Added SILC Server library.
[silc.git] / lib / silcutil / silcschedule.c
index 4a7522200075ba941c353f8c7c07570449c697a3..8c5cfd66bc361af4b2feb589d5c1328c81daae5c 100644 (file)
@@ -2,15 +2,14 @@
 
   silcschedule.c
 
-  Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
+  Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 1998 - 2000 Pekka Riikonen
+  Copyright (C) 1998 - 2005 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
 */
 /* $Id$ */
 
-#include "silcincludes.h"
+#include "silc.h"
+
+/* Platform specific implementation */
+extern const SilcScheduleOps schedule_ops;
+
+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);
 
-/* The actual schedule object. */
-static SilcSchedule schedule;
+/* Fd task hash table destructor */
+
+static void silc_schedule_fd_destructor(void *key, void *context,
+                                       void *user_context)
+{
+  silc_free(context);
+}
 
-/* Initializes the schedule. Sets the non-timeout task queue hook and
-   the timeout task queue hook. This must be called before the schedule
-   is able to work. */
+/* 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. */
 
-void silc_schedule_init(SilcTaskQueue *fd_queue,
-                       SilcTaskQueue *timeout_queue,
-                       SilcTaskQueue *generic_queue,
-                       int max_fd)
+SilcSchedule silc_schedule_init(int max_tasks, void *app_context)
 {
-  int i;
+  SilcSchedule schedule;
 
   SILC_LOG_DEBUG(("Initializing scheduler"));
 
-  /* 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(fd_queue, TRUE);
-  if (!*timeout_queue)
-    silc_task_queue_alloc(timeout_queue, TRUE);
-  if (!*generic_queue)
-    silc_task_queue_alloc(generic_queue, TRUE);
-
-  /* Initialize the schedule */
-  memset(&schedule, 0, sizeof(schedule));
-  schedule.fd_queue = *fd_queue;
-  schedule.timeout_queue = *timeout_queue;
-  schedule.generic_queue = *generic_queue;
-  schedule.fd_list.fd = silc_calloc(max_fd, sizeof(int));
-  schedule.fd_list.last_fd = 0;
-  schedule.fd_list.max_fd = max_fd;
-  schedule.timeout = NULL;
-  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 = 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)
+    return NULL;
+
+  silc_list_init(schedule->timeout_queue, struct SilcTaskTimeoutStruct, next);
+
+  schedule->app_context = app_context;
+  schedule->valid = TRUE;
+  schedule->max_tasks = max_tasks;
+
+  /* Allocate scheduler lock */
+  silc_mutex_alloc(&schedule->lock);
+
+  /* Initialize the platform specific scheduler. */
+  schedule->internal = schedule_ops.init(schedule, app_context);
+
+  return schedule;
 }
 
 /* Uninitializes the schedule. This is called when the program is ready
-   to end. This removes all tasks and task queues. */
+   to end. This removes all tasks and task queues. Returns FALSE if the
+   scheduler could not be uninitialized. This happens when the scheduler
+   is still valid and silc_schedule_stop has not been called. */
 
-int silc_schedule_uninit()
+SilcBool silc_schedule_uninit(SilcSchedule schedule)
 {
-
   SILC_LOG_DEBUG(("Uninitializing scheduler"));
 
-  if (schedule.valid == TRUE)
+  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_remove(schedule, SILC_ALL_TASKS);
+  silc_schedule_task_remove(schedule, SILC_ALL_TASKS);
 
   /* 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 platform specific scheduler. */
+  schedule_ops.uninit(schedule, schedule->internal);
+
+  silc_mutex_free(schedule->lock);
+  silc_free(schedule);
 
-  memset(&schedule, 'F', sizeof(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()
+void silc_schedule_stop(SilcSchedule schedule)
 {
   SILC_LOG_DEBUG(("Stopping scheduler"));
-
-  if (schedule.valid == TRUE)
-    schedule.valid = FALSE;
+  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. */
+/* Executes file descriptor tasks. Invalid tasks are removed here. */
 
-void silc_schedule_set_listen_fd(int fd, uint32 iomask)
+static void silc_schedule_dispatch_fd(SilcSchedule schedule)
 {
-  assert(schedule.valid != FALSE);
-  assert(fd < schedule.fd_list.max_fd);
-
-  schedule.fd_list.fd[fd] = iomask;
-  
-  if (fd > schedule.fd_list.last_fd)
-    schedule.fd_list.last_fd = fd;
+  SilcHashTableList htl;
+  SilcTask t;
+  SilcTaskFd task;
+  SilcUInt32 fd;
+
+  silc_hash_table_list(schedule->fd_queue, &htl);
+  while (silc_hash_table_get(&htl, (void **)&fd, (void **)&task)) {
+    t = (SilcTask)task;
+
+    if (!t->valid) {
+      silc_schedule_task_remove(schedule, t);
+      continue;
+    }
+    if (!task->events || !task->revents)
+      continue;
+
+    /* Is the task ready for reading */
+    if (task->revents & SILC_TASK_READ) {
+      SILC_SCHEDULE_UNLOCK(schedule);
+      t->callback(schedule, schedule->app_context, SILC_TASK_READ,
+                 task->fd, t->context);
+      SILC_SCHEDULE_LOCK(schedule);
+    }
+
+    /* Is the task ready for writing */
+    if (t->valid && task->revents & SILC_TASK_WRITE) {
+      SILC_SCHEDULE_UNLOCK(schedule);
+      t->callback(schedule, schedule->app_context, SILC_TASK_WRITE,
+                 task->fd, t->context);
+      SILC_SCHEDULE_LOCK(schedule);
+    }
+
+    /* Remove if task was invalidated in the task callback */
+    if (!t->valid)
+      silc_schedule_task_remove(schedule, t);
+  }
+  silc_hash_table_list_reset(&htl);
 }
 
-/* Removes a file descriptor from listen list. */
+/* 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. */
 
-void silc_schedule_unset_listen_fd(int fd)
+static void silc_schedule_dispatch_timeout(SilcSchedule schedule,
+                                          SilcBool dispatch_all)
 {
-  assert(schedule.valid != FALSE);
-  assert(fd < schedule.fd_list.max_fd);
+  SilcTask t;
+  SilcTaskTimeout task;
+  struct timeval curtime;
+  int count = 0;
+
+  SILC_LOG_DEBUG(("Running timeout tasks"));
+
+  silc_gettimeofday(&curtime);
 
-  schedule.fd_list.fd[fd] = -1;
-  
-  if (fd == schedule.fd_list.last_fd) {
-    int i;
+  /* First task in the task queue has always the earliest timeout. */
+  silc_list_start(schedule->timeout_queue);
+  while ((task = silc_list_get(schedule->timeout_queue)) != SILC_LIST_END) {
+    t = (SilcTask)task;
 
-    for (i = fd; i >= 0; i--)
-      if (schedule.fd_list.fd[i] != -1)
+    /* Remove invalid task */
+    if (!t->valid) {
+      silc_schedule_task_remove(schedule, t);
+      continue;
+    }
+
+    /* Execute the task if the timeout has expired */
+    if (dispatch_all || silc_compare_timeval(&task->timeout, &curtime)) {
+      SILC_SCHEDULE_UNLOCK(schedule);
+      t->callback(schedule, schedule->app_context, SILC_TASK_EXPIRE, 0,
+                 t->context);
+      SILC_SCHEDULE_LOCK(schedule);
+
+      /* Remove the expired task */
+      silc_schedule_task_remove(schedule, t);
+
+      /* Balance when we have lots of small timeouts */
+      if ((++count) > 50)
        break;
+    }
+  }
+}
 
-    schedule.fd_list.last_fd = i < 0 ? 0 : i;
+/* 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. */
+
+static void silc_schedule_select_timeout(SilcSchedule schedule)
+{
+  SilcTask t;
+  SilcTaskTimeout task;
+  struct timeval curtime;
+  SilcBool dispatch = TRUE;
+
+  /* Get the current time */
+  silc_gettimeofday(&curtime);
+  schedule->has_timeout = FALSE;
+
+  /* First task in the task queue has always the earliest timeout. */
+  silc_list_start(schedule->timeout_queue);
+  while ((task = silc_list_get(schedule->timeout_queue)) != SILC_LIST_END) {
+    t = (SilcTask)task;
+
+    /* Remove invalid task */
+    if (!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) && dispatch) {
+      silc_schedule_dispatch_timeout(schedule, FALSE);
+      if (!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;
+  }
+
+  /* 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));
   }
 }
 
