circuitpython/lib/littlefs/lfs1.h

502 lines
15 KiB
C

/*
* The little filesystem
*
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef LFS1_H
#define LFS1_H
#include <stdint.h>
#include <stdbool.h>
#ifdef __cplusplus
extern "C"
{
#endif
/// Version info ///
// Software library version
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS1_VERSION 0x00010007
#define LFS1_VERSION_MAJOR (0xffff & (LFS1_VERSION >> 16))
#define LFS1_VERSION_MINOR (0xffff & (LFS1_VERSION >> 0))
// Version of On-disk data structures
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS1_DISK_VERSION 0x00010001
#define LFS1_DISK_VERSION_MAJOR (0xffff & (LFS1_DISK_VERSION >> 16))
#define LFS1_DISK_VERSION_MINOR (0xffff & (LFS1_DISK_VERSION >> 0))
/// Definitions ///
// Type definitions
typedef uint32_t lfs1_size_t;
typedef uint32_t lfs1_off_t;
typedef int32_t lfs1_ssize_t;
typedef int32_t lfs1_soff_t;
typedef uint32_t lfs1_block_t;
// Max name size in bytes
#ifndef LFS1_NAME_MAX
#define LFS1_NAME_MAX 255
#endif
// Max file size in bytes
#ifndef LFS1_FILE_MAX
#define LFS1_FILE_MAX 2147483647
#endif
// Possible error codes, these are negative to allow
// valid positive return values
enum lfs1_error {
LFS1_ERR_OK = 0, // No error
LFS1_ERR_IO = -5, // Error during device operation
LFS1_ERR_CORRUPT = -52, // Corrupted
LFS1_ERR_NOENT = -2, // No directory entry
LFS1_ERR_EXIST = -17, // Entry already exists
LFS1_ERR_NOTDIR = -20, // Entry is not a dir
LFS1_ERR_ISDIR = -21, // Entry is a dir
LFS1_ERR_NOTEMPTY = -39, // Dir is not empty
LFS1_ERR_BADF = -9, // Bad file number
LFS1_ERR_FBIG = -27, // File too large
LFS1_ERR_INVAL = -22, // Invalid parameter
LFS1_ERR_NOSPC = -28, // No space left on device
LFS1_ERR_NOMEM = -12, // No more memory available
};
// File types
enum lfs1_type {
LFS1_TYPE_REG = 0x11,
LFS1_TYPE_DIR = 0x22,
LFS1_TYPE_SUPERBLOCK = 0x2e,
};
// File open flags
enum lfs1_open_flags {
// open flags
LFS1_O_RDONLY = 1, // Open a file as read only
LFS1_O_WRONLY = 2, // Open a file as write only
LFS1_O_RDWR = 3, // Open a file as read and write
LFS1_O_CREAT = 0x0100, // Create a file if it does not exist
LFS1_O_EXCL = 0x0200, // Fail if a file already exists
LFS1_O_TRUNC = 0x0400, // Truncate the existing file to zero size
LFS1_O_APPEND = 0x0800, // Move to end of file on every write
// internally used flags
LFS1_F_DIRTY = 0x10000, // File does not match storage
LFS1_F_WRITING = 0x20000, // File has been written since last flush
LFS1_F_READING = 0x40000, // File has been read since last flush
LFS1_F_ERRED = 0x80000, // An error occured during write
};
// File seek flags
enum lfs1_whence_flags {
LFS1_SEEK_SET = 0, // Seek relative to an absolute position
LFS1_SEEK_CUR = 1, // Seek relative to the current file position
LFS1_SEEK_END = 2, // Seek relative to the end of the file
};
// Configuration provided during initialization of the littlefs
struct lfs1_config {
// Opaque user provided context that can be used to pass
// information to the block device operations
void *context;
// Read a region in a block. Negative error codes are propogated
// to the user.
int (*read)(const struct lfs1_config *c, lfs1_block_t block,
lfs1_off_t off, void *buffer, lfs1_size_t size);
// Program a region in a block. The block must have previously
// been erased. Negative error codes are propogated to the user.
