citadel/threads.c

   1 /*
   2  * $Id$
   3  *
   4  * Citadel "system dependent" stuff.
   5  * See COPYING for copyright information.
   6  *
   7  * Here's where we have the Citadel thread implimentation
   8  *
   9  */
  10
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <stdio.h>
  14 #include <sys/types.h>
  15 #include <errno.h>
  16 #include <sys/socket.h>
  17 #include <unistd.h>
  18 #include <fcntl.h>
  19 #include <signal.h>
  20
  21 #if TIME_WITH_SYS_TIME
  22 # include <sys/time.h>
  23 # include <time.h>
  24 #else
  25 # if HAVE_SYS_TIME_H
  26 #  include <sys/time.h>
  27 # else
  28 #  include <time.h>
  29 # endif
  30 #endif
  31
  32 #include <libcitadel.h>
  33
  34 #include "threads.h"
  35 #include "ctdl_module.h"
  36 #include "modules_init.h"
  37 #include "housekeeping.h"
  38 #include "config.h"
  39 #include "citserver.h"
  40 #include "sysdep_decls.h"
  41 #include "context.h"
  42
  43 /*
  44  * define this to use the new worker_thread method of handling connections
  45  */
  46 //#define NEW_WORKER
  47
  48 /*
  49  * New thread interface.
  50  * To create a thread you must call one of the create thread functions.
  51  * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
  52  * struct CtdlThreadNode *node = NULL;
  53  * pass in &node
  54  * If the thread is created *node will point to the thread control structure for the created thread.
  55  * If the thread creation fails *node remains NULL
  56  * Do not free the memory pointed to by *node, it doesn't belong to you.
  57  * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
  58  * remove the need for the calls to eCrashRegisterThread and friends
  59  */
  60
  61 static int num_threads = 0;                     /* Current number of threads */
  62 static int num_workers = 0;                     /* Current number of worker threads */
  63 long statcount = 0;             /* are we doing a stats check? */
  64 static long stats_done = 0;
  65
  66 CtdlThreadNode *CtdlThreadList = NULL;
  67 CtdlThreadNode *CtdlThreadSchedList = NULL;
  68
  69 static CtdlThreadNode *GC_thread = NULL;
  70 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
  71 double CtdlThreadLoadAvg = 0;
  72 double CtdlThreadWorkerAvg = 0;
  73 citthread_key_t ThreadKey;
  74
  75 citthread_mutex_t Critters[MAX_SEMAPHORES];     /* Things needing locking */
  76
  77
  78
  79 void InitialiseSemaphores(void)
  80 {
  81         int i;
  82
  83         /* Set up a bunch of semaphores to be used for critical sections */
  84         for (i=0; i<MAX_SEMAPHORES; ++i) {
  85                 citthread_mutex_init(&Critters[i], NULL);
  86         }
  87 }
  88
  89
  90
  91
  92 /*
  93  * Obtain a semaphore lock to begin a critical section.
  94  * but only if no one else has one
  95  */
  96 int try_critical_section(int which_one)
  97 {
  98         /* For all types of critical sections except those listed here,
  99          * ensure nobody ever tries to do a critical section within a
 100          * transaction; this could lead to deadlock.
 101          */
 102         if (    (which_one != S_FLOORCACHE)
 103 #ifdef DEBUG_MEMORY_LEAKS
 104                 && (which_one != S_DEBUGMEMLEAKS)
 105 #endif
 106                 && (which_one != S_RPLIST)
 107         ) {
 108                 cdb_check_handles();
 109         }
 110         return (citthread_mutex_trylock(&Critters[which_one]));
 111 }
 112
 113
 114 /*
 115  * Obtain a semaphore lock to begin a critical section.
 116  */
 117 void begin_critical_section(int which_one)
 118 {
 119         /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
 120
 121         /* For all types of critical sections except those listed here,
 122          * ensure nobody ever tries to do a critical section within a
 123          * transaction; this could lead to deadlock.
 124          */
 125         if (    (which_one != S_FLOORCACHE)
 126 #ifdef DEBUG_MEMORY_LEAKS
 127                 && (which_one != S_DEBUGMEMLEAKS)
 128 #endif
 129                 && (which_one != S_RPLIST)
 130         ) {
 131                 cdb_check_handles();
 132         }
 133         citthread_mutex_lock(&Critters[which_one]);
 134 }
 135
 136 /*
 137  * Release a semaphore lock to end a critical section.
 138  */
 139 void end_critical_section(int which_one)
 140 {
 141         citthread_mutex_unlock(&Critters[which_one]);
 142 }
 143
 144
 145 /*
 146  * A function to destroy the TSD
 147  */
 148 static void ctdl_thread_internal_dest_tsd(void *arg)
 149 {
 150         if (arg != NULL) {
 151                 check_handles(arg);
 152                 free(arg);
 153         }
 154 }
 155
 156
 157 /*
 158  * A function to initialise the thread TSD
 159  */
 160 void ctdl_thread_internal_init_tsd(void)
 161 {
 162         int ret;
 163
 164         if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
 165                 CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
 166                 exit(CTDLEXIT_DB);
 167         }
 168 }
 169
 170 /*
 171  * Ensure that we have a key for thread-specific data.
