2 * Copyright © 2013 Keith Packard <keithp@keithp.com>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25 /* Include FAT commands */
27 #define FAT_COMMANDS 1
30 /* Spew FAT tracing */
34 #define DBG(...) printf(__VA_ARGS__)
40 * Basic file system types
43 typedef ao_fat_offset_t offset_t;
44 typedef ao_fat_sector_t sector_t;
45 typedef ao_fat_cluster_t cluster_t;
46 typedef ao_fat_dirent_t dirent_t;
47 typedef ao_fat_cluster_offset_t cluster_offset_t;
49 /* Partition information, sector numbers */
51 static uint8_t partition_type;
52 static sector_t partition_start, partition_end;
54 #define AO_FAT_BAD_CLUSTER 0xffffff7
55 #define AO_FAT_LAST_CLUSTER 0xfffffff
56 #define AO_FAT_IS_LAST_CLUSTER(c) (((c) & 0xffffff8) == 0xffffff8)
57 #define AO_FAT_IS_LAST_CLUSTER16(c) (((c) & 0xfff8) == 0xfff8)
60 #define SECTOR_SIZE 512
61 #define SECTOR_MASK (SECTOR_SIZE - 1)
62 #define SECTOR_SHIFT 9
64 #define DIRENT_SIZE 32
66 /* File system parameters */
67 static uint8_t sectors_per_cluster;
68 static uint32_t bytes_per_cluster;
69 static sector_t reserved_sector_count;
70 static uint8_t number_fat;
71 static dirent_t root_entries;
72 static sector_t sectors_per_fat;
73 static cluster_t number_cluster;
74 static sector_t fat_start;
75 static sector_t root_start;
76 static sector_t data_start;
77 static cluster_t next_free;
78 static uint8_t filesystem_full;
80 /* FAT32 extra data */
82 static uint8_t fsinfo_dirty;
83 static cluster_t root_cluster;
84 static sector_t fsinfo_sector;
85 static cluster_t free_count;
88 * Deal with LSB FAT data structures
91 get_u32(uint8_t *base)
93 return ((uint32_t) base[0] |
94 ((uint32_t) base[1] << 8) |
95 ((uint32_t) base[2] << 16) |
96 ((uint32_t) base[3] << 24));
100 put_u32(uint8_t *base, uint32_t value)
103 base[1] = value >> 8;
104 base[2] = value >> 16;
105 base[3] = value >> 24;
109 get_u16(uint8_t *base)
111 return ((uint16_t) base[0] | ((uint16_t) base[1] << 8));
115 put_u16(uint8_t *base, uint16_t value)
118 base[1] = value >> 8;
122 ao_fat_cluster_valid(cluster_t cluster)
124 return (2 <= cluster && cluster < number_cluster);
127 /* Start using a sector */
129 ao_fat_sector_get(sector_t sector)
131 sector += partition_start;
132 if (sector >= partition_end)
134 return ao_bufio_get(sector);
137 /* Finish using a sector, 'w' is 1 if modified */
138 #define ao_fat_sector_put(b,w) ao_bufio_put(b,w)
140 /* Get the next cluster entry in the chain */
142 ao_fat_entry_read(cluster_t cluster)
149 if (!ao_fat_cluster_valid(cluster))
156 sector = cluster >> (SECTOR_SHIFT);
157 offset = cluster & SECTOR_MASK;
158 buf = ao_fat_sector_get(fat_start + sector);
163 ret = get_u32(buf + offset);
166 ret = get_u16(buf + offset);
167 if (AO_FAT_IS_LAST_CLUSTER16(ret))
170 ao_fat_sector_put(buf, 0);
174 /* Replace the referenced cluster entry in the chain with
175 * 'new_value'. Return the previous value.
