citadel/threads.c

   1 /*
   2  * Thread handling stuff for Citadel server
   3  *
   4  * Copyright (c) 1987-2010 by the citadel.org team
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <stdio.h>
  24 #include <sys/types.h>
  25 #include <errno.h>
  26 #include <sys/socket.h>
  27 #include <unistd.h>
  28 #include <fcntl.h>
  29 #include <signal.h>
  30
  31 #include "sysdep.h"
  32 #if TIME_WITH_SYS_TIME
  33 # include <sys/time.h>
  34 # include <time.h>
  35 #else
  36 # if HAVE_SYS_TIME_H
  37 #  include <sys/time.h>
  38 # else
  39 #  include <time.h>
  40 # endif
  41 #endif
  42
  43 #ifdef HAVE_SYSCALL_H
  44 # include <syscall.h>
  45 #else
  46 # if HAVE_SYS_SYSCALL_H
  47 #  include <sys/syscall.h>
  48 # endif
  49 #endif
  50
  51 #include <libcitadel.h>
  52
  53 #include "threads.h"
  54 #include "ctdl_module.h"
  55 #include "modules_init.h"
  56 #include "housekeeping.h"
  57 #include "config.h"
  58 #include "citserver.h"
  59 #include "sysdep_decls.h"
  60 #include "context.h"
  61
  62 /*
  63  * define this to use the new worker_thread method of handling connections
  64  */
  65 //#define NEW_WORKER
  66
  67 /*
  68  * New thread interface.
  69  * To create a thread you must call one of the create thread functions.
  70  * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
  71  * struct CtdlThreadNode *node = NULL;
  72  * pass in &node
  73  * If the thread is created *node will point to the thread control structure for the created thread.
  74  * If the thread creation fails *node remains NULL
  75  * Do not free the memory pointed to by *node, it doesn't belong to you.
  76  * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
  77  * remove the need for the calls to eCrashRegisterThread and friends
  78  */
  79
  80 static int num_threads = 0;                     /* Current number of threads */
  81 static int num_workers = 0;                     /* Current number of worker threads */
  82 long statcount = 0;             /* are we doing a stats check? */
  83 static long stats_done = 0;
  84
  85 CtdlThreadNode *CtdlThreadList = NULL;
  86 CtdlThreadNode *CtdlThreadSchedList = NULL;
  87
  88 static CtdlThreadNode *GC_thread = NULL;
  89 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
  90 double CtdlThreadLoadAvg = 0;
  91 double CtdlThreadWorkerAvg = 0;
  92 citthread_key_t ThreadKey;
  93
  94 citthread_mutex_t Critters[MAX_SEMAPHORES];     /* Things needing locking */
  95
  96
  97
  98 void InitialiseSemaphores(void)
  99 {
 100         int i;
 101
 102         /* Set up a bunch of semaphores to be used for critical sections */
 103         for (i=0; i<MAX_SEMAPHORES; ++i) {
 104                 citthread_mutex_init(&Critters[i], NULL);
 105         }
 106 }
 107
 108
 109
 110
 111 /*
 112  * Obtain a semaphore lock to begin a critical section.
 113  * but only if no one else has one
 114  */
 115 int try_critical_section(int which_one)
 116 {
 117         /* For all types of critical sections except those listed here,
 118          * ensure nobody ever tries to do a critical section within a
 119          * transaction; this could lead to deadlock.
 120          */
 121         if (    (which_one != S_FLOORCACHE)
 122 #ifdef DEBUG_MEMORY_LEAKS
 123                 && (which_one != S_DEBUGMEMLEAKS)
 124 #endif
 125                 && (which_one != S_RPLIST)
 126         ) {
 127                 cdb_check_handles();
 128         }
 129         return (citthread_mutex_trylock(&Critters[which_one]));
 130 }
 131
 132
 133 /*
 134  * Obtain a semaphore lock to begin a critical section.
 135  */
 136 void begin_critical_section(int which_one)
 137 {
 138         /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
 139
 140         /* For all types of critical sections except those listed here,
 141          * ensure nobody ever tries to do a critical section within a
 142          * transaction; this could lead to deadlock.
 143          */
 144         if (    (which_one != S_FLOORCACHE)
 145 #ifdef DEBUG_MEMORY_LEAKS
 146                 && (which_one != S_DEBUGMEMLEAKS)
 147 #endif
 148                 && (which_one != S_RPLIST)
 149         ) {
 150                 cdb_check_handles();
 151         }
 152         citthread_mutex_lock(&Critters[which_one]);
 153 }
 154
 155 /*
 156  * Release a semaphore lock to end a critical section.
 157  */
 158 void end_critical_section(int which_one)
 159 {
 160         citthread_mutex_unlock(&Critters[which_one]);
 161 }
 162
 163
 164 /*
 165  * A function to destroy the TSD
 166  */
 167 static void ctdl_thread_internal_dest_tsd(void *arg)
 168 {
 169         if (arg != NULL) {
 170                 check_handles(arg);
 171                 free(arg);
 172         }
 173 }
 174
 175
 176 /*
 177  * A function to initialise the thread TSD
 178  */
 179 void ctdl_thread_internal_init_tsd(void)
 180 {
 181         int ret;
 182
 183         if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
 184                 CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
 185                 exit(CTDLEXIT_DB);
 186         }
 187 }
 188
 189 /*
 190  * Ensure that we have a key for thread-specific data.
