Changeset b91bb65 in mainline

Timestamp:

2006-06-05T14:11:18Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

9c1c677

Parents:

e090e1bc

Message:

Kill task when its main thread exits.

Location:

generic

Files:

• include/proc/task.h (modified) (1 diff)
• src/proc/task.c (modified) (10 diffs)
• src/proc/thread.c (modified) (1 diff)

generic/include/proc/task.h

@@ -49 +49 @@
         
         char *name;
+        thread_t *main_thread;  /**< Pointer to the main thread. */
         link_t th_head;         /**< List of threads contained in this task. */
         as_t *as;               /**< Address space. */

generic/src/proc/task.c

@@ -59 +59 @@
 static task_id_t task_counter = 0;
 
-static void ktaskclnp(void *);
+static void ktaskclnp(void *arg);
+static void ktaskkill(void *arg);
 
 /** Initialize tasks
@@ -97 +98 @@
         ta->as = as;
         ta->name = name;
-
+        ta->main_thread = NULL;
         ta->refcount = 0;
 
@@ -154 +155 @@
         as_area_t *a;
         int rc;
-        thread_t *t;
+        thread_t *t1, *t2;
         task_t *task;
         uspace_arg_t *kernel_uarg;
@@ -184 +185 @@
                 USTACK_ADDRESS, AS_AREA_ATTR_NONE, &anon_backend, NULL);
 
-        t = thread_create(uinit, kernel_uarg, task, 0, "uinit");
-        ASSERT(t);
-        thread_ready(t);
-        
+        /*
+         * Create the main thread.
+         */
+        t1 = thread_create(uinit, kernel_uarg, task, 0, "uinit");
+        ASSERT(t1);
+        
+        /*
+         * Create killer thread for the new task.
+         */
+        t2 = thread_create(ktaskkill, t1, task, 0, "ktaskkill");
+        ASSERT(t2);
+        thread_ready(t2);
+
+        thread_ready(t1);
+
         return task;
 }
@@ -253 +265 @@
         ta->accept_new_threads = false;
         ta->refcount--;
-        
+
+        /*
+         * Interrupt all threads except this one.
+         */     
         for (cur = ta->th_head.next; cur != &ta->th_head; cur = cur->next) {
                 thread_t *thr;
@@ -318 +333 @@
 }
 
-/** Kernel thread used to cleanup the task. */
+/** Kernel thread used to cleanup the task after it is killed. */
 void ktaskclnp(void *arg)
 {
         ipl_t ipl;
-        thread_t *t = NULL;
+        thread_t *t = NULL, *main_thread;
         link_t *cur;
 
@@ -330 +345 @@
         ipl = interrupts_disable();
         spinlock_lock(&TASK->lock);
+        
+        main_thread = TASK->main_thread;
         
         /*
@@ -338 +355 @@
                 if (t == THREAD)
                         continue;
+                else if (t == main_thread)
+                        continue;
                 else
                         break;
@@ -346 +365 @@
         
         if (t != THREAD) {
+                ASSERT(t != main_thread);       /* uninit is joined and detached in ktaskkill */
                 thread_join(t);
                 thread_detach(t);
-                goto loop;
+                goto loop;      /* go for another thread */
         }
         
@@ -359 +379 @@
         futex_cleanup();
 }
+
+/** Kernel task used to kill a userspace task when its main thread exits.
+ *
+ * This thread waits until the main userspace thread (i.e. uninit) exits.
+ * When this happens, the task is killed.
+ *
+ * @param arg Pointer to the thread structure of the task's main thread.
+ */
+void ktaskkill(void *arg)
+{
+        thread_t *t = (thread_t *) arg;
+        
+        /*
+         * Userspace threads cannot detach themselves,
+         * therefore the thread pointer is guaranteed to be valid.
+         */
+        thread_join(t); /* sleep uninterruptibly here! */
+        thread_detach(t);
+        task_kill(TASK->taskid);
+}

generic/src/proc/thread.c

@@ -351 +351 @@
         }
         list_append(&t->th_link, &task->th_head);
-        task->refcount++;
+        if (task->refcount++ == 0)
+                task->main_thread = t;
         spinlock_unlock(&task->lock);