Porting Toolkit to Symbian. It should work while some sporadic
[silc.git] / lib / silcutil / silcschedule.c
index 260ed50de0994be6f8cd53c3a31de8b9fafb35c5..6d3f09e1c3d3794f4776ea5211a4115c1492494c 100644 (file)
@@ -4,13 +4,12 @@
 
   Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 1998 - 2001 Pekka Riikonen
+  Copyright (C) 1998 - 2007 Pekka Riikonen
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
-  the Free Software Foundation; either version 2 of the License, or
-  (at your option) any later version.
-  
+  the Free Software Foundation; version 2 of the License.
+
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 
 */
 /* $Id$ */
-/* XXX on multi-threads the task queue locking is missing here. */
 
-#include "silcincludes.h"
+#include "silc.h"
 
-/* Routine to remove the task. Implemented in silctask.c. */
-int silc_task_remove(SilcTaskQueue queue, SilcTask task);
+/************************** Types and definitions ***************************/
 
-/* System specific routines. Implemented under unix/ and win32/. */
+/* Platform specific implementation */
+extern const SilcScheduleOps schedule_ops;
 
-/* System specific select(). */
-int silc_select(int n, fd_set *readfds, fd_set *writefds,
-               fd_set *exceptfds, struct timeval *timeout);
+static void silc_schedule_task_remove(SilcSchedule schedule, SilcTask task);
+static void silc_schedule_dispatch_fd(SilcSchedule schedule);
+static void silc_schedule_dispatch_timeout(SilcSchedule schedule,
+                                          SilcBool dispatch_all);
 
-/* Initializes the wakeup of the scheduler. In multi-threaded environment
-   the scheduler needs to be wakenup when tasks are added or removed from
-   the task queues. This will initialize the wakeup for the scheduler.
-   Any tasks that needs to be registered must be registered to the `queue'.
-   It is guaranteed that the scheduler will automatically free any
-   registered tasks in this queue. This is system specific routine. */
-void *silc_schedule_wakeup_init(void *queue);
 
-/* Uninitializes the system specific wakeup. */
-void silc_schedule_wakeup_uninit(void *context);
+/************************ Static utility functions **************************/
 
-/* Wakes up the scheduler. This is platform specific routine */
-void silc_schedule_wakeup_internal(void *context);
+/* Fd task hash table destructor */
 
-/* Structure holding list of file descriptors, scheduler is supposed to
-   be listenning. The max_fd field is the maximum number of possible file
-   descriptors in the list. This value is set at the initialization
-   of the scheduler and it usually is the maximum number of connections 
-   allowed. */
-typedef struct {
-  int *fd;
-  uint32 last_fd;
-  uint32 max_fd;
-} SilcScheduleFdList;
+static void silc_schedule_fd_destructor(void *key, void *context,
+                                       void *user_context)
+{
+  silc_free(context);
+}
 
-/* 
-   SILC Scheduler structure.
+/* Executes file descriptor tasks. Invalid tasks are removed here. */
 
-   This is the actual schedule object in SILC. Both SILC client and server 
-   uses this same scheduler. Actually, this scheduler could be used by any
-   program needing scheduling.
+static void silc_schedule_dispatch_fd(SilcSchedule schedule)
+{
+  SilcTaskFd task;
+  SilcTask t;
+
+  /* The dispatch list includes only valid tasks, and tasks that have
+     something to dispatch.  Dispatching is atomic; no matter if another
+     thread invalidates a task when we unlock, we dispatch to completion. */
+  SILC_SCHEDULE_UNLOCK(schedule);
+  silc_list_start(schedule->fd_dispatch);
+  while ((task = silc_list_get(schedule->fd_dispatch))) {
+    t = (SilcTask)task;
+
+    /* Is the task ready for reading */
+    if (task->revents & SILC_TASK_READ)
+      t->callback(schedule, schedule->app_context, SILC_TASK_READ,
+                 task->fd, t->context);
+
+    /* Is the task ready for writing */
+    if (t->valid && task->revents & SILC_TASK_WRITE)
+      t->callback(schedule, schedule->app_context, SILC_TASK_WRITE,
+                 task->fd, t->context);
+  }
+  SILC_SCHEDULE_LOCK(schedule);
 
-   Following short description of the fields:
+  /* Remove invalidated tasks */
+  silc_list_start(schedule->fd_dispatch);
+  while ((task = silc_list_get(schedule->fd_dispatch)))
+    if (silc_unlikely(!task->header.valid))
+      silc_schedule_task_remove(schedule, (SilcTask)task);
+}
+
+/* Executes all tasks whose timeout has expired. The task is removed from
+   the task queue after the callback function has returned. Also, invalid
+   tasks are removed here. */
+
+static void silc_schedule_dispatch_timeout(SilcSchedule schedule,
+                                          SilcBool dispatch_all)
+{
+  SilcTask t;
+  SilcTaskTimeout task;
+  struct timeval curtime;
+  int count = 0;
 
-   SilcTaskQueue fd_queue
+  SILC_LOG_DEBUG(("Running timeout tasks"));
 
-       Task queue hook for non-timeout tasks. Usually this means that these
-       tasks perform different kind of I/O on file descriptors. File 
-       descriptors are usually network sockets but they actually can be
-       any file descriptors. This hook is initialized in silc_schedule_init
-       function. Timeout tasks should not be added to this queue because
-       they will never expire.
+  silc_gettimeofday(&curtime);
 
-   SilcTaskQueue timeout_queue
+  /* First task in the task queue has always the earliest timeout. */
+  silc_list_start(schedule->timeout_queue);
+  task = silc_list_get(schedule->timeout_queue);
+  if (silc_unlikely(!task))
+    return;
+  do {
+    t = (SilcTask)task;
 
-       Task queue hook for timeout tasks. This hook is reserved specificly
-       for tasks with timeout. Non-timeout tasks should not be added to this
-       queue because they will never get scheduled. This hook is also
-       initialized in silc_schedule_init function.
+    /* Remove invalid task */
+    if (silc_unlikely(!t->valid)) {
+      silc_schedule_task_remove(schedule, t);
+      continue;
+    }
 
-   SilcTaskQueue generic_queue
+    /* Execute the task if the timeout has expired */
+    if (silc_compare_timeval(&task->timeout, &curtime) > 0 && !dispatch_all)
+      break;
 
-       Task queue hook for generic tasks. This hook is reserved specificly
-       for generic tasks, tasks that apply to all file descriptors, except
-       to those that have specificly registered a non-timeout task. This hook
-       is also initialized in silc_schedule_init function.
+    t->valid = FALSE;
+    SILC_SCHEDULE_UNLOCK(schedule);
+    t->callback(schedule, schedule->app_context, SILC_TASK_EXPIRE, 0,
+               t->context);
+    SILC_SCHEDULE_LOCK(schedule);
 
-   SilcScheduleFdList fd_list
+    /* Remove the expired task */
+    silc_schedule_task_remove(schedule, t);
 
