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
  42 /*
  43  * define this to use the new worker_thread method of handling connections
  44  */
  45 //#define NEW_WORKER
  46
  47 /*
  48  * New thread interface.
  49  * To create a thread you must call one of the create thread functions.
  50  * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
  51  * struct CtdlThreadNode *node = NULL;
  52  * pass in &node
  53  * If the thread is created *node will point to the thread control structure for the created thread.
  54  * If the thread creation fails *node remains NULL
  55  * Do not free the memory pointed to by *node, it doesn't belong to you.
  56  * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
  57  * remove the need for the calls to eCrashRegisterThread and friends
  58  */
  59
  60 static int num_threads = 0;                     /* Current number of threads */
  61 static int num_workers = 0;                     /* Current number of worker threads */
  62
  63 CtdlThreadNode *CtdlThreadList = NULL;
  64 CtdlThreadNode *CtdlThreadSchedList = NULL;
  65
  66 static CtdlThreadNode *GC_thread = NULL;
  67 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
  68 double CtdlThreadLoadAvg = 0;
  69 double CtdlThreadWorkerAvg = 0;
  70 citthread_key_t ThreadKey;
  71
  72 citthread_mutex_t Critters[MAX_SEMAPHORES];     /* Things needing locking */
  73
  74
  75
  76 void InitialiseSemaphores(void)
  77 {
  78         int i;
  79
  80         /* Set up a bunch of semaphores to be used for critical sections */
  81         for (i=0; i<MAX_SEMAPHORES; ++i) {
  82                 citthread_mutex_init(&Critters[i], NULL);
  83         }
  84 }
  85
  86
  87
  88
  89 /*
  90  * Obtain a semaphore lock to begin a critical section.
  91  * but only if no one else has one
  92  */
  93 int try_critical_section(int which_one)
  94 {
  95         /* For all types of critical sections except those listed here,
  96          * ensure nobody ever tries to do a critical section within a
  97          * transaction; this could lead to deadlock.
  98          */
  99         if (    (which_one != S_FLOORCACHE)
 100 #ifdef DEBUG_MEMORY_LEAKS
 101                 && (which_one != S_DEBUGMEMLEAKS)
 102 #endif
 103                 && (which_one != S_RPLIST)
 104         ) {
 105                 cdb_check_handles();
 106         }
 107         return (citthread_mutex_trylock(&Critters[which_one]));
 108 }
 109
 110
 111 /*
 112  * Obtain a semaphore lock to begin a critical section.
 113  */
 114 void begin_critical_section(int which_one)
 115 {
 116         /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
 117
 118         /* For all types of critical sections except those listed here,
 119          * ensure nobody ever tries to do a critical section within a
 120          * transaction; this could lead to deadlock.
 121          */
 122         if (    (which_one != S_FLOORCACHE)
 123 #ifdef DEBUG_MEMORY_LEAKS
 124                 && (which_one != S_DEBUGMEMLEAKS)
 125 #endif
 126                 && (which_one != S_RPLIST)
 127         ) {
 128                 cdb_check_handles();
 129         }
 130         citthread_mutex_lock(&Critters[which_one]);
 131 }
 132
 133 /*
 134  * Release a semaphore lock to end a critical section.
 135  */
 136 void end_critical_section(int which_one)
 137 {
 138         citthread_mutex_unlock(&Critters[which_one]);
 139 }
 140
 141
 142 /*
 143  * A function to destroy the TSD
 144  */
 145 static void ctdl_thread_internal_dest_tsd(void *arg)
 146 {
 147         if (arg != NULL) {
 148                 check_handles(arg);
 149                 free(arg);
 150         }
 151 }
 152
 153
 154 /*
 155  * A function to initialise the thread TSD
 156  */
 157 void ctdl_thread_internal_init_tsd(void)
 158 {
 159         int ret;
 160
 161         if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
 162                 CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
 163                 exit(CTDLEXIT_DB);
 164         }
 165 }
 166
 167 /*
 168  * Ensure that we have a key for thread-specific data.
 169  *
 170  * This should be called immediately after startup by any thread
 171  *
 172  */
 173 void CtdlThreadAllocTSD(void)
 174 {
 175         ThreadTSD *tsd;
 176
 177         if (citthread_getspecific(ThreadKey) != NULL)
 178                 return;
 179
 180         tsd = malloc(sizeof(ThreadTSD));
 181
 182         tsd->tid = NULL;
 183
 184         memset(tsd->cursors, 0, sizeof tsd->cursors);
 185         tsd->self = NULL;
 186
 187         citthread_setspecific(ThreadKey, tsd);
 188 }
 189
 190
 191 void ctdl_thread_internal_free_tsd(void)
 192 {
 193         ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
 194         citthread_setspecific(ThreadKey, NULL);
 195 }
 196
 197
 198 void ctdl_thread_internal_cleanup(void)
 199 {
 200         int i;
 201         CtdlThreadNode *this_thread, *that_thread;
 202
 203         for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
 204         {
 205                 free (CtdlThreadStates[i]);
 206         }
 207
 208         /* Clean up the scheduled thread list */
 209         this_thread = CtdlThreadSchedList;
 210         while (this_thread)
 211         {
 212                 that_thread = this_thread;
 213                 this_thread = this_thread->next;
 214                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 215                 citthread_cond_destroy(&that_thread->ThreadCond);
 216                 citthread_mutex_destroy(&that_thread->SleepMutex);
 217                 citthread_cond_destroy(&that_thread->SleepCond);
 218                 citthread_attr_destroy(&that_thread->attr);
 219                 free(that_thread);
 220         }
 221         ctdl_thread_internal_free_tsd();
 222 }
 223
 224 void ctdl_thread_internal_init(void)
 225 {
 226         CtdlThreadNode *this_thread;
 227         int ret = 0;
 228
 229         CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
 230         CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
 231         CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
 232         CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
 233         CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
 234         CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
 235         CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
 236         CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
 237         CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
 238         CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
 239
 240         /* Get ourself a thread entry */
 241         this_thread = malloc(sizeof(CtdlThreadNode));
 242         if (this_thread == NULL) {
 243                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 244                 return;
 245         }
 246         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 247         memset (this_thread, 0, sizeof(CtdlThreadNode));
 248
 249         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 250         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 251         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 252         citthread_cond_init (&(this_thread->SleepCond), NULL);
 253
 254         /* We are garbage collector so create us as running */
 255         this_thread->state = CTDL_THREAD_RUNNING;
 256
 257         if ((ret = citthread_attr_init(&this_thread->attr))) {
 258                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 259                 free(this_thread);
 260                 return;
 261         }
 262
 263         this_thread->name = "Garbage Collection Thread";
 264
 265         this_thread->tid = citthread_self();
 266         GC_thread = this_thread;
 267         CT = this_thread;
 268
 269         num_threads++;  // Increase the count of threads in the system.
