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
12 #include <sys/socket.h>
16 #if TIME_WITH_SYS_TIME
17 # include <sys/time.h>
21 # include <sys/time.h>
28 #include "ctdl_module.h"
29 #include "modules_init.h"
30 #include "housekeeping.h"
32 #include "citserver.h"
33 #include "sysdep_decls.h"
36 * define this to use the new worker_thread method of handling connections
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;
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
53 static int num_threads = 0; /* Current number of threads */
54 static int num_workers = 0; /* Current number of worker threads */
56 CtdlThreadNode *CtdlThreadList = NULL;
57 CtdlThreadNode *CtdlThreadSchedList = NULL;
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;
65 citthread_mutex_t Critters[MAX_SEMAPHORES]; /* Things needing locking */
69 void InitialiseSemaphores(void)
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);
83 * Obtain a semaphore lock to begin a critical section.
84 * but only if no one else has one
86 int try_critical_section(int which_one)
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.
92 if ( (which_one != S_FLOORCACHE)
93 #ifdef DEBUG_MEMORY_LEAKS
94 && (which_one != S_DEBUGMEMLEAKS)
96 && (which_one != S_RPLIST)
100 return (citthread_mutex_trylock(&Critters[which_one]));
105 * Obtain a semaphore lock to begin a critical section.
107 void begin_critical_section(int which_one)
109 /* CtdlLogPrintf(CTDL_DEBUG, "begin_critical_section(%d)\n", which_one); */
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.
115 if ( (which_one != S_FLOORCACHE)
116 #ifdef DEBUG_MEMORY_LEAKS
117 && (which_one != S_DEBUGMEMLEAKS)
119 && (which_one != S_RPLIST)
123 citthread_mutex_lock(&Critters[which_one]);
127 * Release a semaphore lock to end a critical section.
129 void end_critical_section(int which_one)
131 citthread_mutex_unlock(&Critters[which_one]);
136 * A function to destroy the TSD
138 static void ctdl_thread_internal_dest_tsd(void *arg)
148 * A function to initialise the thread TSD
150 void ctdl_thread_internal_init_tsd(void)
154 if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
155 lprintf(CTDL_EMERG, "citthread_key_create: %s\n",
162 * Ensure that we have a key for thread-specific data.
164 * This should be called immediately after startup by any thread
167 void CtdlThreadAllocTSD(void)
171 if (citthread_getspecific(ThreadKey) != NULL)
174 tsd = malloc(sizeof(ThreadTSD));
178 memset(tsd->cursors, 0, sizeof tsd->cursors);
181 citthread_setspecific(ThreadKey, tsd);
185 void ctdl_thread_internal_free_tsd(void)
187 ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
188 citthread_setspecific(ThreadKey, NULL);
192 void ctdl_thread_internal_cleanup(void)
195 CtdlThreadNode *this_thread, *that_thread;
197 for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
199 free (CtdlThreadStates[i]);
202 /* Clean up the scheduled thread list */
203 this_thread = CtdlThreadSchedList;
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);
215 ctdl_thread_internal_free_tsd();
218 void ctdl_thread_internal_init(void)
220 CtdlThreadNode *this_thread;
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");
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");
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));
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);
249 /* We are garbage collector so create us as running */
250 this_thread->state = CTDL_THREAD_RUNNING;
252 if ((ret = citthread_attr_init(&this_thread->attr))) {
253 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
258 this_thread->name = "Garbage Collection Thread";
260 this_thread->tid = GC_thread;
263 num_threads++; // Increase the count of threads in the system.