-       List of file descriptors the scheduler is supposed to be listenning.
-       This is updated internally.
+    /* Balance when we have lots of small timeouts */
+    if (silc_unlikely((++count) > 40))
+      break;
+  } while (silc_likely((task = silc_list_get(schedule->timeout_queue))));
+}
 
-   struct timeval *timeout;
+/* Calculates next timeout. This is the timeout value when at earliest some
+   of the timeout tasks expire. If this is in the past, they will be
+   dispatched now. */
 
-       Pointer to the schedules next timeout. Value of this timeout is
-       automatically updated in the silc_schedule function.
+static void silc_schedule_select_timeout(SilcSchedule schedule)
+{
+  SilcTask t;
+  SilcTaskTimeout task;
+  struct timeval curtime;
+  SilcBool dispatch = TRUE;
 
-   int valid
+  /* Get the current time */
+  silc_gettimeofday(&curtime);
+  schedule->has_timeout = FALSE;
 
-       Marks validity of the scheduler. This is a boolean value. When this
-       is false the scheduler is terminated and the program will end. This
-       set to true when the scheduler is initialized with silc_schedule_init
-       function.
+  /* First task in the task queue has always the earliest timeout. */
+  silc_list_start(schedule->timeout_queue);
+  task = silc_list_get(schedule->timeout_queue);
+  if (silc_unlikely(!task))
+    return;
+  do {
+    t = (SilcTask)task;
+
+    /* Remove invalid task */
+    if (silc_unlikely(!t->valid)) {
+      silc_schedule_task_remove(schedule, t);
+      continue;
+    }
+
+    /* If the timeout is in past, we will run the task and all other
+       timeout tasks from the past. */
+    if (silc_compare_timeval(&task->timeout, &curtime) <= 0 && dispatch) {
+      silc_schedule_dispatch_timeout(schedule, FALSE);
+      if (silc_unlikely(!schedule->valid))
+       return;
+
+      /* Start selecting new timeout again after dispatch */
+      silc_list_start(schedule->timeout_queue);
+      dispatch = FALSE;
+      continue;
+    }
+
+    /* Calculate the next timeout */
+    curtime.tv_sec = task->timeout.tv_sec - curtime.tv_sec;
+    curtime.tv_usec = task->timeout.tv_usec - curtime.tv_usec;
+    if (curtime.tv_sec < 0)
+      curtime.tv_sec = 0;
+
+    /* We wouldn't want to go under zero, check for it. */
+    if (curtime.tv_usec < 0) {
+      curtime.tv_sec -= 1;
+      if (curtime.tv_sec < 0)
+       curtime.tv_sec = 0;
+      curtime.tv_usec += 1000000L;
+    }
+    break;
+  } while ((task = silc_list_get(schedule->timeout_queue)));
+
+  /* Save the timeout */
+  if (task) {
+    schedule->timeout = curtime;
+    schedule->has_timeout = TRUE;
+    SILC_LOG_DEBUG(("timeout: sec=%d, usec=%d", schedule->timeout.tv_sec,
+                   schedule->timeout.tv_usec));
+  }
+}
 
-   fd_set in
-   fd_set out
+/* Removes task from the scheduler.  This must be called with scheduler
+   locked. */
 
-       File descriptor sets for select(). These are automatically managed
-       by the scheduler and should not be touched otherwise.
+static void silc_schedule_task_remove(SilcSchedule schedule, SilcTask task)
+{
+  SilcTaskFd ftask;
+
+  if (silc_unlikely(task == SILC_ALL_TASKS)) {
+    SilcTask task;
+    SilcHashTableList htl;
+    SilcUInt32 fd;
+
+    /* Delete from fd queue */
+    silc_hash_table_list(schedule->fd_queue, &htl);
+    while (silc_hash_table_get(&htl, (void *)&fd, (void *)&task))
+      silc_hash_table_del(schedule->fd_queue, SILC_32_TO_PTR(fd));
+    silc_hash_table_list_reset(&htl);
+
+    /* Delete from timeout queue */
+    silc_list_start(schedule->timeout_queue);
+    while ((task = silc_list_get(schedule->timeout_queue))) {
+      silc_list_del(schedule->timeout_queue, task);
+      silc_free(task);
+    }
 
-   int max_fd
+    return;
+  }
 
-       Number of maximum file descriptors for select(). This, as well, is
-       managed automatically by the scheduler and should be considered to 
-       be read-only field otherwise.
+  if (silc_likely(task->type == 1)) {
+    /* Delete from timeout queue */
+    silc_list_del(schedule->timeout_queue, task);
 
-   void *wakeup
+    /* Put to free list */
+    silc_list_add(schedule->free_tasks, task);
+  } else {
+    /* Delete from fd queue */
+    ftask = (SilcTaskFd)task;
+    silc_hash_table_del(schedule->fd_queue, SILC_32_TO_PTR(ftask->fd));
+  }
+}
 
-       System specific wakeup context. On multi-threaded environments the
-       scheduler needs to be wakenup (in the thread) when tasks are added
-       or removed. This is initialized by silc_schedule_wakeup_init.
+/* Timeout freelist garbage collection */
 
