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  1. /*
  2.  * Copyright (C) 2006 Ondrej Palkovsky
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /**
  30.  * Asynchronous library
  31.  *
  32.  * The aim of this library is facilitating writing programs utilizing
  33.  * the asynchronous nature of Helenos IPC, yet using a normal way
  34.  * of programming.
  35.  *
  36.  * You should be able to write very simple multithreaded programs,
  37.  * the async framework will automatically take care of most synchronization
  38.  * problems.
  39.  *
  40.  * Default semantics:
  41.  * - send() - send asynchronously. If the kernel refuses to send more
  42.  *            messages, [ try to get responses from kernel, if nothing
  43.  *            found, might try synchronous ]
  44.  *
  45.  * Example of use:
  46.  *
  47.  * 1) Multithreaded client application
  48.  *  create_thread(thread1);
  49.  *  create_thread(thread2);
  50.  *  ...
  51.  *  
  52.  *  thread1() {
  53.  *        conn = ipc_connect_me_to();
  54.  *        c1 = send(conn);
  55.  *        c2 = send(conn);
  56.  *        wait_for(c1);
  57.  *        wait_for(c2);
  58.  *  }
  59.  *
  60.  *
  61.  * 2) Multithreaded server application
  62.  * main() {
  63.  *      async_manager();
  64.  * }
  65.  *
  66.  *
  67.  * client_connection(icallid, *icall) {
  68.  *       if (want_refuse) {
  69.  *           ipc_answer_fast(icallid, ELIMIT, 0, 0);
  70.  *           return;
  71.  *       }
  72.  *       ipc_answer_fast(icallid, 0, 0, 0);
  73.  *
  74.  *       callid = async_get_call(&call);
  75.  *       handle(callid, call);
  76.  *       ipc_answer_fast(callid, 1,2,3);
  77.  *
  78.  *       callid = async_get_call(&call);
  79.  *       ....
  80.  * }
  81.  *
  82.  * TODO: Detaching/joining dead psthreads?
  83.  */
  84. #include <futex.h>
  85. #include <async.h>
  86. #include <psthread.h>
  87. #include <stdio.h>
  88. #include <libadt/hash_table.h>
  89. #include <libadt/list.h>
  90. #include <ipc/ipc.h>
  91. #include <assert.h>
  92. #include <errno.h>
  93. #include <time.h>
  94. #include <arch/barrier.h>
  95.  
  96. atomic_t async_futex = FUTEX_INITIALIZER;
  97. static hash_table_t conn_hash_table;
  98. static LIST_INITIALIZE(timeout_list);
  99.  
  100. typedef struct {
  101.     struct timeval expires;      /**< Expiration time for waiting thread */
  102.     int inlist;             /**< If true, this struct is in timeout list */
  103.     link_t link;
  104.  
  105.     pstid_t ptid;                /**< Thread waiting for this message */
  106.     int active;                  /**< If this thread is currently active */
  107.     int timedout;                /**< If true, we timed out */
  108. } awaiter_t;
  109.  
  110. typedef struct {
  111.     awaiter_t wdata;
  112.  
  113.     int done;                    /**< If reply was received */
  114.     ipc_call_t *dataptr;         /**< Pointer where the answer data
  115.                       *   is stored */
  116.     ipcarg_t retval;
  117. } amsg_t;
  118.  
  119. typedef struct {
  120.     link_t link;
  121.     ipc_callid_t callid;
  122.     ipc_call_t call;
  123. } msg_t;
  124.  
  125. typedef struct {
  126.     awaiter_t wdata;
  127.  
  128.     link_t link;             /**< Hash table link */
  129.     ipcarg_t in_phone_hash;  /**< Incoming phone hash. */
  130.     link_t msg_queue;        /**< Messages that should be delivered to this thread */
  131.     /* Structures for connection opening packet */
  132.     ipc_callid_t callid;
  133.     ipc_call_t call;
  134.     void (*cthread)(ipc_callid_t,ipc_call_t *);
  135. } connection_t;
  136.  
  137.  
  138. __thread connection_t *PS_connection;
  139.  
  140. static void default_client_connection(ipc_callid_t callid, ipc_call_t *call);
  141. static async_client_conn_t client_connection = default_client_connection;
  142.  
