zephyr/include/fs.h

329 lines
8.0 KiB
C

/*
* Copyright (c) 2016 Intel Corporation.
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef _FS_H_
#define _FS_H_
#include <sys/types.h>
#include <fs/fs_interface.h>
#ifdef __cplusplus
extern "C" {
#endif
/* Create a fs_file_t type similar to FILE for familiarity */
typedef struct _fs_file_object fs_file_t;
/* Create a fs_dir_t type similar to DIR for familiarity */
typedef struct _fs_dir_object fs_dir_t;
enum fs_dir_entry_type {
FS_DIR_ENTRY_FILE,
FS_DIR_ENTRY_DIR
};
/**
* @brief File System Functions
* @defgroup data_structures File System Data Structures
* @ingroup file_system
* @{
*/
/** @var fs_file_t
* @brief File object representing an open file
*/
/** @var fs_dir_t
* @brief Directory object representing an open directory
*/
/**
* @brief Structure to receive file or directory information
*
* Used in functions that reads the directory entries to get
* file or directory information.
*
* @param dir_entry_type Whether file or directory
* - FS_DIR_ENTRY_FILE
* - FS_DIR_ENTRY_DIR
* @param name Name of directory or file
* @param size Size of file. 0 if directory
*/
struct fs_dirent {
enum fs_dir_entry_type type;
char name[MAX_FILE_NAME + 1];
size_t size;
};
/**
* @brief Structure to receive volume statistics
*
* Used to retrieve information about total and available space
* in the volume.
*
* @param f_bsize Optimal transfer block size
* @param f_frsize Allocation unit size
* @param f_blocks Size of FS in f_frsize units
* @param f_bfree Number of free blocks
*/
struct fs_statvfs {
unsigned long f_bsize;
unsigned long f_frsize;
unsigned long f_blocks;
unsigned long f_bfree;
};
/**
* @}
*/
#ifndef FS_SEEK_SET
#define FS_SEEK_SET 0 /* Seek from beginning of file. */
#endif
#ifndef FS_SEEK_CUR
#define FS_SEEK_CUR 1 /* Seek from current position. */
#endif
#ifndef FS_SEEK_END
#define FS_SEEK_END 2 /* Seek from end of file. */
#endif
/**
* @brief File System APIs
* @defgroup file_system_api File System APIs
* @ingroup file_system
* @{
*/
/**
* @brief File open
*
* Opens an existing file or create a new one and associates
* a stream with it.
*
* @param zfp Pointer to file object
* @param file_name The name of file to open
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_open(fs_file_t *zfp, const char *file_name);
/**
* @brief File close
*
* Flushes the associated stream and closes
* the file.
*
* @param zfp Pointer to the file object
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_close(fs_file_t *zfp);
/**
* @brief File unlink
*
* Deletes the specified file or directory
*
* @param path Path to the file or directory to delete
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_unlink(const char *path);
/**
* @brief File read
*
* Reads items of data of size bytes long.
*
* @param zfp Pointer to the file object
* @param ptr Pointer to the data buffer
* @param size Number of bytes to be read
*
* @return Number of bytes read. On success, it will be equal to number of
* items requested to be read. Returns less than number of bytes
* requested if there are not enough bytes available in file. Will return
* -ERRNO code on error.
*/
ssize_t fs_read(fs_file_t *zfp, void *ptr, size_t size);
/**
* @brief File write
*
* Writes items of data of size bytes long.
*
* @param zfp Pointer to the file object
* @param ptr Pointer to the data buffer
* @param size Number of bytes to be write
*
* @return Number of bytes written. On success, it will be equal to the number
* of bytes requested to be written. Any other value, indicates an error. Will
* return -ERRNO code on error.
* In the case where -ERRNO is returned, the file pointer will not be
* advanced because it couldn't start the operation.
* In the case where it is able to write, but is not able to complete writing
* all of the requested number of bytes, then it is because the disk got full.
* In that case, it returns less number of bytes written than requested, but
* not a negative -ERRNO value as in regular error case.
*/
ssize_t fs_write(fs_file_t *zfp, const void *ptr, size_t size);
/**
* @brief File seek
*
* Moves the file position to a new location in the file. The offset is added
* to file position based on the 'whence' parameter.
*
* @param zfp Pointer to the file object
* @param offset Relative location to move the file pointer to
* @param whence Relative location from where offset is to be calculated.
* - FS_SEEK_SET = from beginning of file
* - FS_SEEK_CUR = from current position,
* - FS_SEEK_END = from end of file.
*
* @retval 0 Success
* @retval -ERRNO errno code if error.
*/
int fs_seek(fs_file_t *zfp, off_t offset, int whence);
/**
* @brief Get current file position.
*
* Retrieves the current position in the file.
*
* @param zfp Pointer to the file object
*
* @retval position Current position in file
* Current revision does not validate the file object.
*/
off_t fs_tell(fs_file_t *zfp);
/**
* @brief Change the size of an open file
*
* Truncates the file to the new length if it is shorter than the current
* size of the file. Expands the file if the new length is greater than the
* current size of the file. The expanded region would be filled with zeroes.
*
* @note In the case of expansion, if the volume got full during the
* expansion process, the function will expand to the maximum possible length
* and returns success. Caller should check if the expanded size matches the
* requested length.
*
* @param zfp Pointer to the file object
* @param length New size of the file in bytes
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_truncate(fs_file_t *zfp, off_t length);
/**
* @brief Flushes any cached write of an open file
*
* This function can be used to flush the cache of an open file. This can
* be called to ensure data gets written to the storage media immediately.
* This may be done to avoid data loss if power is removed unexpectedly.
* Note that closing a file will cause caches to be flushed correctly so it
* need not be called if the file is being closed.
*
* @param zfp Pointer to the file object
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_sync(fs_file_t *zfp);
/**
* @brief Directory create
*
* Creates a new directory using specified path.
*
* @param path Path to the directory to create
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_mkdir(const char *path);
/**
* @brief Directory open
*
* Opens an existing directory specified by the path.
*
* @param zdp Pointer to the directory object
* @param path Path to the directory to open
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_opendir(fs_dir_t *zdp, const char *path);
/**
* @brief Directory read entry
*
* Reads directory entries of a open directory
*
* @param zdp Pointer to the directory object
* @param entry Pointer to zfs_dirent structure to read the entry into
*
* @retval 0 Success
* @retval -ERRNO errno code if error
* @return In end-of-dir condition, this will return 0 and set
* entry->name[0] = 0
*/
int fs_readdir(fs_dir_t *zdp, struct fs_dirent *entry);
/**
* @brief Directory close
*
* Closes an open directory.
*
* @param zdp Pointer to the directory object
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_closedir(fs_dir_t *zdp);
/**
* @brief File or directory status
*
* Checks the status of a file or directory specified by the path
*
* @param path Path to the file or directory
* @param entry Pointer to zfs_dirent structure to fill if file or directory
* exists.
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_stat(const char *path, struct fs_dirent *entry);
/**
* @brief Retrieves statistics of the file system volume
*
* Returns the total and available space in the file system volume.
*
* @param stat Pointer to zfs_statvfs structure to receive the fs statistics
*
* @retval 0 Success
* @retval -ERRNO errno code if error
*/
int fs_statvfs(struct fs_statvfs *stat);
/**
* @}
*/
#ifdef __cplusplus
}
#endif
#endif /* _FS_H_ */