 191  *
 192  * This should be called immediately after startup by any thread
 193  *
 194  */
 195 void CtdlThreadAllocTSD(void)
 196 {
 197         ThreadTSD *tsd;
 198
 199         if (citthread_getspecific(ThreadKey) != NULL)
 200                 return;
 201
 202         tsd = malloc(sizeof(ThreadTSD));
 203
 204         tsd->tid = NULL;
 205
 206         memset(tsd->cursors, 0, sizeof tsd->cursors);
 207         tsd->self = NULL;
 208
 209         citthread_setspecific(ThreadKey, tsd);
 210 }
 211
 212
 213 void ctdl_thread_internal_free_tsd(void)
 214 {
 215         ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
 216         citthread_setspecific(ThreadKey, NULL);
 217 }
 218
 219
 220 void ctdl_thread_internal_cleanup(void)
 221 {
 222         int i;
 223         CtdlThreadNode *this_thread, *that_thread;
 224
 225         for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
 226         {
 227                 free (CtdlThreadStates[i]);
 228         }
 229
 230         /* Clean up the scheduled thread list */
 231         this_thread = CtdlThreadSchedList;
 232         while (this_thread)
 233         {
 234                 that_thread = this_thread;
 235                 this_thread = this_thread->next;
 236                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 237                 citthread_cond_destroy(&that_thread->ThreadCond);
 238                 citthread_mutex_destroy(&that_thread->SleepMutex);
 239                 citthread_cond_destroy(&that_thread->SleepCond);
 240                 citthread_attr_destroy(&that_thread->attr);
 241                 free(that_thread);
 242         }
 243         ctdl_thread_internal_free_tsd();
 244 }
 245
 246 void ctdl_thread_internal_init(void)
 247 {
 248         CtdlThreadNode *this_thread;
 249         int ret = 0;
 250
 251         CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
 252         CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
 253         CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
 254         CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
 255         CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
 256         CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
 257         CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
 258         CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
 259         CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
 260         CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
 261
 262         /* Get ourself a thread entry */
 263         this_thread = malloc(sizeof(CtdlThreadNode));
 264         if (this_thread == NULL) {
 265                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 266                 return;
 267         }
 268         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 269         memset (this_thread, 0, sizeof(CtdlThreadNode));
 270
 271         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 272         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 273         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 274         citthread_cond_init (&(this_thread->SleepCond), NULL);
 275
 276         /* We are garbage collector so create us as running */
 277         this_thread->state = CTDL_THREAD_RUNNING;
 278
 279         if ((ret = citthread_attr_init(&this_thread->attr))) {
 280                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 281                 free(this_thread);
 282                 return;
 283         }
 284
 285         this_thread->name = "Garbage Collection Thread";
 286
 287         this_thread->tid = citthread_self();
 288         GC_thread = this_thread;
 289         CT = this_thread;
 290
 291         num_threads++;  // Increase the count of threads in the system.
 292
 293         this_thread->next = CtdlThreadList;
 294         CtdlThreadList = this_thread;
 295         if (this_thread->next)
 296                 this_thread->next->prev = this_thread;
 297         /* Set up start times */
 298         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 299         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 300 }
 301
 302
 303 /*
 304  * A function to update a threads load averages
 305  */
 306  void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
 307  {
 308         struct timeval now, result;
 309         double last_duration;
 310
 311         gettimeofday(&now, NULL);
 312         timersub(&now, &(this_thread->last_state_change), &result);
 313         /* I don't think these mutex's are needed here */
 314         citthread_mutex_lock(&this_thread->ThreadMutex);
 315         // result now has a timeval for the time we spent in the last state since we last updated
 316         last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
 317         if (this_thread->state == CTDL_THREAD_SLEEPING)
 318                 this_thread->avg_sleeping += last_duration;
 319         if (this_thread->state == CTDL_THREAD_RUNNING)
 320                 this_thread->avg_running += last_duration;
 321         if (this_thread->state == CTDL_THREAD_BLOCKED)
 322                 this_thread->avg_blocked += last_duration;
 323         memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
 324         citthread_mutex_unlock(&this_thread->ThreadMutex);
 325 }
 326
 327 /*
 328  * A function to chenge the state of a thread
 329  */
 330 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
 331 {
 332         /*
 333          * Wether we change state or not we need update the load values
 334          */
 335         ctdl_thread_internal_update_avgs(this_thread);
 336         /* This mutex not needed here? */
 337         citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
 338         if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
 339                 this_thread->state = new_state;
 340         if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
 341                 this_thread->state = new_state;
 342         if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
 343                 this_thread->state = new_state;
 344         citthread_mutex_unlock(&this_thread->ThreadMutex);
 345 }
 346
 347
 348 /*
 349  * A function to tell all threads to exit
 350  */
 351 void CtdlThreadStopAll(void)
 352 {
 353         /* First run any registered shutdown hooks.  This probably doesn't belong here. */
 354         PerformSessionHooks(EVT_SHUTDOWN);
 355
 356         /* then close all tcp ports so nobody else can talk to us anymore. */
 357         CtdlShutdownServiceHooks();
 358         //FIXME: The signalling of the condition should not be in the critical_section
 359         // We need to build a list of threads we are going to signal and then signal them afterwards
 360
 361         CtdlThreadNode *this_thread;
 362
 363         begin_critical_section(S_THREAD_LIST);
 364         this_thread = CtdlThreadList;
 365         // Ask the GC thread to stop first so everything knows we are shutting down.
