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u-boot/fs/fat/fat.c
Stefan Brüns 3c0ed9c3a5 fs/fat: Do not write unmodified fat entries to disk 
The code caches 6 sectors of the FAT. On FAT traversal, the old contents
needs to be flushed to disk, but only if any FAT entries had been modified.
Explicitly flag the buffer on modification.

Currently, creating a new file traverses the whole FAT up to the first
free cluster and rewrites the on-disk blocks.

Signed-off-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
2016-09-23 08:55:56 -04:00

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/*
* fat.c
*
* R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
*
* 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
* 2003-03-10 - kharris@nexus-tech.net - ported to uboot
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <blk.h>
#include <config.h>
#include <exports.h>
#include <fat.h>
#include <asm/byteorder.h>
#include <part.h>
#include <malloc.h>
#include <memalign.h>
#include <linux/compiler.h>
#include <linux/ctype.h>
#ifdef CONFIG_SUPPORT_VFAT
static const int vfat_enabled = 1;
#else
static const int vfat_enabled = 0;
#endif
/*
* Convert a string to lowercase.
*/
static void downcase(char *str)
{
while (*str != '\0') {
*str = tolower(*str);
str++;
}
}
static struct blk_desc *cur_dev;
static disk_partition_t cur_part_info;
#define DOS_BOOT_MAGIC_OFFSET 0x1fe
#define DOS_FS_TYPE_OFFSET 0x36
#define DOS_FS32_TYPE_OFFSET 0x52
static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
{
ulong ret;
if (!cur_dev)
return -1;
ret = blk_dread(cur_dev, cur_part_info.start + block, nr_blocks, buf);
if (nr_blocks && ret == 0)
return -1;
return ret;
}
int fat_set_blk_dev(struct blk_desc *dev_desc, disk_partition_t *info)
{
ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
cur_dev = dev_desc;
cur_part_info = *info;
/* Make sure it has a valid FAT header */
if (disk_read(0, 1, buffer) != 1) {
cur_dev = NULL;
return -1;
}
/* Check if it's actually a DOS volume */
if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
cur_dev = NULL;
return -1;
}
/* Check for FAT12/FAT16/FAT32 filesystem */
if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
return 0;
if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
return 0;
cur_dev = NULL;
return -1;
}
int fat_register_device(struct blk_desc *dev_desc, int part_no)
{
disk_partition_t info;
/* First close any currently found FAT filesystem */
cur_dev = NULL;
/* Read the partition table, if present */
if (part_get_info(dev_desc, part_no, &info)) {
if (part_no != 0) {
printf("** Partition %d not valid on device %d **\n",
part_no, dev_desc->devnum);
return -1;
}
info.start = 0;
info.size = dev_desc->lba;
info.blksz = dev_desc->blksz;
info.name[0] = 0;
info.type[0] = 0;
info.bootable = 0;
#ifdef CONFIG_PARTITION_UUIDS
info.uuid[0] = 0;
#endif
}
return fat_set_blk_dev(dev_desc, &info);
}
/*
* Get the first occurence of a directory delimiter ('/' or '\') in a string.
* Return index into string if found, -1 otherwise.
*/
static int dirdelim(char *str)
{
char *start = str;
while (*str != '\0') {
if (ISDIRDELIM(*str))
return str - start;
str++;
}
return -1;
}
/*
* Extract zero terminated short name from a directory entry.
*/
static void get_name(dir_entry *dirent, char *s_name)
{
char *ptr;
memcpy(s_name, dirent->name, 8);
s_name[8] = '\0';
ptr = s_name;
while (*ptr && *ptr != ' ')
ptr++;
if (dirent->ext[0] && dirent->ext[0] != ' ') {
*ptr = '.';
ptr++;
memcpy(ptr, dirent->ext, 3);
ptr[3] = '\0';
while (*ptr && *ptr != ' ')
ptr++;
}
*ptr = '\0';
if (*s_name == DELETED_FLAG)
*s_name = '\0';
else if (*s_name == aRING)
*s_name = DELETED_FLAG;
downcase(s_name);
}
/*
* Get the entry at index 'entry' in a FAT (12/16/32) table.
* On failure 0x00 is returned.
