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_read_raw(sector, sector_size, 0, fd);
99 vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
100 for (i = 1; i < 11; i++)
102 exfat_read_raw(sector, sector_size, i * sector_size, fd);
103 vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
106 exfat_read_raw(sector, sector_size, i * sector_size, fd);
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_write_raw(ef->sb, sizeof(struct exfat_super_block), 0, ef->fd);
120 if (fsync(ef->fd) < 0)
122 exfat_error("fsync failed");
128 static int prepare_super_block(const struct exfat* ef)
130 if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
131 exfat_warn("volume was not unmounted cleanly");
136 ef->sb->volume_state = cpu_to_le16(
137 le16_to_cpu(ef->sb->volume_state) | EXFAT_STATE_MOUNTED);
138 return commit_super_block(ef);
141 int exfat_mount(struct exfat* ef, const char* spec, const char* options)
146 memset(ef, 0, sizeof(struct exfat));
148 parse_options(ef, options);
150 ef->fd = exfat_open(spec, ef->ro);
153 if (ef->ro || !match_option(options, "ro_fallback"))
155 ef->fd = exfat_open(spec, 1);
158 exfat_warn("device is write-protected, mounting read-only");
159 ef->ro_fallback = ef->ro = 1;
162 ef->sb = malloc(sizeof(struct exfat_super_block));
166 exfat_error("failed to allocate memory for the super block");
169 memset(ef->sb, 0, sizeof(struct exfat_super_block));
171 exfat_read_raw(ef->sb, sizeof(struct exfat_super_block), 0, ef->fd);
172 if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
176 exfat_error("exFAT file system is not found");
179 if (ef->sb->version.major != 1 || ef->sb->version.minor != 0)
182 exfat_error("unsupported exFAT version: %hhu.%hhu",
183 ef->sb->version.major, ef->sb->version.minor);
187 if (ef->sb->fat_count != 1)
191 exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
194 /* officially exFAT supports cluster size up to 32 MB */
195 if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
199 exfat_error("too big cluster size: 2^%d",
200 (int) ef->sb->sector_bits + (int) ef->sb->spc_bits);
204 ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
205 if (ef->zero_cluster == NULL)
209 exfat_error("failed to allocate zero sector");
212 /* use zero_cluster as a temporary buffer for VBR checksum verification */
213 if (verify_vbr_checksum(ef->zero_cluster, SECTOR_SIZE(*ef->sb),
216 free(ef->zero_cluster);
221 memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
223 ef->root = malloc(sizeof(struct exfat_node));
224 if (ef->root == NULL)
226 free(ef->zero_cluster);
229 exfat_error("failed to allocate root node");
232 memset(ef->root, 0, sizeof(struct exfat_node));
233 ef->root->flags = EXFAT_ATTRIB_DIR;
234 ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
235 ef->root->fptr_cluster = ef->root->start_cluster;
236 ef->root->name[0] = cpu_to_le16('\0');
237 ef->root->size = rootdir_size(ef);
238 /* exFAT does not have time attributes for the root directory */
241 /* always keep at least 1 reference to the root node */
242 exfat_get_node(ef->root);
244 rc = exfat_cache_directory(ef, ef->root);
247 if (ef->upcase == NULL)
249 exfat_error("upcase table is not found");
252 if (ef->cmap.chunk == NULL)
254 exfat_error("clusters bitmap is not found");
258 if (prepare_super_block(ef) != 0)
264 exfat_put_node(ef, ef->root);
265 exfat_reset_cache(ef);
267 free(ef->zero_cluster);
273 static void finalize_super_block(struct exfat* ef)
278 ef->sb->volume_state = cpu_to_le16(
279 le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);
281 /* Some implementations set the percentage of allocated space to 0xff
282 on FS creation and never update it. In this case leave it as is. */
283 if (ef->sb->allocated_percent != 0xff)
285 uint32_t free, total;
287 free = exfat_count_free_clusters(ef);
288 total = le32_to_cpu(ef->sb->cluster_count);
289 ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
292 commit_super_block(ef);
295 void exfat_unmount(struct exfat* ef)
297 exfat_put_node(ef, ef->root);
298 exfat_reset_cache(ef);
301 finalize_super_block(ef);
302 if (close(ef->fd) < 0) /* close descriptor immediately after fsync */
303 exfat_error("close failed");
305 free(ef->zero_cluster);
306 ef->zero_cluster = NULL;
307 free(ef->cmap.chunk);
308 ef->cmap.chunk = NULL;
313 ef->upcase_chars = 0;