Changeset b79d450 in mainline for uspace/srv/fs/fat/fat_ops.c
- Timestamp:
- 2010-01-27T20:35:49Z (14 years ago)
- Branches:
- lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export
- Children:
- fb6f1a5
- Parents:
- fccc236 (diff), 95e6c4f (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
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-
- 1 edited
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uspace/srv/fs/fat/fat_ops.c
rfccc236 rb79d450 290 290 291 291 *nodepp = nodep; 292 return EOK; 293 } 294 295 /** Perform basic sanity checks on the file system. 296 * 297 * Verify if values of boot sector fields are sane. Also verify media 298 * descriptor. This is used to rule out cases when a device obviously 299 * does not contain a fat file system. 300 */ 301 static int fat_sanity_check(fat_bs_t *bs, dev_handle_t dev_handle) 302 { 303 fat_cluster_t e0, e1; 304 unsigned fat_no; 305 int rc; 306 307 /* Check number of FATs. */ 308 if (bs->fatcnt == 0) 309 return ENOTSUP; 310 311 /* Check total number of sectors. */ 312 313 if (bs->totsec16 == 0 && bs->totsec32 == 0) 314 return ENOTSUP; 315 316 if (bs->totsec16 != 0 && bs->totsec32 != 0 && 317 bs->totsec16 != bs->totsec32) 318 return ENOTSUP; 319 320 /* Check media descriptor. Must be between 0xf0 and 0xff. */ 321 if ((bs->mdesc & 0xf0) != 0xf0) 322 return ENOTSUP; 323 324 /* Check number of sectors per FAT. */ 325 if (bs->sec_per_fat == 0) 326 return ENOTSUP; 327 328 /* 329 * Check that the root directory entries take up whole blocks. 330 * This check is rather strict, but it allows us to treat the root 331 * directory and non-root directories uniformly in some places. 332 * It can be removed provided that functions such as fat_read() are 333 * sanitized to support file systems with this property. 334 */ 335 if ((uint16_t_le2host(bs->root_ent_max) * sizeof(fat_dentry_t)) % 336 uint16_t_le2host(bs->bps) != 0) 337 return ENOTSUP; 338 339 /* Check signature of each FAT. */ 340 341 for (fat_no = 0; fat_no < bs->fatcnt; fat_no++) { 342 rc = fat_get_cluster(bs, dev_handle, fat_no, 0, &e0); 343 if (rc != EOK) 344 return EIO; 345 346 rc = fat_get_cluster(bs, dev_handle, fat_no, 1, &e1); 347 if (rc != EOK) 348 return EIO; 349 350 /* Check that first byte of FAT contains the media descriptor. */ 351 if ((e0 & 0xff) != bs->mdesc) 352 return ENOTSUP; 353 354 /* 355 * Check that remaining bits of the first two entries are 356 * set to one. 357 */ 358 if ((e0 >> 8) != 0xff || e1 != 0xffff) 359 return ENOTSUP; 360 } 361 292 362 return EOK; 293 363 } … … 981 1051 } 982 1052 1053 /* Do some simple sanity checks on the file system. */ 1054 rc = fat_sanity_check(bs, dev_handle); 1055 if (rc != EOK) { 1056 block_fini(dev_handle); 1057 ipc_answer_0(rid, rc); 1058 return; 1059 } 1060 983 1061 rc = fat_idx_init_by_dev_handle(dev_handle); 984 1062 if (rc != EOK) { … … 1037 1115 { 1038 1116 libfs_mount(&fat_libfs_ops, fat_reg.fs_handle, rid, request); 1117 } 1118 1119 void fat_unmounted(ipc_callid_t rid, ipc_call_t *request) 1120 { 1121 ipc_answer_0(rid, ENOTSUP); 1122 } 1123 1124 void fat_unmount(ipc_callid_t rid, ipc_call_t *request) 1125 { 1126 libfs_unmount(&fat_libfs_ops, rid, request); 1039 1127 } 1040 1128
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