4 * R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
6 * SPDX-License-Identifier: GPL-2.0+
13 #include <asm/byteorder.h>
15 #include <linux/ctype.h>
17 #include <linux/math64.h>
20 static void uppercase(char *str
, int len
)
24 for (i
= 0; i
< len
; i
++) {
30 static int total_sector
;
31 static int disk_write(__u32 block
, __u32 nr_blocks
, void *buf
)
38 if (cur_part_info
.start
+ block
+ nr_blocks
>
39 cur_part_info
.start
+ total_sector
) {
40 printf("error: overflow occurs\n");
44 ret
= blk_dwrite(cur_dev
, cur_part_info
.start
+ block
, nr_blocks
, buf
);
45 if (nr_blocks
&& ret
== 0)
52 * Set short name in directory entry
54 static void set_name(dir_entry
*dirent
, const char *filename
)
56 char s_name
[VFAT_MAXLEN_BYTES
];
58 int period_location
, len
, i
, ext_num
;
63 len
= strlen(filename
);
67 strcpy(s_name
, filename
);
68 uppercase(s_name
, len
);
70 period
= strchr(s_name
, '.');
72 period_location
= len
;
75 period_location
= period
- s_name
;
76 ext_num
= len
- period_location
- 1;
79 /* Pad spaces when the length of file name is shorter than eight */
80 if (period_location
< 8) {
81 memcpy(dirent
->name
, s_name
, period_location
);
82 for (i
= period_location
; i
< 8; i
++)
83 dirent
->name
[i
] = ' ';
84 } else if (period_location
== 8) {
85 memcpy(dirent
->name
, s_name
, period_location
);
87 memcpy(dirent
->name
, s_name
, 6);
88 dirent
->name
[6] = '~';
89 dirent
->name
[7] = '1';
93 memcpy(dirent
->ext
, s_name
+ period_location
+ 1, ext_num
);
94 for (i
= ext_num
; i
< 3; i
++)
97 memcpy(dirent
->ext
, s_name
+ period_location
+ 1, 3);
99 debug("name : %s\n", dirent
->name
);
100 debug("ext : %s\n", dirent
->ext
);
103 static __u8 num_of_fats
;
105 * Write fat buffer into block device
107 static int flush_dirty_fat_buffer(fsdata
*mydata
)
109 int getsize
= FATBUFBLOCKS
;
110 __u32 fatlength
= mydata
->fatlength
;
111 __u8
*bufptr
= mydata
->fatbuf
;
112 __u32 startblock
= mydata
->fatbufnum
* FATBUFBLOCKS
;
114 debug("debug: evicting %d, dirty: %d\n", mydata
->fatbufnum
,
115 (int)mydata
->fat_dirty
);
117 if ((!mydata
->fat_dirty
) || (mydata
->fatbufnum
== -1))
120 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
121 if (startblock
+ getsize
> fatlength
)
122 getsize
= fatlength
- startblock
;
124 startblock
+= mydata
->fat_sect
;
127 if (disk_write(startblock
, getsize
, bufptr
) < 0) {
128 debug("error: writing FAT blocks\n");
132 if (num_of_fats
== 2) {
133 /* Update corresponding second FAT blocks */
134 startblock
+= mydata
->fatlength
;
135 if (disk_write(startblock
, getsize
, bufptr
) < 0) {
136 debug("error: writing second FAT blocks\n");
140 mydata
->fat_dirty
= 0;
146 * Set the file name information from 'name' into 'slotptr',
148 static int str2slot(dir_slot
*slotptr
, const char *name
, int *idx
)
152 for (j
= 0; j
<= 8; j
+= 2) {
153 if (name
[*idx
] == 0x00) {
