3 exFAT file system implementation library.
5 Free exFAT implementation.
6 Copyright (C) 2010-2014 Andrew Nayenko
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation, either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License along
19 with this program; if not, write to the Free Software Foundation, Inc.,
20 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
29 #include <sys/types.h>
31 static uint64_t rootdir_size(const struct exfat* ef)
33 uint64_t clusters = 0;
34 cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
36 while (!CLUSTER_INVALID(rootdir_cluster))
39 /* root directory cannot be contiguous because there is no flag
41 rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
43 if (rootdir_cluster != EXFAT_CLUSTER_END)
45 exfat_error("bad cluster %#x while reading root directory",
49 return clusters * CLUSTER_SIZE(*ef->sb);
52 static const char* get_option(const char* options, const char* option_name)
55 size_t length = strlen(option_name);
57 for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
58 if ((p == options || p[-1] == ',') && p[length] == '=')
59 return p + length + 1;
63 static int get_int_option(const char* options, const char* option_name,
64 int base, int default_value)
66 const char* p = get_option(options, option_name);
70 return strtol(p, NULL, base);
73 static bool match_option(const char* options, const char* option_name)
76 size_t length = strlen(option_name);
78 for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
79 if ((p == options || p[-1] == ',') &&
80 (p[length] == ',' || p[length] == '\0'))
85 static void parse_options(struct exfat* ef, const char* options)
87 int sys_umask = umask(0);
90 umask(sys_umask); /* restore umask */
91 opt_umask = get_int_option(options, "umask", 8, sys_umask);
92 ef->dmask = get_int_option(options, "dmask", 8, opt_umask) & 0777;
93 ef->fmask = get_int_option(options, "fmask", 8, opt_umask) & 0777;
95 ef->uid = get_int_option(options, "uid", 10, geteuid());
96 ef->gid = get_int_option(options, "gid", 10, getegid());
98 ef->noatime = match_option(options, "noatime");
101 static bool verify_vbr_checksum(struct exfat_dev* dev, void* sector,
104 uint32_t vbr_checksum;
107 if (exfat_pread(dev, sector, sector_size, 0) < 0)
109 exfat_error("failed to read boot sector");
112 vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
113 for (i = 1; i < 11; i++)
115 if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
117 exfat_error("failed to read VBR sector");
120 vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
123 if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
125 exfat_error("failed to read VBR checksum sector");
128 for (i = 0; i < sector_size / sizeof(vbr_checksum); i++)
129 if (le32_to_cpu(((const le32_t*) sector)[i]) != vbr_checksum)
131 exfat_error("invalid VBR checksum 0x%x (expected 0x%x)",
132 le32_to_cpu(((const le32_t*) sector)[i]), vbr_checksum);
138 static int commit_super_block(const struct exfat* ef)
140 if (exfat_pwrite(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0)
142 exfat_error("failed to write super block");
145 return exfat_fsync(ef->dev);
148 static int prepare_super_block(const struct exfat* ef)
150 if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
151 exfat_warn("volume was not unmounted cleanly");
156 ef->sb->volume_state = cpu_to_le16(
157 le16_to_cpu(ef->sb->volume_state) | EXFAT_STATE_MOUNTED);
158 return commit_super_block(ef);
161 int exfat_mount(struct exfat* ef, const char* spec, const char* options)
164 enum exfat_mode mode;
167 memset(ef, 0, sizeof(struct exfat));
169 parse_options(ef, options);
171 if (match_option(options, "ro"))
172 mode = EXFAT_MODE_RO;
173 else if (match_option(options, "ro_fallback"))
174 mode = EXFAT_MODE_ANY;
176 mode = EXFAT_MODE_RW;
177 ef->dev = exfat_open(spec, mode);
180 if (exfat_get_mode(ef->dev) == EXFAT_MODE_RO)
182 if (mode == EXFAT_MODE_ANY)
188 ef->sb = malloc(sizeof(struct exfat_super_block));
191 exfat_close(ef->dev);