// May return LFS1_ERR_CORRUPT if the block should be considered bad.
int (*prog)(const struct lfs1_config *c, lfs1_block_t block,
lfs1_off_t off, const void *buffer, lfs1_size_t size);
// Erase a block. A block must be erased before being programmed.
// The state of an erased block is undefined. Negative error codes
// are propogated to the user.
// May return LFS1_ERR_CORRUPT if the block should be considered bad.
int (*erase)(const struct lfs1_config *c, lfs1_block_t block);
// Sync the state of the underlying block device. Negative error codes
// are propogated to the user.
int (*sync)(const struct lfs1_config *c);
// Minimum size of a block read. This determines the size of read buffers.
// This may be larger than the physical read size to improve performance
// by caching more of the block device.
lfs1_size_t read_size;
// Minimum size of a block program. This determines the size of program
// buffers. This may be larger than the physical program size to improve
// performance by caching more of the block device.
// Must be a multiple of the read size.
lfs1_size_t prog_size;
// Size of an erasable block. This does not impact ram consumption and
// may be larger than the physical erase size. However, this should be
// kept small as each file currently takes up an entire block.
// Must be a multiple of the program size.
lfs1_size_t block_size;
// Number of erasable blocks on the device.
lfs1_size_t block_count;
// Number of blocks to lookahead during block allocation. A larger
// lookahead reduces the number of passes required to allocate a block.
// The lookahead buffer requires only 1 bit per block so it can be quite
// large with little ram impact. Should be a multiple of 32.
lfs1_size_t lookahead;
// Optional, statically allocated read buffer. Must be read sized.
void *read_buffer;
// Optional, statically allocated program buffer. Must be program sized.
void *prog_buffer;
// Optional, statically allocated lookahead buffer. Must be 1 bit per
// lookahead block.
void *lookahead_buffer;
// Optional, statically allocated buffer for files. Must be program sized.
// If enabled, only one file may be opened at a time.
void *file_buffer;
};
// Optional configuration provided during lfs1_file_opencfg
struct lfs1_file_config {
// Optional, statically allocated buffer for files. Must be program sized.
// If NULL, malloc will be used by default.
void *buffer;
};
// File info structure
struct lfs1_info {
// Type of the file, either LFS1_TYPE_REG or LFS1_TYPE_DIR
uint8_t type;
// Size of the file, only valid for REG files
lfs1_size_t size;
// Name of the file stored as a null-terminated string
char name[LFS1_NAME_MAX+1];
};
/// littlefs data structures ///
typedef struct lfs1_entry {
lfs1_off_t off;
struct lfs1_disk_entry {
uint8_t type;
uint8_t elen;
uint8_t alen;
uint8_t nlen;
union {
struct {
lfs1_block_t head;
lfs1_size_t size;
} file;
lfs1_block_t dir[2];
} u;
} d;
} lfs1_entry_t;
typedef struct lfs1_cache {
lfs1_block_t block;
lfs1_off_t off;
uint8_t *buffer;
} lfs1_cache_t;
typedef struct lfs1_file {
struct lfs1_file *next;
lfs1_block_t pair[2];
lfs1_off_t poff;
lfs1_block_t head;
lfs1_size_t size;
const struct lfs1_file_config *cfg;
uint32_t flags;
lfs1_off_t pos;
lfs1_block_t block;
lfs1_off_t off;
lfs1_cache_t cache;
} lfs1_file_t;
typedef struct lfs1_dir {
struct lfs1_dir *next;
lfs1_block_t pair[2];
lfs1_off_t off;
lfs1_block_t head[2];
lfs1_off_t pos;
struct lfs1_disk_dir {
uint32_t rev;
lfs1_size_t size;
lfs1_block_t tail[2];
} d;
} lfs1_dir_t;
typedef struct lfs1_superblock {
lfs1_off_t off;
struct lfs1_disk_superblock {
uint8_t type;
uint8_t elen;
uint8_t alen;
uint8_t nlen;
lfs1_block_t root[2];
uint32_t block_size;
uint32_t block_count;
uint32_t version;
char magic[8];
} d;
} lfs1_superblock_t;
typedef struct lfs1_free {
lfs1_block_t off;
lfs1_block_t size;
lfs1_block_t i;
lfs1_block_t ack;
uint32_t *buffer;
} lfs1_free_t;
// The littlefs type
typedef struct lfs1 {
const struct lfs1_config *cfg;
lfs1_block_t root[2];
lfs1_file_t *files;
lfs1_dir_t *dirs;
lfs1_cache_t rcache;
lfs1_cache_t pcache;
lfs1_free_t free;
bool deorphaned;
bool moving;
} lfs1_t;
/// Filesystem functions ///
// Format a block device with the littlefs
//
// Requires a littlefs object and config struct. This clobbers the littlefs
// object, and does not leave the filesystem mounted. The config struct must
// be zeroed for defaults and backwards compatibility.
