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/*

 * Copyright (c) 2006 Ondrej Palkovsky

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup libc

 * @{

 */

/** @file

 */

/**

 * Asynchronous library

 *

 * The aim of this library is to provide a facility for writing programs which

 * utilize the asynchronous nature of HelenOS IPC, yet using a normal way of

 * programming.

 *

 * You should be able to write very simple multithreaded programs, the async

 * framework will automatically take care of most synchronization problems.

 *

 * Default semantics:

 * - async_send_*(): Send asynchronously. If the kernel refuses to send

 *                   more messages, [ try to get responses from kernel, if

 *                   nothing found, might try synchronous ]

 *

 * Example of use (pseudo C):

 *

 * 1) Multithreaded client application

 *

 *   fibril_create(fibril1, ...);

 *   fibril_create(fibril2, ...);

 *   ...

 *

 *   int fibril1(void *arg)

 *   {

 *     conn = ipc_connect_me_to();

 *     c1 = async_send(conn);

 *     c2 = async_send(conn);

 *     async_wait_for(c1);

 *     async_wait_for(c2);

 *     ...

 *   }

 *

 *

 * 2) Multithreaded server application

 *

 *   main()

 *   {

 *     async_manager();

 *   }

 *

 *   my_client_connection(icallid, *icall)

 *   {

 *     if (want_refuse) {

 *       ipc_answer_0(icallid, ELIMIT);

 *       return;

 *     }

 *     ipc_answer_0(icallid, EOK);

 *

 *     callid = async_get_call(&call);

 *     handle_call(callid, call);

 *     ipc_answer_2(callid, 1, 2, 3);

 *

 *     callid = async_get_call(&call);

 *     ...

 *   }

 *

 */

#include <futex.h>

#include <async.h>

#include <fibril.h>

#include <stdio.h>

#include <adt/hash_table.h>

#include <adt/list.h>

#include <ipc/ipc.h>

#include <assert.h>

#include <errno.h>

#include <sys/time.h>

#include <arch/barrier.h>

#include <bool.h>

atomic_t async_futex = FUTEX_INITIALIZER;

/** Structures of this type represent a waiting fibril. */

typedef struct {

	/** Expiration time. */

	struct timeval expires;

	/** If true, this struct is in the timeout list. */

	bool inlist;

	/** Timeout list link. */

	link_t link;

	/** Identification of and link to the waiting fibril. */

	fid_t fid;

	/** If true, this fibril is currently active. */

	bool active;

	/** If true, we have timed out. */

	bool timedout;

} awaiter_t;

typedef struct {

	awaiter_t wdata;

	/** If reply was received. */

	bool done;

	/** Pointer to where the answer data is stored. */

	ipc_call_t *dataptr;

	ipcarg_t retval;

} amsg_t;

/**

 * Structures of this type are used to group information about a call and a

 * message queue link.

 */

typedef struct {

	link_t link;

	ipc_callid_t callid;

	ipc_call_t call;

} msg_t;

typedef struct {

	awaiter_t wdata;

	/** Hash table link. */

	link_t link;

	/** Incoming phone hash. */

	ipcarg_t in_phone_hash;

	/** Messages that should be delivered to this fibril. */

	link_t msg_queue;

	/** Identification of the opening call. */

	ipc_callid_t callid;

	/** Call data of the opening call. */

	ipc_call_t call;

	/** Identification of the closing call. */

	ipc_callid_t close_callid;

	/** Fibril function that will be used to handle the connection. */

	void (*cfibril)(ipc_callid_t, ipc_call_t *);

} connection_t;

/** Identifier of the incoming connection handled by the current fibril. */

__thread connection_t *FIBRIL_connection;

static void default_client_connection(ipc_callid_t callid, ipc_call_t *call);

static void default_interrupt_received(ipc_callid_t callid, ipc_call_t *call);

static void default_pending(void);

/**

 * Pointer to a fibril function that will be used to handle connections.

 */

static async_client_conn_t client_connection = default_client_connection;

/**

 * Pointer to a fibril function that will be used to handle interrupt

 * notifications.

 */

static async_client_conn_t interrupt_received = default_interrupt_received;

/**

 * Pointer to a fibril function that will be used to handle pending

 * operations.

 */

static async_pending_t pending = default_pending;

static hash_table_t conn_hash_table;

static LIST_INITIALIZE(timeout_list);

#define CONN_HASH_TABLE_CHAINS  32

/** Compute hash into the connection hash table based on the source phone hash.

