Contiki processes

Collaboration diagram for Contiki processes:

Files
file	process.h

Macros
#define	PROCESS_EVENT_NET_FLOW_ON   0x8a

Return values
#define	PROCESS_ERR_OK   0
	Return value indicating that an operation was successful. More...
#define	PROCESS_ERR_FULL   1
	Return value indicating that the event queue was full. More...

Process protothread functions
#define	PROCESS_BEGIN()
#define	PROCESS_END()
#define	PROCESS_WAIT_EVENT()
#define	PROCESS_WAIT_EVENT_UNTIL(c)
#define	PROCESS_YIELD()
#define	PROCESS_YIELD_UNTIL(c)
#define	PROCESS_WAIT_UNTIL(c)
#define	PROCESS_WAIT_WHILE(c)    PT_WAIT_WHILE(process_pt, c)
#define	PROCESS_EXIT()
#define	PROCESS_PT_SPAWN(pt, thread)
#define	PROCESS_PAUSE()

Poll and exit handlers
#define	PROCESS_POLLHANDLER(handler)
#define	PROCESS_EXITHANDLER(handler)

Process declaration and definition
#define	PROCESS_THREAD(name, ev, data)
#define	PROCESS_NAME(name)
#define	PROCESS(name, strname)

Functions called from application programs
CCIF struct process *	process_current
CCIF void	process_start (struct process *p, const char *arg)
CCIF int	process_post (struct process *p, process_event_t ev, void *data)
CCIF void	process_post_synch (struct process *p, process_event_t ev, void *data)
CCIF int	process_abort_event (struct process *p, process_event_t ev, void **pdata)
CCIF void	process_exit (struct process *p)
	Cause a process to exit. More...
CCIF process_event_t	process_alloc_event (void)
	Allocate a global event number. More...
#define	process_abort_all_events(p, ev)   do { } while (process_abort_event(p, ev, NULL))
#define	PROCESS_CURRENT()
#define	PROCESS_CONTEXT_BEGIN(p)
#define	PROCESS_CONTEXT_END(p)   process_current = tmp_current; }

Functions called from device drivers
CCIF void	process_poll (struct process *p)

Functions called by the system and boot-up code
void	process_init (void)
	Initialize the process module. More...
int	process_run (void)
CCIF int	process_is_running (struct process *p)
int	process_nevents (void)

Detailed Description

A process in Contiki consists of a single protothread.

Macro Definition Documentation

#define PROCESS_ERR_OK   0

Return value indicating that an operation was successful.

This value is returned to indicate that an operation was successful.

Definition at line 74 of file process.h.

Referenced by process_post().

#define PROCESS_ERR_FULL   1

Return value indicating that the event queue was full.

This value is returned from process_post() to indicate that the event queue was full and that an event could not be posted.

Definition at line 82 of file process.h.

Referenced by process_post().

#define PROCESS_EVENT_NET_FLOW_ON   0x8a

Flow on event

The event is sent to usbnet process when a new buffer becomes available in the managed pool and UIP code can continue data sending

#define PROCESS_BEGIN

(

)

Define the beginning of a process.

This macro defines the beginning of a process, and must always appear in a PROCESS_THREAD() definition. The PROCESS_END() macro must come at the end of the process.

Definition at line 129 of file process.h.

Referenced by simple_udp_deregister(), and tcpip_input().

#define PROCESS_END

(

)

Define the end of a process.

This macro defines the end of a process. It must appear in a PROCESS_THREAD() definition and must always be included. The process exits when the PROCESS_END() macro is reached.

Definition at line 140 of file process.h.

Referenced by simple_udp_deregister(), and tcpip_input().

#define PROCESS_WAIT_EVENT

(

)

Wait for an event to be posted to the process.

This macro blocks the currently running process until the process receives an event.

Definition at line 150 of file process.h.

Referenced by simple_udp_deregister().

#define PROCESS_WAIT_EVENT_UNTIL

(

c

)

Wait for an event to be posted to the process, with an extra condition.

This macro is similar to PROCESS_WAIT_EVENT() in that it blocks the currently running process until the process receives an event. But PROCESS_WAIT_EVENT_UNTIL() takes an extra condition which must be true for the process to continue.

Parameters

c	The condition that must be true for the process to continue.

See also

PT_WAIT_UNTIL()

Definition at line 166 of file process.h.

