]> code.citadel.org Git - citadel.git/blobdiff - citadel/sysdep.c
Prevent an ocassional segflt on exit.
[citadel.git] / citadel / sysdep.c
index 651912dde1f9a032bb4e928e422b216f67cc89da..cf12a75cddaf3d9f80b51d3a9b04e4bf1db966df 100644 (file)
@@ -1003,8 +1003,6 @@ int convert_login(char NameToConvert[]) {
  * If the thread is created *node will point to the thread control structure for the created thread.
  * If the thread creation fails *node remains NULL
  * Do not free the memory pointed to by *node, it doesn't belong to you.
- * If your thread function returns it will be started again without creating a new thread.
- * If your thread function wants to exit it should call CtdlThreadExit(ret_code);
  * This new interface duplicates much of the eCrash stuff. We should go for closer integration since that would
  * remove the need for the calls to eCrashRegisterThread and friends
  */
@@ -1022,6 +1020,8 @@ 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
  */
@@ -1078,6 +1078,64 @@ static void ctdl_thread_internal_restore_signals(sigset_t *old_set)
 }
 
 
+
+/*
+ * 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 = 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)
+{
+       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);
+}
+
+
+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;
@@ -1086,6 +1144,7 @@ void ctdl_thread_internal_cleanup(void)
        {
                free (CtdlThreadStates[i]);
        }
+       ctdl_thread_internal_free_tsd();
 }
 
 void ctdl_thread_internal_init(void)
@@ -1114,6 +1173,11 @@ void ctdl_thread_internal_init(void)
        // 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));
        
+       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);
+       
        /* We are garbage collector so create us as running */
        this_thread->state = CTDL_THREAD_RUNNING;
        
@@ -1123,12 +1187,10 @@ void ctdl_thread_internal_init(void)
                return;
        }
 
-       this_thread->name = strdup("Garbage Collection Thread");
-       
-       pthread_mutex_init (&(this_thread->ThreadMutex), NULL);
-       pthread_cond_init (&(this_thread->ThreadCond), NULL);
+       this_thread->name = "Garbage Collection Thread";
        
        this_thread->tid = GC_thread;
+       CT = this_thread;
        
        num_threads++;  // Increase the count of threads in the system.
 
@@ -1152,6 +1214,7 @@ void ctdl_thread_internal_init(void)
 
        gettimeofday(&now, NULL);
        timersub(&now, &(this_thread->last_state_change), &result);
+       pthread_mutex_lock(&this_thread->ThreadMutex);
        // result now has a timeval for the time we spent in the last state since we last updated
        last_duration = (double)result.tv_sec + ((double)result.tv_usec / (double) 1000000);
        if (this_thread->state == CTDL_THREAD_SLEEPING)
@@ -1161,6 +1224,7 @@ void ctdl_thread_internal_init(void)
        if (this_thread->state == CTDL_THREAD_BLOCKED)
                this_thread->avg_blocked += last_duration;
        memcpy (&this_thread->last_state_change, &now, sizeof (struct timeval));
+       pthread_mutex_unlock(&this_thread->ThreadMutex);
 }
 
 /*
@@ -1171,8 +1235,8 @@ void ctdl_thread_internal_change_state (struct CtdlThreadNode *this_thread, enum
        /*
         * Wether we change state or not we need update the load values
         */
-       pthread_mutex_lock(&this_thread->ThreadMutex); /* To prevent race condition of a sleeping thread */
        ctdl_thread_internal_update_avgs(this_thread);
+       pthread_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))
@@ -1197,14 +1261,10 @@ 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_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);
@@ -1212,13 +1272,13 @@ void CtdlThreadStopAll(void)
 
 
 /*
- * A function to signal that we need to do garbage collection on the thread list
+ * A function to wake up all sleeping threads
  */
-void CtdlThreadGC(void)
+void CtdlThreadWakeAll(void)
 {
        struct CtdlThreadNode *this_thread;
        
