u-boot/fs/fat/fat_write.c
Benoît Thébaudeau 1170e634dd FAT: Make it possible to read from any file position
When storage devices contain files larger than the embedded RAM, it is
useful to be able to read these files by chunks, e.g. for a software
update to the embedded NAND Flash from an external storage device (USB
stick, SD card, etc.).

Hence, this patch makes it possible by adding a new FAT API to read
files from a given position. This patch also adds this feature to the
fatload command.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Wolfgang Denk <wd@denx.de>
Signed-off-by: Tom Rini <trini@ti.com>
2012-09-26 11:11:32 -07:00

1098 lines
25 KiB
C

/*
* fat_write.c
*
* R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <command.h>
#include <config.h>
#include <fat.h>
#include <asm/byteorder.h>
#include <part.h>
#include "fat.c"
static void uppercase(char *str, int len)
{
int i;
for (i = 0; i < len; i++) {
TOUPPER(*str);
str++;
}
}
static int total_sector;
static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
{
if (!cur_dev || !cur_dev->block_write)
return -1;
if (cur_part_info.start + block + nr_blocks >
cur_part_info.start + total_sector) {
printf("error: overflow occurs\n");
return -1;
}
return cur_dev->block_write(cur_dev->dev,
cur_part_info.start + block, nr_blocks, buf);
}
/*
* Set short name in directory entry
*/
static void set_name(dir_entry *dirent, const char *filename)
{
char s_name[VFAT_MAXLEN_BYTES];
char *period;
int period_location, len, i, ext_num;
if (filename == NULL)
return;
len = strlen(filename);
if (len == 0)
return;
memcpy(s_name, filename, len);
uppercase(s_name, len);
period = strchr(s_name, '.');
if (period == NULL) {
period_location = len;
ext_num = 0;
} else {
period_location = period - s_name;
ext_num = len - period_location - 1;
}
/* Pad spaces when the length of file name is shorter than eight */
if (period_location < 8) {
memcpy(dirent->name, s_name, period_location);
for (i = period_location; i < 8; i++)
dirent->name[i] = ' ';
} else if (period_location == 8) {
memcpy(dirent->name, s_name, period_location);
} else {
memcpy(dirent->name, s_name, 6);
dirent->name[6] = '~';
dirent->name[7] = '1';
}
if (ext_num < 3) {
memcpy(dirent->ext, s_name + period_location + 1, ext_num);
for (i = ext_num; i < 3; i++)
dirent->ext[i] = ' ';
} else
memcpy(dirent->ext, s_name + period_location + 1, 3);
debug("name : %s\n", dirent->name);
debug("ext : %s\n", dirent->ext);
}
static __u8 num_of_fats;
/*
* Write fat buffer into block device
*/
static int flush_fat_buffer(fsdata *mydata)
{
int getsize = FATBUFBLOCKS;
__u32 fatlength = mydata->fatlength;
__u8 *bufptr = mydata->fatbuf;
__u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
fatlength *= mydata->sect_size;
startblock += mydata->fat_sect;
if (getsize > fatlength)
getsize = fatlength;
/* Write FAT buf */
if (disk_write(startblock, getsize, bufptr) < 0) {
debug("error: writing FAT blocks\n");
return -1;
}
if (num_of_fats == 2) {
/* Update corresponding second FAT blocks */
startblock += mydata->fatlength;
if (disk_write(startblock, getsize, bufptr) < 0) {
debug("error: writing second FAT blocks\n");
return -1;
}
}
return 0;
}
/*
* Get the entry at index 'entry' in a FAT (12/16/32) table.
* On failure 0x00 is returned.
* When bufnum is changed, write back the previous fatbuf to the disk.
