citadel/threads.c

   1 /*
   2  * $Id$
   3  *
   4  * Citadel "system dependent" stuff.
   5  * See COPYING for copyright information.
   6  *
   7  * Here's where we have the Citadel thread implimentation
   8  *
   9  */
  10
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <stdio.h>
  14 #include <sys/types.h>
  15 #include <errno.h>
  16 #include <sys/socket.h>
  17 #include <unistd.h>
  18 #include <fcntl.h>
  19 #include <signal.h>
  20
  21 #include "sysdep.h"
  22 #if TIME_WITH_SYS_TIME
  23 # include <sys/time.h>
  24 # include <time.h>
  25 #else
  26 # if HAVE_SYS_TIME_H
  27 #  include <sys/time.h>
  28 # else
  29 #  include <time.h>
  30 # endif
  31 #endif
  32
  33 #ifdef HAVE_SYSCALL_H
  34 # include <syscall.h>
  35 #else
  36 # if HAVE_SYS_SYSCALL_H
  37 #  include <sys/syscall.h>
  38 # endif
  39 #endif
  40
  41 #include <libcitadel.h>
  42
  43 #include "threads.h"
  44 #include "ctdl_module.h"
  45 #include "modules_init.h"
  46 #include "housekeeping.h"
  47 #include "config.h"
  48 #include "citserver.h"
  49 #include "sysdep_decls.h"
  50 #include "context.h"
  51
  52 /*
  53  * define this to use the new worker_thread method of handling connections
  54  */
  55 //#define NEW_WORKER
  56
  57 /*
  58  * New thread interface.
  59  * To create a thread you must call one of the create thread functions.
  60  * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
  61  * struct CtdlThreadNode *node = NULL;
  62  * pass in &node
  63  * If the thread is created *node will point to the thread control structure for the created thread.
  64  * If the thread creation fails *node remains NULL
  65  * Do not free the memory pointed to by *node, it doesn't belong to you.
  66  * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
  67  * remove the need for the calls to eCrashRegisterThread and friends
  68  */
  69
  70 static int num_threads = 0;                     /* Current number of threads */
  71 static int num_workers = 0;                     /* Current number of worker threads */
  72 long statcount = 0;             /* are we doing a stats check? */
  73 static long stats_done = 0;
  74
  75 CtdlThreadNode *CtdlThreadList = NULL;
  76 CtdlThreadNode *CtdlThreadSchedList = NULL;
  77
  78 static CtdlThreadNode *GC_thread = NULL;
  79 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
  80 double CtdlThreadLoadAvg = 0;
  81 double CtdlThreadWorkerAvg = 0;
  82 citthread_key_t ThreadKey;
  83
  84 citthread_mutex_t Critters[MAX_SEMAPHORES];     /* Things needing locking */
  85
  86
  87
  88 void InitialiseSemaphores(void)
  89 {
  90         int i;
  91
  92         /* Set up a bunch of semaphores to be used for critical sections */
  93         for (i=0; i<MAX_SEMAPHORES; ++i) {
  94                 citthread_mutex_init(&Critters[i], NULL);
  95         }
  96 }
  97
  98
  99
 100
 101 /*
 102  * Obtain a semaphore lock to begin a critical section.
 103  * but only if no one else has one
 104  */
 105 int try_critical_section(int which_one)
 106 {
 107         /* For all types of critical sections except those listed here,
 108          * ensure nobody ever tries to do a critical section within a
 109          * transaction; this could lead to deadlock.
 110          */
 111         if (    (which_one != S_FLOORCACHE)
 112 #ifdef DEBUG_MEMORY_LEAKS
 113                 && (which_one != S_DEBUGMEMLEAKS)
 114 #endif
 115                 && (which_one != S_RPLIST)
 116         ) {
 117                 cdb_check_handles();
 118         }
 119         return (citthread_mutex_trylock(&Critters[which_one]));
 120 }
 121
 122
 123 /*
 124  * Obtain a semaphore lock to begin a critical section.
 125  */
 126 void begin_critical_section(int which_one)
 127 {
 128         /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
 129
 130         /* For all types of critical sections except those listed here,
 131          * ensure nobody ever tries to do a critical section within a
 132          * transaction; this could lead to deadlock.
 133          */
 134         if (    (which_one != S_FLOORCACHE)
 135 #ifdef DEBUG_MEMORY_LEAKS
 136                 && (which_one != S_DEBUGMEMLEAKS)
 137 #endif
 138                 && (which_one != S_RPLIST)
 139         ) {
 140                 cdb_check_handles();
 141         }
 142         citthread_mutex_lock(&Critters[which_one]);
 143 }
 144
 145 /*
 146  * Release a semaphore lock to end a critical section.
 147  */
 148 void end_critical_section(int which_one)
 149 {
 150         citthread_mutex_unlock(&Critters[which_one]);
 151 }
 152
 153
 154 /*
 155  * A function to destroy the TSD
 156  */
 157 static void ctdl_thread_internal_dest_tsd(void *arg)
 158 {
 159         if (arg != NULL) {
 160                 check_handles(arg);
 161                 free(arg);
 162         }
 163 }
 164
 165
 166 /*
 167  * A function to initialise the thread TSD
 168  */
 169 void ctdl_thread_internal_init_tsd(void)
 170 {
 171         int ret;
 172
 173         if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
 174                 CtdlLogPrintf(CTDL_EMERG, "citthread_key_create: %s\n", strerror(ret));
 175                 exit(CTDLEXIT_DB);
 176         }
 177 }
 178
 179 /*
 180  * Ensure that we have a key for thread-specific data.
