From 155f63c4f6995acff2b9c7467cfd91d1f77f3272 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex.auvolat@ens.fr>
Date: Mon, 2 Mar 2015 23:30:16 +0100
Subject: Implement process termination and cleaning up (not completely though)

---
 src/kernel/core/thread.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++--
 src/kernel/core/worker.c |  1 +
 2 files changed, 54 insertions(+), 2 deletions(-)

(limited to 'src/kernel/core')

diff --git a/src/kernel/core/thread.c b/src/kernel/core/thread.c
index 02e81e1..63523af 100644
--- a/src/kernel/core/thread.c
+++ b/src/kernel/core/thread.c
@@ -88,6 +88,21 @@ thread_t* dequeue_thread() {
 	return t;
 }
 
+void remove_thread_from_queue(thread_t *t) {
+	if (queue_first_thread == t) {
+		queue_first_thread = t->next_in_queue;
+		if (queue_first_thread == 0) queue_last_thread = 0;
+	} else {
+		for (thread_t *it = queue_first_thread; it != 0; it = it->next_in_queue) {
+			if (it->next_in_queue == t) {
+				it->next_in_queue = t->next_in_queue;
+				if (it->next_in_queue == 0) queue_last_thread = t;
+				break;
+			}
+		}
+	}
+}
+
 // ================ //
 // THE TASKING CODE //
 // ================ //
@@ -118,6 +133,9 @@ void run_scheduler() {
 static void run_thread(void (*entry)(void*), void* data) {
 	ASSERT(current_thread->state == T_STATE_RUNNING);
 
+	dbg_printf("Begin thread 0x%p (in process %d)\n",
+		current_thread, (current_thread->proc ? current_thread->proc->pid : 0));
+
 	switch_pagedir(get_kernel_pagedir());
 
 	asm volatile("sti");
@@ -166,15 +184,24 @@ thread_t *new_thread(entry_t entry, void* data) {
 	t->last_ran = 0;
 
 	t->current_pd_d = get_kernel_pagedir();
+	t->critical_level = CL_USER;
 
 	// used by user processes
 	t->proc = 0;
+	t->next_in_proc = 0;
 	t->user_ex_handler = 0;
-	t->critical_level = CL_USER;
 
 	return t;
 }
 
+static void delete_thread(thread_t *t) {
+	if (t->proc != 0)
+		process_thread_deleted(t);
+
+	region_free_unmap_free(t->stack_region->addr);
+	free(t);
+}
+
 // ========== //
 // SETUP CODE //
 // ========== //
@@ -227,8 +254,20 @@ void usleep(int usecs) {
 }
 
 void exit() {
+	void delete_thread_v(void* v) {
+		delete_thread((thread_t*)v);
+	}
+
+	int st = enter_critical(CL_NOSWITCH);
+	// the critical section here does not guarantee that worker_push will return immediately
+	// (it may switch before adding the delete_thread task), but once the task is added
+	// no other switch may happen, therefore this thread will not get re-enqueued
+
+	worker_push(delete_thread_v, current_thread);
 	current_thread->state = T_STATE_FINISHED;
-	// TODO : add job for deleting the thread, or whatever
+
+	exit_critical(st);
+
 	yield();	// expected never to return!
 	ASSERT(false);
 }
@@ -249,4 +288,16 @@ bool resume_thread(thread_t *thread) {
 	return ret;
 }
 
+void kill_thread(thread_t *thread) {
+	ASSERT(thread != current_thread);
+
+	int st = enter_critical(CL_NOSWITCH);
+
+	thread->state = T_STATE_FINISHED;
+	remove_thread_from_queue(thread);
+	delete_thread(thread);
+
+	exit_critical(st);
+}
+
 /* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/src/kernel/core/worker.c b/src/kernel/core/worker.c
index 4f37b22..e50085a 100644
--- a/src/kernel/core/worker.c
+++ b/src/kernel/core/worker.c
@@ -36,6 +36,7 @@ void start_workers(int n) {
 	nworkers = n;
 	for (int i = 0; i < n; i++) {
 		workers[i] = new_thread(worker_thread, 0);
+		dbg_printf("New worker thread: 0x%p\n", workers[i]);
 	}
 }
 
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