-*/
-struct SilcScheduleStruct {
-  SilcTaskQueue fd_queue;
-  SilcTaskQueue timeout_queue;
-  SilcTaskQueue generic_queue;
-  SilcScheduleFdList fd_list;
-  struct timeval *timeout;
-  bool valid;
-  fd_set in;
-  fd_set out;
-  int max_fd;
-  void *wakeup;
-  SILC_MUTEX_DEFINE(lock);
-};
-
-/* Initializes the scheduler. Sets the non-timeout task queue hook and
-   the timeout task queue hook. This must be called before the scheduler
-   is able to work. This will allocate the queue pointers if they are
-   not allocated. Returns the scheduler context that must be freed by
-   the silc_schedule_uninit function. */
-
-SilcSchedule silc_schedule_init(SilcTaskQueue *fd_queue,
-                               SilcTaskQueue *timeout_queue,
-                               SilcTaskQueue *generic_queue,
-                               int max_fd)
+SILC_TASK_CALLBACK(silc_schedule_timeout_gc)
+{
+  SilcTaskTimeout t;
+  int c;
+
+  if (!schedule->valid)
+    return;
+
+  SILC_LOG_DEBUG(("Timeout freelist garbage collection"));
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  if (silc_list_count(schedule->free_tasks) <= 10) {
+    SILC_SCHEDULE_UNLOCK(schedule);
+    silc_schedule_task_add_timeout(schedule, silc_schedule_timeout_gc,
+                                  schedule, 3600, 0);
+    return;
+  }
+  if (silc_list_count(schedule->timeout_queue) >
+      silc_list_count(schedule->free_tasks)) {
+    SILC_SCHEDULE_UNLOCK(schedule);
+    silc_schedule_task_add_timeout(schedule, silc_schedule_timeout_gc,
+                                  schedule, 3600, 0);
+    return;
+  }
+
+  c = silc_list_count(schedule->free_tasks) / 2;
+  if (c > silc_list_count(schedule->timeout_queue))
+    c = (silc_list_count(schedule->free_tasks) -
+        silc_list_count(schedule->timeout_queue));
+  if (silc_list_count(schedule->free_tasks) - c < 10)
+    c -= (10 - (silc_list_count(schedule->free_tasks) - c));
+
+  SILC_LOG_DEBUG(("Freeing %d unused tasks, leaving %d", c,
+                 silc_list_count(schedule->free_tasks) - c));
+
+  silc_list_start(schedule->free_tasks);
+  while ((t = silc_list_get(schedule->free_tasks)) && c-- > 0) {
+    silc_list_del(schedule->free_tasks, t);
+    silc_free(t);
+  }
+  silc_list_start(schedule->free_tasks);
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  silc_schedule_task_add_timeout(schedule, silc_schedule_timeout_gc,
+                                schedule, 3600, 0);
+}
+
+#ifdef SILC_DIST_INPLACE
+/* Print schedule statistics to stdout */
+
+void silc_schedule_stats(SilcSchedule schedule)
+{
+  SilcTaskFd ftask;
+  fprintf(stdout, "Schedule %p statistics:\n\n", schedule);
+  fprintf(stdout, "Num FD tasks         : %lu (%lu bytes allocated)\n",
+         silc_hash_table_count(schedule->fd_queue),
+         sizeof(*ftask) * silc_hash_table_count(schedule->fd_queue));
+  fprintf(stdout, "Num Timeout tasks    : %d (%d bytes allocated)\n",
+         silc_list_count(schedule->timeout_queue),
+         sizeof(struct SilcTaskTimeoutStruct) *
+         silc_list_count(schedule->timeout_queue));
+  fprintf(stdout, "Num Timeout freelist : %d (%d bytes allocated)\n",
+         silc_list_count(schedule->free_tasks),
+         sizeof(struct SilcTaskTimeoutStruct) *
+         silc_list_count(schedule->free_tasks));
+}
+#endif /* SILC_DIST_INPLACE */
+
+/****************************** Public API **********************************/
+
+/* Initializes the scheduler. This returns the scheduler context that
+   is given as arugment usually to all silc_schedule_* functions.
+   The `max_tasks' indicates the number of maximum tasks that the
+   scheduler can handle. The `app_context' is application specific
+   context that is delivered to task callbacks. */
+
+SilcSchedule silc_schedule_init(int max_tasks, void *app_context)
 {
   SilcSchedule schedule;
-  int i;
 
   SILC_LOG_DEBUG(("Initializing scheduler"));
 
   schedule = silc_calloc(1, sizeof(*schedule));
+  if (!schedule)
+    return NULL;
+
+  schedule->fd_queue =
+    silc_hash_table_alloc(0, silc_hash_uint, NULL, NULL, NULL,
+                         silc_schedule_fd_destructor, NULL, TRUE);
+  if (!schedule->fd_queue) {
+    silc_free(schedule);
+    return NULL;
+  }
 
-  /* Register the task queues if they are not registered already. In SILC
-     we have by default three task queues. One task queue for non-timeout
-     tasks which perform different kind of I/O on file descriptors, timeout
-     task queue for timeout tasks, and, generic non-timeout task queue whose
-     tasks apply to all connections. */
-  if (!*fd_queue)
-    silc_task_queue_alloc(schedule, fd_queue, TRUE);
-  if (!*timeout_queue)
-    silc_task_queue_alloc(schedule, timeout_queue, TRUE);
-  if (!*generic_queue)
-    silc_task_queue_alloc(schedule, generic_queue, TRUE);
-
-  /* Initialize the scheduler */
-  schedule->fd_queue = *fd_queue;
-  schedule->timeout_queue = *timeout_queue;
-  schedule->generic_queue = *generic_queue;
-  schedule->fd_list.fd = silc_calloc(max_fd, sizeof(*schedule->fd_list.fd));
-  schedule->fd_list.last_fd = 0;
-  schedule->fd_list.max_fd = max_fd;
-  schedule->timeout = NULL;
+  silc_list_init(schedule->timeout_queue, struct SilcTaskStruct, next);
+  silc_list_init(schedule->free_tasks, struct SilcTaskStruct, next);
+
+  schedule->app_context = app_context;
   schedule->valid = TRUE;
-  FD_ZERO(&schedule->in);
-  FD_ZERO(&schedule->out);
-  schedule->max_fd = -1;
-  for (i = 0; i < max_fd; i++)
-    schedule->fd_list.fd[i] = -1;
+  schedule->max_tasks = max_tasks;
 
+  /* Allocate scheduler lock */
   silc_mutex_alloc(&schedule->lock);
 
-  /* Initialize the wakeup */
-  schedule->wakeup = silc_schedule_wakeup_init(schedule->fd_queue);
+  /* Initialize the platform specific scheduler. */
+  schedule->internal = schedule_ops.init(schedule, app_context);
+  if (!schedule->internal) {
+    silc_hash_table_free(schedule->fd_queue);
+    silc_mutex_free(schedule->lock);
+    silc_free(schedule);
+    return NULL;
+  }
+
+  /* Timeout freelist garbage collection */
+  silc_schedule_task_add_timeout(schedule, silc_schedule_timeout_gc,
+                                schedule, 3600, 0);
 
   return schedule;
 }
@@ -196,487 +361,558 @@ SilcSchedule silc_schedule_init(SilcTaskQueue *fd_queue,
    scheduler could not be uninitialized. This happens when the scheduler
    is still valid and silc_schedule_stop has not been called. */
 
-bool silc_schedule_uninit(SilcSchedule schedule)
+SilcBool silc_schedule_uninit(SilcSchedule schedule)
 {
+  SilcTask task;
 
   SILC_LOG_DEBUG(("Uninitializing scheduler"));
 
   if (schedule->valid == TRUE)
     return FALSE;
 
+  /* Dispatch all timeouts before going away */
+  SILC_SCHEDULE_LOCK(schedule);
+  silc_schedule_dispatch_timeout(schedule, TRUE);
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  /* Deliver signals before going away */
+  if (schedule->signal_tasks) {
+    schedule_ops.signals_call(schedule, schedule->internal);
+    schedule->signal_tasks = FALSE;
+  }
+
   /* Unregister all tasks */
-  if (schedule->fd_queue)
-    silc_task_remove(schedule->fd_queue, SILC_ALL_TASKS);
-  if (schedule->timeout_queue)
-    silc_task_remove(schedule->timeout_queue, SILC_ALL_TASKS);
-  if (schedule->generic_queue)
-    silc_task_remove(schedule->generic_queue, SILC_ALL_TASKS);
+  silc_schedule_task_del(schedule, SILC_ALL_TASKS);
+  silc_schedule_task_remove(schedule, SILC_ALL_TASKS);
+
+  /* Delete timeout task freelist */
+  silc_list_start(schedule->free_tasks);
+  while ((task = silc_list_get(schedule->free_tasks)))
+    silc_free(task);
 
