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 /*
  60  * Condition variable and Mutex for thread garbage collection
  61  */
  62 /*static pthread_mutex_t thread_gc_mutex = PTHREAD_MUTEX_INITIALIZER;
  63 static pthread_cond_t thread_gc_cond = PTHREAD_COND_INITIALIZER;
  64 */
  65 static pthread_t GC_thread;
  66 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
  67 double CtdlThreadLoadAvg = 0;
  68 double CtdlThreadWorkerAvg = 0;
  69 pthread_key_t ThreadKey;
  70
  71 pthread_mutex_t Critters[MAX_SEMAPHORES];       /* Things needing locking */
  72
  73
  74 /* Mutex's and condition vars for the various select stuff */
  75 pthread_mutex_t worker_select_mutex = PTHREAD_MUTEX_INITIALIZER;
  76 pthread_mutex_t worker_select_mutex2 = PTHREAD_MUTEX_INITIALIZER;
  77
  78
  79
  80 void InitialiseSemaphores(void)
  81 {
  82         int i;
  83
  84         /* Set up a bunch of semaphores to be used for critical sections */
  85         for (i=0; i<MAX_SEMAPHORES; ++i) {
  86                 pthread_mutex_init(&Critters[i], NULL);
  87         }
  88 }
  89
  90
  91
  92
  93 /*
  94  * Obtain a semaphore lock to begin a critical section.
  95  * but only if no one else has one
  96  */
  97 int try_critical_section(int which_one)
  98 {
  99         /* For all types of critical sections except those listed here,
 100          * ensure nobody ever tries to do a critical section within a
 101          * transaction; this could lead to deadlock.
 102          */
 103         if (    (which_one != S_FLOORCACHE)
 104 #ifdef DEBUG_MEMORY_LEAKS
 105                 && (which_one != S_DEBUGMEMLEAKS)
 106 #endif
 107                 && (which_one != S_RPLIST)
 108         ) {
 109                 cdb_check_handles();
 110         }
 111         return (pthread_mutex_trylock(&Critters[which_one]));
 112 }
 113
 114
 115 /*
 116  * Obtain a semaphore lock to begin a critical section.
 117  */
 118 void begin_critical_section(int which_one)
 119 {
 120         /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
 121
 122         /* For all types of critical sections except those listed here,
 123          * ensure nobody ever tries to do a critical section within a
 124          * transaction; this could lead to deadlock.
 125          */
 126         if (    (which_one != S_FLOORCACHE)
 127 #ifdef DEBUG_MEMORY_LEAKS
 128                 && (which_one != S_DEBUGMEMLEAKS)
 129 #endif
 130                 && (which_one != S_RPLIST)
 131         ) {
 132                 cdb_check_handles();
 133         }
 134         pthread_mutex_lock(&Critters[which_one]);
 135 }
 136
 137 /*
 138  * Release a semaphore lock to end a critical section.
 139  */
 140 void end_critical_section(int which_one)
 141 {
 142         pthread_mutex_unlock(&Critters[which_one]);
 143 }
 144
 145
 146 /*
 147  * A function to destroy the TSD
 148  */
 149 static void ctdl_thread_internal_dest_tsd(void *arg)
 150 {
 151         if (arg != NULL) {
 152                 check_handles(arg);
 153                 free(arg);
 154         }
 155 }
 156
 157
 158 /*
 159  * A function to initialise the thread TSD
 160  */
 161 void ctdl_thread_internal_init_tsd(void)
 162 {
 163         int ret;
 164
 165         if ((ret = pthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
 166                 lprintf(CTDL_EMERG, "pthread_key_create: %s\n",
 167                         strerror(ret));
 168                 exit(CTDLEXIT_DB);
 169         }
 170 }
 171
 172 /*
 173  * Ensure that we have a key for thread-specific data.
 174  *
 175  * This should be called immediately after startup by any thread
 176  *
 177  */
 178 void CtdlThreadAllocTSD(void)
 179 {
 180         ThreadTSD *tsd;
 181
 182         if (pthread_getspecific(ThreadKey) != NULL)
 183                 return;
 184
 185         tsd = malloc(sizeof(ThreadTSD));
 186
 187         tsd->tid = NULL;
 188
 189         memset(tsd->cursors, 0, sizeof tsd->cursors);
 190         tsd->self = NULL;
 191
 192         pthread_setspecific(ThreadKey, tsd);
 193 }
 194
 195
 196 void ctdl_thread_internal_free_tsd(void)
 197 {
 198         ctdl_thread_internal_dest_tsd(pthread_getspecific(ThreadKey));
 199         pthread_setspecific(ThreadKey, NULL);
 200 }
 201
 202
 203 void ctdl_thread_internal_cleanup(void)
 204 {
 205         int i;
 206         CtdlThreadNode *this_thread, *that_thread;
 207
 208         for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
 209         {
 210                 free (CtdlThreadStates[i]);
 211         }
 212
 213         /* Clean up the scheduled thread list */
 214         this_thread = CtdlThreadSchedList;
 215         while (this_thread)
 216         {
 217                 that_thread = this_thread;
 218                 this_thread = this_thread->next;
 219                 pthread_mutex_destroy(&that_thread->ThreadMutex);
 220                 pthread_cond_destroy(&that_thread->ThreadCond);
 221                 pthread_mutex_destroy(&that_thread->SleepMutex);
 222                 pthread_cond_destroy(&that_thread->SleepCond);
 223                 pthread_attr_destroy(&that_thread->attr);
 224                 free(that_thread);
 225         }
 226         ctdl_thread_internal_free_tsd();
 227 }
 228
 229 void ctdl_thread_internal_init(void)
 230 {
 231         CtdlThreadNode *this_thread;
 232         int ret = 0;
 233
 234         GC_thread = pthread_self();
 235         CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
 236         CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
 237         CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
 238         CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
 239         CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
 240         CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
 241         CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
 242         CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
 243         CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
 244         CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
 245
 246         /* Get ourself a thread entry */
 247         this_thread = malloc(sizeof(CtdlThreadNode));
 248         if (this_thread == NULL) {
 249                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 250                 return;
 251         }
 252         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 253         memset (this_thread, 0, sizeof(CtdlThreadNode));
 254
 255         pthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 256         pthread_cond_init (&(this_thread->ThreadCond), NULL);
 257         pthread_mutex_init (&(this_thread->SleepMutex), NULL);
 258         pthread_cond_init (&(this_thread->SleepCond), NULL);
 259
 260         /* We are garbage collector so create us as running */
 261         this_thread->state = CTDL_THREAD_RUNNING;
 262
 263         if ((ret = pthread_attr_init(&this_thread->attr))) {
 264                 CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_init: %s\n", strerror(ret));
 265                 free(this_thread);
 266                 return;
 267         }
 268
 269         this_thread->name = "Garbage Collection Thread";
 270
 271         this_thread->tid = GC_thread;
 272         CT = this_thread;
 273
 274         num_threads++;  // Increase the count of threads in the system.