 270
 271         this_thread->next = CtdlThreadList;
 272         CtdlThreadList = this_thread;
 273         if (this_thread->next)
 274                 this_thread->next->prev = this_thread;
 275         /* Set up start times */
 276         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 277         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 278 }
 279
 280
 281 /*
 282  * A function to update a threads load averages
 283  */
 284  void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
 285  {
 286         struct timeval now, result;
 287         double last_duration;
 288
 289         gettimeofday(&now, NULL);
 290         timersub(&now, &(this_thread->last_state_change), &result);
 291         /* I don't think these mutex's are needed here */
 292         citthread_mutex_lock(&this_thread->ThreadMutex);
 293         // result now has a timeval for the time we spent in the last state since we last updated
 294         last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
 295         if (this_thread->state == CTDL_THREAD_SLEEPING)
 296                 this_thread->avg_sleeping += last_duration;
 297         if (this_thread->state == CTDL_THREAD_RUNNING)
 298                 this_thread->avg_running += last_duration;
 299         if (this_thread->state == CTDL_THREAD_BLOCKED)
 300                 this_thread->avg_blocked += last_duration;
 301         memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
 302         citthread_mutex_unlock(&this_thread->ThreadMutex);
 303 }
 304
 305 /*
 306  * A function to chenge the state of a thread
 307  */
 308 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
 309 {
 310         /*
 311          * Wether we change state or not we need update the load values
 312          */
 313         ctdl_thread_internal_update_avgs(this_thread);
 314         /* This mutex not needed here? */
 315         citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
 316         if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
 317                 this_thread->state = new_state;
 318         if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
 319                 this_thread->state = new_state;
 320         if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
 321                 this_thread->state = new_state;
 322         citthread_mutex_unlock(&this_thread->ThreadMutex);
 323 }
 324
 325
 326 /*
 327  * A function to tell all threads to exit
 328  */
 329 void CtdlThreadStopAll(void)
 330 {
 331         /* First run any registered shutdown hooks.  This probably doesn't belong here. */
 332         PerformSessionHooks(EVT_SHUTDOWN);
 333
 334         //FIXME: The signalling of the condition should not be in the critical_section
 335         // We need to build a list of threads we are going to signal and then signal them afterwards
 336
 337         CtdlThreadNode *this_thread;
 338
 339         begin_critical_section(S_THREAD_LIST);
 340         this_thread = CtdlThreadList;
 341         // Ask the GC thread to stop first so everything knows we are shutting down.
 342         GC_thread->state = CTDL_THREAD_STOP_REQ;
 343         while(this_thread)
 344         {
 345 #ifdef THREADS_USESIGNALS
 346                 if (!citthread_equal(this_thread->tid, GC_thread->tid))
 347                         citthread_kill(this_thread->tid, SIGHUP);
 348 #endif
 349                 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 350                 citthread_cond_signal(&this_thread->ThreadCond);
 351                 citthread_cond_signal(&this_thread->SleepCond);
 352                 this_thread->stop_ticker = time(NULL);
 353                 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
 354                         this_thread->name, this_thread->tid);
 355                 this_thread = this_thread->next;
 356         }
 357         end_critical_section(S_THREAD_LIST);
 358 }
 359
 360
 361 /*
 362  * A function to wake up all sleeping threads
 363  */
 364 void CtdlThreadWakeAll(void)
 365 {
 366         CtdlThreadNode *this_thread;
 367
 368         CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
 369
 370         begin_critical_section(S_THREAD_LIST);
 371         this_thread = CtdlThreadList;
 372         while(this_thread)
 373         {
 374                 if (!this_thread->thread_func)
 375                 {
 376                         citthread_cond_signal(&this_thread->ThreadCond);
 377                         citthread_cond_signal(&this_thread->SleepCond);
 378                 }
 379                 this_thread = this_thread->next;
 380         }
 381         end_critical_section(S_THREAD_LIST);
 382 }
 383
 384
 385 /*
 386  * A function to return the number of threads running in the system
 387  */
 388 int CtdlThreadGetCount(void)
 389 {
 390         return  num_threads;
 391 }
 392
 393 int CtdlThreadGetWorkers(void)
 394 {
 395         return  num_workers;
 396 }
 397
 398 double CtdlThreadGetWorkerAvg(void)
 399 {
 400         double ret;
 401
 402         begin_critical_section(S_THREAD_LIST);
 403         ret =  CtdlThreadWorkerAvg;
 404         end_critical_section(S_THREAD_LIST);
 405         return ret;
 406 }
 407
 408 double CtdlThreadGetLoadAvg(void)
 409 {
 410         double ret;
 411
 412         begin_critical_section(S_THREAD_LIST);
 413         ret =  CtdlThreadLoadAvg;
 414         end_critical_section(S_THREAD_LIST);
 415         return ret;
 416 }
 417
 418
 419
 420
 421 /*
 422  * A function to rename a thread
 423  * Returns a const char *
 424  */
 425 const char *CtdlThreadName(const char *name)
 426 {
 427         const char *old_name;
 428
 429         if (!CT)
 430         {
 431                 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
 432                 return NULL;
 433         }
 434         old_name = CT->name;
 435         if (name)
 436                 CT->name = name;
 437         return (old_name);
 438 }
 439
 440
 441 /*
 442  * A function to force a thread to exit
 443  */
 444 void CtdlThreadCancel(CtdlThreadNode *thread)
 445 {
 446         CtdlThreadNode *this_thread;
 447
 448         if (!thread)
 449                 this_thread = CT;
 450         else
 451                 this_thread = thread;
 452         if (!this_thread)
