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|
/*
* The little filesystem
*
* Copyright (c) 2017 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef LFS_H
#define LFS_H
#include <stdint.h>
#include <stdbool.h>
/// Version info ///
// Software library version
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS_VERSION 0x00020000
#define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
#define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >> 0))
// Version of On-disk data structures
// Major (top-nibble), incremented on backwards incompatible changes
// Minor (bottom-nibble), incremented on feature additions
#define LFS_DISK_VERSION 0x00020000
#define LFS_DISK_VERSION_MAJOR (0xffff & (LFS_DISK_VERSION >> 16))
#define LFS_DISK_VERSION_MINOR (0xffff & (LFS_DISK_VERSION >> 0))
/// Definitions ///
// Type definitions
typedef uint32_t lfs_size_t;
typedef uint32_t lfs_off_t;
typedef int32_t lfs_ssize_t;
typedef int32_t lfs_soff_t;
typedef uint32_t lfs_block_t;
// Maximum inline file size in bytes. Large inline files require a larger
// read and prog cache, but if a file can be inline it does not need its own
// data block. LFS_ATTRS_MAX + LFS_INLINE_MAX must be <= 0xffff. Stored in
// superblock and must be respected by other littlefs drivers.
#ifndef LFS_INLINE_MAX
#define LFS_INLINE_MAX 0x3ff
#endif
// Maximum size of all attributes per file in bytes, may be redefined but a
// a smaller LFS_ATTRS_MAX has no benefit. LFS_ATTRS_MAX + LFS_INLINE_MAX
// must be <= 0xffff. Stored in superblock and must be respected by other
// littlefs drivers.
#ifndef LFS_ATTRS_MAX
#define LFS_ATTRS_MAX 0x3f
#endif
// Max name size in bytes, may be redefined to reduce the size of the
// info struct. Stored in superblock and must be respected by other
// littlefs drivers.
#ifndef LFS_NAME_MAX
#define LFS_NAME_MAX 0xff
#endif
// Possible error codes, these are negative to allow
// valid positive return values
enum lfs_error {
LFS_ERR_OK = 0, // No error
LFS_ERR_IO = -5, // Error during device operation
LFS_ERR_CORRUPT = -52, // Corrupted
LFS_ERR_NOENT = -2, // No directory entry
LFS_ERR_EXIST = -17, // Entry already exists
LFS_ERR_NOTDIR = -20, // Entry is not a dir
LFS_ERR_ISDIR = -21, // Entry is a dir
LFS_ERR_NOTEMPTY = -39, // Dir is not empty
LFS_ERR_BADF = -9, // Bad file number
LFS_ERR_INVAL = -22, // Invalid parameter
LFS_ERR_NOSPC = -28, // No space left on device
LFS_ERR_NOMEM = -12, // No more memory available
LFS_ERR_NAMETOOLONG = -36, // File name too long
LFS_ERR_NODATA = -61, // No data/attr available
LFS_ERR_RANGE = -34, // Result not representable
};
// File types
enum lfs_type {
// file types
LFS_TYPE_REG = 0x001,
LFS_TYPE_DIR = 0x002,
// internally used types
LFS_TYPE_USER = 0x100,
LFS_TYPE_SUPERBLOCK = 0x010,
LFS_TYPE_NAME = 0x000,
LFS_TYPE_DELETE = 0x03f,
LFS_TYPE_STRUCT = 0x040,
LFS_TYPE_GLOBALS = 0x080,
LFS_TYPE_TAIL = 0x0c0,
LFS_TYPE_SOFTTAIL = 0x0c0,
LFS_TYPE_HARDTAIL = 0x0c1,
LFS_TYPE_CRC = 0x0ff,
LFS_STRUCT_INLINE = 0x040,
LFS_STRUCT_CTZ = 0x041,
LFS_STRUCT_DIR = 0x042,
// internal chip sources
LFS_FROM_REGION = 0x000,
LFS_FROM_DISK = 0x200,
LFS_FROM_MOVE = 0x030,
};
// File open flags
enum lfs_open_flags {
// open flags
LFS_O_RDONLY = 1, // Open a file as read only
LFS_O_WRONLY = 2, // Open a file as write only
LFS_O_RDWR = 3, // Open a file as read and write
LFS_O_CREAT = 0x0100, // Create a file if it does not exist
LFS_O_EXCL = 0x0200, // Fail if a file already exists
LFS_O_TRUNC = 0x0400, // Truncate the existing file to zero size
LFS_O_APPEND = 0x0800, // Move to end of file on every write
// internally used flags
LFS_F_DIRTY = 0x010000, // File does not match storage
LFS_F_WRITING = 0x020000, // File has been written since last flush
LFS_F_READING = 0x040000, // File has been read since last flush
LFS_F_ERRED = 0x080000, // An error occured during write
LFS_F_INLINE = 0x100000, // Currently inlined in directory entry
};
// File seek flags
enum lfs_whence_flags {
LFS_SEEK_SET = 0, // Seek relative to an absolute position
LFS_SEEK_CUR = 1, // Seek relative to the current file position
LFS_SEEK_END = 2, // Seek relative to the end of the file
};
// Configuration provided during initialization of the littlefs
struct lfs_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 lfs_config *c, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_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 LFS_ERR_CORRUPT if the block should be considered bad.