 181  *
 182  * This should be called immediately after startup by any thread
 183  *
 184  */
 185 void CtdlThreadAllocTSD(void)
 186 {
 187         ThreadTSD *tsd;
 188
 189         if (citthread_getspecific(ThreadKey) != NULL)
 190                 return;
 191
 192         tsd = malloc(sizeof(ThreadTSD));
 193
 194         tsd->tid = NULL;
 195
 196         memset(tsd->cursors, 0, sizeof tsd->cursors);
 197         tsd->self = NULL;
 198
 199         citthread_setspecific(ThreadKey, tsd);
 200 }
 201
 202
 203 void ctdl_thread_internal_free_tsd(void)
 204 {
 205         ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
 206         citthread_setspecific(ThreadKey, NULL);
 207 }
 208
 209
 210 void ctdl_thread_internal_cleanup(void)
 211 {
 212         int i;
 213         CtdlThreadNode *this_thread, *that_thread;
 214
 215         for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
 216         {
 217                 free (CtdlThreadStates[i]);
 218         }
 219
 220         /* Clean up the scheduled thread list */
 221         this_thread = CtdlThreadSchedList;
 222         while (this_thread)
 223         {
 224                 that_thread = this_thread;
 225                 this_thread = this_thread->next;
 226                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 227                 citthread_cond_destroy(&that_thread->ThreadCond);
 228                 citthread_mutex_destroy(&that_thread->SleepMutex);
 229                 citthread_cond_destroy(&that_thread->SleepCond);
 230                 citthread_attr_destroy(&that_thread->attr);
 231                 free(that_thread);
 232         }
 233         ctdl_thread_internal_free_tsd();
 234 }
 235
 236 void ctdl_thread_internal_init(void)
 237 {
 238         CtdlThreadNode *this_thread;
 239         int ret = 0;
 240
 241         CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
 242         CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
 243         CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
 244         CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
 245         CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
 246         CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
 247         CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
 248         CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
 249         CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
 250         CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
 251
 252         /* Get ourself a thread entry */
 253         this_thread = malloc(sizeof(CtdlThreadNode));
 254         if (this_thread == NULL) {
 255                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 256                 return;
 257         }
 258         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 259         memset (this_thread, 0, sizeof(CtdlThreadNode));
 260
 261         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 262         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 263         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 264         citthread_cond_init (&(this_thread->SleepCond), NULL);
 265
 266         /* We are garbage collector so create us as running */
 267         this_thread->state = CTDL_THREAD_RUNNING;
 268
 269         if ((ret = citthread_attr_init(&this_thread->attr))) {
 270                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 271                 free(this_thread);
 272                 return;
 273         }
 274
 275         this_thread->name = "Garbage Collection Thread";
 276
 277         this_thread->tid = citthread_self();
 278         GC_thread = this_thread;
 279         CT = this_thread;
 280
 281         num_threads++;  // Increase the count of threads in the system.
 282
 283         this_thread->next = CtdlThreadList;
 284         CtdlThreadList = this_thread;
 285         if (this_thread->next)
 286                 this_thread->next->prev = this_thread;
 287         /* Set up start times */
 288         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 289         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 290 }
 291
 292
 293 /*
 294  * A function to update a threads load averages
 295  */
 296  void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
 297  {
 298         struct timeval now, result;
 299         double last_duration;
 300
 301         gettimeofday(&now, NULL);
 302         timersub(&now, &(this_thread->last_state_change), &result);
 303         /* I don't think these mutex's are needed here */
 304         citthread_mutex_lock(&this_thread->ThreadMutex);
 305         // result now has a timeval for the time we spent in the last state since we last updated
 306         last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
 307         if (this_thread->state == CTDL_THREAD_SLEEPING)
 308                 this_thread->avg_sleeping += last_duration;
 309         if (this_thread->state == CTDL_THREAD_RUNNING)
 310                 this_thread->avg_running += last_duration;
 311         if (this_thread->state == CTDL_THREAD_BLOCKED)
 312                 this_thread->avg_blocked += last_duration;
 313         memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
 314         citthread_mutex_unlock(&this_thread->ThreadMutex);
 315 }
 316
 317 /*
 318  * A function to chenge the state of a thread
 319  */
 320 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
 321 {
 322         /*
 323          * Wether we change state or not we need update the load values
 324          */
 325         ctdl_thread_internal_update_avgs(this_thread);
 326         /* This mutex not needed here? */
 327         citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
 328         if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
 329                 this_thread->state = new_state;
 330         if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
 331                 this_thread->state = new_state;
 332         if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
 333                 this_thread->state = new_state;
 334         citthread_mutex_unlock(&this_thread->ThreadMutex);
 335 }
 336
 337
 338 /*
 339  * A function to tell all threads to exit
 340  */
 341 void CtdlThreadStopAll(void)
 342 {
 343         /* First run any registered shutdown hooks.  This probably doesn't belong here. */
 344         PerformSessionHooks(EVT_SHUTDOWN);
 345
 346         //FIXME: The signalling of the condition should not be in the critical_section
 347         // We need to build a list of threads we are going to signal and then signal them afterwards
 348
 349         CtdlThreadNode *this_thread;
 350
 351         begin_critical_section(S_THREAD_LIST);
 352         this_thread = CtdlThreadList;
 353         // Ask the GC thread to stop first so everything knows we are shutting down.