 275
 276         this_thread->next = CtdlThreadList;
 277         CtdlThreadList = this_thread;
 278         if (this_thread->next)
 279                 this_thread->next->prev = this_thread;
 280         /* Set up start times */
 281         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 282         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 283 }
 284
 285
 286 /*
 287  * A function to update a threads load averages
 288  */
 289  void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
 290  {
 291         struct timeval now, result;
 292         double last_duration;
 293
 294         gettimeofday(&now, NULL);
 295         timersub(&now, &(this_thread->last_state_change), &result);
 296         /* I don't think these mutex's are needed here */
 297         pthread_mutex_lock(&this_thread->ThreadMutex);
 298         // result now has a timeval for the time we spent in the last state since we last updated
 299         last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
 300         if (this_thread->state == CTDL_THREAD_SLEEPING)
 301                 this_thread->avg_sleeping += last_duration;
 302         if (this_thread->state == CTDL_THREAD_RUNNING)
 303                 this_thread->avg_running += last_duration;
 304         if (this_thread->state == CTDL_THREAD_BLOCKED)
 305                 this_thread->avg_blocked += last_duration;
 306         memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
 307         pthread_mutex_unlock(&this_thread->ThreadMutex);
 308 }
 309
 310 /*
 311  * A function to chenge the state of a thread
 312  */
 313 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
 314 {
 315         /*
 316          * Wether we change state or not we need update the load values
 317          */
 318         ctdl_thread_internal_update_avgs(this_thread);
 319         /* This mutex not needed here? */
 320         pthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
 321         if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
 322                 this_thread->state = new_state;
 323         if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
 324                 this_thread->state = new_state;
 325         if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
 326                 this_thread->state = new_state;
 327         pthread_mutex_unlock(&this_thread->ThreadMutex);
 328 }
 329
 330
 331 /*
 332  * A function to tell all threads to exit
 333  */
 334 void CtdlThreadStopAll(void)
 335 {
 336         //FIXME: The signalling of the condition should not be in the critical_section
 337         // We need to build a list of threads we are going to signal and then signal them afterwards
 338
 339         CtdlThreadNode *this_thread;
 340
 341         begin_critical_section(S_THREAD_LIST);
 342         this_thread = CtdlThreadList;
 343         while(this_thread)
 344         {
 345 #ifdef THREADS_USESIGNALS
 346                 pthread_kill(this_thread->tid, SIGHUP);
 347 #endif
 348                 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 349                 pthread_cond_signal(&this_thread->ThreadCond);
 350                 pthread_cond_signal(&this_thread->SleepCond);
 351                 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (%ld).\n", this_thread->name, this_thread->tid);
 352                 this_thread = this_thread->next;
 353         }
 354         end_critical_section(S_THREAD_LIST);
 355 }
 356
 357
 358 /*
 359  * A function to wake up all sleeping threads
 360  */
 361 void CtdlThreadWakeAll(void)
 362 {
 363         CtdlThreadNode *this_thread;
 364
 365         CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
 366
 367         begin_critical_section(S_THREAD_LIST);
 368         this_thread = CtdlThreadList;
 369         while(this_thread)
 370         {
 371                 if (!this_thread->thread_func)
 372                 {
 373                         pthread_cond_signal(&this_thread->ThreadCond);
 374                         pthread_cond_signal(&this_thread->SleepCond);
 375                 }
 376                 this_thread = this_thread->next;
 377         }
 378         end_critical_section(S_THREAD_LIST);
 379 }
 380
 381
 382 /*
 383  * A function to return the number of threads running in the system
 384  */
 385 int CtdlThreadGetCount(void)
 386 {
 387         return  num_threads;
 388 }
 389
 390 int CtdlThreadGetWorkers(void)
 391 {
 392         return  num_workers;
 393 }
 394
 395 double CtdlThreadGetWorkerAvg(void)
 396 {
 397         double ret;
 398
 399         begin_critical_section(S_THREAD_LIST);
 400         ret =  CtdlThreadWorkerAvg;
 401         end_critical_section(S_THREAD_LIST);
 402         return ret;
 403 }
 404
 405 double CtdlThreadGetLoadAvg(void)
 406 {
 407         double ret;
 408
 409         begin_critical_section(S_THREAD_LIST);
 410         ret =  CtdlThreadLoadAvg;
 411         end_critical_section(S_THREAD_LIST);
 412         return ret;
 413 }
 414
 415
 416
 417
 418 /*
 419  * A function to rename a thread
 420  * Returns a const char *
 421  */
 422 const char *CtdlThreadName(const char *name)
 423 {
 424         const char *old_name;
 425
 426         if (!CT)
 427         {
 428                 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
 429                 return NULL;
 430         }
 431         old_name = CT->name;
 432         if (name)
 433                 CT->name = name;
 434         return (old_name);
 435 }
 436
 437
 438 /*
 439  * A function to force a thread to exit
 440  */
 441 void CtdlThreadCancel(CtdlThreadNode *thread)
 442 {
 443         CtdlThreadNode *this_thread;
 444
 445         if (!thread)
 446                 this_thread = CT;
 447         else
 448                 this_thread = thread;
 449         if (!this_thread)
 450         {
 451                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