 453         {
 454                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
 455                 CtdlThreadStopAll();
 456                 return;
 457         }
 458
 459         if (!this_thread->thread_func)
 460         {
 461                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
 462                 CtdlThreadStopAll();
 463                 return;
 464         }
 465
 466         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
 467         citthread_cancel(this_thread->tid);
 468 }
 469
 470
 471 /*
 472  * A function for a thread to check if it has been asked to stop
 473  */
 474 int CtdlThreadCheckStop(void)
 475 {
 476         int state;
 477
 478         if (!CT)
 479         {
 480                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
 481                 CtdlThreadStopAll();
 482                 return -1;
 483         }
 484
 485         state = CT->state;
 486
 487 #ifdef THREADS_USESIGNALS
 488         if (CT->signal)
 489         {
 490                 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
 491                 CT->signal = 0;
 492         }
 493 #endif
 494         if(state == CTDL_THREAD_STOP_REQ)
 495         {
 496                 CT->state = CTDL_THREAD_STOPPING;
 497                 return -1;
 498         }
 499         else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
 500         {
 501                 return -1;
 502         }
 503         return 0;
 504 }
 505
 506
 507 /*
 508  * A function to ask a thread to exit
 509  * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
 510  */
 511 void CtdlThreadStop(CtdlThreadNode *thread)
 512 {
 513         CtdlThreadNode *this_thread;
 514
 515         if (!thread)
 516                 this_thread = CT;
 517         else
 518                 this_thread = thread;
 519         if (!this_thread)
 520                 return;
 521         if (!(this_thread->thread_func))
 522                 return;         // Don't stop garbage collector
 523 #ifdef THREADS_USESIGNALS
 524         if (!citthread_equal(this_thread->tid, GC_thread->tid))
 525                 citthread_kill(this_thread->tid, SIGHUP);
 526 #endif
 527         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 528         citthread_cond_signal(&this_thread->ThreadCond);
 529         citthread_cond_signal(&this_thread->SleepCond);
 530         this_thread->stop_ticker = time(NULL);
 531 }
 532
 533 /*
 534  * So we now have a sleep command that works with threads but it is in seconds
 535  */
 536 void CtdlThreadSleep(int secs)
 537 {
 538         struct timespec wake_time;
 539         struct timeval time_now;
 540
 541
 542         if (!CT)
 543         {
 544                 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
 545                 return;
 546         }
 547
 548         memset (&wake_time, 0, sizeof(struct timespec));
 549         gettimeofday(&time_now, NULL);
 550         wake_time.tv_sec = time_now.tv_sec + secs;
 551         wake_time.tv_nsec = time_now.tv_usec * 10;
 552
 553         ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
 554
 555         citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
 556         citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
 557         citthread_mutex_unlock(&CT->ThreadMutex);
 558
 559         ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 560 }
 561
 562
 563 /*
 564  * Routine to clean up our thread function on exit
 565  */
 566 static void ctdl_internal_thread_cleanup(void *arg)
 567 {
 568         /*
 569          * In here we were called by the current thread because it is exiting
 570          * NB. WE ARE THE CURRENT THREAD
 571          */
 572         CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", CT->name, CT->tid);
 573
 574         #ifdef HAVE_BACKTRACE
 575         eCrash_UnregisterThread();
 576         #endif
 577
 578         citthread_mutex_lock(&CT->ThreadMutex);
 579         CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
 580         citthread_mutex_unlock(&CT->ThreadMutex);
 581 }
 582
 583 /*
 584  * A quick function to show the load averages
 585  */
 586 void ctdl_thread_internal_calc_loadavg(void)
 587 {
 588         CtdlThreadNode *that_thread;
 589         double load_avg, worker_avg;
 590         int workers = 0;
 591
 592         that_thread = CtdlThreadList;
 593         load_avg = 0;
 594         worker_avg = 0;
 595         while(that_thread)
 596         {
 597                 /* Update load averages */
 598                 ctdl_thread_internal_update_avgs(that_thread);
 599                 citthread_mutex_lock(&that_thread->ThreadMutex);
 600                 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;
 601                 that_thread->avg_sleeping /= 2;
 602                 that_thread->avg_running /= 2;
 603                 that_thread->avg_blocked /= 2;
 604                 load_avg += that_thread->load_avg;
 605                 if (that_thread->flags & CTDLTHREAD_WORKER)
 606                 {
 607                         worker_avg += that_thread->load_avg;
 608                         workers++;
 609                 }
 610 #ifdef WITH_THREADLOG
 611                 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
 612                         that_thread->name,
 613                         that_thread->tid,
 614                         CtdlThreadStates[that_thread->state],
 615                         that_thread->avg_sleeping,
 616                         that_thread->avg_running,
 617                         that_thread->avg_blocked,
 618                         that_thread->load_avg);
 619 #endif
 620                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 621                 that_thread = that_thread->next;
 622         }
 623         CtdlThreadLoadAvg = load_avg/num_threads;
 624         CtdlThreadWorkerAvg = worker_avg/workers;
 625 #ifdef WITH_THREADLOG
 626         CtdlLogPrintf(CTDL_INFO, "System load average %.2f, workers averag %.2f, threads %d, workers %d, sessions %d\n", CtdlThreadLoadAvg, CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
 627 #endif
 628 }
 629
 630
 631 /*
 632  * Garbage collection routine.
 633  * Gets called by main() in a loop to clean up the thread list periodically.