 *

 * @param key Pointer to source phone hash.

 *

 * @return Index into the connection hash table.

 *

 */

static hash_index_t conn_hash(unsigned long *key)

{

	assert(key);

	return (((*key) >> 4) % CONN_HASH_TABLE_CHAINS);

}

/** Compare hash table item with a key.

 *

 * @param key  Array containing the source phone hash as the only item.

 * @param keys Expected 1 but ignored.

 * @param item Connection hash table item.

 *

 * @return True on match, false otherwise.

 *

 */

static int conn_compare(unsigned long key[], hash_count_t keys, link_t *item)

{

	connection_t *hs = hash_table_get_instance(item, connection_t, link);

	return (key[0] == hs->in_phone_hash);

}

/** Connection hash table removal callback function.

 *

 * This function is called whenever a connection is removed from the connection

 * hash table.

 *

 * @param item Connection hash table item being removed.

 *

 */

static void conn_remove(link_t *item)

{

	free(hash_table_get_instance(item, connection_t, link));

}

/** Operations for the connection hash table. */

static hash_table_operations_t conn_hash_table_ops = {

	.hash = conn_hash,

	.compare = conn_compare,

	.remove_callback = conn_remove

};

/** Sort in current fibril's timeout request.

 *

 * @param wd Wait data of the current fibril.

 *

 */

static void insert_timeout(awaiter_t *wd)

{

	wd->timedout = false;

	wd->inlist = true;

	link_t *tmp = timeout_list.next;

	while (tmp != &timeout_list) {

		awaiter_t *cur = list_get_instance(tmp, awaiter_t, link);

		if (tv_gteq(&cur->expires, &wd->expires))

			break;

		tmp = tmp->next;

	}

	list_append(&wd->link, tmp);

}

/** Try to route a call to an appropriate connection fibril.

 *

 * If the proper connection fibril is found, a message with the call is added to

 * its message queue. If the fibril was not active, it is activated and all

 * timeouts are unregistered.

 *

 * @param callid Hash of the incoming call.

 * @param call   Data of the incoming call.

 *

 * @return False if the call doesn't match any connection.

 *         True if the call was passed to the respective connection fibril.

 *

 */

static bool route_call(ipc_callid_t callid, ipc_call_t *call)

{

	futex_down(&async_futex);

	unsigned long key = call->in_phone_hash;

	link_t *hlp = hash_table_find(&conn_hash_table, &key);

	if (!hlp) {

		futex_up(&async_futex);

		return false;

	}

	connection_t *conn = hash_table_get_instance(hlp, connection_t, link);

	msg_t *msg = malloc(sizeof(*msg));

	if (!msg) {

		futex_up(&async_futex);

		return false;

	}

	msg->callid = callid;

	msg->call = *call;

	list_append(&msg->link, &conn->msg_queue);

	if (IPC_GET_METHOD(*call) == IPC_M_PHONE_HUNGUP)

		conn->close_callid = callid;

	/* If the connection fibril is waiting for an event, activate it */

	if (!conn->wdata.active) {

		/* If in timeout list, remove it */

		if (conn->wdata.inlist) {

			conn->wdata.inlist = false;

			list_remove(&conn->wdata.link);

		}

		conn->wdata.active = true;

		fibril_add_ready(conn->wdata.fid);

	}

	futex_up(&async_futex);

	return true;

}

/** Notification fibril.

 *

 * When a notification arrives, a fibril with this implementing function is

 * created. It calls interrupt_received() and does the final cleanup.

 *

 * @param arg Message structure pointer.

 *

 * @return Always zero.

 *

 */

static int notification_fibril(void *arg)

{

	msg_t *msg = (msg_t *) arg;

	interrupt_received(msg->callid, &msg->call);

	free(msg);

	return 0;

}

/** Process interrupt notification.

 *

 * A new fibril is created which would process the notification.

 *

 * @param callid Hash of the incoming call.

 * @param call   Data of the incoming call.

 *

 * @return False if an error occured.

 *         True if the call was passed to the notification fibril.

 *

 */

static bool process_notification(ipc_callid_t callid, ipc_call_t *call)

{

	futex_down(&async_futex);

	msg_t *msg = malloc(sizeof(*msg));

	if (!msg) {

		futex_up(&async_futex);

		return false;

	}

	msg->callid = callid;

	msg->call = *call;

	fid_t fid = fibril_create(notification_fibril, msg);

	fibril_add_ready(fid);

	futex_up(&async_futex);

	return true;

}

/** Pending fibril.

