Christopher Haster
ed674e8414
Missing seek, but these are the core filesystem operations provided by this filesystem: - Read a file - Append to a file Additional work is needed around freeing the previous file, so right now it's limited to appending to existing files, a real append only filesystem. Unfortunately the overhead of the free list with multiple open files is becoming tricky.
135 lines
2.7 KiB
C
135 lines
2.7 KiB
C
/*
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* The little filesystem
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*
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* Copyright (c) 2017 Christopher Haster
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* Distributed under the MIT license
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*/
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#ifndef LFS_H
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#define LFS_H
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#include "lfs_config.h"
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#include "lfs_bd.h"
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// Data structures
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enum lfs_error {
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LFS_ERROR_OK = 0,
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LFS_ERROR_CORRUPT = -3,
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LFS_ERROR_NO_ENTRY = -4,
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LFS_ERROR_EXISTS = -5,
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LFS_ERROR_NOT_DIR = -6,
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LFS_ERROR_INVALID = -7,
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};
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enum lfs_type {
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LFS_TYPE_REG = 1,
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LFS_TYPE_DIR = 2,
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};
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enum lfs_open_flags {
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LFS_O_RDONLY = 0,
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LFS_O_WRONLY = 1,
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LFS_O_RDWR = 2,
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LFS_O_CREAT = 0x0040,
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LFS_O_EXCL = 0x0080,
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LFS_O_TRUNC = 0x0200,
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LFS_O_APPEND = 0x0400,
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LFS_O_SYNC = 0x1000,
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};
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typedef struct lfs_free {
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lfs_word_t begin;
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lfs_word_t off;
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lfs_word_t end;
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lfs_disk_struct lfs_disk_free {
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lfs_word_t rev;
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lfs_ino_t head;
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lfs_word_t off;
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lfs_word_t end;
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} d;
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} lfs_free_t;
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typedef struct lfs_dir {
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lfs_ino_t pair[2];
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lfs_off_t i;
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lfs_disk_struct lfs_disk_dir {
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lfs_word_t rev;
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lfs_size_t size;
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lfs_ino_t tail[2];
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struct lfs_disk_free free;
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} d;
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} lfs_dir_t;
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typedef struct lfs_entry {
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lfs_ino_t dir[2];
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lfs_off_t off;
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lfs_disk_struct lfs_disk_entry {
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uint16_t type;
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uint16_t len;
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union {
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lfs_disk_struct {
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lfs_ino_t head;
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lfs_size_t size;
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} file;
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lfs_ino_t dir[2];
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} u;
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} d;
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} lfs_entry_t;
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typedef struct lfs_file {
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lfs_ino_t head;
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lfs_size_t size;
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lfs_ino_t wblock;
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lfs_word_t windex;
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lfs_ino_t rblock;
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lfs_word_t rindex;
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lfs_off_t roff;
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struct lfs_entry entry;
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} lfs_file_t;
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typedef struct lfs_superblock {
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lfs_ino_t pair[2];
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lfs_disk_struct lfs_disk_superblock {
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lfs_word_t rev;
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uint32_t size;
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lfs_ino_t root[2];
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char magic[8];
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uint32_t block_size;
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uint32_t block_count;
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} d;
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} lfs_superblock_t;
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// Little filesystem type
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typedef struct lfs {
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lfs_bd_t *bd;
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const struct lfs_bd_ops *ops;
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lfs_ino_t cwd[2];
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lfs_free_t free;
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struct lfs_bd_info info;
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} lfs_t;
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// Functions
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lfs_error_t lfs_create(lfs_t *lfs, lfs_bd_t *bd, const struct lfs_bd_ops *bd_ops);
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lfs_error_t lfs_format(lfs_t *lfs);
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lfs_error_t lfs_mount(lfs_t *lfs);
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lfs_error_t lfs_mkdir(lfs_t *lfs, const char *path);
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lfs_error_t lfs_file_open(lfs_t *lfs, lfs_file_t *file,
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const char *path, int flags);
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lfs_error_t lfs_file_close(lfs_t *lfs, lfs_file_t *file);
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lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
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const void *buffer, lfs_size_t size);
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lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
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void *buffer, lfs_size_t size);
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#endif
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