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