*/
static __u32 get_fatent(fsdata *mydata, __u32 entry)
{
__u32 bufnum;
__u32 off16, offset;
__u32 ret = 0x00;
__u16 val1, val2;
switch (mydata->fatsize) {
case 32:
bufnum = entry / FAT32BUFSIZE;
offset = entry - bufnum * FAT32BUFSIZE;
break;
case 16:
bufnum = entry / FAT16BUFSIZE;
offset = entry - bufnum * FAT16BUFSIZE;
break;
case 12:
bufnum = entry / FAT12BUFSIZE;
offset = entry - bufnum * FAT12BUFSIZE;
break;
default:
/* Unsupported FAT size */
return ret;
}
debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
mydata->fatsize, entry, entry, offset, offset);
/* Read a new block of FAT entries into the cache. */
if (bufnum != mydata->fatbufnum) {
__u32 getsize = FATBUFBLOCKS;
__u8 *bufptr = mydata->fatbuf;
__u32 fatlength = mydata->fatlength;
__u32 startblock = bufnum * FATBUFBLOCKS;
if (startblock + getsize > fatlength)
getsize = fatlength - startblock;
startblock += mydata->fat_sect; /* Offset from start of disk */
if (disk_read(startblock, getsize, bufptr) < 0) {
debug("Error reading FAT blocks\n");
return ret;
}
mydata->fatbufnum = bufnum;
}
/* Get the actual entry from the table */
switch (mydata->fatsize) {
case 32:
ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
break;
case 16:
ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
break;
case 12:
off16 = (offset * 3) / 4;
switch (offset & 0x3) {
case 0:
ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
ret &= 0xfff;
break;
case 1:
val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
val1 &= 0xf000;
val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
val2 &= 0x00ff;
ret = (val2 << 4) | (val1 >> 12);
break;
case 2:
val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
val1 &= 0xff00;
val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
val2 &= 0x000f;
ret = (val2 << 8) | (val1 >> 8);
break;
case 3:
ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
ret = (ret & 0xfff0) >> 4;
break;
default:
break;
}
break;
}
debug("FAT%d: ret: %08x, offset: %04x\n",
mydata->fatsize, ret, offset);
return ret;
}
/*
* Read at most 'size' bytes from the specified cluster into 'buffer'.
* Return 0 on success, -1 otherwise.
*/
static int
get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
{
__u32 idx = 0;
__u32 startsect;
int ret;
if (clustnum > 0) {
startsect = mydata->data_begin +
clustnum * mydata->clust_size;
} else {
startsect = mydata->rootdir_sect;
}
debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
printf("FAT: Misaligned buffer address (%p)\n", buffer);
while (size >= mydata->sect_size) {
ret = disk_read(startsect++, 1, tmpbuf);
if (ret != 1) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(buffer, tmpbuf, mydata->sect_size);
buffer += mydata->sect_size;
size -= mydata->sect_size;
}
} else {
idx = size / mydata->sect_size;
ret = disk_read(startsect, idx, buffer);
if (ret != idx) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
startsect += idx;
idx *= mydata->sect_size;
buffer += idx;
size -= idx;
}
if (size) {
ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
ret = disk_read(startsect, 1, tmpbuf);
if (ret != 1) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(buffer, tmpbuf, size);
}
return 0;
}
/*
* Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
* into 'buffer'.
* Update the number of bytes read in *gotsize or return -1 on fatal errors.
