3 exFAT file system implementation library.
5 Copyright (C) 2009, 2010 Andrew Nayenko
7 This program is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
26 #include <sys/types.h>
28 static uint64_t rootdir_size(const struct exfat* ef)
30 uint64_t clusters = 0;
31 cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
33 while (!CLUSTER_INVALID(rootdir_cluster))
36 /* root directory cannot be contiguous because there is no flag
38 rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
40 return clusters * CLUSTER_SIZE(*ef->sb);
43 static const char* get_option(const char* options, const char* option_name)
46 size_t length = strlen(option_name);
48 for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
49 if ((p == options || p[-1] == ',') && p[length] == '=')
50 return p + length + 1;
54 static int get_int_option(const char* options, const char* option_name,
55 int base, int default_value)
57 const char* p = get_option(options, option_name);
61 return strtol(p, NULL, base);
64 static int match_option(const char* options, const char* option_name)
67 size_t length = strlen(option_name);
69 for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
70 if ((p == options || p[-1] == ',') &&
71 (p[length] == ',' || p[length] == '\0'))
76 static void parse_options(struct exfat* ef, const char* options)
78 int sys_umask = umask(0);
81 umask(sys_umask); /* restore umask */
82 opt_umask = get_int_option(options, "umask", 8, sys_umask);
83 ef->dmask = get_int_option(options, "dmask", 8, opt_umask) & 0777;
84 ef->fmask = get_int_option(options, "fmask", 8, opt_umask) & 0777;
86 ef->uid = get_int_option(options, "uid", 10, geteuid());
87 ef->gid = get_int_option(options, "gid", 10, getegid());
89 ef->ro = match_option(options, "ro");
90 ef->noatime = match_option(options, "noatime");
93 static int verify_vbr_checksum(void* sector, off_t sector_size, int fd)
95 uint32_t vbr_checksum;
98 exfat_pread(fd, sector, sector_size, 0);
99 vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
100 for (i = 1; i < 11; i++)
102 exfat_pread(fd, sector, sector_size, i * sector_size);
103 vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
106 exfat_pread(fd, sector, sector_size, i * sector_size);
107 for (i = 0; i < sector_size / sizeof(vbr_checksum); i++)
108 if (le32_to_cpu(((const le32_t*) sector)[i]) != vbr_checksum)
110 exfat_error("invalid VBR checksum 0x%x (expected 0x%x)",
111 le32_to_cpu(((const le32_t*) sector)[i]), vbr_checksum);
117 static int commit_super_block(const struct exfat* ef)
119 exfat_pwrite(ef->fd, ef->sb, sizeof(struct exfat_super_block), 0);
120 return exfat_fsync(ef->fd);
123 static int prepare_super_block(const struct exfat* ef)
125 if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
126 exfat_warn("volume was not unmounted cleanly");
131 ef->sb->volume_state = cpu_to_le16(
132 le16_to_cpu(ef->sb->volume_state) | EXFAT_STATE_MOUNTED);
133 return commit_super_block(ef);
136 int exfat_mount(struct exfat* ef, const char* spec, const char* options)
141 memset(ef, 0, sizeof(struct exfat));
143 parse_options(ef, options);
145 ef->fd = exfat_open(spec, ef->ro);
148 if (ef->ro || !match_option(options, "ro_fallback"))
150 ef->fd = exfat_open(spec, 1);
153 exfat_warn("device is write-protected, mounting read-only");
154 ef->ro_fallback = ef->ro = 1;
157 ef->sb = malloc(sizeof(struct exfat_super_block));
161 exfat_error("failed to allocate memory for the super block");
164 memset(ef->sb, 0, sizeof(struct exfat_super_block));
166 exfat_pread(ef->fd, ef->sb, sizeof(struct exfat_super_block), 0);
167 if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
171 exfat_error("exFAT file system is not found");
174 if (ef->sb->version.major != 1 || ef->sb->version.minor != 0)
177 exfat_error("unsupported exFAT version: %hhu.%hhu",
178 ef->sb->version.major, ef->sb->version.minor);
182 if (ef->sb->fat_count != 1)
186 exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
189 /* officially exFAT supports cluster size up to 32 MB */
190 if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
194 exfat_error("too big cluster size: 2^%d",
195 (int) ef->sb->sector_bits + (int) ef->sb->spc_bits);
199 ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
200 if (ef->zero_cluster == NULL)
204 exfat_error("failed to allocate zero sector");
207 /* use zero_cluster as a temporary buffer for VBR checksum verification */
208 if (verify_vbr_checksum(ef->zero_cluster, SECTOR_SIZE(*ef->sb),
211 free(ef->zero_cluster);
216 memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
218 ef->root = malloc(sizeof(struct exfat_node));
219 if (ef->root == NULL)
221 free(ef->zero_cluster);
224 exfat_error("failed to allocate root node");
227 memset(ef->root, 0, sizeof(struct exfat_node));
228 ef->root->flags = EXFAT_ATTRIB_DIR;
229 ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
230 ef->root->fptr_cluster = ef->root->start_cluster;
231 ef->root->name[0] = cpu_to_le16('\0');
232 ef->root->size = rootdir_size(ef);
233 /* exFAT does not have time attributes for the root directory */
236 /* always keep at least 1 reference to the root node */
237 exfat_get_node(ef->root);
239 rc = exfat_cache_directory(ef, ef->root);
242 if (ef->upcase == NULL)
244 exfat_error("upcase table is not found");
247 if (ef->cmap.chunk == NULL)
249 exfat_error("clusters bitmap is not found");
253 if (prepare_super_block(ef) != 0)
259 exfat_put_node(ef, ef->root);
260 exfat_reset_cache(ef);
262 free(ef->zero_cluster);
268 static void finalize_super_block(struct exfat* ef)
273 ef->sb->volume_state = cpu_to_le16(
274 le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);
276 /* Some implementations set the percentage of allocated space to 0xff
277 on FS creation and never update it. In this case leave it as is. */
278 if (ef->sb->allocated_percent != 0xff)
280 uint32_t free, total;
282 free = exfat_count_free_clusters(ef);
283 total = le32_to_cpu(ef->sb->cluster_count);
284 ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
287 commit_super_block(ef);
290 void exfat_unmount(struct exfat* ef)
292 exfat_put_node(ef, ef->root);
293 exfat_reset_cache(ef);
296 finalize_super_block(ef);
297 exfat_close(ef->fd); /* close descriptor immediately after fsync */
299 free(ef->zero_cluster);
300 ef->zero_cluster = NULL;
301 free(ef->cmap.chunk);
302 ef->cmap.chunk = NULL;
307 ef->upcase_chars = 0;