-/* 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)
+/* Runs the scheduler once and then returns. */
 
-/* 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 */                                             \
-    gettimeofday(&curtime, NULL);                                          \
-    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; \
-                                                                           \
-          /* We wouldn't want to go under zero, check for it. */           \
-          if (queue->timeout.tv_usec < 0) {                                \
-            queue->timeout.tv_sec -= 1;                                            \
-            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"));                              \
-    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)))       \
-                 task->callback(queue, SILC_TASK_READ,                      \
-                                task->context, i);                          \
-             }                                                              \
-                                                                            \
-             if (task->valid && schedule.fd_list.fd[i] != -1) {             \
-               /* Task ready for writing */                                 \
-               if ((schedule.fd_list.fd[i] & (1L << SILC_TASK_WRITE)))      \
-                 task->callback(queue, SILC_TASK_WRITE,                     \
-                                task->context, i);                          \
-             }                                                              \
-                                                                            \
-             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)
-
-int silc_schedule_one(int timeout_usecs)
+SilcBool silc_schedule_one(SilcSchedule schedule, int timeout_usecs)
 {
   struct timeval timeout;
-  int is_run, i;
-  SilcTask task;
-  SilcTaskQueue queue;
-  struct timeval curtime;
+  int ret;
 
   SILC_LOG_DEBUG(("In scheduler loop"));
 
-  /* 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) {
+  if (!schedule->is_locked)
+    SILC_SCHEDULE_LOCK(schedule);
+
+  /* Deliver signals if any has been set to be called */
+  if (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 (schedule->valid == FALSE) {
     SILC_LOG_DEBUG(("Scheduler not valid anymore, exiting"));
+    if (!schedule->is_locked)
+      SILC_SCHEDULE_UNLOCK(schedule);
     return FALSE;
   }
 
-  /* Clear everything */
-  FD_ZERO(&schedule.in);
-  FD_ZERO(&schedule.out);
-  schedule.max_fd = -1;
-  is_run = 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);
 
-  /* Calculate next timeout for select(). This is the timeout value
-     when at earliest some of the timeout tasks expire. */
-  SILC_SCHEDULE_SELECT_TIMEOUT;
-
-  /* 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;
-
-  if (schedule.max_fd == -1 && !schedule.timeout)
+  /* Check if scheduler is valid */
+  if (schedule->valid == FALSE) {
+    SILC_LOG_DEBUG(("Scheduler not valid anymore, exiting"));
+    if (!schedule->is_locked)
+      SILC_SCHEDULE_UNLOCK(schedule);
     return FALSE;
-
-  if (schedule.timeout) {
-    SILC_LOG_DEBUG(("timeout: sec=%d, usec=%d", schedule.timeout->tv_sec,
-                   schedule.timeout->tv_usec));
   }
 
   if (timeout_usecs >= 0) {
     timeout.tv_sec = 0;
     timeout.tv_usec = timeout_usecs;
-    schedule.timeout = &timeout;
+    schedule->timeout = timeout;
+    schedule->has_timeout = TRUE;
   }
 
-  /* This is the main select(). The program blocks here until some
+  /* 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"));
-  switch (select(schedule.max_fd + 1, &schedule.in,
-                &schedule.out, 0, schedule.timeout)) {
+  ret = schedule_ops.select(schedule, schedule->internal);
+
+  switch (ret) {
+  case 0:
+    /* Timeout */
+    SILC_LOG_DEBUG(("Running timeout tasks"));
+    silc_schedule_dispatch_timeout(schedule, FALSE);
+    break;
   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"));
-    gettimeofday(&curtime, NULL);
-    SILC_SCHEDULE_RUN_TIMEOUT_TASKS;
-    break;
   default:
     /* There is some data available now */
-    SILC_LOG_DEBUG(("Running non-timeout tasks"));
-    SILC_SCHEDULE_RUN_TASKS;
-
-    SILC_SCHEDULE_RUN_GENERIC_TASKS;
+    SILC_LOG_DEBUG(("Running fd tasks"));
+    silc_schedule_dispatch_fd(schedule);
     break;
   }
+
+  if (!schedule->is_locked)
+    SILC_SCHEDULE_UNLOCK(schedule);
+
   return TRUE;
 }
 
