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/*
* fat.h
*
* Constants/data structures/prototypes for 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>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* @(#) $Id$
*/
#ifndef __DOSFS_FAT_H__
#define __DOSFS_FAT_H__
#ifdef __cplusplus
extern "C" {
#endif
#include <rtems/seterr.h>
/* XXX: temporary hack :(( */
#ifndef set_errno_and_return_minus_one
#define set_errno_and_return_minus_one rtems_set_errno_and_return_minus_one
#endif /* set_errno_and_return_minus_one */
#include <rtems/score/cpu.h>
#include <errno.h>
#include <rtems/bdbuf.h>
#define DBG1(x) x
#define DBG2(x) x
#ifndef RC_OK
#define RC_OK 0x00000000
#endif
/*
* Remember that all FAT file system on disk data structure is
* "little endian"!
* (derived from linux)
*/
/*
* Conversion from and to little-endian byte order. (no-op on i386/i486)
*
* Naming: Ca_b_c, where a: F = from, T = to, b: LE = little-endian,
* BE = big-endian, c: W = word (16 bits), L = longword (32 bits)
*/
#if (CPU_BIG_ENDIAN == TRUE)
# define CF_LE_W(v) CPU_swap_u16(v)
# define CF_LE_L(v) CPU_swap_u32(v)
# define CT_LE_W(v) CPU_swap_u16(v)
# define CT_LE_L(v) CPU_swap_u32(v)
#else
# define CF_LE_W(v) (v)
# define CF_LE_L(v) (v)
# define CT_LE_W(v) (v)
# define CT_LE_L(v) (v)
#endif
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define FAT_HASH_SIZE 2
#define FAT_HASH_MODULE FAT_HASH_SIZE
#define FAT_SECTOR512_SIZE 512 /* sector size (bytes) */
#define FAT_SECTOR512_BITS 9 /* log2(SECTOR_SIZE) */
/* maximum + 1 number of clusters for FAT12 */
#define FAT_FAT12_MAX_CLN 4085
/* maximum + 1 number of clusters for FAT16 */
#define FAT_FAT16_MAX_CLN 65525
#define FAT_FAT12 0x01
#define FAT_FAT16 0x02
#define FAT_FAT32 0x04
#define FAT_UNDEFINED_VALUE 0xFFFFFFFF
#define FAT_FAT12_EOC 0x0FFF
#define FAT_FAT16_EOC 0xFFFF
#define FAT_FAT32_EOC 0x0FFFFFFF
#define FAT_FAT12_FREE 0x0000
#define FAT_FAT16_FREE 0x0000
#define FAT_FAT32_FREE 0x00000000
#define FAT_GENFAT_EOC 0xFFFFFFFF
#define FAT_GENFAT_FREE 0x00000000
#define FAT_FAT12_SHIFT 0x04
#define FAT_FAT12_MASK 0x00000FFF
#define FAT_FAT16_MASK 0x0000FFFF
#define FAT_FAT32_MASK 0x0FFFFFFF
#define FAT_MAX_BPB_SIZE 90
/* size of useful information in FSInfo sector */
#define FAT_USEFUL_INFO_SIZE 12
#define FAT_VAL8(x, ofs) (unsigned8)(*((unsigned8 *)(x) + (ofs)))
#define FAT_VAL16(x, ofs) \
(unsigned16)( (*((unsigned8 *)(x) + (ofs))) | \
((*((unsigned8 *)(x) + (ofs) + 1)) << 8) )
#define FAT_VAL32(x, ofs) \
(unsigned32)( (*((unsigned8 *)(x) + (ofs))) | \
((*((unsigned8 *)(x) + (ofs) + 1)) << 8) | \
((*((unsigned8 *)(x) + (ofs) + 2)) << 16) | \
((*((unsigned8 *)(x) + (ofs) + 3)) << 24) )
/* macros to access boot sector fields */
#define FAT_BR_BYTES_PER_SECTOR(x) FAT_VAL16(x, 11)
#define FAT_BR_SECTORS_PER_CLUSTER(x) FAT_VAL8(x, 13)
#define FAT_BR_RESERVED_SECTORS_NUM(x) FAT_VAL16(x, 14)
#define FAT_BR_FAT_NUM(x) FAT_VAL8(x, 16)
#define FAT_BR_FILES_PER_ROOT_DIR(x) FAT_VAL16(x, 17)