-       CtdlLogPrintf(CTDL_DEBUG, "Thread system signalling garbage collection.\n");
+       CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
        
        begin_critical_section(S_THREAD_LIST);
        this_thread = CtdlThreadList;
@@ -1226,9 +1286,8 @@ void CtdlThreadGC(void)
        {
                if (!this_thread->thread_func)
                {
-//                     pthread_mutex_lock(&this_thread->ThreadMutex);
                        pthread_cond_signal(&this_thread->ThreadCond);
-//                     pthread_mutex_unlock(&this_thread->ThreadMutex);
+                       pthread_cond_signal(&this_thread->SleepCond);
                }
                this_thread = this_thread->next;
        }
@@ -1241,32 +1300,42 @@ void CtdlThreadGC(void)
  */
 int CtdlThreadGetCount(void)
 {
-       return num_threads;
+       int ret;
+       
+       begin_critical_section(S_THREAD_LIST);
+       ret = num_threads;
+       end_critical_section(S_THREAD_LIST);
+       return ret;
 }
 
-/*
- * A function to find the thread structure for this thread
- */
-struct CtdlThreadNode *CtdlThreadSelf(void)
+int CtdlThreadGetWorkers(void)
 {
-       pthread_t self_tid;
-       struct CtdlThreadNode *this_thread;
+       int ret;
        
-       self_tid = pthread_self();
+       begin_critical_section(S_THREAD_LIST);
+       ret =  num_workers;
+       end_critical_section(S_THREAD_LIST);
+       return ret;
+}
+
+double CtdlThreadGetWorkerAvg(void)
+{
+       double ret;
        
        begin_critical_section(S_THREAD_LIST);
-       this_thread = CtdlThreadList;
-       while(this_thread)
-       {
-               if (pthread_equal(self_tid, this_thread->tid))
-               {
-                       end_critical_section(S_THREAD_LIST);
-                       return this_thread;
-               }
-               this_thread = this_thread->next;
-       }
+       ret =  CtdlThreadWorkerAvg;
        end_critical_section(S_THREAD_LIST);
-       return NULL;
+       return ret;
+}
+
+double CtdlThreadGetLoadAvg(void)
+{
+       double ret;
+       
+       begin_critical_section(S_THREAD_LIST);
+       ret =  CtdlThreadLoadAvg;
+       end_critical_section(S_THREAD_LIST);
+       return ret;
 }
 
 
@@ -1274,29 +1343,22 @@ struct CtdlThreadNode *CtdlThreadSelf(void)
 
 /*
  * A function to rename a thread
- * Returns a char * and the caller owns the memory and should free it
+ * Returns a const char *
  */
-char *CtdlThreadName(struct CtdlThreadNode *thread, char *name)
+const char *CtdlThreadName(const char *name)
 {
-       struct CtdlThreadNode *this_thread;
-       char *old_name;
+       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.\n");
+               CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
                return NULL;
        }
-       begin_critical_section(S_THREAD_LIST);
-       old_name = this_thread->name;
+       pthread_mutex_lock(&CT->ThreadMutex);
+       old_name = CT->name;
        if (name)
-               this_thread->name = strdup (name);
-       else
-               old_name = strdup(old_name);
-       end_critical_section (S_THREAD_LIST);
+               CT->name = name;
+       pthread_mutex_unlock(&CT->ThreadMutex);
        return (old_name);
 }      
 
@@ -1309,7 +1371,7 @@ void CtdlThreadCancel(struct CtdlThreadNode *thread)
        struct CtdlThreadNode *this_thread;
        
        if (!thread)
-               this_thread = CtdlThreadSelf();
+               this_thread = CT;
        else
                this_thread = thread;
        if (!this_thread)
@@ -1326,10 +1388,8 @@ 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);
 }
 
