fuse_mkdir_in* req, const char* name) 659{ 660 struct node* parent_node; 661 char parent_path[PATH_MAX]; 662 char child_path[PATH_MAX]; 663 const char* actual_name; 664 665 pthread_mutex_lock(&fuse->lock); 666 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 667 parent_path, sizeof(parent_path)); 668 TRACE("[%d] MKDIR %s 0%o @ %llx (%s)\n", handler->token, 669 name, req->mode, hdr->nodeid, parent_node ? parent_node->name : "?"); 670 pthread_mutex_unlock(&fuse->lock); 671 672 if (!parent_node || !(actual_name = find_file_within(parent_path, name, 673 child_path, sizeof(child_path), 1))) { 674 return -ENOENT; 675 } 676 __u32 mode = (req->mode & (~0777)) | 0775; 677 if (mkdir(child_path, mode) < 0) { 678 return -errno; 679 } 680 return fuse_reply_entry(fuse, hdr->unique, parent_node, name, actual_name, child_path); 681} 682 683static int handle_unlink(struct fuse* fuse, struct fuse_handler* handler, 684 const struct fuse_in_header* hdr, const char* name) 685{ 686 struct node* parent_node; 687 char parent_path[PATH_MAX]; 688 char child_path[PATH_MAX]; 689 690 pthread_mutex_lock(&fuse->lock); 691 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 692 parent_path, sizeof(parent_path)); 693 TRACE("[%d] UNLINK %s @ %llx (%s)\n", handler->token, 694 name, hdr->nodeid, parent_node ? parent_node->name : "?"); 695 pthread_mutex_unlock(&fuse->lock); 696 697 if (!parent_node || !find_file_within(parent_path, name, 698 child_path, sizeof(child_path), 1)) { 699 return -ENOENT; 700 } 701 if (unlink(child_path) < 0) { 702 return -errno; 703 } 704 return 0; 705} 706 707static int handle_rmdir(struct fuse* fuse, struct fuse_handler* handler, 708 const struct fuse_in_header* hdr, const char* name) 709{ 710 struct node* parent_node; 711 char parent_path[PATH_MAX]; 712 char child_path[PATH_MAX]; 713 714 pthread_mutex_lock(&fuse->lock); 715 parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 716 parent_path, sizeof(parent_path)); 717 TRACE("[%d] RMDIR %s @ %llx (%s)\n", handler->token, 718 name, hdr->nodeid, parent_node ? parent_node->name : "?"); 719 pthread_mutex_unlock(&fuse->lock); 720 721 if (!parent_node || !find_file_within(parent_path, name, 722 child_path, sizeof(child_path), 1)) { 723 return -ENOENT; 724 } 725 if (rmdir(child_path) < 0) { 726 return -errno; 727 } 728 return 0; 729} 730 731static int handle_rename(struct fuse* fuse, struct fuse_handler* handler, 732 const struct fuse_in_header* hdr, const struct fuse_rename_in* req, 733 const char* old_name, const char* new_name) 734{ 735 struct node* old_parent_node; 736 struct node* new_parent_node; 737 struct node* child_node; 738 char old_parent_path[PATH_MAX]; 739 char new_parent_path[PATH_MAX]; 740 char old_child_path[PATH_MAX]; 741 char new_child_path[PATH_MAX]; 742 const char* new_actual_name; 743 int res; 744 745 pthread_mutex_lock(&fuse->lock); 746 old_parent_node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, 747 old_parent_path, sizeof(old_parent_path)); 748 new_parent_node = lookup_node_and_path_by_id_locked(fuse, req->newdir, 749 new_parent_path, sizeof(new_parent_path)); 750 TRACE("[%d] RENAME %s->%s @ %llx (%s) -> %llx (%s)\n", handler->token, 751 old_name, new_name, 752 hdr->nodeid, old_parent_node ? old_parent_node->name : "?", 753 req->newdir, new_parent_node ? new_parent_node->name : "?"); 754 if (!old_parent_node || !new_parent_node) { 755 res = -ENOENT; 756 goto lookup_error; 757 } 758 child_node = lookup_child_by_name_locked(old_parent_node, old_name); 759 if (!child_node || get_node_path_locked(child_node, 760 old_child_path, sizeof(old_child_path)) < 0) { 761 res = -ENOENT; 762 goto lookup_error; 763 } 764 acquire_node_locked(child_node); 765 pthread_mutex_unlock(&fuse->lock); 766 767 /* Special case for renaming a file where destination is same path 768 * differing only by case. In this case we don't want to look for a case 769 * insensitive match. This allows commands like "mv foo FOO" to work as expected. 