Moved all threading code into threads.c
[citadel.git] / citadel / sysdep.c
index a0ccfc8f10fb01e07d1c1550c84fb420ebf48cb8..fe372b76d337be8aa3f7b658876fd4d50effc037 100644 (file)
@@ -49,9 +49,6 @@
 #include <errno.h>
 #include <stdarg.h>
 #include <grp.h>
-#ifdef HAVE_PTHREAD_H
-#include <pthread.h>
-#endif
 #include <libcitadel.h>
 #include "citadel.h"
 #include "server.h"
@@ -73,6 +70,7 @@
 #endif
 
 #include "ctdl_module.h"
+#include "threads.h"
 
 #ifdef DEBUG_MEMORY_LEAKS
 struct igheap {
@@ -86,15 +84,12 @@ struct igheap *igheap = NULL;
 #endif
 
 
-pthread_mutex_t Critters[MAX_SEMAPHORES];      /* Things needing locking */
 pthread_key_t MyConKey;                                /* TSD key for MyContext() */
 
 int verbosity = DEFAULT_VERBOSITY;             /* Logging level */
 
 struct CitContext masterCC;
 time_t last_purge = 0;                         /* Last dead session purge */
-static int num_threads = 0;                    /* Current number of threads */
-static int num_workers = 0;                    /* Current number of worker threads */
 int num_sessions = 0;                          /* Current number of sessions */
 
 int syslog_facility = LOG_DAEMON;
@@ -193,19 +188,6 @@ static RETSIGTYPE signal_cleanup(int signum) {
 
 
 
-
-void InitialiseSemaphores(void)
-{
-       int i;
-
-       /* Set up a bunch of semaphores to be used for critical sections */
-       for (i=0; i<MAX_SEMAPHORES; ++i) {
-               pthread_mutex_init(&Critters[i], NULL);
-       }
-}
-
-
-
 /*
  * Some initialization stuff...
  */
@@ -271,59 +253,6 @@ void init_sysdep(void) {
 
 
 
-/*
- * Obtain a semaphore lock to begin a critical section.
- * but only if no one else has one
- */
-int try_critical_section(int 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.
-        */
-       if (    (which_one != S_FLOORCACHE)
-#ifdef DEBUG_MEMORY_LEAKS
-               && (which_one != S_DEBUGMEMLEAKS)
-#endif
-               && (which_one != S_RPLIST)
-       ) {
-               cdb_check_handles();
-       }
-       return (pthread_mutex_trylock(&Critters[which_one]));
-}
-
-
-/*
- * Obtain a semaphore lock to begin a critical section.
- */
-void begin_critical_section(int which_one)
-{
-       /* CtdlLogPrintf(CTDL_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.
-        */
-       if (    (which_one != S_FLOORCACHE)
-#ifdef DEBUG_MEMORY_LEAKS
-               && (which_one != S_DEBUGMEMLEAKS)
-#endif
-               && (which_one != S_RPLIST)
-       ) {
-               cdb_check_handles();
-       }
-       pthread_mutex_lock(&Critters[which_one]);
-}
-
-/*
- * Release a semaphore lock to end a critical section.
- */
-void end_critical_section(int which_one)
-{
-       pthread_mutex_unlock(&Critters[which_one]);
-}
-
-
 
 /*
  * This is a generic function to set up a master socket for listening on
@@ -1009,1063 +938,6 @@ int convert_login(char NameToConvert[]) {
        }
 }
 
