blob: 0d6ce9ead7514b08283d1e0fe8f58b6edcec3fdc [file] [log] [blame]
bigbiff bigbiff9c754052013-01-09 09:09:08 -05001/*
2 mount.c (22.10.09)
3 exFAT file system implementation library.
4
bigbiff bigbiff61cdc022013-08-08 08:35:06 -04005 Free exFAT implementation.
Matt Mower09ef1e42015-12-13 11:29:45 -06006 Copyright (C) 2010-2015 Andrew Nayenko
bigbiff bigbiff9c754052013-01-09 09:09:08 -05007
bigbiff bigbiff61cdc022013-08-08 08:35:06 -04008 This program is free software; you can redistribute it and/or modify
bigbiff bigbiff9c754052013-01-09 09:09:08 -05009 it under the terms of the GNU General Public License as published by
bigbiff bigbiff61cdc022013-08-08 08:35:06 -040010 the Free Software Foundation, either version 2 of the License, or
bigbiff bigbiff9c754052013-01-09 09:09:08 -050011 (at your option) any later version.
12
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.
17
bigbiff bigbiff61cdc022013-08-08 08:35:06 -040018 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.
bigbiff bigbiff9c754052013-01-09 09:09:08 -050021*/
22
23#include "exfat.h"
24#include <string.h>
25#include <stdlib.h>
26#include <errno.h>
Matt Mower09ef1e42015-12-13 11:29:45 -060027#include <inttypes.h>
bigbiff bigbiff9c754052013-01-09 09:09:08 -050028#include <unistd.h>
29#include <sys/types.h>
30
31static uint64_t rootdir_size(const struct exfat* ef)
32{
Matt Mower09ef1e42015-12-13 11:29:45 -060033 uint32_t clusters = 0;
34 uint32_t clusters_max = le32_to_cpu(ef->sb->cluster_count);
bigbiff bigbiff9c754052013-01-09 09:09:08 -050035 cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
36
Matt Mower09ef1e42015-12-13 11:29:45 -060037 /* Iterate all clusters of the root directory to calculate its size.
38 It can't be contiguous because there is no flag to indicate this. */
39 do
bigbiff bigbiff9c754052013-01-09 09:09:08 -050040 {
Matt Mower09ef1e42015-12-13 11:29:45 -060041 if (clusters == clusters_max) /* infinite loop detected */
42 {
43 exfat_error("root directory cannot occupy all %d clusters",
44 clusters);
45 return 0;
46 }
47 if (CLUSTER_INVALID(rootdir_cluster))
48 {
49 exfat_error("bad cluster %#x while reading root directory",
50 rootdir_cluster);
51 return 0;
52 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -050053 rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
Matt Mower09ef1e42015-12-13 11:29:45 -060054 clusters++;
bigbiff bigbiff9c754052013-01-09 09:09:08 -050055 }
Matt Mower09ef1e42015-12-13 11:29:45 -060056 while (rootdir_cluster != EXFAT_CLUSTER_END);
57
58 return (uint64_t) clusters * CLUSTER_SIZE(*ef->sb);
bigbiff bigbiff9c754052013-01-09 09:09:08 -050059}
60
61static const char* get_option(const char* options, const char* option_name)
62{
63 const char* p;
64 size_t length = strlen(option_name);
65
66 for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
67 if ((p == options || p[-1] == ',') && p[length] == '=')
68 return p + length + 1;
69 return NULL;
70}
71
72static int get_int_option(const char* options, const char* option_name,
73 int base, int default_value)
74{
75 const char* p = get_option(options, option_name);
76
77 if (p == NULL)
78 return default_value;
79 return strtol(p, NULL, base);
80}
81
82static bool match_option(const char* options, const char* option_name)
83{
84 const char* p;
85 size_t length = strlen(option_name);
86
87 for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
88 if ((p == options || p[-1] == ',') &&
89 (p[length] == ',' || p[length] == '\0'))
90 return true;
91 return false;
92}
93
94static void parse_options(struct exfat* ef, const char* options)
95{
bigbiff bigbiff9c754052013-01-09 09:09:08 -050096 int opt_umask;
97
Matt Mower09ef1e42015-12-13 11:29:45 -060098 opt_umask = get_int_option(options, "umask", 8, 0);
99 ef->dmask = get_int_option(options, "dmask", 8, opt_umask);
100 ef->fmask = get_int_option(options, "fmask", 8, opt_umask);
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500101
102 ef->uid = get_int_option(options, "uid", 10, geteuid());
103 ef->gid = get_int_option(options, "gid", 10, getegid());
104
105 ef->noatime = match_option(options, "noatime");
106}
107
Matt Mower09ef1e42015-12-13 11:29:45 -0600108static bool verify_vbr_checksum(struct exfat_dev* dev, void* sector,
109 off_t sector_size)
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500110{
111 uint32_t vbr_checksum;
112 int i;
113
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400114 if (exfat_pread(dev, sector, sector_size, 0) < 0)
115 {
116 exfat_error("failed to read boot sector");
Matt Mower09ef1e42015-12-13 11:29:45 -0600117 return false;
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400118 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500119 vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
120 for (i = 1; i < 11; i++)
121 {
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400122 if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
123 {
124 exfat_error("failed to read VBR sector");
Matt Mower09ef1e42015-12-13 11:29:45 -0600125 return false;
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400126 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500127 vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
128 vbr_checksum);
129 }
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400130 if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
131 {
132 exfat_error("failed to read VBR checksum sector");
Matt Mower09ef1e42015-12-13 11:29:45 -0600133 return false;
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400134 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500135 for (i = 0; i < sector_size / sizeof(vbr_checksum); i++)
136 if (le32_to_cpu(((const le32_t*) sector)[i]) != vbr_checksum)
137 {
138 exfat_error("invalid VBR checksum 0x%x (expected 0x%x)",
139 le32_to_cpu(((const le32_t*) sector)[i]), vbr_checksum);
Matt Mower09ef1e42015-12-13 11:29:45 -0600140 return false;
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500141 }
Matt Mower09ef1e42015-12-13 11:29:45 -0600142 return true;
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500143}
144
145static int commit_super_block(const struct exfat* ef)
146{
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400147 if (exfat_pwrite(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0)
148 {
149 exfat_error("failed to write super block");
150 return 1;
151 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500152 return exfat_fsync(ef->dev);
153}
154
155static int prepare_super_block(const struct exfat* ef)
156{
157 if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
158 exfat_warn("volume was not unmounted cleanly");
159
160 if (ef->ro)
161 return 0;
162
163 ef->sb->volume_state = cpu_to_le16(
164 le16_to_cpu(ef->sb->volume_state) | EXFAT_STATE_MOUNTED);
165 return commit_super_block(ef);
166}
167
168int exfat_mount(struct exfat* ef, const char* spec, const char* options)
169{
170 int rc;
171 enum exfat_mode mode;
172
173 exfat_tzset();
174 memset(ef, 0, sizeof(struct exfat));
175
176 parse_options(ef, options);
177
178 if (match_option(options, "ro"))
179 mode = EXFAT_MODE_RO;
180 else if (match_option(options, "ro_fallback"))
181 mode = EXFAT_MODE_ANY;
182 else
183 mode = EXFAT_MODE_RW;
184 ef->dev = exfat_open(spec, mode);
185 if (ef->dev == NULL)
186 return -EIO;
187 if (exfat_get_mode(ef->dev) == EXFAT_MODE_RO)
188 {
189 if (mode == EXFAT_MODE_ANY)
190 ef->ro = -1;
191 else
192 ef->ro = 1;
193 }
194
195 ef->sb = malloc(sizeof(struct exfat_super_block));
196 if (ef->sb == NULL)
197 {
198 exfat_close(ef->dev);
199 exfat_error("failed to allocate memory for the super block");
200 return -ENOMEM;
201 }
202 memset(ef->sb, 0, sizeof(struct exfat_super_block));
203
bigbiff bigbiff61cdc022013-08-08 08:35:06 -0400204 if (exfat_pread(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0)
205 {
206 exfat_close(ef->dev);
207 free(ef->sb);
208 exfat_error("failed to read boot sector");
209 return -EIO;
210 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500211 if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
212 {
213 exfat_close(ef->dev);
214 free(ef->sb);
215 exfat_error("exFAT file system is not found");
216 return -EIO;
217 }
Matt Mower09ef1e42015-12-13 11:29:45 -0600218 /* sector cannot be smaller than 512 bytes */
219 if (ef->sb->sector_bits < 9)
bigbiffc40c1c52014-11-01 09:34:57 -0400220 {
221 exfat_close(ef->dev);
Matt Mower09ef1e42015-12-13 11:29:45 -0600222 exfat_error("too small sector size: 2^%hhd", ef->sb->sector_bits);
bigbiffc40c1c52014-11-01 09:34:57 -0400223 free(ef->sb);
224 return -EIO;
225 }
bigbiffc40c1c52014-11-01 09:34:57 -0400226 /* officially exFAT supports cluster size up to 32 MB */
227 if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
228 {
229 exfat_close(ef->dev);
Matt Mower09ef1e42015-12-13 11:29:45 -0600230 exfat_error("too big cluster size: 2^(%hhd+%hhd)",
231 ef->sb->sector_bits, ef->sb->spc_bits);
bigbiffc40c1c52014-11-01 09:34:57 -0400232 free(ef->sb);
bigbiffc40c1c52014-11-01 09:34:57 -0400233 return -EIO;
234 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500235 ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