 366         GC_thread->state = CTDL_THREAD_STOP_REQ;
 367         while(this_thread)
 368         {
 369                 if (!citthread_equal(this_thread->tid, GC_thread->tid))
 370                         citthread_kill(this_thread->tid, SIGHUP);
 371
 372                 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 373                 citthread_cond_signal(&this_thread->ThreadCond);
 374                 citthread_cond_signal(&this_thread->SleepCond);
 375                 this_thread->stop_ticker = time(NULL);
 376                 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
 377                         this_thread->name, this_thread->tid);
 378                 this_thread = this_thread->next;
 379         }
 380         end_critical_section(S_THREAD_LIST);
 381 }
 382
 383
 384 /*
 385  * A function to wake up all sleeping threads
 386  */
 387 void CtdlThreadWakeAll(void)
 388 {
 389         CtdlThreadNode *this_thread;
 390
 391         CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
 392
 393         begin_critical_section(S_THREAD_LIST);
 394         this_thread = CtdlThreadList;
 395         while(this_thread)
 396         {
 397                 if (!this_thread->thread_func)
 398                 {
 399                         citthread_cond_signal(&this_thread->ThreadCond);
 400                         citthread_cond_signal(&this_thread->SleepCond);
 401                 }
 402                 this_thread = this_thread->next;
 403         }
 404         end_critical_section(S_THREAD_LIST);
 405 }
 406
 407
 408 /*
 409  * A function to return the number of threads running in the system
 410  */
 411 int CtdlThreadGetCount(void)
 412 {
 413         return  num_threads;
 414 }
 415
 416 int CtdlThreadGetWorkers(void)
 417 {
 418         return  num_workers;
 419 }
 420
 421 double CtdlThreadGetWorkerAvg(void)
 422 {
 423         double ret;
 424
 425         begin_critical_section(S_THREAD_LIST);
 426         ret =  CtdlThreadWorkerAvg;
 427         end_critical_section(S_THREAD_LIST);
 428         return ret;
 429 }
 430
 431 double CtdlThreadGetLoadAvg(void)
 432 {
 433         double load_avg[3] = {0.0, 0.0, 0.0};
 434
 435         int ret = 0;
 436         int smp_num_cpus;
 437
 438         /* Borrowed this straight from procps */
 439         smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 440         if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
 441
 442 #ifdef HAVE_GETLOADAVG
 443         ret = getloadavg(load_avg, 3);
 444 #endif
 445         if (ret < 0)
 446                 return 0;
 447         return load_avg[0] / smp_num_cpus;
 448 /*
 449  * This old chunk of code return a value that indicated the load on citserver
 450  * This value could easily reach 100 % even when citserver was doing very little and
 451  * hence the machine has much more spare capacity.
 452  * Because this value was used to determine if the machine was under heavy load conditions
 453  * from other processes in the system then citserver could be strangled un-necesarily
 454  * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
 455  * So we have changed this.
 456
 457         begin_critical_section(S_THREAD_LIST);
 458         ret =  CtdlThreadLoadAvg;
 459         end_critical_section(S_THREAD_LIST);
 460         return ret;
 461 */
 462 }
 463
 464
 465
 466
 467 /*
 468  * A function to rename a thread
 469  * Returns a const char *
 470  */
 471 const char *CtdlThreadName(const char *name)
 472 {
 473         const char *old_name;
 474
 475         if (!CT)
 476         {
 477                 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
 478                 return NULL;
 479         }
 480         old_name = CT->name;
 481         if (name)
 482                 CT->name = name;
 483         return (old_name);
 484 }
 485
 486
 487 /*
 488  * A function to force a thread to exit
 489  */
 490 void CtdlThreadCancel(CtdlThreadNode *thread)
 491 {
 492         CtdlThreadNode *this_thread;
 493
 494         if (!thread)
 495                 this_thread = CT;
 496         else
 497                 this_thread = thread;
 498         if (!this_thread)
 499         {
 500                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
 501                 CtdlThreadStopAll();
 502                 return;
 503         }
 504
 505         if (!this_thread->thread_func)
 506         {
 507                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
 508                 CtdlThreadStopAll();
 509                 return;
 510         }
 511
 512         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
 513         citthread_cancel(this_thread->tid);
 514 }
 515
 516
 517 /*
 518  * A function for a thread to check if it has been asked to stop
 519  */
 520 int CtdlThreadCheckStop(void)
 521 {
 522         int state;
 523
 524         if (!CT)
 525         {
 526                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
 527                 CtdlThreadStopAll();
 528                 return -1;
 529         }
 530
 531         state = CT->state;
 532
 533         if (CT->signal)
 534         {
 535                 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
 536                 if (CT->signal == SIGHUP)
 537                         CT->state = CTDL_THREAD_STOP_REQ;
 538                 CT->signal = 0;
 539         }
 540         if(state == CTDL_THREAD_STOP_REQ)
 541         {
 542                 CT->state = CTDL_THREAD_STOPPING;
 543                 return -1;
 544         }
 545         else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
 546         {
 547                 return -1;
 548         }
 549         return 0;
 550 }
 551
 552
 553 /*
 554  * A function to ask a thread to exit
 555  * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
 556  */
 557 void CtdlThreadStop(CtdlThreadNode *thread)
 558 {
 559         CtdlThreadNode *this_thread;
 560
 561         if (!thread)
 562                 this_thread = CT;
 563         else