//
// Returns a negative error code on failure.
int lfs1_format(lfs1_t *lfs1, const struct lfs1_config *config);
// Mounts a littlefs
//
// Requires a littlefs object and config struct. Multiple filesystems
// may be mounted simultaneously with multiple littlefs objects. Both
// lfs1 and config must be allocated while mounted. The config struct must
// be zeroed for defaults and backwards compatibility.
//
// Returns a negative error code on failure.
int lfs1_mount(lfs1_t *lfs1, const struct lfs1_config *config);
// Unmounts a littlefs
//
// Does nothing besides releasing any allocated resources.
// Returns a negative error code on failure.
int lfs1_unmount(lfs1_t *lfs1);
/// General operations ///
// Removes a file or directory
//
// If removing a directory, the directory must be empty.
// Returns a negative error code on failure.
int lfs1_remove(lfs1_t *lfs1, const char *path);
// Rename or move a file or directory
//
// If the destination exists, it must match the source in type.
// If the destination is a directory, the directory must be empty.
//
// Returns a negative error code on failure.
int lfs1_rename(lfs1_t *lfs1, const char *oldpath, const char *newpath);
// Find info about a file or directory
//
// Fills out the info structure, based on the specified file or directory.
// Returns a negative error code on failure.
int lfs1_stat(lfs1_t *lfs1, const char *path, struct lfs1_info *info);
/// File operations ///
// Open a file
//
// The mode that the file is opened in is determined by the flags, which
// are values from the enum lfs1_open_flags that are bitwise-ored together.
//
// Returns a negative error code on failure.
int lfs1_file_open(lfs1_t *lfs1, lfs1_file_t *file,
const char *path, int flags);
// Open a file with extra configuration
//
// The mode that the file is opened in is determined by the flags, which
// are values from the enum lfs1_open_flags that are bitwise-ored together.
//
// The config struct provides additional config options per file as described
// above. The config struct must be allocated while the file is open, and the
// config struct must be zeroed for defaults and backwards compatibility.
//
// Returns a negative error code on failure.
int lfs1_file_opencfg(lfs1_t *lfs1, lfs1_file_t *file,
const char *path, int flags,
const struct lfs1_file_config *config);
// Close a file
//
// Any pending writes are written out to storage as though
// sync had been called and releases any allocated resources.
//
// Returns a negative error code on failure.
int lfs1_file_close(lfs1_t *lfs1, lfs1_file_t *file);
// Synchronize a file on storage
//
// Any pending writes are written out to storage.
// Returns a negative error code on failure.
int lfs1_file_sync(lfs1_t *lfs1, lfs1_file_t *file);
// Read data from file
//
// Takes a buffer and size indicating where to store the read data.
// Returns the number of bytes read, or a negative error code on failure.
lfs1_ssize_t lfs1_file_read(lfs1_t *lfs1, lfs1_file_t *file,
void *buffer, lfs1_size_t size);
// Write data to file
//
// Takes a buffer and size indicating the data to write. The file will not
// actually be updated on the storage until either sync or close is called.