 354         GC_thread->state = CTDL_THREAD_STOP_REQ;
 355         while(this_thread)
 356         {
 357                 if (!citthread_equal(this_thread->tid, GC_thread->tid))
 358                         citthread_kill(this_thread->tid, SIGHUP);
 359
 360                 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 361                 citthread_cond_signal(&this_thread->ThreadCond);
 362                 citthread_cond_signal(&this_thread->SleepCond);
 363                 this_thread->stop_ticker = time(NULL);
 364                 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
 365                         this_thread->name, this_thread->tid);
 366                 this_thread = this_thread->next;
 367         }
 368         end_critical_section(S_THREAD_LIST);
 369 }
 370
 371
 372 /*
 373  * A function to wake up all sleeping threads
 374  */
 375 void CtdlThreadWakeAll(void)
 376 {
 377         CtdlThreadNode *this_thread;
 378
 379         CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
 380
 381         begin_critical_section(S_THREAD_LIST);
 382         this_thread = CtdlThreadList;
 383         while(this_thread)
 384         {
 385                 if (!this_thread->thread_func)
 386                 {
 387                         citthread_cond_signal(&this_thread->ThreadCond);
 388                         citthread_cond_signal(&this_thread->SleepCond);
 389                 }
 390                 this_thread = this_thread->next;
 391         }
 392         end_critical_section(S_THREAD_LIST);
 393 }
 394
 395
 396 /*
 397  * A function to return the number of threads running in the system
 398  */
 399 int CtdlThreadGetCount(void)
 400 {
 401         return  num_threads;
 402 }
 403
 404 int CtdlThreadGetWorkers(void)
 405 {
 406         return  num_workers;
 407 }
 408
 409 double CtdlThreadGetWorkerAvg(void)
 410 {
 411         double ret;
 412
 413         begin_critical_section(S_THREAD_LIST);
 414         ret =  CtdlThreadWorkerAvg;
 415         end_critical_section(S_THREAD_LIST);
 416         return ret;
 417 }
 418
 419 double CtdlThreadGetLoadAvg(void)
 420 {
 421         double load_avg[3] = {0.0, 0.0, 0.0};
 422
 423         int ret = 0;
 424         int smp_num_cpus;
 425
 426         /* Borrowed this straight from procps */
 427         smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 428         if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
 429
 430 #ifdef HAVE_GETLOADAVG
 431         ret = getloadavg(load_avg, 3);
 432 #endif
 433         if (ret < 0)
 434                 return 0;
 435         return load_avg[0] / smp_num_cpus;
 436 /*
 437  * This old chunk of code return a value that indicated the load on citserver
 438  * This value could easily reach 100 % even when citserver was doing very little and
 439  * hence the machine has much more spare capacity.
 440  * Because this value was used to determine if the machine was under heavy load conditions
 441  * from other processes in the system then citserver could be strangled un-necesarily
 442  * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
 443  * So we have changed this.
 444
 445         begin_critical_section(S_THREAD_LIST);
 446         ret =  CtdlThreadLoadAvg;
 447         end_critical_section(S_THREAD_LIST);
 448         return ret;
 449 */
 450 }
 451
 452
 453
 454
 455 /*
 456  * A function to rename a thread
 457  * Returns a const char *
 458  */
 459 const char *CtdlThreadName(const char *name)
 460 {
 461         const char *old_name;
 462
 463         if (!CT)
 464         {
 465                 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
 466                 return NULL;
 467         }
 468         old_name = CT->name;
 469         if (name)
 470                 CT->name = name;
 471         return (old_name);
 472 }
 473
 474
 475 /*
 476  * A function to force a thread to exit
 477  */
 478 void CtdlThreadCancel(CtdlThreadNode *thread)
 479 {
 480         CtdlThreadNode *this_thread;
 481
 482         if (!thread)
 483                 this_thread = CT;
 484         else
 485                 this_thread = thread;
 486         if (!this_thread)
 487         {
 488                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
 489                 CtdlThreadStopAll();
 490                 return;
 491         }
 492
 493         if (!this_thread->thread_func)
 494         {
 495                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
 496                 CtdlThreadStopAll();
 497                 return;
 498         }
 499
 500         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
 501         citthread_cancel(this_thread->tid);
 502 }
 503
 504
 505 /*
 506  * A function for a thread to check if it has been asked to stop
 507  */
 508 int CtdlThreadCheckStop(void)
 509 {
 510         int state;
 511
 512         if (!CT)
 513         {
 514                 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
 515                 CtdlThreadStopAll();
 516                 return -1;
 517         }
 518
 519         state = CT->state;
 520
 521         if (CT->signal)
 522         {
 523                 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
 524                 if (CT->signal == SIGHUP)
 525                         CT->state = CTDL_THREAD_STOP_REQ;
 526                 CT->signal = 0;
 527         }
 528         if(state == CTDL_THREAD_STOP_REQ)
 529         {
 530                 CT->state = CTDL_THREAD_STOPPING;
 531                 return -1;
 532         }
 533         else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
 534         {
 535                 return -1;
 536         }
 537         return 0;
 538 }
 539
 540
 541 /*
 542  * A function to ask a thread to exit
 543  * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
 544  */
 545 void CtdlThreadStop(CtdlThreadNode *thread)
 546 {
 547         CtdlThreadNode *this_thread;
 548
 549         if (!thread)
 550                 this_thread = CT;
 551         else