 564                 this_thread = thread;
 565         if (!this_thread)
 566                 return;
 567         if (!(this_thread->thread_func))
 568                 return;         // Don't stop garbage collector
 569
 570         if (!citthread_equal(this_thread->tid, GC_thread->tid))
 571                 citthread_kill(this_thread->tid, SIGHUP);
 572
 573         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 574         citthread_cond_signal(&this_thread->ThreadCond);
 575         citthread_cond_signal(&this_thread->SleepCond);
 576         this_thread->stop_ticker = time(NULL);
 577 }
 578
 579 /*
 580  * So we now have a sleep command that works with threads but it is in seconds
 581  */
 582 void CtdlThreadSleep(int secs)
 583 {
 584         struct timespec wake_time;
 585         struct timeval time_now;
 586
 587
 588         if (!CT)
 589         {
 590                 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
 591                 return;
 592         }
 593
 594         memset (&wake_time, 0, sizeof(struct timespec));
 595         gettimeofday(&time_now, NULL);
 596         wake_time.tv_sec = time_now.tv_sec + secs;
 597         wake_time.tv_nsec = time_now.tv_usec * 10;
 598
 599         ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
 600
 601         citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
 602         citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
 603         citthread_mutex_unlock(&CT->ThreadMutex);
 604
 605         ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 606 }
 607
 608
 609 /*
 610  * Routine to clean up our thread function on exit
 611  */
 612 static void ctdl_internal_thread_cleanup(void *arg)
 613 {
 614         /*
 615          * In here we were called by the current thread because it is exiting
 616          * NB. WE ARE THE CURRENT THREAD
 617          */
 618         if (CT)
 619         {
 620                 const char *name = CT->name;
 621                 const pid_t tid = CT->tid;
 622
 623                 CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", name, tid);
 624         }
 625         else
 626         {
 627                 CtdlLogPrintf(CTDL_NOTICE, "some ((unknown ? ? ?) Thread exited.\n");
 628         }
 629
 630         #ifdef HAVE_BACKTRACE
 631 ///     eCrash_UnregisterThread();
 632         #endif
 633
 634         citthread_mutex_lock(&CT->ThreadMutex);
 635         CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
 636         citthread_mutex_unlock(&CT->ThreadMutex);
 637 }
 638
 639 /*
 640  * A quick function to show the load averages
 641  */
 642 void ctdl_thread_internal_calc_loadavg(void)
 643 {
 644         CtdlThreadNode *that_thread;
 645         double load_avg, worker_avg;
 646         int workers = 0;
 647
 648         that_thread = CtdlThreadList;
 649         load_avg = 0;
 650         worker_avg = 0;
 651         while(that_thread)
 652         {
 653                 /* Update load averages */
 654                 ctdl_thread_internal_update_avgs(that_thread);
 655                 citthread_mutex_lock(&that_thread->ThreadMutex);
 656                 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;
 657                 that_thread->avg_sleeping /= 2;
 658                 that_thread->avg_running /= 2;
 659                 that_thread->avg_blocked /= 2;
 660                 load_avg += that_thread->load_avg;
 661                 if (that_thread->flags & CTDLTHREAD_WORKER)
 662                 {
 663                         worker_avg += that_thread->load_avg;
 664                         workers++;
 665                 }
 666 #ifdef WITH_THREADLOG
 667                 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
 668                         that_thread->name,
 669                         that_thread->tid,
 670                         CtdlThreadStates[that_thread->state],
 671                         that_thread->avg_sleeping,
 672                         that_thread->avg_running,
 673                         that_thread->avg_blocked,
 674                         that_thread->load_avg);
 675 #endif
 676                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 677                 that_thread = that_thread->next;
 678         }
 679         CtdlThreadLoadAvg = load_avg/num_threads;
 680         CtdlThreadWorkerAvg = worker_avg/workers;
 681 #ifdef WITH_THREADLOG
 682         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);
 683 #endif
 684 }
 685
 686
 687 /*
 688  * Garbage collection routine.
 689  * Gets called by main() in a loop to clean up the thread list periodically.
 690  */
 691 void CtdlThreadGC (void)
 692 {
 693         CtdlThreadNode *this_thread, *that_thread;
 694         int workers = 0, sys_workers;
 695         int ret=0;
 696
 697         begin_critical_section(S_THREAD_LIST);
 698
 699         /* Handle exiting of garbage collector thread */
 700         if(num_threads == 1)
 701                 CtdlThreadList->state = CTDL_THREAD_EXITED;
 702
 703 #ifdef WITH_THREADLOG
 704         CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
 705 #endif
 706         /*
 707          * Woke up to do garbage collection
 708          */
 709         this_thread = CtdlThreadList;
 710         while(this_thread)
 711         {
 712                 that_thread = this_thread;
 713                 this_thread = this_thread->next;
 714
 715                 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
 716                         && (!citthread_equal(that_thread->tid, citthread_self())))
 717                 {
 718                         CtdlLogPrintf(CTDL_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
 719                         terminate_stuck_sessions();
 720                 }
 721                 else
 722                 {
 723                         /**
 724                          * Catch the situation where a worker was asked to stop but couldn't and we are not
 725                          * shutting down.