   /* Unregister all task queues */
-  if (schedule->fd_queue)
-    silc_task_queue_free(schedule->fd_queue);
-  if (schedule->timeout_queue)
-    silc_task_queue_free(schedule->timeout_queue);
-  if (schedule->generic_queue)
-    silc_task_queue_free(schedule->generic_queue);
-
-  /* Clear the fd list */
-  if (schedule->fd_list.fd) {
-    memset(schedule->fd_list.fd, -1, schedule->fd_list.max_fd);
-    silc_free(schedule->fd_list.fd);
-  }
+  silc_hash_table_free(schedule->fd_queue);
 
-  /* Uninit the wakeup */
-  silc_schedule_wakeup_uninit(schedule->wakeup);
+  /* Uninit the platform specific scheduler. */
+  schedule_ops.uninit(schedule, schedule->internal);
 
   silc_mutex_free(schedule->lock);
+  silc_free(schedule);
 
   return TRUE;
 }
 
-/* Stops the schedule even if it is not supposed to be stopped yet. 
-   After calling this, one should call silc_schedule_uninit (after the 
+/* Stops the schedule even if it is not supposed to be stopped yet.
+   After calling this, one should call silc_schedule_uninit (after the
    silc_schedule has returned). */
 
 void silc_schedule_stop(SilcSchedule schedule)
 {
   SILC_LOG_DEBUG(("Stopping scheduler"));
+  SILC_SCHEDULE_LOCK(schedule);
   schedule->valid = FALSE;
+  SILC_SCHEDULE_UNLOCK(schedule);
 }
 
-/* Sets a file descriptor to be listened by select() in scheduler. One can
-   call this directly if wanted. This can be called multiple times for
-   one file descriptor to set different iomasks. */
+/* Runs the scheduler once and then returns.   Must be called locked. */
 
-void silc_schedule_set_listen_fd(SilcSchedule schedule, int fd, uint32 iomask)
+static SilcBool silc_schedule_iterate(SilcSchedule schedule, int timeout_usecs)
 {
-  silc_mutex_lock(schedule->lock);
+  struct timeval timeout;
+  int ret;
+
+  do {
+    SILC_LOG_DEBUG(("In scheduler loop"));
+
+    /* Deliver signals if any has been set to be called */
+    if (silc_unlikely(schedule->signal_tasks)) {
+      SILC_SCHEDULE_UNLOCK(schedule);
+      schedule_ops.signals_call(schedule, schedule->internal);
+      schedule->signal_tasks = FALSE;
+      SILC_SCHEDULE_LOCK(schedule);
+    }
+
+    /* Check if scheduler is valid */
+    if (silc_unlikely(schedule->valid == FALSE)) {
+      SILC_LOG_DEBUG(("Scheduler not valid anymore, exiting"));
+      return FALSE;
+    }
+
+    /* Calculate next timeout for silc_select().  This is the timeout value
+       when at earliest some of the timeout tasks expire.  This may dispatch
+       already expired timeouts. */
+    silc_schedule_select_timeout(schedule);
+
+    /* Check if scheduler is valid */
+    if (silc_unlikely(schedule->valid == FALSE)) {
+      SILC_LOG_DEBUG(("Scheduler not valid anymore, exiting"));
+      return FALSE;
+    }
+
+    if (timeout_usecs >= 0) {
+      timeout.tv_sec = 0;
+      timeout.tv_usec = timeout_usecs;
+      schedule->timeout = timeout;
+      schedule->has_timeout = TRUE;
+    }
+
+    /* This is the main silc_select(). The program blocks here until some
+       of the selected file descriptors change status or the selected
+       timeout expires. */
+    SILC_LOG_DEBUG(("Select"));
+    ret = schedule_ops.schedule(schedule, schedule->internal);
+
+    if (silc_likely(ret == 0)) {
+      /* Timeout */
+      SILC_LOG_DEBUG(("Running timeout tasks"));
+      if (silc_likely(silc_list_count(schedule->timeout_queue)))
+       silc_schedule_dispatch_timeout(schedule, FALSE);
+      continue;
+
+    } else if (silc_likely(ret > 0)) {
+      /* There is some data available now */
+      SILC_LOG_DEBUG(("Running fd tasks"));
+      silc_schedule_dispatch_fd(schedule);
+      continue;
+
+    } else {
+      /* Error or special case handling */
+      if (errno == EINTR)
+       continue;
+      if (ret == -2)
+       break;
 
-  schedule->fd_list.fd[fd] = iomask;
-  
-  if (fd > schedule->fd_list.last_fd)
-    schedule->fd_list.last_fd = fd;
+      SILC_LOG_ERROR(("Error in select()/poll(): %s", strerror(errno)));
+      continue;
+    }
+  } while (timeout_usecs == -1);
 
-  silc_mutex_unlock(schedule->lock);
+  return TRUE;
 }
 
-/* Removes a file descriptor from listen list. */
+/* Runs the scheduler once and then returns. */
+
+SilcBool silc_schedule_one(SilcSchedule schedule, int timeout_usecs)
+{
+  SilcBool ret;
+  SILC_SCHEDULE_LOCK(schedule);
+  ret = silc_schedule_iterate(schedule, timeout_usecs);
+  SILC_SCHEDULE_UNLOCK(schedule);
+  return ret;
+}
+
+/* Runs the scheduler and blocks here.  When this returns the scheduler
+   has ended. */
+
+#ifndef SILC_SYMBIAN
+void silc_schedule(SilcSchedule schedule)
+{
+  SILC_LOG_DEBUG(("Running scheduler"));
+
+  /* Start the scheduler loop */
+  SILC_SCHEDULE_LOCK(schedule);
+  silc_schedule_iterate(schedule, -1);
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+#endif /* !SILC_SYMBIAN */
+
+/* Wakes up the scheduler. This is used only in multi-threaded
+   environments where threads may add new tasks or remove old tasks
+   from task queues. This is called to wake up the scheduler in the
+   main thread so that it detects the changes in the task queues.
+   If threads support is not compiled in this function has no effect.
+   Implementation of this function is platform specific. */
+
+void silc_schedule_wakeup(SilcSchedule schedule)
+{
+#ifdef SILC_THREADS
+  SILC_LOG_DEBUG(("Wakeup scheduler"));
+  SILC_SCHEDULE_LOCK(schedule);
+  schedule_ops.wakeup(schedule, schedule->internal);
+  SILC_SCHEDULE_UNLOCK(schedule);
+#endif
+}
 
-void silc_schedule_unset_listen_fd(SilcSchedule schedule, int fd)
+/* Returns the application specific context that was saved into the
+   scheduler in silc_schedule_init function.  The context is also
+   returned to application in task callback functions, but this function
+   may be used to get it as well if needed. */
+
+void *silc_schedule_get_context(SilcSchedule schedule)
 {
-  silc_mutex_lock(schedule->lock);
+  return schedule->app_context;
+}
 
-  schedule->fd_list.fd[fd] = -1;
-  
-  if (fd == schedule->fd_list.last_fd) {
-    int i;
+/* Add new task to the scheduler */
 
