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 75 struct handle { 76 struct node *node; 77 int fd; 78 }; 79 80 struct dirhandle { 81 struct node *node; 82 DIR *d; 83 }; 84 85 struct 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 }; 105 106 struct 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 static unsigned uid = -1; 119 static unsigned gid = -1; 120 121 #define PATH_BUFFER_SIZE 1024 122 123 #define NO_CASE_SENSITIVE_MATCH 0 124 #define CASE_SENSITIVE_MATCH 1 125 126 /* 127 * Get the real-life absolute path to a node. 128 * node: start at this node 129 * buf: storage for returned string 130 * name: append this string to path if set 131 */ 132 char *do_node_get_path(struct node *node, char *buf, const char *name, int match_case_insensitive) 133 { 134 struct node *in_node = node; 135 const char *in_name = name; 136 char *out = buf + PATH_BUFFER_SIZE - 1; 137 int len; 138 out[0] = 0; 139 140 if (name) { 141 len = strlen(name); 142 goto start; 143 } 144 145 while (node) { 146 name = (node->actual_name ? node->actual_name : node->name); 147 len = node->namelen; 148 node = node->parent; 149 start: 150 if ((len + 1) > (out - buf)) 151 return 0; 152 out -= len; 153 memcpy(out, name, len); 154 /* avoid double slash at beginning of path */ 155 if (out[0] != '/') { 156 out --; 157 out[0] = '/'; 158 } 159 } 160 161 /* If we are searching for a file within node (rather than computing node's path) 162 * and fail, then we need to look for a case insensitive match. 163 */ 164 if (in_name && match_case_insensitive && access(out, F_OK) != 0) { 165 char *path, buffer[PATH_BUFFER_SIZE]; 166 DIR* dir; 167 struct dirent* entry; 168 path = do_node_get_path(in_node, buffer, NULL, NO_CASE_SENSITIVE_MATCH); 169 dir = opendir(path); 170 if (!dir) { 171 ERROR("opendir %s failed: %s", path, strerror(errno)); 172 return out; 173 } 174 175 while ((entry = readdir(dir))) { 176 if (!strcasecmp(entry->d_name, in_name)) { 177 /* we have a match - replace the name */ 178 len = strlen(in_name); 179 memcpy(buf + PATH_BUFFER_SIZE - len - 1, entry->d_name, len); 180 break; 181 } 182 } 183 closedir(dir); 184 } 185 186 return out; 187 } 188 189 char *node_get_path(struct node *node, char *buf, const char *name) 190 { 191 /* We look for case insensitive matches by default */ 192 return do_node_get_path(node, buf, name, CASE_SENSITIVE_MATCH); 193 } 194 195 void attr_from_stat(struct fuse_attr *attr, struct stat *s) 196 { 197 attr->ino = s->st_ino; 198 attr->size = s->st_size; 199 attr->blocks = s->st_blocks; 200 attr->atime = s->st_atime; 201 attr->mtime = s->st_mtime; 202 attr->ctime = s->st_ctime; 203 attr->atimensec = s->st_atime_nsec; 204 attr->mtimensec = s->st_mtime_nsec; 205 attr->ctimensec = s->st_ctime_nsec; 206 attr->mode = s->st_mode; 207 attr->nlink = s->st_nlink; 208 209 /* force permissions to something reasonable: 210 * world readable 211 * writable by the sdcard group 212 */ 213 if (attr->mode & 0100) { 214 attr->mode = (attr->mode & (~0777)) | 0775; 215 } else { 216 attr->mode = (attr->mode & (~0777)) | 0664; 217 } 218 219 /* all files owned