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1351 palkovsky 1
/*
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 * Copyright (C) 2006 Ondrej Palkovsky
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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1392 palkovsky 29
/**
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 * Asynchronous library
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 *
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 * The aim of this library is facilitating writing programs utilizing
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 * the asynchronous nature of Helenos IPC, yet using a normal way
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 * of programming.
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 *
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 * You should be able to write very simple multithreaded programs,
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 * the async framework will automatically take care of most synchronization
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 * problems.
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 *
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 * Default semantics:
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 * - send() - send asynchronously. If the kernel refuses to send more
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 *            messages, [ try to get responses from kernel, if nothing
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 *            found, might try synchronous ]
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 *
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 * Example of use:
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 *
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 * 1) Multithreaded client application
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 *  create_thread(thread1);
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 *  create_thread(thread2);
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 *  ...
51
 *  
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 *  thread1() {
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 *        conn = ipc_connect_me_to();
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 *        c1 = send(conn);
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 *        c2 = send(conn);
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 *        wait_for(c1);
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 *        wait_for(c2);
58
 *  }
59
 *
60
 *
61
 * 2) Multithreaded server application
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 * main() {
63
 *      wait_for_connection(new_connection);
64
 * }
65
 *
66
 *
67
 * new_connection(int connection) {
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 *       accept(connection);
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 *       msg = get_msg();
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 *       handle(msg);
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 *       answer(msg);
72
 *
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 *       msg = get_msg();
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 *       ....
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 * }
1404 palkovsky 76
 *
1405 decky 77
 * TODO: Detaching/joining dead psthreads?
1392 palkovsky 78
 */
79
#include <futex.h>
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#include <async.h>
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#include <psthread.h>
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#include <stdio.h>
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#include <libadt/hash_table.h>
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#include <libadt/list.h>
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#include <ipc/ipc.h>
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#include <assert.h>
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#include <errno.h>
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89
static atomic_t conn_futex = FUTEX_INITIALIZER;
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static hash_table_t conn_hash_table;
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92
typedef struct {
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    link_t link;
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    ipc_callid_t callid;
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    ipc_call_t call;
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} msg_t;
97
 
98
typedef struct {
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    link_t link;
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    ipcarg_t in_phone_hash;     /**< Incoming phone hash. */
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    link_t msg_queue;              /**< Messages that should be delivered to this thread */
102
    pstid_t ptid;                /**< Thread associated with this connection */
103
    int active;                     /**< If this thread is currently active */
104
    /* Structures for connection opening packet */
105
    ipc_callid_t callid;
106
    ipc_call_t call;
107
} connection_t;
108
 
109
__thread connection_t *PS_connection;
110
 
111
/* Hash table functions */
112
 
1404 palkovsky 113
#define CONN_HASH_TABLE_CHAINS  32
1392 palkovsky 114
 
115
static hash_index_t conn_hash(unsigned long *key)
1351 palkovsky 116
{
1392 palkovsky 117
    assert(key);
1404 palkovsky 118
    return ((*key) >> 4) % CONN_HASH_TABLE_CHAINS;
1351 palkovsky 119
}
120
 
1392 palkovsky 121
static int conn_compare(unsigned long key[], hash_count_t keys, link_t *item)
1351 palkovsky 122
{
1392 palkovsky 123
    connection_t *hs;
124
 
125
    hs = hash_table_get_instance(item, connection_t, link);
126
 
127
    return key[0] == hs->in_phone_hash;
1351 palkovsky 128
}
129
 
1392 palkovsky 130
static void conn_remove(link_t *item)
1351 palkovsky 131
{
1392 palkovsky 132
    free(hash_table_get_instance(item, connection_t, link));
1351 palkovsky 133
}
134
 
1392 palkovsky 135
 
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/** Operations for NS hash table. */
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static hash_table_operations_t conn_hash_table_ops = {
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    .hash = conn_hash,
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    .compare = conn_compare,
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    .remove_callback = conn_remove
141
};
142
 