*/
static __u32 get_fatent_value(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) {
int getsize = FATBUFBLOCKS;
__u8 *bufptr = mydata->fatbuf;
__u32 fatlength = mydata->fatlength;
__u32 startblock = bufnum * FATBUFBLOCKS;
if (getsize > fatlength)
getsize = fatlength;
fatlength *= mydata->sect_size; /* We want it in bytes now */
startblock += mydata->fat_sect; /* Offset from start of disk */
/* Write back the fatbuf to the disk */
if (mydata->fatbufnum != -1) {
if (flush_fat_buffer(mydata) < 0)
return -1;
}
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, entry: %08x, offset: %04x\n",
mydata->fatsize, ret, entry, offset);
return ret;
}
#ifdef CONFIG_SUPPORT_VFAT
/*
* Set the file name information from 'name' into 'slotptr',
*/
static int str2slot(dir_slot *slotptr, const char *name, int *idx)
{
int j, end_idx = 0;
for (j = 0; j <= 8; j += 2) {
if (name[*idx] == 0x00) {
slotptr->name0_4[j] = 0;
slotptr->name0_4[j + 1] = 0;
end_idx++;
goto name0_4;
}
slotptr->name0_4[j] = name[*idx];
(*idx)++;
end_idx++;
}
for (j = 0; j <= 10; j += 2) {
if (name[*idx] == 0x00) {
slotptr->name5_10[j] = 0;
slotptr->name5_10[j + 1] = 0;
end_idx++;
goto name5_10;
}
slotptr->name5_10[j] = name[*idx];
(*idx)++;
end_idx++;
}
for (j = 0; j <= 2; j += 2) {
if (name[*idx] == 0x00) {
slotptr->name11_12[j] = 0;
slotptr->name11_12[j + 1] = 0;
end_idx++;
goto name11_12;
}
slotptr->name11_12[j] = name[*idx];
(*idx)++;
end_idx++;
}
if (name[*idx] == 0x00)
return 1;
return 0;
/* Not used characters are filled with 0xff 0xff */
name0_4:
for (; end_idx < 5; end_idx++) {
slotptr->name0_4[end_idx * 2] = 0xff;
slotptr->name0_4[end_idx * 2 + 1] = 0xff;
}
end_idx = 5;
name5_10:
end_idx -= 5;
for (; end_idx < 6; end_idx++) {
slotptr->name5_10[end_idx * 2] = 0xff;
slotptr->name5_10[end_idx * 2 + 1] = 0xff;
}
end_idx = 11;
name11_12:
end_idx -= 11;
for (; end_idx < 2; end_idx++) {
slotptr->name11_12[end_idx * 2] = 0xff;
slotptr->name11_12[end_idx * 2 + 1] = 0xff;
}
return 1;
}
static int is_next_clust(fsdata *mydata, dir_entry *dentptr);
static void flush_dir_table(fsdata *mydata, dir_entry **dentptr);
/*
* Fill dir_slot entries with appropriate name, id, and attr
* The real directory entry is returned by 'dentptr'
*/
static void
fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
{
dir_slot *slotptr = (dir_slot *)get_contents_vfatname_block;
__u8 counter = 0, checksum;
int idx = 0, ret;
char s_name[16];
/* Get short file name and checksum value */
strncpy(s_name, (*dentptr)->name, 16);
checksum = mkcksum(s_name);
do {
memset(slotptr, 0x00, sizeof(dir_slot));
ret = str2slot(slotptr, l_name, &idx);
slotptr->id = ++counter;
slotptr->attr = ATTR_VFAT;
slotptr->alias_checksum = checksum;
slotptr++;
} while (ret == 0);
slotptr--;
slotptr->id |= LAST_LONG_ENTRY_MASK;
while (counter >= 1) {
if (is_next_clust(mydata, *dentptr)) {
/* A new cluster is allocated for directory table */
flush_dir_table(mydata, dentptr);
}
memcpy(*dentptr, slotptr, sizeof(dir_slot));
(*dentptr)++;
slotptr--;
counter--;
}
if (is_next_clust(mydata, *dentptr)) {
/* A new cluster is allocated for directory table */
flush_dir_table(mydata, dentptr);
}
}
static __u32 dir_curclust;
/*
* 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'
* If additional adjacent cluster for directory entries is read into memory,
* then 'get_contents_vfatname_block' is copied into 'get_dentfromdir_block' and
* the location of the real directory entry is returned by 'retdent'
* Return 0 on success, -1 otherwise.
*/
static int
get_long_file_name(fsdata *mydata, int curclust, __u8 *cluster,
dir_entry **retdent, char *l_name)
{
dir_entry *realdent;
dir_slot *slotptr = (dir_slot *)(*retdent);
dir_slot *slotptr2 = NULL;
__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, cur_position = 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) {
if (curclust == 0)
return -1;
curclust = get_fatent_value(mydata, dir_curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return -1;
}
dir_curclust = curclust;
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 */
*retdent = realdent;
if (slotptr2) {
memcpy(get_dentfromdir_block, get_contents_vfatname_block,
mydata->clust_size * mydata->sect_size);
cur_position = (__u8 *)realdent - get_contents_vfatname_block;
*retdent = (dir_entry *) &get_dentfromdir_block[cur_position];
}
return 0;
}
#endif
/*
* Set the entry at index 'entry' in a FAT (16/32) table.