*/
__u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
__u8 *buffer, loff_t maxsize, loff_t *gotsize)
{
loff_t filesize = FAT2CPU32(dentptr->size);
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
__u32 curclust = START(dentptr);
__u32 endclust, newclust;
loff_t actsize;
*gotsize = 0;
debug("Filesize: %llu bytes\n", filesize);
if (pos >= filesize) {
debug("Read position past EOF: %llu\n", pos);
return 0;
}
if (maxsize > 0 && filesize > pos + maxsize)
filesize = pos + maxsize;
debug("%llu bytes\n", filesize);
actsize = bytesperclust;
/* go to cluster at pos */
while (actsize <= pos) {
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return 0;
}
actsize += bytesperclust;
}
/* actsize > pos */
actsize -= bytesperclust;
filesize -= actsize;
pos -= actsize;
/* align to beginning of next cluster if any */
if (pos) {
actsize = min(filesize, (loff_t)bytesperclust);
if (get_cluster(mydata, curclust, get_contents_vfatname_block,
(int)actsize) != 0) {
printf("Error reading cluster\n");
return -1;
}
filesize -= actsize;
actsize -= pos;
memcpy(buffer, get_contents_vfatname_block + pos, actsize);
*gotsize += actsize;
if (!filesize)
return 0;
buffer += actsize;
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return 0;
}
}
actsize = bytesperclust;
endclust = curclust;
do {
/* search for consecutive clusters */
while (actsize < filesize) {
newclust = get_fatent(mydata, endclust);
if ((newclust - 1) != endclust)
goto getit;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", newclust);
debug("Invalid FAT entry\n");
return 0;
}
endclust = newclust;
actsize += bytesperclust;
}
/* get remaining bytes */
actsize = filesize;
if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
printf("Error reading cluster\n");
return -1;
}
*gotsize += actsize;
return 0;
getit:
if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
printf("Error reading cluster\n");
return -1;
}
*gotsize += (int)actsize;
filesize -= actsize;
buffer += actsize;
curclust = get_fatent(mydata, endclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return 0;
}
actsize = bytesperclust;
endclust = curclust;
} while (1);
}
/*
* Extract the file name information from 'slotptr' into 'l_name',
* starting at l_name[*idx].
* Return 1 if terminator (zero byte) is found, 0 otherwise.
*/
static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
{
int j;
for (j = 0; j <= 8; j += 2) {
l_name[*idx] = slotptr->name0_4[j];
if (l_name[*idx] == 0x00)
return 1;
(*idx)++;
}
for (j = 0; j <= 10; j += 2) {
l_name[*idx] = slotptr->name5_10[j];
if (l_name[*idx] == 0x00)
return 1;
(*idx)++;
}
for (j = 0; j <= 2; j += 2) {
l_name[*idx] = slotptr->name11_12[j];
if (l_name[*idx] == 0x00)
return 1;
(*idx)++;
}
return 0;
}
/*
* Extract the full long filename starting at 'retdent' (which is really
* a slot) into 'l_name'. If successful also copy the real directory entry
* into 'retdent'
* Return 0 on success, -1 otherwise.
*/
static int
get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
dir_entry *retdent, char *l_name)
{
dir_entry *realdent;
dir_slot *slotptr = (dir_slot *)retdent;
__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
PREFETCH_BLOCKS :
mydata->clust_size);
__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
int idx = 0;
if (counter > VFAT_MAXSEQ) {
debug("Error: VFAT name is too long\n");
return -1;
}
while ((__u8 *)slotptr < buflimit) {
if (counter == 0)
break;
if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
return -1;
slotptr++;
counter--;
}
if ((__u8 *)slotptr >= buflimit) {
dir_slot *slotptr2;
if (curclust == 0)
return -1;
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return -1;
}
if (get_cluster(mydata, curclust, get_contents_vfatname_block,
mydata->clust_size * mydata->sect_size) != 0) {
debug("Error: reading directory block\n");
return -1;
}
slotptr2 = (dir_slot *)get_contents_vfatname_block;
while (counter > 0) {
if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
& 0xff) != counter)
return -1;
slotptr2++;
counter--;
}
/* Save the real directory entry */
