citadel/threads.c

   1 /*
   2  * $Id: sysdep.c 5882 2007-12-13 19:46:05Z davew $
   3  *
   4  * Citadel "system dependent" stuff.
   5  * See copyright.txt for copyright information.
   6  *
   7  * Here's where we have the Citadel thread implimentation
   8  *
   9  */
  10
  11 #include <sys/types.h>
  12 #include <errno.h>
  13 #include <sys/socket.h>
  14 #include <unistd.h>
  15 #include <fcntl.h>
  16
  17 #if TIME_WITH_SYS_TIME
  18 # include <sys/time.h>
  19 # include <time.h>
  20 #else
  21 # if HAVE_SYS_TIME_H
  22 #  include <sys/time.h>
  23 # else
  24 #  include <time.h>
  25 # endif
  26 #endif
  27
  28 #include "threads.h"
  29 #include "ctdl_module.h"
  30 #include "modules_init.h"
  31 #include "housekeeping.h"
  32 #include "config.h"
  33 #include "citserver.h"
  34 #include "sysdep_decls.h"
  35
  36 /*
  37  * define this to use the new worker_thread method of handling connections
  38  */
  39 //#define NEW_WORKER
  40
  41 /*
  42  * New thread interface.
  43  * To create a thread you must call one of the create thread functions.
  44  * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
  45  * struct CtdlThreadNode *node = NULL;
  46  * pass in &node
  47  * If the thread is created *node will point to the thread control structure for the created thread.
  48  * If the thread creation fails *node remains NULL
  49  * Do not free the memory pointed to by *node, it doesn't belong to you.
  50  * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
  51  * remove the need for the calls to eCrashRegisterThread and friends
  52  */
  53
  54 static int num_threads = 0;                     /* Current number of threads */
  55 static int num_workers = 0;                     /* Current number of worker threads */
  56
  57 CtdlThreadNode *CtdlThreadList = NULL;
  58 CtdlThreadNode *CtdlThreadSchedList = NULL;
  59
  60 static CtdlThreadNode *GC_thread = NULL;
  61 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
  62 double CtdlThreadLoadAvg = 0;
  63 double CtdlThreadWorkerAvg = 0;
  64 citthread_key_t ThreadKey;
  65
  66 citthread_mutex_t Critters[MAX_SEMAPHORES];     /* Things needing locking */
  67
  68
  69
  70 void InitialiseSemaphores(void)
  71 {
  72         int i;
  73
  74         /* Set up a bunch of semaphores to be used for critical sections */
  75         for (i=0; i<MAX_SEMAPHORES; ++i) {
  76                 citthread_mutex_init(&Critters[i], NULL);
  77         }
  78 }
  79
  80
  81
  82
  83 /*
  84  * Obtain a semaphore lock to begin a critical section.
  85  * but only if no one else has one
  86  */
  87 int try_critical_section(int which_one)
  88 {
  89         /* For all types of critical sections except those listed here,
  90          * ensure nobody ever tries to do a critical section within a
  91          * transaction; this could lead to deadlock.
  92          */
  93         if (    (which_one != S_FLOORCACHE)
  94 #ifdef DEBUG_MEMORY_LEAKS
  95                 && (which_one != S_DEBUGMEMLEAKS)
  96 #endif
  97                 && (which_one != S_RPLIST)
  98         ) {
  99                 cdb_check_handles();
 100         }
 101         return (citthread_mutex_trylock(&Critters[which_one]));
 102 }
 103
 104
 105 /*
 106  * Obtain a semaphore lock to begin a critical section.
 107  */
 108 void begin_critical_section(int which_one)
 109 {
 110         /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
 111
 112         /* For all types of critical sections except those listed here,
 113          * ensure nobody ever tries to do a critical section within a
 114          * transaction; this could lead to deadlock.
 115          */
 116         if (    (which_one != S_FLOORCACHE)
 117 #ifdef DEBUG_MEMORY_LEAKS
 118                 && (which_one != S_DEBUGMEMLEAKS)
 119 #endif
 120                 && (which_one != S_RPLIST)
 121         ) {
 122                 cdb_check_handles();
 123         }
 124         citthread_mutex_lock(&Critters[which_one]);
 125 }
 126
 127 /*
 128  * Release a semaphore lock to end a critical section.
 129  */
 130 void end_critical_section(int which_one)
 131 {
 132         citthread_mutex_unlock(&Critters[which_one]);
 133 }
 134
 135
 136 /*
 137  * A function to destroy the TSD
 138  */
 139 static void ctdl_thread_internal_dest_tsd(void *arg)
 140 {
 141         if (arg != NULL) {
 142                 check_handles(arg);
 143                 free(arg);
 144         }
 145 }
 146
 147
 148 /*
 149  * A function to initialise the thread TSD
 150  */
 151 void ctdl_thread_internal_init_tsd(void)
 152 {
 153         int ret;
 154
 155         if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
 156                 CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
 157                 exit(CTDLEXIT_DB);
 158         }
 159 }
 160
 161 /*
 162  * Ensure that we have a key for thread-specific data.
