2 * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file sched.c paraslash's scheduling functions */
18 static struct list_head pre_select_list, post_select_list;
19 static int initialized;
21 static struct timeval now_struct;
22 struct timeval *now = &now_struct;
24 static void sched_preselect(struct sched *s)
28 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
30 // PARA_INFO_LOG("%s \n", t->status);
33 if (!t->event_handler)
40 static void sched_post_select(struct sched *s)
44 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
46 // PARA_INFO_LOG("%s: %d\n", t->status, t->ret);
47 if (t->ret > 0 || !t->event_handler)
54 * the core function for all paraslash programs
56 * \param s pointer to the scheduler struct
58 * This function updates the global \a now pointer, calls all registered
59 * pre_select hooks which may set the timeout and add any file descriptors to
60 * the fd sets of \a s. Next, it calls para_select() and makes the result available
61 * to the registered tasks by calling their post_select hook.
63 * \return Zero if no more tasks are left in either of the two lists, negative
64 * if para_select returned an error.
68 int sched(struct sched *s)
71 return -E_NOT_INITIALIZED;
72 gettimeofday(now, NULL);
76 s->timeout = s->default_timeout;
79 s->select_ret = para_select(s->max_fileno + 1, &s->rfds,
80 &s->wfds, &s->timeout);
81 if (s->select_ret < 0)
83 gettimeofday(now, NULL);
85 if (list_empty(&pre_select_list) && list_empty(&post_select_list))
91 * initialize the paraslash scheduler
93 static void init_sched(void)
95 PARA_INFO_LOG("%s", "initializing scheduler\n");
96 INIT_LIST_HEAD(&pre_select_list);
97 INIT_LIST_HEAD(&post_select_list);
102 * add a task to the scheduler
104 * \param t the task to add
106 * If the pre_select pointer of \a t is not \p NULL, it is added to
107 * the pre_select list of the scheduler. Same goes for post_select.
109 * \sa task::pre_select, task::post_select
111 void register_task(struct task *t)
115 PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
117 PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);
118 para_list_add(&t->pre_select_node, &pre_select_list);
120 if (t->post_select) {
121 PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select);
122 para_list_add(&t->post_select_node, &post_select_list);
127 * remove a task from the scheduler
129 * \param t the task to remove
131 * If the pre_select pointer of \a t is not \p NULL, it is removed from
132 * the pre_select list of the scheduler. Same goes for \a post_select.
134 void unregister_task(struct task *t)
138 PARA_INFO_LOG("unregistering %s (%p)\n", t->status, t);
140 list_del(&t->pre_select_node);
142 list_del(&t->post_select_node);
146 * unregister all tasks
148 * This will cause \a sched() to return immediately because both the
149 * \a pre_select_list and the \a post_select_list are empty.
151 void sched_shutdown(void)
153 struct task *t, *tmp;
157 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
159 /* remove tasks which do not have a pre_select hook */
160 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
166 * get the list of all registered tasks.
168 * \return the task list
170 * Each entry of the list contains an identifier which is simply a hex number
171 * that may be used in \a kill_task() to terminate the task.
172 * The result ist dynamically allocated and must be freed by the caller.
174 char *get_task_list(void)
176 struct task *t, *tmp;
181 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
183 tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status);
187 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
189 // if (t->pre_select)
191 tmp_msg = make_message("%s%p\tpost\t%s\n", msg? msg : "", t, t->status);
195 //PARA_DEBUG_LOG("task list:\n%s", msg);
200 * simulate an error for the given task
202 * \param id the task identifier
204 * Find the task identified by \a id, set the tasks' return value to
205 * \p -E_TASK_KILLED and call the event handler of the task.
207 * \return Positive on success, negative on errors (e.g. if \a id does not
208 * correspond to a registered task).
210 int kill_task(char *id)
212 struct task *t, *tmp;
216 return -E_NOT_INITIALIZED;
217 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
218 sprintf(buf, "%p", t);
221 t->ret = -E_TASK_KILLED;
222 if (t->event_handler)
226 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
227 sprintf(buf, "%p", t);
230 t->ret = -E_TASK_KILLED;
231 if (t->event_handler)
235 return -E_NO_SUCH_TASK;