realdent = (dir_entry *)slotptr2;
while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
slotptr2--;
slot2str(slotptr2, l_name, &idx);
}
} else {
/* Save the real directory entry */
realdent = (dir_entry *)slotptr;
}
do {
slotptr--;
if (slot2str(slotptr, l_name, &idx))
break;
} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
l_name[idx] = '\0';
if (*l_name == DELETED_FLAG)
*l_name = '\0';
else if (*l_name == aRING)
*l_name = DELETED_FLAG;
downcase(l_name);
/* Return the real directory entry */
memcpy(retdent, realdent, sizeof(dir_entry));
return 0;
}
/* Calculate short name checksum */
static __u8 mkcksum(const char name[8], const char ext[3])
{
int i;
__u8 ret = 0;
for (i = 0; i < 8; i++)
ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
for (i = 0; i < 3; i++)
ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
return ret;
}
/*
* Get the directory entry associated with 'filename' from the directory
* starting at 'startsect'
*/
__u8 get_dentfromdir_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
char *filename, dir_entry *retdent,
int dols)
{
__u16 prevcksum = 0xffff;
__u32 curclust = START(retdent);
int files = 0, dirs = 0;
debug("get_dentfromdir: %s\n", filename);
while (1) {
dir_entry *dentptr;
int i;
if (get_cluster(mydata, curclust, get_dentfromdir_block,
mydata->clust_size * mydata->sect_size) != 0) {
debug("Error: reading directory block\n");
return NULL;
}
dentptr = (dir_entry *)get_dentfromdir_block;
for (i = 0; i < DIRENTSPERCLUST; i++) {
char s_name[14], l_name[VFAT_MAXLEN_BYTES];
l_name[0] = '\0';
if (dentptr->name[0] == DELETED_FLAG) {
dentptr++;
continue;
}
if ((dentptr->attr & ATTR_VOLUME)) {
if (vfat_enabled &&
(dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
prevcksum = ((dir_slot *)dentptr)->alias_checksum;
get_vfatname(mydata, curclust,
get_dentfromdir_block,
dentptr, l_name);
if (dols) {
int isdir;
char dirc;
int doit = 0;
isdir = (dentptr->attr & ATTR_DIR);
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (l_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
l_name,
dirc);
} else {
printf(" %s%c\n",
l_name,
dirc);
}
}
dentptr++;
continue;
}
debug("vfatname: |%s|\n", l_name);
} else {
/* Volume label or VFAT entry */
dentptr++;
continue;
}
}
if (dentptr->name[0] == 0) {
if (dols) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
}
debug("Dentname == NULL - %d\n", i);
return NULL;
}
if (vfat_enabled) {
__u8 csum = mkcksum(dentptr->name, dentptr->ext);
if (dols && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;
}
}
get_name(dentptr, s_name);
if (dols) {
int isdir = (dentptr->attr & ATTR_DIR);
char dirc;
int doit = 0;
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (s_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
s_name, dirc);
} else {
printf(" %s%c\n",
s_name, dirc);
}
}
dentptr++;
continue;
}
if (strcmp(filename, s_name)
&& strcmp(filename, l_name)) {
debug("Mismatch: |%s|%s|\n", s_name, l_name);
dentptr++;
continue;
}
memcpy(retdent, dentptr, sizeof(dir_entry));
debug("DentName: %s", s_name);
debug(", start: 0x%x", START(dentptr));
debug(", size: 0x%x %s\n",
FAT2CPU32(dentptr->size),
(dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
return retdent;
}
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return NULL;
}
}
return NULL;
}
/*
* Read boot sector and volume info from a FAT filesystem
*/
static int
read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
{
__u8 *block;
volume_info *vistart;
int ret = 0;
if (cur_dev == NULL) {
debug("Error: no device selected\n");
return -1;
}
block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
if (block == NULL) {
debug("Error: allocating block\n");
return -1;
}
if (disk_read(0, 1, block) < 0) {
debug("Error: reading block\n");
goto fail;
}
memcpy(bs, block, sizeof(boot_sector));
bs->reserved = FAT2CPU16(bs->reserved);
bs->fat_length = FAT2CPU16(bs->fat_length);
bs->secs_track = FAT2CPU16(bs->secs_track);
bs->heads = FAT2CPU16(bs->heads);
bs->total_sect = FAT2CPU32(bs->total_sect);
/* FAT32 entries */