 172  *
 173  * This should be called immediately after startup by any thread
 174  *
 175  */
 176 void CtdlThreadAllocTSD(void)
 177 {
 178         ThreadTSD *tsd;
 179
 180         if (citthread_getspecific(ThreadKey) != NULL)
 181                 return;
 182
 183         tsd = malloc(sizeof(ThreadTSD));
 184
 185         tsd->tid = NULL;
 186
 187         memset(tsd->cursors, 0, sizeof tsd->cursors);
 188         tsd->self = NULL;
 189
 190         citthread_setspecific(ThreadKey, tsd);
 191 }
 192
 193
 194 void ctdl_thread_internal_free_tsd(void)
 195 {
 196         ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
 197         citthread_setspecific(ThreadKey, NULL);
 198 }
 199
 200
 201 void ctdl_thread_internal_cleanup(void)
 202 {
 203         int i;
 204         CtdlThreadNode *this_thread, *that_thread;
 205
 206         for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
 207         {
 208                 free (CtdlThreadStates[i]);
 209         }
 210
 211         /* Clean up the scheduled thread list */
 212         this_thread = CtdlThreadSchedList;
 213         while (this_thread)
 214         {
 215                 that_thread = this_thread;
 216                 this_thread = this_thread->next;
 217                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 218                 citthread_cond_destroy(&that_thread->ThreadCond);
 219                 citthread_mutex_destroy(&that_thread->SleepMutex);
 220                 citthread_cond_destroy(&that_thread->SleepCond);
 221                 citthread_attr_destroy(&that_thread->attr);
 222                 free(that_thread);
 223         }
 224         ctdl_thread_internal_free_tsd();
 225 }
 226
 227 void ctdl_thread_internal_init(void)
 228 {
 229         CtdlThreadNode *this_thread;
 230         int ret = 0;
 231
 232         CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
 233         CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
 234         CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
 235         CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
 236         CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
 237         CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
 238         CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
 239         CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
 240         CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
 241         CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
 242
 243         /* Get ourself a thread entry */
 244         this_thread = malloc(sizeof(CtdlThreadNode));
 245         if (this_thread == NULL) {
 246                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 247                 return;
 248         }
 249         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 250         memset (this_thread, 0, sizeof(CtdlThreadNode));
 251
 252         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 253         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 254         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 255         citthread_cond_init (&(this_thread->SleepCond), NULL);
 256
 257         /* We are garbage collector so create us as running */
 258         this_thread->state = CTDL_THREAD_RUNNING;
 259
 260         if ((ret = citthread_attr_init(&this_thread->attr))) {
 261                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 262                 free(this_thread);
 263                 return;
 264         }
 265
 266         this_thread->name = "Garbage Collection Thread";
 267
 268         this_thread->tid = citthread_self();
 269         GC_thread = this_thread;
 270         CT = this_thread;
 271
 272         num_threads++;  // Increase the count of threads in the system.
 273
 274         this_thread->next = CtdlThreadList;
 275         CtdlThreadList = this_thread;
 276         if (this_thread->next)
 277                 this_thread->next->prev = this_thread;
 278         /* Set up start times */
 279         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 280         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 281 }
 282
 283
 284 /*
 285  * A function to update a threads load averages
 286  */
 287  void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
 288  {
 289         struct timeval now, result;
 290         double last_duration;
 291
 292         gettimeofday(&now, NULL);
 293         timersub(&now, &(this_thread->last_state_change), &result);
 294         /* I don't think these mutex's are needed here */
 295         citthread_mutex_lock(&this_thread->ThreadMutex);
 296         // result now has a timeval for the time we spent in the last state since we last updated
 297         last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
 298         if (this_thread->state == CTDL_THREAD_SLEEPING)
 299                 this_thread->avg_sleeping += last_duration;
 300         if (this_thread->state == CTDL_THREAD_RUNNING)
 301                 this_thread->avg_running += last_duration;
 302         if (this_thread->state == CTDL_THREAD_BLOCKED)
 303                 this_thread->avg_blocked += last_duration;
 304         memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
 305         citthread_mutex_unlock(&this_thread->ThreadMutex);
 306 }
 307
 308 /*
 309  * A function to chenge the state of a thread
 310  */
 311 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
 312 {
 313         /*
 314          * Wether we change state or not we need update the load values
 315          */
 316         ctdl_thread_internal_update_avgs(this_thread);
 317         /* This mutex not needed here? */
 318         citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
 319         if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
 320                 this_thread->state = new_state;
 321         if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
 322                 this_thread->state = new_state;
 323         if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
 324                 this_thread->state = new_state;
 325         citthread_mutex_unlock(&this_thread->ThreadMutex);
 326 }
 327
 328
 329 /*
 330  * A function to tell all threads to exit
 331  */
 332 void CtdlThreadStopAll(void)
 333 {
 334         /* First run any registered shutdown hooks.  This probably doesn't belong here. */
 335         PerformSessionHooks(EVT_SHUTDOWN);
 336
 337         //FIXME: The signalling of the condition should not be in the critical_section
 338         // We need to build a list of threads we are going to signal and then signal them afterwards
 339
 340         CtdlThreadNode *this_thread;
 341
 342         begin_critical_section(S_THREAD_LIST);
 343         this_thread = CtdlThreadList;
 344         // Ask the GC thread to stop first so everything knows we are shutting down.
