libfat/source/fatfile.c

816 lines
23 KiB
C

/*
fatfile.c
Functions used by the newlib disc stubs to interface with
this library
Copyright (c) 2006 Michael "Chishm" Chisholm
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
2006-07-11 - Chishm
* Original release
2006-07-17 - Chishm
* Made all path inputs const char*
* Added _FAT_rename_r
2006-08-02 - Chishm
* Fixed _FAT_seek_r
2006-08-13 - Chishm
* Moved all externally visible directory related functions to fatdir
*/
#include "fatfile.h"
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <unistd.h>
#include "cache.h"
#include "file_allocation_table.h"
#include "bit_ops.h"
#include "filetime.h"
int _FAT_open_r (struct _reent *r, void *fileStruct, const char *path, int flags, int mode) {
PARTITION* partition = NULL;
bool fileExists;
DIR_ENTRY dirEntry;
const char* pathEnd;
u32 dirCluster;
FILE_STRUCT* file = (FILE_STRUCT*) fileStruct;
partition = _FAT_partition_getPartitionFromPath (path);
if (partition == NULL) {
r->_errno = ENODEV;
return -1;
}
// Move the path pointer to the start of the actual path
if (strchr (path, ':') != NULL) {
path = strchr (path, ':') + 1;
}
if (strchr (path, ':') != NULL) {
r->_errno = EINVAL;
return -1;
}
// Determine which mode the file is openned for
if ((flags & 0x03) == O_RDONLY) {
// Open the file for read-only access
file->read = true;
file->write = false;
file->append = false;
} else if ((flags & 0x03) == O_WRONLY) {
// Open file for write only access
file->read = false;
file->write = true;
file->append = false;
} else if ((flags & 0x03) == O_RDWR) {
// Open file for read/write access
file->read = true;
file->write = true;
file->append = false;
} else {
r->_errno = EACCES;
return -1;
}
// Make sure we aren't trying to write to a read-only disc
if (file->write && partition->readOnly) {
r->_errno = EROFS;
return -1;
}
// Search for the file on the disc
fileExists = _FAT_directory_entryFromPath (partition, &dirEntry, path, NULL);
// The file shouldn't exist if we are trying to create it
if ((flags & O_CREAT) && (flags & O_EXCL) && fileExists) {
r->_errno = EEXIST;
return -1;
}
// It should not be a directory if we're openning a file,
if (fileExists && _FAT_directory_isDirectory(&dirEntry)) {
r->_errno = EISDIR;
return -1;
}
// If the file doesn't exist, create it if we're allowed to
if (!fileExists) {
if (flags & O_CREAT) {
if (partition->readOnly) {
// We can't write to a read-only partition
r->_errno = EROFS;
return -1;
}
// Create the file
// Get the directory it has to go in
pathEnd = strrchr (path, DIR_SEPARATOR);
if (pathEnd == NULL) {
// No path was specified
dirCluster = partition->cwdCluster;
pathEnd = path;
} else {
// Path was specified -- get the right dirCluster
// Recycling dirEntry, since it needs to be recreated anyway
if (!_FAT_directory_entryFromPath (partition, &dirEntry, path, pathEnd) ||
!_FAT_directory_isDirectory(&dirEntry)) {
r->_errno = ENOTDIR;
return -1;
}
dirCluster = _FAT_directory_entryGetCluster (dirEntry.entryData);
// Move the pathEnd past the last DIR_SEPARATOR
pathEnd += 1;
}
// Create the entry data
strncpy (dirEntry.filename, pathEnd, MAX_FILENAME_LENGTH - 1);
memset (dirEntry.entryData, 0, DIR_ENTRY_DATA_SIZE);
// Set the creation time and date
dirEntry.entryData[DIR_ENTRY_cTime_ms] = 0;
u16_to_u8array (dirEntry.entryData, DIR_ENTRY_cTime, _FAT_filetime_getTimeFromRTC());
u16_to_u8array (dirEntry.entryData, DIR_ENTRY_cDate, _FAT_filetime_getDateFromRTC());
