citadel/threads.c

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