*/
static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
{
__u32 bufnum, offset;
switch (mydata->fatsize) {
case 32:
bufnum = entry / FAT32BUFSIZE;
offset = entry - bufnum * FAT32BUFSIZE;
break;
case 16:
bufnum = entry / FAT16BUFSIZE;
offset = entry - bufnum * FAT16BUFSIZE;
break;
default:
/* Unsupported FAT size */
return -1;
}
/* Read a new block of FAT entries into the cache. */
if (bufnum != mydata->fatbufnum) {
int getsize = FATBUFBLOCKS;
__u8 *bufptr = mydata->fatbuf;
__u32 fatlength = mydata->fatlength;
__u32 startblock = bufnum * FATBUFBLOCKS;
fatlength *= mydata->sect_size;
startblock += mydata->fat_sect;
if (getsize > fatlength)
getsize = fatlength;
if (mydata->fatbufnum != -1) {
if (flush_fat_buffer(mydata) < 0)
return -1;
}
if (disk_read(startblock, getsize, bufptr) < 0) {
debug("Error reading FAT blocks\n");
return -1;
}
mydata->fatbufnum = bufnum;
}
/* Set the actual entry */
switch (mydata->fatsize) {
case 32:
((__u32 *) mydata->fatbuf)[offset] = cpu_to_le32(entry_value);
break;
case 16:
((__u16 *) mydata->fatbuf)[offset] = cpu_to_le16(entry_value);
break;
default:
return -1;
}
return 0;
}
/*
* Determine the entry value at index 'entry' in a FAT (16/32) table
*/
static __u32 determine_fatent(fsdata *mydata, __u32 entry)
{
__u32 next_fat, next_entry = entry + 1;
while (1) {
next_fat = get_fatent_value(mydata, next_entry);
if (next_fat == 0) {
set_fatent_value(mydata, entry, next_entry);
break;
}
next_entry++;
}
debug("FAT%d: entry: %08x, entry_value: %04x\n",
mydata->fatsize, entry, next_entry);
return next_entry;
}
/*
* Write at most 'size' bytes from 'buffer' into the specified cluster.
* Return 0 on success, -1 otherwise.
*/
static int
set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
unsigned long size)
{
int idx = 0;
__u32 startsect;
if (clustnum > 0)
startsect = mydata->data_begin +
clustnum * mydata->clust_size;
else
startsect = mydata->rootdir_sect;
debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
debug("Error writing data\n");
return -1;
}
if (size % mydata->sect_size) {
__u8 tmpbuf[mydata->sect_size];
idx = size / mydata->sect_size;
buffer += idx * mydata->sect_size;
memcpy(tmpbuf, buffer, size % mydata->sect_size);
if (disk_write(startsect + idx, 1, tmpbuf) < 0) {
debug("Error writing data\n");
return -1;
}
return 0;
}
return 0;
}
/*
* Find the first empty cluster
*/
static int find_empty_cluster(fsdata *mydata)
{
__u32 fat_val, entry = 3;
while (1) {
fat_val = get_fatent_value(mydata, entry);
if (fat_val == 0)
break;
entry++;
}
return entry;
}
/*
* Write directory entries in 'get_dentfromdir_block' to block device
*/
static void flush_dir_table(fsdata *mydata, dir_entry **dentptr)
{
int dir_newclust = 0;
if (set_cluster(mydata, dir_curclust,
get_dentfromdir_block,
mydata->clust_size * mydata->sect_size) != 0) {
printf("error: wrinting directory entry\n");
return;
}
dir_newclust = find_empty_cluster(mydata);
set_fatent_value(mydata, dir_curclust, dir_newclust);
if (mydata->fatsize == 32)
set_fatent_value(mydata, dir_newclust, 0xffffff8);
else if (mydata->fatsize == 16)
set_fatent_value(mydata, dir_newclust, 0xfff8);
dir_curclust = dir_newclust;
if (flush_fat_buffer(mydata) < 0)
return;
memset(get_dentfromdir_block, 0x00,
mydata->clust_size * mydata->sect_size);
*dentptr = (dir_entry *) get_dentfromdir_block;
}
/*
* Set empty cluster from 'entry' to the end of a file
*/
static int clear_fatent(fsdata *mydata, __u32 entry)
{
__u32 fat_val;
while (1) {
fat_val = get_fatent_value(mydata, entry);
if (fat_val != 0)
set_fatent_value(mydata, entry, 0);
else
break;
if (fat_val == 0xfffffff || fat_val == 0xffff)
break;
entry = fat_val;
}
/* Flush fat buffer */
if (flush_fat_buffer(mydata) < 0)
return -1;
return 0;
}
/*
* Write at most 'maxsize' bytes from 'buffer' into
* the file associated with 'dentptr'
* Return the number of bytes read or -1 on fatal errors.