 163  *
 164  * This should be called immediately after startup by any thread
 165  *
 166  */
 167 void CtdlThreadAllocTSD(void)
 168 {
 169         ThreadTSD *tsd;
 170
 171         if (citthread_getspecific(ThreadKey) != NULL)
 172                 return;
 173
 174         tsd = malloc(sizeof(ThreadTSD));
 175
 176         tsd->tid = NULL;
 177
 178         memset(tsd->cursors, 0, sizeof tsd->cursors);
 179         tsd->self = NULL;
 180
 181         citthread_setspecific(ThreadKey, tsd);
 182 }
 183
 184
 185 void ctdl_thread_internal_free_tsd(void)
 186 {
 187         ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
 188         citthread_setspecific(ThreadKey, NULL);
 189 }
 190
 191
 192 void ctdl_thread_internal_cleanup(void)
 193 {
 194         int i;
 195         CtdlThreadNode *this_thread, *that_thread;
 196
 197         for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
 198         {
 199                 free (CtdlThreadStates[i]);
 200         }
 201
 202         /* Clean up the scheduled thread list */
 203         this_thread = CtdlThreadSchedList;
 204         while (this_thread)
 205         {
 206                 that_thread = this_thread;
 207                 this_thread = this_thread->next;
 208                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 209                 citthread_cond_destroy(&that_thread->ThreadCond);
 210                 citthread_mutex_destroy(&that_thread->SleepMutex);
 211                 citthread_cond_destroy(&that_thread->SleepCond);
 212                 citthread_attr_destroy(&that_thread->attr);
 213                 free(that_thread);
 214         }
 215         ctdl_thread_internal_free_tsd();
 216 }
 217
 218 void ctdl_thread_internal_init(void)
 219 {
 220         CtdlThreadNode *this_thread;
 221         int ret = 0;
 222
 223         CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
 224         CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
 225         CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
 226         CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
 227         CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
 228         CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
 229         CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
 230         CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
 231         CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
 232         CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
 233
 234         /* Get ourself a thread entry */
 235         this_thread = malloc(sizeof(CtdlThreadNode));
 236         if (this_thread == NULL) {
 237                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 238                 return;
 239         }
 240         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 241         memset (this_thread, 0, sizeof(CtdlThreadNode));
 242
 243         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 244         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 245         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 246         citthread_cond_init (&(this_thread->SleepCond), NULL);
 247
 248         /* We are garbage collector so create us as running */
 249         this_thread->state = CTDL_THREAD_RUNNING;
 250
 251         if ((ret = citthread_attr_init(&this_thread->attr))) {
 252                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 253                 free(this_thread);
 254                 return;
 255         }
 256
 257         this_thread->name = "Garbage Collection Thread";
 258
 259         this_thread->tid = citthread_self();
 260         GC_thread = this_thread;
 261         CT = this_thread;
 262
 263         num_threads++;  // Increase the count of threads in the system.
 264
 265         this_thread->next = CtdlThreadList;
 266         CtdlThreadList = this_thread;
 267         if (this_thread->next)
 268                 this_thread->next->prev = this_thread;
 269         /* Set up start times */
 270         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 271         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 272 }
 273
 274
 275 /*
 276  * A function to update a threads load averages
 277  */
 278  void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
 279  {
 280         struct timeval now, result;
 281         double last_duration;
 282
 283         gettimeofday(&now, NULL);
 284         timersub(&now, &(this_thread->last_state_change), &result);
 285         /* I don't think these mutex's are needed here */
 286         citthread_mutex_lock(&this_thread->ThreadMutex);
 287         // result now has a timeval for the time we spent in the last state since we last updated
 288         last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
 289         if (this_thread->state == CTDL_THREAD_SLEEPING)
 290                 this_thread->avg_sleeping += last_duration;
 291         if (this_thread->state == CTDL_THREAD_RUNNING)
 292                 this_thread->avg_running += last_duration;
 293         if (this_thread->state == CTDL_THREAD_BLOCKED)
 294                 this_thread->avg_blocked += last_duration;
 295         memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
 296         citthread_mutex_unlock(&this_thread->ThreadMutex);
 297 }
 298
 299 /*
 300  * A function to chenge the state of a thread
 301  */
 302 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
 303 {
 304         /*
 305          * Wether we change state or not we need update the load values
 306          */
 307         ctdl_thread_internal_update_avgs(this_thread);
 308         /* This mutex not needed here? */
 309         citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
 310         if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
 311                 this_thread->state = new_state;
 312         if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
 313                 this_thread->state = new_state;
 314         if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
 315                 this_thread->state = new_state;
 316         citthread_mutex_unlock(&this_thread->ThreadMutex);
 317 }
 318
 319
 320 /*
 321  * A function to tell all threads to exit
 322  */
 323 void CtdlThreadStopAll(void)
 324 {
 325         //FIXME: The signalling of the condition should not be in the critical_section
 326         // We need to build a list of threads we are going to signal and then signal them afterwards
 327
 328         CtdlThreadNode *this_thread;
 329
 330         begin_critical_section(S_THREAD_LIST);
 331         this_thread = CtdlThreadList;
 332         while(this_thread)
 333         {
 334 #ifdef THREADS_USESIGNALS
 335                 citthread_killl(this_thread->tid, SIGHUP);
 336 #endif
 337                 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 338                 citthread_cond_signal(&this_thread->ThreadCond);
 339                 citthread_cond_signal(&this_thread->SleepCond);
 340                 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
 341                         this_thread->name, this_thread->tid);
 342                 this_thread = this_thread->next;
 343         }
 344         end_critical_section(S_THREAD_LIST);
 345 }
 346
 347
 348 /*
 349  * A function to wake up all sleeping threads
 350  */
 351 void CtdlThreadWakeAll(void)
 352 {
 353         CtdlThreadNode *this_thread;
 354
 355         CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
 356
 357         begin_critical_section(S_THREAD_LIST);
 358         this_thread = CtdlThreadList;
 359         while(this_thread)
 360         {
 361                 if (!this_thread->thread_func)
 362                 {
 363                         citthread_cond_signal(&this_thread->ThreadCond);
