]> code.citadel.org Git - citadel.git/blobdiff - citadel/sysdep.c
Added the functions to allow scheduling of a thread to start at some
[citadel.git] / citadel / sysdep.c
index 268196996dccec6d35755861205b1e007c20ba7e..17e40ce57482ea80b1c1dac65ded41b3b676052e 100644 (file)
@@ -789,6 +789,11 @@ void context_cleanup(void)
         * There are no threads so no critical_section stuff is needed.
         */
        ptr = ContextList;
+       
+       /* We need to update the ContextList because some modules may want to itterate it
+        * Question is should we NULL it before iterating here or should we just keep updating it
+        * as we remove items?
+        */
        while (ptr != NULL){
                /* Remove the session from the active list */
                rem = ptr->next;
@@ -798,8 +803,8 @@ void context_cleanup(void)
                RemoveContext(ptr);
                free (ptr);
                ptr = rem;
+               ContextList = rem; // Update ContextList since a module may try to iterate the list.
        }
-       
 }
 
 
@@ -1009,6 +1014,7 @@ int convert_login(char NameToConvert[]) {
 
 
 struct CtdlThreadNode *CtdlThreadList = NULL;
+struct CtdlThreadNode *CtdlThreadSchedList = NULL;
 
 /*
  * Condition variable and Mutex for thread garbage collection
@@ -1020,70 +1026,89 @@ static pthread_t GC_thread;
 static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
 double CtdlThreadLoadAvg = 0;
 double CtdlThreadWorkerAvg = 0;
+pthread_key_t ThreadKey;
+
 /*
- * Pinched the following bits regarding signals from Kannel.org
+ * A function to destroy the TSD
  */
+static void ctdl_thread_internal_dest_tsd(void *arg)
+{
+       if (arg != NULL) {
+               check_handles(arg);
+               free(arg);
+       }
+}
+
+
 /*
- * Change this thread's signal mask to block user-visible signals
- * (HUP, TERM, QUIT, INT), and store the old signal mask in
- * *old_set_storage.
- * Return 0 for success, or -1 if an error occurred.
+ * A function to initialise the thread TSD
  */
- /* 
-  * This does not work in Darwin alias MacOS X alias Mach kernel,
-  * however. So we define a dummy function doing nothing.
-  */
-#if defined(DARWIN_OLD)
-    static int pthread_sigmask();
-#endif
-  
-static int ctdl_thread_internal_block_signals(sigset_t *old_set_storage)
+void ctdl_thread_internal_init_tsd(void)
 {
-    int ret;
-    sigset_t block_signals;
-
-    ret = sigemptyset(&block_signals);
-    if (ret != 0) {
-        CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Couldn't initialize signal set\n");
-           return -1;
-    }
-    ret = sigaddset(&block_signals, SIGHUP);
-    ret |= sigaddset(&block_signals, SIGTERM);
-    ret |= sigaddset(&block_signals, SIGQUIT);
-    ret |= sigaddset(&block_signals, SIGINT);
-    if (ret != 0) {
-        CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Couldn't add signal to signal set.\n");
-           return -1;
-    }
-    ret = pthread_sigmask(SIG_BLOCK, &block_signals, old_set_storage);
-    if (ret != 0) {
-        CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Couldn't disable signals for thread creation\n");
-        return -1;
-    }
-    return 0;
-}
-
-static void ctdl_thread_internal_restore_signals(sigset_t *old_set)
+       int ret;
+       
+       if ((ret = pthread_key_create(&ThreadKey, ctdl_thread_internal_dest_tsd))) {
+               lprintf(CTDL_EMERG, "pthread_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)
 {
-    int ret;
+       ThreadTSD *tsd;
+
+       if (pthread_getspecific(ThreadKey) != NULL)
+               return;
+
+       tsd = malloc(sizeof(ThreadTSD));
+
+       tsd->tid = NULL;
+
+       memset(tsd->cursors, 0, sizeof tsd->cursors);
+       tsd->self = NULL;
+       
+       pthread_setspecific(ThreadKey, tsd);
+}
+
 
