u-boot/fs/fat/fat_write.c
AKASHI Takahiro cb8af8af5b fs: fat: support write with non-zero offset
In this patch, all the necessary code for allowing for a file offset
at write is implemented. What plays a major roll here is get_set_cluster(),
which, in contrast to its counterpart, set_cluster(), only operates on
already-allocated clusters, overwriting with data.

So, with a file offset specified, set_contents() seeks and writes data
with set_get_cluster() until the end of a file, and, once it reaches
there, continues writing with set_cluster() for the rest.

Please note that a file will be trimmed as a result of write operation if
write ends before reaching file's end. This is an intended behavior
in order to maintain compatibility with the current interface.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
2018-09-23 21:55:29 +02:00

1185 lines
26 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* fat_write.c
*
* R/W (V)FAT 12/16/32 filesystem implementation by Donggeun Kim
*/
#include <common.h>
#include <command.h>
#include <config.h>
#include <fat.h>
#include <asm/byteorder.h>
#include <part.h>
#include <linux/ctype.h>
#include <div64.h>
#include <linux/math64.h>
#include "fat.c"
static void uppercase(char *str, int len)
{
int i;
for (i = 0; i < len; i++) {
*str = toupper(*str);
str++;
}
}
static int total_sector;
static int disk_write(__u32 block, __u32 nr_blocks, void *buf)
{
ulong ret;
if (!cur_dev)
return -1;
if (cur_part_info.start + block + nr_blocks >
cur_part_info.start + total_sector) {
printf("error: overflow occurs\n");
return -1;
}
ret = blk_dwrite(cur_dev, cur_part_info.start + block, nr_blocks, buf);
if (nr_blocks && ret == 0)
return -1;
return ret;
}
/*
* 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;
strcpy(s_name, filename);
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);
}
/*
* Write fat buffer into block device
*/
static int flush_dirty_fat_buffer(fsdata *mydata)
{
int getsize = FATBUFBLOCKS;
__u32 fatlength = mydata->fatlength;
__u8 *bufptr = mydata->fatbuf;
__u32 startblock = mydata->fatbufnum * FATBUFBLOCKS;
debug("debug: evicting %d, dirty: %d\n", mydata->fatbufnum,
(int)mydata->fat_dirty);
if ((!mydata->fat_dirty) || (mydata->fatbufnum == -1))
return 0;
/* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
if (startblock + getsize > fatlength)
getsize = fatlength - startblock;
startblock += mydata->fat_sect;
/* Write FAT buf */
if (disk_write(startblock, getsize, bufptr) < 0) {
debug("error: writing FAT blocks\n");
return -1;
}
if (mydata->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;
}
}
mydata->fat_dirty = 0;
return 0;
}
/*
* 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 flush_dir_table(fat_itr *itr);
/*
* Fill dir_slot entries with appropriate name, id, and attr
* 'itr' will point to a next entry
*/
static int
fill_dir_slot(fat_itr *itr, const char *l_name)
{
__u8 temp_dir_slot_buffer[MAX_LFN_SLOT * sizeof(dir_slot)];
dir_slot *slotptr = (dir_slot *)temp_dir_slot_buffer;
__u8 counter = 0, checksum;
int idx = 0, ret;
/* Get short file name checksum value */
checksum = mkcksum(itr->dent->name, itr->dent->ext);
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) {
memcpy(itr->dent, slotptr, sizeof(dir_slot));
slotptr--;
counter--;
if (!fat_itr_next(itr))
if (!itr->dent && !itr->is_root && flush_dir_table(itr))
return -1;
}
if (!itr->dent && !itr->is_root)
/*
* don't care return value here because we have already
* finished completing an entry with name, only ending up
* no more entry left
*/
flush_dir_table(itr);
return 0;
}
/*
* Set the entry at index 'entry' in a FAT (12/16/32) table.