-
-
-/*
- * New thread interface.
- * To create a thread you must call one of the create thread functions.
- * You must pass it the address of (a pointer to a CtdlThreadNode initialised to NULL) like this
- * struct CtdlThreadNode *node = NULL;
- * pass in &node
- * 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.
- * 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
- */
-
-
-struct CtdlThreadNode *CtdlThreadList = NULL;
-struct CtdlThreadNode *CtdlThreadSchedList = NULL;
-
-/*
- * Condition variable and Mutex for thread garbage collection
- */
-/*static pthread_mutex_t thread_gc_mutex = PTHREAD_MUTEX_INITIALIZER;
-static pthread_cond_t thread_gc_cond = PTHREAD_COND_INITIALIZER;
-*/
-static pthread_t GC_thread;
-static char *CtdlThreadStates[CTDL_THREAD_LAST_STATE];
-double CtdlThreadLoadAvg = 0;
-double CtdlThreadWorkerAvg = 0;
-pthread_key_t ThreadKey;
-
-/*
- * 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;
-       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)
-{
-       struct CtdlThreadNode *this_thread;
-       int ret = 0;
-       
-       GC_thread = pthread_self();
-       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(struct CtdlThreadNode));
-       if (this_thread == NULL) {
-               CtdlLogPrintf(CTDL_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(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;
-       
-       if ((ret = pthread_attr_init(&this_thread->attr))) {
-               CtdlLogPrintf(CTDL_EMERG, "Thread system, pthread_attr_init: %s\n", strerror(ret));
-               free(this_thread);
-               return;
-       }
-
-       this_thread->name = "Garbage Collection Thread";
-       
-       this_thread->tid = GC_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 update a threads load averages
- */
- void ctdl_thread_internal_update_avgs(struct CtdlThreadNode *this_thread)
- {
-       struct timeval now, result;
-       double last_duration;
-
-       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)
-               this_thread->avg_sleeping += last_duration;
-       if (this_thread->state == CTDL_THREAD_RUNNING)
-               this_thread->avg_running += last_duration;
-       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);
-}
-
-/*
- * A function to chenge the state of a thread
- */
-void ctdl_thread_internal_change_state (struct CtdlThreadNode *this_thread, enum CtdlThreadState new_state)
-{
-       /*
-        * Wether we change state or not we need update the load values
-        */
-       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))
-               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;
-       pthread_mutex_unlock(&this_thread->ThreadMutex);
-}
-
-
-/*
- * A function to tell all threads to exit
- */
-void CtdlThreadStopAll(void)
-{
-       //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
-       
-       struct CtdlThreadNode *this_thread;
-       
-       begin_critical_section(S_THREAD_LIST);
-       this_thread = CtdlThreadList;
-       while(this_thread)
-       {
-#ifdef THREADS_USESIGNALS
-               pthread_kill(this_thread->tid, SIGHUP);
-#endif
-               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);
-}
-
-
-/*
- * A function to wake up all sleeping threads
- */
-void CtdlThreadWakeAll(void)
-{
-       struct CtdlThreadNode *this_thread;
-       
-       CtdlLogPrintf(CTDL_DEBUG, "Thread system waking all threads.\n");
-       
-       begin_critical_section(S_THREAD_LIST);
-       this_thread = CtdlThreadList;
-       while(this_thread)
-       {
-               if (!this_thread->thread_func)
-               {
-                       pthread_cond_signal(&this_thread->ThreadCond);
-                       pthread_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 ret;
-       
-       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)
-       {
-               CtdlLogPrintf(CTDL_WARNING, "Thread system WARNING. Attempt to CtdlThreadRename() a non thread. %s\n", name);
-               return NULL;
-       }
-// FIXME: do we need this lock? I think not since the pointer asignmaent should be atomic
-       pthread_mutex_lock(&CT->ThreadMutex);
-       old_name = CT->name;
-       if (name)
-               CT->name = name;
-       pthread_mutex_unlock(&CT->ThreadMutex);
-       return (old_name);
-}      
-
-
-/*
- * A function to force a thread to exit
- */
-void CtdlThreadCancel(struct CtdlThreadNode *thread)
-{
-       struct CtdlThreadNode *this_thread;
-       
-       if (!thread)
-               this_thread = CT;
-       else
-               this_thread = thread;
-       if (!this_thread)
-       {
-               CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() a non thread.\n");
-               CtdlThreadStopAll();
-               return;
-       }
-       
-       if (!this_thread->thread_func)
-       {
-               CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC. Attempt to CtdlThreadCancel() the garbage collector.\n");
