#include <string.h>
#include <stdlib.h>
-#include <ucontext.h>
-
-//#define CONFIG_DEBUG
#include "libthreads.h"
+#include "schedule.h"
+#include "common.h"
-#define STACK_SIZE (1024 * 1024)
+/* global "model" object */
+#include "model.h"
-static struct thread *current;
-static ucontext_t *cleanup;
+#define STACK_SIZE (1024 * 1024)
static void *stack_allocate(size_t size)
{
return malloc(size);
}
-int thread_create(struct thread *t, void (*start_routine), void *arg)
+static void stack_free(void *stack)
{
- static int created;
- ucontext_t local;
+ free(stack);
+}
- DBG();
+static int create_context(struct thread *t)
+{
+ int ret;
- t->index = created++;
- DEBUG("create thread %d\n", t->index);
+ memset(&t->context, 0, sizeof(t->context));
+ ret = getcontext(&t->context);
+ if (ret)
+ return ret;
- t->start_routine = start_routine;
- t->arg = arg;
+ /* t->start_routine == NULL means this is our initial context */
+ if (!t->start_routine)
+ return 0;
- /* Initialize state */
- getcontext(&t->context);
+ /* Initialize new managed context */
t->stack = stack_allocate(STACK_SIZE);
t->context.uc_stack.ss_sp = t->stack;
t->context.uc_stack.ss_size = STACK_SIZE;
t->context.uc_stack.ss_flags = 0;
- if (current)
- t->context.uc_link = ¤t->context;
- else
- t->context.uc_link = cleanup;
+ t->context.uc_link = &model->system_thread->context;
makecontext(&t->context, t->start_routine, 1, t->arg);
return 0;
}
-void thread_start(struct thread *t)
+static int create_initial_thread(struct thread *t)
{
- DBG();
+ memset(t, 0, sizeof(*t));
+ model->assign_id(t);
+ return create_context(t);
+}
- if (current) {
- struct thread *old = current;
- current = t;
- swapcontext(&old->context, ¤t->context);
- } else {
- current = t;
- swapcontext(cleanup, ¤t->context);
+static int thread_swap(struct thread *t1, struct thread *t2)
+{
+ return swapcontext(&t1->context, &t2->context);
+}
+
+static void thread_dispose(struct thread *t)
+{
+ DEBUG("completed thread %d\n", thread_current()->id);
+ t->state = THREAD_COMPLETED;
+ stack_free(t->stack);
+}
+
+/*
+ * Return 1 if found next thread, 0 otherwise
+ */
+static int thread_system_next(void)
+{
+ struct thread *curr, *next;
+
+ curr = thread_current();
+ if (curr) {
+ if (curr->state == THREAD_READY)
+ model->scheduler->add_thread(curr);
+ else if (curr->state == THREAD_RUNNING)
+ /* Stopped while running; i.e., completed */
+ thread_dispose(curr);
+ else
+ DEBUG("ERROR: current thread in unexpected state??\n");
}
+ next = model->scheduler->next_thread();
+ if (next)
+ next->state = THREAD_RUNNING;
+ DEBUG("(%d, %d)\n", curr ? curr->id : -1, next ? next->id : -1);
+ if (!next)
+ return 1;
+ return thread_swap(model->system_thread, next);
+}
+
+static void thread_wait_finish(void)
+{
+
DBG();
+
+ while (!thread_system_next());
}
-void a(int *idx)
+/*
+ * User program API functions
+ */
+int thread_create(struct thread *t, void (*start_routine)(), void *arg)
{
- int i;
+ int ret = 0;
+
+ DBG();
+
+ memset(t, 0, sizeof(*t));
+ model->assign_id(t);
+ DEBUG("create thread %d\n", t->id);
+
+ t->start_routine = start_routine;
+ t->arg = arg;
+
+ /* Initialize state */
+ ret = create_context(t);
+ if (ret)
+ return ret;
- for (i = 0; i < 10; i++)
- printf("Thread %d, loop %d\n", *idx, i);
+ t->state = THREAD_CREATED;
+
+ model->scheduler->add_thread(t);
+ return 0;
+}
+
+void thread_join(struct thread *t)
+{
+ while (t->state != THREAD_COMPLETED)
+ thread_yield();
}
-void user_main()
+int thread_yield(void)
{
- struct thread t1, t2;
- int i = 1, j = 2;
+ struct thread *old, *next;
- thread_create(&t1, &a, &i);
- thread_create(&t2, &a, &j);
+ DBG();
+ old = thread_current();
+ old->state = THREAD_READY;
+ next = model->system_thread;
+ return thread_swap(old, next);
+}
- printf("user_main() is going to start 2 threads\n");
- thread_start(&t1);
- thread_start(&t2);
- printf("user_main() is finished\n");
+struct thread *thread_current(void)
+{
+ return model->scheduler->get_current_thread();
}
+/*
+ * Main system function
+ */
int main()
{
- struct thread t;
- ucontext_t main_context;
+ struct thread user_thread;
+ struct thread *main_thread;
- cleanup = &main_context;
+ model = new ModelChecker();
- thread_create(&t, &user_main, NULL);
+ main_thread = (struct thread *)malloc(sizeof(*main_thread));
+ create_initial_thread(main_thread);
+ model->add_system_thread(main_thread);
- thread_start(&t);
+ /* Start user program */
+ thread_create(&user_thread, &user_main, NULL);
- DBG();
+ /* Wait for all threads to complete */
+ thread_wait_finish();
+
+ delete model;
DEBUG("Exiting\n");
return 0;