2 * Thread handling stuff for Citadel server
4 * Copyright (c) 1987-2011 by the citadel.org team
6 * This program is open source software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include <sys/types.h>
26 #include <sys/socket.h>
33 #if TIME_WITH_SYS_TIME
34 # include <sys/time.h>
38 # include <sys/time.h>
47 # if HAVE_SYS_SYSCALL_H
48 # include <sys/syscall.h>
52 #include <libcitadel.h>
55 #include "ctdl_module.h"
56 #include "modules_init.h"
57 #include "housekeeping.h"
59 #include "citserver.h"
60 #include "sysdep_decls.h"
62 #include "event_client.h"
65 * define this to use the new worker_thread method of handling connections
70 * New thread interface.
71 * To create a thread you must call one of the create thread functions.
72 * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
73 * struct CtdlThreadNode *node = NULL;
75 * If the thread is created *node will point to the thread control structure for the created thread.
76 * If the thread creation fails *node remains NULL
77 * Do not free the memory pointed to by *node, it doesn't belong to you.
78 * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
79 * remove the need for the calls to eCrashRegisterThread and friends
82 static int num_threads = 0; /* Current number of threads */
83 static int num_workers = 0; /* Current number of worker threads */
84 long statcount = 0; /* are we doing a stats check? */
85 static long stats_done = 0;
87 CtdlThreadNode *CtdlThreadList = NULL;
88 CtdlThreadNode *CtdlThreadSchedList = NULL;
90 static CtdlThreadNode *GC_thread = NULL;
91 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
92 double CtdlThreadLoadAvg = 0;
93 double CtdlThreadWorkerAvg = 0;
94 citthread_key_t ThreadKey;
96 citthread_mutex_t Critters[MAX_SEMAPHORES]; /* Things needing locking */
100 void InitialiseSemaphores(void)
104 /* Set up a bunch of semaphores to be used for critical sections */
105 for (i=0; i<MAX_SEMAPHORES; ++i) {
106 citthread_mutex_init(&Critters[i], NULL);
114 * Obtain a semaphore lock to begin a critical section.
115 * but only if no one else has one
117 int try_critical_section(int which_one)
119 /* For all types of critical sections except those listed here,
120 * ensure nobody ever tries to do a critical section within a
121 * transaction; this could lead to deadlock.
123 if ( (which_one != S_FLOORCACHE)
124 #ifdef DEBUG_MEMORY_LEAKS
125 && (which_one != S_DEBUGMEMLEAKS)
127 && (which_one != S_RPLIST)
131 return (citthread_mutex_trylock(&Critters[which_one]));
136 * Obtain a semaphore lock to begin a critical section.
138 void begin_critical_section(int which_one)
140 /* syslog(LOG_DEBUG, "begin_critical_section(%d)\n", which_one); */
142 /* For all types of critical sections except those listed here,
143 * ensure nobody ever tries to do a critical section within a
144 * transaction; this could lead to deadlock.
146 if ( (which_one != S_FLOORCACHE)
147 #ifdef DEBUG_MEMORY_LEAKS
148 && (which_one != S_DEBUGMEMLEAKS)
150 && (which_one != S_RPLIST)
154 citthread_mutex_lock(&Critters[which_one]);
158 * Release a semaphore lock to end a critical section.
160 void end_critical_section(int which_one)
162 citthread_mutex_unlock(&Critters[which_one]);
167 * A function to destroy the TSD
169 static void ctdl_thread_internal_dest_tsd(void *arg)
179 * A function to initialise the thread TSD
181 void ctdl_thread_internal_init_tsd(void)
185 if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
186 syslog(LOG_EMERG, "citthread_key_create: %s\n", strerror(ret));
192 * Ensure that we have a key for thread-specific data.