 
@@ -1339,23 +1399,25 @@ void CtdlThreadCancel(struct CtdlThreadNode *thread)
  */
 int CtdlThreadCheckStop(void)
 {
-       struct CtdlThreadNode *this_thread;
-       
-       this_thread = CtdlThreadSelf();
-       if (!this_thread)
+       if (!CT)
        {
                CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
                CtdlThreadStopAll();
                return -1;
        }
-       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;
+               CT->state = CTDL_THREAD_STOPPING;
+               pthread_mutex_unlock(&CT->ThreadMutex);
                return -1;
        }
-       else if(this_thread->state < CTDL_THREAD_STOP_REQ)
+       else if((CT->state < CTDL_THREAD_STOP_REQ) && (CT->state > CTDL_THREAD_CREATE))
+       {
+               pthread_mutex_unlock(&CT->ThreadMutex);
                return -1;
-               
+       }
+       pthread_mutex_unlock(&CT->ThreadMutex);
        return 0;
 }
 
@@ -1369,7 +1431,7 @@ void CtdlThreadStop(struct CtdlThreadNode *thread)
        struct CtdlThreadNode *this_thread;
        
        if (!thread)
-               this_thread = CtdlThreadSelf();
+               this_thread = CT;
        else
                this_thread = thread;
        if (!this_thread)
@@ -1377,12 +1439,9 @@ 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_mutex_unlock(&this_thread->ThreadMutex);
-       end_critical_section(S_THREAD_LIST);
+       pthread_cond_signal(&this_thread->SleepCond);
 }
 
 /*
@@ -1392,30 +1451,26 @@ 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;
        }
        
-       begin_critical_section(S_THREAD_LIST);
-       ctdl_thread_internal_change_state (self, CTDL_THREAD_SLEEPING);
-       pthread_mutex_lock(&self->ThreadMutex); /* Prevent something asking us to awaken before we've gone to sleep */
-       end_critical_section(S_THREAD_LIST);
-       
        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;
-       pthread_cond_timedwait(&self->ThreadCond, &self->ThreadMutex, &wake_time);
-       begin_critical_section(S_THREAD_LIST);
-       pthread_mutex_unlock(&self->ThreadMutex);
-       ctdl_thread_internal_change_state (self, CTDL_THREAD_RUNNING);
-       end_critical_section(S_THREAD_LIST);
+
+       ctdl_thread_internal_change_state (CT, CTDL_THREAD_SLEEPING);
+       
+       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);
+       
+       ctdl_thread_internal_change_state (CT, CTDL_THREAD_RUNNING);
 }
 
 
@@ -1424,20 +1479,19 @@ 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
-       this_thread->state = CTDL_THREAD_EXITED;        // needs to be last thing else house keeping will unlink us too early
-       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);
 }
 
 /*
@@ -1449,15 +1503,14 @@ void ctdl_thread_internal_calc_loadavg(void)
        double load_avg, worker_avg;
        int workers = 0;
 
-       begin_critical_section(S_THREAD_LIST);
        that_thread = CtdlThreadList;
        load_avg = 0;
        worker_avg = 0;
        while(that_thread)
        {
                /* Update load averages */
-               pthread_mutex_lock(&that_thread->ThreadMutex);
                ctdl_thread_internal_update_avgs(that_thread);
+               pthread_mutex_lock(&that_thread->ThreadMutex);
                that_thread->load_avg = that_thread->avg_sleeping + that_thread->avg_running + that_thread->avg_blocked;
                that_thread->load_avg = that_thread->avg_running / that_thread->load_avg * 100;
                that_thread->avg_sleeping /= 2;
@@ -1485,9 +1538,8 @@ void ctdl_thread_internal_calc_loadavg(void)
        CtdlThreadLoadAvg = load_avg/num_threads;
        CtdlThreadWorkerAvg = worker_avg/workers;
 #ifdef WITH_THREADLOG
-       CtdlLogPrintf(CTDL_INFO, "System load average %f, workers averag %f\n", CtdlThreadLoadAvg, CtdlThreadWorkerAvg);
+       CtdlLogPrintf(CTDL_INFO, "System load average %f, workers averag %f, threads %d, workers %d, sessions %d\n", CtdlThreadLoadAvg, CtdlThreadWorkerAvg, num_threads, num_workers, num_sessions);
 #endif
-       end_critical_section(S_THREAD_LIST);
 }
 
