Subversion Repositories HelenOS-historic

Rev

Rev 1453 | Rev 1470 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  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.     pstid_t ptid;                /**< Thread waiting for this message */
  102.     int active;                  /**< If this thread is currently active */
  103.     int done;                    /**< If reply was received */
  104.     ipc_call_t *dataptr;         /**< Pointer where the answer data
  105.                       *   should be stored */
  106.     struct timeval expires;      /**< Expiration time for waiting thread */
  107.     int has_timeout;             /**< If true, this struct is in timeout list */
  108.     link_t link;
  109.  
  110.     ipcarg_t retval;
  111. } amsg_t;
  112.  
  113. typedef struct {
  114.     link_t link;
  115.     ipc_callid_t callid;
  116.     ipc_call_t call;
  117. } msg_t;
  118.  
  119. typedef struct {
  120.     link_t link;
  121.     ipcarg_t in_phone_hash;     /**< Incoming phone hash. */
  122.     link_t msg_queue;              /**< Messages that should be delivered to this thread */
  123.     pstid_t ptid;                /**< Thread associated with this connection */
  124.     int active;                     /**< If this thread is currently active */
  125.     /* Structures for connection opening packet */
  126.     ipc_callid_t callid;
  127.     ipc_call_t call;
  128.     void (*cthread)(ipc_callid_t,ipc_call_t *);
  129. } connection_t;
  130.  
  131. __thread connection_t *PS_connection;
  132.  
  133. /** Add microseconds to give timeval */
  134. static void tv_add(struct timeval *tv, suseconds_t usecs)
  135. {
  136.     tv->tv_sec += usecs / 1000000;
  137.     tv->tv_usec += usecs % 1000000;
  138.     if (tv->tv_usec > 1000000) {
  139.         tv->tv_sec++;
  140.         tv->tv_usec -= 1000000;
  141.     }
  142. }
  143.  
  144. /** Subtract 2 timevals, return microseconds difference */
  145. static suseconds_t tv_sub(struct timeval *tv1, struct timeval *tv2)
  146. {
  147.     suseconds_t result;
  148.  
  149.     result = tv1->tv_usec - tv2->tv_usec;
  150.     result += (tv1->tv_sec - tv2->tv_sec) * 1000000;
  151.  
  152.     return result;
  153. }
  154.  
  155. /** Compare timeval
  156.  *
  157.  * @return 1 if tv1 > tv2, otherwise 0
  158.  */
  159. static int tv_gt(struct timeval *tv1, struct timeval *tv2)
  160. {
  161.     if (tv1->tv_sec > tv2->tv_sec)
  162.         return 1;
  163.     if (tv1->tv_sec == tv2->tv_sec && tv1->tv_usec > tv2->tv_usec)
  164.         return 1;
  165.     return 0;
  166. }
  167.  
  168. /* Hash table functions */
  169. #define CONN_HASH_TABLE_CHAINS  32
  170.  
  171. static hash_index_t conn_hash(unsigned long *key)
  172. {
  173.     assert(key);
  174.     return ((*key) >> 4) % CONN_HASH_TABLE_CHAINS;
  175. }
  176.  
  177. static int conn_compare(unsigned long key[], hash_count_t keys, link_t *item)
  178. {
  179.     connection_t *hs;
  180.  
  181.     hs = hash_table_get_instance(item, connection_t, link);
  182.    
  183.     return key[0] == hs->in_phone_hash;
  184. }
  185.  
  186. static void conn_remove(link_t *item)
  187. {
  188.     free(hash_table_get_instance(item, connection_t, link));
  189. }
  190.  
  191.  
  192. /** Operations for NS hash table. */
  193. static hash_table_operations_t conn_hash_table_ops = {
  194.     .hash = conn_hash,
  195.     .compare = conn_compare,
  196.     .remove_callback = conn_remove
  197. };
  198.  
  199. /*************************************************/
  200.  
  201. /** Try to route a call to an appropriate connection thread
  202.  *
  203.  */
  204. static int route_call(ipc_callid_t callid, ipc_call_t *call)
  205. {
  206.     connection_t *conn;
  207.     msg_t *msg;
  208.     link_t *hlp;
  209.     unsigned long key;
  210.  
  211.     futex_down(&async_futex);
  212.  
  213.     key = call->in_phone_hash;
  214.     hlp = hash_table_find(&conn_hash_table, &key);
  215.     if (!hlp) {
  216.         futex_up(&async_futex);
  217.         return 0;
  218.     }
  219.     conn = hash_table_get_instance(hlp, connection_t, link);
  220.  
  221.     msg = malloc(sizeof(*msg));
  222.     msg->callid = callid;
  223.     msg->call = *call;
  224.     list_append(&msg->link, &conn->msg_queue);
  225.    
  226.     if (!conn->active) {
  227.         conn->active = 1;
  228.         psthread_add_ready(conn->ptid);
  229.     }
  230.  
  231.     futex_up(&async_futex);
  232.  
  233.     return 1;
  234. }
  235.  
  236. /** Return new incoming message for current(thread-local) connection */
  237. ipc_callid_t async_get_call(ipc_call_t *call)
  238. {
  239.     msg_t *msg;
  240.     ipc_callid_t callid;
  241.     connection_t *conn;
  242.    
  243.     futex_down(&async_futex);
  244.  
  245.     conn = PS_connection;
  246.     /* If nothing in queue, wait until something appears */
  247.     if (list_empty(&conn->msg_queue)) {
  248.         conn->active = 0;
  249.         psthread_schedule_next_adv(PS_TO_MANAGER);
  250.     }
  251.    
  252.     msg = list_get_instance(conn->msg_queue.next, msg_t, link);
  253.     list_remove(&msg->link);
  254.     callid = msg->callid;
  255.     *call = msg->call;
  256.     free(msg);
  257.    
  258.     futex_up(&async_futex);
  259.     return callid;
  260. }
  261.  
  262. /** Thread function that gets created on new connection
  263.  *
  264.  * This function is defined as a weak symbol - to be redefined in
  265.  * user code.
  266.  */
  267. void client_connection(ipc_callid_t callid, ipc_call_t *call)
  268. {
  269.     ipc_answer_fast(callid, ENOENT, 0, 0);
  270. }
  271.  
  272. /** Function that gets called on interrupt receival
  273.  *
  274.  * This function is defined as a weak symbol - to be redefined in
  275.  * user code.
  276.  */
  277. void interrupt_received(ipc_call_t *call)
  278. {
  279. }
  280.  
  281.  
  282. /** Wrapper for client connection thread
  283.  *
  284.  * When new connection arrives, thread with this function is created.
  285.  * It calls client_connection and does final cleanup.
  286.  *
  287.  * @parameter arg Connection structure pointer
  288.  */
  289. static int connection_thread(void  *arg)
  290. {
  291.     unsigned long key;
  292.     msg_t *msg;
  293.     connection_t *conn;
  294.  
  295.     /* Setup thread local connection pointer */
  296.     PS_connection = (connection_t *)arg;
  297.     conn = PS_connection;
  298.     conn->cthread(conn->callid, &conn->call);
  299.  
  300.     /* Remove myself from connection hash table */
  301.     futex_down(&async_futex);
  302.     key = conn->in_phone_hash;
  303.     hash_table_remove(&conn_hash_table, &key, 1);
  304.     futex_up(&async_futex);
  305.     /* Answer all remaining messages with ehangup */
  306.     while (!list_empty(&conn->msg_queue)) {
  307.         msg = list_get_instance(conn->msg_queue.next, msg_t, link);
  308.         list_remove(&msg->link);
  309.         ipc_answer_fast(msg->callid, EHANGUP, 0, 0);
  310.         free(msg);
  311.     }
  312. }
  313.  
  314. /** Create new thread for a new connection
  315.  *
  316.  * Creates new thread for connection, fills in connection
  317.  * structures and inserts it into the hash table, so that
  318.  * later we can easily do routing of messages to particular
  319.  * threads.
