1 | /* |
---|
2 | * fat_fat_operations.c |
---|
3 | * |
---|
4 | * General operations on File Allocation Table |
---|
5 | * |
---|
6 | * Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia |
---|
7 | * Author: Eugeny S. Mints <Eugeny.Mints@oktet.ru> |
---|
8 | * |
---|
9 | * @(#) $Id$ |
---|
10 | */ |
---|
11 | |
---|
12 | #if HAVE_CONFIG_H |
---|
13 | #include "config.h" |
---|
14 | #endif |
---|
15 | |
---|
16 | #include <sys/types.h> |
---|
17 | #include <sys/stat.h> |
---|
18 | #include <fcntl.h> |
---|
19 | #include <unistd.h> |
---|
20 | #include <errno.h> |
---|
21 | #include <stdlib.h> |
---|
22 | #include <assert.h> |
---|
23 | |
---|
24 | #include <rtems/libio_.h> |
---|
25 | |
---|
26 | #include "fat.h" |
---|
27 | #include "fat_fat_operations.h" |
---|
28 | |
---|
29 | /* fat_scan_fat_for_free_clusters -- |
---|
30 | * Allocate chain of free clusters from Files Allocation Table |
---|
31 | * |
---|
32 | * PARAMETERS: |
---|
33 | * mt_entry - mount table entry |
---|
34 | * chain - the number of the first allocated cluster (first cluster |
---|
35 | * in the chain) |
---|
36 | * count - count of clusters to allocate (chain length) |
---|
37 | * |
---|
38 | * RETURNS: |
---|
39 | * RC_OK on success, or error code if error occured (errno set |
---|
40 | * appropriately) |
---|
41 | * |
---|
42 | * |
---|
43 | */ |
---|
44 | int |
---|
45 | fat_scan_fat_for_free_clusters( |
---|
46 | rtems_filesystem_mount_table_entry_t *mt_entry, |
---|
47 | uint32_t *chain, |
---|
48 | uint32_t count, |
---|
49 | uint32_t *cls_added, |
---|
50 | uint32_t *last_cl |
---|
51 | ) |
---|
52 | { |
---|
53 | int rc = RC_OK; |
---|
54 | fat_fs_info_t *fs_info = mt_entry->fs_info; |
---|
55 | uint32_t cl4find = 2; |
---|
56 | uint32_t next_cln = 0; |
---|
57 | uint32_t save_cln = 0; |
---|
58 | uint32_t data_cls_val = fs_info->vol.data_cls + 2; |
---|
59 | uint32_t i = 2; |
---|
60 | |
---|
61 | *cls_added = 0; |
---|
62 | |
---|
63 | if (count == 0) |
---|
64 | return rc; |
---|
65 | |
---|
66 | if (fs_info->vol.next_cl != FAT_UNDEFINED_VALUE) |
---|
67 | cl4find = fs_info->vol.next_cl; |
---|
68 | |
---|
69 | /* |
---|
70 | * fs_info->vol.data_cls is exactly the count of data clusters |
---|
71 | * starting at cluster 2, so the maximum valid cluster number is |
---|
72 | * (fs_info->vol.data_cls + 1) |
---|
73 | */ |
---|
74 | while (i < data_cls_val) |
---|
75 | { |
---|
76 | rc = fat_get_fat_cluster(mt_entry, cl4find, &next_cln); |
---|
77 | if ( rc != RC_OK ) |
---|
78 | { |
---|
79 | if (*cls_added != 0) |
---|
80 | fat_free_fat_clusters_chain(mt_entry, (*chain)); |
---|
81 | return rc; |
---|
82 | } |
---|
83 | |
---|
84 | if (next_cln == FAT_GENFAT_FREE) |
---|
85 | { |
---|
86 | /* |
---|
87 | * We are enforced to process allocation of the first free cluster |
---|
88 | * by separate 'if' statement because otherwise undo function |
---|
89 | * wouldn't work properly |
---|
90 | */ |
---|
91 | if (*cls_added == 0) |
---|