-    for (i = fd; i >= 0; i--)
-      if (schedule->fd_list.fd[i] != -1)
+SilcTask silc_schedule_task_add(SilcSchedule schedule, SilcUInt32 fd,
+                               SilcTaskCallback callback, void *context,
+                               long seconds, long useconds,
+                               SilcTaskType type)
+{
+  SilcTask task = NULL;
+
+  if (silc_unlikely(!schedule->valid))
+    return NULL;
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  if (silc_likely(type == SILC_TASK_TIMEOUT)) {
+    SilcTaskTimeout tmp, prev, ttask;
+    SilcList list;
+
+    silc_list_start(schedule->free_tasks);
+    ttask = silc_list_get(schedule->free_tasks);
+    if (silc_unlikely(!ttask)) {
+      ttask = silc_calloc(1, sizeof(*ttask));
+      if (silc_unlikely(!ttask))
+       goto out;
+    } else
+      silc_list_del(schedule->free_tasks, ttask);
+
+    ttask->header.type = 1;
+    ttask->header.callback = callback;
+    ttask->header.context = context;
+    ttask->header.valid = TRUE;
+
+    /* Add timeout */
+    silc_gettimeofday(&ttask->timeout);
+    if ((seconds + useconds) > 0) {
+      ttask->timeout.tv_sec += seconds + (useconds / 1000000L);
+      ttask->timeout.tv_usec += (useconds % 1000000L);
+      if (ttask->timeout.tv_usec >= 1000000L) {
+       ttask->timeout.tv_sec += 1;
+       ttask->timeout.tv_usec -= 1000000L;
+      }
+    }
+
+    SILC_LOG_DEBUG(("New timeout task %p: sec=%d, usec=%d", ttask,
+                   seconds, useconds));
+
+    /* Add task to correct spot so that the first task in the list has
+       the earliest timeout. */
+    list = schedule->timeout_queue;
+    silc_list_start(list);
+    prev = NULL;
+    while ((tmp = silc_list_get(list)) != SILC_LIST_END) {
+      /* If we have shorter timeout, we have found our spot */
+      if (silc_compare_timeval(&ttask->timeout, &tmp->timeout) < 0) {
+       silc_list_insert(schedule->timeout_queue, prev, ttask);
        break;
+      }
+      prev = tmp;
+    }
+    if (!tmp)
+      silc_list_add(schedule->timeout_queue, ttask);
+
+    task = (SilcTask)ttask;
+
+  } else if (silc_likely(type == SILC_TASK_FD)) {
+    SilcTaskFd ftask;
+
+    /* Check if fd is already added */
+    if (silc_unlikely(silc_hash_table_find(schedule->fd_queue,
+                                          SILC_32_TO_PTR(fd),
+                                          NULL, (void *)&task))) {
+      if (task->valid)
+        goto out;
+
+      /* Remove invalid task.  We must have unique fd key to hash table. */
+      silc_schedule_task_remove(schedule, task);
+    }
+
+    /* Check max tasks */
+    if (silc_unlikely(schedule->max_tasks > 0 &&
+                     silc_hash_table_count(schedule->fd_queue) >=
+                     schedule->max_tasks)) {
+      SILC_LOG_WARNING(("Scheduler task limit reached: cannot add new task"));
+      task = NULL;
+      goto out;
+    }
+
+    ftask = silc_calloc(1, sizeof(*ftask));
+    if (silc_unlikely(!ftask)) {
+      task = NULL;
+      goto out;
+    }
+
+    SILC_LOG_DEBUG(("New fd task %p fd=%d", ftask, fd));
+
+    ftask->header.type = 0;
+    ftask->header.callback = callback;
+    ftask->header.context = context;
+    ftask->header.valid = TRUE;
+    ftask->events = SILC_TASK_READ;
+    ftask->fd = fd;
+
+    /* Add task and schedule it */
+    if (!silc_hash_table_add(schedule->fd_queue, SILC_32_TO_PTR(fd), ftask)) {
+      silc_free(ftask);
+      task = NULL;
+      goto out;
+    }
+    if (!schedule_ops.schedule_fd(schedule, schedule->internal,
+                                 ftask, ftask->events)) {
+      silc_hash_table_del(schedule->fd_queue, SILC_32_TO_PTR(fd));
+      task = NULL;
+      goto out;
+    }
+
+    task = (SilcTask)ftask;
+
+  } else if (silc_unlikely(type == SILC_TASK_SIGNAL)) {
+    SILC_SCHEDULE_UNLOCK(schedule);
+    schedule_ops.signal_register(schedule, schedule->internal, fd,
+                                callback, context);
+    return NULL;
+  }
+
+ out:
+  SILC_SCHEDULE_UNLOCK(schedule);
 
-    schedule->fd_list.last_fd = i < 0 ? 0 : i;
+#ifdef SILC_SYMBIAN
+  /* On symbian we wakeup scheduler immediately after adding timeout task
+     in case the task is added outside the scheduler loop (in some active
+     object). */
+  if (task && task->type == 1)
+    silc_schedule_wakeup(schedule);
+#endif /* SILC_SYMBIAN */
+
+  return task;
+}
+
+/* Invalidates task */
+
+SilcBool silc_schedule_task_del(SilcSchedule schedule, SilcTask task)
+{
+  if (silc_unlikely(task == SILC_ALL_TASKS)) {
+    SilcHashTableList htl;
+
+    SILC_LOG_DEBUG(("Unregister all tasks"));
+
+    SILC_SCHEDULE_LOCK(schedule);
+
+    /* Delete from fd queue */
+    silc_hash_table_list(schedule->fd_queue, &htl);
+    while (silc_hash_table_get(&htl, NULL, (void *)&task))
+      task->valid = FALSE;
+    silc_hash_table_list_reset(&htl);
+
+    /* Delete from timeout queue */
+    silc_list_start(schedule->timeout_queue);
+    while ((task = (SilcTask)silc_list_get(schedule->timeout_queue))
+          != SILC_LIST_END)
+      task->valid = FALSE;
+
+    SILC_SCHEDULE_UNLOCK(schedule);
+    return TRUE;
   }
 
-  silc_mutex_unlock(schedule->lock);
+  SILC_LOG_DEBUG(("Unregistering task %p", task));
+  SILC_SCHEDULE_LOCK(schedule);
+  task->valid = FALSE;
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  return TRUE;
 }
 
-/* Executes tasks matching the file descriptor set by select(). The task
-   remains on the task queue after execution. Invalid tasks are removed 
-   here from the task queue. This macro is used by silc_schedule function. 
-   We don't have to care about the tasks priority here because the tasks
-   are sorted in their priority order already at the registration phase. */
-
-#define SILC_SCHEDULE_RUN_TASKS                                                   \
-do {                                                                      \
-  queue = schedule->fd_queue;                                             \
-  if (queue && queue->valid == TRUE && queue->task) {                     \
-    task = queue->task;                                                           \
-                                                                          \
-    /* Walk thorugh all tasks in the particular task queue and            \
-       execute the callback functions of those tasks matching the         \
-       fd set by select(). */                                             \
-    while(1) {                                                            \
-      /* Validity of the task is checked always before and after          \
-        execution beacuse the task might have been unregistered           \
-        in the callback function, ie. it is not valid anymore. */         \
-                                                                          \
-      if (task->valid) {                                                  \
-       /* Task ready for reading */                                       \
-       if ((FD_ISSET(task->fd, &schedule->in)) &&                         \
-           (task->iomask & (1L << SILC_TASK_READ))) {                     \
-         task->callback(queue, SILC_TASK_READ, task->context, task->fd);  \
-          is_run = TRUE;                                                  \
-       }                                                                  \
-      }                                                                   \
-                                                                          \
-      if (task->valid) {                                                  \
-       /* Task ready for writing */                                       \
-       if ((FD_ISSET(task->fd, &schedule->out)) &&                        \
-           (task->iomask & (1L << SILC_TASK_WRITE))) {                    \
-         task->callback(queue, SILC_TASK_WRITE, task->context, task->fd); \
-          is_run = TRUE;                                                  \
-       }                                                                  \
-      }                                                                           \
-                                                                          \
-      if (!task->valid) {                                                 \
-       /* Invalid (unregistered) tasks are removed from the               \
-          task queue. */                                                  \
-       if (queue->task == task->next) {                                   \
-         silc_task_remove(queue, task);                                   \
-          break;                                                          \
-        }                                                                 \
-                                                                          \
-        task = task->next;                                                \
-        silc_task_remove(queue, task->prev);                              \
-        continue;                                                         \
-      }                                                                           \
-                                                                          \
-      /* Break if there isn't more tasks in the queue */                  \
-      if (queue->task == task->next)                                      \
-        break;                                                            \
-                                                                          \
-      task = task->next;                                                  \
-    }                                                                     \
-  }                                                                       \
-} while(0)
-
-/* Selects tasks to be listened by select(). These are the non-timeout
-   tasks. This checks the scheduler's fd list. This macro is used by 
-   silc_schedule function. */
-
-#define SILC_SCHEDULE_SELECT_TASKS                             \
-do {                                                           \
-  for (i = 0; i <= schedule->fd_list.last_fd; i++) {           \
-    if (schedule->fd_list.fd[i] != -1) {                       \
-                                                               \
-      /* Set the max fd value for select() to listen */                \
-      if (i > schedule->max_fd)                                        \
-       schedule->max_fd = i;                                   \
-                                                               \
-      /* Add tasks for reading */                              \
-      if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_READ)))  \
-       FD_SET(i, &schedule->in);                               \
-                                                               \
-      /* Add tasks for writing */                              \
-      if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_WRITE))) \
-       FD_SET(i, &schedule->out);                              \
-    }                                                          \
-  }                                                            \
-} while(0)
+/* Invalidate task by fd */
 