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. */
276 * A function to update a threads load averages
278 void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
280 struct timeval now, result;
281 double last_duration;
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);
300 * A function to chenge the state of a thread
302 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
305 * Wether we change state or not we need update the load values
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);
321 * A function to tell all threads to exit
323 void CtdlThreadStopAll(void)
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
328 CtdlThreadNode *this_thread;
330 begin_critical_section(S_THREAD_LIST);
331 this_thread = CtdlThreadList;
334 #ifdef THREADS_USESIGNALS
335 citthread_killl(this_thread->tid, SIGHUP);
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;
343 end_critical_section(S_THREAD_LIST);
348 * A function to wake up all sleeping threads
350 void CtdlThreadWakeAll(void)
352 CtdlThreadNode *this_thread;
354 CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
356 begin_critical_section(S_THREAD_LIST);
357 this_thread = CtdlThreadList;
360 if (!this_thread->thread_func)
362 citthread_cond_signal(&this_thread->ThreadCond);
363 citthread_cond_signal(&this_thread->SleepCond);
365 this_thread = this_thread->next;
367 end_critical_section(S_THREAD_LIST);
372 * A function to return the number of threads running in the system
374 int CtdlThreadGetCount(void)
379 int CtdlThreadGetWorkers(void)
384 double CtdlThreadGetWorkerAvg(void)
388 begin_critical_section(S_THREAD_LIST);
389 ret = CtdlThreadWorkerAvg;
390 end_critical_section(S_THREAD_LIST);
394 double CtdlThreadGetLoadAvg(void)
398 begin_critical_section(S_THREAD_LIST);
399 ret = CtdlThreadLoadAvg;
400 end_critical_section(S_THREAD_LIST);
408 * A function to rename a thread
409 * Returns a const char *
411 const char *CtdlThreadName(const char *name)
413 const char *old_name;
417 CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
428 * A function to force a thread to exit
430 void CtdlThreadCancel(CtdlThreadNode *thread)
432 CtdlThreadNode *this_thread;
437 this_thread = thread;
440 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
445 if (!this_thread->thread_func)
447 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
452 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
453 citthread_cancel(this_thread->tid);
458 * A function for a thread to check if it has been asked to stop
460 int CtdlThreadCheckStop(void)
466 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
473 #ifdef THREADS_USERSIGNALS
475 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
477 if(state == CTDL_THREAD_STOP_REQ)
479 CT->state = CTDL_THREAD_STOPPING;
482 else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
491 * A function to ask a thread to exit
492 * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
494 void CtdlThreadStop(CtdlThreadNode *thread)
496 CtdlThreadNode *this_thread;
501 this_thread = thread;
504 if (!(this_thread->thread_func))
505 return; // Don't stop garbage collector
506 #ifdef THREADS_USESIGNALS
507 citthread_kill(this_thread->tid, SIGHUP);
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);
515 * So we now have a sleep command that works with threads but it is in seconds
517 void CtdlThreadSleep(int secs)
519 struct timespec wake_time;
520 struct timeval time_now;
525 CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
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;
534 ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
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);
540 ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
545 * Routine to clean up our thread function on exit
547 static void ctdl_internal_thread_cleanup(void *arg)
550 * In here we were called by the current thread because it is exiting
551 * NB. WE ARE THE CURRENT THREAD
553 CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (%ld) exited.\n", CT->name, CT->tid);
555 #ifdef HAVE_BACKTRACE
556 eCrash_UnregisterThread();
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);
565 * A quick function to show the load averages
567 void ctdl_thread_internal_calc_loadavg(void)
569 CtdlThreadNode *that_thread;
570 double load_avg, worker_avg;
573 that_thread = CtdlThreadList;
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)
588 worker_avg += that_thread->load_avg;
591 #ifdef WITH_THREADLOG
592 CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
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);
601 citthread_mutex_unlock(&that_thread->ThreadMutex);
602 that_thread = that_thread->next;
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);
613 * Garbage collection routine.
614 * Gets called by main() in a loop to clean up the thread list periodically.
