/*
* fat.c
*
* Low-level operations on a volume with FAT filesystem
*
* Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia
* Author: Eugeny S. Mints <Eugeny.Mints@oktet.ru>
*
* @(#) $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <assert.h>
#include <rtems/libio_.h>
#include "fat.h"
#include "fat_fat_operations.h"
/* _fat_block_read --
* This function reads 'count' bytes from device filesystem is mounted on,
* starts at 'start+offset' position where 'start' computed in sectors
* and 'offset' is offset inside sector (reading may cross sectors
* boundary; in this case assumed we want to read sequential sector(s))
*
* PARAMETERS:
* mt_entry - mount table entry
* start - sector num to start read from
* offset - offset inside sector 'start'
* count - count of bytes to read
* buff - buffer provided by user
*
* RETURNS:
* bytes read on success, or -1 if error occured
* and errno set appropriately
*/
ssize_t
_fat_block_read(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t start,
uint32_t offset,
uint32_t count,
void *buff
)
{
int rc = RC_OK;
register fat_fs_info_t *fs_info = mt_entry->fs_info;
ssize_t cmpltd = 0;
uint32_t blk = start;
uint32_t ofs = offset;
bdbuf_buffer *block = NULL;
uint32_t c = 0;
while (count > 0)
{
rc = fat_buf_access(fs_info, blk, FAT_OP_TYPE_READ, &block);
if (rc != RC_OK)
return -1;
c = MIN(count, (fs_info->vol.bps - ofs));
memcpy((buff + cmpltd), (block->buffer + ofs), c);
count -= c;
cmpltd += c;
blk++;
ofs = 0;
}
return cmpltd;
}
/* _fat_block_write --
* This function write 'count' bytes to device filesystem is mounted on,
* starts at 'start+offset' position where 'start' computed in sectors
* and 'offset' is offset inside sector (writing may cross sectors
* boundary; in this case assumed we want to write sequential sector(s))
*
* PARAMETERS:
* mt_entry - mount table entry
* start - sector num to start read from
* offset - offset inside sector 'start'
* count - count of bytes to write
* buff - buffer provided by user
*
* RETURNS:
* bytes written on success, or -1 if error occured
* and errno set appropriately
*/
ssize_t
_fat_block_write(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t start,
uint32_t offset,
uint32_t count,
const void *buff)
{
int rc = RC_OK;
fat_fs_info_t *fs_info = mt_entry->fs_info;
ssize_t cmpltd = 0;
uint32_t blk = start;
uint32_t ofs = offset;
bdbuf_buffer *block = NULL;
uint32_t c = 0;
while(count > 0)
{
c = MIN(count, (fs_info->vol.bps - ofs));
if (c == fs_info->vol.bps)
rc = fat_buf_access(fs_info, blk, FAT_OP_TYPE_GET, &block);
else
rc = fat_buf_access(fs_info, blk, FAT_OP_TYPE_READ, &block);
if (rc != RC_OK)
return -1;
memcpy((block->buffer + ofs), (buff + cmpltd), c);
fat_buf_mark_modified(fs_info);
count -= c;
cmpltd +=c;
blk++;
ofs = 0;
}
return cmpltd;
}
/* fat_cluster_read --
* wrapper for reading a whole cluster at once
*
* PARAMETERS:
* mt_entry - mount table entry
* cln - number of cluster to read
* buff - buffer provided by user
*
* RETURNS:
* bytes read on success, or -1 if error occured
* and errno set appropriately
*/
ssize_t
fat_cluster_read(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t cln,
void *buff