 452                 CtdlThreadStopAll();
 453                 return;
 454         }
 455
 456         if (!this_thread->thread_func)
 457         {
 458                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
 459                 CtdlThreadStopAll();
 460                 return;
 461         }
 462
 463         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
 464         pthread_cancel(this_thread->tid);
 465 }
 466
 467
 468
 469 /*
 470  * A function for a thread to check if it has been asked to stop
 471  */
 472 int CtdlThreadCheckStop(void)
 473 {
 474         int state;
 475
 476         if (!CT)
 477         {
 478                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
 479                 CtdlThreadStopAll();
 480                 return -1;
 481         }
 482
 483         state = CT->state;
 484
 485 #ifdef THREADS_USERSIGNALS
 486         if (CT->signal)
 487                 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
 488 #endif
 489         if(state == CTDL_THREAD_STOP_REQ)
 490         {
 491                 CT->state = CTDL_THREAD_STOPPING;
 492                 return -1;
 493         }
 494         else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
 495         {
 496                 return -1;
 497         }
 498         return 0;
 499 }
 500
 501
 502 /*
 503  * A function to ask a thread to exit
 504  * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
 505  */
 506 void CtdlThreadStop(CtdlThreadNode *thread)
 507 {
 508         CtdlThreadNode *this_thread;
 509
 510         if (!thread)
 511                 this_thread = CT;
 512         else
 513                 this_thread = thread;
 514         if (!this_thread)
 515                 return;
 516         if (!(this_thread->thread_func))
 517                 return;         // Don't stop garbage collector
 518 #ifdef THREADS_USESIGNALS
 519         pthread_kill(this_thread->tid, SIGHUP);
 520 #endif
 521         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 522         pthread_cond_signal(&this_thread->ThreadCond);
 523         pthread_cond_signal(&this_thread->SleepCond);
 524 }
 525
 526 /*
 527  * So we now have a sleep command that works with threads but it is in seconds
 528  */
 529 void CtdlThreadSleep(int secs)
 530 {
 531         struct timespec wake_time;
 532         struct timeval time_now;
 533
 534
 535         if (!CT)
 536         {
 537                 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
 538                 return;
 539         }
 540
 541         memset (&wake_time, 0, sizeof(struct timespec));
 542         gettimeofday(&time_now, NULL);
 543         wake_time.tv_sec = time_now.tv_sec + secs;
 544         wake_time.tv_nsec = time_now.tv_usec * 10;
 545
 546         ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
 547
 548         pthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
 549         pthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
 550         pthread_mutex_unlock(&CT->ThreadMutex);
 551
 552         ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 553 }
 554
 555
 556 /*
 557  * Routine to clean up our thread function on exit
 558  */
 559 static void ctdl_internal_thread_cleanup(void *arg)
 560 {
 561         /*
 562          * In here we were called by the current thread because it is exiting
 563          * NB. WE ARE THE CURRENT THREAD
 564          */
 565         CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (%ld) exited.\n", CT->name, CT->tid);
 566
 567         #ifdef HAVE_BACKTRACE
 568         eCrash_UnregisterThread();
 569         #endif
 570
 571         pthread_mutex_lock(&CT->ThreadMutex);
 572         CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
 573         pthread_mutex_unlock(&CT->ThreadMutex);
 574 }
 575
 576 /*
 577  * A quick function to show the load averages
 578  */
 579 void ctdl_thread_internal_calc_loadavg(void)
 580 {
 581         CtdlThreadNode *that_thread;
 582         double load_avg, worker_avg;
 583         int workers = 0;
 584
 585         that_thread = CtdlThreadList;
 586         load_avg = 0;
 587         worker_avg = 0;
 588         while(that_thread)
 589         {
 590                 /* Update load averages */
 591                 ctdl_thread_internal_update_avgs(that_thread);
 592                 pthread_mutex_lock(&that_thread->ThreadMutex);
 593                 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;
 594                 that_thread->avg_sleeping /= 2;
 595                 that_thread->avg_running /= 2;
 596                 that_thread->avg_blocked /= 2;
 597                 load_avg += that_thread->load_avg;
 598                 if (that_thread->flags & CTDLTHREAD_WORKER)
 599                 {
 600                         worker_avg += that_thread->load_avg;
 601                         workers++;
 602                 }
 603 #ifdef WITH_THREADLOG
 604                 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
 605                         that_thread->name,
 606                         that_thread->tid,
 607                         CtdlThreadStates[that_thread->state],
 608                         that_thread->avg_sleeping,
 609                         that_thread->avg_running,
 610                         that_thread->avg_blocked,
 611                         that_thread->load_avg);
 612 #endif
 613                 pthread_mutex_unlock(&that_thread->ThreadMutex);
 614                 that_thread = that_thread->next;
 615         }
 616         CtdlThreadLoadAvg = load_avg/num_threads;
 617         CtdlThreadWorkerAvg = worker_avg/workers;
 618 #ifdef WITH_THREADLOG
 619         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);
 620 #endif
 621 }
 622
 623
 624 /*
 625  * Garbage collection routine.
 626  * Gets called by main() in a loop to clean up the thread list periodically.
