X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.c;h=2c49050cb6408085c02951b170d49d34d11169b2;hp=6b893d33c9ccb2b07c65fcb8fd02ac168d7bc6f8;hb=33713473b1051c2d9f487c66a92a5cbdf1277ce3;hpb=c075e867311c77dfb7171241597e613290d1f62b

diff --git a/sched.c b/sched.c
index 6b893d33..2c49050c 100644
--- a/sched.c
+++ b/sched.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
  *
  *     This program is free software; you can redistribute it and/or modify
  *     it under the terms of the GNU General Public License as published by
@@ -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)
@@ -71,7 +65,9 @@ static void sched_post_select(struct sched *s)
 /**
  * the core function for all paraslash programs
  *
- * Short and sweet. It updates the global \a now pointer, calls all registered
+ * \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.
@@ -83,7 +79,8 @@ 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 +99,17 @@ 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
  *
@@ -114,14 +122,16 @@ 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);
-		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);
-		list_add(&t->post_select_node, &post_select_list);
+		para_list_add(&t->post_select_node, &post_select_list);
 	}
 }
 
@@ -135,6 +145,8 @@ 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 +154,6 @@ 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 +164,14 @@ 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 +187,9 @@ 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 +216,16 @@ 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))