Source/charon/event_queue.c

   1 /**
   2  * @file event_queue.c
   3  *
   4  * @brief Event-Queue based on linked_list_t
   5  *
   6  */
   7
   8 /*
   9  * Copyright (C) 2005 Jan Hutter, Martin Willi
  10  * Hochschule fuer Technik Rapperswil
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU General Public License as published by the
  14  * Free Software Foundation; either version 2 of the License, or (at your
  15  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  */
  22
  23 #include <freeswan.h>
  24 #include <pluto/constants.h>
  25 #include <pluto/defs.h>
  26 #include <pthread.h>
  27 #include <stdlib.h>
  28
  29 #include "allocator.h"
  30 #include "types.h"
  31 #include "event_queue.h"
  32 #include "linked_list.h"
  33
  34
  35
  36 /**
  37  * @brief represents an event as it is stored in the event queue
  38  *
  39  * A event consists of a event time and an assigned job object
  40  *
  41  */
  42 typedef struct event_s event_t;
  43
  44 struct event_s{
  45         /**
  46          * Time to fire the event
  47          */
  48         timeval_t time;
  49
  50         /**
  51          * Every event has its assigned job
  52          */
  53         job_t * job;
  54
  55         /**
  56          * @brief Destroys a event_t object
  57          *
  58          * @param event_t calling object
  59          * @returns SUCCESS if succeeded, FAILED otherwise
  60          */
  61         status_t (*destroy) (event_t *event);
  62 };
  63
  64
  65 /**
  66  * @brief implements function destroy of event_t
  67  */
  68 static status_t event_destroy(event_t *event)
  69 {
  70         if (event == NULL)
  71         {
  72                 return FAILED;
  73         }
  74         allocator_free(event);
  75         return SUCCESS;
  76 }
  77
  78 /**
  79  * @brief Creates a event for a specific time
  80  *
  81  * @param time to fire the event
  82  * @param job job to add to job-queue at specific time
  83  *
  84  * @return event_t event object
  85  */
  86 static event_t *event_create(timeval_t time, job_t *job)
  87 {
  88         event_t *this = allocator_alloc_thing(event_t);
  89
  90         this->destroy = event_destroy;
  91
  92         this->time = time;
  93         this->job = job;
  94
  95         return this;
  96 }
  97
  98
  99 /**
 100  * @brief Private Variables and Functions of event_queue class
 101  *
 102  */
 103 typedef struct private_event_queue_s private_event_queue_t;
 104
 105
 106 struct private_event_queue_s {
 107         event_queue_t public;
 108
 109         /**
 110          * The events are stored in a linked list
 111          */
 112         linked_list_t *list;
 113
 114         /**
 115          * access to linked_list is locked through this mutex
 116          */
 117         pthread_mutex_t mutex;
 118
 119         /**
 120          * If the queue is empty or an event has not to be fired
 121          * a thread has to wait
 122          * This condvar is used to wake up such a thread
 123          */
 124         pthread_cond_t condvar;
 125 };
 126
 127 /**
 128  * Returns the difference of to timeval structs in microseconds
 129  *
 130  * @param end_time end time
 131  * @param start_time start time
 132  *
 133  * @warning this function is also defined in the tester class
 134  *                      In later improvements, this function can be added to a general
 135  *          class type!
 136  *
 137  * @return difference in microseconds
 138  */
 139 static long time_difference(struct timeval *end_time, struct timeval *start_time)
 140 {
 141         long seconds, microseconds;
 142
 143         seconds = (end_time->tv_sec - start_time->tv_sec);
 144         microseconds = (end_time->tv_usec - start_time->tv_usec);
 145         return ((seconds * 1000000) + microseconds);
 146 }
 147
 148
 149 /**
 150  * @brief implements function get_count of event_queue_t
 151  */
 152 static status_t get_count (private_event_queue_t *this, int *count)
 153 {
 154         pthread_mutex_lock(&(this->mutex));
 155         status_t status = this->list->get_count(this->list,count);
 156         pthread_mutex_unlock(&(this->mutex));
 157         return status;
 158 }
 159
 160 /**
 161  * @brief implements function get of event_queue_t
 162  */
 163 static status_t get(private_event_queue_t *this, job_t **job)
 164 {
 165         timespec_t timeout;
 166         timeval_t current_time;
 167         event_t * next_event;
 168         int count;
 169         int oldstate;
 170
 171         pthread_mutex_lock(&(this->mutex));
 172
 173         while (1)
 174         {
 175                 this->list->get_count(this->list,&count);
 176                 while(count == 0)
 177                 {
 178                         /* add mutex unlock handler for cancellation, enable cancellation */
 179                         pthread_cleanup_push((void(*)(void*))pthread_mutex_unlock, (void*)&(this->mutex));
 180                         pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
 181
 182                         pthread_cond_wait( &(this->condvar), &(this->mutex));
 183
 184                         /* reset cancellation, remove mutex-unlock handler (without executing) */
 185                         pthread_setcancelstate(oldstate, NULL);
 186                         pthread_cleanup_pop(0);
 187
 188                         this->list->get_count(this->list,&count);
 189                 }
 190
 191                 this->list->get_first(this->list,(void **) &next_event);
 192
 193                 gettimeofday(&current_time,NULL);
 194                 long difference = time_difference(&current_time,&(next_event->time));
 195                 if (difference <= 0)
 196                 {
 197                         timeout.tv_sec = next_event->time.tv_sec;
 198             timeout.tv_nsec = next_event->time.tv_usec * 1000;
 199
 200                         pthread_cond_timedwait( &(this->condvar), &(this->mutex),&timeout);
 201                 }
 202                 else
 203                 {
 204                         /* event available */
 205                         this->list->remove_first(this->list,(void **) &next_event);
 206
 207                         *job = next_event->job;