  143. /** Add microseconds to give timeval */
  144. static void tv_add(struct timeval *tv, suseconds_t usecs)
  145. {
  146.     tv->tv_sec += usecs / 1000000;
  147.     tv->tv_usec += usecs % 1000000;
  148.     if (tv->tv_usec > 1000000) {
  149.         tv->tv_sec++;
  150.         tv->tv_usec -= 1000000;
  151.     }
  152. }
  153.  
  154. /** Subtract 2 timevals, return microseconds difference */
  155. static suseconds_t tv_sub(struct timeval *tv1, struct timeval *tv2)
  156. {
  157.     suseconds_t result;
  158.  
  159.     result = tv1->tv_usec - tv2->tv_usec;
  160.     result += (tv1->tv_sec - tv2->tv_sec) * 1000000;
  161.  
  162.     return result;
  163. }
  164.  
  165. /** Compare timeval
  166.  *
  167.  * @return 1 if tv1 > tv2, otherwise 0
  168.  */
  169. static int tv_gt(struct timeval *tv1, struct timeval *tv2)
  170. {
  171.     if (tv1->tv_sec > tv2->tv_sec)
  172.         return 1;
  173.     if (tv1->tv_sec == tv2->tv_sec && tv1->tv_usec > tv2->tv_usec)
  174.         return 1;
  175.     return 0;
  176. }
  177. static int tv_gteq(struct timeval *tv1, struct timeval *tv2)
  178. {
  179.     if (tv1->tv_sec > tv2->tv_sec)
  180.         return 1;
  181.     if (tv1->tv_sec == tv2->tv_sec && tv1->tv_usec >= tv2->tv_usec)
  182.         return 1;
  183.     return 0;
  184. }
  185.  
  186. /* Hash table functions */
  187. #define CONN_HASH_TABLE_CHAINS  32
  188.  
  189. static hash_index_t conn_hash(unsigned long *key)
  190. {
  191.     assert(key);
  192.     return ((*key) >> 4) % CONN_HASH_TABLE_CHAINS;
  193. }
  194.  
  195. static int conn_compare(unsigned long key[], hash_count_t keys, link_t *item)
  196. {
  197.     connection_t *hs;
  198.  
  199.     hs = hash_table_get_instance(item, connection_t, link);
  200.    
  201.     return key[0] == hs->in_phone_hash;
  202. }
  203.  
  204. static void conn_remove(link_t *item)
  205. {
  206.     free(hash_table_get_instance(item, connection_t, link));
  207. }
  208.  
  209.  
  210. /** Operations for NS hash table. */
  211. static hash_table_operations_t conn_hash_table_ops = {
  212.     .hash = conn_hash,
  213.     .compare = conn_compare,
  214.     .remove_callback = conn_remove
  215. };
  216.  
  217. /** Insert sort timeout msg into timeouts list
  218.  *
  219.  */
  220. static void insert_timeout(awaiter_t *wd)
  221. {
  222.     link_t *tmp;
  223.     awaiter_t *cur;
  224.  
  225.     wd->timedout = 0;
  226.  
  227.     tmp = timeout_list.next;
  228.     while (tmp != &timeout_list) {
  229.         cur = list_get_instance(tmp, awaiter_t, link);
  230.         if (tv_gteq(&cur->expires, &wd->expires))
  231.             break;
  232.         tmp = tmp->next;
  233.     }
  234.     list_append(&wd->link, tmp);
  235. }
  236.  
  237. /*************************************************/
  238.  
  239. /** Try to route a call to an appropriate connection thread
  240.  *
  241.  */
  242. static int route_call(ipc_callid_t callid, ipc_call_t *call)
  243. {
  244.     connection_t *conn;
  245.     msg_t *msg;
  246.     link_t *hlp;
  247.     unsigned long key;
  248.  
  249.     futex_down(&async_futex);
  250.  
  251.     key = call->in_phone_hash;
  252.     hlp = hash_table_find(&conn_hash_table, &key);
  253.     if (!hlp) {
  254.         futex_up(&async_futex);
  255.         return 0;
  256.     }
  257.     conn = hash_table_get_instance(hlp, connection_t, link);
  258.  
  259.     msg = malloc(sizeof(*msg));
  260.     msg->callid = callid;
  261.     msg->call = *call;
  262.     list_append(&msg->link, &conn->msg_queue);
  263.    