616 void CtdlThreadGC (void)
618 CtdlThreadNode *this_thread, *that_thread;
619 int workers = 0, sys_workers;
622 begin_critical_section(S_THREAD_LIST);
624 /* Handle exiting of garbage collector thread */
626 CtdlThreadList->state = CTDL_THREAD_EXITED;
628 #ifdef WITH_THREADLOG
629 CtdlLogPrintf(CTDL_DEBUG, "Thread system running garbage collection.\n");
632 * Woke up to do garbage collection
634 this_thread = CtdlThreadList;
637 that_thread = this_thread;
638 this_thread = this_thread->next;
640 /* Do we need to clean up this thread? */
641 if (that_thread->state != CTDL_THREAD_EXITED)
643 if(that_thread->flags & CTDLTHREAD_WORKER)
644 workers++; /* Sanity check on number of worker threads */
648 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
650 end_critical_section(S_THREAD_LIST);
651 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
656 if (num_threads <= 0)
658 end_critical_section(S_THREAD_LIST);
659 CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
664 if(that_thread->flags & CTDLTHREAD_WORKER)
665 num_workers--; /* This is a wroker thread so reduce the count. */
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;
671 CtdlThreadList = that_thread->next;
672 if(that_thread->next)
673 that_thread->next->prev = that_thread->prev;
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);
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
684 ret = citthread_join (that_thread->tid, NULL);
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");
692 CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, citthread_join returned an unknown error.\n");
694 * Now we own that thread entry
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);
704 sys_workers = num_workers;
705 end_critical_section(S_THREAD_LIST);
707 /* Sanity check number of worker threads */
708 if (workers != sys_workers)
710 CtdlLogPrintf(CTDL_EMERG,
711 "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
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.
726 static void *ctdl_internal_thread_func (void *arg)
728 CtdlThreadNode *this_thread;
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.
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);
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();
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.
751 citthread_mutex_unlock(&this_thread->ThreadMutex);
753 if (!CtdlThreadCheckStop())
755 citthread_mutex_lock(&this_thread->ThreadMutex);
756 this_thread->state = CTDL_THREAD_RUNNING;
757 citthread_mutex_unlock(&this_thread->ThreadMutex);
759 end_critical_section(S_THREAD_LIST);
761 // Register for tracing
762 #ifdef HAVE_BACKTRACE
763 eCrash_RegisterThread(this_thread->name, 0);
766 // Tell the world we are here
767 CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (%ld). \n", this_thread->name, this_thread->tid);
772 * run the thread to do the work but only if we haven't been asked to stop
774 if (!CtdlThreadCheckStop())
775 ret = (this_thread->thread_func)(this_thread->user_args);
778 * Our thread is exiting either because it wanted to end or because the server is stopping
779 * We need to clean up
781 citthread_cleanup_pop(1); // Execute our cleanup routine and remove it
789 * Internal function to create a thread.
790 * Must be called from within a S_THREAD_LIST critical section
792 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
795 CtdlThreadNode *this_thread;
797 if (num_threads >= 32767)
799 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
803 this_thread = malloc(sizeof(CtdlThreadNode));
804 if (this_thread == NULL) {
805 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
808 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
809 memset (this_thread, 0, sizeof(CtdlThreadNode));
811 /* Create the mutex's early so we can use them */
812 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
813 citthread_cond_init (&(this_thread->ThreadCond), NULL);
814 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
815 citthread_cond_init (&(this_thread->SleepCond), NULL);
817 citthread_mutex_lock(&this_thread->ThreadMutex);
819 this_thread->state = CTDL_THREAD_CREATE;
821 if ((ret = citthread_attr_init(&this_thread->attr))) {
822 citthread_mutex_unlock(&this_thread->ThreadMutex);
823 citthread_mutex_destroy(&(this_thread->ThreadMutex));
824 citthread_cond_destroy(&(this_thread->ThreadCond));
825 citthread_mutex_destroy(&(this_thread->SleepMutex));
826 citthread_cond_destroy(&(this_thread->SleepCond));
827 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
832 /* Our per-thread stacks need to be bigger than the default size,
833 * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
834 * crashes on 64-bit Linux.
836 if (flags & CTDLTHREAD_BIGSTACK)
838 #ifdef WITH_THREADLOG
839 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
841 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
842 citthread_mutex_unlock(&this_thread->ThreadMutex);
843 citthread_mutex_destroy(&(this_thread->ThreadMutex));
844 citthread_cond_destroy(&(this_thread->ThreadCond));
845 citthread_mutex_destroy(&(this_thread->SleepMutex));
846 citthread_cond_destroy(&(this_thread->SleepCond));
847 citthread_attr_destroy(&this_thread->attr);
848 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
856 * If we got here we are going to create the thread so we must initilise the structure
857 * first because most implimentations of threading can't create it in a stopped state
858 * and it might want to do things with its structure that aren't initialised otherwise.