 634  */
 635 void CtdlThreadGC (void)
 636 {
 637         CtdlThreadNode *this_thread, *that_thread;
 638         int workers = 0, sys_workers;
 639         int ret=0;
 640
 641         begin_critical_section(S_THREAD_LIST);
 642
 643         /* Handle exiting of garbage collector thread */
 644         if(num_threads == 1)
 645                 CtdlThreadList->state = CTDL_THREAD_EXITED;
 646
 647 #ifdef WITH_THREADLOG
 648         CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
 649 #endif
 650         /*
 651          * Woke up to do garbage collection
 652          */
 653         this_thread = CtdlThreadList;
 654         while(this_thread)
 655         {
 656                 that_thread = this_thread;
 657                 this_thread = this_thread->next;
 658
 659                 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
 660                         && (!citthread_equal(that_thread->tid, citthread_self())))
 661                                 CtdlLogPrintf(CTDL_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
 662                 else
 663                 {
 664                         /**
 665                          * Catch the situation where a worker was asked to stop but couldn't and we are not
 666                          * shutting down.
 667                          */
 668                         that_thread->stop_ticker = 0;
 669                 }
 670
 671                 if (that_thread->stop_ticker + 5 == time(NULL))
 672                 {
 673                         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);
 674                         if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
 675                                 CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
 676 //                      that_thread->state = CTDL_THREAD_CANCELLED;
 677                         that_thread->stop_ticker++;
 678 //                      citthread_cancel(that_thread->tid);
 679 //                      continue;
 680                 }
 681
 682                 /* Do we need to clean up this thread? */
 683                 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
 684                 {
 685                         if(that_thread->flags & CTDLTHREAD_WORKER)
 686                                 workers++;      /* Sanity check on number of worker threads */
 687                         continue;
 688                 }
 689
 690                 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
 691                 {       /* Sanity check */
 692                         end_critical_section(S_THREAD_LIST);
 693                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
 694                         abort();
 695                         return;
 696                 }
 697
 698                 if (num_threads <= 0)
 699                 {       /* Sanity check */
 700                         end_critical_section(S_THREAD_LIST);
 701                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
 702                         abort();
 703                         return;
 704                 }
 705
 706                 if(that_thread->flags & CTDLTHREAD_WORKER)
 707                         num_workers--;  /* This is a wroker thread so reduce the count. */
 708                 num_threads--;
 709                 /* If we are unlinking the list head then the next becomes the list head */
 710                 if(that_thread->prev)
 711                         that_thread->prev->next = that_thread->next;
 712                 else
 713                         CtdlThreadList = that_thread->next;
 714                 if(that_thread->next)
 715                         that_thread->next->prev = that_thread->prev;
 716
 717                 citthread_cond_signal(&that_thread->ThreadCond);
 718                 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
 719                 citthread_mutex_lock(&that_thread->ThreadMutex);        // Make sure it has done what its doing
 720                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 721                 /*
 722                  * Join on the thread to do clean up and prevent memory leaks
 723                  * Also makes sure the thread has cleaned up after itself before we remove it from the list
 724                  * We can join on the garbage collector thread the join should just return EDEADLCK
 725                  */
 726                 ret = citthread_join (that_thread->tid, NULL);
 727                 if (ret == EDEADLK)
 728                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
 729                 else if (ret == EINVAL)
 730                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
 731                 else if (ret == ESRCH)
 732                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
 733                 else if (ret != 0)
 734                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
 735                 /*
 736                  * Now we own that thread entry
 737                  */
 738                 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
 739                         that_thread->name, that_thread->tid);
 740                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 741                 citthread_cond_destroy(&that_thread->ThreadCond);
 742                 citthread_mutex_destroy(&that_thread->SleepMutex);
 743                 citthread_cond_destroy(&that_thread->SleepCond);
 744                 citthread_attr_destroy(&that_thread->attr);
 745                 free(that_thread);
 746         }
 747         sys_workers = num_workers;
 748         end_critical_section(S_THREAD_LIST);
 749
 750         /* Sanity check number of worker threads */
 751         if (workers != sys_workers)
 752         {
 753                 CtdlLogPrintf(CTDL_EMERG,
 754                         "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
 755                         workers, sys_workers
 756                         );
 757                 abort();
 758         }
 759 }
 760
 761
 762
 763
 764 /*
 765  * Runtime function for a Citadel Thread.
 766  * This initialises the threads environment and then calls the user supplied thread function
 767  * Note that this is the REAL thread function and wraps the users thread function.
 768  */
 769 static void *ctdl_internal_thread_func (void *arg)
 770 {
 771         CtdlThreadNode *this_thread;
 772         void *ret = NULL;
 773
 774         /* lock and unlock the thread list.
 775          * This causes this thread to wait until all its creation stuff has finished before it
 776          * can continue its execution.
 777          */
 778         begin_critical_section(S_THREAD_LIST);
 779         this_thread = (CtdlThreadNode *) arg;
 780         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 781 //      citthread_mutex_lock(&this_thread->ThreadMutex);
 782
 783         // Register the cleanup function to take care of when we exit.
 784         citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
 785         // Get our thread data structure
 786         CtdlThreadAllocTSD();
 787         CT = this_thread;
 788         this_thread->pid = getpid();
 789         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 790         /* Only change to running state if we weren't asked to stop during the create cycle
 791          * Other wise there is a window to allow this threads creation to continue to full grown and
 792          * therby prevent a shutdown of the server.
