390 lines
11 KiB
C
390 lines
11 KiB
C
/*
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* Copyright (c) 2005, Swedish Institute of Computer Science
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* This file is part of the Contiki operating system.
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*
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* @(#)$Id: process.c,v 1.12 2010/10/20 22:24:46 adamdunkels Exp $
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*/
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/**
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* \addtogroup process
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* @{
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*/
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/**
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* \file
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* Implementation of the Contiki process kernel.
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* \author
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* Adam Dunkels <adam@sics.se>
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*
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*/
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#include <stdio.h>
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#include "sys/process.h"
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#include "sys/arg.h"
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/*
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* Pointer to the currently running process structure.
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*/
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struct process *process_list = NULL;
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struct process *process_current = NULL;
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static process_event_t lastevent;
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/*
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* Structure used for keeping the queue of active events.
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*/
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struct event_data {
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process_event_t ev;
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process_data_t data;
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struct process *p;
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};
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static process_num_events_t nevents, fevent;
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static struct event_data events[PROCESS_CONF_NUMEVENTS];
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#if PROCESS_CONF_STATS
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process_num_events_t process_maxevents;
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#endif
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static volatile unsigned char poll_requested;
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#define PROCESS_STATE_NONE 0
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#define PROCESS_STATE_RUNNING 1
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#define PROCESS_STATE_CALLED 2
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static void call_process(struct process *p, process_event_t ev, process_data_t data);
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#define DEBUG 0
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#if DEBUG
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#include <stdio.h>
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#define PRINTF(...) printf(__VA_ARGS__)
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#else
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#define PRINTF(...)
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#endif
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/*---------------------------------------------------------------------------*/
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process_event_t
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process_alloc_event(void)
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{
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return lastevent++;
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}
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/*---------------------------------------------------------------------------*/
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void
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process_start(struct process *p, const char *arg)
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{
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struct process *q;
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/* First make sure that we don't try to start a process that is
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already running. */
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for(q = process_list; q != p && q != NULL; q = q->next);
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/* If we found the process on the process list, we bail out. */
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if(q == p) {
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return;
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}
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/* Put on the procs list.*/
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p->next = process_list;
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process_list = p;
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p->state = PROCESS_STATE_RUNNING;
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PT_INIT(&p->pt);
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PRINTF("process: starting '%s'\n", PROCESS_NAME_STRING(p));
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/* Post a synchronous initialization event to the process. */
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process_post_synch(p, PROCESS_EVENT_INIT, (process_data_t)arg);
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}
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/*---------------------------------------------------------------------------*/
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static void
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exit_process(struct process *p, struct process *fromprocess)
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{
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register struct process *q;
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struct process *old_current = process_current;
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PRINTF("process: exit_process '%s'\n", PROCESS_NAME_STRING(p));
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/* Make sure the process is in the process list before we try to
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exit it. */
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for(q = process_list; q != p && q != NULL; q = q->next);
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if(q == NULL) {
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return;
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}
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if(process_is_running(p)) {
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/* Process was running */
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p->state = PROCESS_STATE_NONE;
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/*
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* Post a synchronous event to all processes to inform them that
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* this process is about to exit. This will allow services to
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* deallocate state associated with this process.
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*/
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for(q = process_list; q != NULL; q = q->next) {
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if(p != q) {
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call_process(q, PROCESS_EVENT_EXITED, (process_data_t)p);
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}
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}
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if(p->thread != NULL && p != fromprocess) {
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/* Post the exit event to the process that is about to exit. */
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process_current = p;
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p->thread(&p->pt, PROCESS_EVENT_EXIT, NULL);
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}
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}
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if(p == process_list) {
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process_list = process_list->next;
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} else {
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for(q = process_list; q != NULL; q = q->next) {
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if(q->next == p) {
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q->next = p->next;
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break;
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}
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}
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}
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process_current = old_current;
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}
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/*---------------------------------------------------------------------------*/
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static void
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call_process(struct process *p, process_event_t ev, process_data_t data)
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{
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int ret;
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#if DEBUG
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if(p->state == PROCESS_STATE_CALLED) {
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printf("process: process '%s' called again with event %d\n", PROCESS_NAME_STRING(p), ev);
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}
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#endif /* DEBUG */
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if((p->state & PROCESS_STATE_RUNNING) &&
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p->thread != NULL) {
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PRINTF("process: calling process '%s' with event %d\n", PROCESS_NAME_STRING(p), ev);
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process_current = p;
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p->state = PROCESS_STATE_CALLED;
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ret = p->thread(&p->pt, ev, data);
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if(ret == PT_EXITED ||
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ret == PT_ENDED ||
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ev == PROCESS_EVENT_EXIT) {
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exit_process(p, p);
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} else {
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p->state = PROCESS_STATE_RUNNING;
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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void
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process_exit(struct process *p)
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{
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exit_process(p, PROCESS_CURRENT());
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}
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/*---------------------------------------------------------------------------*/
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void
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process_init(void)
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{
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lastevent = PROCESS_EVENT_MAX;
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nevents = fevent = 0;
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#if PROCESS_CONF_STATS
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process_maxevents = 0;
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#endif /* PROCESS_CONF_STATS */
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process_current = process_list = NULL;
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}
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/*---------------------------------------------------------------------------*/
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/*
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* Call each process' poll handler.