 364                         citthread_cond_signal(&this_thread->SleepCond);
 365                 }
 366                 this_thread = this_thread->next;
 367         }
 368         end_critical_section(S_THREAD_LIST);
 369 }
 370
 371
 372 /*
 373  * A function to return the number of threads running in the system
 374  */
 375 int CtdlThreadGetCount(void)
 376 {
 377         return  num_threads;
 378 }
 379
 380 int CtdlThreadGetWorkers(void)
 381 {
 382         return  num_workers;
 383 }
 384
 385 double CtdlThreadGetWorkerAvg(void)
 386 {
 387         double ret;
 388
 389         begin_critical_section(S_THREAD_LIST);
 390         ret =  CtdlThreadWorkerAvg;
 391         end_critical_section(S_THREAD_LIST);
 392         return ret;
 393 }
 394
 395 double CtdlThreadGetLoadAvg(void)
 396 {
 397         double ret;
 398
 399         begin_critical_section(S_THREAD_LIST);
 400         ret =  CtdlThreadLoadAvg;
 401         end_critical_section(S_THREAD_LIST);
 402         return ret;
 403 }
 404
 405
 406
 407
 408 /*
 409  * A function to rename a thread
 410  * Returns a const char *
 411  */
 412 const char *CtdlThreadName(const char *name)
 413 {
 414         const char *old_name;
 415
 416         if (!CT)
 417         {
 418                 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
 419                 return NULL;
 420         }
 421         old_name = CT->name;
 422         if (name)
 423                 CT->name = name;
 424         return (old_name);
 425 }
 426
 427
 428 /*
 429  * A function to force a thread to exit
 430  */
 431 void CtdlThreadCancel(CtdlThreadNode *thread)
 432 {
 433         CtdlThreadNode *this_thread;
 434
 435         if (!thread)
 436                 this_thread = CT;
 437         else
 438                 this_thread = thread;
 439         if (!this_thread)
 440         {
 441                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
 442                 CtdlThreadStopAll();
 443                 return;
 444         }
 445
 446         if (!this_thread->thread_func)
 447         {
 448                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
 449                 CtdlThreadStopAll();
 450                 return;
 451         }
 452
 453         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
 454         citthread_cancel(this_thread->tid);
 455 }
 456
 457
 458 /*
 459  * A function for a thread to check if it has been asked to stop
 460  */
 461 int CtdlThreadCheckStop(void)
 462 {
 463         int state;
 464
 465         if (!CT)
 466         {
 467                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
 468                 CtdlThreadStopAll();
 469                 return -1;
 470         }
 471
 472         state = CT->state;
 473
 474 #ifdef THREADS_USESIGNALS
 475         if (CT->signal)
 476                 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
 477 #endif
 478         if(state == CTDL_THREAD_STOP_REQ)
 479         {
 480                 CT->state = CTDL_THREAD_STOPPING;
 481                 return -1;
 482         }
 483         else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
 484         {
 485                 return -1;
 486         }
 487         return 0;
 488 }
 489
 490
 491 /*
 492  * A function to ask a thread to exit
 493  * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
 494  */
 495 void CtdlThreadStop(CtdlThreadNode *thread)
 496 {
 497         CtdlThreadNode *this_thread;
 498
 499         if (!thread)
 500                 this_thread = CT;
 501         else
 502                 this_thread = thread;
 503         if (!this_thread)
 504                 return;
 505         if (!(this_thread->thread_func))
 506                 return;         // Don't stop garbage collector
 507 #ifdef THREADS_USESIGNALS
 508         citthread_kill(this_thread->tid, SIGHUP);
 509 #endif
 510         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 511         citthread_cond_signal(&this_thread->ThreadCond);
 512         citthread_cond_signal(&this_thread->SleepCond);
 513 }
 514
 515 /*
 516  * So we now have a sleep command that works with threads but it is in seconds
 517  */
 518 void CtdlThreadSleep(int secs)
 519 {
 520         struct timespec wake_time;
 521         struct timeval time_now;
 522
 523
 524         if (!CT)
 525         {
 526                 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
 527                 return;
 528         }
 529
 530         memset (&wake_time, 0, sizeof(struct timespec));
 531         gettimeofday(&time_now, NULL);
 532         wake_time.tv_sec = time_now.tv_sec + secs;
 533         wake_time.tv_nsec = time_now.tv_usec * 10;
 534
 535         ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
 536
 537         citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
 538         citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
 539         citthread_mutex_unlock(&CT->ThreadMutex);
 540
 541         ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 542 }
 543
 544
 545 /*
 546  * Routine to clean up our thread function on exit
 547  */
 548 static void ctdl_internal_thread_cleanup(void *arg)
 549 {
 550         /*
 551          * In here we were called by the current thread because it is exiting
 552          * NB. WE ARE THE CURRENT THREAD
 553          */
 554         CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", CT->name, CT->tid);
 555
 556         #ifdef HAVE_BACKTRACE
 557         eCrash_UnregisterThread();
 558         #endif
 559
 560         citthread_mutex_lock(&CT->ThreadMutex);
 561         CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
 562         citthread_mutex_unlock(&CT->ThreadMutex);
 563 }
 564
 565 /*
 566  * A quick function to show the load averages
 567  */
 568 void ctdl_thread_internal_calc_loadavg(void)
 569 {
 570         CtdlThreadNode *that_thread;
 571         double load_avg, worker_avg;
 572         int workers = 0;
 573
 574         that_thread = CtdlThreadList;
 575         load_avg = 0;
 576         worker_avg = 0;
 577         while(that_thread)
 578         {
 579                 /* Update load averages */
 580                 ctdl_thread_internal_update_avgs(that_thread);
 581                 citthread_mutex_lock(&that_thread->ThreadMutex);
 582                 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;
 583                 that_thread->avg_sleeping /= 2;
 584                 that_thread->avg_running /= 2;
 585                 that_thread->avg_blocked /= 2;
 586                 load_avg += that_thread->load_avg;
 587                 if (that_thread->flags & CTDLTHREAD_WORKER)
 588                 {
 589                         worker_avg += that_thread->load_avg;
 590                         workers++;
 591                 }
 592 #ifdef WITH_THREADLOG
 593                 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
 594                         that_thread->name,
 595                         that_thread->tid,
 596                         CtdlThreadStates[that_thread->state],
 597                         that_thread->avg_sleeping,
 598                         that_thread->avg_running,
 599                         that_thread->avg_blocked,
 600                         that_thread->load_avg);
 601 #endif
 602                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 603                 that_thread = that_thread->next;
 604         }
 605         CtdlThreadLoadAvg = load_avg/num_threads;
 606         CtdlThreadWorkerAvg = worker_avg/workers;
 607 #ifdef WITH_THREADLOG
 608         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);
 609 #endif
 610 }
 611
 612
 613 /*
 614  * Garbage collection routine.
 615  * Gets called by main() in a loop to clean up the thread list periodically.
