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bigbiff bigbiff9c754052013-01-09 09:09:08 -05001/*
2 io.c (02.09.09)
3 exFAT file system implementation library.
4
5 Copyright (C) 2010-2012 Andrew Nayenko
6
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.
11
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.
16
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/>.
19*/
20
21#include "exfat.h"
22#include <inttypes.h>
23#include <sys/types.h>
24#include <sys/stat.h>
25#include <sys/mount.h>
26#include <fcntl.h>
27#include <unistd.h>
28#include <string.h>
29#ifdef __APPLE__
30#include <sys/disk.h>
31#endif
32#ifdef USE_UBLIO
33#include <sys/uio.h>
34#include <ublio.h>
35#endif
36
37struct exfat_dev
38{
39 int fd;
40 enum exfat_mode mode;
41 off64_t size; /* in bytes */
42#ifdef USE_UBLIO
43 off64_t pos;
44 ublio_filehandle_t ufh;
45#endif
46};
47
48static int open_ro(const char* spec)
49{
50 return open(spec, O_RDONLY);
51}
52
53static int open_rw(const char* spec)
54{
55 int fd = open(spec, O_RDWR);
56#ifdef __linux__
57 int ro = 0;
58
59 /*
60 This ioctl is needed because after "blockdev --setro" kernel still
61 allows to open the device in read-write mode but fails writes.
62 */
63 if (fd != -1 && ioctl(fd, BLKROGET, &ro) == 0 && ro)
64 {
65 close(fd);
66 return -1;
67 }
68#endif
69 return fd;
70}
71
72struct exfat_dev* exfat_open(const char* spec, enum exfat_mode mode)
73{
74 struct exfat_dev* dev;
75 struct stat stbuf;
76#ifdef USE_UBLIO
77 struct ublio_param up;
78#endif
79
80 dev = malloc(sizeof(struct exfat_dev));
81 if (dev == NULL)
82 {
83 exfat_error("failed to allocate memory for device structure");
84 return NULL;
85 }
86
87 switch (mode)
88 {
89 case EXFAT_MODE_RO:
90 dev->fd = open_ro(spec);
91 if (dev->fd == -1)
92 {
93 free(dev);
94 exfat_error("failed to open `%s' in read-only mode", spec);
95 return NULL;
96 }
97 dev->mode = EXFAT_MODE_RO;
98 break;
99 case EXFAT_MODE_RW:
100 dev->fd = open_rw(spec);
101 if (dev->fd == -1)
102 {
103 free(dev);
104 exfat_error("failed to open `%s' in read-write mode", spec);
105 return NULL;
106 }
107 dev->mode = EXFAT_MODE_RW;
108 break;
109 case EXFAT_MODE_ANY:
110 dev->fd = open_rw(spec);
111 if (dev->fd != -1)
112 {
113 dev->mode = EXFAT_MODE_RW;
114 break;
115 }
116 dev->fd = open_ro(spec);
117 if (dev->fd != -1)
118 {
119 dev->mode = EXFAT_MODE_RO;
120 exfat_warn("`%s' is write-protected, mounting read-only", spec);
121 break;
122 }
123 free(dev);
124 exfat_error("failed to open `%s'", spec);
125 return NULL;
126 }
127
128 if (fstat(dev->fd, &stbuf) != 0)
129 {
130 close(dev->fd);
131 free(dev);
132 exfat_error("failed to fstat `%s'", spec);
133 return NULL;
134 }
135 if (!S_ISBLK(stbuf.st_mode) &&
136 !S_ISCHR(stbuf.st_mode) &&
137 !S_ISREG(stbuf.st_mode))
138 {
139 close(dev->fd);
140 free(dev);
141 exfat_error("`%s' is neither a device, nor a regular file", spec);
142 return NULL;
143 }
144
145#ifdef __APPLE__
146 if (!S_ISREG(stbuf.st_mode))
147 {
148 uint32_t block_size = 0;
149 uint64_t blocks = 0;
150
151 if (ioctl(dev->fd, DKIOCGETBLOCKSIZE, &block_size) != 0)
152 {
153 close(dev->fd);
154 free(dev);
155 exfat_error("failed to get block size");
156 return NULL;
157 }
158 if (ioctl(dev->fd, DKIOCGETBLOCKCOUNT, &blocks) != 0)
159 {
160 close(dev->fd);
161 free(dev);
162 exfat_error("failed to get blocks count");
163 return NULL;
164 }
165 dev->size = blocks * block_size;
166 }
167 else
168#endif
169 {
170 /* works for Linux, FreeBSD, Solaris */
171 dev->size = exfat_seek(dev, 0, SEEK_END);
172 if (dev->size <= 0)
173 {
174 close(dev->fd);
175 free(dev);
176 exfat_error("failed to get size of `%s'", spec);
177 return NULL;
178 }
179 if (exfat_seek(dev, 0, SEEK_SET) == -1)
180 {
181 close(dev->fd);
182 free(dev);
183 exfat_error("failed to seek to the beginning of `%s'", spec);
184 return NULL;
185 }
186 }
187
188#ifdef USE_UBLIO
189 memset(&up, 0, sizeof(struct ublio_param));
190 up.up_blocksize = 256 * 1024;
191 up.up_items = 64;
192 up.up_grace = 32;
193 up.up_priv = &dev->fd;
194
195 dev->pos = 0;
196 dev->ufh = ublio_open(&up);
197 if (dev->ufh == NULL)
198 {
199 close(dev->fd);
200 free(dev);
201 exfat_error("failed to initialize ublio");
202 return NULL;
203 }
204#endif
205
206 return dev;
207}
208
209int exfat_close(struct exfat_dev* dev)
210{
211#ifdef USE_UBLIO
212 if (ublio_close(dev->ufh) != 0)
213 exfat_error("failed to close ublio");
214#endif
215 if (close(dev->fd) != 0)
216 {
