About RamFS

RamFS is a memory based filesystem designed for embedded use. It can be easily used with a CMake project — including ESP-IDF.

Getting started with ESP-IDF

To use this component with ESP-IDF, within your projects directory run

idf.py add-dependency jkent/ramfs

Usage

Two interfaces are available: the bare API or when using IDF there is the VFS interface which builds on top of the bare API. You should use the VFS interface in IDF projects, as it uses the portable and familiar posix and stdio C functions with it. There is nothing preventing you from mix and matching both at the same time, however.

Shared initialization

Initialization is as simple as calling ramfs_init function and checking its return variable:

ramfs_fs_t *fs = ramfs_init();
assert(fs != NULL);

When done, and all file handles are closed, you can call ramfs_deinit:

ramfs_deinit(fs);

VFS interface

The VFS interface adds another step to the initialization: you define a ramfs_vfs_conf_t structure:

• base_path - path to mount the ramfs
• fs - a ramfs_fs_t instance
• max_files - max number of files that can be open at a time

ramfs_vfs_conf_t ramfs_vfs_conf = {
    .base_path = "/ramfs",
    .fs = fs,
    .max_files = 5,
};
ramfs_vfs_register(&ramfs_vfs_conf);

Bare API

Filesystem functions:

• ramfs_fs_t *ramfs_init(void)
• void ramfs_deinit(ramfs_fs_t *fs)

Object functions:

• const ramfs_entry_t *ramfs_get_parent(ramfs_fs_t *fs, const char *path)
• const ramfs_entry_t *ramfs_get_entry(ramfs_fs_t *fs, const char *path)
• const char *ramfs_get_name(const ramfs_entry_t *entry)
• const char *ramfs_get_path(const ramfs_entry_t *entry)
• int ramfs_is_dir(const ramfs_entry_t *entry)
• int ramfs_is_file(const ramfs_entry_t *entry)
• void ramfs_stat(const ramfs_fs_t *fs, const ramfs_entry_t *entry, ramfs_stat_t *st)
• void ramfs_create(ramfs_fs_t *fs, const char *path, int flags)
• void ramfs_truncate(ramfs_fs_t *fs, const ramfs_entry_t *entry, size_T size)
• ramfs_fh_t *ramfs_open(ramfs_fs_t *fs, const ramfs_entry_t *entry, unsigned int flags)
• void ramfs_close(ramfs_fh_t *fh)
• size_t ramfs_read(ramfs_fh_t *fh, void *buf, size_t len)
• size_t ramfs_write(ramfs_fh_t *fh, void *buf, size_t len)
• ssize_t ramfs_seek(ramfs_fh_t *fh, long offset, int mode)
• size_t ramfs_tell(ramfs_fh_t *fh)
• size_t ramfs_access(ramfs_fh_t *fh, void **buf)
• int ramfs_unlink(ramfs_entry_t *entry)
• int ramfs_rename(ramfs_fs_t *fs, const char *src, const char *dst)

Directory Functions:

• ramfs_dh_t *ramfs_opendir(ramfs_fs_t *fs, const ramfs_entry_t *entry)
• void ramfs_closedir(ramfs_dh_t *dh)
• const ramfs_entry_t *ramfs_readdir(ramfs_dh_t *dh)
• void ramfs_seekdir(ramfs_dh_t *dh, long loc)
• long ramfs_telldir(ramfs_dh_t *dh)
• ramfs_entry_t *ramfs_mkdir(ramfs_fs_t *fs, const char *name)
• int ramfs_rmdir(ramfs_entry_t *entry)
• void ramfs_rmtree(ramfs_entry_t *entry)