by root.sdcard */ 220 attr->uid = 0; 221 attr->gid = AID_SDCARD_RW; 222 } 223 224 int node_get_attr(struct node *node, struct fuse_attr *attr) 225 { 226 int res; 227 struct stat s; 228 char *path, buffer[PATH_BUFFER_SIZE]; 229 230 path = node_get_path(node, buffer, 0); 231 res = lstat(path, &s); 232 if (res < 0) { 233 ERROR("lstat('%s') errno %d\n", path, errno); 234 return -1; 235 } 236 237 attr_from_stat(attr, &s); 238 attr->ino = node->nid; 239 240 return 0; 241 } 242 243 static void add_node_to_parent(struct node *node, struct node *parent) { 244 node->parent = parent; 245 node->next = parent->child; 246 parent->child = node; 247 parent->refcount++; 248 } 249 250 /* Check to see if our parent directory already has a file with a name 251 * that differs only by case. If we find one, store it in the actual_name 252 * field so node_get_path will map it to this file in the underlying storage. 253 */ 254 static void node_find_actual_name(struct node *node) 255 { 256 char *path, buffer[PATH_BUFFER_SIZE]; 257 const char *node_name = node->name; 258 DIR* dir; 259 struct dirent* entry; 260 261 if (!node->parent) return; 262 263 path = node_get_path(node->parent, buffer, 0); 264 dir = opendir(path); 265 if (!dir) { 266 ERROR("opendir %s failed: %s", path, strerror(errno)); 267 return; 268 } 269 270 while ((entry = readdir(dir))) { 271 const char *test_name = entry->d_name; 272 if (strcmp(test_name, node_name) && !strcasecmp(test_name, node_name)) { 273 /* we have a match - differs but only by case */ 274 node->actual_name = strdup(test_name); 275 if (!node->actual_name) { 276 ERROR("strdup failed - out of memory\n"); 277 exit(1); 278 } 279 break; 280 } 281 } 282 closedir(dir); 283 } 284 285 struct node *node_create(struct node *parent, const char *name, __u64 nid, __u64 gen) 286 { 287 struct node *node; 288 int namelen = strlen(name); 289 290 node = calloc(1, sizeof(struct node)); 291 if (node == 0) { 292 return 0; 293 } 294 node->name = malloc(namelen + 1); 295 if (node->name == 0) { 296 free(node); 297 return 0; 298 } 299 300 node->nid = nid; 301 node->gen = gen; 302 add_node_to_parent(node, parent); 303 memcpy(node->name, name, namelen + 1); 304 node->namelen = namelen; 305 node_find_actual_name(node); 306 return node; 307 } 308 309 static char *rename_node(struct node *node, const char *name) 310 { 311 node->namelen = strlen(name); 312 char *newname = realloc(node->name, node->namelen + 1); 313 if (newname == 0) 314 return 0; 315 node->name = newname; 316 memcpy(node->name, name, node->namelen + 1); 317 node_find_actual_name(node); 318 return node->name; 319 } 320 321 void fuse_init(struct fuse *fuse, int fd, const char *path) 322 { 323 fuse->fd = fd; 324 fuse->next_node_id = 2; 325 fuse->next_generation = 0; 326 327 fuse->all = &fuse->root; 328 329 memset(&fuse->root, 0, sizeof(fuse->root)); 330 fuse->root.nid = FUSE_ROOT_ID; /* 1 */ 331 fuse->root.refcount = 2; 332 rename_node(&fuse->root, path); 333 } 334 335 static inline void *id_to_ptr(__u64 nid) 336 { 337 return (void *) nid; 338 } 339 340 static inline __u64 ptr_to_id(void *ptr) 