217 free(dev);
218 exfat_error("failed to close device");
219 return 1;
220 }
221 free(dev);
222 return 0;
223}
224
225int exfat_fsync(struct exfat_dev* dev)
226{
227#ifdef USE_UBLIO
228 if (ublio_fsync(dev->ufh) != 0)
229#else
230 if (fsync(dev->fd) != 0)
231#endif
232 {
233 exfat_error("fsync failed");
234 return 1;
235 }
236 return 0;
237}
238
239enum exfat_mode exfat_get_mode(const struct exfat_dev* dev)
240{
241 return dev->mode;
242}
243
244off64_t exfat_get_size(const struct exfat_dev* dev)
245{
246 return dev->size;
247}
248
249off64_t exfat_seek(struct exfat_dev* dev, off64_t offset, int whence)
250{
251#ifdef USE_UBLIO
252 /* XXX SEEK_CUR will be handled incorrectly */
253 return dev->pos = lseek64(dev->fd, offset, whence);
254#else
255 return lseek64(dev->fd, offset, whence);
256#endif
257}
258
259ssize_t exfat_read(struct exfat_dev* dev, void* buffer, size_t size)
260{
261#ifdef USE_UBLIO
262 ssize_t result = ublio_pread(dev->ufh, buffer, size, dev->pos);
263 if (result >= 0)
264 dev->pos += size;
265 return result;
266#else
267 return read(dev->fd, buffer, size);
268#endif
269}
270
271ssize_t exfat_write(struct exfat_dev* dev, const void* buffer, size_t size)
272{
273#ifdef USE_UBLIO
274 ssize_t result = ublio_pwrite(dev->ufh, buffer, size, dev->pos);
275 if (result >= 0)
276 dev->pos += size;
277 return result;
278#else
279 return write(dev->fd, buffer, size);
280#endif
281}
282
283void exfat_pread(struct exfat_dev* dev, void* buffer, size_t size,
284 off64_t offset)
285{
286#ifdef USE_UBLIO
287 if (ublio_pread(dev->ufh, buffer, size, offset) != size)
288#else
289 if (pread64(dev->fd, buffer, size, offset) != size)
290#endif
291 exfat_bug("failed to read %zu bytes from file at %"PRIu64, size,
292 (uint64_t) offset);
293}
294
295void exfat_pwrite(struct exfat_dev* dev, const void* buffer, size_t size,
296 off64_t offset)
297{
298#ifdef USE_UBLIO
299 if (ublio_pwrite(dev->ufh, buffer, size, offset) != size)
300#else
301 if (pwrite64(dev->fd, buffer, size, offset) != size)
302#endif
303 exfat_bug("failed to write %zu bytes to file at %"PRIu64, size,
304 (uint64_t) offset);
305}
306
307ssize_t exfat_generic_pread(const struct exfat* ef, struct exfat_node* node,
308 void* buffer, size_t size, off64_t offset)
309{
310 cluster_t cluster;
311 char* bufp = buffer;
312 off64_t lsize, loffset, remainder;
313
314 if (offset >= node->size)
315 return 0;
316 if (size == 0)
317 return 0;
318
319 cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
320 if (CLUSTER_INVALID(cluster))
321 {
322 exfat_error("invalid cluster 0x%x while reading", cluster);
323 return -1;
324 }
325
326 loffset = offset % CLUSTER_SIZE(*ef->sb);
327 remainder = MIN(size, node->size - offset);
328 while (remainder > 0)
329 {
330 if (CLUSTER_INVALID(cluster))
331 {
332 exfat_error("invalid cluster 0x%x while reading", cluster);
333 return -1;
334 }
335 lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
336 exfat_pread(ef->dev, bufp, lsize, exfat_c2o(ef, cluster) + loffset);
337 bufp += lsize;
338 loffset = 0;
339 remainder -= lsize;
340 cluster = exfat_next_cluster(ef, node, cluster);
341 }
342 if (!ef->ro && !ef->noatime)
343 exfat_update_atime(node);
Dees_Troyb8fdac72013-01-25 19:42:52 +0000344 return MIN(size, node->size - offset) - remainder;
bigbiff bigbiff9c754052013-01-09 09:09:08 -0500345}
346
347ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
348 const void* buffer, size_t size, off64_t offset)
349{
350 cluster_t cluster;
351 const char* bufp = buffer;
352 off64_t lsize, loffset, remainder;
353 printf("node: %s\n", node);
354 if (offset + size > node->size)
355 if (exfat_truncate(ef, node, offset + size) != 0)
356 return -1;
357 if (size == 0)
358 return 0;
359
360 cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
361 if (CLUSTER_INVALID(cluster))
362 {
363 exfat_error("invalid cluster 0x%x while writing", cluster);
364 return -1;
365 }
366
367 loffset = offset % CLUSTER_SIZE(*ef->sb);
368 remainder = size;
369 while (remainder > 0)
370 {
371 if (CLUSTER_INVALID(cluster))
372 {
373 exfat_error("invalid cluster 0x%x while writing", cluster);
374 return -1;
375 }
376 lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
377 exfat_pwrite(ef->dev, bufp, lsize, exfat_c2o(ef, cluster) + loffset);
378 bufp += lsize;
379 loffset = 0;
380 remainder -= lsize;
381 cluster = exfat_next_cluster(ef, node, cluster);
382 }
383 exfat_update_mtime(node);
384 return size - remainder;
385}