194 * This should be called immediately after startup by any thread
197 void CtdlThreadAllocTSD(void)
201 if (citthread_getspecific(ThreadKey) != NULL)
204 tsd = malloc(sizeof(ThreadTSD));
208 memset(tsd->cursors, 0, sizeof tsd->cursors);
211 citthread_setspecific(ThreadKey, tsd);
215 void ctdl_thread_internal_free_tsd(void)
217 ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
218 citthread_setspecific(ThreadKey, NULL);
222 void ctdl_thread_internal_cleanup(void)
225 CtdlThreadNode *this_thread, *that_thread;
227 for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
229 free (CtdlThreadStates[i]);
232 /* Clean up the scheduled thread list */
233 this_thread = CtdlThreadSchedList;
236 that_thread = this_thread;
237 this_thread = this_thread->next;
238 citthread_mutex_destroy(&that_thread->ThreadMutex);
239 citthread_cond_destroy(&that_thread->ThreadCond);
240 citthread_mutex_destroy(&that_thread->SleepMutex);
241 citthread_cond_destroy(&that_thread->SleepCond);
242 citthread_attr_destroy(&that_thread->attr);
245 ctdl_thread_internal_free_tsd();
248 void ctdl_thread_internal_init(void)
250 CtdlThreadNode *this_thread;
253 CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
254 CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
255 CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
256 CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
257 CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
258 CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
259 CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
260 CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
261 CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
262 CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
264 /* Get ourself a thread entry */
265 this_thread = malloc(sizeof(CtdlThreadNode));
266 if (this_thread == NULL) {
267 syslog(LOG_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
270 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
271 memset (this_thread, 0, sizeof(CtdlThreadNode));
273 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
274 citthread_cond_init (&(this_thread->ThreadCond), NULL);
275 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
276 citthread_cond_init (&(this_thread->SleepCond), NULL);
278 /* We are garbage collector so create us as running */
279 this_thread->state = CTDL_THREAD_RUNNING;
281 if ((ret = citthread_attr_init(&this_thread->attr))) {
282 syslog(LOG_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
287 this_thread->name = "Garbage Collection Thread";
289 this_thread->tid = citthread_self();
290 GC_thread = this_thread;
293 num_threads++; // Increase the count of threads in the system.
295 this_thread->next = CtdlThreadList;
296 CtdlThreadList = this_thread;
297 if (this_thread->next)
298 this_thread->next->prev = this_thread;
299 /* Set up start times */
300 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
301 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
306 * A function to update a threads load averages
308 void ctdl_thread_internal_update_avgs(CtdlThreadNode *this_thread)
310 struct timeval now, result;
311 double last_duration;
313 gettimeofday(&now, NULL);
314 timersub(&now, &(this_thread->last_state_change), &result);
315 /* I don't think these mutex's are needed here */
316 citthread_mutex_lock(&this_thread->ThreadMutex);
317 // result now has a timeval for the time we spent in the last state since we last updated
318 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
319 if (this_thread->state == CTDL_THREAD_SLEEPING)
320 this_thread->avg_sleeping += last_duration;
321 if (this_thread->state == CTDL_THREAD_RUNNING)
322 this_thread->avg_running += last_duration;
323 if (this_thread->state == CTDL_THREAD_BLOCKED)
324 this_thread->avg_blocked += last_duration;
325 memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
326 citthread_mutex_unlock(&this_thread->ThreadMutex);
330 * A function to chenge the state of a thread
332 void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
335 * Wether we change state or not we need update the load values
337 ctdl_thread_internal_update_avgs(this_thread);
338 /* This mutex not needed here? */
339 citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
340 if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
341 this_thread->state = new_state;
342 if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
343 this_thread->state = new_state;
344 if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
345 this_thread->state = new_state;
346 citthread_mutex_unlock(&this_thread->ThreadMutex);
351 * A function to tell all threads to exit
353 void CtdlThreadStopAll(void)
355 /* First run any registered shutdown hooks. This probably doesn't belong here. */
356 PerformSessionHooks(EVT_SHUTDOWN);
358 /* then close all tcp ports so nobody else can talk to us anymore. */
359 CtdlShutdownServiceHooks();
360 //FIXME: The signalling of the condition should not be in the critical_section
361 // We need to build a list of threads we are going to signal and then signal them afterwards
363 ShutDownEventQueue();
365 CtdlThreadNode *this_thread;
367 begin_critical_section(S_THREAD_LIST);
368 this_thread = CtdlThreadList;
369 // Ask the GC thread to stop first so everything knows we are shutting down.
370 GC_thread->state = CTDL_THREAD_STOP_REQ;
373 if (!citthread_equal(this_thread->tid, GC_thread->tid))
374 citthread_kill(this_thread->tid, SIGHUP);
376 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
377 citthread_cond_signal(&this_thread->ThreadCond);
378 citthread_cond_signal(&this_thread->SleepCond);
379 this_thread->stop_ticker = time(NULL);
380 syslog(LOG_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
381 this_thread->name, this_thread->tid);
382 this_thread = this_thread->next;
384 end_critical_section(S_THREAD_LIST);
389 * A function to wake up all sleeping threads
391 void CtdlThreadWakeAll(void)
393 CtdlThreadNode *this_thread;
395 syslog(LOG_DEBUG, "Thread system waking all threads.\n");
397 begin_critical_section(S_THREAD_LIST);
398 this_thread = CtdlThreadList;
401 if (!this_thread->thread_func)
403 citthread_cond_signal(&this_thread->ThreadCond);
404 citthread_cond_signal(&this_thread->SleepCond);
406 this_thread = this_thread->next;
408 end_critical_section(S_THREAD_LIST);
413 * A function to return the number of threads running in the system
415 int CtdlThreadGetCount(void)
420 int CtdlThreadGetWorkers(void)
425 double CtdlThreadGetWorkerAvg(void)
429 begin_critical_section(S_THREAD_LIST);
430 ret = CtdlThreadWorkerAvg;
431 end_critical_section(S_THREAD_LIST);
435 double CtdlThreadGetLoadAvg(void)
437 double load_avg[3] = {0.0, 0.0, 0.0};
442 /* Borrowed this straight from procps */
443 smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
444 if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
446 #ifdef HAVE_GETLOADAVG
447 ret = getloadavg(load_avg, 3);
451 return load_avg[0] / smp_num_cpus;
453 * This old chunk of code return a value that indicated the load on citserver
454 * This value could easily reach 100 % even when citserver was doing very little and
455 * hence the machine has much more spare capacity.
456 * Because this value was used to determine if the machine was under heavy load conditions
457 * from other processes in the system then citserver could be strangled un-necesarily
458 * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
459 * So we have changed this.
461 begin_critical_section(S_THREAD_LIST);
462 ret = CtdlThreadLoadAvg;
463 end_critical_section(S_THREAD_LIST);
472 * A function to rename a thread
473 * Returns a const char *
475 const char *CtdlThreadName(const char *name)
477 const char *old_name;
481 syslog(LOG_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
492 * A function to force a thread to exit
494 void CtdlThreadCancel(CtdlThreadNode *thread)
496 CtdlThreadNode *this_thread;
501 this_thread = thread;
504 syslog(LOG_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
509 if (!this_thread->thread_func)
511 syslog(LOG_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
516 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
517 citthread_cancel(this_thread->tid);
522 * A function for a thread to check if it has been asked to stop
524 int CtdlThreadCheckStop(void)
530 syslog(LOG_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
539 syslog(LOG_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
540 if (CT->signal == SIGHUP)
541 CT->state = CTDL_THREAD_STOP_REQ;
544 if(state == CTDL_THREAD_STOP_REQ)
546 CT->state = CTDL_THREAD_STOPPING;
549 else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
558 * A function to ask a thread to exit
559 * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
561 void CtdlThreadStop(CtdlThreadNode *thread)
563 CtdlThreadNode *this_thread;
568 this_thread = thread;
571 if (!(this_thread->thread_func))
572 return; // Don't stop garbage collector
574 if (!citthread_equal(this_thread->tid, GC_thread->tid))
575 citthread_kill(this_thread->tid, SIGHUP);
577 ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
578 citthread_cond_signal(&this_thread->ThreadCond);
579 citthread_cond_signal(&this_thread->SleepCond);
580 this_thread->stop_ticker = time(NULL);
584 * So we now have a sleep command that works with threads but it is in seconds
586 void CtdlThreadSleep(int secs)
588 struct timespec wake_time;
589 struct timeval time_now;
594 syslog(LOG_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
598 memset (&wake_time, 0, sizeof(struct timespec));
599 gettimeofday(&time_now, NULL);
600 wake_time.tv_sec = time_now.tv_sec + secs;
601 wake_time.tv_nsec = time_now.tv_usec * 10;
603 ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
605 citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
606 citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
607 citthread_mutex_unlock(&CT->ThreadMutex);