 793          */
 794 //      citthread_mutex_unlock(&this_thread->ThreadMutex);
 795
 796         if (!CtdlThreadCheckStop())
 797         {
 798                 citthread_mutex_lock(&this_thread->ThreadMutex);
 799                 this_thread->state = CTDL_THREAD_RUNNING;
 800                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 801         }
 802         end_critical_section(S_THREAD_LIST);
 803
 804         // Register for tracing
 805         #ifdef HAVE_BACKTRACE
 806         eCrash_RegisterThread(this_thread->name, 0);
 807         #endif
 808
 809         // Tell the world we are here
 810         CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
 811                 this_thread->name, this_thread->tid);
 812
 813         /*
 814          * run the thread to do the work but only if we haven't been asked to stop
 815          */
 816         if (!CtdlThreadCheckStop())
 817                 ret = (this_thread->thread_func)(this_thread->user_args);
 818
 819         /*
 820          * Our thread is exiting either because it wanted to end or because the server is stopping
 821          * We need to clean up
 822          */
 823         citthread_cleanup_pop(1);       // Execute our cleanup routine and remove it
 824
 825         return(ret);
 826 }
 827
 828
 829
 830
 831 /*
 832  * Function to initialise an empty thread structure
 833  */
 834 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
 835 {
 836         int ret = 0;
 837
 838         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 839         memset (this_thread, 0, sizeof(CtdlThreadNode));
 840
 841         /* Create the mutex's early so we can use them */
 842         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 843         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 844         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 845         citthread_cond_init (&(this_thread->SleepCond), NULL);
 846
 847         this_thread->state = CTDL_THREAD_CREATE;
 848
 849         if ((ret = citthread_attr_init(&this_thread->attr))) {
 850                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 851                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 852                 citthread_cond_destroy(&(this_thread->ThreadCond));
 853                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 854                 citthread_cond_destroy(&(this_thread->SleepCond));
 855                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 856                 free(this_thread);
 857                 return NULL;
 858         }
 859
 860         /* Our per-thread stacks need to be bigger than the default size,
 861          * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
 862          * crashes on 64-bit Linux.
 863          */
 864         if (flags & CTDLTHREAD_BIGSTACK)
 865         {
 866 #ifdef WITH_THREADLOG
 867                 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
 868 #endif
 869                 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
 870                         citthread_mutex_unlock(&this_thread->ThreadMutex);
 871                         citthread_mutex_destroy(&(this_thread->ThreadMutex));
 872                         citthread_cond_destroy(&(this_thread->ThreadCond));
 873                         citthread_mutex_destroy(&(this_thread->SleepMutex));
 874                         citthread_cond_destroy(&(this_thread->SleepCond));
 875                         citthread_attr_destroy(&this_thread->attr);
 876                         CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
 877                                 strerror(ret));
 878                         free(this_thread);
 879                         return NULL;
 880                 }
 881         }
 882
 883         /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
 884          * load average for the system. If we don't do this then we create a mass of threads at the same time
 885          * because the creation didn't affect the load average.
 886          */
 887         this_thread->avg_blocked = 2;
 888
 889         return (this_thread);
 890 }
 891
 892
 893
 894
 895 /*
 896  * Internal function to create a thread.
 897  */
 898 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 899 {
 900         int ret = 0;
 901         CtdlThreadNode *this_thread;
 902
 903         if (num_threads >= 32767)
 904         {
 905                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 906                 return NULL;
 907         }
 908
 909         this_thread = malloc(sizeof(CtdlThreadNode));
 910         if (this_thread == NULL) {
 911                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 912                 return NULL;
 913         }
 914
 915         /* Initialise the thread structure */
 916         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
 917         {
 918                 free(this_thread);
 919                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
 920                 return NULL;
 921         }
 922         /*
 923          * If we got here we are going to create the thread so we must initilise the structure
 924          * first because most implimentations of threading can't create it in a stopped state
 925          * and it might want to do things with its structure that aren't initialised otherwise.
 926          */
 927         if(name)
 928         {
 929                 this_thread->name = name;
 930         }
 931         else
 932         {
 933                 this_thread->name = "Un-named Thread";
 934         }
 935
 936         this_thread->flags = flags;
 937         this_thread->thread_func = thread_func;
 938         this_thread->user_args = args;
 939
 940 //      citthread_mutex_lock(&this_thread->ThreadMutex);
 941
 942         begin_critical_section(S_THREAD_LIST);
 943         /*
 944          * We pass this_thread into the thread as its args so that it can find out information
 945          * about itself and it has a bit of storage space for itself, not to mention that the REAL
 946          * thread function needs to finish off the setup of the structure
 947          */
 948         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
 949         {
 950                 end_critical_section(S_THREAD_LIST);
 951                 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
 952                         strerror(ret));
 953                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 954                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 955                 citthread_cond_destroy(&(this_thread->ThreadCond));
 956                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 957                 citthread_cond_destroy(&(this_thread->SleepCond));
 958                 citthread_attr_destroy(&this_thread->attr);
 959                 free(this_thread);
 960                 return NULL;
 961         }
 962
 963         num_threads++;  // Increase the count of threads in the system.
 964         if(this_thread->flags & CTDLTHREAD_WORKER)
 965                 num_workers++;
 966
 967         this_thread->next = CtdlThreadList;
 968         CtdlThreadList = this_thread;
 969         if (this_thread->next)
 970                 this_thread->next->prev = this_thread;
 971         ctdl_thread_internal_calc_loadavg();
 972
 973 //      citthread_mutex_unlock(&this_thread->ThreadMutex);
 974         end_critical_section(S_THREAD_LIST);
 975
 976         return this_thread;
 977 }
 978
 979 /*
 980  * Wrapper function to create a thread
 981  * ensures the critical section and other protections are in place.
 982  * char *name = name to give to thread, if NULL, use generic name
 983  * int flags = flags to determine type of thread and standard facilities
 984  */
 985 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 986 {
 987         CtdlThreadNode *ret = NULL;
 988
 989         ret = ctdl_internal_create_thread(name, flags, thread_func, args);
 990         return ret;
 991 }
 992
 993
 994
 995 /*
 996  * Internal function to schedule a thread.
 997  * Must be called from within a S_THREAD_LIST critical section
 998  */
 999 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
1000 {
1001         CtdlThreadNode *this_thread;
1002
1003         if (num_threads >= 32767)
1004         {
1005                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
1006                 return NULL;
1007         }
1008
1009         this_thread = malloc(sizeof(CtdlThreadNode));
1010         if (this_thread == NULL) {
1011                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
1012                 return NULL;
1013         }
1014         /* Initialise the thread structure */
1015         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
1016         {
1017                 free(this_thread);
1018                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
1019                 return NULL;
1020         }
1021
1022         /*
1023          * If we got here we are going to create the thread so we must initilise the structure
1024          * first because most implimentations of threading can't create it in a stopped state
1025          * and it might want to do things with its structure that aren't initialised otherwise.
