filesystem_t Struct Reference

Filesystem hook structure. More...

#include <system.h>

Data Fields
void *(*	open )(char *name, int flags)
	Function to call when performing an open command.
int(*	fstat )(void *file, struct stat *st)
	Function to call when performing a fstat command.
int(*	stat )(char *name, struct stat *st)
	Function to call when performing a stat command.
int(*	lseek )(void *file, int ptr, int dir)
	Function to call when performing an lseek command.
int(*	read )(void *file, uint8_t *ptr, int len)
	Function to call when performing a read operation.
int(*	write )(void *file, uint8_t *ptr, int len)
	Function to call when performing a write operation.
int(*	close )(void *file)
	Function to call when performing a close operation.
int(*	unlink )(char *name)
	Function to call when performing an unlink operation.
int(*	findfirst )(char *path, dir_t *dir)
	Function to call when performing a findfirst operation.
int(*	findnext2 )(const char *path, dir_t *dir)
	Function to call when performing a findnext operation.
int(*	ftruncate )(void *file, int length)
	Truncate a file to a specified length.
int(*	mkdir )(char *path, mode_t mode)
	Create a directory.
int(*	ioctl )(void *file, unsigned long cmd, void *argp)
	Perform IO Control Request.

Detailed Description

Filesystem hook structure.

Filesystems that do not support one of more of the following methods should provide null pointers instead of empty functions. The newlib hooks will set errno to ENOSYS and return a proper error to userspace.

All filesystems functions must set errno in case of error, to report the proper error to userspace.

Field Documentation

open

void *(* filesystem_t::open) (char *name, int flags)

Function to call when performing an open command.

Parameters

[in]	name	Full path of the file to be opened, relative to the root of the filesystem.
[in]	flags	Open flags, such as binary, append, etc. Follows POSIX flags.

Returns

A pointer to an arbitrary file handle assigned by the filesystem code or NULL on error (and errno is set).

fstat

int(* filesystem_t::fstat) (void *file, struct stat *st)

Function to call when performing a fstat command.

Parameters

[in]	file	Arbitrary file handle returned by filesystem_t::open
[out]	st	Stat structure to populate with file statistics

Returns

0 on success or a negative value on error (and errno is set).

stat

int(* filesystem_t::stat) (char *name, struct stat *st)

Function to call when performing a stat command.

Parameters

[in]	file	Full path of the file to be examined, relative to the root of the filesystem.
[out]	st	Stat structure to populate with file statistics

Returns

0 on success or a negative value on error (and errno is set).

lseek

int(* filesystem_t::lseek) (void *file, int ptr, int dir)

Function to call when performing an lseek command.

Parameters

[in]	file	Arbitrary file handle returned by filesystem_t::open
[in]	ptr	An offset from dir to seek.
[in]	dir	A direction to see, either SEEK_SET, SEEK_CUR or SEEK_END

Returns

The absolute offset in bytes after the seek or a negative value on failure (and errno is set).

read

int(* filesystem_t::read) (void *file, uint8_t *ptr, int len)

Function to call when performing a read operation.

Parameters

[in]	file	Arbitrary file handle returned by filesystem_t::open
[out]	ptr	Buffer to place data read into
[in]	len	Length of data that should be read into ptr

Returns

The actual number of bytes read into ptr or a negative value on failure (and errno is set).

write

int(* filesystem_t::write) (void *file, uint8_t *ptr, int len)

Function to call when performing a write operation.

Parameters

[in]	file	Arbitrary file handle returned by filesystem_t::open
[out]	ptr	Buffer to grab the data to be written
[in]	len	Length of data that should be written out of ptr

Returns

The actual number of bytes written or a negative value on failure (and errno is set).

close

int(* filesystem_t::close) (void *file)

Function to call when performing a close operation.

Parameters

[in]

file

Arbitrary file handle returned by filesystem_t::open

Returns

0 on success or a negative value on failure (and errno is set).

unlink

int(* filesystem_t::unlink) (char *name)

Function to call when performing an unlink operation.

Parameters

[in]

name

Full path of the file to be opened, relative to the root of the filesystem.

Returns

0 on success or a negative value on failure (and errno is set).

findfirst

int(* filesystem_t::findfirst) (char *path, dir_t *dir)

Function to call when performing a findfirst operation.

Parameters

[in]	path	Full path of the directory to list files from, relative to the root of the filesystem. It always begins with a slash.
[out]	dir	Directory structure to place information on the first file in the directory.

Returns

0 on successful lookup, -1 if the directory existed and is empty, or a different negative value on error (in which case, errno will be set).

findnext2

int(* filesystem_t::findnext2) (const char *path, dir_t *dir)

Function to call when performing a findnext operation.

Parameters

[in]	path	Full path of the directory to list files from, relative to the root of the filesystem. It always begins with a slash.
[out]	dir	Directory structure to place information on the next file in the directory.

Returns

0 on successful lookup, -1 if the directory existed and is empty, or a different negative value on error (in which case, errno will be set).

ftruncate

int(* filesystem_t::ftruncate) (void *file, int length)

Truncate a file to a specified length.

Parameters

file	Arbitrary file handle returned by filesystem_t::open
length	New length of the file

Returns

0 on success or a negative value on failure (and errno is set)

mkdir

int(* filesystem_t::mkdir) (char *path, mode_t mode)

Create a directory.

Parameters

[in]	path	Full path of the directory to create, relative to the root of the filesystem.
[in]	mode	Directory permissions

Returns

0 on success or a negative value on failure (errno must be set)

ioctl

int(* filesystem_t::ioctl) (void *file, unsigned long cmd, void *argp)

Perform IO Control Request.

Parameters

[in]	file	File handle
[in]	cmd	Request ioctl command code
[in]	argp	Pointer to a request-specific data structure

Returns

0 on success or a negative value on failure (errno must be set)

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The documentation for this struct was generated from the following file:

• system.h