770 */ 771 int search = old_parent_node != new_parent_node 772 || strcasecmp(old_name, new_name); 773 if (!(new_actual_name = find_file_within(new_parent_path, new_name, 774 new_child_path, sizeof(new_child_path), search))) { 775 res = -ENOENT; 776 goto io_error; 777 } 778 779 TRACE("[%d] RENAME %s->%s\n", handler->token, old_child_path, new_child_path); 780 res = rename(old_child_path, new_child_path); 781 if (res < 0) { 782 res = -errno; 783 goto io_error; 784 } 785 786 pthread_mutex_lock(&fuse->lock); 787 res = rename_node_locked(child_node, new_name, new_actual_name); 788 if (!res) { 789 remove_node_from_parent_locked(child_node); 790 add_node_to_parent_locked(child_node, new_parent_node); 791 } 792 goto done; 793 794io_error: 795 pthread_mutex_lock(&fuse->lock); 796done: 797 release_node_locked(child_node); 798lookup_error: 799 pthread_mutex_unlock(&fuse->lock); 800 return res; 801} 802 803static int handle_open(struct fuse* fuse, struct fuse_handler* handler, 804 const struct fuse_in_header* hdr, const struct fuse_open_in* req) 805{ 806 struct node* node; 807 char path[PATH_MAX]; 808 struct fuse_open_out out; 809 struct handle *h; 810 811 pthread_mutex_lock(&fuse->lock); 812 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 813 TRACE("[%d] OPEN 0%o @ %llx (%s)\n", handler->token, 814 req->flags, hdr->nodeid, node ? node->name : "?"); 815 pthread_mutex_unlock(&fuse->lock); 816 817 if (!node) { 818 return -ENOENT; 819 } 820 h = malloc(sizeof(*h)); 821 if (!h) { 822 return -ENOMEM; 823 } 824 TRACE("[%d] OPEN %s\n", handler->token, path); 825 h->fd = open(path, req->flags); 826 if (h->fd < 0) { 827 free(h); 828 return -errno; 829 } 830 out.fh = ptr_to_id(h); 831 out.open_flags = 0; 832 out.padding = 0; 833 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 834 return NO_STATUS; 835} 836 837static int handle_read(struct fuse* fuse, struct fuse_handler* handler, 838 const struct fuse_in_header* hdr, const struct fuse_read_in* req) 839{ 840 struct handle *h = id_to_ptr(req->fh); 841 __u64 unique = hdr->unique; 842 __u32 size = req->size; 843 __u64 offset = req->offset; 844 int res; 845 846 /* Don't access any other fields of hdr or req beyond this point, the read buffer 847 * overlaps the request buffer and will clobber data in the request. This 848 * saves us 128KB per request handler thread at the cost of this scary comment. */ 849 850 TRACE("[%d] READ %p(%d) %u@%llu\n", handler->token, 851 h, h->fd, size, offset); 852 if (size > sizeof(handler->read_buffer)) { 853 return -EINVAL; 854 } 855 res = pread64(h->fd, handler->read_buffer, size, offset); 856 if (res < 0) { 857 return -errno; 858 } 859 fuse_reply(fuse, unique, handler->read_buffer, res); 860 return NO_STATUS; 861} 862 863static int handle_write(struct fuse* fuse, struct fuse_handler* handler, 864 const struct fuse_in_header* hdr, const struct fuse_write_in* req, 865 const void* buffer) 866{ 867 struct fuse_write_out out; 868 struct handle *h = id_to_ptr(req->fh); 869 int res; 870 871 TRACE("[%d] WRITE %p(%d) %u@%llu\n", handler->token, 872 h, h->fd, req->size, req->offset); 873 res = pwrite64(h->fd, buffer, req->size, req->offset); 874 if (res < 0) { 875 return -errno; 876 } 877 out.size = res; 878 