 *

 * After each call the pending operations are executed in a separate

 * fibril. The function pending() is c.

 *

 * @param arg Unused.

 *

 * @return Always zero.

 *

 */

static int pending_fibril(void *arg)

{

	pending();

	return 0;

}

/** Process pending actions.

 *

 * A new fibril is created which would process the pending operations.

 *

 * @return False if an error occured.

 *         True if the execution was passed to the pending fibril.

 *

 */

static bool process_pending(void)

{

	futex_down(&async_futex);

	fid_t fid = fibril_create(pending_fibril, NULL);

	fibril_add_ready(fid);

	futex_up(&async_futex);

	return true;

}

/** Return new incoming message for the current (fibril-local) connection.

 *

 * @param call  Storage where the incoming call data will be stored.

 * @param usecs Timeout in microseconds. Zero denotes no timeout.

 *

 * @return If no timeout was specified, then a hash of the

 *         incoming call is returned. If a timeout is specified,

 *         then a hash of the incoming call is returned unless

 *         the timeout expires prior to receiving a message. In

 *         that case zero is returned.

 *

 */

ipc_callid_t async_get_call_timeout(ipc_call_t *call, suseconds_t usecs)

{

	assert(FIBRIL_connection);

	/* Why doing this?

	 * GCC 4.1.0 coughs on FIBRIL_connection-> dereference.

	 * GCC 4.1.1 happilly puts the rdhwr instruction in delay slot.

	 *           I would never expect to find so many errors in

	 *           a compiler.

	 */

	connection_t *conn = FIBRIL_connection;

	futex_down(&async_futex);

	if (usecs) {

		gettimeofday(&conn->wdata.expires, NULL);

		tv_add(&conn->wdata.expires, usecs);

	} else

		conn->wdata.inlist = false;

	/* If nothing in queue, wait until something arrives */

	while (list_empty(&conn->msg_queue)) {

		if (usecs)

			insert_timeout(&conn->wdata);

		conn->wdata.active = false;

		/*

		 * Note: the current fibril will be rescheduled either due to a

		 * timeout or due to an arriving message destined to it. In the

		 * former case, handle_expired_timeouts() and, in the latter

		 * case, route_call() will perform the wakeup.

		 */

		fibril_switch(FIBRIL_TO_MANAGER);

		/*

		 * Futex is up after getting back from async_manager.

		 * Get it again.

		 */

		futex_down(&async_futex);

		if ((usecs) && (conn->wdata.timedout)

		    && (list_empty(&conn->msg_queue))) {

			/* If we timed out -> exit */

			futex_up(&async_futex);

			return 0;

		}

	}

	msg_t *msg = list_get_instance(conn->msg_queue.next, msg_t, link);

	list_remove(&msg->link);

	ipc_callid_t callid = msg->callid;

	*call = msg->call;

	free(msg);

	futex_up(&async_futex);

	return callid;

}

/** Default fibril function that gets called to handle new connection.

 *

 * This function is defined as a weak symbol - to be redefined in user code.

 *

 * @param callid Hash of the incoming call.

 * @param call   Data of the incoming call.

 *

 */

static void default_client_connection(ipc_callid_t callid, ipc_call_t *call)

{

	ipc_answer_0(callid, ENOENT);

}

/** Default fibril function that gets called to handle interrupt notifications.

 *

 * This function is defined as a weak symbol - to be redefined in user code.

 *

 * @param callid Hash of the incoming call.

 * @param call   Data of the incoming call.

 *

 */

static void default_interrupt_received(ipc_callid_t callid, ipc_call_t *call)

{

}

/** Default fibril function that gets called to handle pending operations.

 *

 * This function is defined as a weak symbol - to be redefined in user code.

 *

 */

static void default_pending(void)

{

}

/** Wrapper for client connection fibril.

 *

 * When a new connection arrives, a fibril with this implementing function is

 * created. It calls client_connection() and does the final cleanup.

 *

 * @param arg Connection structure pointer.

 *

 * @return Always zero.

 *

 */

static int connection_fibril(void *arg)

{

	/*

	 * Setup fibril-local connection pointer and call client_connection().

