diff options
Diffstat (limited to 'cpukit/libfs/src/dosfs/fat.c')
| -rw-r--r-- | cpukit/libfs/src/dosfs/fat.c | 240 |
1 files changed, 184 insertions, 56 deletions
diff --git a/cpukit/libfs/src/dosfs/fat.c b/cpukit/libfs/src/dosfs/fat.c index 033c15da86..c82bf5ac8b 100644 --- a/cpukit/libfs/src/dosfs/fat.c +++ b/cpukit/libfs/src/dosfs/fat.c @@ -32,10 +32,23 @@ static ssize_t uint32_t cln, void *buff); -static ssize_t - fat_cluster_write(fat_fs_info_t *fs_info, - uint32_t cln, - const void *buff); +static inline uint32_t +fat_cluster_num_to_block_num (const fat_fs_info_t *fs_info, + uint32_t cln) +{ + uint32_t blk; + + if ( (cln == 0) && (fs_info->vol.type & (FAT_FAT12 | FAT_FAT16)) ) + blk = fat_sector_num_to_block_num(fs_info, fs_info->vol.rdir_loc); + else + { + cln -= FAT_RSRVD_CLN; + blk = cln << (fs_info->vol.bpc_log2 - fs_info->vol.bytes_per_block_log2); + blk += fat_sector_num_to_block_num(fs_info, fs_info->vol.data_fsec); + } + + return blk; +} int fat_buf_access(fat_fs_info_t *fs_info, @@ -188,7 +201,44 @@ _fat_block_read( return cmpltd; } -/* _fat_block_write -- +static ssize_t + fat_block_write( + fat_fs_info_t *fs_info, + const uint32_t start_blk, + const uint32_t offset, + const uint32_t count, + const void *buf, + const bool overwrite_block) +{ + int rc = RC_OK; + uint32_t bytes_to_write = MIN(count, (fs_info->vol.bytes_per_block - offset)); + uint8_t *blk_buf; + uint32_t sec_num = fat_block_num_to_sector_num(fs_info, start_blk); + + if (0 < bytes_to_write) + { + if ( overwrite_block + || (bytes_to_write == fs_info->vol.bytes_per_block)) + { + rc = fat_buf_access(fs_info, sec_num, FAT_OP_TYPE_GET, &blk_buf); + } + else + rc = fat_buf_access(fs_info, sec_num, FAT_OP_TYPE_READ, &blk_buf); + + if (RC_OK == rc) + { + memcpy(blk_buf + offset, buf, bytes_to_write); + + fat_buf_mark_modified(fs_info); + } + } + if (RC_OK != rc) + return rc; + else + return bytes_to_write; +} + +/* fat_sector_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 @@ -206,7 +256,7 @@ _fat_block_read( * and errno set appropriately */ ssize_t -_fat_block_write( +fat_sector_write( fat_fs_info_t *fs_info, uint32_t start, uint32_t offset, @@ -243,39 +293,84 @@ _fat_block_write( return cmpltd; } -int -_fat_block_zero( - fat_fs_info_t *fs_info, - uint32_t start, - uint32_t offset, - uint32_t count) +static ssize_t + fat_block_set ( + fat_fs_info_t *fs_info, + const uint32_t start_blk, + const uint32_t offset, + const uint32_t count, + const uint8_t pattern) { - int rc = RC_OK; - uint32_t sec_num = start; - uint32_t ofs = offset; - uint8_t *sec_buf; - uint32_t c = 0; + int rc = RC_OK; + uint32_t bytes_to_write = MIN(count, (fs_info->vol.bytes_per_block - offset)); + uint8_t *blk_buf; + uint32_t sec_num = fat_block_num_to_sector_num(fs_info, start_blk); - while(count > 0) + if (0 < bytes_to_write) { - c = MIN(count, (fs_info->vol.bps - ofs)); - - if (c == fs_info->vol.bps) - rc = fat_buf_access(fs_info, sec_num, FAT_OP_TYPE_GET, &sec_buf); + if (bytes_to_write == fs_info->vol.bytes_per_block) + { + rc = fat_buf_access(fs_info, sec_num, FAT_OP_TYPE_GET, &blk_buf); + } else - rc = fat_buf_access(fs_info, sec_num, FAT_OP_TYPE_READ, &sec_buf); - if (rc != RC_OK) - return -1; + rc = fat_buf_access(fs_info, sec_num, FAT_OP_TYPE_READ, &blk_buf); - memset((block + ofs), 0, c); + if (RC_OK == rc) + { + memset(blk_buf + offset, pattern, bytes_to_write); - fat_buf_mark_modified(fs_info); + fat_buf_mark_modified(fs_info); + } + } + if (RC_OK != rc) + return rc; + else + return bytes_to_write; +} - count -= c; - sec_num++; - ofs = 0; +ssize_t +fat_cluster_set( + fat_fs_info_t *fs_info, + const uint32_t start_cln, + const uint32_t offset, + const uint32_t count, + const uint8_t pattern) +{ + ssize_t rc = RC_OK; + uint32_t bytes_to_write = MIN(count, (fs_info->vol.bpc - offset)); + uint32_t cur_blk = fat_cluster_num_to_block_num(fs_info, start_cln); + uint32_t blocks_in_offset = offset >> fs_info->vol.bytes_per_block_log2; + uint32_t