  264.     /* If the call is waiting for event, run it */
  265.     if (!conn->wdata.active) {
  266.         /* If in timeout list, remove it */
  267.         if (conn->wdata.inlist) {
  268.             conn->wdata.inlist = 0;
  269.             list_remove(&conn->wdata.link);
  270.         }
  271.         conn->wdata.active = 1;
  272.         psthread_add_ready(conn->wdata.ptid);
  273.     }
  274.  
  275.     futex_up(&async_futex);
  276.  
  277.     return 1;
  278. }
  279.  
  280. /** Return new incoming message for current(thread-local) connection */
  281. ipc_callid_t async_get_call_timeout(ipc_call_t *call, suseconds_t usecs)
  282. {
  283.     msg_t *msg;
  284.     ipc_callid_t callid;
  285.     connection_t *conn;
  286.    
  287.     assert(PS_connection);
  288.     /* GCC 4.1.0 coughs on PS_connection-> dereference,
  289.      * GCC 4.1.1 happilly puts the rdhwr instruction in delay slot.
  290.      *           I would never expect to find so many errors in
  291.      *           compiler *($&$(*&$
  292.      */
  293.     conn = PS_connection;
  294.  
  295.     if (usecs < 0) /* TODO: let it get through the ipc_call once */
  296.         return 0;
  297.  
  298.     futex_down(&async_futex);
  299.  
  300.     if (usecs) {
  301.         gettimeofday(&conn->wdata.expires, NULL);
  302.         tv_add(&conn->wdata.expires, usecs);
  303.     } else {
  304.         conn->wdata.inlist = 0;
  305.     }
  306.     /* If nothing in queue, wait until something appears */
  307.     while (list_empty(&conn->msg_queue)) {
  308.         if (usecs) {
  309.             conn->wdata.inlist = 1;
  310.             insert_timeout(&conn->wdata);
  311.         }
  312.         conn->wdata.active = 0;
  313.         psthread_schedule_next_adv(PS_TO_MANAGER);
  314.         /* Futex is up after getting back from async_manager
  315.          * get it again */
  316.         futex_down(&async_futex);
  317.         if (usecs && conn->wdata.timedout && \
  318.             list_empty(&conn->msg_queue)) {
  319.             /* If we timed out-> exit */
  320.             futex_up(&async_futex);
  321.             return 0;
  322.         }
  323.     }
  324.    
  325.     msg = list_get_instance(conn->msg_queue.next, msg_t, link);
  326.     list_remove(&msg->link);
  327.     callid = msg->callid;
  328.     *call = msg->call;
  329.     free(msg);
  330.    
  331.     futex_up(&async_futex);
  332.     return callid;
  333. }
  334.  
  335. /** Thread function that gets created on new connection
  336.  *
  337.  * This function is defined as a weak symbol - to be redefined in
  338.  * user code.
  339.  */
  340. static void default_client_connection(ipc_callid_t callid, ipc_call_t *call)
  341. {
  342.     ipc_answer_fast(callid, ENOENT, 0, 0);
  343. }
  344.  
  345. /** Function that gets called on interrupt receival
  346.  *
  347.  * This function is defined as a weak symbol - to be redefined in
  348.  * user code.
  349.  */
  350. void interrupt_received(ipc_call_t *call)
  351. {
  352. }
  353.  
  354.  
  355. /** Wrapper for client connection thread
  356.  *
  357.  * When new connection arrives, thread with this function is created.
  358.  * It calls client_connection and does final cleanup.
  359.  *
  360.  * @parameter arg Connection structure pointer
  361.  */
  362. static int connection_thread(void  *arg)
  363. {
  364.     unsigned long key;
  365.     msg_t *msg;
  366.  
  367.     /* Setup thread local connection pointer */
  368.     PS_connection = (connection_t *)arg;
  369.     PS_connection->cthread(PS_connection->callid, &PS_connection->call);
  370.  
  371.     /* Remove myself from connection hash table */
  372.     futex_down(&async_futex);
  373.     key = PS_connection->in_phone_hash;
  374.     hash_table_remove(&conn_hash_table, &key, 1);
  375.     futex_up(&async_futex);
  376.     /* Answer all remaining messages with ehangup */
  377.     while (!list_empty(&PS_connection->msg_queue)) {
  378.         msg = list_get_instance(PS_connection->msg_queue.next, msg_t, link);
  379.         list_remove(&msg->link);
  380.         ipc_answer_fast(msg->callid, EHANGUP, 0, 0);
  381.         free(msg);
  382.     }
  383. }
  384.  