 616  */
 617 void CtdlThreadGC (void)
 618 {
 619         CtdlThreadNode *this_thread, *that_thread;
 620         int workers = 0, sys_workers;
 621         int ret=0;
 622
 623         begin_critical_section(S_THREAD_LIST);
 624
 625         /* Handle exiting of garbage collector thread */
 626         if(num_threads == 1)
 627                 CtdlThreadList->state = CTDL_THREAD_EXITED;
 628
 629 #ifdef WITH_THREADLOG
 630         CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
 631 #endif
 632         /*
 633          * Woke up to do garbage collection
 634          */
 635         this_thread = CtdlThreadList;
 636         while(this_thread)
 637         {
 638                 that_thread = this_thread;
 639                 this_thread = this_thread->next;
 640
 641                 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
 642                         && (!citthread_equal(that_thread->tid, citthread_self())))
 643                                 that_thread->stop_ticker++;
 644                 else
 645                 {
 646                         /**
 647                          * Catch the situation where a worker was asked to stop but couldn't and we are not
 648                          * shutting down.
 649                          */
 650                         that_thread->stop_ticker = 0;
 651                 }
 652
 653                 if (that_thread->stop_ticker == 5)
 654                 {
 655                         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);
 656                         if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
 657                                 CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
 658 //                      that_thread->state = CTDL_THREAD_CANCELLED;
 659                         that_thread->stop_ticker++;
 660 //                      citthread_cancel(that_thread->tid);
 661 //                      continue;
 662                 }
 663
 664                 /* Do we need to clean up this thread? */
 665                 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
 666                 {
 667                         if(that_thread->flags & CTDLTHREAD_WORKER)
 668                                 workers++;      /* Sanity check on number of worker threads */
 669                         continue;
 670                 }
 671
 672                 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
 673                 {       /* Sanity check */
 674                         end_critical_section(S_THREAD_LIST);
 675                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
 676                         abort();
 677                         return;
 678                 }
 679
 680                 if (num_threads <= 0)
 681                 {       /* Sanity check */
 682                         end_critical_section(S_THREAD_LIST);
 683                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
 684                         abort();
 685                         return;
 686                 }
 687
 688                 if(that_thread->flags & CTDLTHREAD_WORKER)
 689                         num_workers--;  /* This is a wroker thread so reduce the count. */
 690                 num_threads--;
 691                 /* If we are unlinking the list head then the next becomes the list head */
 692                 if(that_thread->prev)
 693                         that_thread->prev->next = that_thread->next;
 694                 else
 695                         CtdlThreadList = that_thread->next;
 696                 if(that_thread->next)
 697                         that_thread->next->prev = that_thread->prev;
 698
 699                 citthread_cond_signal(&that_thread->ThreadCond);
 700                 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
 701                 citthread_mutex_lock(&that_thread->ThreadMutex);        // Make sure it has done what its doing
 702                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 703                 /*
 704                  * Join on the thread to do clean up and prevent memory leaks
 705                  * Also makes sure the thread has cleaned up after itself before we remove it from the list
 706                  * We can join on the garbage collector thread the join should just return EDEADLCK
 707                  */
 708                 ret = citthread_join (that_thread->tid, NULL);
 709                 if (ret == EDEADLK)
 710                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
 711                 else if (ret == EINVAL)
 712                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
 713                 else if (ret == ESRCH)
 714                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
 715                 else if (ret != 0)
 716                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
 717                 /*
 718                  * Now we own that thread entry
 719                  */
 720                 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
 721                         that_thread->name, that_thread->tid);
 722                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 723                 citthread_cond_destroy(&that_thread->ThreadCond);
 724                 citthread_mutex_destroy(&that_thread->SleepMutex);
 725                 citthread_cond_destroy(&that_thread->SleepCond);
 726                 citthread_attr_destroy(&that_thread->attr);
 727                 free(that_thread);
 728         }
 729         sys_workers = num_workers;
 730         end_critical_section(S_THREAD_LIST);
 731
 732         /* Sanity check number of worker threads */
 733         if (workers != sys_workers)
 734         {
 735                 CtdlLogPrintf(CTDL_EMERG,
 736                         "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
 737                         workers, sys_workers
 738                         );
 739                 abort();
 740         }
 741 }
 742
 743
 744
 745
 746 /*
 747  * Runtime function for a Citadel Thread.
 748  * This initialises the threads environment and then calls the user supplied thread function
 749  * Note that this is the REAL thread function and wraps the users thread function.
 750  */
 751 static void *ctdl_internal_thread_func (void *arg)
 752 {
 753         CtdlThreadNode *this_thread;
 754         void *ret = NULL;
 755
 756         /* lock and unlock the thread list.
 757          * This causes this thread to wait until all its creation stuff has finished before it
 758          * can continue its execution.
 759          */
 760         begin_critical_section(S_THREAD_LIST);
 761         this_thread = (CtdlThreadNode *) arg;
 762         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 763 //      citthread_mutex_lock(&this_thread->ThreadMutex);
 764
 765         // Register the cleanup function to take care of when we exit.
 766         citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
 767         // Get our thread data structure
 768         CtdlThreadAllocTSD();
 769         CT = this_thread;
 770         this_thread->pid = getpid();
 771         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 772         /* Only change to running state if we weren't asked to stop during the create cycle
 773          * Other wise there is a window to allow this threads creation to continue to full grown and
 774          * therby prevent a shutdown of the server.