)
{
fat_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t fsec = 0;
fsec = fat_cluster_num_to_sector_num(mt_entry, cln);
return _fat_block_read(mt_entry, fsec, 0,
fs_info->vol.spc << fs_info->vol.sec_log2, buff);
}
/* fat_cluster_write --
* wrapper for writting a whole cluster at once
*
* PARAMETERS:
* mt_entry - mount table entry
* cln - number of cluster to write
* buff - buffer provided by user
*
* RETURNS:
* bytes written on success, or -1 if error occured
* and errno set appropriately
*/
ssize_t
fat_cluster_write(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t cln,
const void *buff
)
{
fat_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t fsec = 0;
fsec = fat_cluster_num_to_sector_num(mt_entry, cln);
return _fat_block_write(mt_entry, fsec, 0,
fs_info->vol.spc << fs_info->vol.sec_log2, buff);
}
/* fat_init_volume_info --
* Get inforamtion about volume on which filesystem is mounted on
*
* PARAMETERS:
* mt_entry - mount table entry
*
* RETURNS:
* RC_OK on success, or -1 if error occured
* and errno set appropriately
*/
int
fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry)
{
int rc = RC_OK;
fat_fs_info_t *fs_info = mt_entry->fs_info;
register fat_vol_t *vol = &fs_info->vol;
uint32_t data_secs = 0;
char boot_rec[FAT_MAX_BPB_SIZE];
char fs_info_sector[FAT_USEFUL_INFO_SIZE];
ssize_t ret = 0;
int fd;
struct stat stat_buf;
int i = 0;
rc = stat(mt_entry->dev, &stat_buf);
if (rc == -1)
return rc;
/* rtmes feature: no block devices, all are character devices */
if (!S_ISCHR(stat_buf.st_mode))
set_errno_and_return_minus_one(ENOTBLK);
/* check that device is registred as block device and lock it */
vol->dd = rtems_disk_lookup(stat_buf.st_dev);
if (vol->dd == NULL)
set_errno_and_return_minus_one(ENOTBLK);
vol->dev = stat_buf.st_dev;
fd = open(mt_entry->dev, O_RDONLY);
if (fd == -1)
{
rtems_disk_release(vol->dd);
return -1;
}
ret = read(fd, (void *)boot_rec, FAT_MAX_BPB_SIZE);
if ( ret != FAT_MAX_BPB_SIZE )
{
close(fd);
rtems_disk_release(vol->dd);
set_errno_and_return_minus_one( EIO );
}
close(fd);
vol->bps = FAT_BR_BYTES_PER_SECTOR(boot_rec);
if ( (vol->bps != 512) &&
(vol->bps != 1024) &&
(vol->bps != 2048) &&
(vol->bps != 4096))
{
rtems_disk_release(vol->dd);
set_errno_and_return_minus_one( EINVAL );
}
for (vol->sec_mul = 0, i = (vol->bps >> FAT_SECTOR512_BITS); (i & 1) == 0;
i >>= 1, vol->sec_mul++);
for (vol->sec_log2 = 0, i = vol->bps; (i & 1) == 0;
i >>= 1, vol->sec_log2++);
vol->spc = FAT_BR_SECTORS_PER_CLUSTER(boot_rec);
/*
* "sectors per cluster" of zero is invalid
* (and would hang the following loop)
*/
if (vol->spc == 0)
{
rtems_disk_release(vol->dd);
set_errno_and_return_minus_one(EINVAL);
}
for (vol->spc_log2 = 0, i = vol->spc; (i & 1) == 0;
i >>= 1, vol->spc_log2++);
/*
* "bytes per cluster" value greater than 32K is invalid
*/
if ((vol->bpc = vol->bps << vol->spc_log2) > MS_BYTES_PER_CLUSTER_LIMIT)
{
rtems_disk_release(vol->dd);
set_errno_and_return_minus_one(EINVAL);
}
for (vol->bpc_log2 = 0, i = vol->bpc; (i & 1) == 0;
i >>= 1, vol->bpc_log2++);
vol->fats = FAT_BR_FAT_NUM(boot_rec);
vol->fat_loc = FAT_BR_RESERVED_SECTORS_NUM(boot_rec);