 726                          */
 727                         that_thread->stop_ticker = 0;
 728                 }
 729
 730                 if (that_thread->stop_ticker + 5 == time(NULL))
 731                 {
 732                         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);
 733                         if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
 734                                 CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
 735 //                      that_thread->state = CTDL_THREAD_CANCELLED;
 736                         that_thread->stop_ticker++;
 737 //                      citthread_cancel(that_thread->tid);
 738 //                      continue;
 739                 }
 740
 741                 /* Do we need to clean up this thread? */
 742                 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
 743                 {
 744                         if(that_thread->flags & CTDLTHREAD_WORKER)
 745                                 workers++;      /* Sanity check on number of worker threads */
 746                         continue;
 747                 }
 748
 749                 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
 750                 {       /* Sanity check */
 751                         end_critical_section(S_THREAD_LIST);
 752                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
 753                         abort();
 754                         return;
 755                 }
 756
 757                 if (num_threads <= 0)
 758                 {       /* Sanity check */
 759                         end_critical_section(S_THREAD_LIST);
 760                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
 761                         abort();
 762                         return;
 763                 }
 764
 765                 if(that_thread->flags & CTDLTHREAD_WORKER)
 766                         num_workers--;  /* This is a wroker thread so reduce the count. */
 767                 num_threads--;
 768                 /* If we are unlinking the list head then the next becomes the list head */
 769                 if(that_thread->prev)
 770                         that_thread->prev->next = that_thread->next;
 771                 else
 772                         CtdlThreadList = that_thread->next;
 773                 if(that_thread->next)
 774                         that_thread->next->prev = that_thread->prev;
 775
 776                 citthread_cond_signal(&that_thread->ThreadCond);
 777                 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
 778                 citthread_mutex_lock(&that_thread->ThreadMutex);        // Make sure it has done what its doing
 779                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 780                 /*
 781                  * Join on the thread to do clean up and prevent memory leaks
 782                  * Also makes sure the thread has cleaned up after itself before we remove it from the list
 783                  * We can join on the garbage collector thread the join should just return EDEADLCK
 784                  */
 785                 ret = citthread_join (that_thread->tid, NULL);
 786                 if (ret == EDEADLK)
 787                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
 788                 else if (ret == EINVAL)
 789                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
 790                 else if (ret == ESRCH)
 791                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
 792                 else if (ret != 0)
 793                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
 794                 /*
 795                  * Now we own that thread entry
 796                  */
 797                 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
 798                         that_thread->name, that_thread->tid);
 799                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 800                 citthread_cond_destroy(&that_thread->ThreadCond);
 801                 citthread_mutex_destroy(&that_thread->SleepMutex);
 802                 citthread_cond_destroy(&that_thread->SleepCond);
 803                 citthread_attr_destroy(&that_thread->attr);
 804                 free(that_thread);
 805         }
 806         sys_workers = num_workers;
 807         end_critical_section(S_THREAD_LIST);
 808
 809         /* Sanity check number of worker threads */
 810         if (workers != sys_workers)
 811         {
 812                 CtdlLogPrintf(CTDL_EMERG,
 813                         "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
 814                         workers, sys_workers
 815                         );
 816                 abort();
 817         }
 818 }
 819
 820
 821
 822
 823 /*
 824  * Runtime function for a Citadel Thread.
 825  * This initialises the threads environment and then calls the user supplied thread function
 826  * Note that this is the REAL thread function and wraps the users thread function.
 827  */
 828 static void *ctdl_internal_thread_func (void *arg)
 829 {
 830         CtdlThreadNode *this_thread;
 831         void *ret = NULL;
 832
 833         /* lock and unlock the thread list.
 834          * This causes this thread to wait until all its creation stuff has finished before it
 835          * can continue its execution.
 836          */
 837         begin_critical_section(S_THREAD_LIST);
 838         this_thread = (CtdlThreadNode *) arg;
 839         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 840
 841         // Register the cleanup function to take care of when we exit.
 842         citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
 843         // Get our thread data structure
 844         CtdlThreadAllocTSD();
 845         CT = this_thread;
 846         this_thread->pid = getpid();
 847         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 848         /* Only change to running state if we weren't asked to stop during the create cycle
 849          * Other wise there is a window to allow this threads creation to continue to full grown and
 850          * therby prevent a shutdown of the server.