-               CtdlThreadStopAll();
-               return;
-       }
-       
-       ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_CANCELLED);
-       pthread_cancel(this_thread->tid);
-}
-
-
-
-/*
- * A function for a thread to check if it has been asked to stop
- */
-int CtdlThreadCheckStop(void)
-{
-       int state;
-       
-       if (!CT)
-       {
-               CtdlLogPrintf(CTDL_EMERG, "Thread system PANIC, CtdlThreadCheckStop() called by a non thread.\n");
-               CtdlThreadStopAll();
-               return -1;
-       }
-       
-       state = CT->state;
-
-#ifdef THREADS_USERSIGNALS
-       if (CT->signal)
-               CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" caught signal %d.\n", CT->name, CT->signal);
-#endif
-       pthread_mutex_lock(&CT->ThreadMutex);
-       if(state == CTDL_THREAD_STOP_REQ)
-       {
-               CT->state = CTDL_THREAD_STOPPING;
-               pthread_mutex_unlock(&CT->ThreadMutex);
-               return -1;
-       }
-       else if((state < CTDL_THREAD_STOP_REQ) && (state > CTDL_THREAD_CREATE))
-       {
-               pthread_mutex_unlock(&CT->ThreadMutex);
-               return -1;
-       }
-       pthread_mutex_unlock(&CT->ThreadMutex);
-       return 0;
-}
-
-
-/*
- * A function to ask a thread to exit
- * The thread must call CtdlThreadCheckStop() periodically to determine if it should exit
- */
-void CtdlThreadStop(struct CtdlThreadNode *thread)
-{
-       struct 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
-#ifdef THREADS_USESIGNALS
-       pthread_kill(this_thread->tid, SIGHUP); 
-#endif
-       ctdl_thread_internal_change_state (this_thread, CTDL_THREAD_STOP_REQ);
-       pthread_cond_signal(&this_thread->ThreadCond);
-       pthread_cond_signal(&this_thread->SleepCond);
-}
-
-/*
- * 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)
-       {
-               CtdlLogPrintf(CTDL_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);
-       
-       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);
-}
-
-
-/*
- * 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
-        */
-       CtdlLogPrintf(CTDL_NOTICE, "Thread \"%s\" (%ld) exited.\n", CT->name, CT->tid);
-       
-       #ifdef HAVE_BACKTRACE
-       eCrash_UnregisterThread();
-       #endif
-       
-       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);
-}
-
-/*
- * A quick function to show the load averages
- */
-void ctdl_thread_internal_calc_loadavg(void)
-{
-       struct CtdlThreadNode *that_thread;
-       double load_avg, worker_avg;
-       int workers = 0;
-
-       that_thread = CtdlThreadList;
-       load_avg = 0;
-       worker_avg = 0;
-       while(that_thread)
-       {
-               /* Update load averages */
-               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;
-               that_thread->avg_running /= 2;
-               that_thread->avg_blocked /= 2;
-               load_avg += that_thread->load_avg;
-               if (that_thread->flags & CTDLTHREAD_WORKER)
-               {
-                       worker_avg += that_thread->load_avg;
-                       workers++;
-               }
-#ifdef WITH_THREADLOG
-               CtdlLogPrintf(CTDL_DEBUG, "CtdlThread, \"%s\" (%ld) \"%s\" %f %f %f %f.\n",
-                       that_thread->name,
-                       that_thread->tid,
-                       CtdlThreadStates[that_thread->state],
-                       that_thread->avg_sleeping,
-                       that_thread->avg_running,
-                       that_thread->avg_blocked,
-                       that_thread->load_avg);
-#endif
-               pthread_mutex_unlock(&that_thread->ThreadMutex);
-               that_thread = that_thread->next;
-       }
-       CtdlThreadLoadAvg = load_avg/num_threads;
-       CtdlThreadWorkerAvg = worker_avg/workers;
-#ifdef WITH_THREADLOG
-       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
-}
-
-
-/*
- * Garbage collection routine.
- * Gets called by main() in a loop to clean up the thread list periodically.
- */
-void CtdlThreadGC (void)
-{
-       struct CtdlThreadNode *this_thread, *that_thread;
-       int workers = 0;
-       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
-       CtdlLogPrintf(CTDL_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;
-               
-               /* 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");
-                       abort();
-                       return;
-               }
-               
-               if (num_threads <= 0)
-               {       /* Sanity check */
-                       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");
-                       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;
-               
-               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
-                * We can join on the garbage collector thread the join should just return EDEADLCK
-                */
-               ret = pthread_join (that_thread->tid, NULL);