92 | { |
---|
93 | *chain = cl4find; |
---|
94 | rc = fat_set_fat_cluster(mt_entry, cl4find, FAT_GENFAT_EOC); |
---|
95 | if ( rc != RC_OK ) |
---|
96 | { |
---|
97 | /* |
---|
98 | * this is the first cluster we tried to allocate so no |
---|
99 | * cleanup activity needed |
---|
100 | */ |
---|
101 | return rc; |
---|
102 | } |
---|
103 | } |
---|
104 | else |
---|
105 | { |
---|
106 | /* set EOC value to new allocated cluster */ |
---|
107 | rc = fat_set_fat_cluster(mt_entry, cl4find, FAT_GENFAT_EOC); |
---|
108 | if ( rc != RC_OK ) |
---|
109 | { |
---|
110 | /* cleanup activity */ |
---|
111 | fat_free_fat_clusters_chain(mt_entry, (*chain)); |
---|
112 | return rc; |
---|
113 | } |
---|
114 | |
---|
115 | rc = fat_set_fat_cluster(mt_entry, save_cln, cl4find); |
---|
116 | if ( rc != RC_OK ) |
---|
117 | { |
---|
118 | /* cleanup activity */ |
---|
119 | fat_free_fat_clusters_chain(mt_entry, (*chain)); |
---|
120 | /* trying to save last allocated cluster for future use */ |
---|
121 | fat_set_fat_cluster(mt_entry, cl4find, FAT_GENFAT_FREE); |
---|
122 | fat_buf_release(fs_info); |
---|
123 | return rc; |
---|
124 | } |
---|
125 | } |
---|
126 | |
---|
127 | save_cln = cl4find; |
---|
128 | (*cls_added)++; |
---|
129 | |
---|
130 | /* have we satisfied request ? */ |
---|
131 | if (*cls_added == count) |
---|
132 | { |
---|
133 | fs_info->vol.next_cl = save_cln; |
---|
134 | if (fs_info->vol.free_cls != 0xFFFFFFFF) |
---|
135 | fs_info->vol.free_cls -= (*cls_added); |
---|
136 | *last_cl = save_cln; |
---|
137 | fat_buf_release(fs_info); |
---|
138 | return rc; |
---|
139 | } |
---|
140 | } |
---|
141 | i++; |
---|
142 | cl4find++; |
---|
143 | if (cl4find >= data_cls_val) |
---|
144 | cl4find = 2; |
---|
145 | } |
---|
146 | |
---|
147 | fs_info->vol.next_cl = save_cln; |
---|
148 | if (fs_info->vol.free_cls != 0xFFFFFFFF) |
---|
149 | fs_info->vol.free_cls -= (*cls_added); |
---|
150 | |
---|
151 | *last_cl = save_cln; |
---|
152 | fat_buf_release(fs_info); |
---|
153 | return RC_OK; |
---|
154 | } |
---|
155 | |
---|
156 | /* fat_free_fat_clusters_chain -- |
---|
157 | * Free chain of clusters in Files Allocation Table. |
---|
158 | * |
---|
159 | * PARAMETERS: |
---|
160 | * mt_entry - mount table entry |
---|
161 | * chain - number of the first cluster in the chain |
---|
162 | * |
---|
163 | * RETURNS: |
---|
164 | * RC_OK on success, or -1 if error occured (errno set appropriately) |
---|
165 | */ |
---|
166 | int |
---|
167 | fat_free_fat_clusters_chain( |
---|
168 | rtems_filesystem_mount_table_entry_t *mt_entry, |
---|
169 | uint32_t chain |
---|
170 | ) |
---|
171 | { |
---|
172 | int rc = RC_OK, rc1 = RC_OK; |
---|
173 | fat_fs_info_t *fs_info = mt_entry->fs_info; |
---|
174 | uint32_t cur_cln = chain; |
---|
175 | uint32_t next_cln = 0; |
---|
176 | uint32_t freed_cls_cnt = 0; |
---|
177 | |
---|
178 | while ((cur_cln & fs_info->vol.mask) < fs_info->vol.eoc_val) |
---|
179 | { |
---|