*/
static int set_fatent_value(fsdata *mydata, __u32 entry, __u32 entry_value)
{
__u32 bufnum, offset, off16;
__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 -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;
/* Cap length if fatlength is not a multiple of FATBUFBLOCKS */
if (startblock + getsize > fatlength)
getsize = fatlength - startblock;
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
startblock += mydata->fat_sect;
if (disk_read(startblock, getsize, bufptr) < 0) {
debug("Error reading FAT blocks\n");
return -1;
}
mydata->fatbufnum = bufnum;
}
/* Mark as dirty */
mydata->fat_dirty = 1;
/* 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;
case 12:
off16 = (offset * 3) / 4;
switch (offset & 0x3) {
case 0:
val1 = cpu_to_le16(entry_value) & 0xfff;
((__u16 *)mydata->fatbuf)[off16] &= ~0xfff;
((__u16 *)mydata->fatbuf)[off16] |= val1;
break;
case 1:
val1 = cpu_to_le16(entry_value) & 0xf;
val2 = (cpu_to_le16(entry_value) >> 4) & 0xff;
((__u16 *)mydata->fatbuf)[off16] &= ~0xf000;
((__u16 *)mydata->fatbuf)[off16] |= (val1 << 12);
((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xff;
((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
break;
case 2:
val1 = cpu_to_le16(entry_value) & 0xff;
val2 = (cpu_to_le16(entry_value) >> 8) & 0xf;
((__u16 *)mydata->fatbuf)[off16] &= ~0xff00;
((__u16 *)mydata->fatbuf)[off16] |= (val1 << 8);
((__u16 *)mydata->fatbuf)[off16 + 1] &= ~0xf;
((__u16 *)mydata->fatbuf)[off16 + 1] |= val2;
break;
case 3:
val1 = cpu_to_le16(entry_value) & 0xfff;
((__u16 *)mydata->fatbuf)[off16] &= ~0xfff0;
((__u16 *)mydata->fatbuf)[off16] |= (val1 << 4);
break;
default:
break;
}
break;
default:
return -1;
}
return 0;
}
/*
* Determine the next free cluster after 'entry' in a FAT (12/16/32) table
* and link it to 'entry'. EOC marker is not set on returned entry.
*/
static __u32 determine_fatent(fsdata *mydata, __u32 entry)
{
__u32 next_fat, next_entry = entry + 1;
while (1) {
next_fat = get_fatent(mydata, next_entry);
if (next_fat == 0) {
/* found free entry, link to entry */
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)
{
__u32 idx = 0;
__u32 startsect;
int ret;
if (clustnum > 0)
startsect = clust_to_sect(mydata, clustnum);
else
startsect = mydata->rootdir_sect;
debug("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) {
memcpy(tmpbuf, buffer, mydata->sect_size);
ret = disk_write(startsect++, 1, tmpbuf);
if (ret != 1) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
buffer += mydata->sect_size;
size -= mydata->sect_size;
}
} else if (size >= mydata->sect_size) {
idx = size / mydata->sect_size;
ret = disk_write(startsect, idx, buffer);
if (ret != idx) {
debug("Error writing 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);
memcpy(tmpbuf, buffer, size);
ret = disk_write(startsect, 1, tmpbuf);
if (ret != 1) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
}
return 0;
}
static __u8 tmpbuf_cluster[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
/*
* Read and modify data on existing and consecutive cluster blocks
*/
static int
get_set_cluster(fsdata *mydata, __u32 clustnum, loff_t pos, __u8 *buffer,
loff_t size, loff_t *gotsize)
{
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
__u32 startsect;
loff_t wsize;
int clustcount, i, ret;
*gotsize = 0;
if (!size)
return 0;
assert(pos < bytesperclust);
startsect = clust_to_sect(mydata, clustnum);
debug("clustnum: %d, startsect: %d, pos: %lld\n",
clustnum, startsect, pos);
/* partial write at beginning */
if (pos) {
wsize = min(bytesperclust - pos, size);
ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(tmpbuf_cluster + pos, buffer, wsize);
ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
size -= wsize;
buffer += wsize;
*gotsize += wsize;
startsect += mydata->clust_size;
if (!size)
return 0;
}
/* full-cluster write */
if (size >= bytesperclust) {
clustcount = lldiv(size, bytesperclust);
if (!((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1))) {
wsize = clustcount * bytesperclust;
ret = disk_write(startsect,
clustcount * mydata->clust_size,
buffer);
if (ret != clustcount * mydata->clust_size) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
size -= wsize;
buffer += wsize;
*gotsize += wsize;
startsect += clustcount * mydata->clust_size;
} else {
for (i = 0; i < clustcount; i++) {
memcpy(tmpbuf_cluster, buffer, bytesperclust);
ret = disk_write(startsect,
mydata->clust_size,
tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error writing data (got %d)\n",
ret);
return -1;
}
size -= bytesperclust;
buffer += bytesperclust;
*gotsize += bytesperclust;
startsect += mydata->clust_size;
}
}
}
/* partial write at end */
if (size) {
wsize = size;
ret = disk_read(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(tmpbuf_cluster, buffer, wsize);
ret = disk_write(startsect, mydata->clust_size, tmpbuf_cluster);
if (ret != mydata->clust_size) {
debug("Error writing data (got %d)\n", ret);
return -1;
}
size -= wsize;
buffer += wsize;
*gotsize += wsize;
}
assert(!size);
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(mydata, entry);
if (fat_val == 0)
break;
entry++;
}
return entry;
}
/*
* Write directory entries in itr's buffer to block device
*/
static int flush_dir_table(fat_itr *itr)
{
fsdata *mydata = itr->fsdata;
int dir_newclust = 0;
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
if (set_cluster(mydata, itr->clust, itr->block, bytesperclust) != 0) {
printf("error: writing directory entry\n");
return -1;
}
dir_newclust = find_empty_cluster(mydata);
set_fatent_value(mydata, itr->clust, 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);
else if (mydata->fatsize == 12)
set_fatent_value(mydata, dir_newclust, 0xff8);
itr->clust = dir_newclust;
itr->next_clust = dir_newclust;
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
memset(itr->block, 0x00, bytesperclust);
itr->dent = (dir_entry *)itr->block;
itr->last_cluster = 1;
itr->remaining = bytesperclust / sizeof(dir_entry) - 1;
return 0;
}
/*
* Set empty cluster from 'entry' to the end of a file
*/
static int clear_fatent(fsdata *mydata, __u32 entry)
{
__u32 fat_val;
while (!CHECK_CLUST(entry, mydata->fatsize)) {
fat_val = get_fatent(mydata, entry);
if (fat_val != 0)
set_fatent_value(mydata, entry, 0);
else
break;
entry = fat_val;
}
/* Flush fat buffer */
if (flush_dirty_fat_buffer(mydata) < 0)
return -1;
return 0;
}
/*
* Set start cluster in directory entry
*/
static void set_start_cluster(const fsdata *mydata, dir_entry *dentptr,
__u32 start_cluster)
{
if (mydata->fatsize == 32)
dentptr->starthi =
cpu_to_le16((start_cluster & 0xffff0000) >> 16);
dentptr->start = cpu_to_le16(start_cluster & 0xffff);
}
/*
* 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, loff_t size)
{
__u32 startsect, sect_num, offset;
if (clustnum > 0)
startsect = clust_to_sect(mydata, clustnum);
else
startsect = mydata->rootdir_sect;
sect_num = div_u64_rem(size, mydata->sect_size, &offset);
if (offset != 0)
sect_num++;
if (startsect + sect_num > total_sector)
return -1;
return 0;
}
/*
* Write at most 'maxsize' bytes from 'buffer' into
* the file associated with 'dentptr'
* Update the number of bytes written in *gotsize and return 0
* or return -1 on fatal errors.