178 ao_fat_entry_replace(cluster_t cluster, cluster_t new_value)
181 cluster_offset_t offset;
187 if (!ao_fat_cluster_valid(cluster))
190 /* Convert from cluster index to byte index */
195 sector = cluster >> SECTOR_SHIFT;
196 offset = cluster & SECTOR_MASK;
198 new_value &= 0xfffffff;
199 for (fat = 0; fat < number_fat; fat++) {
200 buf = ao_fat_sector_get(fat_start + fat * sectors_per_fat + sector);
204 old_value = get_u32(buf + offset);
205 put_u32(buf + offset, new_value | (old_value & 0xf0000000));
207 ret = old_value & 0xfffffff;
209 /* Track the free count if it wasn't marked
210 * invalid when we mounted the file system
212 if (free_count != 0xffffffff) {
213 if (new_value && !ret) {
216 } else if (!new_value && ret) {
224 ret = get_u16(buf + offset);
225 if (AO_FAT_IS_LAST_CLUSTER16(ret))
228 put_u16(buf + offset, new_value);
230 ao_fat_sector_put(buf, 1);
237 * Walk a cluster chain and mark
238 * all of them as free
241 ao_fat_free_cluster_chain(cluster_t cluster)
243 while (ao_fat_cluster_valid(cluster)) {
244 if (cluster < next_free) {
248 cluster = ao_fat_entry_replace(cluster, 0x00000000);
253 * ao_fat_cluster_seek
255 * The basic file system operation -- map a file cluster index to a
256 * partition cluster number. Done by computing the cluster number and
257 * then walking that many clusters from the first cluster. Returns
258 * 0xffff if we walk off the end of the file or the cluster chain
262 ao_fat_cluster_seek(cluster_t cluster, cluster_t distance)
265 cluster = ao_fat_entry_read(cluster);
266 if (!ao_fat_cluster_valid(cluster))
274 * ao_fat_cluster_set_size
276 * Set the number of clusters in the specified chain,
277 * freeing extra ones or alocating new ones as needed
279 * Returns AO_FAT_BAD_CLUSTER on allocation failure
283 ao_fat_cluster_set_size(cluster_t first_cluster, cluster_t size)
285 cluster_t clear_cluster = 0;
288 clear_cluster = first_cluster;
292 cluster_t last_cluster = 0;
293 cluster_t next_cluster;
295 /* Walk the cluster chain to the
296 * spot where it needs to change. That
297 * will either be the end of the chain (in case it needs to grow),
298 * or after the desired number of clusters, in which case it needs to shrink
300 next_cluster = first_cluster;
301 for (have = 0; have < size; have++) {
302 last_cluster = next_cluster;
303 next_cluster = ao_fat_entry_read(last_cluster);
304 if (!ao_fat_cluster_valid(next_cluster))
309 /* The file is large enough, truncate as needed */
310 if (ao_fat_cluster_valid(next_cluster)) {
311 /* Rewrite that cluster entry with 0xffff to mark the end of the chain */
312 clear_cluster = ao_fat_entry_replace(last_cluster, AO_FAT_LAST_CLUSTER);
315 /* The chain is already the right length, don't mess with it */
323 return AO_FAT_BAD_CLUSTER;
325 if (next_free < 2 || number_cluster <= next_free) {
330 /* See if there are enough free clusters in the file system */
333 #define loop_cluster for (free = next_free; need > 0;)
334 #define next_cluster \
335 if (++free == number_cluster) \
337 if (free == next_free) \
341 if (!ao_fat_entry_read(free))
345 /* Still need some, tell the user that we've failed */
348 return AO_FAT_BAD_CLUSTER;
351 /* Now go allocate those clusters and
352 * thread them onto the chain
356 if (!ao_fat_entry_read(free)) {
357 next_free = free + 1;
358 if (next_free >= number_cluster)
362 ao_fat_entry_replace(last_cluster, free);
364 first_cluster = free;
372 /* Mark the new end of the chain */
373 ao_fat_entry_replace(last_cluster, AO_FAT_LAST_CLUSTER);
