sdcard.c revision fc1e1a0ab48a88dc7e9a93f65da5e6458de622af
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 31#include <private/android_filesystem_config.h> 32 33#include "fuse.h" 34 35/* README 36 * 37 * What is this? 38 * 39 * sdcard is a program that uses FUSE to emulate FAT-on-sdcard style 40 * directory permissions (all files are given fixed owner, group, and 41 * permissions at creation, owner, group, and permissions are not 42 * changeable, symlinks and hardlinks are not createable, etc. 43 * 44 * usage: sdcard <path> <uid> <gid> 45 * 46 * It must be run as root, but will change to uid/gid as soon as it 47 * mounts a filesystem on /storage/sdcard. It will refuse to run if uid or 48 * gid are zero. 49 * 50 * 51 * Things I believe to be true: 52 * 53 * - ops that return a fuse_entry (LOOKUP, MKNOD, MKDIR, LINK, SYMLINK, 54 * CREAT) must bump that node's refcount 55 * - don't forget that FORGET can forget multiple references (req->nlookup) 56 * - if an op that returns a fuse_entry fails writing the reply to the 57 * kernel, you must rollback the refcount to reflect the reference the 58 * kernel did not actually acquire 59 * 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#define MOUNT_POINT "/storage/sdcard0" 75 76/* Maximum number of bytes to write in one request. */ 77#define MAX_WRITE (256 * 1024) 78 79/* Maximum number of bytes to read in one request. */ 80#define MAX_READ (128 * 1024) 81 82/* Largest possible request. 83 * The request size is bounded by the maximum size of a FUSE_WRITE request because it has 84 * the largest possible data payload. */ 85#define MAX_REQUEST_SIZE (sizeof(struct fuse_in_header) + sizeof(struct fuse_write_in) + MAX_WRITE) 86 87struct handle { 88 struct node *node; 89 int fd; 90}; 91 92struct dirhandle { 93 struct node *node; 94 DIR *d; 95}; 96 97struct node { 98 __u64 nid; 99 __u64 gen; 100 101 struct node *next; /* per-dir sibling list */ 102 struct node *child; /* first contained file by this dir */ 103 struct node *all; /* global node list */ 104 struct node *parent; /* containing directory */ 105 106 __u32 refcount; 107 __u32 namelen; 108 109 char *name; 110 /* If non-null, this is the real name of the file in the underlying storage. 111 * This may differ from the field "name" only by case. 112 * strlen(actual_name) will always equal strlen(name), so it is safe to use 113 * namelen for both fields. 114 */ 115 char *actual_name; 116}; 117 118/* Global data structure shared by all fuse handlers. */ 119struct fuse { 120 __u64 next_generation; 121 __u64 next_node_id; 122 123 int fd; 124 125 struct node *all; 126 127 struct node root; 128 char rootpath[PATH_MAX]; 129}; 130 131/* Private data used by a single fuse handler. */ 132struct fuse_handler { 133 /* To save memory, we never use the contents of the request buffer and the read 134 * buffer at the same time. This allows us to share the underlying storage. */ 135 union { 136 __u8 request_buffer[MAX_REQUEST_SIZE]; 137 __u8 read_buffer[MAX_READ]; 138 }; 139}; 140 141#define NO_CASE_SENSITIVE_MATCH 0 142#define CASE_SENSITIVE_MATCH 1 143 144/* 145 * Get the real-life absolute path to a node. 146 * node: start at this node 147 * buf: storage for returned string 148 * name: append this string to path if set 149 */ 150char *do_node_get_path(struct node *node, char *buf, const char *name, int match_case_insensitive) 151{ 152 struct node *in_node = node; 153 const char *in_name = name; 154 char *out = buf + PATH_MAX - 1; 155 int len; 156 out[0] = 0; 157 158 if (name) { 159 len = strlen(name); 160 goto start; 161 } 162 163 while (node) { 164 name = (node->actual_name ? node->actual_name : node->name); 165 len = node->namelen; 166 node = node->parent; 167 start: 168 if ((len + 1) > (out - buf)) 169 return 0; 170 out -= len; 171 memcpy(out, name, len); 172 /* avoid double slash at beginning of path */ 173 if (out[0] != '/') { 174 out --; 175 out[0] = '/'; 176 } 177 } 178 179 /* If we are searching for a file within node (rather than computing node's path) 180 * and fail, then we need to look for a case insensitive match. 