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 (12/16/32) table.
472 static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
474 __u32 bufnum, offset, off16;
477 switch (mydata->fatsize) {
479 bufnum = entry / FAT32BUFSIZE;
480 offset = entry - bufnum * FAT32BUFSIZE;
483 bufnum = entry / FAT16BUFSIZE;
484 offset = entry - bufnum * FAT16BUFSIZE;
487 bufnum = entry / FAT12BUFSIZE;
488 offset = entry - bufnum * FAT12BUFSIZE;
491 /* Unsupported FAT size */
495 /* Read a new block of FAT entries into the cache. */
496 if (bufnum != mydata->fatbufnum) {
497 int getsize = FATBUFBLOCKS;
498 __u8 *bufptr = mydata->fatbuf;
499 __u32 fatlength = mydata->fatlength;
500 __u32 startblock = bufnum * FATBUFBLOCKS;
502 fatlength *= mydata->sect_size;
503 startblock += mydata->fat_sect;
505 if (getsize > fatlength)
508 if (flush_dirty_fat_buffer(mydata) < 0)
511 if (disk_read(startblock, getsize, bufptr) < 0) {
512 debug("Error reading FAT blocks\n");
515 mydata->fatbufnum = bufnum;
519 mydata->fat_dirty = 1;
521 /* Set the actual entry */
522 switch (mydata->fatsize) {
524 ((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
527 ((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
530 off16 = (offset * 3) / 4;
532 switch (offset & 0x3) {
534 val1 = cpu_to_le16(entry_value) & 0xfff;
535 ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
536 ((__u16 *)mydata->fatbuf)[off16] |= val1;
539 val1 = cpu_to_le16(entry_value) & 0xf;
540 val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
542 ((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
543 ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
545 ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
546 ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
549 val1 = cpu_to_le16(entry_value) & 0xff;
550 val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
552 ((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
553 ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
555 ((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
556 ((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
559 val1 = cpu_to_le16(entry_value) & 0xfff;
560 ((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
561 ((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
576 * Determine the next free cluster after 'entry' in a FAT (12/16/32) table
577 * and link it to 'entry'. EOC marker is not set on returned entry.
579 static __u32 determine_fatent(fsdata *mydata, __u32 entry)
581 __u32 next_fat, next_entry = entry + 1;
584 next_fat = get_fatent_value(mydata, next_entry);
586 /* found free entry, link to entry */
587 set_fatent_value(mydata, entry, next_entry);
592 debug("FAT%d: entry: %08x, entry_value: %04x\n",
593 mydata->fatsize, entry, next_entry);
599 * Write at most 'size' bytes from 'buffer' into the specified cluster.
600 * Return 0 on success, -1 otherwise.
603 set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
611 startsect = mydata->data_begin +
612 clustnum * mydata->clust_size;
614 startsect = mydata->rootdir_sect;
616 debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
618 if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
619 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
621 printf("FAT: Misaligned buffer address (%p)\n", buffer);
623 while (size >= mydata->sect_size) {
624 memcpy(tmpbuf, buffer, mydata->sect_size);
625 ret = disk_write(startsect++, 1, tmpbuf);
627 debug("Error writing data (got %d)\n", ret);
631 buffer += mydata->sect_size;
632 size -= mydata->sect_size;
634 } else if (size >= mydata->sect_size) {
635 idx = size / mydata->sect_size;
636 ret = disk_write(startsect, idx, buffer);
638 debug("Error writing data (got %d)\n", ret);
643 idx *= mydata->sect_size;
649 ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
651 memcpy(tmpbuf, buffer, size);
652 ret = disk_write(startsect, 1, tmpbuf);
654 debug("Error writing data (got %d)\n", ret);
663 * Find the first empty cluster
665 static int find_empty_cluster(fsdata *mydata)
667 __u32 fat_val, entry = 3;
670 fat_val = get_fatent_value(mydata, entry);