 851          */
 852         if (!CtdlThreadCheckStop())
 853         {
 854                 citthread_mutex_lock(&this_thread->ThreadMutex);
 855                 this_thread->state = CTDL_THREAD_RUNNING;
 856                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 857         }
 858         end_critical_section(S_THREAD_LIST);
 859
 860         // Register for tracing
 861         #ifdef HAVE_BACKTRACE
 862 ///     eCrash_RegisterThread(this_thread->name, 0);
 863         #endif
 864
 865         // Tell the world we are here
 866 #if defined(HAVE_SYSCALL_H) && defined (SYS_gettid)
 867         this_thread->reltid = syscall(SYS_gettid);
 868 #endif
 869         CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
 870                 this_thread->name, this_thread->tid);
 871
 872         /*
 873          * run the thread to do the work but only if we haven't been asked to stop
 874          */
 875         if (!CtdlThreadCheckStop())
 876                 ret = (this_thread->thread_func)(this_thread->user_args);
 877
 878         /*
 879          * Our thread is exiting either because it wanted to end or because the server is stopping
 880          * We need to clean up
 881          */
 882         citthread_cleanup_pop(1);       // Execute our cleanup routine and remove it
 883
 884         return(ret);
 885 }
 886
 887
 888
 889
 890 /*
 891  * Function to initialise an empty thread structure
 892  */
 893 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
 894 {
 895         int ret = 0;
 896
 897         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 898         memset (this_thread, 0, sizeof(CtdlThreadNode));
 899
 900         /* Create the mutex's early so we can use them */
 901         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 902         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 903         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 904         citthread_cond_init (&(this_thread->SleepCond), NULL);
 905
 906         this_thread->state = CTDL_THREAD_CREATE;
 907
 908         if ((ret = citthread_attr_init(&this_thread->attr))) {
 909                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 910                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 911                 citthread_cond_destroy(&(this_thread->ThreadCond));
 912                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 913                 citthread_cond_destroy(&(this_thread->SleepCond));
 914                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 915                 free(this_thread);
 916                 return NULL;
 917         }
 918
 919         /* Our per-thread stacks need to be bigger than the default size,
 920          * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
 921          * crashes on 64-bit Linux.
 922          */
 923         if (flags & CTDLTHREAD_BIGSTACK)
 924         {
 925 #ifdef WITH_THREADLOG
 926                 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
 927 #endif
 928                 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
 929                         citthread_mutex_unlock(&this_thread->ThreadMutex);
 930                         citthread_mutex_destroy(&(this_thread->ThreadMutex));
 931                         citthread_cond_destroy(&(this_thread->ThreadCond));
 932                         citthread_mutex_destroy(&(this_thread->SleepMutex));
 933                         citthread_cond_destroy(&(this_thread->SleepCond));
 934                         citthread_attr_destroy(&this_thread->attr);
 935                         CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
 936                                 strerror(ret));
 937                         free(this_thread);
 938                         return NULL;
 939                 }
 940         }
 941
 942         /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
 943          * load average for the system. If we don't do this then we create a mass of threads at the same time
 944          * because the creation didn't affect the load average.
 945          */
 946         this_thread->avg_blocked = 2;
 947
 948         return (this_thread);
 949 }
 950
 951
 952
 953
 954 /*
 955  * Internal function to create a thread.
 956  */
 957 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 958 {
 959         int ret = 0;
 960         CtdlThreadNode *this_thread;
 961
 962         if (num_threads >= 32767)
 963         {
 964                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 965                 return NULL;
 966         }
 967
 968         this_thread = malloc(sizeof(CtdlThreadNode));
 969         if (this_thread == NULL) {
 970                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 971                 return NULL;
 972         }
 973
 974         /* Initialise the thread structure */
 975         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
 976         {
 977                 free(this_thread);
 978                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
 979                 return NULL;
 980         }
 981         /*
 982          * If we got here we are going to create the thread so we must initilise the structure
 983          * first because most implimentations of threading can't create it in a stopped state
 984          * and it might want to do things with its structure that aren't initialised otherwise.
 985          */
 986         if(name)
 987         {
 988                 this_thread->name = name;
 989         }
 990         else
 991         {
 992                 this_thread->name = "Un-named Thread";
 993         }
 994
 995         this_thread->flags = flags;
 996         this_thread->thread_func = thread_func;
 997         this_thread->user_args = args;
 998
 999         begin_critical_section(S_THREAD_LIST);
1000         /*
1001          * We pass this_thread into the thread as its args so that it can find out information
1002          * about itself and it has a bit of storage space for itself, not to mention that the REAL
1003          * thread function needs to finish off the setup of the structure
1004          */
1005         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1006         {
1007                 end_critical_section(S_THREAD_LIST);
1008                 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
1009                         strerror(ret));
1010                 citthread_mutex_unlock(&this_thread->ThreadMutex);
1011                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1012                 citthread_cond_destroy(&(this_thread->ThreadCond));
1013                 citthread_mutex_destroy(&(this_thread->SleepMutex));
1014                 citthread_cond_destroy(&(this_thread->SleepCond));
1015                 citthread_attr_destroy(&this_thread->attr);
1016                 free(this_thread);
1017                 return NULL;
1018         }
1019         num_threads++;  // Increase the count of threads in the system.
1020         if(this_thread->flags & CTDLTHREAD_WORKER)
1021                 num_workers++;
1022
1023         this_thread->next = CtdlThreadList;
1024         CtdlThreadList = this_thread;
1025         if (this_thread->next)
1026                 this_thread->next->prev = this_thread;
1027         ctdl_thread_internal_calc_loadavg();
1028
1029         end_critical_section(S_THREAD_LIST);
1030
1031         return this_thread;
1032 }
1033
1034 /*
1035  * Wrapper function to create a thread
1036  * ensures the critical section and other protections are in place.