609 ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
614 * Routine to clean up our thread function on exit
616 static void ctdl_internal_thread_cleanup(void *arg)
619 * In here we were called by the current thread because it is exiting
620 * NB. WE ARE THE CURRENT THREAD
624 const char *name = CT->name;
625 const pid_t tid = CT->tid;
627 syslog(LOG_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", name, (unsigned long) tid);
631 syslog(LOG_NOTICE, "some ((unknown ? ? ?) Thread exited.\n");
634 #ifdef HAVE_BACKTRACE
635 /// eCrash_UnregisterThread();
638 citthread_mutex_lock(&CT->ThreadMutex);
639 CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
640 citthread_mutex_unlock(&CT->ThreadMutex);
644 * A quick function to show the load averages
646 void ctdl_thread_internal_calc_loadavg(void)
648 CtdlThreadNode *that_thread;
649 double load_avg, worker_avg;
652 that_thread = CtdlThreadList;
657 /* Update load averages */
658 ctdl_thread_internal_update_avgs(that_thread);
659 citthread_mutex_lock(&that_thread->ThreadMutex);
660 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;
661 that_thread->avg_sleeping /= 2;
662 that_thread->avg_running /= 2;
663 that_thread->avg_blocked /= 2;
664 load_avg += that_thread->load_avg;
665 if (that_thread->flags & CTDLTHREAD_WORKER)
667 worker_avg += that_thread->load_avg;
670 #ifdef WITH_THREADLOG
671 syslog(LOG_DEBUG, "CtdlThread, \"%s\" (%lu) \"%s\" %.2f %.2f %.2f %.2f\n",
674 CtdlThreadStates[that_thread->state],
675 that_thread->avg_sleeping,
676 that_thread->avg_running,
677 that_thread->avg_blocked,
678 that_thread->load_avg);
680 citthread_mutex_unlock(&that_thread->ThreadMutex);
681 that_thread = that_thread->next;
683 CtdlThreadLoadAvg = load_avg/num_threads;
684 CtdlThreadWorkerAvg = worker_avg/workers;
685 #ifdef WITH_THREADLOG
686 syslog(LOG_INFO, "System load average %.2f, workers averag %.2f, threads %d, workers %d, sessions %d\n", CtdlThreadGetLoadAvg(), CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
692 * Garbage collection routine.
693 * Gets called by main() in a loop to clean up the thread list periodically.
695 void CtdlThreadGC (void)
697 CtdlThreadNode *this_thread, *that_thread;
698 int workers = 0, sys_workers;
701 begin_critical_section(S_THREAD_LIST);
703 /* Handle exiting of garbage collector thread */
705 CtdlThreadList->state = CTDL_THREAD_EXITED;
707 #ifdef WITH_THREADLOG
708 syslog(LOG_DEBUG, "Thread system running garbage collection.\n");
711 * Woke up to do garbage collection
713 this_thread = CtdlThreadList;
716 that_thread = this_thread;
717 this_thread = this_thread->next;
719 if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
720 && (!citthread_equal(that_thread->tid, citthread_self())))
722 syslog(LOG_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
723 terminate_stuck_sessions();
728 * Catch the situation where a worker was asked to stop but couldn't and we are not
731 that_thread->stop_ticker = 0;
734 if (that_thread->stop_ticker + 5 == time(NULL))
736 syslog(LOG_DEBUG, "Thread System: The thread \"%s\" (0x%08lx) failed to self terminate within 5 ticks. It would be cancelled now.\n", that_thread->name, that_thread->tid);
737 if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
738 syslog(LOG_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
739 // that_thread->state = CTDL_THREAD_CANCELLED;
740 that_thread->stop_ticker++;
741 // citthread_cancel(that_thread->tid);
745 /* Do we need to clean up this thread? */
746 if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
748 if(that_thread->flags & CTDLTHREAD_WORKER)
749 workers++; /* Sanity check on number of worker threads */
753 if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
755 end_critical_section(S_THREAD_LIST);
756 syslog(LOG_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
761 if (num_threads <= 0)
763 end_critical_section(S_THREAD_LIST);
764 syslog(LOG_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
769 if(that_thread->flags & CTDLTHREAD_WORKER)
770 num_workers--; /* This is a wroker thread so reduce the count. */
772 /* If we are unlinking the list head then the next becomes the list head */
773 if(that_thread->prev)
774 that_thread->prev->next = that_thread->next;
776 CtdlThreadList = that_thread->next;
777 if(that_thread->next)
778 that_thread->next->prev = that_thread->prev;
780 citthread_cond_signal(&that_thread->ThreadCond);
781 citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
782 citthread_mutex_lock(&that_thread->ThreadMutex); // Make sure it has done what its doing