int (*prog)(const struct lfs_config *c, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_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 LFS_ERR_CORRUPT if the block should be considered bad.
int (*erase)(const struct lfs_config *c, lfs_block_t block);
// Sync the state of the underlying block device. Negative error codes
// are propogated to the user.
int (*sync)(const struct lfs_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.
lfs_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.
lfs_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.
lfs_size_t block_size;
// Number of erasable blocks on the device.
lfs_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.
lfs_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 upper limit on inlined files in bytes. Large inline files
// require a larger read and prog cache, but if a file can be inlined it
// does not need its own data block. Must be smaller than the read size
// and prog size. Defaults to min(LFS_INLINE_MAX, read_size) when zero.
// Stored in superblock and must be respected by other littlefs drivers.
lfs_size_t inline_size;
// Optional upper limit on attributes per file in bytes. No downside for
// larger attributes size but must be less than LFS_ATTRS_MAX. Defaults to
// LFS_ATTRS_MAX when zero.Stored in superblock and must be respected by
// other littlefs drivers.
lfs_size_t attrs_size;
// Optional upper limit on length of file names in bytes. No downside for
// larger names except the size of the info struct which is controlled by
// the LFS_NAME_MAX define. Defaults to LFS_NAME_MAX when zero. Stored in
// superblock and must be respected by other littlefs drivers.
lfs_size_t name_size;
};
// File info structure
struct lfs_info {
// Type of the file, either LFS_TYPE_REG or LFS_TYPE_DIR
uint8_t type;
// Size of the file, only valid for REG files
lfs_size_t size;
// Name of the file stored as a null-terminated string
char name[LFS_NAME_MAX+1];
};
// Custom attribute structure
struct lfs_attr {
// Type of attribute, provided by user and used to identify the attribute
uint8_t type;
// Pointer to buffer containing the attribute
void *buffer;
// Size of attribute in bytes, limited to LFS_ATTRS_MAX
lfs_size_t size;
};
/// littlefs data structures ///
typedef uint32_t lfs_tag_t;
typedef struct lfs_mattr {
lfs_tag_t tag;
union {
void *buffer;
lfs_block_t pair[2];
struct {
lfs_block_t head;
lfs_size_t size;
} ctz;
struct {
lfs_block_t block;
lfs_off_t off;
} d;
struct lfs_mdir *dir;
} u;
} lfs_mattr_t;
typedef struct lfs_mattrlist {
lfs_mattr_t e;
struct lfs_mattrlist *next;
} lfs_mattrlist_t;
//typedef struct lfs_entry {
// lfs_block_t pair[2];
// uint16_t id;
//} lfs_entry_t;
typedef struct lfs_globals {
struct lfs_move {
lfs_block_t pair[2];
uint16_t id;
} move;
} lfs_globals_t;
typedef struct lfs_mdir {
lfs_block_t pair[2];
lfs_block_t tail[2];
uint32_t rev;
lfs_off_t off;
uint32_t etag;
uint16_t count;
bool erased;
bool split;
bool stop_at_commit; // TODO hmmm
lfs_globals_t globals;
} lfs_mdir_t;
typedef struct lfs_cache {
lfs_block_t block;
lfs_off_t off;
uint8_t *buffer;
} lfs_cache_t;
typedef struct lfs_file {
struct lfs_file *next;
lfs_block_t pair[2];
uint16_t id;
lfs_block_t head;
lfs_size_t size;
uint32_t flags;
lfs_off_t pos;
lfs_block_t block;
lfs_off_t off;
lfs_cache_t cache;
lfs_mattrlist_t *attrs;
} lfs_file_t;
typedef struct lfs_dir {
struct lfs_dir *next;
struct lfs_mdir m;
lfs_block_t head[2];
uint16_t id;
lfs_off_t pos;
} lfs_dir_t;
typedef struct lfs_superblock {
char magic[8];
uint32_t version;
lfs_size_t block_size;
lfs_size_t block_count;
lfs_size_t inline_size;
lfs_size_t attrs_size;
lfs_size_t name_size;
} lfs_superblock_t;
typedef struct lfs_free {
lfs_block_t off;
lfs_block_t size;
lfs_block_t i;
lfs_block_t ack;
uint32_t *buffer;
} lfs_free_t;
// The littlefs type
typedef struct lfs {
const struct lfs_config *cfg;
lfs_block_t root[2];
lfs_file_t *files;
lfs_dir_t *dirs;
lfs_cache_t rcache;
lfs_cache_t pcache;
lfs_free_t free;
bool deorphaned;
lfs_globals_t globals;
lfs_globals_t diff;
lfs_size_t inline_size;
lfs_size_t attrs_size;
lfs_size_t name_size;
} lfs_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.