-    ret = pthread_sigmask(SIG_SETMASK, old_set, NULL);
-    if (ret != 0) {
-        CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Couldn't restore signal set.\n");
-    }
+void ctdl_thread_internal_free_tsd(void)
+{
+       ctdl_thread_internal_dest_tsd(pthread_getspecific(ThreadKey));
+       pthread_setspecific(ThreadKey, NULL);
 }
 
 
 void ctdl_thread_internal_cleanup(void)
 {
        int i;
+       struct 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;
+               pthread_mutex_destroy(&that_thread->ThreadMutex);
+               pthread_cond_destroy(&that_thread->ThreadCond);
+               pthread_mutex_destroy(&that_thread->SleepMutex);
+               pthread_cond_destroy(&that_thread->SleepCond);
+               pthread_attr_destroy(&that_thread->attr);
+               free(that_thread);
+       }
+       ctdl_thread_internal_free_tsd();
 }
 
 void ctdl_thread_internal_init(void)
@@ -1129,6 +1154,7 @@ void ctdl_thread_internal_init(void)
        this_thread->name = "Garbage Collection Thread";
        
        this_thread->tid = GC_thread;
+       CT = this_thread;
        
        num_threads++;  // Increase the count of threads in the system.
 
@@ -1199,15 +1225,10 @@ void CtdlThreadStopAll(void)
        this_thread = CtdlThreadList;
        while(this_thread)
        {
-               if (this_thread->thread_func) // Don't tell garbage collector to stop
-               {
-                       ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
-//                     pthread_mutex_lock(&this_thread->ThreadMutex);
-                       pthread_cond_signal(&this_thread->ThreadCond);
-                       pthread_cond_signal(&this_thread->SleepCond);
-//                     pthread_mutex_unlock(&this_thread->ThreadMutex);
-                       CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (%ld).\n", this_thread->name, this_thread->tid);
-               }
+               ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
+               pthread_cond_signal(&this_thread->ThreadCond);
+               pthread_cond_signal(&this_thread->SleepCond);
+               CtdlLogPrintf(CTDL_DEBUG, "Thread system stopping thread \"%s\" (%ld).\n", this_thread->name, this_thread->tid);
                this_thread = this_thread->next;
        }
        end_critical_section(S_THREAD_LIST);
@@ -1229,10 +1250,8 @@ void CtdlThreadWakeAll(void)
        {
                if (!this_thread->thread_func)
                {
-//                     pthread_mutex_lock(&this_thread->ThreadMutex);
                        pthread_cond_signal(&this_thread->ThreadCond);
                        pthread_cond_signal(&this_thread->SleepCond);
-//                     pthread_mutex_unlock(&this_thread->ThreadMutex);
                }
                this_thread = this_thread->next;
        }
@@ -1283,34 +1302,6 @@ double CtdlThreadGetLoadAvg(void)
        return ret;
 }
 
-/*
- * A function to find the thread structure for this thread
- */
-struct CtdlThreadNode *CtdlThreadSelf(void)
-{
-       pthread_t self_tid;
-       struct CtdlThreadNode *this_thread;
-       
-       self_tid = pthread_self();
-       
-       begin_critical_section(S_THREAD_LIST);
-       this_thread = CtdlThreadList;
-       while(this_thread)
-       {
-               pthread_mutex_lock(&this_thread->ThreadMutex);
-               if (pthread_equal(self_tid, this_thread->tid))
-               {
-                       pthread_mutex_unlock(&this_thread->ThreadMutex);
-                       end_critical_section(S_THREAD_LIST);
-                       return this_thread;
-               }
-               pthread_mutex_unlock(&this_thread->ThreadMutex);
-               this_thread = this_thread->next;
-       }
-       end_critical_section(S_THREAD_LIST);
-       return NULL;
-}
-
 
 
 
@@ -1318,27 +1309,20 @@ struct CtdlThreadNode *CtdlThreadSelf(void)
  * A function to rename a thread
  * Returns a const char *
  */
-const char *CtdlThreadName(struct CtdlThreadNode *thread, const char *name)
+const char *CtdlThreadName(const char *name)
 {
-       struct CtdlThreadNode *this_thread;
        const char *old_name;
        