#define FAT_BR_TOTAL_SECTORS_NUM16(x) FAT_VAL16(x, 19)
#define FAT_BR_MEDIA(x) FAT_VAL8(x, 21)
#define FAT_BR_SECTORS_PER_FAT(x) FAT_VAL16(x, 22)
#define FAT_BR_TOTAL_SECTORS_NUM32(x) FAT_VAL32(x, 32)
#define FAT_BR_SECTORS_PER_FAT32(x) FAT_VAL32(x, 36)
#define FAT_BR_EXT_FLAGS(x) FAT_VAL16(x, 40)
#define FAT_BR_FAT32_ROOT_CLUSTER(x) FAT_VAL32(x, 44)
#define FAT_BR_FAT32_FS_INFO_SECTOR(x) FAT_VAL16(x, 48)
#define FAT_FSINFO_LEAD_SIGNATURE(x) FAT_VAL32(x, 0)
/*
* I read FSInfo sector from offset 484 to access the information, so offsets
* of these fields a relative
*/
#define FAT_FSINFO_FREE_CLUSTER_COUNT(x) FAT_VAL32(x, 4)
#define FAT_FSINFO_NEXT_FREE_CLUSTER(x) FAT_VAL32(x, 8)
#define FAT_FSINFO_FREE_CLUSTER_COUNT_OFFSET 488
#define FAT_FSINFO_NEXT_FREE_CLUSTER_OFFSET 492
#define FAT_RSRVD_CLN 0x02
#define FAT_FSINFO_LEAD_SIGNATURE_VALUE 0x41615252
#define FAT_FSI_LEADSIG_SIZE 0x04
#define FAT_FSI_INFO 484
#define MS_BYTES_PER_CLUSTER_LIMIT 0x8000 /* 32K */
#define FAT_BR_EXT_FLAGS_MIRROR 0x0080
#define FAT_BR_EXT_FLAGS_FAT_NUM 0x000F
#define FAT_DIRENTRY_SIZE 32
#define FAT_DIRENTRIES_PER_SEC512 16
/*
* Volume descriptor
* Description of the volume the FAT filesystem is located on - generally
* the fields of the structure corresponde to Boot Sector and BPB Srtucture
* (see M$ White Paper) fields
*/
typedef struct fat_vol_s
{
unsigned16 bps; /* bytes per sector */
unsigned8 sec_log2; /* log2 of bps */
unsigned8 sec_mul; /* log2 of 512bts sectors number per sector */
unsigned8 spc; /* sectors per cluster */
unsigned8 spc_log2; /* log2 of spc */
unsigned16 bpc; /* bytes per cluster */
unsigned8 bpc_log2; /* log2 of bytes per cluster */
unsigned8 fats; /* number of FATs */
unsigned8 type; /* FAT type */
unsigned32 mask;
unsigned32 eoc_val;
unsigned16 fat_loc; /* FAT start */
unsigned32 fat_length; /* sectors per FAT */
unsigned32 rdir_loc; /* root directory start */
unsigned16 rdir_entrs; /* files per root directory */
unsigned32 rdir_secs; /* sectors per root directory */
unsigned32 rdir_size; /* root directory size in bytes */
unsigned32 tot_secs; /* total count of sectors */
unsigned32 data_fsec; /* first data sector */
unsigned32 data_cls; /* count of data clusters */
unsigned32 rdir_cl; /* first cluster of the root directory */
unsigned16 info_sec; /* FSInfo Sector Structure location */
unsigned32 free_cls; /* last known free clusters count */
unsigned32 next_cl; /* next free cluster number */
unsigned8 mirror; /* mirroring enabla/disable */
unsigned32 afat_loc; /* active FAT location */
unsigned8 afat; /* the number of active FAT */
dev_t dev; /* device ID */
disk_device *dd; /* disk device (see libblock) */
void *private_data; /* reserved */
} fat_vol_t;
typedef struct fat_cache_s
{
unsigned32 blk_num;
rtems_boolean modified;
unsigned8 state;
bdbuf_buffer *buf;
} fat_cache_t;
/*
* This structure identifies the instance of the filesystem on the FAT
* ("fat-file") level.