341 { 342 return (__u64) ptr; 343 } 344 345 346 struct node *lookup_by_inode(struct fuse *fuse, __u64 nid) 347 { 348 if (nid == FUSE_ROOT_ID) { 349 return &fuse->root; 350 } else { 351 return id_to_ptr(nid); 352 } 353 } 354 355 struct node *lookup_child_by_name(struct node *node, const char *name) 356 { 357 for (node = node->child; node; node = node->next) { 358 if (!strcmp(name, node->name)) { 359 return node; 360 } 361 } 362 return 0; 363 } 364 365 struct node *lookup_child_by_inode(struct node *node, __u64 nid) 366 { 367 for (node = node->child; node; node = node->next) { 368 if (node->nid == nid) { 369 return node; 370 } 371 } 372 return 0; 373 } 374 375 static void dec_refcount(struct node *node) { 376 if (node->refcount > 0) { 377 node->refcount--; 378 TRACE("dec_refcount %p(%s) -> %d\n", node, node->name, node->refcount); 379 } else { 380 ERROR("Zero refcnt %p\n", node); 381 } 382 } 383 384 static struct node *remove_child(struct node *parent, __u64 nid) 385 { 386 struct node *prev = 0; 387 struct node *node; 388 389 for (node = parent->child; node; node = node->next) { 390 if (node->nid == nid) { 391 if (prev) { 392 prev->next = node->next; 393 } else { 394 parent->child = node->next; 395 } 396 node->next = 0; 397 node->parent = 0; 398 dec_refcount(parent); 399 return node; 400 } 401 prev = node; 402 } 403 return 0; 404 } 405 406 struct node *node_lookup(struct fuse *fuse, struct node *parent, const char *name, 407 struct fuse_attr *attr) 408 { 409 int res; 410 struct stat s; 411 char *path, buffer[PATH_BUFFER_SIZE]; 412 struct node *node; 413 414 path = node_get_path(parent, buffer, name); 415 /* XXX error? */ 416 417 res = lstat(path, &s); 418 if (res < 0) 419 return 0; 420 421 node = lookup_child_by_name(parent, name); 422 if (!node) { 423 node = node_create(parent, name, fuse->next_node_id++, fuse->next_generation++); 424 if (!node) 425 return 0; 426 node->nid = ptr_to_id(node); 427 node->all = fuse->all; 428 fuse->all = node; 429 } 430 431 attr_from_stat(attr, &s); 432 attr->ino = node->nid; 433 434 return node; 435 } 436 437 void node_release(struct node *node) 438 { 439 TRACE("RELEASE %p (%s) rc=%d\n", node, node->name, node->refcount); 440 dec_refcount(node); 441 if (node->refcount == 0) { 442 if (node->parent->child == node) { 443 node->parent->child = node->parent->child->next; 444 } else { 445 struct node *node2; 446 447 node2 = node->parent->child; 448 while (node2->next != node) 449 node2 = node2->next; 450 node2->next = node->next; 451 } 452 453 TRACE("DESTROY %p (%s)\n", node, node->name); 454 455 node_release(node->parent); 456 457 node->parent = 0; 458 node->next = 0; 459 460 /* TODO: remove debugging - poison memory */ 461 memset(node->name, 0xef, node->namelen); 462 free(node->name); 463 free(node->actual_name); 464 memset(node, 0xfc, sizeof(*node)); 465 free(node); 466 } 467 } 468 469 void fuse_status(struct fuse *fuse, __u64 unique, int err) 470 { 471 struct fuse_out_header hdr; 472 hdr.len = sizeof(hdr); 473 hdr.error = err; 474 hdr.unique = unique; 475 if (err) { 476 // ERROR("*** %d ***\n", err); 477 } 478 write(fuse->fd, &hdr, sizeof(hdr)); 479 } 480 481 void fuse_reply(struct fuse *fuse, __u64 unique, void *data, int len) 482 { 483 struct fuse_out_header hdr; 484 struct iovec vec[2]; 485 int res; 486 487 hdr.len = len + sizeof(hdr); 488 hdr.error = 0; 489 hdr.unique = unique; 490 491 vec[0].iov_base = &hdr; 492 vec[0].iov_len = sizeof(hdr); 493 vec[1].iov_base = data; 494 vec[1].iov_len = len; 495 496 res = writev(fuse->fd, vec, 2); 497 if (res < 0) { 498 ERROR("*** REPLY FAILED *** %d\n", errno); 499 } 500 } 501 502 void lookup_entry(struct fuse *fuse, struct node *node, 503 const char *name, __u64 unique) 504 { 505 struct fuse_entry_out out; 506 507 memset(&out, 0, sizeof(out)); 508 509 node = node_lookup(fuse, node, name, &out.attr); 510 if (!node) { 511 fuse_status(fuse, unique, -ENOENT); 512 return; 513 } 514 515 node->refcount++; 516 // fprintf(stderr,"ACQUIRE %p (%s) rc=%d\n", node, node->name, node->refcount); 517 out.nodeid = node->nid; 518 out.generation = node->gen; 519 out.entry_valid = 10; 520 out.attr_valid = 10; 521 522 fuse_reply(fuse, unique, &out, sizeof(out)); 523 } 524 525 void handle_fuse_request(struct fuse *fuse, struct fuse_in_header *hdr, void *data, unsigned len) 526 { 527 struct node *node; 528 529 if ((len < sizeof(*hdr)) || (hdr->len != len)) { 530 ERROR("malformed header\n"); 531 return; 532 } 533 534 len -= hdr->len; 535 536 if (hdr->nodeid) { 537 node = lookup_by_inode(fuse, hdr->nodeid); 538 if (!node) { 539 fuse_status(fuse, hdr->unique, -ENOENT); 540 return; 541 } 542 } else { 543 node = 0; 544 } 545 546 switch (hdr->opcode) { 547 case FUSE_LOOKUP: { /* bytez[] -> entry_out */ 548 TRACE("LOOKUP %llx %s\n", hdr->nodeid, (char*) data); 549 lookup_entry(fuse, node, (char*) data, hdr->unique); 550 return; 551 } 552 case FUSE_FORGET: { 553 struct fuse_forget_in *req = data; 554 TRACE("FORGET %llx (%s) #%lld\n", hdr->nodeid, node->name, req->nlookup); 555 /* no reply */ 556 while (req->nlookup--) 557 node_release(node); 558 return; 559 } 560 case FUSE_GETATTR: { /* getattr_in -> attr_out */ 561 struct fuse_getattr_in *req = data; 562 struct fuse_attr_out out; 563 564 TRACE("GETATTR flags=%x fh=%llx\n", req->getattr_flags, req->fh); 565 566 memset(&out, 0, sizeof(out)); 567 node_get_attr(node, &out.attr); 568 out.attr_valid = 10; 569 570 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 571 return; 572 } 573 case FUSE_SETATTR: { /* setattr_in -> attr_out */ 574 struct fuse_setattr_in *req = data; 575 struct fuse_attr_out out; 576 char *path, buffer[PATH_BUFFER_SIZE]; 577 int res = 0; 578 struct timespec times[2]; 579 580 TRACE("SETATTR fh=%llx id=%llx valid=%x\n", 581 req->fh, hdr->nodeid, req->valid); 582 583 /* XXX: incomplete implementation on purpose. chmod/chown 584 * should NEVER be implemented.