IMFS Generic Nodes

Generic nodes are an alternative to standard drivers in RTEMS. More...

Data Structures
struct	IMFS_node_control
	IMFS node control. More...
struct	IMFS_mknod_control

Macros
#define	IMFS_GENERIC_INITIALIZER(handlers, init, destroy)   IMFS_NODE_CONTROL_INITIALIZER( handlers, init, destroy )
#define	IMFS_GENERIC_CONTROL_INITIALIZER(handlers, init, destroy)   IMFS_NODE_CONTROL_INITIALIZER( handlers, init, destroy )
	Initializer for a generic node control. More...
#define	IMFS_GENERIC_NODE_INITIALIZER(node_control, name, namelen, mode)   { IMFS_NODE_INITIALIZER( node_control, name, namelen, mode ), NULL }
	Initializer for a generic node. More...

Typedefs
typedef IMFS_jnode_t *(*	IMFS_node_control_initialize) (IMFS_jnode_t *node, void *arg)
	Initializes an IMFS node. More...
typedef IMFS_jnode_t *(*	IMFS_node_control_remove) (IMFS_jnode_t *node)
	Prepares the removal of an IMFS node from its parent directory. More...
typedef void(*	IMFS_node_control_destroy) (IMFS_jnode_t *node)
	Destroys an IMFS node. More...

Functions
IMFS_jnode_t *	IMFS_node_initialize_default (IMFS_jnode_t *node, void *arg)
	Returns the node and does nothing else. More...
IMFS_jnode_t *	IMFS_node_initialize_directory (IMFS_jnode_t *node, void *arg)
IMFS_jnode_t *	IMFS_node_initialize_generic (IMFS_jnode_t *node, void *arg)
	Returns the node and sets the generic node context. More...
IMFS_jnode_t *	IMFS_node_remove_default (IMFS_jnode_t *node)
	Returns the node and does nothing else. More...
IMFS_jnode_t *	IMFS_node_remove_directory (IMFS_jnode_t *node)
void	IMFS_node_destroy_default (IMFS_jnode_t *node)
	Frees the node. More...
void	IMFS_do_nothing_destroy (IMFS_jnode_t *node)
	Does nothing. More...
int	IMFS_make_generic_node (const char *path, mode_t mode, const IMFS_node_control *node_control, void *context)
	Makes a generic IMFS node. More...

Detailed Description

Generic nodes are an alternative to standard drivers in RTEMS.

The handlers of a generic node are called with less overhead compared to the standard driver operations. The usage of file system node handlers enable more features like support for fsync() and fdatasync(). The generic nodes use the reference counting of the IMFS. This provides automatic node destruction when the last reference vanishes.

Macro Definition Documentation

IMFS_GENERIC_CONTROL_INITIALIZER

#define IMFS_GENERIC_CONTROL_INITIALIZER	(		handlers,
			init,
			destroy
	)		IMFS_NODE_CONTROL_INITIALIZER( handlers, init, destroy )

Initializer for a generic node control.

Parameters

handlers	The file system node handlers.
init	The node initialization method.
destroy	The node destruction method.

IMFS_GENERIC_NODE_INITIALIZER

#define IMFS_GENERIC_NODE_INITIALIZER	(		node_control,
			name,
			namelen,
			mode
	)		{ IMFS_NODE_INITIALIZER( node_control, name, namelen, mode ), NULL }

Initializer for a generic node.

Initialize the node control with IMFS_GENERIC_CONTROL_INITIALIZER().

Parameters

node_control	The node control of the IMFS generic node.
name	The name of the IMFS generic node.
namelen	The length of the name of the IMFS generic node.
mode	The mode of the IMFS generic node.

Typedef Documentation

IMFS_node_control_destroy

typedef void(* IMFS_node_control_destroy) (IMFS_jnode_t *node)

Destroys an IMFS node.

Parameters

[in]

node

The IMFS node.

See also

IMFS_node_control and IMFS_node_destroy_default().