1037  * char *name = name to give to thread, if NULL, use generic name
1038  * int flags = flags to determine type of thread and standard facilities
1039  */
1040 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
1041 {
1042         CtdlThreadNode *ret = NULL;
1043
1044         ret = ctdl_internal_create_thread(name, flags, thread_func, args);
1045         return ret;
1046 }
1047
1048
1049
1050 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1051 {
1052         int ret = 0;
1053
1054         begin_critical_section(S_THREAD_LIST);
1055         /*
1056          * We pass this_thread into the thread as its args so that it can find out information
1057          * about itself and it has a bit of storage space for itself, not to mention that the REAL
1058          * thread function needs to finish off the setup of the structure
1059          */
1060         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1061         {
1062                 end_critical_section(S_THREAD_LIST);
1063                 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1064                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1065                 citthread_cond_destroy(&(this_thread->ThreadCond));
1066                 citthread_mutex_destroy(&(this_thread->SleepMutex));
1067                 citthread_cond_destroy(&(this_thread->SleepCond));
1068                 citthread_attr_destroy(&this_thread->attr);
1069                 free(this_thread);
1070                 return NULL;
1071         }
1072
1073
1074         num_threads++;  // Increase the count of threads in the system.
1075         if(this_thread->flags & CTDLTHREAD_WORKER)
1076                 num_workers++;
1077
1078         this_thread->next = CtdlThreadList;
1079         CtdlThreadList = this_thread;
1080         if (this_thread->next)
1081                 this_thread->next->prev = this_thread;
1082
1083         ctdl_thread_internal_calc_loadavg();
1084         end_critical_section(S_THREAD_LIST);
1085
1086
1087         return this_thread;
1088 }
1089
1090
1091
1092 void ctdl_thread_internal_check_scheduled(void)
1093 {
1094         CtdlThreadNode *this_thread, *that_thread;
1095         time_t now;
1096
1097         /* Don't start scheduled threads if the system wants single user mode */
1098         if (CtdlWantSingleUser())
1099                 return;
1100
1101         if (try_critical_section(S_SCHEDULE_LIST))
1102                 return; /* If this list is locked we wait till the next chance */
1103
1104         now = time(NULL);
1105
1106 #ifdef WITH_THREADLOG
1107         CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1108 #endif
1109
1110         this_thread = CtdlThreadSchedList;
1111         while(this_thread)
1112         {
1113                 that_thread = this_thread;
1114                 this_thread = this_thread->next;
1115
1116                 if (now > that_thread->when)
1117                 {
1118                         /* Unlink from schedule list */
1119                         if (that_thread->prev)
1120                                 that_thread->prev->next = that_thread->next;
1121                         else
1122                                 CtdlThreadSchedList = that_thread->next;
1123                         if (that_thread->next)
1124                                 that_thread->next->prev = that_thread->prev;
1125
1126                         that_thread->next = that_thread->prev = NULL;
1127 #ifdef WITH_THREADLOG
1128                         CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1129 #endif
1130                         if (CT->state > CTDL_THREAD_STOP_REQ)
1131                         {       /* Only start it if the system is not stopping */
1132                                 if (ctdl_thread_internal_start_scheduled (that_thread))
1133                                 {
1134 #ifdef WITH_THREADLOG
1135                                         CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
1136                                                 that_thread->name, that_thread->tid);
1137 #endif
1138                                 }
1139                         }
1140                 }
1141 #ifdef WITH_THREADLOG
1142                 else
1143                 {
1144                         CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1145                                 that_thread->name, that_thread->when - time(NULL));
1146                 }
1147 #endif
1148         }
1149         end_critical_section(S_SCHEDULE_LIST);
1150 }
1151
1152
1153 /*
1154  * A warapper function for select so we can show a thread as blocked
1155  */
1156 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1157 {
1158         int ret = 0;
1159
1160         ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1161         if (!CtdlThreadCheckStop())
1162                 ret = select(n, readfds, writefds, exceptfds, timeout);
1163         /**
1164          * If the select returned <= 0 then it failed due to an error
1165          * or timeout so this thread could stop if asked to do so.
1166          * Anything else means it needs to continue unless the system is shutting down
1167          */
1168         if (ret > 0)
1169         {
1170                 /**
1171                  * The select says this thread needs to do something useful.
1172                  * This thread was in an idle state so it may have been asked to stop
1173                  * but if the system isn't shutting down this thread is no longer
1174                  * idle and select has given it a task to do so it must not stop
1175                  * In this condition we need to force it into the running state.
1176                  * CtdlThreadGC will clear its ticker for us.
1177                  *
1178                  * FIXME: there is still a small hole here. It is possible for the sequence of locking
1179                  * to allow the state to get changed to STOP_REQ just after this code if the other thread
1180                  * has decided to change the state before this lock, it there fore has to wait till the lock
1181                  * completes but it will continue to change the state. We need something a bit better here.
