sdcard.c revision 29bdc876e498a193f61ea3bdadce5bf8a35cb250
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 <ctype.h> 29 30#include <private/android_filesystem_config.h> 31 32#include "fuse.h" 33 34/* README 35 * 36 * What is this? 37 * 38 * sdcard is a program that uses FUSE to emulate FAT-on-sdcard style 39 * directory permissions (all files are given fixed owner, group, and 40 * permissions at creation, owner, group, and permissions are not 41 * changeable, symlinks and hardlinks are not createable, etc. 42 * 43 * usage: sdcard <path> <uid> <gid> 44 * 45 * It must be run as root, but will change to uid/gid as soon as it 46 * mounts a filesystem on /storage/sdcard. It will refuse to run if uid or 47 * gid are zero. 48 * 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 61#define FUSE_TRACE 0 62 63#if FUSE_TRACE 64#define TRACE(x...) fprintf(stderr,x) 65#else 66#define TRACE(x...) do {} while (0) 67#endif 68 69#define ERROR(x...) fprintf(stderr,x) 70 71#define FUSE_UNKNOWN_INO 0xffffffff 72 73#define MOUNT_POINT "/storage/sdcard0" 74 75struct handle { 76 struct node *node; 77 int fd; 78}; 79 80struct dirhandle { 81 struct node *node; 82 DIR *d; 83}; 84 85struct node { 86 __u64 nid; 87 __u64 gen; 88 89 struct node *next; /* per-dir sibling list */ 90 struct node *child; /* first contained file by this dir */ 91 struct node *all; /* global node list */ 92 struct node *parent; /* containing directory */ 93 94 __u32 refcount; 95 __u32 namelen; 96 97 char *name; 98 /* If non-null, this is the real name of the file in the underlying storage. 99 * This may differ from the field "name" only by case. 100 * strlen(actual_name) will always equal strlen(name), so it is safe to use 101 * namelen for both fields. 102 */ 103 char *actual_name; 104}; 105 106struct fuse { 107 __u64 next_generation; 108 __u64 next_node_id; 109 110 int fd; 111 112 struct node *all; 113 114 struct node root; 115 char rootpath[1024]; 116}; 117 118#define PATH_BUFFER_SIZE 1024 119 120#define NO_CASE_SENSITIVE_MATCH 0 121#define CASE_SENSITIVE_MATCH 1 122 123/* 124 * Get the real-life absolute path to a node. 125 * node: start at this node 126 * buf: storage for returned string 127 * name: append this string to path if set 128 */ 129char *do_node_get_path(struct node *node, char *buf, const char *name, int match_case_insensitive) 130{ 131 struct node *in_node = node; 132 const char *in_name = name; 133 char *out = buf + PATH_BUFFER_SIZE - 1; 134 int len; 135 out[0] = 0; 136 137 if (name) { 138 len = strlen(name); 139 goto start; 140 } 141 142 while (node) { 143 name = (node->actual_name ? node->actual_name : node->name); 144 len = node->namelen; 145 node = node->parent; 146 start: 147 if ((len + 1) > (out - buf)) 148 return 0; 149 out -= len; 150 memcpy(out, name, len); 151 /* avoid double slash at beginning of path */ 152 if (out[0] != '/') { 153 out --; 154 out[0] = '/'; 155 } 156 } 157 158 /* If we are searching for a file within node (rather than computing node's path) 159 * and fail, then we need to look for a case insensitive match. 