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*/
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/*---------------------------------------------------------------------------*/
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static void
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do_poll(void)
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{
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struct process *p;
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poll_requested = 0;
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/* Call the processes that needs to be polled. */
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for(p = process_list; p != NULL; p = p->next) {
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if(p->needspoll) {
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p->state = PROCESS_STATE_RUNNING;
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p->needspoll = 0;
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call_process(p, PROCESS_EVENT_POLL, NULL);
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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/*
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* Process the next event in the event queue and deliver it to
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* listening processes.
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*/
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/*---------------------------------------------------------------------------*/
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static void
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do_event(void)
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{
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static process_event_t ev;
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static process_data_t data;
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static struct process *receiver;
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static struct process *p;
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/*
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* If there are any events in the queue, take the first one and walk
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* through the list of processes to see if the event should be
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* delivered to any of them. If so, we call the event handler
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* function for the process. We only process one event at a time and
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* call the poll handlers inbetween.
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*/
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if(nevents > 0) {
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/* There are events that we should deliver. */
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ev = events[fevent].ev;
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data = events[fevent].data;
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receiver = events[fevent].p;
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/* Since we have seen the new event, we move pointer upwards
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and decrese the number of events. */
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fevent = (fevent + 1) % PROCESS_CONF_NUMEVENTS;
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--nevents;
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/* If this is a broadcast event, we deliver it to all events, in
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order of their priority. */
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if(receiver == PROCESS_BROADCAST) {
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for(p = process_list; p != NULL; p = p->next) {
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/* If we have been requested to poll a process, we do this in
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between processing the broadcast event. */
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if(poll_requested) {
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do_poll();
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}
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call_process(p, ev, data);
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}
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} else {
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/* This is not a broadcast event, so we deliver it to the
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specified process. */
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/* If the event was an INIT event, we should also update the
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state of the process. */
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if(ev == PROCESS_EVENT_INIT) {
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receiver->state = PROCESS_STATE_RUNNING;
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}
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/* Make sure that the process actually is running. */
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call_process(receiver, ev, data);
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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int
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process_run(void)
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{
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/* Process poll events. */
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if(poll_requested) {
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do_poll();
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}
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/* Process one event from the queue */
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do_event();
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return nevents + poll_requested;
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}
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/*---------------------------------------------------------------------------*/
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int
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process_nevents(void)
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{
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return nevents + poll_requested;
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}
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/*---------------------------------------------------------------------------*/
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int
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process_post(struct process *p, process_event_t ev, process_data_t data)
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{
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static process_num_events_t snum;
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if(PROCESS_CURRENT() == NULL) {
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PRINTF("process_post: NULL process posts event %d to process '%s', nevents %d\n",
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ev,PROCESS_NAME_STRING(p), nevents);
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} else {
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PRINTF("process_post: Process '%s' posts event %d to process '%s', nevents %d\n",
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PROCESS_NAME_STRING(PROCESS_CURRENT()), ev,
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p == PROCESS_BROADCAST? "<broadcast>": PROCESS_NAME_STRING(p), nevents);
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}
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if(nevents == PROCESS_CONF_NUMEVENTS) {
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#if DEBUG
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if(p == PROCESS_BROADCAST) {
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printf("soft panic: event queue is full when broadcast event %d was posted from %s\n", ev, PROCESS_NAME_STRING(process_current));
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} else {
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printf("soft panic: event queue is full when event %d was posted to %s frpm %s\n", ev, PROCESS_NAME_STRING(p), PROCESS_NAME_STRING(process_current));
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}
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#endif /* DEBUG */
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return PROCESS_ERR_FULL;
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}
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snum = (process_num_events_t)(fevent + nevents) % PROCESS_CONF_NUMEVENTS;
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events[snum].ev = ev;
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events[snum].data = data;
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events[snum].p = p;
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++nevents;
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#if PROCESS_CONF_STATS
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if(nevents > process_maxevents) {
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process_maxevents = nevents;
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}
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#endif /* PROCESS_CONF_STATS */
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return PROCESS_ERR_OK;
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}
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/*---------------------------------------------------------------------------*/
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void
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process_post_synch(struct process *p, process_event_t ev, process_data_t data)
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{
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struct process *caller = process_current;
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call_process(p, ev, data);
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process_current = caller;
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}
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/*---------------------------------------------------------------------------*/
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void
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process_poll(struct process *p)
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{
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if(p != NULL) {
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if(p->state == PROCESS_STATE_RUNNING ||
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p->state == PROCESS_STATE_CALLED) {
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p->needspoll = 1;
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poll_requested = 1;
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}
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}
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}
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/*---------------------------------------------------------------------------*/
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int
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process_is_running(struct process *p)
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{
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return p->state != PROCESS_STATE_NONE;
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}
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/*---------------------------------------------------------------------------*/
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/** @} */
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