154 slotptr
->name0_4
[j
] = 0;
155 slotptr
->name0_4
[j
+ 1] = 0;
159 slotptr
->name0_4
[j
] = name
[*idx
];
163 for (j
= 0; j
<= 10; j
+= 2) {
164 if (name
[*idx
] == 0x00) {
165 slotptr
->name5_10
[j
] = 0;
166 slotptr
->name5_10
[j
+ 1] = 0;
170 slotptr
->name5_10
[j
] = name
[*idx
];
174 for (j
= 0; j
<= 2; j
+= 2) {
175 if (name
[*idx
] == 0x00) {
176 slotptr
->name11_12
[j
] = 0;
177 slotptr
->name11_12
[j
+ 1] = 0;
181 slotptr
->name11_12
[j
] = name
[*idx
];
186 if (name
[*idx
] == 0x00)
190 /* Not used characters are filled with 0xff 0xff */
192 for (; end_idx
< 5; end_idx
++) {
193 slotptr
->name0_4
[end_idx
* 2] = 0xff;
194 slotptr
->name0_4
[end_idx
* 2 + 1] = 0xff;
199 for (; end_idx
< 6; end_idx
++) {
200 slotptr
->name5_10
[end_idx
* 2] = 0xff;
201 slotptr
->name5_10
[end_idx
* 2 + 1] = 0xff;
206 for (; end_idx
< 2; end_idx
++) {
207 slotptr
->name11_12
[end_idx
* 2] = 0xff;
208 slotptr
->name11_12
[end_idx
* 2 + 1] = 0xff;
214 static int is_next_clust(fsdata
*mydata
, dir_entry
*dentptr
);
215 static void flush_dir_table(fsdata
*mydata
, dir_entry
**dentptr
);
218 * Fill dir_slot entries with appropriate name, id, and attr
219 * The real directory entry is returned by 'dentptr'
222 fill_dir_slot(fsdata
*mydata
, dir_entry
**dentptr
, const char *l_name
)
224 __u8 temp_dir_slot_buffer
[MAX_LFN_SLOT
* sizeof(dir_slot
)];
225 dir_slot
*slotptr
= (dir_slot
*)temp_dir_slot_buffer
;
226 __u8 counter
= 0, checksum
;
229 /* Get short file name checksum value */
230 checksum
= mkcksum((*dentptr
)->name
, (*dentptr
)->ext
);
233 memset(slotptr
, 0x00, sizeof(dir_slot
));
234 ret
= str2slot(slotptr
, l_name
, &idx
);
235 slotptr
->id
= ++counter
;
236 slotptr
->attr
= ATTR_VFAT
;
237 slotptr
->alias_checksum
= checksum
;
242 slotptr
->id
|= LAST_LONG_ENTRY_MASK
;
244 while (counter
>= 1) {
245 if (is_next_clust(mydata
, *dentptr
)) {
246 /* A new cluster is allocated for directory table */
247 flush_dir_table(mydata
, dentptr
);
249 memcpy(*dentptr
, slotptr
, sizeof(dir_slot
));
255 if (is_next_clust(mydata
, *dentptr
)) {
256 /* A new cluster is allocated for directory table */
257 flush_dir_table(mydata
, dentptr
);
261 static __u32 dir_curclust
;
264 * Extract the full long filename starting at 'retdent' (which is really
265 * a slot) into 'l_name'. If successful also copy the real directory entry
267 * If additional adjacent cluster for directory entries is read into memory,
268 * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
269 * the location of the real directory entry is returned by 'retdent'
270 * Return 0 on success, -1 otherwise.
273 get_long_file_name(fsdata
*mydata
, int curclust
, __u8
*cluster
,
274 dir_entry
**retdent
, char *l_name
)
277 dir_slot
*slotptr
= (dir_slot
*)(*retdent
);
278 dir_slot
*slotptr2
= NULL
;
279 __u8
*buflimit
= cluster
+ mydata
->sect_size
* ((curclust
== 0) ?