 627  */
 628 void CtdlThreadGC (void)
 629 {
 630         CtdlThreadNode *this_thread, *that_thread;
 631         int workers = 0, sys_workers;
 632         int ret=0;
 633
 634         begin_critical_section(S_THREAD_LIST);
 635
 636         /* Handle exiting of garbage collector thread */
 637         if(num_threads == 1)
 638                 CtdlThreadList->state = CTDL_THREAD_EXITED;
 639
 640 #ifdef WITH_THREADLOG
 641         CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
 642 #endif
 643         /*
 644          * Woke up to do garbage collection
 645          */
 646         this_thread = CtdlThreadList;
 647         while(this_thread)
 648         {
 649                 that_thread = this_thread;
 650                 this_thread = this_thread->next;
 651
 652                 /* Do we need to clean up this thread? */
 653                 if (that_thread->state != CTDL_THREAD_EXITED)
 654                 {
 655                         if(that_thread->flags & CTDLTHREAD_WORKER)
 656                                 workers++;      /* Sanity check on number of worker threads */
 657                         continue;
 658                 }
 659
 660                 if (pthread_equal(that_thread->tid, pthread_self()) && that_thread->thread_func)
 661                 {       /* Sanity check */
 662                         end_critical_section(S_THREAD_LIST);
 663                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
 664                         abort();
 665                         return;
 666                 }
 667
 668                 if (num_threads <= 0)
 669                 {       /* Sanity check */
 670                         end_critical_section(S_THREAD_LIST);
 671                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
 672                         abort();
 673                         return;
 674                 }
 675
 676                 if(that_thread->flags & CTDLTHREAD_WORKER)
 677                         num_workers--;  /* This is a wroker thread so reduce the count. */
 678                 num_threads--;
 679                 /* If we are unlinking the list head then the next becomes the list head */
 680                 if(that_thread->prev)
 681                         that_thread->prev->next = that_thread->next;
 682                 else
 683                         CtdlThreadList = that_thread->next;
 684                 if(that_thread->next)
 685                         that_thread->next->prev = that_thread->prev;
 686
 687                 pthread_cond_signal(&that_thread->ThreadCond);
 688                 pthread_cond_signal(&that_thread->SleepCond);   // Make sure this thread is awake
 689                 pthread_mutex_lock(&that_thread->ThreadMutex);  // Make sure it has done what its doing
 690                 pthread_mutex_unlock(&that_thread->ThreadMutex);
 691                 /*
 692                  * Join on the thread to do clean up and prevent memory leaks
 693                  * Also makes sure the thread has cleaned up after itself before we remove it from the list
 694                  * We can join on the garbage collector thread the join should just return EDEADLCK
 695                  */
 696                 ret = pthread_join (that_thread->tid, NULL);
 697                 if (ret == EDEADLK)
 698                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
 699                 else if (ret == EINVAL)
 700                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
 701                 else if (ret == ESRCH)
 702                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
 703                 else if (ret != 0)
 704                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, pthread_join returned an unknown error.\n");
 705                 /*
 706                  * Now we own that thread entry
 707                  */
 708                 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (%ld).\n", that_thread->name, that_thread->tid);
 709                 pthread_mutex_destroy(&that_thread->ThreadMutex);
 710                 pthread_cond_destroy(&that_thread->ThreadCond);
 711                 pthread_mutex_destroy(&that_thread->SleepMutex);
 712                 pthread_cond_destroy(&that_thread->SleepCond);
 713                 pthread_attr_destroy(&that_thread->attr);
 714                 free(that_thread);
 715         }
 716         sys_workers = num_workers;
 717         end_critical_section(S_THREAD_LIST);
 718
 719         /* Sanity check number of worker threads */
 720         if (workers != sys_workers)
 721         {
 722                 CtdlLogPrintf(CTDL_EMERG,
 723                         "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
 724                         workers, sys_workers
 725                         );
 726                 abort();
 727         }
 728 }
 729
 730
 731
 732
 733 /*
 734  * Runtime function for a Citadel Thread.
 735  * This initialises the threads environment and then calls the user supplied thread function
 736  * Note that this is the REAL thread function and wraps the users thread function.
 737  */
 738 static void *ctdl_internal_thread_func (void *arg)
 739 {
 740         CtdlThreadNode *this_thread;
 741         void *ret = NULL;
 742
 743         /* lock and unlock the thread list.
 744          * This causes this thread to wait until all its creation stuff has finished before it
 745          * can continue its execution.
 746          */
 747         begin_critical_section(S_THREAD_LIST);
 748         this_thread = (CtdlThreadNode *) arg;
 749         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 750         pthread_mutex_lock(&this_thread->ThreadMutex);
 751
 752         // Register the cleanup function to take care of when we exit.
 753         pthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
 754         // Get our thread data structure
 755         CtdlThreadAllocTSD();
 756         CT = this_thread;
 757         this_thread->pid = getpid();
 758         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 759         /* Only change to running state if we weren't asked to stop during the create cycle
 760          * Other wise there is a window to allow this threads creation to continue to full grown and
 761          * therby prevent a shutdown of the server.
 762          */
 763         pthread_mutex_unlock(&this_thread->ThreadMutex);
 764
 765         if (!CtdlThreadCheckStop())
 766         {
 767                 pthread_mutex_lock(&this_thread->ThreadMutex);
 768                 this_thread->state = CTDL_THREAD_RUNNING;
 769                 pthread_mutex_unlock(&this_thread->ThreadMutex);
 770         }
 771         end_critical_section(S_THREAD_LIST);
 772
 773         // Register for tracing
 774         #ifdef HAVE_BACKTRACE
 775         eCrash_RegisterThread(this_thread->name, 0);
 776         #endif
 777
 778         // Tell the world we are here
 779         CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (%ld). \n", this_thread->name, this_thread->tid);
 780
 781
 782
 783         /*
 784          * run the thread to do the work but only if we haven't been asked to stop
 785          */
 786         if (!CtdlThreadCheckStop())
 787                 ret = (this_thread->thread_func)(this_thread->user_args);
 788
 789         /*
 790          * Our thread is exiting either because it wanted to end or because the server is stopping
 791          * We need to clean up
 792          */
 793         pthread_cleanup_pop(1); // Execute our cleanup routine and remove it
 794
 795         return(ret);
 796 }
 797
 798
 799
 800 /*
 801  * Internal function to create a thread.