 345         GC_thread->state = CTDL_THREAD_STOP_REQ;
 346         while(this_thread)
 347         {
 348 #ifdef THREADS_USESIGNALS
 349                 if (!citthread_equal(this_thread->tid, GC_thread->tid))
 350                         citthread_kill(this_thread->tid, SIGHUP);
 351 #endif
 352                 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 353                 citthread_cond_signal(&this_thread->ThreadCond);
 354                 citthread_cond_signal(&this_thread->SleepCond);
 355                 this_thread->stop_ticker = time(NULL);
 356                 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
 357                         this_thread->name, this_thread->tid);
 358                 this_thread = this_thread->next;
 359         }
 360         end_critical_section(S_THREAD_LIST);
 361 }
 362
 363
 364 /*
 365  * A function to wake up all sleeping threads
 366  */
 367 void CtdlThreadWakeAll(void)
 368 {
 369         CtdlThreadNode *this_thread;
 370
 371         CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
 372
 373         begin_critical_section(S_THREAD_LIST);
 374         this_thread = CtdlThreadList;
 375         while(this_thread)
 376         {
 377                 if (!this_thread->thread_func)
 378                 {
 379                         citthread_cond_signal(&this_thread->ThreadCond);
 380                         citthread_cond_signal(&this_thread->SleepCond);
 381                 }
 382                 this_thread = this_thread->next;
 383         }
 384         end_critical_section(S_THREAD_LIST);
 385 }
 386
 387
 388 /*
 389  * A function to return the number of threads running in the system
 390  */
 391 int CtdlThreadGetCount(void)
 392 {
 393         return  num_threads;
 394 }
 395
 396 int CtdlThreadGetWorkers(void)
 397 {
 398         return  num_workers;
 399 }
 400
 401 double CtdlThreadGetWorkerAvg(void)
 402 {
 403         double ret;
 404
 405         begin_critical_section(S_THREAD_LIST);
 406         ret =  CtdlThreadWorkerAvg;
 407         end_critical_section(S_THREAD_LIST);
 408         return ret;
 409 }
 410
 411 double CtdlThreadGetLoadAvg(void)
 412 {
 413         double load_avg[3] = {0.0, 0.0, 0.0};
 414
 415         int ret = 0;
 416         int smp_num_cpus;
 417
 418         /* Borrowed this straight from procps */
 419         smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 420         if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
 421
 422 #ifdef HAVE_GETLOADAVG
 423         ret = getloadavg(load_avg, 3);
 424 #endif
 425         if (ret < 0)
 426                 return 0;
 427         return load_avg[0] / smp_num_cpus;
 428 /*
 429  * This old chunk of code return a value that indicated the load on citserver
 430  * This value could easily reach 100 % even when citserver was doing very little and
 431  * hence the machine has much more spare capacity.
 432  * Because this value was used to determine if the machine was under heavy load conditions
 433  * from other processes in the system then citserver could be strangled un-necesarily
 434  * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
 435  * So we have changed this.
 436
 437         begin_critical_section(S_THREAD_LIST);
 438         ret =  CtdlThreadLoadAvg;
 439         end_critical_section(S_THREAD_LIST);
 440         return ret;
 441 */
 442 }
 443
 444
 445
 446
 447 /*
 448  * A function to rename a thread
 449  * Returns a const char *
 450  */
 451 const char *CtdlThreadName(const char *name)
 452 {
 453         const char *old_name;
 454
 455         if (!CT)
 456         {
 457                 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
 458                 return NULL;
 459         }
 460         old_name = CT->name;
 461         if (name)
 462                 CT->name = name;
 463         return (old_name);
 464 }
 465
 466
 467 /*
 468  * A function to force a thread to exit
 469  */
 470 void CtdlThreadCancel(CtdlThreadNode *thread)
 471 {
 472         CtdlThreadNode *this_thread;
 473
 474         if (!thread)
 475                 this_thread = CT;
 476         else
 477                 this_thread = thread;
 478         if (!this_thread)
 479         {
 480                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
 481                 CtdlThreadStopAll();
 482                 return;
 483         }
 484
 485         if (!this_thread->thread_func)
 486         {
 487                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
 488                 CtdlThreadStopAll();
 489                 return;
 490         }
 491
 492         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
 493         citthread_cancel(this_thread->tid);
 494 }
 495
 496
 497 /*
 498  * A function for a thread to check if it has been asked to stop
 499  */
 500 int CtdlThreadCheckStop(void)
 501 {
 502         int state;
 503
 504         if (!CT)
 505         {
 506                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
 507                 CtdlThreadStopAll();
 508                 return -1;
 509         }
 510
 511         state = CT->state;
 512
 513 #ifdef THREADS_USESIGNALS
 514         if (CT->signal)
 515         {
 516                 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
 517                 CT->signal = 0;
 518         }
 519 #endif
 520         if(state == CTDL_THREAD_STOP_REQ)
 521         {
 522                 CT->state = CTDL_THREAD_STOPPING;
 523                 return -1;
 524         }
 525         else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
 526         {
 527                 return -1;
 528         }
 529         return 0;
 530 }
 531
 532
 533 /*
 534  * A function to ask a thread to exit
 535  * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
 536  */
 537 void CtdlThreadStop(CtdlThreadNode *thread)
 538 {
 539         CtdlThreadNode *this_thread;
 540
 541         if (!thread)