180 | rc = fat_get_fat_cluster(mt_entry, cur_cln, &next_cln); |
---|
181 | if ( rc != RC_OK ) |
---|
182 | { |
---|
183 | if(fs_info->vol.free_cls != FAT_UNDEFINED_VALUE) |
---|
184 | fs_info->vol.free_cls += freed_cls_cnt; |
---|
185 | |
---|
186 | fat_buf_release(fs_info); |
---|
187 | return rc; |
---|
188 | } |
---|
189 | |
---|
190 | rc = fat_set_fat_cluster(mt_entry, cur_cln, FAT_GENFAT_FREE); |
---|
191 | if ( rc != RC_OK ) |
---|
192 | rc1 = rc; |
---|
193 | |
---|
194 | freed_cls_cnt++; |
---|
195 | cur_cln = next_cln; |
---|
196 | } |
---|
197 | |
---|
198 | fs_info->vol.next_cl = chain; |
---|
199 | if (fs_info->vol.free_cls != FAT_UNDEFINED_VALUE) |
---|
200 | fs_info->vol.free_cls += freed_cls_cnt; |
---|
201 | |
---|
202 | fat_buf_release(fs_info); |
---|
203 | if (rc1 != RC_OK) |
---|
204 | return rc1; |
---|
205 | |
---|
206 | return RC_OK; |
---|
207 | } |
---|
208 | |
---|
209 | /* fat_get_fat_cluster -- |
---|
210 | * Fetches the contents of the cluster (link to next cluster in the chain) |
---|
211 | * from Files Allocation Table. |
---|
212 | * |
---|
213 | * PARAMETERS: |
---|
214 | * mt_entry - mount table entry |
---|
215 | * cln - number of cluster to fetch the contents from |
---|
216 | * ret_val - contents of the cluster 'cln' (link to next cluster in |
---|
217 | * the chain) |
---|
218 | * |
---|
219 | * RETURNS: |
---|
220 | * RC_OK on success, or -1 if error occured |
---|
221 | * and errno set appropriately |
---|
222 | */ |
---|
223 | int |
---|
224 | fat_get_fat_cluster( |
---|
225 | rtems_filesystem_mount_table_entry_t *mt_entry, |
---|
226 | uint32_t cln, |
---|
227 | uint32_t *ret_val |
---|
228 | ) |
---|
229 | { |
---|
230 | int rc = RC_OK; |
---|
231 | register fat_fs_info_t *fs_info = mt_entry->fs_info; |
---|
232 | bdbuf_buffer *block0 = NULL; |
---|
233 | uint32_t sec = 0; |
---|
234 | uint32_t ofs = 0; |
---|
235 | |
---|
236 | /* sanity check */ |
---|
237 | if ( (cln < 2) || (cln > (fs_info->vol.data_cls + 1)) ) |
---|
238 | set_errno_and_return_minus_one(EIO); |
---|
239 | |
---|
240 | sec = (FAT_FAT_OFFSET(fs_info->vol.type, cln) >> fs_info->vol.sec_log2) + |
---|
241 | fs_info->vol.afat_loc; |
---|
242 | ofs = FAT_FAT_OFFSET(fs_info->vol.type, cln) & (fs_info->vol.bps - 1); |
---|
243 | |
---|
244 | rc = fat_buf_access(fs_info, sec, FAT_OP_TYPE_READ, &block0); |
---|
245 | if (rc != RC_OK) |
---|
246 | return rc; |
---|
247 | |
---|
248 | switch ( fs_info->vol.type ) |
---|
249 | { |
---|
250 | case FAT_FAT12: |
---|
251 | /* |
---|
252 | * we are enforced in complex computations for FAT12 to escape CPU |
---|
253 | * align problems for some architectures |
---|
254 | */ |
---|
255 | *ret_val = (*((uint8_t *)(block0->buffer + ofs))); |
---|
256 | if ( ofs == (fs_info->vol.bps - 1) ) |
---|
257 | { |
---|
258 | rc = fat_buf_access(fs_info, sec + 1, FAT_OP_TYPE_READ, |
---|
259 | &block0); |
---|
260 | if (rc != RC_OK) |
---|
261 | return rc; |
---|
262 | |
---|