vol->rdir_entrs = FAT_BR_FILES_PER_ROOT_DIR(boot_rec);
/* calculate the count of sectors occupied by the root directory */
vol->rdir_secs = ((vol->rdir_entrs * FAT_DIRENTRY_SIZE) + (vol->bps - 1)) /
vol->bps;
vol->rdir_size = vol->rdir_secs << vol->sec_log2;
if ( (FAT_BR_SECTORS_PER_FAT(boot_rec)) != 0)
vol->fat_length = FAT_BR_SECTORS_PER_FAT(boot_rec);
else
vol->fat_length = FAT_BR_SECTORS_PER_FAT32(boot_rec);
vol->data_fsec = vol->fat_loc + vol->fats * vol->fat_length +
vol->rdir_secs;
/* for FAT12/16 root dir starts at(sector) */
vol->rdir_loc = vol->fat_loc + vol->fats * vol->fat_length;
if ( (FAT_BR_TOTAL_SECTORS_NUM16(boot_rec)) != 0)
vol->tot_secs = FAT_BR_TOTAL_SECTORS_NUM16(boot_rec);
else
vol->tot_secs = FAT_BR_TOTAL_SECTORS_NUM32(boot_rec);
data_secs = vol->tot_secs - vol->data_fsec;
vol->data_cls = data_secs / vol->spc;
/* determine FAT type at least */
if ( vol->data_cls < FAT_FAT12_MAX_CLN)
{
vol->type = FAT_FAT12;
vol->mask = FAT_FAT12_MASK;
vol->eoc_val = FAT_FAT12_EOC;
}
else
{
if ( vol->data_cls < FAT_FAT16_MAX_CLN)
{
vol->type = FAT_FAT16;
vol->mask = FAT_FAT16_MASK;
vol->eoc_val = FAT_FAT16_EOC;
}
else
{
vol->type = FAT_FAT32;
vol->mask = FAT_FAT32_MASK;
vol->eoc_val = FAT_FAT32_EOC;
}
}
if (vol->type == FAT_FAT32)
{
vol->rdir_cl = FAT_BR_FAT32_ROOT_CLUSTER(boot_rec);
vol->mirror = FAT_BR_EXT_FLAGS(boot_rec) & FAT_BR_EXT_FLAGS_MIRROR;
if (vol->mirror)
vol->afat = FAT_BR_EXT_FLAGS(boot_rec) & FAT_BR_EXT_FLAGS_FAT_NUM;
else
vol->afat = 0;
vol->info_sec = FAT_BR_FAT32_FS_INFO_SECTOR(boot_rec);
if( vol->info_sec == 0 )
{
rtems_disk_release(vol->dd);
set_errno_and_return_minus_one( EINVAL );
}
else
{
ret = _fat_block_read(mt_entry, vol->info_sec , 0,
FAT_FSI_LEADSIG_SIZE, fs_info_sector);
if ( ret < 0 )
{
rtems_disk_release(vol->dd);
return -1;
}
if (FAT_FSINFO_LEAD_SIGNATURE(fs_info_sector) !=
FAT_FSINFO_LEAD_SIGNATURE_VALUE)
{
rtems_disk_release(vol->dd);
set_errno_and_return_minus_one( EINVAL );
}
else
{
ret = _fat_block_read(mt_entry, vol->info_sec , FAT_FSI_INFO,
FAT_USEFUL_INFO_SIZE, fs_info_sector);
if ( ret < 0 )
{
rtems_disk_release(vol->dd);
return -1;
}
vol->free_cls = FAT_FSINFO_FREE_CLUSTER_COUNT(fs_info_sector);
vol->next_cl = FAT_FSINFO_NEXT_FREE_CLUSTER(fs_info_sector);
rc = fat_fat32_update_fsinfo_sector(mt_entry, 0xFFFFFFFF,
0xFFFFFFFF);
if ( rc != RC_OK )
{
rtems_disk_release(vol->dd);
return rc;
}
}
}
}
else
{
vol->rdir_cl = 0;
vol->mirror = 0;
vol->afat = 0;
vol->free_cls = 0xFFFFFFFF;
vol->next_cl = 0xFFFFFFFF;
}
vol->afat_loc = vol->fat_loc + vol->fat_length * vol->afat;
/* set up collection of fat-files fd */
fs_info->vhash = calloc(FAT_HASH_SIZE, sizeof(Chain_Control));
if ( fs_info->vhash == NULL )
{
rtems_disk_release(vol->dd);
set_errno_and_return_minus_one( ENOMEM );
}
for (i = 0; i < FAT_HASH_SIZE; i++)
_Chain_Initialize_empty(fs_info->vhash + i);
fs_info->rhash = calloc(FAT_HASH_SIZE, sizeof(Chain_Control));
if ( fs_info->rhash == NULL )
{
rtems_disk_release(vol->dd);
free(fs_info->vhash);
set_errno_and_return_minus_one( ENOMEM );
}
for (i = 0; i < FAT_HASH_SIZE; i++)
_Chain_Initialize_empty(fs_info->rhash + i);
fs_info->uino_pool_size = FAT_UINO_POOL_INIT_SIZE;