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 879 return NO_STATUS; 880} 881 882static int handle_statfs(struct fuse* fuse, struct fuse_handler* handler, 883 const struct fuse_in_header* hdr) 884{ 885 char path[PATH_MAX]; 886 struct statfs stat; 887 struct fuse_statfs_out out; 888 int res; 889 890 pthread_mutex_lock(&fuse->lock); 891 TRACE("[%d] STATFS\n", handler->token); 892 res = get_node_path_locked(&fuse->root, path, sizeof(path)); 893 pthread_mutex_unlock(&fuse->lock); 894 if (res < 0) { 895 return -ENOENT; 896 } 897 if (statfs(fuse->root.name, &stat) < 0) { 898 return -errno; 899 } 900 memset(&out, 0, sizeof(out)); 901 out.st.blocks = stat.f_blocks; 902 out.st.bfree = stat.f_bfree; 903 out.st.bavail = stat.f_bavail; 904 out.st.files = stat.f_files; 905 out.st.ffree = stat.f_ffree; 906 out.st.bsize = stat.f_bsize; 907 out.st.namelen = stat.f_namelen; 908 out.st.frsize = stat.f_frsize; 909 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 910 return NO_STATUS; 911} 912 913static int handle_release(struct fuse* fuse, struct fuse_handler* handler, 914 const struct fuse_in_header* hdr, const struct fuse_release_in* req) 915{ 916 struct handle *h = id_to_ptr(req->fh); 917 918 TRACE("[%d] RELEASE %p(%d)\n", handler->token, h, h->fd); 919 close(h->fd); 920 free(h); 921 return 0; 922} 923 924static int handle_fsync(struct fuse* fuse, struct fuse_handler* handler, 925 const struct fuse_in_header* hdr, const struct fuse_fsync_in* req) 926{ 927 int is_data_sync = req->fsync_flags & 1; 928 struct handle *h = id_to_ptr(req->fh); 929 int res; 930 931 TRACE("[%d] FSYNC %p(%d) is_data_sync=%d\n", handler->token, 932 h, h->fd, is_data_sync); 933 res = is_data_sync ? fdatasync(h->fd) : fsync(h->fd); 934 if (res < 0) { 935 return -errno; 936 } 937 return 0; 938} 939 940static int handle_flush(struct fuse* fuse, struct fuse_handler* handler, 941 const struct fuse_in_header* hdr) 942{ 943 TRACE("[%d] FLUSH\n", handler->token); 944 return 0; 945} 946 947static int handle_opendir(struct fuse* fuse, struct fuse_handler* handler, 948 const struct fuse_in_header* hdr, const struct fuse_open_in* req) 949{ 950 struct node* node; 951 char path[PATH_MAX]; 952 struct fuse_open_out out; 953 struct dirhandle *h; 954 955 pthread_mutex_lock(&fuse->lock); 956 node = lookup_node_and_path_by_id_locked(fuse, hdr->nodeid, path, sizeof(path)); 957 TRACE("[%d] OPENDIR @ %llx (%s)\n", handler->token, 958 hdr->nodeid, node ? node->name : "?"); 959 pthread_mutex_unlock(&fuse->lock); 960 961 if (!node) { 962 return -ENOENT; 963 } 964 h = malloc(sizeof(*h)); 965 if (!h) { 966 return -ENOMEM; 967 } 968 TRACE("[%d] OPENDIR %s\n", handler->token, path); 969 h->d = opendir(path); 970 if (!h->d) { 971 free(h); 972 return -errno; 973 } 974 out.fh = ptr_to_id(h); 975 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 976 return NO_STATUS; 977} 978 979static int handle_readdir(struct fuse* fuse, struct fuse_handler* handler, 980 const struct fuse_in_header* hdr, const struct fuse_read_in* req) 981{ 982 char buffer[8192]; 983 struct fuse_dirent *fde = (struct fuse_dirent*) buffer; 984 struct dirent *de; 985 struct dirhandle *h = id_to_ptr(req->fh); 986 987 TRACE("[%d] READDIR %p\n", handler->token, h); 988 if (req->offset == 0) { 989 /* rewinddir() might have been called above us, so rewind here too */ 990 TRACE("[%d] calling rewinddir()\n", handler->token); 991 rewinddir(h->d); 992 } 993 de = readdir(h->d); 994 if (!de) { 995 return 0; 996 } 997 fde->ino = FUSE_UNKNOWN_INO; 998 /* increment the offset so we can detect when rewinddir() seeks back to the beginning */ 999 fde->off = req->offset + 