377 /* Deallocate clusters off the end of the file */
378 if (ao_fat_cluster_valid(clear_cluster))
379 ao_fat_free_cluster_chain(clear_cluster);
380 return first_cluster;
383 /* Start using a root directory entry */
385 ao_fat_root_get(dirent_t e)
387 offset_t byte = e * DIRENT_SIZE;
388 sector_t sector = byte >> SECTOR_SHIFT;
389 cluster_offset_t offset = byte & SECTOR_MASK;
393 cluster_t cluster_distance = sector / sectors_per_cluster;
394 sector_t sector_index = sector % sectors_per_cluster;
395 cluster_t cluster = ao_fat_cluster_seek(root_cluster, cluster_distance);
397 if (ao_fat_cluster_valid(cluster))
398 sector = data_start + (cluster-2) * sectors_per_cluster + sector_index;
402 if (e >= root_entries)
404 sector = root_start + sector;
407 buf = ao_fat_sector_get(sector);
413 /* Finish using a root directory entry, 'w' is 1 if modified */
415 ao_fat_root_put(uint8_t *root, dirent_t e, uint8_t write)
417 cluster_offset_t offset = ((e * DIRENT_SIZE) & SECTOR_MASK);
418 uint8_t *buf = root - offset;
420 ao_fat_sector_put(buf, write);
426 * On FAT32, make the root directory at least 'ents' entries long
429 ao_fat_root_extend(dirent_t ents)
432 cluster_t cluster_size;
436 byte_size = ents * 0x20;
437 cluster_size = byte_size / bytes_per_cluster;
438 if (ao_fat_cluster_set_size(root_cluster, cluster_size) != AO_FAT_BAD_CLUSTER)
444 * ao_fat_setup_partition
446 * Load the boot block and find the first partition
449 ao_fat_setup_partition(void)
453 uint32_t partition_size;
455 mbr = ao_bufio_get(0);
457 return AO_FAT_FILESYSTEM_MBR_READ_FAILURE;
459 /* Check the signature */
460 if (mbr[0x1fe] != 0x55 || mbr[0x1ff] != 0xaa) {
461 DBG ("Invalid MBR signature %02x %02x\n",
462 mbr[0x1fe], mbr[0x1ff]);
463 ao_bufio_put(mbr, 0);
464 return AO_FAT_FILESYSTEM_INVALID_MBR_SIGNATURE;
467 /* Check to see if it's actually a boot block, in which
468 * case it's presumably not a paritioned device
471 if (mbr[0] == 0xeb) {
473 partition_size = get_u16(mbr + 0x13);
474 if (partition_size == 0)
475 partition_size = get_u32(mbr + 0x20);
477 /* Just use the first partition */
478 partition = &mbr[0x1be];
480 partition_type = partition[4];
481 switch (partition_type) {
482 case 4: /* FAT16 up to 32M */
483 case 6: /* FAT16 over 32M */
485 case 0x0b: /* FAT32 up to 2047GB */
486 case 0x0c: /* FAT32 LBA */
489 DBG ("Invalid partition type %02x\n", partition_type);
490 ao_bufio_put(mbr, 0);
491 return AO_FAT_FILESYSTEM_INVALID_PARTITION_TYPE;
494 partition_start = get_u32(partition+8);
495 partition_size = get_u32(partition+12);
496 if (partition_size == 0) {
497 DBG ("Zero-sized partition\n");
498 ao_bufio_put(mbr, 0);
499 return AO_FAT_FILESYSTEM_ZERO_SIZED_PARTITION;
502 partition_end = partition_start + partition_size;
503 ao_bufio_put(mbr, 0);
504 return AO_FAT_FILESYSTEM_SUCCESS;
508 ao_fat_setup_fs(void)
510 uint8_t *boot = ao_fat_sector_get(0);
511 uint32_t data_sectors;
514 return AO_FAT_FILESYSTEM_BOOT_READ_FAILURE;
516 /* Check the signature */
517 if (boot[0x1fe] != 0x55 || boot[0x1ff] != 0xaa) {
518 DBG ("Invalid BOOT signature %02x %02x\n",
519 boot[0x1fe], boot[0x1ff]);
520 ao_fat_sector_put(boot, 0);
521 return AO_FAT_FILESYSTEM_INVALID_BOOT_SIGNATURE;
524 /* Check the sector size */
525 if (get_u16(boot + 0xb) != SECTOR_SIZE) {
526 DBG ("Invalid sector size %d\n",
527 get_u16(boot + 0xb));
528 ao_fat_sector_put(boot, 0);
529 return AO_FAT_FILESYSTEM_INVALID_SECTOR_SIZE;
532 sectors_per_cluster = boot[0xd];