160 */ 161 if (in_name && match_case_insensitive && access(out, F_OK) != 0) { 162 char *path, buffer[PATH_BUFFER_SIZE]; 163 DIR* dir; 164 struct dirent* entry; 165 path = do_node_get_path(in_node, buffer, NULL, NO_CASE_SENSITIVE_MATCH); 166 dir = opendir(path); 167 if (!dir) { 168 ERROR("opendir %s failed: %s", path, strerror(errno)); 169 return out; 170 } 171 172 while ((entry = readdir(dir))) { 173 if (!strcasecmp(entry->d_name, in_name)) { 174 /* we have a match - replace the name */ 175 len = strlen(in_name); 176 memcpy(buf + PATH_BUFFER_SIZE - len - 1, entry->d_name, len); 177 break; 178 } 179 } 180 closedir(dir); 181 } 182 183 return out; 184} 185 186char *node_get_path(struct node *node, char *buf, const char *name) 187{ 188 /* We look for case insensitive matches by default */ 189 return do_node_get_path(node, buf, name, CASE_SENSITIVE_MATCH); 190} 191 192void attr_from_stat(struct fuse_attr *attr, struct stat *s) 193{ 194 attr->ino = s->st_ino; 195 attr->size = s->st_size; 196 attr->blocks = s->st_blocks; 197 attr->atime = s->st_atime; 198 attr->mtime = s->st_mtime; 199 attr->ctime = s->st_ctime; 200 attr->atimensec = s->st_atime_nsec; 201 attr->mtimensec = s->st_mtime_nsec; 202 attr->ctimensec = s->st_ctime_nsec; 203 attr->mode = s->st_mode; 204 attr->nlink = s->st_nlink; 205 206 /* force permissions to something reasonable: 207 * world readable 208 * writable by the sdcard group 209 */ 210 if (attr->mode & 0100) { 211 attr->mode = (attr->mode & (~0777)) | 0775; 212 } else { 213 attr->mode = (attr->mode & (~0777)) | 0664; 214 } 215 216 /* all files owned by root.sdcard */ 217 attr->uid = 0; 218 attr->gid = AID_SDCARD_RW; 219} 220 221int node_get_attr(struct node *node, struct fuse_attr *attr) 222{ 223 int res; 224 struct stat s; 225 char *path, buffer[PATH_BUFFER_SIZE]; 226 227 path = node_get_path(node, buffer, 0); 228 res = lstat(path, &s); 229 if (res < 0) { 230 ERROR("lstat('%s') errno %d\n", path, errno); 231 return -1; 232 } 233 234 attr_from_stat(attr, &s); 235 attr->ino = node->nid; 236 237 return 0; 238} 239 240static void add_node_to_parent(struct node *node, struct node *parent) { 241 node->parent = parent; 242 node->next = parent->child; 243 parent->child = node; 244 parent->refcount++; 245} 246 247/* Check to see if our parent directory already has a file with a name 248 * that differs only by case. If we find one, store it in the actual_name 249 * field so node_get_path will map it to this file in the underlying storage. 250 */ 251static void node_find_actual_name(struct node *node) 252{ 253 char *path, buffer[PATH_BUFFER_SIZE]; 254 const char *node_name = node->name; 255 DIR* dir; 256 struct dirent* entry; 257 258 if (!node->parent) return; 259 260 path = node_get_path(node->parent, buffer, 0); 261 dir = opendir(path); 262 if (!dir) { 263 ERROR("opendir %s failed: %s", path, strerror(errno)); 264 return; 265 } 266 267 while ((entry = readdir(dir))) { 268 const char *test_name = entry->d_name; 269 if (strcmp(test_name, node_name) && !strcasecmp(test_name, node_name)) { 270 /* we have a match - differs but only by case */ 271 node->actual_name = strdup(test_name); 272 if (!node->actual_name) { 273 ERROR("strdup failed - out of memory\n"); 274 exit(1); 275 } 276 break; 277 } 278 } 279 closedir(dir); 280} 281 282struct node *node_create(struct node *parent, const char *name, __u64 nid, __u64 gen) 283{ 284 struct node *node; 285 int namelen = strlen(name); 286 287 node = calloc(1, sizeof(struct node)); 288 if (node == 0) { 289 return 0; 290 } 291 node->name = malloc(namelen + 1); 292 if (node->name == 0) { 293 free(node); 294 return 0; 295 } 296 297 node->nid = nid; 298 node->gen = gen; 299 add_node_to_parent(node, parent); 300 memcpy(node->name, name, namelen + 1); 301 node->namelen = namelen; 302 node_find_actual_name(node); 303 return node; 304} 305 306static char *rename_node(struct node *node, const char *name) 307{ 308 node->namelen = strlen(name); 309 char *newname = realloc(node->name, node->namelen + 1); 310 if (newname == 0) 311 return 0; 312 node->name = newname; 313 memcpy(node->name, name, node->namelen + 1); 314 node_find_actual_name(node); 315 return node->name; 316} 317 318void fuse_init(struct fuse *fuse, int fd, const char *path) 319{ 320 fuse->fd = fd; 321 fuse->next_node_id = 2; 322 fuse->next_generation = 0; 323 324 fuse->all = &fuse->root; 325 326 memset(&fuse->root, 0, sizeof(fuse->root)); 327 fuse->root.nid = FUSE_ROOT_ID; /* 1 */ 328 fuse->root.refcount = 2; 329 rename_node(&fuse->root, path); 330} 331 332static inline void *id_to_ptr(__u64 nid) 333{ 334 return (void *) nid; 335} 336 337static inline __u64 ptr_to_id(void *ptr) 338{ 339 return (__u64) ptr; 340} 341 342 343struct node *lookup_by_inode(struct fuse *fuse, __u64 nid) 344{ 345 if (nid == FUSE_ROOT_ID) { 346 return &fuse->root; 347 } else { 348 return id_to_ptr(nid); 349 } 350} 351 352struct node *lookup_child_by_name(struct node *node, const char *name) 353{ 354 for (node = node->child; node; node = node->next) { 355 if (!strcmp(name, node->name)) { 356 return node; 357 } 358 } 359 return 0; 360} 361 362struct node *lookup_child_by_inode(struct node *node, __u64 nid) 363{ 364 for (node = node->child; node; node = node->next) { 365 if (node->nid == nid) { 366 return node; 367 } 368 } 369 return 0; 370} 371 372static void dec_refcount(struct node *node) { 373 if (node->refcount > 0) { 374 node->refcount--; 375 TRACE("dec_refcount %p(%s) -> %d\n", node, node->name, node->refcount); 376 } else { 377 ERROR("Zero refcnt %p\n", node); 378 } 379 } 380 381static struct node *remove_child(struct node *parent, __u64 nid) 382{ 383 struct node *prev = 0; 384 struct node *node; 385 386 for (node = parent->child; node; node = node->next) { 387 if (node->nid == nid) { 388 if (prev) { 389 prev->next = node->next; 390 } else { 391 parent->child = node->next; 392 } 393 node->next = 0; 394 node->parent = 0; 395 dec_refcount(parent); 396 return node; 397 } 398 prev = node; 399 } 400 return 0; 401} 402 403struct node *node_lookup(struct fuse *fuse, struct node *parent, const char *name, 404 struct fuse_attr *attr) 405{ 406 int res; 407 struct stat s; 408 char *path, buffer[PATH_BUFFER_SIZE]; 409 struct node *node; 410 411 path = node_get_path(parent, buffer, name); 412 /* XXX error? */ 413 414 res = lstat(path, &s); 415 if (res < 0) 416 return 0; 417 418 node = lookup_child_by_name(parent, name); 419 if (!node) { 420 node = node_create(parent, name, fuse->next_node_id++, fuse->next_generation++); 421 if (!node) 422 return 0; 423 node->nid = ptr_to_id(node); 424 node->all = fuse->all; 425 fuse->all = node; 426 } 427 428 attr_from_stat(attr, &s); 429 attr->ino = node->nid; 430 431 return node; 432} 433 434void