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 startblock += mydata->fat_sect;
122 if (getsize > fatlength)
126 if (disk_write(startblock, getsize, bufptr) < 0) {
127 debug("error: writing FAT blocks\n");
131 if (num_of_fats == 2) {
132 /* Update corresponding second FAT blocks */
133 startblock += mydata->fatlength;
134 if (disk_write(startblock, getsize, bufptr) < 0) {
135 debug("error: writing second FAT blocks\n");
139 mydata->fat_dirty = 0;
145 * Get the entry at index 'entry' in a FAT (12/16/32) table.
146 * On failure 0x00 is returned.
147 * When bufnum is changed, write back the previous fatbuf to the disk.
149 static __u32 get_fatent_value(fsdata *mydata, __u32 entry)
156 if (CHECK_CLUST(entry, mydata->fatsize)) {
157 printf("Error: Invalid FAT entry: 0x%08x\n", entry);
161 switch (mydata->fatsize) {
163 bufnum = entry / FAT32BUFSIZE;
164 offset = entry - bufnum * FAT32BUFSIZE;
167 bufnum = entry / FAT16BUFSIZE;
168 offset = entry - bufnum * FAT16BUFSIZE;
171 bufnum = entry / FAT12BUFSIZE;
172 offset = entry - bufnum * FAT12BUFSIZE;
176 /* Unsupported FAT size */
180 debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
181 mydata->fatsize, entry, entry, offset, offset);
183 /* Read a new block of FAT entries into the cache. */
184 if (bufnum != mydata->fatbufnum) {
185 int getsize = FATBUFBLOCKS;
186 __u8 *bufptr = mydata->fatbuf;
187 __u32 fatlength = mydata->fatlength;
188 __u32 startblock = bufnum * FATBUFBLOCKS;
190 if (getsize > fatlength)
193 startblock += mydata->fat_sect; /* Offset from start of disk */
195 /* Write back the fatbuf to the disk */
196 if (flush_dirty_fat_buffer(mydata) < 0)
199 if (disk_read(startblock, getsize, bufptr) < 0) {
200 debug("Error reading FAT blocks\n");
203 mydata->fatbufnum = bufnum;
206 /* Get the actual entry from the table */
207 switch (mydata->fatsize) {
209 ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
212 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
215 off16 = (offset * 3) / 4;
217 switch (offset & 0x3) {
219 ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
223 val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
225 val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
227 ret = (val2 << 4) | (val1 >> 12);
230 val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
232 val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
234 ret = (val2 << 8) | (val1 >> 8);
237 ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
238 ret = (ret & 0xfff0) >> 4;
245 debug("FAT%d: ret: %08x, entry: %08x, offset: %04x\n",
246 mydata->fatsize, ret, entry, offset);
252 * Set the file name information from 'name' into 'slotptr',
254 static int str2slot(dir_slot *slotptr, const char *name, int *idx)
258 for (j = 0; j <= 8; j += 2) {
259 if (name[*idx] == 0x00) {
260 slotptr->name0_4[j] = 0;
261 slotptr->name0_4[j + 1] = 0;
265 slotptr->name0_4[j] = name[*idx];
269 for (j = 0; j <= 10; j += 2) {
270 if (name[*idx] == 0x00) {
271 slotptr->name5_10[j] = 0;
272 slotptr->name5_10[j + 1] = 0;
276 slotptr->name5_10[j] = name[*idx];
280 for (j = 0; j <= 2; j += 2) {
281 if (name[*idx] == 0x00) {
282 slotptr->name11_12[j] = 0;
283 slotptr->name11_12[j + 1] = 0;
287 slotptr->name11_12[j] = name[*idx];
292 if (name[*idx] == 0x00)
296 /* Not used characters are filled with 0xff 0xff */
298 for (; end_idx < 5; end_idx++) {
299 slotptr->name0_4[end_idx * 2] = 0xff;
300 slotptr->name0_4[end_idx * 2 + 1] = 0xff;
305 for (; end_idx < 6; end_idx++) {
306 slotptr->name5_10[end_idx * 2] = 0xff;
307 slotptr->name5_10[end_idx * 2 + 1] = 0xff;
312 for (; end_idx < 2; end_idx++) {
313 slotptr->name11_12[end_idx * 2] = 0xff;
314 slotptr->name11_12[end_idx * 2 + 1] = 0xff;
320 static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
321 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
324 * Fill dir_slot entries with appropriate name, id, and attr
325 * The real directory entry is returned by 'dentptr'
328 fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
330 __u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
331 dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
332 __u8 counter = 0, checksum;