//
// Returns a negative error code on failure.
int lfs_format(lfs_t *lfs, const struct lfs_config *config);
// Mounts a littlefs
//
// Requires a littlefs object and config struct. Multiple filesystems
// may be mounted simultaneously with multiple littlefs objects. Both
// lfs and config must be allocated while mounted.
//
// Returns a negative error code on failure.
int lfs_mount(lfs_t *lfs, const struct lfs_config *config);
// Unmounts a littlefs
//
// Does nothing besides releasing any allocated resources.
// Returns a negative error code on failure.
int lfs_unmount(lfs_t *lfs);
/// General operations ///
// Removes a file or directory
//
// If removing a directory, the directory must be empty.
// Returns a negative error code on failure.
int lfs_remove(lfs_t *lfs, 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 lfs_rename(lfs_t *lfs, 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 lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info);
// Get custom attributes
//
// Attributes are looked up based on the type id. If the stored attribute is
// smaller than the buffer, it is padded with zeros. It the stored attribute
// is larger than the buffer, LFS_ERR_RANGE is returned.
//
// Returns a negative error code on failure.
int lfs_getattrs(lfs_t *lfs, const char *path,
const struct lfs_attr *attrs, int count);
// Set custom attributes
//
// The array of attributes will be used to update the attributes stored on
// disk based on their type id. Unspecified attributes are left unmodified.
// Specifying an attribute with zero size deletes the attribute.
//
// Returns a negative error code on failure.
int lfs_setattrs(lfs_t *lfs, const char *path,
const struct lfs_attr *attrs, int count);
/// File operations ///
// Open a file
//
// The mode that the file is opened in is determined
// by the flags, which are values from the enum lfs_open_flags
// that are bitwise-ored together.
//
// Returns a negative error code on failure.
int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags);
// 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 lfs_file_close(lfs_t *lfs, lfs_file_t *file);
// Synchronize a file on storage
//
// Any pending writes are written out to storage.
// Returns a negative error code on failure.
int lfs_file_sync(lfs_t *lfs, lfs_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.
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_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.
lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_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.
lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence);
// Truncates the size of the file to the specified size
//
// Returns a negative error code on failure.
int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size);
// Return the position of the file
//
// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_CUR)
// Returns the position of the file, or a negative error code on failure.
lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file);
// Change the position of the file to the beginning of the file
//
// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_CUR)
// Returns a negative error code on failure.
int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file);
// Return the size of the file
//
// Similar to lfs_file_seek(lfs, file, 0, LFS_SEEK_END)
// Returns the size of the file, or a negative error code on failure.
lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file);
// Get custom attributes attached to a file
//
// Attributes are looked up based on the type id. If the stored attribute is
// smaller than the buffer, it is padded with zeros. It the stored attribute
// is larger than the buffer, LFS_ERR_RANGE is returned.
//
// Returns a negative error code on failure.
int lfs_file_getattrs(lfs_t *lfs, lfs_file_t *file,
const struct lfs_attr *attrs, int count);
// Set custom attributes on a file
//
// The array of attributes will be used to update the attributes stored on
// disk based on their type id. Unspecified attributes are left unmodified.
// Specifying an attribute with zero size deletes the attribute.
//
// Note: Attributes are not written out until a call to lfs_file_sync
// or lfs_file_close and must be allocated until the file is closed or
// lfs_file_setattrs is called with a count of zero.
//
// Returns a negative error code on failure.
int lfs_file_setattrs(lfs_t *lfs, lfs_file_t *file,
const struct lfs_attr *attrs, int count);
/// Directory operations ///
// Create a directory
//
// Returns a negative error code on failure.
int lfs_mkdir(lfs_t *lfs, 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 lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path);
// Close a directory
//
// Releases any allocated resources.
// Returns a negative error code on failure.
int lfs_dir_close(lfs_t *lfs, lfs_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 lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_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 lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_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.
lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir);
// Change the position of the directory to the beginning of the directory
//
// Returns a negative error code on failure.
int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir);
/// Filesystem filesystem operations ///
// Get custom attributes on the filesystem
//
// Attributes are looked up based on the type id. If the stored attribute is
// smaller than the buffer, it is padded with zeros. It the stored attribute
// is larger than the buffer, LFS_ERR_RANGE is returned.
//
// Returns a negative error code on failure.
int lfs_fs_getattrs(lfs_t *lfs, const struct lfs_attr *attrs, int count);
// Set custom attributes on the filesystem
//
// The array of attributes will be used to update the attributes stored on
// disk based on their type id. Unspecified attributes are left unmodified.
// Specifying an attribute with zero size deletes the attribute.
//
// Note: Filesystem level attributes are not available for wear-leveling
//
// Returns a negative error code on failure.
int lfs_fs_setattrs(lfs_t *lfs, const struct lfs_attr *attrs, int count);
// Finds the current size of the filesystem
//
// Note: Result is best effort. If files share COW structures, the returned
// size may be larger than the filesystem actually is.
//
// Returns the number of allocated blocks, or a negative error code on failure.
lfs_ssize_t lfs_fs_size(lfs_t *lfs);
/// 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 lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_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 lfs_deorphan(lfs_t *lfs);
#endif
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