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 */
9 #include <dirent.h> /* readdir() */
21 static struct list_head pre_select_list, post_select_list;
22 static int initialized;
24 static struct timeval now_struct;
25 struct timeval *now = &now_struct;
27 static void sched_preselect(struct sched *s)
31 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
33 // PARA_INFO_LOG("%s \n", t->status);
36 if (!t->event_handler)
43 static void sched_post_select(struct sched *s)
47 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
49 // PARA_INFO_LOG("%s: %d\n", t->status, t->ret);
50 if (t->ret > 0 || !t->event_handler)
57 * the core function for all paraslash programs
59 * \param s pointer to the scheduler struct
61 * This function updates the global \a now pointer, calls all registered
62 * pre_select hooks which may set the timeout and add any file descriptors to
63 * the fd sets of \a s. Next, it calls para_select() and makes the result available
64 * to the registered tasks by calling their post_select hook.
66 * \return Zero if no more tasks are left in either of the two lists, negative
67 * if para_select returned an error.
71 int schedule(struct sched *s)
74 return -E_NOT_INITIALIZED;
75 gettimeofday(now, NULL);
79 s->timeout = s->default_timeout;
82 s->select_ret = para_select(s->max_fileno + 1, &s->rfds,
83 &s->wfds, &s->timeout);
84 if (s->select_ret < 0)
86 gettimeofday(now, NULL);
88 if (list_empty(&pre_select_list) && list_empty(&post_select_list))
94 * initialize the paraslash scheduler
96 static void init_sched(void)
98 PARA_INFO_LOG("%s", "initializing scheduler\n");
99 INIT_LIST_HEAD(&pre_select_list);
100 INIT_LIST_HEAD(&post_select_list);
105 * add a task to the scheduler
107 * \param t the task to add
109 * If the pre_select pointer of \a t is not \p NULL, it is added to
110 * the pre_select list of the scheduler. Same goes for post_select.
112 * \sa task::pre_select, task::post_select
114 void register_task(struct task *t)
118 PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
120 PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);
121 para_list_add(&t->pre_select_node, &pre_select_list);
123 if (t->post_select) {
124 PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select);
125 para_list_add(&t->post_select_node, &post_select_list);
130 * remove a task from the scheduler
132 * \param t the task to remove
134 * If the pre_select pointer of \a t is not \p NULL, it is removed from
135 * the pre_select list of the scheduler. Same goes for \a post_select.
137 void unregister_task(struct task *t)
141 PARA_INFO_LOG("unregistering %s (%p)\n", t->status, t);
143 list_del(&t->pre_select_node);
145 list_del(&t->post_select_node);
149 * unregister all tasks
151 * This will cause \a schedule() to return immediately because both the
152 * \a pre_select_list and the \a post_select_list are empty.
154 void sched_shutdown(void)
156 struct task *t, *tmp;
160 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
162 /* remove tasks which do not have a pre_select hook */
163 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
169 * get the list of all registered tasks.
171 * \return the task list
173 * Each entry of the list contains an identifier which is simply a hex number
174 * that may be used in \a kill_task() to terminate the task.
175 * The result ist dynamically allocated and must be freed by the caller.
177 char *get_task_list(void)
179 struct task *t, *tmp;
184 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
186 tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status);
190 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
192 // if (t->pre_select)
194 tmp_msg = make_message("%s%p\tpost\t%s\n", msg? msg : "", t, t->status);
198 //PARA_DEBUG_LOG("task list:\n%s", msg);
203 * simulate an error for the given task
205 * \param id the task identifier
207 * Find the task identified by \a id, set the tasks' return value to
208 * \p -E_TASK_KILLED and call the event handler of the task.
210 * \return Positive on success, negative on errors (e.g. if \a id does not
211 * correspond to a registered task).
213 int kill_task(char *id)
215 struct task *t, *tmp;
219 return -E_NOT_INITIALIZED;
220 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
221 sprintf(buf, "%p", t);
224 t->ret = -E_TASK_KILLED;
225 if (t->event_handler)
229 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
230 sprintf(buf, "%p", t);
233 t->ret = -E_TASK_KILLED;
234 if (t->event_handler)
238 return -E_NO_SUCH_TASK;