335 /* Get short file name checksum value */
336 checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
339 memset(slotptr, 0x00, sizeof(dir_slot));
340 ret = str2slot(slotptr, l_name, &idx);
341 slotptr->id = ++counter;
342 slotptr->attr = ATTR_VFAT;
343 slotptr->alias_checksum = checksum;
348 slotptr->id |= LAST_LONG_ENTRY_MASK;
350 while (counter >= 1) {
351 if (is_next_clust(mydata, *dentptr)) {
352 /* A new cluster is allocated for directory table */
353 flush_dir_table(mydata, dentptr);
355 memcpy(*dentptr, slotptr, sizeof(dir_slot));
361 if (is_next_clust(mydata, *dentptr)) {
362 /* A new cluster is allocated for directory table */
363 flush_dir_table(mydata, dentptr);
367 static __u32 dir_curclust;
370 * Extract the full long filename starting at 'retdent' (which is really
371 * a slot) into 'l_name'. If successful also copy the real directory entry
373 * If additional adjacent cluster for directory entries is read into memory,
374 * then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
375 * the location of the real directory entry is returned by 'retdent'
376 * Return 0 on success, -1 otherwise.
379 get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
380 dir_entry **retdent, char *l_name)
383 dir_slot *slotptr = (dir_slot *)(*retdent);
384 dir_slot *slotptr2 = NULL;
385 __u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
388 __u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
389 int idx = 0, cur_position = 0;
391 if (counter > VFAT_MAXSEQ) {
392 debug("Error: VFAT name is too long\n");
396 while ((__u8 *)slotptr < buflimit) {
399 if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
405 if ((__u8 *)slotptr >= buflimit) {
408 curclust = get_fatent_value(mydata, dir_curclust);
409 if (CHECK_CLUST(curclust, mydata->fatsize)) {
410 debug("curclust: 0x%x\n", curclust);
411 printf("Invalid FAT entry\n");
415 dir_curclust = curclust;
417 if (get_cluster(mydata, curclust, get_contents_vfatname_block,
418 mydata->clust_size * mydata->sect_size) != 0) {
419 debug("Error: reading directory block\n");
423 slotptr2 = (dir_slot *)get_contents_vfatname_block;
424 while (counter > 0) {
425 if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
432 /* Save the real directory entry */
433 realdent = (dir_entry *)slotptr2;
434 while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
436 slot2str(slotptr2, l_name, &idx);
439 /* Save the real directory entry */
440 realdent = (dir_entry *)slotptr;
445 if (slot2str(slotptr, l_name, &idx))
447 } while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
450 if (*l_name == DELETED_FLAG)
452 else if (*l_name == aRING)
453 *l_name = DELETED_FLAG;
456 /* Return the real directory entry */
460 memcpy(get_dentfromdir_block, get_contents_vfatname_block,
461 mydata->clust_size * mydata->sect_size);
462 cur_position = (__u8 *)realdent - get_contents_vfatname_block;
463 *retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
470 * Set the entry at index 'entry' in a FAT (16/32) table.
472 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
474 __u32 bufnum, offset;
476 switch (mydata->fatsize) {
478 bufnum = entry / FAT32BUFSIZE;
479 offset = entry - bufnum * FAT32BUFSIZE;
482 bufnum = entry / FAT16BUFSIZE;
483 offset = entry - bufnum * FAT16BUFSIZE;
486 /* Unsupported FAT size */
490 /* Read a new block of FAT entries into the cache. */
491 if (bufnum != mydata->fatbufnum) {
492 int getsize = FATBUFBLOCKS;
493 __u8 *bufptr = mydata->fatbuf;
494 __u32 fatlength = mydata->fatlength;
495 __u32 startblock = bufnum * FATBUFBLOCKS;
497 fatlength *= mydata->sect_size;
498 startblock += mydata->fat_sect;
500 if (getsize > fatlength)
503 if (flush_dirty_fat_buffer(mydata) < 0)
506 if (disk_read(startblock, getsize, bufptr) < 0) {
507 debug("Error reading FAT blocks\n");
510 mydata->fatbufnum = bufnum;
514 mydata->fat_dirty = 1;
516 /* Set the actual entry */
517 switch (mydata->fatsize) {
519 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
522 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
532 * Determine the next free cluster after 'entry' in a FAT (16/32) table
533 * and link it to 'entry'. EOC marker is not set on returned entry.