if (!_FAT_directory_addEntry (partition, &dirEntry, dirCluster)) {
r->_errno = ENOSPC;
return -1;
}
} else {
// file doesn't exist, and we aren't creating it
r->_errno = ENOENT;
return -1;
}
}
file->filesize = u8array_to_u32 (dirEntry.entryData, DIR_ENTRY_fileSize);
/* Allow LARGEFILEs with undefined results
// Make sure that the file size can fit in the available space
if (!(flags & O_LARGEFILE) && (file->filesize >= (1<<31))) {
r->_errno = EFBIG;
return -1;
}
*/
// Make sure we aren't trying to write to a read-only file
if (file->write && !_FAT_directory_isWritable(&dirEntry)) {
r->_errno = EROFS;
return -1;
}
// Associate this file with a particular partition
file->partition = partition;
file->startCluster = _FAT_directory_entryGetCluster (dirEntry.entryData);
// Truncate the file if requested
if ((flags & O_TRUNC) && file->write && (file->startCluster != 0)) {
_FAT_fat_clearLinks (partition, file->startCluster);
file->startCluster = 0;
file->filesize = 0;
}
// Get a new cluster for the file if required
if (file->startCluster == 0) {
file->startCluster = _FAT_fat_linkFreeCluster (partition, CLUSTER_FREE);
}
// Remember the position of this file's directory entry
file->dirEntryStart = dirEntry.dataStart; // Points to the start of the LFN entries of a file, or the alias for no LFN
file->dirEntryEnd = dirEntry.dataEnd;
file->currentPosition = 0;
file->rwPosition.cluster = file->startCluster;
file->rwPosition.sector = 0;
file->rwPosition.byte = 0;
file->appendPosition.cluster = _FAT_fat_lastCluster (partition, file->startCluster);
file->appendPosition.sector = (file->filesize % partition->bytesPerCluster) / BYTES_PER_READ;
file->appendPosition.byte = file->filesize % BYTES_PER_READ;
// Check if the end of the file is on the end of a cluster
if ( (file->filesize > 0) && ((file->filesize % partition->bytesPerCluster)==0) ){
// Set flag to allocate a new cluster
file->appendPosition.sector = partition->sectorsPerCluster;
file->appendPosition.byte = 0;
}
if (flags & O_APPEND) {
file->append = true;
}
file->inUse = true;
partition->openFileCount += 1;
return (int) file;
}
int _FAT_close_r (struct _reent *r, int fd) {
FILE_STRUCT* file = (FILE_STRUCT*) fd;
u8 dirEntryData[DIR_ENTRY_DATA_SIZE];
if (!file->inUse) {
r->_errno = EBADF;
return -1;
}
if (file->write) {
// Load the old entry
_FAT_cache_readPartialSector (file->partition->cache, dirEntryData,
_FAT_fat_clusterToSector(file->partition, file->dirEntryEnd.cluster) + file->dirEntryEnd.sector,
file->dirEntryEnd.offset * DIR_ENTRY_DATA_SIZE, DIR_ENTRY_DATA_SIZE);
// Write new data to the directory entry
// File size
u32_to_u8array (dirEntryData, DIR_ENTRY_fileSize, file->filesize);
// Start cluster
u16_to_u8array (dirEntryData, DIR_ENTRY_cluster, file->startCluster);
u16_to_u8array (dirEntryData, DIR_ENTRY_clusterHigh, file->startCluster >> 16);
// Modification time and date
u16_to_u8array (dirEntryData, DIR_ENTRY_mTime, _FAT_filetime_getTimeFromRTC());
u16_to_u8array (dirEntryData, DIR_ENTRY_mDate, _FAT_filetime_getDateFromRTC());
// Access date
u16_to_u8array (dirEntryData, DIR_ENTRY_aDate, _FAT_filetime_getDateFromRTC());
// Write the new entry
_FAT_cache_writePartialSector (file->partition->cache, dirEntryData,
_FAT_fat_clusterToSector(file->partition, file->dirEntryEnd.cluster) + file->dirEntryEnd.sector,
file->dirEntryEnd.offset * DIR_ENTRY_DATA_SIZE, DIR_ENTRY_DATA_SIZE);
// Flush any sectors in the disc cache
if (!_FAT_cache_flush(file->partition->cache)) {