783 citthread_mutex_unlock(&that_thread->ThreadMutex);
785 * Join on the thread to do clean up and prevent memory leaks
786 * Also makes sure the thread has cleaned up after itself before we remove it from the list
787 * We can join on the garbage collector thread the join should just return EDEADLCK
789 ret = citthread_join (that_thread->tid, NULL);
791 syslog(LOG_DEBUG, "Garbage collection on own thread.\n");
792 else if (ret == EINVAL)
793 syslog(LOG_DEBUG, "Garbage collection, that thread already joined on.\n");
794 else if (ret == ESRCH)
795 syslog(LOG_DEBUG, "Garbage collection, no thread to join on.\n");
797 syslog(LOG_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
799 * Now we own that thread entry
801 syslog(LOG_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
802 that_thread->name, that_thread->tid);
803 citthread_mutex_destroy(&that_thread->ThreadMutex);
804 citthread_cond_destroy(&that_thread->ThreadCond);
805 citthread_mutex_destroy(&that_thread->SleepMutex);
806 citthread_cond_destroy(&that_thread->SleepCond);
807 citthread_attr_destroy(&that_thread->attr);
810 sys_workers = num_workers;
811 end_critical_section(S_THREAD_LIST);
813 /* Sanity check number of worker threads */
814 if (workers != sys_workers)
817 "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
828 * Runtime function for a Citadel Thread.
829 * This initialises the threads environment and then calls the user supplied thread function
830 * Note that this is the REAL thread function and wraps the users thread function.
832 static void *ctdl_internal_thread_func (void *arg)
834 CtdlThreadNode *this_thread;
837 /* lock and unlock the thread list.
838 * This causes this thread to wait until all its creation stuff has finished before it
839 * can continue its execution.
841 begin_critical_section(S_THREAD_LIST);
842 this_thread = (CtdlThreadNode *) arg;
843 gettimeofday(&this_thread->start_time, NULL); /* Time this thread started */
845 // Register the cleanup function to take care of when we exit.
846 citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
847 // Get our thread data structure
848 CtdlThreadAllocTSD();
850 this_thread->pid = getpid();
851 memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval)); /* Changed state so mark it. */
852 /* Only change to running state if we weren't asked to stop during the create cycle
853 * Other wise there is a window to allow this threads creation to continue to full grown and
854 * therby prevent a shutdown of the server.
856 if (!CtdlThreadCheckStop())
858 citthread_mutex_lock(&this_thread->ThreadMutex);
859 this_thread->state = CTDL_THREAD_RUNNING;
860 citthread_mutex_unlock(&this_thread->ThreadMutex);
862 end_critical_section(S_THREAD_LIST);
864 // Register for tracing
865 #ifdef HAVE_BACKTRACE
866 /// eCrash_RegisterThread(this_thread->name, 0);
869 // Tell the world we are here
870 #if defined(HAVE_SYSCALL_H) && defined (SYS_gettid)
871 this_thread->reltid = syscall(SYS_gettid);
873 syslog(LOG_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
874 this_thread->name, this_thread->tid);
877 * run the thread to do the work but only if we haven't been asked to stop
879 if (!CtdlThreadCheckStop())
880 ret = (this_thread->thread_func)(this_thread->user_args);
883 * Our thread is exiting either because it wanted to end or because the server is stopping
884 * We need to clean up
886 citthread_cleanup_pop(1); // Execute our cleanup routine and remove it
895 * Function to initialise an empty thread structure
897 CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
901 // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
902 memset (this_thread, 0, sizeof(CtdlThreadNode));
904 /* Create the mutex's early so we can use them */
905 citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
906 citthread_cond_init (&(this_thread->ThreadCond), NULL);
907 citthread_mutex_init (&(this_thread->SleepMutex), NULL);
908 citthread_cond_init (&(this_thread->SleepCond), NULL);
910 this_thread->state = CTDL_THREAD_CREATE;
912 if ((ret = citthread_attr_init(&this_thread->attr))) {
913 citthread_mutex_unlock(&this_thread->ThreadMutex);
914 citthread_mutex_destroy(&(this_thread->ThreadMutex));
915 citthread_cond_destroy(&(this_thread->ThreadCond));
916 citthread_mutex_destroy(&(this_thread->SleepMutex));
917 citthread_cond_destroy(&(this_thread->SleepCond));
918 syslog(LOG_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
923 /* Our per-thread stacks need to be bigger than the default size,
924 * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
925 * crashes on 64-bit Linux.