1; 1000 fde->type = de->d_type; 1001 fde->namelen = strlen(de->d_name); 1002 memcpy(fde->name, de->d_name, fde->namelen + 1); 1003 fuse_reply(fuse, hdr->unique, fde, 1004 FUSE_DIRENT_ALIGN(sizeof(struct fuse_dirent) + fde->namelen)); 1005 return NO_STATUS; 1006} 1007 1008static int handle_releasedir(struct fuse* fuse, struct fuse_handler* handler, 1009 const struct fuse_in_header* hdr, const struct fuse_release_in* req) 1010{ 1011 struct dirhandle *h = id_to_ptr(req->fh); 1012 1013 TRACE("[%d] RELEASEDIR %p\n", handler->token, h); 1014 closedir(h->d); 1015 free(h); 1016 return 0; 1017} 1018 1019static int handle_init(struct fuse* fuse, struct fuse_handler* handler, 1020 const struct fuse_in_header* hdr, const struct fuse_init_in* req) 1021{ 1022 struct fuse_init_out out; 1023 1024 TRACE("[%d] INIT ver=%d.%d maxread=%d flags=%x\n", 1025 handler->token, req->major, req->minor, req->max_readahead, req->flags); 1026 out.major = FUSE_KERNEL_VERSION; 1027 out.minor = FUSE_KERNEL_MINOR_VERSION; 1028 out.max_readahead = req->max_readahead; 1029 out.flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES; 1030 out.max_background = 32; 1031 out.congestion_threshold = 32; 1032 out.max_write = MAX_WRITE; 1033 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 1034 return NO_STATUS; 1035} 1036 1037static int handle_fuse_request(struct fuse *fuse, struct fuse_handler* handler, 1038 const struct fuse_in_header *hdr, const void *data, size_t data_len) 1039{ 1040 switch (hdr->opcode) { 1041 case FUSE_LOOKUP: { /* bytez[] -> entry_out */ 1042 const char* name = data; 1043 return handle_lookup(fuse, handler, hdr, name); 1044 } 1045 1046 case FUSE_FORGET: { 1047 const struct fuse_forget_in *req = data; 1048 return handle_forget(fuse, handler, hdr, req); 1049 } 1050 1051 case FUSE_GETATTR: { /* getattr_in -> attr_out */ 1052 const struct fuse_getattr_in *req = data; 1053 return handle_getattr(fuse, handler, hdr, req); 1054 } 1055 1056 case FUSE_SETATTR: { /* setattr_in -> attr_out */ 1057 const struct fuse_setattr_in *req = data; 1058 return handle_setattr(fuse, handler, hdr, req); 1059 } 1060 1061// case FUSE_READLINK: 1062// case FUSE_SYMLINK: 1063 case FUSE_MKNOD: { /* mknod_in, bytez[] -> entry_out */ 1064 const struct fuse_mknod_in *req = data; 1065 const char *name = ((const char*) data) + sizeof(*req); 1066 return handle_mknod(fuse, handler, hdr, req, name); 1067 } 1068 1069 case FUSE_MKDIR: { /* mkdir_in, bytez[] -> entry_out */ 1070 const struct fuse_mkdir_in *req = data; 1071 const char *name = ((const char*) data) + sizeof(*req); 1072 return handle_mkdir(fuse, handler, hdr, req, name); 1073 } 1074 1075 case FUSE_UNLINK: { /* bytez[] -> */ 1076 const char* name = data; 1077 return handle_unlink(fuse, handler, hdr, name); 1078 } 1079 1080 case FUSE_RMDIR: { /* bytez[] -> */ 1081 const char* name = data; 1082 return handle_rmdir(fuse, handler, hdr, name); 1083 } 1084 1085 case FUSE_RENAME: { /* rename_in, oldname, newname -> */ 1086 const struct fuse_rename_in *req = data; 1087 const char *old_name = ((const char*) data) + sizeof(*req); 1088 const char *new_name = old_name + strlen(old_name) + 1; 1089 return handle_rename(fuse, handler, hdr, req, old_name, new_name); 1090 } 1091 1092// case FUSE_LINK: 1093 case FUSE_OPEN: { /* open_in -> open_out */ 1094 const struct fuse_open_in *req = data; 1095 return handle_open(fuse, handler, hdr, req); 1096 } 1097 1098 case FUSE_READ: { /* read_in -> byte[] */ 1099 const struct fuse_read_in *req = data; 1100 return handle_read(fuse, handler, hdr, req); 1101 } 1102 1103 case FUSE_WRITE: { /* write_in, byte[write_in.size] -> write_out */ 1104 const struct fuse_write_in *req = data; 1105 const void* buffer = (const __u8*)data + sizeof(*req); 1106 return handle_write(fuse, handler, hdr, req, buffer); 1107 } 1108 1109 case FUSE_STATFS: { /* getattr_in -> attr_out */ 1110 return handle_statfs(fuse, handler, hdr); 1111 } 1112 1113 case FUSE_RELEASE: { /* release_in -> */ 1114 const struct fuse_release_in *req = data; 1115 return handle_release(fuse, handler, hdr, req); 1116 } 1117 1118 case FUSE_FSYNC: { 1119 const struct fuse_fsync_in *req = data; 1120 return handle_fsync(fuse, handler, hdr, req); 1121 } 1122 1123// case FUSE_SETXATTR: 1124// case FUSE_GETXATTR: 1125// case FUSE_LISTXATTR: 1126// case FUSE_REMOVEXATTR: 1127 case FUSE_FLUSH: { 1128 return handle_flush(fuse, handler, hdr); 1129 } 1130 1131 case FUSE_OPENDIR: { /* open_in -> open_out */ 1132 const struct fuse_open_in *req = data; 1133 return handle_opendir(fuse, handler, hdr, req); 1134 } 1135 1136 case FUSE_READDIR: { 1137 const struct fuse_read_in *req = data; 1138 return handle_readdir(fuse, handler, hdr, req); 1139 } 1140 1141 case FUSE_RELEASEDIR: { /* release_in -> */ 1142 const struct fuse_release_in *req = data; 1143 return handle_releasedir(fuse, handler, hdr, req); 1144 } 1145 1146// case FUSE_FSYNCDIR: 1147 case FUSE_INIT: { /* init_in -> init_out */ 1148 const struct fuse_init_in *req = data; 1149 return handle_init(fuse, handler, hdr, req); 1150 } 1151 1152 default: { 1153 TRACE("[%d] NOTIMPL op=%d uniq=%llx nid=%llx\n", 1154 handler->token, hdr->opcode, hdr->unique, hdr->nodeid); 1155 return -ENOSYS; 1156 } 1157 } 1158} 1159 1160static void handle_fuse_requests(struct fuse_handler* handler) 1161{ 1162 struct fuse* fuse = handler->fuse; 1163 for (;;) { 1164 ssize_t len = read(fuse->fd, 1165 handler->request_buffer, sizeof(handler->request_buffer)); 1166 if (len < 0) { 1167 if (errno != EINTR) { 1168 ERROR("[%d] handle_fuse_requests: errno=%d\n", handler->token, errno); 1169 } 1170 continue; 1171 } 1172 1173 if ((size_t)len < sizeof(struct fuse_in_header)) { 1174 ERROR("[%d] request too short: len=%zu\n", handler->token, (size_t)len); 1175 continue; 1176 } 1177 1178 const struct fuse_in_header *hdr = (void*)handler->request_buffer; 1179 if (hdr->len != (size_t)len) { 1180 ERROR("[%d] malformed header: len=%zu, hdr->len=%u\n", 1181 handler->token, (size_t)len, hdr->len); 1182 continue; 1183 } 1184 1185 const void *data = handler->request_buffer + sizeof(struct fuse_in_header); 1186 size_t data_len = len - sizeof(struct fuse_in_header); 1187 __u64 unique = hdr->unique; 1188 int res = handle_fuse_request(fuse, handler, hdr, data, data_len); 1189 1190 /* We do not access the request again after this point because the underlying 1191 * buffer storage may have been reused while processing the request. */ 1192 1193 if (res != NO_STATUS) { 1194 if (res) { 1195 TRACE("[%d] ERROR %d\n", handler->token, res); 1196 } 1197 fuse_status(fuse, unique, res); 1198 } 1199 } 1200} 1201 1202static void* start_handler(void* data) 1203{ 1204 struct fuse_handler* handler = data; 1205 handle_fuse_requests(handler); 1206 return NULL; 1207} 1208 1209static int ignite_fuse(struct fuse* fuse, int num_threads) 1210{ 1211 struct fuse_handler* handlers; 1212 int i; 1213 1214 handlers = malloc(num_threads * sizeof(struct fuse_handler)); 1215 if (!handlers) { 1216 ERROR("cannot allocate storage for threads"); 1217 return -ENOMEM; 1218 } 1219 1220 for (i = 0; i < num_threads; i++) { 1221 handlers[i].fuse = fuse; 1222 handlers[i].token = i; 1223 } 1224 1225 for (i = 1; i < num_threads; i++) { 1226 pthread_t