*/
static int
set_contents(fsdata *mydata, dir_entry *dentptr, __u8 *buffer,
unsigned long maxsize)
{
unsigned long filesize = FAT2CPU32(dentptr->size), gotsize = 0;
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
__u32 curclust = START(dentptr);
__u32 endclust = 0, newclust = 0;
unsigned long actsize;
debug("Filesize: %ld bytes\n", filesize);
if (maxsize > 0 && filesize > maxsize)
filesize = maxsize;
debug("%ld bytes\n", filesize);
actsize = bytesperclust;
endclust = curclust;
do {
/* search for consecutive clusters */
while (actsize < filesize) {
newclust = determine_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 gotsize;
}
endclust = newclust;
actsize += bytesperclust;
}
/* actsize >= file size */
actsize -= bytesperclust;
/* set remaining clusters */
if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
debug("error: writing cluster\n");
return -1;
}
/* set remaining bytes */
gotsize += (int)actsize;
filesize -= actsize;
buffer += actsize;
actsize = filesize;
if (set_cluster(mydata, endclust, buffer, (int)actsize) != 0) {
debug("error: writing cluster\n");
return -1;
}
gotsize += actsize;
/* Mark end of file in FAT */
if (mydata->fatsize == 16)
newclust = 0xffff;
else if (mydata->fatsize == 32)
newclust = 0xfffffff;
set_fatent_value(mydata, endclust, newclust);
return gotsize;
getit:
if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
debug("error: writing cluster\n");
return -1;
}
gotsize += (int)actsize;
filesize -= actsize;
buffer += actsize;
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return gotsize;
}
actsize = bytesperclust;
curclust = endclust = newclust;
} while (1);
}
/*
* Fill dir_entry
*/
static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
{
if (mydata->fatsize == 32)
dentptr->starthi =
cpu_to_le16((start_cluster & 0xffff0000) >> 16);
dentptr->start = cpu_to_le16(start_cluster & 0xffff);
dentptr->size = cpu_to_le32(size);
dentptr->attr = attr;
set_name(dentptr, filename);
}
/*
* Check whether adding a file makes the file system to
* exceed the size of the block device
* Return -1 when overflow occurs, otherwise return 0
*/
static int check_overflow(fsdata *mydata, __u32 clustnum, unsigned long size)
{
__u32 startsect, sect_num;
if (clustnum > 0) {
startsect = mydata->data_begin +
clustnum * mydata->clust_size;
} else {
startsect = mydata->rootdir_sect;
}
sect_num = size / mydata->sect_size;
if (size % mydata->sect_size)
sect_num++;
if (startsect + sect_num > cur_part_info.start + total_sector)
return -1;
return 0;
}
/*
* Check if adding several entries exceed one cluster boundary
*/
static int is_next_clust(fsdata *mydata, dir_entry *dentptr)
{
int cur_position;
cur_position = (__u8 *)dentptr - get_dentfromdir_block;
if (cur_position >= mydata->clust_size * mydata->sect_size)
return 1;
else
return 0;
}
static dir_entry *empty_dentptr;
/*
* Find a directory entry based on filename or start cluster number
* If the directory entry is not found,
* the new position for writing a directory entry will be returned
*/
static dir_entry *find_directory_entry(fsdata *mydata, int startsect,
char *filename, dir_entry *retdent, __u32 start)
{
__u32 curclust = (startsect - mydata->data_begin) / mydata->clust_size;
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) {
printf("Error: reading directory block\n");
return NULL;
}
dentptr = (dir_entry *)get_dentfromdir_block;
dir_curclust = curclust;
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++;
if (is_next_clust(mydata, dentptr))
break;
continue;
}
if ((dentptr->attr & ATTR_VOLUME)) {
#ifdef CONFIG_SUPPORT_VFAT
if ((dentptr->attr & ATTR_VFAT) &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
get_long_file_name(mydata, curclust,
get_dentfromdir_block,
&dentptr, l_name);
debug("vfatname: |%s|\n", l_name);
} else
#endif
{
/* Volume label or VFAT entry */
dentptr++;
if (is_next_clust(mydata, dentptr))
break;
continue;
}
}
if (dentptr->name[0] == 0) {
debug("Dentname == NULL - %d\n", i);
empty_dentptr = dentptr;
return NULL;
}
get_name(dentptr, s_name);
if (strcmp(filename, s_name)
&& strcmp(filename, l_name)) {
debug("Mismatch: |%s|%s|\n",
s_name, l_name);
dentptr++;
if (is_next_clust(mydata, dentptr))
break;
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 dentptr;
}
curclust = get_fatent_value(mydata, dir_curclust);
if ((curclust >= 0xffffff8) || (curclust >= 0xfff8)) {
empty_dentptr = dentptr;
return NULL;
}
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return NULL;
}
}
return NULL;
}
static int do_fat_write(const char *filename, void *buffer,
unsigned long size)
{
dir_entry *dentptr, *retdent;
__u32 startsect;
__u32 start_cluster;
boot_sector bs;
volume_info volinfo;
fsdata datablock;
fsdata *mydata = &datablock;
int cursect;
int ret = -1, name_len;
char l_filename[VFAT_MAXLEN_BYTES];
int write_size = size;
dir_curclust = 0;
if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
debug("error: reading boot sector\n");
return -1;
}
total_sector = bs.total_sect;
if (total_sector == 0)
total_sector = cur_part_info.size;
if (mydata->fatsize == 32)
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;
num_of_fats = bs.fats;
mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
mydata->clust_size = bs.cluster_size;
if (mydata->fatsize == 32) {
mydata->data_begin = mydata->rootdir_sect -
(mydata->clust_size * 2);
} else {
int rootdir_size;
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->fatbuf = malloc(FATBUFSIZE);
if (mydata->fatbuf == NULL) {
debug("Error: allocating memory\n");
return -1;
}
if (disk_read(cursect,
(mydata->fatsize == 32) ?
