Switched back to the old style thread architecture in preparation for eventual migrat...
[citadel.git] / citadel / threads.c
index 1f066a0cd6e79e88f390db5bad0cec7f5d97e500..cb216febefa00d24a3339a419c103a46564dd358 100644 (file)
@@ -15,7 +15,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
 #include <stdlib.h>
  */
 
 static int num_threads = 0;                    /* Current number of threads */
-static int num_workers = 0;                    /* Current number of worker threads */
+pthread_key_t ThreadKey;
+pthread_mutex_t Critters[MAX_SEMAPHORES];      /* Things needing locking */
+struct thread_tsd masterTSD;
 
-CtdlThreadNode *CtdlThreadList = NULL;
-CtdlThreadNode *CtdlThreadSchedList = NULL;
 
-static CtdlThreadNode *GC_thread = NULL;
-static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
-double CtdlThreadLoadAvg = 0;
-double CtdlThreadWorkerAvg = 0;
-citthread_key_t ThreadKey;
 
-citthread_mutex_t Critters[MAX_SEMAPHORES];    /* Things needing locking */
-
-
-
-void InitialiseSemaphores(void)
+void InitializeSemaphores(void)
 {
        int i;
 
        /* Set up a bunch of semaphores to be used for critical sections */
        for (i=0; i<MAX_SEMAPHORES; ++i) {
-               citthread_mutex_init(&Critters[i], NULL);
+               pthread_mutex_init(&Critters[i], NULL);
        }
 }
 
@@ -118,7 +109,7 @@ int try_critical_section(int which_one)
        ) {
                cdb_check_handles();
        }
-       return (citthread_mutex_trylock(&Critters[which_one]));
+       return (pthread_mutex_trylock(&Critters[which_one]));
 }
 
 
@@ -127,8 +118,6 @@ int try_critical_section(int which_one)
  */
 void begin_critical_section(int which_one)
 {
-       /* syslog(LOG_DEBUG, "begin_critical_section(%d)\n", which_one); */
-
        /* For all types of critical sections except those listed here,
         * ensure nobody ever tries to do a critical section within a
         * transaction; this could lead to deadlock.
@@ -138,7 +127,7 @@ void begin_critical_section(int which_one)
        ) {
                cdb_check_handles();
        }
-       citthread_mutex_lock(&Critters[which_one]);
+       pthread_mutex_lock(&Critters[which_one]);
 }
 
 /*
@@ -146,166 +135,7 @@ void begin_critical_section(int which_one)
  */
 void end_critical_section(int which_one)
 {
-       citthread_mutex_unlock(&Critters[which_one]);
-}
-
-
-/*
- * A function to destroy the TSD
- */
-static void ctdl_thread_internal_dest_tsd(void *arg)
-{
-       if (arg != NULL) {
-               check_handles(arg);
-               free(arg);
-       }
-}
-
-
-/*
- * A function to initialise the thread TSD
- */
-void ctdl_thread_internal_init_tsd(void)
-{
-       int ret;
-       
-       if ((ret = citthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
-               syslog(LOG_EMERG, "citthread_key_create: %s\n", strerror(ret));
-               exit(CTDLEXIT_DB);
-       }
-}
-
-/*
- * Ensure that we have a key for thread-specific data. 
- *
- * This should be called immediately after startup by any thread 
- * 
- */
-void CtdlThreadAllocTSD(void)
-{
-       ThreadTSD *tsd;
-
-       if (citthread_getspecific(ThreadKey) != NULL)
-               return;
-
-       tsd = malloc(sizeof(ThreadTSD));
-
-       tsd->tid = NULL;
-
-       memset(tsd->cursors, 0, sizeof tsd->cursors);
-       tsd->self = NULL;
-       
-       citthread_setspecific(ThreadKey, tsd);
-}
-
-
-void ctdl_thread_internal_free_tsd(void)
-{
-       ctdl_thread_internal_dest_tsd(citthread_getspecific(ThreadKey));
-       citthread_setspecific(ThreadKey, NULL);
-}
-
-
-void ctdl_thread_internal_cleanup(void)
-{
-       int i;
-       CtdlThreadNode *this_thread, *that_thread;
-       
-       for (i=0; i<CTDL_THREAD_LAST_STATE; i++)
-       {
-               free (CtdlThreadStates[i]);
-       }
-       
-       /* Clean up the scheduled thread list */
-       this_thread = CtdlThreadSchedList;
-       while (this_thread)
-       {
-               that_thread = this_thread;
-               this_thread = this_thread->next;
-               citthread_mutex_destroy(&that_thread->ThreadMutex);
-               citthread_cond_destroy(&that_thread->ThreadCond);
-               citthread_mutex_destroy(&that_thread->SleepMutex);
-               citthread_cond_destroy(&that_thread->SleepCond);
-               citthread_attr_destroy(&that_thread->attr);
-               free(that_thread);
-       }
-       ctdl_thread_internal_free_tsd();
-}
-
-void ctdl_thread_internal_init(void)
-{
-       CtdlThreadNode *this_thread;
-       int ret = 0;
-       
-       CtdlThreadStates[CTDL_THREAD_INVALID] = strdup ("Invalid Thread");
-       CtdlThreadStates[CTDL_THREAD_VALID] = strdup("Valid Thread");
-       CtdlThreadStates[CTDL_THREAD_CREATE] = strdup("Thread being Created");
-       CtdlThreadStates[CTDL_THREAD_CANCELLED] = strdup("Thread Cancelled");
-       CtdlThreadStates[CTDL_THREAD_EXITED] = strdup("Thread Exited");
-       CtdlThreadStates[CTDL_THREAD_STOPPING] = strdup("Thread Stopping");
-       CtdlThreadStates[CTDL_THREAD_STOP_REQ] = strdup("Thread Stop Requested");
-       CtdlThreadStates[CTDL_THREAD_SLEEPING] = strdup("Thread Sleeping");
-       CtdlThreadStates[CTDL_THREAD_RUNNING] = strdup("Thread Running");
-       CtdlThreadStates[CTDL_THREAD_BLOCKED] = strdup("Thread Blocked");
-       
-       /* Get ourself a thread entry */
-       this_thread = malloc(sizeof(CtdlThreadNode));
-       if (this_thread == NULL) {
-               syslog(LOG_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
-               return;
-       }
-       // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
-       memset (this_thread, 0, sizeof(CtdlThreadNode));
-       
-       citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
-       citthread_cond_init (&(this_thread->ThreadCond), NULL);
-       citthread_mutex_init (&(this_thread->SleepMutex), NULL);
-       citthread_cond_init (&(this_thread->SleepCond), NULL);
-       
-       /* We are garbage collector so create us as running */
-       this_thread->state = CTDL_THREAD_RUNNING;
-       
-       if ((ret = citthread_attr_init(&this_thread->attr))) {
-               syslog(LOG_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
-               free(this_thread);
-               return;
-       }
-
-       this_thread->name = "Garbage Collection Thread";
-       
-       this_thread->tid = citthread_self();
-       GC_thread = this_thread;
-       CT = this_thread;
-       
-       num_threads++;  // Increase the count of threads in the system.
-
-       this_thread->next = CtdlThreadList;
-       CtdlThreadList = this_thread;
-       if (this_thread->next)
-               this_thread->next->prev = this_thread;
-       /* Set up start times */
-       gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
-       memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
-}
-
-
-/*
- * A function to chenge the state of a thread
- */
-void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
-{
-       /*
-        * Wether we change state or not we need update the load values
-        */
-       /* This mutex not needed here? */
-       citthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
-       if ((new_state == CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_STOP_REQ))
-               this_thread->state = new_state;
-       if (((new_state == CTDL_THREAD_SLEEPING) || (new_state == CTDL_THREAD_BLOCKED)) && (this_thread->state == CTDL_THREAD_RUNNING))
-               this_thread->state = new_state;
-       if ((new_state == CTDL_THREAD_RUNNING) && ((this_thread->state == CTDL_THREAD_SLEEPING) || (this_thread->state == CTDL_THREAD_BLOCKED)))
-               this_thread->state = new_state;
-       citthread_mutex_unlock(&this_thread->ThreadMutex);
+       pthread_mutex_unlock(&Critters[which_one]);
 }
 