282 __u8 counter
= (slotptr
->id
& ~LAST_LONG_ENTRY_MASK
) & 0xff;
283 int idx
= 0, cur_position
= 0;
285 if (counter
> VFAT_MAXSEQ
) {
286 debug("Error: VFAT name is too long\n");
290 while ((__u8
*)slotptr
< buflimit
) {
293 if (((slotptr
->id
& ~LAST_LONG_ENTRY_MASK
) & 0xff) != counter
)
299 if ((__u8
*)slotptr
>= buflimit
) {
302 curclust
= get_fatent(mydata
, dir_curclust
);
303 if (CHECK_CLUST(curclust
, mydata
->fatsize
)) {
304 debug("curclust: 0x%x\n", curclust
);
305 printf("Invalid FAT entry\n");
309 dir_curclust
= curclust
;
311 if (get_cluster(mydata
, curclust
, get_contents_vfatname_block
,
312 mydata
->clust_size
* mydata
->sect_size
) != 0) {
313 debug("Error: reading directory block\n");
317 slotptr2
= (dir_slot
*)get_contents_vfatname_block
;
318 while (counter
> 0) {
319 if (((slotptr2
->id
& ~LAST_LONG_ENTRY_MASK
)
326 /* Save the real directory entry */
327 realdent
= (dir_entry
*)slotptr2
;
328 while ((__u8
*)slotptr2
> get_contents_vfatname_block
) {
330 slot2str(slotptr2
, l_name
, &idx
);
333 /* Save the real directory entry */
334 realdent
= (dir_entry
*)slotptr
;
339 if (slot2str(slotptr
, l_name
, &idx
))
341 } while (!(slotptr
->id
& LAST_LONG_ENTRY_MASK
));
344 if (*l_name
== DELETED_FLAG
)
346 else if (*l_name
== aRING
)
347 *l_name
= DELETED_FLAG
;
348 downcase(l_name
, INT_MAX
);
350 /* Return the real directory entry */
354 memcpy(get_dentfromdir_block
, get_contents_vfatname_block
,
355 mydata
->clust_size
* mydata
->sect_size
);
356 cur_position
= (__u8
*)realdent
- get_contents_vfatname_block
;
357 *retdent
= (dir_entry
*) &get_dentfromdir_block
[cur_position
];
364 * Set the entry at index 'entry' in a FAT (12/16/32) table.
366 static int set_fatent_value(fsdata
*mydata
, __u32 entry
, __u32 entry_value
)
368 __u32 bufnum
, offset
, off16
;
371 switch (mydata
->fatsize
) {
373 bufnum
= entry
/ FAT32BUFSIZE
;
374 offset
= entry
- bufnum
* FAT32BUFSIZE
;
377 bufnum
= entry
/ FAT16BUFSIZE
;
378 offset
= entry
- bufnum
* FAT16BUFSIZE
;
381 bufnum
= entry
/ FAT12BUFSIZE
;
382 offset
= entry
- bufnum
* FAT12BUFSIZE
;
385 /* Unsupported FAT size */
389 /* Read a new block of FAT entries into the cache. */
390 if (bufnum
!= mydata
->fatbufnum
) {
391 int getsize
= FATBUFBLOCKS
;
392 __u8
*bufptr
= mydata
->fatbuf
;
393 __u32 fatlength
= mydata
->fatlength
;
394 __u32 startblock
= bufnum
* FATBUFBLOCKS
;
396 /* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
397 if (startblock
+ getsize
> fatlength
)
398 getsize
= fatlength
- startblock
;
400 if (flush_dirty_fat_buffer(mydata
) < 0)
403 startblock
+= mydata
->fat_sect
;
405 if (disk_read(startblock
, getsize
, bufptr
) < 0) {
406 debug("Error reading FAT blocks\n");
409 mydata
->fatbufnum
= bufnum
;
413 mydata
->fat_dirty
= 1;
415 /* Set the actual entry */
416 switch (mydata
->fatsize
) {
418 ((__u32
*) mydata
->fatbuf
)[offset
] = cpu_to_le32(entry_value
);
421 ((__u16
*) mydata
->fatbuf
)[offset
] = cpu_to_le16(entry_value
);
424 off16
= (offset
* 3) / 4;
426 switch (offset
& 0x3) {
428 val1
= cpu_to_le16(entry_value
) & 0xfff;
429 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xfff;
430 ((__u16
*)mydata
->fatbuf
)[off16
] |= val1
;
433 val1
= cpu_to_le16(entry_value
) & 0xf;
434 val2
= (cpu_to_le16(entry_value
) >> 4) & 0xff;
436 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xf000;
437 ((__u16
*)mydata
->fatbuf
)[off16
] |= (val1
<< 12);
439 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] &= ~0xff;
440 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] |= val2
;
443 val1
= cpu_to_le16(entry_value
) & 0xff;
444 val2
= (cpu_to_le16(entry_value
) >> 8) & 0xf;
446 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xff00;
447 ((__u16
*)mydata
->fatbuf
)[off16
] |= (val1
<< 8);
449 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] &= ~0xf;
450 ((__u16
*)mydata
->fatbuf
)[off16
+ 1] |= val2
;
453 val1
= cpu_to_le16(entry_value
) & 0xfff;
454 ((__u16
*)mydata
->fatbuf
)[off16
] &= ~0xfff0;
455 ((__u16
*)mydata
->fatbuf
)[off16
] |= (val1
<< 4);
470 * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
471 * and link it to 'entry'. EOC marker is not set on returned entry.
