citadel/threads.c

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