 802  * Must be called from within a S_THREAD_LIST critical section
 803  */
 804 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 805 {
 806         int ret = 0;
 807         CtdlThreadNode *this_thread;
 808
 809         if (num_threads >= 32767)
 810         {
 811                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 812                 return NULL;
 813         }
 814
 815         this_thread = malloc(sizeof(CtdlThreadNode));
 816         if (this_thread == NULL) {
 817                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 818                 return NULL;
 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         pthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 825         pthread_cond_init (&(this_thread->ThreadCond), NULL);
 826         pthread_mutex_init (&(this_thread->SleepMutex), NULL);
 827         pthread_cond_init (&(this_thread->SleepCond), NULL);
 828
 829         pthread_mutex_lock(&this_thread->ThreadMutex);
 830
 831         this_thread->state = CTDL_THREAD_CREATE;
 832
 833         if ((ret = pthread_attr_init(&this_thread->attr))) {
 834                 pthread_mutex_unlock(&this_thread->ThreadMutex);
 835                 pthread_mutex_destroy(&(this_thread->ThreadMutex));
 836                 pthread_cond_destroy(&(this_thread->ThreadCond));
 837                 pthread_mutex_destroy(&(this_thread->SleepMutex));
 838                 pthread_cond_destroy(&(this_thread->SleepCond));
 839                 CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_init: %s\n", strerror(ret));
 840                 free(this_thread);
 841                 return NULL;
 842         }
 843
 844         /* Our per-thread stacks need to be bigger than the default size,
 845          * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
 846          * crashes on 64-bit Linux.
 847          */
 848         if (flags & CTDLTHREAD_BIGSTACK)
 849         {
 850 #ifdef WITH_THREADLOG
 851                 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
 852 #endif
 853                 if ((ret = pthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
 854                         pthread_mutex_unlock(&this_thread->ThreadMutex);
 855                         pthread_mutex_destroy(&(this_thread->ThreadMutex));
 856                         pthread_cond_destroy(&(this_thread->ThreadCond));
 857                         pthread_mutex_destroy(&(this_thread->SleepMutex));
 858                         pthread_cond_destroy(&(this_thread->SleepCond));
 859                         pthread_attr_destroy(&this_thread->attr);
 860                         CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_setstacksize: %s\n",
 861                                 strerror(ret));
 862                         free(this_thread);
 863                         return NULL;
 864                 }
 865         }
 866
 867         /*
 868          * If we got here we are going to create the thread so we must initilise the structure
 869          * first because most implimentations of threading can't create it in a stopped state
 870          * and it might want to do things with its structure that aren't initialised otherwise.
 871          */
 872         if(name)
 873         {
 874                 this_thread->name = name;
 875         }
 876         else
 877         {
 878                 this_thread->name = "Un-named Thread";
 879         }
 880
 881         this_thread->flags = flags;
 882         this_thread->thread_func = thread_func;
 883         this_thread->user_args = args;
 884         /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
 885          * load average for the system. If we don't do this then we create a mass of threads at the same time
 886          * because the creation didn't affect the load average.
 887          */
 888         this_thread->avg_blocked = 2;
 889
 890         /*
 891          * We pass this_thread into the thread as its args so that it can find out information
 892          * about itself and it has a bit of storage space for itself, not to mention that the REAL
 893          * thread function needs to finish off the setup of the structure
 894          */
 895         if ((ret = pthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
 896         {
 897
 898                 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
 899                         strerror(ret));
 900                 pthread_mutex_unlock(&this_thread->ThreadMutex);
 901                 pthread_mutex_destroy(&(this_thread->ThreadMutex));
 902                 pthread_cond_destroy(&(this_thread->ThreadCond));
 903                 pthread_mutex_destroy(&(this_thread->SleepMutex));
 904                 pthread_cond_destroy(&(this_thread->SleepCond));
 905                 pthread_attr_destroy(&this_thread->attr);
 906                 free(this_thread);
 907                 return NULL;
 908         }
 909
 910         num_threads++;  // Increase the count of threads in the system.
 911         if(this_thread->flags & CTDLTHREAD_WORKER)
 912                 num_workers++;
 913
 914         this_thread->next = CtdlThreadList;
 915         CtdlThreadList = this_thread;
 916         if (this_thread->next)
 917                 this_thread->next->prev = this_thread;
 918
 919         pthread_mutex_unlock(&this_thread->ThreadMutex);
 920
 921         ctdl_thread_internal_calc_loadavg();
 922         return this_thread;
 923 }
 924
 925 /*
 926  * Wrapper function to create a thread
 927  * ensures the critical section and other protections are in place.
 928  * char *name = name to give to thread, if NULL, use generic name
 929  * int flags = flags to determine type of thread and standard facilities
 930  */
 931 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 932 {
 933         CtdlThreadNode *ret = NULL;
 934
 935         begin_critical_section(S_THREAD_LIST);
 936         ret = ctdl_internal_create_thread(name, flags, thread_func, args);
 937         end_critical_section(S_THREAD_LIST);
 938         return ret;
 939 }
 940
 941
 942
 943 /*
 944  * Internal function to schedule a thread.
 945  * Must be called from within a S_THREAD_LIST critical section
 946  */
 947 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
 948 {
 949         int ret = 0;
 950         CtdlThreadNode *this_thread;
 951
 952         if (num_threads >= 32767)
 953         {
 954                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 955                 return NULL;
 956         }
 957
 958         this_thread = malloc(sizeof(CtdlThreadNode));
 959         if (this_thread == NULL) {
 960                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 961                 return NULL;
 962         }
 963         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 964         memset (this_thread, 0, sizeof(CtdlThreadNode));
 965
 966         /* Create the mutex's early so we can use them */
 967         pthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 968         pthread_cond_init (&(this_thread->ThreadCond), NULL);
 969         pthread_mutex_init (&(this_thread->SleepMutex), NULL);
 970         pthread_cond_init (&(this_thread->SleepCond), NULL);
 971
 972         this_thread->state = CTDL_THREAD_CREATE;
 973
 974         if ((ret = pthread_attr_init(&this_thread->attr))) {
 975                 pthread_mutex_destroy(&(this_thread->ThreadMutex));
 976                 pthread_cond_destroy(&(this_thread->ThreadCond));
 977                 pthread_mutex_destroy(&(this_thread->SleepMutex));
 978                 pthread_cond_destroy(&(this_thread->SleepCond));
 979                 CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_init: %s\n", strerror(ret));
 980                 free(this_thread);
 981                 return NULL;
 982         }
 983
 984         /* Our per-thread stacks need to be bigger than the default size,
 985          * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
 986          * crashes on 64-bit Linux.