181 */ 182 if (in_name && match_case_insensitive && access(out, F_OK) != 0) { 183 char *path, buffer[PATH_MAX]; 184 DIR* dir; 185 struct dirent* entry; 186 path = do_node_get_path(in_node, buffer, NULL, NO_CASE_SENSITIVE_MATCH); 187 dir = opendir(path); 188 if (!dir) { 189 ERROR("opendir %s failed: %s", path, strerror(errno)); 190 return out; 191 } 192 193 while ((entry = readdir(dir))) { 194 if (!strcasecmp(entry->d_name, in_name)) { 195 /* we have a match - replace the name */ 196 len = strlen(in_name); 197 memcpy(buf + PATH_MAX - len - 1, entry->d_name, len); 198 break; 199 } 200 } 201 closedir(dir); 202 } 203 204 return out; 205} 206 207char *node_get_path(struct node *node, char *buf, const char *name) 208{ 209 /* We look for case insensitive matches by default */ 210 return do_node_get_path(node, buf, name, CASE_SENSITIVE_MATCH); 211} 212 213void attr_from_stat(struct fuse_attr *attr, struct stat *s) 214{ 215 attr->ino = s->st_ino; 216 attr->size = s->st_size; 217 attr->blocks = s->st_blocks; 218 attr->atime = s->st_atime; 219 attr->mtime = s->st_mtime; 220 attr->ctime = s->st_ctime; 221 attr->atimensec = s->st_atime_nsec; 222 attr->mtimensec = s->st_mtime_nsec; 223 attr->ctimensec = s->st_ctime_nsec; 224 attr->mode = s->st_mode; 225 attr->nlink = s->st_nlink; 226 227 /* force permissions to something reasonable: 228 * world readable 229 * writable by the sdcard group 230 */ 231 if (attr->mode & 0100) { 232 attr->mode = (attr->mode & (~0777)) | 0775; 233 } else { 234 attr->mode = (attr->mode & (~0777)) | 0664; 235 } 236 237 /* all files owned by root.sdcard */ 238 attr->uid = 0; 239 attr->gid = AID_SDCARD_RW; 240} 241 242int node_get_attr(struct node *node, struct fuse_attr *attr) 243{ 244 int res; 245 struct stat s; 246 char *path, buffer[PATH_MAX]; 247 248 path = node_get_path(node, buffer, 0); 249 res = lstat(path, &s); 250 if (res < 0) { 251 ERROR("lstat('%s') errno %d\n", path, errno); 252 return -1; 253 } 254 255 attr_from_stat(attr, &s); 256 attr->ino = node->nid; 257 258 return 0; 259} 260 261static void add_node_to_parent(struct node *node, struct node *parent) { 262 node->parent = parent; 263 node->next = parent->child; 264 parent->child = node; 265 parent->refcount++; 266} 267 268/* Check to see if our parent directory already has a file with a name 269 * that differs only by case. If we find one, store it in the actual_name 270 * field so node_get_path will map it to this file in the underlying storage. 271 */ 272static void node_find_actual_name(struct node *node) 273{ 274 char *path, buffer[PATH_MAX]; 275 const char *node_name = node->name; 276 DIR* dir; 277 struct dirent* entry; 278 279 if (!node->parent) return; 280 281 path = node_get_path(node->parent, buffer, 0); 282 dir = opendir(path); 283 if (!dir) { 284 ERROR("opendir %s failed: %s", path, strerror(errno)); 285 return; 286 } 287 288 while ((entry = readdir(dir))) { 289 const char *test_name = entry->d_name; 290 if (strcmp(test_name, node_name) && !strcasecmp(test_name, node_name)) { 291 /* we have a match - differs but only by case */ 292 node->actual_name = strdup(test_name); 293 if (!node->actual_name) { 294 ERROR("strdup failed - out of memory\n"); 295 exit(1); 296 } 297 break; 298 } 299 } 300 closedir(dir); 301} 302 303struct node *node_create(struct node *parent, const char *name, __u64 nid, __u64 gen) 304{ 305 struct node *node; 306 int namelen = strlen(name); 307 308 node = calloc(1, sizeof(struct node)); 309 if (node == 0) { 310 return 0; 311 } 312 node->name = malloc(namelen + 1); 313 if (node->name == 0) { 314 free(node); 315 return 0; 316 } 317 318 node->nid = nid; 319 node->gen = gen; 320 add_node_to_parent(node, parent); 321 memcpy(node->name, name, namelen + 1); 322 node->namelen = namelen; 323 node_find_actual_name(node); 324 return node; 325} 326 327static char *rename_node(struct node *node, const char *name) 328{ 329 node->namelen = strlen(name); 330 char *newname = realloc(node->name, node->namelen + 1); 331 if (newname == 0) 332 return 0; 333 node->name = newname; 334 memcpy(node->name, name, node->namelen + 1); 335 node_find_actual_name(node); 336 return node->name; 337} 338 339void fuse_init(struct fuse *fuse, int fd, const char *path) 340{ 341 fuse->fd = fd; 342 fuse->next_node_id = 2; 343 fuse->next_generation = 0; 344 345 fuse->all = &fuse->root; 346 347 memset(&fuse->root, 0, sizeof(fuse->root)); 348 fuse->root.nid = FUSE_ROOT_ID; /* 1 */ 349 fuse->root.refcount = 2; 350 rename_node(&fuse->root, path); 351} 352 353static inline void *id_to_ptr(__u64 nid) 354{ 355 return (void *) (uintptr_t) nid; 356} 357 358static inline __u64 ptr_to_id(void *ptr) 359{ 360 return (__u64) (uintptr_t) ptr; 361} 362 363 364struct node *lookup_by_inode(struct fuse *fuse, __u64 nid) 365{ 