/*
* 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 facilitating writing programs utilizing 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_fast(icallid, ELIMIT, 0, 0);
* return;
* }
* ipc_answer_fast(icallid, EOK, 0, 0);
*
* callid = async_get_call(&call);
* handle_call(callid, call);
* ipc_answer_fast(callid, 1, 2, 3);
*
* callid = async_get_call(&call);
* ....
* }
*
*/
#include <futex.h>
#include <async.h>
#include <fibril.h>
#include <stdio.h>
#include <libadt/hash_table.h>
#include <libadt/list.h>
#include <ipc/ipc.h>
#include <assert.h>
#include <errno.h>
#include <sys/time.h>
#include <arch/barrier.h>
atomic_t async_futex = FUTEX_INITIALIZER;
static hash_table_t conn_hash_table;
static LIST_INITIALIZE(timeout_list);
/** Structures of this type represent a waiting fibril. */
typedef struct {
/** Expiration time. */
struct timeval expires;
/** If true, this struct is in the timeout list. */
int 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. */
int active;
/** If true, we have timed out. */
int timedout;
} awaiter_t;
typedef struct {
awaiter_t wdata;
/** If reply was received. */
int 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;
/**
* If true, it is forbidden to use async_req functions and all preemption is
* disabled.
*/
__thread int in_interrupt_handler;
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);
/**
* 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;
#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)
{
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;
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)
{
link_t *tmp;
awaiter_t *cur;
wd->timedout = 0;
wd->inlist = 1;
tmp = timeout_list.next;
while (tmp != &timeout_list) {
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 Zero if the call doesn't match any connection.
* One if the call was passed to the respective connection
* fibril.
*/
static int route_call(ipc_callid_t callid, ipc_call_t *call)
{
connection_t *conn;
msg_t *msg;
link_t *hlp;
unsigned long key;
futex_down(&async_futex);
key = call->in_phone_hash;
hlp = hash_table_find(&conn_hash_table, &key);
if (!hlp) {
futex_up(&async_futex);
return 0;
}
conn = hash_table_get_instance(hlp, connection_t, link);
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 = 0;
list_remove(&conn->wdata.link);
}
conn->wdata.active = 1;
fibril_add_ready(conn->wdata.fid);
}
futex_up(&async_futex);
return 1;
}
/** 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)
{
msg_t *msg;
ipc_callid_t callid;
connection_t *conn;
/* 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 *($&$(*&$
*/
conn = FIBRIL_connection;
futex_down(&async_futex);
if (usecs) {
gettimeofday(&conn->wdata.expires, NULL);
tv_add(&conn->wdata.expires, usecs);
} else {
conn->wdata.inlist = 0;
}
/* If nothing in queue, wait until something arrives */
while (list_empty(&conn->msg_queue)) {
if (usecs)
insert_timeout(&conn->wdata);
conn->wdata.active = 0;
/*
* 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_schedule_next_adv(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 = list_get_instance(conn->msg_queue.next, msg_t, link);
list_remove(&msg->link);
callid = msg->callid;
*call = msg->call;
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_fast(callid, ENOENT, 0, 0);
}
/** Default fibril function that gets called to handle interrupt notifications.
*
* @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)
{
}
/** 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)
{
unsigned long key;
msg_t *msg;
int close_answered = 0;
/* Setup fibril-local connection pointer */
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);
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 = list_get_instance(FIBRIL_connection->msg_queue.next,
msg_t, link);
list_remove(&msg->link);
if (msg->callid == FIBRIL_connection->close_callid)
close_answered = 1;
ipc_answer_fast(msg->callid, EHANGUP, 0, 0);
}
if (FIBRIL_connection->close_callid)
ipc_answer_fast(FIBRIL_connection->close_callid, 0, 0, 0);
return 0;
}
/** Create a new fibril for a new connection.
*
* Creates new fibril for connection, fills 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;
unsigned long key;
if (!conn) {
if (callid)
ipc_answer_fast(callid, ENOMEM, 0, 0);
return NULL;
}
conn->in_phone_hash = in_phone_hash;
list_initialize(&conn->msg_queue);
conn->callid = callid;
conn->close_callid = 0;
if (call)
conn->call = *call;
conn->wdata.active = 1; /* We will activate the fibril ASAP */
conn->cfibril = cfibril;
conn->wdata.fid = fibril_create(connection_fibril, conn);
if (!conn->wdata.fid) {
if (callid)
ipc_answer_fast(callid, ENOMEM, 0, 0);
return NULL;
}
/* Add connection to the connection hash table */
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)) {
in_interrupt_handler = 1;
(*interrupt_received)(callid,call);
in_interrupt_handler = 0;
return;
}
switch (IPC_GET_METHOD(*call)) {
case IPC_M_CONNECT_ME_TO:
/* Open new connection with fibril etc. */
async_new_connection(IPC_GET_ARG3(*call), callid, call,
client_connection);
return;
}
/* Try to route the call through the connection hash table */
if (route_call(callid, call))
return;
/* Unknown call from unknown phone - hang it up */
ipc_answer_fast(callid, EHANGUP, 0, 0);
}
/** Fire all timeouts that expired. */
static void handle_expired_timeouts(void)
{
struct timeval tv;
awaiter_t *waiter;
link_t *cur;
gettimeofday(&tv, NULL);
futex_down(&async_futex);
cur = timeout_list.next;
while (cur != &timeout_list) {
waiter = list_get_instance(cur, awaiter_t, link);
if (tv_gt(&waiter->expires, &tv))
break;
cur = cur->next;
list_remove(&waiter->link);
waiter->inlist = 0;
waiter->timedout = 1;
/*
* Redundant condition?