473 static __u32
determine_fatent(fsdata
*mydata
, __u32 entry
)
475 __u32 next_fat
, next_entry
= entry
+ 1;
478 next_fat
= get_fatent(mydata
, next_entry
);
480 /* found free entry, link to entry */
481 set_fatent_value(mydata
, entry
, next_entry
);
486 debug("FAT%d: entry: %08x, entry_value: %04x\n",
487 mydata
->fatsize
, entry
, next_entry
);
493 * Write at most 'size' bytes from 'buffer' into the specified cluster.
494 * Return 0 on success, -1 otherwise.
497 set_cluster(fsdata
*mydata
, __u32 clustnum
, __u8
*buffer
,
505 startsect
= clust_to_sect(mydata
, clustnum
);
507 startsect
= mydata
->rootdir_sect
;
509 debug("clustnum: %d, startsect: %d\n", clustnum
, startsect
);
511 if ((unsigned long)buffer
& (ARCH_DMA_MINALIGN
- 1)) {
512 ALLOC_CACHE_ALIGN_BUFFER(__u8
, tmpbuf
, mydata
->sect_size
);
514 printf("FAT: Misaligned buffer address (%p)\n", buffer
);
516 while (size
>= mydata
->sect_size
) {
517 memcpy(tmpbuf
, buffer
, mydata
->sect_size
);
518 ret
= disk_write(startsect
++, 1, tmpbuf
);
520 debug("Error writing data (got %d)\n", ret
);
524 buffer
+= mydata
->sect_size
;
525 size
-= mydata
->sect_size
;
527 } else if (size
>= mydata
->sect_size
) {
528 idx
= size
/ mydata
->sect_size
;
529 ret
= disk_write(startsect
, idx
, buffer
);
531 debug("Error writing data (got %d)\n", ret
);
536 idx
*= mydata
->sect_size
;
542 ALLOC_CACHE_ALIGN_BUFFER(__u8
, tmpbuf
, mydata
->sect_size
);
544 memcpy(tmpbuf
, buffer
, size
);
545 ret
= disk_write(startsect
, 1, tmpbuf
);
547 debug("Error writing data (got %d)\n", ret
);
556 * Find the first empty cluster
558 static int find_empty_cluster(fsdata
*mydata
)
560 __u32 fat_val
, entry
= 3;
563 fat_val
= get_fatent(mydata
, entry
);
573 * Write directory entries in 'get_dentfromdir_block' to block device
575 static void flush_dir_table(fsdata
*mydata
, dir_entry
**dentptr
)
577 int dir_newclust
= 0;
579 if (set_cluster(mydata
, dir_curclust
,
580 get_dentfromdir_block
,
581 mydata
->clust_size
* mydata
->sect_size
) != 0) {
582 printf("error: wrinting directory entry\n");
585 dir_newclust
= find_empty_cluster(mydata
);
586 set_fatent_value(mydata
, dir_curclust
, dir_newclust
);
587 if (mydata
->fatsize
== 32)
588 set_fatent_value(mydata
, dir_newclust
, 0xffffff8);
589 else if (mydata
->fatsize
== 16)
590 set_fatent_value(mydata
, dir_newclust
, 0xfff8);
591 else if (mydata
->fatsize
== 12)
592 set_fatent_value(mydata
, dir_newclust
, 0xff8);
594 dir_curclust
= dir_newclust
;
596 if (flush_dirty_fat_buffer(mydata
) < 0)
599 memset(get_dentfromdir_block
, 0x00,
600 mydata
->clust_size
* mydata
->sect_size
);
602 *dentptr
= (dir_entry
*) get_dentfromdir_block
;
606 * Set empty cluster from 'entry' to the end of a file
608 static int clear_fatent(fsdata
*mydata
, __u32 entry
)
612 while (!CHECK_CLUST(entry
, mydata
->fatsize
)) {
613 fat_val
= get_fatent(mydata
, entry
);
615 set_fatent_value(mydata
, entry
, 0);
622 /* Flush fat buffer */
623 if (flush_dirty_fat_buffer(mydata
) < 0)
630 * Write at most 'maxsize' bytes from 'buffer' into
631 * the file associated with 'dentptr'
632 * Update the number of bytes written in *gotsize and return 0
633 * or return -1 on fatal errors.