//
// Returns the number of bytes written, or a negative error code on failure.
lfs1_ssize_t lfs1_file_write(lfs1_t *lfs1, lfs1_file_t *file,
const void *buffer, lfs1_size_t size);
// Change the position of the file
//
// The change in position is determined by the offset and whence flag.
// Returns the old position of the file, or a negative error code on failure.
lfs1_soff_t lfs1_file_seek(lfs1_t *lfs1, lfs1_file_t *file,
lfs1_soff_t off, int whence);
// Truncates the size of the file to the specified size
//
// Returns a negative error code on failure.
int lfs1_file_truncate(lfs1_t *lfs1, lfs1_file_t *file, lfs1_off_t size);
// Return the position of the file
//
// Equivalent to lfs1_file_seek(lfs1, file, 0, LFS1_SEEK_CUR)
// Returns the position of the file, or a negative error code on failure.
lfs1_soff_t lfs1_file_tell(lfs1_t *lfs1, lfs1_file_t *file);
// Change the position of the file to the beginning of the file
//
// Equivalent to lfs1_file_seek(lfs1, file, 0, LFS1_SEEK_CUR)
// Returns a negative error code on failure.
int lfs1_file_rewind(lfs1_t *lfs1, lfs1_file_t *file);
// Return the size of the file
//
// Similar to lfs1_file_seek(lfs1, file, 0, LFS1_SEEK_END)
// Returns the size of the file, or a negative error code on failure.
lfs1_soff_t lfs1_file_size(lfs1_t *lfs1, lfs1_file_t *file);
/// Directory operations ///
// Create a directory
//
// Returns a negative error code on failure.
int lfs1_mkdir(lfs1_t *lfs1, const char *path);
// Open a directory
//
// Once open a directory can be used with read to iterate over files.
// Returns a negative error code on failure.
int lfs1_dir_open(lfs1_t *lfs1, lfs1_dir_t *dir, const char *path);
// Close a directory
//
// Releases any allocated resources.
// Returns a negative error code on failure.
int lfs1_dir_close(lfs1_t *lfs1, lfs1_dir_t *dir);
// Read an entry in the directory
//
// Fills out the info structure, based on the specified file or directory.
// Returns a negative error code on failure.
int lfs1_dir_read(lfs1_t *lfs1, lfs1_dir_t *dir, struct lfs1_info *info);
// Change the position of the directory
//
// The new off must be a value previous returned from tell and specifies
// an absolute offset in the directory seek.
//
// Returns a negative error code on failure.
int lfs1_dir_seek(lfs1_t *lfs1, lfs1_dir_t *dir, lfs1_off_t off);
// Return the position of the directory
//
// The returned offset is only meant to be consumed by seek and may not make
// sense, but does indicate the current position in the directory iteration.
//
// Returns the position of the directory, or a negative error code on failure.
lfs1_soff_t lfs1_dir_tell(lfs1_t *lfs1, lfs1_dir_t *dir);
// Change the position of the directory to the beginning of the directory
//
// Returns a negative error code on failure.
int lfs1_dir_rewind(lfs1_t *lfs1, lfs1_dir_t *dir);
/// Miscellaneous littlefs specific operations ///
// Traverse through all blocks in use by the filesystem
//
// The provided callback will be called with each block address that is
// currently in use by the filesystem. This can be used to determine which
// blocks are in use or how much of the storage is available.
//
// Returns a negative error code on failure.
int lfs1_traverse(lfs1_t *lfs1, int (*cb)(void*, lfs1_block_t), void *data);
// Prunes any recoverable errors that may have occured in the filesystem
//
// Not needed to be called by user unless an operation is interrupted
// but the filesystem is still mounted. This is already called on first
// allocation.
//
// Returns a negative error code on failure.
int lfs1_deorphan(lfs1_t *lfs1);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif