2 * $Id: sysdep.c 5882 2007-12-13 19:46:05Z davew $
4 * Citadel "system dependent" stuff.
5 * See copyright.txt for copyright information.
7 * Here's where we have the Citadel thread implimentation
11 #include <sys/types.h>
13 #include <sys/socket.h>
17 #if TIME_WITH_SYS_TIME
18 # include <sys/time.h>
22 # include <sys/time.h>
29 #include "ctdl_module.h"
30 #include "modules_init.h"
31 #include "housekeeping.h"
33 #include "citserver.h"
34 #include "sysdep_decls.h"
37 * define this to use the new worker_thread method of handling connections
42 * New thread interface.
43 * To create a thread you must call one of the create thread functions.
44 * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
45 * struct CtdlThreadNode *node = NULL;
47 * If the thread is created *node will point to the thread control structure for the created thread.
48 * If the thread creation fails *node remains NULL
49 * Do not free the memory pointed to by *node, it doesn't belong to you.
50 * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
51 * remove the need for the calls to eCrashRegisterThread and friends
54 static int num_threads = 0; /* Current number of threads */
55 static int num_workers = 0; /* Current number of worker threads */
57 CtdlThreadNode *CtdlThreadList = NULL;
58 CtdlThreadNode *CtdlThreadSchedList = NULL;
60 static citthread_t GC_thread;
61 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
62 double CtdlThreadLoadAvg = 0;
63 double CtdlThreadWorkerAvg = 0;
64 citthread_key_t ThreadKey;
66 citthread_mutex_t Critters[MAX_SEMAPHORES]; /* Things needing locking */
70 void InitialiseSemaphores(void)
74 /* Set up a bunch of semaphores to be used for critical sections */
75 for (i=0; i<MAX_SEMAPHORES; ++i) {
76 citthread_mutex_init(&Critters[i], NULL);
84 * Obtain a semaphore lock to begin a critical section.
85 * but only if no one else has one
87 int try_critical_section(int which_one)
89 /* For all types of critical sections except those listed here,
90 * ensure nobody ever tries to do a critical section within a
91 * transaction; this could lead to deadlock.
93 if ( (which_one != S_FLOORCACHE)
94 #ifdef DEBUG_MEMORY_LEAKS
95 && (which_one != S_DEBUGMEMLEAKS)
97 && (which_one != S_RPLIST)
101 return (citthread_mutex_trylock(&Critters[which_one]));
106 * Obtain a semaphore lock to begin a critical section.
108 void begin_critical_section(int which_one)
110 /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
112 /* For all types of critical sections except those listed here,
113 * ensure nobody ever tries to do a critical section within a
114 * transaction; this could lead to deadlock.
116 if ( (which_one != S_FLOORCACHE)
117 #ifdef DEBUG_MEMORY_LEAKS
118 && (which_one != S_DEBUGMEMLEAKS)
120 && (which_one != S_RPLIST)
124 citthread_mutex_lock(&Critters[which_one]);
128 * Release a semaphore lock to end a critical section.
130 void end_critical_section(int which_one)
132 citthread_mutex_unlock(&Critters[which_one]);
137 * A function to destroy the TSD
139 static void ctdl_thread_internal_dest_tsd(void *arg)
149 * A function to initialise the thread TSD
151 void ctdl_thread_internal_init_tsd(void)
155 if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
156 lprintf(CTDL_EMERG, "citthread_key_create: %s\n",
163 * Ensure that we have a key for thread-specific data.