r->_errno = EIO;
return -1;
}
}
file->inUse = false;
file->partition->openFileCount -= 1;
return 0;
}
int _FAT_read_r (struct _reent *r, int fd, char *ptr, int len) {
FILE_STRUCT* file = (FILE_STRUCT*) fd;
PARTITION* partition;
CACHE* cache;
FILE_POSITION position;
u32 tempNextCluster;
int tempVar;
u32 remain;
bool flagNoError = true;
// Make sure we can actually read from the file
if ((file == NULL) || !file->inUse || !file->read) {
r->_errno = EBADF;
return 0;
}
// Don't try to read if the read pointer is past the end of file
if (file->currentPosition >= file->filesize) {
return 0;
}
// Don't read past end of file
if (len + file->currentPosition > file->filesize) {
r->_errno = EOVERFLOW;
len = file->filesize - file->currentPosition;
}
remain = len;
position = file->rwPosition;
partition = file->partition;
cache = file->partition->cache;
// Align to sector
tempVar = BYTES_PER_READ - position.byte;
if (tempVar > remain) {
tempVar = remain;
}
if ((tempVar < BYTES_PER_READ) && flagNoError)
{
_FAT_cache_readPartialSector ( cache, ptr, _FAT_fat_clusterToSector (partition, position.cluster) + position.sector,
position.byte, tempVar);
remain -= tempVar;
ptr += tempVar;
position.byte += tempVar;
if (position.byte >= BYTES_PER_READ) {
position.byte = 0;
position.sector++;
}
}
// align to cluster
// tempVar is number of sectors to read
if (remain > (partition->sectorsPerCluster - position.sector) * BYTES_PER_READ) {
tempVar = partition->sectorsPerCluster - position.sector;
} else {
tempVar = remain / BYTES_PER_READ;
}
if ((tempVar > 0) && flagNoError) {
_FAT_disc_readSectors (partition->disc, _FAT_fat_clusterToSector (partition, position.cluster) + position.sector,
tempVar, ptr);
ptr += tempVar * BYTES_PER_READ;
remain -= tempVar * BYTES_PER_READ;
position.sector += tempVar;
}
// Move onto next cluster
// It should get to here without reading anything if a cluster is due to be allocated
if (position.sector >= partition->sectorsPerCluster) {
tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster);
if ((remain == 0) && (tempNextCluster == CLUSTER_EOF)) {
position.sector = partition->sectorsPerCluster;
} else if (tempNextCluster == CLUSTER_FREE) {
r->_errno = EIO;
flagNoError = false;
} else {
position.sector = 0;
position.cluster = tempNextCluster;
}
}
// Read in whole clusters
while ((remain >= partition->bytesPerCluster) && flagNoError) {
_FAT_disc_readSectors (partition->disc, _FAT_fat_clusterToSector (partition, position.cluster), partition->sectorsPerCluster, ptr);
ptr += partition->bytesPerCluster;
remain -= partition->bytesPerCluster;
// Advance to next cluster
tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster);
if ((remain == 0) && (tempNextCluster == CLUSTER_EOF)) {
position.sector = partition->sectorsPerCluster;
} else if (tempNextCluster == CLUSTER_FREE) {
r->_errno = EIO;
flagNoError = false;
} else {
position.sector = 0;
position.cluster = tempNextCluster;
}
}
// Read remaining sectors
tempVar = remain / BYTES_PER_READ; // Number of sectors left
if ((tempVar > 0) && flagNoError) {
_FAT_disc_readSectors (partition->disc, _FAT_fat_clusterToSector (partition, position.cluster),
tempVar, ptr);
ptr += tempVar * BYTES_PER_READ;
remain -= tempVar * BYTES_PER_READ;
position.sector += tempVar;
}
// Last remaining sector
// Check if anything is left
if ((remain > 0) && flagNoError) {
_FAT_cache_readPartialSector ( cache, ptr,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, 0, remain);