535 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
537 __u32 next_fat, next_entry = entry + 1;
540 next_fat = get_fatent_value(mydata, next_entry);
542 /* found free entry, link to entry */
543 set_fatent_value(mydata, entry, next_entry);
548 debug("FAT%d: entry: %08x, entry_value: %04x\n",
549 mydata->fatsize, entry, next_entry);
555 * Write at most 'size' bytes from 'buffer' into the specified cluster.
556 * Return 0 on success, -1 otherwise.
559 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
567 startsect = mydata->data_begin +
568 clustnum * mydata->clust_size;
570 startsect = mydata->rootdir_sect;
572 debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
574 if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
575 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
577 printf("FAT: Misaligned buffer address (%p)\n", buffer);
579 while (size >= mydata->sect_size) {
580 memcpy(tmpbuf, buffer, mydata->sect_size);
581 ret = disk_write(startsect++, 1, tmpbuf);
583 debug("Error writing data (got %d)\n", ret);
587 buffer += mydata->sect_size;
588 size -= mydata->sect_size;
590 } else if (size >= mydata->sect_size) {
591 idx = size / mydata->sect_size;
592 ret = disk_write(startsect, idx, buffer);
594 debug("Error writing data (got %d)\n", ret);
599 idx *= mydata->sect_size;
605 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
607 memcpy(tmpbuf, buffer, size);
608 ret = disk_write(startsect, 1, tmpbuf);
610 debug("Error writing data (got %d)\n", ret);
619 * Find the first empty cluster
621 static int find_empty_cluster(fsdata *mydata)
623 __u32 fat_val, entry = 3;
626 fat_val = get_fatent_value(mydata, entry);
636 * Write directory entries in 'get_dentfromdir_block' to block device
638 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
640 int dir_newclust = 0;
642 if (set_cluster(mydata, dir_curclust,
643 get_dentfromdir_block,
644 mydata->clust_size * mydata->sect_size) != 0) {
645 printf("error: wrinting directory entry\n");
648 dir_newclust = find_empty_cluster(mydata);
649 set_fatent_value(mydata, dir_curclust, dir_newclust);
650 if (mydata->fatsize == 32)
651 set_fatent_value(mydata, dir_newclust, 0xffffff8);
652 else if (mydata->fatsize == 16)
653 set_fatent_value(mydata, dir_newclust, 0xfff8);
655 dir_curclust = dir_newclust;
657 if (flush_dirty_fat_buffer(mydata) < 0)
660 memset(get_dentfromdir_block, 0x00,
661 mydata->clust_size * mydata->sect_size);
663 *dentptr = (dir_entry *) get_dentfromdir_block;
667 * Set empty cluster from 'entry' to the end of a file
669 static int clear_fatent(fsdata *mydata, __u32 entry)
674 fat_val = get_fatent_value(mydata, entry);
676 set_fatent_value(mydata, entry, 0);
680 if (fat_val == 0xfffffff || fat_val == 0xffff)
686 /* Flush fat buffer */
687 if (flush_dirty_fat_buffer(mydata) < 0)
694 * Write at most 'maxsize' bytes from 'buffer' into
695 * the file associated with 'dentptr'
696 * Update the number of bytes written in *gotsize and return 0
697 * or return -1 on fatal errors.