165 * This should be called immediately after startup by any thread
168 void CtdlThreadAllocTSD(void)
172 if (citthread_getspecific(ThreadKey) != NULL)
175 tsd = malloc(sizeof(ThreadTSD));
179 memset(tsd->cursors, 0, sizeof tsd->cursors);
182 citthread_setspecific(ThreadKey, tsd);
186 void ctdl_thread_internal_free_tsd(void)
188 ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
189 citthread_setspecific(ThreadKey, NULL);
193 void ctdl_thread_internal_cleanup(void)
196 CtdlThreadNode *this_thread, *that_thread;
198 for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
200 free (CtdlThreadStates[i]);
203 /* Clean up the scheduled thread list */
204 this_thread = CtdlThreadSchedList;
207 that_thread = this_thread;
208 this_thread = this_thread->next;
209 citthread_mutex_destroy(&that_thread->ThreadMutex);
210 citthread_cond_destroy(&that_thread->ThreadCond);
211 citthread_mutex_destroy(&that_thread->SleepMutex);
212 citthread_cond_destroy(&that_thread->SleepCond);
213 citthread_attr_destroy(&that_thread->attr);
216 ctdl_thread_internal_free_tsd();
219 void ctdl_thread_internal_init(void)
221 CtdlThreadNode *this_thread;
224 GC_thread = citthread_self();
225 CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
226 CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
227 CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
228 CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
229 CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
230 CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
231 CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
232 CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
233 CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
234 CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
236 /* Get ourself a thread entry */
237 this_thread = malloc(sizeof(CtdlThreadNode));
238 if (this_thread == NULL) {
239 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
242 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
243 memset (this_thread, 0, sizeof(CtdlThreadNode));
245 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
246 citthread_cond_init (&(this_thread->ThreadCond), NULL);
247 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
248 citthread_cond_init (&(this_thread->SleepCond), NULL);
250 /* We are garbage collector so create us as running */
251 this_thread->state = CTDL_THREAD_RUNNING;
253 if ((ret = citthread_attr_init(&this_thread->attr))) {
254 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
259 this_thread->name = "Garbage Collection Thread";
261 this_thread->tid = GC_thread;
264 num_threads++; // Increase the count of threads in the system.
266 this_thread->next = CtdlThreadList;
267 CtdlThreadList = this_thread;
268 if (this_thread->next)
269 this_thread->next->prev = this_thread;
270 /* Set up start times */
271 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
272 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
277 * A function to update a threads load averages
279 void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
281 struct timeval now, result;
282 double last_duration;
284 gettimeofday(&now, NULL);
285 timersub(&now, &(this_thread->last_state_change), &result);
286 /* I don't think these mutex's are needed here */
287 citthread_mutex_lock(&this_thread->ThreadMutex);
288 // result now has a timeval for the time we spent in the last state since we last updated
289 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
290 if (this_thread->state == CTDL_THREAD_SLEEPING)
291 this_thread->avg_sleeping += last_duration;
292 if (this_thread->state == CTDL_THREAD_RUNNING)
293 this_thread->avg_running += last_duration;
294 if (this_thread->state == CTDL_THREAD_BLOCKED)
295 this_thread->avg_blocked += last_duration;
296 memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
297 citthread_mutex_unlock(&this_thread->ThreadMutex);
301 * A function to chenge the state of a thread
303 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
306 * Wether we change state or not we need update the load values
308 ctdl_thread_internal_update_avgs(this_thread);
309 /* This mutex not needed here? */
310 citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
311 if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
312 this_thread->state = new_state;
313 if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
314 this_thread->state = new_state;
315 if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
316 this_thread->state = new_state;
317 citthread_mutex_unlock(&this_thread->ThreadMutex);
322 * A function to tell all threads to exit
324 void CtdlThreadStopAll(void)
326 //FIXME: The signalling of the condition should not be in the critical_section
327 // We need to build a list of threads we are going to signal and then signal them afterwards
329 CtdlThreadNode *this_thread;
331 begin_critical_section(S_THREAD_LIST);
332 this_thread = CtdlThreadList;
335 #ifdef THREADS_USESIGNALS
336 citthread_killl(this_thread->tid, SIGHUP);
338 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
339 citthread_cond_signal(&this_thread->ThreadCond);
340 citthread_cond_signal(&this_thread->SleepCond);
341 CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (%ld).\n", this_thread->name, this_thread->tid);
342 this_thread = this_thread->next;
344 end_critical_section(S_THREAD_LIST);
349 * A function to wake up all sleeping threads
351 void CtdlThreadWakeAll(void)
353 CtdlThreadNode *this_thread;
355 CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
357 begin_critical_section(S_THREAD_LIST);
358 this_thread = CtdlThreadList;
361 if (!this_thread->thread_func)
363 citthread_cond_signal(&this_thread->ThreadCond);
364 citthread_cond_signal(&this_thread->SleepCond);
366 this_thread = this_thread->next;
368 end_critical_section(S_THREAD_LIST);
373 * A function to return the number of threads running in the system
375 int CtdlThreadGetCount(void)
380 int CtdlThreadGetWorkers(void)
385 double CtdlThreadGetWorkerAvg(void)
389 begin_critical_section(S_THREAD_LIST);
390 ret = CtdlThreadWorkerAvg;
391 end_critical_section(S_THREAD_LIST);
395 double CtdlThreadGetLoadAvg(void)
399 begin_critical_section(S_THREAD_LIST);
400 ret = CtdlThreadLoadAvg;
401 end_critical_section(S_THREAD_LIST);
409 * A function to rename a thread
410 * Returns a const char *
412 const char *CtdlThreadName(const char *name)
414 const char *old_name;
418 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
429 * A function to force a thread to exit
431 void CtdlThreadCancel(CtdlThreadNode *thread)
433 CtdlThreadNode *this_thread;
438 this_thread = thread;
441 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
446 if (!this_thread->thread_func)
448 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
453 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
454 citthread_cancel(this_thread->tid);
459 * A function for a thread to check if it has been asked to stop
461 int CtdlThreadCheckStop(void)
467 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
474 #ifdef THREADS_USERSIGNALS
476 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
478 if(state == CTDL_THREAD_STOP_REQ)
480 CT->state = CTDL_THREAD_STOPPING;
483 else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
492 * A function to ask a thread to exit
493 * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
495 void CtdlThreadStop(CtdlThreadNode *thread)
497 CtdlThreadNode *this_thread;
502 this_thread = thread;
505 if (!(this_thread->thread_func))
506 return; // Don't stop garbage collector
507 #ifdef THREADS_USESIGNALS
508 citthread_kill(this_thread->tid, SIGHUP);
510 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
511 citthread_cond_signal(&this_thread->ThreadCond);
512 citthread_cond_signal(&this_thread->SleepCond);
516 * So we now have a sleep command that works with threads but it is in seconds
518 void CtdlThreadSleep(int secs)
520 struct timespec wake_time;
521 struct timeval time_now;
526 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
530 memset (&wake_time, 0, sizeof(struct timespec));
531 gettimeofday(&time_now, NULL);
532 wake_time.tv_sec = time_now.tv_sec + secs;
533 wake_time.tv_nsec = time_now.tv_usec * 10;
535 ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
537 citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
538 citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
539 citthread_mutex_unlock(&CT->ThreadMutex);
541 ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
546 * Routine to clean up our thread function on exit
548 static void ctdl_internal_thread_cleanup(void *arg)
551 * In here we were called by the current thread because it is exiting
552 * NB. WE ARE THE CURRENT THREAD
554 CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (%ld) exited.\n", CT->name, CT->tid);
556 #ifdef HAVE_BACKTRACE
557 eCrash_UnregisterThread();
560 citthread_mutex_lock(&CT->ThreadMutex);
561 CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
562 citthread_mutex_unlock(&CT->ThreadMutex);
566 * A quick function to show the load averages
568 void ctdl_thread_internal_calc_loadavg(void)
570 CtdlThreadNode *that_thread;
571 double load_avg, worker_avg;
574 that_thread = CtdlThreadList;
579 /* Update load averages */
580 ctdl_thread_internal_update_avgs(that_thread);
581 citthread_mutex_lock(&that_thread->ThreadMutex);
582 that_thread->load_avg = (that_thread->avg_sleeping + that_thread->avg_running) / (that_thread->avg_sleeping + that_thread->avg_running + that_thread->avg_blocked) * 100;
583 that_thread->avg_sleeping /= 2;
584 that_thread->avg_running /= 2;
585 that_thread->avg_blocked /= 2;
586 load_avg += that_thread->load_avg;
587 if (that_thread->flags & CTDLTHREAD_WORKER)
589 worker_avg += that_thread->load_avg;
592 #ifdef WITH_THREADLOG
593 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
596 CtdlThreadStates[that_thread->state],
597 that_thread->avg_sleeping,
598 that_thread->avg_running,
599 that_thread->avg_blocked,
600 that_thread->load_avg);
602 citthread_mutex_unlock(&that_thread->ThreadMutex);
603 that_thread = that_thread->next;
605 CtdlThreadLoadAvg = load_avg/num_threads;
606 CtdlThreadWorkerAvg = worker_avg/workers;
607 #ifdef WITH_THREADLOG
608 CtdlLogPrintf(CTDL_INFO, "System load average %.2f, workers averag %.2f, threads %d, workers %d, sessions %d\n", CtdlThreadLoadAvg, CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
614 * Garbage collection routine.
615 * Gets called by main() in a loop to clean up the thread list periodically.
617 void CtdlThreadGC (void)
619 CtdlThreadNode *this_thread, *that_thread;
620 int workers = 0, sys_workers;
623 begin_critical_section(S_THREAD_LIST);
625 /* Handle exiting of garbage collector thread */
627 CtdlThreadList->state = CTDL_THREAD_EXITED;
629 #ifdef WITH_THREADLOG
630 CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
633 * Woke up to do garbage collection
635 this_thread = CtdlThreadList;
638 that_thread = this_thread;
639 this_thread = this_thread->next;
641 /* Do we need to clean up this thread? */
642 if (that_thread->state != CTDL_THREAD_EXITED)
644 if(that_thread->flags & CTDLTHREAD_WORKER)
645 workers++; /* Sanity check on number of worker threads */
649 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
651 end_critical_section(S_THREAD_LIST);
652 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
657 if (num_threads <= 0)
659 end_critical_section(S_THREAD_LIST);
660 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
665 if(that_thread->flags & CTDLTHREAD_WORKER)
666 num_workers--; /* This is a wroker thread so reduce the count. */
668 /* If we are unlinking the list head then the next becomes the list head */
669 if(that_thread->prev)
670 that_thread->prev->next = that_thread->next;
672 CtdlThreadList = that_thread->next;
673 if(that_thread->next)
674 that_thread->next->prev = that_thread->prev;
676 citthread_cond_signal(&that_thread->ThreadCond);
677 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
678 citthread_mutex_lock(&that_thread->ThreadMutex); // Make sure it has done what its doing
679 citthread_mutex_unlock(&that_thread->ThreadMutex);
681 * Join on the thread to do clean up and prevent memory leaks
682 * Also makes sure the thread has cleaned up after itself before we remove it from the list
683 * We can join on the garbage collector thread the join should just return EDEADLCK
685 ret = citthread_join (that_thread->tid, NULL);
687 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
688 else if (ret == EINVAL)
689 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
690 else if (ret == ESRCH)
691 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
693 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error.\n");
695 * Now we own that thread entry
697 CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (%ld).\n", that_thread->name, that_thread->tid);
698 citthread_mutex_destroy(&that_thread->ThreadMutex);
699 citthread_cond_destroy(&that_thread->ThreadCond);
700 citthread_mutex_destroy(&that_thread->SleepMutex);
701 citthread_cond_destroy(&that_thread->SleepCond);
702 citthread_attr_destroy(&that_thread->attr);
705 sys_workers = num_workers;
706 end_critical_section(S_THREAD_LIST);
708 /* Sanity check number of worker threads */
709 if (workers != sys_workers)
711 CtdlLogPrintf(CTDL_EMERG,
712 "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
723 * Runtime function for a Citadel Thread.
724 * This initialises the threads environment and then calls the user supplied thread function
725 * Note that this is the REAL thread function and wraps the users thread function.
727 static void *ctdl_internal_thread_func (void *arg)
729 CtdlThreadNode *this_thread;
732 /* lock and unlock the thread list.
733 * This causes this thread to wait until all its creation stuff has finished before it
734 * can continue its execution.
736 begin_critical_section(S_THREAD_LIST);
737 this_thread = (CtdlThreadNode *) arg;
738 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
739 // citthread_mutex_lock(&this_thread->ThreadMutex);
741 // Register the cleanup function to take care of when we exit.
742 citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
743 // Get our thread data structure
744 CtdlThreadAllocTSD();
746 this_thread->pid = getpid();
747 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
748 /* Only change to running state if we weren't asked to stop during the create cycle
749 * Other wise there is a window to allow this threads creation to continue to full grown and
750 * therby prevent a shutdown of the server.