 987          */
 988         if (flags & CTDLTHREAD_BIGSTACK)
 989         {
 990                 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
 991                 if ((ret = pthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
 992                         pthread_mutex_destroy(&(this_thread->ThreadMutex));
 993                         pthread_cond_destroy(&(this_thread->ThreadCond));
 994                         pthread_mutex_destroy(&(this_thread->SleepMutex));
 995                         pthread_cond_destroy(&(this_thread->SleepCond));
 996                         pthread_attr_destroy(&this_thread->attr);
 997                         CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_setstacksize: %s\n",
 998                                 strerror(ret));
 999                         free(this_thread);
1000                         return NULL;
1001                 }
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         /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
1022          * load average for the system. If we don't do this then we create a mass of threads at the same time
1023          * because the creation didn't affect the load average.
1024          */
1025         this_thread->avg_blocked = 2;
1026
1027         /*
1028          * When to start this thread
1029          */
1030         this_thread->when = when;
1031
1032         begin_critical_section(S_SCHEDULE_LIST);
1033         this_thread->next = CtdlThreadSchedList;
1034         CtdlThreadSchedList = this_thread;
1035         if (this_thread->next)
1036                 this_thread->next->prev = this_thread;
1037         end_critical_section(S_SCHEDULE_LIST);
1038
1039         return this_thread;
1040 }
1041
1042
1043
1044 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1045 {
1046         int ret = 0;
1047
1048         /*
1049          * We pass this_thread into the thread as its args so that it can find out information
1050          * about itself and it has a bit of storage space for itself, not to mention that the REAL
1051          * thread function needs to finish off the setup of the structure
1052          */
1053         if ((ret = pthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1054         {
1055
1056                 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
1057                         strerror(ret));
1058                 return NULL;
1059         }
1060
1061
1062         num_threads++;  // Increase the count of threads in the system.
1063         if(this_thread->flags & CTDLTHREAD_WORKER)
1064                 num_workers++;
1065
1066         this_thread->next = CtdlThreadList;
1067         CtdlThreadList = this_thread;
1068         if (this_thread->next)
1069                 this_thread->next->prev = this_thread;
1070
1071         return this_thread;
1072 }
1073
1074
1075
1076 void ctdl_thread_internal_check_scheduled(void)
1077 {
1078         CtdlThreadNode *this_thread, *that_thread;
1079         time_t now;
1080
1081         if (try_critical_section(S_SCHEDULE_LIST))
1082                 return; /* If this list is locked we wait till the next chance */
1083
1084         now = time(NULL);
1085
1086 #ifdef WITH_THREADLOG
1087         CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1088 #endif
1089
1090         this_thread = CtdlThreadSchedList;
1091         while(this_thread)
1092         {
1093                 that_thread = this_thread;
1094                 this_thread = this_thread->next;
1095
1096                 if (now > that_thread->when)
1097                 {
1098                         /* Unlink from schedule list */
1099                         if (that_thread->prev)
1100                                 that_thread->prev->next = that_thread->next;
1101                         else
1102                                 CtdlThreadSchedList = that_thread->next;
1103                         if (that_thread->next)
1104                                 that_thread->next->prev = that_thread->prev;
1105
1106                         that_thread->next = that_thread->prev = NULL;
1107 #ifdef WITH_THREADLOG
1108                         CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1109 #endif
1110                         begin_critical_section(S_THREAD_LIST);
1111                         if (CT->state > CTDL_THREAD_STOP_REQ)
1112                         {       /* Only start it if the system is not stopping */
1113                                 pthread_mutex_lock(&that_thread->ThreadMutex);
1114                                 if (ctdl_thread_internal_start_scheduled (that_thread) == NULL)
1115                                 {
1116 #ifdef WITH_THREADLOG
1117                         CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\".\n", that_thread->name);
1118 #endif
1119                                         pthread_mutex_unlock(&that_thread->ThreadMutex);
1120                                         pthread_mutex_destroy(&(that_thread->ThreadMutex));
1121                                         pthread_cond_destroy(&(that_thread->ThreadCond));
1122                                         pthread_mutex_destroy(&(that_thread->SleepMutex));
1123                                         pthread_cond_destroy(&(that_thread->SleepCond));
1124                                         pthread_attr_destroy(&that_thread->attr);
1125                                         free(that_thread);
1126                                 }
1127                                 else
1128                                 {
1129                                         CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (%ld).\n",
1130                                                 that_thread->name, that_thread->tid);
1131                                         pthread_mutex_unlock(&that_thread->ThreadMutex);
1132                                         ctdl_thread_internal_calc_loadavg();
1133                                 }
1134                         }
1135                         end_critical_section(S_THREAD_LIST);
1136                 }
1137                 else
1138                 {
1139 #ifdef WITH_THREADLOG
1140                         CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n", that_thread->name, that_thread->when - time(NULL));
1141 #endif
1142                 }
1143         }
1144         end_critical_section(S_SCHEDULE_LIST);
1145 }
1146
1147
1148 /*
1149  * A warapper function for select so we can show a thread as blocked
1150  */
1151 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1152 {
1153         int ret;
1154
1155         ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1156         ret = select(n, readfds, writefds, exceptfds, timeout);
1157         ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1158         return ret;
1159 }
1160
1161
1162
1163 void *new_worker_thread(void *arg);
1164 extern void close_masters (void);
1165
1166
1167
1168 void go_threading(void)
1169 {
1170         int i;
1171         CtdlThreadNode *last_worker;
1172
1173         /*
1174          * Initialise the thread system
1175          */
1176         ctdl_thread_internal_init();
1177
1178         /* Second call to module init functions now that threading is up */
1179         initialise_modules(1);
1180
1181         /*
1182          * This thread is now used for garbage collection of other threads in the thread list
1183          */
1184         CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", pthread_self());
1185
1186         /*
1187          * We do a lot of locking and unlocking of the thread list in here.