-       if (!thread)
-               this_thread = CtdlThreadSelf();
-       else
-               this_thread = thread;
-       if (!this_thread)
+       if (!CT)
        {
                CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
                return NULL;
        }
-//     begin_critical_section(S_THREAD_LIST);
-       pthread_mutex_lock(&this_thread->ThreadMutex);
-       old_name = this_thread->name;
+       pthread_mutex_lock(&CT->ThreadMutex);
+       old_name = CT->name;
        if (name)
-               this_thread->name = name;
-       pthread_mutex_unlock(&this_thread->ThreadMutex);
-//     end_critical_section (S_THREAD_LIST);
+               CT->name = name;
+       pthread_mutex_unlock(&CT->ThreadMutex);
        return (old_name);
 }      
 
@@ -1351,7 +1335,7 @@ void CtdlThreadCancel(struct CtdlThreadNode *thread)
        struct CtdlThreadNode *this_thread;
        
        if (!thread)
-               this_thread = CtdlThreadSelf();
+               this_thread = CT;
        else
                this_thread = thread;
        if (!this_thread)
@@ -1368,10 +1352,8 @@ void CtdlThreadCancel(struct CtdlThreadNode *thread)
                return;
        }
        
-//     begin_critical_section(S_THREAD_LIST);
        ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
        pthread_cancel(this_thread->tid);
-//     end_critical_section (S_THREAD_LIST);
 }
 
 
@@ -1379,27 +1361,27 @@ void CtdlThreadCancel(struct CtdlThreadNode *thread)
 /*
  * A function for a thread to check if it has been asked to stop
  */
-int CtdlThreadCheckStop(struct CtdlThreadNode *this_thread)
+int CtdlThreadCheckStop(void)
 {
-       if (!this_thread)
+       if (!CT)
        {
                CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
                CtdlThreadStopAll();
                return -1;
        }
-       pthread_mutex_lock(&this_thread->ThreadMutex);
-       if(this_thread->state == CTDL_THREAD_STOP_REQ)
+       pthread_mutex_lock(&CT->ThreadMutex);
+       if(CT->state == CTDL_THREAD_STOP_REQ)
        {
-               this_thread->state = CTDL_THREAD_STOPPING;
-               pthread_mutex_unlock(&this_thread->ThreadMutex);
+               CT->state = CTDL_THREAD_STOPPING;
+               pthread_mutex_unlock(&CT->ThreadMutex);
                return -1;
        }
-       else if((this_thread->state < CTDL_THREAD_STOP_REQ) && (this_thread->state > CTDL_THREAD_CREATE))
+       else if((CT->state < CTDL_THREAD_STOP_REQ) && (CT->state > CTDL_THREAD_CREATE))
        {
-               pthread_mutex_unlock(&this_thread->ThreadMutex);
+               pthread_mutex_unlock(&CT->ThreadMutex);
                return -1;
        }
-       pthread_mutex_unlock(&this_thread->ThreadMutex);
+       pthread_mutex_unlock(&CT->ThreadMutex);
        return 0;
 }
 
@@ -1413,7 +1395,7 @@ void CtdlThreadStop(struct CtdlThreadNode *thread)
        struct CtdlThreadNode *this_thread;
        
        if (!thread)
-               this_thread = CtdlThreadSelf();
+               this_thread = CT;
        else
                this_thread = thread;
        if (!this_thread)
@@ -1421,13 +1403,9 @@ void CtdlThreadStop(struct CtdlThreadNode *thread)
        if (!(this_thread->thread_func))
                return;         // Don't stop garbage collector
                
-//     begin_critical_section (S_THREAD_LIST);
        ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
-//     pthread_mutex_lock(&this_thread->ThreadMutex);
        pthread_cond_signal(&this_thread->ThreadCond);
        pthread_cond_signal(&this_thread->SleepCond);
-//     pthread_mutex_unlock(&this_thread->ThreadMutex);
-//     end_critical_section(S_THREAD_LIST);
 }
 
 /*
@@ -1437,11 +1415,9 @@ void CtdlThreadSleep(int secs)
 {
        struct timespec wake_time;
        struct timeval time_now;
-       struct CtdlThreadNode *self;
        