 542                 this_thread = CT;
 543         else
 544                 this_thread = thread;
 545         if (!this_thread)
 546                 return;
 547         if (!(this_thread->thread_func))
 548                 return;         // Don't stop garbage collector
 549 #ifdef THREADS_USESIGNALS
 550         if (!citthread_equal(this_thread->tid, GC_thread->tid))
 551                 citthread_kill(this_thread->tid, SIGHUP);
 552 #endif
 553         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 554         citthread_cond_signal(&this_thread->ThreadCond);
 555         citthread_cond_signal(&this_thread->SleepCond);
 556         this_thread->stop_ticker = time(NULL);
 557 }
 558
 559 /*
 560  * So we now have a sleep command that works with threads but it is in seconds
 561  */
 562 void CtdlThreadSleep(int secs)
 563 {
 564         struct timespec wake_time;
 565         struct timeval time_now;
 566
 567
 568         if (!CT)
 569         {
 570                 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
 571                 return;
 572         }
 573
 574         memset (&wake_time, 0, sizeof(struct timespec));
 575         gettimeofday(&time_now, NULL);
 576         wake_time.tv_sec = time_now.tv_sec + secs;
 577         wake_time.tv_nsec = time_now.tv_usec * 10;
 578
 579         ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
 580
 581         citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
 582         citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
 583         citthread_mutex_unlock(&CT->ThreadMutex);
 584
 585         ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 586 }
 587
 588
 589 /*
 590  * Routine to clean up our thread function on exit
 591  */
 592 static void ctdl_internal_thread_cleanup(void *arg)
 593 {
 594         /*
 595          * In here we were called by the current thread because it is exiting
 596          * NB. WE ARE THE CURRENT THREAD
 597          */
 598         CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", CT->name, CT->tid);
 599
 600         #ifdef HAVE_BACKTRACE
 601         eCrash_UnregisterThread();
 602         #endif
 603
 604         citthread_mutex_lock(&CT->ThreadMutex);
 605         CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
 606         citthread_mutex_unlock(&CT->ThreadMutex);
 607 }
 608
 609 /*
 610  * A quick function to show the load averages
 611  */
 612 void ctdl_thread_internal_calc_loadavg(void)
 613 {
 614         CtdlThreadNode *that_thread;
 615         double load_avg, worker_avg;
 616         int workers = 0;
 617
 618         that_thread = CtdlThreadList;
 619         load_avg = 0;
 620         worker_avg = 0;
 621         while(that_thread)
 622         {
 623                 /* Update load averages */
 624                 ctdl_thread_internal_update_avgs(that_thread);
 625                 citthread_mutex_lock(&that_thread->ThreadMutex);
 626                 that_thread->load_avg = (that_thread->avg_sleeping + that_thread->avg_running) / (that_thread->avg_sleeping + that_thread->avg_running + that_thread->avg_blocked) * 100;
 627                 that_thread->avg_sleeping /= 2;
 628                 that_thread->avg_running /= 2;
 629                 that_thread->avg_blocked /= 2;
 630                 load_avg += that_thread->load_avg;
 631                 if (that_thread->flags & CTDLTHREAD_WORKER)
 632                 {
 633                         worker_avg += that_thread->load_avg;
 634                         workers++;
 635                 }
 636 #ifdef WITH_THREADLOG
 637                 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
 638                         that_thread->name,
 639                         that_thread->tid,
 640                         CtdlThreadStates[that_thread->state],
 641                         that_thread->avg_sleeping,
 642                         that_thread->avg_running,
 643                         that_thread->avg_blocked,
 644                         that_thread->load_avg);
 645 #endif
 646                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 647                 that_thread = that_thread->next;
 648         }
 649         CtdlThreadLoadAvg = load_avg/num_threads;
 650         CtdlThreadWorkerAvg = worker_avg/workers;
 651 #ifdef WITH_THREADLOG
 652         CtdlLogPrintf(CTDL_INFO, "System load average %.2f, workers averag %.2f, threads %d, workers %d, sessions %d\n", CtdlThreadGetLoadAvg(), CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
 653 #endif
 654 }
 655
 656
 657 /*
 658  * Garbage collection routine.
 659  * Gets called by main() in a loop to clean up the thread list periodically.
 660  */
 661 void CtdlThreadGC (void)
 662 {
 663         CtdlThreadNode *this_thread, *that_thread;
 664         int workers = 0, sys_workers;
 665         int ret=0;
 666
 667         begin_critical_section(S_THREAD_LIST);
 668
 669         /* Handle exiting of garbage collector thread */
 670         if(num_threads == 1)
 671                 CtdlThreadList->state = CTDL_THREAD_EXITED;
 672
 673 #ifdef WITH_THREADLOG
 674         CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
 675 #endif
 676         /*
 677          * Woke up to do garbage collection
 678          */
 679         this_thread = CtdlThreadList;
 680         while(this_thread)
 681         {
 682                 that_thread = this_thread;
 683                 this_thread = this_thread->next;
 684
 685                 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
 686                         && (!citthread_equal(that_thread->tid, citthread_self())))
 687                                 CtdlLogPrintf(CTDL_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
 688                 else
 689                 {
 690                         /**
 691                          * Catch the situation where a worker was asked to stop but couldn't and we are not
 692                          * shutting down.