if (bs->fat_length == 0) {
/* Assume FAT32 */
bs->fat32_length = FAT2CPU32(bs->fat32_length);
bs->flags = FAT2CPU16(bs->flags);
bs->root_cluster = FAT2CPU32(bs->root_cluster);
bs->info_sector = FAT2CPU16(bs->info_sector);
bs->backup_boot = FAT2CPU16(bs->backup_boot);
vistart = (volume_info *)(block + sizeof(boot_sector));
*fatsize = 32;
} else {
vistart = (volume_info *)&(bs->fat32_length);
*fatsize = 0;
}
memcpy(volinfo, vistart, sizeof(volume_info));
if (*fatsize == 32) {
if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
goto exit;
} else {
if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
*fatsize = 12;
goto exit;
}
if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
*fatsize = 16;
goto exit;
}
}
debug("Error: broken fs_type sign\n");
fail:
ret = -1;
exit:
free(block);
return ret;
}
__u8 do_fat_read_at_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, int dols, int dogetsize, loff_t *size)
{
char fnamecopy[2048];
boot_sector bs;
volume_info volinfo;
fsdata datablock;
fsdata *mydata = &datablock;
dir_entry *dentptr = NULL;
__u16 prevcksum = 0xffff;
char *subname = "";
__u32 cursect;
int idx, isdir = 0;
int files = 0, dirs = 0;
int ret = -1;
int firsttime;
__u32 root_cluster = 0;
__u32 read_blk;
int rootdir_size = 0;
int buffer_blk_cnt;
int do_read;
__u8 *dir_ptr;
if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
debug("Error: reading boot sector\n");
return -1;
}
if (mydata->fatsize == 32) {
root_cluster = bs.root_cluster;
mydata->fatlength = bs.fat32_length;
} else {
mydata->fatlength = bs.fat_length;
}
mydata->fat_sect = bs.reserved;
cursect = mydata->rootdir_sect
= mydata->fat_sect + mydata->fatlength * bs.fats;
mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
mydata->clust_size = bs.cluster_size;
if (mydata->sect_size != cur_part_info.blksz) {
printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
mydata->sect_size, cur_part_info.blksz);
return -1;
}
if (mydata->fatsize == 32) {
mydata->data_begin = mydata->rootdir_sect -
(mydata->clust_size * 2);
} else {
rootdir_size = ((bs.dir_entries[1] * (int)256 +
bs.dir_entries[0]) *
sizeof(dir_entry)) /
mydata->sect_size;
mydata->data_begin = mydata->rootdir_sect +
rootdir_size -
(mydata->clust_size * 2);
}
mydata->fatbufnum = -1;
mydata->fat_dirty = 0;
mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
if (mydata->fatbuf == NULL) {
debug("Error: allocating memory\n");
return -1;
}
if (vfat_enabled)
debug("VFAT Support enabled\n");
debug("FAT%d, fat_sect: %d, fatlength: %d\n",
mydata->fatsize, mydata->fat_sect, mydata->fatlength);
debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
"Data begins at: %d\n",
root_cluster,
mydata->rootdir_sect,
mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
mydata->clust_size);
/* "cwd" is always the root... */
while (ISDIRDELIM(*filename))
filename++;
/* Make a copy of the filename and convert it to lowercase */
strcpy(fnamecopy, filename);
downcase(fnamecopy);
root_reparse:
if (*fnamecopy == '\0') {
if (!dols)
goto exit;
dols = LS_ROOT;
} else if ((idx = dirdelim(fnamecopy)) >= 0) {
isdir = 1;
fnamecopy[idx] = '\0';
subname = fnamecopy + idx + 1;
/* Handle multiple delimiters */
while (ISDIRDELIM(*subname))
subname++;
} else if (dols) {
isdir = 1;
}
buffer_blk_cnt = 0;
firsttime = 1;
while (1) {
int i;
if (mydata->fatsize == 32 || firsttime) {
dir_ptr = do_fat_read_at_block;
firsttime = 0;
} else {
/**
* FAT16 sector buffer modification:
* Each loop, the second buffered block is moved to
* the buffer begin, and two next sectors are read
* next to the previously moved one. So the sector
* buffer keeps always 3 sectors for fat16.
* And the current sector is the buffer second sector
* beside the "firsttime" read, when it is the first one.
*
* PREFETCH_BLOCKS is 2 for FAT16 == loop[0:1]
* n = computed root dir sector
* loop | cursect-1 | cursect | cursect+1 |
* 0 | sector n+0 | sector n+1 | none |
* 1 | none | sector n+0 | sector n+1 |
* 0 | sector n+1 | sector n+2 | sector n+3 |
* 1 | sector n+3 | ...