node_release(struct node *node) 435{ 436 TRACE("RELEASE %p (%s) rc=%d\n", node, node->name, node->refcount); 437 dec_refcount(node); 438 if (node->refcount == 0) { 439 if (node->parent->child == node) { 440 node->parent->child = node->parent->child->next; 441 } else { 442 struct node *node2; 443 444 node2 = node->parent->child; 445 while (node2->next != node) 446 node2 = node2->next; 447 node2->next = node->next; 448 } 449 450 TRACE("DESTROY %p (%s)\n", node, node->name); 451 452 node_release(node->parent); 453 454 node->parent = 0; 455 node->next = 0; 456 457 /* TODO: remove debugging - poison memory */ 458 memset(node->name, 0xef, node->namelen); 459 free(node->name); 460 free(node->actual_name); 461 memset(node, 0xfc, sizeof(*node)); 462 free(node); 463 } 464} 465 466void fuse_status(struct fuse *fuse, __u64 unique, int err) 467{ 468 struct fuse_out_header hdr; 469 hdr.len = sizeof(hdr); 470 hdr.error = err; 471 hdr.unique = unique; 472 if (err) { 473// ERROR("*** %d ***\n", err); 474 } 475 write(fuse->fd, &hdr, sizeof(hdr)); 476} 477 478void fuse_reply(struct fuse *fuse, __u64 unique, void *data, int len) 479{ 480 struct fuse_out_header hdr; 481 struct iovec vec[2]; 482 int res; 483 484 hdr.len = len + sizeof(hdr); 485 hdr.error = 0; 486 hdr.unique = unique; 487 488 vec[0].iov_base = &hdr; 489 vec[0].iov_len = sizeof(hdr); 490 vec[1].iov_base = data; 491 vec[1].iov_len = len; 492 493 res = writev(fuse->fd, vec, 2); 494 if (res < 0) { 495 ERROR("*** REPLY FAILED *** %d\n", errno); 496 } 497} 498 499void lookup_entry(struct fuse *fuse, struct node *node, 500 const char *name, __u64 unique) 501{ 502 struct fuse_entry_out out; 503 504 memset(&out, 0, sizeof(out)); 505 506 node = node_lookup(fuse, node, name, &out.attr); 507 if (!node) { 508 fuse_status(fuse, unique, -ENOENT); 509 return; 510 } 511 512 node->refcount++; 513// fprintf(stderr,"ACQUIRE %p (%s) rc=%d\n", node, node->name, node->refcount); 514 out.nodeid = node->nid; 515 out.generation = node->gen; 516 out.entry_valid = 10; 517 out.attr_valid = 10; 518 519 fuse_reply(fuse, unique, &out, sizeof(out)); 520} 521 522void handle_fuse_request(struct fuse *fuse, struct fuse_in_header *hdr, void *data, unsigned len) 523{ 524 struct node *node; 525 526 if ((len < sizeof(*hdr)) || (hdr->len != len)) { 527 ERROR("malformed header\n"); 528 return; 529 } 530 531 len -= hdr->len; 532 533 if (hdr->nodeid) { 534 node = lookup_by_inode(fuse, hdr->nodeid); 535 if (!node) { 536 fuse_status(fuse, hdr->unique, -ENOENT); 537 return; 538 } 539 } else { 540 node = 0; 541 } 542 543 switch (hdr->opcode) { 544 case FUSE_LOOKUP: { /* bytez[] -> entry_out */ 545 TRACE("LOOKUP %llx %s\n", hdr->nodeid, (char*) data); 546 lookup_entry(fuse, node, (char*) data, hdr->unique); 547 return; 548 } 549 case FUSE_FORGET: { 550 struct fuse_forget_in *req = data; 551 TRACE("FORGET %llx (%s) #%lld\n", hdr->nodeid, node->name, req->nlookup); 552 /* no reply */ 553 while (req->nlookup--) 554 node_release(node); 555 return; 556 } 557 case FUSE_GETATTR: { /* getattr_in -> attr_out */ 558 struct fuse_getattr_in *req = data; 559 struct fuse_attr_out out; 560 561 TRACE("GETATTR flags=%x fh=%llx\n", req->getattr_flags, req->fh); 562 563 memset(&out, 0, sizeof(out)); 564 node_get_attr(node, &out.attr); 