 775          */
 776 //      citthread_mutex_unlock(&this_thread->ThreadMutex);
 777
 778         if (!CtdlThreadCheckStop())
 779         {
 780                 citthread_mutex_lock(&this_thread->ThreadMutex);
 781                 this_thread->state = CTDL_THREAD_RUNNING;
 782                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 783         }
 784         end_critical_section(S_THREAD_LIST);
 785
 786         // Register for tracing
 787         #ifdef HAVE_BACKTRACE
 788         eCrash_RegisterThread(this_thread->name, 0);
 789         #endif
 790
 791         // Tell the world we are here
 792         CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
 793                 this_thread->name, this_thread->tid);
 794
 795         /*
 796          * run the thread to do the work but only if we haven't been asked to stop
 797          */
 798         if (!CtdlThreadCheckStop())
 799                 ret = (this_thread->thread_func)(this_thread->user_args);
 800
 801         /*
 802          * Our thread is exiting either because it wanted to end or because the server is stopping
 803          * We need to clean up
 804          */
 805         citthread_cleanup_pop(1);       // Execute our cleanup routine and remove it
 806
 807         return(ret);
 808 }
 809
 810
 811
 812
 813 /*
 814  * Function to initialise an empty thread structure
 815  */
 816 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
 817 {
 818         int ret = 0;
 819
 820         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 821         memset (this_thread, 0, sizeof(CtdlThreadNode));
 822
 823         /* Create the mutex's early so we can use them */
 824         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 825         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 826         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 827         citthread_cond_init (&(this_thread->SleepCond), NULL);
 828
 829         this_thread->state = CTDL_THREAD_CREATE;
 830
 831         if ((ret = citthread_attr_init(&this_thread->attr))) {
 832                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 833                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 834                 citthread_cond_destroy(&(this_thread->ThreadCond));
 835                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 836                 citthread_cond_destroy(&(this_thread->SleepCond));
 837                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 838                 free(this_thread);
 839                 return NULL;
 840         }
 841
 842         /* Our per-thread stacks need to be bigger than the default size,
 843          * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
 844          * crashes on 64-bit Linux.
 845          */
 846         if (flags & CTDLTHREAD_BIGSTACK)
 847         {
 848 #ifdef WITH_THREADLOG
 849                 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
 850 #endif
 851                 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
 852                         citthread_mutex_unlock(&this_thread->ThreadMutex);
 853                         citthread_mutex_destroy(&(this_thread->ThreadMutex));
 854                         citthread_cond_destroy(&(this_thread->ThreadCond));
 855                         citthread_mutex_destroy(&(this_thread->SleepMutex));
 856                         citthread_cond_destroy(&(this_thread->SleepCond));
 857                         citthread_attr_destroy(&this_thread->attr);
 858                         CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
 859                                 strerror(ret));
 860                         free(this_thread);
 861                         return NULL;
 862                 }
 863         }
 864
 865         /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
 866          * load average for the system. If we don't do this then we create a mass of threads at the same time
 867          * because the creation didn't affect the load average.
 868          */
 869         this_thread->avg_blocked = 2;
 870
 871         return (this_thread);
 872 }
 873
 874
 875
 876
 877 /*
 878  * Internal function to create a thread.
 879  */
 880 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 881 {
 882         int ret = 0;
 883         CtdlThreadNode *this_thread;
 884
 885         if (num_threads >= 32767)
 886         {
 887                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 888                 return NULL;
 889         }
 890
 891         this_thread = malloc(sizeof(CtdlThreadNode));
 892         if (this_thread == NULL) {
 893                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 894                 return NULL;
 895         }
 896
 897         /* Initialise the thread structure */
 898         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
 899         {
 900                 free(this_thread);
 901                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
 902                 return NULL;
 903         }
 904         /*
 905          * If we got here we are going to create the thread so we must initilise the structure
 906          * first because most implimentations of threading can't create it in a stopped state
 907          * and it might want to do things with its structure that aren't initialised otherwise.
 908          */
 909         if(name)
 910         {
 911                 this_thread->name = name;
 912         }
 913         else
 914         {
 915                 this_thread->name = "Un-named Thread";
 916         }
 917
 918         this_thread->flags = flags;
 919         this_thread->thread_func = thread_func;
 920         this_thread->user_args = args;
 921
 922 //      citthread_mutex_lock(&this_thread->ThreadMutex);
 923
 924         begin_critical_section(S_THREAD_LIST);
 925         /*
 926          * We pass this_thread into the thread as its args so that it can find out information
 927          * about itself and it has a bit of storage space for itself, not to mention that the REAL
 928          * thread function needs to finish off the setup of the structure
 929          */
 930         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
 931         {
 932                 end_critical_section(S_THREAD_LIST);
 933                 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
 934                         strerror(ret));
 935                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 936                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 937                 citthread_cond_destroy(&(this_thread->ThreadCond));
 938                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 939                 citthread_cond_destroy(&(this_thread->SleepCond));
 940                 citthread_attr_destroy(&this_thread->attr);
 941                 free(this_thread);
 942                 return NULL;
 943         }
 944
 945         num_threads++;  // Increase the count of threads in the system.
 946         if(this_thread->flags & CTDLTHREAD_WORKER)
 947                 num_workers++;
 948
 949         this_thread->next = CtdlThreadList;
 950         CtdlThreadList = this_thread;
 951         if (this_thread->next)
 952                 this_thread->next->prev = this_thread;
 953         ctdl_thread_internal_calc_loadavg();
 954
 955 //      citthread_mutex_unlock(&this_thread->ThreadMutex);
 956         end_critical_section(S_THREAD_LIST);
 957
 958         return this_thread;
 959 }
 960
 961 /*
 962  * Wrapper function to create a thread
 963  * ensures the critical section and other protections are in place.
 964  * char *name = name to give to thread, if NULL, use generic name
 965  * int flags = flags to determine type of thread and standard facilities
 966  */
 967 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 968 {
 969         CtdlThreadNode *ret = NULL;
 970
 971         ret = ctdl_internal_create_thread(name, flags, thread_func, args);
 972         return ret;
 973 }
 974
 975
 976
 977 /*
 978  * Internal function to schedule a thread.
 979  * Must be called from within a S_THREAD_LIST critical section
 980  */
 981 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
 982 {
 983         CtdlThreadNode *this_thread;
 984
 985         if (num_threads >= 32767)
 986         {
 987                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 988                 return NULL;
 989         }
 990
 991         this_thread = malloc(sizeof(CtdlThreadNode));
 992         if (this_thread == NULL) {
 993                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 994                 return NULL;
 995         }
 996         /* Initialise the thread structure */
 997         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
 998         {
 999                 free(this_thread);
1000                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
1001                 return NULL;
1002         }
1003
1004         /*
1005          * If we got here we are going to create the thread so we must initilise the structure
1006          * first because most implimentations of threading can't create it in a stopped state
1007          * and it might want to do things with its structure that aren't initialised otherwise.