 693                          */
 694                         that_thread->stop_ticker = 0;
 695                 }
 696
 697                 if (that_thread->stop_ticker + 5 == time(NULL))
 698                 {
 699                         CtdlLogPrintf(CTDL_DEBUG, "Thread System: The thread \"%s\" (0x%08lx) failed to self terminate within 5 ticks. It would be cancelled now.\n", that_thread->name, that_thread->tid);
 700                         if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
 701                                 CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
 702 //                      that_thread->state = CTDL_THREAD_CANCELLED;
 703                         that_thread->stop_ticker++;
 704 //                      citthread_cancel(that_thread->tid);
 705 //                      continue;
 706                 }
 707
 708                 /* Do we need to clean up this thread? */
 709                 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
 710                 {
 711                         if(that_thread->flags & CTDLTHREAD_WORKER)
 712                                 workers++;      /* Sanity check on number of worker threads */
 713                         continue;
 714                 }
 715
 716                 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
 717                 {       /* Sanity check */
 718                         end_critical_section(S_THREAD_LIST);
 719                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
 720                         abort();
 721                         return;
 722                 }
 723
 724                 if (num_threads <= 0)
 725                 {       /* Sanity check */
 726                         end_critical_section(S_THREAD_LIST);
 727                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
 728                         abort();
 729                         return;
 730                 }
 731
 732                 if(that_thread->flags & CTDLTHREAD_WORKER)
 733                         num_workers--;  /* This is a wroker thread so reduce the count. */
 734                 num_threads--;
 735                 /* If we are unlinking the list head then the next becomes the list head */
 736                 if(that_thread->prev)
 737                         that_thread->prev->next = that_thread->next;
 738                 else
 739                         CtdlThreadList = that_thread->next;
 740                 if(that_thread->next)
 741                         that_thread->next->prev = that_thread->prev;
 742
 743                 citthread_cond_signal(&that_thread->ThreadCond);
 744                 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
 745                 citthread_mutex_lock(&that_thread->ThreadMutex);        // Make sure it has done what its doing
 746                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 747                 /*
 748                  * Join on the thread to do clean up and prevent memory leaks
 749                  * Also makes sure the thread has cleaned up after itself before we remove it from the list
 750                  * We can join on the garbage collector thread the join should just return EDEADLCK
 751                  */
 752                 ret = citthread_join (that_thread->tid, NULL);
 753                 if (ret == EDEADLK)
 754                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
 755                 else if (ret == EINVAL)
 756                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
 757                 else if (ret == ESRCH)
 758                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
 759                 else if (ret != 0)
 760                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
 761                 /*
 762                  * Now we own that thread entry
 763                  */
 764                 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
 765                         that_thread->name, that_thread->tid);
 766                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 767                 citthread_cond_destroy(&that_thread->ThreadCond);
 768                 citthread_mutex_destroy(&that_thread->SleepMutex);
 769                 citthread_cond_destroy(&that_thread->SleepCond);
 770                 citthread_attr_destroy(&that_thread->attr);
 771                 free(that_thread);
 772         }
 773         sys_workers = num_workers;
 774         end_critical_section(S_THREAD_LIST);
 775
 776         /* Sanity check number of worker threads */
 777         if (workers != sys_workers)
 778         {
 779                 CtdlLogPrintf(CTDL_EMERG,
 780                         "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
 781                         workers, sys_workers
 782                         );
 783                 abort();
 784         }
 785 }
 786
 787
 788
 789
 790 /*
 791  * Runtime function for a Citadel Thread.
 792  * This initialises the threads environment and then calls the user supplied thread function
 793  * Note that this is the REAL thread function and wraps the users thread function.
 794  */
 795 static void *ctdl_internal_thread_func (void *arg)
 796 {
 797         CtdlThreadNode *this_thread;
 798         void *ret = NULL;
 799
 800         /* lock and unlock the thread list.
 801          * This causes this thread to wait until all its creation stuff has finished before it
 802          * can continue its execution.
 803          */
 804         begin_critical_section(S_THREAD_LIST);
 805         this_thread = (CtdlThreadNode *) arg;
 806         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 807
 808         // Register the cleanup function to take care of when we exit.
 809         citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
 810         // Get our thread data structure
 811         CtdlThreadAllocTSD();
 812         CT = this_thread;
 813         this_thread->pid = getpid();
 814         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 815         /* Only change to running state if we weren't asked to stop during the create cycle
 816          * Other wise there is a window to allow this threads creation to continue to full grown and
 817          * therby prevent a shutdown of the server.
 818          */
 819         if (!CtdlThreadCheckStop())
 820         {
 821                 citthread_mutex_lock(&this_thread->ThreadMutex);
 822                 this_thread->state = CTDL_THREAD_RUNNING;
 823                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 824         }
 825         end_critical_section(S_THREAD_LIST);
 826
 827         // Register for tracing
 828         #ifdef HAVE_BACKTRACE
 829         eCrash_RegisterThread(this_thread->name, 0);
 830         #endif
 831
 832         // Tell the world we are here
 833         CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
 834                 this_thread->name, this_thread->tid);
 835
 836         /*
 837          * run the thread to do the work but only if we haven't been asked to stop
 838          */
 839         if (!CtdlThreadCheckStop())
 840                 ret = (this_thread->thread_func)(this_thread->user_args);
 841
 842         /*
 843          * Our thread is exiting either because it wanted to end or because the server is stopping
 844          * We need to clean up
 845          */
 846         citthread_cleanup_pop(1);       // Execute our cleanup routine and remove it
 847
 848         return(ret);
 849 }
 850
 851
 852
 853
 854 /*
 855  * Function to initialise an empty thread structure
 856  */
 857 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
 858 {
 859         int ret = 0;
 860
 861         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 862         memset (this_thread, 0, sizeof(CtdlThreadNode));
 863
 864         /* Create the mutex's early so we can use them */
 865         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 866         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 867         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 868         citthread_cond_init (&(this_thread->SleepCond), NULL);
 869
 870         this_thread->state = CTDL_THREAD_CREATE;
 871
 872         if ((ret = citthread_attr_init(&this_thread->attr))) {
 873                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 874                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 875                 citthread_cond_destroy(&(this_thread->ThreadCond));
 876                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 877                 citthread_cond_destroy(&(this_thread->SleepCond));
 878                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 879                 free(this_thread);
 880                 return NULL;
 881         }
 882
 883         /* Our per-thread stacks need to be bigger than the default size,
 884          * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
 885          * crashes on 64-bit Linux.