1188          * We do this so that we can repeatedly release time for other threads
1189          * that may be waiting on the thread list.
1190          * We are a low priority thread so we can afford to do this
1191          */
1192
1193         while (CtdlThreadGetCount())
1194         {
1195                 if (CT->signal)
1196                         exit_signal = CT->signal;
1197                 if (exit_signal)
1198                 {
1199                         CtdlThreadStopAll();
1200 //                      close_masters();
1201                 }
1202                 check_sched_shutdown();
1203                 if (CT->state > CTDL_THREAD_STOP_REQ)
1204                 {
1205                         begin_critical_section(S_THREAD_LIST);
1206                         ctdl_thread_internal_calc_loadavg();
1207                         end_critical_section(S_THREAD_LIST);
1208
1209                         ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1210                 }
1211
1212                 /* Reduce the size of the worker thread pool if necessary. */
1213                 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1214                 {
1215                         /* Ask a worker thread to stop as we no longer need it */
1216                         begin_critical_section(S_THREAD_LIST);
1217                         last_worker = CtdlThreadList;
1218                         while (last_worker)
1219                         {
1220                                 pthread_mutex_lock(&last_worker->ThreadMutex);
1221                                 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1222                                 {
1223                                         pthread_mutex_unlock(&last_worker->ThreadMutex);
1224                                         break;
1225                                 }
1226                                 pthread_mutex_unlock(&last_worker->ThreadMutex);
1227                                 last_worker = last_worker->next;
1228                         }
1229                         end_critical_section(S_THREAD_LIST);
1230                         if (last_worker)
1231                         {
1232 #ifdef WITH_THREADLOG
1233                                 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (%ld).\n",
1234                                         last_worker->name,
1235                                         last_worker->tid
1236                                         );
1237 #endif
1238                                 CtdlThreadStop(last_worker);
1239                         }
1240                 }
1241
1242                 /*
1243                  * If all our workers are working hard, start some more to help out
1244                  * with things
1245                  */
1246                 /* FIXME: come up with a better way to dynamically alter the number of threads
1247                  * based on the system load
1248                  */
1249 #ifdef NEW_WORKER
1250                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkers() <= num_sessions) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1251 #else
1252                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60) && (CtdlThreadGetLoadAvg() < 90) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1253 #endif /* NEW_WORKER */
1254                 {
1255                         for (i=0; i<5 ; i++)
1256                         {
1257 #ifdef NEW_WORKER
1258                                 CtdlThreadCreate("Worker Thread",
1259                                         CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1260                                         new_worker_thread,
1261                                         NULL
1262                                         );
1263 #else
1264                                 CtdlThreadCreate("Worker Thread",
1265                                         CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1266                                         worker_thread,
1267                                         NULL
1268                                         );
1269 #endif /* NEW_WORKER */
1270                         }
1271                 }
1272
1273                 CtdlThreadGC();
1274
1275                 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1276                 {
1277                         CtdlThreadGC();
1278                 }
1279
1280                 if (CtdlThreadGetCount())
1281                         CtdlThreadSleep(1);
1282         }
1283         /*
1284          * If the above loop exits we must be shutting down since we obviously have no threads
1285          */
1286         ctdl_thread_internal_cleanup();
1287 }
1288
1289
1290
1291
1292 /*
1293  * Starting a new implimentation of a worker thread.
1294  * This new implimentation will be faster and do more work per thread.
1295  */
1296
1297 /*
1298  * Select on master socket.
1299  * First worker thread in here acquires the lock and builds an FDSET of master sockets.
1300  * then it goes into a loop selecting on the master sockets timing out every few milliseconds.
1301  * If it times out it rebiulds its list and loops.
1302  * If the select succeeds it creates a new context and returns.
1303  * During this time the other workers are selecting on existing contexts or sleeping.
1304  */
1305 void select_on_master(void)
1306 {
1307         fd_set readfds;
1308         struct ServiceFunctionHook *serviceptr;
1309         int ssock;                      /* Descriptor for client socket */
1310         int highest;
1311         int m, i;
1312         int retval = 0;
1313         struct timeval tv;
1314         struct CitContext *con;
1315         const char *old_name;
1316
1317
1318
1319         old_name = CtdlThreadName("select_on_master");
1320
1321         /* Initialize the fdset. */
1322         FD_ZERO(&readfds);
1323         highest = 0;
1324
1325         /* First, add the various master sockets to the fdset. */
1326         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1327                 m = serviceptr->msock;
1328                 FD_SET(m, &readfds);
1329                 if (m > highest) {
1330                         highest = m;
1331                 }
1332         }
1333
1334         tv.tv_sec = 1;          /* wake up every 1 sec if no input */
1335         tv.tv_usec = 0;
1336         retval = CtdlThreadSelect(highest + 1, &readfds, NULL, NULL, &tv);
1337
1338         /* Select got an error or we are shutting down so get out */
1339         if (retval == 0 || CtdlThreadCheckStop()) {
1340                 CtdlThreadName(old_name);
1341                 return;
1342         }
1343
1344         /* Select says something happened on one of our master sockets so now we handle it */
1345         for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1346                 if (FD_ISSET(serviceptr->msock, &readfds)) {
1347                         ssock = accept(serviceptr->msock, NULL, 0);
1348                         if (ssock >= 0) {
1349                                 CtdlLogPrintf(CTDL_DEBUG, "New client socket %d\n", ssock);
1350                                 /* The master socket is non-blocking but the client
1351                                  * sockets need to be blocking, otherwise certain
1352                                  * operations barf on FreeBSD.  Not a fatal error.