366 if (!nid) { 367 return NULL; 368 } else if (nid == FUSE_ROOT_ID) { 369 return &fuse->root; 370 } else { 371 return id_to_ptr(nid); 372 } 373} 374 375struct node *lookup_child_by_name(struct node *node, const char *name) 376{ 377 for (node = node->child; node; node = node->next) { 378 if (!strcmp(name, node->name)) { 379 return node; 380 } 381 } 382 return 0; 383} 384 385struct node *lookup_child_by_inode(struct node *node, __u64 nid) 386{ 387 for (node = node->child; node; node = node->next) { 388 if (node->nid == nid) { 389 return node; 390 } 391 } 392 return 0; 393} 394 395static void dec_refcount(struct node *node) { 396 if (node->refcount > 0) { 397 node->refcount--; 398 TRACE("dec_refcount %p(%s) -> %d\n", node, node->name, node->refcount); 399 } else { 400 ERROR("Zero refcnt %p\n", node); 401 } 402 } 403 404static struct node *remove_child(struct node *parent, __u64 nid) 405{ 406 struct node *prev = 0; 407 struct node *node; 408 409 for (node = parent->child; node; node = node->next) { 410 if (node->nid == nid) { 411 if (prev) { 412 prev->next = node->next; 413 } else { 414 parent->child = node->next; 415 } 416 node->next = 0; 417 node->parent = 0; 418 dec_refcount(parent); 419 return node; 420 } 421 prev = node; 422 } 423 return 0; 424} 425 426struct node *node_lookup(struct fuse *fuse, struct node *parent, const char *name, 427 struct fuse_attr *attr) 428{ 429 int res; 430 struct stat s; 431 char *path, buffer[PATH_MAX]; 432 struct node *node; 433 434 path = node_get_path(parent, buffer, name); 435 /* XXX error? */ 436 437 res = lstat(path, &s); 438 if (res < 0) 439 return 0; 440 441 node = lookup_child_by_name(parent, name); 442 if (!node) { 443 node = node_create(parent, name, fuse->next_node_id++, fuse->next_generation++); 444 if (!node) 445 return 0; 446 node->nid = ptr_to_id(node); 447 node->all = fuse->all; 448 fuse->all = node; 449 } 450 451 attr_from_stat(attr, &s); 452 attr->ino = node->nid; 453 454 return node; 455} 456 457void node_release(struct node *node) 458{ 459 TRACE("RELEASE %p (%s) rc=%d\n", node, node->name, node->refcount); 460 dec_refcount(node); 461 if (node->refcount == 0) { 462 if (node->parent->child == node) { 463 node->parent->child = node->parent->child->next; 464 } else { 465 struct node *node2; 466 467 node2 = node->parent->child; 468 while (node2->next != node) 469 node2 = node2->next; 470 node2->next = node->next; 471 } 472 473 TRACE("DESTROY %p (%s)\n", node, node->name); 474 475 node_release(node->parent); 476 477 node->parent = 0; 478 node->next = 0; 479 480 /* TODO: remove debugging - poison memory */ 481 memset(node->name, 0xef, node->namelen); 482 free(node->name); 483 free(node->actual_name); 484 memset(node, 0xfc, sizeof(*node)); 485 free(node); 486 } 487} 488 489void fuse_status(struct fuse *fuse, __u64 unique, int err) 490{ 491 struct fuse_out_header hdr; 492 hdr.len = sizeof(hdr); 493 hdr.error = err; 494 hdr.unique = unique; 495 if (err) { 496// ERROR("*** %d ***\n", err); 497 } 498 write(fuse->fd, &hdr, sizeof(hdr)); 499} 500 501void fuse_reply(struct fuse *fuse, __u64 unique, void *data, int len) 502{ 503 struct fuse_out_header hdr; 504 struct iovec vec[2]; 505 int res; 506 507 hdr.len = len + sizeof(hdr); 508 hdr.error = 0; 509 hdr.unique = unique; 510 511 vec[0].iov_base = &hdr; 512 vec[0].iov_len = sizeof(hdr); 513 vec[1].iov_base = data; 514 vec[1].iov_len = len; 515 516 res = writev(fuse->fd, vec, 2); 517 if (res < 0) { 518 ERROR("*** REPLY FAILED *** %d\n", errno); 519 } 520} 521 522static void lookup_entry(struct fuse* fuse, struct fuse_handler* handler, 523 __u64 unique, struct node* parent_node, const char* name) 524{ 525 struct fuse_entry_out out; 526 struct node* node; 527 528 memset(&out, 0, sizeof(out)); 529 node = node_lookup(fuse, parent_node, name, &out.attr); 530 if (!node) { 531 fuse_status(fuse, unique, -ENOENT); 532 return; 533 } 534 535 node->refcount++; 536 TRACE("ACQUIRE %p (%s) rc=%d\n", node, node->name, node->refcount); 537 out.nodeid = node->nid; 538 out.generation = node->gen; 539 out.entry_valid = 10; 540 out.attr_valid = 10; 541 542 fuse_reply(fuse, unique, &out, sizeof(out)); 543} 544 545static void handle_lookup(struct fuse* fuse, struct fuse_handler* handler, 546 const struct fuse_in_header *hdr, const char* name) 547{ 548 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 549 550 TRACE("LOOKUP %s @ %llx (%s)\n", name, hdr->nodeid, node ? node->name : "?"); 551 if (!node) { 552 fuse_status(fuse, hdr->unique, -ENOENT); 553 return; 554 } 555 556 lookup_entry(fuse, handler, hdr->unique, node, name); 557} 558 559static void handle_forget(struct fuse* fuse, struct fuse_handler* handler, 560 const struct fuse_in_header *hdr, const struct fuse_forget_in *req) 561{ 562 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 563 __u64 n = req->nlookup; 564 565 TRACE("FORGET #%lld @ %llx (%s)\n", n, hdr->nodeid, node ? node->name : "?"); 566 if (!node) { 567 fuse_status(fuse, hdr->unique, -ENOENT); 568 return; 569 } 570 571 while (n--) { 572 node_release(node); 573 } 574 /* no reply */ 575} 576 577static void handle_getaddr(struct fuse* fuse, struct fuse_handler* handler, 578 const struct fuse_in_header *hdr, const struct fuse_getattr_in *req) 579{ 580 struct fuse_attr_out out; 581 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 582 583 TRACE("GETATTR flags=%x fh=%llx @ %llx (%s)\n", req->getattr_flags, req->fh, 584 hdr->nodeid, node ? node->name : "?"); 585 if (!node) { 586 fuse_status(fuse, hdr->unique, -ENOENT); 587 return; 588 } 589 590 memset(&out, 0, sizeof(out)); 591 node_get_attr(node, &out.attr); 592 out.attr_valid = 10; 593 594 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 595} 596 597static void handle_setattr(struct fuse* fuse, struct fuse_handler* handler, 598 const struct fuse_in_header *hdr, const struct fuse_setattr_in *req) 599{ 600 struct fuse_attr_out out; 601 char *path, buffer[PATH_MAX]; 602 int res = 0; 603 struct timespec times[2]; 604 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 605 606 TRACE("SETATTR fh=%llx valid=%x @ %llx (%s)\n", req->fh, req->valid, 607 hdr->nodeid, node ? node->name : "?"); 608 if (!node) { 609 fuse_status(fuse, hdr->unique, -ENOENT); 610 return; 611 } 612 613 /* XXX: incomplete implementation on purpose. chmod/chown 614 * should NEVER be implemented.*/ 615 616 path = node_get_path(node, buffer, 0); 617 if (req->valid & FATTR_SIZE) 618 res = truncate(path, req->size); 619 if (res < 0) { 620 fuse_status(fuse, hdr->unique, -errno); 621 return; 622 } 623 624 /* Handle changing atime and mtime. If FATTR_ATIME_and FATTR_ATIME_NOW 625 * are both set, then set it to the current time. Else, set it to the 626 * time specified in the request. Same goes for mtime. Use utimensat(2) 627 * as it allows ATIME and MTIME to be changed independently, and has 628 * nanosecond resolution which fuse also has. 629 */ 630 if (req->valid & (FATTR_ATIME | FATTR_MTIME)) { 631 times[0].tv_nsec = UTIME_OMIT; 632 times[1].tv_nsec = UTIME_OMIT; 633 if (req->valid & FATTR_ATIME) { 634 if (req->valid & FATTR_ATIME_NOW) { 635 times[0].tv_nsec = UTIME_NOW; 636 } else { 637 times[0].tv_sec = req->atime; 638 times[0].tv_nsec = req->atimensec; 639 } 640 } 641 if (req->valid & FATTR_MTIME) { 642 if (req->valid & FATTR_MTIME_NOW) { 643 times[1].tv_nsec = UTIME_NOW; 644 } else { 645 times[1].tv_sec = req->mtime; 646 times[1].tv_nsec = req->mtimensec; 647 } 648 } 649 TRACE("Calling utimensat on %s with atime %ld, mtime=%ld\n", path, times[0].tv_sec, times[1].tv_sec); 650 res = utimensat(-1, path, times, 0); 651 if (res < 0) { 652 fuse_status(fuse, hdr->unique, -errno); 653 return; 654 } 655 } 656 657 memset(&out, 0, sizeof(out)); 658 node_get_attr(node, &out.attr); 659 out.attr_valid = 10; 660 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 661} 662 663static void handle_mknod(struct fuse* fuse, struct fuse_handler* handler, 664 const struct fuse_in_header* hdr, const struct fuse_mknod_in* req, const char* name) 665{ 666 char *path, buffer[PATH_MAX]; 667 int res; 668 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 669 670 TRACE("MKNOD %s @ %llx (%s)\n", name, hdr->nodeid, node ? node->name : "?"); 671 if (!node) { 672 fuse_status(fuse, hdr->unique, -ENOENT); 673 return; 674 } 675 676 path = node_get_path(node, buffer, name); 677 678 __u32 mode = (req->mode & (~0777)) | 0664; 679 res = mknod(path, mode, req->rdev); /* XXX perm?