Changeset 0315679 in mainline for uspace/srv/ns/task.c

Timestamp:

2009-07-06T19:40:46Z (15 years ago)

Author:

Jiri Svoboda <jirik.svoboda@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

adb49f58

Parents:

5d96851

Message:

Move fully to IPC-based tracking of task startup and termination in NS. This also gets rid of the race condition present in the previous code.

File:

• uspace/srv/ns/task.c (modified) (8 diffs)

uspace/srv/ns/task.c

@@ -49 +49 @@
 /* TODO:
  *
- * The current implementation of waiting on a task is not perfect. If somebody
- * The caller has to make sure that it is not trying to wait
- * before the NS has a change to receive the task creation notification. This
- * can be assured by waiting for this event in task_spawn().
- *
- * Finally, as there is currently no convention that each task has to be waited
+ * As there is currently no convention that each task has to be waited
  * for, the NS can leak memory because of the zombie tasks.
  *
@@ -208 +203 @@
         }
         
-        if (event_subscribe(EVENT_WAIT, 0) != EOK)
-                printf(NAME ": Error registering wait notifications\n");
-        
         list_initialize(&pending_wait);
         
@@ -248 +240 @@
 }
 
-static void fail_pending_wait(task_id_t id, int rc)
-{
-        link_t *cur;
-        
-loop:
-        for (cur = pending_wait.next; cur != &pending_wait; cur = cur->next) {
-                pending_wait_t *pr = list_get_instance(cur, pending_wait_t, link);
-                
-                if (pr->id == id) {
-                        if (!(pr->callid & IPC_CALLID_NOTIFICATION))
-                                ipc_answer_0(pr->callid, rc);
-                
-                        list_remove(cur);
-                        free(pr);
-                        goto loop;
-                }
-        }
-}
-
-void wait_notification(wait_type_t et, task_id_t id)
-{
-        unsigned long keys[2] = {
-                LOWER32(id),
-                UPPER32(id)
-        };
-        
-        link_t *link = hash_table_find(&task_hash_table, keys);
-        
-        if (link == NULL) {
-                hashed_task_t *ht =
-                    (hashed_task_t *) malloc(sizeof(hashed_task_t));
-                if (ht == NULL) {
-                        fail_pending_wait(id, ENOMEM);
-                        return;
-                }
-                
-                link_initialize(&ht->link);
-                ht->id = id;
-                ht->destroyed = (et == TASK_CREATE) ? false : true;
-                ht->retval = -1;
-                hash_table_insert(&task_hash_table, keys, &ht->link);
-        } else {
-                hashed_task_t *ht =
-                    hash_table_get_instance(link, hashed_task_t, link);
-                ht->destroyed = (et == TASK_CREATE) ? false : true;
-        }
-}
-
 void wait_for_task(task_id_t id, ipc_call_t *call, ipc_callid_t callid)
 {
@@ -309 +253 @@
 
         if (ht == NULL) {
+                /* No such task exists. */
                 retval = ENOENT;
                 goto out;
@@ -339 +284 @@
 {
         task_id_t id;
-        unsigned long keys[1];
+        unsigned long keys[2];
         link_t *link;
         p2i_entry_t *e;
+        hashed_task_t *ht;
 
         id = MERGE_LOUP32(IPC_GET_ARG1(*call), IPC_GET_ARG2(*call));
@@ -354 +300 @@
         if (e == NULL)
                 return ENOMEM;
+
+        ht = (hashed_task_t *) malloc(sizeof(hashed_task_t));
+        if (ht == NULL)
+                return ENOMEM;
+
+        /* Insert to phone-to-id map. */
 
         link_initialize(&e->link);
@@ -360 +312 @@
         hash_table_insert(&phone_to_id, keys, &e->link);
 
+        /* Insert to main table. */
+
+        keys[0] = LOWER32(id);
+        keys[1] = UPPER32(id);
+
+        link_initialize(&ht->link);
+        ht->id = id;
+        ht->destroyed = false;
+        ht->retval = -1;
+        hash_table_insert(&task_hash_table, keys, &ht->link);
+
         return EOK;
 }
@@ -390 +353 @@
 int ns_task_disconnect(ipc_call_t *call)
 {
-        unsigned long keys[1];
-
+        unsigned long keys[2];
+        task_id_t id;
+        int rc;
+
+        rc = get_id_by_phone(call->in_phone_hash, &id);
+        if (rc != EOK)
+                return rc;
+
+        /* Delete from phone-to-id map. */
         keys[0] = call->in_phone_hash;
         hash_table_remove(&phone_to_id, keys, 1);
-        
+
+        /* Mark task as finished. */
+        keys[0] = LOWER32(id);
+        keys[1] = UPPER32(id);
+
+        link_t *link = hash_table_find(&task_hash_table, keys);
+        hashed_task_t *ht =
+            hash_table_get_instance(link, hashed_task_t, link);
+        assert(ht != NULL);
+
+        ht->destroyed = true;
+
         return EOK;
 }