*/
static int
set_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos, __u8 *buffer,
loff_t maxsize, loff_t *gotsize)
{
loff_t filesize;
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
__u32 curclust = START(dentptr);
__u32 endclust = 0, newclust = 0;
loff_t cur_pos, offset, actsize, wsize;
*gotsize = 0;
filesize = pos + maxsize;
debug("%llu bytes\n", filesize);
if (!filesize) {
if (!curclust)
return 0;
if (!CHECK_CLUST(curclust, mydata->fatsize) ||
IS_LAST_CLUST(curclust, mydata->fatsize)) {
clear_fatent(mydata, curclust);
set_start_cluster(mydata, dentptr, 0);
return 0;
}
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return -1;
}
if (!curclust) {
assert(pos == 0);
goto set_clusters;
}
/* go to cluster at pos */
cur_pos = bytesperclust;
while (1) {
if (pos <= cur_pos)
break;
if (IS_LAST_CLUST(curclust, mydata->fatsize))
break;
newclust = get_fatent(mydata, curclust);
if (!IS_LAST_CLUST(newclust, mydata->fatsize) &&
CHECK_CLUST(newclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return -1;
}
cur_pos += bytesperclust;
curclust = newclust;
}
if (IS_LAST_CLUST(curclust, mydata->fatsize)) {
assert(pos == cur_pos);
goto set_clusters;
}
assert(pos < cur_pos);
cur_pos -= bytesperclust;
/* overwrite */
assert(IS_LAST_CLUST(curclust, mydata->fatsize) ||
!CHECK_CLUST(curclust, mydata->fatsize));
while (1) {
/* search for allocated consecutive clusters */
actsize = bytesperclust;
endclust = curclust;
while (1) {
if (filesize <= (cur_pos + actsize))
break;
newclust = get_fatent(mydata, endclust);
if (IS_LAST_CLUST(newclust, mydata->fatsize))
break;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return -1;
}
actsize += bytesperclust;
endclust = newclust;
}
/* overwrite to <curclust..endclust> */
if (pos < cur_pos)
offset = 0;
else
offset = pos - cur_pos;
wsize = min(cur_pos + actsize, filesize) - pos;
if (get_set_cluster(mydata, curclust, offset,
buffer, wsize, &actsize)) {
printf("Error get-and-setting cluster\n");
return -1;
}
buffer += wsize;
*gotsize += wsize;
cur_pos += offset + wsize;
if (filesize <= cur_pos)
break;
/* CHECK: newclust = get_fatent(mydata, endclust); */
if (IS_LAST_CLUST(newclust, mydata->fatsize))
/* no more clusters */
break;
curclust = newclust;
}
if (filesize <= cur_pos) {
/* no more write */
newclust = get_fatent(mydata, endclust);
if (!IS_LAST_CLUST(newclust, mydata->fatsize)) {
/* truncate the rest */
clear_fatent(mydata, newclust);
/* Mark end of file in FAT */
if (mydata->fatsize == 12)
newclust = 0xfff;
else if (mydata->fatsize == 16)
newclust = 0xffff;
else if (mydata->fatsize == 32)
newclust = 0xfffffff;
set_fatent_value(mydata, endclust, newclust);
}
return 0;
}
curclust = endclust;
filesize -= cur_pos;
assert(!(cur_pos % bytesperclust));
set_clusters:
/* allocate and write */
assert(!pos);
/* Assure that curclust is valid */
if (!curclust) {
curclust = find_empty_cluster(mydata);
set_start_cluster(mydata, dentptr, curclust);
} else {
newclust = get_fatent(mydata, curclust);
if (IS_LAST_CLUST(newclust, mydata->fatsize)) {
newclust = determine_fatent(mydata, curclust);
set_fatent_value(mydata, curclust, newclust);
curclust = newclust;
} else {
debug("error: something wrong\n");
return -1;
}
}
/* TODO: already partially written */