533 bytes_per_cluster = sectors_per_cluster << SECTOR_SHIFT;
534 reserved_sector_count = get_u16(boot+0xe);
535 number_fat = boot[0x10];
536 root_entries = get_u16(boot + 0x11);
537 sectors_per_fat = get_u16(boot+0x16);
539 if (sectors_per_fat == 0) {
541 sectors_per_fat = get_u32(boot+0x24);
542 root_cluster = get_u32(boot+0x2c);
543 fsinfo_sector = get_u16(boot + 0x30);
545 ao_fat_sector_put(boot, 0);
547 free_count = 0xffffffff;
549 if (fat32 && fsinfo_sector) {
550 uint8_t *fsinfo = ao_fat_sector_get(fsinfo_sector);
553 free_count = get_u32(fsinfo + 0x1e8);
554 next_free = get_u32(fsinfo + 0x1ec);
555 ao_fat_sector_put(fsinfo, 0);
559 fat_start = reserved_sector_count;;
560 root_start = fat_start + number_fat * sectors_per_fat;
561 data_start = root_start + ((root_entries * DIRENT_SIZE + SECTOR_MASK) >> SECTOR_SHIFT);
563 data_sectors = (partition_end - partition_start) - data_start;
565 number_cluster = data_sectors / sectors_per_cluster;
567 return AO_FAT_FILESYSTEM_SUCCESS;
571 * State for the current opened file
573 static struct ao_fat_dirent ao_file_dirent;
574 static uint32_t ao_file_offset;
575 static uint32_t ao_file_cluster_offset;
576 static cluster_t ao_file_cluster;
577 static uint8_t ao_file_opened;
578 static uint8_t ao_filesystem_setup;
579 static uint8_t ao_filesystem_status;
584 if (!ao_filesystem_setup) {
586 ao_filesystem_setup = 1;
589 /* Re-initialize all global state; this will help to allow the
590 * file system to get swapped someday
592 partition_type = partition_start = partition_end = 0;
593 sectors_per_cluster = bytes_per_cluster = reserved_sector_count = 0;
594 number_fat = root_entries = sectors_per_fat = 0;
595 number_cluster = fat_start = root_start = data_start = 0;
596 next_free = filesystem_full = 0;
597 fat32 = fsinfo_dirty = root_cluster = fsinfo_sector = free_count = 0;
598 memset(&ao_file_dirent, '\0', sizeof (ao_file_dirent));
600 ao_file_offset = ao_file_cluster_offset = ao_file_cluster = ao_file_opened = 0;
601 ao_filesystem_status = ao_fat_setup_partition();
602 if (ao_filesystem_status != AO_FAT_FILESYSTEM_SUCCESS)
603 return ao_filesystem_status;
604 ao_filesystem_status = ao_fat_setup_fs();
605 if (ao_filesystem_status != AO_FAT_FILESYSTEM_SUCCESS)
606 return ao_filesystem_status;
608 return ao_filesystem_status;
612 * Basic file operations
616 ao_fat_current_sector(void)
618 cluster_t cluster_offset;
619 uint32_t sector_offset;
620 uint16_t sector_index;
623 DBG("current sector offset %d size %d\n",
624 ao_file_offset, ao_file_dirent.size);
626 if (ao_file_offset > ao_file_dirent.size)
629 sector_offset = ao_file_offset >> SECTOR_SHIFT;
631 if (!ao_file_cluster || ao_file_offset < ao_file_cluster_offset) {
632 ao_file_cluster = ao_file_dirent.cluster;
633 ao_file_cluster_offset = 0;
634 DBG("\treset to start of file %08x\n", ao_file_cluster);
637 if (ao_file_cluster_offset + bytes_per_cluster <= ao_file_offset) {
638 cluster_t cluster_distance;
640 cluster_offset = sector_offset / sectors_per_cluster;
642 cluster_distance = cluster_offset - ao_file_cluster_offset / bytes_per_cluster;
644 DBG("\tseek forward %d clusters\n", cluster_distance);
645 cluster = ao_fat_cluster_seek(ao_file_cluster, cluster_distance);
647 if (!ao_fat_cluster_valid(cluster))
649 ao_file_cluster = cluster;
650 ao_file_cluster_offset = cluster_offset * bytes_per_cluster;
653 sector_index = sector_offset % sectors_per_cluster;
654 DBG("current cluster %08x sector_index %d sector %d\n",