565 out.attr_valid = 10; 566 567 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 568 return; 569 } 570 case FUSE_SETATTR: { /* setattr_in -> attr_out */ 571 struct fuse_setattr_in *req = data; 572 struct fuse_attr_out out; 573 char *path, buffer[PATH_BUFFER_SIZE]; 574 int res = 0; 575 struct timespec times[2]; 576 577 TRACE("SETATTR fh=%llx id=%llx valid=%x\n", 578 req->fh, hdr->nodeid, req->valid); 579 580 /* XXX: incomplete implementation on purpose. chmod/chown 581 * should NEVER be implemented.*/ 582 583 path = node_get_path(node, buffer, 0); 584 if (req->valid & FATTR_SIZE) 585 res = truncate(path, req->size); 586 if (res) 587 goto getout; 588 589 /* Handle changing atime and mtime. If FATTR_ATIME_and FATTR_ATIME_NOW 590 * are both set, then set it to the current time. Else, set it to the 591 * time specified in the request. Same goes for mtime. Use utimensat(2) 592 * as it allows ATIME and MTIME to be changed independently, and has 593 * nanosecond resolution which fuse also has. 594 */ 595 if (req->valid & (FATTR_ATIME | FATTR_MTIME)) { 596 times[0].tv_nsec = UTIME_OMIT; 597 times[1].tv_nsec = UTIME_OMIT; 598 if (req->valid & FATTR_ATIME) { 599 if (req->valid & FATTR_ATIME_NOW) { 600 times[0].tv_nsec = UTIME_NOW; 601 } else { 602 times[0].tv_sec = req->atime; 603 times[0].tv_nsec = req->atimensec; 604 } 605 } 606 if (req->valid & FATTR_MTIME) { 607 if (req->valid & FATTR_MTIME_NOW) { 608 times[1].tv_nsec = UTIME_NOW; 609 } else { 610 times[1].tv_sec = req->mtime; 611 times[1].tv_nsec = req->mtimensec; 612 } 613 } 614 TRACE("Calling utimensat on %s with atime %ld, mtime=%ld\n", path, times[0].tv_sec, times[1].tv_sec); 615 res = utimensat(-1, path, times, 0); 616 } 617 618 getout: 619 memset(&out, 0, sizeof(out)); 620 node_get_attr(node, &out.attr); 621 out.attr_valid = 10; 622 623 if (res) 624 fuse_status(fuse, hdr->unique, -errno); 625 else 626 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 627 return; 628 } 629// case FUSE_READLINK: 630// case FUSE_SYMLINK: 631 case FUSE_MKNOD: { /* mknod_in, bytez[] -> entry_out */ 632 struct fuse_mknod_in *req = data; 633 char *path, buffer[PATH_BUFFER_SIZE]; 634 char *name = ((char*) data) + sizeof(*req); 635 int res; 636 637 TRACE("MKNOD %s @ %llx\n", name, hdr->nodeid); 638 path = node_get_path(node, buffer, name); 639 640 req->mode = (req->mode & (~0777)) | 0664; 641 res = mknod(path, req->mode, req->rdev); /* XXX perm?*/ 642 if (res < 0) { 643 fuse_status(fuse, hdr->unique, -errno); 644 } else { 645 lookup_entry(fuse, node, name, hdr->unique); 646 } 647 return; 648 } 649 case FUSE_MKDIR: { /* mkdir_in, bytez[] -> entry_out */ 650 struct fuse_mkdir_in *req = data; 651 struct fuse_entry_out out; 652 char *path, buffer[PATH_BUFFER_SIZE]; 653 char *name = ((char*) data) + sizeof(*req); 654 int res; 655 656 TRACE("MKDIR %s @ %llx 0%o\n", name, hdr->nodeid, req->mode); 657 path = node_get_path(node, buffer, name); 658 659 req->mode = (req->mode & (~0777)) | 0775; 660 res = mkdir(path, req->mode); 661 if (res < 0) { 662 fuse_status(fuse, hdr->unique, -errno); 663 } else { 664 lookup_entry(fuse, node, name, hdr->unique); 665 } 666 return; 667 } 668 case FUSE_UNLINK: { /* bytez[] -> */ 669 char *path, buffer[PATH_BUFFER_SIZE]; 670 int