*/ 680 if (res < 0) { 681 fuse_status(fuse, hdr->unique, -errno); 682 return; 683 } 684 685 lookup_entry(fuse, handler, hdr->unique, node, name); 686} 687 688static void handle_mkdir(struct fuse* fuse, struct fuse_handler* handler, 689 const struct fuse_in_header* hdr, const struct fuse_mkdir_in* req, const char* name) 690{ 691 struct fuse_entry_out out; 692 char *path, buffer[PATH_MAX]; 693 int res; 694 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 695 696 TRACE("MKDIR %s 0%o @ %llx (%s)\n", name, req->mode, hdr->nodeid, node ? node->name : "?"); 697 if (!node) { 698 fuse_status(fuse, hdr->unique, -ENOENT); 699 return; 700 } 701 702 path = node_get_path(node, buffer, name); 703 704 __u32 mode = (req->mode & (~0777)) | 0775; 705 res = mkdir(path, mode); 706 if (res < 0) { 707 fuse_status(fuse, hdr->unique, -errno); 708 return; 709 } 710 711 lookup_entry(fuse, handler, hdr->unique, node, name); 712} 713 714static void handle_unlink(struct fuse* fuse, struct fuse_handler* handler, 715 const struct fuse_in_header* hdr, const char* name) 716{ 717 char *path, buffer[PATH_MAX]; 718 int res; 719 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 720 721 TRACE("UNLINK %s @ %llx (%s)\n", name, hdr->nodeid, node ? node->name : "?"); 722 if (!node) { 723 fuse_status(fuse, hdr->unique, -ENOENT); 724 return; 725 } 726 727 path = node_get_path(node, buffer, name); 728 res = unlink(path); 729 fuse_status(fuse, hdr->unique, res ? -errno : 0); 730} 731 732static void handle_rmdir(struct fuse* fuse, struct fuse_handler* handler, 733 const struct fuse_in_header* hdr, const char* name) 734{ 735 char *path, buffer[PATH_MAX]; 736 int res; 737 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 738 739 TRACE("RMDIR %s @ %llx (%s)\n", name, hdr->nodeid, node ? node->name : "?"); 740 if (!node) { 741 fuse_status(fuse, hdr->unique, -ENOENT); 742 return; 743 } 744 745 path = node_get_path(node, buffer, name); 746 res = rmdir(path); 747 fuse_status(fuse, hdr->unique, res ? -errno : 0); 748} 749 750static void handle_rename(struct fuse* fuse, struct fuse_handler* handler, 751 const struct fuse_in_header* hdr, const struct fuse_rename_in* req, 752 const char* oldname, const char* newname) 753{ 754 char *oldpath, oldbuffer[PATH_MAX]; 755 char *newpath, newbuffer[PATH_MAX]; 756 struct node *target; 757 struct node *newparent; 758 int res; 759 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 760 761 TRACE("RENAME %s->%s @ %llx (%s)\n", oldname, newname, hdr->nodeid, node ? node->name : "?"); 762 if (!node) { 763 fuse_status(fuse, hdr->unique, -ENOENT); 764 return; 765 } 766 767 target = lookup_child_by_name(node, oldname); 768 if (!target) { 769 fuse_status(fuse, hdr->unique, -ENOENT); 770 return; 771 } 772 oldpath = node_get_path(node, oldbuffer, oldname); 773 774 newparent = lookup_by_inode(fuse, req->newdir); 775 if (!newparent) { 776 fuse_status(fuse, hdr->unique, -ENOENT); 777 return; 778 } 779 if (newparent == node) { 780 /* Special case for renaming a file where destination 781 * is same path differing only by case. 782 * In this case we don't want to look for a case insensitive match. 783 * This allows commands like "mv foo FOO" to work as expected. 784 */ 785 newpath = do_node_get_path(newparent, newbuffer, newname, NO_CASE_SENSITIVE_MATCH); 786 } else { 787 newpath = node_get_path(newparent, newbuffer, newname); 788 } 789 790 if (!remove_child(node, target->nid)) { 791 ERROR("RENAME remove_child not found"); 792 fuse_status(fuse, hdr->unique, -ENOENT); 793 return; 794 } 795 if (!rename_node(target, newname)) { 796 fuse_status(fuse, hdr->unique, -ENOMEM); 797 return; 798 } 799 add_node_to_parent(target, newparent); 800 801 res = rename(oldpath, newpath); 802 TRACE("RENAME result %d\n", res); 803 804 fuse_status(fuse, hdr->unique, res ? -errno : 0); 805} 806 807static void handle_open(struct fuse* fuse, struct fuse_handler* handler, 808 const struct fuse_in_header* hdr, const struct fuse_open_in* req) 809{ 810 struct fuse_open_out out; 811 char *path, buffer[PATH_MAX]; 812 struct handle *h; 813 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 814 815 h = malloc(sizeof(*h)); 816 if (!h) { 817 fuse_status(fuse, hdr->unique, -ENOMEM); 818 return; 819 } 820 821 TRACE("OPEN 0%o fh=%p @ %llx (%s)\n", req->flags, h, hdr->nodeid, node ? node->name : "?"); 822 if (!node) { 823 fuse_status(fuse, hdr->unique, -ENOENT); 824 return; 825 } 826 827 path = node_get_path(node, buffer, 0); 828 h->fd = open(path, req->flags); 829 if (h->fd < 0) { 830 ERROR("ERROR\n"); 831 fuse_status(fuse, hdr->unique, -errno); 832 free(h); 833 return; 834 } 835 out.fh = ptr_to_id(h); 836 out.open_flags = 0; 837 out.padding = 0; 838 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 839} 840 841static void handle_read(struct fuse* fuse, struct fuse_handler* handler, 842 const struct fuse_in_header* hdr, const