655 ao_file_cluster, sector_index,
656 data_start + (uint32_t) (ao_file_cluster-2) * sectors_per_cluster + sector_index);
657 return data_start + (uint32_t) (ao_file_cluster-2) * sectors_per_cluster + sector_index;
661 ao_fat_set_offset(uint32_t offset)
663 DBG("Set offset %d\n", offset);
664 ao_file_offset = offset;
670 * Set the size of the current file, truncating or extending
671 * the cluster chain as needed
674 ao_fat_set_size(uint32_t size)
677 cluster_t first_cluster;
678 cluster_t have_clusters, need_clusters;
680 DBG ("Set size %d\n", size);
681 if (size == ao_file_dirent.size) {
682 DBG("\tsize match\n");
683 return AO_FAT_SUCCESS;
686 first_cluster = ao_file_dirent.cluster;
687 have_clusters = (ao_file_dirent.size + bytes_per_cluster - 1) / bytes_per_cluster;
688 need_clusters = (size + bytes_per_cluster - 1) / bytes_per_cluster;
690 DBG ("\tfirst cluster %08x have %d need %d\n", first_cluster, have_clusters, need_clusters);
691 if (have_clusters != need_clusters) {
692 if (ao_file_cluster && size >= ao_file_cluster_offset) {
693 cluster_t offset_clusters = (ao_file_cluster_offset + bytes_per_cluster) / bytes_per_cluster;
694 cluster_t extra_clusters = need_clusters - offset_clusters;
695 cluster_t next_cluster;
697 DBG ("\tset size relative offset_clusters %d extra_clusters %d\n",
698 offset_clusters, extra_clusters);
699 next_cluster = ao_fat_cluster_set_size(ao_file_cluster, extra_clusters);
700 if (next_cluster == AO_FAT_BAD_CLUSTER)
701 return -AO_FAT_ENOSPC;
703 DBG ("\tset size absolute need_clusters %d\n", need_clusters);
704 first_cluster = ao_fat_cluster_set_size(first_cluster, need_clusters);
706 if (first_cluster == AO_FAT_BAD_CLUSTER)
707 return -AO_FAT_ENOSPC;
711 DBG ("\tupdate directory size\n");
712 /* Update the directory entry */
713 dent = ao_fat_root_get(ao_file_dirent.entry);
716 put_u32(dent + 0x1c, size);
717 put_u16(dent + 0x1a, first_cluster);
719 put_u16(dent + 0x14, first_cluster >> 16);
720 ao_fat_root_put(dent, ao_file_dirent.entry, 1);
722 ao_file_dirent.size = size;
723 ao_file_dirent.cluster = first_cluster;
724 DBG ("set size done\n");
725 return AO_FAT_SUCCESS;
731 * Initialize a root directory entry
734 ao_fat_root_init(uint8_t *dent, char name[11], uint8_t attr)
736 memset(dent, '\0', 0x20);
737 memmove(dent, name, 11);
744 put_u16(dent + 0x0e, 0);
746 put_u16(dent + 0x10, 0);
748 put_u16(dent + 0x12, 0);
751 put_u16(dent + 0x16, 0);
753 put_u16(dent + 0x18, 0);
756 /* Low cluster bytes */
757 put_u16(dent + 0x1a, 0);
758 /* FAT32 high cluster bytes */
759 put_u16(dent + 0x14, 0);
762 put_u32(dent + 0x1c, 0);
767 ao_fat_dirent_init(uint8_t *dent, uint16_t entry, struct ao_fat_dirent *dirent)
769 memcpy(dirent->name, dent + 0x00, 11);
770 dirent->attr = dent[0x0b];
771 dirent->size = get_u32(dent+0x1c);
772 dirent->cluster = get_u16(dent+0x1a);
774 dirent->cluster |= (cluster_t) get_u16(dent + 0x14) << 16;
775 dirent->entry = entry;
779 * ao_fat_flush_fsinfo
781 * Write out any fsinfo changes to disk
785 ao_fat_flush_fsinfo(void)
798 fsinfo = ao_fat_sector_get(fsinfo_sector);
800 put_u32(fsinfo + 0x1e8, free_count);
801 put_u32(fsinfo + 0x1ec, next_free);
802 ao_fat_sector_put(fsinfo, 1);
813 * Flush any pending I/O to storage
819 if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
821 ao_fat_flush_fsinfo();
828 * Returns TRUE if the filesystem cannot take
835 if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
837 return filesystem_full;
843 * Open an existing file.