  385. /** Create new thread for a new connection
  386.  *
  387.  * Creates new thread for connection, fills in connection
  388.  * structures and inserts it into the hash table, so that
  389.  * later we can easily do routing of messages to particular
  390.  * threads.
  391.  *
  392.  * @param in_phone_hash Identification of the incoming connection
  393.  * @param callid Callid of the IPC_M_CONNECT_ME_TO packet
  394.  * @param call Call data of the opening packet
  395.  * @param cthread Thread function that should be called upon
  396.  *                opening the connection
  397.  * @return New thread id
  398.  */
  399. pstid_t async_new_connection(ipcarg_t in_phone_hash,ipc_callid_t callid,
  400.                  ipc_call_t *call,
  401.                  void (*cthread)(ipc_callid_t,ipc_call_t *))
  402. {
  403.     pstid_t ptid;
  404.     connection_t *conn;
  405.     unsigned long key;
  406.  
  407.     conn = malloc(sizeof(*conn));
  408.     if (!conn) {
  409.         ipc_answer_fast(callid, ENOMEM, 0, 0);
  410.         return NULL;
  411.     }
  412.     conn->in_phone_hash = in_phone_hash;
  413.     list_initialize(&conn->msg_queue);
  414.     conn->callid = callid;
  415.     if (call)
  416.         conn->call = *call;
  417.     conn->wdata.active = 1; /* We will activate it asap */
  418.     conn->cthread = cthread;
  419.  
  420.     conn->wdata.ptid = psthread_create(connection_thread, conn);
  421.     if (!conn->wdata.ptid) {
  422.         free(conn);
  423.         ipc_answer_fast(callid, ENOMEM, 0, 0);
  424.         return NULL;
  425.     }
  426.     /* Add connection to hash table */
  427.     key = conn->in_phone_hash;
  428.     futex_down(&async_futex);
  429.     hash_table_insert(&conn_hash_table, &key, &conn->link);
  430.     futex_up(&async_futex);
  431.  
  432.     psthread_add_ready(conn->wdata.ptid);
  433.  
  434.     return conn->wdata.ptid;
  435. }
  436.  
  437. /** Handle call that was received */
  438. static void handle_call(ipc_callid_t callid, ipc_call_t *call)
  439. {
  440.     /* Unrouted call - do some default behaviour */
  441.     switch (IPC_GET_METHOD(*call)) {
  442.     case IPC_M_INTERRUPT:
  443.         interrupt_received(call);
  444.         return;
  445.     case IPC_M_CONNECT_ME_TO:
  446.         /* Open new connection with thread etc. */
  447.         async_new_connection(IPC_GET_ARG3(*call), callid, call, client_connection);
  448.         return;
  449.     }
  450.  
  451.     /* Try to route call through connection tables */
  452.     if (route_call(callid, call))
  453.         return;
  454.  
  455.     /* Unknown call from unknown phone - hang it up */
  456.     ipc_answer_fast(callid, EHANGUP, 0, 0);
  457. }
  458.  
  459. /** Fire all timeouts that expired
  460.  *
  461.  */
  462. static void handle_expired_timeouts(void)
  463. {
  464.     struct timeval tv;
  465.     awaiter_t *waiter;
  466.     link_t *cur;
  467.  
  468.     gettimeofday(&tv,NULL);
  469.     futex_down(&async_futex);
  470.  
  471.     cur = timeout_list.next;
  472.     while (cur != &timeout_list) {
  473.         waiter = list_get_instance(cur,awaiter_t,link);
  474.         if (tv_gt(&waiter->expires, &tv))
  475.             break;
  476.         cur = cur->next;
  477.         list_remove(&waiter->link);
  478.         waiter->inlist = 0;
  479.         waiter->timedout = 1;
  480.         /* Redundant condition? The thread should not
  481.          * be active when it gets here.
  482.          */
  483.         if (!waiter->active) {
  484.             waiter->active = 1;
  485.             psthread_add_ready(waiter->ptid);
  486.         }
  487.     }
  488.  
  489.     futex_up(&async_futex);
  490. }
  491.  
  492. /** Endless loop dispatching incoming calls and answers */
  493. int async_manager(void)
  494. {
  495.     ipc_call_t call;
  496.     ipc_callid_t callid;
  497.     int timeout;
  498.     awaiter_t *waiter;
  499.     struct timeval tv;
  500.  
  501.     while (1) {
  502.         if (psthread_schedule_next_adv(PS_FROM_MANAGER)) {
  503.             futex_up(&async_futex); /* async_futex is always held
  504.                         * when entering manager thread
  505.                         */
  506.             continue;
  507.         }
  508.         futex_down(&async_futex);
  509.         if (!list_empty(&timeout_list)) {
  510.             waiter = list_get_instance(timeout_list.next,awaiter_t,link);
  511.             gettimeofday(&tv,NULL);
  512.             if (tv_gteq(&tv, &waiter->expires)) {
  513.                 futex_up(&async_futex);
  514.                 handle_expired_timeouts();
  515.                 continue;
  516.             } else
  517.                 timeout = tv_sub(&waiter->expires, &tv);
  518.         } else
  519.             timeout = SYNCH_NO_TIMEOUT;
  520.         futex_up(&async_futex);
  521.  
  522.         callid = ipc_wait_cycle(&call, timeout, SYNCH_FLAGS_NONE);
  523.  
  524.         if (!callid) {
  525.             handle_expired_timeouts();
  526.             continue;
  527.         }
  528.  
  529.         if (callid & IPC_CALLID_ANSWERED)
  530.             continue;
  531.  
  532.         handle_call(callid, &call);
  533.     }
  534. }
  535.  
  536. /** Function to start async_manager as a standalone thread
  537.  *
  538.  * When more kernel threads are used, one async manager should
  539.  * exist per thread. The particular implementation may change,
  540.  * currently one async_manager is started automatically per kernel
  541.  * thread except main thread.
  542.  */
  543. static int async_manager_thread(void *arg)
  544. {
  545.     futex_up(&async_futex); /* async_futex is always locked when entering
  546.                 * manager */
  547.     async_manager();
  548. }
  549.  
  550. /** Add one manager to manager list */
  551. void async_create_manager(void)
  552. {
  553.     pstid_t ptid;
  554.  
  555.     ptid = psthread_create(async_manager_thread, NULL);
  556.     psthread_add_manager(ptid);
  557. }
  558.  
  559. /** Remove one manager from manager list */
  560. void async_destroy_manager(void)
  561. {
  562.     psthread_remove_manager();
  563. }
  564.  
  565. /** Initialize internal structures needed for async manager */
  566. int _async_init(void)
  567. {
  568.     if (!hash_table_create(&conn_hash_table, CONN_HASH_TABLE_CHAINS, 1, &conn_hash_table_ops)) {
  569.         printf("%s: cannot create hash table\n", "async");
  570.         return ENOMEM;
  571.     }
  572.    
  573. }
  574.  
  575. /** IPC handler for messages in async framework
  576.  *
  577.  * Notify thread that is waiting for this message, that it arrived
  578.  */
  579. static void reply_received(void *private, int retval,
  580.                ipc_call_t *data)
  581. {
  582.     amsg_t *msg = (amsg_t *) private;
  583.  
  584.     msg->retval = retval;
  585.  
  586.     futex_down(&async_futex);
  587.     /* Copy data after futex_down, just in case the
  588.      * call was detached
  589.      */
  590.     if (msg->dataptr)
  591.         *msg->dataptr = *data;
  592.  
  593.     write_barrier();
  594.     /* Remove message from timeout list */
  595.     if (msg->wdata.inlist)
  596.         list_remove(&msg->wdata.link);
  597.     msg->done = 1;
  598.     if (! msg->wdata.active) {
  599.         msg->wdata.active = 1;
  600.         psthread_add_ready(msg->wdata.ptid);
  601.     }
  602.     futex_up(&async_futex);
  603. }
  604.  
  605. /** Send message and return id of the sent message
  606.  *
  607.  * The return value can be used as input for async_wait() to wait
  608.  * for completion.
  609.  */
  610. aid_t async_send_2(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,
  611.            ipc_call_t *dataptr)
  612. {
  613.     amsg_t *msg;
  614.  
  615.     msg = malloc(sizeof(*msg));
  616.     msg->done = 0;
  617.     msg->dataptr = dataptr;
  618.  
  619.     msg->wdata.active = 1; /* We may sleep in next method, but it
  620.                 * will use it's own mechanism */
  621.     ipc_call_async_2(phoneid,method,arg1,arg2,msg,reply_received,1);
  622.  