680 * Write directory entries in 'get_dentfromdir_block' to block device
682 static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
684 int dir_newclust = 0;
686 if (set_cluster(mydata, dir_curclust,
687 get_dentfromdir_block,
688 mydata->clust_size * mydata->sect_size) != 0) {
689 printf("error: wrinting directory entry\n");
692 dir_newclust = find_empty_cluster(mydata);
693 set_fatent_value(mydata, dir_curclust, dir_newclust);
694 if (mydata->fatsize == 32)
695 set_fatent_value(mydata, dir_newclust, 0xffffff8);
696 else if (mydata->fatsize == 16)
697 set_fatent_value(mydata, dir_newclust, 0xfff8);
698 else if (mydata->fatsize == 12)
699 set_fatent_value(mydata, dir_newclust, 0xff8);
701 dir_curclust = dir_newclust;
703 if (flush_dirty_fat_buffer(mydata) < 0)
706 memset(get_dentfromdir_block, 0x00,
707 mydata->clust_size * mydata->sect_size);
709 *dentptr = (dir_entry *) get_dentfromdir_block;
713 * Set empty cluster from 'entry' to the end of a file
715 static int clear_fatent(fsdata *mydata, __u32 entry)
719 while (!CHECK_CLUST(entry, mydata->fatsize)) {
720 fat_val = get_fatent_value(mydata, entry);
722 set_fatent_value(mydata, entry, 0);
729 /* Flush fat buffer */
730 if (flush_dirty_fat_buffer(mydata) < 0)
737 * Write at most 'maxsize' bytes from 'buffer' into
738 * the file associated with 'dentptr'
739 * Update the number of bytes written in *gotsize and return 0
740 * or return -1 on fatal errors.
743 set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
744 loff_t maxsize, loff_t *gotsize)
746 loff_t filesize = FAT2CPU32(dentptr->size);
747 unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
748 __u32 curclust = START(dentptr);
749 __u32 endclust = 0, newclust = 0;
753 debug("Filesize: %llu bytes\n", filesize);
755 if (maxsize > 0 && filesize > maxsize)
758 debug("%llu bytes\n", filesize);
762 debug("error: nonempty clusterless file!\n");
768 actsize = bytesperclust;
771 /* search for consecutive clusters */
772 while (actsize < filesize) {
773 newclust = determine_fatent(mydata, endclust);
775 if ((newclust - 1) != endclust)
778 if (CHECK_CLUST(newclust, mydata->fatsize)) {
779 debug("newclust: 0x%x\n", newclust);
780 debug("Invalid FAT entry\n");
784 actsize += bytesperclust;
787 /* set remaining bytes */
789 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
790 debug("error: writing cluster\n");
795 /* Mark end of file in FAT */
796 if (mydata->fatsize == 12)
798 else if (mydata->fatsize == 16)
800 else if (mydata->fatsize == 32)
801 newclust = 0xfffffff;
802 set_fatent_value(mydata, endclust, newclust);
806 if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
807 debug("error: writing cluster\n");
814 if (CHECK_CLUST(newclust, mydata->fatsize)) {
815 debug("newclust: 0x%x\n", newclust);
816 debug("Invalid FAT entry\n");
819 actsize = bytesperclust;
820 curclust = endclust = newclust;
825 * Set start cluster in directory entry
827 static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
830 if (mydata->fatsize == 32)
832 cpu_to_le16((start_cluster & 0xffff0000) >> 16);
833 dentptr->start = cpu_to_le16(start_cluster & 0xffff);
839 static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
840 const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
842 set_start_cluster(mydata, dentptr, start_cluster);
843 dentptr->size = cpu_to_le32(size);
845 dentptr->attr = attr;
847 set_name(dentptr, filename);
851 * Check whether adding a file makes the file system to
852 * exceed the size of the block device
853 * Return -1 when overflow occurs, otherwise return 0
855 static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
857 __u32 startsect, sect_num, offset;
860 startsect = mydata->data_begin +
861 clustnum * mydata->clust_size;
863 startsect = mydata->rootdir_sect;
866 sect_num = div_u64_rem(size, mydata->sect_size, &offset);
871 if (startsect + sect_num > cur_part_info.start + total_sector)
877 * Check if adding several entries exceed one cluster boundary
879 static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