846 ao_fat_open(char name[11], uint8_t mode)
849 struct ao_fat_dirent dirent;
851 if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
855 return -AO_FAT_EMFILE;
857 while (ao_fat_readdir(&entry, &dirent)) {
858 if (!memcmp(name, dirent.name, 11)) {
859 if (AO_FAT_IS_DIR(dirent.attr))
860 return -AO_FAT_EISDIR;
861 if (!AO_FAT_IS_FILE(dirent.attr))
862 return -AO_FAT_EPERM;
863 if (mode > AO_FAT_OPEN_READ && (dirent.attr & AO_FAT_FILE_READ_ONLY))
864 return -AO_FAT_EACCESS;
865 ao_file_dirent = dirent;
866 ao_fat_set_offset(0);
868 return AO_FAT_SUCCESS;
871 return -AO_FAT_ENOENT;
877 * Open and truncate an existing file or
881 ao_fat_creat(char name[11])
887 if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
891 return -AO_FAT_EMFILE;
893 status = ao_fat_open(name, AO_FAT_OPEN_WRITE);
896 case -AO_FAT_SUCCESS:
897 status = ao_fat_set_size(0);
902 dent = ao_fat_root_get(entry);
905 if (ao_fat_root_extend(entry))
907 status = -AO_FAT_ENOSPC;
911 if (dent[0] == AO_FAT_DENT_EMPTY || dent[0] == AO_FAT_DENT_END) {
912 ao_fat_root_init(dent, name, AO_FAT_FILE_REGULAR);
913 ao_fat_dirent_init(dent, entry, &ao_file_dirent);
914 ao_fat_root_put(dent, entry, 1);
916 ao_fat_set_offset(0);
917 status = -AO_FAT_SUCCESS;
920 ao_fat_root_put(dent, entry, 0);
931 * Close the currently open file
937 return -AO_FAT_EBADF;
939 memset(&ao_file_dirent, '\0', sizeof (struct ao_fat_dirent));
945 return AO_FAT_SUCCESS;
951 * Map the sector pointed at by the current file offset
955 ao_fat_map_current(int len, cluster_offset_t *offsetp, cluster_offset_t *this_time)
957 cluster_offset_t offset;
961 offset = ao_file_offset & SECTOR_MASK;
962 sector = ao_fat_current_sector();
963 if (sector == 0xffffffff)
965 buf = ao_fat_sector_get(sector);
966 if (offset + len < SECTOR_SIZE)
969 *this_time = SECTOR_SIZE - offset;
980 ao_fat_read(void *dst, int len)
982 uint8_t *dst_b = dst;
983 cluster_offset_t this_time;
984 cluster_offset_t offset;
989 return -AO_FAT_EBADF;
991 if (ao_file_offset + len > ao_file_dirent.size)
992 len = ao_file_dirent.size - ao_file_offset;
998 buf = ao_fat_map_current(len, &offset, &this_time);
1003 memcpy(dst_b, buf + offset, this_time);
1004 ao_fat_sector_put(buf, 0);
1009 ao_fat_set_offset(ao_file_offset + this_time);
1017 * Write to the file, extended as necessary
1020 ao_fat_write(void *src, int len)
1022 uint8_t *src_b = src;
1028 if (!ao_file_opened)
1029 return -AO_FAT_EBADF;
1031 if (ao_file_offset + len > ao_file_dirent.size) {
1032 ret = ao_fat_set_size(ao_file_offset + len);
1038 buf = ao_fat_map_current(len, &offset, &this_time);
1043 memcpy(buf + offset, src_b, this_time);
1044 ao_fat_sector_put(buf, 1);
1049 ao_fat_set_offset(ao_file_offset + this_time);