        
-       self = CtdlThreadSelf();
-       if (!self)
+       if (!CT)
        {
                CtdlLogPrintf(CTDL_WARNING, "CtdlThreadSleep() called by something that is not a thread. Should we die?\n");
                return;
@@ -1452,19 +1428,13 @@ void CtdlThreadSleep(int secs)
        wake_time.tv_sec = time_now.tv_sec + secs;
        wake_time.tv_nsec = time_now.tv_usec * 10;
 
-//     begin_critical_section(S_THREAD_LIST);
-       ctdl_thread_internal_change_state (self, CTDL_THREAD_SLEEPING);
-//     end_critical_section(S_THREAD_LIST);
+       ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
        
-//     pthread_mutex_lock(&self->SleepMutex); /* Prevent something asking us to awaken before we've gone to sleep */
-       pthread_mutex_lock(&self->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
-       pthread_cond_timedwait(&self->SleepCond, &self->ThreadMutex, &wake_time);
-       pthread_mutex_unlock(&self->ThreadMutex);
-//     pthread_mutex_unlock(&self->SleepMutex);
+       pthread_mutex_lock(&CT->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
+       pthread_cond_timedwait(&CT->SleepCond, &CT->ThreadMutex, &wake_time);
+       pthread_mutex_unlock(&CT->ThreadMutex);
        
-//     begin_critical_section(S_THREAD_LIST);
-       ctdl_thread_internal_change_state (self, CTDL_THREAD_RUNNING);
-//     end_critical_section(S_THREAD_LIST);
+       ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 }
 
 
@@ -1473,22 +1443,19 @@ void CtdlThreadSleep(int secs)
  */
 static void ctdl_internal_thread_cleanup(void *arg)
 {
-       struct CtdlThreadNode *this_thread;
-       this_thread = CtdlThreadSelf();
        /*
         * In here we were called by the current thread because it is exiting
         * NB. WE ARE THE CURRENT THREAD
         */
-       CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (%ld) exited.\n", this_thread->name, this_thread->tid);
-//     begin_critical_section(S_THREAD_LIST);
+       CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (%ld) exited.\n", CT->name, CT->tid);
+       
        #ifdef HAVE_BACKTRACE
        eCrash_UnregisterThread();
        #endif
-       pthread_mutex_lock(&this_thread->ThreadMutex);
-       this_thread->state = CTDL_THREAD_EXITED;        // needs to be last thing else house keeping will unlink us too early
-       pthread_mutex_unlock(&this_thread->ThreadMutex);
-//     end_critical_section(S_THREAD_LIST);
-//     CtdlThreadGC();
+       
+       pthread_mutex_lock(&CT->ThreadMutex);
+       CT->state = CTDL_THREAD_EXITED; // needs to be last thing else house keeping will unlink us too early
+       pthread_mutex_unlock(&CT->ThreadMutex);
 }
 
 /*
@@ -1599,12 +1566,12 @@ void CtdlThreadGC (void)
                        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 == CtdlThreadList)
-                       CtdlThreadList = that_thread->next;
                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->next;
+                       that_thread->next->prev = that_thread->prev;
                
                pthread_mutex_unlock(&that_thread->ThreadMutex);
                pthread_cond_signal(&that_thread->ThreadCond);
@@ -1669,6 +1636,8 @@ static void *ctdl_internal_thread_func (void *arg)
        // Register the cleanup function to take care of when we exit.
        pthread_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
@@ -1677,7 +1646,7 @@ static void *ctdl_internal_thread_func (void *arg)
         */
        pthread_mutex_unlock(&this_thread->ThreadMutex);
                
-       if (!CtdlThreadCheckStop(this_thread))
+       if (!CtdlThreadCheckStop())
        {
                pthread_mutex_lock(&this_thread->ThreadMutex);
                this_thread->state = CTDL_THREAD_RUNNING;
@@ -1698,7 +1667,7 @@ static void *ctdl_internal_thread_func (void *arg)
        /*
         * run the thread to do the work but only if we haven't been asked to stop
         */
-       if (!CtdlThreadCheckStop(this_thread))
+       if (!CtdlThreadCheckStop())
                ret = (this_thread->thread_func)(this_thread->user_args);
        
        /*
@@ -1720,8 +1689,6 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
 {
        int ret = 0;
        struct CtdlThreadNode *this_thread;
-       int sigtrick = 0;
-       sigset_t old_signal_set;
 
        if (num_threads >= 32767)
        {
@@ -1802,20 +1769,6 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
         */
        this_thread->avg_blocked = 2;
        
-       /*
-        * We want to make sure that only the main thread handles signals,
-        * so that each signal is handled exactly once.  To do this, we
-        * make sure that each new thread has all the signals that we
-        * handle blocked.  To avoid race conditions, we block them in 
-        * the spawning thread first, then create the new thread (which
-        * inherits the settings), and then restore the old settings in
-        * the spawning thread.  This means that there is a brief period
-        * when no signals will be processed, but during that time they
-        * should be queued by the operating system.
-        */
-       if (pthread_equal(GC_thread, pthread_self())) 
-           sigtrick = ctdl_thread_internal_block_signals(&old_signal_set) == 0;
-
        /*
         * 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
@@ -1826,20 +1779,16 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
 
                CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
                        strerror(ret));
+               pthread_mutex_unlock(&this_thread->ThreadMutex);
                pthread_mutex_destroy(&(this_thread->ThreadMutex));
                pthread_cond_destroy(&(this_thread->ThreadCond));
                pthread_mutex_destroy(&(this_thread->SleepMutex));
                pthread_cond_destroy(&(this_thread->SleepCond));
                pthread_attr_destroy(&this_thread->attr);
                free(this_thread);
-               if (sigtrick)
-                       ctdl_thread_internal_restore_signals(&old_signal_set);
                return NULL;
        }
        
-       if (sigtrick)
-               ctdl_thread_internal_restore_signals(&old_signal_set);
-       
        num_threads++;  // Increase the count of threads in the system.
        if(this_thread->flags & CTDLTHREAD_WORKER)
                num_workers++;
@@ -1873,6 +1822,194 @@ struct CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_f
 
 
 