#define PROCESS_YIELD

(

)

Yield the currently running process.

Definition at line 173 of file process.h.

Referenced by tcpip_input().

#define PROCESS_YIELD_UNTIL

(

c

)

Yield the currently running process until a condition occurs.

This macro is different from PROCESS_WAIT_UNTIL() in that PROCESS_YIELD_UNTIL() is guaranteed to always yield at least once. This ensures that the process does not end up in an infinite loop and monopolizing the CPU.

Parameters

c	The condition to wait for.

Definition at line 187 of file process.h.

#define PROCESS_WAIT_UNTIL

(

c

)

Wait for a condition to occur.

This macro does not guarantee that the process yields, and should therefore be used with care. In most cases, PROCESS_WAIT_EVENT(), PROCESS_WAIT_EVENT_UNTIL(), PROCESS_YIELD() or PROCESS_YIELD_UNTIL() should be used instead.

Parameters

c	The condition to wait for.

Definition at line 201 of file process.h.

#define PROCESS_EXIT

(

)

Exit the currently running process.

Definition at line 209 of file process.h.

#define PROCESS_PT_SPAWN	(		pt,
			thread
	)

Spawn a protothread from the process.

Parameters

pt	The protothread state (struct pt) for the new protothread
thread	The call to the protothread function.

See also

PT_SPAWN()

Definition at line 220 of file process.h.

#define PROCESS_PAUSE

(

)

Yield the process for a short while.

This macro yields the currently running process for a short while, thus letting other processes run before the process continues.

Definition at line 230 of file process.h.

#define PROCESS_POLLHANDLER

(

handler

)

Specify an action when a process is polled.

Note

This declaration must come immediately before the PROCESS_BEGIN() macro.

Parameters

handler

The action to be performed.

Definition at line 251 of file process.h.

#define PROCESS_EXITHANDLER

(

handler

)

Specify an action when a process exits.

Note

This declaration must come immediately before the PROCESS_BEGIN() macro.

Parameters

handler

The action to be performed.

Definition at line 263 of file process.h.

#define PROCESS_THREAD	(		name,
			ev,
			data
	)

Define the body of a process.

This macro is used to define the body (protothread) of a process. The process is called whenever an event occurs in the system, A process always start with the PROCESS_BEGIN() macro and end with the PROCESS_END() macro.

Definition at line 282 of file process.h.

Referenced by simple_udp_deregister(), and tcpip_input().

#define PROCESS_NAME

(

name

)

Declare the name of a process.

This macro is typically used in header files to declare the name of a process that is implemented in the C file.

Definition at line 295 of file process.h.

#define PROCESS	(		name,
			strname
	)

Declare a process.

This macro declares a process. The process has two names: the variable of the process structure, which is used by the C program, and a human readable string name, which is used when debugging. A configuration option allows removal of the readable name to save RAM.

Parameters

name	The variable name of the process structure.
strname	The string representation of the process' name.

Definition at line 316 of file process.h.

Referenced by tcpip_output().

#define process_abort_all_events	(		p,
			ev
	)		do { } while (process_abort_event(p, ev, NULL))

Remove all events of the given type from the process queue.

Parameters

p	A pointer to the process' process structure.
ev	The event to remove.

Definition at line 412 of file process.h.

#define PROCESS_CURRENT

(

)

Get a pointer to the currently running process.

This macro get a pointer to the currently running process. Typically, this macro is used to post an event to the current process with process_post().

Definition at line 437 of file process.h.

Referenced by ctimer_set(), etimer_request_poll(), process_exit(), process_post(), tcpip_input(), and tcpip_output().

#define PROCESS_CONTEXT_BEGIN

(

p

)

Value:

{\
struct process *tmp_current = PROCESS_CURRENT();\
process_current = p

Switch context to another process

This function switch context to the specified process and executes the code as if run by that process. Typical use of this function is to switch context in services, called by other processes. Each PROCESS_CONTEXT_BEGIN() must be followed by the PROCESS_CONTEXT_END() macro to end the context switch.

Example:

PROCESS_CONTEXT_BEGIN(&test_process);
etimer_set(&timer, CLOCK_SECOND);
PROCESS_CONTEXT_END(&test_process);

Parameters

p	The process to use as context

See also

PROCESS_CONTEXT_END()

PROCESS_CURRENT()

Definition at line 461 of file process.h.