-/* Executes all tasks whose timeout has expired. The task is removed from
-   the task queue after the callback function has returned. Also, invalid
-   tasks are removed here. The current time must be get before calling this
-   macro. This macro is used by silc_schedule function. We don't have to
-   care about priorities because tasks are already sorted in their priority
-   order at the registration phase. */
-
-#define SILC_SCHEDULE_RUN_TIMEOUT_TASKS                                        \
-do {                                                                   \
-  queue = schedule->timeout_queue;                                     \
-  if (queue && queue->valid == TRUE && queue->task) {                  \
-    task = queue->task;                                                        \
-                                                                       \
-    /* Walk thorugh all tasks in the particular task queue             \
-       and run all the expired tasks. */                               \
-    while(1) {                                                         \
-      /* Execute the task if the timeout has expired */                        \
-      if (silc_task_timeout_compare(&task->timeout, &curtime)) {       \
-                                                                       \
-        /* Task ready for reading */                                   \
-        if (task->valid) {                                             \
-          if ((task->iomask & (1L << SILC_TASK_READ)))                 \
-           task->callback(queue, SILC_TASK_READ,                       \
-                          task->context, task->fd);                    \
-       }                                                               \
-                                                                       \
-        /* Task ready for writing */                                   \
-        if (task->valid) {                                             \
-          if ((task->iomask & (1L << SILC_TASK_WRITE)))                        \
-            task->callback(queue, SILC_TASK_WRITE,                     \
-                          task->context, task->fd);                    \
-        }                                                              \
-                                                                       \
-        /* Break if there isn't more tasks in the queue */             \
-       if (queue->task == task->next) {                                \
-         /* Remove the task from queue */                              \
-         silc_task_remove(queue, task);                                \
-         break;                                                        \
-        }                                                              \
-                                                                       \
-        task = task->next;                                             \
-                                                                       \
-        /* Remove the task from queue */                               \
-        silc_task_remove(queue, task->prev);                           \
-      } else {                                                         \
-        /* The timeout hasn't expired, check for next one */           \
-                                                                       \
-        /* Break if there isn't more tasks in the queue */             \
-        if (queue->task == task->next)                                 \
-          break;                                                       \
-                                                                       \
-        task = task->next;                                             \
-      }                                                                        \
-    }                                                                  \
-  }                                                                    \
-} while(0)
-
-/* Calculates next timeout for select(). This is the timeout value
-   when at earliest some of the timeout tasks expire. If this is in the
-   past, they will be run now. This macro is used by the silc_schedule
-   function. */
-
-#define SILC_SCHEDULE_SELECT_TIMEOUT                                       \
-do {                                                                       \
-  if (schedule->timeout_queue && schedule->timeout_queue->valid == TRUE) {  \
-    queue = schedule->timeout_queue;                                       \
-    task = NULL;                                                           \
-                                                                           \
-    /* Get the current time */                                             \
-    silc_gettimeofday(&curtime);                                           \
-    schedule->timeout = NULL;                                              \
-                                                                           \
-    /* First task in the task queue has always the smallest timeout. */            \
-    task = queue->task;                                                            \
-    while(1) {                                                             \
-      if (task && task->valid == TRUE) {                                   \
-                                                                           \
-       /* If the timeout is in past, we will run the task and all other    \
-          timeout tasks from the past. */                                  \
-       if (silc_task_timeout_compare(&task->timeout, &curtime)) {          \
-         SILC_SCHEDULE_RUN_TIMEOUT_TASKS;                                  \
-                                                                           \
-         /* The task(s) has expired and doesn't exist on the task queue    \
-            anymore. We continue with new timeout. */                      \
-          queue = schedule->timeout_queue;                                 \
-          task = queue->task;                                              \
-          if (task == NULL || task->valid == FALSE)                        \
-            break;                                                         \
-         goto cont;                                                        \
-        } else {                                                           \
- cont:                                                                     \
-          /* Calculate the next timeout for select() */                            \
-          queue->timeout.tv_sec = task->timeout.tv_sec - curtime.tv_sec;    \
-          queue->timeout.tv_usec = task->timeout.tv_usec - curtime.tv_usec; \
-         if (queue->timeout.tv_sec < 0)                                    \
-            queue->timeout.tv_sec = 0;                                     \
-                                                                           \
-          /* We wouldn't want to go under zero, check for it. */           \
-          if (queue->timeout.tv_usec < 0) {                                \
-            queue->timeout.tv_sec -= 1;                                            \
-           if (queue->timeout.tv_sec < 0)                                  \
-              queue->timeout.tv_sec = 0;                                   \
-            queue->timeout.tv_usec += 1000000L;                                    \
-          }                                                                \
-        }                                                                  \
-        /* We've got the timeout value */                                  \
-       break;                                                              \
-      }        else {                                                              \
-        /* Task is not valid, remove it and try next one. */               \
-       silc_task_remove(queue, task);                                      \
-        task = queue->task;                                                \
-        if (queue->task == NULL)                                           \
-          break;                                                           \
-      }                                                                            \
-    }                                                                      \
-    /* Save the timeout */                                                 \
-    if (task)                                                              \
-      schedule->timeout = &queue->timeout;                                 \
-  }                                                                        \
-} while(0)
-
-/* Execute generic tasks. These are executed only and only if for the
-   specific fd there wasn't other non-timeout tasks. This checks the earlier
-   set fd list, thus the generic tasks apply to all specified fd's. All the
-   generic tasks are executed at once. */
-
-#define SILC_SCHEDULE_RUN_GENERIC_TASKS                                             \
-do {                                                                        \
-  if (is_run == FALSE) {                                                    \
-    SILC_LOG_DEBUG(("Running generic tasks"));                              \
-    silc_mutex_lock(schedule->lock);                                        \
-    for (i = 0; i <= schedule->fd_list.last_fd; i++)                        \
-      if (schedule->fd_list.fd[i] != -1) {                                  \
-                                                                            \
-       /* Check whether this fd is select()ed. */                           \
-       if ((FD_ISSET(i, &schedule->in)) || (FD_ISSET(i, &schedule->out))) { \
-                                                                            \
-         /* It was selected. Now find the tasks from task queue and execute \
-            all generic tasks. */                                           \
-         if (schedule->generic_queue && schedule->generic_queue->valid) {   \
-           queue = schedule->generic_queue;                                 \
-                                                                            \
-           if (!queue->task)                                                \
-             break;                                                         \
-                                                                            \
-           task = queue->task;                                              \
-                                                                            \
-           while(1) {                                                       \
-             /* Validity of the task is checked always before and after     \
-                execution beacuse the task might have been unregistered     \
-                in the callback function, ie. it is not valid anymore. */   \
-                                                                            \
-             if (task->valid && schedule->fd_list.fd[i] != -1) {            \
-               /* Task ready for reading */                                 \
-               if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_READ))) {    \
-                  silc_mutex_unlock(schedule->lock);                        \
-                 task->callback(queue, SILC_TASK_READ,                      \
-                                task->context, i);                          \
-                  silc_mutex_lock(schedule->lock);                          \
-               }                                                            \
-             }                                                              \
-                                                                            \
-             if (task->valid && schedule->fd_list.fd[i] != -1) {            \
-               /* Task ready for writing */                                 \
-               if ((schedule->fd_list.fd[i] & (1L << SILC_TASK_WRITE))) {   \
-                  silc_mutex_unlock(schedule->lock);                        \
-                 task->callback(queue, SILC_TASK_WRITE,                     \
-                                task->context, i);                          \
-                  silc_mutex_lock(schedule->lock);                          \
-               }                                                            \
-             }                                                              \
-                                                                            \
-             if (!task->valid) {                                            \
-               /* Invalid (unregistered) tasks are removed from the         \
-                  task queue. */                                            \
-               if (queue->task == task->next) {                             \
-                 silc_task_remove(queue, task);                             \
-                 break;                                                     \
-               }                                                            \
-                                                                            \
-               task = task->next;                                           \
-               silc_task_remove(queue, task->prev);                         \
-               continue;                                                    \
-             }                                                              \
-                                                                            \
-             /* Break if there isn't more tasks in the queue */             \
-             if (queue->task == task->next)                                 \
-               break;                                                       \
-                                                                            \
-             task = task->next;                                             \
-           }                                                                \
-         }                                                                  \
-       }                                                                    \
-      }                                                                             \
-    silc_mutex_unlock(schedule->lock);                                      \
-  }                                                                         \
-} while(0)
-
-bool silc_schedule_one(SilcSchedule schedule, int timeout_usecs)
+SilcBool silc_schedule_task_del_by_fd(SilcSchedule schedule, SilcUInt32 fd)
 {
-  struct timeval timeout;
-  int is_run, i;
-  SilcTask task;
-  SilcTaskQueue queue;
-  struct timeval curtime;
-  int ret;
+  SilcTask task = NULL;
+  SilcBool ret = FALSE;
 
-  SILC_LOG_DEBUG(("In scheduler loop"));
+  SILC_LOG_DEBUG(("Unregister task by fd %d", fd));
 
-  /* If the task queues aren't initialized or we aren't valid anymore
-     we will return */
-  if ((!schedule->fd_queue && !schedule->timeout_queue 
-       && !schedule->generic_queue) || schedule->valid == FALSE) {
-    SILC_LOG_DEBUG(("Scheduler not valid anymore, exiting"));
-    return FALSE;
+  SILC_SCHEDULE_LOCK(schedule);
+
+  /* fd is unique, so there is only one task with this fd in the table */
+  if (silc_likely(silc_hash_table_find(schedule->fd_queue,
+                                      SILC_32_TO_PTR(fd), NULL,
+                                      (void *)&task))) {
+    SILC_LOG_DEBUG(("Deleting task %p", task));
+    task->valid = FALSE;
+    ret = TRUE;
+  }
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  /* If it is signal, remove it */
+  if (silc_unlikely(!task)) {
+    schedule_ops.signal_unregister(schedule, schedule->internal, fd);
+    ret = TRUE;
   }
 
-  /* Clear everything */
-  FD_ZERO(&schedule->in);
-  FD_ZERO(&schedule->out);
-  schedule->max_fd = -1;
-  is_run = FALSE;
+  return ret;
+}
 
-  /* Calculate next timeout for select(). This is the timeout value
-     when at earliest some of the timeout tasks expire. */
-  SILC_SCHEDULE_SELECT_TIMEOUT;
+/* Invalidate task by task callback. */
 
-  silc_mutex_lock(schedule->lock);
+SilcBool silc_schedule_task_del_by_callback(SilcSchedule schedule,
+                                           SilcTaskCallback callback)
+{
+  SilcTask task;
+  SilcHashTableList htl;
+  SilcList list;
+  SilcBool ret = FALSE;
 
-  /* Add the file descriptors to the fd sets. These are the non-timeout
-     tasks. The select() listens to these file descriptors. */
-  SILC_SCHEDULE_SELECT_TASKS;
+  SILC_LOG_DEBUG(("Unregister task by callback"));
 
-  if (schedule->max_fd == -1 && !schedule->timeout)
-    return FALSE;
+  SILC_SCHEDULE_LOCK(schedule);
 