1008          */
1009         if(name)
1010         {
1011                 this_thread->name = name;
1012         }
1013         else
1014         {
1015                 this_thread->name = "Un-named Thread";
1016         }
1017
1018         this_thread->flags = flags;
1019         this_thread->thread_func = thread_func;
1020         this_thread->user_args = args;
1021
1022         /*
1023          * When to start this thread
1024          */
1025         this_thread->when = when;
1026
1027         begin_critical_section(S_SCHEDULE_LIST);
1028         this_thread->next = CtdlThreadSchedList;
1029         CtdlThreadSchedList = this_thread;
1030         if (this_thread->next)
1031                 this_thread->next->prev = this_thread;
1032         end_critical_section(S_SCHEDULE_LIST);
1033
1034         return this_thread;
1035 }
1036
1037
1038
1039 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1040 {
1041         int ret = 0;
1042
1043 //      citthread_mutex_lock(&that_thread->ThreadMutex);
1044         begin_critical_section(S_THREAD_LIST);
1045         /*
1046          * We pass this_thread into the thread as its args so that it can find out information
1047          * about itself and it has a bit of storage space for itself, not to mention that the REAL
1048          * thread function needs to finish off the setup of the structure
1049          */
1050         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1051         {
1052                 end_critical_section(S_THREAD_LIST);
1053                 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1054 //              citthread_mutex_unlock(&this_thread->ThreadMutex);
1055                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1056                 citthread_cond_destroy(&(this_thread->ThreadCond));
1057                 citthread_mutex_destroy(&(this_thread->SleepMutex));
1058                 citthread_cond_destroy(&(this_thread->SleepCond));
1059                 citthread_attr_destroy(&this_thread->attr);
1060                 free(this_thread);
1061                 return NULL;
1062         }
1063
1064
1065         num_threads++;  // Increase the count of threads in the system.
1066         if(this_thread->flags & CTDLTHREAD_WORKER)
1067                 num_workers++;
1068
1069         this_thread->next = CtdlThreadList;
1070         CtdlThreadList = this_thread;
1071         if (this_thread->next)
1072                 this_thread->next->prev = this_thread;
1073 //      citthread_mutex_unlock(&that_thread->ThreadMutex);
1074
1075         ctdl_thread_internal_calc_loadavg();
1076         end_critical_section(S_THREAD_LIST);
1077
1078
1079         return this_thread;
1080 }
1081
1082
1083
1084 void ctdl_thread_internal_check_scheduled(void)
1085 {
1086         CtdlThreadNode *this_thread, *that_thread;
1087         time_t now;
1088
1089         if (try_critical_section(S_SCHEDULE_LIST))
1090                 return; /* If this list is locked we wait till the next chance */
1091
1092         now = time(NULL);
1093
1094 #ifdef WITH_THREADLOG
1095         CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1096 #endif
1097
1098         this_thread = CtdlThreadSchedList;
1099         while(this_thread)
1100         {
1101                 that_thread = this_thread;
1102                 this_thread = this_thread->next;
1103
1104                 if (now > that_thread->when)
1105                 {
1106                         /* Unlink from schedule list */
1107                         if (that_thread->prev)
1108                                 that_thread->prev->next = that_thread->next;
1109                         else
1110                                 CtdlThreadSchedList = that_thread->next;
1111                         if (that_thread->next)
1112                                 that_thread->next->prev = that_thread->prev;
1113
1114                         that_thread->next = that_thread->prev = NULL;
1115 #ifdef WITH_THREADLOG
1116                         CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1117 #endif
1118                         if (CT->state > CTDL_THREAD_STOP_REQ)
1119                         {       /* Only start it if the system is not stopping */
1120                                 if (ctdl_thread_internal_start_scheduled (that_thread))
1121                                 {
1122 #ifdef WITH_THREADLOG
1123                                         CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (%ud).\n",
1124                                                 that_thread->name, that_thread->tid);
1125 #endif
1126                                 }
1127                         }
1128                 }
1129 #ifdef WITH_THREADLOG
1130                 else
1131                 {
1132                         CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1133                                 that_thread->name, that_thread->when - time(NULL));
1134                 }
1135 #endif
1136         }
1137         end_critical_section(S_SCHEDULE_LIST);
1138 }
1139
1140
1141 /*
1142  * A warapper function for select so we can show a thread as blocked
1143  */
1144 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1145 {
1146         int ret;
1147
1148         ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1149         ret = select(n, readfds, writefds, exceptfds, timeout);
1150         /**
1151          * If the select returned <= 0 then it failed due to an error
1152          * or timeout so this thread could stop if asked to do so.
1153          * Anything else means it needs to continue unless the system is shutting down
1154          */
1155         if (ret <= 0)
1156         {
1157                 /**
1158                  * select says nothing to do so we can change to running if we haven't been asked to stop.
1159                  */
1160                 ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1161         }
1162         else
1163         {
1164                 /**
1165                  * The select says this thread needs to do something useful.
1166                  * This thread was in an idle state so it may have been asked to stop
1167                  * but if the system isn't shutting down this thread is no longer
1168                  * idle and select has given it a task to do so it must not stop
1169                  * In this condition we need to force it into the running state.
1170                  * CtdlThreadGC will clear its ticker for us.
1171                  */
1172                 if (GC_thread->state > CTDL_THREAD_STOP_REQ)
1173                 {
1174                         citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1175                         CT->state = CTDL_THREAD_RUNNING;
1176                         citthread_mutex_unlock(&CT->ThreadMutex);
1177                 }
1178         }
1179
1180         return ret;
1181 }
1182
1183
1184
1185 void *new_worker_thread(void *arg);
1186 extern void close_masters (void);
1187
1188
1189
1190 void go_threading(void)
1191 {
1192         int i;
1193         CtdlThreadNode *last_worker;
1194
1195         /*
1196          * Initialise the thread system
1197          */
1198         ctdl_thread_internal_init();
1199
1200         /* Second call to module init functions now that threading is up */
1201         initialise_modules(1);
1202
1203         /*
1204          * This thread is now used for garbage collection of other threads in the thread list
1205          */
1206         CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1207
1208         /*
1209          * We do a lot of locking and unlocking of the thread list in here.
