A process in Contiki consists of a single protothread.

Data Structures
struct	event_data

struct	process

Files
file	process.c
	Implementation of the Contiki process kernel.

file	process.h
	Header file for the Contiki process interface.

Macros
#define	_DEBUG_ 0

#define	PRINTF(...)

#define	PROCESS_BROADCAST NULL

#define	PROCESS_CONF_NUMEVENTS 32

#define	PROCESS_EVENT_COM 0x89

#define	PROCESS_EVENT_CONTINUE 0x85

#define	PROCESS_EVENT_EXIT 0x83

#define	PROCESS_EVENT_EXITED 0x87

#define	PROCESS_EVENT_INIT 0x81

#define	PROCESS_EVENT_MAX 0x8a

#define	PROCESS_EVENT_MSG 0x86

#define	PROCESS_EVENT_NONE 0x80

#define	PROCESS_EVENT_POLL 0x82

#define	PROCESS_EVENT_SERVICE_REMOVED 0x84

#define	PROCESS_EVENT_TIMER 0x88

#define	PROCESS_LIST() process_list

#define	PROCESS_NONE NULL

#define	PROCESS_STATE_CALLED 2

#define	PROCESS_STATE_NONE 0

#define	PROCESS_STATE_RUNNING 1

#define	PROCESS_ZOMBIE ((struct process *)0x1)

Typedefs
typedef void *	process_data_t

typedef unsigned char	process_event_t

typedef unsigned char	process_num_events_t

Functions
static void	call_process (struct process *p, process_event_t ev, process_data_t data)

static void	do_event (void)

static void	do_poll (void)

static void	exit_process (struct process p, struct process fromprocess)

Variables
static struct event_data	events [PROCESS_CONF_NUMEVENTS]

static process_num_events_t	fevent

static process_event_t	lastevent

static process_num_events_t	nevents

static volatile unsigned char	poll_requested

struct process *	process_current = NULL

struct process *	process_list = NULL

CCIF struct process *	process_list

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 the beginning of a process. More...

#define	PROCESS_END()
	Define the end of a process. More...

#define	PROCESS_WAIT_EVENT()
	Wait for an event to be posted to the process. More...

#define	PROCESS_WAIT_EVENT_UNTIL(c)
	Wait for an event to be posted to the process, with an extra condition. More...

#define	PROCESS_YIELD()
	Yield the currently running process. More...

#define	PROCESS_YIELD_UNTIL(c)
	Yield the currently running process until a condition occurs. More...

#define	PROCESS_WAIT_UNTIL(c)
	Wait for a condition to occur. More...

#define	PROCESS_WAIT_WHILE(c) PT_WAIT_WHILE(process_pt, c)

#define	PROCESS_EXIT()
	Exit the currently running process. More...

#define	PROCESS_PT_SPAWN(pt, thread)
	Spawn a protothread from the process. More...

#define	PROCESS_PAUSE()
	Yield the process for a short while. More...

Poll and exit handlers
#define	PROCESS_POLLHANDLER(handler)
	Specify an action when a process is polled. More...

#define	PROCESS_EXITHANDLER(handler)
	Specify an action when a process exits. More...

Process declaration and definition
#define	PROCESS_THREAD(name, ev, data)
	Define the body of a process. More...

#define	PROCESS_NAME(name)
	Declare the name of a process. More...

#define	PROCESS(name, strname)
	Declare a process. More...

Functions called from application programs
CCIF struct process *	process_current

process_event_t	process_alloc_event (void)
	Allocate a global event number. More...

void	process_start (struct process p, const char arg)
	Start a process. More...

void	process_exit (struct process *p)
	Cause a process to exit. More...

int	process_post (struct process p, process_event_t ev, void data)
	Post an asynchronous event. More...

void	process_post_synch (struct process p, process_event_t ev, void data)
	Post a synchronous event to a process. More...

#define	PROCESS_CURRENT()
	Get a pointer to the currently running process. More...

#define	PROCESS_CONTEXT_BEGIN(p)
	Switch context to another process. More...

#define	PROCESS_CONTEXT_END(p) process_current = tmp_current; }
	End a context switch. More...

Functions called from device drivers
void	process_poll (struct process *p)
	Request a process to be polled. More...

Functions called by the system and boot-up code
void	process_init (void)
	Initialize the process module. More...

int	process_run (void)
	Run the system once - call poll handlers and process one event. More...

int	process_nevents (void)
	Number of events waiting to be processed. More...

int	process_is_running (struct process *p)
	Check if a process is running. More...

