0478b5bce4
Squashed commit of the following:
fs/cromfs: Now depends on EXPERIMENTAL because it is not yet verified.
fs/cromfs: This commit brings the CROMFS file system to code complete. Still completely untested. Next steps: Need a tool to generate CROMFS file system images and a test case under apps/
fs/cromfs: Add logic to traverse the in-memory file system nodes.
fs/cromfs: Add initial support for an in-memory, compressed, read-only file system.
127 lines
5.4 KiB
C
127 lines
5.4 KiB
C
/****************************************************************************
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* fs/cromfs/cromfs.h
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*
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* Copyright (C) 2018 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __FS_CROMFS_CROMFS_H
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#define __FS_CROMFS_CROMFS_H 1
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <sys/types.h>
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#include <stdint.h>
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* This structure describes the CROMFS volume. It provides most of the
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* information needed for statfs() including:
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*
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* f_type - Type of filesystem
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* Return cv_magic (CROMFS_MAGIC)
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* f_namelen - Maximum length of filenames
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* Return NAME_MAX
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* f_bsize - Optimal block size for transfers
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* Return cv_bsize, the block size used when file system was
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* compressed
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* f_blocks - Total data blocks in the file system
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* - Return cv_nblocks
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* f_bfree - Free blocks in the file system
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* Return 0
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* f_bavail - Free blocks avail to non-superuser
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* Return 0
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* f_files - Total file nodes in the file system
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* - Return cv_nnodes
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* f_ffree - Free file nodes in the file system
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* Return 0
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*
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* The volume header is followed immediately by the root directory node. An
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* offset to that node is used to permit future variable length data (such as
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* a volumne name) which may intervene.
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*
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* Since this is an in-memory file system, size_t is the most relevant type for
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* internal file system offsets.
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*/
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struct cromfs_volume_s
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{
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uint32_t cv_magic; /* Must be first. Must be CROMFS_MAGIC */
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uint16_t cv_nnodes; /* Total number of nodes in-use */
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uint16_t cv_nblocks; /* Total number of data blocks in-use */
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size_t cv_root; /* Offset to the first node in the root file system */
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size_t cv_fsize; /* Size of the compressed file system image */
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size_t cv_bsize; /* Optimal block size for transfers */
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};
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/* This describes one node in the CROMFS file system. It holds node meta
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* data that provides the information that will be return by stat() or fstat()
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* and also provides the information needed by the CROMFS file system to
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* access the node data.
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*
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* Relationship to struct stat:
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*
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* st_mode - File type, attributes, and access mode bits
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* Return cn_mode from the node structure
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* st_size - Size of file/directory, in bytes
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* Return cn_size from the node structure
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* st_blksize - Block size used for filesystem I/O
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* Return cv_bsize from the volume header.
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* st_blocks - Number of blocks allocated
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* Return (cn_size + (cv_bsize - 1)) / cv_bsize
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* st_atime - Time of last access
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* Return 0
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* st_mtime - Time of last modification
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* Return 0
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* st_ctime - Time of last status change
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* Return 0
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*/
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struct cromfs_node_s
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{
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mode_t cn_mode; /* File type, attributes, and access mode bits */
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size_t cn_name; /* Offset from the beginning of the volume header to the
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* node name string. NUL-terminated. */
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size_t cn_size; /* Size of the uncompressed data (in bytes) */
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size_t cn_peer; /* Offset to next node in this directory (for readdir())*/
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union /* Must be last */
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{
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size_t cn_child; /* Offset to first node in sub-directory (directories only) */
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size_t cn_link; /* Offset to an arbitrary node (for hard link) */
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size_t cn_blocks; /* Offset to first block of compressed data (for read) */
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} u;
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};
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#endif /* __FS_CROMFS_CROMFS_H */ |