	 *

	 */

	FIBRIL_connection = (connection_t *) arg;

	FIBRIL_connection->cfibril(FIBRIL_connection->callid,

	    &FIBRIL_connection->call);

	/* Remove myself from the connection hash table */

	futex_down(&async_futex);

	unsigned long key = FIBRIL_connection->in_phone_hash;

	hash_table_remove(&conn_hash_table, &key, 1);

	futex_up(&async_futex);

	/* Answer all remaining messages with EHANGUP */

	while (!list_empty(&FIBRIL_connection->msg_queue)) {

		msg_t *msg

		    = list_get_instance(FIBRIL_connection->msg_queue.next, msg_t, link);

		list_remove(&msg->link);

		ipc_answer_0(msg->callid, EHANGUP);

		free(msg);

	}

	if (FIBRIL_connection->close_callid)

		ipc_answer_0(FIBRIL_connection->close_callid, EOK);

	return 0;

}

/** Create a new fibril for a new connection.

 *

 * Create new fibril for connection, fill in connection structures and inserts

 * it into the hash table, so that later we can easily do routing of messages to

 * particular fibrils.

 *

 * @param in_phone_hash Identification of the incoming connection.

 * @param callid        Hash of the opening IPC_M_CONNECT_ME_TO call.

 *                      If callid is zero, the connection was opened by

 *                      accepting the IPC_M_CONNECT_TO_ME call and this function

 *                      is called directly by the server.

 * @param call          Call data of the opening call.

 * @param cfibril       Fibril function that should be called upon opening the

 *                      connection.

 *

 * @return New fibril id or NULL on failure.

 *

 */

fid_t async_new_connection(ipcarg_t in_phone_hash, ipc_callid_t callid,

    ipc_call_t *call, void (*cfibril)(ipc_callid_t, ipc_call_t *))

{

	connection_t *conn = malloc(sizeof(*conn));

	if (!conn) {

		if (callid)

			ipc_answer_0(callid, ENOMEM);

		return NULL;

	}

	conn->in_phone_hash = in_phone_hash;

	list_initialize(&conn->msg_queue);

	conn->callid = callid;

	conn->close_callid = false;

	if (call)

		conn->call = *call;

	/* We will activate the fibril ASAP */

	conn->wdata.active = true;

	conn->cfibril = cfibril;

	conn->wdata.fid = fibril_create(connection_fibril, conn);

	if (!conn->wdata.fid) {

		free(conn);

		if (callid)

			ipc_answer_0(callid, ENOMEM);

		return NULL;

	}

	/* Add connection to the connection hash table */

	unsigned long key = conn->in_phone_hash;

	futex_down(&async_futex);

	hash_table_insert(&conn_hash_table, &key, &conn->link);

	futex_up(&async_futex);

	fibril_add_ready(conn->wdata.fid);

	return conn->wdata.fid;

}

/** Handle a call that was received.

 *

 * If the call has the IPC_M_CONNECT_ME_TO method, a new connection is created.

 * Otherwise the call is routed to its connection fibril.

 *

 * @param callid Hash of the incoming call.

 * @param call   Data of the incoming call.

 *

 */

static void handle_call(ipc_callid_t callid, ipc_call_t *call)

{

	/* Unrouted call - do some default behaviour */

	if ((callid & IPC_CALLID_NOTIFICATION)) {

		process_notification(callid, call);

		goto out;

	}

	switch (IPC_GET_METHOD(*call)) {

	case IPC_M_CONNECT_ME:

	case IPC_M_CONNECT_ME_TO:

		/* Open new connection with fibril etc. */

		async_new_connection(IPC_GET_ARG5(*call), callid, call,

		    client_connection);

		goto out;

	}

	/* Try to route the call through the connection hash table */

	if (route_call(callid, call))

		goto out;

	/* Unknown call from unknown phone - hang it up */

	ipc_answer_0(callid, EHANGUP);

	return;

out:

	process_pending();

}

/** Fire all timeouts that expired. */

static void handle_expired_timeouts(void)

{

	struct timeval tv;

	gettimeofday(&tv, NULL);

	futex_down(&async_futex);

	link_t *cur = timeout_list.next;

	while (cur != &timeout_list) {

		awaiter_t *waiter = list_get_instance(cur, awaiter_t, link);

		if (tv_gt(&waiter->expires, &tv))

			break;

		cur = cur->next;

		list_remove(&waiter->link);

		waiter->inlist = false;

		waiter->timedout = true;

		/*

		 * Redundant condition?

		 * The fibril should not be active when it gets here.

		 */

		if (!waiter->active) {

			waiter->active = true;

			fibril_add_ready(waiter->fid);

		}

	}

	futex_up(&async_futex);

}

/** Endless loop dispatching incoming calls and answers.

 *

 * @return Never returns.