 552                 this_thread = thread;
 553         if (!this_thread)
 554                 return;
 555         if (!(this_thread->thread_func))
 556                 return;         // Don't stop garbage collector
 557
 558         if (!citthread_equal(this_thread->tid, GC_thread->tid))
 559                 citthread_kill(this_thread->tid, SIGHUP);
 560
 561         ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
 562         citthread_cond_signal(&this_thread->ThreadCond);
 563         citthread_cond_signal(&this_thread->SleepCond);
 564         this_thread->stop_ticker = time(NULL);
 565 }
 566
 567 /*
 568  * So we now have a sleep command that works with threads but it is in seconds
 569  */
 570 void CtdlThreadSleep(int secs)
 571 {
 572         struct timespec wake_time;
 573         struct timeval time_now;
 574
 575
 576         if (!CT)
 577         {
 578                 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
 579                 return;
 580         }
 581
 582         memset (&wake_time, 0, sizeof(struct timespec));
 583         gettimeofday(&time_now, NULL);
 584         wake_time.tv_sec = time_now.tv_sec + secs;
 585         wake_time.tv_nsec = time_now.tv_usec * 10;
 586
 587         ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
 588
 589         citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
 590         citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
 591         citthread_mutex_unlock(&CT->ThreadMutex);
 592
 593         ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 594 }
 595
 596
 597 /*
 598  * Routine to clean up our thread function on exit
 599  */
 600 static void ctdl_internal_thread_cleanup(void *arg)
 601 {
 602         /*
 603          * In here we were called by the current thread because it is exiting
 604          * NB. WE ARE THE CURRENT THREAD
 605          */
 606         if (CT)
 607         {
 608                 const char *name = CT->name;
 609                 const pid_t tid = CT->tid;
 610
 611                 CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", name, tid);
 612         }
 613         else
 614         {
 615                 CtdlLogPrintf(CTDL_NOTICE, "some ((unknown ? ? ?) Thread exited.\n");
 616         }
 617
 618         #ifdef HAVE_BACKTRACE
 619 ///     eCrash_UnregisterThread();
 620         #endif
 621
 622         citthread_mutex_lock(&CT->ThreadMutex);
 623         CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
 624         citthread_mutex_unlock(&CT->ThreadMutex);
 625 }
 626
 627 /*
 628  * A quick function to show the load averages
 629  */
 630 void ctdl_thread_internal_calc_loadavg(void)
 631 {
 632         CtdlThreadNode *that_thread;
 633         double load_avg, worker_avg;
 634         int workers = 0;
 635
 636         that_thread = CtdlThreadList;
 637         load_avg = 0;
 638         worker_avg = 0;
 639         while(that_thread)
 640         {
 641                 /* Update load averages */
 642                 ctdl_thread_internal_update_avgs(that_thread);
 643                 citthread_mutex_lock(&that_thread->ThreadMutex);
 644                 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;
 645                 that_thread->avg_sleeping /= 2;
 646                 that_thread->avg_running /= 2;
 647                 that_thread->avg_blocked /= 2;
 648                 load_avg += that_thread->load_avg;
 649                 if (that_thread->flags & CTDLTHREAD_WORKER)
 650                 {
 651                         worker_avg += that_thread->load_avg;
 652                         workers++;
 653                 }
 654 #ifdef WITH_THREADLOG
 655                 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
 656                         that_thread->name,
 657                         that_thread->tid,
 658                         CtdlThreadStates[that_thread->state],
 659                         that_thread->avg_sleeping,
 660                         that_thread->avg_running,
 661                         that_thread->avg_blocked,
 662                         that_thread->load_avg);
 663 #endif
 664                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 665                 that_thread = that_thread->next;
 666         }
 667         CtdlThreadLoadAvg = load_avg/num_threads;
 668         CtdlThreadWorkerAvg = worker_avg/workers;
 669 #ifdef WITH_THREADLOG
 670         CtdlLogPrintf(CTDL_INFO, "System load average %.2f, workers averag %.2f, threads %d, workers %d, sessions %d\n", CtdlThreadGetLoadAvg(), CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
 671 #endif
 672 }
 673
 674
 675 /*
 676  * Garbage collection routine.
 677  * Gets called by main() in a loop to clean up the thread list periodically.
 678  */
 679 void CtdlThreadGC (void)
 680 {
 681         CtdlThreadNode *this_thread, *that_thread;
 682         int workers = 0, sys_workers;
 683         int ret=0;
 684
 685         begin_critical_section(S_THREAD_LIST);
 686
 687         /* Handle exiting of garbage collector thread */
 688         if(num_threads == 1)
 689                 CtdlThreadList->state = CTDL_THREAD_EXITED;
 690
 691 #ifdef WITH_THREADLOG
 692         CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
 693 #endif
 694         /*
 695          * Woke up to do garbage collection
 696          */
 697         this_thread = CtdlThreadList;
 698         while(this_thread)
 699         {
 700                 that_thread = this_thread;
 701                 this_thread = this_thread->next;
 702
 703                 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
 704                         && (!citthread_equal(that_thread->tid, citthread_self())))
 705                                 CtdlLogPrintf(CTDL_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
 706                 else
 707                 {
 708                         /**
 709                          * Catch the situation where a worker was asked to stop but couldn't and we are not
 710                          * shutting down.