fs_info->uino_base = (vol->tot_secs << vol->sec_mul) << 4;
fs_info->index = 0;
fs_info->uino = (char *)calloc(fs_info->uino_pool_size, sizeof(char));
if ( fs_info->uino == NULL )
{
rtems_disk_release(vol->dd);
free(fs_info->vhash);
free(fs_info->rhash);
set_errno_and_return_minus_one( ENOMEM );
}
fs_info->sec_buf = (char *)calloc(vol->bps, sizeof(char));
if (fs_info->sec_buf == NULL)
{
rtems_disk_release(vol->dd);
free(fs_info->vhash);
free(fs_info->rhash);
free(fs_info->uino);
set_errno_and_return_minus_one( ENOMEM );
}
return RC_OK;
}
/* fat_shutdown_drive --
* Free all allocated resources and synchronize all necessary data
*
* PARAMETERS:
* mt_entry - mount table entry
*
* RETURNS:
* RC_OK on success, or -1 if error occured
* and errno set appropriately
*/
int
fat_shutdown_drive(rtems_filesystem_mount_table_entry_t *mt_entry)
{
int rc = RC_OK;
fat_fs_info_t *fs_info = mt_entry->fs_info;
int i = 0;
if (fs_info->vol.type & FAT_FAT32)
{
rc = fat_fat32_update_fsinfo_sector(mt_entry, fs_info->vol.free_cls,
fs_info->vol.next_cl);
if ( rc != RC_OK )
rc = -1;
}
fat_buf_release(fs_info);
if (rtems_bdbuf_syncdev(fs_info->vol.dev) != RTEMS_SUCCESSFUL)
rc = -1;
for (i = 0; i < FAT_HASH_SIZE; i++)
{
Chain_Node *node = NULL;
Chain_Control *the_chain = fs_info->vhash + i;
while ( (node = _Chain_Get(the_chain)) != NULL )
free(node);
}
for (i = 0; i < FAT_HASH_SIZE; i++)
{
Chain_Node *node = NULL;
Chain_Control *the_chain = fs_info->rhash + i;
while ( (node = _Chain_Get(the_chain)) != NULL )
free(node);
}
free(fs_info->vhash);
free(fs_info->rhash);
free(fs_info->uino);
free(fs_info->sec_buf);
rtems_disk_release(fs_info->vol.dd);
if (rc)
errno = EIO;
return rc;
}
/* fat_init_clusters_chain --
* Zeroing contents of all clusters in the chain
*
* PARAMETERS:
* mt_entry - mount table entry
* start_cluster_num - num of first cluster in the chain
*
* RETURNS:
* RC_OK on success, or -1 if error occured
* and errno set appropriately
*/
int
fat_init_clusters_chain(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t start_cln
)
{
int rc = RC_OK;
ssize_t ret = 0;
register fat_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t cur_cln = start_cln;
char *buf;
buf = calloc(fs_info->vol.bpc, sizeof(char));
if ( buf == NULL )
set_errno_and_return_minus_one( EIO );
while ((cur_cln & fs_info->vol.mask) < fs_info->vol.eoc_val)
{
ret = fat_cluster_write(mt_entry, cur_cln, buf);
if ( ret == -1 )
{
free(buf);
return -1;
}
rc = fat_get_fat_cluster(mt_entry, cur_cln, &cur_cln);
if ( rc != RC_OK )
{
free(buf);
return rc;
}
}
free(buf);
return rc;
}
#define FAT_UNIQ_INO_BASE 0x0FFFFF00
#define FAT_UNIQ_INO_IS_BUSY(index, arr) \
(((arr)[((index)>>3)]>>((index) & (8-1))) & 0x01)
#define FAT_SET_UNIQ_INO_BUSY(index, arr) \
((arr)[((index)>>3)] |= (0x01<<((index) & (8-1))))
#define FAT_SET_UNIQ_INO_FREE(index, arr) \
((arr)[((index)>>3)] &= (~(0x01<<((index) & (8-1)))))
/* fat_get_unique_ino --
* Allocate unique ino from unique ino pool
*
* PARAMETERS:
* mt_entry - mount table entry
*
* RETURNS:
* unique inode number on success, or 0 if there is no free unique inode
* number in the pool
*
* ATTENTION:
* 0 means FAILED !!!