862 this_thread->name = name;
866 this_thread->name = "Un-named Thread";
869 this_thread->flags = flags;
870 this_thread->thread_func = thread_func;
871 this_thread->user_args = args;
872 /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
873 * load average for the system. If we don't do this then we create a mass of threads at the same time
874 * because the creation didn't affect the load average.
876 this_thread->avg_blocked = 2;
879 * We pass this_thread into the thread as its args so that it can find out information
880 * about itself and it has a bit of storage space for itself, not to mention that the REAL
881 * thread function needs to finish off the setup of the structure
883 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
886 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
888 citthread_mutex_unlock(&this_thread->ThreadMutex);
889 citthread_mutex_destroy(&(this_thread->ThreadMutex));
890 citthread_cond_destroy(&(this_thread->ThreadCond));
891 citthread_mutex_destroy(&(this_thread->SleepMutex));
892 citthread_cond_destroy(&(this_thread->SleepCond));
893 citthread_attr_destroy(&this_thread->attr);
898 num_threads++; // Increase the count of threads in the system.
899 if(this_thread->flags & CTDLTHREAD_WORKER)
902 this_thread->next = CtdlThreadList;
903 CtdlThreadList = this_thread;
904 if (this_thread->next)
905 this_thread->next->prev = this_thread;
907 citthread_mutex_unlock(&this_thread->ThreadMutex);
909 ctdl_thread_internal_calc_loadavg();
914 * Wrapper function to create a thread
915 * ensures the critical section and other protections are in place.
916 * char *name = name to give to thread, if NULL, use generic name
917 * int flags = flags to determine type of thread and standard facilities
919 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
921 CtdlThreadNode *ret = NULL;
923 begin_critical_section(S_THREAD_LIST);
924 ret = ctdl_internal_create_thread(name, flags, thread_func, args);
925 end_critical_section(S_THREAD_LIST);
932 * Internal function to schedule a thread.
933 * Must be called from within a S_THREAD_LIST critical section
935 CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
938 CtdlThreadNode *this_thread;
940 if (num_threads >= 32767)
942 CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
946 this_thread = malloc(sizeof(CtdlThreadNode));
947 if (this_thread == NULL) {
948 CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
951 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
952 memset (this_thread, 0, sizeof(CtdlThreadNode));
954 /* Create the mutex's early so we can use them */
955 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
956 citthread_cond_init (&(this_thread->ThreadCond), NULL);
957 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
958 citthread_cond_init (&(this_thread->SleepCond), NULL);
960 this_thread->state = CTDL_THREAD_CREATE;
962 if ((ret = citthread_attr_init(&this_thread->attr))) {
963 citthread_mutex_destroy(&(this_thread->ThreadMutex));
964 citthread_cond_destroy(&(this_thread->ThreadCond));
965 citthread_mutex_destroy(&(this_thread->SleepMutex));
966 citthread_cond_destroy(&(this_thread->SleepCond));
967 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
972 /* Our per-thread stacks need to be bigger than the default size,
973 * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
974 * crashes on 64-bit Linux.
976 if (flags & CTDLTHREAD_BIGSTACK)
978 CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
979 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
980 citthread_mutex_destroy(&(this_thread->ThreadMutex));
981 citthread_cond_destroy(&(this_thread->ThreadCond));
982 citthread_mutex_destroy(&(this_thread->SleepMutex));
983 citthread_cond_destroy(&(this_thread->SleepCond));
984 citthread_attr_destroy(&this_thread->attr);
985 CtdlLogPrintf(CTDL_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
993 * If we got here we are going to create the thread so we must initilise the structure
994 * first because most implimentations of threading can't create it in a stopped state
995 * and it might want to do things with its structure that aren't initialised otherwise.
999 this_thread->name = name;
1003 this_thread->name = "Un-named Thread";
1006 this_thread->flags = flags;
1007 this_thread->thread_func = thread_func;
1008 this_thread->user_args = args;
1009 /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
1010 * load average for the system. If we don't do this then we create a mass of threads at the same time
1011 * because the creation didn't affect the load average.