752 // citthread_mutex_unlock(&this_thread->ThreadMutex);
754 if (!CtdlThreadCheckStop())
756 citthread_mutex_lock(&this_thread->ThreadMutex);
757 this_thread->state = CTDL_THREAD_RUNNING;
758 citthread_mutex_unlock(&this_thread->ThreadMutex);
760 end_critical_section(S_THREAD_LIST);
762 // Register for tracing
763 #ifdef HAVE_BACKTRACE
764 eCrash_RegisterThread(this_thread->name, 0);
767 // Tell the world we are here
768 CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (%ld). \n", this_thread->name, this_thread->tid);
773 * run the thread to do the work but only if we haven't been asked to stop
775 if (!CtdlThreadCheckStop())
776 ret = (this_thread->thread_func)(this_thread->user_args);
779 * Our thread is exiting either because it wanted to end or because the server is stopping
780 * We need to clean up
782 citthread_cleanup_pop(1); // Execute our cleanup routine and remove it
791 * Function to initialise an empty thread structure
793 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
797 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
798 memset (this_thread, 0, sizeof(CtdlThreadNode));
800 /* Create the mutex's early so we can use them */
801 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
802 citthread_cond_init (&(this_thread->ThreadCond), NULL);
803 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
804 citthread_cond_init (&(this_thread->SleepCond), NULL);
806 this_thread->state = CTDL_THREAD_CREATE;
808 if ((ret = citthread_attr_init(&this_thread->attr))) {
809 citthread_mutex_unlock(&this_thread->ThreadMutex);
810 citthread_mutex_destroy(&(this_thread->ThreadMutex));
811 citthread_cond_destroy(&(this_thread->ThreadCond));
812 citthread_mutex_destroy(&(this_thread->SleepMutex));
813 citthread_cond_destroy(&(this_thread->SleepCond));
814 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
819 /* Our per-thread stacks need to be bigger than the default size,
820 * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
821 * crashes on 64-bit Linux.
823 if (flags & CTDLTHREAD_BIGSTACK)
825 #ifdef WITH_THREADLOG
826 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
828 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
829 citthread_mutex_unlock(&this_thread->ThreadMutex);
830 citthread_mutex_destroy(&(this_thread->ThreadMutex));
831 citthread_cond_destroy(&(this_thread->ThreadCond));
832 citthread_mutex_destroy(&(this_thread->SleepMutex));
833 citthread_cond_destroy(&(this_thread->SleepCond));
834 citthread_attr_destroy(&this_thread->attr);
835 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
842 /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
843 * load average for the system. If we don't do this then we create a mass of threads at the same time
844 * because the creation didn't affect the load average.
846 this_thread->avg_blocked = 2;
848 return (this_thread);
855 * Internal function to create a thread.
857 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
860 CtdlThreadNode *this_thread;
862 if (num_threads >= 32767)
864 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
868 this_thread = malloc(sizeof(CtdlThreadNode));
869 if (this_thread == NULL) {
870 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
874 /* Initialise the thread structure */
875 if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
878 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
882 * If we got here we are going to create the thread so we must initilise the structure
883 * first because most implimentations of threading can't create it in a stopped state
884 * and it might want to do things with its structure that aren't initialised otherwise.
888 this_thread->name = name;
892 this_thread->name = "Un-named Thread";
895 this_thread->flags = flags;
896 this_thread->thread_func = thread_func;
897 this_thread->user_args = args;
899 // citthread_mutex_lock(&this_thread->ThreadMutex);
901 begin_critical_section(S_THREAD_LIST);
903 * We pass this_thread into the thread as its args so that it can find out information
904 * about itself and it has a bit of storage space for itself, not to mention that the REAL
905 * thread function needs to finish off the setup of the structure
907 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
909 end_critical_section(S_THREAD_LIST);
910 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
912 citthread_mutex_unlock(&this_thread->ThreadMutex);
913 citthread_mutex_destroy(&(this_thread->ThreadMutex));
914 citthread_cond_destroy(&(this_thread->ThreadCond));
915 citthread_mutex_destroy(&(this_thread->SleepMutex));
916 citthread_cond_destroy(&(this_thread->SleepCond));
917 citthread_attr_destroy(&this_thread->attr);
922 num_threads++; // Increase the count of threads in the system.
923 if(this_thread->flags & CTDLTHREAD_WORKER)
926 this_thread->next = CtdlThreadList;
927 CtdlThreadList = this_thread;
928 if (this_thread->next)
929 this_thread->next->prev = this_thread;
930 ctdl_thread_internal_calc_loadavg();
932 // citthread_mutex_unlock(&this_thread->ThreadMutex);
933 end_critical_section(S_THREAD_LIST);
939 * Wrapper function to create a thread
940 * ensures the critical section and other protections are in place.