ofs_blk = offset - (blocks_in_offset << fs_info->vol.bytes_per_block_log2); + ssize_t bytes_written = 0; + ssize_t ret; + + cur_blk += blocks_in_offset; + + while ( (RC_OK == rc) + && (0 < bytes_to_write)) + { + uint32_t c = MIN(bytes_to_write, (fs_info->vol.bytes_per_block - ofs_blk)); + + ret = fat_block_set( + fs_info, + cur_blk, + ofs_blk, + c, + pattern); + if (c != ret) + rc = -1; + else + { + bytes_to_write -= ret; + bytes_written += ret; + ++cur_blk; } - return 0; + ofs_blk = 0; + } + if (RC_OK != rc) + return rc; + else + return bytes_written; } /* _fat_block_release -- @@ -322,12 +417,18 @@ fat_cluster_read( } /* fat_cluster_write -- - * wrapper for writting a whole cluster at once + * This function write 'count' bytes to device filesystem is mounted on, + * starts at 'start+offset' position where 'start' computed in clusters + * and 'offset' is offset inside cluster. + * Writing will NOT cross cluster boundaries! * * PARAMETERS: - * fs_info - FS info - * cln - number of cluster to write - * buff - buffer provided by user + * fs_info - FS info + * start_cln - cluster number to start writing to + * offset - offset inside cluster 'start' + * count - count of bytes to write + * buff - buffer provided by user + * overwrite_cluster - true if cluster can get overwritten, false if cluster content must be kept * * RETURNS: * bytes written on success, or -1 if error occured @@ -336,16 +437,50 @@ fat_cluster_read( ssize_t fat_cluster_write( fat_fs_info_t *fs_info, - uint32_t cln, - const void *buff - ) + const uint32_t start_cln, + const uint32_t offset, + const uint32_t count, + const void *buff, + const bool overwrite_cluster) { - uint32_t fsec = 0; - - fsec = fat_cluster_num_to_sector_num(fs_info, cln); - - return _fat_block_write(fs_info, fsec, 0, - fs_info->vol.spc << fs_info->vol.sec_log2, buff); + ssize_t rc = RC_OK; + uint32_t bytes_to_write = MIN(count, (fs_info->vol.bpc - offset)); + uint32_t cur_blk = fat_cluster_num_to_block_num(fs_info, start_cln); + uint32_t blocks_in_offset = (offset >> fs_info->vol.bytes_per_block_log2); + uint32_t ofs_blk = offset - (blocks_in_offset << fs_info->vol.bytes_per_block_log2); + ssize_t bytes_written = 0; + uint8_t *buffer = (uint8_t*)buff; + ssize_t ret; + uint32_t c; + + cur_blk += blocks_in_offset; + + while ( (RC_OK == rc) + && (0 < bytes_to_write)) + { + c = MIN(bytes_to_write, (fs_info->vol.bytes_per_block - ofs_blk)); + + ret = fat_block_write( + fs_info, + cur_blk, + ofs_blk, + c, + &buffer[bytes_written], + overwrite_cluster); + if (c != ret) + rc = -1; + else + { + bytes_to_write -= ret; + bytes_written += ret; + ++cur_blk; + } + ofs_blk = 0; + } + if (RC_OK != rc) + return rc; + else + return bytes_written; } static bool is_cluster_aligned(const fat_vol_t *vol, uint32_t sec_num) @@ -680,7 +815,7 @@ fat_fat32_update_fsinfo_sector(fat_fs_info_t *fs_info) fs_info->vol.free_cls_in_fs_info = free_count; - ret1 = _fat_block_write(fs_info, + ret1 = fat_sector_write(fs_info, fs_info->vol.info_sec, FAT_FSINFO_FREE_CLUSTER_COUNT_OFFSET, sizeof(le_free_count), @@ -693,7 +828,7 @@ fat_fat32_update_fsinfo_sector(fat_fs_info_t *fs_info) fs_info->vol.next_cl_in_fs_info = next_free; - ret2 = _fat_block_write(fs_info, + ret2 = fat_sector_write(fs_info, fs_info->vol.info_sec, FAT_FSINFO_NEXT_FREE_CLUSTER_OFFSET, sizeof(le_next_free), @@ -794,30 +929,23 @@ fat_init_clusters_chain( int rc = RC_OK; ssize_t ret = 0; uint32_t cur_cln = start_cln; - char *buf; - - buf = calloc(fs_info->vol.bpc, sizeof(char)); - if ( buf == NULL ) - rtems_set_errno_and_return_minus_one( EIO ); while ((cur_cln & fs_info->vol.mask) < fs_info->vol.eoc_val) { - ret = fat_cluster_write(fs_info, cur_cln, buf); - if ( ret == -1 ) + ret = fat_cluster_set(fs_info, cur_cln, 0, fs_info->vol.bpc, 0); + if ( ret != fs_info->vol.bpc ) { - free(buf); return -1; } rc = fat_get_fat_cluster(fs_info, cur_cln, &cur_cln); if ( rc != RC_OK ) { - free(buf); return rc; } } - free(buf); + return rc; } |