927 if (flags & CTDLTHREAD_BIGSTACK)
929 #ifdef WITH_THREADLOG
930 syslog(LOG_INFO, "Thread system. Creating BIG STACK thread.\n");
932 if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
933 citthread_mutex_unlock(&this_thread->ThreadMutex);
934 citthread_mutex_destroy(&(this_thread->ThreadMutex));
935 citthread_cond_destroy(&(this_thread->ThreadCond));
936 citthread_mutex_destroy(&(this_thread->SleepMutex));
937 citthread_cond_destroy(&(this_thread->SleepCond));
938 citthread_attr_destroy(&this_thread->attr);
939 syslog(LOG_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
946 /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
947 * load average for the system. If we don't do this then we create a mass of threads at the same time
948 * because the creation didn't affect the load average.
950 this_thread->avg_blocked = 2;
952 return (this_thread);
959 * Internal function to create a thread.
961 CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
964 CtdlThreadNode *this_thread;
966 if (num_threads >= 32767)
968 syslog(LOG_EMERG, "Thread system. Thread list full.\n");
972 this_thread = malloc(sizeof(CtdlThreadNode));
973 if (this_thread == NULL) {
974 syslog(LOG_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
978 /* Initialise the thread structure */
979 if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
982 syslog(LOG_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
986 * If we got here we are going to create the thread so we must initilise the structure
987 * first because most implimentations of threading can't create it in a stopped state
988 * and it might want to do things with its structure that aren't initialised otherwise.
992 this_thread->name = name;
996 this_thread->name = "Un-named Thread";
999 this_thread->flags = flags;
1000 this_thread->thread_func = thread_func;
1001 this_thread->user_args = args;
1003 begin_critical_section(S_THREAD_LIST);
1005 * We pass this_thread into the thread as its args so that it can find out information
1006 * about itself and it has a bit of storage space for itself, not to mention that the REAL
1007 * thread function needs to finish off the setup of the structure
1009 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1011 end_critical_section(S_THREAD_LIST);
1012 syslog(LOG_ALERT, "Thread system, Can't create thread: %s\n",
1014 citthread_mutex_unlock(&this_thread->ThreadMutex);
1015 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1016 citthread_cond_destroy(&(this_thread->ThreadCond));
1017 citthread_mutex_destroy(&(this_thread->SleepMutex));
1018 citthread_cond_destroy(&(this_thread->SleepCond));
1019 citthread_attr_destroy(&this_thread->attr);
1023 num_threads++; // Increase the count of threads in the system.
1024 if(this_thread->flags & CTDLTHREAD_WORKER)
1027 this_thread->next = CtdlThreadList;
1028 CtdlThreadList = this_thread;
1029 if (this_thread->next)
1030 this_thread->next->prev = this_thread;
1031 ctdl_thread_internal_calc_loadavg();
1033 end_critical_section(S_THREAD_LIST);
1039 * Wrapper function to create a thread
1040 * ensures the critical section and other protections are in place.