 *

 */

static int async_manager_worker(void)

{

	while (true) {

		if (fibril_switch(FIBRIL_FROM_MANAGER)) {

			futex_up(&async_futex); 

			/*

			 * async_futex is always held when entering a manager

			 * fibril.

			 */

			continue;

		}

		futex_down(&async_futex);

		suseconds_t timeout;

		if (!list_empty(&timeout_list)) {

			awaiter_t *waiter

			    = list_get_instance(timeout_list.next, awaiter_t, link);

			struct timeval tv;

			gettimeofday(&tv, NULL);

			if (tv_gteq(&tv, &waiter->expires)) {

				futex_up(&async_futex);

				handle_expired_timeouts();

				continue;

			} else

				timeout = tv_sub(&waiter->expires, &tv);

		} else

			timeout = SYNCH_NO_TIMEOUT;

		futex_up(&async_futex);

		ipc_call_t call;

		ipc_callid_t callid

		    = ipc_wait_cycle(&call, timeout, SYNCH_FLAGS_NONE);

		if (!callid) {

			handle_expired_timeouts();

			continue;

		}

		if (callid & IPC_CALLID_ANSWERED)

			continue;

		handle_call(callid, &call);

	}

	return 0;

}

/** Function to start async_manager as a standalone fibril.

 *

 * When more kernel threads are used, one async manager should exist per thread.

 *

 * @param arg Unused.

 * @return Never returns.

 *

 */

static int async_manager_fibril(void *arg)

{

	futex_up(&async_futex);

	/*

	 * async_futex is always locked when entering manager

	 */

	async_manager_worker();

	return 0;

}

/** Add one manager to manager list. */

void async_create_manager(void)

{

	fid_t fid = fibril_create(async_manager_fibril, NULL);

	fibril_add_manager(fid);

}

/** Remove one manager from manager list */

void async_destroy_manager(void)

{

	fibril_remove_manager();

}

/** Initialize the async framework.

 *

 * @return Zero on success or an error code.

 */

int _async_init(void)

{

	if (!hash_table_create(&conn_hash_table, CONN_HASH_TABLE_CHAINS, 1,

	    &conn_hash_table_ops)) {

		printf("%s: cannot create hash table\n", "async");

		return ENOMEM;

	}

	return 0;

}

/** Reply received callback.

 *

 * This function is called whenever a reply for an asynchronous message sent out

 * by the asynchronous framework is received.

 *

 * Notify the fibril which is waiting for this message that it has arrived.

 *

 * @param arg    Pointer to the asynchronous message record.

 * @param retval Value returned in the answer.

 * @param data   Call data of the answer.

 */

static void reply_received(void *arg, int retval, ipc_call_t *data)

{

	futex_down(&async_futex);

	amsg_t *msg = (amsg_t *) arg;

	msg->retval = retval;

	/* Copy data after futex_down, just in case the call was detached */

	if ((msg->dataptr) && (data))

		*msg->dataptr = *data;

	write_barrier();

	/* Remove message from timeout list */

	if (msg->wdata.inlist)

		list_remove(&msg->wdata.link);

	msg->done = true;

	if (!msg->wdata.active) {

		msg->wdata.active = true;

		fibril_add_ready(msg->wdata.fid);

	}

	futex_up(&async_futex);

}

/** Send message and return id of the sent message.

 *

 * The return value can be used as input for async_wait() to wait for

 * completion.

 *

 * @param phoneid Handle of the phone that will be used for the send.

 * @param method  Service-defined method.

 * @param arg1    Service-defined payload argument.

 * @param arg2    Service-defined payload argument.

 * @param arg3    Service-defined payload argument.

 * @param arg4    Service-defined payload argument.

 * @param dataptr If non-NULL, storage where the reply data will be

 *                stored.

 *

 * @return Hash of the sent message or 0 on error.

 *

 */

aid_t async_send_fast(int phoneid, ipcarg_t method, ipcarg_t arg1,

    ipcarg_t arg2, ipcarg_t arg3, ipcarg_t arg4, ipc_call_t *dataptr)

{

	amsg_t *msg = malloc(sizeof(*msg));

	if (!msg)

		return 0;

	msg->done = false;

	msg->dataptr = dataptr;

	msg->wdata.inlist = false;

	/* We may sleep in the next method, but it will use its own mechanism */

	msg->wdata.active = true;

	ipc_call_async_4(phoneid, method, arg1, arg2, arg3, arg4, msg,

	    reply_received, true);

	return (aid_t) msg;

}

/** Send message and return id of the sent message

 *

 * The return value can be used as input for async_wait() to wait for

 * completion.