Referenced by ctimer_reset(), ctimer_restart(), ctimer_set(), simple_udp_deregister(), and simple_udp_register().

#define PROCESS_CONTEXT_END

(

p

)

process_current = tmp_current; }

End a context switch

This function ends a context switch and changes back to the previous process.

Parameters

p	The process used in the context switch

See also

PROCESS_CONTEXT_START()

Definition at line 475 of file process.h.

Referenced by ctimer_reset(), ctimer_restart(), ctimer_set(), simple_udp_deregister(), and simple_udp_register().

Function Documentation

CCIF void process_start	(	struct process *	p,
		const char *	arg
	)

Start a process.

Parameters

p	A pointer to a process structure.
arg	An argument pointer that can be passed to the new process

Definition at line 100 of file process.c.

References data, process_is_running(), process_post_synch(), and PT_INIT.

Referenced by ctimer_init().

CCIF int process_post	(	struct process *	p,
		process_event_t	ev,
		void *	data
	)

Post an asynchronous event.

This function posts an asynchronous event to one or more processes. The handing of the event is deferred until the target process is scheduled by the kernel. An event can be broadcast to all processes, in which case all processes in the system will be scheduled to handle the event.

Parameters

ev	The event to be posted.
data	The auxiliary data to be sent with the event
p	The process to which the event should be posted, or PROCESS_BROADCAST if the event should be posted to all processes.

Return values

PROCESS_ERR_OK	The event could be posted.
PROCESS_ERR_FULL	The event queue was full and the event could not be posted.

Definition at line 327 of file process.c.

References data, pm_wakeup(), PROCESS_CURRENT, PROCESS_ERR_FULL, and PROCESS_ERR_OK.

Referenced by tcpip_input().

CCIF void process_post_synch	(	struct process *	p,
		process_event_t	ev,
		void *	data
	)

Post a synchronous event to a process.

Parameters

p	A pointer to the process' process structure.
ev	The event to be posted.
data	A pointer to additional data that is posted together with the event.

Definition at line 374 of file process.c.

Referenced by process_start(), tcpip_input(), and tcpip_output().

CCIF int process_abort_event	(	struct process *	p,
		process_event_t	ev,
		void **	pdata
	)

Remove an event from the process queue.

Parameters

p	A pointer to the process' process structure.
ev	The event to remove.
pdata	A pointer tp the pointer wich receives data, originally assigned to the event.

Return values

1	if the event was removed, 0 if the event was not found.

Definition at line 383 of file process.c.

CCIF void process_exit

(

struct process *

p

)

Cause a process to exit.

Parameters

p	The process that is to be exited This function causes a process to exit. The process can either be the currently executing process, or another process that is currently running.

See also

PROCESS_CURRENT()

Definition at line 203 of file process.c.

References PROCESS_CURRENT.

CCIF process_event_t process_alloc_event

(

void

)

Allocate a global event number.

Returns

The allocated event number

        In Contiki, event numbers above 128 are global and may
        be posted from one process to another. This function
        allocates one such event number.

Note

There currently is no way to deallocate an allocated event number.

Definition at line 94 of file process.c.

Referenced by tcpip_input().

CCIF void process_poll

(

struct process *

p

)

Request a process to be polled.

This function typically is called from an interrupt handler to cause a process to be polled.

Parameters

p	A pointer to the process' process structure.

Definition at line 416 of file process.c.

References pm_wakeup().

Referenced by etimer_request_poll().

void process_init

(

void

)

Initialize the process module.

This function initializes the process module and should be called by the system boot-up code.

Definition at line 209 of file process.c.

References data.

int process_run

(

void

)

Run the system once - call poll handlers and process one event.

This function should be called repeatedly from the main() program to actually run the Contiki system. It calls the necessary poll handlers, and processes one event. The function returns the number of events that are waiting in the event queue so that the caller may choose to put the CPU to sleep when there are no pending events.

Returns

The number of events that are currently waiting in the event queue.

Definition at line 307 of file process.c.

CCIF int process_is_running

(

struct process *

p

)

Check if a process is running.

This function checks if a specific process is running.

Parameters

p	The process.

Return values

Non-zero	if the process is running.
Zero	if the process is not running.

Definition at line 429 of file process.c.

Referenced by process_start().

int process_nevents

(

void

)

Number of events waiting to be processed.

Returns

The number of events that are currently waiting to be processed.

Definition at line 321 of file process.c.