  320.  *
  321.  * @param in_phone_hash Identification of the incoming connection
  322.  * @param callid Callid of the IPC_M_CONNECT_ME_TO packet
  323.  * @param call Call data of the opening packet
  324.  * @param cthread Thread function that should be called upon
  325.  *                opening the connection
  326.  * @return New thread id
  327.  */
  328. pstid_t async_new_connection(ipcarg_t in_phone_hash,ipc_callid_t callid,
  329.                  ipc_call_t *call,
  330.                  void (*cthread)(ipc_callid_t,ipc_call_t *))
  331. {
  332.     pstid_t ptid;
  333.     connection_t *conn;
  334.     unsigned long key;
  335.  
  336.     conn = malloc(sizeof(*conn));
  337.     if (!conn) {
  338.         ipc_answer_fast(callid, ENOMEM, 0, 0);
  339.         return NULL;
  340.     }
  341.     conn->in_phone_hash = in_phone_hash;
  342.     list_initialize(&conn->msg_queue);
  343.     conn->ptid = psthread_create(connection_thread, conn);
  344.     conn->callid = callid;
  345.     if (call)
  346.         conn->call = *call;
  347.     conn->active = 1; /* We will activate it asap */
  348.     conn->cthread = cthread;
  349.     list_initialize(&conn->link);
  350.     if (!conn->ptid) {
  351.         free(conn);
  352.         ipc_answer_fast(callid, ENOMEM, 0, 0);
  353.         return NULL;
  354.     }
  355.     key = conn->in_phone_hash;
  356.     futex_down(&async_futex);
  357.     /* Add connection to hash table */
  358.     hash_table_insert(&conn_hash_table, &key, &conn->link);
  359.     futex_up(&async_futex);
  360.  
  361.     psthread_add_ready(conn->ptid);
  362.  
  363.     return conn->ptid;
  364. }
  365.  
  366. /** Handle call that was received */
  367. static void handle_call(ipc_callid_t callid, ipc_call_t *call)
  368. {
  369.     /* Unrouted call - do some default behaviour */
  370.     switch (IPC_GET_METHOD(*call)) {
  371.     case IPC_M_INTERRUPT:
  372.         interrupt_received(call);
  373.         return;
  374.     case IPC_M_CONNECT_ME_TO:
  375.         /* Open new connection with thread etc. */
  376.         async_new_connection(IPC_GET_ARG3(*call), callid, call, client_connection);
  377.         return;
  378.     }
  379.  
  380.     /* Try to route call through connection tables */
  381.     if (route_call(callid, call))
  382.         return;
  383.  
  384.     /* Unknown call from unknown phone - hang it up */
  385.     ipc_answer_fast(callid, EHANGUP, 0, 0);
  386. }
  387.  
  388. /** Fire all timeouts that expired */
  389. static void handle_expired_timeouts(void)
  390. {
  391.     struct timeval tv;
  392.     amsg_t *amsg;
  393.     link_t *cur;
  394.  
  395.     gettimeofday(&tv,NULL);
  396.     futex_down(&async_futex);
  397.  
  398.     cur = timeout_list.next;
  399.     while (cur != &timeout_list) {
  400.         amsg = list_get_instance(cur,amsg_t,link);
  401.         if (tv_gt(&amsg->expires, &tv))
  402.             break;
  403.         cur = cur->next;
  404.         list_remove(&amsg->link);
  405.         amsg->has_timeout = 0;
  406.         /* Redundant condition? The thread should not
  407.          * be active when it gets here.
  408.          */
  409.         if (!amsg->active) {
  410.             amsg->active = 1;
  411.             psthread_add_ready(amsg->ptid);        
  412.         }
  413.     }
  414.  
  415.     futex_up(&async_futex);
  416. }
  417.  
  418. /** Endless loop dispatching incoming calls and answers */
  419. int async_manager(void)
  420. {
  421.     ipc_call_t call;
  422.     ipc_callid_t callid;
  423.     int timeout;
  424.     amsg_t *amsg;
  425.     struct timeval tv;
  426.  