700 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
701 loff_t maxsize, loff_t *gotsize)
703 loff_t filesize = FAT2CPU32(dentptr->size);
704 unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
705 __u32 curclust = START(dentptr);
706 __u32 endclust = 0, newclust = 0;
710 debug("Filesize: %llu bytes\n", filesize);
712 if (maxsize > 0 && filesize > maxsize)
715 debug("%llu bytes\n", filesize);
719 debug("error: nonempty clusterless file!\n");
725 actsize = bytesperclust;
728 /* search for consecutive clusters */
729 while (actsize < filesize) {
730 newclust = determine_fatent(mydata, endclust);
732 if ((newclust - 1) != endclust)
735 if (CHECK_CLUST(newclust, mydata->fatsize)) {
736 debug("newclust: 0x%x\n", newclust);
737 debug("Invalid FAT entry\n");
741 actsize += bytesperclust;
744 /* set remaining bytes */
746 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
747 debug("error: writing cluster\n");
752 /* Mark end of file in FAT */
753 if (mydata->fatsize == 16)
755 else if (mydata->fatsize == 32)
756 newclust = 0xfffffff;
757 set_fatent_value(mydata, endclust, newclust);
761 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
762 debug("error: writing cluster\n");
769 if (CHECK_CLUST(newclust, mydata->fatsize)) {
770 debug("newclust: 0x%x\n", newclust);
771 debug("Invalid FAT entry\n");
774 actsize = bytesperclust;
775 curclust = endclust = newclust;
780 * Set start cluster in directory entry
782 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
785 if (mydata->fatsize == 32)
787 cpu_to_le16((start_cluster & 0xffff0000) >> 16);
788 dentptr->start = cpu_to_le16(start_cluster & 0xffff);
794 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
795 const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
797 set_start_cluster(mydata, dentptr, start_cluster);
798 dentptr->size = cpu_to_le32(size);
800 dentptr->attr = attr;
802 set_name(dentptr, filename);
806 * Check whether adding a file makes the file system to
807 * exceed the size of the block device
808 * Return -1 when overflow occurs, otherwise return 0
810 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
812 __u32 startsect, sect_num, offset;
815 startsect = mydata->data_begin +
816 clustnum * mydata->clust_size;
818 startsect = mydata->rootdir_sect;
821 sect_num = div_u64_rem(size, mydata->sect_size, &offset);
826 if (startsect + sect_num > cur_part_info.start + total_sector)
832 * Check if adding several entries exceed one cluster boundary
834 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
838 cur_position = (__u8 *)dentptr - get_dentfromdir_block;
840 if (cur_position >= mydata->clust_size * mydata->sect_size)
846 static dir_entry *empty_dentptr;
848 * Find a directory entry based on filename or start cluster number
849 * If the directory entry is not found,
850 * the new position for writing a directory entry will be returned
852 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
853 char *filename, dir_entry *retdent, __u32 start)
855 __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
857 debug("get_dentfromdir: %s\n", filename);
864 if (get_cluster(mydata, curclust, get_dentfromdir_block,
865 mydata->clust_size * mydata->sect_size) != 0) {
866 printf("Error: reading directory block\n");
870 dentptr = (dir_entry *)get_dentfromdir_block;
872 dir_curclust = curclust;
874 for (i = 0; i < DIRENTSPERCLUST; i++) {
875 char s_name[14], l_name[VFAT_MAXLEN_BYTES];
878 if (dentptr->name[0] == DELETED_FLAG) {
880 if (is_next_clust(mydata, dentptr))
884 if ((dentptr->attr & ATTR_VOLUME)) {
886 (dentptr->attr & ATTR_VFAT) &&
887 (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
888 get_long_file_name(mydata, curclust,
889 get_dentfromdir_block,
891 debug("vfatname: |%s|\n", l_name);
893 /* Volume label or VFAT entry */
895 if (is_next_clust(mydata, dentptr))
900 if (dentptr->name[0] == 0) {
901 debug("Dentname == NULL - %d\n", i);
902 empty_dentptr = dentptr;
906 get_name(dentptr, s_name);
908 if (strcmp(filename, s_name)
909 && strcmp(filename, l_name)) {
910 debug("Mismatch: |%s|%s|\n",
913 if (is_next_clust(mydata, dentptr))
918 memcpy(retdent, dentptr, sizeof(dir_entry));
920 debug("DentName: %s", s_name);
921 debug(", start: 0x%x", START(dentptr));
922 debug(", size: 0x%x %s\n",
923 FAT2CPU32(dentptr->size),
924 (dentptr->attr & ATTR_DIR) ?