struct fuse_read_in* req) 843{ 844 struct handle *h = id_to_ptr(req->fh); 845 __u64 unique = hdr->unique; 846 __u32 size = req->size; 847 __u64 offset = req->offset; 848 /* Don't access any other fields of hdr or req beyond this point, the read buffer 849 * overlaps the request buffer and will clobber data in the request. This 850 * saves us 128KB per request handler thread at the cost of this scary comment. */ 851 int res; 852 TRACE("READ %p(%d) %u@%llu\n", h, h->fd, size, offset); 853 if (size > sizeof(handler->read_buffer)) { 854 fuse_status(fuse, unique, -EINVAL); 855 return; 856 } 857 res = pread64(h->fd, handler->read_buffer, size, offset); 858 if (res < 0) { 859 fuse_status(fuse, unique, -errno); 860 return; 861 } 862 fuse_reply(fuse, unique, handler->read_buffer, res); 863} 864 865static void handle_write(struct fuse* fuse, struct fuse_handler* handler, 866 const struct fuse_in_header* hdr, const struct fuse_write_in* req, 867 const void* buffer) 868{ 869 struct fuse_write_out out; 870 struct handle *h = id_to_ptr(req->fh); 871 int res; 872 TRACE("WRITE %p(%d) %u@%llu\n", h, h->fd, req->size, req->offset); 873 res = pwrite64(h->fd, buffer, req->size, req->offset); 874 if (res < 0) { 875 fuse_status(fuse, hdr->unique, -errno); 876 return; 877 } 878 out.size = res; 879 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 880} 881 882static void handle_statfs(struct fuse* fuse, struct fuse_handler* handler, 883 const struct fuse_in_header* hdr) 884{ 885 struct statfs stat; 886 struct fuse_statfs_out out; 887 int res; 888 889 TRACE("STATFS\n"); 890 891 if (statfs(fuse->root.name, &stat)) { 892 fuse_status(fuse, hdr->unique, -errno); 893 return; 894 } 895 896 memset(&out, 0, sizeof(out)); 897 out.st.blocks = stat.f_blocks; 898 out.st.bfree = stat.f_bfree; 899 out.st.bavail = stat.f_bavail; 900 out.st.files = stat.f_files; 901 out.st.ffree = stat.f_ffree; 902 out.st.bsize = stat.f_bsize; 903 out.st.namelen = stat.f_namelen; 904 out.st.frsize = stat.f_frsize; 905 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 906} 907 908static void handle_release(struct fuse* fuse, struct fuse_handler* handler, 909 const struct fuse_in_header* hdr, const struct fuse_release_in* req) 910{ 911 struct handle *h = id_to_ptr(req->fh); 912 TRACE("RELEASE %p(%d)\n", h, h->fd); 913 close(h->fd); 914 free(h); 915 fuse_status(fuse, hdr->unique, 0); 916} 917 918static void handle_fsync(struct fuse* fuse, struct fuse_handler* handler, 919 const struct fuse_in_header* hdr, const struct fuse_fsync_in* req) 920{ 921 int is_data_sync = req->fsync_flags & 1; 922 struct handle *h = id_to_ptr(req->fh); 923 int res; 924 TRACE("FSYNC %p(%d) is_data_sync=%d\n", h, h->fd, is_data_sync); 925 res = is_data_sync ? fdatasync(h->fd) : fsync(h->fd); 926 if (res < 0) { 927 fuse_status(fuse, hdr->unique, -errno); 928 return; 929 } 930 fuse_status(fuse, hdr->unique, 0); 931} 932 933static void handle_flush(struct fuse* fuse, struct fuse_handler* handler, 934 const struct fuse_in_header* hdr) 935{ 936 fuse_status(fuse, hdr->unique, 0); 937} 938 939static void handle_opendir(struct fuse* fuse, struct fuse_handler* handler, 940 const struct fuse_in_header* hdr, const struct fuse_open_in* req) 941{ 942 struct fuse_open_out out; 943 char *path, buffer[PATH_MAX]; 944 struct dirhandle *h; 945 struct node* node = lookup_by_inode(fuse, hdr->nodeid); 946 947 TRACE("OPENDIR @ %llx (%s)\n", hdr->nodeid, node ? node->name : "?"); 948 if (!node) { 949 fuse_status(fuse, hdr->unique, -ENOENT); 950 return; 951 } 952 953 h = malloc(sizeof(*h)); 954 if (!h) { 955 fuse_status(fuse, hdr->unique, -ENOMEM); 956 return; 957 } 958 959 path = node_get_path(node, buffer, 0); 960 h->d = opendir(path); 961 if (h->d == 0) { 962 ERROR("ERROR\n"); 963 fuse_status(fuse, hdr->unique, -errno); 964 free(h); 965 return; 966 } 967 out.fh = ptr_to_id(h); 968 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 969} 970 971static void handle_readdir(struct fuse* fuse, struct fuse_handler* handler, 972 const struct fuse_in_header* hdr, const struct fuse_read_in* req) 973{ 974 char buffer[8192]; 975 struct fuse_dirent *fde = (struct fuse_dirent*) buffer; 976 struct dirent *de; 977 struct dirhandle *h = id_to_ptr(req->fh); 978 TRACE("READDIR %p\n", h); 979 if (req->offset == 0) { 980 /* rewinddir() might have been called above us, so rewind here too */ 981 TRACE("calling rewinddir()\n"); 982 rewinddir(h->d); 983 } 