1057 * Set the position for the next I/O operation
1058 * Note that this doesn't actually change the size
1059 * of the file if the requested position is beyond
1060 * the current file length, that would take a future
1064 ao_fat_seek(int32_t pos, uint8_t whence)
1066 uint32_t new_offset = ao_file_offset;
1068 if (!ao_file_opened)
1069 return -AO_FAT_EBADF;
1072 case AO_FAT_SEEK_SET:
1075 case AO_FAT_SEEK_CUR:
1078 case AO_FAT_SEEK_END:
1079 new_offset = ao_file_dirent.size + pos;
1082 ao_fat_set_offset(new_offset);
1083 return ao_file_offset;
1089 * Remove a file from the directory, marking
1090 * all clusters as free
1093 ao_fat_unlink(char name[11])
1096 struct ao_fat_dirent dirent;
1098 if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
1101 while (ao_fat_readdir(&entry, &dirent)) {
1102 if (memcmp(name, dirent.name, 11) == 0) {
1107 if (AO_FAT_IS_DIR(dirent.attr))
1108 return -AO_FAT_EISDIR;
1109 if (!AO_FAT_IS_FILE(dirent.attr))
1110 return -AO_FAT_EPERM;
1112 ao_fat_free_cluster_chain(dirent.cluster);
1113 next = ao_fat_root_get(dirent.entry + 1);
1114 if (next && next[0] != AO_FAT_DENT_END)
1115 delete = AO_FAT_DENT_EMPTY;
1117 delete = AO_FAT_DENT_END;
1119 ao_fat_root_put(next, dirent.entry + 1, 0);
1120 ent = ao_fat_root_get(dirent.entry);
1122 memset(ent, '\0', DIRENT_SIZE);
1124 ao_fat_root_put(ent, dirent.entry, 1);
1127 return AO_FAT_SUCCESS;
1130 return -AO_FAT_ENOENT;
1134 ao_fat_rename(char old[11], char new[11])
1140 ao_fat_readdir(uint16_t *entry, struct ao_fat_dirent *dirent)
1144 if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
1148 dent = ao_fat_root_get(*entry);
1152 if (dent[0] == AO_FAT_DENT_END) {
1153 ao_fat_root_put(dent, *entry, 0);
1156 if (dent[0] != AO_FAT_DENT_EMPTY && (dent[0xb] & 0xf) != 0xf) {
1157 ao_fat_dirent_init(dent, *entry, dirent);
1158 ao_fat_root_put(dent, *entry, 0);
1162 ao_fat_root_put(dent, *entry, 0);
1169 static const char *filesystem_errors[] = {
1170 [AO_FAT_FILESYSTEM_SUCCESS] = "FAT file system operating normally",
1171 [AO_FAT_FILESYSTEM_MBR_READ_FAILURE] = "MBR media read error",
1172 [AO_FAT_FILESYSTEM_INVALID_MBR_SIGNATURE] = "MBR signature invalid",
1173 [AO_FAT_FILESYSTEM_INVALID_PARTITION_TYPE] = "Unsupported paritition type",
1174 [AO_FAT_FILESYSTEM_ZERO_SIZED_PARTITION] = "Partition has zero sectors",
1175 [AO_FAT_FILESYSTEM_BOOT_READ_FAILURE] = "Boot block media read error",
1176 [AO_FAT_FILESYSTEM_INVALID_BOOT_SIGNATURE] = "Boot block signature invalid",
1177 [AO_FAT_FILESYSTEM_INVALID_SECTOR_SIZE] = "Sector size not 512",
1181 ao_fat_mbr_cmd(void)
1185 status = ao_fat_setup();
1186 if (status == AO_FAT_FILESYSTEM_SUCCESS) {
1187 printf ("partition type: %02x\n", partition_type);