-  if (schedule->timeout) {
-    SILC_LOG_DEBUG(("timeout: sec=%d, usec=%d", schedule->timeout->tv_sec,
-                   schedule->timeout->tv_usec));
+  /* Delete from fd queue */
+  silc_hash_table_list(schedule->fd_queue, &htl);
+  while (silc_hash_table_get(&htl, NULL, (void *)&task)) {
+    if (task->callback == callback) {
+      task->valid = FALSE;
+      ret = TRUE;
+    }
+  }
+  silc_hash_table_list_reset(&htl);
+
+  /* Delete from timeout queue */
+  list = schedule->timeout_queue;
+  silc_list_start(list);
+  while ((task = (SilcTask)silc_list_get(list))) {
+    if (task->callback == callback) {
+      task->valid = FALSE;
+      ret = TRUE;
+    }
   }
 
-  if (timeout_usecs >= 0) {
-    timeout.tv_sec = 0;
-    timeout.tv_usec = timeout_usecs;
-    schedule->timeout = &timeout;
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  return ret;
+}
+
+/* Invalidate task by context. */
+
+SilcBool silc_schedule_task_del_by_context(SilcSchedule schedule,
+                                          void *context)
+{
+  SilcTask task;
+  SilcHashTableList htl;
+  SilcList list;
+  SilcBool ret = FALSE;
+
+  SILC_LOG_DEBUG(("Unregister task by context"));
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  /* Delete from fd queue */
+  silc_hash_table_list(schedule->fd_queue, &htl);
+  while (silc_hash_table_get(&htl, NULL, (void *)&task)) {
+    if (task->context == context) {
+      task->valid = FALSE;
+      ret = TRUE;
+    }
+  }
+  silc_hash_table_list_reset(&htl);
+
+  /* Delete from timeout queue */
+  list = schedule->timeout_queue;
+  silc_list_start(list);
+  while ((task = (SilcTask)silc_list_get(list))) {
+    if (task->context == context) {
+      ret = TRUE;
+      task->valid = FALSE;
+    }
   }
 
-  silc_mutex_unlock(schedule->lock);
+  SILC_SCHEDULE_UNLOCK(schedule);
 
-  /* This is the main select(). The program blocks here until some
-     of the selected file descriptors change status or the selected
-     timeout expires. */
-  SILC_LOG_DEBUG(("Select"));
-  ret = silc_select(schedule->max_fd + 1, &schedule->in,
-                   &schedule->out, 0, schedule->timeout);
+  return ret;
+}
 
-  switch (ret) {
-  case -1:
-    /* Error */
-    if (errno == EINTR)
-      break;
-    SILC_LOG_ERROR(("Error in select(): %s", strerror(errno)));
-    break;
-  case 0:
-    /* Timeout */
-    SILC_LOG_DEBUG(("Running timeout tasks"));
-    silc_gettimeofday(&curtime);
-    SILC_SCHEDULE_RUN_TIMEOUT_TASKS;
-    break;
-  default:
-    /* There is some data available now */
-    SILC_LOG_DEBUG(("Running non-timeout tasks"));
-    SILC_SCHEDULE_RUN_TASKS;
+/* Invalidate task by all */
 
-    SILC_SCHEDULE_RUN_GENERIC_TASKS;
-    break;
+SilcBool silc_schedule_task_del_by_all(SilcSchedule schedule, int fd,
+                                      SilcTaskCallback callback,
+                                      void *context)
+{
+  SilcTask task;
+  SilcList list;
+  SilcBool ret = FALSE;
+
+  SILC_LOG_DEBUG(("Unregister task by fd, callback and context"));
+
+  /* For fd task, callback and context is irrelevant as fd is unique */
+  if (fd)
+    return silc_schedule_task_del_by_fd(schedule, fd);
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  /* Delete from timeout queue */
+  list = schedule->timeout_queue;
+  silc_list_start(list);
+  while ((task = (SilcTask)silc_list_get(list))) {
+    if (task->callback == callback && task->context == context) {
+      task->valid = FALSE;
+      ret = TRUE;
+    }
   }
 
+  SILC_SCHEDULE_UNLOCK(schedule);
+
   return TRUE;
 }
 
-/* The SILC scheduler. This is actually the main routine in SILC programs.
-   When this returns the program is to be ended. Before this function can
-   be called, one must call silc_schedule_init function. */
+/* Sets a file descriptor to be listened by scheduler. One can call this
+   directly if wanted. This can be called multiple times for one file
+   descriptor to set different iomasks. */
 
-void silc_schedule(SilcSchedule schedule)
+SilcBool silc_schedule_set_listen_fd(SilcSchedule schedule, SilcUInt32 fd,
+                                    SilcTaskEvent mask, SilcBool send_events)
 {
-  SILC_LOG_DEBUG(("Running scheduler"));
+  SilcTaskFd task;
 
-  if (schedule->valid == FALSE) {
-    SILC_LOG_ERROR(("Scheduler is not valid, stopping"));
-    return;
+  if (silc_unlikely(!schedule->valid))
+    return FALSE;
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  if (silc_hash_table_find(schedule->fd_queue, SILC_32_TO_PTR(fd),
+                          NULL, (void *)&task)) {
+    if (!schedule_ops.schedule_fd(schedule, schedule->internal, task, mask)) {
+      SILC_SCHEDULE_UNLOCK(schedule);
+      return FALSE;
+    }
+    task->events = mask;
+    if (silc_unlikely(send_events) && mask) {
+      task->revents = mask;
+      silc_schedule_dispatch_fd(schedule);
+    }
   }
 
-  /* Start the scheduler loop */
-  while (silc_schedule_one(schedule, -1)) 
-    ;
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  return TRUE;
 }
 
-/* Wakes up the scheduler. This is used only in multi-threaded
-   environments where threads may add new tasks or remove old tasks
-   from task queues. This is called to wake up the scheduler in the
-   main thread so that it detects the changes in the task queues.
-   If threads support is not compiled in this function has no effect.
-   Implementation of this function is platform specific. */
+/* Returns the file descriptor's current requested event mask. */
 
-void silc_schedule_wakeup(SilcSchedule schedule)
+SilcTaskEvent silc_schedule_get_fd_events(SilcSchedule schedule,
+                                         SilcUInt32 fd)
 {
-#ifdef SILC_THREADS
-  SILC_LOG_DEBUG(("Wakeup scheduler"));
-  silc_mutex_lock(schedule->lock);
-  silc_schedule_wakeup_internal(schedule->wakeup);
-  silc_mutex_unlock(schedule->lock);
-#endif
+  SilcTaskFd task;
+  SilcTaskEvent event = 0;
+
+  if (silc_unlikely(!schedule->valid))
+    return 0;
+
+  SILC_SCHEDULE_LOCK(schedule);
+  if (silc_hash_table_find(schedule->fd_queue, SILC_32_TO_PTR(fd),
+                          NULL, (void *)&task))
+    event = task->events;
+  SILC_SCHEDULE_UNLOCK(schedule);
+
+  return event;
+}
+
+/* Removes a file descriptor from listen list. */
+
+void silc_schedule_unset_listen_fd(SilcSchedule schedule, SilcUInt32 fd)
+{
+  silc_schedule_set_listen_fd(schedule, fd, 0, FALSE);
 }