636 set_contents(fsdata
*mydata
, dir_entry
*dentptr
, __u8
*buffer
,
637 loff_t maxsize
, loff_t
*gotsize
)
639 loff_t filesize
= FAT2CPU32(dentptr
->size
);
640 unsigned int bytesperclust
= mydata
->clust_size
* mydata
->sect_size
;
641 __u32 curclust
= START(dentptr
);
642 __u32 endclust
= 0, newclust
= 0;
646 debug("Filesize: %llu bytes\n", filesize
);
648 if (maxsize
> 0 && filesize
> maxsize
)
651 debug("%llu bytes\n", filesize
);
655 debug("error: nonempty clusterless file!\n");
661 actsize
= bytesperclust
;
664 /* search for consecutive clusters */
665 while (actsize
< filesize
) {
666 newclust
= determine_fatent(mydata
, endclust
);
668 if ((newclust
- 1) != endclust
)
671 if (CHECK_CLUST(newclust
, mydata
->fatsize
)) {
672 debug("newclust: 0x%x\n", newclust
);
673 debug("Invalid FAT entry\n");
677 actsize
+= bytesperclust
;
680 /* set remaining bytes */
682 if (set_cluster(mydata
, curclust
, buffer
, (int)actsize
) != 0) {
683 debug("error: writing cluster\n");
688 /* Mark end of file in FAT */
689 if (mydata
->fatsize
== 12)
691 else if (mydata
->fatsize
== 16)
693 else if (mydata
->fatsize
== 32)
694 newclust
= 0xfffffff;
695 set_fatent_value(mydata
, endclust
, newclust
);
699 if (set_cluster(mydata
, curclust
, buffer
, (int)actsize
) != 0) {
700 debug("error: writing cluster\n");
707 if (CHECK_CLUST(newclust
, mydata
->fatsize
)) {
708 debug("newclust: 0x%x\n", newclust
);
709 debug("Invalid FAT entry\n");
712 actsize
= bytesperclust
;
713 curclust
= endclust
= newclust
;
718 * Set start cluster in directory entry
720 static void set_start_cluster(const fsdata
*mydata
, dir_entry
*dentptr
,
723 if (mydata
->fatsize
== 32)
725 cpu_to_le16((start_cluster
& 0xffff0000) >> 16);
726 dentptr
->start
= cpu_to_le16(start_cluster
& 0xffff);
732 static void fill_dentry(fsdata
*mydata
, dir_entry
*dentptr
,
733 const char *filename
, __u32 start_cluster
, __u32 size
, __u8 attr
)
735 set_start_cluster(mydata
, dentptr
, start_cluster
);
736 dentptr
->size
= cpu_to_le32(size
);
738 dentptr
->attr
= attr
;
740 set_name(dentptr
, filename
);
744 * Check whether adding a file makes the file system to
745 * exceed the size of the block device
746 * Return -1 when overflow occurs, otherwise return 0
748 static int check_overflow(fsdata
*mydata
, __u32 clustnum
, loff_t size
)
750 __u32 startsect
, sect_num
, offset
;
753 startsect
= clust_to_sect(mydata
, clustnum
);
755 startsect
= mydata
->rootdir_sect
;
758 sect_num
= div_u64_rem(size
, mydata
->sect_size
, &offset
);
763 if (startsect
+ sect_num
> total_sector
)
769 * Check if adding several entries exceed one cluster boundary
771 static int is_next_clust(fsdata
*mydata
, dir_entry
*dentptr
)
775 cur_position
= (__u8
*)dentptr
- get_dentfromdir_block
;
777 if (cur_position
>= mydata
->clust_size
* mydata
->sect_size
)
783 static dir_entry
*empty_dentptr
;
785 * Find a directory entry based on filename or start cluster number
786 * If the directory entry is not found,
787 * the new position for writing a directory entry will be returned
789 static dir_entry
*find_directory_entry(fsdata
*mydata
, int startsect
,
790 char *filename
, dir_entry
*retdent
, __u32 start
)
792 __u32 curclust
= sect_to_clust(mydata
, startsect
);
794 debug("get_dentfromdir: %s\n", filename
);
801 if (get_cluster(mydata
, curclust
, get_dentfromdir_block
,
802 mydata
->clust_size
* mydata
->sect_size
) != 0) {