1210          * We do this so that we can repeatedly release time for other threads
1211          * that may be waiting on the thread list.
1212          * We are a low priority thread so we can afford to do this
1213          */
1214
1215         while (CtdlThreadGetCount())
1216         {
1217                 if (CT->signal)
1218                         exit_signal = CT->signal;
1219                 if (exit_signal)
1220                 {
1221                         CtdlThreadStopAll();
1222 //                      close_masters();
1223                 }
1224                 check_sched_shutdown();
1225                 if (CT->state > CTDL_THREAD_STOP_REQ)
1226                 {
1227                         begin_critical_section(S_THREAD_LIST);
1228                         ctdl_thread_internal_calc_loadavg();
1229                         end_critical_section(S_THREAD_LIST);
1230
1231                         ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1232                 }
1233
1234                 /* Reduce the size of the worker thread pool if necessary. */
1235                 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1236                 {
1237                         /* Ask a worker thread to stop as we no longer need it */
1238                         begin_critical_section(S_THREAD_LIST);
1239                         last_worker = CtdlThreadList;
1240                         while (last_worker)
1241                         {
1242                                 citthread_mutex_lock(&last_worker->ThreadMutex);
1243                                 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1244                                 {
1245                                         citthread_mutex_unlock(&last_worker->ThreadMutex);
1246                                         break;
1247                                 }
1248                                 citthread_mutex_unlock(&last_worker->ThreadMutex);
1249                                 last_worker = last_worker->next;
1250                         }
1251                         end_critical_section(S_THREAD_LIST);
1252                         if (last_worker)
1253                         {
1254 #ifdef WITH_THREADLOG
1255                                 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1256                                         last_worker->name,
1257                                         last_worker->tid
1258                                         );
1259 #endif
1260                                 CtdlThreadStop(last_worker);
1261                         }
1262                 }
1263
1264                 /*
1265                  * If all our workers are working hard, start some more to help out
1266                  * with things
1267                  */
1268                 /* FIXME: come up with a better way to dynamically alter the number of threads
1269                  * based on the system load
1270                  */
1271 #ifdef NEW_WORKER
1272                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkers() <= num_sessions) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1273 #else
1274                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60) && (CtdlThreadGetLoadAvg() < 90) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1275 #endif /* NEW_WORKER */
1276                 {
1277                         for (i=0; i<5 ; i++)
1278                         {
1279 #ifdef NEW_WORKER
1280                                 CtdlThreadCreate("Worker Thread (new)",
1281                                         CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1282                                         new_worker_thread,
1283                                         NULL
1284                                         );
1285 #else
1286                                 CtdlThreadCreate("Worker Thread",
1287                                         CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1288                                         worker_thread,
1289                                         NULL
1290                                         );
1291 #endif /* NEW_WORKER */
1292                         }
1293                 }
1294
1295                 CtdlThreadGC();
1296
1297                 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1298                 {
1299                         CtdlThreadGC();
1300                 }
1301
1302                 if (CtdlThreadGetCount())
1303                         CtdlThreadSleep(1);
1304         }
1305         /*
1306          * If the above loop exits we must be shutting down since we obviously have no threads
1307          */
1308         ctdl_thread_internal_cleanup();
1309 }
1310
1311
1312
1313
1314 /*
1315  * Starting a new implimentation of a worker thread.
1316  * This new implimentation will be faster and do more work per thread.
1317  */
1318
1319 /*
1320  * Select on master socket.
1321  * First worker thread in here acquires the lock and builds an FDSET of master sockets.
1322  * then it goes into a loop selecting on the master sockets timing out every few milliseconds.
1323  * If it times out it rebiulds its list and loops.
1324  * If the select succeeds it creates a new context and returns.
1325  * During this time the other workers are selecting on existing contexts or sleeping.
1326  */
1327 void select_on_master(void)
1328 {
1329         fd_set readfds;
1330         struct ServiceFunctionHook *serviceptr;
1331         int ssock;                      /* Descriptor for client socket */
1332         int highest;
1333         int m, i;
1334         int retval = 0;
1335         struct timeval tv;
1336         struct CitContext *con;
1337         const char *old_name;
1338
1339
1340
1341         old_name = CtdlThreadName("select_on_master");
1342
1343         /* Initialize the fdset. */
1344         FD_ZERO(&readfds);
1345         highest = 0;
1346
1347         /* First, add the various master sockets to the fdset. */
1348         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1349                 m = serviceptr->msock;
1350                 FD_SET(m, &readfds);
1351                 if (m > highest) {
1352                         highest = m;
1353                 }
1354         }
1355
1356         tv.tv_sec = 1;          /* wake up every 1 sec if no input */
1357         tv.tv_usec = 0;
1358         retval = CtdlThreadSelect(highest + 1, &readfds, NULL, NULL, &tv);
1359
1360         /* Select got an error or we are shutting down so get out */
1361         if (retval == 0 || CtdlThreadCheckStop()) {
1362                 CtdlThreadName(old_name);
1363                 return;
1364         }
1365
1366         /* Select says something happened on one of our master sockets so now we handle it */
1367         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1368                 if (FD_ISSET(serviceptr->msock, &readfds)) {
1369                         ssock = accept(serviceptr->msock, NULL, 0);
1370                         if (ssock >= 0) {
1371                                 CtdlLogPrintf(CTDL_DEBUG, "New client socket %d\n", ssock);
1372                                 /* The master socket is non-blocking but the client
1373                                  * sockets need to be blocking, otherwise certain
1374                                  * operations barf on FreeBSD.  Not a fatal error.