*/
typedef struct fat_fs_info_s
{
fat_vol_t vol; /* volume descriptor */
Chain_Control *vhash; /* "vhash" of fat-file descriptors */
Chain_Control *rhash; /* "rhash" of fat-file descriptors */
char *uino; /* array of unique ino numbers */
unsigned32 index;
unsigned32 uino_pool_size; /* size */
unsigned32 uino_base;
fat_cache_t c; /* cache */
unsigned8 *sec_buf; /* just placeholder for anything */
} fat_fs_info_t;
/*
* if the name we looking for is file we store not only first data cluster
* number, but and cluster number and offset for directory entry for this
* name
*/
typedef struct fat_auxiliary_s
{
unsigned32 cln;
unsigned32 ofs;
} fat_auxiliary_t;
#define FAT_FAT_OFFSET(fat_type, cln) \
((fat_type) & FAT_FAT12 ? ((cln) + ((cln) >> 1)) : \
(fat_type) & FAT_FAT16 ? ((cln) << 1) : \
((cln) << 2))
#define FAT_CLUSTER_IS_ODD(n) ((n) & 0x0001)
#define FAT12_SHIFT 0x4 /* half of a byte */
/* initial size of array of unique ino */
#define FAT_UINO_POOL_INIT_SIZE 0x100
/* cache support */
#define FAT_CACHE_EMPTY 0x0
#define FAT_CACHE_ACTUAL 0x1
#define FAT_OP_TYPE_READ 0x1
#define FAT_OP_TYPE_GET 0x2
static inline unsigned32
fat_cluster_num_to_sector_num(
rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 cln
)
{
register fat_fs_info_t *fs_info = mt_entry->fs_info;
if ( (cln == 0) && (fs_info->vol.type & (FAT_FAT12 | FAT_FAT16)) )
return fs_info->vol.rdir_loc;
return (((cln - FAT_RSRVD_CLN) << fs_info->vol.spc_log2) +
fs_info->vol.data_fsec);
}
static inline unsigned32
fat_cluster_num_to_sector512_num(
rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 cln
)
{
fat_fs_info_t *fs_info = mt_entry->fs_info;
if (cln == 1)
return 1;
return (fat_cluster_num_to_sector_num(mt_entry, cln) <<
fs_info->vol.sec_mul);
}
static inline int
fat_buf_access(fat_fs_info_t *fs_info, unsigned32 blk, int op_type,
bdbuf_buffer **buf)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
unsigned8 i;
rtems_boolean sec_of_fat;
if (fs_info->c.state == FAT_CACHE_EMPTY)
{
if (op_type == FAT_OP_TYPE_READ)
sc = rtems_bdbuf_read(fs_info->vol.dev, blk, &fs_info->c.buf);
else
sc = rtems_bdbuf_get(fs_info->vol.dev, blk, &fs_info->c.buf);
if (sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(EIO);
fs_info->c.blk_num = blk;
fs_info->c.state = FAT_CACHE_ACTUAL;
}
sec_of_fat = ((fs_info->c.blk_num >= fs_info->vol.fat_loc) &&
(fs_info->c.blk_num < fs_info->vol.rdir_loc));
if (fs_info->c.blk_num != blk)
{
if (fs_info->c.modified)
{
if (sec_of_fat && !fs_info->vol.mirror)
memcpy(fs_info->sec_buf, fs_info->c.buf->buffer,
fs_info->vol.bps);
sc = rtems_bdbuf_release_modified(fs_info->c.buf);
if (sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(EIO);
fs_info->c.modified = 0;
if (sec_of_fat && !fs_info->vol.mirror)
{
bdbuf_buffer *b;
for (i = 1; i < fs_info->vol.fats; i++)
{
sc = rtems_bdbuf_get(fs_info->vol.dev,
fs_info->c.blk_num +
fs_info->vol.fat_length * i,
&b);
if ( sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(ENOMEM);
memcpy(b->buffer, fs_info->sec_buf, fs_info->vol.bps);
sc = rtems_bdbuf_release_modified(b);
if ( sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(ENOMEM);
}
}
}
else
{
sc = rtems_bdbuf_release(fs_info->c.buf);
if (sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(EIO);
}
if (op_type == FAT_OP_TYPE_READ)
sc = rtems_bdbuf_read(fs_info->vol.dev, blk, &fs_info->c.buf);
else
sc = rtems_bdbuf_get(fs_info->vol.dev, blk, &fs_info->c.buf);
if (sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(EIO);
fs_info->c.blk_num = blk;
}
*buf = fs_info->c.buf;
return RC_OK;
}
static inline int
fat_buf_release(fat_fs_info_t *fs_info)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
unsigned8 i;
rtems_boolean sec_of_fat;
if (fs_info->c.state == FAT_CACHE_EMPTY)
return RC_OK;
sec_of_fat = ((fs_info->c.blk_num >= fs_info->vol.fat_loc) &&
(fs_info->c.blk_num < fs_info->vol.rdir_loc));
if (fs_info->c.modified)
{
if (sec_of_fat && !fs_info->vol.mirror)
memcpy(fs_info->sec_buf, fs_info->c.buf->buffer, fs_info->vol.bps);
sc = rtems_bdbuf_release_modified(fs_info->c.buf);
if (sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(EIO);
fs_info->c.modified = 0;
if (sec_of_fat && !fs_info->vol.mirror)
{
bdbuf_buffer *b;
for (i = 1; i < fs_info->vol.fats; i++)
{
sc = rtems_bdbuf_get(fs_info->vol.dev,
fs_info->c.blk_num +
fs_info->vol.fat_length * i,
&b);
if ( sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(ENOMEM);
memcpy(b->buffer, fs_info->sec_buf, fs_info->vol.bps);
sc = rtems_bdbuf_release_modified(b);
if ( sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(ENOMEM);
}
}
}
else
{
sc = rtems_bdbuf_release(fs_info->c.buf);
if (sc != RTEMS_SUCCESSFUL)
set_errno_and_return_minus_one(EIO);
}
fs_info->c.state = FAT_CACHE_EMPTY;
return RC_OK;
}
static inline void
fat_buf_mark_modified(fat_fs_info_t *fs_info)
{
fs_info->c.modified = TRUE;
}
ssize_t
_fat_block_read(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 start,
unsigned32 offset,
unsigned32 count,
void *buff);
ssize_t
_fat_block_write(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 start,
unsigned32 offset,
unsigned32 count,
const void *buff);
ssize_t
fat_cluster_read(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 cln,
void *buff);
ssize_t
fat_cluster_write(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 cln,
const void *buff);
int
fat_init_volume_info(rtems_filesystem_mount_table_entry_t *mt_entry);
int
fat_init_clusters_chain(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 start_cln);
unsigned32
fat_cluster_num_to_sector_num(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 cln);
int
fat_shutdown_drive(rtems_filesystem_mount_table_entry_t *mt_entry);
unsigned32
fat_get_unique_ino(rtems_filesystem_mount_table_entry_t *mt_entry);
rtems_boolean
fat_ino_is_unique(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 ino);
void
fat_free_unique_ino(rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 ino);
int
fat_fat32_update_fsinfo_sector(
rtems_filesystem_mount_table_entry_t *mt_entry,
unsigned32 free_count,
unsigned32 next_free
);
#ifdef __cplusplus
}
#endif
#endif /* __DOSFS_FAT_H__ */
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