* The fibril should not be active when it gets here.
*/
if (!waiter->active) {
waiter->active = 1;
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)
{
ipc_call_t call;
ipc_callid_t callid;
int timeout;
awaiter_t *waiter;
struct timeval tv;
while (1) {
if (fibril_schedule_next_adv(FIBRIL_FROM_MANAGER)) {
futex_up(&async_futex);
/*
* async_futex is always held when entering a manager
* fibril.
*/
continue;
}
futex_down(&async_futex);
if (!list_empty(&timeout_list)) {
waiter = list_get_instance(timeout_list.next, awaiter_t,
link);
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);
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;
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 private 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 *private, int retval, ipc_call_t *data)
{
amsg_t *msg = (amsg_t *) private;
msg->retval = retval;
futex_down(&async_futex);
/* Copy data after futex_down, just in case the call was detached */
if (msg->dataptr)
*msg->dataptr = *data;
write_barrier();
/* Remove message from timeout list */
if (msg->wdata.inlist)
list_remove(&msg->wdata.link);
msg->done = 1;
if (!msg->wdata.active) {
msg->wdata.active = 1;
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 dataptr If non-NULL, storage where the reply data will be
* stored.
*
* @return Hash of the sent message.
*/
aid_t async_send_2(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,
ipc_call_t *dataptr)
{
amsg_t *msg;
if (in_interrupt_handler) {
printf("Cannot send asynchronous request in interrupt " "handler.\n");
_exit(1);
}
msg->done = 0;
msg->dataptr = dataptr;
/* We may sleep in the next method, but it will use its own mechanism */
msg->wdata.active = 1;
ipc_call_async_2(phoneid, method, arg1, arg2, msg, reply_received, 1);
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 dataptr If non-NULL, storage where the reply data will be
* stored.
*
* @return Hash of the sent message.
*/
aid_t async_send_3(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,
ipcarg_t arg3, ipc_call_t *dataptr)
{
amsg_t *msg;
if (in_interrupt_handler) {
printf("Cannot send asynchronous request in interrupt " "handler.\n");
_exit(1);
}
msg->done = 0;
msg->dataptr = dataptr;
/* We may sleep in next method, but it will use its own mechanism */
msg->wdata.active = 1;
ipc_call_async_3(phoneid, method, arg1, arg2, arg3, msg, reply_received,
1);
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 = 0;
msg->wdata.inlist = 0;
/* Leave the async_futex locked when entering this function */
fibril_schedule_next_adv(FIBRIL_TO_MANAGER);
/* futex is up automatically after fibril_schedule_next...*/
done:
if (retval)
*retval = msg->retval;
}
/** 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 = 0;
insert_timeout(&msg->wdata);
/* Leave the async_futex locked when entering this function */
fibril_schedule_next_adv(FIBRIL_TO_MANAGER);
/* futex is up automatically after fibril_schedule_next...*/
if (!msg->done)
return ETIMEOUT;
done:
if (retval)
*retval = msg->retval;
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;
if (in_interrupt_handler) {
printf("Cannot call async_usleep in interrupt handler.\n"); _exit(1);
}
if (!msg)
return;
msg->wdata.fid = fibril_get_id();
msg->wdata.active = 0;
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_schedule_next_adv(FIBRIL_TO_MANAGER);
/* futex is up automatically after fibril_schedule_next_adv()...*/
}
/** 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 conn Function that will implement a new interrupt
* notification fibril.
*/
void async_set_interrupt_received(async_client_conn_t conn)
{
interrupt_received = conn;
}
/* Primitive functions for simple communication */
void async_msg_3(int phoneid, ipcarg_t method, ipcarg_t arg1,
ipcarg_t arg2, ipcarg_t arg3)
{
ipc_call_async_3(phoneid, method, arg1, arg2, arg3, NULL, NULL,
!in_interrupt_handler);
}
void async_msg_2(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2)
{
ipc_call_async_2(phoneid, method, arg1, arg2, NULL, NULL,
!in_interrupt_handler);
}
/** @}
*/