803 printf("Error: reading directory block\n");
807 dentptr
= (dir_entry
*)get_dentfromdir_block
;
809 dir_curclust
= curclust
;
811 for (i
= 0; i
< DIRENTSPERCLUST
; i
++) {
812 char s_name
[14], l_name
[VFAT_MAXLEN_BYTES
];
815 if (dentptr
->name
[0] == DELETED_FLAG
) {
817 if (is_next_clust(mydata
, dentptr
))
821 if ((dentptr
->attr
& ATTR_VOLUME
)) {
823 (dentptr
->attr
& ATTR_VFAT
) &&
824 (dentptr
->name
[0] & LAST_LONG_ENTRY_MASK
)) {
825 get_long_file_name(mydata
, curclust
,
826 get_dentfromdir_block
,
828 debug("vfatname: |%s|\n", l_name
);
830 /* Volume label or VFAT entry */
832 if (is_next_clust(mydata
, dentptr
))
837 if (dentptr
->name
[0] == 0) {
838 debug("Dentname == NULL - %d\n", i
);
839 empty_dentptr
= dentptr
;
843 get_name(dentptr
, s_name
);
845 if (strncasecmp(filename
, s_name
, sizeof(s_name
)) &&
846 strncasecmp(filename
, l_name
, sizeof(l_name
))) {
847 debug("Mismatch: |%s|%s|\n",
850 if (is_next_clust(mydata
, dentptr
))
855 memcpy(retdent
, dentptr
, sizeof(dir_entry
));
857 debug("DentName: %s", s_name
);
858 debug(", start: 0x%x", START(dentptr
));
859 debug(", size: 0x%x %s\n",
860 FAT2CPU32(dentptr
->size
),
861 (dentptr
->attr
& ATTR_DIR
) ?
868 * In FAT16/12, the root dir is locate before data area, shows
870 * -------------------------------------------------------------
871 * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
872 * -------------------------------------------------------------
874 * As a result if curclust is in Root dir, it is a negative
878 if (mydata
->fatsize
!= 32 && (int)curclust
<= 1) {
879 /* Current clust is in root dir, set to next clust */
881 if ((int)curclust
<= 1)
882 continue; /* continue to find */
884 /* Reach the end of root dir */
885 empty_dentptr
= dentptr
;
889 curclust
= get_fatent(mydata
, dir_curclust
);
890 if (IS_LAST_CLUST(curclust
, mydata
->fatsize
)) {
891 empty_dentptr
= dentptr
;
894 if (CHECK_CLUST(curclust
, mydata
->fatsize
)) {
895 debug("curclust: 0x%x\n", curclust
);
896 debug("Invalid FAT entry\n");
904 static int do_fat_write(const char *filename
, void *buffer
, loff_t size
,
907 dir_entry
*dentptr
, *retdent
;
913 fsdata
*mydata
= &datablock
;
915 int ret
= -1, name_len
;
916 char l_filename
[VFAT_MAXLEN_BYTES
];
921 if (read_bootsectandvi(&bs
, &volinfo
, &mydata
->fatsize
)) {
922 debug("error: reading boot sector\n");
926 total_sector
= bs
.total_sect
;
927 if (total_sector
== 0)
928 total_sector
= (int)cur_part_info
.size
; /* cast of lbaint_t */
930 if (mydata
->fatsize
== 32)
931 mydata
->fatlength
= bs
.fat32_length
;
933 mydata
->fatlength
= bs
.fat_length
;
935 mydata
->fat_sect
= bs
.reserved
;
937 cursect
= mydata
->rootdir_sect
938 = mydata
->fat_sect
+ mydata
->fatlength
* bs
.fats
;
939 num_of_fats
= bs
.fats
;
941 mydata
->sect_size
= (bs
.sector_size
[1] << 8) + bs
.sector_size
[0];
942 mydata
->clust_size
= bs
.cluster_size
;
944 if (mydata
->fatsize
== 32) {
945 mydata
->data_begin
= mydata
->rootdir_sect
-
946 (mydata
->clust_size
* 2);
950 rootdir_size
= ((bs
.dir_entries
[1] * (int)256 +
954 mydata
->data_begin
= mydata
->rootdir_sect
+
956 (mydata
->clust_size
* 2);
959 mydata
->fatbufnum
= -1;
960 mydata
->fat_dirty
= 0;
961 mydata
->fatbuf
= memalign(ARCH_DMA_MINALIGN
, FATBUFSIZE
);
962 if (mydata
->fatbuf
== NULL
) {
963 debug("Error: allocating memory\n");
967 if (disk_read(cursect
,
968 (mydata
->fatsize
== 32) ?