931 * In FAT16/12, the root dir is locate before data area, shows
933 * -------------------------------------------------------------
934 * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
935 * -------------------------------------------------------------
937 * As a result if curclust is in Root dir, it is a negative
941 if (mydata->fatsize != 32 && (int)curclust <= 1) {
942 /* Current clust is in root dir, set to next clust */
944 if ((int)curclust <= 1)
945 continue; /* continue to find */
947 /* Reach the end of root dir */
948 empty_dentptr = dentptr;
952 curclust = get_fatent_value(mydata, dir_curclust);
953 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
954 empty_dentptr = dentptr;
957 if (CHECK_CLUST(curclust, mydata->fatsize)) {
958 debug("curclust: 0x%x\n", curclust);
959 debug("Invalid FAT entry\n");
967 static int do_fat_write(const char *filename, void *buffer, loff_t size,
970 dir_entry *dentptr, *retdent;
976 fsdata *mydata = &datablock;
978 int ret = -1, name_len;
979 char l_filename[VFAT_MAXLEN_BYTES];
984 if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
985 debug("error: reading boot sector\n");
989 total_sector = bs.total_sect;
990 if (total_sector == 0)
991 total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
993 if (mydata->fatsize == 32)
994 mydata->fatlength = bs.fat32_length;
996 mydata->fatlength = bs.fat_length;
998 mydata->fat_sect = bs.reserved;
1000 cursect = mydata->rootdir_sect
1001 = mydata->fat_sect + mydata->fatlength * bs.fats;
1002 num_of_fats = bs.fats;
1004 mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
1005 mydata->clust_size = bs.cluster_size;
1007 if (mydata->fatsize == 32) {
1008 mydata->data_begin = mydata->rootdir_sect -
1009 (mydata->clust_size * 2);
1013 rootdir_size = ((bs.dir_entries[1] * (int)256 +
1014 bs.dir_entries[0]) *
1015 sizeof(dir_entry)) /
1017 mydata->data_begin = mydata->rootdir_sect +
1019 (mydata->clust_size * 2);
1022 mydata->fatbufnum = -1;
1023 mydata->fat_dirty = 0;
1024 mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
1025 if (mydata->fatbuf == NULL) {
1026 debug("Error: allocating memory\n");
1030 if (disk_read(cursect,
1031 (mydata->fatsize == 32) ?
1032 (mydata->clust_size) :
1033 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
1034 debug("Error: reading rootdir block\n");
1037 dentptr = (dir_entry *) do_fat_read_at_block;
1039 name_len = strlen(filename);
1040 if (name_len >= VFAT_MAXLEN_BYTES)
1041 name_len = VFAT_MAXLEN_BYTES - 1;
1043 memcpy(l_filename, filename, name_len);
1044 l_filename[name_len] = 0; /* terminate the string */
1045 downcase(l_filename);
1047 startsect = mydata->rootdir_sect;
1048 retdent = find_directory_entry(mydata, startsect,
1049 l_filename, dentptr, 0);
1051 /* Update file size and start_cluster in a directory entry */
1052 retdent->size = cpu_to_le32(size);
1053 start_cluster = START(retdent);
1055 if (start_cluster) {
1057 ret = check_overflow(mydata, start_cluster,
1060 printf("Error: %llu overflow\n", size);
1065 ret = clear_fatent(mydata, start_cluster);
1067 printf("Error: clearing FAT entries\n");
1072 set_start_cluster(mydata, retdent, 0);
1074 ret = start_cluster = find_empty_cluster(mydata);
1076 printf("Error: finding empty cluster\n");
1080 ret = check_overflow(mydata, start_cluster, size);
1082 printf("Error: %llu overflow\n", size);
1086 set_start_cluster(mydata, retdent, start_cluster);
1089 /* Set short name to set alias checksum field in dir_slot */
1090 set_name(empty_dentptr, filename);
1091 fill_dir_slot(mydata, &empty_dentptr, filename);
1094 ret = start_cluster = find_empty_cluster(mydata);
1096 printf("Error: finding empty cluster\n");
1100 ret = check_overflow(mydata, start_cluster, size);
1102 printf("Error: %llu overflow\n", size);
1109 /* Set attribute as archieve for regular file */
1110 fill_dentry(mydata, empty_dentptr, filename,
1111 start_cluster, size, 0x20);
1113 retdent = empty_dentptr;
1116 ret = set_contents(mydata, retdent, buffer, size, actwrite);
1118 printf("Error: writing contents\n");
1121 debug("attempt to write 0x%llx bytes\n", *actwrite);
1123 /* Flush fat buffer */
1124 ret = flush_dirty_fat_buffer(mydata);
1126 printf("Error: flush fat buffer\n");
1130 /* Write directory table to device */
1131 ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
1132 mydata->clust_size * mydata->sect_size);
1134 printf("Error: writing directory entry\n");
1137 free(mydata->fatbuf);
1141 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1142 loff_t maxsize, loff_t *actwrite)
1145 printf("Error: non zero offset is currently not supported.\n");
1149 printf("writing %s\n", filename);
1150 return do_fat_write(filename, buffer, maxsize, actwrite);