src/charon/queues/event_queue.c

   1 /**
   2  * @file event_queue.c
   3  *
   4  * @brief Implementation of event_queue_t
   5  *
   6  */
   7
   8 /*
   9  * Copyright (C) 2005-2006 Martin Willi
  10  * Copyright (C) 2005 Jan Hutter
  11  * Hochschule fuer Technik Rapperswil
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms of the GNU General Public License as published by the
  15  * Free Software Foundation; either version 2 of the License, or (at your
  16  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  17  *
  18  * This program is distributed in the hope that it will be useful, but
  19  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  20  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  21  * for more details.
  22  */
  23
  24 #include <pthread.h>
  25 #include <stdlib.h>
  26
  27 #include "event_queue.h"
  28
  29 #include <library.h>
  30 #include <utils/linked_list.h>
  31
  32
  33
  34 typedef struct event_t event_t;
  35
  36 /**
  37  * Event containing a job and a schedule time
  38  */
  39 struct event_t {
  40         /**
  41          * Time to fire the event.
  42          */
  43         timeval_t time;
  44
  45         /**
  46          * Every event has its assigned job.
  47          */
  48         job_t * job;
  49 };
  50
  51 /**
  52  * destroy an event and its job
  53  */
  54 static void event_destroy(event_t *event)
  55 {
  56         event->job->destroy(event->job);
  57         free(event);
  58 }
  59
  60 typedef struct private_event_queue_t private_event_queue_t;
  61
  62 /**
  63  * Private Variables and Functions of event_queue_t class.
  64  */
  65 struct private_event_queue_t {
  66         /**
  67          * Public part.
  68          */
  69         event_queue_t public;
  70
  71         /**
  72          * The events are stored in a linked list of type linked_list_t.
  73          */
  74         linked_list_t *list;
  75
  76         /**
  77          * Access to linked_list is locked through this mutex.
  78          */
  79         pthread_mutex_t mutex;
  80
  81         /**
  82          * If the queue is empty or an event has not to be fired
  83          * a thread has to wait.
  84          *
  85          * This condvar is used to wake up such a thread.
  86          */
  87         pthread_cond_t condvar;
  88 };
  89
  90 /**
  91  * Returns the difference of to timeval structs in milliseconds
  92  */
  93 static long time_difference(struct timeval *end_time, struct timeval *start_time)
  94 {
  95         time_t s;
  96         suseconds_t us;
  97
  98         s = (end_time->tv_sec - start_time->tv_sec);
  99         us = (end_time->tv_usec - start_time->tv_usec);
 100         return ((s * 1000) + us/1000);
 101 }
 102
 103 /**
 104  * Implements event_queue_t.get_count
 105  */
 106 static int get_count(private_event_queue_t *this)
 107 {
 108         int count;
 109         pthread_mutex_lock(&(this->mutex));
 110         count = this->list->get_count(this->list);
 111         pthread_mutex_unlock(&(this->mutex));
 112         return count;
 113 }
 114
 115 /**
 116  * Implements event_queue_t.get
 117  */
 118 static job_t *get(private_event_queue_t *this)
 119 {
 120         timespec_t timeout;
 121         timeval_t current_time;
 122         event_t * next_event;
 123         job_t *job;
 124         int oldstate;
 125
 126         pthread_mutex_lock(&(this->mutex));
 127
 128         while (TRUE)
 129         {
 130                 while(this->list->get_count(this->list) == 0)
 131                 {
 132                         /* add mutex unlock handler for cancellation, enable cancellation */
 133                         pthread_cleanup_push((void(*)(void*))pthread_mutex_unlock, (void*)&(this->mutex));
 134                         pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
 135
 136                         pthread_cond_wait( &(this->condvar), &(this->mutex));
 137
 138                         /* reset cancellation, remove mutex-unlock handler (without executing) */
 139                         pthread_setcancelstate(oldstate, NULL);
 140                         pthread_cleanup_pop(0);
 141                 }
 142
 143                 this->list->get_first(this->list, (void **)&next_event);
 144
 145                 gettimeofday(&current_time, NULL);
 146                 long difference = time_difference(&current_time,&(next_event->time));
 147                 if (difference <= 0)
 148                 {
 149                         timeout.tv_sec = next_event->time.tv_sec;
 150                         timeout.tv_nsec = next_event->time.tv_usec * 1000;
 151
 152                         /* add mutex unlock handler for cancellation, enable cancellation */
 153                         pthread_cleanup_push((void(*)(void*))pthread_mutex_unlock, (void*)&(this->mutex));
 154                         pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
 155
 156                         pthread_cond_timedwait(&(this->condvar), &(this->mutex), &timeout);
 157
 158                         /* reset cancellation, remove mutex-unlock handler (without executing) */
 159                         pthread_setcancelstate(oldstate, NULL);
 160                         pthread_cleanup_pop(0);
 161                 }
 162                 else
 163                 {
 164                         /* event available */
 165                         this->list->remove_first(this->list, (void **)&next_event);
 166                         job = next_event->job;
 167                         free(next_event);
 168                         break;
 169                 }
 170         }
 171         pthread_cond_signal( &(this->condvar));
 172         pthread_mutex_unlock(&(this->mutex));
 173
 174         return job;
 175 }
 176
 177 /**
 178  * Implements function add_absolute of event_queue_t.