236 if (ef->zero_cluster == NULL)
237 {
238 exfat_close(ef->dev);
239 free(ef->sb);
240 exfat_error("failed to allocate zero sector");
241 return -ENOMEM;
242 }
243 /* use zero_cluster as a temporary buffer for VBR checksum verification */
Matt Mower09ef1e42015-12-13 11:29:45 -0600244 if (!verify_vbr_checksum(ef->dev, ef->zero_cluster, SECTOR_SIZE(*ef->sb)))
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500245 {
246 free(ef->zero_cluster);
247 exfat_close(ef->dev);
248 free(ef->sb);
249 return -EIO;
250 }
251 memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
Matt Mower09ef1e42015-12-13 11:29:45 -0600252 if (ef->sb->version.major != 1 || ef->sb->version.minor != 0)
253 {
254 free(ef->zero_cluster);
255 exfat_close(ef->dev);
256 exfat_error("unsupported exFAT version: %hhu.%hhu",
257 ef->sb->version.major, ef->sb->version.minor);
258 free(ef->sb);
259 return -EIO;
260 }
261 if (ef->sb->fat_count != 1)
262 {
263 free(ef->zero_cluster);
264 exfat_close(ef->dev);
265 exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
266 free(ef->sb);
267 return -EIO;
268 }
269 if (le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb) >
270 exfat_get_size(ef->dev))
271 {
272 /* this can cause I/O errors later but we don't fail mounting to let
273 user rescue data */
274 exfat_warn("file system is larger than underlying device: "
275 "%"PRIu64" > %"PRIu64,
276 le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb),
277 exfat_get_size(ef->dev));
278 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500279
280 ef->root = malloc(sizeof(struct exfat_node));
281 if (ef->root == NULL)
282 {
283 free(ef->zero_cluster);
284 exfat_close(ef->dev);
285 free(ef->sb);
286 exfat_error("failed to allocate root node");
287 return -ENOMEM;
288 }
289 memset(ef->root, 0, sizeof(struct exfat_node));
290 ef->root->flags = EXFAT_ATTRIB_DIR;
291 ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
292 ef->root->fptr_cluster = ef->root->start_cluster;
293 ef->root->name[0] = cpu_to_le16('\0');
294 ef->root->size = rootdir_size(ef);
Matt Mower09ef1e42015-12-13 11:29:45 -0600295 if (ef->root->size == 0)
296 {
297 free(ef->root);
298 free(ef->zero_cluster);
299 exfat_close(ef->dev);
300 free(ef->sb);
301 return -EIO;
302 }
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500303 /* exFAT does not have time attributes for the root directory */
304 ef->root->mtime = 0;
305 ef->root->atime = 0;
306 /* always keep at least 1 reference to the root node */
307 exfat_get_node(ef->root);
308
309 rc = exfat_cache_directory(ef, ef->root);
310 if (rc != 0)
311 goto error;
312 if (ef->upcase == NULL)
313 {
314 exfat_error("upcase table is not found");
315 goto error;
316 }
317 if (ef->cmap.chunk == NULL)
318 {
319 exfat_error("clusters bitmap is not found");
320 goto error;
321 }
322
323 if (prepare_super_block(ef) != 0)
324 goto error;
325
326 return 0;
327
328error:
329 exfat_put_node(ef, ef->root);
330 exfat_reset_cache(ef);
331 free(ef->root);
332 free(ef->zero_cluster);
333 exfat_close(ef->dev);
334 free(ef->sb);
335 return -EIO;
336}
337
338static void finalize_super_block(struct exfat* ef)
339{
340 if (ef->ro)
341 return;
342
343 ef->sb->volume_state = cpu_to_le16(
344 le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);
345
346 /* Some implementations set the percentage of allocated space to 0xff
347 on FS creation and never update it. In this case leave it as is. */
348 if (ef->sb->allocated_percent != 0xff)
349 {
350 uint32_t free, total;
351
352 free = exfat_count_free_clusters(ef);
353 total = le32_to_cpu(ef->sb->cluster_count);
354 ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
355 }
356
Matt Mower09ef1e42015-12-13 11:29:45 -0600357 commit_super_block(ef); /* ignore return code */
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500358}
359
360void exfat_unmount(struct exfat* ef)
361{
Matt Mower09ef1e42015-12-13 11:29:45 -0600362 exfat_flush_nodes(ef); /* ignore return code */
363 exfat_flush(ef); /* ignore return code */
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500364 exfat_put_node(ef, ef->root);
365 exfat_reset_cache(ef);
366 free(ef->root);
367 ef->root = NULL;
368 finalize_super_block(ef);
369 exfat_close(ef->dev); /* close descriptor immediately after fsync */
370 ef->dev = NULL;
371 free(ef->zero_cluster);
372 ef->zero_cluster = NULL;
373 free(ef->cmap.chunk);
374 ef->cmap.chunk = NULL;
375 free(ef->sb);
376 ef->sb = NULL;
377 free(ef->upcase);
378 ef->upcase = NULL;
379 ef->upcase_chars = 0;
380}