+/*
+ * Internal function to schedule a thread.
+ * Must be called from within a S_THREAD_LIST critical section
+ */ 
+struct CtdlThreadNode *CtdlThreadSchedule(char *name, long flags, void *(*thread_func) (void *arg), void *args, time_t when)
+{
+       int ret = 0;
+       struct CtdlThreadNode *this_thread;
+
+       if (num_threads >= 32767)
+       {
+               CtdlLogPrintf(CTDL_EMERG, "Thread system. Thread list full.\n");
+               return NULL;
+       }
+               
+       this_thread = malloc(sizeof(struct CtdlThreadNode));
+       if (this_thread == NULL) {
+               CtdlLogPrintf(CTDL_EMERG, "Thread system, can't allocate CtdlThreadNode, exiting\n");
+               return NULL;
+       }
+       // 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(struct CtdlThreadNode));
+       
+       /* Create the mutex's early so we can use them */
+       pthread_mutex_init (&(this_thread->ThreadMutex), NULL);
+       pthread_cond_init (&(this_thread->ThreadCond), NULL);
+       pthread_mutex_init (&(this_thread->SleepMutex), NULL);
+       pthread_cond_init (&(this_thread->SleepCond), NULL);
+       
+       this_thread->state = CTDL_THREAD_CREATE;
+       
+       if ((ret = pthread_attr_init(&this_thread->attr))) {
+               pthread_mutex_destroy(&(this_thread->ThreadMutex));
+               pthread_cond_destroy(&(this_thread->ThreadCond));
+               pthread_mutex_destroy(&(this_thread->SleepMutex));
+               pthread_cond_destroy(&(this_thread->SleepCond));
+               CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_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)
+       {
+               CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
+               if ((ret = pthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
+                       pthread_mutex_destroy(&(this_thread->ThreadMutex));
+                       pthread_cond_destroy(&(this_thread->ThreadCond));
+                       pthread_mutex_destroy(&(this_thread->SleepMutex));
+                       pthread_cond_destroy(&(this_thread->SleepCond));
+                       pthread_attr_destroy(&this_thread->attr);
+                       CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_setstacksize: %s\n",
+                               strerror(ret));
+                       free(this_thread);
+                       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;
+       /* 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;
+       
+       /*
+        * When to start this thread
+        */
+       this_thread->when = when;
+
+       begin_critical_section(S_SCHEDULE_LIST);
+       this_thread->next = CtdlThreadSchedList;
+       CtdlThreadSchedList = this_thread;
+       if (this_thread->next)
+               this_thread->next->prev = this_thread;
+       end_critical_section(S_SCHEDULE_LIST);
+       
+       return this_thread;
+}
+
+
+
+struct CtdlThreadNode *ctdl_thread_internal_start_scheduled (struct CtdlThreadNode *this_thread)
+{
+       int ret = 0;
+       
+       /*
+        * 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 = pthread_create(&this_thread->tid, &this_thread->attr, ctdl_internal_thread_func, this_thread) != 0))
+       {
+
+               CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
+                       strerror(ret));
+               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;
+       
+       return this_thread;
+}
+
+
+
+void ctdl_thread_internal_check_scheduled(void)
+{
+       struct CtdlThreadNode *this_thread, *that_thread;
+       time_t now;
+       
+       if (try_critical_section(S_SCHEDULE_LIST))
+               return; /* If this list is locked we wait till the next chance */
+       
+       now = time(NULL);
+       
+       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->next)
+                               that_thread->next->prev = that_thread->prev;
+                       if (that_thread->prev)
+                               that_thread->prev->next = that_thread->next;
+                       else
+                               CtdlThreadSchedList = that_thread->next;
+                       
+                       begin_critical_section(S_THREAD_LIST);
+                       if (CT->state > CTDL_THREAD_STOP_REQ)
+                       {       /* Only start it if the system is not stopping */
+                               pthread_mutex_lock(&that_thread->ThreadMutex);
+                               if (ctdl_thread_internal_start_scheduled (that_thread) == NULL)
+                               {
+                                       pthread_mutex_unlock(&that_thread->ThreadMutex);
+                                       pthread_mutex_destroy(&(that_thread->ThreadMutex));
+                                       pthread_cond_destroy(&(that_thread->ThreadCond));
+                                       pthread_mutex_destroy(&(that_thread->SleepMutex));
+                                       pthread_cond_destroy(&(that_thread->SleepCond));
+                                       pthread_attr_destroy(&that_thread->attr);
+                                       free(that_thread);
+                               }
+                               else
+                               {
+                                       CtdlLogPrintf(CTDL_INFO, "Thread system, Started a sceduled thread \"%s\".\n",
+                                               that_thread->name);
+                                       pthread_mutex_unlock(&that_thread->ThreadMutex);
+                                       ctdl_thread_internal_calc_loadavg();
+                               }
+                       }
+                       end_critical_section(S_THREAD_LIST);
+               }
+       }
+       end_critical_section(S_SCHEDULE_LIST);
+}
+
+
 /*
  * A warapper function for select so we can show a thread as blocked
  */
@@ -1990,11 +2127,8 @@ void *worker_thread(void *arg) {
        int force_purge = 0;
        int m;
        
-       CT_PUSH();
-       
-       cdb_allocate_tsd();
 
-       while (!CtdlThreadCheckStop(CT)) {
+       while (!CtdlThreadCheckStop()) {
 
                /* make doubly sure we're not holding any stale db handles
                 * which might cause a deadlock.
@@ -2040,13 +2174,13 @@ do_select:      force_purge = 0;
                        }
                }
 
-               if (!CtdlThreadCheckStop(CT)) {
+               if (!CtdlThreadCheckStop()) {
                        tv.tv_sec = 1;          /* wake up every second if no input */
                        tv.tv_usec = 0;
                        retval = CtdlThreadSelect(highest + 1, &readfds, NULL, NULL, &tv, CT);
                }
 
-               if (CtdlThreadCheckStop(CT)) return(NULL);
+               if (CtdlThreadCheckStop()) return(NULL);
 
                /* Now figure out who made this select() unblock.
                 * First, check for an error or exit condition.
@@ -2060,7 +2194,7 @@ do_select:        force_purge = 0;
                        if (errno != EINTR) {
                                CtdlLogPrintf(CTDL_EMERG, "Exiting (%s)\n", strerror(errno));
                                CtdlThreadStopAll();
-                       } else if (!CtdlThreadCheckStop(CT)) {
+                       } else if (!CtdlThreadCheckStop()) {
                                CtdlLogPrintf(CTDL_DEBUG, "Un handled select failure.\n");
                                goto do_select;
                        }