@@ -499,16 +359,387 @@ int silc_schedule_one(int timeout_usecs)
    When this returns the program is to be ended. Before this function can
    be called, one must call silc_schedule_init function. */
 
-void silc_schedule()
+void silc_schedule(SilcSchedule schedule)
 {
   SILC_LOG_DEBUG(("Running scheduler"));
 
-  if (schedule.valid == FALSE) {
+  if (schedule->valid == FALSE) {
     SILC_LOG_ERROR(("Scheduler is not valid, stopping"));
     return;
   }
 
+  SILC_SCHEDULE_LOCK(schedule);
+  schedule->is_locked = TRUE;
+
   /* Start the scheduler loop */
-  while (silc_schedule_one(-1)) 
+  while (silc_schedule_one(schedule, -1))
     ;
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* 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
+}
+
+/* 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)
+{
+  return schedule->app_context;
+}
+
+/* Add new task to the scheduler */
+
+SilcTask silc_schedule_task_add(SilcSchedule schedule, SilcUInt32 fd,
+                               SilcTaskCallback callback, void *context,
+                               long seconds, long useconds,
+                               SilcTaskType type)
+{
+  SilcTask task = NULL;
+
+  if (!schedule->valid)
+    return NULL;
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  if (type == SILC_TASK_TIMEOUT) {
+    SilcTaskTimeout tmp, prev, ttask = silc_calloc(1, sizeof(*ttask));
+    if (!ttask)
+      goto out;
+
+    ttask->header.type = 1;
+    ttask->header.callback = callback;
+    ttask->header.context = context;
+    ttask->header.valid = TRUE;
+
+    /* Add timeout */
+    if ((seconds + useconds) > 0) {
+      silc_gettimeofday(&ttask->timeout);
+      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. */
+    silc_list_start(schedule->timeout_queue);
+    prev = NULL;
+    while ((tmp = silc_list_get(schedule->timeout_queue)) != SILC_LIST_END) {
+      /* If we have shorter timeout, we have found our spot */
+      if (silc_compare_timeval(&ttask->timeout, &tmp->timeout)) {
+       silc_list_insert(schedule->timeout_queue, prev, ttask);
+       break;
+      }
+      prev = tmp;
+    }
+    if (!tmp)
+      silc_list_add(schedule->timeout_queue, ttask);
+
+    task = (SilcTask)ttask;
+  } else {
+    /* Check if fd is already added */
+    if (silc_hash_table_find(schedule->fd_queue, SILC_32_TO_PTR(fd),
+                            NULL, (void **)&task))
+      goto out;
+
+    /* Check max tasks */
+    if (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"));
+      goto out;
+    }
+
+    SilcTaskFd ftask = silc_calloc(1, sizeof(*ftask));
+    if (!ftask)
+      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 */
+    silc_hash_table_add(schedule->fd_queue, SILC_32_TO_PTR(fd), ftask);
+
+    task = (SilcTask)ftask;
+  }
+
+ out:
+  SILC_SCHEDULE_UNLOCK(schedule);
+  return task;
+}
+
+/* Invalidates task */
+
+void silc_schedule_task_del(SilcSchedule schedule, SilcTask task)
+{
+  if (task == SILC_ALL_TASKS) {
+    SilcTask task;
+    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;
+  }
+
+  SILC_LOG_DEBUG(("Unregistering task %p", task));
+  SILC_SCHEDULE_LOCK(schedule);
+  task->valid = FALSE;
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* Invalidate task by fd */
+
+void silc_schedule_task_del_by_fd(SilcSchedule schedule, SilcUInt32 fd)
+{
+  SilcTask task;
+
+  SILC_LOG_DEBUG(("Unregister task by fd %d", fd));
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  /* fd is unique, so there is only one task with this fd in the table */
+  if (silc_hash_table_find(schedule->fd_queue, SILC_32_TO_PTR(fd), NULL,
+                          (void **)&task))
+    task->valid = FALSE;
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* Invalidate task by task callback. */
+
+void silc_schedule_task_del_by_callback(SilcSchedule schedule,
+                                       SilcTaskCallback callback)
+{
+  SilcTask task;
+  SilcHashTableList htl;
+
+  SILC_LOG_DEBUG(("Unregister task by callback"));