 
@@ -1495,11 +1547,13 @@ void ctdl_thread_internal_calc_loadavg(void)
  * Garbage collection routine.
  * Gets called by main() in a loop to clean up the thread list periodically.
  */
-void ctdl_internal_thread_gc (void)
+void CtdlThreadGC (void)
 {
        struct CtdlThreadNode *this_thread, *that_thread;
        int workers = 0;
        
+       begin_critical_section(S_THREAD_LIST);
+       
        /* Handle exiting of garbage collector thread */
        if(num_threads == 1)
                CtdlThreadList->state = CTDL_THREAD_EXITED;
@@ -1510,7 +1564,6 @@ void ctdl_internal_thread_gc (void)
        /*
         * Woke up to do garbage collection
         */
-       begin_critical_section(S_THREAD_LIST);
        this_thread = CtdlThreadList;
        while(this_thread)
        {
@@ -1518,29 +1571,36 @@ void ctdl_internal_thread_gc (void)
                this_thread = this_thread->next;
                
                /* Do we need to clean up this thread? */
+               pthread_mutex_lock(&that_thread->ThreadMutex);
                if (that_thread->state != CTDL_THREAD_EXITED)
                {
                        if(that_thread->flags & CTDLTHREAD_WORKER)
                                workers++;      /* Sanity check on number of worker threads */
+                       pthread_mutex_unlock(&that_thread->ThreadMutex);
                        continue;
                }
                
                if (pthread_equal(that_thread->tid, pthread_self()) && that_thread->thread_func)
                {       /* Sanity check */
+                       pthread_mutex_unlock(&that_thread->ThreadMutex);
                        end_critical_section(S_THREAD_LIST);
                        CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, a thread is trying to clean up after itself.\n");
-                       CtdlThreadStopAll();
+                       abort();
                        return;
                }
                
                if (num_threads <= 0)
                {       /* Sanity check */
-                       end_critical_section (S_THREAD_LIST);
+                       pthread_mutex_unlock(&that_thread->ThreadMutex);
+                       end_critical_section(S_THREAD_LIST);
                        CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, num_threads <= 0 and trying to do Garbage Collection.\n");
-                       CtdlThreadStopAll();
+                       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 == CtdlThreadList)
                        CtdlThreadList = that_thread->next;
@@ -1548,10 +1608,12 @@ void ctdl_internal_thread_gc (void)
                        that_thread->prev->next = that_thread->next;
                if(that_thread->next)
                        that_thread->next->prev = that_thread->next;
-               num_threads--;
-               if(that_thread->flags & CTDLTHREAD_WORKER)
-                       num_workers--;  /* This is a wroker thread so reduce the count. */
                