position.byte += remain;
remain = 0;
}
// Length read is the wanted length minus the stuff not read
len = len - remain;
// Update file information
file->rwPosition = position;
file->currentPosition += len;
return len;
}
/*
Extend a file so that the size is the same as the rwPosition
*/
static bool file_extend_r (struct _reent *r, FILE_STRUCT* file) {
PARTITION* partition = file->partition;
CACHE* cache = file->partition->cache;
FILE_POSITION position;
u32 remain;
u8 zeroBuffer [BYTES_PER_READ] = {0};
u32 tempNextCluster;
position.byte = file->filesize % BYTES_PER_READ;
position.sector = (file->filesize % partition->bytesPerCluster) / BYTES_PER_READ;
position.cluster = _FAT_fat_lastCluster (partition, file->startCluster);
remain = file->currentPosition - file->filesize;
// Only need to clear to the end of the sector
if (remain + position.byte < BYTES_PER_READ) {
_FAT_cache_writePartialSector (cache, zeroBuffer,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, position.byte, remain);
position.byte += remain;
} else {
if (position.byte > 0) {
_FAT_cache_writePartialSector (cache, zeroBuffer,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, position.byte,
BYTES_PER_READ - position.byte);
remain -= (BYTES_PER_READ - position.byte);
position.byte = 0;
position.sector ++;
}
while (remain >= BYTES_PER_READ) {
if (position.sector >= partition->sectorsPerCluster) {
position.sector = 0;
tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster);
if ((tempNextCluster == CLUSTER_EOF) || (tempNextCluster == CLUSTER_FREE)) {
// Ran out of clusters so get a new one
tempNextCluster = _FAT_fat_linkFreeCluster(partition, position.cluster);
}
if (tempNextCluster == CLUSTER_FREE) {
// Couldn't get a cluster, so abort
r->_errno = ENOSPC;
return false;
} else {
position.cluster = tempNextCluster;
}
}
_FAT_disc_writeSectors (partition->disc,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, 1, zeroBuffer);
remain -= BYTES_PER_READ;
position.sector ++;
}
if (position.sector >= partition->sectorsPerCluster) {
position.sector = 0;
tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster);
if ((tempNextCluster == CLUSTER_EOF) || (tempNextCluster == CLUSTER_FREE)) {
// Ran out of clusters so get a new one
tempNextCluster = _FAT_fat_linkFreeCluster(partition, position.cluster);
}
if (tempNextCluster == CLUSTER_FREE) {
// Couldn't get a cluster, so abort
r->_errno = ENOSPC;
return false;
} else {
position.cluster = tempNextCluster;
}
}
if (remain > 0) {
_FAT_cache_writePartialSector (cache, zeroBuffer,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, 0, remain);
position.byte = remain;
}
}
file->rwPosition = position;
file->filesize = file->currentPosition;
return true;
}
int _FAT_write_r (struct _reent *r,int fd, const char *ptr, int len) {
FILE_STRUCT* file = (FILE_STRUCT*) fd;
PARTITION* partition;
CACHE* cache;
FILE_POSITION position;
u32 tempNextCluster;
int tempVar;
u32 remain;
bool flagNoError = true;
bool flagAppending = false;
// Make sure we can actually write to the file
if ((file == NULL) || !file->inUse || !file->write) {
r->_errno = EBADF;
return -1;
}
partition = file->partition;
cache = file->partition->cache;
remain = len;
if (file->append) {
position = file->appendPosition;
flagAppending = true;
} else {
// If the write pointer is past the end of the file, extend the file to that size
if (file->currentPosition > file->filesize) {
if (!file_extend_r (r, file)) {