if (check_overflow(mydata, curclust, filesize)) {
printf("Error: no space left: %llu\n", filesize);
return -1;
}
actsize = bytesperclust;
endclust = curclust;
do {
/* search for consecutive clusters */
while (actsize < filesize) {
newclust = determine_fatent(mydata, endclust);
if ((newclust - 1) != endclust)
/* write to <curclust..endclust> */
goto getit;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("newclust: 0x%x\n", newclust);
debug("Invalid FAT entry\n");
return 0;
}
endclust = newclust;
actsize += bytesperclust;
}
/* set remaining bytes */
actsize = filesize;
if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
debug("error: writing cluster\n");
return -1;
}
*gotsize += actsize;
/* Mark end of file in FAT */
if (mydata->fatsize == 12)
newclust = 0xfff;
else if (mydata->fatsize == 16)
newclust = 0xffff;
else if (mydata->fatsize == 32)
newclust = 0xfffffff;
set_fatent_value(mydata, endclust, newclust);
return 0;
getit:
if (set_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
debug("error: writing cluster\n");
return -1;
}
*gotsize += actsize;
filesize -= actsize;
buffer += actsize;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("newclust: 0x%x\n", newclust);
debug("Invalid FAT entry\n");
return 0;
}
actsize = bytesperclust;
curclust = endclust = newclust;
} while (1);
return 0;
}
/*
* Fill dir_entry
*/
static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
const char *filename, __u32 start_cluster, __u32 size, __u8 attr)
{
set_start_cluster(mydata, dentptr, start_cluster);
dentptr->size = cpu_to_le32(size);
dentptr->attr = attr;
set_name(dentptr, filename);
}
/*
* 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(fat_itr *itr, char *filename)
{
int match = 0;
while (fat_itr_next(itr)) {
/* check both long and short name: */
if (!strcasecmp(filename, itr->name))
match = 1;
else if (itr->name != itr->s_name &&
!strcasecmp(filename, itr->s_name))
match = 1;
if (!match)
continue;
if (itr->dent->name[0] == '\0')
return NULL;
else
return itr->dent;
}
if (!itr->dent && !itr->is_root && flush_dir_table(itr))
/* indicate that allocating dent failed */
itr->dent = NULL;
return NULL;
}
static int split_filename(char *filename, char **dirname, char **basename)
{
char *p, *last_slash, *last_slash_cont;
again:
p = filename;
last_slash = NULL;
last_slash_cont = NULL;
while (*p) {
if (ISDIRDELIM(*p)) {
last_slash = p;
last_slash_cont = p;
/* continuous slashes */
while (ISDIRDELIM(*p))
last_slash_cont = p++;
if (!*p)
break;
}
p++;
}
if (last_slash) {
if (last_slash_cont == (filename + strlen(filename) - 1)) {
/* remove trailing slashes */
*last_slash = '\0';
goto again;
}
if (last_slash == filename) {
/* avoid ""(null) directory */
*dirname = "/";
} else {
*last_slash = '\0';
*dirname = filename;
}
*last_slash_cont = '\0';
*basename = last_slash_cont + 1;
} else {
*dirname = "/"; /* root by default */
*basename = filename;
}
return 0;
}
static int normalize_longname(char *l_filename, const char *filename)
{
const char *p, legal[] = "!#$%&\'()-.@^`_{}~";
char c;
int name_len;
/* Check that the filename is valid */
for (p = filename; p < filename + strlen(filename); p++) {
c = *p;
if (('0' <= c) && (c <= '9'))
continue;