-               if (ret == EDEADLK)
-                       CtdlLogPrintf(CTDL_DEBUG, "Garbage collection on own thread.\n");
-               else if (ret == EINVAL)
-                       CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, that thread already joined on.\n");
-               else if (ret == ESRCH)
-                       CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, no thread to join on.\n");
-               else if (ret != 0)
-                       CtdlLogPrintf(CTDL_DEBUG, "Garbage collection, pthread_join returned an unknown error.\n");
-               /*
-                * Now we own that thread entry
-                */
-               CtdlLogPrintf(CTDL_INFO, "Garbage Collection for thread \"%s\" (%ld).\n", that_thread->name, that_thread->tid);
-               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);
-       }
-       
-       /* Sanity check number of worker threads */
-       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
-                       );
-               abort();
-       }
-       end_critical_section(S_THREAD_LIST);
-}
-
-
-
-/*
- * 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.
- */ 
-static void *ctdl_internal_thread_func (void *arg)
-{
-       struct 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 = (struct CtdlThreadNode *) arg;
-       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. */
-       /* 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);
-
-       
-       
-       /*
-        * 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
-        */
-       pthread_cleanup_pop(1); // Execute our cleanup routine and remove it
-       
-       return(ret);
-}
-
-
-/*
- * Internal function to create a thread.
- * Must be called from within a S_THREAD_LIST critical section
- */ 
-struct CtdlThreadNode *ctdl_internal_create_thread(char *name, long flags, void *(*thread_func) (void *arg), void *args)
-{
-       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);
-       
-       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;
-       }
-
-       /* 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
-               CtdlLogPrintf(CTDL_INFO, "Thread system. Creating BIG STACK thread.\n");
-#endif
-               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));
-                       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;
-       
-       /*
-        * 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));
-               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);
-               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;
-       
-       pthread_mutex_unlock(&this_thread->ThreadMutex);
-       
-       ctdl_thread_internal_calc_loadavg();
-       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
- */
-struct CtdlThreadNode *CtdlThreadCreate(char *name, long flags, void *(*thread_func) (void *arg), void *args)
-{
-       struct CtdlThreadNode *ret = NULL;
-       
-       begin_critical_section(S_THREAD_LIST);
-       ret = ctdl_internal_create_thread(name, flags, thread_func, args);
-       end_critical_section(S_THREAD_LIST);
-       return ret;
-}
-
-
-
-/*
- * 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);
-       
-#ifdef WITH_THREADLOG
-       CtdlLogPrintf(CTDL_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
-                       CtdlLogPrintf(CTDL_DEBUG, "About to start scheduled thread \"%s\".\n", that_thread->name);
-#endif
-                       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)
-                               {
-#ifdef WITH_THREADLOG
-                       CtdlLogPrintf(CTDL_DEBUG, "Failed to start scheduled thread \"%s\".\n", that_thread->name);
-#endif
-                                       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 scheduled thread \"%s\" (%ld).\n",
-                                               that_thread->name, that_thread->tid);
-                                       pthread_mutex_unlock(&that_thread->ThreadMutex);
-                                       ctdl_thread_internal_calc_loadavg();
-                               }
-                       }
-                       end_critical_section(S_THREAD_LIST);
-               }
-               else
-               {
-#ifdef WITH_THREADLOG
-                       CtdlLogPrintf(CTDL_DEBUG, "Thread \"%s\" will start in %ld seconds.\n", that_thread->name, that_thread->when - time(NULL));
-#endif
-               }
-       }
-       end_critical_section(S_SCHEDULE_LIST);
-}
-
-
-/*
- * 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, struct timeval *timeout)
-{
-       int ret;
-       
-       ctdl_thread_internal_change_state(CT, CTDL_THREAD_BLOCKED);
-       ret = select(n, readfds, writefds, exceptfds, timeout);
-       ctdl_thread_internal_change_state(CT, CTDL_THREAD_RUNNING);
-       return ret;
-}
-
 /*
  * Purge all sessions which have the 'kill_me' flag set.
  * This function has code to prevent it from running more than once every