 
@@ -314,169 +144,9 @@ void ctdl_thread_internal_change_state (CtdlThreadNode *this_thread, enum CtdlTh
  */
 void CtdlThreadStopAll(void)
 {
-       /* First run any registered shutdown hooks.  This probably doesn't belong here. */
-       PerformSessionHooks(EVT_SHUTDOWN);
-       
-       /* then close all tcp ports so nobody else can talk to us anymore. */
-       CtdlShutdownServiceHooks();
-       //FIXME: The signalling of the condition should not be in the critical_section
-       // We need to build a list of threads we are going to signal and then signal them afterwards
-       
-       ShutDownEventQueue();
-
-       CtdlThreadNode *this_thread;
-       
-       begin_critical_section(S_THREAD_LIST);
-       this_thread = CtdlThreadList;
-       // Ask the GC thread to stop first so everything knows we are shutting down.
-       GC_thread->state = CTDL_THREAD_STOP_REQ;
-       while(this_thread)
-       {
-               if (!citthread_equal(this_thread->tid, GC_thread->tid))
-                       citthread_kill(this_thread->tid, SIGHUP);
-
-               ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
-               citthread_cond_signal(&this_thread->ThreadCond);
-               citthread_cond_signal(&this_thread->SleepCond);
-               this_thread->stop_ticker = time(NULL);
-               syslog(LOG_DEBUG, "Thread system stopping thread \"%s\" (0x%08lx).\n",
-                       this_thread->name, this_thread->tid);
-               this_thread = this_thread->next;
-       }
-       end_critical_section(S_THREAD_LIST);
-}
-
-
-/*
- * A function to wake up all sleeping threads
- */
-void CtdlThreadWakeAll(void)
-{
-       CtdlThreadNode *this_thread;
-       
-       syslog(LOG_DEBUG, "Thread system waking all threads.\n");
-       
-       begin_critical_section(S_THREAD_LIST);
-       this_thread = CtdlThreadList;
-       while(this_thread)
-       {
-               if (!this_thread->thread_func)
-               {
-                       citthread_cond_signal(&this_thread->ThreadCond);
-                       citthread_cond_signal(&this_thread->SleepCond);
-               }
-               this_thread = this_thread->next;
-       }
-       end_critical_section(S_THREAD_LIST);
-}
-
-
-/*
- * A function to return the number of threads running in the system
- */
-int CtdlThreadGetCount(void)
-{
-       return  num_threads;
-}
-
-int CtdlThreadGetWorkers(void)
-{
-       return  num_workers;
-}
-
-double CtdlThreadGetWorkerAvg(void)
-{
-       double ret;
-       
-       begin_critical_section(S_THREAD_LIST);
-       ret =  CtdlThreadWorkerAvg;
-       end_critical_section(S_THREAD_LIST);
-       return ret;
-}
-
-double CtdlThreadGetLoadAvg(void)
-{
-       double load_avg[3] = {0.0, 0.0, 0.0};
-
-       int ret = 0;
-       int smp_num_cpus;
-
-       /* Borrowed this straight from procps */
-       smp_num_cpus = sysconf(_SC_NPROCESSORS_ONLN);
-       if(smp_num_cpus<1) smp_num_cpus=1; /* SPARC glibc is buggy */
-
-#ifdef HAVE_GETLOADAVG
-       ret = getloadavg(load_avg, 3);
-#endif
-       if (ret < 0)
-               return 0;
-       return load_avg[0] / smp_num_cpus;
-/*
- * This old chunk of code return a value that indicated the load on citserver
- * This value could easily reach 100 % even when citserver was doing very little and
- * hence the machine has much more spare capacity.
- * Because this value was used to determine if the machine was under heavy load conditions
- * from other processes in the system then citserver could be strangled un-necesarily
- * What we are actually trying to achieve is to strangle citserver if the machine is heavily loaded.
- * So we have changed this.
-
-       begin_critical_section(S_THREAD_LIST);
-       ret =  CtdlThreadLoadAvg;
-       end_critical_section(S_THREAD_LIST);
-       return ret;
-*/
-}
-
-
-
-
-/*
- * A function to rename a thread
- * Returns a const char *
- */
-const char *CtdlThreadName(const char *name)
-{
-       const char *old_name;
-       
-       if (!CT)
-       {
-               syslog(LOG_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
-               return NULL;
-       }
-       old_name = CT->name;
-       if (name)
-               CT->name = name;
-       return (old_name);
-}      
-
-
-/*
- * A function to force a thread to exit
- */
-void CtdlThreadCancel(CtdlThreadNode *thread)
-{
-       CtdlThreadNode *this_thread;
-       
-       if (!thread)
-               this_thread = CT;
-       else
-               this_thread = thread;
-       if (!this_thread)
-       {
-               syslog(LOG_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
-               CtdlThreadStopAll();
-               return;
-       }
-       
-       if (!this_thread->thread_func)
-       {
-               syslog(LOG_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
-               CtdlThreadStopAll();
-               return;
-       }
-       
-       ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
-       citthread_cancel(this_thread->tid);
+       terminate_all_sessions();               /* close all client sockets */
+       CtdlShutdownServiceHooks();             /* close all listener sockets to prevent new connections */
+       PerformSessionHooks(EVT_SHUTDOWN);      /* run any registered shutdown hooks */
 }
 