192 exfat_error("failed to allocate memory for the super block");
195 memset(ef->sb, 0, sizeof(struct exfat_super_block));
197 if (exfat_pread(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0)
199 exfat_close(ef->dev);
201 exfat_error("failed to read boot sector");
204 if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
206 exfat_close(ef->dev);
208 exfat_error("exFAT file system is not found");
211 /* sector cannot be smaller than 512 bytes */
212 if (ef->sb->sector_bits < 9)
214 exfat_close(ef->dev);
215 exfat_error("too small sector size: 2^%hhd", ef->sb->sector_bits);
219 /* officially exFAT supports cluster size up to 32 MB */
220 if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
222 exfat_close(ef->dev);
223 exfat_error("too big cluster size: 2^(%hhd+%hhd)",
224 ef->sb->sector_bits, ef->sb->spc_bits);
228 ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
229 if (ef->zero_cluster == NULL)
231 exfat_close(ef->dev);
233 exfat_error("failed to allocate zero sector");
236 /* use zero_cluster as a temporary buffer for VBR checksum verification */
237 if (!verify_vbr_checksum(ef->dev, ef->zero_cluster, SECTOR_SIZE(*ef->sb)))
239 free(ef->zero_cluster);
240 exfat_close(ef->dev);
244 memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
245 if (ef->sb->version.major != 1 || ef->sb->version.minor != 0)
247 free(ef->zero_cluster);
248 exfat_close(ef->dev);
249 exfat_error("unsupported exFAT version: %hhu.%hhu",
250 ef->sb->version.major, ef->sb->version.minor);
254 if (ef->sb->fat_count != 1)
256 free(ef->zero_cluster);
257 exfat_close(ef->dev);
258 exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
262 if (le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb) >
263 exfat_get_size(ef->dev))
265 free(ef->zero_cluster);
266 exfat_error("file system is larger than underlying device: "
267 "%"PRIu64" > %"PRIu64,
268 le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb),
269 exfat_get_size(ef->dev));
270 exfat_close(ef->dev);
275 ef->root = malloc(sizeof(struct exfat_node));
276 if (ef->root == NULL)
278 free(ef->zero_cluster);
279 exfat_close(ef->dev);
281 exfat_error("failed to allocate root node");
284 memset(ef->root, 0, sizeof(struct exfat_node));
285 ef->root->flags = EXFAT_ATTRIB_DIR;
286 ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
287 ef->root->fptr_cluster = ef->root->start_cluster;
288 ef->root->name[0] = cpu_to_le16('\0');
289 ef->root->size = rootdir_size(ef);
290 if (ef->root->size == 0)
293 free(ef->zero_cluster);
294 exfat_close(ef->dev);
298 /* exFAT does not have time attributes for the root directory */
301 /* always keep at least 1 reference to the root node */
302 exfat_get_node(ef->root);
304 rc = exfat_cache_directory(ef, ef->root);
307 if (ef->upcase == NULL)
309 exfat_error("upcase table is not found");
312 if (ef->cmap.chunk == NULL)
314 exfat_error("clusters bitmap is not found");
318 if (prepare_super_block(ef) != 0)
324 exfat_put_node(ef, ef->root);
325 exfat_reset_cache(ef);
327 free(ef->zero_cluster);
328 exfat_close(ef->dev);
333 static void finalize_super_block(struct exfat* ef)
338 ef->sb->volume_state = cpu_to_le16(
339 le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);
341 /* Some implementations set the percentage of allocated space to 0xff
342 on FS creation and never update it. In this case leave it as is. */
343 if (ef->sb->allocated_percent != 0xff)
345 uint32_t free, total;
347 free = exfat_count_free_clusters(ef);
348 total = le32_to_cpu(ef->sb->cluster_count);
349 ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
352 commit_super_block(ef); /* ignore return code */
355 void exfat_unmount(struct exfat* ef)
357 exfat_flush(ef); /* ignore return code */
358 exfat_put_node(ef, ef->root);
359 exfat_reset_cache(ef);
362 finalize_super_block(ef);
363 exfat_close(ef->dev); /* close descriptor immediately after fsync */
365 free(ef->zero_cluster);
366 ef->zero_cluster = NULL;
367 free(ef->cmap.chunk);
368 ef->cmap.chunk = NULL;
373 ef->upcase_chars = 0;