1375                                  */
1376                                 if (fcntl(ssock, F_SETFL, 0) < 0) {
1377                                         CtdlLogPrintf(CTDL_EMERG,
1378                                                       "citserver: Can't set socket to blocking: %s\n",
1379                                                       strerror(errno));
1380                                 }
1381
1382                                 /* New context will be created already
1383                                  * set up in the CON_EXECUTING state.
1384                                  */
1385                                 con = CreateNewContext();
1386                                 CT->Context = con;
1387
1388                                 /* Assign our new socket number to it. */
1389                                 con->client_socket = ssock;
1390                                 con->h_command_function = serviceptr->h_command_function;
1391                                 con->h_async_function = serviceptr->h_async_function;
1392                                 con->ServiceName = serviceptr->ServiceName;
1393                                 /* Determine whether it's a local socket */
1394                                 if (serviceptr->sockpath != NULL)
1395                                         con->is_local_socket = 1;
1396
1397                                 /* Set the SO_REUSEADDR socket option */
1398                                 i = 1;
1399                                 setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
1400
1401                                 become_session(con);
1402                                 begin_session(con);
1403                                 serviceptr->h_greeting_function();
1404                                 become_session(NULL);
1405                                 con->state = CON_IDLE;
1406                                 break;
1407                         }
1408                 }
1409         }
1410
1411         CtdlThreadName(old_name);
1412 }
1413
1414 /*
1415  * Select on client socket.
1416  * First worker thread in here acquires the lock and builds an FDSET of client sockets.
1417  * then it selects on the client sockets timing out after 1 second.
1418  * If it times out the thread goes off to check on housekeeping etc.
1419  * If the select succeeds the thread goes off to handle the client request.
1420  * If the list of client connections is empty the threads all sleep for one second
1421  */
1422 struct CitContext *select_on_client(void)
1423 {
1424         fd_set readfds;
1425         struct timeval tv;
1426         int retval = 0;
1427         int highest=0;
1428         const char *old_name;
1429
1430
1431         old_name = CtdlThreadName("select_on_client");
1432
1433         /* Initialise the fdset */
1434         FD_ZERO(&readfds);
1435         FD_SET(CT->Context->client_socket, &readfds);
1436         highest = CT->Context->client_socket;
1437         /* Now we can select on any connections that are waiting */
1438
1439         if (!CtdlThreadCheckStop())
1440         {
1441                 tv.tv_sec = config.c_sleeping;          /* wake up every second if no input */
1442                 tv.tv_usec = 0;
1443                 retval = select(highest + 1, &readfds, NULL, NULL, &tv);
1444         }
1445         else    /* Shutting down? */
1446         {
1447                 CtdlThreadName(old_name);
1448                 return(NULL);
1449         }
1450
1451
1452         /* Now figure out who made this select() unblock.
1453          * First, check for an error or exit condition.
1454          */
1455         if (retval < 0) {
1456                 if (errno == EBADF) {
1457                         CtdlLogPrintf(CTDL_NOTICE, "select() failed: (%s)\n",
1458                                 strerror(errno));
1459                 }
1460                 if (errno != EINTR) {
1461                         CtdlLogPrintf(CTDL_EMERG, "Exiting (%s)\n", strerror(errno));
1462                         CtdlThreadStopAll();
1463                 } else if (!CtdlThreadCheckStop()) {
1464                         CtdlLogPrintf(CTDL_DEBUG, "Un handled select failure.\n");
1465                 }
1466                 CtdlThreadName(old_name);
1467                 return NULL;
1468         }
1469         else if(retval == 0)
1470         {
1471                 CtdlThreadName(old_name);
1472                 CT->Context->kill_me = 1;
1473                 CT->Context = NULL;
1474                 return CT->Context;
1475         }
1476
1477         CT->Context->state = CON_EXECUTING;
1478         CT->Context->input_waiting = 1;
1479
1480         CtdlThreadName(old_name);
1481         return (CT->Context);
1482 }
1483
1484
1485
1486 /*
1487  * Do the worker threads work when needed
1488  */
1489 int execute_session(struct CitContext *bind_me)
1490 {
1491         int force_purge;
1492
1493         become_session(bind_me);
1494
1495         /* If the client has sent a command, execute it. */
1496         if (CC->input_waiting) {
1497                 CC->h_command_function();
1498                 CC->input_waiting = 0;
1499         }
1500
1501         /* If there are asynchronous messages waiting and the
1502          * client supports it, do those now */
1503         if ((CC->is_async) && (CC->async_waiting)
1504            && (CC->h_async_function != NULL)) {
1505                 CC->h_async_function();
1506                 CC->async_waiting = 0;
1507         }
1508
1509         force_purge = CC->kill_me;
1510         if (force_purge)
1511                 CT->Context = NULL;
1512         become_session(NULL);
1513         bind_me->state = CON_IDLE;
1514         return force_purge;
1515 }
1516
1517
1518
1519 extern void dead_session_purge(int force);
1520
1521 /*
1522  * A new worker_thread loop.
1523  */
1524
1525 void *new_worker_thread(void *arg)
1526 {
1527         struct CitContext *bind_me;
1528         int force_purge;
1529
1530         while (!CtdlThreadCheckStop()) {
1531
1532                 /* make doubly sure we're not holding any stale db handles
1533                  * which might cause a deadlock.
1534                  */
1535                 cdb_check_handles();
1536                 force_purge = 0;
1537                 bind_me = NULL;         /* Which session shall we handle? */
1538
1539                 if (CT->Context == NULL)
1540                         select_on_master();
1541                 if (CtdlThreadCheckStop())
1542                         break;
1543
1544                 if (CT->Context)
1545                         bind_me = select_on_client();
1546                 if (CtdlThreadCheckStop())
1547                         break;
1548
1549                 if (bind_me)
1550                         force_purge = execute_session(bind_me);
1551
1552                 dead_session_purge(force_purge);
1553                 if (CtdlThreadCheckStop())
1554                         break;
1555
1556                 do_housekeeping();
1557         }
1558         return NULL;
1559 }