+               pthread_mutex_unlock(&that_thread->ThreadMutex);
+               pthread_cond_signal(&that_thread->ThreadCond);
+               pthread_cond_signal(&that_thread->SleepCond);   // Make sure this thread is awake
+               pthread_mutex_lock(&that_thread->ThreadMutex);  // Make sure it has done what its doing
+               pthread_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
@@ -1564,10 +1626,10 @@ void ctdl_internal_thread_gc (void)
                 * Now we own that thread entry
                 */
                CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (%ld).\n", that_thread->name, that_thread->tid);
-               if(that_thread->name)
-                       free(that_thread->name);
                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);
        }
@@ -1576,8 +1638,11 @@ void ctdl_internal_thread_gc (void)
        if (workers != num_workers)
        {
                end_critical_section(S_THREAD_LIST);
-               CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n", workers, num_workers);
-               return;
+               CtdlLogPrintf(CTDL_EMERG,
+                       "Thread system PANIC, discrepancy in number of worker threads. Counted %d, should be %d.\n",
+                       workers, num_workers
+                       );
+               abort();
        }
        end_critical_section(S_THREAD_LIST);
 }
@@ -1600,25 +1665,46 @@ static void *ctdl_internal_thread_func (void *arg)
         * can continue its execution.
         */
        begin_critical_section(S_THREAD_LIST);
-       // Get our thread data structure
        this_thread = (struct CtdlThreadNode *) arg;
-       this_thread->state = CTDL_THREAD_RUNNING;
-       this_thread->pid = getpid();
        gettimeofday(&this_thread->start_time, NULL);           /* Time this thread started */
+       pthread_mutex_lock(&this_thread->ThreadMutex);
+       
+       // 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. */
-       end_critical_section(S_THREAD_LIST);
+       /* 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.
+        */
+       pthread_mutex_unlock(&this_thread->ThreadMutex);
                
+       if (!CtdlThreadCheckStop())
+       {
+               pthread_mutex_lock(&this_thread->ThreadMutex);
+               this_thread->state = CTDL_THREAD_RUNNING;
+               pthread_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
        CtdlLogPrintf(CTDL_NOTICE, "Created a new thread \"%s\" (%ld). \n", this_thread->name, this_thread->tid);
 
-       // Register the cleanup function to take care of when we exit.
-       pthread_cleanup_push(ctdl_internal_thread_cleanup, NULL);
        
        
        /*
-        * run the thread to do the work
+        * run the thread to do the work but only if we haven't been asked to stop
         */
-       ret = (this_thread->thread_func)(this_thread->user_args);
+       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
@@ -1656,9 +1742,22 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
        // 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);
+       
+       pthread_mutex_lock(&this_thread->ThreadMutex);
+       
        this_thread->state = CTDL_THREAD_CREATE;
        
        if ((ret = pthread_attr_init(&this_thread->attr))) {
+               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));
                CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_init: %s\n", strerror(ret));
                free(this_thread);
                return NULL;
@@ -1672,9 +1771,14 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
        {
                CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
                if ((ret = pthread_attr_setstacksize(&this_thread->attr, THREADSTACKSIZE))) {
+                       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);
                        CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_setstacksize: %s\n",
                                strerror(ret));
-                       pthread_attr_destroy(&this_thread->attr);
                        free(this_thread);
                        return NULL;
                }
@@ -1687,18 +1791,21 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
         */
        if(name)
        {
-               this_thread->name = strdup(name);
+               this_thread->name = name;
        }
        else
        {
-               this_thread->name = strdup("Un-named Thread");
+               this_thread->name = "Un-named Thread";
        }
        
        this_thread->flags = flags;
        this_thread->thread_func = thread_func;
        this_thread->user_args = args;
-       pthread_mutex_init (&(this_thread->ThreadMutex), NULL);
-       pthread_cond_init (&(this_thread->ThreadCond), NULL);
+       /* 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;
        
        /*
         * We want to make sure that only the main thread handles signals,
@@ -1711,8 +1818,8 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
         * 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;
+//     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
@@ -1724,19 +1831,19 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
 
                CtdlLogPrintf(CTDL_ALERT, "Thread system, Can't create thread: %s\n",
                        strerror(ret));
-               if (this_thread->name)
-                       free (this_thread->name);
                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);
+//             if (sigtrick)
+//                     ctdl_thread_internal_restore_signals(&old_signal_set);
                return NULL;
        }
        