969 (mydata
->clust_size
) :
970 PREFETCH_BLOCKS
, do_fat_read_at_block
) < 0) {
971 debug("Error: reading rootdir block\n");
974 dentptr
= (dir_entry
*) do_fat_read_at_block
;
976 name_len
= strlen(filename
);
977 if (name_len
>= VFAT_MAXLEN_BYTES
)
978 name_len
= VFAT_MAXLEN_BYTES
- 1;
980 memcpy(l_filename
, filename
, name_len
);
981 l_filename
[name_len
] = 0; /* terminate the string */
982 downcase(l_filename
, INT_MAX
);
984 startsect
= mydata
->rootdir_sect
;
985 retdent
= find_directory_entry(mydata
, startsect
,
986 l_filename
, dentptr
, 0);
988 /* Update file size and start_cluster in a directory entry */
989 retdent
->size
= cpu_to_le32(size
);
990 start_cluster
= START(retdent
);
994 ret
= check_overflow(mydata
, start_cluster
,
997 printf("Error: %llu overflow\n", size
);
1002 ret
= clear_fatent(mydata
, start_cluster
);
1004 printf("Error: clearing FAT entries\n");
1009 set_start_cluster(mydata
, retdent
, 0);
1011 ret
= start_cluster
= find_empty_cluster(mydata
);
1013 printf("Error: finding empty cluster\n");
1017 ret
= check_overflow(mydata
, start_cluster
, size
);
1019 printf("Error: %llu overflow\n", size
);
1023 set_start_cluster(mydata
, retdent
, start_cluster
);
1026 /* Set short name to set alias checksum field in dir_slot */
1027 set_name(empty_dentptr
, filename
);
1028 fill_dir_slot(mydata
, &empty_dentptr
, filename
);
1031 ret
= start_cluster
= find_empty_cluster(mydata
);
1033 printf("Error: finding empty cluster\n");
1037 ret
= check_overflow(mydata
, start_cluster
, size
);
1039 printf("Error: %llu overflow\n", size
);
1046 /* Set attribute as archieve for regular file */
1047 fill_dentry(mydata
, empty_dentptr
, filename
,
1048 start_cluster
, size
, 0x20);
1050 retdent
= empty_dentptr
;
1053 ret
= set_contents(mydata
, retdent
, buffer
, size
, actwrite
);
1055 printf("Error: writing contents\n");
1058 debug("attempt to write 0x%llx bytes\n", *actwrite
);
1060 /* Flush fat buffer */
1061 ret
= flush_dirty_fat_buffer(mydata
);
1063 printf("Error: flush fat buffer\n");
1067 /* Write directory table to device */
1068 ret
= set_cluster(mydata
, dir_curclust
, get_dentfromdir_block
,
1069 mydata
->clust_size
* mydata
->sect_size
);
1071 printf("Error: writing directory entry\n");
1074 free(mydata
->fatbuf
);
1078 int file_fat_write(const char *filename
, void *buffer
, loff_t offset
,
1079 loff_t maxsize
, loff_t
*actwrite
)
1082 printf("Error: non zero offset is currently not supported.\n");
1086 printf("writing %s\n", filename
);
1087 return do_fat_write(filename
, buffer
, maxsize
, actwrite
);