1026          */
1027         if(name)
1028         {
1029                 this_thread->name = name;
1030         }
1031         else
1032         {
1033                 this_thread->name = "Un-named Thread";
1034         }
1035
1036         this_thread->flags = flags;
1037         this_thread->thread_func = thread_func;
1038         this_thread->user_args = args;
1039
1040         /*
1041          * When to start this thread
1042          */
1043         this_thread->when = when;
1044
1045         begin_critical_section(S_SCHEDULE_LIST);
1046         this_thread->next = CtdlThreadSchedList;
1047         CtdlThreadSchedList = this_thread;
1048         if (this_thread->next)
1049                 this_thread->next->prev = this_thread;
1050         end_critical_section(S_SCHEDULE_LIST);
1051
1052         return this_thread;
1053 }
1054
1055
1056
1057 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1058 {
1059         int ret = 0;
1060
1061 //      citthread_mutex_lock(&that_thread->ThreadMutex);
1062         begin_critical_section(S_THREAD_LIST);
1063         /*
1064          * We pass this_thread into the thread as its args so that it can find out information
1065          * about itself and it has a bit of storage space for itself, not to mention that the REAL
1066          * thread function needs to finish off the setup of the structure
1067          */
1068         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1069         {
1070                 end_critical_section(S_THREAD_LIST);
1071                 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1072 //              citthread_mutex_unlock(&this_thread->ThreadMutex);
1073                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1074                 citthread_cond_destroy(&(this_thread->ThreadCond));
1075                 citthread_mutex_destroy(&(this_thread->SleepMutex));
1076                 citthread_cond_destroy(&(this_thread->SleepCond));
1077                 citthread_attr_destroy(&this_thread->attr);
1078                 free(this_thread);
1079                 return NULL;
1080         }
1081
1082
1083         num_threads++;  // Increase the count of threads in the system.
1084         if(this_thread->flags & CTDLTHREAD_WORKER)
1085                 num_workers++;
1086
1087         this_thread->next = CtdlThreadList;
1088         CtdlThreadList = this_thread;
1089         if (this_thread->next)
1090                 this_thread->next->prev = this_thread;
1091 //      citthread_mutex_unlock(&that_thread->ThreadMutex);
1092
1093         ctdl_thread_internal_calc_loadavg();
1094         end_critical_section(S_THREAD_LIST);
1095
1096
1097         return this_thread;
1098 }
1099
1100
1101
1102 void ctdl_thread_internal_check_scheduled(void)
1103 {
1104         CtdlThreadNode *this_thread, *that_thread;
1105         time_t now;
1106
1107         /* Don't start scheduled threads if the system wants single user mode */
1108         if (CtdlWantSingleUser())
1109                 return;
1110
1111         if (try_critical_section(S_SCHEDULE_LIST))
1112                 return; /* If this list is locked we wait till the next chance */
1113
1114         now = time(NULL);
1115
1116 #ifdef WITH_THREADLOG
1117         CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1118 #endif
1119
1120         this_thread = CtdlThreadSchedList;
1121         while(this_thread)
1122         {
1123                 that_thread = this_thread;
1124                 this_thread = this_thread->next;
1125
1126                 if (now > that_thread->when)
1127                 {
1128                         /* Unlink from schedule list */
1129                         if (that_thread->prev)
1130                                 that_thread->prev->next = that_thread->next;
1131                         else
1132                                 CtdlThreadSchedList = that_thread->next;
1133                         if (that_thread->next)
1134                                 that_thread->next->prev = that_thread->prev;
1135
1136                         that_thread->next = that_thread->prev = NULL;
1137 #ifdef WITH_THREADLOG
1138                         CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1139 #endif
1140                         if (CT->state > CTDL_THREAD_STOP_REQ)
1141                         {       /* Only start it if the system is not stopping */
1142                                 if (ctdl_thread_internal_start_scheduled (that_thread))
1143                                 {
1144 #ifdef WITH_THREADLOG
1145                                         CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
1146                                                 that_thread->name, that_thread->tid);
1147 #endif
1148                                 }
1149                         }
1150                 }
1151 #ifdef WITH_THREADLOG
1152                 else
1153                 {
1154                         CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1155                                 that_thread->name, that_thread->when - time(NULL));
1156                 }
1157 #endif
1158         }
1159         end_critical_section(S_SCHEDULE_LIST);
1160 }
1161
1162
1163 /*
1164  * A warapper function for select so we can show a thread as blocked
1165  */
1166 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1167 {
1168         int ret = 0;
1169
1170         ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1171         if (!CtdlThreadCheckStop())
1172                 ret = select(n, readfds, writefds, exceptfds, timeout);
1173         /**
1174          * If the select returned <= 0 then it failed due to an error
1175          * or timeout so this thread could stop if asked to do so.
1176          * Anything else means it needs to continue unless the system is shutting down
1177          */
1178         if (ret <= 0)
1179         {
1180                 /**
1181                  * select says nothing to do so we can change to running if we haven't been asked to stop.
1182                  */
1183                 ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1184         }
1185         else
1186         {
1187                 /**
1188                  * The select says this thread needs to do something useful.
1189                  * This thread was in an idle state so it may have been asked to stop
1190                  * but if the system isn't shutting down this thread is no longer
1191                  * idle and select has given it a task to do so it must not stop
1192                  * In this condition we need to force it into the running state.
1193                  * CtdlThreadGC will clear its ticker for us.
1194                  *
1195                  * FIXME: there is still a small hole here. It is possible for the sequence of locking
1196                  * to allow the state to get changed to STOP_REQ just after this code if the other thread
1197                  * has decided to change the state before this lock, it there fore has to wait till the lock
1198                  * completes but it will continue to change the state. We need something a bit better here.
1199                  */
1200                 citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1201                 if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
1202                 {
1203                         CtdlLogPrintf(CTDL_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
1204                         CT->state = CTDL_THREAD_RUNNING;
1205                 }
1206                 citthread_mutex_unlock(&CT->ThreadMutex);
1207         }
1208
1209         return ret;
1210 }
1211
1212
1213
1214 void *new_worker_thread(void *arg);
1215 extern void close_masters (void);
1216
1217
1218
1219 void go_threading(void)
1220 {
1221         int i;
1222         CtdlThreadNode *last_worker;
1223
1224         /*
1225          * Initialise the thread system
1226          */
1227         ctdl_thread_internal_init();
1228
1229         /* Second call to module init functions now that threading is up */
1230         initialise_modules(1);
1231
1232         /*
1233          * This thread is now used for garbage collection of other threads in the thread list
1234          */
1235         CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1236
1237         /*
1238          * We do a lot of locking and unlocking of the thread list in here.
