Input/Output stream for IPC [un]marshalling. More...

#include <ipc_stream>

Inheritance diagram for L4::Ipc::Iostream:

Collaboration diagram for L4::Ipc::Iostream:

Public Member Functions
	Iostream (l4_utcb_t *utcb)
	Create an IPC IO stream with a single message buffer.

void	reset ()
	Reset the stream to its initial state.

IPC operations.
l4_msgtag_t	call (l4_cap_idx_t dst, l4_timeout_t timeout, long proto=0)
	Do an IPC call using the message in the output stream and receive the reply in the input stream.

l4_msgtag_t	reply_and_wait (l4_umword_t *src_dst, long proto=0)
	Do an IPC reply and wait.

l4_msgtag_t	reply_and_wait (l4_umword_t *src_dst, l4_timeout_t timeout, long proto=0)
	Do an IPC reply and wait.

Get/Put functions.
These functions are basically used to implement the insertion operators (<<) and should not be called directly.
template<typename T >
unsigned long	get (T *buf, unsigned long elems)
	Copy out an array of type `T` with `size` elements.

template<typename T >
unsigned long	get (Msg_ptr< T > const &buf, unsigned long elems=1)
	Read one size elements of type T from the stream and return a pointer.

template<typename T >
bool	get (T &v)
	Extract a single element of type T from the stream.

template<typename T >
bool	put (T *buf, unsigned long size)
	Put an array with `size` elements of type `T` into the stream.

template<typename T >
bool	put (T const &v)
	Insert an element of type `T` into the stream.

Public Member Functions inherited from L4::Ipc::Istream
	Istream (l4_utcb_t *utcb)
	Create an input stream for the given message buffer.

void	reset ()
	Reset the stream to empty, and ready for receive()/wait().

template<typename T >
bool	has_more (unsigned long count=1)
	Check whether a value of type T can be obtained from the stream.

l4_utcb_t *	utcb () const
	Return utcb pointer.

template<typename T >
unsigned long	get (T *buf, unsigned long elems)
	Copy out an array of type `T` with `size` elements.

template<typename T >
void	skip (unsigned long elems)
	Skip size elements of type T in the stream.

template<typename T >
unsigned long	get (Msg_ptr< T > const &buf, unsigned long elems=1)
	Read one size elements of type T from the stream and return a pointer.

template<typename T >
bool	get (T &v)
	Extract a single element of type T from the stream.

l4_msgtag_t	tag () const
	Get the message tag of a received IPC.

l4_msgtag_t &	tag ()
	Get the message tag of a received IPC.

l4_msgtag_t	wait (l4_umword_t *src)
	Wait for an incoming message from any sender.

l4_msgtag_t	wait (l4_umword_t *src, l4_timeout_t timeout)
	Wait for an incoming message from any sender.

l4_msgtag_t	receive (l4_cap_idx_t src)
	Wait for a message from the specified sender.

Public Member Functions inherited from L4::Ipc::Ostream
	Ostream (l4_utcb_t *utcb)
	Create an IPC output stream using the given message buffer `utcb`.

void	reset ()
	Reset the stream to empty, same state as a newly created stream.

l4_utcb_t *	utcb () const
	Return utcb pointer.

template<typename T >
bool	put (T *buf, unsigned long size)
	Put an array with `size` elements of type `T` into the stream.

template<typename T >
bool	put (T const &v)
	Insert an element of type `T` into the stream.

l4_msgtag_t	tag () const
	Extract the L4 message tag from the stream.

l4_msgtag_t &	tag ()
	Extract a reference to the L4 message tag from the stream.

l4_msgtag_t	send (l4_cap_idx_t dst, long proto=0, unsigned flags=0)
	Send the message via IPC to the given receiver.

Detailed Description

Input/Output stream for IPC [un]marshalling.

The Ipc::Iostream is part of the AW Env IPC framework as well as Ipc::Istream and Ipc::Ostream. In particular an Ipc::Iostream is a combination of an Ipc::Istream and an Ipc::Ostream. It can use either a single message buffer for receiving and sending messages or a pair of a receive and a send buffer. The stream also supports combined IPC operations such as call() and reply_and_wait(), which can be used to implement RPC functionality.

Examples: examples/libs/l4re/c++/shared_ds/ds_srv.cc, examples/libs/l4re/streammap/client.cc, and examples/libs/l4re/streammap/server.cc.

Definition at line 800 of file ipc_stream.

Constructor & Destructor Documentation

◆ Iostream()

L4::Ipc::Iostream::Iostream ( l4_utcb_t * utcb )

inlineexplicit

Create an IPC IO stream with a single message buffer.

Parameters

utcb	The message buffer used as backing store.

The created IO stream uses the same message buffer for sending and receiving IPC messages.