 886          */
 887         if (flags & CTDLTHREAD_BIGSTACK)
 888         {
 889 #ifdef WITH_THREADLOG
 890                 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
 891 #endif
 892                 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
 893                         citthread_mutex_unlock(&this_thread->ThreadMutex);
 894                         citthread_mutex_destroy(&(this_thread->ThreadMutex));
 895                         citthread_cond_destroy(&(this_thread->ThreadCond));
 896                         citthread_mutex_destroy(&(this_thread->SleepMutex));
 897                         citthread_cond_destroy(&(this_thread->SleepCond));
 898                         citthread_attr_destroy(&this_thread->attr);
 899                         CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
 900                                 strerror(ret));
 901                         free(this_thread);
 902                         return NULL;
 903                 }
 904         }
 905
 906         /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
 907          * load average for the system. If we don't do this then we create a mass of threads at the same time
 908          * because the creation didn't affect the load average.
 909          */
 910         this_thread->avg_blocked = 2;
 911
 912         return (this_thread);
 913 }
 914
 915
 916
 917
 918 /*
 919  * Internal function to create a thread.
 920  */
 921 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 922 {
 923         int ret = 0;
 924         CtdlThreadNode *this_thread;
 925
 926         if (num_threads >= 32767)
 927         {
 928                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 929                 return NULL;
 930         }
 931
 932         this_thread = malloc(sizeof(CtdlThreadNode));
 933         if (this_thread == NULL) {
 934                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 935                 return NULL;
 936         }
 937
 938         /* Initialise the thread structure */
 939         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
 940         {
 941                 free(this_thread);
 942                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
 943                 return NULL;
 944         }
 945         /*
 946          * If we got here we are going to create the thread so we must initilise the structure
 947          * first because most implimentations of threading can't create it in a stopped state
 948          * and it might want to do things with its structure that aren't initialised otherwise.
 949          */
 950         if(name)
 951         {
 952                 this_thread->name = name;
 953         }
 954         else
 955         {
 956                 this_thread->name = "Un-named Thread";
 957         }
 958
 959         this_thread->flags = flags;
 960         this_thread->thread_func = thread_func;
 961         this_thread->user_args = args;
 962
 963         begin_critical_section(S_THREAD_LIST);
 964         /*
 965          * We pass this_thread into the thread as its args so that it can find out information
 966          * about itself and it has a bit of storage space for itself, not to mention that the REAL
 967          * thread function needs to finish off the setup of the structure
 968          */
 969         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
 970         {
 971                 end_critical_section(S_THREAD_LIST);
 972                 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
 973                         strerror(ret));
 974                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 975                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 976                 citthread_cond_destroy(&(this_thread->ThreadCond));
 977                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 978                 citthread_cond_destroy(&(this_thread->SleepCond));
 979                 citthread_attr_destroy(&this_thread->attr);
 980                 free(this_thread);
 981                 return NULL;
 982         }
 983
 984         num_threads++;  // Increase the count of threads in the system.
 985         if(this_thread->flags & CTDLTHREAD_WORKER)
 986                 num_workers++;
 987
 988         this_thread->next = CtdlThreadList;
 989         CtdlThreadList = this_thread;
 990         if (this_thread->next)
 991                 this_thread->next->prev = this_thread;
 992         ctdl_thread_internal_calc_loadavg();
 993
 994         end_critical_section(S_THREAD_LIST);
 995
 996         return this_thread;
 997 }
 998
 999 /*
1000  * Wrapper function to create a thread
1001  * ensures the critical section and other protections are in place.
1002  * char *name = name to give to thread, if NULL, use generic name
1003  * int flags = flags to determine type of thread and standard facilities
1004  */
1005 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
1006 {
1007         CtdlThreadNode *ret = NULL;
1008
1009         ret = ctdl_internal_create_thread(name, flags, thread_func, args);
1010         return ret;
1011 }
1012
1013
1014
1015 /*
1016  * Internal function to schedule a thread.
1017  * Must be called from within a S_THREAD_LIST critical section
1018  */
1019 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
1020 {
1021         CtdlThreadNode *this_thread;
1022
1023         if (num_threads >= 32767)
1024         {
1025                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
1026                 return NULL;
1027         }
1028
1029         this_thread = malloc(sizeof(CtdlThreadNode));
1030         if (this_thread == NULL) {
1031                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
1032                 return NULL;
1033         }
1034         /* Initialise the thread structure */
1035         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
1036         {
1037                 free(this_thread);
1038                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
1039                 return NULL;
1040         }
1041
1042         /*
1043          * If we got here we are going to create the thread so we must initilise the structure
1044          * first because most implimentations of threading can't create it in a stopped state
1045          * and it might want to do things with its structure that aren't initialised otherwise.