+
+  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->callback == callback)
+      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) {
+    if (task->callback == callback)
+      task->valid = FALSE;
+  }
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* Invalidate task by context. */
+
+void silc_schedule_task_del_by_context(SilcSchedule schedule, void *context)
+{
+  SilcTask task;
+  SilcHashTableList htl;
+
+  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;
+  }
+  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) {
+    if (task->context == context)
+      task->valid = FALSE;
+  }
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* Invalidate task by all */
+
+void silc_schedule_task_del_by_all(SilcSchedule schedule, int fd,
+                                  SilcTaskCallback callback, void *context)
+{
+  SilcTask task;
+
+  SILC_LOG_DEBUG(("Unregister task by fd, callback and context"));
+
+  /* For fd task, callback and context is irrelevant as fd is unique */
+  if (fd)
+    silc_schedule_task_del_by_fd(schedule, fd);
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  /* Delete from timeout queue */
+  silc_list_start(schedule->timeout_queue);
+  while ((task = (SilcTask)silc_list_get(schedule->timeout_queue))
+        != SILC_LIST_END) {
+    if (task->callback == callback && task->context == context)
+      task->valid = FALSE;
+  }
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* Removes task from the scheduler.  This must be called with scheduler
+   locked. */
+
+static void silc_schedule_task_remove(SilcSchedule schedule, SilcTask task)
+{
+  SilcTaskFd ftask;
+  SilcTaskTimeout ttask;
+
+  if (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 = (SilcTask)silc_list_get(schedule->timeout_queue))
+          != SILC_LIST_END) {
+      silc_list_del(schedule->timeout_queue, task);
+      silc_free(task);
+    }
+
+    return;
+  }
+
+  /* Delete from timeout queue */
+  if (task->type == 1) {
+    silc_list_start(schedule->timeout_queue);
+    while ((ttask = silc_list_get(schedule->timeout_queue)) != SILC_LIST_END) {
+      if (ttask == (SilcTaskTimeout)task) {
+       silc_list_del(schedule->timeout_queue, ttask);
+       silc_free(ttask);
+       break;
+      }
+    }
+
+    return;
+  }
+
+  /* Delete from fd queue */
+  ftask = (SilcTaskFd)task;
+  silc_hash_table_del(schedule->fd_queue, SILC_32_TO_PTR(ftask->fd));
+}
+
+/* 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_set_listen_fd(SilcSchedule schedule, SilcUInt32 fd,
+                                SilcTaskEvent mask, SilcBool send_events)
+{
+  SilcTaskFd task;
+
+  if (!schedule->valid)
+    return;
+
+  SILC_SCHEDULE_LOCK(schedule);
+
+  if (silc_hash_table_find(schedule->fd_queue, SILC_32_TO_PTR(fd),
+                          NULL, (void **)&task)) {
+    task->events = mask;
+    if (send_events) {
+      task->revents = mask;
+      silc_schedule_dispatch_fd(schedule);
+    }
+  }
+
+  SILC_SCHEDULE_UNLOCK(schedule);
+}
+
+/* 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);
+}
+
+/* Register a new signal */
+
+void silc_schedule_signal_register(SilcSchedule schedule, SilcUInt32 signal,
+                                  SilcTaskCallback callback, void *context)
+{
+  schedule_ops.signal_register(schedule, schedule->internal, signal,
+                               callback, context);
+}
+
+/* Unregister a new signal */
+
+void silc_schedule_signal_unregister(SilcSchedule schedule, SilcUInt32 signal,
+                                    SilcTaskCallback callback, void *context)
+{
+  schedule_ops.signal_unregister(schedule, schedule->internal, signal,
+                                 callback, context);
+}
+
+/* Call signal indicated by `signal'. */
+
+void silc_schedule_signal_call(SilcSchedule schedule, SilcUInt32 signal)
+{
+  /* Mark that signals needs to be delivered later. */
+  schedule_ops.signal_call(schedule, schedule->internal, signal);
+  schedule->signal_tasks = TRUE;
 }