263 | *ret_val |= (*((uint8_t *)(block0->buffer)))<<8; |
---|
264 | } |
---|
265 | else |
---|
266 | { |
---|
267 | *ret_val |= (*((uint8_t *)(block0->buffer + ofs + 1)))<<8; |
---|
268 | } |
---|
269 | |
---|
270 | if ( FAT_CLUSTER_IS_ODD(cln) ) |
---|
271 | *ret_val = (*ret_val) >> FAT12_SHIFT; |
---|
272 | else |
---|
273 | *ret_val = (*ret_val) & FAT_FAT12_MASK; |
---|
274 | break; |
---|
275 | |
---|
276 | case FAT_FAT16: |
---|
277 | *ret_val = *((uint16_t *)(block0->buffer + ofs)); |
---|
278 | *ret_val = CF_LE_W(*ret_val); |
---|
279 | break; |
---|
280 | |
---|
281 | case FAT_FAT32: |
---|
282 | *ret_val = *((uint32_t *)(block0->buffer + ofs)); |
---|
283 | *ret_val = CF_LE_L(*ret_val); |
---|
284 | break; |
---|
285 | |
---|
286 | default: |
---|
287 | set_errno_and_return_minus_one(EIO); |
---|
288 | break; |
---|
289 | } |
---|
290 | |
---|
291 | return RC_OK; |
---|
292 | } |
---|
293 | |
---|
294 | /* fat_set_fat_cluster -- |
---|
295 | * Set the contents of the cluster (link to next cluster in the chain) |
---|
296 | * from Files Allocation Table. |
---|
297 | * |
---|
298 | * PARAMETERS: |
---|
299 | * mt_entry - mount table entry |
---|
300 | * cln - number of cluster to set contents to |
---|
301 | * in_val - value to set |
---|
302 | * |
---|
303 | * RETURNS: |
---|
304 | * RC_OK on success, or -1 if error occured |
---|
305 | * and errno set appropriately |
---|
306 | */ |
---|
307 | int |
---|
308 | fat_set_fat_cluster( |
---|
309 | rtems_filesystem_mount_table_entry_t *mt_entry, |
---|
310 | uint32_t cln, |
---|
311 | uint32_t in_val |
---|
312 | ) |
---|
313 | { |
---|
314 | int rc = RC_OK; |
---|
315 | fat_fs_info_t *fs_info = mt_entry->fs_info; |
---|
316 | uint32_t sec = 0; |
---|
317 | uint32_t ofs = 0; |
---|
318 | uint16_t fat16_clv = 0; |
---|
319 | uint32_t fat32_clv = 0; |
---|
320 | bdbuf_buffer *block0 = NULL; |
---|
321 | |
---|
322 | /* sanity check */ |
---|
323 | if ( (cln < 2) || (cln > (fs_info->vol.data_cls + 1)) ) |
---|
324 | set_errno_and_return_minus_one(EIO); |
---|
325 | |
---|
326 | sec = (FAT_FAT_OFFSET(fs_info->vol.type, cln) >> fs_info->vol.sec_log2) + |
---|
327 | fs_info->vol.afat_loc; |
---|
328 | ofs = FAT_FAT_OFFSET(fs_info->vol.type, cln) & (fs_info->vol.bps - 1); |
---|
329 | |
---|
330 | rc = fat_buf_access(fs_info, sec, FAT_OP_TYPE_READ, &block0); |
---|
331 | if (rc != RC_OK) |
---|
332 | return rc; |
---|
333 | |
---|
334 | switch ( fs_info->vol.type ) |
---|
335 | { |
---|
336 | case FAT_FAT12: |
---|
337 | if ( FAT_CLUSTER_IS_ODD(cln) ) |
---|
338 | { |
---|
339 | fat16_clv = ((uint16_t )in_val) << FAT_FAT12_SHIFT; |
---|
340 | *((uint8_t *)(block0->buffer + ofs)) = |
---|
341 | (*((uint8_t *)(block0->buffer + ofs))) & 0x0F; |
---|
342 | |
---|
343 | *((uint8_t *)(block0->buffer + ofs)) = |
---|
344 | (*((uint8_t *)(block0->buffer + ofs))) | |
---|
345 | (uint8_t )(fat16_clv & 0x00FF); |
---|
346 | |
---|
347 | fat_buf_mark_modified(fs_info); |
---|
348 | |
---|
