1 files changed, 131 insertions, 0 deletions
diff --git a/src/fiber.c b/src/fiber.c
new file mode 100644
index 0000000..0db2984
--- /dev/null
+++ b/src/fiber.c
@@ -0,0 +1,131 @@
+/* fiber.c - fiber management and scheduling
+ *
+ * Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ */
+#include <errno.h>
+#include <libtf/tf.h>
+#include TF_UCTX_H
+
+struct tf_scheduler {
+	struct tf_list_head	run_q;
+	struct tf_list_head	sleep_q;
+
+	struct tf_fiber *	active_fiber;
+	int			num_fibers;
+};
+
+/* FIXME: should be in thread local storage */
+static struct tf_scheduler *__scheduler;
+
+void *tf_fiber_create(tf_fiber_proc fiber_main, int private_size)
+{
+	struct tf_scheduler *sched = __scheduler;
+	struct tf_fiber *fiber;
+
+	fiber = tf_uctx_create(fiber_main, private_size);
+
+	/* The initial references for caller and scheduler */
+	*fiber = (struct tf_fiber) {
+		.ref_count = 2,
+		.queue_node = TF_LIST_INITIALIZER(fiber->queue_node),
+	};
+
+	tf_list_add_tail(&fiber->queue_node, &sched->run_q);
+	sched->num_fibers++;
+
+	return fiber->data;
+}
+
+void __tf_fiber_destroy(struct tf_fiber *fiber)
+{
+	tf_uctx_destroy(fiber);
+}
+
+void *tf_fiber_get(void *data)
+{
+	struct tf_fiber *fiber = container_of(data, struct tf_fiber, data);
+	tf_atomic_inc(fiber->ref_count);
+	return data;
+}
+
+void tf_fiber_put(void *data)
+{
+	struct tf_fiber *fiber = container_of(data, struct tf_fiber, data);
+	if (tf_atomic_dec(fiber->ref_count) == 0)
+		__tf_fiber_destroy(fiber);
+}
+
+static void run_fiber(void)
+{
+	struct tf_scheduler *sched = __scheduler;
+	struct tf_fiber *schedf = container_of((void*) __scheduler, struct tf_fiber, data);
+	struct tf_fiber *f;
+
+	if (tf_list_empty(&sched->run_q))
+		return;
+
+	f = tf_list_first(&sched->run_q, struct tf_fiber, queue_node);
+	tf_list_del(&f->queue_node);
+
+	sched->active_fiber = f;
+	switch (tf_uctx_transfer(schedf, f, 1)) {
+	case EFAULT: /* Fiber is dead */
+		tf_fiber_put(f->data);
+		sched->num_fibers--;
+		break;
+	case EAGAIN: /* Yielded, reshedule */
+		tf_list_add_tail(&f->queue_node, &sched->run_q);
+		break;
+	case EIO: /* Blocked, in sleep */
+		tf_list_add_tail(&f->queue_node, &sched->sleep_q);
+		break;
+	default:
+		TF_BUG_ON("bad scheduler call from fiber");
+	}
+}
+
+int tf_main(tf_fiber_proc main_fiber)
+{
+	struct tf_uctx *ctx = alloca(sizeof(struct tf_uctx) + sizeof(struct tf_scheduler));
+	struct tf_scheduler *sched = (struct tf_scheduler*) ctx->fiber.data;
+	int stack_guard = STACK_GUARD;
+
+	ctx->stack_guard = &stack_guard;
+	*sched = (struct tf_scheduler){
+		.run_q = TF_LIST_HEAD_INITIALIZER(sched->run_q),
+		.sleep_q = TF_LIST_HEAD_INITIALIZER(sched->sleep_q),
+	};
+	__scheduler = sched;
+	tf_fiber_put(tf_fiber_create(main_fiber, 0));
+	do {
+		run_fiber();
+	} while (likely(sched->num_fibers));
+	__scheduler = NULL;
+
+	return 0;
+}
+
+int tf_schedule(int err)
+{
+	struct tf_scheduler *sched = __scheduler;
+	struct tf_fiber *schedf = container_of((void*) __scheduler, struct tf_fiber, data);
+	struct tf_fiber *f = sched->active_fiber;
+	int r;
+
+	r = tf_uctx_transfer(f, schedf, err);
+	if (r == 1)
+		return 0;
+
+	return r;
+}
+
+void tf_kill(void *fiber)
+{
+}