1046          */
1047         if(name)
1048         {
1049                 this_thread->name = name;
1050         }
1051         else
1052         {
1053                 this_thread->name = "Un-named Thread";
1054         }
1055
1056         this_thread->flags = flags;
1057         this_thread->thread_func = thread_func;
1058         this_thread->user_args = args;
1059
1060         /*
1061          * When to start this thread
1062          */
1063         this_thread->when = when;
1064
1065         begin_critical_section(S_SCHEDULE_LIST);
1066         this_thread->next = CtdlThreadSchedList;
1067         CtdlThreadSchedList = this_thread;
1068         if (this_thread->next)
1069                 this_thread->next->prev = this_thread;
1070         end_critical_section(S_SCHEDULE_LIST);
1071
1072         return this_thread;
1073 }
1074
1075
1076
1077 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1078 {
1079         int ret = 0;
1080
1081         begin_critical_section(S_THREAD_LIST);
1082         /*
1083          * We pass this_thread into the thread as its args so that it can find out information
1084          * about itself and it has a bit of storage space for itself, not to mention that the REAL
1085          * thread function needs to finish off the setup of the structure
1086          */
1087         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1088         {
1089                 end_critical_section(S_THREAD_LIST);
1090                 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1091                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1092                 citthread_cond_destroy(&(this_thread->ThreadCond));
1093                 citthread_mutex_destroy(&(this_thread->SleepMutex));
1094                 citthread_cond_destroy(&(this_thread->SleepCond));
1095                 citthread_attr_destroy(&this_thread->attr);
1096                 free(this_thread);
1097                 return NULL;
1098         }
1099
1100
1101         num_threads++;  // Increase the count of threads in the system.
1102         if(this_thread->flags & CTDLTHREAD_WORKER)
1103                 num_workers++;
1104
1105         this_thread->next = CtdlThreadList;
1106         CtdlThreadList = this_thread;
1107         if (this_thread->next)
1108                 this_thread->next->prev = this_thread;
1109
1110         ctdl_thread_internal_calc_loadavg();
1111         end_critical_section(S_THREAD_LIST);
1112
1113
1114         return this_thread;
1115 }
1116
1117
1118
1119 void ctdl_thread_internal_check_scheduled(void)
1120 {
1121         CtdlThreadNode *this_thread, *that_thread;
1122         time_t now;
1123
1124         /* Don't start scheduled threads if the system wants single user mode */
1125         if (CtdlWantSingleUser())
1126                 return;
1127
1128         if (try_critical_section(S_SCHEDULE_LIST))
1129                 return; /* If this list is locked we wait till the next chance */
1130
1131         now = time(NULL);
1132
1133 #ifdef WITH_THREADLOG
1134         CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1135 #endif
1136
1137         this_thread = CtdlThreadSchedList;
1138         while(this_thread)
1139         {
1140                 that_thread = this_thread;
1141                 this_thread = this_thread->next;
1142
1143                 if (now > that_thread->when)
1144                 {
1145                         /* Unlink from schedule list */
1146                         if (that_thread->prev)
1147                                 that_thread->prev->next = that_thread->next;
1148                         else
1149                                 CtdlThreadSchedList = that_thread->next;
1150                         if (that_thread->next)
1151                                 that_thread->next->prev = that_thread->prev;
1152
1153                         that_thread->next = that_thread->prev = NULL;
1154 #ifdef WITH_THREADLOG
1155                         CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1156 #endif
1157                         if (CT->state > CTDL_THREAD_STOP_REQ)
1158                         {       /* Only start it if the system is not stopping */
1159                                 if (ctdl_thread_internal_start_scheduled (that_thread))
1160                                 {
1161 #ifdef WITH_THREADLOG
1162                                         CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
1163                                                 that_thread->name, that_thread->tid);
1164 #endif
1165                                 }
1166                         }
1167                 }
1168 #ifdef WITH_THREADLOG
1169                 else
1170                 {
1171                         CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1172                                 that_thread->name, that_thread->when - time(NULL));
1173                 }
1174 #endif
1175         }
1176         end_critical_section(S_SCHEDULE_LIST);
1177 }
1178
1179
1180 /*
1181  * A warapper function for select so we can show a thread as blocked
1182  */
1183 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1184 {
1185         int ret = 0;
1186
1187         ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1188         if (!CtdlThreadCheckStop())
1189                 ret = select(n, readfds, writefds, exceptfds, timeout);
1190         /**
1191          * If the select returned <= 0 then it failed due to an error
1192          * or timeout so this thread could stop if asked to do so.
1193          * Anything else means it needs to continue unless the system is shutting down
1194          */
1195         if (ret > 0)
1196         {
1197                 /**
1198                  * The select says this thread needs to do something useful.
1199                  * This thread was in an idle state so it may have been asked to stop
1200                  * but if the system isn't shutting down this thread is no longer
1201                  * idle and select has given it a task to do so it must not stop
1202                  * In this condition we need to force it into the running state.
1203                  * CtdlThreadGC will clear its ticker for us.
1204                  *
1205                  * FIXME: there is still a small hole here. It is possible for the sequence of locking
1206                  * to allow the state to get changed to STOP_REQ just after this code if the other thread
1207                  * has decided to change the state before this lock, it there fore has to wait till the lock
1208                  * completes but it will continue to change the state. We need something a bit better here.