1188 printf ("partition start: %08x\n", partition_start);
1190 printf ("partition end: %08x\n", partition_end);
1192 printf ("fat32: %d\n", fat32);
1193 printf ("sectors per cluster %d\n", sectors_per_cluster);
1194 printf ("reserved sectors %d\n", reserved_sector_count);
1195 printf ("number of FATs %d\n", number_fat);
1196 printf ("root entries %d\n", root_entries);
1197 printf ("sectors per fat %d\n", sectors_per_fat);
1199 printf ("fat start %d\n", fat_start);
1200 printf ("root start %d\n", root_start);
1201 printf ("data start %d\n", data_start);
1203 printf ("FAT filesystem not available: %s\n", filesystem_errors[status]);
1207 struct ao_fat_attr {
1212 static const struct ao_fat_attr ao_fat_attr[] = {
1213 { .bit = AO_FAT_FILE_READ_ONLY, .label = 'R' },
1214 { .bit = AO_FAT_FILE_HIDDEN, .label = 'H' },
1215 { .bit = AO_FAT_FILE_SYSTEM, .label = 'S' },
1216 { .bit = AO_FAT_FILE_VOLUME_LABEL, .label = 'V' },
1217 { .bit = AO_FAT_FILE_DIRECTORY, .label = 'D' },
1218 { .bit = AO_FAT_FILE_ARCHIVE, .label = 'A' },
1221 #define NUM_FAT_ATTR (sizeof (ao_fat_attr) / sizeof (ao_fat_attr[0]))
1224 ao_fat_list_cmd(void)
1227 struct ao_fat_dirent dirent;
1230 while (ao_fat_readdir(&entry, &dirent)) {
1231 for (i = 0; i < 8; i++)
1232 putchar(dirent.name[i]);
1235 putchar(dirent.name[i]);
1236 for (i = 0; i < NUM_FAT_ATTR; i++)
1237 putchar (dirent.attr & ao_fat_attr[i].bit ? ao_fat_attr[i].label : ' ');
1238 printf (" @%08x %d\n", dirent.cluster, dirent.size);
1243 ao_fat_parse_name(char name[11])
1250 while (ao_cmd_lex_c != '\n') {
1251 if (ao_cmd_lex_c == '.') {
1256 name[c++] = ao_cmd_lex_c;
1263 ao_fat_show_cmd(void)
1270 ao_fat_parse_name(name);
1271 if (name[0] == '\0') {
1272 ao_cmd_status = ao_cmd_syntax_error;
1276 status = ao_fat_open(name, AO_FAT_OPEN_READ);
1278 printf ("Open failed: %d\n", status);
1281 while ((cnt = ao_fat_read(buf, sizeof(buf))) > 0) {
1282 for (i = 0; i < cnt; i++)
1289 ao_fat_putchar(char c)
1294 ao_fat_write_cmd(void)
1302 ao_fat_parse_name(name);
1303 if (name[0] == '\0') {
1304 ao_cmd_status = ao_cmd_syntax_error;
1308 status = ao_fat_creat(name);
1310 printf ("Open failed: %d\n", status);
1314 while ((c = getchar()) != 4) {
1315 if (c == '\r') c = '\n';
1317 if (c == '\n') putchar ('\r');
1318 putchar(c); flush();
1320 if (ao_fat_write(&c, 1) != 1) {
1321 printf ("Write failure\n");
1328 static const struct ao_cmds ao_fat_cmds[] = {
1329 { ao_fat_mbr_cmd, "M\0Show FAT MBR and other info" },
1330 { ao_fat_list_cmd, "F\0List FAT directory" },
1331 { ao_fat_show_cmd, "S <name>\0Show FAT file" },
1332 { ao_fat_write_cmd, "W <name>\0Write FAT file (end with ^D)" },
1342 ao_cmd_register(&ao_fat_cmds[0]);