*/
dir_ptr = (do_fat_read_at_block + mydata->sect_size);
memcpy(do_fat_read_at_block, dir_ptr, mydata->sect_size);
}
do_read = 1;
if (mydata->fatsize == 32 && buffer_blk_cnt)
do_read = 0;
if (do_read) {
read_blk = (mydata->fatsize == 32) ?
mydata->clust_size : PREFETCH_BLOCKS;
debug("FAT read(sect=%d, cnt:%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
cursect, read_blk, mydata->clust_size, DIRENTSPERBLOCK);
if (disk_read(cursect, read_blk, dir_ptr) < 0) {
debug("Error: reading rootdir block\n");
goto exit;
}
dentptr = (dir_entry *)dir_ptr;
}
for (i = 0; i < DIRENTSPERBLOCK; i++) {
char s_name[14], l_name[VFAT_MAXLEN_BYTES];
__u8 csum;
l_name[0] = '\0';
if (dentptr->name[0] == DELETED_FLAG) {
dentptr++;
continue;
}
if (vfat_enabled)
csum = mkcksum(dentptr->name, dentptr->ext);
if (dentptr->attr & ATTR_VOLUME) {
if (vfat_enabled &&
(dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
prevcksum =
((dir_slot *)dentptr)->alias_checksum;
get_vfatname(mydata,
root_cluster,
dir_ptr,
dentptr, l_name);
if (dols == LS_ROOT) {
char dirc;
int doit = 0;
int isdir =
(dentptr->attr & ATTR_DIR);
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (l_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
l_name,
dirc);
} else {
printf(" %s%c\n",
l_name,
dirc);
}
}
dentptr++;
continue;
}
debug("Rootvfatname: |%s|\n",
l_name);
} else {
/* Volume label or VFAT entry */
dentptr++;
continue;
}
} else if (dentptr->name[0] == 0) {
debug("RootDentname == NULL - %d\n", i);
if (dols == LS_ROOT) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
ret = 0;
}
goto exit;
}
else if (vfat_enabled &&
dols == LS_ROOT && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;
}
get_name(dentptr, s_name);
if (dols == LS_ROOT) {
int isdir = (dentptr->attr & ATTR_DIR);
char dirc;
int doit = 0;
if (isdir) {
dirc = '/';
if (s_name[0] != 0) {
dirs++;
doit = 1;
}
} else {
dirc = ' ';
if (s_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
s_name, dirc);
} else {
printf(" %s%c\n",
s_name, dirc);
}
}
dentptr++;
continue;
}
if (strcmp(fnamecopy, s_name)
&& strcmp(fnamecopy, l_name)) {
debug("RootMismatch: |%s|%s|\n", s_name,
l_name);
dentptr++;
continue;
}
if (isdir && !(dentptr->attr & ATTR_DIR))
goto exit;
debug("RootName: %s", s_name);
debug(", start: 0x%x", START(dentptr));
debug(", size: 0x%x %s\n",
FAT2CPU32(dentptr->size),
isdir ? "(DIR)" : "");
goto rootdir_done; /* We got a match */
}
debug("END LOOP: buffer_blk_cnt=%d clust_size=%d\n", buffer_blk_cnt,
mydata->clust_size);
/*
* On FAT32 we must fetch the FAT entries for the next
* root directory clusters when a cluster has been
* completely processed.
*/
++buffer_blk_cnt;
int rootdir_end = 0;
if (mydata->fatsize == 32) {
if (buffer_blk_cnt == mydata->clust_size) {
int nxtsect = 0;
int nxt_clust = 0;
nxt_clust = get_fatent(mydata, root_cluster);
rootdir_end = CHECK_CLUST(nxt_clust, 32);
nxtsect = mydata->data_begin +
(nxt_clust * mydata->clust_size);
root_cluster = nxt_clust;
cursect = nxtsect;
buffer_blk_cnt = 0;
}
} else {
if (buffer_blk_cnt == PREFETCH_BLOCKS)
buffer_blk_cnt = 0;
rootdir_end = (++cursect - mydata->rootdir_sect >=
rootdir_size);
}
/* If end of rootdir reached */
if (rootdir_end) {
if (dols == LS_ROOT) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
*size = 0;
}
goto exit;
}
}
rootdir_done:
firsttime = 1;
while (isdir) {
int startsect = mydata->data_begin
+ START(dentptr) * mydata->clust_size;
dir_entry dent;
char *nextname = NULL;
dent = *dentptr;
dentptr = &dent;
idx = dirdelim(subname);
if (idx >= 0) {
subname[idx] = '\0';
nextname = subname + idx + 1;
/* Handle multiple delimiters */
while (ISDIRDELIM(*nextname))
nextname++;
if (dols && *nextname == '\0')
firsttime = 0;
} else {
if (dols && firsttime) {
firsttime = 0;
} else {
isdir = 0;
}
}
if (get_dentfromdir(mydata, startsect, subname, dentptr,
isdir ? 0 : dols) == NULL) {
if (dols && !isdir)
*size = 0;
goto exit;
}
if (isdir && !(dentptr->attr & ATTR_DIR))
goto exit;
/*
* If we are looking for a directory, and found a directory
* type entry, and the entry is for the root directory (as
* denoted by a cluster number of 0), jump back to the start
* of the function, since at least on FAT12/16, the root dir
* lives in a hard-coded location and needs special handling
* to parse, rather than simply following the cluster linked
* list in the FAT, like other directories.