143
/** Try to route a call to an appropriate connection thread
144
 *
145
 */
146
static int route_call(ipc_callid_t callid, ipc_call_t *call)
1351 palkovsky 147
{
1392 palkovsky 148
    connection_t *conn;
149
    msg_t *msg;
150
    link_t *hlp;
151
    unsigned long key;
152
 
153
    futex_down(&conn_futex);
154
 
155
    key = call->in_phone_hash;
156
    hlp = hash_table_find(&conn_hash_table, &key);
157
    if (!hlp) {
158
        futex_up(&conn_futex);
159
        return 0;
1351 palkovsky 160
    }
1392 palkovsky 161
    conn = hash_table_get_instance(hlp, connection_t, link);
1351 palkovsky 162
 
1392 palkovsky 163
    msg = malloc(sizeof(*msg));
164
    msg->callid = callid;
165
    msg->call = *call;
166
    list_append(&msg->link, &conn->msg_queue);
167
 
168
    if (!conn->active) {
169
        conn->active = 1;
170
        psthread_add_ready(conn->ptid);
171
    }
1351 palkovsky 172
 
1392 palkovsky 173
    futex_up(&conn_futex);
174
 
175
    return 1;
176
}
177
 
1404 palkovsky 178
/** Return new incoming message for current(thread-local) connection */
1392 palkovsky 179
ipc_callid_t async_get_call(ipc_call_t *call)
180
{
181
    msg_t *msg;
182
    ipc_callid_t callid;
183
    connection_t *conn;
184
 
185
    futex_down(&conn_futex);
186
 
187
    conn = PS_connection;
188
    /* If nothing in queue, wait until something appears */
189
    if (list_empty(&conn->msg_queue)) {
190
        conn->active = 0;
191
        psthread_schedule_next_adv(PS_TO_MANAGER);
1351 palkovsky 192
    }
193
 
1392 palkovsky 194
    msg = list_get_instance(conn->msg_queue.next, msg_t, link);
195
    list_remove(&msg->link);
196
    callid = msg->callid;
197
    *call = msg->call;
198
    free(msg);
199
 
200
    futex_up(&conn_futex);
201
    return callid;
1351 palkovsky 202
}
203
 
1404 palkovsky 204
/** Thread function that gets created on new connection
205
 *
206
 * This function is defined as a weak symbol - to be redefined in
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 * user code.
208
 */
1392 palkovsky 209
void client_connection(ipc_callid_t callid, ipc_call_t *call)
210
{
1404 palkovsky 211
    ipc_answer_fast(callid, ENOENT, 0, 0);
1392 palkovsky 212
}
1351 palkovsky 213
 
1404 palkovsky 214
/** Wrapper for client connection thread
215
 *
216
 * When new connection arrives, thread with this function is created.
217
 * It calls client_connection and does final cleanup.
218
 *
219
 * @parameter arg Connection structure pointer
220
 */
1392 palkovsky 221
static int connection_thread(void  *arg)
1351 palkovsky 222
{
1404 palkovsky 223
    unsigned long key;
224
    msg_t *msg;
225
 
1392 palkovsky 226
    /* Setup thread local connection pointer */
227
    PS_connection = (connection_t *)arg;
228
    client_connection(PS_connection->callid, &PS_connection->call);
229
 
1404 palkovsky 230
    /* Remove myself from connection hash table */
1392 palkovsky 231
    futex_down(&conn_futex);
1404 palkovsky 232
    key = PS_connection->in_phone_hash;
233
    hash_table_remove(&conn_hash_table, &key, 1);
1392 palkovsky 234
    futex_up(&conn_futex);
1404 palkovsky 235
    /* Answer all remaining messages with ehangup */
236
    while (!list_empty(&PS_connection->msg_queue)) {
237
        msg = list_get_instance(PS_connection->msg_queue.next, msg_t, link);
238
        list_remove(&msg->link);
239
        ipc_answer_fast(msg->callid, EHANGUP, 0, 0);
240
        free(msg);
241
    }
1351 palkovsky 242
}
1392 palkovsky 243
 