IMFS_node_control_initialize

typedef IMFS_jnode_t*(* IMFS_node_control_initialize) (IMFS_jnode_t *node, void *arg)

Initializes an IMFS node.

Parameters

[in]	node	The IMFS node.
[in]	arg	The user provided argument pointer. It may contain node specific initialization information.

Return values

node	Successful operation.
NULL	An error occurred. The errno indicates the error. This will abort the make operation.

See also

IMFS_node_control, IMFS_node_initialize_default(), and IMFS_node_initialize_generic().

IMFS_node_control_remove

typedef IMFS_jnode_t*(* IMFS_node_control_remove) (IMFS_jnode_t *node)

Prepares the removal of an IMFS node from its parent directory.

Parameters

[in]

node

The IMFS node.

Return values

node	Successful operation.
NULL	An error occurred. The errno indicates the error. This will abort the removal operation.

See also

IMFS_node_control and IMFS_node_remove_default().

Function Documentation

IMFS_do_nothing_destroy()

void IMFS_do_nothing_destroy

(

IMFS_jnode_t *

node

)

Does nothing.

Parameters

node	The IMFS node.

See also

IMFS_node_control.

IMFS_make_generic_node()

int IMFS_make_generic_node	(	const char *	path,
		mode_t	mode,
		const IMFS_node_control *	node_control,
		void *	context
	)

Makes a generic IMFS node.

Parameters

[in]	path	The path to the new generic IMFS node.
[in]	mode	The node mode.
[in]	node_control	The node control.
[in]	context	The node control handler context.

Return values

0	Successful operation.
-1	An error occurred. The errno indicates the error.

#include <sys/stat.h>
#include <assert.h>
#include <fcntl.h>

#include <rtems/imfs.h>

static const rtems_filesystem_file_handlers_r some_node_handlers = {
  ...
};

static IMFS_jnode_t *some_node_init(IMFS_jnode_t *node, void *arg)
{
  void *context;

  node = IMFS_node_initialize_generic(node, arg);
  context = IMFS_generic_get_context_by_node(node);

  return node;
}

static void some_node_destroy(IMFS_jnode_t *node)
{
  void *context = IMFS_generic_get_context_by_node(node);

  IMFS_node_destroy_default(node);
}

static const IMFS_node_control
some_node_control = IMFS_GENERIC_CONTROL_INITIALIZER(
  &some_node_handlers,
  some_node_init,
  some_node_destroy
);

void example(void *some_node_context)
{
  int rv;

  rv = IMFS_make_generic_node(
    "/path/to/some/generic/node",
    S_IFCHR | S_IRWXU | S_IRWXG | S_IRWXO,
    &some_node_control,
    some_node_context
  );
  assert(rv == 0);
}

IMFS_node_destroy_default()

void IMFS_node_destroy_default

(

IMFS_jnode_t *

node

)

Frees the node.

Parameters

[in]

node

The IMFS node.

See also

IMFS_node_control.

IMFS_node_initialize_default()

IMFS_jnode_t* IMFS_node_initialize_default	(	IMFS_jnode_t *	node,
		void *	arg
	)

Returns the node and does nothing else.

Parameters

[in]	node	The IMFS node.
[in]	arg	The user provided argument pointer. It is not used.

Return values

node	Returns always the node passed as parameter.

See also

IMFS_node_control.

IMFS_node_initialize_generic()

IMFS_jnode_t* IMFS_node_initialize_generic	(	IMFS_jnode_t *	node,
		void *	arg
	)

Returns the node and sets the generic node context.

Parameters

[in]	node	The IMFS node.
[in]	arg	The user provided argument pointer. It must contain the generic context.

Return values

node	Returns always the node passed as parameter.

See also

IMFS_node_control.

IMFS_node_remove_default()

IMFS_jnode_t* IMFS_node_remove_default

(

IMFS_jnode_t *

node

)

Returns the node and does nothing else.

Parameters

[in]

node

The IMFS node.

Return values

node	Returns always the node passed as parameter.

See also

IMFS_node_control.