941 * char *name = name to give to thread, if NULL, use generic name
942 * int flags = flags to determine type of thread and standard facilities
944 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
946 CtdlThreadNode *ret = NULL;
948 ret = ctdl_internal_create_thread(name, flags, thread_func, args);
955 * Internal function to schedule a thread.
956 * Must be called from within a S_THREAD_LIST critical section
958 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
960 CtdlThreadNode *this_thread;
962 if (num_threads >= 32767)
964 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
968 this_thread = malloc(sizeof(CtdlThreadNode));
969 if (this_thread == NULL) {
970 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
973 /* Initialise the thread structure */
974 if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
977 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
982 * If we got here we are going to create the thread so we must initilise the structure
983 * first because most implimentations of threading can't create it in a stopped state
984 * and it might want to do things with its structure that aren't initialised otherwise.
988 this_thread->name = name;
992 this_thread->name = "Un-named Thread";
995 this_thread->flags = flags;
996 this_thread->thread_func = thread_func;
997 this_thread->user_args = args;
1000 * When to start this thread
1002 this_thread->when = when;
1004 begin_critical_section(S_SCHEDULE_LIST);
1005 this_thread->next = CtdlThreadSchedList;
1006 CtdlThreadSchedList = this_thread;
1007 if (this_thread->next)
1008 this_thread->next->prev = this_thread;
1009 end_critical_section(S_SCHEDULE_LIST);
1016 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1020 // citthread_mutex_lock(&that_thread->ThreadMutex);
1021 begin_critical_section(S_THREAD_LIST);
1023 * We pass this_thread into the thread as its args so that it can find out information
1024 * about itself and it has a bit of storage space for itself, not to mention that the REAL
1025 * thread function needs to finish off the setup of the structure
1027 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1029 end_critical_section(S_THREAD_LIST);
1030 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1031 // citthread_mutex_unlock(&this_thread->ThreadMutex);
1032 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1033 citthread_cond_destroy(&(this_thread->ThreadCond));
1034 citthread_mutex_destroy(&(this_thread->SleepMutex));
1035 citthread_cond_destroy(&(this_thread->SleepCond));
1036 citthread_attr_destroy(&this_thread->attr);
1042 num_threads++; // Increase the count of threads in the system.
1043 if(this_thread->flags & CTDLTHREAD_WORKER)
1046 this_thread->next = CtdlThreadList;
1047 CtdlThreadList = this_thread;
1048 if (this_thread->next)
1049 this_thread->next->prev = this_thread;
1050 // citthread_mutex_unlock(&that_thread->ThreadMutex);
1052 ctdl_thread_internal_calc_loadavg();
1053 end_critical_section(S_THREAD_LIST);
1061 void ctdl_thread_internal_check_scheduled(void)
1063 CtdlThreadNode *this_thread, *that_thread;
1066 if (try_critical_section(S_SCHEDULE_LIST))
1067 return; /* If this list is locked we wait till the next chance */
1071 #ifdef WITH_THREADLOG
1072 CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1075 this_thread = CtdlThreadSchedList;
1078 that_thread = this_thread;
1079 this_thread = this_thread->next;
1081 if (now > that_thread->when)
1083 /* Unlink from schedule list */
1084 if (that_thread->prev)
1085 that_thread->prev->next = that_thread->next;
1087 CtdlThreadSchedList = that_thread->next;
1088 if (that_thread->next)
1089 that_thread->next->prev = that_thread->prev;
1091 that_thread->next = that_thread->prev = NULL;
1092 #ifdef WITH_THREADLOG
1093 CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1095 if (CT->state > CTDL_THREAD_STOP_REQ)
1096 { /* Only start it if the system is not stopping */
1097 if (ctdl_thread_internal_start_scheduled (that_thread))
1099 #ifdef WITH_THREADLOG
1100 CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (%ud).\n",
1101 that_thread->name, that_thread->tid);
1106 #ifdef WITH_THREADLOG
1109 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n", that_thread->name, that_thread->when - time(NULL));
1113 end_critical_section(S_SCHEDULE_LIST);
1118 * A warapper function for select so we can show a thread as blocked
1120 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1124 ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1125 ret = select(n, readfds, writefds, exceptfds, timeout);
1126 ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1132 void *new_worker_thread(void *arg);
1133 extern void close_masters (void);
1137 void go_threading(void)
1140 CtdlThreadNode *last_worker;
1143 * Initialise the thread system
1145 ctdl_thread_internal_init();
1147 /* Second call to module init functions now that threading is up */
1148 initialise_modules(1);
1151 * This thread is now used for garbage collection of other threads in the thread list
1153 CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1156 * We do a lot of locking and unlocking of the thread list in here.