#define _DEBUG_ 0

#define PRINTF ( ... )

Referenced by best_parent(), calculate_rank(), call_process(), check_prefix(), create_rpl_dag(), dao_ack_input(), dao_ack_output(), dao_input(), dao_output(), dao_output_target(), dio_input(), dio_output(), dis_input(), dis_output(), eventhandler(), exit_process(), ext_hdr_options_process(), global_repair(), handle_dao_timer(), handle_dio_timer(), init(), input_callback(), ip64_eth_interface_input(), na_input(), neighbor_link_callback(), new_dio_interval(), ns_input(), nullify_parents(), output(), packet_input(), process_post(), process_start(), PROCESS_THREAD(), ra_input(), remove_ext_hdr(), remove_parents(), reset(), rm_routelist(), rpl_add_dag(), rpl_add_parent(), rpl_add_route(), rpl_free_dag(), rpl_free_instance(), rpl_init(), rpl_invert_header(), rpl_ipv6_neighbor_callback(), rpl_join_instance(), rpl_link_neighbor_callback(), rpl_local_repair(), rpl_move_parent(), rpl_nullify_parent(), rpl_process_dio(), rpl_process_parent_event(), rpl_purge_routes(), rpl_recalculate_ranks(), rpl_remove_header(), rpl_remove_parent(), rpl_repair_root(), rpl_select_dag(), rpl_set_default_route(), rpl_set_mode(), rpl_set_preferred_parent(), rpl_set_prefix(), rpl_set_root(), rpl_update_header_empty(), rpl_update_header_final(), rpl_verify_header(), schedule_dao(), send_data(), set_dao_lifetime_timer(), start_get(), tcpip_ipv6_output(), uip_ds6_defrt_add(), uip_ds6_defrt_choose(), uip_ds6_defrt_periodic(), uip_ds6_defrt_rm(), uip_ds6_init(), uip_ds6_link_neighbor_callback(), uip_ds6_nbr_add(), uip_ds6_neighbor_periodic(), uip_ds6_prefix_add(), uip_ds6_route_add(), uip_ds6_route_lookup(), uip_ds6_route_rm(), uip_ds6_send_rs(), uip_ipchksum(), uip_nd6_ns_output(), uip_nd6_rs_output(), uip_process(), uiplib_ip6addrconv(), upper_layer_chksum(), websocket_http_client_aborted(), websocket_http_client_closed(), websocket_http_client_connected(), websocket_http_client_datahandler(), websocket_http_client_timedout(), and websocket_open().

#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.

#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.

Referenced by PROCESS_THREAD().

#define PROCESS_BROADCAST NULL

Referenced by do_event(), process_post(), and PROCESS_THREAD().

#define PROCESS_CONF_NUMEVENTS 32

Referenced by do_event(), and process_post().

#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()

Referenced by ctimer_reset(), ctimer_restart(), ctimer_set(), PROCESS_THREAD(), servreg_hack_register(), simple_udp_register(), start_timeout_timer(), tcp_socket_connect(), tcp_socket_listen(), tcp_socket_unlisten(), udp_socket_register(), and websocket_open().

#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()

Referenced by ctimer_reset(), ctimer_restart(), ctimer_set(), PROCESS_THREAD(), servreg_hack_register(), simple_udp_register(), start_timeout_timer(), tcp_socket_connect(), tcp_socket_listen(), tcp_socket_unlisten(), udp_socket_register(), and websocket_open().

#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().

Referenced by add_timer(), ctimer_set(), process_exit(), process_post(), PROCESS_THREAD(), and udp_socket_register().

#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.

Referenced by PROCESS_THREAD().

#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.

Referenced by process_post().

#define PROCESS_ERR_OK 0

Return value indicating that an operation was successful.

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

Referenced by process_post(), and PROCESS_THREAD().

#define PROCESS_EVENT_COM 0x89

#define PROCESS_EVENT_CONTINUE 0x85

Referenced by PROCESS_THREAD().

#define PROCESS_EVENT_EXIT 0x83

Referenced by call_process(), and exit_process().

#define PROCESS_EVENT_EXITED 0x87

Referenced by eventhandler(), exit_process(), and PROCESS_THREAD().

#define PROCESS_EVENT_INIT 0x81

Referenced by do_event(), and process_start().

#define PROCESS_EVENT_MAX 0x8a

Referenced by process_init().

#define PROCESS_EVENT_MSG 0x86

Referenced by PROCESS_THREAD(), uaodv_bad_dest(), and uaodv_request_route_to().