984 de = readdir(h->d); 985 if (!de) { 986 fuse_status(fuse, hdr->unique, 0); 987 return; 988 } 989 fde->ino = FUSE_UNKNOWN_INO; 990 /* increment the offset so we can detect when rewinddir() seeks back to the beginning */ 991 fde->off = req->offset + 1; 992 fde->type = de->d_type; 993 fde->namelen = strlen(de->d_name); 994 memcpy(fde->name, de->d_name, fde->namelen + 1); 995 fuse_reply(fuse, hdr->unique, fde, 996 FUSE_DIRENT_ALIGN(sizeof(struct fuse_dirent) + fde->namelen)); 997} 998 999static void handle_releasedir(struct fuse* fuse, struct fuse_handler* handler, 1000 const struct fuse_in_header* hdr, const struct fuse_release_in* req) 1001{ 1002 struct dirhandle *h = id_to_ptr(req->fh); 1003 TRACE("RELEASEDIR %p\n",h); 1004 closedir(h->d); 1005 free(h); 1006 fuse_status(fuse, hdr->unique, 0); 1007} 1008 1009static void handle_init(struct fuse* fuse, struct fuse_handler* handler, 1010 const struct fuse_in_header* hdr, const struct fuse_init_in* req) 1011{ 1012 struct fuse_init_out out; 1013 1014 TRACE("INIT ver=%d.%d maxread=%d flags=%x\n", 1015 req->major, req->minor, req->max_readahead, req->flags); 1016 1017 out.major = FUSE_KERNEL_VERSION; 1018 out.minor = FUSE_KERNEL_MINOR_VERSION; 1019 out.max_readahead = req->max_readahead; 1020 out.flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES; 1021 out.max_background = 32; 1022 out.congestion_threshold = 32; 1023 out.max_write = MAX_WRITE; 1024 1025 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 1026} 1027 1028static void handle_fuse_request(struct fuse *fuse, struct fuse_handler* handler, 1029 const struct fuse_in_header *hdr, const void *data, size_t data_len) 1030{ 1031 switch (hdr->opcode) { 1032 case FUSE_LOOKUP: { /* bytez[] -> entry_out */ 1033 const char* name = data; 1034 handle_lookup(fuse, handler, hdr, name); 1035 return; 1036 } 1037 1038 case FUSE_FORGET: { 1039 const struct fuse_forget_in *req = data; 1040 handle_forget(fuse, handler, hdr, req); 1041 return; 1042 } 1043 1044 case FUSE_GETATTR: { /* getattr_in -> attr_out */ 1045 const struct fuse_getattr_in *req = data; 1046 handle_getaddr(fuse, handler, hdr, req); 1047 return; 1048 } 1049 1050 case FUSE_SETATTR: { /* setattr_in -> attr_out */ 1051 const struct fuse_setattr_in *req = data; 1052 handle_setattr(fuse, handler, hdr, req); 1053 return; 1054 } 1055 1056// case FUSE_READLINK: 1057// case FUSE_SYMLINK: 1058 case FUSE_MKNOD: { /* mknod_in, bytez[] -> entry_out */ 1059 const struct fuse_mknod_in *req = data; 1060 const char *name = ((const char*) data) + sizeof(*req); 1061 handle_mknod(fuse, handler, hdr, req, name); 1062 return; 1063 } 1064 1065 case FUSE_MKDIR: { /* mkdir_in, bytez[] -> entry_out */ 1066 const struct fuse_mkdir_in *req = data; 1067 const char *name = ((const char*) data) + sizeof(*req); 1068 handle_mkdir(fuse, handler, hdr, req, name); 1069 return; 1070 } 1071 1072 case FUSE_UNLINK: { /* bytez[] -> */ 1073 const char* name = data; 1074 handle_unlink(fuse, handler, hdr, name); 1075 return; 1076 } 1077 1078 case FUSE_RMDIR: { /* bytez[] -> */ 1079 const char* name = data; 1080 handle_rmdir(fuse, handler, hdr, name); 1081 return; 1082 } 1083 1084 case FUSE_RENAME: { /* rename_in, oldname, newname -> */ 1085 const struct fuse_rename_in *req = data; 1086 const char *oldname = ((const char*) data) + sizeof(*req); 1087 const char *newname = oldname + strlen(oldname) + 1; 1088 handle_rename(fuse, handler, hdr, req, oldname, newname); 1089 return; 1090 } 1091 1092// case FUSE_LINK: 1093 case FUSE_OPEN: { /* open_in -> open_out */ 1094 const struct fuse_open_in *req = data; 1095 handle_open(fuse, handler, hdr, req); 1096 return; 1097 } 1098 1099 case FUSE_READ: { /* read_in -> byte[] */ 1100 const struct fuse_read_in *req = data; 1101 handle_read(fuse, handler, hdr, req); 1102 return; 1103 } 1104 1105 case FUSE_WRITE: { /* write_in, byte[write_in.size] -> write_out */ 1106 const struct fuse_write_in *req = data; 1107 const void* buffer = (const __u8*)data + sizeof(*req); 1108 handle_write(fuse, handler, hdr, req, buffer); 1109 return; 1110 } 1111 1112 case FUSE_STATFS: { /* getattr_in -> attr_out */ 1113 handle_statfs(fuse, handler, hdr); 1114 return; 1115 } 1116 1117 case FUSE_RELEASE: { /* release_in -> */ 1118 const struct fuse_release_in *req = data; 1119 handle_release(fuse, handler, hdr, req); 1120 return; 1121 } 1122 1123 case FUSE_FSYNC: { 1124 const struct fuse_fsync_in *req = data; 1125 