res; 671 TRACE("UNLINK %s @ %llx\n", (char*) data, hdr->nodeid); 672 path = node_get_path(node, buffer, (char*) data); 673 res = unlink(path); 674 fuse_status(fuse, hdr->unique, res ? -errno : 0); 675 return; 676 } 677 case FUSE_RMDIR: { /* bytez[] -> */ 678 char *path, buffer[PATH_BUFFER_SIZE]; 679 int res; 680 TRACE("RMDIR %s @ %llx\n", (char*) data, hdr->nodeid); 681 path = node_get_path(node, buffer, (char*) data); 682 res = rmdir(path); 683 fuse_status(fuse, hdr->unique, res ? -errno : 0); 684 return; 685 } 686 case FUSE_RENAME: { /* rename_in, oldname, newname -> */ 687 struct fuse_rename_in *req = data; 688 char *oldname = ((char*) data) + sizeof(*req); 689 char *newname = oldname + strlen(oldname) + 1; 690 char *oldpath, oldbuffer[PATH_BUFFER_SIZE]; 691 char *newpath, newbuffer[PATH_BUFFER_SIZE]; 692 struct node *target; 693 struct node *newparent; 694 int res; 695 696 TRACE("RENAME %s->%s @ %llx\n", oldname, newname, hdr->nodeid); 697 698 target = lookup_child_by_name(node, oldname); 699 if (!target) { 700 fuse_status(fuse, hdr->unique, -ENOENT); 701 return; 702 } 703 oldpath = node_get_path(node, oldbuffer, oldname); 704 705 newparent = lookup_by_inode(fuse, req->newdir); 706 if (!newparent) { 707 fuse_status(fuse, hdr->unique, -ENOENT); 708 return; 709 } 710 if (newparent == node) { 711 /* Special case for renaming a file where destination 712 * is same path differing only by case. 713 * In this case we don't want to look for a case insensitive match. 714 * This allows commands like "mv foo FOO" to work as expected. 715 */ 716 newpath = do_node_get_path(newparent, newbuffer, newname, NO_CASE_SENSITIVE_MATCH); 717 } else { 718 newpath = node_get_path(newparent, newbuffer, newname); 719 } 720 721 if (!remove_child(node, target->nid)) { 722 ERROR("RENAME remove_child not found"); 723 fuse_status(fuse, hdr->unique, -ENOENT); 724 return; 725 } 726 if (!rename_node(target, newname)) { 727 fuse_status(fuse, hdr->unique, -ENOMEM); 728 return; 729 } 730 add_node_to_parent(target, newparent); 731 732 res = rename(oldpath, newpath); 733 TRACE("RENAME result %d\n", res); 734 735 fuse_status(fuse, hdr->unique, res ? -errno : 0); 736 return; 737 } 738// case FUSE_LINK: 739 case FUSE_OPEN: { /* open_in -> open_out */ 740 struct fuse_open_in *req = data; 741 struct fuse_open_out out; 742 char *path, buffer[PATH_BUFFER_SIZE]; 743 struct handle *h; 744 745 h = malloc(sizeof(*h)); 746 if (!h) { 747 fuse_status(fuse, hdr->unique, -ENOMEM); 748 return; 749 } 750 751 path = node_get_path(node, buffer, 0); 752 TRACE("OPEN %llx '%s' 0%o fh=%p\n", hdr->nodeid, path, req->flags, h); 753 h->fd = open(path, req->flags); 754 if (h->fd < 0) { 755 ERROR("ERROR\n"); 756 fuse_status(fuse, hdr->unique, -errno); 757 free(h); 758 return; 759 } 760 out.fh = ptr_to_id(h); 761 out.open_flags = 0; 762 out.padding = 0; 763 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 764 return; 765 } 766 case FUSE_READ: { /* read_in -> byte[] */ 767 char buffer[128 * 1024]; 768 struct fuse_read_in *req = data; 769 struct handle *h = id_to_ptr(req->fh); 770 int res; 771 TRACE("READ %p(%d) %u@%llu\n", h, h->fd, req->size, req->offset); 772 if (req->size > sizeof(buffer)) { 773 fuse_status(fuse, hdr->unique, -EINVAL); 774 return; 775 } 776 