2 * Copyright (C) 2006 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 * Short and sweet. It updates the global \a now pointer, calls all registered
69 * pre_select hooks which may set the timeout and add any file descriptors to
70 * the fd sets of \a s. Next, it calls para_select() and makes the result available
71 * to the registered tasks by calling their post_select hook.
73 * \return Zero if no more tasks are left in either of the two lists, negative
74 * if para_select returned an error.
78 int sched(struct sched *s)
81 return -E_NOT_INITIALIZED;
82 gettimeofday(now, NULL);
86 s->timeout = s->default_timeout;
89 s->select_ret = para_select(s->max_fileno + 1, &s->rfds,
90 &s->wfds, &s->timeout);
91 if (s->select_ret < 0)
93 gettimeofday(now, NULL);
95 if (list_empty(&pre_select_list) && list_empty(&post_select_list))
101 * initialize the paraslash scheduler
103 static void init_sched(void)
105 PARA_INFO_LOG("%s", "initializing scheduler\n");
106 INIT_LIST_HEAD(&pre_select_list);
107 INIT_LIST_HEAD(&post_select_list);
112 * add a task to the scheduler
114 * \param t the task to add
116 * If the pre_select pointer of \a t is not \p NULL, it is added to
117 * the pre_select list of the scheduler. Same goes for post_select.
119 * \sa task::pre_select, task::post_select
121 void register_task(struct task *t)
125 PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
127 PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);
128 list_add(&t->pre_select_node, &pre_select_list);
130 if (t->post_select) {
131 PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select);
132 list_add(&t->post_select_node, &post_select_list);
137 * remove a task from the scheduler
139 * \param t the task to remove
141 * If the pre_select pointer of \a t is not \p NULL, it is removed from
142 * the pre_select list of the scheduler. Same goes for \a post_select.
144 void unregister_task(struct task *t)
148 PARA_INFO_LOG("unregistering %s (%p)\n", t->status, t);
150 list_del(&t->pre_select_node);
152 list_del(&t->post_select_node);
156 * unregister all tasks
158 * This will cause \a sched() to return immediately because both the
159 * \a pre_select_list and the \a post_select_list are empty.
161 void sched_shutdown(void)
163 struct task *t, *tmp;
167 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
169 /* remove tasks which do not have a pre_select hook */
170 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
176 * get the list of all registered tasks.
178 * \return the task list
180 * Each entry of the list contains an identifier which is simply a hex number
181 * that may be used in \a kill_task() to terminate the task.
182 * The result ist dynamically allocated and must be freed by the caller.
184 char *get_task_list(void)
186 struct task *t, *tmp;
191 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
193 tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status);
197 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
199 // if (t->pre_select)
201 tmp_msg = make_message("%s%p\tpost\t%s\n", msg? msg : "", t, t->status);
205 //PARA_DEBUG_LOG("task list:\n%s", msg);
210 * simulate an error for the given task
212 * \param id the task identifier
214 * Find the task identified by \a id, set the tasks' return value to
215 * \p -E_TASK_KILLED and call the event handler of the task.
217 * \return Positive on success, negative on errors (e.g. if \a id does not
218 * correspond to a registered task).
220 int kill_task(char *id)
222 struct task *t, *tmp;
226 return -E_NOT_INITIALIZED;
227 list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
228 sprintf(buf, "%p", t);
231 t->ret = -E_TASK_KILLED;
232 if (t->event_handler)
236 list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
237 sprintf(buf, "%p", t);
240 t->ret = -E_TASK_KILLED;
241 if (t->event_handler)
245 return -E_NO_SUCH_TASK;