  623.     return (aid_t) msg;
  624. }
  625.  
  626. /** Wait for a message sent by async framework
  627.  *
  628.  * @param amsgid Message ID to wait for
  629.  * @param retval Pointer to variable where will be stored retval
  630.  *               of the answered message. If NULL, it is ignored.
  631.  *
  632.  */
  633. void async_wait_for(aid_t amsgid, ipcarg_t *retval)
  634. {
  635.     amsg_t *msg = (amsg_t *) amsgid;
  636.     connection_t *conn;
  637.  
  638.     futex_down(&async_futex);
  639.     if (msg->done) {
  640.         futex_up(&async_futex);
  641.         goto done;
  642.     }
  643.  
  644.     msg->wdata.ptid = psthread_get_id();
  645.     msg->wdata.active = 0;
  646.     msg->wdata.inlist = 0;
  647.     /* Leave locked async_futex when entering this function */
  648.     psthread_schedule_next_adv(PS_TO_MANAGER);
  649.     /* futex is up automatically after psthread_schedule_next...*/
  650. done:
  651.     if (retval)
  652.         *retval = msg->retval;
  653.     free(msg);
  654. }
  655.  
  656. /** Wait for a message sent by async framework with timeout
  657.  *
  658.  * @param amsgid Message ID to wait for
  659.  * @param retval Pointer to variable where will be stored retval
  660.  *               of the answered message. If NULL, it is ignored.
  661.  * @param timeout Timeout in usecs
  662.  * @return 0 on success, ETIMEOUT if timeout expired
  663.  *
  664.  */
  665. int async_wait_timeout(aid_t amsgid, ipcarg_t *retval, suseconds_t timeout)
  666. {
  667.     amsg_t *msg = (amsg_t *) amsgid;
  668.     connection_t *conn;
  669.  
  670.     /* TODO: Let it go through the event read at least once */
  671.     if (timeout < 0)
  672.         return ETIMEOUT;
  673.  
  674.     futex_down(&async_futex);
  675.     if (msg->done) {
  676.         futex_up(&async_futex);
  677.         goto done;
  678.     }
  679.  
  680.     gettimeofday(&msg->wdata.expires, NULL);
  681.     tv_add(&msg->wdata.expires, timeout);
  682.  
  683.     msg->wdata.ptid = psthread_get_id();
  684.     msg->wdata.active = 0;
  685.     msg->wdata.inlist = 1;
  686.  
  687.     insert_timeout(&msg->wdata);
  688.  
  689.     /* Leave locked async_futex when entering this function */
  690.     psthread_schedule_next_adv(PS_TO_MANAGER);
  691.     /* futex is up automatically after psthread_schedule_next...*/
  692.  
  693.     if (!msg->done)
  694.         return ETIMEOUT;
  695.  
  696. done:
  697.     if (retval)
  698.         *retval = msg->retval;
  699.     free(msg);
  700.  
  701.     return 0;
  702. }
  703.  
  704. /** Wait specified time, but in the meantime handle incoming events
  705.  *
  706.  * @param timeout Time in microseconds to wait
  707.  */
  708. void async_usleep(suseconds_t timeout)
  709. {
  710.     amsg_t *msg;
  711.    
  712.     msg = malloc(sizeof(*msg));
  713.     if (!msg)
  714.         return;
  715.  
  716.     msg->wdata.ptid = psthread_get_id();
  717.     msg->wdata.inlist = 1;
  718.     msg->wdata.active = 0;
  719.  
  720.     gettimeofday(&msg->wdata.expires, NULL);
  721.     tv_add(&msg->wdata.expires, timeout);
  722.  
  723.     futex_down(&async_futex);
  724.     insert_timeout(&msg->wdata);
  725.     /* Leave locked async_futex when entering this function */
  726.     psthread_schedule_next_adv(PS_TO_MANAGER);
  727.     /* futex is up automatically after psthread_schedule_next...*/
  728.     free(msg);
  729. }
  730.  
  731. /** Set function that is called, IPC_M_CONNECT_ME_TO is received
  732.  *
  733.  * @param conn Function that will form new psthread.
  734.  */
  735. void async_set_client_connection(async_client_conn_t conn)
  736. {
  737.     client_connection = conn;
  738. }
  739.