handle_fsync(fuse, handler, hdr, req); 1126 return; 1127 } 1128 1129// case FUSE_SETXATTR: 1130// case FUSE_GETXATTR: 1131// case FUSE_LISTXATTR: 1132// case FUSE_REMOVEXATTR: 1133 case FUSE_FLUSH: { 1134 handle_flush(fuse, handler, hdr); 1135 return; 1136 } 1137 1138 case FUSE_OPENDIR: { /* open_in -> open_out */ 1139 const struct fuse_open_in *req = data; 1140 handle_opendir(fuse, handler, hdr, req); 1141 return; 1142 } 1143 1144 case FUSE_READDIR: { 1145 const struct fuse_read_in *req = data; 1146 handle_readdir(fuse, handler, hdr, req); 1147 return; 1148 } 1149 1150 case FUSE_RELEASEDIR: { /* release_in -> */ 1151 const struct fuse_release_in *req = data; 1152 handle_releasedir(fuse, handler, hdr, req); 1153 return; 1154 } 1155 1156// case FUSE_FSYNCDIR: 1157 case FUSE_INIT: { /* init_in -> init_out */ 1158 const struct fuse_init_in *req = data; 1159 handle_init(fuse, handler, hdr, req); 1160 return; 1161 } 1162 1163 default: { 1164 ERROR("NOTIMPL op=%d uniq=%llx nid=%llx\n", 1165 hdr->opcode, hdr->unique, hdr->nodeid); 1166 fuse_status(fuse, hdr->unique, -ENOSYS); 1167 break; 1168 } 1169 } 1170} 1171 1172static void handle_fuse_requests(struct fuse *fuse, struct fuse_handler* handler) 1173{ 1174 for (;;) { 1175 ssize_t len = read(fuse->fd, handler->request_buffer, sizeof(handler->request_buffer)); 1176 if (len < 0) { 1177 if (errno == EINTR) 1178 continue; 1179 ERROR("handle_fuse_requests: errno=%d\n", errno); 1180 return; 1181 } 1182 1183 if ((size_t)len < sizeof(struct fuse_in_header)) { 1184 ERROR("request too short: len=%zu\n", (size_t)len); 1185 return; 1186 } 1187 1188 const struct fuse_in_header *hdr = (void*)handler->request_buffer; 1189 if (hdr->len != (size_t)len) { 1190 ERROR("malformed header: len=%zu, hdr->len=%u\n", (size_t)len, hdr->len); 1191 return; 1192 } 1193 1194 const void *data = handler->request_buffer + sizeof(struct fuse_in_header); 1195 size_t data_len = len - sizeof(struct fuse_in_header); 1196 handle_fuse_request(fuse, handler, hdr, data, data_len); 1197 1198 /* We do not access the request again after this point because the underlying 1199 * buffer storage may have been reused while processing the request. */ 1200 } 1201} 1202 1203static int ignite_fuse(struct fuse* fuse) 1204{ 1205 /* use only one handler thread for now */ 1206 struct fuse_handler handler; 1207 handle_fuse_requests(fuse, &handler); 1208 return 0; 1209} 1210 1211static int usage() 1212{ 1213 ERROR("usage: sdcard <path> <uid> <gid>\n\n"); 1214 return 1; 1215} 1216 1217static int run(const char* path, uid_t uid, gid_t gid) 1218{ 1219 int fd; 1220 char opts[256]; 1221 int res; 1222 struct fuse fuse; 1223 1224 /* cleanup from previous instance, if necessary */ 1225 umount2(MOUNT_POINT, 2); 1226 1227 fd = open("/dev/fuse", O_RDWR); 1228 if (fd < 0){ 1229 ERROR("cannot open fuse device (error %d)\n", errno); 1230 return -1; 1231 } 1232 1233 snprintf(opts, sizeof(opts), 1234 "fd=%i,rootmode=40000,default_permissions,allow_other,user_id=%d,group_id=%d", 1235 fd, uid, gid); 1236 1237 res = mount("/dev/fuse", MOUNT_POINT, "fuse", MS_NOSUID | MS_NODEV, opts); 1238 if (res < 0) { 1239 ERROR("cannot mount fuse filesystem (error %d)\n", errno); 1240 goto error; 1241 } 1242 1243 res = setgid(gid); 1244 if (res < 0) { 1245 ERROR("cannot setgid (error %d)\n", errno); 1246 goto error; 1247 } 1248 1249 res = setuid(uid); 1250 if (res < 0) { 1251 ERROR("cannot setuid (error %d)\n", errno); 1252 goto error; 1253 } 1254 1255 fuse_init(&fuse, fd, path); 1256 1257 umask(0); 1258 res = ignite_fuse(&fuse); 1259 1260 /* we do not attempt to umount the file system here because we are no longer 1261 * running as the root user */ 1262 1263error: 1264 close(fd); 1265 return res; 1266} 1267 1268int main(int argc, char **argv) 1269{ 1270 int fd; 1271 int res; 1272 const char *path = NULL; 1273 uid_t uid = 0; 1274 gid_t gid = 0; 1275 int i; 1276 1277 for (i = 1; i < argc; i++) { 1278 char* arg = argv[i]; 1279 if (!path) 1280 path = arg; 1281 else if (!uid) 1282 uid = strtoul(arg, 0, 10); 1283 else if (!gid) 1284 gid = strtoul(arg, 0, 10); 1285 else { 1286 ERROR("too many arguments\n"); 1287 return usage(); 1288 } 1289 } 1290 1291 if (!path) { 1292 ERROR("no path specified\n"); 1293 return usage(); 1294 } 1295 if (!uid || !gid) { 1296 ERROR("uid and gid must be nonzero\n"); 1297 return usage(); 1298 } 1299 1300 res = run(path, uid, gid); 1301 return res < 0 ? 1 : 0; 1302} 1303