(mydata->clust_size) :
PREFETCH_BLOCKS, do_fat_read_at_block) < 0) {
debug("Error: reading rootdir block\n");
goto exit;
}
dentptr = (dir_entry *) do_fat_read_at_block;
name_len = strlen(filename);
if (name_len >= VFAT_MAXLEN_BYTES)
name_len = VFAT_MAXLEN_BYTES - 1;
memcpy(l_filename, filename, name_len);
l_filename[name_len] = 0; /* terminate the string */
downcase(l_filename);
startsect = mydata->rootdir_sect;
retdent = find_directory_entry(mydata, startsect,
l_filename, dentptr, 0);
if (retdent) {
/* Update file size and start_cluster in a directory entry */
retdent->size = cpu_to_le32(size);
start_cluster = FAT2CPU16(retdent->start);
if (mydata->fatsize == 32)
start_cluster |=
(FAT2CPU16(retdent->starthi) << 16);
ret = check_overflow(mydata, start_cluster, size);
if (ret) {
printf("Error: %ld overflow\n", size);
goto exit;
}
ret = clear_fatent(mydata, start_cluster);
if (ret) {
printf("Error: clearing FAT entries\n");
goto exit;
}
ret = set_contents(mydata, retdent, buffer, size);
if (ret < 0) {
printf("Error: writing contents\n");
goto exit;
}
write_size = ret;
debug("attempt to write 0x%x bytes\n", write_size);
/* Flush fat buffer */
ret = flush_fat_buffer(mydata);
if (ret) {
printf("Error: flush fat buffer\n");
goto exit;
}
/* Write directory table to device */
ret = set_cluster(mydata, dir_curclust,
get_dentfromdir_block,
mydata->clust_size * mydata->sect_size);
if (ret) {
printf("Error: writing directory entry\n");
goto exit;
}
} else {
/* Set short name to set alias checksum field in dir_slot */
set_name(empty_dentptr, filename);
fill_dir_slot(mydata, &empty_dentptr, filename);
ret = start_cluster = find_empty_cluster(mydata);
if (ret < 0) {
printf("Error: finding empty cluster\n");
goto exit;
}
ret = check_overflow(mydata, start_cluster, size);
if (ret) {
printf("Error: %ld overflow\n", size);
goto exit;
}
/* Set attribute as archieve for regular file */
fill_dentry(mydata, empty_dentptr, filename,
start_cluster, size, 0x20);
ret = set_contents(mydata, empty_dentptr, buffer, size);
if (ret < 0) {
printf("Error: writing contents\n");
goto exit;
}
write_size = ret;
debug("attempt to write 0x%x bytes\n", write_size);
/* Flush fat buffer */
ret = flush_fat_buffer(mydata);
if (ret) {
printf("Error: flush fat buffer\n");
goto exit;
}
/* Write directory table to device */
ret = set_cluster(mydata, dir_curclust,
get_dentfromdir_block,
mydata->clust_size * mydata->sect_size);
if (ret) {
printf("Error: writing directory entry\n");
goto exit;
}
}
exit:
free(mydata->fatbuf);
return ret < 0 ? ret : write_size;
}
int file_fat_write(const char *filename, void *buffer, unsigned long maxsize)
{
printf("writing %s\n", filename);
return do_fat_write(filename, buffer, maxsize);
}