  427.     while (1) {
  428.         if (psthread_schedule_next_adv(PS_FROM_MANAGER)) {
  429.             futex_up(&async_futex); /* async_futex is always held
  430.                         * when entering manager thread
  431.                         */
  432.             continue;
  433.         }
  434.         futex_down(&async_futex);
  435.         if (!list_empty(&timeout_list)) {
  436.             amsg = list_get_instance(timeout_list.next,amsg_t,link);
  437.             gettimeofday(&tv,NULL);
  438.             if (tv_gt(&tv, &amsg->expires)) {
  439.                 handle_expired_timeouts();
  440.                 continue;
  441.             } else
  442.                 timeout = tv_sub(&amsg->expires, &tv);
  443.         } else
  444.             timeout = SYNCH_NO_TIMEOUT;
  445.         futex_up(&async_futex);
  446.  
  447.         callid = ipc_wait_cycle(&call, timeout, SYNCH_BLOCKING);
  448.  
  449.         if (!callid) {
  450.             handle_expired_timeouts();
  451.             continue;
  452.         }
  453.  
  454.         if (callid & IPC_CALLID_ANSWERED)
  455.             continue;
  456.  
  457.         handle_call(callid, &call);
  458.     }
  459. }
  460.  
  461. /** Function to start async_manager as a standalone thread
  462.  *
  463.  * When more kernel threads are used, one async manager should
  464.  * exist per thread. The particular implementation may change,
  465.  * currently one async_manager is started automatically per kernel
  466.  * thread except main thread.
  467.  */
  468. static int async_manager_thread(void *arg)
  469. {
  470.     futex_up(&async_futex); /* async_futex is always locked when entering
  471.                 * manager */
  472.     async_manager();
  473. }
  474.  
  475. /** Add one manager to manager list */
  476. void async_create_manager(void)
  477. {
  478.     pstid_t ptid;
  479.  
  480.     ptid = psthread_create(async_manager_thread, NULL);
  481.     psthread_add_manager(ptid);
  482. }
  483.  
  484. /** Remove one manager from manager list */
  485. void async_destroy_manager(void)
  486. {
  487.     psthread_remove_manager();
  488. }
  489.  
  490. /** Initialize internal structures needed for async manager */
  491. int _async_init(void)
  492. {
  493.     if (!hash_table_create(&conn_hash_table, CONN_HASH_TABLE_CHAINS, 1, &conn_hash_table_ops)) {
  494.         printf("%s: cannot create hash table\n", "async");
  495.         return ENOMEM;
  496.     }
  497.    
  498. }
  499.  
  500. /** IPC handler for messages in async framework
  501.  *
  502.  * Notify thread that is waiting for this message, that it arrived
  503.  */
  504. static void reply_received(void *private, int retval,
  505.                ipc_call_t *data)
  506. {
  507.     amsg_t *msg = (amsg_t *) private;
  508.  
  509.     msg->retval = retval;
  510.  
  511.     futex_down(&async_futex);
  512.     /* Copy data after futex_down, just in case the
  513.      * call was detached
  514.      */
  515.     if (msg->dataptr)
  516.         *msg->dataptr = *data;
  517.  
  518.     write_barrier();
  519.     /* Remove message from timeout list */
  520.     if (msg->has_timeout)
  521.         list_remove(&msg->link);
  522.     msg->done = 1;
  523.     if (! msg->active) {
  524.         msg->active = 1;
  525.         psthread_add_ready(msg->ptid);
  526.     }
  527.     futex_up(&async_futex);
  528. }
  529.  
  530. /** Send message and return id of the sent message
  531.  *
  532.  * The return value can be used as input for async_wait() to wait
  533.  * for completion.
  534.  */
  535. aid_t async_send_2(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,
  536.            ipc_call_t *dataptr)
  537. {
  538.     amsg_t *msg;
  539.  
  540.     msg = malloc(sizeof(*msg));
  541.     msg->active = 1;
  542.     msg->done = 0;
  543.     msg->dataptr = dataptr;
  544.     ipc_call_async_2(phoneid,method,arg1,arg2,msg,reply_received);
  545.  
  546.     return (aid_t) msg;
  547. }
  548.  
  549. /** Wait for a message sent by async framework
  550.  *
  551.  * @param amsgid Message ID to wait for
  552.  * @param retval Pointer to variable where will be stored retval
  553.  *               of the answered message. If NULL, it is ignored.