1041 * char *name = name to give to thread, if NULL, use generic name
1042 * int flags = flags to determine type of thread and standard facilities
1044 CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
1046 CtdlThreadNode *ret = NULL;
1048 ret = ctdl_internal_create_thread(name, flags, thread_func, args);
1054 CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
1058 begin_critical_section(S_THREAD_LIST);
1060 * We pass this_thread into the thread as its args so that it can find out information
1061 * about itself and it has a bit of storage space for itself, not to mention that the REAL
1062 * thread function needs to finish off the setup of the structure
1064 if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
1066 end_critical_section(S_THREAD_LIST);
1067 syslog(LOG_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
1068 citthread_mutex_destroy(&(this_thread->ThreadMutex));
1069 citthread_cond_destroy(&(this_thread->ThreadCond));
1070 citthread_mutex_destroy(&(this_thread->SleepMutex));
1071 citthread_cond_destroy(&(this_thread->SleepCond));
1072 citthread_attr_destroy(&this_thread->attr);
1078 num_threads++; // Increase the count of threads in the system.
1079 if(this_thread->flags & CTDLTHREAD_WORKER)
1082 this_thread->next = CtdlThreadList;
1083 CtdlThreadList = this_thread;
1084 if (this_thread->next)
1085 this_thread->next->prev = this_thread;
1087 ctdl_thread_internal_calc_loadavg();
1088 end_critical_section(S_THREAD_LIST);
1096 void ctdl_thread_internal_check_scheduled(void)
1098 CtdlThreadNode *this_thread, *that_thread;
1101 /* Don't start scheduled threads if the system wants single user mode */
1102 if (CtdlWantSingleUser())
1105 if (try_critical_section(S_SCHEDULE_LIST))
1106 return; /* If this list is locked we wait till the next chance */
1110 #ifdef WITH_THREADLOG
1111 syslog(LOG_DEBUG, "Checking for scheduled threads to start.\n");
1114 this_thread = CtdlThreadSchedList;
1117 that_thread = this_thread;
1118 this_thread = this_thread->next;
1120 if (now > that_thread->when)
1122 /* Unlink from schedule list */
1123 if (that_thread->prev)
1124 that_thread->prev->next = that_thread->next;
1126 CtdlThreadSchedList = that_thread->next;
1127 if (that_thread->next)
1128 that_thread->next->prev = that_thread->prev;
1130 that_thread->next = that_thread->prev = NULL;
1131 #ifdef WITH_THREADLOG
1132 syslog(LOG_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
1134 if (CT->state > CTDL_THREAD_STOP_REQ)
1135 { /* Only start it if the system is not stopping */
1136 if (ctdl_thread_internal_start_scheduled (that_thread))
1138 #ifdef WITH_THREADLOG
1139 syslog(LOG_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
1140 that_thread->name, that_thread->tid);
1145 #ifdef WITH_THREADLOG
1148 syslog(LOG_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
1149 that_thread->name, that_thread->when - time(NULL));
1153 end_critical_section(S_SCHEDULE_LIST);
1158 * A warapper function for select so we can show a thread as blocked
1160 int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
1164 ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
1165 if (!CtdlThreadCheckStop())
1166 ret = select(n, readfds, writefds, exceptfds, timeout);
1168 * If the select returned <= 0 then it failed due to an error
1169 * or timeout so this thread could stop if asked to do so.
1170 * Anything else means it needs to continue unless the system is shutting down
1175 * The select says this thread needs to do something useful.
1176 * This thread was in an idle state so it may have been asked to stop
1177 * but if the system isn't shutting down this thread is no longer
1178 * idle and select has given it a task to do so it must not stop
1179 * In this condition we need to force it into the running state.
1180 * CtdlThreadGC will clear its ticker for us.
1182 * FIXME: there is still a small hole here. It is possible for the sequence of locking
1183 * to allow the state to get changed to STOP_REQ just after this code if the other thread
1184 * has decided to change the state before this lock, it there fore has to wait till the lock
1185 * completes but it will continue to change the state. We need something a bit better here.