883 cur_position = (__u8 *)dentptr - get_dentfromdir_block;
885 if (cur_position >= mydata->clust_size * mydata->sect_size)
891 static dir_entry *empty_dentptr;
893 * Find a directory entry based on filename or start cluster number
894 * If the directory entry is not found,
895 * the new position for writing a directory entry will be returned
897 static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
898 char *filename, dir_entry *retdent, __u32 start)
900 __u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
902 debug("get_dentfromdir: %s\n", filename);
909 if (get_cluster(mydata, curclust, get_dentfromdir_block,
910 mydata->clust_size * mydata->sect_size) != 0) {
911 printf("Error: reading directory block\n");
915 dentptr = (dir_entry *)get_dentfromdir_block;
917 dir_curclust = curclust;
919 for (i = 0; i < DIRENTSPERCLUST; i++) {
920 char s_name[14], l_name[VFAT_MAXLEN_BYTES];
923 if (dentptr->name[0] == DELETED_FLAG) {
925 if (is_next_clust(mydata, dentptr))
929 if ((dentptr->attr & ATTR_VOLUME)) {
931 (dentptr->attr & ATTR_VFAT) &&
932 (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
933 get_long_file_name(mydata, curclust,
934 get_dentfromdir_block,
936 debug("vfatname: |%s|\n", l_name);
938 /* Volume label or VFAT entry */
940 if (is_next_clust(mydata, dentptr))
945 if (dentptr->name[0] == 0) {
946 debug("Dentname == NULL - %d\n", i);
947 empty_dentptr = dentptr;
951 get_name(dentptr, s_name);
953 if (strcmp(filename, s_name)
954 && strcmp(filename, l_name)) {
955 debug("Mismatch: |%s|%s|\n",
958 if (is_next_clust(mydata, dentptr))
963 memcpy(retdent, dentptr, sizeof(dir_entry));
965 debug("DentName: %s", s_name);
966 debug(", start: 0x%x", START(dentptr));
967 debug(", size: 0x%x %s\n",
968 FAT2CPU32(dentptr->size),
969 (dentptr->attr & ATTR_DIR) ?
976 * In FAT16/12, the root dir is locate before data area, shows
978 * -------------------------------------------------------------
979 * | Boot | FAT1 & 2 | Root dir | Data (start from cluster #2) |
980 * -------------------------------------------------------------
982 * As a result if curclust is in Root dir, it is a negative
986 if (mydata->fatsize != 32 && (int)curclust <= 1) {
987 /* Current clust is in root dir, set to next clust */
989 if ((int)curclust <= 1)
990 continue; /* continue to find */
992 /* Reach the end of root dir */
993 empty_dentptr = dentptr;
997 curclust = get_fatent_value(mydata, dir_curclust);
998 if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
999 empty_dentptr = dentptr;
1002 if (CHECK_CLUST(curclust, mydata->fatsize)) {
1003 debug("curclust: 0x%x\n", curclust);
1004 debug("Invalid FAT entry\n");
1012 static int do_fat_write(const char *filename, void *buffer, loff_t size,
1015 dir_entry *dentptr, *retdent;
1017 __u32 start_cluster;
1019 volume_info volinfo;
1021 fsdata *mydata = &datablock;
1023 int ret = -1, name_len;
1024 char l_filename[VFAT_MAXLEN_BYTES];
1029 if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
1030 debug("error: reading boot sector\n");
1034 total_sector = bs.total_sect;
1035 if (total_sector == 0)
1036 total_sector = (int)cur_part_info.size; /* cast of lbaint_t */
1038 if (mydata->fatsize == 32)
1039 mydata->fatlength = bs.fat32_length;
1041 mydata->fatlength = bs.fat_length;
1043 mydata->fat_sect = bs.reserved;
1045 cursect = mydata->rootdir_sect
1046 = mydata->fat_sect + mydata->fatlength * bs.fats;
1047 num_of_fats = bs.fats;
1049 mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
1050 mydata->clust_size = bs.cluster_size;
1052 if (mydata->fatsize == 32) {
1053 mydata->data_begin = mydata->rootdir_sect -
1054 (mydata->clust_size * 2);
1058 rootdir_size = ((bs.dir_entries[1] * (int)256 +
1059 bs.dir_entries[0]) *
1060 sizeof(dir_entry)) /
1062 mydata->data_begin = mydata->rootdir_sect +
1064 (mydata->clust_size * 2);
1067 mydata->fatbufnum = -1;
1068 mydata->fat_dirty = 0;
1069 mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
1070 if (mydata->fatbuf == NULL) {
1071 debug("Error: allocating memory\n");
1075 if (disk_read(cursect,
1076 (mydata->fatsize == 32) ?