  554.  *
  555.  */
  556. void async_wait_for(aid_t amsgid, ipcarg_t *retval)
  557. {
  558.     amsg_t *msg = (amsg_t *) amsgid;
  559.     connection_t *conn;
  560.  
  561.     futex_down(&async_futex);
  562.     if (msg->done) {
  563.         futex_up(&async_futex);
  564.         goto done;
  565.     }
  566.  
  567.     msg->ptid = psthread_get_id();
  568.     msg->active = 0;
  569.     msg->has_timeout = 0;
  570.     /* Leave locked async_futex when entering this function */
  571.     psthread_schedule_next_adv(PS_TO_MANAGER);
  572.     /* futex is up automatically after psthread_schedule_next...*/
  573. done:
  574.     if (retval)
  575.         *retval = msg->retval;
  576.     free(msg);
  577. }
  578.  
  579. /** Insert sort timeout msg into timeouts list
  580.  *
  581.  * Assume async_futex is held
  582.  */
  583. static void insert_timeout(amsg_t *msg)
  584. {
  585.     link_t *tmp;
  586.     amsg_t *cur;
  587.  
  588.     tmp = timeout_list.next;
  589.     while (tmp != &timeout_list) {
  590.         cur = list_get_instance(tmp, amsg_t, link);
  591.         if (tv_gt(&cur->expires, &msg->expires))
  592.             break;
  593.         tmp = tmp->next;
  594.     }
  595.     list_append(&msg->link, tmp);
  596. }
  597.  
  598. /** Wait for a message sent by async framework with timeout
  599.  *
  600.  * @param amsgid Message ID to wait for
  601.  * @param retval Pointer to variable where will be stored retval
  602.  *               of the answered message. If NULL, it is ignored.
  603.  * @param timeout Timeout in usecs
  604.  * @return 0 on success, ETIMEOUT if timeout expired
  605.  *
  606.  */
  607. int async_wait_timeout(aid_t amsgid, ipcarg_t *retval, suseconds_t timeout)
  608. {
  609.     amsg_t *msg = (amsg_t *) amsgid;
  610.     connection_t *conn;
  611.  
  612.     futex_down(&async_futex);
  613.     if (msg->done) {
  614.         futex_up(&async_futex);
  615.         goto done;
  616.     }
  617.  
  618.     msg->ptid = psthread_get_id();
  619.     msg->active = 0;
  620.     msg->has_timeout = 1;
  621.  
  622.     gettimeofday(&msg->expires, NULL);
  623.     tv_add(&msg->expires, timeout);
  624.     insert_timeout(msg);
  625.  
  626.     /* Leave locked async_futex when entering this function */
  627.     psthread_schedule_next_adv(PS_TO_MANAGER);
  628.     /* futex is up automatically after psthread_schedule_next...*/
  629.  
  630.     if (!msg->done)
  631.         return ETIMEOUT;
  632.  
  633. done:
  634.     if (retval)
  635.         *retval = msg->retval;
  636.     free(msg);
  637.  
  638.     return 0;
  639. }
  640.  
  641. /** Wait specified time, but in the meantime handle incoming events
  642.  *
  643.  * @param timeout Time in microseconds to wait
  644.  */
  645. void async_usleep(suseconds_t timeout)
  646. {
  647.     amsg_t *msg;
  648.    
  649.     msg = malloc(sizeof(*msg));
  650.     if (!msg)
  651.         return;
  652.  
  653.     msg->ptid = psthread_get_id();
  654.     msg->active = 0;
  655.     msg->has_timeout = 1;
  656.  
  657.     gettimeofday(&msg->expires, NULL);
  658.     tv_add(&msg->expires, timeout);
  659.  
  660.     futex_down(&async_futex);
  661.     insert_timeout(msg);
  662.     /* Leave locked async_futex when entering this function */
  663.     psthread_schedule_next_adv(PS_TO_MANAGER);
  664.     /* futex is up automatically after psthread_schedule_next...*/
  665.     free(msg);
  666. }
  667.