1013 this_thread->avg_blocked = 2;
1016 * When to start this thread
1018 this_thread->when = when;
1020 begin_critical_section(S_SCHEDULE_LIST);
1021 this_thread->next = CtdlThreadSchedList;
1022 CtdlThreadSchedList = this_thread;
1023 if (this_thread->next)
1024 this_thread->next->prev = this_thread;
1025 end_critical_section(S_SCHEDULE_LIST);
1032 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1037 * We pass this_thread into the thread as its args so that it can find out information
1038 * about itself and it has a bit of storage space for itself, not to mention that the REAL
1039 * thread function needs to finish off the setup of the structure
1041 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1044 CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
1050 num_threads++; // Increase the count of threads in the system.
1051 if(this_thread->flags & CTDLTHREAD_WORKER)
1054 this_thread->next = CtdlThreadList;
1055 CtdlThreadList = this_thread;
1056 if (this_thread->next)
1057 this_thread->next->prev = this_thread;
1064 void ctdl_thread_internal_check_scheduled(void)
1066 CtdlThreadNode *this_thread, *that_thread;
1069 if (try_critical_section(S_SCHEDULE_LIST))
1070 return; /* If this list is locked we wait till the next chance */
1074 #ifdef WITH_THREADLOG
1075 CtdlLogPrintf(CTDL_DEBUG, "Checking for scheduled threads to start.\n");
1078 this_thread = CtdlThreadSchedList;
1081 that_thread = this_thread;
1082 this_thread = this_thread->next;
1084 if (now > that_thread->when)
1086 /* Unlink from schedule list */
1087 if (that_thread->prev)
1088 that_thread->prev->next = that_thread->next;
1090 CtdlThreadSchedList = that_thread->next;
1091 if (that_thread->next)
1092 that_thread->next->prev = that_thread->prev;
1094 that_thread->next = that_thread->prev = NULL;
1095 #ifdef WITH_THREADLOG
1096 CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1098 begin_critical_section(S_THREAD_LIST);
1099 if (CT->state > CTDL_THREAD_STOP_REQ)
1100 { /* Only start it if the system is not stopping */
1101 citthread_mutex_lock(&that_thread->ThreadMutex);
1102 if (ctdl_thread_internal_start_scheduled (that_thread) == NULL)
1104 #ifdef WITH_THREADLOG
1105 CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\".\n", that_thread->name);
1107 citthread_mutex_unlock(&that_thread->ThreadMutex);
1108 citthread_mutex_destroy(&(that_thread->ThreadMutex));
1109 citthread_cond_destroy(&(that_thread->ThreadCond));
1110 citthread_mutex_destroy(&(that_thread->SleepMutex));
1111 citthread_cond_destroy(&(that_thread->SleepCond));
1112 citthread_attr_destroy(&that_thread->attr);
1117 CtdlLogPrintf(CTDL_INFO, "Thread system, Started a scheduled thread \"%s\" (%ld).\n",
1118 that_thread->name, that_thread->tid);
1119 citthread_mutex_unlock(&that_thread->ThreadMutex);
1120 ctdl_thread_internal_calc_loadavg();
1123 end_critical_section(S_THREAD_LIST);
1127 #ifdef WITH_THREADLOG
1128 CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n", that_thread->name, that_thread->when - time(NULL));
1132 end_critical_section(S_SCHEDULE_LIST);
1137 * A warapper function for select so we can show a thread as blocked
1139 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1143 ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1144 ret = select(n, readfds, writefds, exceptfds, timeout);
1145 ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1151 void *new_worker_thread(void *arg);
1152 extern void close_masters (void);
1156 void go_threading(void)
1159 CtdlThreadNode *last_worker;
1162 * Initialise the thread system
1164 ctdl_thread_internal_init();
1166 /* Second call to module init functions now that threading is up */
1167 initialise_modules(1);
1170 * This thread is now used for garbage collection of other threads in the thread list
1172 CtdlLogPrintf(CTDL_INFO, "Startup thread %d becoming garbage collector,\n", citthread_self());
1175 * We do a lot of locking and unlocking of the thread list in here.
1176 * We do this so that we can repeatedly release time for other threads
1177 * that may be waiting on the thread list.