if (('A' <= c) && (c <= 'Z'))
continue;
if (('a' <= c) && (c <= 'z'))
continue;
if (strchr(legal, c))
continue;
/* extended code */
if ((0x80 <= c) && (c <= 0xff))
continue;
return -1;
}
/* Normalize it */
name_len = strlen(filename);
if (name_len >= VFAT_MAXLEN_BYTES)
/* should return an error? */
name_len = VFAT_MAXLEN_BYTES - 1;
memcpy(l_filename, filename, name_len);
l_filename[name_len] = 0; /* terminate the string */
downcase(l_filename, INT_MAX);
return 0;
}
int file_fat_write_at(const char *filename, loff_t pos, void *buffer,
loff_t size, loff_t *actwrite)
{
dir_entry *retdent;
fsdata datablock = { .fatbuf = NULL, };
fsdata *mydata = &datablock;
fat_itr *itr = NULL;
int ret = -1;
char *filename_copy, *parent, *basename;
char l_filename[VFAT_MAXLEN_BYTES];
debug("writing %s\n", filename);
filename_copy = strdup(filename);
if (!filename_copy)
return -ENOMEM;
split_filename(filename_copy, &parent, &basename);
if (!strlen(basename)) {
ret = -EINVAL;
goto exit;
}
filename = basename;
if (normalize_longname(l_filename, filename)) {
printf("FAT: illegal filename (%s)\n", filename);
ret = -EINVAL;
goto exit;
}
itr = malloc_cache_aligned(sizeof(fat_itr));
if (!itr) {
ret = -ENOMEM;
goto exit;
}
ret = fat_itr_root(itr, &datablock);
if (ret)
goto exit;
total_sector = datablock.total_sect;
ret = fat_itr_resolve(itr, parent, TYPE_DIR);
if (ret) {
printf("%s: doesn't exist (%d)\n", parent, ret);
goto exit;
}
retdent = find_directory_entry(itr, l_filename);
if (retdent) {
if (fat_itr_isdir(itr)) {
ret = -EISDIR;
goto exit;
}
/* A file exists */
if (pos == -1)
/* Append to the end */
pos = FAT2CPU32(retdent->size);
if (pos > retdent->size) {
/* No hole allowed */
ret = -EINVAL;
goto exit;
}
/* Update file size in a directory entry */
retdent->size = cpu_to_le32(pos + size);
} else {
/* Create a new file */
if (itr->is_root) {
/* root dir cannot have "." or ".." */
if (!strcmp(l_filename, ".") ||
!strcmp(l_filename, "..")) {
ret = -EINVAL;
goto exit;
}
}
if (!itr->dent) {
printf("Error: allocating new dir entry\n");
ret = -EIO;
goto exit;
}
if (pos) {
/* No hole allowed */
ret = -EINVAL;
goto exit;
}
memset(itr->dent, 0, sizeof(*itr->dent));
/* Set short name to set alias checksum field in dir_slot */
set_name(itr->dent, filename);
if (fill_dir_slot(itr, filename)) {
ret = -EIO;
goto exit;
}
/* Set attribute as archive for regular file */
fill_dentry(itr->fsdata, itr->dent, filename, 0, size, 0x20);
retdent = itr->dent;
}
ret = set_contents(mydata, retdent, pos, buffer, size, actwrite);
if (ret < 0) {
printf("Error: writing contents\n");
ret = -EIO;
goto exit;
}
debug("attempt to write 0x%llx bytes\n", *actwrite);
/* Flush fat buffer */
ret = flush_dirty_fat_buffer(mydata);
if (ret) {
printf("Error: flush fat buffer\n");
ret = -EIO;
goto exit;
}
/* Write directory table to device */
ret = set_cluster(mydata, itr->clust, itr->block,
mydata->clust_size * mydata->sect_size);
if (ret) {
printf("Error: writing directory entry\n");
ret = -EIO;
}
exit:
free(filename_copy);
free(mydata->fatbuf);
free(itr);
return ret;
}
int file_fat_write(const char *filename, void *buffer, loff_t offset,
loff_t maxsize, loff_t *actwrite)
{
return file_fat_write_at(filename, offset, buffer, maxsize, actwrite);
}