return 0;
}
}
// Write at current read pointer
position = file->rwPosition;
// If it is writing past the current end of file, set appending flag
if (len + file->currentPosition > file->filesize) {
flagAppending = true;
}
}
// Move onto next cluster if needed
if (position.sector >= partition->sectorsPerCluster) {
position.sector = 0;
tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster);
if ((tempNextCluster == CLUSTER_EOF) || (tempNextCluster == CLUSTER_FREE)) {
// Ran out of clusters so get a new one
tempNextCluster = _FAT_fat_linkFreeCluster(partition, position.cluster);
}
if (tempNextCluster == CLUSTER_FREE) {
// Couldn't get a cluster, so abort
r->_errno = ENOSPC;
flagNoError = false;
} else {
position.cluster = tempNextCluster;
}
}
// Align to sector
tempVar = BYTES_PER_READ - position.byte;
if (tempVar > remain) {
tempVar = remain;
}
if ((tempVar < BYTES_PER_READ) && flagNoError) {
// Write partial sector to disk
_FAT_cache_writePartialSector (cache, ptr,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, position.byte, tempVar);
remain -= tempVar;
ptr += tempVar;
position.byte += tempVar;
// Move onto next sector
if (position.byte >= BYTES_PER_READ) {
position.byte = 0;
position.sector ++;
}
}
// Align to cluster
// tempVar is number of sectors to write
if (remain > (partition->sectorsPerCluster - position.sector) * BYTES_PER_READ) {
tempVar = partition->sectorsPerCluster - position.sector;
} else {
tempVar = remain / BYTES_PER_READ;
}
if ((tempVar > 0) && flagNoError) {
_FAT_disc_writeSectors (partition->disc,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, tempVar, ptr);
ptr += tempVar * BYTES_PER_READ;
remain -= tempVar * BYTES_PER_READ;
position.sector += tempVar;
}
if ((position.sector >= partition->sectorsPerCluster) && flagNoError && (remain > 0)) {
position.sector = 0;
tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster);
if ((tempNextCluster == CLUSTER_EOF) || (tempNextCluster == CLUSTER_FREE)) {
// Ran out of clusters so get a new one
tempNextCluster = _FAT_fat_linkFreeCluster(partition, position.cluster);
}
if (tempNextCluster == CLUSTER_FREE) {
// Couldn't get a cluster, so abort
r->_errno = ENOSPC;
flagNoError = false;
} else {
position.cluster = tempNextCluster;
}
}
// Write whole clusters
while ((remain >= partition->bytesPerCluster) && flagNoError) {
_FAT_disc_writeSectors (partition->disc, _FAT_fat_clusterToSector(partition, position.cluster),
partition->sectorsPerCluster, ptr);
ptr += partition->bytesPerCluster;
remain -= partition->bytesPerCluster;
if (remain > 0) {
tempNextCluster = _FAT_fat_nextCluster(partition, position.cluster);
if ((tempNextCluster == CLUSTER_EOF) || (tempNextCluster == CLUSTER_FREE)) {
// Ran out of clusters so get a new one
tempNextCluster = _FAT_fat_linkFreeCluster(partition, position.cluster);
}
if (tempNextCluster == CLUSTER_FREE) {
// Couldn't get a cluster, so abort
r->_errno = ENOSPC;
flagNoError = false;
} else {
position.cluster = tempNextCluster;
}
} else {
// Allocate a new cluster when next writing the file
position.sector = partition->sectorsPerCluster;
}
}
// Write remaining sectors
tempVar = remain / BYTES_PER_READ; // Number of sectors left
if ((tempVar > 0) && flagNoError) {
_FAT_disc_writeSectors (partition->disc, _FAT_fat_clusterToSector (partition, position.cluster),
tempVar, ptr);
ptr += tempVar * BYTES_PER_READ;
remain -= tempVar * BYTES_PER_READ;
position.sector += tempVar;
}
// Last remaining sector