1157 * We do this so that we can repeatedly release time for other threads
1158 * that may be waiting on the thread list.
1159 * We are a low priority thread so we can afford to do this
1162 while (CtdlThreadGetCount())
1165 exit_signal = CT->signal;
1168 CtdlThreadStopAll();
1171 check_sched_shutdown();
1172 if (CT->state > CTDL_THREAD_STOP_REQ)
1174 begin_critical_section(S_THREAD_LIST);
1175 ctdl_thread_internal_calc_loadavg();
1176 end_critical_section(S_THREAD_LIST);
1178 ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1181 /* Reduce the size of the worker thread pool if necessary. */
1182 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1184 /* Ask a worker thread to stop as we no longer need it */
1185 begin_critical_section(S_THREAD_LIST);
1186 last_worker = CtdlThreadList;
1189 citthread_mutex_lock(&last_worker->ThreadMutex);
1190 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1192 citthread_mutex_unlock(&last_worker->ThreadMutex);
1195 citthread_mutex_unlock(&last_worker->ThreadMutex);
1196 last_worker = last_worker->next;
1198 end_critical_section(S_THREAD_LIST);
1201 #ifdef WITH_THREADLOG
1202 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (%ld).\n",
1207 CtdlThreadStop(last_worker);
1212 * If all our workers are working hard, start some more to help out
1215 /* FIXME: come up with a better way to dynamically alter the number of threads
1216 * based on the system load
1219 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkers() <= num_sessions) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1221 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60) && (CtdlThreadGetLoadAvg() < 90) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1222 #endif /* NEW_WORKER */
1224 for (i=0; i<5 ; i++)
1227 CtdlThreadCreate("Worker Thread (new)",
1228 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1233 CtdlThreadCreate("Worker Thread",
1234 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1238 #endif /* NEW_WORKER */
1244 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1249 if (CtdlThreadGetCount())
1253 * If the above loop exits we must be shutting down since we obviously have no threads
1255 ctdl_thread_internal_cleanup();
1262 * Starting a new implimentation of a worker thread.
1263 * This new implimentation will be faster and do more work per thread.
1267 * Select on master socket.
1268 * First worker thread in here acquires the lock and builds an FDSET of master sockets.
1269 * then it goes into a loop selecting on the master sockets timing out every few milliseconds.
1270 * If it times out it rebiulds its list and loops.
1271 * If the select succeeds it creates a new context and returns.
1272 * During this time the other workers are selecting on existing contexts or sleeping.
1274 void select_on_master(void)
1277 struct ServiceFunctionHook *serviceptr;
1278 int ssock; /* Descriptor for client socket */
1283 struct CitContext *con;
1284 const char *old_name;
1288 old_name = CtdlThreadName("select_on_master");
1290 /* Initialize the fdset. */
1294 /* First, add the various master sockets to the fdset. */
1295 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1296 m = serviceptr->msock;
1297 FD_SET(m, &readfds);
1303 tv.tv_sec = 1; /* wake up every 1 sec if no input */
1305 retval = CtdlThreadSelect(highest + 1, &readfds, NULL, NULL, &tv);
1307 /* Select got an error or we are shutting down so get out */
1308 if (retval == 0 || CtdlThreadCheckStop()) {
1309 CtdlThreadName(old_name);
1313 /* Select says something happened on one of our master sockets so now we handle it */
1314 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1315 if (FD_ISSET(serviceptr->msock, &readfds)) {
1316 ssock = accept(serviceptr->msock, NULL, 0);
1318 CtdlLogPrintf(CTDL_DEBUG, "New client socket %d\n", ssock);
1319 /* The master socket is non-blocking but the client
1320 * sockets need to be blocking, otherwise certain
1321 * operations barf on FreeBSD. Not a fatal error.