*
*/
uint32_t
fat_get_unique_ino(rtems_filesystem_mount_table_entry_t *mt_entry)
{
register fat_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t j = 0;
rtems_boolean resrc_unsuff = FALSE;
while (!resrc_unsuff)
{
for (j = 0; j < fs_info->uino_pool_size; j++)
{
if (!FAT_UNIQ_INO_IS_BUSY(fs_info->index, fs_info->uino))
{
FAT_SET_UNIQ_INO_BUSY(fs_info->index, fs_info->uino);
return (fs_info->uino_base + fs_info->index);
}
fs_info->index++;
if (fs_info->index >= fs_info->uino_pool_size)
fs_info->index = 0;
}
if ((fs_info->uino_pool_size << 1) < (0x0FFFFFFF - fs_info->uino_base))
{
fs_info->uino_pool_size <<= 1;
fs_info->uino = realloc(fs_info->uino, fs_info->uino_pool_size);
if (fs_info->uino != NULL)
fs_info->index = fs_info->uino_pool_size;
else
resrc_unsuff = TRUE;
}
else
resrc_unsuff = TRUE;
}
return 0;
}
/* fat_free_unique_ino --
* Return unique ino to unique ino pool
*
* PARAMETERS:
* mt_entry - mount table entry
* ino - inode number to free
*
* RETURNS:
* None
*/
void
fat_free_unique_ino(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t ino
)
{
fat_fs_info_t *fs_info = mt_entry->fs_info;
FAT_SET_UNIQ_INO_FREE((ino - fs_info->uino_base), fs_info->uino);
}
/* fat_ino_is_unique --
* Test whether ino is from unique ino pool
*
* PARAMETERS:
* mt_entry - mount table entry
* ino - ino to be tested
*
* RETURNS:
* TRUE if ino is allocated from unique ino pool, FALSE otherwise
*/
inline rtems_boolean
fat_ino_is_unique(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t ino
)
{
fat_fs_info_t *fs_info = mt_entry->fs_info;
return (ino >= fs_info->uino_base);
}
/* fat_fat32_update_fsinfo_sector --
* Synchronize fsinfo sector for FAT32 volumes
*
* PARAMETERS:
* mt_entry - mount table entry
* free_count - count of free clusters
* next_free - the next free cluster num
*
* RETURNS:
* RC_OK on success, or -1 if error occured (errno set appropriately)
*/
int
fat_fat32_update_fsinfo_sector(
rtems_filesystem_mount_table_entry_t *mt_entry,
uint32_t free_count,
uint32_t next_free
)
{
ssize_t ret1 = 0, ret2 = 0;
register fat_fs_info_t *fs_info = mt_entry->fs_info;
uint32_t le_free_count = 0;
uint32_t le_next_free = 0;
le_free_count = CT_LE_L(free_count);
le_next_free = CT_LE_L(next_free);
ret1 = _fat_block_write(mt_entry,
fs_info->vol.info_sec,
FAT_FSINFO_FREE_CLUSTER_COUNT_OFFSET,
4,
(char *)(&le_free_count));
ret2 = _fat_block_write(mt_entry,
fs_info->vol.info_sec,
FAT_FSINFO_NEXT_FREE_CLUSTER_OFFSET,
4,
(char *)(&le_next_free));
if ( (ret1 < 0) || (ret2 < 0) )
return -1;
return RC_OK;
}