res = pread64(h->fd, buffer, req->size, req->offset); 777 if (res < 0) { 778 fuse_status(fuse, hdr->unique, -errno); 779 return; 780 } 781 fuse_reply(fuse, hdr->unique, buffer, res); 782 return; 783 } 784 case FUSE_WRITE: { /* write_in, byte[write_in.size] -> write_out */ 785 struct fuse_write_in *req = data; 786 struct fuse_write_out out; 787 struct handle *h = id_to_ptr(req->fh); 788 int res; 789 TRACE("WRITE %p(%d) %u@%llu\n", h, h->fd, req->size, req->offset); 790 res = pwrite64(h->fd, ((char*) data) + sizeof(*req), req->size, req->offset); 791 if (res < 0) { 792 fuse_status(fuse, hdr->unique, -errno); 793 return; 794 } 795 out.size = res; 796 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 797 goto oops; 798 } 799 case FUSE_STATFS: { /* getattr_in -> attr_out */ 800 struct statfs stat; 801 struct fuse_statfs_out out; 802 int res; 803 804 TRACE("STATFS\n"); 805 806 if (statfs(fuse->root.name, &stat)) { 807 fuse_status(fuse, hdr->unique, -errno); 808 return; 809 } 810 811 memset(&out, 0, sizeof(out)); 812 out.st.blocks = stat.f_blocks; 813 out.st.bfree = stat.f_bfree; 814 out.st.bavail = stat.f_bavail; 815 out.st.files = stat.f_files; 816 out.st.ffree = stat.f_ffree; 817 out.st.bsize = stat.f_bsize; 818 out.st.namelen = stat.f_namelen; 819 out.st.frsize = stat.f_frsize; 820 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 821 return; 822 } 823 case FUSE_RELEASE: { /* release_in -> */ 824 struct fuse_release_in *req = data; 825 struct handle *h = id_to_ptr(req->fh); 826 TRACE("RELEASE %p(%d)\n", h, h->fd); 827 close(h->fd); 828 free(h); 829 fuse_status(fuse, hdr->unique, 0); 830 return; 831 } 832// case FUSE_FSYNC: 833// case FUSE_SETXATTR: 834// case FUSE_GETXATTR: 835// case FUSE_LISTXATTR: 836// case FUSE_REMOVEXATTR: 837 case FUSE_FLUSH: 838 fuse_status(fuse, hdr->unique, 0); 839 return; 840 case FUSE_OPENDIR: { /* open_in -> open_out */ 841 struct fuse_open_in *req = data; 842 struct fuse_open_out out; 843 char *path, buffer[PATH_BUFFER_SIZE]; 844 struct dirhandle *h; 845 846 h = malloc(sizeof(*h)); 847 if (!h) { 848 fuse_status(fuse, hdr->unique, -ENOMEM); 849 return; 850 } 851 852 path = node_get_path(node, buffer, 0); 853 TRACE("OPENDIR %llx '%s'\n", hdr->nodeid, path); 854 h->d = opendir(path); 855 if (h->d == 0) { 856 ERROR("ERROR\n"); 857 fuse_status(fuse, hdr->unique, -errno); 858 free(h); 859 return; 860 } 861 out.fh = ptr_to_id(h); 862 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 863 return; 864 } 865 case FUSE_READDIR: { 866 struct fuse_read_in *req = data; 867 char buffer[8192]; 868 struct fuse_dirent *fde = (struct fuse_dirent*) buffer; 869 struct dirent *de; 870 struct dirhandle *h = id_to_ptr(req->fh); 871 TRACE("READDIR %p\n", h); 872 if (req->offset == 0) { 873 /* rewinddir() might have been called above us, so rewind here too */ 874 TRACE("calling rewinddir()\n"); 875 rewinddir(h->d); 876 } 877 de = readdir(h->d); 878 if (!de) { 879 fuse_status(fuse, hdr->unique, 0); 880 return; 881 } 882 fde->ino = FUSE_UNKNOWN_INO; 883 /* increment the offset so we can detect when rewinddir() seeks back to the beginning */ 884 fde->off = req->offset + 1; 885 fde->type = de->d_type; 886 fde->namelen = strlen(de->d_name); 887 memcpy(fde->name, de->d_name, fde->namelen + 1); 