thread; 1227 int res = pthread_create(&thread, NULL, start_handler, &handlers[i]); 1228 if (res) { 1229 ERROR("failed to start thread #%d, error=%d", i, res); 1230 goto quit; 1231 } 1232 } 1233 handle_fuse_requests(&handlers[0]); 1234 ERROR("terminated prematurely"); 1235 1236 /* don't bother killing all of the other threads or freeing anything, 1237 * should never get here anyhow */ 1238quit: 1239 exit(1); 1240} 1241 1242static int usage() 1243{ 1244 ERROR("usage: sdcard [-t<threads>] <source_path> <dest_path> <uid> <gid>\n" 1245 " -t<threads>: specify number of threads to use, default -t%d\n" 1246 "\n", DEFAULT_NUM_THREADS); 1247 return 1; 1248} 1249 1250static int run(const char* source_path, const char* dest_path, uid_t uid, gid_t gid, 1251 int num_threads) { 1252 int fd; 1253 char opts[256]; 1254 int res; 1255 struct fuse fuse; 1256 1257 /* cleanup from previous instance, if necessary */ 1258 umount2(dest_path, 2); 1259 1260 fd = open("/dev/fuse", O_RDWR); 1261 if (fd < 0){ 1262 ERROR("cannot open fuse device (error %d)\n", errno); 1263 return -1; 1264 } 1265 1266 snprintf(opts, sizeof(opts), 1267 "fd=%i,rootmode=40000,default_permissions,allow_other,user_id=%d,group_id=%d", 1268 fd, uid, gid); 1269 1270 res = mount("/dev/fuse", dest_path, "fuse", MS_NOSUID | MS_NODEV, opts); 1271 if (res < 0) { 1272 ERROR("cannot mount fuse filesystem (error %d)\n", errno); 1273 goto error; 1274 } 1275 1276 res = setgid(gid); 1277 if (res < 0) { 1278 ERROR("cannot setgid (error %d)\n", errno); 1279 goto error; 1280 } 1281 1282 res = setuid(uid); 1283 if (res < 0) { 1284 ERROR("cannot setuid (error %d)\n", errno); 1285 goto error; 1286 } 1287 1288 fuse_init(&fuse, fd, source_path); 1289 1290 umask(0); 1291 res = ignite_fuse(&fuse, num_threads); 1292 1293 /* we do not attempt to umount the file system here because we are no longer 1294 * running as the root user */ 1295 1296error: 1297 close(fd); 1298 return res; 1299} 1300 1301int main(int argc, char **argv) 1302{ 1303 int res; 1304 const char *source_path = NULL; 1305 const char *dest_path = NULL; 1306 uid_t uid = 0; 1307 gid_t gid = 0; 1308 int num_threads = DEFAULT_NUM_THREADS; 1309 int i; 1310 struct rlimit rlim; 1311 1312 for (i = 1; i < argc; i++) { 1313 char* arg = argv[i]; 1314 if (!strncmp(arg, "-t", 2)) 1315 num_threads = strtoul(arg + 2, 0, 10); 1316 else if (!source_path) 1317 source_path = arg; 1318 else if (!dest_path) 1319 dest_path = arg; 1320 else if (!uid) { 1321 char* endptr = NULL; 1322 errno = 0; 1323 uid = strtoul(arg, &endptr, 10); 1324 if (*endptr != '\0' || errno != 0) { 1325 ERROR("Invalid uid"); 1326 return usage(); 1327 } 1328 } else if (!gid) { 1329 char* endptr = NULL; 1330 errno = 0; 1331 gid = strtoul(arg, &endptr, 10); 1332 if (*endptr != '\0' || errno != 0) { 1333 ERROR("Invalid gid"); 1334 return usage(); 1335 } 1336 } else { 1337 ERROR("too many arguments\n"); 1338 return usage(); 1339 } 1340 } 1341 1342 if (!source_path) { 1343 ERROR("no source path specified\n"); 1344 return usage(); 1345 } 1346 if (!dest_path) { 1347 ERROR("no dest path specified\n"); 1348 return usage(); 1349 } 1350 if (!uid || !gid) { 1351 ERROR("uid and gid must be nonzero\n"); 1352 return usage(); 1353 } 1354 if (num_threads < 1) { 1355 ERROR("number of threads must be at least 1\n"); 1356 return usage(); 1357 } 1358 1359 rlim.rlim_cur = 8192; 1360 rlim.rlim_max = 8192; 1361 if (setrlimit(RLIMIT_NOFILE, &rlim)) { 1362 ERROR("Error setting RLIMIT_NOFILE, errno = %d\n", errno); 1363 } 1364 1365 res = run(source_path, dest_path, uid, gid, num_threads); 1366 return res < 0 ? 1 : 0; 1367} 1368