/* * 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 * * 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 #include /* 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 #include #include #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__ */