X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.c;h=c2a0e64b16326c5ce4f28b20cb4a048ae6322d30;hp=6b893d33c9ccb2b07c65fcb8fd02ac168d7bc6f8;hb=b3fd38bd1965ca8fec37cdd94552dc0f62f41372;hpb=c075e867311c77dfb7171241597e613290d1f62b

diff --git a/sched.c b/sched.c
index 6b893d33..c2a0e64b 100644
--- a/sched.c
+++ b/sched.c
@@ -27,16 +27,10 @@
 #include "string.h"
 #include "error.h"
 
-/**
- * The scheduler manages two lists of tasks.  The pre_select list contains
- * pointers to functions that are called before calling select() from the main
- * loop. Similarly, \a post_select_list is a list of function pointers each of
- * which is called after the select call.
- */
-struct list_head pre_select_list, 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)
@@ -83,7 +77,8 @@ static void sched_post_select(struct sched *s)
  */
 int sched(struct sched *s)
 {
-
+	if (!initialized)
+		return -E_NOT_INITIALIZED;
 	gettimeofday(now, NULL);
 again:
 	FD_ZERO(&s->rfds);
@@ -102,6 +97,17 @@ again:
 	goto again;
 }
 
+/**
+ * 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
  *
@@ -114,6 +120,8 @@ again:
  */
 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);
@@ -135,6 +143,8 @@ void register_task(struct task *t)
  */
 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);
@@ -142,15 +152,6 @@ void unregister_task(struct task *t)
 		list_del(&t->post_select_node);
 };
 
-/**
- * initialize the paraslash scheduler
- */
-void init_sched(void)
-{
-	INIT_LIST_HEAD(&pre_select_list);
-	INIT_LIST_HEAD(&post_select_list);
-};
-
 /**
  * unregister all tasks
  *
@@ -161,11 +162,14 @@ 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;
 };
 
 /**
@@ -181,6 +185,9 @@ char *get_task_list(void)
 {
 	struct task *t, *tmp;
 	char *msg = NULL;
+
+	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);
@@ -207,13 +214,16 @@ char *get_task_list(void)
  * 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 sucess, negative if \a id does not correspond to a
- * registered 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))