Filesystem.

Filesystem interface. More...

Collaboration diagram for Filesystem.:

Detailed Description

Filesystem interface.

The filesystem interface represents a filesystem type, e.g. fat32, tmpfs, devfs, etc. Each filesystem is exposed in a directory within the fs sysfs directory named after the filesystem.

The directory itself can be used to mount instances of that filesystem type.

Within each filesystem directory are readable files representing each mounted instance of that filesystem type, named after the superblock ID, containing the following information:

id: %llu
block_size: %llu
max_file_size: %llu

Where the id is the superblock ID, block_size is the block size of the superblock, and max_file_size is the maximum size of a file on this superblock.

See also

System Filesystem

Data Structures
struct	filesystem_t
	Filesystem structure, represents a filesystem type, e.g. fat32, tmpfs, devfs, etc. More...

Macros
#define	OPTIONS_FOR_EACH(options, key, value)
	Helper macro for iterating over options passed to a filesystem mount operation.

Functions
void	filesystem_expose (void)
	Exposes the sysfs fs directory.
uint64_t	filesystem_register (filesystem_t *fs)
	Registers a filesystem.
void	filesystem_unregister (filesystem_t *fs)
	Unregisters a filesystem.
filesystem_t *	filesystem_get_by_name (const char *name)
	Gets a filesystem by name.
filesystem_t *	filesystem_get_by_path (const char *path, process_t *process)
	Gets a filesystem by path.
bool	options_next (const char **iter, char *buffer, size_t size, char **key, char **value)
	Helper function for iterating over options passed to a filesystem mount operation.

Macro Definition Documentation

OPTIONS_FOR_EACH

#define OPTIONS_FOR_EACH	(		options,
			key,
			value
	)

Value:

    for (struct { \
             const char* iter; \
             char buf[256]; \
         } _state = {(options), {0}}; \
        options_next(&_state.iter, _state.buf, sizeof(_state.buf), &(key), &(value));)

Helper macro for iterating over options passed to a filesystem mount operation.

Each helper option is specified as key=value pairs, with multiple options separated by commas.

Parameters

options	The options string.
key	The key variable.
value	The value variable.

Definition at line 140 of file filesystem.h.

Function Documentation

filesystem_expose()

void filesystem_expose

(

void

)

Exposes the sysfs fs directory.

s

Must be called before filesystem_get_by_path() can be used.

Definition at line 215 of file filesystem.c.

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filesystem_register()

uint64_t filesystem_register

(

filesystem_t *

fs

)

Registers a filesystem.

Parameters

fs	The filesystem to register.

Returns

On success, 0. On failure, ERR and errno is set to:

• EINVAL: Invalid parameters.
• Other values from map_insert().

Definition at line 233 of file filesystem.c.

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filesystem_unregister()

void filesystem_unregister

(

filesystem_t *

fs

)

Unregisters a filesystem.

Parameters

fs	The filesystem to unregister, or NULL for no-op.

Definition at line 259 of file filesystem.c.

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filesystem_get_by_name()

filesystem_t * filesystem_get_by_name

(

const char *

name

)

Gets a filesystem by name.

Parameters

name	The name of the filesystem.

Returns

On success, the filesystem. On failure, returns NULL.

Definition at line 276 of file filesystem.c.

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filesystem_get_by_path()

filesystem_t * filesystem_get_by_path	(	const char *	path,
		process_t *	process
	)

Gets a filesystem by path.

The path should point to a directory in the fs sysfs directory.

Parameters

path	The path to check.
process	The process whose namespace to use.

Returns

On success, the filesystem. On failure, returns NULL and errno is set to:

• ENOENT: The path does not exist.
• ENOMEM: Out of memory.
• EINVAL: The path is not a directory in the fs sysfs directory.

Definition at line 284 of file filesystem.c.

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options_next()

bool options_next	(	const char **	iter,
		char *	buffer,
		size_t	size,
		char **	key,
		char **	value
	)

Helper function for iterating over options passed to a filesystem mount operation.

Each helper option is specified as key=value pairs, with multiple options separated by commas.

Parameters

iter	Pointer to the current iterator position. Updated on each call.
buffer	Buffer to store the current option.
size	Size of the buffer.
key	Pointer to store the key of the current option.
value	Pointer to store the value of the current option.

Returns

1 if an option was found, 0 if no more options are available.

Definition at line 327 of file filesystem.c.

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