if ((remain > 0) && flagNoError) {
if (flagAppending) {
_FAT_cache_eraseWritePartialSector ( cache, ptr,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, 0, remain);
} else {
_FAT_cache_writePartialSector ( cache, ptr,
_FAT_fat_clusterToSector (partition, position.cluster) + position.sector, 0, remain);
}
position.byte += remain;
remain = 0;
}
// Amount read is the originally requested amount minus stuff remaining
len = len - remain;
// Update file information
if (file->append) {
// Appending doesn't affect the read pointer
file->appendPosition = position;
file->filesize += len;
} else {
// Writing also shifts the read pointer
file->rwPosition = position;
file->currentPosition += len;
if (file->filesize < file->currentPosition) {
file->filesize = file->currentPosition;
}
}
return len;
}
int _FAT_seek_r (struct _reent *r, int fd, int pos, int dir) {
FILE_STRUCT* file = (FILE_STRUCT*) fd;
PARTITION* partition;
u32 cluster, nextCluster;
int clusCount;
int position;
if ((file == NULL) || (file->inUse == false)) {
// invalid file
r->_errno = EBADF;
return -1;
}
partition = file->partition;
switch (dir) {
case SEEK_SET:
position = pos;
break;
case SEEK_CUR:
position = file->currentPosition + pos;
break;
case SEEK_END:
position = file->filesize + pos;
break;
default:
r->_errno = EINVAL;
return -1;
}
if ((pos > 0) && (position < 0)) {
r->_errno = EOVERFLOW;
return -1;
}
if (position < 0) {
r->_errno = EINVAL;
return -1;
}
// Only change the read/write position if it is within the bounds of the current filesize
if (file->filesize > position) {
// Calculate the sector and byte of the current position,
// and store them
file->rwPosition.sector = (position % partition->bytesPerCluster) / BYTES_PER_READ;
file->rwPosition.byte = position % BYTES_PER_READ;
// Calculate where the correct cluster is
if (position >= file->currentPosition) {
clusCount = (position / partition->bytesPerCluster) - (file->currentPosition / partition->bytesPerCluster);
cluster = file->rwPosition.cluster;
} else {
clusCount = position / partition->bytesPerCluster;
cluster = file->startCluster;
}
nextCluster = _FAT_fat_nextCluster (partition, cluster);
while ((clusCount > 0) && (nextCluster != CLUSTER_FREE) && (nextCluster != CLUSTER_EOF)) {
clusCount--;
cluster = nextCluster;
nextCluster = _FAT_fat_nextCluster (partition, cluster);
}
// Check if ran out of clusters, and the file is being written to
if ((clusCount > 0) && (file->write || file->append)) {
// Set flag to allocate a new cluster
file->rwPosition.sector = partition->sectorsPerCluster;
file->rwPosition.byte = 0;
}
file->rwPosition.cluster = cluster;
}
// Save position
file->currentPosition = position;
return position;
}
int _FAT_fstat_r (struct _reent *r, int fd, struct stat *st) {
FILE_STRUCT* file = (FILE_STRUCT*) fd;
PARTITION* partition;
DIR_ENTRY fileEntry;
if ((file == NULL) || (file->inUse == false)) {
// invalid file
r->_errno = EBADF;
return -1;
}
partition = file->partition;
// Get the file's entry data
fileEntry.dataStart = file->dirEntryStart;
fileEntry.dataEnd = file->dirEntryEnd;
if (!_FAT_directory_entryFromPosition (partition, &fileEntry)) {
r->_errno = EIO;
return -1;
}
// Fill in the stat struct
_FAT_directory_entryStat (partition, &fileEntry, st);
// Fix stats that have changed since the file was openned
st->st_ino = (ino_t)(file->startCluster); // The file serial number is the start cluster
st->st_size = file->filesize; // File size
return 0;
}