 *

 * @param phoneid Handle of the phone that will be used for the send.

 * @param method  Service-defined method.

 * @param arg1    Service-defined payload argument.

 * @param arg2    Service-defined payload argument.

 * @param arg3    Service-defined payload argument.

 * @param arg4    Service-defined payload argument.

 * @param arg5    Service-defined payload argument.

 * @param dataptr If non-NULL, storage where the reply data will be

 *                stored.

 *

 * @return Hash of the sent message or 0 on error.

 *

 */

aid_t async_send_slow(int phoneid, ipcarg_t method, ipcarg_t arg1,

    ipcarg_t arg2, ipcarg_t arg3, ipcarg_t arg4, ipcarg_t arg5,

    ipc_call_t *dataptr)

{

	amsg_t *msg = malloc(sizeof(*msg));

	if (!msg)

		return 0;

	msg->done = false;

	msg->dataptr = dataptr;

	msg->wdata.inlist = false;

	/* We may sleep in next method, but it will use its own mechanism */

	msg->wdata.active = true;

	ipc_call_async_5(phoneid, method, arg1, arg2, arg3, arg4, arg5, msg,

	    reply_received, true);

	return (aid_t) msg;

}

/** Wait for a message sent by the async framework.

 *

 * @param amsgid Hash of the message to wait for.

 * @param retval Pointer to storage where the retval of the answer will

 *               be stored.

 *

 */

void async_wait_for(aid_t amsgid, ipcarg_t *retval)

{

	amsg_t *msg = (amsg_t *) amsgid;

	futex_down(&async_futex);

	if (msg->done) {

		futex_up(&async_futex);

		goto done;

	}

	msg->wdata.fid = fibril_get_id();

	msg->wdata.active = false;

	msg->wdata.inlist = false;

	/* Leave the async_futex locked when entering this function */

	fibril_switch(FIBRIL_TO_MANAGER);

	/* Futex is up automatically after fibril_switch */

done:

	if (retval)

		*retval = msg->retval;

	free(msg);

}

/** Wait for a message sent by the async framework, timeout variant.

 *

 * @param amsgid  Hash of the message to wait for.

 * @param retval  Pointer to storage where the retval of the answer will

 *                be stored.

 * @param timeout Timeout in microseconds.

 *

 * @return Zero on success, ETIMEOUT if the timeout has expired.

 *

 */

int async_wait_timeout(aid_t amsgid, ipcarg_t *retval, suseconds_t timeout)

{

	amsg_t *msg = (amsg_t *) amsgid;

	/* TODO: Let it go through the event read at least once */

	if (timeout < 0)

		return ETIMEOUT;

	futex_down(&async_futex);

	if (msg->done) {

		futex_up(&async_futex);

		goto done;

	}

	gettimeofday(&msg->wdata.expires, NULL);

	tv_add(&msg->wdata.expires, timeout);

	msg->wdata.fid = fibril_get_id();

	msg->wdata.active = false;

	insert_timeout(&msg->wdata);

	/* Leave the async_futex locked when entering this function */

	fibril_switch(FIBRIL_TO_MANAGER);

	/* Futex is up automatically after fibril_switch */

	if (!msg->done)

		return ETIMEOUT;

done:

	if (retval)

		*retval = msg->retval;

	free(msg);

	return 0;

}

/** Wait for specified time.

 *

 * The current fibril is suspended but the thread continues to execute.

 *

 * @param timeout Duration of the wait in microseconds.

 *

 */

void async_usleep(suseconds_t timeout)

{

	amsg_t *msg = malloc(sizeof(*msg));

	if (!msg)

		return;

	msg->wdata.fid = fibril_get_id();

	msg->wdata.active = false;

	gettimeofday(&msg->wdata.expires, NULL);

	tv_add(&msg->wdata.expires, timeout);

	futex_down(&async_futex);

	insert_timeout(&msg->wdata);

	/* Leave the async_futex locked when entering this function */

	fibril_switch(FIBRIL_TO_MANAGER);

	/* Futex is up automatically after fibril_switch() */

	free(msg);

}

/** Setter for client_connection function pointer.

 *

 * @param conn Function that will implement a new connection fibril.

 *

 */

void async_set_client_connection(async_client_conn_t conn)

{

	client_connection = conn;

}

/** Setter for interrupt_received function pointer.

 *

 * @param intr Function that will implement a new interrupt

 *             notification fibril.

 */

void async_set_interrupt_received(async_client_conn_t intr)

{