1353                                  */
1354                                 if (fcntl(ssock, F_SETFL, 0) < 0) {
1355                                         CtdlLogPrintf(CTDL_EMERG,
1356                                                       "citserver: Can't set socket to blocking: %s\n",
1357                                                       strerror(errno));
1358                                 }
1359
1360                                 /* New context will be created already
1361                                  * set up in the CON_EXECUTING state.
1362                                  */
1363                                 con = CreateNewContext();
1364                                 CT->Context = con;
1365
1366                                 /* Assign our new socket number to it. */
1367                                 con->client_socket = ssock;
1368                                 con->h_command_function = serviceptr->h_command_function;
1369                                 con->h_async_function = serviceptr->h_async_function;
1370                                 con->ServiceName = serviceptr->ServiceName;
1371                                 /* Determine whether it's a local socket */
1372                                 if (serviceptr->sockpath != NULL)
1373                                         con->is_local_socket = 1;
1374
1375                                 /* Set the SO_REUSEADDR socket option */
1376                                 i = 1;
1377                                 setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
1378
1379                                 become_session(con);
1380                                 begin_session(con);
1381                                 serviceptr->h_greeting_function();
1382                                 become_session(NULL);
1383                                 con->state = CON_IDLE;
1384                                 break;
1385                         }
1386                 }
1387         }
1388
1389         CtdlThreadName(old_name);
1390 }
1391
1392 /*
1393  * Select on client socket.
1394  * First worker thread in here acquires the lock and builds an FDSET of client sockets.
1395  * then it selects on the client sockets timing out after 1 second.
1396  * If it times out the thread goes off to check on housekeeping etc.
1397  * If the select succeeds the thread goes off to handle the client request.
1398  * If the list of client connections is empty the threads all sleep for one second
1399  */
1400 struct CitContext *select_on_client(void)
1401 {
1402         fd_set readfds;
1403         struct timeval tv;
1404         int retval = 0;
1405         int highest=0;
1406         const char *old_name;
1407
1408
1409         old_name = CtdlThreadName("select_on_client");
1410
1411         /* Initialise the fdset */
1412         FD_ZERO(&readfds);
1413         FD_SET(CT->Context->client_socket, &readfds);
1414         highest = CT->Context->client_socket;
1415         /* Now we can select on any connections that are waiting */
1416
1417         if (!CtdlThreadCheckStop())
1418         {
1419                 tv.tv_sec = config.c_sleeping;          /* wake up every second if no input */
1420                 tv.tv_usec = 0;
1421                 retval = select(highest + 1, &readfds, NULL, NULL, &tv);
1422         }
1423         else    /* Shutting down? */
1424         {
1425                 CtdlThreadName(old_name);
1426                 return(NULL);
1427         }
1428
1429
1430         /* Now figure out who made this select() unblock.
1431          * First, check for an error or exit condition.
1432          */
1433         if (retval < 0) {
1434                 if (errno == EBADF) {
1435                         CtdlLogPrintf(CTDL_NOTICE, "select() failed: (%s)\n",
1436                                 strerror(errno));
1437                 }
1438                 if (errno != EINTR) {
1439                         CtdlLogPrintf(CTDL_EMERG, "Exiting (%s)\n", strerror(errno));
1440                         CtdlThreadStopAll();
1441                 } else if (!CtdlThreadCheckStop()) {
1442                         CtdlLogPrintf(CTDL_DEBUG, "Un handled select failure.\n");
1443                 }
1444                 CtdlThreadName(old_name);
1445                 return NULL;
1446         }
1447         else if(retval == 0)
1448         {
1449                 CtdlThreadName(old_name);
1450                 CT->Context->kill_me = 1;
1451                 CT->Context = NULL;
1452                 return CT->Context;
1453         }
1454
1455         CT->Context->state = CON_EXECUTING;
1456         CT->Context->input_waiting = 1;
1457
1458         CtdlThreadName(old_name);
1459         return (CT->Context);
1460 }
1461
1462
1463
1464 /*
1465  * Do the worker threads work when needed
1466  */
1467 int execute_session(struct CitContext *bind_me)
1468 {
1469         int force_purge;
1470
1471         become_session(bind_me);
1472
1473         /* If the client has sent a command, execute it. */
1474         if (CC->input_waiting) {
1475                 CC->h_command_function();
1476                 CC->input_waiting = 0;
1477         }
1478
1479         /* If there are asynchronous messages waiting and the
1480          * client supports it, do those now */
1481         if ((CC->is_async) && (CC->async_waiting)
1482            && (CC->h_async_function != NULL)) {
1483                 CC->h_async_function();
1484                 CC->async_waiting = 0;
1485         }
1486
1487         force_purge = CC->kill_me;
1488         if (force_purge)
1489                 CT->Context = NULL;
1490         become_session(NULL);
1491         bind_me->state = CON_IDLE;
1492         return force_purge;
1493 }
1494
1495
1496
1497 extern void dead_session_purge(int force);
1498
1499 /*
1500  * A new worker_thread loop.
1501  */
1502
1503 void *new_worker_thread(void *arg)
1504 {
1505         struct CitContext *bind_me;
1506         int force_purge;
1507
1508         while (!CtdlThreadCheckStop()) {
1509
1510                 /* make doubly sure we're not holding any stale db handles
1511                  * which might cause a deadlock.
1512                  */
1513                 cdb_check_handles();
1514                 force_purge = 0;
1515                 bind_me = NULL;         /* Which session shall we handle? */
1516
1517                 if (CT->Context == NULL)
1518                         select_on_master();
1519                 if (CtdlThreadCheckStop())
1520                         break;
1521
1522                 if (CT->Context)
1523                         bind_me = select_on_client();
1524                 if (CtdlThreadCheckStop())
1525                         break;
1526
1527                 if (bind_me)
1528                         force_purge = execute_session(bind_me);
1529
1530                 dead_session_purge(force_purge);
1531                 if (CtdlThreadCheckStop())
1532                         break;
1533
1534                 do_housekeeping();
1535         }
1536         return NULL;
1537 }