2 * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
19 /** \file sched.c paraslash's scheduling functions */
30 static struct list_head pre_select_list, post_select_list;
31 static int initialized;
33 static struct timeval now_struct;
34 struct timeval *now = &now_struct;
36 static void sched_preselect(struct sched *s)
40 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
42 // PARA_INFO_LOG("%s \n", t->status);
45 if (!t->event_handler)
52 static void sched_post_select(struct sched *s)
56 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
58 // PARA_INFO_LOG("%s: %d\n", t->status, t->ret);
59 if (t->ret > 0 || !t->event_handler)
66 * the core function for all paraslash programs
68 * \param s pointer to the scheduler struct
70 * This function updates the global \a now pointer, calls all registered
71 * pre_select hooks which may set the timeout and add any file descriptors to
72 * the fd sets of \a s. Next, it calls para_select() and makes the result available
73 * to the registered tasks by calling their post_select hook.
75 * \return Zero if no more tasks are left in either of the two lists, negative
76 * if para_select returned an error.
80 int sched(struct sched *s)
83 return -E_NOT_INITIALIZED;
84 gettimeofday(now, NULL);
88 s->timeout = s->default_timeout;
91 s->select_ret = para_select(s->max_fileno + 1, &s->rfds,
92 &s->wfds, &s->timeout);
93 if (s->select_ret < 0)
95 gettimeofday(now, NULL);
97 if (list_empty(&pre_select_list) && list_empty(&post_select_list))
103 * initialize the paraslash scheduler
105 static void init_sched(void)
107 PARA_INFO_LOG("%s", "initializing scheduler\n");
108 INIT_LIST_HEAD(&pre_select_list);
109 INIT_LIST_HEAD(&post_select_list);
114 * add a task to the scheduler
116 * \param t the task to add
118 * If the pre_select pointer of \a t is not \p NULL, it is added to
119 * the pre_select list of the scheduler. Same goes for post_select.
121 * \sa task::pre_select, task::post_select
123 void register_task(struct task *t)
127 PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
129 PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);
130 para_list_add(&t->pre_select_node, &pre_select_list);
132 if (t->post_select) {
133 PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select);
134 para_list_add(&t->post_select_node, &post_select_list);
139 * remove a task from the scheduler
141 * \param t the task to remove
143 * If the pre_select pointer of \a t is not \p NULL, it is removed from
144 * the pre_select list of the scheduler. Same goes for \a post_select.
146 void unregister_task(struct task *t)
150 PARA_INFO_LOG("unregistering %s (%p)\n", t->status, t);
152 list_del(&t->pre_select_node);
154 list_del(&t->post_select_node);
158 * unregister all tasks
160 * This will cause \a sched() to return immediately because both the
161 * \a pre_select_list and the \a post_select_list are empty.
163 void sched_shutdown(void)
165 struct task *t, *tmp;
169 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
171 /* remove tasks which do not have a pre_select hook */
172 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
178 * get the list of all registered tasks.
180 * \return the task list
182 * Each entry of the list contains an identifier which is simply a hex number
183 * that may be used in \a kill_task() to terminate the task.
184 * The result ist dynamically allocated and must be freed by the caller.
186 char *get_task_list(void)
188 struct task *t, *tmp;
193 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
195 tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status);
199 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
201 // if (t->pre_select)
203 tmp_msg = make_message("%s%p\tpost\t%s\n", msg? msg : "", t, t->status);
207 //PARA_DEBUG_LOG("task list:\n%s", msg);
212 * simulate an error for the given task
214 * \param id the task identifier
216 * Find the task identified by \a id, set the tasks' return value to
217 * \p -E_TASK_KILLED and call the event handler of the task.
219 * \return Positive on success, negative on errors (e.g. if \a id does not
220 * correspond to a registered task).
222 int kill_task(char *id)
224 struct task *t, *tmp;
228 return -E_NOT_INITIALIZED;
229 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
230 sprintf(buf, "%p", t);
233 t->ret = -E_TASK_KILLED;
234 if (t->event_handler)
238 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
239 sprintf(buf, "%p", t);
242 t->ret = -E_TASK_KILLED;
243 if (t->event_handler)
247 return -E_NO_SUCH_TASK;