Definition at line 812 of file ipc_stream.

Member Function Documentation

◆ call()

l4_msgtag_t L4::Ipc::Iostream::call	(	l4_cap_idx_t	dst,
		l4_timeout_t	timeout,
		long	proto = `0`
	)

inline

Do an IPC call using the message in the output stream and receive the reply in the input stream.

Parameters

dst	The destination to call.
timeout	The IPC timeout for the call.
proto	The protocol value to use in the message tag.

Returns: The result tag of the IPC operation.

This is a combined IPC operation consisting of a send and a receive to/from the given destination dst.

A call is usually used by clients for RPCs to a server.

Examples: examples/libs/l4re/streammap/client.cc.

Definition at line 971 of file ipc_stream.

References l4_ipc_call(), and L4::Ipc::Istream::tag().

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◆ get() [1/3]

template<typename T >

unsigned long L4::Ipc::Istream::get	(	Msg_ptr< T > const &	buf,
		unsigned long	elems = `1`
	)

inline

Read one size elements of type T from the stream and return a pointer.

Parameters

buf	A Msg_ptr that is actually set to point to the element in the stream.
elems	Number of elements to extract (default is 1).

Returns: The number of elements extracted.

In contrast to a normal get, this version does actually not copy the data but returns a pointer to the data.

See Istream::operator>>()

Definition at line 450 of file ipc_stream.

◆ get() [2/3]

template<typename T >

bool L4::Ipc::Istream::get ( T & v )

inline

Extract a single element of type T from the stream.

Parameters

[out] v The element.

Return values

true	An element was successfully extracted.
false	An element could not be extracted.

See Istream::operator>>()

Definition at line 475 of file ipc_stream.

◆ get() [3/3]

template<typename T >

unsigned long L4::Ipc::Istream::get	(	T *	buf,
		unsigned long	elems
	)

inline

Copy out an array of type T with size elements.

Parameters

buf	Pointer to a buffer for size elements of type T.
elems	Number of elements of type T to copy out.

Returns: The number of elements copied out.

See Istream::operator>>()

Definition at line 405 of file ipc_stream.

◆ put() [1/2]

template<typename T >

bool L4::Ipc::Ostream::put	(	T *	buf,
		unsigned long	size
	)

inline

Put an array with size elements of type T into the stream.

Parameters

buf	A pointer to the array to insert into the buffer.
size	The number of elements in the array.

Definition at line 669 of file ipc_stream.

◆ put() [2/2]

template<typename T >

bool L4::Ipc::Ostream::put ( T const & v )

inline

Insert an element of type T into the stream.

Parameters

v	The element to insert.

Definition at line 687 of file ipc_stream.

◆ reply_and_wait() [1/2]

l4_msgtag_t L4::Ipc::Iostream::reply_and_wait	(	l4_umword_t *	src_dst,
		l4_timeout_t	timeout,
		long	proto = `0`
	)

inline

Do an IPC reply and wait.

Parameters

[in,out]	src_dst	Input: the destination for the send operation. Output: the source of the received message.
	timeout	Timeout used for IPC.
	proto	Protocol to use.

Returns: The result tag of the IPC operation.

This is a combined IPC operation consisting of a send operation and an open wait for any message.

A reply and wait is usually used by servers that reply to a client and wait for the next request by any other client.

Definition at line 986 of file ipc_stream.

References l4_ipc_reply_and_wait(), and L4::Ipc::Istream::tag().

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◆ reply_and_wait() [2/2]

l4_msgtag_t L4::Ipc::Iostream::reply_and_wait	(	l4_umword_t *	src_dst,
		long	proto = `0`
	)

inline

Do an IPC reply and wait.

Parameters

[in,out]	src_dst	Input: the destination for the send operation. Output: the source of the received message.
	proto	Protocol to use.

Returns: The result tag of the IPC operation.

This is a combined IPC operation consisting of a send operation and an open wait for any message.

A reply and wait is usually used by servers that reply to a client and wait for the next request by any other client.

Definition at line 885 of file ipc_stream.

References L4_IPC_SEND_TIMEOUT_0, and reply_and_wait().

Referenced by reply_and_wait().

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◆ reset()

void L4::Ipc::Iostream::reset ( )

inline

Reset the stream to its initial state.

Input as well as the output stream are reset.

Definition at line 826 of file ipc_stream.

References L4::Ipc::Istream::reset(), and L4::Ipc::Ostream::reset().

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

l4/cxx/ipc_stream

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ Iostream()

Member Function Documentation

◆ call()

◆ get() [1/3]

◆ get() [2/3]

◆ get() [3/3]

◆ put() [1/2]

◆ put() [2/2]

◆ reply_and_wait() [1/2]

◆ reply_and_wait() [2/2]

◆ reset()