 711                          */
 712                         that_thread->stop_ticker = 0;
 713                 }
 714
 715                 if (that_thread->stop_ticker + 5 == time(NULL))
 716                 {
 717                         CtdlLogPrintf(CTDL_DEBUG, "Thread System: The thread \"%s\" (0x%08lx) failed to self terminate within 5 ticks. It would be cancelled now.\n", that_thread->name, that_thread->tid);
 718                         if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
 719                                 CtdlLogPrintf(CTDL_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
 720 //                      that_thread->state = CTDL_THREAD_CANCELLED;
 721                         that_thread->stop_ticker++;
 722 //                      citthread_cancel(that_thread->tid);
 723 //                      continue;
 724                 }
 725
 726                 /* Do we need to clean up this thread? */
 727                 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
 728                 {
 729                         if(that_thread->flags & CTDLTHREAD_WORKER)
 730                                 workers++;      /* Sanity check on number of worker threads */
 731                         continue;
 732                 }
 733
 734                 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
 735                 {       /* Sanity check */
 736                         end_critical_section(S_THREAD_LIST);
 737                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
 738                         abort();
 739                         return;
 740                 }
 741
 742                 if (num_threads <= 0)
 743                 {       /* Sanity check */
 744                         end_critical_section(S_THREAD_LIST);
 745                         CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
 746                         abort();
 747                         return;
 748                 }
 749
 750                 if(that_thread->flags & CTDLTHREAD_WORKER)
 751                         num_workers--;  /* This is a wroker thread so reduce the count. */
 752                 num_threads--;
 753                 /* If we are unlinking the list head then the next becomes the list head */
 754                 if(that_thread->prev)
 755                         that_thread->prev->next = that_thread->next;
 756                 else
 757                         CtdlThreadList = that_thread->next;
 758                 if(that_thread->next)
 759                         that_thread->next->prev = that_thread->prev;
 760
 761                 citthread_cond_signal(&that_thread->ThreadCond);
 762                 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
 763                 citthread_mutex_lock(&that_thread->ThreadMutex);        // Make sure it has done what its doing
 764                 citthread_mutex_unlock(&that_thread->ThreadMutex);
 765                 /*
 766                  * Join on the thread to do clean up and prevent memory leaks
 767                  * Also makes sure the thread has cleaned up after itself before we remove it from the list
 768                  * We can join on the garbage collector thread the join should just return EDEADLCK
 769                  */
 770                 ret = citthread_join (that_thread->tid, NULL);
 771                 if (ret == EDEADLK)
 772                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
 773                 else if (ret == EINVAL)
 774                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
 775                 else if (ret == ESRCH)
 776                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
 777                 else if (ret != 0)
 778                         CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
 779                 /*
 780                  * Now we own that thread entry
 781                  */
 782                 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
 783                         that_thread->name, that_thread->tid);
 784                 citthread_mutex_destroy(&that_thread->ThreadMutex);
 785                 citthread_cond_destroy(&that_thread->ThreadCond);
 786                 citthread_mutex_destroy(&that_thread->SleepMutex);
 787                 citthread_cond_destroy(&that_thread->SleepCond);
 788                 citthread_attr_destroy(&that_thread->attr);
 789                 free(that_thread);
 790         }
 791         sys_workers = num_workers;
 792         end_critical_section(S_THREAD_LIST);
 793
 794         /* Sanity check number of worker threads */
 795         if (workers != sys_workers)
 796         {
 797                 CtdlLogPrintf(CTDL_EMERG,
 798                         "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
 799                         workers, sys_workers
 800                         );
 801                 abort();
 802         }
 803 }
 804
 805
 806
 807
 808 /*
 809  * Runtime function for a Citadel Thread.
 810  * This initialises the threads environment and then calls the user supplied thread function
 811  * Note that this is the REAL thread function and wraps the users thread function.
 812  */
 813 static void *ctdl_internal_thread_func (void *arg)
 814 {
 815         CtdlThreadNode *this_thread;
 816         void *ret = NULL;
 817
 818         /* lock and unlock the thread list.
 819          * This causes this thread to wait until all its creation stuff has finished before it
 820          * can continue its execution.
 821          */
 822         begin_critical_section(S_THREAD_LIST);
 823         this_thread = (CtdlThreadNode *) arg;
 824         gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
 825
 826         // Register the cleanup function to take care of when we exit.
 827         citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
 828         // Get our thread data structure
 829         CtdlThreadAllocTSD();
 830         CT = this_thread;
 831         this_thread->pid = getpid();
 832         memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
 833         /* Only change to running state if we weren't asked to stop during the create cycle
 834          * Other wise there is a window to allow this threads creation to continue to full grown and
 835          * therby prevent a shutdown of the server.
 836          */
 837         if (!CtdlThreadCheckStop())
 838         {
 839                 citthread_mutex_lock(&this_thread->ThreadMutex);
 840                 this_thread->state = CTDL_THREAD_RUNNING;
 841                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 842         }
 843         end_critical_section(S_THREAD_LIST);
 844
 845         // Register for tracing
 846         #ifdef HAVE_BACKTRACE
 847 ///     eCrash_RegisterThread(this_thread->name, 0);
 848         #endif
 849
 850         // Tell the world we are here
 851 #if defined(HAVE_SYSCALL_H) && defined (SYS_gettid)
 852         this_thread->reltid = syscall(SYS_gettid);
 853 #endif
 854         CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
 855                 this_thread->name, this_thread->tid);
 856
 857         /*
 858          * run the thread to do the work but only if we haven't been asked to stop
 859          */
 860         if (!CtdlThreadCheckStop())
 861                 ret = (this_thread->thread_func)(this_thread->user_args);
 862
 863         /*
 864          * Our thread is exiting either because it wanted to end or because the server is stopping
 865          * We need to clean up
 866          */
 867         citthread_cleanup_pop(1);       // Execute our cleanup routine and remove it
 868
 869         return(ret);
 870 }
 871
 872
 873
 874
 875 /*
 876  * Function to initialise an empty thread structure
 877  */
 878 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
 879 {
 880         int ret = 0;
 881
 882         // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
 883         memset (this_thread, 0, sizeof(CtdlThreadNode));
 884
 885         /* Create the mutex's early so we can use them */
 886         citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
 887         citthread_cond_init (&(this_thread->ThreadCond), NULL);
 888         citthread_mutex_init (&(this_thread->SleepMutex), NULL);
 889         citthread_cond_init (&(this_thread->SleepCond), NULL);
 890
 891         this_thread->state = CTDL_THREAD_CREATE;
 892
 893         if ((ret = citthread_attr_init(&this_thread->attr))) {
 894                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 895                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 896                 citthread_cond_destroy(&(this_thread->ThreadCond));
 897                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 898                 citthread_cond_destroy(&(this_thread->SleepCond));
 899                 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
 900                 free(this_thread);
 901                 return NULL;
 902         }
 903
 904         /* Our per-thread stacks need to be bigger than the default size,
 905          * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
 906          * crashes on 64-bit Linux.