*/ 585 586 path = node_get_path(node, buffer, 0); 587 if (req->valid & FATTR_SIZE) 588 res = truncate(path, req->size); 589 if (res) 590 goto getout; 591 592 /* Handle changing atime and mtime. If FATTR_ATIME_and FATTR_ATIME_NOW 593 * are both set, then set it to the current time. Else, set it to the 594 * time specified in the request. Same goes for mtime. Use utimensat(2) 595 * as it allows ATIME and MTIME to be changed independently, and has 596 * nanosecond resolution which fuse also has. 597 */ 598 if (req->valid & (FATTR_ATIME | FATTR_MTIME)) { 599 times[0].tv_nsec = UTIME_OMIT; 600 times[1].tv_nsec = UTIME_OMIT; 601 if (req->valid & FATTR_ATIME) { 602 if (req->valid & FATTR_ATIME_NOW) { 603 times[0].tv_nsec = UTIME_NOW; 604 } else { 605 times[0].tv_sec = req->atime; 606 times[0].tv_nsec = req->atimensec; 607 } 608 } 609 if (req->valid & FATTR_MTIME) { 610 if (req->valid & FATTR_MTIME_NOW) { 611 times[1].tv_nsec = UTIME_NOW; 612 } else { 613 times[1].tv_sec = req->mtime; 614 times[1].tv_nsec = req->mtimensec; 615 } 616 } 617 TRACE("Calling utimensat on %s with atime %ld, mtime=%ld\n", path, times[0].tv_sec, times[1].tv_sec); 618 res = utimensat(-1, path, times, 0); 619 } 620 621 getout: 622 memset(&out, 0, sizeof(out)); 623 node_get_attr(node, &out.attr); 624 out.attr_valid = 10; 625 626 if (res) 627 fuse_status(fuse, hdr->unique, -errno); 628 else 629 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 630 return; 631 } 632 // case FUSE_READLINK: 633 // case FUSE_SYMLINK: 634 case FUSE_MKNOD: { /* mknod_in, bytez[] -> entry_out */ 635 struct fuse_mknod_in *req = data; 636 char *path, buffer[PATH_BUFFER_SIZE]; 637 char *name = ((char*) data) + sizeof(*req); 638 int res; 639 640 TRACE("MKNOD %s @ %llx\n", name, hdr->nodeid); 641 path = node_get_path(node, buffer, name); 642 643 req->mode = (req->mode & (~0777)) | 0664; 644 res = mknod(path, req->mode, req->rdev); /* XXX perm?*/ 645 if (res < 0) { 646 fuse_status(fuse, hdr->unique, -errno); 647 } else { 648 lookup_entry(fuse, node, name, hdr->unique); 649 } 650 return; 651 } 652 case FUSE_MKDIR: { /* mkdir_in, bytez[] -> entry_out */ 653 struct fuse_mkdir_in *req = data; 654 struct fuse_entry_out out; 655 char *path, buffer[PATH_BUFFER_SIZE]; 656 char *name = ((char*) data) + sizeof(*req); 657 int res; 658 659 TRACE("MKDIR %s @ %llx 0%o\n", name, hdr->nodeid, req->mode); 660 path = node_get_path(node, buffer, name); 661 662 req->mode = (req->mode & (~0777)) | 0775; 663 res = mkdir(path, req->mode); 664 if (res < 0) { 665 fuse_status(fuse, hdr->unique, -errno); 666 } else { 667 lookup_entry(fuse, node, name, hdr->unique); 668 } 669 return; 670 } 671 case FUSE_UNLINK: { /* bytez[] -> */ 672 char *path, buffer[PATH_BUFFER_SIZE]; 673 int res; 674 TRACE("UNLINK %s @ %llx\n", (char*) data, hdr->nodeid); 675 path = node_get_path(node, buffer, (char*) data); 676 res = unlink(path); 677 fuse_status(fuse, hdr->unique, res ? -errno : 0); 678 return; 679 } 680 case FUSE_RMDIR: { /* bytez[] -> */ 681 char *path, buffer[PATH_BUFFER_SIZE]; 682 int res; 683 TRACE("RMDIR %s @ %llx\n", (char*) data, hdr->nodeid); 684 path = node_get_path(node, buffer, (char*) data); 685 res = rmdir(path); 686 fuse_status(fuse, hdr->unique, res ? -errno : 0); 687 return; 688 } 689 case FUSE_RENAME: { /* rename_in, oldname, newname -> */ 690 struct fuse_rename_in *req = data; 691 char *oldname = ((char*) data) + sizeof(*req); 