1187 citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
1188 if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
1190 syslog(LOG_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
1191 CT->state = CTDL_THREAD_RUNNING;
1193 citthread_mutex_unlock(&CT->ThreadMutex);
1196 ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
1203 void *new_worker_thread(void *arg);
1204 extern void close_masters (void);
1207 void *simulation_worker (void*arg) {
1208 struct CitContext *this;
1210 this = CreateNewContext();
1213 this->state = CON_IDLE;
1214 dead_session_purge(1);
1215 begin_critical_section(S_SESSION_TABLE);
1217 end_critical_section(S_SESSION_TABLE);
1222 void *simulation_thread (void *arg)
1224 long stats = statcount;
1226 while(stats && !CtdlThreadCheckStop()) {
1227 CtdlThreadCreate("Connection simulation worker", CTDLTHREAD_BIGSTACK, simulation_worker, NULL);
1230 CtdlThreadStopAll();
1234 void go_threading(void)
1237 CtdlThreadNode *last_worker;
1238 struct timeval start, now, result;
1239 double last_duration;
1242 * Initialise the thread system
1244 ctdl_thread_internal_init();
1246 /* Second call to module init functions now that threading is up */
1248 initialise_modules(1);
1249 CtdlThreadCreate("select_on_master", CTDLTHREAD_BIGSTACK, select_on_master, NULL);
1252 syslog(LOG_EMERG, "Running connection simulation stats\n");
1253 gettimeofday(&start, NULL);
1254 CtdlThreadCreate("Connection simulation master", CTDLTHREAD_BIGSTACK, simulation_thread, NULL);
1259 * This thread is now used for garbage collection of other threads in the thread list
1261 syslog(LOG_INFO, "Startup thread %ld becoming garbage collector,\n", (long) citthread_self());
1264 * We do a lot of locking and unlocking of the thread list in here.
1265 * We do this so that we can repeatedly release time for other threads
1266 * that may be waiting on the thread list.
1267 * We are a low priority thread so we can afford to do this
1270 while (CtdlThreadGetCount())
1273 exit_signal = CT->signal;
1276 CtdlThreadStopAll();
1278 check_sched_shutdown();
1279 if (CT->state > CTDL_THREAD_STOP_REQ)
1281 begin_critical_section(S_THREAD_LIST);
1282 ctdl_thread_internal_calc_loadavg();
1283 end_critical_section(S_THREAD_LIST);
1285 ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
1288 /* Reduce the size of the worker thread pool if necessary. */
1289 if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
1291 /* Ask a worker thread to stop as we no longer need it */
1292 begin_critical_section(S_THREAD_LIST);
1293 last_worker = CtdlThreadList;
1296 citthread_mutex_lock(&last_worker->ThreadMutex);
1297 if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
1299 citthread_mutex_unlock(&last_worker->ThreadMutex);
1302 citthread_mutex_unlock(&last_worker->ThreadMutex);
1303 last_worker = last_worker->next;
1305 end_critical_section(S_THREAD_LIST);
1308 #ifdef WITH_THREADLOG
1309 syslog(LOG_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
1314 CtdlThreadStop(last_worker);
1319 * If all our workers are working hard, start some more to help out
1322 /* FIXME: come up with a better way to dynamically alter the number of threads
1323 * based on the system load
1326 if ((((CtdlThreadGetWorkers() < config.c_max_workers) && (CtdlThreadGetWorkerAvg() > 60)) || CtdlThreadGetWorkers() < config.c_min_workers) && (CT->state > CTDL_THREAD_STOP_REQ))
1328 /* Only start new threads if we are not going to overload the machine */
1329 /* Temporarily set to 10 should be enough to make sure we don't stranglew the server
1330 * at least until we make this a config option */
1331 if (CtdlThreadGetLoadAvg() < ((double)10.00)) {
1332 for (i=0; i<5 ; i++) {
1333 CtdlThreadCreate("Worker Thread",
1334 CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
1341 syslog(LOG_WARNING, "Server strangled due to machine load average too high.\n");
1347 if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
1352 #ifdef THREADS_USESIGNALS
1353 if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
1355 if (CtdlThreadGetCount())
1360 * If the above loop exits we must be shutting down since we obviously have no threads
1362 ctdl_thread_internal_cleanup();
1365 gettimeofday(&now, NULL);
1366 timersub(&now, &start, &result);
1367 last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
1368 syslog(LOG_EMERG, "Simulated %ld connections in %f seconds\n", stats_done, last_duration);