 907          */
 908         if (flags & CTDLTHREAD_BIGSTACK)
 909         {
 910 #ifdef WITH_THREADLOG
 911                 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
 912 #endif
 913                 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
 914                         citthread_mutex_unlock(&this_thread->ThreadMutex);
 915                         citthread_mutex_destroy(&(this_thread->ThreadMutex));
 916                         citthread_cond_destroy(&(this_thread->ThreadCond));
 917                         citthread_mutex_destroy(&(this_thread->SleepMutex));
 918                         citthread_cond_destroy(&(this_thread->SleepCond));
 919                         citthread_attr_destroy(&this_thread->attr);
 920                         CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
 921                                 strerror(ret));
 922                         free(this_thread);
 923                         return NULL;
 924                 }
 925         }
 926
 927         /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
 928          * load average for the system. If we don't do this then we create a mass of threads at the same time
 929          * because the creation didn't affect the load average.
 930          */
 931         this_thread->avg_blocked = 2;
 932
 933         return (this_thread);
 934 }
 935
 936
 937
 938
 939 /*
 940  * Internal function to create a thread.
 941  */
 942 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
 943 {
 944         int ret = 0;
 945         CtdlThreadNode *this_thread;
 946
 947         if (num_threads >= 32767)
 948         {
 949                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
 950                 return NULL;
 951         }
 952
 953         this_thread = malloc(sizeof(CtdlThreadNode));
 954         if (this_thread == NULL) {
 955                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
 956                 return NULL;
 957         }
 958
 959         /* Initialise the thread structure */
 960         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
 961         {
 962                 free(this_thread);
 963                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
 964                 return NULL;
 965         }
 966         /*
 967          * If we got here we are going to create the thread so we must initilise the structure
 968          * first because most implimentations of threading can't create it in a stopped state
 969          * and it might want to do things with its structure that aren't initialised otherwise.
 970          */
 971         if(name)
 972         {
 973                 this_thread->name = name;
 974         }
 975         else
 976         {
 977                 this_thread->name = "Un-named Thread";
 978         }
 979
 980         this_thread->flags = flags;
 981         this_thread->thread_func = thread_func;
 982         this_thread->user_args = args;
 983
 984         begin_critical_section(S_THREAD_LIST);
 985         /*
 986          * We pass this_thread into the thread as its args so that it can find out information
 987          * about itself and it has a bit of storage space for itself, not to mention that the REAL
 988          * thread function needs to finish off the setup of the structure
 989          */
 990         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
 991         {
 992                 end_critical_section(S_THREAD_LIST);
 993                 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
 994                         strerror(ret));
 995                 citthread_mutex_unlock(&this_thread->ThreadMutex);
 996                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
 997                 citthread_cond_destroy(&(this_thread->ThreadCond));
 998                 citthread_mutex_destroy(&(this_thread->SleepMutex));
 999                 citthread_cond_destroy(&(this_thread->SleepCond));
1000                 citthread_attr_destroy(&this_thread->attr);
1001                 free(this_thread);
1002                 return NULL;
1003         }
1004         num_threads++;  // Increase the count of threads in the system.
1005         if(this_thread->flags & CTDLTHREAD_WORKER)
1006                 num_workers++;
1007
1008         this_thread->next = CtdlThreadList;
1009         CtdlThreadList = this_thread;
1010         if (this_thread->next)
1011                 this_thread->next->prev = this_thread;
1012         ctdl_thread_internal_calc_loadavg();
1013
1014         end_critical_section(S_THREAD_LIST);
1015
1016         return this_thread;
1017 }
1018
1019 /*
1020  * Wrapper function to create a thread
1021  * ensures the critical section and other protections are in place.
1022  * char *name = name to give to thread, if NULL, use generic name
1023  * int flags = flags to determine type of thread and standard facilities
1024  */
1025 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
1026 {
1027         CtdlThreadNode *ret = NULL;
1028
1029         ret = ctdl_internal_create_thread(name, flags, thread_func, args);
1030         return ret;
1031 }
1032
1033
1034
1035 /*
1036  * Internal function to schedule a thread.
1037  * Must be called from within a S_THREAD_LIST critical section
1038  */
1039 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
1040 {
1041         CtdlThreadNode *this_thread;
1042
1043         if (num_threads >= 32767)
1044         {
1045                 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
1046                 return NULL;
1047         }
1048
1049         this_thread = malloc(sizeof(CtdlThreadNode));
1050         if (this_thread == NULL) {
1051                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
1052                 return NULL;
1053         }
1054         /* Initialise the thread structure */
1055         if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
1056         {
1057                 free(this_thread);
1058                 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
1059                 return NULL;
1060         }
1061
1062         /*
1063          * If we got here we are going to create the thread so we must initilise the structure
1064          * first because most implimentations of threading can't create it in a stopped state
1065          * and it might want to do things with its structure that aren't initialised otherwise.
