esp-idf/components/vfs/include/esp_vfs.h

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6.8 KiB
C

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// 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 __ESP_VFS_H__
#define __ESP_VFS_H__
#include <stdint.h>
#include <stddef.h>
#include "esp_err.h"
#include <sys/types.h>
#include <sys/reent.h>
#include <sys/stat.h>
#include <dirent.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* Maximum length of path prefix (not including zero terminator)
*/
#define ESP_VFS_PATH_MAX 15
/**
* Default value of flags member in esp_vfs_t structure.
*/
#define ESP_VFS_FLAG_DEFAULT 0
/**
* Flag which indicates that FS needs extra context pointer in syscalls.
*/
#define ESP_VFS_FLAG_CONTEXT_PTR 1
/**
* @brief VFS definition structure
*
* This structure should be filled with pointers to corresponding
* FS driver functions.
*
* If the FS implementation has an option to use certain offset for
* all file descriptors, this value should be passed into fd_offset
* field. Otherwise VFS component will translate all FDs to start
* at zero offset.
*
* Some FS implementations expect some state (e.g. pointer to some structure)
* to be passed in as a first argument. For these implementations,
* populate the members of this structure which have _p suffix, set
* flags member to ESP_VFS_FLAG_CONTEXT_PTR and provide the context pointer
* to esp_vfs_register function.
* If the implementation doesn't use this extra argument, populate the
* members without _p suffix and set flags member to ESP_VFS_FLAG_DEFAULT.
*
* If the FS driver doesn't provide some of the functions, set corresponding
* members to NULL.
*/
typedef struct
{
int fd_offset; /*!< file descriptor offset, determined by the FS driver */
int flags; /*!< ESP_VFS_FLAG_CONTEXT_PTR or ESP_VFS_FLAG_DEFAULT */
union {
ssize_t (*write_p)(void* p, int fd, const void * data, size_t size);
ssize_t (*write)(int fd, const void * data, size_t size);
};
union {
off_t (*lseek_p)(void* p, int fd, off_t size, int mode);
off_t (*lseek)(int fd, off_t size, int mode);
};
union {
ssize_t (*read_p)(void* ctx, int fd, void * dst, size_t size);
ssize_t (*read)(int fd, void * dst, size_t size);
};
union {
int (*open_p)(void* ctx, const char * path, int flags, int mode);
int (*open)(const char * path, int flags, int mode);
};
union {
int (*close_p)(void* ctx, int fd);
int (*close)(int fd);
};
union {
int (*fstat_p)(void* ctx, int fd, struct stat * st);
int (*fstat)(int fd, struct stat * st);
};
union {
int (*stat_p)(void* ctx, const char * path, struct stat * st);
int (*stat)(const char * path, struct stat * st);
};
union {
int (*link_p)(void* ctx, const char* n1, const char* n2);
int (*link)(const char* n1, const char* n2);
};
union {
int (*unlink_p)(void* ctx, const char *path);
int (*unlink)(const char *path);
};
union {
int (*rename_p)(void* ctx, const char *src, const char *dst);
int (*rename)(const char *src, const char *dst);
};
union {
DIR* (*opendir_p)(void* ctx, const char* name);
DIR* (*opendir)(const char* name);
};
union {
struct dirent* (*readdir_p)(void* ctx, DIR* pdir);
struct dirent* (*readdir)(DIR* pdir);
};
union {
int (*readdir_r_p)(void* ctx, DIR* pdir, struct dirent* entry, struct dirent** out_dirent);
int (*readdir_r)(DIR* pdir, struct dirent* entry, struct dirent** out_dirent);
};
union {
long (*telldir_p)(void* ctx, DIR* pdir);
long (*telldir)(DIR* pdir);
};
union {
void (*seekdir_p)(void* ctx, DIR* pdir, long offset);
void (*seekdir)(DIR* pdir, long offset);
};
union {
int (*closedir_p)(void* ctx, DIR* pdir);
int (*closedir)(DIR* pdir);
};
union {
int (*mkdir_p)(void* ctx, const char* name, mode_t mode);
int (*mkdir)(const char* name, mode_t mode);
};
union {
int (*rmdir_p)(void* ctx, const char* name);
int (*rmdir)(const char* name);
};
} esp_vfs_t;
/**
* Register a virtual filesystem for given path prefix.
*
* @param base_path file path prefix associated with the filesystem.
* Must be a zero-terminated C string, up to ESP_VFS_PATH_MAX
* characters long, and at least 2 characters long.
* Name must start with a "/" and must not end with "/".
* For example, "/data" or "/dev/spi" are valid.
* These VFSes would then be called to handle file paths such as
* "/data/myfile.txt" or "/dev/spi/0".
* @param vfs Pointer to esp_vfs_t, a structure which maps syscalls to
* the filesystem driver functions. VFS component doesn't
* assume ownership of this pointer.
* @param ctx If vfs->flags has ESP_VFS_FLAG_CONTEXT_PTR set, a pointer
* which should be passed to VFS functions. Otherwise, NULL.
*
* @return ESP_OK if successful, ESP_ERR_NO_MEM if too many VFSes are
* registered.
*/
esp_err_t esp_vfs_register(const char* base_path, const esp_vfs_t* vfs, void* ctx);
/**
* Unregister a virtual filesystem for given path prefix
*
* @param base_path file prefix previously used in esp_vfs_register call
* @return ESP_OK if successful, ESP_ERR_INVALID_STATE if VFS for given prefix
* hasn't been registered
*/
esp_err_t esp_vfs_unregister(const char* base_path);
/**
* These functions are to be used in newlib syscall table. They will be called by
* newlib when it needs to use any of the syscalls.
*/
/**@{*/
ssize_t esp_vfs_write(struct _reent *r, int fd, const void * data, size_t size);
off_t esp_vfs_lseek(struct _reent *r, int fd, off_t size, int mode);
ssize_t esp_vfs_read(struct _reent *r, int fd, void * dst, size_t size);
int esp_vfs_open(struct _reent *r, const char * path, int flags, int mode);
int esp_vfs_close(struct _reent *r, int fd);
int esp_vfs_fstat(struct _reent *r, int fd, struct stat * st);
int esp_vfs_stat(struct _reent *r, const char * path, struct stat * st);
int esp_vfs_link(struct _reent *r, const char* n1, const char* n2);
int esp_vfs_unlink(struct _reent *r, const char *path);
int esp_vfs_rename(struct _reent *r, const char *src, const char *dst);
/**@}*/
#ifdef __cplusplus
} // extern "C"
#endif
#endif //__ESP_VFS_H__