349 | if ( ofs == (fs_info->vol.bps - 1) ) |
---|
350 | { |
---|
351 | rc = fat_buf_access(fs_info, sec + 1, FAT_OP_TYPE_READ, |
---|
352 | &block0); |
---|
353 | if (rc != RC_OK) |
---|
354 | return rc; |
---|
355 | |
---|
356 | *((uint8_t *)(block0->buffer)) &= 0x00; |
---|
357 | |
---|
358 | *((uint8_t *)(block0->buffer)) = |
---|
359 | (*((uint8_t *)(block0->buffer))) | |
---|
360 | (uint8_t )((fat16_clv & 0xFF00)>>8); |
---|
361 | |
---|
362 | fat_buf_mark_modified(fs_info); |
---|
363 | } |
---|
364 | else |
---|
365 | { |
---|
366 | *((uint8_t *)(block0->buffer + ofs + 1)) &= 0x00; |
---|
367 | |
---|
368 | *((uint8_t *)(block0->buffer + ofs + 1)) = |
---|
369 | (*((uint8_t *)(block0->buffer + ofs + 1))) | |
---|
370 | (uint8_t )((fat16_clv & 0xFF00)>>8); |
---|
371 | } |
---|
372 | } |
---|
373 | else |
---|
374 | { |
---|
375 | fat16_clv = ((uint16_t )in_val) & FAT_FAT12_MASK; |
---|
376 | *((uint8_t *)(block0->buffer + ofs)) &= 0x00; |
---|
377 | |
---|
378 | *((uint8_t *)(block0->buffer + ofs)) = |
---|
379 | (*((uint8_t *)(block0->buffer + ofs))) | |
---|
380 | (uint8_t )(fat16_clv & 0x00FF); |
---|
381 | |
---|
382 | fat_buf_mark_modified(fs_info); |
---|
383 | |
---|
384 | if ( ofs == (fs_info->vol.bps - 1) ) |
---|
385 | { |
---|
386 | rc = fat_buf_access(fs_info, sec + 1, FAT_OP_TYPE_READ, |
---|
387 | &block0); |
---|
388 | if (rc != RC_OK) |
---|
389 | return rc; |
---|
390 | |
---|
391 | *((uint8_t *)(block0->buffer)) = |
---|
392 | (*((uint8_t *)(block0->buffer))) & 0xF0; |
---|
393 | |
---|
394 | *((uint8_t *)(block0->buffer)) = |
---|
395 | (*((uint8_t *)(block0->buffer))) | |
---|
396 | (uint8_t )((fat16_clv & 0xFF00)>>8); |
---|
397 | |
---|
398 | fat_buf_mark_modified(fs_info); |
---|
399 | } |
---|
400 | else |
---|
401 | { |
---|
402 | *((uint8_t *)(block0->buffer + ofs + 1)) = |
---|
403 | (*((uint8_t *)(block0->buffer + ofs + 1))) & 0xF0; |
---|
404 | |
---|
405 | *((uint8_t *)(block0->buffer + ofs+1)) = |
---|
406 | (*((uint8_t *)(block0->buffer + ofs+1))) | |
---|
407 | (uint8_t )((fat16_clv & 0xFF00)>>8); |
---|
408 | } |
---|
409 | } |
---|
410 | break; |
---|
411 | |
---|
412 | case FAT_FAT16: |
---|
413 | *((uint16_t *)(block0->buffer + ofs)) = |
---|
414 | (uint16_t )(CT_LE_W(in_val)); |
---|
415 | fat_buf_mark_modified(fs_info); |
---|
416 | break; |
---|
417 | |
---|
418 | case FAT_FAT32: |
---|
419 | fat32_clv = CT_LE_L((in_val & FAT_FAT32_MASK)); |
---|
420 | |
---|
421 | *((uint32_t *)(block0->buffer + ofs)) = |
---|
422 | (*((uint32_t *)(block0->buffer + ofs))) & (CT_LE_L(0xF0000000)); |
---|
423 | |
---|
424 | *((uint32_t *)(block0->buffer + ofs)) = |
---|
425 | fat32_clv | (*((uint32_t *)(block0->buffer + ofs))); |
---|
426 | |
---|
427 | fat_buf_mark_modified(fs_info); |
---|
428 | break; |
---|
429 | |
---|
430 | default: |
---|
431 | set_errno_and_return_minus_one(EIO); |
---|
432 | break; |
---|
433 | |
---|
434 | } |
---|
435 | |
---|
436 | return RC_OK; |
---|
437 | } |
---|