 
@@ -485,766 +155,99 @@ void CtdlThreadCancel(CtdlThreadNode *thread)
  */
 int CtdlThreadCheckStop(void)
 {
-       int state;
-       
-       if (!CT)
-       {
-               syslog(LOG_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
-               CtdlThreadStopAll();
-               return -1;
-       }
-       
-       state = CT->state;
-
-       if (CT->signal)
-       {
-               syslog(LOG_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
-               if (CT->signal == SIGHUP)
-                       CT->state = CTDL_THREAD_STOP_REQ;
-               CT->signal = 0;
-       }
-       if(state == CTDL_THREAD_STOP_REQ)
-       {
-               CT->state = CTDL_THREAD_STOPPING;
-               return -1;
-       }
-       else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
-       {
-               return -1;
-       }
-       return 0;
-}
-
-
-/*
- * A function to ask a thread to exit
- * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
- */
-void CtdlThreadStop(CtdlThreadNode *thread)
-{
-       CtdlThreadNode *this_thread;
-       
-       if (!thread)
-               this_thread = CT;
-       else
-               this_thread = thread;
-       if (!this_thread)
-               return;
-       if (!(this_thread->thread_func))
-               return;         // Don't stop garbage collector
 
-       if (!citthread_equal(this_thread->tid, GC_thread->tid))
-               citthread_kill(this_thread->tid, SIGHUP);
+       /* FIXME this needs to do something useful.  moar code pls ! */
 
-       ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
-       citthread_cond_signal(&this_thread->ThreadCond);
-       citthread_cond_signal(&this_thread->SleepCond);
-       this_thread->stop_ticker = time(NULL);
-}
-
-/*
- * So we now have a sleep command that works with threads but it is in seconds
- */
-void CtdlThreadSleep(int secs)
-{
-       struct timespec wake_time;
-       struct timeval time_now;
-       
-       
-       if (!CT)
-       {
-               syslog(LOG_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
-               return;
-       }
-       
-       memset (&wake_time, 0, sizeof(struct timespec));
-       gettimeofday(&time_now, NULL);
-       wake_time.tv_sec = time_now.tv_sec + secs;
-       wake_time.tv_nsec = time_now.tv_usec * 10;
-
-       ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
-       
-       citthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
-       citthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
-       citthread_mutex_unlock(&CT->ThreadMutex);
-       
-       ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
-}
-
-
-/*
- * Routine to clean up our thread function on exit
- */
-static void ctdl_internal_thread_cleanup(void *arg)
-{
-       /*
-        * In here we were called by the current thread because it is exiting
-        * NB. WE ARE THE CURRENT THREAD
-        */
-       if (CT)
-       {
-               const char *name = CT->name;
-               const pid_t tid = CT->tid;
-
-               syslog(LOG_NOTICE, "Thread \"%s\" (0x%08lx) exited.\n", name, (unsigned long) tid);
-       }
-       else 
-       {
-               syslog(LOG_NOTICE, "some ((unknown ? ? ?) Thread exited.\n");
-       }
-       
-       #ifdef HAVE_BACKTRACE
-///    eCrash_UnregisterThread();
-       #endif
-       
-       citthread_mutex_lock(&CT->ThreadMutex);
-       CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
-       citthread_mutex_unlock(&CT->ThreadMutex);
-}
-
-/*
- * Garbage collection routine.
- * Gets called by main() in a loop to clean up the thread list periodically.
- */
-void CtdlThreadGC (void)
-{
-
-
-       return;
-       /* FIXME this is a big deal, but I think it's causing corruption */
-
-
-       CtdlThreadNode *this_thread, *that_thread;
-       int workers = 0, sys_workers;
-       int ret=0;
-
-       begin_critical_section(S_THREAD_LIST);
-       
-       /* Handle exiting of garbage collector thread */
-       if(num_threads == 1)
-               CtdlThreadList->state = CTDL_THREAD_EXITED;
-       
-#ifdef WITH_THREADLOG
-       syslog(LOG_DEBUG, "Thread system running garbage collection.\n");
-#endif
-       /*
-        * Woke up to do garbage collection
-        */
-       this_thread = CtdlThreadList;
-       while(this_thread)
-       {
-               that_thread = this_thread;
-               this_thread = this_thread->next;
-               
-               if ((that_thread->state == CTDL_THREAD_STOP_REQ || that_thread->state == CTDL_THREAD_STOPPING)
-                       && (!citthread_equal(that_thread->tid, citthread_self())))
-               {
-                       syslog(LOG_DEBUG, "Waiting for thread %s (0x%08lx) to exit.\n", that_thread->name, that_thread->tid);
-                       terminate_stuck_sessions();
-               }
-               else
-               {
-                       /**
-                        * Catch the situation where a worker was asked to stop but couldn't and we are not
-                        * shutting down.
-                        */
-                       that_thread->stop_ticker = 0;
-               }
-               
-               if (that_thread->stop_ticker + 5 == time(NULL))
-               {
-                       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);
-                       if ((that_thread->flags & CTDLTHREAD_WORKER) == 0)
-                               syslog(LOG_INFO, "Thread System: A non worker thread would have been canceled this may cause message loss.\n");
-//                     that_thread->state = CTDL_THREAD_CANCELLED;
-                       that_thread->stop_ticker++;
-//                     citthread_cancel(that_thread->tid);
-//                     continue;
-               }
-               
-               /* Do we need to clean up this thread? */
-               if ((that_thread->state != CTDL_THREAD_EXITED) && (that_thread->state != CTDL_THREAD_CANCELLED))
-               {
-                       if(that_thread->flags & CTDLTHREAD_WORKER)
-                               workers++;      /* Sanity check on number of worker threads */
-                       continue;
-               }
-               
-               if (citthread_equal(that_thread->tid, citthread_self()) && that_thread->thread_func)
-               {       /* Sanity check */
-                       end_critical_section(S_THREAD_LIST);
-                       syslog(LOG_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
-                       abort();
-                       return;
-               }
-               
-               if (num_threads <= 0)
-               {       /* Sanity check */
-                       end_critical_section(S_THREAD_LIST);
-                       syslog(LOG_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
-                       abort();
-                       return;
-               }
-
-               if(that_thread->flags & CTDLTHREAD_WORKER)
-                       num_workers--;  /* This is a wroker thread so reduce the count. */
-               num_threads--;
-               /* If we are unlinking the list head then the next becomes the list head */
-               if(that_thread->prev)
-                       that_thread->prev->next = that_thread->next;
-               else
-                       CtdlThreadList = that_thread->next;
-               if(that_thread->next)
-                       that_thread->next->prev = that_thread->prev;
-               
-               citthread_cond_signal(&that_thread->ThreadCond);
-               citthread_cond_signal(&that_thread->SleepCond); // Make sure this thread is awake
-               citthread_mutex_lock(&that_thread->ThreadMutex);        // Make sure it has done what its doing
-               citthread_mutex_unlock(&that_thread->ThreadMutex);
-               /*
-                * Join on the thread to do clean up and prevent memory leaks
-                * Also makes sure the thread has cleaned up after itself before we remove it from the list
-                * We can join on the garbage collector thread the join should just return EDEADLCK
-                */
-               ret = citthread_join (that_thread->tid, NULL);
-               if (ret == EDEADLK)
-                       syslog(LOG_DEBUG, "Garbage collection on own thread.\n");
-               else if (ret == EINVAL)
-                       syslog(LOG_DEBUG, "Garbage collection, that thread already joined on.\n");
-               else if (ret == ESRCH)
-                       syslog(LOG_DEBUG, "Garbage collection, no thread to join on.\n");
-               else if (ret != 0)
-                       syslog(LOG_DEBUG, "Garbage collection, citthread_join returned an unknown error(%d).\n", ret);
-               /*
-                * Now we own that thread entry
-                */
-               syslog(LOG_INFO, "Garbage Collection for thread \"%s\" (0x%08lx).\n",
-                       that_thread->name, that_thread->tid);
-               citthread_mutex_destroy(&that_thread->ThreadMutex);
-               citthread_cond_destroy(&that_thread->ThreadCond);
-               citthread_mutex_destroy(&that_thread->SleepMutex);
-               citthread_cond_destroy(&that_thread->SleepCond);
-               citthread_attr_destroy(&that_thread->attr);
-               free(that_thread);
-       }
-       sys_workers = num_workers;
-       end_critical_section(S_THREAD_LIST);
-       
-       /* Sanity check number of worker threads */
-       if (workers != sys_workers)
-       {
-               syslog(LOG_EMERG,
-                       "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
-                       workers, sys_workers
-                       );
-               abort();
-       }
+       return 0;
 }
 
 
-
 /*
- * Runtime function for a Citadel Thread.
- * This initialises the threads environment and then calls the user supplied thread function
- * Note that this is the REAL thread function and wraps the users thread function.
+ * Return a pointer to our thread-specific (not session-specific) data.
  */ 
-static void *ctdl_internal_thread_func (void *arg)
-{
-       CtdlThreadNode *this_thread;
-       void *ret = NULL;
-
-       /* lock and unlock the thread list.
-        * This causes this thread to wait until all its creation stuff has finished before it
-        * can continue its execution.
-        */
-       begin_critical_section(S_THREAD_LIST);
-       this_thread = (CtdlThreadNode *) arg;
-       gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
-       
-       // Register the cleanup function to take care of when we exit.
-       citthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
-       // Get our thread data structure
-       CtdlThreadAllocTSD();
-       CT = this_thread;
-       this_thread->pid = getpid();
-       memcpy(&this_thread->last_state_change, &this_thread->start_time, sizeof (struct timeval));     /* Changed state so mark it. */
-       /* Only change to running state if we weren't asked to stop during the create cycle
-        * Other wise there is a window to allow this threads creation to continue to full grown and
-        * therby prevent a shutdown of the server.
-        */
-       if (!CtdlThreadCheckStop())
-       {
-               citthread_mutex_lock(&this_thread->ThreadMutex);
-               this_thread->state = CTDL_THREAD_RUNNING;
-               citthread_mutex_unlock(&this_thread->ThreadMutex);
-       }
-       end_critical_section(S_THREAD_LIST);
-       
-       // Register for tracing
-       #ifdef HAVE_BACKTRACE
-///    eCrash_RegisterThread(this_thread->name, 0);
-       #endif
-       
-       // Tell the world we are here
-#if defined(HAVE_SYSCALL_H) && defined (SYS_gettid)
-       this_thread->reltid = syscall(SYS_gettid);
-#endif
-       syslog(LOG_NOTICE, "Created a new thread \"%s\" (0x%08lx).\n",
-               this_thread->name, this_thread->tid);
-       
-       /*
-        * run the thread to do the work but only if we haven't been asked to stop
-        */
-       if (!CtdlThreadCheckStop())
-               ret = (this_thread->thread_func)(this_thread->user_args);
-       
-       /*
-        * Our thread is exiting either because it wanted to end or because the server is stopping
-        * We need to clean up
-        */
-       citthread_cleanup_pop(1);       // Execute our cleanup routine and remove it
-       
-       return(ret);
+struct thread_tsd *MyThread(void) {
+        register struct thread_tsd *c;
+        return ((c = (struct thread_tsd *) pthread_getspecific(ThreadKey), c == NULL) ? &masterTSD : c);
 }
 
 
 
-
-/*
- * Function to initialise an empty thread structure
+/* 
+ * Called by CtdlThreadCreate()
+ * We have to pass through here before starting our thread in order to create a set of data
+ * that is thread-specific rather than session-specific.
  */
-CtdlThreadNode *ctdl_internal_init_thread_struct(CtdlThreadNode *this_thread, long flags)
+void *CTC_backend(void *supplied_start_routine)
 {
-       int ret = 0;
-       
-       // Ensuring this is zero'd means we make sure the thread doesn't start doing its thing until we are ready.
-       memset (this_thread, 0, sizeof(CtdlThreadNode));
-       
-       /* Create the mutex's early so we can use them */
-       citthread_mutex_init (&(this_thread->ThreadMutex), NULL);
-       citthread_cond_init (&(this_thread->ThreadCond), NULL);
-       citthread_mutex_init (&(this_thread->SleepMutex), NULL);
-       citthread_cond_init (&(this_thread->SleepCond), NULL);
-       
-       this_thread->state = CTDL_THREAD_CREATE;
-       
-       if ((ret = citthread_attr_init(&this_thread->attr))) {
-               citthread_mutex_unlock(&this_thread->ThreadMutex);
-               citthread_mutex_destroy(&(this_thread->ThreadMutex));
-               citthread_cond_destroy(&(this_thread->ThreadCond));
-               citthread_mutex_destroy(&(this_thread->SleepMutex));
-               citthread_cond_destroy(&(this_thread->SleepCond));
-               syslog(LOG_EMERG, "Thread system, citthread_attr_init: %s\n", strerror(ret));
-               free(this_thread);
-               return NULL;
-       }
-
-       /* Our per-thread stacks need to be bigger than the default size,
-        * otherwise the MIME parser crashes on FreeBSD, and the IMAP service
-        * crashes on 64-bit Linux.
-        */
-       if (flags & CTDLTHREAD_BIGSTACK)
-       {
-#ifdef WITH_THREADLOG
-               syslog(LOG_INFO, "Thread system. Creating BIG STACK thread.\n");
-#endif
-               if ((ret = citthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
-                       citthread_mutex_unlock(&this_thread->ThreadMutex);
-                       citthread_mutex_destroy(&(this_thread->ThreadMutex));
-                       citthread_cond_destroy(&(this_thread->ThreadCond));
-                       citthread_mutex_destroy(&(this_thread->SleepMutex));
-                       citthread_cond_destroy(&(this_thread->SleepCond));
-                       citthread_attr_destroy(&this_thread->attr);
-                       syslog(LOG_EMERG, "Thread system, citthread_attr_setstacksize: %s\n",
-                               strerror(ret));
-                       free(this_thread);
-                       return NULL;
-               }
-       }
+       struct thread_tsd *mytsd;
+       void *(*start_routine)(void*) = supplied_start_routine;
 
-       /* Set this new thread with an avg_blocked of 2. We do this so that its creation affects the
-        * load average for the system. If we don't do this then we create a mass of threads at the same time 
-        * because the creation didn't affect the load average.
-        */
-       this_thread->avg_blocked = 2;
-       
-       return (this_thread);
-}
+       mytsd = (struct thread_tsd *) malloc(sizeof(struct thread_tsd));
+       memset(mytsd, 0, sizeof(struct thread_tsd));
+       pthread_setspecific(ThreadKey, (const void *) mytsd);
 
+       start_routine(NULL);
 
+       return(NULL);
+}
 
  
 /*
- * Internal function to create a thread.
+ * Function to create a thread.
  */ 
-CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
+void CtdlThreadCreate(void *(*start_routine)(void*))
 {
+       pthread_t thread;
+       pthread_attr_t attr;
        int ret = 0;
-       CtdlThreadNode *this_thread;
-
-       if (num_threads >= 32767)
-       {
-               syslog(LOG_EMERG, "Thread system. Thread list full.\n");
-               return NULL;
-       }
-               
-       this_thread = malloc(sizeof(CtdlThreadNode));
-       if (this_thread == NULL) {
-               syslog(LOG_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
-               return NULL;
-       }
-       
-       /* Initialise the thread structure */
-       if (ctdl_internal_init_thread_struct(this_thread, flags) == NULL)
-       {
-               free(this_thread);
-               syslog(LOG_EMERG, "Thread system, can't initialise CtdlThreadNode, exiting\n");
-               return NULL;
-       }
-       /*
-        * If we got here we are going to create the thread so we must initilise the structure
-        * first because most implimentations of threading can't create it in a stopped state
-        * and it might want to do things with its structure that aren't initialised otherwise.
-        */
-       if(name)
-       {
-               this_thread->name = name;
-       }
-       else
-       {
-               this_thread->name = "Un-named Thread";
-       }
-       
-       this_thread->flags = flags;
-       this_thread->thread_func = thread_func;
-       this_thread->user_args = args;
-       
-       begin_critical_section(S_THREAD_LIST);
-       /*
-        * We pass this_thread into the thread as its args so that it can find out information
-        * about itself and it has a bit of storage space for itself, not to mention that the REAL
-        * thread function needs to finish off the setup of the structure
-        */
-       if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
-       {
-               end_critical_section(S_THREAD_LIST);
-               syslog(LOG_ALERT, "Thread system, Can't create thread: %s\n",
-                       strerror(ret));
-               citthread_mutex_unlock(&this_thread->ThreadMutex);
-               citthread_mutex_destroy(&(this_thread->ThreadMutex));
-               citthread_cond_destroy(&(this_thread->ThreadCond));
-               citthread_mutex_destroy(&(this_thread->SleepMutex));
-               citthread_cond_destroy(&(this_thread->SleepCond));
-               citthread_attr_destroy(&this_thread->attr);
-               free(this_thread);
-               return NULL;
-       }
-       num_threads++;  // Increase the count of threads in the system.
-       if(this_thread->flags & CTDLTHREAD_WORKER)
-               num_workers++;
-
-       this_thread->next = CtdlThreadList;
-       CtdlThreadList = this_thread;
-       if (this_thread->next)
-               this_thread->next->prev = this_thread;
-       
-       end_critical_section(S_THREAD_LIST);
-       
-       return this_thread;
-}
-
-/*
- * Wrapper function to create a thread
- * ensures the critical section and other protections are in place.
- * char *name = name to give to thread, if NULL, use generic name
- * int flags = flags to determine type of thread and standard facilities
- */
-CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
-{
-       CtdlThreadNode *ret = NULL;
-       
-       ret = ctdl_internal_create_thread(name, flags, thread_func, args);
-       return ret;
-}
 
 
+       ret = pthread_attr_init(&attr);
+       ret = pthread_attr_setstacksize(&attr, THREADSTACKSIZE);
+       ret = pthread_create(&thread, &attr, CTC_backend, (void *)start_routine);
+       if (ret != 0) syslog(LOG_EMERG, "pthread_create() : %s", strerror(errno));
 