1239          * We do this so that we can repeatedly release time for other threads
1240          * that may be waiting on the thread list.
1241          * We are a low priority thread so we can afford to do this
1242          */
1243
1244         while (CtdlThreadGetCount())
1245         {
1246                 if (CT->signal)
1247                         exit_signal = CT->signal;
1248                 if (exit_signal)
1249                 {
1250                         CtdlThreadStopAll();
1251 //                      close_masters();
1252                 }
1253                 check_sched_shutdown();
1254                 if (CT->state > CTDL_THREAD_STOP_REQ)
1255                 {
1256                         begin_critical_section(S_THREAD_LIST);
1257                         ctdl_thread_internal_calc_loadavg();
1258                         end_critical_section(S_THREAD_LIST);
1259
1260                         ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1261                 }
1262
1263                 /* Reduce the size of the worker thread pool if necessary. */
1264                 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1265                 {
1266                         /* Ask a worker thread to stop as we no longer need it */
1267                         begin_critical_section(S_THREAD_LIST);
1268                         last_worker = CtdlThreadList;
1269                         while (last_worker)
1270                         {
1271                                 citthread_mutex_lock(&last_worker->ThreadMutex);
1272                                 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1273                                 {
1274                                         citthread_mutex_unlock(&last_worker->ThreadMutex);
1275                                         break;
1276                                 }
1277                                 citthread_mutex_unlock(&last_worker->ThreadMutex);
1278                                 last_worker = last_worker->next;
1279                         }
1280                         end_critical_section(S_THREAD_LIST);
1281                         if (last_worker)
1282                         {
1283 #ifdef WITH_THREADLOG
1284                                 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1285                                         last_worker->name,
1286                                         last_worker->tid
1287                                         );
1288 #endif
1289                                 CtdlThreadStop(last_worker);
1290                         }
1291                 }
1292
1293                 /*
1294                  * If all our workers are working hard, start some more to help out
1295                  * with things
1296                  */
1297                 /* FIXME: come up with a better way to dynamically alter the number of threads
1298                  * based on the system load
1299                  */
1300 #ifdef NEW_WORKER
1301                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkers() <= num_sessions) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1302 #else
1303                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60) && (CtdlThreadGetLoadAvg() < 90) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1304 #endif /* NEW_WORKER */
1305                 {
1306                         for (i=0; i<5 ; i++)
1307                         {
1308 #ifdef NEW_WORKER
1309                                 CtdlThreadCreate("Worker Thread (new)",
1310                                         CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1311                                         new_worker_thread,
1312                                         NULL
1313                                         );
1314 #else
1315                                 CtdlThreadCreate("Worker Thread",
1316                                         CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1317                                         worker_thread,
1318                                         NULL
1319                                         );
1320 #endif /* NEW_WORKER */
1321                         }
1322                 }
1323
1324                 CtdlThreadGC();
1325
1326                 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1327                 {
1328                         CtdlThreadGC();
1329                 }
1330
1331 #ifdef THREADS_USESIGNALS
1332                 if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
1333 #else
1334                 if (CtdlThreadGetCount())
1335 #endif
1336                         CtdlThreadSleep(1);
1337         }
1338         /*
1339          * If the above loop exits we must be shutting down since we obviously have no threads
1340          */
1341         ctdl_thread_internal_cleanup();
1342 }
1343
1344
1345
1346
1347 /*
1348  * Starting a new implimentation of a worker thread.
1349  * This new implimentation will be faster and do more work per thread.
1350  */
1351
1352 /*
1353  * Select on master socket.
1354  * First worker thread in here acquires the lock and builds an FDSET of master sockets.
1355  * then it goes into a loop selecting on the master sockets timing out every few milliseconds.
1356  * If it times out it rebiulds its list and loops.
1357  * If the select succeeds it creates a new context and returns.
1358  * During this time the other workers are selecting on existing contexts or sleeping.
1359  */
1360 void select_on_master(void)
1361 {
1362         fd_set readfds;
1363         struct ServiceFunctionHook *serviceptr;
1364         int ssock;                      /* Descriptor for client socket */
1365         int highest;
1366         int m, i;
1367         int retval = 0;
1368         struct timeval tv;
1369         struct CitContext *con;
1370         const char *old_name;
1371
1372
1373
1374         old_name = CtdlThreadName("select_on_master");
1375
1376         /* Initialize the fdset. */
1377         FD_ZERO(&readfds);
1378         highest = 0;
1379
1380         /* First, add the various master sockets to the fdset. */
1381         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1382                 m = serviceptr->msock;
1383                 FD_SET(m, &readfds);
1384                 if (m > highest) {
1385                         highest = m;
1386                 }
1387         }
1388
1389         tv.tv_sec = 1;          /* wake up every 1 sec if no input */
1390         tv.tv_usec = 0;
1391         retval = CtdlThreadSelect(highest + 1, &readfds, NULL, NULL, &tv);
1392
1393         /* Select got an error or we are shutting down so get out */
1394         if (retval == 0 || CtdlThreadCheckStop()) {
1395                 CtdlThreadName(old_name);
1396                 return;
1397         }
1398
1399         /* Select says something happened on one of our master sockets so now we handle it */
1400         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1401                 if (FD_ISSET(serviceptr->msock, &readfds)) {
1402                         ssock = accept(serviceptr->msock, NULL, 0);
1403                         if (ssock >= 0) {
1404                                 CtdlLogPrintf(CTDL_DEBUG, "New client socket %d\n", ssock);
1405                                 /* The master socket is non-blocking but the client
1406                                  * sockets need to be blocking, otherwise certain
1407                                  * operations barf on FreeBSD.  Not a fatal error.