 208
 209                         next_event->destroy(next_event);
 210                         break;
 211                 }
 212
 213         }
 214         pthread_cond_signal( &(this->condvar));
 215
 216         pthread_mutex_unlock(&(this->mutex));
 217
 218         return SUCCESS;
 219 }
 220
 221 /**
 222  * @brief implements function add of event_queue_t
 223  */
 224 static status_t add_absolute(private_event_queue_t *this, job_t *job, timeval_t time)
 225 {
 226         event_t *event = event_create(time,job);
 227         event_t *current_event;
 228         status_t status;
 229         int count;
 230
 231         if (event == NULL)
 232         {
 233                 return FAILED;
 234         }
 235         pthread_mutex_lock(&(this->mutex));
 236
 237         /* while just used to break out */
 238         while(1)
 239         {
 240                 this->list->get_count(this->list,&count);
 241                 if (count == 0)
 242                 {
 243                         status = this->list->insert_first(this->list,event);
 244                         break;
 245                 }
 246
 247                 /* check last entry */
 248                 this->list->get_last(this->list,(void **) &current_event);
 249
 250                 if (time_difference(&(event->time), &(current_event->time)) >= 0)
 251                 {
 252                         /* my event has to be fired after the last event in list */
 253                         status = this->list->insert_last(this->list,event);
 254                         break;
 255                 }
 256
 257                 /* check first entry */
 258                 this->list->get_first(this->list,(void **) &current_event);
 259
 260                 if (time_difference(&(event->time), &(current_event->time)) < 0)
 261                 {
 262                         /* my event has to be fired before the first event in list */
 263                         status = this->list->insert_first(this->list,event);
 264                         break;
 265                 }
 266
 267                 linked_list_iterator_t * iterator;
 268
 269                 status = this->list->create_iterator(this->list,&iterator,TRUE);
 270                 if (status != SUCCESS)
 271                 {
 272                         break;
 273                 }
 274
 275
 276                 iterator->has_next(iterator);
 277                 /* first element has not to be checked (already done) */
 278
 279                 while(iterator->has_next(iterator))
 280                 {
 281                         status = iterator->current(iterator,(void **) &current_event);
 282
 283                         if (time_difference(&(event->time), &(current_event->time)) <= 0)
 284                         {
 285                                 /* my event has to be fired before the current event in list */
 286                                 status = this->list->insert_before(this->list,iterator,event);
 287                                 break;
 288                         }
 289                 }
 290                 iterator->destroy(iterator);
 291                 break;
 292         }
 293
 294         pthread_cond_signal( &(this->condvar));
 295         pthread_mutex_unlock(&(this->mutex));
 296
 297         if (status != SUCCESS)
 298         {
 299                 event->destroy(event);
 300         }
 301         return status;
 302 }
 303
 304 /**
 305  * @brief implements function add of event_queue_t
 306  */
 307 static status_t add_relative(event_queue_t *this, job_t *job, u_int32_t ms)
 308 {
 309         timeval_t current_time;
 310         timeval_t time;
 311         int micros = ms * 1000;
 312
 313         gettimeofday(&current_time, NULL);
 314
 315         time.tv_usec = ((current_time.tv_usec + micros) % 1000000);
 316         time.tv_sec = current_time.tv_sec + ((current_time.tv_usec + micros)/ 1000000);
 317
 318         return this->add_absolute(this, job, time);
 319 }
 320
 321
 322 /**
 323  * @brief implements function destroy of event_queue_t
 324  */
 325 static status_t event_queue_destroy(private_event_queue_t *this)
 326 {
 327         int count;
 328         this->list->get_count(this->list,&count);
 329         while (count > 0)
 330         {
 331                 event_t *event;
 332
 333                 if (this->list->remove_first(this->list,(void *) &event) != SUCCESS)
 334                 {
 335                         this->list->destroy(this->list);
 336                         break;
 337                 }
 338                 event->job->destroy(event->job);
 339                 event->destroy(event);
 340                 this->list->get_count(this->list,&count);
 341         }
 342         this->list->destroy(this->list);
 343
 344         pthread_mutex_destroy(&(this->mutex));
 345
 346         pthread_cond_destroy(&(this->condvar));
 347
 348         allocator_free(this);
 349         return SUCCESS;
 350 }
 351
 352 /*
 353  *
 354  * Documented in header
 355  */
 356 event_queue_t *event_queue_create()
 357 {
 358         linked_list_t *linked_list = linked_list_create();
 359         if (linked_list == NULL)
 360         {
 361                 return NULL;
 362         }
 363
 364         private_event_queue_t *this = allocator_alloc_thing(private_event_queue_t);
 365         if (this == NULL)
 366         {
 367                 linked_list->destroy(linked_list);
 368                 return NULL;
 369         }
 370
 371         this->public.get_count = (status_t (*) (event_queue_t *event_queue, int *count)) get_count;
 372         this->public.get = (status_t (*) (event_queue_t *event_queue, job_t **job)) get;
 373         this->public.add_absolute = (status_t (*) (event_queue_t *event_queue, job_t *job, timeval_t time)) add_absolute;
 374         this->public.add_relative = (status_t (*) (event_queue_t *event_queue, job_t *job, u_int32_t ms)) add_relative;
 375         this->public.destroy = (status_t (*) (event_queue_t *event_queue)) event_queue_destroy;
 376
 377         this->list = linked_list;
 378         pthread_mutex_init(&(this->mutex), NULL);
 379         pthread_cond_init(&(this->condvar), NULL);
 380
 381         return (&this->public);
 382 }