1066          */
1067         if(name)
1068         {
1069                 this_thread->name = name;
1070         }
1071         else
1072         {
1073                 this_thread->name = "Un-named Thread";
1074         }
1075
1076         this_thread->flags = flags;
1077         this_thread->thread_func = thread_func;
1078         this_thread->user_args = args;
1079
1080         /*
1081          * When to start this thread
1082          */
1083         this_thread->when = when;
1084
1085         begin_critical_section(S_SCHEDULE_LIST);
1086         this_thread->next = CtdlThreadSchedList;
1087         CtdlThreadSchedList = this_thread;
1088         if (this_thread->next)
1089                 this_thread->next->prev = this_thread;
1090         end_critical_section(S_SCHEDULE_LIST);
1091
1092         return this_thread;
1093 }
1094
1095
1096
1097 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1098 {
1099         int ret = 0;
1100
1101         begin_critical_section(S_THREAD_LIST);
1102         /*
1103          * We pass this_thread into the thread as its args so that it can find out information
1104          * about itself and it has a bit of storage space for itself, not to mention that the REAL
1105          * thread function needs to finish off the setup of the structure
1106          */
1107         if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1108         {
1109                 end_critical_section(S_THREAD_LIST);
1110                 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1111                 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1112                 citthread_cond_destroy(&(this_thread->ThreadCond));
1113                 citthread_mutex_destroy(&(this_thread->SleepMutex));
1114                 citthread_cond_destroy(&(this_thread->SleepCond));
1115                 citthread_attr_destroy(&this_thread->attr);
1116                 free(this_thread);
1117                 return NULL;
1118         }
1119
1120
1121         num_threads++;  // Increase the count of threads in the system.
1122         if(this_thread->flags & CTDLTHREAD_WORKER)
1123                 num_workers++;
1124
1125         this_thread->next = CtdlThreadList;
1126         CtdlThreadList = this_thread;
1127         if (this_thread->next)
1128                 this_thread->next->prev = this_thread;
1129
1130         ctdl_thread_internal_calc_loadavg();
1131         end_critical_section(S_THREAD_LIST);
1132
1133
1134         return this_thread;
1135 }
1136
1137
1138
1139 void ctdl_thread_internal_check_scheduled(void)
1140 {
1141         CtdlThreadNode *this_thread, *that_thread;
1142         time_t now;
1143
1144         /* Don't start scheduled threads if the system wants single user mode */
1145         if (CtdlWantSingleUser())
1146                 return;
1147
1148         if (try_critical_section(S_SCHEDULE_LIST))
1149                 return; /* If this list is locked we wait till the next chance */
1150
1151         now = time(NULL);
1152
1153 #ifdef WITH_THREADLOG
1154         CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1155 #endif
1156
1157         this_thread = CtdlThreadSchedList;
1158         while(this_thread)
1159         {
1160                 that_thread = this_thread;
1161                 this_thread = this_thread->next;
1162
1163                 if (now > that_thread->when)
1164                 {
1165                         /* Unlink from schedule list */
1166                         if (that_thread->prev)
1167                                 that_thread->prev->next = that_thread->next;
1168                         else
1169                                 CtdlThreadSchedList = that_thread->next;
1170                         if (that_thread->next)
1171                                 that_thread->next->prev = that_thread->prev;
1172
1173                         that_thread->next = that_thread->prev = NULL;
1174 #ifdef WITH_THREADLOG
1175                         CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1176 #endif
1177                         if (CT->state > CTDL_THREAD_STOP_REQ)
1178                         {       /* Only start it if the system is not stopping */
1179                                 if (ctdl_thread_internal_start_scheduled (that_thread))
1180                                 {
1181 #ifdef WITH_THREADLOG
1182                                         CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
1183                                                 that_thread->name, that_thread->tid);
1184 #endif
1185                                 }
1186                         }
1187                 }
1188 #ifdef WITH_THREADLOG
1189                 else
1190                 {
1191                         CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1192                                 that_thread->name, that_thread->when - time(NULL));
1193                 }
1194 #endif
1195         }
1196         end_critical_section(S_SCHEDULE_LIST);
1197 }
1198
1199
1200 /*
1201  * A warapper function for select so we can show a thread as blocked
1202  */
1203 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1204 {
1205         int ret = 0;
1206
1207         ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1208         if (!CtdlThreadCheckStop())
1209                 ret = select(n, readfds, writefds, exceptfds, timeout);
1210         /**
1211          * If the select returned <= 0 then it failed due to an error
1212          * or timeout so this thread could stop if asked to do so.
1213          * Anything else means it needs to continue unless the system is shutting down
1214          */
1215         if (ret > 0)
1216         {
1217                 /**
1218                  * The select says this thread needs to do something useful.
1219                  * This thread was in an idle state so it may have been asked to stop
1220                  * but if the system isn't shutting down this thread is no longer
1221                  * idle and select has given it a task to do so it must not stop
1222                  * In this condition we need to force it into the running state.
1223                  * CtdlThreadGC will clear its ticker for us.
1224                  *
1225                  * FIXME: there is still a small hole here. It is possible for the sequence of locking
1226                  * to allow the state to get changed to STOP_REQ just after this code if the other thread
1227                  * has decided to change the state before this lock, it there fore has to wait till the lock
1228                  * completes but it will continue to change the state. We need something a bit better here.