-       if (sigtrick)
-               ctdl_thread_internal_restore_signals(&old_signal_set);
+//     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)
@@ -1746,10 +1853,10 @@ struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void
        CtdlThreadList = this_thread;
        if (this_thread->next)
                this_thread->next->prev = this_thread;
-       // Register for tracing
-       #ifdef HAVE_BACKTRACE
-       eCrash_RegisterThread(this_thread->name, 0);
-       #endif
+       
+       pthread_mutex_unlock(&this_thread->ThreadMutex);
+       
+       ctdl_thread_internal_calc_loadavg();
        return this_thread;
 }
 
@@ -1774,12 +1881,10 @@ struct CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_f
 /*
  * A warapper function for select so we can show a thread as blocked
  */
-int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, const struct timeval *timeout)
+int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout, struct CtdlThreadNode *self)
 {
-       struct CtdlThreadNode *self;
        int ret;
        
-       self = CtdlThreadSelf();
        ctdl_thread_internal_change_state(self, CTDL_THREAD_BLOCKED);
        ret = select(n, readfds, writefds, exceptfds, timeout);
        ctdl_thread_internal_change_state(self, CTDL_THREAD_RUNNING);
@@ -1792,26 +1897,21 @@ int CtdlThreadSelect(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds
  * few seconds, because running it after every single unbind would waste a lot
  * of CPU time and keep the context list locked too much.  To force it to run
  * anyway, set "force" to nonzero.
- *
- *
- * After that's done, we raise the size of the worker thread pool
- * if such an action is appropriate.
  */
 void dead_session_purge(int force) {
        struct CitContext *ptr, *ptr2;          /* general-purpose utility pointer */
        struct CitContext *rem = NULL;  /* list of sessions to be destroyed */
        
-       CtdlThreadPushName("dead_session_purge");
-       
        if (force == 0) {
                if ( (time(NULL) - last_purge) < 5 ) {
-                       CtdlThreadPopName();
                        return; /* Too soon, go away */
                }
        }
        time(&last_purge);
 
-       begin_critical_section(S_SESSION_TABLE);
+       if (try_critical_section(S_SESSION_TABLE))
+               return;
+               
        ptr = ContextList;
        while (ptr) {
                ptr2 = ptr;
@@ -1830,11 +1930,9 @@ void dead_session_purge(int force) {
                        }
 
                        --num_sessions;
-
                        /* And put it on our to-be-destroyed list */
                        ptr2->next = rem;
                        rem = ptr2;
-
                }
        }
        end_critical_section(S_SESSION_TABLE);
@@ -1850,18 +1948,6 @@ void dead_session_purge(int force) {
                rem = rem->next;
                free(ptr);
        }
-
-       /* Raise the size of the worker thread pool if necessary. */
-       begin_critical_section(S_THREAD_LIST);
-       if ( (num_sessions > num_workers)
-          && (num_workers < config.c_max_workers) ) {
-               ctdl_internal_create_thread("Worker Thread", CTDLTHREAD_BIGSTACK + CTDLTHREAD_WORKER, worker_thread, NULL);
-       }
-       end_critical_section(S_THREAD_LIST);
-       // FIXME: reduce the number of worker threads too
-       
-       CtdlThreadPopName();
-       
 }
 
 
@@ -1908,8 +1994,7 @@ void *worker_thread(void *arg) {
        struct timeval tv;
        int force_purge = 0;
        int m;
-
-       cdb_allocate_tsd();
+       
 
        while (!CtdlThreadCheckStop()) {
 
@@ -1960,8 +2045,7 @@ do_select:        force_purge = 0;
                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);
-//                     retval = select(highest + 1, &readfds, NULL, NULL, &tv);
+                       retval = CtdlThreadSelect(highest + 1, &readfds, NULL, NULL, &tv, CT);
                }
 
                if (CtdlThreadCheckStop()) return(NULL);
@@ -2091,7 +2175,6 @@ SKIP_SELECT:
 
                dead_session_purge(force_purge);
                do_housekeeping();
-               check_sched_shutdown();
        }
        /* If control reaches this point, the server is shutting down */        
        return(NULL);