1323 if (fcntl(ssock, F_SETFL, 0) < 0) {
1324 CtdlLogPrintf(CTDL_EMERG,
1325 "citserver: Can't set socket to blocking: %s\n",
1329 /* New context will be created already
1330 * set up in the CON_EXECUTING state.
1332 con = CreateNewContext();
1335 /* Assign our new socket number to it. */
1336 con->client_socket = ssock;
1337 con->h_command_function = serviceptr->h_command_function;
1338 con->h_async_function = serviceptr->h_async_function;
1339 con->ServiceName = serviceptr->ServiceName;
1340 /* Determine whether it's a local socket */
1341 if (serviceptr->sockpath != NULL)
1342 con->is_local_socket = 1;
1344 /* Set the SO_REUSEADDR socket option */
1346 setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
1348 become_session(con);
1350 serviceptr->h_greeting_function();
1351 become_session(NULL);
1352 con->state = CON_IDLE;
1358 CtdlThreadName(old_name);
1362 * Select on client socket.
1363 * First worker thread in here acquires the lock and builds an FDSET of client sockets.
1364 * then it selects on the client sockets timing out after 1 second.
1365 * If it times out the thread goes off to check on housekeeping etc.
1366 * If the select succeeds the thread goes off to handle the client request.
1367 * If the list of client connections is empty the threads all sleep for one second
1369 struct CitContext *select_on_client(void)
1375 const char *old_name;
1378 old_name = CtdlThreadName("select_on_client");
1380 /* Initialise the fdset */
1382 FD_SET(CT->Context->client_socket, &readfds);
1383 highest = CT->Context->client_socket;
1384 /* Now we can select on any connections that are waiting */
1386 if (!CtdlThreadCheckStop())
1388 tv.tv_sec = config.c_sleeping; /* wake up every second if no input */
1390 retval = select(highest + 1, &readfds, NULL, NULL, &tv);
1392 else /* Shutting down? */
1394 CtdlThreadName(old_name);
1399 /* Now figure out who made this select() unblock.
1400 * First, check for an error or exit condition.
1403 if (errno == EBADF) {
1404 CtdlLogPrintf(CTDL_NOTICE, "select() failed: (%s)\n",
1407 if (errno != EINTR) {
1408 CtdlLogPrintf(CTDL_EMERG, "Exiting (%s)\n", strerror(errno));
1409 CtdlThreadStopAll();
1410 } else if (!CtdlThreadCheckStop()) {
1411 CtdlLogPrintf(CTDL_DEBUG, "Un handled select failure.\n");
1413 CtdlThreadName(old_name);
1416 else if(retval == 0)
1418 CtdlThreadName(old_name);
1419 CT->Context->kill_me = 1;
1424 CT->Context->state = CON_EXECUTING;
1425 CT->Context->input_waiting = 1;
1427 CtdlThreadName(old_name);
1428 return (CT->Context);
1434 * Do the worker threads work when needed
1436 int execute_session(struct CitContext *bind_me)
1440 become_session(bind_me);
1442 /* If the client has sent a command, execute it. */
1443 if (CC->input_waiting) {
1444 CC->h_command_function();
1445 CC->input_waiting = 0;
1448 /* If there are asynchronous messages waiting and the
1449 * client supports it, do those now */
1450 if ((CC->is_async) && (CC->async_waiting)
1451 && (CC->h_async_function != NULL)) {
1452 CC->h_async_function();
1453 CC->async_waiting = 0;
1456 force_purge = CC->kill_me;
1459 become_session(NULL);
1460 bind_me->state = CON_IDLE;
1466 extern void dead_session_purge(int force);
1469 * A new worker_thread loop.
1472 void *new_worker_thread(void *arg)
1474 struct CitContext *bind_me;
1477 while (!CtdlThreadCheckStop()) {
1479 /* make doubly sure we're not holding any stale db handles
1480 * which might cause a deadlock.
1482 cdb_check_handles();
1484 bind_me = NULL; /* Which session shall we handle? */
1486 if (CT->Context == NULL)
1488 if (CtdlThreadCheckStop())
1492 bind_me = select_on_client();
1493 if (CtdlThreadCheckStop())
1497 force_purge = execute_session(bind_me);
1499 dead_session_purge(force_purge);
1500 if (CtdlThreadCheckStop())