1182                  */
1183                 citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1184                 if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
1185                 {
1186                         CtdlLogPrintf(CTDL_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
1187                         CT->state = CTDL_THREAD_RUNNING;
1188                 }
1189                 citthread_mutex_unlock(&CT->ThreadMutex);
1190         }
1191
1192         ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1193
1194         return ret;
1195 }
1196
1197
1198
1199 void *new_worker_thread(void *arg);
1200 extern void close_masters (void);
1201
1202
1203 void *simulation_worker (void*arg) {
1204         struct CitContext *this;
1205
1206         this = CreateNewContext();
1207         CtdlThreadSleep(1);
1208         this->kill_me = 1;
1209         this->state = CON_IDLE;
1210         dead_session_purge(1);
1211         begin_critical_section(S_SESSION_TABLE);
1212         stats_done++;
1213         end_critical_section(S_SESSION_TABLE);
1214         return NULL;
1215 }
1216
1217
1218 void *simulation_thread (void *arg)
1219 {
1220         long stats = statcount;
1221
1222         while(stats && !CtdlThreadCheckStop()) {
1223                 CtdlThreadCreate("Connection simulation worker", CTDLTHREAD_BIGSTACK, simulation_worker, NULL);
1224                 stats--;
1225         }
1226         CtdlThreadStopAll();
1227         return NULL;
1228 }
1229
1230 void go_threading(void)
1231 {
1232         int i;
1233         CtdlThreadNode *last_worker;
1234         struct timeval start, now, result;
1235         double last_duration;
1236
1237         /*
1238          * Initialise the thread system
1239          */
1240         ctdl_thread_internal_init();
1241
1242         /* Second call to module init functions now that threading is up */
1243         if (!statcount) {
1244                 initialise_modules(1);
1245                 CtdlThreadCreate("select_on_master", CTDLTHREAD_BIGSTACK, select_on_master, NULL);
1246         }
1247         else {
1248                 CtdlLogPrintf(CTDL_EMERG, "Running connection simulation stats\n");
1249                 gettimeofday(&start, NULL);
1250                 CtdlThreadCreate("Connection simulation master", CTDLTHREAD_BIGSTACK, simulation_thread, NULL);
1251         }
1252
1253
1254         /*
1255          * This thread is now used for garbage collection of other threads in the thread list
1256          */
1257         CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1258
1259         /*
1260          * We do a lot of locking and unlocking of the thread list in here.
1261          * We do this so that we can repeatedly release time for other threads
1262          * that may be waiting on the thread list.
1263          * We are a low priority thread so we can afford to do this
1264          */
1265
1266         while (CtdlThreadGetCount())
1267         {
1268                 if (CT->signal)
1269                         exit_signal = CT->signal;
1270                 if (exit_signal)
1271                 {
1272                         CtdlThreadStopAll();
1273                 }
1274                 check_sched_shutdown();
1275                 if (CT->state > CTDL_THREAD_STOP_REQ)
1276                 {
1277                         begin_critical_section(S_THREAD_LIST);
1278                         ctdl_thread_internal_calc_loadavg();
1279                         end_critical_section(S_THREAD_LIST);
1280
1281                         ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1282                 }
1283
1284                 /* Reduce the size of the worker thread pool if necessary. */
1285                 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1286                 {
1287                         /* Ask a worker thread to stop as we no longer need it */
1288                         begin_critical_section(S_THREAD_LIST);
1289                         last_worker = CtdlThreadList;
1290                         while (last_worker)
1291                         {
1292                                 citthread_mutex_lock(&last_worker->ThreadMutex);
1293                                 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1294                                 {
1295                                         citthread_mutex_unlock(&last_worker->ThreadMutex);
1296                                         break;
1297                                 }
1298                                 citthread_mutex_unlock(&last_worker->ThreadMutex);
1299                                 last_worker = last_worker->next;
1300                         }
1301                         end_critical_section(S_THREAD_LIST);
1302                         if (last_worker)
1303                         {
1304 #ifdef WITH_THREADLOG
1305                                 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1306                                         last_worker->name,
1307                                         last_worker->tid
1308                                         );
1309 #endif
1310                                 CtdlThreadStop(last_worker);
1311                         }
1312                 }
1313
1314                 /*
1315                  * If all our workers are working hard, start some more to help out
1316                  * with things
1317                  */
1318                 /* FIXME: come up with a better way to dynamically alter the number of threads
1319                  * based on the system load
1320                  */
1321                 if (!statcount) {
1322                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60)) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1323                 {
1324                         /* Only start new threads if we are not going to overload the machine */
1325                         /* Temporarily set to 10 should be enough to make sure we don't stranglew the server
1326                          * at least until we make this a config option */
1327                         if (CtdlThreadGetLoadAvg() < ((double)10.00)) {
1328                                 for (i=0; i<5 ; i++) {
1329                                         CtdlThreadCreate("Worker Thread",
1330                                                 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1331                                                 worker_thread,
1332                                                 NULL
1333                                                 );
1334                                 }
1335                         }
1336                         else
1337                                 CtdlLogPrintf (CTDL_WARNING, "Server strangled due to machine load average too high.\n");
1338                 }
1339                 }
1340
1341                 CtdlThreadGC();
1342
1343                 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1344                 {
1345                         CtdlThreadGC();
1346                 }
1347
1348 #ifdef THREADS_USESIGNALS
1349                 if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
1350 #else
1351                 if (CtdlThreadGetCount())
1352 #endif
1353                         CtdlThreadSleep(1);
1354         }
1355         /*
1356          * If the above loop exits we must be shutting down since we obviously have no threads
1357          */
1358         ctdl_thread_internal_cleanup();
1359
1360         if (statcount) {
1361                 gettimeofday(&now, NULL);
1362                 timersub(&now, &start, &result);
1363                 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
1364                 CtdlLogPrintf(CTDL_EMERG, "Simulated %ld connections in %f seconds\n", stats_done, last_duration);
1365         }
1366 }
1367
1368
1369
1370