1209                  */
1210                 citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1211                 if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
1212                 {
1213                         CtdlLogPrintf(CTDL_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
1214                         CT->state = CTDL_THREAD_RUNNING;
1215                 }
1216                 citthread_mutex_unlock(&CT->ThreadMutex);
1217         }
1218
1219         ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1220
1221         return ret;
1222 }
1223
1224
1225
1226 void *new_worker_thread(void *arg);
1227 extern void close_masters (void);
1228
1229
1230 void *simulation_worker (void*arg) {
1231         struct CitContext *this;
1232
1233         this = CreateNewContext();
1234         CtdlThreadSleep(1);
1235         this->kill_me = 1;
1236         this->state = CON_IDLE;
1237         dead_session_purge(1);
1238         begin_critical_section(S_SESSION_TABLE);
1239         stats_done++;
1240         end_critical_section(S_SESSION_TABLE);
1241         return NULL;
1242 }
1243
1244
1245 void *simulation_thread (void *arg)
1246 {
1247         long stats = statcount;
1248
1249         while(stats && !CtdlThreadCheckStop()) {
1250                 CtdlThreadCreate("Connection simulation worker", CTDLTHREAD_BIGSTACK, simulation_worker, NULL);
1251                 stats--;
1252         }
1253         CtdlThreadStopAll();
1254         return NULL;
1255 }
1256
1257 void go_threading(void)
1258 {
1259         int i;
1260         CtdlThreadNode *last_worker;
1261         struct timeval start, now, result;
1262         double last_duration;
1263
1264         /*
1265          * Initialise the thread system
1266          */
1267         ctdl_thread_internal_init();
1268
1269         /* Second call to module init functions now that threading is up */
1270         if (!statcount)
1271                 initialise_modules(1);
1272         else {
1273                 CtdlLogPrintf(CTDL_EMERG, "Running connection simulation stats\n");
1274                 gettimeofday(&start, NULL);
1275                 CtdlThreadCreate("Connection simulation master", CTDLTHREAD_BIGSTACK, simulation_thread, NULL);
1276         }
1277
1278
1279         /*
1280          * This thread is now used for garbage collection of other threads in the thread list
1281          */
1282         CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1283
1284         /*
1285          * We do a lot of locking and unlocking of the thread list in here.
1286          * We do this so that we can repeatedly release time for other threads
1287          * that may be waiting on the thread list.
1288          * We are a low priority thread so we can afford to do this
1289          */
1290
1291         while (CtdlThreadGetCount())
1292         {
1293                 if (CT->signal)
1294                         exit_signal = CT->signal;
1295                 if (exit_signal)
1296                 {
1297                         CtdlThreadStopAll();
1298                 }
1299                 check_sched_shutdown();
1300                 if (CT->state > CTDL_THREAD_STOP_REQ)
1301                 {
1302                         begin_critical_section(S_THREAD_LIST);
1303                         ctdl_thread_internal_calc_loadavg();
1304                         end_critical_section(S_THREAD_LIST);
1305
1306                         ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1307                 }
1308
1309                 /* Reduce the size of the worker thread pool if necessary. */
1310                 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1311                 {
1312                         /* Ask a worker thread to stop as we no longer need it */
1313                         begin_critical_section(S_THREAD_LIST);
1314                         last_worker = CtdlThreadList;
1315                         while (last_worker)
1316                         {
1317                                 citthread_mutex_lock(&last_worker->ThreadMutex);
1318                                 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1319                                 {
1320                                         citthread_mutex_unlock(&last_worker->ThreadMutex);
1321                                         break;
1322                                 }
1323                                 citthread_mutex_unlock(&last_worker->ThreadMutex);
1324                                 last_worker = last_worker->next;
1325                         }
1326                         end_critical_section(S_THREAD_LIST);
1327                         if (last_worker)
1328                         {
1329 #ifdef WITH_THREADLOG
1330                                 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1331                                         last_worker->name,
1332                                         last_worker->tid
1333                                         );
1334 #endif
1335                                 CtdlThreadStop(last_worker);
1336                         }
1337                 }
1338
1339                 /*
1340                  * If all our workers are working hard, start some more to help out
1341                  * with things
1342                  */
1343                 /* FIXME: come up with a better way to dynamically alter the number of threads
1344                  * based on the system load
1345                  */
1346                 if (!statcount) {
1347                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60)) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1348                 {
1349                         /* Only start new threads if we are not going to overload the machine */
1350                         /* Temporarily set to 10 should be enough to make sure we don't stranglew the server
1351                          * at least until we make this a config option */
1352                         if (CtdlThreadGetLoadAvg() < ((double)10.00)) {
1353                                 for (i=0; i<5 ; i++) {
1354                                         CtdlThreadCreate("Worker Thread",
1355                                                 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1356                                                 worker_thread,
1357                                                 NULL
1358                                                 );
1359                                 }
1360                         }
1361                         else
1362                                 CtdlLogPrintf (CTDL_WARNING, "Server strangled due to machine load average too high.\n");
1363                 }
1364                 }
1365
1366                 CtdlThreadGC();
1367
1368                 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1369                 {
1370                         CtdlThreadGC();
1371                 }
1372
1373 #ifdef THREADS_USESIGNALS
1374                 if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
1375 #else
1376                 if (CtdlThreadGetCount())
1377 #endif
1378                         CtdlThreadSleep(1);
1379         }
1380         /*
1381          * If the above loop exits we must be shutting down since we obviously have no threads
1382          */
1383         ctdl_thread_internal_cleanup();
1384
1385         if (statcount) {
1386                 gettimeofday(&now, NULL);
1387                 timersub(&now, &start, &result);
1388                 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
1389                 CtdlLogPrintf(CTDL_EMERG, "Simulated %ld connections in %f seconds\n", stats_done, last_duration);
1390         }
1391 }
1392
1393
1394
1395