1178 * We are a low priority thread so we can afford to do this
1181 while (CtdlThreadGetCount())
1184 exit_signal = CT->signal;
1187 CtdlThreadStopAll();
1190 check_sched_shutdown();
1191 if (CT->state > CTDL_THREAD_STOP_REQ)
1193 begin_critical_section(S_THREAD_LIST);
1194 ctdl_thread_internal_calc_loadavg();
1195 end_critical_section(S_THREAD_LIST);
1197 ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1200 /* Reduce the size of the worker thread pool if necessary. */
1201 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1203 /* Ask a worker thread to stop as we no longer need it */
1204 begin_critical_section(S_THREAD_LIST);
1205 last_worker = CtdlThreadList;
1208 citthread_mutex_lock(&last_worker->ThreadMutex);
1209 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1211 citthread_mutex_unlock(&last_worker->ThreadMutex);
1214 citthread_mutex_unlock(&last_worker->ThreadMutex);
1215 last_worker = last_worker->next;
1217 end_critical_section(S_THREAD_LIST);
1220 #ifdef WITH_THREADLOG
1221 CtdlLogPrintf(CTDL_DEBUG, "Thread system, stopping excess worker thread \"%s\" (%ld).\n",
1226 CtdlThreadStop(last_worker);
1231 * If all our workers are working hard, start some more to help out
1234 /* FIXME: come up with a better way to dynamically alter the number of threads
1235 * based on the system load
1238 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkers() <= num_sessions) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1240 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60) && (CtdlThreadGetLoadAvg() < 90) ) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1241 #endif /* NEW_WORKER */
1243 for (i=0; i<5 ; i++)
1246 CtdlThreadCreate("Worker Thread",
1247 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1252 CtdlThreadCreate("Worker Thread",
1253 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1257 #endif /* NEW_WORKER */
1263 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1268 if (CtdlThreadGetCount())
1272 * If the above loop exits we must be shutting down since we obviously have no threads
1274 ctdl_thread_internal_cleanup();
1281 * Starting a new implimentation of a worker thread.
1282 * This new implimentation will be faster and do more work per thread.
1286 * Select on master socket.
1287 * First worker thread in here acquires the lock and builds an FDSET of master sockets.
1288 * then it goes into a loop selecting on the master sockets timing out every few milliseconds.
1289 * If it times out it rebiulds its list and loops.
1290 * If the select succeeds it creates a new context and returns.
1291 * During this time the other workers are selecting on existing contexts or sleeping.
1293 void select_on_master(void)
1296 struct ServiceFunctionHook *serviceptr;
1297 int ssock; /* Descriptor for client socket */
1302 struct CitContext *con;
1303 const char *old_name;
1307 old_name = CtdlThreadName("select_on_master");
1309 /* Initialize the fdset. */
1313 /* First, add the various master sockets to the fdset. */
1314 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1315 m = serviceptr->msock;
1316 FD_SET(m, &readfds);
1322 tv.tv_sec = 1; /* wake up every 1 sec if no input */
1324 retval = CtdlThreadSelect(highest + 1, &readfds, NULL, NULL, &tv);
1326 /* Select got an error or we are shutting down so get out */
1327 if (retval == 0 || CtdlThreadCheckStop()) {
1328 CtdlThreadName(old_name);
1332 /* Select says something happened on one of our master sockets so now we handle it */
1333 for (serviceptr = ServiceHookTable; serviceptr != NULL; serviceptr = serviceptr->next ) {
1334 if (FD_ISSET(serviceptr->msock, &readfds)) {
1335 ssock = accept(serviceptr->msock, NULL, 0);
1337 CtdlLogPrintf(CTDL_DEBUG, "New client socket %d\n", ssock);
1338 /* The master socket is non-blocking but the client
1339 * sockets need to be blocking, otherwise certain
1340 * operations barf on FreeBSD. Not a fatal error.
1342 if (fcntl(ssock, F_SETFL, 0) < 0) {
1343 CtdlLogPrintf(CTDL_EMERG,
1344 "citserver: Can't set socket to blocking: %s\n",
1348 /* New context will be created already
1349 * set up in the CON_EXECUTING state.