1229                  */
1230                 citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1231                 if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
1232                 {
1233                         CtdlLogPrintf(CTDL_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
1234                         CT->state = CTDL_THREAD_RUNNING;
1235                 }
1236                 citthread_mutex_unlock(&CT->ThreadMutex);
1237         }
1238
1239         ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1240
1241         return ret;
1242 }
1243
1244
1245
1246 void *new_worker_thread(void *arg);
1247 extern void close_masters (void);
1248
1249
1250 void *simulation_worker (void*arg) {
1251         struct CitContext *this;
1252
1253         this = CreateNewContext();
1254         CtdlThreadSleep(1);
1255         this->kill_me = 1;
1256         this->state = CON_IDLE;
1257         dead_session_purge(1);
1258         begin_critical_section(S_SESSION_TABLE);
1259         stats_done++;
1260         end_critical_section(S_SESSION_TABLE);
1261         return NULL;
1262 }
1263
1264
1265 void *simulation_thread (void *arg)
1266 {
1267         long stats = statcount;
1268
1269         while(stats && !CtdlThreadCheckStop()) {
1270                 CtdlThreadCreate("Connection simulation worker", CTDLTHREAD_BIGSTACK, simulation_worker, NULL);
1271                 stats--;
1272         }
1273         CtdlThreadStopAll();
1274         return NULL;
1275 }
1276
1277 void go_threading(void)
1278 {
1279         int i;
1280         CtdlThreadNode *last_worker;
1281         struct timeval start, now, result;
1282         double last_duration;
1283
1284         /*
1285          * Initialise the thread system
1286          */
1287         ctdl_thread_internal_init();
1288
1289         /* Second call to module init functions now that threading is up */
1290         if (!statcount) {
1291                 initialise_modules(1);
1292                 CtdlThreadCreate("select_on_master", CTDLTHREAD_BIGSTACK, select_on_master, NULL);
1293         }
1294         else {
1295                 CtdlLogPrintf(CTDL_EMERG, "Running connection simulation stats\n");
1296                 gettimeofday(&start, NULL);
1297                 CtdlThreadCreate("Connection simulation master", CTDLTHREAD_BIGSTACK, simulation_thread, NULL);
1298         }
1299
1300
1301         /*
1302          * This thread is now used for garbage collection of other threads in the thread list
1303          */
1304         CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1305
1306         /*
1307          * We do a lot of locking and unlocking of the thread list in here.
1308          * We do this so that we can repeatedly release time for other threads
1309          * that may be waiting on the thread list.
1310          * We are a low priority thread so we can afford to do this
1311          */
1312
1313         while (CtdlThreadGetCount())
1314         {
1315                 if (CT->signal)
1316                         exit_signal = CT->signal;
1317                 if (exit_signal)
1318                 {
1319                         CtdlThreadStopAll();
1320                 }
1321                 check_sched_shutdown();
1322                 if (CT->state > CTDL_THREAD_STOP_REQ)
1323                 {
1324                         begin_critical_section(S_THREAD_LIST);
1325                         ctdl_thread_internal_calc_loadavg();
1326                         end_critical_section(S_THREAD_LIST);
1327
1328                         ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1329                 }
1330
1331                 /* Reduce the size of the worker thread pool if necessary. */
1332                 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1333                 {
1334                         /* Ask a worker thread to stop as we no longer need it */
1335                         begin_critical_section(S_THREAD_LIST);
1336                         last_worker = CtdlThreadList;
1337                         while (last_worker)
1338                         {
1339                                 citthread_mutex_lock(&last_worker->ThreadMutex);
1340                                 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1341                                 {
1342                                         citthread_mutex_unlock(&last_worker->ThreadMutex);
1343                                         break;
1344                                 }
1345                                 citthread_mutex_unlock(&last_worker->ThreadMutex);
1346                                 last_worker = last_worker->next;
1347                         }
1348                         end_critical_section(S_THREAD_LIST);
1349                         if (last_worker)
1350                         {
1351 #ifdef WITH_THREADLOG
1352                                 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1353                                         last_worker->name,
1354                                         last_worker->tid
1355                                         );
1356 #endif
1357                                 CtdlThreadStop(last_worker);
1358                         }
1359                 }
1360
1361                 /*
1362                  * If all our workers are working hard, start some more to help out
1363                  * with things
1364                  */
1365                 /* FIXME: come up with a better way to dynamically alter the number of threads
1366                  * based on the system load
1367                  */
1368                 if (!statcount) {
1369                 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60)) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1370                 {
1371                         /* Only start new threads if we are not going to overload the machine */
1372                         /* Temporarily set to 10 should be enough to make sure we don't stranglew the server
1373                          * at least until we make this a config option */
1374                         if (CtdlThreadGetLoadAvg() < ((double)10.00)) {
1375                                 for (i=0; i<5 ; i++) {
1376                                         CtdlThreadCreate("Worker Thread",
1377                                                 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1378                                                 worker_thread,
1379                                                 NULL
1380                                                 );
1381                                 }
1382                         }
1383                         else
1384                                 CtdlLogPrintf (CTDL_WARNING, "Server strangled due to machine load average too high.\n");
1385                 }
1386                 }
1387
1388                 CtdlThreadGC();
1389
1390                 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1391                 {
1392                         CtdlThreadGC();
1393                 }
1394
1395 #ifdef THREADS_USESIGNALS
1396                 if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
1397 #else
1398                 if (CtdlThreadGetCount())
1399 #endif
1400                         CtdlThreadSleep(1);
1401         }
1402         /*
1403          * If the above loop exits we must be shutting down since we obviously have no threads
1404          */
1405         ctdl_thread_internal_cleanup();
1406
1407         if (statcount) {
1408                 gettimeofday(&now, NULL);
1409                 timersub(&now, &start, &result);
1410                 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
1411                 CtdlLogPrintf(CTDL_EMERG, "Simulated %ld connections in %f seconds\n", stats_done, last_duration);
1412         }
1413 }
1414
1415
1416
1417