#define PROCESS_EVENT_NONE 0x80

Referenced by dhcpc_request(), and ip64_dhcpc_request().

#define PROCESS_EVENT_POLL 0x82

Referenced by do_poll(), and PROCESS_THREAD().

#define PROCESS_EVENT_SERVICE_REMOVED 0x84

#define PROCESS_EVENT_TIMER 0x88

Referenced by dhcpc_appcall(), eventhandler(), ip64_dhcpc_appcall(), and PROCESS_THREAD().

#define PROCESS_EXIT ( )

Exit the currently running process.

#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.

Referenced by PROCESS_THREAD().

#define PROCESS_LIST ( ) process_list

#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.

#define PROCESS_NONE NULL

Referenced by add_timer(), ctimer_stop(), etimer_expired(), etimer_stop(), eventhandler(), PROCESS_THREAD(), and tcpip_uipcall().

#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.

#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.

#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()

#define PROCESS_STATE_CALLED 2

Referenced by call_process(), and process_poll().

#define PROCESS_STATE_NONE 0

Referenced by exit_process(), and process_is_running().

#define PROCESS_STATE_RUNNING 1

Referenced by call_process(), do_event(), do_poll(), process_poll(), and process_start().

#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.

#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.

Referenced by PROCESS_THREAD().

#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()

Referenced by PROCESS_THREAD().

#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.

Referenced by PROCESS_THREAD().

#define PROCESS_WAIT_WHILE ( c ) PT_WAIT_WHILE(process_pt, c)

#define PROCESS_YIELD ( )

Yield the currently running process.

Referenced by PROCESS_THREAD().

#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.

Referenced by PROCESS_THREAD().

#define PROCESS_ZOMBIE ((struct process *)0x1)

typedef void* process_data_t

typedef unsigned char process_event_t

typedef unsigned char process_num_events_t

static void call_process	(	struct process *	p,
		process_event_t	ev,
		process_data_t	data
	)

static

References exit_process(), NULL, printf, PRINTF, PROCESS_EVENT_EXIT, PROCESS_NAME_STRING, PROCESS_STATE_CALLED, PROCESS_STATE_RUNNING, pt, PT_ENDED, PT_EXITED, ret, and state.

Referenced by do_event(), do_poll(), exit_process(), and process_post_synch().

static void do_event ( void )

static

References call_process(), event_data::data, data, do_poll(), event_data::ev, events, fevent, nevents, next, NULL, event_data::p, poll_requested, PROCESS_BROADCAST, PROCESS_CONF_NUMEVENTS, PROCESS_EVENT_INIT, PROCESS_STATE_RUNNING, receiver(), and state.

Referenced by process_run().

static void do_poll ( void )

static

References call_process(), needspoll, next, NULL, poll_requested, PROCESS_EVENT_POLL, PROCESS_STATE_RUNNING, and state.

Referenced by do_event(), and process_run().

static void exit_process	(	struct process *	p,
		struct process *	fromprocess
	)

static

References call_process(), next, NULL, PRINTF, process_current, PROCESS_EVENT_EXIT, PROCESS_EVENT_EXITED, process_is_running(), PROCESS_NAME_STRING, PROCESS_STATE_NONE, pt, and state.

Referenced by call_process(), and process_exit().

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.

References lastevent.

Referenced by PROCESS_THREAD().

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()

References exit_process(), and PROCESS_CURRENT.

Referenced by autostart_exit().

void process_init ( void )

Initialize the process module.

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

References fevent, lastevent, nevents, NULL, and PROCESS_EVENT_MAX.

Referenced by main().

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.

References PROCESS_STATE_NONE, and state.

Referenced by exit_process().

int process_nevents ( void )

Number of events waiting to be processed.

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

References nevents, and poll_requested.

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.

References needspoll, NULL, poll_requested, PROCESS_STATE_CALLED, PROCESS_STATE_RUNNING, and state.

Referenced by etimer_request_poll(), rf212_interrupt_poll(), rf233_interrupt_poll(), sensors_changed(), serial_line_input_byte(), slip_input_byte(), and slip_poll_handler().

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.

References event_data::data, data, event_data::ev, events, fevent, nevents, NULL, event_data::p, printf, PRINTF, PROCESS_BROADCAST, PROCESS_CONF_NUMEVENTS, PROCESS_CURRENT, PROCESS_ERR_FULL, PROCESS_ERR_OK, and PROCESS_NAME_STRING.

Referenced by PROCESS_THREAD(), uaodv_bad_dest(), and uaodv_request_route_to().

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.

References call_process(), and process_current.

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

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.