kern/{task,thread}: add the task_info and thread_trace shell commands

1 files changed, 42 insertions, 0 deletions

diff --git a/kern/task.h b/kern/task.h
index 67599399..cfe694bf 100644
--- a/kern/task.h
+++ b/kern/task.h
@@ -18,6 +18,7 @@
 #ifndef _KERN_TASK_H
 #define _KERN_TASK_H
 
+#include <kern/atomic.h>
 #include <kern/list.h>
 #include <kern/spinlock.h>
 #include <kern/thread.h>
@@ -32,6 +33,7 @@
  * Task structure.
  */
 struct task {
+    unsigned long nr_refs;
     struct spinlock lock;
     struct list node;
     struct list threads;
@@ -44,6 +46,28 @@ struct task {
  */
 extern struct task *kernel_task;
 
+static inline void
+task_ref(struct task *task)
+{
+    unsigned long nr_refs;
+
+    nr_refs = atomic_fetch_add(&task->nr_refs, 1, ATOMIC_RELAXED);
+    assert(nr_refs != (unsigned long)-1);
+}
+
+static inline void
+task_unref(struct task *task)
+{
+    unsigned long nr_refs;
+
+    nr_refs = atomic_fetch_sub_acq_rel(&task->nr_refs, 1);
+    assert(nr_refs != 0);
+
+    if (nr_refs == 1) {
+        /* TODO Task destruction */
+    }
+}
+
 /*
  * Initialize the task module.
  */
@@ -55,6 +79,15 @@ void task_setup(void);
 int task_create(struct task **taskp, const char *name);
 
 /*
+ * Look up a task from its name.
+ *
+ * If a task is found, it gains a reference. Otherwise, NULL is returned.
+ *
+ * This function is meant for debugging only.
+ */
+struct task * task_lookup(const char *name);
+
+/*
  * Add a thread to a task.
  */
 void task_add_thread(struct task *task, struct thread *thread);
@@ -65,6 +98,15 @@ void task_add_thread(struct task *task, struct thread *thread);
 void task_remove_thread(struct task *task, struct thread *thread);
 
 /*
+ * Look up a thread in a task from its name.
+ *
+ * If a thread is found, it gains a reference, Otherwise, NULL is returned.
+ *
+ * This function is meant for debugging only.
+ */
+struct thread * task_lookup_thread(struct task *task, const char *name);
+
+/*
  * Display task information.
  *
  * If task is NULL, this function displays all tasks.