1351 con = CreateNewContext();
1354 /* Assign our new socket number to it. */
1355 con->client_socket = ssock;
1356 con->h_command_function = serviceptr->h_command_function;
1357 con->h_async_function = serviceptr->h_async_function;
1358 con->ServiceName = serviceptr->ServiceName;
1359 /* Determine whether it's a local socket */
1360 if (serviceptr->sockpath != NULL)
1361 con->is_local_socket = 1;
1363 /* Set the SO_REUSEADDR socket option */
1365 setsockopt(ssock, SOL_SOCKET, SO_REUSEADDR, &i, sizeof(i));
1367 become_session(con);
1369 serviceptr->h_greeting_function();
1370 become_session(NULL);
1371 con->state = CON_IDLE;
1377 CtdlThreadName(old_name);
1381 * Select on client socket.
1382 * First worker thread in here acquires the lock and builds an FDSET of client sockets.
1383 * then it selects on the client sockets timing out after 1 second.
1384 * If it times out the thread goes off to check on housekeeping etc.
1385 * If the select succeeds the thread goes off to handle the client request.
1386 * If the list of client connections is empty the threads all sleep for one second
1388 struct CitContext *select_on_client(void)
1394 const char *old_name;
1397 old_name = CtdlThreadName("select_on_client");
1399 /* Initialise the fdset */
1401 FD_SET(CT->Context->client_socket, &readfds);
1402 highest = CT->Context->client_socket;
1403 /* Now we can select on any connections that are waiting */
1405 if (!CtdlThreadCheckStop())
1407 tv.tv_sec = config.c_sleeping; /* wake up every second if no input */
1409 retval = select(highest + 1, &readfds, NULL, NULL, &tv);
1411 else /* Shutting down? */
1413 CtdlThreadName(old_name);
1418 /* Now figure out who made this select() unblock.
1419 * First, check for an error or exit condition.
1422 if (errno == EBADF) {
1423 CtdlLogPrintf(CTDL_NOTICE, "select() failed: (%s)\n",
1426 if (errno != EINTR) {
1427 CtdlLogPrintf(CTDL_EMERG, "Exiting (%s)\n", strerror(errno));
1428 CtdlThreadStopAll();
1429 } else if (!CtdlThreadCheckStop()) {
1430 CtdlLogPrintf(CTDL_DEBUG, "Un handled select failure.\n");
1432 CtdlThreadName(old_name);
1435 else if(retval == 0)
1437 CtdlThreadName(old_name);
1438 CT->Context->kill_me = 1;
1443 CT->Context->state = CON_EXECUTING;
1444 CT->Context->input_waiting = 1;
1446 CtdlThreadName(old_name);
1447 return (CT->Context);
1453 * Do the worker threads work when needed
1455 int execute_session(struct CitContext *bind_me)
1459 become_session(bind_me);
1461 /* If the client has sent a command, execute it. */
1462 if (CC->input_waiting) {
1463 CC->h_command_function();
1464 CC->input_waiting = 0;
1467 /* If there are asynchronous messages waiting and the
1468 * client supports it, do those now */
1469 if ((CC->is_async) && (CC->async_waiting)
1470 && (CC->h_async_function != NULL)) {
1471 CC->h_async_function();
1472 CC->async_waiting = 0;
1475 force_purge = CC->kill_me;
1478 become_session(NULL);
1479 bind_me->state = CON_IDLE;
1485 extern void dead_session_purge(int force);
1488 * A new worker_thread loop.
1491 void *new_worker_thread(void *arg)
1493 struct CitContext *bind_me;
1496 while (!CtdlThreadCheckStop()) {
1498 /* make doubly sure we're not holding any stale db handles
1499 * which might cause a deadlock.
1501 cdb_check_handles();
1503 bind_me = NULL; /* Which session shall we handle? */
1505 if (CT->Context == NULL)
1507 if (CtdlThreadCheckStop())
1511 bind_me = select_on_client();
1512 if (CtdlThreadCheckStop())
1516 force_purge = execute_session(bind_me);
1518 dead_session_purge(force_purge);
1519 if (CtdlThreadCheckStop())