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[/] [or1k/] [trunk/] [rtems-20020807/] [cpukit/] [libfs/] [src/] [dosfs/] [fat.c] - Rev 1765
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/* * 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> * * @(#) fat.c,v 1.1 2002/02/28 20:43:50 joel Exp */ #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" /* _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, unsigned32 start, unsigned32 offset, unsigned32 count, void *buff ) { int rc = RC_OK; register fat_fs_info_t *fs_info = mt_entry->fs_info; ssize_t cmpltd = 0; unsigned32 blk = start; unsigned32 ofs = offset; bdbuf_buffer *block = NULL; unsigned32 c = 0; while (count > 0) { rc = fat_buf_access(fs_info, blk, FAT_OP_TYPE_READ, &block); if (rc != RC_OK) return rc; 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, unsigned32 start, unsigned32 offset, unsigned32 count, const void *buff) { int rc = RC_OK; fat_fs_info_t *fs_info = mt_entry->fs_info; ssize_t cmpltd = 0; unsigned32 blk = start; unsigned32 ofs = offset; bdbuf_buffer *block = NULL; unsigned32 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 rc; 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, unsigned32 cln, void *buff ) { fat_fs_info_t *fs_info = mt_entry->fs_info; unsigned32 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, unsigned32 cln, const void *buff ) { fat_fs_info_t *fs_info = mt_entry->fs_info; unsigned32 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; unsigned32 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); for (vol->spc_log2 = 0, i = vol->spc; (i & 1) == 0; i >>= 1, vol->spc_log2++); /* * According to M$ White Paper "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, unsigned32 start_cln ) { int rc = RC_OK; ssize_t ret = 0; register fat_fs_info_t *fs_info = mt_entry->fs_info; unsigned32 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 !!! * */ unsigned32 fat_get_unique_ino(rtems_filesystem_mount_table_entry_t *mt_entry) { register fat_fs_info_t *fs_info = mt_entry->fs_info; unsigned32 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, unsigned32 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, unsigned32 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, unsigned32 free_count, unsigned32 next_free ) { ssize_t ret1 = 0, ret2 = 0; register fat_fs_info_t *fs_info = mt_entry->fs_info; unsigned32 le_free_count = 0; unsigned32 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; }