+/*
+ * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file sched.c paraslash's scheduling functions */
+
#include <sys/time.h>
#include "para.h"
#include "ipc.h"
#include "string.h"
#include "error.h"
-struct list_head pre_select_list;
-struct list_head post_select_list;
+static struct list_head pre_select_list, post_select_list;
+static int initialized;
+
+static struct timeval now_struct;
+struct timeval *now = &now_struct;
static void sched_preselect(struct sched *s)
{
list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
t->post_select(s, t);
-// PARA_INFO_LOG("%s \n", t->status);
+// PARA_INFO_LOG("%s: %d\n", t->status, t->ret);
if (t->ret > 0 || !t->event_handler)
continue;
t->event_handler(t);
}
}
+/**
+ * the core function for all paraslash programs
+ *
+ * \param s pointer to the scheduler struct
+ *
+ * This function updates the global \a now pointer, calls all registered
+ * pre_select hooks which may set the timeout and add any file descriptors to
+ * the fd sets of \a s. Next, it calls para_select() and makes the result available
+ * to the registered tasks by calling their post_select hook.
+ *
+ * \return Zero if no more tasks are left in either of the two lists, negative
+ * if para_select returned an error.
+ *
+ * \sa task, now.
+ */
int sched(struct sched *s)
{
-
- gettimeofday(&s->now, NULL);
+ if (!initialized)
+ return -E_NOT_INITIALIZED;
+ gettimeofday(now, NULL);
again:
FD_ZERO(&s->rfds);
FD_ZERO(&s->wfds);
&s->wfds, &s->timeout);
if (s->select_ret < 0)
return s->select_ret;
- gettimeofday(&s->now, NULL);
+ gettimeofday(now, NULL);
sched_post_select(s);
if (list_empty(&pre_select_list) && list_empty(&post_select_list))
return 0;
goto again;
}
-void *register_task(struct task *t)
+/**
+ * initialize the paraslash scheduler
+ */
+static void init_sched(void)
{
+ PARA_INFO_LOG("%s", "initializing scheduler\n");
+ INIT_LIST_HEAD(&pre_select_list);
+ INIT_LIST_HEAD(&post_select_list);
+ initialized = 1;
+};
+
+/**
+ * add a task to the scheduler
+ *
+ * \param t the task to add
+ *
+ * If the pre_select pointer of \a t is not \p NULL, it is added to
+ * the pre_select list of the scheduler. Same goes for post_select.
+ *
+ * \sa task::pre_select, task::post_select
+ */
+void register_task(struct task *t)
+{
+ if (!initialized)
+ init_sched();
PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
if (t->pre_select) {
PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);
- if (t->flags & PRE_ADD_TAIL)
- list_add_tail(&t->pre_select_node, &pre_select_list);
- else
- list_add(&t->pre_select_node, &pre_select_list);
+ para_list_add(&t->pre_select_node, &pre_select_list);
}
if (t->post_select) {
PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select);
- if (t->flags & POST_ADD_TAIL)
- list_add_tail(&t->post_select_node, &post_select_list);
- else
- list_add(&t->post_select_node, &post_select_list);
+ para_list_add(&t->post_select_node, &post_select_list);
}
- return t;
}
+/**
+ * remove a task from the scheduler
+ *
+ * \param t the task to remove
+ *
+ * If the pre_select pointer of \a t is not \p NULL, it is removed from
+ * the pre_select list of the scheduler. Same goes for \a post_select.
+ */
void unregister_task(struct task *t)
{
+ if (!initialized)
+ return;
PARA_INFO_LOG("unregistering %s (%p)\n", t->status, t);
if (t->pre_select)
list_del(&t->pre_select_node);
list_del(&t->post_select_node);
};
-void init_sched(void)
-{
- INIT_LIST_HEAD(&pre_select_list);
- INIT_LIST_HEAD(&post_select_list);
-};
-
+/**
+ * unregister all tasks
+ *
+ * This will cause \a sched() to return immediately because both the
+ * \a pre_select_list and the \a post_select_list are empty.
+ */
void sched_shutdown(void)
{
struct task *t, *tmp;
+ if (!initialized)
+ return;
list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
unregister_task(t);
/* remove tasks which do not have a pre_select hook */
list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
unregister_task(t);
+ initialized = 0;
};
+/**
+ * get the list of all registered tasks.
+ *
+ * \return the task list
+ *
+ * Each entry of the list contains an identifier which is simply a hex number
+ * that may be used in \a kill_task() to terminate the task.
+ * The result ist dynamically allocated and must be freed by the caller.
+ */
+char *get_task_list(void)
+{
+ struct task *t, *tmp;
+ char *msg = NULL;
-//char *get_tast_list();
+ if (!initialized)
+ return NULL;
+ list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
+ char *tmp_msg;
+ tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status);
+ free(msg);
+ msg = tmp_msg;
+ }
+ list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
+ char *tmp_msg;
+// if (t->pre_select)
+// continue;
+ tmp_msg = make_message("%s%p\tpost\t%s\n", msg? msg : "", t, t->status);
+ free(msg);
+ msg = tmp_msg;
+ }
+ //PARA_DEBUG_LOG("task list:\n%s", msg);
+ return msg;
+}
+
+/**
+ * simulate an error for the given task
+ *
+ * \param id the task identifier
+ *
+ * Find the task identified by \a id, set the tasks' return value to
+ * \p -E_TASK_KILLED and call the event handler of the task.
+ *
+ * \return Positive on success, negative on errors (e.g. if \a id does not
+ * correspond to a registered task).
+ */
+int kill_task(char *id)
+{
+ struct task *t, *tmp;
+ char buf[20];
+
+ if (!initialized)
+ return -E_NOT_INITIALIZED;
+ list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
+ sprintf(buf, "%p", t);
+ if (strcmp(id, buf))
+ continue;
+ t->ret = -E_TASK_KILLED;
+ if (t->event_handler)
+ t->event_handler(t);
+ return 1;
+ }
+ list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
+ sprintf(buf, "%p", t);
+ if (strcmp(id, buf))
+ continue;
+ t->ret = -E_TASK_KILLED;
+ if (t->event_handler)
+ t->event_handler(t);
+ return 1;
+ }
+ return -E_NO_SUCH_TASK;
+}
projects / paraslash.git / blobdiff