*/
if (isdir && (dentptr->attr & ATTR_DIR) && !START(dentptr)) {
/*
* Modify the filename to remove the prefix that gets
* back to the root directory, so the initial root dir
* parsing code can continue from where we are without
* confusion.
*/
strcpy(fnamecopy, nextname ?: "");
/*
* Set up state the same way as the function does when
* first started. This is required for the root dir
* parsing code operates in its expected environment.
*/
subname = "";
cursect = mydata->rootdir_sect;
isdir = 0;
goto root_reparse;
}
if (idx >= 0)
subname = nextname;
}
if (dogetsize) {
*size = FAT2CPU32(dentptr->size);
ret = 0;
} else {
ret = get_contents(mydata, dentptr, pos, buffer, maxsize, size);
}
debug("Size: %u, got: %llu\n", FAT2CPU32(dentptr->size), *size);
exit:
free(mydata->fatbuf);
return ret;
}
int do_fat_read(const char *filename, void *buffer, loff_t maxsize, int dols,
loff_t *actread)
{
return do_fat_read_at(filename, 0, buffer, maxsize, dols, 0, actread);
}
int file_fat_detectfs(void)
{
boot_sector bs;
volume_info volinfo;
int fatsize;
char vol_label[12];
if (cur_dev == NULL) {
printf("No current device\n");
return 1;
}
#if defined(CONFIG_CMD_IDE) || \
defined(CONFIG_CMD_SATA) || \
defined(CONFIG_SCSI) || \
defined(CONFIG_CMD_USB) || \
defined(CONFIG_MMC)
printf("Interface: ");
switch (cur_dev->if_type) {
case IF_TYPE_IDE:
printf("IDE");
break;
case IF_TYPE_SATA:
printf("SATA");
break;
case IF_TYPE_SCSI:
printf("SCSI");
break;
case IF_TYPE_ATAPI:
printf("ATAPI");
break;
case IF_TYPE_USB:
printf("USB");
break;
case IF_TYPE_DOC:
printf("DOC");
break;
case IF_TYPE_MMC:
printf("MMC");
break;
default:
printf("Unknown");
}
printf("\n Device %d: ", cur_dev->devnum);
dev_print(cur_dev);
#endif
if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
printf("\nNo valid FAT fs found\n");
return 1;
}
memcpy(vol_label, volinfo.volume_label, 11);
vol_label[11] = '\0';
volinfo.fs_type[5] = '\0';
printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
return 0;
}
int file_fat_ls(const char *dir)
{
loff_t size;
return do_fat_read(dir, NULL, 0, LS_YES, &size);
}
int fat_exists(const char *filename)
{
int ret;
loff_t size;
ret = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, &size);
return ret == 0;
}
int fat_size(const char *filename, loff_t *size)
{
return do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, size);
}
int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, loff_t *actread)
{
printf("reading %s\n", filename);
return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO, 0,
actread);
}
int file_fat_read(const char *filename, void *buffer, int maxsize)
{
loff_t actread;
int ret;
ret = file_fat_read_at(filename, 0, buffer, maxsize, &actread);
if (ret)
return ret;
else
return actread;
}
int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
loff_t *actread)
{
int ret;
ret = file_fat_read_at(filename, offset, buf, len, actread);
if (ret)
printf("** Unable to read file %s **\n", filename);
return ret;
}
void fat_close(void)
{
}
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