 179  * See #event_queue_s.add_absolute for description.
 180  */
 181 static void add_absolute(private_event_queue_t *this, job_t *job, timeval_t time)
 182 {
 183         event_t *event;
 184         event_t *current_event;
 185         iterator_t *iterator;
 186
 187         /* create event */
 188         event = malloc_thing(event_t);
 189         event->time = time;
 190         event->job = job;
 191
 192         pthread_mutex_lock(&(this->mutex));
 193
 194         /* while just used to break out */
 195         while(TRUE)
 196         {
 197                 if (this->list->get_count(this->list) == 0)
 198                 {
 199                         this->list->insert_first(this->list,event);
 200                         break;
 201                 }
 202
 203                 /* check last entry */
 204                 this->list->get_last(this->list,(void **) &current_event);
 205
 206                 if (time_difference(&(event->time), &(current_event->time)) >= 0)
 207                 {
 208                         /* my event has to be fired after the last event in list */
 209                         this->list->insert_last(this->list,event);
 210                         break;
 211                 }
 212
 213                 /* check first entry */
 214                 this->list->get_first(this->list,(void **) &current_event);
 215
 216                 if (time_difference(&(event->time), &(current_event->time)) < 0)
 217                 {
 218                         /* my event has to be fired before the first event in list */
 219                         this->list->insert_first(this->list,event);
 220                         break;
 221                 }
 222
 223                 iterator = this->list->create_iterator(this->list,TRUE);
 224                 iterator->iterate(iterator, (void**)&current_event);
 225                 /* first element has not to be checked (already done) */
 226                 while(iterator->iterate(iterator, (void**)&current_event))
 227                 {
 228                         if (time_difference(&(event->time), &(current_event->time)) <= 0)
 229                         {
 230                                 /* my event has to be fired before the current event in list */
 231                                 iterator->insert_before(iterator,event);
 232                                 break;
 233                         }
 234                 }
 235                 iterator->destroy(iterator);
 236                 break;
 237         }
 238
 239         pthread_cond_signal( &(this->condvar));
 240         pthread_mutex_unlock(&(this->mutex));
 241 }
 242
 243 /**
 244  * Implements  event_queue_t.add_relative.
 245  */
 246 static void add_relative(event_queue_t *this, job_t *job, u_int32_t ms)
 247 {
 248         timeval_t current_time;
 249         timeval_t time;
 250
 251         time_t s = ms / 1000;
 252         suseconds_t us = (ms - s * 1000) * 1000;
 253
 254         gettimeofday(&current_time, NULL);
 255
 256         time.tv_usec = (current_time.tv_usec + us) % 1000000;
 257         time.tv_sec = current_time.tv_sec + (current_time.tv_usec + us)/1000000 + s;
 258
 259         this->add_absolute(this, job, time);
 260 }
 261
 262
 263 /**
 264  * Implements event_queue_t.destroy.
 265  */
 266 static void event_queue_destroy(private_event_queue_t *this)
 267 {
 268         this->list->destroy_function(this->list, (void*)event_destroy);
 269         free(this);
 270 }
 271
 272 /*
 273  * Documented in header
 274  */
 275 event_queue_t *event_queue_create()
 276 {
 277         private_event_queue_t *this = malloc_thing(private_event_queue_t);
 278
 279         this->public.get_count = (int (*) (event_queue_t *event_queue)) get_count;
 280         this->public.get = (job_t *(*) (event_queue_t *event_queue)) get;
 281         this->public.add_absolute = (void (*) (event_queue_t *event_queue, job_t *job, timeval_t time)) add_absolute;
 282         this->public.add_relative = (void (*) (event_queue_t *event_queue, job_t *job, u_int32_t ms)) add_relative;
 283         this->public.destroy = (void (*) (event_queue_t *event_queue)) event_queue_destroy;
 284
 285         this->list = linked_list_create();
 286         pthread_mutex_init(&(this->mutex), NULL);
 287         pthread_cond_init(&(this->condvar), NULL);
 288
 289         return (&this->public);
 290 }