244
/** Create new thread for a new connection
245
 *
246
 * Creates new thread for connection, fills in connection
247
 * structures and inserts it into the hash table, so that
248
 * later we can easily do routing of messages to particular
249
 * threads.
250
 */
251
static void new_connection(ipc_callid_t callid, ipc_call_t *call)
252
{
253
    pstid_t ptid;
254
    connection_t *conn;
255
    unsigned long key;
256
 
257
    conn = malloc(sizeof(*conn));
258
    if (!conn) {
259
        ipc_answer_fast(callid, ENOMEM, 0, 0);
260
        return;
261
    }
262
    conn->in_phone_hash = IPC_GET_ARG3(*call);
263
    list_initialize(&conn->msg_queue);
264
    conn->ptid = psthread_create(connection_thread, conn);
265
    conn->callid = callid;
266
    conn->call = *call;
267
    conn->active = 1; /* We will activate it asap */
268
    list_initialize(&conn->link);
269
    if (!conn->ptid) {
270
        free(conn);
271
        ipc_answer_fast(callid, ENOMEM, 0, 0);
272
        return;
273
    }
274
    key = conn->in_phone_hash;
275
    futex_down(&conn_futex);
276
    /* Add connection to hash table */
277
    hash_table_insert(&conn_hash_table, &key, &conn->link);
278
    futex_up(&conn_futex);
279
 
280
    psthread_add_ready(conn->ptid);
281
}
282
 
283
/** Handle call to a task */
284
static void handle_call(ipc_callid_t callid, ipc_call_t *call)
285
{
286
    if (route_call(callid, call))
287
        return;
288
 
289
    switch (IPC_GET_METHOD(*call)) {
290
    case IPC_M_INTERRUPT:
291
        break;
292
    case IPC_M_CONNECT_ME_TO:
293
        /* Open new connection with thread etc. */
294
        new_connection(callid, call);
295
        break;
296
    default:
297
        ipc_answer_fast(callid, EHANGUP, 0, 0);
298
    }
299
}
300
 
301
/** Endless loop dispatching incoming calls and answers */
302
int async_manager()
303
{
304
    ipc_call_t call;
305
    ipc_callid_t callid;
306
 
307
    while (1) {
308
        if (psthread_schedule_next_adv(PS_FROM_MANAGER)) {
309
            futex_up(&conn_futex); /* conn_futex is always held
310
                        * when entering manager thread
311
                        */
312
            continue;
313
        }
314
        callid = ipc_wait_cycle(&call,SYNCH_NO_TIMEOUT,SYNCH_BLOCKING);
315
 
316
        if (callid & IPC_CALLID_ANSWERED)
317
            continue;
318
        handle_call(callid, &call);
319
    }
320
}
321
 
1404 palkovsky 322
/** Function to start async_manager as a standalone thread
323
 *
324
 * When more kernel threads are used, one async manager should
325
 * exist per thread. The particular implementation may change,
326
 * currently one async_manager is started automatically per kernel
327
 * thread except main thread.
328
 */
1392 palkovsky 329
static int async_manager_thread(void *arg)
330
{
331
    futex_up(&conn_futex); /* conn_futex is always locked when entering
332
                * manager */
333
    async_manager();
334
}
335
 
336
/** Add one manager to manager list */
337
void async_create_manager(void)
338
{
339
    pstid_t ptid;
340
 
341
    ptid = psthread_create(async_manager_thread, NULL);
342
    psthread_add_manager(ptid);
343
}
344
 
345
/** Remove one manager from manager list */
346
void async_destroy_manager(void)
347
{
348
    psthread_remove_manager();
349
}
350
 
351
/** Initialize internal structures needed for async manager */
352
int _async_init(void)
353
{
1404 palkovsky 354
    if (!hash_table_create(&conn_hash_table, CONN_HASH_TABLE_CHAINS, 1, &conn_hash_table_ops)) {
1392 palkovsky 355
        printf("%s: cannot create hash table\n", "async");
356
        return ENOMEM;
357
    }
358
 
359
}