-CtdlThreadNode *ctdl_thread_internal_start_scheduled (CtdlThreadNode *this_thread)
-{
-       int ret = 0;
-       
-       begin_critical_section(S_THREAD_LIST);
-       /*
-        * We pass this_thread into the thread as its args so that it can find out information
-        * about itself and it has a bit of storage space for itself, not to mention that the REAL
-        * thread function needs to finish off the setup of the structure
-        */
-       if ((ret = citthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
-       {
-               end_critical_section(S_THREAD_LIST);
-               syslog(LOG_DEBUG, "Failed to start scheduled thread \"%s\": %s\n", this_thread->name, strerror(ret));
-               citthread_mutex_destroy(&(this_thread->ThreadMutex));
-               citthread_cond_destroy(&(this_thread->ThreadCond));
-               citthread_mutex_destroy(&(this_thread->SleepMutex));
-               citthread_cond_destroy(&(this_thread->SleepCond));
-               citthread_attr_destroy(&this_thread->attr);
-               free(this_thread);
-               return NULL;
-       }
-       
-       
-       num_threads++;  // Increase the count of threads in the system.
-       if(this_thread->flags & CTDLTHREAD_WORKER)
-               num_workers++;
-
-       this_thread->next = CtdlThreadList;
-       CtdlThreadList = this_thread;
-       if (this_thread->next)
-               this_thread->next->prev = this_thread;
-       
-       end_critical_section(S_THREAD_LIST);
-       
-       
-       return this_thread;
+       ++num_threads;
 }
 
 
-
-void ctdl_thread_internal_check_scheduled(void)
-{
-       CtdlThreadNode *this_thread, *that_thread;
-       time_t now;
-       
-       /* Don't start scheduled threads if the system wants single user mode */
-       if (CtdlWantSingleUser())
-               return;
-       
-       if (try_critical_section(S_SCHEDULE_LIST))
-               return; /* If this list is locked we wait till the next chance */
-       
-       now = time(NULL);
-       
-#ifdef WITH_THREADLOG
-       syslog(LOG_DEBUG, "Checking for scheduled threads to start.\n");
-#endif
-
-       this_thread = CtdlThreadSchedList;
-       while(this_thread)
-       {
-               that_thread = this_thread;
-               this_thread = this_thread->next;
-               
-               if (now > that_thread->when)
-               {
-                       /* Unlink from schedule list */
-                       if (that_thread->prev)
-                               that_thread->prev->next = that_thread->next;
-                       else
-                               CtdlThreadSchedList = that_thread->next;
-                       if (that_thread->next)
-                               that_thread->next->prev = that_thread->prev;
-                               
-                       that_thread->next = that_thread->prev = NULL;
-#ifdef WITH_THREADLOG
-                       syslog(LOG_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
-#endif
-                       if (CT->state > CTDL_THREAD_STOP_REQ)
-                       {       /* Only start it if the system is not stopping */
-                               if (ctdl_thread_internal_start_scheduled (that_thread))
-                               {
-#ifdef WITH_THREADLOG
-                                       syslog(LOG_INFO, "Thread system, Started a scheduled thread \"%s\" (0x%08lx).\n",
-                                               that_thread->name, that_thread->tid);
-#endif
-                               }
-                       }
-               }
-#ifdef WITH_THREADLOG
-               else
-               {
-                       syslog(LOG_DEBUG, "Thread \"%s\" will start in %ld seconds.\n",
-                               that_thread->name, that_thread->when - time(NULL));
-               }
-#endif
-       }
-       end_critical_section(S_SCHEDULE_LIST);
+void InitializeMasterTSD(void) {
+       memset(&masterTSD, 0, sizeof(struct thread_tsd));
 }
 
 
 /*
- * A warapper function for select so we can show a thread as blocked
+ * Initialize the thread system
  */
-int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout)
-{
-       int ret = 0;
-       
-       ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
-       if (!CtdlThreadCheckStop())
-               ret = select(n, readfds, writefds, exceptfds, timeout);
-       /**
-        * If the select returned <= 0 then it failed due to an error
-        * or timeout so this thread could stop if asked to do so.
-        * Anything else means it needs to continue unless the system is shutting down
-        */
-       if (ret > 0)
-       {
-               /**
-                * The select says this thread needs to do something useful.
-                * This thread was in an idle state so it may have been asked to stop
-                * but if the system isn't shutting down this thread is no longer
-                * idle and select has given it a task to do so it must not stop
-                * In this condition we need to force it into the running state.
-                * CtdlThreadGC will clear its ticker for us.
-                *
-                * FIXME: there is still a small hole here. It is possible for the sequence of locking
-                * to allow the state to get changed to STOP_REQ just after this code if the other thread
-                * has decided to change the state before this lock, it there fore has to wait till the lock
-                * completes but it will continue to change the state. We need something a bit better here.
-                */
-               citthread_mutex_lock(&CT->ThreadMutex); /* To prevent race condition of a sleeping thread */
-               if (GC_thread->state > CTDL_THREAD_STOP_REQ && CT->state <= CTDL_THREAD_STOP_REQ)
-               {
-                       syslog(LOG_DEBUG, "Thread %s (0x%08lx) refused stop request.\n", CT->name, CT->tid);
-                       CT->state = CTDL_THREAD_RUNNING;
-               }
-               citthread_mutex_unlock(&CT->ThreadMutex);
-       }
-
-       ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
-
-       return ret;
-}
-
-
-
-void *new_worker_thread(void *arg);
-extern void close_masters (void);
-
-
-
 void go_threading(void)
 {
-       int i;
-       CtdlThreadNode *last_worker;
-
-       /*
-        * Initialise the thread system
-        */
-       ctdl_thread_internal_init();
+       if (pthread_key_create(&ThreadKey, NULL) != 0) {
+               syslog(LOG_EMERG, "pthread_key_create() : %s", strerror(errno));
+               abort();
+       }
 
        /* Second call to module init functions now that threading is up */
        initialise_modules(1);
-       CtdlThreadCreate("select_on_master", CTDLTHREAD_BIGSTACK, select_on_master, NULL);
 
-       /*
-        * This thread is now used for garbage collection of other threads in the thread list
-        */
-       syslog(LOG_INFO, "Startup thread %ld becoming garbage collector,\n", (long) citthread_self());
+       CtdlThreadCreate(select_on_master);
 
-       /*
-        * We do a lot of locking and unlocking of the thread list in here.
-        * We do this so that we can repeatedly release time for other threads
-        * that may be waiting on the thread list.
-        * We are a low priority thread so we can afford to do this
-        */
-       
-       while (CtdlThreadGetCount())
-       {
-               if (CT->signal)
-                       exit_signal = CT->signal;
-               if (exit_signal)
-               {
-                       CtdlThreadStopAll();
-               }
-               check_sched_shutdown();
-               if (CT->state > CTDL_THREAD_STOP_REQ)
-               {
-                       begin_critical_section(S_THREAD_LIST);
-                       end_critical_section(S_THREAD_LIST);
-                       
-                       ctdl_thread_internal_check_scheduled(); /* start scheduled threads */
-               }
-               
-               /* Reduce the size of the worker thread pool if necessary. */
-               if ((CtdlThreadGetWorkers() > config.c_min_workers + 1) && (CtdlThreadWorkerAvg < 20) && (CT->state > CTDL_THREAD_STOP_REQ))
-               {
-                       /* Ask a worker thread to stop as we no longer need it */
-                       begin_critical_section(S_THREAD_LIST);
-                       last_worker = CtdlThreadList;
-                       while (last_worker)
-                       {
-                               citthread_mutex_lock(&last_worker->ThreadMutex);
-                               if (last_worker->flags & CTDLTHREAD_WORKER && (last_worker->state > CTDL_THREAD_STOPPING) && (last_worker->Context == NULL))
-                               {
-                                       citthread_mutex_unlock(&last_worker->ThreadMutex);
-                                       break;
-                               }
-                               citthread_mutex_unlock(&last_worker->ThreadMutex);
-                               last_worker = last_worker->next;
-                       }
-                       end_critical_section(S_THREAD_LIST);
-                       if (last_worker)
-                       {
-#ifdef WITH_THREADLOG
-                               syslog(LOG_DEBUG, "Thread system, stopping excess worker thread \"%s\" (0x%08lx).\n",
-                                       last_worker->name,
-                                       last_worker->tid
-                                       );
-#endif
-                               CtdlThreadStop(last_worker);
-                       }
-               }
-       
-               /*
-                * If all our workers are working hard, start some more to help out
-                * with things
-                */
-               /* FIXME: come up with a better way to dynamically alter the number of threads
-                * based on the system load
-                */
-               if (    (((CtdlThreadGetWorkers() < config.c_max_workers)
-                       && (CtdlThreadGetWorkerAvg() > 60))
-                       || CtdlThreadGetWorkers() < config.c_min_workers)
-                       && (CT->state > CTDL_THREAD_STOP_REQ)
-               )
-               {
-                       /* Only start new threads if we are not going to overload the machine */
-                       /* Temporarily set to 10 should be enough to make sure we don't stranglew the server
-                        * at least until we make this a config option */
-                       if (CtdlThreadGetLoadAvg() < ((double)10.00)) {
-                               for (i=0; i<5 ; i++) {
-                                       CtdlThreadCreate("Worker Thread",
-                                               CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER,
-                                               worker_thread,
-                                               NULL
-                                               );
-                               }
-                       }
-                       else
-                               syslog(LOG_WARNING, "Server strangled due to machine load average too high.\n");
-               }
+       /* FIXME temporary fixed size pool of worker threads */
+       CtdlThreadCreate(worker_thread);
+       CtdlThreadCreate(worker_thread);
+       CtdlThreadCreate(worker_thread);
+       CtdlThreadCreate(worker_thread);
+       CtdlThreadCreate(worker_thread);
+       CtdlThreadCreate(worker_thread);
+       CtdlThreadCreate(worker_thread);
+       CtdlThreadCreate(worker_thread);
 
-               CtdlThreadGC();
+       /* At this point I am a union worker and therefore serve no useful purpose. */
 
-               if (CtdlThreadGetCount() <= 1) // Shutting down clean up the garbage collector
-               {
-                       CtdlThreadGC();
-               }
-               
-#ifdef THREADS_USESIGNALS
-               if (CtdlThreadGetCount() && CT->state > CTDL_THREAD_STOP_REQ)
-#else
-               if (CtdlThreadGetCount())
-#endif
-                       CtdlThreadSleep(1);
+       while(!CtdlThreadCheckStop()) {
+               sleep(3);
        }
-       /*
-        * If the above loop exits we must be shutting down since we obviously have no threads
-        */
-       ctdl_thread_internal_cleanup();
-}
-
-
-
 
+       /* Shut down */
+       CtdlThreadStopAll();
+       exit(0);
+}