888 fuse_reply(fuse, hdr->unique, fde, 889 FUSE_DIRENT_ALIGN(sizeof(struct fuse_dirent) + fde->namelen)); 890 return; 891 } 892 case FUSE_RELEASEDIR: { /* release_in -> */ 893 struct fuse_release_in *req = data; 894 struct dirhandle *h = id_to_ptr(req->fh); 895 TRACE("RELEASEDIR %p\n",h); 896 closedir(h->d); 897 free(h); 898 fuse_status(fuse, hdr->unique, 0); 899 return; 900 } 901// case FUSE_FSYNCDIR: 902 case FUSE_INIT: { /* init_in -> init_out */ 903 struct fuse_init_in *req = data; 904 struct fuse_init_out out; 905 906 TRACE("INIT ver=%d.%d maxread=%d flags=%x\n", 907 req->major, req->minor, req->max_readahead, req->flags); 908 909 out.major = FUSE_KERNEL_VERSION; 910 out.minor = FUSE_KERNEL_MINOR_VERSION; 911 out.max_readahead = req->max_readahead; 912 out.flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES; 913 out.max_background = 32; 914 out.congestion_threshold = 32; 915 out.max_write = 256 * 1024; 916 917 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 918 return; 919 } 920 default: { 921 struct fuse_out_header h; 922 ERROR("NOTIMPL op=%d uniq=%llx nid=%llx\n", 923 hdr->opcode, hdr->unique, hdr->nodeid); 924 925 oops: 926 h.len = sizeof(h); 927 h.error = -ENOSYS; 928 h.unique = hdr->unique; 929 write(fuse->fd, &h, sizeof(h)); 930 break; 931 } 932 } 933} 934 935void handle_fuse_requests(struct fuse *fuse) 936{ 937 unsigned char req[256 * 1024 + 128]; 938 int len; 939 940 for (;;) { 941 len = read(fuse->fd, req, sizeof(req)); 942 if (len < 0) { 943 if (errno == EINTR) 944 continue; 945 ERROR("handle_fuse_requests: errno=%d\n", errno); 946 return; 947 } 948 handle_fuse_request(fuse, (void*) req, (void*) (req + sizeof(struct fuse_in_header)), len); 949 } 950} 951 952static int usage() 953{ 954 ERROR("usage: sdcard <path> <uid> <gid>\n"); 955 return -1; 956} 957 958int main(int argc, char **argv) 959{ 960 struct fuse fuse; 961 char opts[256]; 962 int fd; 963 int res; 964 const char *path = NULL; 965 int i; 966 unsigned int uid = 0; 967 unsigned int gid = 0; 968 969 970 if (argc != 4) { 971 return usage(); 972 } 973 974 path = argv[1]; 975 976 char* endptr = NULL; 977 errno = 0; 978 uid = strtoul(argv[2], &endptr, 10); 979 if (*endptr != '\0' || errno != 0) { 980 ERROR("Invalid uid"); 981 return usage(); 982 } 983 984 endptr = NULL; 985 errno = 0; 986 gid = strtoul(argv[3], &endptr, 10); 987 if (*endptr != '\0' || errno != 0) { 988 ERROR("Invalid gid"); 989 return usage(); 990 } 991 992 /* cleanup from previous instance, if necessary */ 993 umount2(MOUNT_POINT, 2); 994 995 fd = open("/dev/fuse", O_RDWR); 996 if (fd < 0){ 997 ERROR("cannot open fuse device (%d)\n", errno); 998 return -1; 999 } 1000 1001 sprintf(opts, "fd=%i,rootmode=40000,default_permissions,allow_other," 1002 "user_id=%d,group_id=%d", fd, uid, gid); 1003 1004 res = mount("/dev/fuse", MOUNT_POINT, "fuse", MS_NOSUID | MS_NODEV, opts); 1005 if (res < 0) { 1006 ERROR("cannot mount fuse filesystem (%d)\n", errno); 1007 return -1; 1008 } 1009 1010 if (setgid(gid) < 0) { 1011 ERROR("cannot setgid!\n"); 1012 return -1; 1013 } 1014 if (setuid(uid) < 0) { 1015 ERROR("cannot setuid!\n"); 1016 return -1; 1017 } 1018 1019 fuse_init(&fuse, fd, path); 1020 1021 umask(0); 1022 handle_fuse_requests(&fuse); 1023 1024 return 0; 1025} 1026