692 char *newname = oldname + strlen(oldname) + 1; 693 char *oldpath, oldbuffer[PATH_BUFFER_SIZE]; 694 char *newpath, newbuffer[PATH_BUFFER_SIZE]; 695 struct node *target; 696 struct node *newparent; 697 int res; 698 699 TRACE("RENAME %s->%s @ %llx\n", oldname, newname, hdr->nodeid); 700 701 target = lookup_child_by_name(node, oldname); 702 if (!target) { 703 fuse_status(fuse, hdr->unique, -ENOENT); 704 return; 705 } 706 oldpath = node_get_path(node, oldbuffer, oldname); 707 708 newparent = lookup_by_inode(fuse, req->newdir); 709 if (!newparent) { 710 fuse_status(fuse, hdr->unique, -ENOENT); 711 return; 712 } 713 if (newparent == node) { 714 /* Special case for renaming a file where destination 715 * is same path differing only by case. 716 * In this case we don't want to look for a case insensitive match. 717 * This allows commands like "mv foo FOO" to work as expected. 718 */ 719 newpath = do_node_get_path(newparent, newbuffer, newname, NO_CASE_SENSITIVE_MATCH); 720 } else { 721 newpath = node_get_path(newparent, newbuffer, newname); 722 } 723 724 if (!remove_child(node, target->nid)) { 725 ERROR("RENAME remove_child not found"); 726 fuse_status(fuse, hdr->unique, -ENOENT); 727 return; 728 } 729 if (!rename_node(target, newname)) { 730 fuse_status(fuse, hdr->unique, -ENOMEM); 731 return; 732 } 733 add_node_to_parent(target, newparent); 734 735 res = rename(oldpath, newpath); 736 TRACE("RENAME result %d\n", res); 737 738 fuse_status(fuse, hdr->unique, res ? -errno : 0); 739 return; 740 } 741 // case FUSE_LINK: 742 case FUSE_OPEN: { /* open_in -> open_out */ 743 struct fuse_open_in *req = data; 744 struct fuse_open_out out; 745 char *path, buffer[PATH_BUFFER_SIZE]; 746 struct handle *h; 747 748 h = malloc(sizeof(*h)); 749 if (!h) { 750 fuse_status(fuse, hdr->unique, -ENOMEM); 751 return; 752 } 753 754 path = node_get_path(node, buffer, 0); 755 TRACE("OPEN %llx '%s' 0%o fh=%p\n", hdr->nodeid, path, req->flags, h); 756 h->fd = open(path, req->flags); 757 if (h->fd < 0) { 758 ERROR("ERROR\n"); 759 fuse_status(fuse, hdr->unique, -errno); 760 free(h); 761 return; 762 } 763 out.fh = ptr_to_id(h); 764 out.open_flags = 0; 765 out.padding = 0; 766 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 767 return; 768 } 769 case FUSE_READ: { /* read_in -> byte[] */ 770 char buffer[128 * 1024]; 771 struct fuse_read_in *req = data; 772 struct handle *h = id_to_ptr(req->fh); 773 int res; 774 TRACE("READ %p(%d) %u@%llu\n", h, h->fd, req->size, req->offset); 775 if (req->size > sizeof(buffer)) { 776 fuse_status(fuse, hdr->unique, -EINVAL); 777 return; 778 } 779 res = pread64(h->fd, buffer, req->size, req->offset); 780 if (res < 0) { 781 fuse_status(fuse, hdr->unique, -errno); 782 return; 783 } 784 fuse_reply(fuse, hdr->unique, buffer, res); 785 return; 786 } 787 case FUSE_WRITE: { /* write_in, byte[write_in.size] -> write_out */ 788 struct fuse_write_in *req = data; 789 struct fuse_write_out out; 790 struct handle *h = id_to_ptr(req->fh); 791 int res; 792 TRACE("WRITE %p(%d) %u@%llu\n", h, h->fd, req->size, req->offset); 793 res = pwrite64(h->fd, ((char*) data) + sizeof(*req), req->size, req->offset); 794 if (res < 0) { 795 fuse_status(fuse, hdr->unique, -errno); 796 return; 797 } 798 out.size = res; 799 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 800 goto oops; 801 } 802 case FUSE_STATFS: { /* getattr_in -> attr_out */ 803 struct statfs stat; 804 struct fuse_statfs_out out; 805 int res; 806 807 TRACE("STATFS\n"); 808 809 if (statfs(fuse->root.name, &stat)) { 810 fuse_status(fuse, hdr->unique, -errno); 811 return; 812 } 813 814 memset(&out, 0, sizeof(out)); 815 out.st.blocks = stat.f_blocks; 816 out.st.bfree = stat.f_bfree; 817 out.st.bavail = stat.f_bavail; 818 out.st.files = stat.f_files; 819 out.st.ffree = stat.f_ffree; 820 out.st.bsize = stat.f_bsize; 821 out.st.namelen = stat.f_namelen; 822 out.st.frsize = stat.f_frsize; 823 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 824 return; 825 } 826 case FUSE_RELEASE: { /* release_in -> */ 827 struct fuse_release_in *req = data; 828 struct handle *h = id_to_ptr(req->fh); 829 TRACE("RELEASE %p(%d)\n", h, h->fd); 830 close(h->fd); 831 free(h); 832 fuse_status(fuse, hdr->unique, 0); 833 return; 834 } 835 // case FUSE_FSYNC: 836 // case FUSE_SETXATTR: 837 // case FUSE_GETXATTR: 838 // case FUSE_LISTXATTR: 839 // case FUSE_REMOVEXATTR: 840 case FUSE_FLUSH: 841 fuse_status(fuse, hdr->unique, 0); 842 return; 843 case FUSE_OPENDIR: { /* open_in -> open_out */ 844 struct fuse_open_in *req = data; 845 struct fuse_open_out out; 846 char *path, buffer[PATH_BUFFER_SIZE]; 847 struct dirhandle *h; 848 849 h = malloc(sizeof(*h)); 850 if (!h) { 851 fuse_status(fuse, hdr->unique, -ENOMEM); 852 return; 853 } 854 855 path = node_get_path(node, buffer, 0); 856 TRACE("OPENDIR %llx '%s'\n", hdr->nodeid, path); 857 h->d = opendir(path); 858 if (h->d == 0) { 859 ERROR("ERROR\n"); 860 fuse_status(fuse, hdr->unique, -errno); 861 free(h); 862 return; 863 } 864 out.fh = ptr_to_id(h); 865 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 866 return; 867 } 868 case FUSE_READDIR: { 869 struct fuse_read_in *req = data; 870 char buffer[8192]; 871 struct fuse_dirent *fde = (struct fuse_dirent*) buffer; 872 struct dirent *de; 873 struct dirhandle *h = id_to_ptr(req->fh); 874 TRACE("READDIR %p\n", h); 875 if (req->offset == 0) { 876 /* rewinddir() might have been called above us, so rewind here too */ 877 TRACE("calling rewinddir()\n"); 878 rewinddir(h->d); 879 } 880 de = readdir(h->d); 881 if (!de) { 882 fuse_status(fuse, hdr->unique, 0); 883 return; 884 } 885 fde->ino = FUSE_UNKNOWN_INO; 886 /* increment the offset so we can detect when rewinddir() seeks back to the beginning */ 887 fde->off = req->offset + 1; 888 fde->type = de->d_type; 889 fde->namelen = strlen(de->d_name); 890 memcpy(fde->name, de->d_name, fde->namelen + 1); 891 fuse_reply(fuse, hdr->unique, fde, 892 FUSE_DIRENT_ALIGN(sizeof(struct fuse_dirent) + fde->namelen)); 893 return; 894 } 895 case FUSE_RELEASEDIR: { /* release_in -> */ 896 struct fuse_release_in *req = data; 897 struct dirhandle *h = id_to_ptr(req->fh); 898 TRACE("RELEASEDIR %p\n",h); 899 closedir(h->d); 900 free(h); 901 fuse_status(fuse, hdr->unique, 0); 902 return; 903 } 904 // case FUSE_FSYNCDIR: 905 case FUSE_INIT: { /* init_in -> init_out */ 906 struct fuse_init_in *req = data; 907 struct fuse_init_out out; 908 909 TRACE("INIT ver=%d.