1077 (mydata->clust_size) :
1078 PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
1079 debug("Error: reading rootdir block\n");
1082 dentptr = (dir_entry *) do_fat_read_at_block;
1084 name_len = strlen(filename);
1085 if (name_len >= VFAT_MAXLEN_BYTES)
1086 name_len = VFAT_MAXLEN_BYTES - 1;
1088 memcpy(l_filename, filename, name_len);
1089 l_filename[name_len] = 0; /* terminate the string */
1090 downcase(l_filename);
1092 startsect = mydata->rootdir_sect;
1093 retdent = find_directory_entry(mydata, startsect,
1094 l_filename, dentptr, 0);
1096 /* Update file size and start_cluster in a directory entry */
1097 retdent->size = cpu_to_le32(size);
1098 start_cluster = START(retdent);
1100 if (start_cluster) {
1102 ret = check_overflow(mydata, start_cluster,
1105 printf("Error: %llu overflow\n", size);
1110 ret = clear_fatent(mydata, start_cluster);
1112 printf("Error: clearing FAT entries\n");
1117 set_start_cluster(mydata, retdent, 0);
1119 ret = start_cluster = find_empty_cluster(mydata);
1121 printf("Error: finding empty cluster\n");
1125 ret = check_overflow(mydata, start_cluster, size);
1127 printf("Error: %llu overflow\n", size);
1131 set_start_cluster(mydata, retdent, start_cluster);
1134 /* Set short name to set alias checksum field in dir_slot */
1135 set_name(empty_dentptr, filename);
1136 fill_dir_slot(mydata, &empty_dentptr, filename);
1139 ret = start_cluster = find_empty_cluster(mydata);
1141 printf("Error: finding empty cluster\n");
1145 ret = check_overflow(mydata, start_cluster, size);
1147 printf("Error: %llu overflow\n", size);
1154 /* Set attribute as archieve for regular file */
1155 fill_dentry(mydata, empty_dentptr, filename,
1156 start_cluster, size, 0x20);
1158 retdent = empty_dentptr;
1161 ret = set_contents(mydata, retdent, buffer, size, actwrite);
1163 printf("Error: writing contents\n");
1166 debug("attempt to write 0x%llx bytes\n", *actwrite);
1168 /* Flush fat buffer */
1169 ret = flush_dirty_fat_buffer(mydata);
1171 printf("Error: flush fat buffer\n");
1175 /* Write directory table to device */
1176 ret = set_cluster(mydata, dir_curclust, get_dentfromdir_block,
1177 mydata->clust_size * mydata->sect_size);
1179 printf("Error: writing directory entry\n");
1182 free(mydata->fatbuf);
1186 int file_fat_write(const char *filename, void *buffer, loff_t offset,
1187 loff_t maxsize, loff_t *actwrite)
1190 printf("Error: non zero offset is currently not supported.\n");
1194 printf("writing %s\n", filename);
1195 return do_fat_write(filename, buffer, maxsize, actwrite);