1408                                  */
1409                                 if (fcntl(ssock, F_SETFL, 0) < 0) {
1410                                         CtdlLogPrintf(CTDL_EMERG,
1411                                                       "citserver: Can't set socket to blocking: %s\n",
1412                                                       strerror(errno));
1413                                 }
1414
1415                                 /* New context will be created already
1416                                  * set up in the CON_EXECUTING state.
1417                                  */
1418                                 con = CreateNewContext();
1419                                 CT->Context = con;
1420
1421                                 /* Assign our new socket number to it. */
1422                                 con->client_socket = ssock;
1423                                 con->h_command_function = serviceptr->h_command_function;
1424                                 con->h_async_function = serviceptr->h_async_function;
1425                                 con->ServiceName = serviceptr->ServiceName;
1426                                 /* Determine whether it's a local socket */
1427                                 if (serviceptr->sockpath != NULL)
1428                                         con->is_local_socket = 1;
1429
1430                                 /* Set the SO_REUSEADDR socket option */
1431                                 i = 1;
1432                                 setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
1433
1434                                 become_session(con);
1435                                 begin_session(con);
1436                                 serviceptr->h_greeting_function();
1437                                 become_session(NULL);
1438                                 con->state = CON_IDLE;
1439                                 break;
1440                         }
1441                 }
1442         }
1443
1444         CtdlThreadName(old_name);
1445 }
1446
1447 /*
1448  * Select on client socket.
1449  * First worker thread in here acquires the lock and builds an FDSET of client sockets.
1450  * then it selects on the client sockets timing out after 1 second.
1451  * If it times out the thread goes off to check on housekeeping etc.
1452  * If the select succeeds the thread goes off to handle the client request.
1453  * If the list of client connections is empty the threads all sleep for one second
1454  */
1455 struct CitContext *select_on_client(void)
1456 {
1457         fd_set readfds;
1458         struct timeval tv;
1459         int retval = 0;
1460         int highest=0;
1461         const char *old_name;
1462
1463
1464         old_name = CtdlThreadName("select_on_client");
1465
1466         /* Initialise the fdset */
1467         FD_ZERO(&readfds);
1468         FD_SET(CT->Context->client_socket, &readfds);
1469         highest = CT->Context->client_socket;
1470         /* Now we can select on any connections that are waiting */
1471
1472         if (!CtdlThreadCheckStop())
1473         {
1474                 tv.tv_sec = config.c_sleeping;          /* wake up every second if no input */
1475                 tv.tv_usec = 0;
1476                 retval = select(highest + 1, &readfds, NULL, NULL, &tv);
1477         }
1478         else    /* Shutting down? */
1479         {
1480                 CtdlThreadName(old_name);
1481                 return(NULL);
1482         }
1483
1484
1485         /* Now figure out who made this select() unblock.
1486          * First, check for an error or exit condition.
1487          */
1488         if (retval < 0) {
1489                 if (errno == EBADF) {
1490                         CtdlLogPrintf(CTDL_NOTICE, "select() failed: (%s)\n",
1491                                 strerror(errno));
1492                 }
1493                 if (errno != EINTR) {
1494                         CtdlLogPrintf(CTDL_EMERG, "Exiting (%s)\n", strerror(errno));
1495                         CtdlThreadStopAll();
1496                 } else if (!CtdlThreadCheckStop()) {
1497                         CtdlLogPrintf(CTDL_DEBUG, "Un handled select failure.\n");
1498                 }
1499                 CtdlThreadName(old_name);
1500                 return NULL;
1501         }
1502         else if(retval == 0)
1503         {
1504                 CtdlThreadName(old_name);
1505                 CT->Context->kill_me = 1;
1506                 CT->Context = NULL;
1507                 return CT->Context;
1508         }
1509
1510         CT->Context->state = CON_EXECUTING;
1511         CT->Context->input_waiting = 1;
1512
1513         CtdlThreadName(old_name);
1514         return (CT->Context);
1515 }
1516
1517
1518
1519 /*
1520  * Do the worker threads work when needed
1521  */
1522 int execute_session(struct CitContext *bind_me)
1523 {
1524         int force_purge;
1525
1526         become_session(bind_me);
1527
1528         /* If the client has sent a command, execute it. */
1529         if (CC->input_waiting) {
1530                 CC->h_command_function();
1531                 CC->input_waiting = 0;
1532         }
1533
1534         /* If there are asynchronous messages waiting and the
1535          * client supports it, do those now */
1536         if ((CC->is_async) && (CC->async_waiting)
1537            && (CC->h_async_function != NULL)) {
1538                 CC->h_async_function();
1539                 CC->async_waiting = 0;
1540         }
1541
1542         force_purge = CC->kill_me;
1543         if (force_purge)
1544                 CT->Context = NULL;
1545         become_session(NULL);
1546         bind_me->state = CON_IDLE;
1547         return force_purge;
1548 }
1549
1550
1551
1552 extern void dead_session_purge(int force);
1553
1554 /*
1555  * A new worker_thread loop.
1556  */
1557
1558 void *new_worker_thread(void *arg)
1559 {
1560         struct CitContext *bind_me;
1561         int force_purge;
1562
1563         while (!CtdlThreadCheckStop()) {
1564
1565                 /* make doubly sure we're not holding any stale db handles
1566                  * which might cause a deadlock.
1567                  */
1568                 cdb_check_handles();
1569                 force_purge = 0;
1570                 bind_me = NULL;         /* Which session shall we handle? */
1571
1572                 if (CT->Context == NULL)
1573                         select_on_master();
1574                 if (CtdlThreadCheckStop())
1575                         break;
1576
1577                 if (CT->Context)
1578                         bind_me = select_on_client();
1579                 if (CtdlThreadCheckStop())
1580                         break;
1581
1582                 if (bind_me)
1583                         force_purge = execute_session(bind_me);
1584
1585                 dead_session_purge(force_purge);
1586                 if (CtdlThreadCheckStop())
1587                         break;
1588
1589                 do_housekeeping();
1590         }
1591         return NULL;
1592 }