%d maxread=%d flags=%x\n", 910 req->major, req->minor, req->max_readahead, req->flags); 911 912 out.major = FUSE_KERNEL_VERSION; 913 out.minor = FUSE_KERNEL_MINOR_VERSION; 914 out.max_readahead = req->max_readahead; 915 out.flags = FUSE_ATOMIC_O_TRUNC | FUSE_BIG_WRITES; 916 out.max_background = 32; 917 out.congestion_threshold = 32; 918 out.max_write = 256 * 1024; 919 920 fuse_reply(fuse, hdr->unique, &out, sizeof(out)); 921 return; 922 } 923 default: { 924 struct fuse_out_header h; 925 ERROR("NOTIMPL op=%d uniq=%llx nid=%llx\n", 926 hdr->opcode, hdr->unique, hdr->nodeid); 927 928 oops: 929 h.len = sizeof(h); 930 h.error = -ENOSYS; 931 h.unique = hdr->unique; 932 write(fuse->fd, &h, sizeof(h)); 933 break; 934 } 935 } 936 } 937 938 void handle_fuse_requests(struct fuse *fuse) 939 { 940 unsigned char req[256 * 1024 + 128]; 941 int len; 942 943 for (;;) { 944 len = read(fuse->fd, req, sizeof(req)); 945 if (len < 0) { 946 if (errno == EINTR) 947 continue; 948 ERROR("handle_fuse_requests: errno=%d\n", errno); 949 return; 950 } 951 handle_fuse_request(fuse, (void*) req, (void*) (req + sizeof(struct fuse_in_header)), len); 952 } 953 } 954 955 static int usage() 956 { 957 ERROR("usage: sdcard [-l -f] <path> <uid> <gid>\n\n\t-l force file names to lower case when creating new files\n\t-f fix up file system before starting (repairs bad file name case and group ownership)\n"); 958 return -1; 959 } 960 961 int main(int argc, char **argv) 962 { 963 struct fuse fuse; 964 char opts[256]; 965 int fd; 966 int res; 967 const char *path = NULL; 968 int i; 969 970 for (i = 1; i < argc; i++) { 971 char* arg = argv[i]; 972 if (!path) 973 path = arg; 974 else if (uid == -1) 975 uid = strtoul(arg, 0, 10); 976 else if (gid == -1) 977 gid = strtoul(arg, 0, 10); 978 else { 979 ERROR("too many arguments\n"); 980 return usage(); 981 } 982 } 983 984 if (!path) { 985 ERROR("no path specified\n"); 986 return usage(); 987 } 988 if (uid <= 0 || gid <= 0) { 989 ERROR("uid and gid must be nonzero\n"); 990 return usage(); 991 } 992 993 /* cleanup from previous instance, if necessary */ 994 umount2(MOUNT_POINT, 2); 995 996 fd = open("/dev/fuse", O_RDWR); 997 if (fd < 0){ 998 ERROR("cannot open fuse device (%d)\n", errno); 999 return -1; 1000 } 1001 1002 sprintf(opts, "fd=%i,rootmode=40000,default_permissions,allow_other," 1003 "user_id=%d,group_id=%d", fd, uid, gid); 1004 1005 res = mount("/dev/fuse", MOUNT_POINT, "fuse", MS_NOSUID | MS_NODEV, opts); 1006 if (res < 0) { 1007 ERROR("cannot mount fuse filesystem (%d)\n", errno); 1008 return -1; 1009 } 1010 1011 if (setgid(gid) < 0) { 1012 ERROR("cannot setgid!\n"); 1013 return -1; 1014 } 1015 if (setuid(uid) < 0) { 1016 ERROR("cannot setuid!\n"); 1017 return -1; 1018 } 1019 1020 fuse_init(&fuse, fd, path); 1021 1022 umask(0); 1023 handle_fuse_requests(&fuse); 1024 1025 return 0; 1026 } 1027